<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.nacg.ca/role/AccountingPronouncementsRecentlyAdopted" xlink:href="noa-20181231.xsd#AccountingPronouncementsRecentlyAdopted" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AccountingPronouncementsRecentlyAdoptedScheduleOfEffectsOfAdoptingNewRevenueStandardDetails" xlink:href="noa-20181231.xsd#AccountingPronouncementsRecentlyAdoptedScheduleOfEffectsOfAdoptingNewRevenueStandardDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AccountingPronouncementsRecentlyAdoptedTables" xlink:href="noa-20181231.xsd#AccountingPronouncementsRecentlyAdoptedTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AccountsReceivable" xlink:href="noa-20181231.xsd#AccountsReceivable" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AccountsReceivableDetails" xlink:href="noa-20181231.xsd#AccountsReceivableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AccountsReceivableTables" xlink:href="noa-20181231.xsd#AccountsReceivableTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AccruedLiabilities" xlink:href="noa-20181231.xsd#AccruedLiabilities" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AccruedLiabilitiesDetails" xlink:href="noa-20181231.xsd#AccruedLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AccruedLiabilitiesTables" xlink:href="noa-20181231.xsd#AccruedLiabilitiesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/Acquisitions" xlink:href="noa-20181231.xsd#Acquisitions" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AcquisitionsHeavyConstructionFleetAndRelatedAssetsDetails" xlink:href="noa-20181231.xsd#AcquisitionsHeavyConstructionFleetAndRelatedAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AcquisitionsInvestmentsInAffiliatesAndJointVenturesDetails" xlink:href="noa-20181231.xsd#AcquisitionsInvestmentsInAffiliatesAndJointVenturesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AcquisitionsTables" xlink:href="noa-20181231.xsd#AcquisitionsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AssetsHeldForSale" xlink:href="noa-20181231.xsd#AssetsHeldForSale" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/AssetsHeldForSaleDetails" xlink:href="noa-20181231.xsd#AssetsHeldForSaleDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/CapitalLeaseObligations" xlink:href="noa-20181231.xsd#CapitalLeaseObligations" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/CapitalLeaseObligationsDetails" xlink:href="noa-20181231.xsd#CapitalLeaseObligationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/CapitalLeaseObligationsTables" xlink:href="noa-20181231.xsd#CapitalLeaseObligationsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/Commitments" xlink:href="noa-20181231.xsd#Commitments" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/CommitmentsDetails" xlink:href="noa-20181231.xsd#CommitmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/CommitmentsTables" xlink:href="noa-20181231.xsd#CommitmentsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/ComparativeFigures" xlink:href="noa-20181231.xsd#ComparativeFigures" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/ConsolidatedBalanceSheets" xlink:href="noa-20181231.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="noa-20181231.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/ConsolidatedStatementsOfCashFlows" xlink:href="noa-20181231.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/ConsolidatedStatementsOfChangesInShareholdersEquity" xlink:href="noa-20181231.xsd#ConsolidatedStatementsOfChangesInShareholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/ConsolidatedStatementsOfChangesInStockholdersEquityParenthetical" xlink:href="noa-20181231.xsd#ConsolidatedStatementsOfChangesInStockholdersEquityParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/ConsolidatedStatementsOfOperationsAndComprehensiveIncome" xlink:href="noa-20181231.xsd#ConsolidatedStatementsOfOperationsAndComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/Contingencies" xlink:href="noa-20181231.xsd#Contingencies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/DocumentAndEntityInformation" xlink:href="noa-20181231.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/EmployeeBenefitPlans" xlink:href="noa-20181231.xsd#EmployeeBenefitPlans" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/EmployeeBenefitPlansDetails" xlink:href="noa-20181231.xsd#EmployeeBenefitPlansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagement" xlink:href="noa-20181231.xsd#FinancialInstrumentsAndRiskManagement" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementAssetsHeldForSaleDetails" xlink:href="noa-20181231.xsd#FinancialInstrumentsAndRiskManagementAssetsHeldForSaleDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementFinancialInstrumentsDetails" xlink:href="noa-20181231.xsd#FinancialInstrumentsAndRiskManagementFinancialInstrumentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementMaximumCreditExposureDetails" xlink:href="noa-20181231.xsd#FinancialInstrumentsAndRiskManagementMaximumCreditExposureDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementRiskManagementDetails" xlink:href="noa-20181231.xsd#FinancialInstrumentsAndRiskManagementRiskManagementDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementTables" xlink:href="noa-20181231.xsd#FinancialInstrumentsAndRiskManagementTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementTradeReceivablesDetails" xlink:href="noa-20181231.xsd#FinancialInstrumentsAndRiskManagementTradeReceivablesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/IncomeTaxes" xlink:href="noa-20181231.xsd#IncomeTaxes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/IncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails" xlink:href="noa-20181231.xsd#IncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/IncomeTaxesExpenseBenefitDetails" xlink:href="noa-20181231.xsd#IncomeTaxesExpenseBenefitDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/IncomeTaxesExpirationOfNonCapitalLossesForIncomeTaxPurposesDetails" xlink:href="noa-20181231.xsd#IncomeTaxesExpirationOfNonCapitalLossesForIncomeTaxPurposesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/IncomeTaxesNarrativeDetails" xlink:href="noa-20181231.xsd#IncomeTaxesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/IncomeTaxesTables" xlink:href="noa-20181231.xsd#IncomeTaxesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InterestExpense" xlink:href="noa-20181231.xsd#InterestExpense" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InterestExpenseDetails" xlink:href="noa-20181231.xsd#InterestExpenseDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InterestExpenseTables" xlink:href="noa-20181231.xsd#InterestExpenseTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVentures" xlink:href="noa-20181231.xsd#InvestmentsInAffiliatesAndJointVentures" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesBalanceSheetsDetails" xlink:href="noa-20181231.xsd#InvestmentsInAffiliatesAndJointVenturesBalanceSheetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesNarrativeDetails" xlink:href="noa-20181231.xsd#InvestmentsInAffiliatesAndJointVenturesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesOwnershipPercentagesDetails" xlink:href="noa-20181231.xsd#InvestmentsInAffiliatesAndJointVenturesOwnershipPercentagesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesStatementsOfOperationsAndComprehensiveIncomeDetails" xlink:href="noa-20181231.xsd#InvestmentsInAffiliatesAndJointVenturesStatementsOfOperationsAndComprehensiveIncomeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesSummaryOfMovementInInvestmentsInAffiliatesAndJointVenturesDetails" xlink:href="noa-20181231.xsd#InvestmentsInAffiliatesAndJointVenturesSummaryOfMovementInInvestmentsInAffiliatesAndJointVenturesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesTables" xlink:href="noa-20181231.xsd#InvestmentsInAffiliatesAndJointVenturesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebt" xlink:href="noa-20181231.xsd#LongTermDebt" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebtConvertibleDebentureDetails" xlink:href="noa-20181231.xsd#LongTermDebtConvertibleDebentureDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebtCreditFacilityNarrativeDetails" xlink:href="noa-20181231.xsd#LongTermDebtCreditFacilityNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebtDeferredFinancingDetails" xlink:href="noa-20181231.xsd#LongTermDebtDeferredFinancingDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebtMortgageDetails" xlink:href="noa-20181231.xsd#LongTermDebtMortgageDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebtPromissoryNotesDetails" xlink:href="noa-20181231.xsd#LongTermDebtPromissoryNotesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebtScheduleOfCreditFacilitiesDetails" xlink:href="noa-20181231.xsd#LongTermDebtScheduleOfCreditFacilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebtScheduleOfLongTermDebtDetails" xlink:href="noa-20181231.xsd#LongTermDebtScheduleOfLongTermDebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebtScheduleOfPromissoryNotesDetails" xlink:href="noa-20181231.xsd#LongTermDebtScheduleOfPromissoryNotesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/LongTermDebtTables" xlink:href="noa-20181231.xsd#LongTermDebtTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/NatureOfOperations" xlink:href="noa-20181231.xsd#NatureOfOperations" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherAssets" xlink:href="noa-20181231.xsd#OtherAssets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherAssetsDeferredFinancingCostsDetails" xlink:href="noa-20181231.xsd#OtherAssetsDeferredFinancingCostsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherAssetsDeferredLeaseInducementsAssetDetails" xlink:href="noa-20181231.xsd#OtherAssetsDeferredLeaseInducementsAssetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherAssetsIntangibleAssetsDetails" xlink:href="noa-20181231.xsd#OtherAssetsIntangibleAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherAssetsScheduleOfOtherAssetsDetails" xlink:href="noa-20181231.xsd#OtherAssetsScheduleOfOtherAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherAssetsTables" xlink:href="noa-20181231.xsd#OtherAssetsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherInformation" xlink:href="noa-20181231.xsd#OtherInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherInformationNonCashDetails" xlink:href="noa-20181231.xsd#OtherInformationNonCashDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherInformationOtherInformationSupplementalCashFlowInformationDetails" xlink:href="noa-20181231.xsd#OtherInformationOtherInformationSupplementalCashFlowInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherInformationTables" xlink:href="noa-20181231.xsd#OtherInformationTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherLongTermObligations" xlink:href="noa-20181231.xsd#OtherLongTermObligations" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherLongTermObligationsOtherLiabilitiesAndObligationsDetails" xlink:href="noa-20181231.xsd#OtherLongTermObligationsOtherLiabilitiesAndObligationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherLongTermObligationsScheduleOfOtherLongTermObligationsDetails" xlink:href="noa-20181231.xsd#OtherLongTermObligationsScheduleOfOtherLongTermObligationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/OtherLongTermObligationsTables" xlink:href="noa-20181231.xsd#OtherLongTermObligationsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/PrepaidExpensesAndDeposits" xlink:href="noa-20181231.xsd#PrepaidExpensesAndDeposits" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/PrepaidExpensesAndDepositsDetails" xlink:href="noa-20181231.xsd#PrepaidExpensesAndDepositsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/PrepaidExpensesAndDepositsTables" xlink:href="noa-20181231.xsd#PrepaidExpensesAndDepositsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/PropertyPlantAndEquipment" xlink:href="noa-20181231.xsd#PropertyPlantAndEquipment" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/PropertyPlantAndEquipmentDetails" xlink:href="noa-20181231.xsd#PropertyPlantAndEquipmentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/PropertyPlantAndEquipmentTables" xlink:href="noa-20181231.xsd#PropertyPlantAndEquipmentTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RecentAccountingPronouncementsNotYetAdopted" xlink:href="noa-20181231.xsd#RecentAccountingPronouncementsNotYetAdopted" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RelatedPartyTransactions" xlink:href="noa-20181231.xsd#RelatedPartyTransactions" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RelatedPartyTransactionsDetails" xlink:href="noa-20181231.xsd#RelatedPartyTransactionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RelatedPartyTransactionsTables" xlink:href="noa-20181231.xsd#RelatedPartyTransactionsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/Revenue" xlink:href="noa-20181231.xsd#Revenue" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RevenueContractBalancesDetails" xlink:href="noa-20181231.xsd#RevenueContractBalancesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RevenueContractCostsDetails" xlink:href="noa-20181231.xsd#RevenueContractCostsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RevenueDisaggregationOfRevenueDetails" xlink:href="noa-20181231.xsd#RevenueDisaggregationOfRevenueDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RevenueEstimatedRevenueExpectedToBeRecognizedInFutureRelatedToPerformanceObligationsDetails" xlink:href="noa-20181231.xsd#RevenueEstimatedRevenueExpectedToBeRecognizedInFutureRelatedToPerformanceObligationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RevenueScheduleOfMajorCustomersDetails" xlink:href="noa-20181231.xsd#RevenueScheduleOfMajorCustomersDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RevenueTables" xlink:href="noa-20181231.xsd#RevenueTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/RevenueUnpricedContractModificationsDetails" xlink:href="noa-20181231.xsd#RevenueUnpricedContractModificationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/Shares" xlink:href="noa-20181231.xsd#Shares" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SharesCommonSharesDetails" xlink:href="noa-20181231.xsd#SharesCommonSharesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SharesDividendsDetails" xlink:href="noa-20181231.xsd#SharesDividendsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SharesNetIncomePerShareDetails" xlink:href="noa-20181231.xsd#SharesNetIncomePerShareDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SharesSharePurchaseProgramDetails" xlink:href="noa-20181231.xsd#SharesSharePurchaseProgramDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SharesTables" xlink:href="noa-20181231.xsd#SharesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SignificantAccountingPolicies" xlink:href="noa-20181231.xsd#SignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SignificantAccountingPoliciesIntangibleAssetsDetails" xlink:href="noa-20181231.xsd#SignificantAccountingPoliciesIntangibleAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SignificantAccountingPoliciesPolicies" xlink:href="noa-20181231.xsd#SignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SignificantAccountingPoliciesPropertyPlantAndEquipmentDetails" xlink:href="noa-20181231.xsd#SignificantAccountingPoliciesPropertyPlantAndEquipmentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SignificantAccountingPoliciesStockBasedCompensationDetails" xlink:href="noa-20181231.xsd#SignificantAccountingPoliciesStockBasedCompensationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/SignificantAccountingPoliciesTables" xlink:href="noa-20181231.xsd#SignificantAccountingPoliciesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/StockBasedCompensation" xlink:href="noa-20181231.xsd#StockBasedCompensation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/StockBasedCompensationOptionsByExercisePriceRangeDetails" xlink:href="noa-20181231.xsd#StockBasedCompensationOptionsByExercisePriceRangeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/StockBasedCompensationPerformanceAndDeferredStockUnitPlanDetails" xlink:href="noa-20181231.xsd#StockBasedCompensationPerformanceAndDeferredStockUnitPlanDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/StockBasedCompensationRestrictedShareUnitPlanDetails" xlink:href="noa-20181231.xsd#StockBasedCompensationRestrictedShareUnitPlanDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/StockBasedCompensationShareOptionsPlanDetails" xlink:href="noa-20181231.xsd#StockBasedCompensationShareOptionsPlanDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/StockBasedCompensationStockBasedCompensationExpensesDetails" xlink:href="noa-20181231.xsd#StockBasedCompensationStockBasedCompensationExpensesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.nacg.ca/role/StockBasedCompensationTables" xlink:href="noa-20181231.xsd#StockBasedCompensationTables" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AccountingPronouncementsRecentlyAdopted" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AccountingPronouncementsRecentlyAdoptedScheduleOfEffectsOfAdoptingNewRevenueStandardDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems" xlink:label="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable" xlink:label="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_B8EDE8D2E9550B3F60C324FE0B4600BC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_B8EDE8D2E9550B3F60C324FE0B4600BC" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_F613A96091FC0ABC405A24FE0B46BE1B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_B8EDE8D2E9550B3F60C324FE0B4600BC" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_F613A96091FC0ABC405A24FE0B46BE1B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_B358D0C281A951D4637824FE0B46A97A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_F613A96091FC0ABC405A24FE0B46BE1B" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_B358D0C281A951D4637824FE0B46A97A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_B358D0C281A951D4637824FE0B46A97A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_F613A96091FC0ABC405A24FE0B46BE1B" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_B358D0C281A951D4637824FE0B46A97A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member" xlink:label="loc_us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_1B3C4FD430A9188171EC24FE0B476619" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_B358D0C281A951D4637824FE0B46A97A" xlink:to="loc_us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_1B3C4FD430A9188171EC24FE0B476619" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CalculatedUnderRevenueGuidanceInEffectBeforeTopic606Member" xlink:label="loc_us-gaap_CalculatedUnderRevenueGuidanceInEffectBeforeTopic606Member_EC61ED4C4DF172F943DC24FE0B470972" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_B358D0C281A951D4637824FE0B46A97A" xlink:to="loc_us-gaap_CalculatedUnderRevenueGuidanceInEffectBeforeTopic606Member_EC61ED4C4DF172F943DC24FE0B470972" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_D3209BA5A0A10F5EDCAA24FE0B47D5AC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionTable_B8EDE8D2E9550B3F60C324FE0B4600BC" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_D3209BA5A0A10F5EDCAA24FE0B47D5AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_7175C9CB94DF69ABEAD724FE0B472302_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_D3209BA5A0A10F5EDCAA24FE0B47D5AC" xlink:to="loc_us-gaap_TypeOfAdoptionMember_7175C9CB94DF69ABEAD724FE0B472302_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_7175C9CB94DF69ABEAD724FE0B472302" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_D3209BA5A0A10F5EDCAA24FE0B47D5AC" xlink:to="loc_us-gaap_TypeOfAdoptionMember_7175C9CB94DF69ABEAD724FE0B472302" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountingStandardsUpdate201409Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201409Member_18CBC295BDBA33BFC36824FE0B48C431" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_7175C9CB94DF69ABEAD724FE0B472302" xlink:to="loc_us-gaap_AccountingStandardsUpdate201409Member_18CBC295BDBA33BFC36824FE0B48C431" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_9DAE1C3FAB8A9DD0488E24FE0B48FFD1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_9DAE1C3FAB8A9DD0488E24FE0B48FFD1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_26F5AF8CB993302BF83624FE0B486BB0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_AssetsAbstract_26F5AF8CB993302BF83624FE0B486BB0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_F50C54F1AE39D37FA2D724FE0B493841" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_26F5AF8CB993302BF83624FE0B486BB0" xlink:to="loc_us-gaap_AssetsCurrentAbstract_F50C54F1AE39D37FA2D724FE0B493841" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsAndOtherReceivablesNetCurrent" xlink:label="loc_us-gaap_AccountsAndOtherReceivablesNetCurrent_C22531D7802137BAC04524FE0B490CA0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_F50C54F1AE39D37FA2D724FE0B493841" xlink:to="loc_us-gaap_AccountsAndOtherReceivablesNetCurrent_C22531D7802137BAC04524FE0B490CA0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerAssetNetCurrent" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetCurrent_ED4639D31ABAEF997BDD24FE0B498E6F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_F50C54F1AE39D37FA2D724FE0B493841" xlink:to="loc_us-gaap_ContractWithCustomerAssetNetCurrent_ED4639D31ABAEF997BDD24FE0B498E6F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_UnbilledContractsReceivable" xlink:label="loc_us-gaap_UnbilledContractsReceivable_8F938A91B8E11B2E8F0B24FE0B49E66A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_F50C54F1AE39D37FA2D724FE0B493841" xlink:to="loc_us-gaap_UnbilledContractsReceivable_8F938A91B8E11B2E8F0B24FE0B49E66A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_C92AFB0B1C1C02EC3D7324FE0B49E74F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_F50C54F1AE39D37FA2D724FE0B493841" xlink:to="loc_us-gaap_AssetsCurrent_C92AFB0B1C1C02EC3D7324FE0B49E74F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_AFAF565E47DFA87CDCBD24FE0B4A0C77" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_26F5AF8CB993302BF83624FE0B486BB0" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_AFAF565E47DFA87CDCBD24FE0B4A0C77" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_DA5FDD19AADB0948293824FE0B4AB2C9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_26F5AF8CB993302BF83624FE0B486BB0" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_DA5FDD19AADB0948293824FE0B4AB2C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_311BB36DDB81F70D4E3924FE0B4ABC4D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_26F5AF8CB993302BF83624FE0B486BB0" xlink:to="loc_us-gaap_Assets_311BB36DDB81F70D4E3924FE0B4ABC4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_546A4E27994F96D7BE2D24FE0B4AC354" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_546A4E27994F96D7BE2D24FE0B4AC354" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_0E5B97E5871ED624F7AD24FE0B4A780A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_546A4E27994F96D7BE2D24FE0B4AC354" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_0E5B97E5871ED624F7AD24FE0B4A780A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_204528C25D499B07232224FE0B4BEE2D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_0E5B97E5871ED624F7AD24FE0B4A780A" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_204528C25D499B07232224FE0B4BEE2D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BillingsInExcessOfCostCurrent" xlink:label="loc_us-gaap_BillingsInExcessOfCostCurrent_E058D9FC6663CF8FA49C24FE0B4B3A43" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_0E5B97E5871ED624F7AD24FE0B4A780A" xlink:to="loc_us-gaap_BillingsInExcessOfCostCurrent_E058D9FC6663CF8FA49C24FE0B4B3A43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_0CC551FE8E4D6D68586F24FE0B4BDD52" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_0E5B97E5871ED624F7AD24FE0B4A780A" xlink:to="loc_us-gaap_LiabilitiesCurrent_0CC551FE8E4D6D68586F24FE0B4BDD52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_79AEE12976E1561AFBF324FE0B4CA954" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_546A4E27994F96D7BE2D24FE0B4AC354" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_79AEE12976E1561AFBF324FE0B4CA954" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_06AC32AE9321AF5256F524FE0B4C7DD4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_546A4E27994F96D7BE2D24FE0B4AC354" xlink:to="loc_us-gaap_Liabilities_06AC32AE9321AF5256F524FE0B4C7DD4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_547F5EE923AA39B1827824FE0B4C516C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_546A4E27994F96D7BE2D24FE0B4AC354" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_547F5EE923AA39B1827824FE0B4C516C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_ABC2CE599046FC750FD424FE0B4C4133" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_547F5EE923AA39B1827824FE0B4C516C" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_ABC2CE599046FC750FD424FE0B4C4133" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_DB674CEFF247FFC348FA24FE0B4C242E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_547F5EE923AA39B1827824FE0B4C516C" xlink:to="loc_us-gaap_StockholdersEquity_DB674CEFF247FFC348FA24FE0B4C242E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_C4751EECC42379E52D7B24FE0B4D53D7" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_546A4E27994F96D7BE2D24FE0B4AC354" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_C4751EECC42379E52D7B24FE0B4D53D7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_946FE3AA41F1AB9FC2FD24FE0B4DA554" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_946FE3AA41F1AB9FC2FD24FE0B4DA554" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ProjectCost" xlink:label="loc_noa_ProjectCost_398A0CCECB19028A374324FE0B4D0B4C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_noa_ProjectCost_398A0CCECB19028A374324FE0B4D0B4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_73F6D05652A09B48098024FE0B4DCF50" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_GrossProfit_73F6D05652A09B48098024FE0B4DCF50" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_AC64C5BFA5770007EE3324FE0B4DC39D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_OperatingIncomeLoss_AC64C5BFA5770007EE3324FE0B4DC39D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_72747C0543325652CB8124FE0B4D8643" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_72747C0543325652CB8124FE0B4D8643" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_A80996CAB22C3F6AE88F24FE0B4E84C4" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_A80996CAB22C3F6AE88F24FE0B4E84C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_43BF8A261CFC7F05066A24FE0B4E9EF7" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_43BF8A261CFC7F05066A24FE0B4E9EF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_3D2C6A02E97A4C66CC5024FE0B4E58EE" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_3D2C6A02E97A4C66CC5024FE0B4E58EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_EBE57BFC8CB1BBFBE91424FE0B4EEFA6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_3D2C6A02E97A4C66CC5024FE0B4E58EE" xlink:to="loc_us-gaap_ProfitLoss_EBE57BFC8CB1BBFBE91424FE0B4EEFA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_EA49798B1AC98A5D43E724FE0B4F6614" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_3D2C6A02E97A4C66CC5024FE0B4E58EE" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_EA49798B1AC98A5D43E724FE0B4F6614" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapital" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapital_1AC40FBFF06AB0C6ADA024FE0B4F2978" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_3D2C6A02E97A4C66CC5024FE0B4E58EE" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapital_1AC40FBFF06AB0C6ADA024FE0B4F2978" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_7C59F1B44EB4196C07CA24FE0B4F042D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_3D2C6A02E97A4C66CC5024FE0B4E58EE" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_7C59F1B44EB4196C07CA24FE0B4F042D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_993D5CAA7E52AAC2639424FE0B4F4B0F" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueInitialApplicationPeriodCumulativeEffectTransitionLineItems_B6C4484FFCFF2EB0340124FE0B48EEDF" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_993D5CAA7E52AAC2639424FE0B4F4B0F" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AccountingPronouncementsRecentlyAdoptedTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AccountsReceivable" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AccountsReceivableDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AccountsReceivableTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AccruedLiabilities" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AccruedLiabilitiesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AccruedLiabilitiesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/Acquisitions" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AcquisitionsHeavyConstructionFleetAndRelatedAssetsDetails" xlink:type="extended">
    <link:loc xlink:href="noa-20181231.xsd#noa_ScheduleofAssetAcquisitionLineItems" xlink:label="loc_noa_ScheduleofAssetAcquisitionLineItems_957D082534CA5C293B8F24FE0B34B935" xlink:type="locator" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ScheduleofAssetAcquisitionTable" xlink:label="loc_noa_ScheduleofAssetAcquisitionTable_8BD04A969465CDD0D90724FE0B331C60" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_noa_ScheduleofAssetAcquisitionLineItems_957D082534CA5C293B8F24FE0B34B935" xlink:to="loc_noa_ScheduleofAssetAcquisitionTable_8BD04A969465CDD0D90724FE0B331C60" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AssetAcquisitionAxis" xlink:label="loc_noa_AssetAcquisitionAxis_78D395B63C3F3A88C1A824FE0B33658A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_noa_ScheduleofAssetAcquisitionTable_8BD04A969465CDD0D90724FE0B331C60" xlink:to="loc_noa_AssetAcquisitionAxis_78D395B63C3F3A88C1A824FE0B33658A" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AssetAcquisitionDomain" xlink:label="loc_noa_AssetAcquisitionDomain_2CDA9113E3AF2FFABAF924FE0B331701_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_noa_AssetAcquisitionAxis_78D395B63C3F3A88C1A824FE0B33658A" xlink:to="loc_noa_AssetAcquisitionDomain_2CDA9113E3AF2FFABAF924FE0B331701_default" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AssetAcquisitionDomain" xlink:label="loc_noa_AssetAcquisitionDomain_2CDA9113E3AF2FFABAF924FE0B331701" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_noa_AssetAcquisitionAxis_78D395B63C3F3A88C1A824FE0B33658A" xlink:to="loc_noa_AssetAcquisitionDomain_2CDA9113E3AF2FFABAF924FE0B331701" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AcquisitionOfAeconConstructionGroupInc.sHeavyConstructionEquipmentFleetAndRelatedAssetsMember" xlink:label="loc_noa_AcquisitionOfAeconConstructionGroupInc.sHeavyConstructionEquipmentFleetAndRelatedAssetsMember_1F179450995D7120633E24FE0B345ACF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_AssetAcquisitionDomain_2CDA9113E3AF2FFABAF924FE0B331701" xlink:to="loc_noa_AcquisitionOfAeconConstructionGroupInc.sHeavyConstructionEquipmentFleetAndRelatedAssetsMember_1F179450995D7120633E24FE0B345ACF" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_PaymentsforAssetAcquisitions" xlink:label="loc_noa_PaymentsforAssetAcquisitions_62CC29EDD049098EB0B324FE0B34FE0B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleofAssetAcquisitionLineItems_957D082534CA5C293B8F24FE0B34B935" xlink:to="loc_noa_PaymentsforAssetAcquisitions_62CC29EDD049098EB0B324FE0B34FE0B" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AssetAcquisitionInitialPayment" xlink:label="loc_noa_AssetAcquisitionInitialPayment_98C153F046255533F68B24FE0B3454F8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleofAssetAcquisitionLineItems_957D082534CA5C293B8F24FE0B34B935" xlink:to="loc_noa_AssetAcquisitionInitialPayment_98C153F046255533F68B24FE0B3454F8" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AssetAcquisitionCapitalLeasesAndEquipmentRelatedPromissoryNotes" xlink:label="loc_noa_AssetAcquisitionCapitalLeasesAndEquipmentRelatedPromissoryNotes_EEADA36AC42EAFA7550424FE0B359B66" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleofAssetAcquisitionLineItems_957D082534CA5C293B8F24FE0B34B935" xlink:to="loc_noa_AssetAcquisitionCapitalLeasesAndEquipmentRelatedPromissoryNotes_EEADA36AC42EAFA7550424FE0B359B66" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AssetAcquisitionNumberOfInstallmentPayments" xlink:label="loc_noa_AssetAcquisitionNumberOfInstallmentPayments_F125E01FDE9C0FBDBB6524FE0B352B24" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleofAssetAcquisitionLineItems_957D082534CA5C293B8F24FE0B34B935" xlink:to="loc_noa_AssetAcquisitionNumberOfInstallmentPayments_F125E01FDE9C0FBDBB6524FE0B352B24" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AssetAcquisitionTransactionCosts" xlink:label="loc_noa_AssetAcquisitionTransactionCosts_443E537A645510BC67BD24FE0B35DD99" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleofAssetAcquisitionLineItems_957D082534CA5C293B8F24FE0B34B935" xlink:to="loc_noa_AssetAcquisitionTransactionCosts_443E537A645510BC67BD24FE0B35DD99" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AcquisitionsInvestmentsInAffiliatesAndJointVenturesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_B50296D6C6840FBBB00024FD91BB94E4" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_95148DD5CF70E81E14B924FD91B732D8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_B50296D6C6840FBBB00024FD91BB94E4" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_95148DD5CF70E81E14B924FD91B732D8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_DFBC9590FD21FABDA9D124FD91B85DBB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_95148DD5CF70E81E14B924FD91B732D8" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_DFBC9590FD21FABDA9D124FD91B85DBB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_1B5FB6B898DF89C831A324FD91B9F755_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_DFBC9590FD21FABDA9D124FD91B85DBB" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_1B5FB6B898DF89C831A324FD91B9F755_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_1B5FB6B898DF89C831A324FD91B9F755" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_DFBC9590FD21FABDA9D124FD91B85DBB" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_1B5FB6B898DF89C831A324FD91B9F755" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaLogisticsLimitedMember" xlink:label="loc_noa_NunaLogisticsLimitedMember_0939F043B58B76A78CB824FD91B9F022" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_1B5FB6B898DF89C831A324FD91B9F755" xlink:to="loc_noa_NunaLogisticsLimitedMember_0939F043B58B76A78CB824FD91B9F022" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaEastLtd.Member" xlink:label="loc_noa_NunaEastLtd.Member_77F35C95712E37A5D5DF24FD91B9ED8F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_1B5FB6B898DF89C831A324FD91B9F755" xlink:to="loc_noa_NunaEastLtd.Member_77F35C95712E37A5D5DF24FD91B9ED8F" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaPangContractingLtd.Member" xlink:label="loc_noa_NunaPangContractingLtd.Member_92AD9F719502FF264AA824FD91BA2835" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_1B5FB6B898DF89C831A324FD91B9F755" xlink:to="loc_noa_NunaPangContractingLtd.Member_92AD9F719502FF264AA824FD91BA2835" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaWestMiningLtd.Member" xlink:label="loc_noa_NunaWestMiningLtd.Member_F96D04E1B360CCAE16DC24FD91BA33CE" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_1B5FB6B898DF89C831A324FD91B9F755" xlink:to="loc_noa_NunaWestMiningLtd.Member_F96D04E1B360CCAE16DC24FD91BA33CE" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaLogisticsPartnershipMember" xlink:label="loc_noa_NunaLogisticsPartnershipMember_E38451905266A031549424FD91BA54A7" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_1B5FB6B898DF89C831A324FD91B9F755" xlink:to="loc_noa_NunaLogisticsPartnershipMember_E38451905266A031549424FD91BA54A7" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_F7DE9F953EDB72DAA57324FD91BA7CED" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_95148DD5CF70E81E14B924FD91B732D8" xlink:to="loc_dei_LegalEntityAxis_F7DE9F953EDB72DAA57324FD91BA7CED" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_EF6AD928B5F98E07DD2824FD91BAB3F7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_F7DE9F953EDB72DAA57324FD91BA7CED" xlink:to="loc_dei_EntityDomain_EF6AD928B5F98E07DD2824FD91BAB3F7_default" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2018/dei-2018-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_EF6AD928B5F98E07DD2824FD91BAB3F7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_F7DE9F953EDB72DAA57324FD91BA7CED" xlink:to="loc_dei_EntityDomain_EF6AD928B5F98E07DD2824FD91BAB3F7" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_KitikmeotCorporationMember" xlink:label="loc_noa_KitikmeotCorporationMember_489EF48C305C36B6D30C24FD91BB23D4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_EF6AD928B5F98E07DD2824FD91BAB3F7" xlink:to="loc_noa_KitikmeotCorporationMember_489EF48C305C36B6D30C24FD91BB23D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_18CFC312647E04C62B1324FD91BB22D9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_B50296D6C6840FBBB00024FD91BB94E4" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_18CFC312647E04C62B1324FD91BB22D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" xlink:label="loc_us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts_04D950A62F3D29896A9E24FD91BB7346" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_B50296D6C6840FBBB00024FD91BB94E4" xlink:to="loc_us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts_04D950A62F3D29896A9E24FD91BB7346" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_C3F2DD9C9D850D918B9F24FD91BC55AC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_B50296D6C6840FBBB00024FD91BB94E4" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_C3F2DD9C9D850D918B9F24FD91BC55AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_0C94E3CAC2FE42705BCD24FD91BC5478" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_B50296D6C6840FBBB00024FD91BB94E4" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_0C94E3CAC2FE42705BCD24FD91BC5478" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract_75188F4525E3195B432024FD91BC64D6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_0C94E3CAC2FE42705BCD24FD91BC5478" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract_75188F4525E3195B432024FD91BC64D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_8E3D78465BDB9042393224FD91BE81D2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract_75188F4525E3195B432024FD91BC64D6" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_8E3D78465BDB9042393224FD91BE81D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_BE7193D7C6184D03747224FD91BE10F6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_8E3D78465BDB9042393224FD91BE81D2" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_BE7193D7C6184D03747224FD91BE10F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_F441EED031B06596FB0424FD91BFD2CA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_8E3D78465BDB9042393224FD91BE81D2" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_F441EED031B06596FB0424FD91BFD2CA" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedContractAssets" xlink:label="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedContractAssets_20FCE6FE18BAFEB885E724FD91BFC6EC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_8E3D78465BDB9042393224FD91BE81D2" xlink:to="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedContractAssets_20FCE6FE18BAFEB885E724FD91BFC6EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_63727136B7322E9108C524FD91BFCFAB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_8E3D78465BDB9042393224FD91BE81D2" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_63727136B7322E9108C524FD91BFCFAB" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedPrepaidExpensesAndDeposits" xlink:label="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedPrepaidExpensesAndDeposits_B7C87C56F75B4510217E24FD91C0604C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_8E3D78465BDB9042393224FD91BE81D2" xlink:to="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedPrepaidExpensesAndDeposits_B7C87C56F75B4510217E24FD91C0604C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_DBE607F40AE1A6D93B3D24FD91C0040C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_8E3D78465BDB9042393224FD91BE81D2" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_DBE607F40AE1A6D93B3D24FD91C0040C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_B11E890A451D29E52C3824FD91C0CCFE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract_75188F4525E3195B432024FD91BC64D6" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_B11E890A451D29E52C3824FD91C0CCFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_C9BC8DAFFB3ED249EA6324FD91C03A51" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract_75188F4525E3195B432024FD91BC64D6" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_C9BC8DAFFB3ED249EA6324FD91C03A51" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedInvestmentInAffiliatesAndJointVentures" xlink:label="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedInvestmentInAffiliatesAndJointVentures_A06F80AD3FFE199739CA24FD91C0918C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract_75188F4525E3195B432024FD91BC64D6" xlink:to="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedInvestmentInAffiliatesAndJointVentures_A06F80AD3FFE199739CA24FD91C0918C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_C7AB7967ADAF5524520B24FD91C0EC99" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract_75188F4525E3195B432024FD91BC64D6" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_C7AB7967ADAF5524520B24FD91C0EC99" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_0C94E3CAC2FE42705BCD24FD91BC5478" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_1B856AF73FF284D8A8B724FD91C16F6E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_1B856AF73FF284D8A8B724FD91C16F6E" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesAccruedLiabilities" xlink:label="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesAccruedLiabilities_D0076703810561A7B94424FD91C12EC5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesAccruedLiabilities_D0076703810561A7B94424FD91C12EC5" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesContractLiabilities" xlink:label="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesContractLiabilities_B5DB96A3B509359FD7EC24FD91C13A91" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesContractLiabilities_B5DB96A3B509359FD7EC24FD91C13A91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt_52BC95273973FB03FE1E24FD91C1E18E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLongTermDebt_52BC95273973FB03FE1E24FD91C1E18E" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesCapitalLeaseObligations" xlink:label="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesCapitalLeaseObligations_D87CCBCFACC7B718715724FD91C2B54D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_noa_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesCapitalLeaseObligations_D87CCBCFACC7B718715724FD91C2B54D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_21324A23568239CC11C724FD91C29D74" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_21324A23568239CC11C724FD91C29D74" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt_604B195013268799B5FD24FD92608168" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt_604B195013268799B5FD24FD92608168" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation_244E25CD23353CEEF96424FDACB39579" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation_244E25CD23353CEEF96424FDACB39579" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent_75A030F668E7E6BF817D24FD91C29602" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent_75A030F668E7E6BF817D24FD91C29602" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_92BD8DEC2C6FF23A143624FD91C267BC" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract_9883AF1C6F2AAB7CD43024FD91C12A5B" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_92BD8DEC2C6FF23A143624FD91C267BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_E0B281872921F82815E424FD91C203DE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract_0C94E3CAC2FE42705BCD24FD91BC5478" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_E0B281872921F82815E424FD91C203DE" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AcquisitionsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AssetsHeldForSale" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/AssetsHeldForSaleDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_7204FB6F4C96F132C84DBEA904E8F10B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_CF143D22A027EFAAD360BEA904E4BACA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_7204FB6F4C96F132C84DBEA904E8F10B" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_CF143D22A027EFAAD360BEA904E4BACA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_9FAF00712D9523B599D3BEA904E5DCA2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_CF143D22A027EFAAD360BEA904E4BACA" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_9FAF00712D9523B599D3BEA904E5DCA2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_A3107E4BEA13E251168FBEA904E7748B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_9FAF00712D9523B599D3BEA904E5DCA2" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_A3107E4BEA13E251168FBEA904E7748B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_A3107E4BEA13E251168FBEA904E7748B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_9FAF00712D9523B599D3BEA904E5DCA2" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_A3107E4BEA13E251168FBEA904E7748B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember" xlink:label="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_29A4C5077EF5FF0AE1F6BEA904E8B4B4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_A3107E4BEA13E251168FBEA904E7748B" xlink:to="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_29A4C5077EF5FF0AE1F6BEA904E8B4B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent" xlink:label="loc_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent_E19E97FBF0744272B244BEA904E9F50E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_7204FB6F4C96F132C84DBEA904E8F10B" xlink:to="loc_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent_E19E97FBF0744272B244BEA904E9F50E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_9056178DD3712FBBDA87BEA904E92474" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_7204FB6F4C96F132C84DBEA904E8F10B" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_9056178DD3712FBBDA87BEA904E92474" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/CapitalLeaseObligations" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/CapitalLeaseObligationsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasedAssetsLineItems" xlink:label="loc_us-gaap_CapitalLeasedAssetsLineItems_F8BB2CE0B37D9716F87ACF7EF6610359" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfCapitalLeasedAsssetsTable" xlink:label="loc_us-gaap_ScheduleOfCapitalLeasedAsssetsTable_3ECA364E055E13089805CF7EF65F16A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CapitalLeasedAssetsLineItems_F8BB2CE0B37D9716F87ACF7EF6610359" xlink:to="loc_us-gaap_ScheduleOfCapitalLeasedAsssetsTable_3ECA364E055E13089805CF7EF65F16A2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_832426CE1CF8C7ACFC95CF7EF65FD059" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalLeasedAsssetsTable_3ECA364E055E13089805CF7EF65F16A2" xlink:to="loc_srt_RangeAxis_832426CE1CF8C7ACFC95CF7EF65FD059" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_F936CD17D07844966484CF7EF660B264_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_832426CE1CF8C7ACFC95CF7EF65FD059" xlink:to="loc_srt_RangeMember_F936CD17D07844966484CF7EF660B264_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_F936CD17D07844966484CF7EF660B264" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_832426CE1CF8C7ACFC95CF7EF65FD059" xlink:to="loc_srt_RangeMember_F936CD17D07844966484CF7EF660B264" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_A4A2161F9A87DFBC5A63CF7EF660CB45" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_F936CD17D07844966484CF7EF660B264" xlink:to="loc_srt_MinimumMember_A4A2161F9A87DFBC5A63CF7EF660CB45" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_B1CCEC86F14CBC78224FCF7EF6600D5A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_F936CD17D07844966484CF7EF660B264" xlink:to="loc_srt_MaximumMember_B1CCEC86F14CBC78224FCF7EF6600D5A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasedAssetsLineItems_F8BB2CE0B37D9716F87ACF7EF6610359" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent_1776B8768B988FD7860DCF7EF6628619" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent_1776B8768B988FD7860DCF7EF6628619" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_D1C51E86A66B5686F57CCF7EF662343A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_D1C51E86A66B5686F57CCF7EF662343A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_A641DCB83096AE40D029CF7EF66279DE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_A641DCB83096AE40D029CF7EF66279DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears_764A8AF2DF031D2462ADCF7EF66224A4" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears_764A8AF2DF031D2462ADCF7EF66224A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears_2A75184BEDAD30335110CF7EF66201CE" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears_2A75184BEDAD30335110CF7EF66201CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_2FE2A27E488B0FB0B529CF7EF6635E45" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_2FE2A27E488B0FB0B529CF7EF6635E45" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments_B4AA10001AB7051BD9F1CF7EF66320D2" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments_B4AA10001AB7051BD9F1CF7EF66320D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments" xlink:label="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments_72970080FE55F3BC6D26CF7EF663DB1E" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments_72970080FE55F3BC6D26CF7EF663DB1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeaseObligationsCurrent" xlink:label="loc_us-gaap_CapitalLeaseObligationsCurrent_43F9CC7783A894CC7BFBCF7EF663488F" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeaseObligationsCurrent_43F9CC7783A894CC7BFBCF7EF663488F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeaseObligationsNoncurrent" xlink:label="loc_us-gaap_CapitalLeaseObligationsNoncurrent_C332179176237FE36CDBCF7EF664CEAB" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:to="loc_us-gaap_CapitalLeaseObligationsNoncurrent_C332179176237FE36CDBCF7EF664CEAB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesOfLesseeContingentRentalsBasisSpreadOnVariableRate" xlink:label="loc_us-gaap_CapitalLeasesOfLesseeContingentRentalsBasisSpreadOnVariableRate_10E58C11ADBFDD0EDF6FCF7EF664F562" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalLeasedAssetsLineItems_F8BB2CE0B37D9716F87ACF7EF6610359" xlink:to="loc_us-gaap_CapitalLeasesOfLesseeContingentRentalsBasisSpreadOnVariableRate_10E58C11ADBFDD0EDF6FCF7EF664F562" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/CapitalLeaseObligationsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/Commitments" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/CommitmentsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/CommitmentsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/ComparativeFigures" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/ConsolidatedBalanceSheets" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/ConsolidatedStatementsOfChangesInShareholdersEquity" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_53E3E96EDE74275E301F22E1E6AD7814" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_617699C871C2CC5C8A8422E1E6AA6223" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_53E3E96EDE74275E301F22E1E6AD7814" xlink:to="loc_us-gaap_StatementTable_617699C871C2CC5C8A8422E1E6AA6223" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_1F6395C9198CDA56D64F22E1E6AA668C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_617699C871C2CC5C8A8422E1E6AA6223" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_1F6395C9198CDA56D64F22E1E6AA668C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_42484DF517DAEEE1C3D922E1E6ABE1C4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_1F6395C9198CDA56D64F22E1E6AA668C" xlink:to="loc_us-gaap_TypeOfAdoptionMember_42484DF517DAEEE1C3D922E1E6ABE1C4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_42484DF517DAEEE1C3D922E1E6ABE1C4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_1F6395C9198CDA56D64F22E1E6AA668C" xlink:to="loc_us-gaap_TypeOfAdoptionMember_42484DF517DAEEE1C3D922E1E6ABE1C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountingStandardsUpdate201409Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201409Member_FFB308423EB923094F6B22E1E6AB3FE5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_42484DF517DAEEE1C3D922E1E6ABE1C4" xlink:to="loc_us-gaap_AccountingStandardsUpdate201409Member_FFB308423EB923094F6B22E1E6AB3FE5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_981BFA592B586D34C51D22E1E6ABB6E4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_617699C871C2CC5C8A8422E1E6AA6223" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_981BFA592B586D34C51D22E1E6ABB6E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_DD69878A25E97198669D22E1E6AC1ED3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_981BFA592B586D34C51D22E1E6ABB6E4" xlink:to="loc_us-gaap_EquityComponentDomain_DD69878A25E97198669D22E1E6AC1ED3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_DD69878A25E97198669D22E1E6AC1ED3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_981BFA592B586D34C51D22E1E6ABB6E4" xlink:to="loc_us-gaap_EquityComponentDomain_DD69878A25E97198669D22E1E6AC1ED3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ParentMember" xlink:label="loc_us-gaap_ParentMember_10EC82EC9A059A4159B522E1E6AC9E1C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_DD69878A25E97198669D22E1E6AC1ED3" xlink:to="loc_us-gaap_ParentMember_10EC82EC9A059A4159B522E1E6AC9E1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_7868F2601BAFAF9684BB22E1E6AC8042" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_10EC82EC9A059A4159B522E1E6AC9E1C" xlink:to="loc_us-gaap_CommonStockMember_7868F2601BAFAF9684BB22E1E6AC8042" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="loc_us-gaap_TreasuryStockMember_83C8CB00C3071FE5480422E1E6ACE20A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_10EC82EC9A059A4159B522E1E6AC9E1C" xlink:to="loc_us-gaap_TreasuryStockMember_83C8CB00C3071FE5480422E1E6ACE20A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_AABED90389B9448EEC7422E1E6ADFEF7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_10EC82EC9A059A4159B522E1E6AC9E1C" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_AABED90389B9448EEC7422E1E6ADFEF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_27D4C7E3CA0CAA9B8CDD22E1E6AD3462" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_10EC82EC9A059A4159B522E1E6AC9E1C" xlink:to="loc_us-gaap_RetainedEarningsMember_27D4C7E3CA0CAA9B8CDD22E1E6AD3462" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_267CE73B3089D3C9F71F22E1E6ADEBFF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_DD69878A25E97198669D22E1E6AC1ED3" xlink:to="loc_us-gaap_NoncontrollingInterestMember_267CE73B3089D3C9F71F22E1E6ADEBFF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_53E3E96EDE74275E301F22E1E6AD7814" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_B72BF5F9D69059BE463922E1E6AE0A3D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_B72BF5F9D69059BE463922E1E6AE0A3D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_8B07D68A08301CDE24FF22E1E6AEEA89" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_8B07D68A08301CDE24FF22E1E6AEEA89" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_17439203082DF07FD46022E1E6AEA246" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_us-gaap_ProfitLoss_17439203082DF07FD46022E1E6AEA246" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_B7EF85AEC6FA44A9664A22E1E6AE4332" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_B7EF85AEC6FA44A9664A22E1E6AE4332" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5C54397FE57219429B8F22E1E6AFD30F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5C54397FE57219429B8F22E1E6AFD30F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DividendsCommonStockCash" xlink:label="loc_us-gaap_DividendsCommonStockCash_815BCD01379018C013DE22E1E6AFDF16" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_us-gaap_DividendsCommonStockCash_815BCD01379018C013DE22E1E6AFDF16" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AdjustmentsToAdditionalPaidInCapitalRepurchaseOfSharesToSettleStockAwardPlan" xlink:label="loc_noa_AdjustmentsToAdditionalPaidInCapitalRepurchaseOfSharesToSettleStockAwardPlan_172AB8E69EDEB3A3370522E1E6AF449D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_noa_AdjustmentsToAdditionalPaidInCapitalRepurchaseOfSharesToSettleStockAwardPlan_172AB8E69EDEB3A3370522E1E6AF449D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_12A3675DDD9DED45F28322E1E6AF5C7A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_12A3675DDD9DED45F28322E1E6AF5C7A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_B05349D82613F89D0AB222E1E6AF7B9D" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_B05349D82613F89D0AB222E1E6AF7B9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination" xlink:label="loc_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_74448CAB308FC271496022E1E6AF4519" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5A85440AD8CDA6C32E3322E1E6AD4A97" xlink:to="loc_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_74448CAB308FC271496022E1E6AF4519" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/ConsolidatedStatementsOfChangesInStockholdersEquityParenthetical" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/ConsolidatedStatementsOfOperationsAndComprehensiveIncome" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/Contingencies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/DocumentAndEntityInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/EmployeeBenefitPlans" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/EmployeeBenefitPlansDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagement" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementAssetsHeldForSaleDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_055165AFD609058F9ACF0D1D07D3F583" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8E1E0D62CBF3549E18E10D1D07CFF55D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_055165AFD609058F9ACF0D1D07D3F583" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8E1E0D62CBF3549E18E10D1D07CFF55D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_69BA5477EE3EE4EEBF0F0D1D07CF2CB7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8E1E0D62CBF3549E18E10D1D07CFF55D" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_69BA5477EE3EE4EEBF0F0D1D07CF2CB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_A9750E963B6751FFD22F0D1D07D09F54_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_69BA5477EE3EE4EEBF0F0D1D07CF2CB7" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_A9750E963B6751FFD22F0D1D07D09F54_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_A9750E963B6751FFD22F0D1D07D09F54" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_69BA5477EE3EE4EEBF0F0D1D07CF2CB7" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_A9750E963B6751FFD22F0D1D07D09F54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_B7C4EB318973851FBA4F0D1D07D07013" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_A9750E963B6751FFD22F0D1D07D09F54" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_B7C4EB318973851FBA4F0D1D07D07013" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_A11CB9F013340BBDC10B0D1D07D05833" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8E1E0D62CBF3549E18E10D1D07CFF55D" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_A11CB9F013340BBDC10B0D1D07D05833" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7F5B474460C3D99B0D000D1D07D18223_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_A11CB9F013340BBDC10B0D1D07D05833" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7F5B474460C3D99B0D000D1D07D18223_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_74BA39F74B46A84676C70D1D07D002AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_A11CB9F013340BBDC10B0D1D07D05833" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_74BA39F74B46A84676C70D1D07D002AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7F5B474460C3D99B0D000D1D07D18223" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_74BA39F74B46A84676C70D1D07D002AE" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_7F5B474460C3D99B0D000D1D07D18223" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_724F333AEE7817AF80580D1D07D1B908" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_74BA39F74B46A84676C70D1D07D002AE" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_724F333AEE7817AF80580D1D07D1B908" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ChangeDuringPeriodFairValueDisclosureMember" xlink:label="loc_us-gaap_ChangeDuringPeriodFairValueDisclosureMember_9E133819F9A20C5F916E0D1D07D14CAA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_74BA39F74B46A84676C70D1D07D002AE" xlink:to="loc_us-gaap_ChangeDuringPeriodFairValueDisclosureMember_9E133819F9A20C5F916E0D1D07D14CAA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_0C4526476FF2A87757310D1D07D2F13F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8E1E0D62CBF3549E18E10D1D07CFF55D" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_0C4526476FF2A87757310D1D07D2F13F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2EB1FE8268AF60D161820D1D07D2CE84_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_0C4526476FF2A87757310D1D07D2F13F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2EB1FE8268AF60D161820D1D07D2CE84_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2EB1FE8268AF60D161820D1D07D2CE84" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_0C4526476FF2A87757310D1D07D2F13F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2EB1FE8268AF60D161820D1D07D2CE84" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_DB38B16BD8A5FDCEB6A00D1D07D2DFD0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2EB1FE8268AF60D161820D1D07D2CE84" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_DB38B16BD8A5FDCEB6A00D1D07D2DFD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure" xlink:label="loc_us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure_578D40852B16B7C35EDD0D1D07D3E9CF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_055165AFD609058F9ACF0D1D07D3F583" xlink:to="loc_us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure_578D40852B16B7C35EDD0D1D07D3E9CF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_D854B98303242B39241822DCF5A01291" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_23485C90DDFA7BC35EBF22DCF59B2937" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_D854B98303242B39241822DCF5A01291" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_23485C90DDFA7BC35EBF22DCF59B2937" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_5E4BA83CEC9B296B7EC322DCF59CE517" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_23485C90DDFA7BC35EBF22DCF59B2937" xlink:to="loc_us-gaap_DebtInstrumentAxis_5E4BA83CEC9B296B7EC322DCF59CE517" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_39976B944BBE81AF58AB22DCF59CB10E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_5E4BA83CEC9B296B7EC322DCF59CE517" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_39976B944BBE81AF58AB22DCF59CB10E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_39976B944BBE81AF58AB22DCF59CB10E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_5E4BA83CEC9B296B7EC322DCF59CE517" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_39976B944BBE81AF58AB22DCF59CB10E" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_EquipmentPromissoryNoteMember" xlink:label="loc_noa_EquipmentPromissoryNoteMember_4F3415F78960C94F5ABD22DCF59CE28A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_39976B944BBE81AF58AB22DCF59CB10E" xlink:to="loc_noa_EquipmentPromissoryNoteMember_4F3415F78960C94F5ABD22DCF59CE28A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D9C7A03872FBC44D878B22DCF59D9E83" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_23485C90DDFA7BC35EBF22DCF59B2937" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D9C7A03872FBC44D878B22DCF59D9E83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1255897AF9444D4733C122DCF59D91CC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D9C7A03872FBC44D878B22DCF59D9E83" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1255897AF9444D4733C122DCF59D91CC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1255897AF9444D4733C122DCF59D91CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_D9C7A03872FBC44D878B22DCF59D9E83" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1255897AF9444D4733C122DCF59D91CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_0046D836AAD4DBFAE2B322DCF59D9A6C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1255897AF9444D4733C122DCF59D91CC" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_0046D836AAD4DBFAE2B322DCF59D9A6C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_94B978EE7B38283E284E22DCF59EB636" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1255897AF9444D4733C122DCF59D91CC" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_94B978EE7B38283E284E22DCF59EB636" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_57837C83008E561DDB8E22DCF59E150B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_23485C90DDFA7BC35EBF22DCF59B2937" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_57837C83008E561DDB8E22DCF59E150B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_CC931BDD64A2948AF08D22DCF59EADF4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_57837C83008E561DDB8E22DCF59E150B" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_CC931BDD64A2948AF08D22DCF59EADF4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_440927635CAC671482A722DCF59E7531" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_57837C83008E561DDB8E22DCF59E150B" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_440927635CAC671482A722DCF59E7531" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_CC931BDD64A2948AF08D22DCF59EADF4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_440927635CAC671482A722DCF59E7531" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_CC931BDD64A2948AF08D22DCF59EADF4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_C59BDA532F67519305CB22DCF59EA5C8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_440927635CAC671482A722DCF59E7531" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_C59BDA532F67519305CB22DCF59EA5C8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_A7A7CA7D5C0CA070C25622DCF59F5726" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_440927635CAC671482A722DCF59E7531" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_A7A7CA7D5C0CA070C25622DCF59F5726" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_58FB205E11CD7C684B9822DCF59F9CB0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_23485C90DDFA7BC35EBF22DCF59B2937" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_58FB205E11CD7C684B9822DCF59F9CB0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_91D5D1EB900B7FEB319822DCF59FE489_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_58FB205E11CD7C684B9822DCF59F9CB0" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_91D5D1EB900B7FEB319822DCF59FE489_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_91D5D1EB900B7FEB319822DCF59FE489" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_58FB205E11CD7C684B9822DCF59F9CB0" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_91D5D1EB900B7FEB319822DCF59FE489" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_0422C1824B3E3CA2AD2722DCF59F6459" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_91D5D1EB900B7FEB319822DCF59FE489" xlink:to="loc_us-gaap_LineOfCreditMember_0422C1824B3E3CA2AD2722DCF59F6459" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgagesMember" xlink:label="loc_us-gaap_MortgagesMember_691CD8F2271D3F92852822DCF5A04204" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_91D5D1EB900B7FEB319822DCF59FE489" xlink:to="loc_us-gaap_MortgagesMember_691CD8F2271D3F92852822DCF5A04204" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_9FE7A863F3164D02B26E22DCF5A00DCE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_91D5D1EB900B7FEB319822DCF59FE489" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_9FE7A863F3164D02B26E22DCF5A00DCE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_413FE04428C87F879D5422DCF5A067F2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_D854B98303242B39241822DCF5A01291" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_413FE04428C87F879D5422DCF5A067F2" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CapitalLeaseObligationsFairValueDisclosure" xlink:label="loc_noa_CapitalLeaseObligationsFairValueDisclosure_00F050D8BDC57AB3F0E222DCF5A161A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_413FE04428C87F879D5422DCF5A067F2" xlink:to="loc_noa_CapitalLeaseObligationsFairValueDisclosure_00F050D8BDC57AB3F0E222DCF5A161A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentFairValue" xlink:label="loc_us-gaap_DebtInstrumentFairValue_210BD094E91AF89032E222DCF5A11791" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_413FE04428C87F879D5422DCF5A067F2" xlink:to="loc_us-gaap_DebtInstrumentFairValue_210BD094E91AF89032E222DCF5A11791" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementMaximumCreditExposureDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementRiskManagementDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_38BA0755E2C69815C2B6E9A094735437" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="loc_us-gaap_ConcentrationRiskTable_6C6DBDA0A0C5651109EAE9A0946D7788" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_38BA0755E2C69815C2B6E9A094735437" xlink:to="loc_us-gaap_ConcentrationRiskTable_6C6DBDA0A0C5651109EAE9A0946D7788" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_9A0C104AD3EE87D8C55AE9A0946D5EDC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_6C6DBDA0A0C5651109EAE9A0946D7788" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_9A0C104AD3EE87D8C55AE9A0946D5EDC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_7FC0D01F3F9E80661184E9A0946D0648_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_9A0C104AD3EE87D8C55AE9A0946D5EDC" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_7FC0D01F3F9E80661184E9A0946D0648_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_7FC0D01F3F9E80661184E9A0946D0648" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_9A0C104AD3EE87D8C55AE9A0946D5EDC" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_7FC0D01F3F9E80661184E9A0946D0648" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_52AD9C730C34DA1209F4E9A0946E376D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_7FC0D01F3F9E80661184E9A0946D0648" xlink:to="loc_us-gaap_LineOfCreditMember_52AD9C730C34DA1209F4E9A0946E376D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MajorCustomersAxis" xlink:label="loc_srt_MajorCustomersAxis_BCB16E0E9E6EB6139998E9A0946FFF9B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_6C6DBDA0A0C5651109EAE9A0946D7788" xlink:to="loc_srt_MajorCustomersAxis_BCB16E0E9E6EB6139998E9A0946FFF9B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_BC6223CDC398643E5E57E9A0946F74EA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_BCB16E0E9E6EB6139998E9A0946FFF9B" xlink:to="loc_srt_NameOfMajorCustomerDomain_BC6223CDC398643E5E57E9A0946F74EA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_BC6223CDC398643E5E57E9A0946F74EA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_BCB16E0E9E6EB6139998E9A0946FFF9B" xlink:to="loc_srt_NameOfMajorCustomerDomain_BC6223CDC398643E5E57E9A0946F74EA" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CustomerFMember" xlink:label="loc_noa_CustomerFMember_3DD31F4B7E50DBC61ADCE9A0946F9377" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_BC6223CDC398643E5E57E9A0946F74EA" xlink:to="loc_noa_CustomerFMember_3DD31F4B7E50DBC61ADCE9A0946F9377" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CustomerGMember" xlink:label="loc_noa_CustomerGMember_FD47FA51460F9D3DD08AE9A09470E086" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_BC6223CDC398643E5E57E9A0946F74EA" xlink:to="loc_noa_CustomerGMember_FD47FA51460F9D3DD08AE9A09470E086" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CustomerHMember" xlink:label="loc_noa_CustomerHMember_7430DF1258A20A7719D9E9A094702887" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_BC6223CDC398643E5E57E9A0946F74EA" xlink:to="loc_noa_CustomerHMember_7430DF1258A20A7719D9E9A094702887" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CustomerIMember" xlink:label="loc_noa_CustomerIMember_9F62A4251DCC43BDC1EAE9A0947032C3" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_BC6223CDC398643E5E57E9A0946F74EA" xlink:to="loc_noa_CustomerIMember_9F62A4251DCC43BDC1EAE9A0947032C3" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CustomerJMember" xlink:label="loc_noa_CustomerJMember_328E3A573D25ED76E669E9A094717E1F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_BC6223CDC398643E5E57E9A0946F74EA" xlink:to="loc_noa_CustomerJMember_328E3A573D25ED76E669E9A094717E1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_61D51CC7B86F61A51529E9A09471B78A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_6C6DBDA0A0C5651109EAE9A0946D7788" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_61D51CC7B86F61A51529E9A09471B78A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_1962CDF283197478AD0AE9A094710C51_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_61D51CC7B86F61A51529E9A09471B78A" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_1962CDF283197478AD0AE9A094710C51_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_1962CDF283197478AD0AE9A094710C51" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_61D51CC7B86F61A51529E9A09471B78A" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_1962CDF283197478AD0AE9A094710C51" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AccountsReceivableAndContractwithCustomerAssetMember" xlink:label="loc_noa_AccountsReceivableAndContractwithCustomerAssetMember_8AF44EDA415DAA610D7AE9A09472D9D9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_1962CDF283197478AD0AE9A094710C51" xlink:to="loc_noa_AccountsReceivableAndContractwithCustomerAssetMember_8AF44EDA415DAA610D7AE9A09472D9D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_B41B2F9E5A83180833B2E9A09472FB9D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_6C6DBDA0A0C5651109EAE9A0946D7788" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_B41B2F9E5A83180833B2E9A09472FB9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_5D0070228B22BB57BFEDE9A0947246E7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_B41B2F9E5A83180833B2E9A09472FB9D" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_5D0070228B22BB57BFEDE9A0947246E7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_5D0070228B22BB57BFEDE9A0947246E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_B41B2F9E5A83180833B2E9A09472FB9D" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_5D0070228B22BB57BFEDE9A0947246E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_21937BB7925E6B949085E9A0947365CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_5D0070228B22BB57BFEDE9A0947246E7" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_21937BB7925E6B949085E9A0947365CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtPercentageBearingVariableInterestAmount" xlink:label="loc_us-gaap_LongtermDebtPercentageBearingVariableInterestAmount_3BE5A606463D246E9F97E9A09474723F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_38BA0755E2C69815C2B6E9A094735437" xlink:to="loc_us-gaap_LongtermDebtPercentageBearingVariableInterestAmount_3BE5A606463D246E9F97E9A09474723F" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_InterestExpenseAdjustmentduetoInterestRateChange" xlink:label="loc_noa_InterestExpenseAdjustmentduetoInterestRateChange_A5DC14A756A5A0FBCCCCE9A09474B56D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_38BA0755E2C69815C2B6E9A094735437" xlink:to="loc_noa_InterestExpenseAdjustmentduetoInterestRateChange_A5DC14A756A5A0FBCCCCE9A09474B56D" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtInstrumentBasisSpreadonVariableRateAdjustment" xlink:label="loc_noa_DebtInstrumentBasisSpreadonVariableRateAdjustment_71B6BF40BEF7EC1176E2E9A094745E29" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_38BA0755E2C69815C2B6E9A094735437" xlink:to="loc_noa_DebtInstrumentBasisSpreadonVariableRateAdjustment_71B6BF40BEF7EC1176E2E9A094745E29" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_9C32620E1518D4A6B604E9A09475F84A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_38BA0755E2C69815C2B6E9A094735437" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_9C32620E1518D4A6B604E9A09475F84A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/FinancialInstrumentsAndRiskManagementTradeReceivablesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3E309CF354BBC367F1D39641290C254E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_08CB995C3775232018629641290A1B9D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3E309CF354BBC367F1D39641290C254E" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_08CB995C3775232018629641290A1B9D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_78BC66B3EB311BA7CCA79641290B5A0E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_08CB995C3775232018629641290A1B9D" xlink:to="loc_srt_RangeAxis_78BC66B3EB311BA7CCA79641290B5A0E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_FE3EE2ED377723C45F7A9641290BBCD0_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_78BC66B3EB311BA7CCA79641290B5A0E" xlink:to="loc_srt_RangeMember_FE3EE2ED377723C45F7A9641290BBCD0_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_FE3EE2ED377723C45F7A9641290BBCD0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_78BC66B3EB311BA7CCA79641290B5A0E" xlink:to="loc_srt_RangeMember_FE3EE2ED377723C45F7A9641290BBCD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_6956296E075FDE1ED7089641290C45EA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_FE3EE2ED377723C45F7A9641290BBCD0" xlink:to="loc_srt_MinimumMember_6956296E075FDE1ED7089641290C45EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_00B6A5820090C14D45F89641290C1937" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_FE3EE2ED377723C45F7A9641290BBCD0" xlink:to="loc_srt_MaximumMember_00B6A5820090C14D45F89641290C1937" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AccountsReceivableGeneralPaymentTerms" xlink:label="loc_noa_AccountsReceivableGeneralPaymentTerms_EA801FB13F6CBE5430DC9641290CF1C0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3E309CF354BBC367F1D39641290C254E" xlink:to="loc_noa_AccountsReceivableGeneralPaymentTerms_EA801FB13F6CBE5430DC9641290CF1C0" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AccountsReceivableCurrent" xlink:label="loc_noa_AccountsReceivableCurrent_1C6186C10DD540D2EDF39641290DA1B8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3E309CF354BBC367F1D39641290C254E" xlink:to="loc_noa_AccountsReceivableCurrent_1C6186C10DD540D2EDF39641290DA1B8" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AccountsReceivable1To30DaysPastDue" xlink:label="loc_noa_AccountsReceivable1To30DaysPastDue_913792B4083CB4FD75989641290D6AA0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3E309CF354BBC367F1D39641290C254E" xlink:to="loc_noa_AccountsReceivable1To30DaysPastDue_913792B4083CB4FD75989641290D6AA0" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AccountsReceivable31To60DaysPastDue" xlink:label="loc_noa_AccountsReceivable31To60DaysPastDue_7CC1BAF791B160CED0BC9641290D0D85" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3E309CF354BBC367F1D39641290C254E" xlink:to="loc_noa_AccountsReceivable31To60DaysPastDue_7CC1BAF791B160CED0BC9641290D0D85" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AccountsReceivableGreaterThan60DaysPastDue" xlink:label="loc_noa_AccountsReceivableGreaterThan60DaysPastDue_4035CE8D4293B98D6CC29641290EFAC0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3E309CF354BBC367F1D39641290C254E" xlink:to="loc_noa_AccountsReceivableGreaterThan60DaysPastDue_4035CE8D4293B98D6CC29641290EFAC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_6C5F550AACA6E3C8A8939641290E5494" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3E309CF354BBC367F1D39641290C254E" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_6C5F550AACA6E3C8A8939641290E5494" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/IncomeTaxes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/IncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/IncomeTaxesExpenseBenefitDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/IncomeTaxesExpirationOfNonCapitalLossesForIncomeTaxPurposesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLossCarryforwardsLineItems" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems_1DCCAADF0574CCAD4AC10CF2756102CA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLossCarryforwardsTable" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable_7AB52C41CC4F3D36DF670CF2755D975A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_1DCCAADF0574CCAD4AC10CF2756102CA" xlink:to="loc_us-gaap_OperatingLossCarryforwardsTable_7AB52C41CC4F3D36DF670CF2755D975A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="noa-20181231.xsd#noa_YearOfExpirationAxis" xlink:label="loc_noa_YearOfExpirationAxis_0F928C93ECB3D411EC730CF2755D2765" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_7AB52C41CC4F3D36DF670CF2755D975A" xlink:to="loc_noa_YearOfExpirationAxis_0F928C93ECB3D411EC730CF2755D2765" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_YearOfExpirationDomain" xlink:label="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_noa_YearOfExpirationAxis_0F928C93ECB3D411EC730CF2755D2765" xlink:to="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9_default" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_YearOfExpirationDomain" xlink:label="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_noa_YearOfExpirationAxis_0F928C93ECB3D411EC730CF2755D2765" xlink:to="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandTwentyFiveMember" xlink:label="loc_noa_TwoThousandTwentyFiveMember_9867805C753B3BC323F90CF2755E687C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandTwentyFiveMember_9867805C753B3BC323F90CF2755E687C" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandTwentySixMember" xlink:label="loc_noa_TwoThousandTwentySixMember_B49BB5895DDEFCA0C7100CF2755E2D5F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandTwentySixMember_B49BB5895DDEFCA0C7100CF2755E2D5F" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandTwentySevenMember" xlink:label="loc_noa_TwoThousandTwentySevenMember_3F742EE8B65A3021343B0CF2755F99AB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandTwentySevenMember_3F742EE8B65A3021343B0CF2755F99AB" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandThirtyOneMember" xlink:label="loc_noa_TwoThousandThirtyOneMember_E8DC06172B99C705B54B0CF2755F5218" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandThirtyOneMember_E8DC06172B99C705B54B0CF2755F5218" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandThirtyTwoMember" xlink:label="loc_noa_TwoThousandThirtyTwoMember_92678A4D049141AF21CE0CF275603CE2" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandThirtyTwoMember_92678A4D049141AF21CE0CF275603CE2" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandThirtyThreeMember" xlink:label="loc_noa_TwoThousandThirtyThreeMember_1597D21E56DC98EEB6D10CF275603C0D" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandThirtyThreeMember_1597D21E56DC98EEB6D10CF275603C0D" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandThirtyFourMember" xlink:label="loc_noa_TwoThousandThirtyFourMember_0A344425E9B1D1B1D70E0CF275605BBB" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandThirtyFourMember_0A344425E9B1D1B1D70E0CF275605BBB" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandThirtySixMember" xlink:label="loc_noa_TwoThousandThirtySixMember_EAE0C6192D00FE6BD8CB0CF27560F88A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandThirtySixMember_EAE0C6192D00FE6BD8CB0CF27560F88A" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandThirtySevenMember" xlink:label="loc_noa_TwoThousandThirtySevenMember_5E33BCF34376C73261D10CF275613892" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandThirtySevenMember_5E33BCF34376C73261D10CF275613892" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoThousandThirtyEightMember" xlink:label="loc_noa_TwoThousandThirtyEightMember_70220C0200340E4616E40CF27561681C" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_YearOfExpirationDomain_276790B43E31244784390CF2755ED4A9" xlink:to="loc_noa_TwoThousandThirtyEightMember_70220C0200340E4616E40CF27561681C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="loc_us-gaap_OperatingLossCarryforwards_79079BE89E50426B35E70CF27561B7D0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_1DCCAADF0574CCAD4AC10CF2756102CA" xlink:to="loc_us-gaap_OperatingLossCarryforwards_79079BE89E50426B35E70CF27561B7D0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/IncomeTaxesNarrativeDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/IncomeTaxesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InterestExpense" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InterestExpenseDetails" xlink:type="extended">
    <link:loc xlink:href="noa-20181231.xsd#noa_ScheduleOfInterestExpenseLineItems" xlink:label="loc_noa_ScheduleOfInterestExpenseLineItems_360BB5F990EB736A1624E76F28F19C3A" xlink:type="locator" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ScheduleOfInterestExpenseTable" xlink:label="loc_noa_ScheduleOfInterestExpenseTable_BD9F4A7E87EF2BAC217CE76F28EE491D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_noa_ScheduleOfInterestExpenseLineItems_360BB5F990EB736A1624E76F28F19C3A" xlink:to="loc_noa_ScheduleOfInterestExpenseTable_BD9F4A7E87EF2BAC217CE76F28EE491D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_7EFAA5A542E59B165E31E76F28EF7678" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_noa_ScheduleOfInterestExpenseTable_BD9F4A7E87EF2BAC217CE76F28EE491D" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_7EFAA5A542E59B165E31E76F28EF7678" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_D0DF82B71915DE061889E76F28EF528F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_7EFAA5A542E59B165E31E76F28EF7678" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_D0DF82B71915DE061889E76F28EF528F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_D0DF82B71915DE061889E76F28EF528F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_7EFAA5A542E59B165E31E76F28EF7678" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_D0DF82B71915DE061889E76F28EF528F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeaseObligationsMember" xlink:label="loc_us-gaap_CapitalLeaseObligationsMember_D24E36FCC5029BC57F16E76F28EFB598" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_D0DF82B71915DE061889E76F28EF528F" xlink:to="loc_us-gaap_CapitalLeaseObligationsMember_D24E36FCC5029BC57F16E76F28EFB598" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_6FAAE60B13A0A8787F5AE76F28EF3538" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_D0DF82B71915DE061889E76F28EF528F" xlink:to="loc_us-gaap_LineOfCreditMember_6FAAE60B13A0A8787F5AE76F28EF3538" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConvertibleSubordinatedDebtMember" xlink:label="loc_us-gaap_ConvertibleSubordinatedDebtMember_EAE56A77765BB3D81805E76F28F0C801" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_D0DF82B71915DE061889E76F28EF528F" xlink:to="loc_us-gaap_ConvertibleSubordinatedDebtMember_EAE56A77765BB3D81805E76F28F0C801" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_D43DA12125ED871C4AAFE82691EE3C5A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_D0DF82B71915DE061889E76F28EF528F" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_D43DA12125ED871C4AAFE82691EE3C5A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgagesMember" xlink:label="loc_us-gaap_MortgagesMember_937CFB412394BDFB7183E826B161CC59" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_D0DF82B71915DE061889E76F28EF528F" xlink:to="loc_us-gaap_MortgagesMember_937CFB412394BDFB7183E826B161CC59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseDebtExcludingAmortization" xlink:label="loc_us-gaap_InterestExpenseDebtExcludingAmortization_133753A0BDA96E0F631BE76F28F10E40" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleOfInterestExpenseLineItems_360BB5F990EB736A1624E76F28F19C3A" xlink:to="loc_us-gaap_InterestExpenseDebtExcludingAmortization_133753A0BDA96E0F631BE76F28F10E40" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_7ACC4A124F19B473DBE6E76F28F17AE1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleOfInterestExpenseLineItems_360BB5F990EB736A1624E76F28F19C3A" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_7ACC4A124F19B473DBE6E76F28F17AE1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseDebt" xlink:label="loc_us-gaap_InterestExpenseDebt_044C2642DD82F1DE27BEE76F28F1E103" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleOfInterestExpenseLineItems_360BB5F990EB736A1624E76F28F19C3A" xlink:to="loc_us-gaap_InterestExpenseDebt_044C2642DD82F1DE27BEE76F28F1E103" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeOther" xlink:label="loc_us-gaap_InterestIncomeOther_A6FC33BB9E5FE7E92D94E76F28F14100" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleOfInterestExpenseLineItems_360BB5F990EB736A1624E76F28F19C3A" xlink:to="loc_us-gaap_InterestIncomeOther_A6FC33BB9E5FE7E92D94E76F28F14100" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:label="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_C2FAF4BD94509896857EE76F28F21834" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_ScheduleOfInterestExpenseLineItems_360BB5F990EB736A1624E76F28F19C3A" xlink:to="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_C2FAF4BD94509896857EE76F28F21834" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InterestExpenseTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVentures" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesBalanceSheetsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableInterestEntityLineItems" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_BA48A95A71CA4EDB837C203714805C7D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_D85C8F4EA1429C7A7D0D2037147DE7FA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_BA48A95A71CA4EDB837C203714805C7D" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_D85C8F4EA1429C7A7D0D2037147DE7FA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_6B08025609C88CF84FD8203926D2D4AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_D85C8F4EA1429C7A7D0D2037147DE7FA" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_6B08025609C88CF84FD8203926D2D4AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_8DCC03EA924569FC8F2D203926D5D782_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_6B08025609C88CF84FD8203926D2D4AE" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_8DCC03EA924569FC8F2D203926D5D782_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_8DCC03EA924569FC8F2D203926D5D782" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_6B08025609C88CF84FD8203926D2D4AE" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_8DCC03EA924569FC8F2D203926D5D782" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DeneNorthSiteServicePartnershipMember" xlink:label="loc_noa_DeneNorthSiteServicePartnershipMember_77A45354C4F2DE40F263203E2163BACD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_8DCC03EA924569FC8F2D203926D5D782" xlink:to="loc_noa_DeneNorthSiteServicePartnershipMember_77A45354C4F2DE40F263203E2163BACD" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_MikisewNorthAmericanLimitedPartnershipMember" xlink:label="loc_noa_MikisewNorthAmericanLimitedPartnershipMember_1913F50677742F74F1C4203D753F4476" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_8DCC03EA924569FC8F2D203926D5D782" xlink:to="loc_noa_MikisewNorthAmericanLimitedPartnershipMember_1913F50677742F74F1C4203D753F4476" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis" xlink:label="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_E5743C754EE7F26615142037147D3E78" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_D85C8F4EA1429C7A7D0D2037147DE7FA" xlink:to="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_E5743C754EE7F26615142037147D3E78" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_0A596C993E2C278868262037147EAD45_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_E5743C754EE7F26615142037147D3E78" xlink:to="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_0A596C993E2C278868262037147EAD45_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_0A596C993E2C278868262037147EAD45" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_E5743C754EE7F26615142037147D3E78" xlink:to="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_0A596C993E2C278868262037147EAD45" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember" xlink:label="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_F6243CCCF4FABDD02EF22037147E4230" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_0A596C993E2C278868262037147EAD45" xlink:to="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_F6243CCCF4FABDD02EF22037147E4230" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableInterestEntityOwnershipPercentage" xlink:label="loc_us-gaap_VariableInterestEntityOwnershipPercentage_00E41895E7EE69B76FD720371480F547" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_BA48A95A71CA4EDB837C203714805C7D" xlink:to="loc_us-gaap_VariableInterestEntityOwnershipPercentage_00E41895E7EE69B76FD720371480F547" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesOwnershipPercentagesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableInterestEntityLineItems" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_60E54989903B8E2849642037148A0555" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_9D004AA4E72A72A2B9F7203714855434" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_60E54989903B8E2849642037148A0555" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_9D004AA4E72A72A2B9F7203714855434" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_631E4A6B8056CEC799F520371486B77F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_9D004AA4E72A72A2B9F7203714855434" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_631E4A6B8056CEC799F520371486B77F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_631E4A6B8056CEC799F520371486B77F" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_631E4A6B8056CEC799F520371486B77F" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_KivalliqServicesLtd.Member" xlink:label="loc_noa_KivalliqServicesLtd.Member_28E9E5A98B400541CC5C20371486433D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_KivalliqServicesLtd.Member_28E9E5A98B400541CC5C20371486433D" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_HRNContractingLtd.Member" xlink:label="loc_noa_HRNContractingLtd.Member_EA5BAB380DD7421E52E12037148744E7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_HRNContractingLtd.Member_EA5BAB380DD7421E52E12037148744E7" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AmikNunaForestryServicesJointVentureMember" xlink:label="loc_noa_AmikNunaForestryServicesJointVentureMember_BF4C5222AA0713AD937F20371487A636" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_AmikNunaForestryServicesJointVentureMember_BF4C5222AA0713AD937F20371487A636" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ArolandNunaJointVentureMember" xlink:label="loc_noa_ArolandNunaJointVentureMember_FC4849C7C3187D89FB5120371487D6E0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_ArolandNunaJointVentureMember_FC4849C7C3187D89FB5120371487D6E0" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_FondDuLacNunaMember" xlink:label="loc_noa_FondDuLacNunaMember_6AE2E1C0C42126DA8EA6203714879E3B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_FondDuLacNunaMember_6AE2E1C0C42126DA8EA6203714879E3B" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_MahiikanukNunaMember" xlink:label="loc_noa_MahiikanukNunaMember_269265F27C38E6D8EE4A20371487DEF4" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_MahiikanukNunaMember_269265F27C38E6D8EE4A20371487DEF4" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_MetNunaJointVentureMember" xlink:label="loc_noa_MetNunaJointVentureMember_B315CF9B7077EF49857320371487D3EB" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_MetNunaJointVentureMember_B315CF9B7077EF49857320371487D3EB" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaBauerJointVentureMember" xlink:label="loc_noa_NunaBauerJointVentureMember_B1DD6DF5536A401C552720371488A547" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_NunaBauerJointVentureMember_B1DD6DF5536A401C552720371488A547" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_EDCNunaContractingJointVentureMember" xlink:label="loc_noa_EDCNunaContractingJointVentureMember_C3368A79DA29FE413DDE203714881A5A" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_EDCNunaContractingJointVentureMember_C3368A79DA29FE413DDE203714881A5A" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AttawapiskatNunaJointVentureMember" xlink:label="loc_noa_AttawapiskatNunaJointVentureMember_6455F228DEC2D1C22D002037148820B7" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_AttawapiskatNunaJointVentureMember_6455F228DEC2D1C22D002037148820B7" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_WestarcDrillingBlastingServicesLtd.Member" xlink:label="loc_noa_WestarcDrillingBlastingServicesLtd.Member_8F10DC48E67D2424FB9F20371488BFF8" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_WestarcDrillingBlastingServicesLtd.Member_8F10DC48E67D2424FB9F20371488BFF8" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DetonChoNunaMember" xlink:label="loc_noa_DetonChoNunaMember_AE8B3FCBA0EB01BDCA5420371488FBEE" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_DetonChoNunaMember_AE8B3FCBA0EB01BDCA5420371488FBEE" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaDetonChoWinterRoadServicesMember" xlink:label="loc_noa_NunaDetonChoWinterRoadServicesMember_D6031255CF58E68287022040157075C7" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_NunaDetonChoWinterRoadServicesMember_D6031255CF58E68287022040157075C7" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaDetonChoContractingMember" xlink:label="loc_noa_NunaDetonChoContractingMember_EDD7EEC199E3DB151FBB204015A04024" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_18FDDBC882E3B930AB77203714861FEE" xlink:to="loc_noa_NunaDetonChoContractingMember_EDD7EEC199E3DB151FBB204015A04024" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis" xlink:label="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_044904DB2396173DDB7C20371489D6EF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_9D004AA4E72A72A2B9F7203714855434" xlink:to="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_044904DB2396173DDB7C20371489D6EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_9BB9710845324901CBFD20371489C1B8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_044904DB2396173DDB7C20371489D6EF" xlink:to="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_9BB9710845324901CBFD20371489C1B8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_9BB9710845324901CBFD20371489C1B8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_044904DB2396173DDB7C20371489D6EF" xlink:to="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_9BB9710845324901CBFD20371489C1B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember" xlink:label="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_169F91E617D5FBB33C82203714898B93" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_9BB9710845324901CBFD20371489C1B8" xlink:to="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_169F91E617D5FBB33C82203714898B93" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableInterestEntityPrimaryBeneficiaryMember" xlink:label="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_7BF827F9BFE98D7190232037148961A5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_9BB9710845324901CBFD20371489C1B8" xlink:to="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_7BF827F9BFE98D7190232037148961A5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_51A74788EB372D0585712037148A6A82" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_60E54989903B8E2849642037148A0555" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_51A74788EB372D0585712037148A6A82" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableInterestEntityOwnershipPercentage" xlink:label="loc_us-gaap_VariableInterestEntityOwnershipPercentage_13C9EEFFE2D811FA64572037148A9219" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_60E54989903B8E2849642037148A0555" xlink:to="loc_us-gaap_VariableInterestEntityOwnershipPercentage_13C9EEFFE2D811FA64572037148A9219" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesStatementsOfOperationsAndComprehensiveIncomeDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesSummaryOfMovementInInvestmentsInAffiliatesAndJointVenturesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/InvestmentsInAffiliatesAndJointVenturesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebt" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebtConvertibleDebentureDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_3763096E37C92B02F3C91D8E4DB07999" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_F7064BCA984CC60ACAAF1D8E4DAEBC6E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3763096E37C92B02F3C91D8E4DB07999" xlink:to="loc_us-gaap_DebtInstrumentTable_F7064BCA984CC60ACAAF1D8E4DAEBC6E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_7D6EE2942271A327E31A1D8E4DAF29AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_F7064BCA984CC60ACAAF1D8E4DAEBC6E" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_7D6EE2942271A327E31A1D8E4DAF29AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5A550FACFC61F0DC9C8C1D8E4DAFA3B6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_7D6EE2942271A327E31A1D8E4DAF29AE" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5A550FACFC61F0DC9C8C1D8E4DAFA3B6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5A550FACFC61F0DC9C8C1D8E4DAFA3B6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_7D6EE2942271A327E31A1D8E4DAF29AE" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5A550FACFC61F0DC9C8C1D8E4DAFA3B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConvertibleSubordinatedDebtMember" xlink:label="loc_us-gaap_ConvertibleSubordinatedDebtMember_336BA3483D4BC5ECE2A31D8E4DAFE3F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5A550FACFC61F0DC9C8C1D8E4DAFA3B6" xlink:to="loc_us-gaap_ConvertibleSubordinatedDebtMember_336BA3483D4BC5ECE2A31D8E4DAFE3F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_2A617A7E2F53C4BDBA471D8E4DB0B5B7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3763096E37C92B02F3C91D8E4DB07999" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_2A617A7E2F53C4BDBA471D8E4DB0B5B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_98028958C1CA3286D6FB1D8E4DB0E739" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3763096E37C92B02F3C91D8E4DB07999" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_98028958C1CA3286D6FB1D8E4DB0E739" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_C126EA7E88F2FF97B0431D8E4DB1EA57" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3763096E37C92B02F3C91D8E4DB07999" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_C126EA7E88F2FF97B0431D8E4DB1EA57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio1" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_EF28DD3DD313A360F2C71D8E4DB14F9B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3763096E37C92B02F3C91D8E4DB07999" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionRatio1_EF28DD3DD313A360F2C71D8E4DB14F9B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger" xlink:label="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_443AE18166BC147BB5B51D8E4DB168D4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3763096E37C92B02F3C91D8E4DB07999" xlink:to="loc_us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger_443AE18166BC147BB5B51D8E4DB168D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentRedemptionPricePercentage" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_76EB3E75071EB73D5B301D8E4DB24579" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3763096E37C92B02F3C91D8E4DB07999" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_76EB3E75071EB73D5B301D8E4DB24579" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebtCreditFacilityNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtCovenantPeriodAxis" xlink:label="loc_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:to="loc_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtCovenantPeriodDomain" xlink:label="loc_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:to="loc_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965_default" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtCovenantPeriodDomain" xlink:label="loc_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:to="loc_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtCovenantPeriodTrancheOneMember" xlink:label="loc_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:to="loc_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtCovenantPeriodTrancheTwoMember" xlink:label="loc_noa_DebtCovenantPeriodTrancheTwoMember_F893F78D9084CC68BE8F169678F4F75A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:to="loc_noa_DebtCovenantPeriodTrancheTwoMember_F893F78D9084CC68BE8F169678F4F75A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_8280E49B40E7257A4273169678F4A31A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:to="loc_us-gaap_DebtInstrumentAxis_8280E49B40E7257A4273169678F4A31A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_C62124CDF264B4AC3D6F169678F4223B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_8280E49B40E7257A4273169678F4A31A" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_C62124CDF264B4AC3D6F169678F4223B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_C62124CDF264B4AC3D6F169678F4223B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_8280E49B40E7257A4273169678F4A31A" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_C62124CDF264B4AC3D6F169678F4223B" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CreditFacilityMember" xlink:label="loc_noa_CreditFacilityMember_1C274069C95C19BE0AD0169678F5763C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_C62124CDF264B4AC3D6F169678F4223B" xlink:to="loc_noa_CreditFacilityMember_1C274069C95C19BE0AD0169678F5763C" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaCreditFacilityMember" xlink:label="loc_noa_NunaCreditFacilityMember_AF096AEE8901DB6394E4169678F52BD2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_C62124CDF264B4AC3D6F169678F4223B" xlink:to="loc_noa_NunaCreditFacilityMember_AF096AEE8901DB6394E4169678F52BD2" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaCreditFacilityOperatingLoanFacilityMember" xlink:label="loc_noa_NunaCreditFacilityOperatingLoanFacilityMember_B6E76C1EE016F9360369169678F5D5BB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_NunaCreditFacilityMember_AF096AEE8901DB6394E4169678F52BD2" xlink:to="loc_noa_NunaCreditFacilityOperatingLoanFacilityMember_B6E76C1EE016F9360369169678F5D5BB" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaCreditFacilityNonRevolvingReducingLoanFacilityMember" xlink:label="loc_noa_NunaCreditFacilityNonRevolvingReducingLoanFacilityMember_33F1102E6FCD4655B6BE169678F6F447" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_NunaCreditFacilityMember_AF096AEE8901DB6394E4169678F52BD2" xlink:to="loc_noa_NunaCreditFacilityNonRevolvingReducingLoanFacilityMember_33F1102E6FCD4655B6BE169678F6F447" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaCreditFacilityEquipmentFacilityMember" xlink:label="loc_noa_NunaCreditFacilityEquipmentFacilityMember_B9339CE727EBF80DD2A0169678F6B909" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_NunaCreditFacilityMember_AF096AEE8901DB6394E4169678F52BD2" xlink:to="loc_noa_NunaCreditFacilityEquipmentFacilityMember_B9339CE727EBF80DD2A0169678F6B909" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_483F1A1595BF8560D6D0169678F66AA8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:to="loc_us-gaap_CreditFacilityAxis_483F1A1595BF8560D6D0169678F66AA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_483F1A1595BF8560D6D0169678F66AA8" xlink:to="loc_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_483F1A1595BF8560D6D0169678F66AA8" xlink:to="loc_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_73593D7CC3B1A9AC1B58169678F756B2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_73593D7CC3B1A9AC1B58169678F756B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LetterOfCreditMember" xlink:label="loc_us-gaap_LetterOfCreditMember_C60D60A242D663D58460169678F7FECD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2" xlink:to="loc_us-gaap_LetterOfCreditMember_C60D60A242D663D58460169678F7FECD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_1C8FA7D70BCC575D9CEC169678F75257" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:to="loc_srt_RangeAxis_1C8FA7D70BCC575D9CEC169678F75257" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_C31D81D674E0439FC917169678F799E9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_1C8FA7D70BCC575D9CEC169678F75257" xlink:to="loc_srt_RangeMember_C31D81D674E0439FC917169678F799E9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_C31D81D674E0439FC917169678F799E9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_1C8FA7D70BCC575D9CEC169678F75257" xlink:to="loc_srt_RangeMember_C31D81D674E0439FC917169678F799E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_D82AF642E51D8CA96FA8169678F7AC8B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_C31D81D674E0439FC917169678F799E9" xlink:to="loc_srt_MinimumMember_D82AF642E51D8CA96FA8169678F7AC8B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_0C2D4AED5A1C9DD6619F169678F890E2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_C31D81D674E0439FC917169678F799E9" xlink:to="loc_srt_MaximumMember_0C2D4AED5A1C9DD6619F169678F890E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_A032A74E2FB3D1C0D41D169678F81F8F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_A032A74E2FB3D1C0D41D169678F81F8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_771EF15FB97E1D464095169678F89F3A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_A032A74E2FB3D1C0D41D169678F81F8F" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_771EF15FB97E1D464095169678F89F3A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_771EF15FB97E1D464095169678F89F3A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_A032A74E2FB3D1C0D41D169678F81F8F" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_771EF15FB97E1D464095169678F89F3A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_5F102729BC6E9C7A6B7D169678F9C1F8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_771EF15FB97E1D464095169678F89F3A" xlink:to="loc_us-gaap_LineOfCreditMember_5F102729BC6E9C7A6B7D169678F9C1F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_4D86CE73FA6F7EC2A275169678F9DD8B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_771EF15FB97E1D464095169678F89F3A" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_4D86CE73FA6F7EC2A275169678F9DD8B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_A2F5F263D3FD72C0F972169678F9D6E5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_A2F5F263D3FD72C0F972169678F9D6E5" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_LineofCreditFacilityAccordionFeatureIncreaseLimit" xlink:label="loc_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity" xlink:label="loc_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit" xlink:label="loc_noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit_8DFDB5C16528CFBD8002169678FAC710" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit_8DFDB5C16528CFBD8002169678FAC710" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_00B48D9790F311EF5D97169678FA0841" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_00B48D9790F311EF5D97169678FA0841" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtInstrumentNumberofDebtCovenants" xlink:label="loc_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_RatioOfIndebtednessToNetCapitalRentalRevenue" xlink:label="loc_noa_RatioOfIndebtednessToNetCapitalRentalRevenue_D1D7024B60652312CB79169678FB4872" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_noa_RatioOfIndebtednessToNetCapitalRentalRevenue_D1D7024B60652312CB79169678FB4872" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_766808FA00E6B572F437169678FBC172" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_766808FA00E6B572F437169678FBC172" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RatioOfIndebtednessToNetCapital1" xlink:label="loc_us-gaap_RatioOfIndebtednessToNetCapital1_5B6615977C9579D2DD6C169678FB719F" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_us-gaap_RatioOfIndebtednessToNetCapital1_5B6615977C9579D2DD6C169678FB719F" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_RatioOfIndebtednessToNetCapitalStepUpMultipleForFollowingFourQuarters" xlink:label="loc_noa_RatioOfIndebtednessToNetCapitalStepUpMultipleForFollowingFourQuarters_9C9B12F5AD02C7CD4B4F169678FB7A36" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_noa_RatioOfIndebtednessToNetCapitalStepUpMultipleForFollowingFourQuarters_9C9B12F5AD02C7CD4B4F169678FB7A36" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtInstrumentCovenantTermsFixedChargeRatio" xlink:label="loc_noa_DebtInstrumentCovenantTermsFixedChargeRatio_B733A288F8577707CD08169678FBA3A3" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_noa_DebtInstrumentCovenantTermsFixedChargeRatio_B733A288F8577707CD08169678FBA3A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_E6CCB8A75AD5C53C0A86169678FC2629" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_E6CCB8A75AD5C53C0A86169678FC2629" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_0D1823BA390BB7E30CC3169678FCC258" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_0D1823BA390BB7E30CC3169678FCC258" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="loc_us-gaap_DebtInstrumentTerm_5BA0BE85FA0CCA7CB89F169678FD62D7" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="loc_us-gaap_DebtInstrumentTerm_5BA0BE85FA0CCA7CB89F169678FD62D7" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebtDeferredFinancingDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_DF6318B95F993ACF484E182AD46BA12E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_277F743FB9CAE62B91BA182AD469426E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_DF6318B95F993ACF484E182AD46BA12E" xlink:to="loc_us-gaap_DebtInstrumentTable_277F743FB9CAE62B91BA182AD469426E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_EF39F51504B2851AB9DC182AD46AE194" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_277F743FB9CAE62B91BA182AD469426E" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_EF39F51504B2851AB9DC182AD46AE194" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_FE25DDD412F9EBBB836E182AD46A9CF7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_EF39F51504B2851AB9DC182AD46AE194" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_FE25DDD412F9EBBB836E182AD46A9CF7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_FE25DDD412F9EBBB836E182AD46A9CF7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_EF39F51504B2851AB9DC182AD46AE194" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_FE25DDD412F9EBBB836E182AD46A9CF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgagesMember" xlink:label="loc_us-gaap_MortgagesMember_2627A442A07038EA8EFA182AD46B37A1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_FE25DDD412F9EBBB836E182AD46A9CF7" xlink:to="loc_us-gaap_MortgagesMember_2627A442A07038EA8EFA182AD46B37A1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredFinanceCostsGross" xlink:label="loc_us-gaap_DeferredFinanceCostsGross_484D2FB62BA2FB9C287D182AD46C61E3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_DF6318B95F993ACF484E182AD46BA12E" xlink:to="loc_us-gaap_DeferredFinanceCostsGross_484D2FB62BA2FB9C287D182AD46C61E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedAmortizationDeferredFinanceCosts" xlink:label="loc_us-gaap_AccumulatedAmortizationDeferredFinanceCosts_FAD2EB8F23EF80188BF1182AD46C5C8B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_DF6318B95F993ACF484E182AD46BA12E" xlink:to="loc_us-gaap_AccumulatedAmortizationDeferredFinanceCosts_FAD2EB8F23EF80188BF1182AD46C5C8B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredFinanceCostsNet" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_5CDA8363B2823C131E27182AD46CCCC4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_DF6318B95F993ACF484E182AD46BA12E" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_5CDA8363B2823C131E27182AD46CCCC4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_5E914714839D7B902EFB182AD46DC91C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_DF6318B95F993ACF484E182AD46BA12E" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_5E914714839D7B902EFB182AD46DC91C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_E7F11422D5B8A27429DC182AD46DCB74" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_DF6318B95F993ACF484E182AD46BA12E" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_E7F11422D5B8A27429DC182AD46DCB74" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebtMortgageDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_F9741694E81A455F44091D8FDAF103EA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_439AF60077BE47E801B31D8FDAF042BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F9741694E81A455F44091D8FDAF103EA" xlink:to="loc_us-gaap_DebtInstrumentTable_439AF60077BE47E801B31D8FDAF042BE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_4E650C8E103F2D0C041D1D8FDAF01962" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_439AF60077BE47E801B31D8FDAF042BE" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_4E650C8E103F2D0C041D1D8FDAF01962" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_97F9BD878C9DD679F3EC1D8FDAF1CA76_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_4E650C8E103F2D0C041D1D8FDAF01962" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_97F9BD878C9DD679F3EC1D8FDAF1CA76_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_97F9BD878C9DD679F3EC1D8FDAF1CA76" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_4E650C8E103F2D0C041D1D8FDAF01962" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_97F9BD878C9DD679F3EC1D8FDAF1CA76" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgagesMember" xlink:label="loc_us-gaap_MortgagesMember_7657FFE7CF1B00D8C2B71D8FDAF15B7B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_97F9BD878C9DD679F3EC1D8FDAF1CA76" xlink:to="loc_us-gaap_MortgagesMember_7657FFE7CF1B00D8C2B71D8FDAF15B7B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="loc_us-gaap_DebtInstrumentTerm_44EEC6ACEB41983C11971D8FDAF1A7B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F9741694E81A455F44091D8FDAF103EA" xlink:to="loc_us-gaap_DebtInstrumentTerm_44EEC6ACEB41983C11971D8FDAF1A7B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_595EC67D4B68D722329E1D8FDAF272E2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F9741694E81A455F44091D8FDAF103EA" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_595EC67D4B68D722329E1D8FDAF272E2" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtInstrumentInterestRateStatedPercentagePeriod" xlink:label="loc_noa_DebtInstrumentInterestRateStatedPercentagePeriod_C2E1FEE1FBF4A9AC2FD81D8FDAF22D57" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F9741694E81A455F44091D8FDAF103EA" xlink:to="loc_noa_DebtInstrumentInterestRateStatedPercentagePeriod_C2E1FEE1FBF4A9AC2FD81D8FDAF22D57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_A638F8A73590AFC3F8131D8FDAF2403B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F9741694E81A455F44091D8FDAF103EA" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_A638F8A73590AFC3F8131D8FDAF2403B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_39EB866548EDC5BD5B371D8FDAF2A710" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F9741694E81A455F44091D8FDAF103EA" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_39EB866548EDC5BD5B371D8FDAF2A710" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebtPromissoryNotesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_55B29973278772EC003322DA88F5BBF0" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_04939A9289944FAC8F5D22DA88F3FCC2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_55B29973278772EC003322DA88F5BBF0" xlink:to="loc_us-gaap_DebtInstrumentTable_04939A9289944FAC8F5D22DA88F3FCC2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_C787654766B7F4B7CA3E22DA88F33AAF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_04939A9289944FAC8F5D22DA88F3FCC2" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_C787654766B7F4B7CA3E22DA88F33AAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_11389FE5A4190DD4F95C22DA88F36C5E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_C787654766B7F4B7CA3E22DA88F33AAF" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_11389FE5A4190DD4F95C22DA88F36C5E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_11389FE5A4190DD4F95C22DA88F36C5E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_C787654766B7F4B7CA3E22DA88F33AAF" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_11389FE5A4190DD4F95C22DA88F36C5E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_4F10BE1E9C9AB74E4B2522DA88F43AA8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_11389FE5A4190DD4F95C22DA88F36C5E" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_4F10BE1E9C9AB74E4B2522DA88F43AA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_FD87C25854143CEBA78122DA88F519B9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_55B29973278772EC003322DA88F5BBF0" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_FD87C25854143CEBA78122DA88F519B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_A17019CA89408BEC3DB522DA88F5B0F2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_55B29973278772EC003322DA88F5BBF0" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_A17019CA89408BEC3DB522DA88F5B0F2" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebtScheduleOfCreditFacilitiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_21AC3A5D771F1CCFD14DDD0D589BF336" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_53C20240B2777258DDC7DD0D589697FD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_21AC3A5D771F1CCFD14DDD0D589BF336" xlink:to="loc_us-gaap_DebtInstrumentTable_53C20240B2777258DDC7DD0D589697FD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_F5660FC1777BC77FF607DD0D58975F0C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_53C20240B2777258DDC7DD0D589697FD" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_F5660FC1777BC77FF607DD0D58975F0C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_A07720B2FB6F31ED9DB5DD0D58983CE6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_F5660FC1777BC77FF607DD0D58975F0C" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_A07720B2FB6F31ED9DB5DD0D58983CE6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_A07720B2FB6F31ED9DB5DD0D58983CE6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_F5660FC1777BC77FF607DD0D58975F0C" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_A07720B2FB6F31ED9DB5DD0D58983CE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_F3BA5372E252503ED653DD286B16C45A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_A07720B2FB6F31ED9DB5DD0D58983CE6" xlink:to="loc_us-gaap_LineOfCreditMember_F3BA5372E252503ED653DD286B16C45A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_C961D8878F79886821A4DD0D589A131E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_53C20240B2777258DDC7DD0D589697FD" xlink:to="loc_us-gaap_DebtInstrumentAxis_C961D8878F79886821A4DD0D589A131E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4538704971F66316E145DD0D589A763B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_C961D8878F79886821A4DD0D589A131E" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4538704971F66316E145DD0D589A763B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4538704971F66316E145DD0D589A763B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_C961D8878F79886821A4DD0D589A131E" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4538704971F66316E145DD0D589A763B" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CreditFacilityMember" xlink:label="loc_noa_CreditFacilityMember_77B1F567BA2D765E6618DD0D589A60F3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_4538704971F66316E145DD0D589A763B" xlink:to="loc_noa_CreditFacilityMember_77B1F567BA2D765E6618DD0D589A60F3" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaCreditFacilityMember" xlink:label="loc_noa_NunaCreditFacilityMember_C64226F232D7B45B4C23DD359AFAF45B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_4538704971F66316E145DD0D589A763B" xlink:to="loc_noa_NunaCreditFacilityMember_C64226F232D7B45B4C23DD359AFAF45B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_6EDDB69491A7C2EC51F7DD286733CCAF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_21AC3A5D771F1CCFD14DDD0D589BF336" xlink:to="loc_us-gaap_LongTermDebtCurrent_6EDDB69491A7C2EC51F7DD286733CCAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_ECEA87486A6BE6FC75CDDD3AF7F0B832" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_21AC3A5D771F1CCFD14DDD0D589BF336" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_ECEA87486A6BE6FC75CDDD3AF7F0B832" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_72F4605FD136397409D6DD2F56CA7471" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_21AC3A5D771F1CCFD14DDD0D589BF336" xlink:to="loc_us-gaap_LongTermDebt_72F4605FD136397409D6DD2F56CA7471" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebtScheduleOfLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_CE6E952F7E97A749D5E422DA7CF4FB8F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_9EFA935302CA875BF3B522DA7CF15DDB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_CE6E952F7E97A749D5E422DA7CF4FB8F" xlink:to="loc_us-gaap_DebtInstrumentTable_9EFA935302CA875BF3B522DA7CF15DDB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_F52C0A57AD80F9A355B722DA7CF2D989" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_9EFA935302CA875BF3B522DA7CF15DDB" xlink:to="loc_us-gaap_DebtInstrumentAxis_F52C0A57AD80F9A355B722DA7CF2D989" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0E6624ED1835D0C54D8322DA7CF270B4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_F52C0A57AD80F9A355B722DA7CF2D989" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0E6624ED1835D0C54D8322DA7CF270B4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0E6624ED1835D0C54D8322DA7CF270B4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_F52C0A57AD80F9A355B722DA7CF2D989" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0E6624ED1835D0C54D8322DA7CF270B4" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CreditFacilityMember" xlink:label="loc_noa_CreditFacilityMember_360A917880AC91B0605522DA7CF2D1A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0E6624ED1835D0C54D8322DA7CF270B4" xlink:to="loc_noa_CreditFacilityMember_360A917880AC91B0605522DA7CF2D1A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_FB844BF08FB1FD058EDD22DA7CF2C4ED" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_9EFA935302CA875BF3B522DA7CF15DDB" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_FB844BF08FB1FD058EDD22DA7CF2C4ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_93F3D34606DB1FF4BF0B22DA7CF29ABF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_FB844BF08FB1FD058EDD22DA7CF2C4ED" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_93F3D34606DB1FF4BF0B22DA7CF29ABF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_93F3D34606DB1FF4BF0B22DA7CF29ABF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_FB844BF08FB1FD058EDD22DA7CF2C4ED" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_93F3D34606DB1FF4BF0B22DA7CF29ABF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_AC9C09BB9A2C6ABB0A6322DA7CF3E271" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_93F3D34606DB1FF4BF0B22DA7CF29ABF" xlink:to="loc_us-gaap_LineOfCreditMember_AC9C09BB9A2C6ABB0A6322DA7CF3E271" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgagesMember" xlink:label="loc_us-gaap_MortgagesMember_C1F5144B7EC94D67DA7322DA7CF3C87F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_93F3D34606DB1FF4BF0B22DA7CF29ABF" xlink:to="loc_us-gaap_MortgagesMember_C1F5144B7EC94D67DA7322DA7CF3C87F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConvertibleSubordinatedDebtMember" xlink:label="loc_us-gaap_ConvertibleSubordinatedDebtMember_BC1FEB348399F044D3FE22DA7CF35FA8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_93F3D34606DB1FF4BF0B22DA7CF29ABF" xlink:to="loc_us-gaap_ConvertibleSubordinatedDebtMember_BC1FEB348399F044D3FE22DA7CF35FA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_54C6C71983B57F24DD8122DA7CF3A03F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_93F3D34606DB1FF4BF0B22DA7CF29ABF" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_54C6C71983B57F24DD8122DA7CF3A03F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtCurrentAbstract" xlink:label="loc_us-gaap_LongTermDebtCurrentAbstract_7622A429EE3BD827351B22DA7CF4F953" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_CE6E952F7E97A749D5E422DA7CF4FB8F" xlink:to="loc_us-gaap_LongTermDebtCurrentAbstract_7622A429EE3BD827351B22DA7CF4F953" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_8567EC15CF482B7D003622DA7CF49695" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtCurrentAbstract_7622A429EE3BD827351B22DA7CF4F953" xlink:to="loc_us-gaap_LongTermDebtCurrent_8567EC15CF482B7D003622DA7CF49695" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtNoncurrentAbstract" xlink:label="loc_us-gaap_LongTermDebtNoncurrentAbstract_18C089C7BED0A35F489122DA7CF492B3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_CE6E952F7E97A749D5E422DA7CF4FB8F" xlink:to="loc_us-gaap_LongTermDebtNoncurrentAbstract_18C089C7BED0A35F489122DA7CF492B3" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_LongtermDebtGrossNoncurrent" xlink:label="loc_noa_LongtermDebtGrossNoncurrent_A1CAEBD15A4EF85A1C9122DA7CF48354" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtNoncurrentAbstract_18C089C7BED0A35F489122DA7CF492B3" xlink:to="loc_noa_LongtermDebtGrossNoncurrent_A1CAEBD15A4EF85A1C9122DA7CF48354" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredFinanceCostsNoncurrentNet" xlink:label="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_F94C54E20BC413837C0922DA7CF5E70F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtNoncurrentAbstract_18C089C7BED0A35F489122DA7CF492B3" xlink:to="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_F94C54E20BC413837C0922DA7CF5E70F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_37E289011A990712214F22DA7CF7BE72" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtNoncurrentAbstract_18C089C7BED0A35F489122DA7CF492B3" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_37E289011A990712214F22DA7CF7BE72" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtByMaturityAbstract" xlink:label="loc_us-gaap_LongTermDebtByMaturityAbstract_5BEA232DA8E158B2666C22DA7CF779DE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_CE6E952F7E97A749D5E422DA7CF4FB8F" xlink:to="loc_us-gaap_LongTermDebtByMaturityAbstract_5BEA232DA8E158B2666C22DA7CF779DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_1A8AB799EB02150FE7E822DA7CF8A671" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_5BEA232DA8E158B2666C22DA7CF779DE" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_1A8AB799EB02150FE7E822DA7CF8A671" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_40D6CA14F114C39B0EB622DA7CF82D57" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_5BEA232DA8E158B2666C22DA7CF779DE" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_40D6CA14F114C39B0EB622DA7CF82D57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_EF4053E42A9EAA1A840222DA7CF86B87" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_5BEA232DA8E158B2666C22DA7CF779DE" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_EF4053E42A9EAA1A840222DA7CF86B87" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_F96E2C7FAB5F577F2C8B22DA7CF8C4E8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_5BEA232DA8E158B2666C22DA7CF779DE" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_F96E2C7FAB5F577F2C8B22DA7CF8C4E8" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_LongtermDebtMaturitiesRepaymentsOfPrincipalInYearFiveAndThereafter" xlink:label="loc_noa_LongtermDebtMaturitiesRepaymentsOfPrincipalInYearFiveAndThereafter_8F0776A9BBF963CDD00222DA7CF9B940" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_5BEA232DA8E158B2666C22DA7CF779DE" xlink:to="loc_noa_LongtermDebtMaturitiesRepaymentsOfPrincipalInYearFiveAndThereafter_8F0776A9BBF963CDD00222DA7CF9B940" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebtScheduleOfPromissoryNotesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_51D605F28D93911F603222DA86B728A4" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_9CDF5084E9C95CB8977D22DA86B54604" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51D605F28D93911F603222DA86B728A4" xlink:to="loc_us-gaap_DebtInstrumentTable_9CDF5084E9C95CB8977D22DA86B54604" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_3147823A3C9579856C6E22DA86B56055" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_9CDF5084E9C95CB8977D22DA86B54604" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_3147823A3C9579856C6E22DA86B56055" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_78660C69A89CCBECAF5F22DA86B59FC7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_3147823A3C9579856C6E22DA86B56055" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_78660C69A89CCBECAF5F22DA86B59FC7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_78660C69A89CCBECAF5F22DA86B59FC7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_3147823A3C9579856C6E22DA86B56055" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_78660C69A89CCBECAF5F22DA86B59FC7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_2B75F45F7EF98F253B4922DA86B614E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_78660C69A89CCBECAF5F22DA86B59FC7" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_2B75F45F7EF98F253B4922DA86B614E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_CAAA5AD4B52B684CE89822DA86B7A3A6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51D605F28D93911F603222DA86B728A4" xlink:to="loc_us-gaap_LongTermDebtCurrent_CAAA5AD4B52B684CE89822DA86B7A3A6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_82A99B9DB3C00897771922DA86B70074" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51D605F28D93911F603222DA86B728A4" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_82A99B9DB3C00897771922DA86B70074" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/LongTermDebtTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/NatureOfOperations" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherAssets" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherAssetsDeferredFinancingCostsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_59A52A05C9B6216F8BD20CF275D6C1E3" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_C8B6BA0A0D0DA5CDD3500CF275D5D0D0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59A52A05C9B6216F8BD20CF275D6C1E3" xlink:to="loc_us-gaap_DebtInstrumentTable_C8B6BA0A0D0DA5CDD3500CF275D5D0D0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_628564F6C5FF6BB8D6BB0CF275D5DBED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_C8B6BA0A0D0DA5CDD3500CF275D5D0D0" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_628564F6C5FF6BB8D6BB0CF275D5DBED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_461687B49CD9D8075B580CF275D52C88_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_628564F6C5FF6BB8D6BB0CF275D5DBED" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_461687B49CD9D8075B580CF275D52C88_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_461687B49CD9D8075B580CF275D52C88" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_628564F6C5FF6BB8D6BB0CF275D5DBED" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_461687B49CD9D8075B580CF275D52C88" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_5FC6E676A823C8C198F80CF275D67481" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_461687B49CD9D8075B580CF275D52C88" xlink:to="loc_us-gaap_LineOfCreditMember_5FC6E676A823C8C198F80CF275D67481" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_A6BCD212F6ED92D07DE70CF275D6220D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditMember_5FC6E676A823C8C198F80CF275D67481" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_A6BCD212F6ED92D07DE70CF275D6220D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredFinanceCostsNetAbstract" xlink:label="loc_us-gaap_DeferredFinanceCostsNetAbstract_C287F3AD49DFE825184A0CF275D72ED5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59A52A05C9B6216F8BD20CF275D6C1E3" xlink:to="loc_us-gaap_DeferredFinanceCostsNetAbstract_C287F3AD49DFE825184A0CF275D72ED5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross" xlink:label="loc_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross_4B2206843A80643800E30CF275D7BD4C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredFinanceCostsNetAbstract_C287F3AD49DFE825184A0CF275D72ED5" xlink:to="loc_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsGross_4B2206843A80643800E30CF275D7BD4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedAmortizationOfDebtIssuanceCostsLineOfCreditArrangements" xlink:label="loc_us-gaap_AccumulatedAmortizationOfDebtIssuanceCostsLineOfCreditArrangements_1B6CEDF797D34F59412B0CF275D88D99" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredFinanceCostsNetAbstract_C287F3AD49DFE825184A0CF275D72ED5" xlink:to="loc_us-gaap_AccumulatedAmortizationOfDebtIssuanceCostsLineOfCreditArrangements_1B6CEDF797D34F59412B0CF275D88D99" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtIssuanceCostsLineOfCreditArrangementsNet" xlink:label="loc_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsNet_F1354AFB997F2369BC6E0CF275D8BCB2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredFinanceCostsNetAbstract_C287F3AD49DFE825184A0CF275D72ED5" xlink:to="loc_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsNet_F1354AFB997F2369BC6E0CF275D8BCB2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_FBBC33E277719D3C20980CF275D81496" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59A52A05C9B6216F8BD20CF275D6C1E3" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_FBBC33E277719D3C20980CF275D81496" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_DA2E2071226DFEA546700CF275D8D192" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_59A52A05C9B6216F8BD20CF275D6C1E3" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_DA2E2071226DFEA546700CF275D8D192" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherAssetsDeferredLeaseInducementsAssetDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherAssetsIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_829A78DFD3B114C50D4817307D2817A9" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_60558145F60146D93AA817307D26A0B9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_829A78DFD3B114C50D4817307D2817A9" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_60558145F60146D93AA817307D26A0B9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_96D0347DA3F279DA1CB817307D26F4F6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_60558145F60146D93AA817307D26A0B9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_96D0347DA3F279DA1CB817307D26F4F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D4CDB8748582F2DCD76C17307D27C2AA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_96D0347DA3F279DA1CB817307D26F4F6" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D4CDB8748582F2DCD76C17307D27C2AA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D4CDB8748582F2DCD76C17307D27C2AA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_96D0347DA3F279DA1CB817307D26F4F6" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D4CDB8748582F2DCD76C17307D27C2AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:label="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_033BAB2367715240E18E17307D273004" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D4CDB8748582F2DCD76C17307D27C2AA" xlink:to="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_033BAB2367715240E18E17307D273004" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherIntangibleAssetsMember" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_5B5DB09A533E931C3D1717307D27A09E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_D4CDB8748582F2DCD76C17307D27C2AA" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_5B5DB09A533E931C3D1717307D27A09E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_E8411704EA23926A3E5717307D28EE13" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_829A78DFD3B114C50D4817307D2817A9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_E8411704EA23926A3E5717307D28EE13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_58EF40299BA9912A986517307D28E779" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_829A78DFD3B114C50D4817307D2817A9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_58EF40299BA9912A986517307D28E779" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_21951E6E56B9C90DDB3717307D2858E4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_829A78DFD3B114C50D4817307D2817A9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_21951E6E56B9C90DDB3717307D2858E4" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_FiniteLivedIntangibleAssetsDisposals" xlink:label="loc_noa_FiniteLivedIntangibleAssetsDisposals_754AE03B62BF6C5BEB4017307D29BA72" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_829A78DFD3B114C50D4817307D2817A9" xlink:to="loc_noa_FiniteLivedIntangibleAssetsDisposals_754AE03B62BF6C5BEB4017307D29BA72" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherAssetsScheduleOfOtherAssetsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherAssetsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherInformationNonCashDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherInformationOtherInformationSupplementalCashFlowInformationDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherInformationTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherLongTermObligations" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherLongTermObligationsOtherLiabilitiesAndObligationsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherLongTermObligationsScheduleOfOtherLongTermObligationsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/OtherLongTermObligationsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/PrepaidExpensesAndDeposits" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/PrepaidExpensesAndDepositsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/PrepaidExpensesAndDepositsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/PropertyPlantAndEquipment" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/PropertyPlantAndEquipmentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_A6BC448465570DCE8ECA0D7ACCB9FBB7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_A6BC448465570DCE8ECA0D7ACCB9FBB7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_6E3BD34A67AF594BA8190D7ACCB94F8C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_A6BC448465570DCE8ECA0D7ACCB9FBB7" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_6E3BD34A67AF594BA8190D7ACCB94F8C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_6E3BD34A67AF594BA8190D7ACCB94F8C" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_6E3BD34A67AF594BA8190D7ACCB94F8C" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquipmentMember" xlink:label="loc_us-gaap_EquipmentMember_20421708B838527D87CB0D7ACCBA79DC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:to="loc_us-gaap_EquipmentMember_20421708B838527D87CB0D7ACCBA79DC" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_MajorComponentPartsInUseMember" xlink:label="loc_noa_MajorComponentPartsInUseMember_53A91933F037D333E6330D7ACCBA81DE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:to="loc_noa_MajorComponentPartsInUseMember_53A91933F037D333E6330D7ACCBA81DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherMachineryAndEquipmentMember" xlink:label="loc_us-gaap_OtherMachineryAndEquipmentMember_04683A339FF42D27E0EC0D7ACCBABDED" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:to="loc_us-gaap_OtherMachineryAndEquipmentMember_04683A339FF42D27E0EC0D7ACCBABDED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VehiclesMember" xlink:label="loc_us-gaap_VehiclesMember_80EB53CE9C20948ED1F60D7ACCBAA463" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:to="loc_us-gaap_VehiclesMember_80EB53CE9C20948ED1F60D7ACCBAA463" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_OfficeAndComputerEquipmentMember" xlink:label="loc_noa_OfficeAndComputerEquipmentMember_74981C36A64487FEF5CB0D7ACCBB78FC" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:to="loc_noa_OfficeAndComputerEquipmentMember_74981C36A64487FEF5CB0D7ACCBB78FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LandMember" xlink:label="loc_us-gaap_LandMember_07B9657A0995F44E2BD10D7ACCBB24FB" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:to="loc_us-gaap_LandMember_07B9657A0995F44E2BD10D7ACCBB24FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BuildingMember" xlink:label="loc_us-gaap_BuildingMember_46D96FC59A21471D33D40D7ACCBBE987" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:to="loc_us-gaap_BuildingMember_46D96FC59A21471D33D40D7ACCBBE987" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_22FA57547A5CF6357DDE0D7ACCBB0C9B" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_22FA57547A5CF6357DDE0D7ACCBB0C9B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsHeldUnderCapitalLeasesMember" xlink:label="loc_us-gaap_AssetsHeldUnderCapitalLeasesMember_76AFD9688254756946580D7ACCBB5092" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3FD2D1ECD9139ADFD59A0D7ACCB91A79" xlink:to="loc_us-gaap_AssetsHeldUnderCapitalLeasesMember_76AFD9688254756946580D7ACCBB5092" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGrossExcludingCapitalLeasedAssets" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGrossExcludingCapitalLeasedAssets_5192ED7127369D34EA640D7ACCBCB614" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGrossExcludingCapitalLeasedAssets_5192ED7127369D34EA640D7ACCBCB614" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipmentExcludingCapitalLeasedAssets" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipmentExcludingCapitalLeasedAssets_792F15A0082CC4BBCD1F0D7ACCBC4C32" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipmentExcludingCapitalLeasedAssets_792F15A0082CC4BBCD1F0D7ACCBC4C32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssets" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssets_6B7B64F6BF08BD70F7650D7ACCBC3212" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNetExcludingCapitalLeasedAssets_6B7B64F6BF08BD70F7650D7ACCBC3212" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasedAssetsGross" xlink:label="loc_us-gaap_CapitalLeasedAssetsGross_825596C6AD12B4E49FCC0D7ACCBC8831" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_CapitalLeasedAssetsGross_825596C6AD12B4E49FCC0D7ACCBC8831" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation" xlink:label="loc_us-gaap_CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation_C10A6ACC4A5AC47DAB9B0D7ACCBC8D9B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation_C10A6ACC4A5AC47DAB9B0D7ACCBC8D9B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:label="loc_us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet_DB640C6822BE209CD9910D7ACCBD128A" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet_DB640C6822BE209CD9910D7ACCBD128A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_EF0623330E9C01604E790D7ACCBD3B12" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_EF0623330E9C01604E790D7ACCBD3B12" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_87726B8CC8537137F2990D7ACCBD5D32" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_87726B8CC8537137F2990D7ACCBD5D32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_6CA206D7F07F64C0A84B0D7ACCBD4DAD" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_6CA206D7F07F64C0A84B0D7ACCBD4DAD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalLeaseObligationsIncurred" xlink:label="loc_us-gaap_CapitalLeaseObligationsIncurred_FDE9A512E250811E1B030D7ACCBDC2F0" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_CapitalLeaseObligationsIncurred_FDE9A512E250811E1B030D7ACCBDC2F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MinimumLeasePaymentsSaleLeasebackTransactions" xlink:label="loc_us-gaap_MinimumLeasePaymentsSaleLeasebackTransactions_235C050A47CD5DA9305F0D7ACCBE9BB2" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_MinimumLeasePaymentsSaleLeasebackTransactions_235C050A47CD5DA9305F0D7ACCBE9BB2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaap_Depreciation_7EAFBF66372B39E4C79E0D7ACCBE3797" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_A626D4133305652F07C40D7ACCBCFDCE" xlink:to="loc_us-gaap_Depreciation_7EAFBF66372B39E4C79E0D7ACCBE3797" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/PropertyPlantAndEquipmentTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RecentAccountingPronouncementsNotYetAdopted" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RelatedPartyTransactions" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RelatedPartyTransactionsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0D16C37D77BA3C05D3671BD36EE9B555" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0D16C37D77BA3C05D3671BD36EE9B555" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_4D6B6DF2B5469D81ACD51BD36EEA3C2F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_0D16C37D77BA3C05D3671BD36EE9B555" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_4D6B6DF2B5469D81ACD51BD36EEA3C2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6BA07851EA14B461537D1BD36EEFC099_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_4D6B6DF2B5469D81ACD51BD36EEA3C2F" xlink:to="loc_us-gaap_RelatedPartyDomain_6BA07851EA14B461537D1BD36EEFC099_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_6BA07851EA14B461537D1BD36EEFC099" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_4D6B6DF2B5469D81ACD51BD36EEA3C2F" xlink:to="loc_us-gaap_RelatedPartyDomain_6BA07851EA14B461537D1BD36EEFC099" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CorporateJointVentureMember" xlink:label="loc_us-gaap_CorporateJointVentureMember_E4CCC3C39B3B7B849D911BD36EF02157" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6BA07851EA14B461537D1BD36EEFC099" xlink:to="loc_us-gaap_CorporateJointVentureMember_E4CCC3C39B3B7B849D911BD36EF02157" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_AffiliatedEntityMember" xlink:label="loc_srt_AffiliatedEntityMember_16C9A7D2F647724C5EA01BD36EF07E54" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6BA07851EA14B461537D1BD36EEFC099" xlink:to="loc_srt_AffiliatedEntityMember_16C9A7D2F647724C5EA01BD36EF07E54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DirectorMember" xlink:label="loc_us-gaap_DirectorMember_874D7C1982A17D351B661BD36EF0D146" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6BA07851EA14B461537D1BD36EEFC099" xlink:to="loc_us-gaap_DirectorMember_874D7C1982A17D351B661BD36EF0D146" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesIncomeStatementSubleaseRevenue" xlink:label="loc_us-gaap_OperatingLeasesIncomeStatementSubleaseRevenue_1F5C2EC03D203B2026041BD36EF17F0F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:to="loc_us-gaap_OperatingLeasesIncomeStatementSubleaseRevenue_1F5C2EC03D203B2026041BD36EF17F0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:label="loc_us-gaap_RevenueFromRelatedParties_7A8834D65279A8E25FD41BD36EF102BC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:to="loc_us-gaap_RevenueFromRelatedParties_7A8834D65279A8E25FD41BD36EF102BC" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ManagementFeeRevenueFromRelatedParties" xlink:label="loc_noa_ManagementFeeRevenueFromRelatedParties_D524715F0A66E08567991BD36EF13422" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:to="loc_noa_ManagementFeeRevenueFromRelatedParties_D524715F0A66E08567991BD36EF13422" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeRelatedParty" xlink:label="loc_us-gaap_InterestIncomeRelatedParty_E90C8C4C15E606AA23ED1BD36EF20289" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:to="loc_us-gaap_InterestIncomeRelatedParty_E90C8C4C15E606AA23ED1BD36EF20289" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_RelatedPartyTransactionDistributionsToRelatedParty" xlink:label="loc_noa_RelatedPartyTransactionDistributionsToRelatedParty_1D32F6DE5349F4324EC51BD36EF2BB70" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:to="loc_noa_RelatedPartyTransactionDistributionsToRelatedParty_1D32F6DE5349F4324EC51BD36EF2BB70" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_RelatedPartyTransactionOfficeAndGeneralExpensesFromTransactionsWithRelatedParty" xlink:label="loc_noa_RelatedPartyTransactionOfficeAndGeneralExpensesFromTransactionsWithRelatedParty_23D075A93C2E31F92F501BD36EF26728" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:to="loc_noa_RelatedPartyTransactionOfficeAndGeneralExpensesFromTransactionsWithRelatedParty_23D075A93C2E31F92F501BD36EF26728" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_1E9BFEE05603FE5290E51BD36EF2F6FF" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_1E9BFEE05603FE5290E51BD36EF2F6FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsReceivableRelatedPartiesCurrent" xlink:label="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_D2330DD0488AD6FD90051BD36EF2F17A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_188CEEA7C875899485691BD36EF09B0C" xlink:to="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_D2330DD0488AD6FD90051BD36EF2F17A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RelatedPartyTransactionsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/Revenue" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RevenueContractBalancesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RevenueContractCostsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalizedContractCostLineItems" xlink:label="loc_us-gaap_CapitalizedContractCostLineItems_EAD00AA14863930AECF6169677101E88" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalizedContractCostTable" xlink:label="loc_us-gaap_CapitalizedContractCostTable_9A076660D95DFF404FB51696770EF14E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_EAD00AA14863930AECF6169677101E88" xlink:to="loc_us-gaap_CapitalizedContractCostTable_9A076660D95DFF404FB51696770EF14E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalizedContractCostAxis" xlink:label="loc_us-gaap_CapitalizedContractCostAxis_B6CA19320D9D467B967D1696770FD107" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CapitalizedContractCostTable_9A076660D95DFF404FB51696770EF14E" xlink:to="loc_us-gaap_CapitalizedContractCostAxis_B6CA19320D9D467B967D1696770FD107" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalizedContractCostDomain" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_947C2DAB6D6B95D03C541696770F1FF0_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_B6CA19320D9D467B967D1696770FD107" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_947C2DAB6D6B95D03C541696770F1FF0_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalizedContractCostDomain" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_947C2DAB6D6B95D03C541696770F1FF0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_B6CA19320D9D467B967D1696770FD107" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_947C2DAB6D6B95D03C541696770F1FF0" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CapitalizedContractCostReimbursableBidCostsMember" xlink:label="loc_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_947C2DAB6D6B95D03C541696770F1FF0" xlink:to="loc_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CapitalizedContractCostFulfillmentCostMember" xlink:label="loc_noa_CapitalizedContractCostFulfillmentCostMember_7FF666D122AD29A4307416967710299C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_947C2DAB6D6B95D03C541696770F1FF0" xlink:to="loc_noa_CapitalizedContractCostFulfillmentCostMember_7FF666D122AD29A4307416967710299C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalizedContractCostNet" xlink:label="loc_us-gaap_CapitalizedContractCostNet_043244305E53B0B0F36E16967710B933" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_EAD00AA14863930AECF6169677101E88" xlink:to="loc_us-gaap_CapitalizedContractCostNet_043244305E53B0B0F36E16967710B933" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CapitalizedContractCostAdditions" xlink:label="loc_noa_CapitalizedContractCostAdditions_D0521CB3D79259CD474916967711E697" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_EAD00AA14863930AECF6169677101E88" xlink:to="loc_noa_CapitalizedContractCostAdditions_D0521CB3D79259CD474916967711E697" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RevenueDisaggregationOfRevenueDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_BD3F4A5A7B7FB5686757E4A070A44C7F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_FA174F8ED48D5D898B04E4A0708FD763" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_BD3F4A5A7B7FB5686757E4A070A44C7F" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_FA174F8ED48D5D898B04E4A0708FD763" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="noa-20181231.xsd#noa_RevenueRecognitionMethodAxis" xlink:label="loc_noa_RevenueRecognitionMethodAxis_1CDA48707CD81FB2E980E4B564B8DBDC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_FA174F8ED48D5D898B04E4A0708FD763" xlink:to="loc_noa_RevenueRecognitionMethodAxis_1CDA48707CD81FB2E980E4B564B8DBDC" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_RevenueRecognitionMethodDomain" xlink:label="loc_noa_RevenueRecognitionMethodDomain_E8BFE4A8C32E2B35163EE4B564CADFA5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_noa_RevenueRecognitionMethodAxis_1CDA48707CD81FB2E980E4B564B8DBDC" xlink:to="loc_noa_RevenueRecognitionMethodDomain_E8BFE4A8C32E2B35163EE4B564CADFA5_default" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_RevenueRecognitionMethodDomain" xlink:label="loc_noa_RevenueRecognitionMethodDomain_E8BFE4A8C32E2B35163EE4B564CADFA5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_noa_RevenueRecognitionMethodAxis_1CDA48707CD81FB2E980E4B564B8DBDC" xlink:to="loc_noa_RevenueRecognitionMethodDomain_E8BFE4A8C32E2B35163EE4B564CADFA5" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_RevenueRecognitionMethodCostToCostPercentCompleteMember" xlink:label="loc_noa_RevenueRecognitionMethodCostToCostPercentCompleteMember_C4E979BC64C3243E3428E4B5F5A24979" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_RevenueRecognitionMethodDomain_E8BFE4A8C32E2B35163EE4B564CADFA5" xlink:to="loc_noa_RevenueRecognitionMethodCostToCostPercentCompleteMember_C4E979BC64C3243E3428E4B5F5A24979" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_RevenueRecognitionMethodAsInvoicedMember" xlink:label="loc_noa_RevenueRecognitionMethodAsInvoicedMember_122535AD999D8714B2C8E4B66426DEA6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_noa_RevenueRecognitionMethodDomain_E8BFE4A8C32E2B35163EE4B564CADFA5" xlink:to="loc_noa_RevenueRecognitionMethodAsInvoicedMember_122535AD999D8714B2C8E4B66426DEA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_329185558B3C99142325E4A070902E45" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_FA174F8ED48D5D898B04E4A0708FD763" xlink:to="loc_srt_ProductOrServiceAxis_329185558B3C99142325E4A070902E45" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_0B847043AEC74A2EF15CE4A07091370C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_329185558B3C99142325E4A070902E45" xlink:to="loc_srt_ProductsAndServicesDomain_0B847043AEC74A2EF15CE4A07091370C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_0B847043AEC74A2EF15CE4A07091370C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_329185558B3C99142325E4A070902E45" xlink:to="loc_srt_ProductsAndServicesDomain_0B847043AEC74A2EF15CE4A07091370C" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ConstructionServicesMember" xlink:label="loc_noa_ConstructionServicesMember_C05A7473D634CEEC9919E4A982C8DFBB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_0B847043AEC74A2EF15CE4A07091370C" xlink:to="loc_noa_ConstructionServicesMember_C05A7473D634CEEC9919E4A982C8DFBB" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_OperationsSupportServicesMember" xlink:label="loc_noa_OperationsSupportServicesMember_6179EC5D8531E5923BABE4AA0D4DAD1C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_0B847043AEC74A2EF15CE4A07091370C" xlink:to="loc_noa_OperationsSupportServicesMember_6179EC5D8531E5923BABE4AA0D4DAD1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingAxis" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_B6D150BBC943F5DDAFD4E4A07094F52E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_FA174F8ED48D5D898B04E4A0708FD763" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_B6D150BBC943F5DDAFD4E4A07094F52E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_5419A9AFEA691E92FAEEE4A07097ADC3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_B6D150BBC943F5DDAFD4E4A07094F52E" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_5419A9AFEA691E92FAEEE4A07097ADC3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_5419A9AFEA691E92FAEEE4A07097ADC3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_B6D150BBC943F5DDAFD4E4A07094F52E" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_5419A9AFEA691E92FAEEE4A07097ADC3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeAndMaterialsContractMember" xlink:label="loc_us-gaap_TimeAndMaterialsContractMember_4E7D211D8E8DCE4E171CE4ABB92C788A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_5419A9AFEA691E92FAEEE4A07097ADC3" xlink:to="loc_us-gaap_TimeAndMaterialsContractMember_4E7D211D8E8DCE4E171CE4ABB92C788A" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_UnitPriceContractMember" xlink:label="loc_noa_UnitPriceContractMember_0385B8EB555162C94B06E4ACC68A5DD7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_5419A9AFEA691E92FAEEE4A07097ADC3" xlink:to="loc_noa_UnitPriceContractMember_0385B8EB555162C94B06E4ACC68A5DD7" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CostPlusContractMember" xlink:label="loc_noa_CostPlusContractMember_B5F7B9B41CB587072382E4AD1D96A37B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_5419A9AFEA691E92FAEEE4A07097ADC3" xlink:to="loc_noa_CostPlusContractMember_B5F7B9B41CB587072382E4AD1D96A37B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_B854078C9D39E85FC00AE4A351B64CF1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_BD3F4A5A7B7FB5686757E4A070A44C7F" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_B854078C9D39E85FC00AE4A351B64CF1" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RevenueEstimatedRevenueExpectedToBeRecognizedInFutureRelatedToPerformanceObligationsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_C4ED2285E4681B3DDA3916967720FF3C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_5AB5586A944C272682421696771F1245" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_C4ED2285E4681B3DDA3916967720FF3C" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_5AB5586A944C272682421696771F1245" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_123D80BBB7943EDBC3D31696771F5132" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_5AB5586A944C272682421696771F1245" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_123D80BBB7943EDBC3D31696771F5132" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_77F5FEA0C84FD965C3341696772020F9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_C4ED2285E4681B3DDA3916967720FF3C" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_77F5FEA0C84FD965C3341696772020F9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RevenueScheduleOfMajorCustomersDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_56E8D9E0F880F450391AE4C7F2380183" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="loc_us-gaap_ConcentrationRiskTable_50E367AAE7ED4A7EC9C9E4C7F2370825" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_56E8D9E0F880F450391AE4C7F2380183" xlink:to="loc_us-gaap_ConcentrationRiskTable_50E367AAE7ED4A7EC9C9E4C7F2370825" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MajorCustomersAxis" xlink:label="loc_srt_MajorCustomersAxis_729DC87328C378EED6F6E4CA5135DEA6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_50E367AAE7ED4A7EC9C9E4C7F2370825" xlink:to="loc_srt_MajorCustomersAxis_729DC87328C378EED6F6E4CA5135DEA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_DF8496D36AA9290D8798E4CA51375033_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_729DC87328C378EED6F6E4CA5135DEA6" xlink:to="loc_srt_NameOfMajorCustomerDomain_DF8496D36AA9290D8798E4CA51375033_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_DF8496D36AA9290D8798E4CA51375033" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_729DC87328C378EED6F6E4CA5135DEA6" xlink:to="loc_srt_NameOfMajorCustomerDomain_DF8496D36AA9290D8798E4CA51375033" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CustomerMember" xlink:label="loc_noa_CustomerMember_EE87104C67C5ADBAAD35E4CA7D6195DB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_DF8496D36AA9290D8798E4CA51375033" xlink:to="loc_noa_CustomerMember_EE87104C67C5ADBAAD35E4CA7D6195DB" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CustomerBMember" xlink:label="loc_noa_CustomerBMember_4B1054E156C4BA08C664E4CADC0B5FF3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_DF8496D36AA9290D8798E4CA51375033" xlink:to="loc_noa_CustomerBMember_4B1054E156C4BA08C664E4CADC0B5FF3" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CustomerCMember" xlink:label="loc_noa_CustomerCMember_5EA5A2F672DC3562A892E4CE443D9AF1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_DF8496D36AA9290D8798E4CA51375033" xlink:to="loc_noa_CustomerCMember_5EA5A2F672DC3562A892E4CE443D9AF1" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_CustomerDMember" xlink:label="loc_noa_CustomerDMember_F6EB226319FFDB9BD21CE4D04E22A2F1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_DF8496D36AA9290D8798E4CA51375033" xlink:to="loc_noa_CustomerDMember_F6EB226319FFDB9BD21CE4D04E22A2F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_3EA61FC4F8B355CA60F7E4C99CF963CC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_50E367AAE7ED4A7EC9C9E4C7F2370825" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_3EA61FC4F8B355CA60F7E4C99CF963CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_35CDAB07703CB923C422E4C99CFBF0E1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_3EA61FC4F8B355CA60F7E4C99CF963CC" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_35CDAB07703CB923C422E4C99CFBF0E1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_35CDAB07703CB923C422E4C99CFBF0E1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_3EA61FC4F8B355CA60F7E4C99CF963CC" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_35CDAB07703CB923C422E4C99CFBF0E1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_063AEB639218FD6A2A1CE4C9DFAD39B1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_35CDAB07703CB923C422E4C99CFBF0E1" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_063AEB639218FD6A2A1CE4C9DFAD39B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_BFFE251006DE25A64318E4C932DAFBDE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_50E367AAE7ED4A7EC9C9E4C7F2370825" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_BFFE251006DE25A64318E4C932DAFBDE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_493E0AAB1AC03E66A28AE4C932E0D9C8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_BFFE251006DE25A64318E4C932DAFBDE" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_493E0AAB1AC03E66A28AE4C932E0D9C8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_493E0AAB1AC03E66A28AE4C932E0D9C8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_BFFE251006DE25A64318E4C932DAFBDE" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_493E0AAB1AC03E66A28AE4C932E0D9C8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueFromContractWithCustomerMember" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_5FC2A32BF3B287216437E4C97823EFED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_493E0AAB1AC03E66A28AE4C932E0D9C8" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_5FC2A32BF3B287216437E4C97823EFED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_D671E9E24C429EF94292E4C8E8695BBF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_56E8D9E0F880F450391AE4C7F2380183" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_D671E9E24C429EF94292E4C8E8695BBF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RevenueTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/RevenueUnpricedContractModificationsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_E4ACD7AB9F069CE1C0A2E79DEF239553" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_A2826BE4BE1903637FABE79DEF096872" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_E4ACD7AB9F069CE1C0A2E79DEF239553" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_A2826BE4BE1903637FABE79DEF096872" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_5A25B7D824957A6B1F9AE7A664CAFF0E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_A2826BE4BE1903637FABE79DEF096872" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_5A25B7D824957A6B1F9AE7A664CAFF0E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_DC41A324E01F2DEA9B1BE7A664D72F05_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_5A25B7D824957A6B1F9AE7A664CAFF0E" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_DC41A324E01F2DEA9B1BE7A664D72F05_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_DC41A324E01F2DEA9B1BE7A664D72F05" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_5A25B7D824957A6B1F9AE7A664CAFF0E" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_DC41A324E01F2DEA9B1BE7A664D72F05" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AccountsAndOtherReceivablesNetCurrentMember" xlink:label="loc_noa_AccountsAndOtherReceivablesNetCurrentMember_0C0B6FBE6605B7723E0BE7A75ECEC014" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_DC41A324E01F2DEA9B1BE7A664D72F05" xlink:to="loc_noa_AccountsAndOtherReceivablesNetCurrentMember_0C0B6FBE6605B7723E0BE7A75ECEC014" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ContractWithCustomerAssetNetCurrentMember" xlink:label="loc_noa_ContractWithCustomerAssetNetCurrentMember_29BCA2D3FD9C3CAAC73BE7A7EBAF0B5C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_DC41A324E01F2DEA9B1BE7A664D72F05" xlink:to="loc_noa_ContractWithCustomerAssetNetCurrentMember_29BCA2D3FD9C3CAAC73BE7A7EBAF0B5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_75D7E852F31110E62446E79DEF0A5AE9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_A2826BE4BE1903637FABE79DEF096872" xlink:to="loc_srt_ProductOrServiceAxis_75D7E852F31110E62446E79DEF0A5AE9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_15D764FAD3F771667EA9E79DEF0BE330_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_75D7E852F31110E62446E79DEF0A5AE9" xlink:to="loc_srt_ProductsAndServicesDomain_15D764FAD3F771667EA9E79DEF0BE330_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_15D764FAD3F771667EA9E79DEF0BE330" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_75D7E852F31110E62446E79DEF0A5AE9" xlink:to="loc_srt_ProductsAndServicesDomain_15D764FAD3F771667EA9E79DEF0BE330" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_VariableConsiderationUnpricedContractModificationsMember" xlink:label="loc_noa_VariableConsiderationUnpricedContractModificationsMember_839D17F006B34F1D2050E79F7C8B7634" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_15D764FAD3F771667EA9E79DEF0BE330" xlink:to="loc_noa_VariableConsiderationUnpricedContractModificationsMember_839D17F006B34F1D2050E79F7C8B7634" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_5E8F6A7D6935023034B9E79E6295922F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_E4ACD7AB9F069CE1C0A2E79DEF239553" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_5E8F6A7D6935023034B9E79E6295922F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerAssetAccumulatedAllowanceForCreditLoss" xlink:label="loc_us-gaap_ContractWithCustomerAssetAccumulatedAllowanceForCreditLoss_72FC71F5FD69C96BF1FCE7A6003678FE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_E4ACD7AB9F069CE1C0A2E79DEF239553" xlink:to="loc_us-gaap_ContractWithCustomerAssetAccumulatedAllowanceForCreditLoss_72FC71F5FD69C96BF1FCE7A6003678FE" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/Shares" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SharesCommonSharesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_07F128B533E6921C56060D1D077E4618" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1FA8550F6A0DDCB4C75C0D1D077C952A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_07F128B533E6921C56060D1D077E4618" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1FA8550F6A0DDCB4C75C0D1D077C952A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_4BB0F723D9D135C308E50D1D077C038A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1FA8550F6A0DDCB4C75C0D1D077C952A" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_4BB0F723D9D135C308E50D1D077C038A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_218C38CC9B99B4528FEF0D1D077D695A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4BB0F723D9D135C308E50D1D077C038A" xlink:to="loc_us-gaap_EquityComponentDomain_218C38CC9B99B4528FEF0D1D077D695A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_218C38CC9B99B4528FEF0D1D077D695A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4BB0F723D9D135C308E50D1D077C038A" xlink:to="loc_us-gaap_EquityComponentDomain_218C38CC9B99B4528FEF0D1D077D695A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_E59285423917F988E68F0D1D077ED943" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_218C38CC9B99B4528FEF0D1D077D695A" xlink:to="loc_us-gaap_CommonStockMember_E59285423917F988E68F0D1D077ED943" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="loc_us-gaap_TreasuryStockMember_F90DF8E5ED68571550DF0D1D077EAD95" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_218C38CC9B99B4528FEF0D1D077D695A" xlink:to="loc_us-gaap_TreasuryStockMember_F90DF8E5ED68571550DF0D1D077EAD95" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3EE80DCB076B5BC283370D1D077EDE8E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_07F128B533E6921C56060D1D077E4618" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3EE80DCB076B5BC283370D1D077EDE8E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="loc_us-gaap_SharesOutstanding_045FAF015BCB25BAFA200D1D077F7032" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3EE80DCB076B5BC283370D1D077EDE8E" xlink:to="loc_us-gaap_SharesOutstanding_045FAF015BCB25BAFA200D1D077F7032" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_1D556D69E979ADBB1A2E0D1D077F2BDC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3EE80DCB076B5BC283370D1D077EDE8E" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_1D556D69E979ADBB1A2E0D1D077F2BDC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_9F251332E40C1D769DA30D1D077FEA4D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3EE80DCB076B5BC283370D1D077EDE8E" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_9F251332E40C1D769DA30D1D077FEA4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TreasuryStockSharesAcquired" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_D36BEBC97973478931AD0D1D077F5289" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3EE80DCB076B5BC283370D1D077EDE8E" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_D36BEBC97973478931AD0D1D077F5289" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_StockIssuedDuringPeriodSharesTreasuryStockReissuedtoSatisfySharedbasedCompensationObligations" xlink:label="loc_noa_StockIssuedDuringPeriodSharesTreasuryStockReissuedtoSatisfySharedbasedCompensationObligations_23FBAC7B21A345C1353A0D1D07801FF3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3EE80DCB076B5BC283370D1D077EDE8E" xlink:to="loc_noa_StockIssuedDuringPeriodSharesTreasuryStockReissuedtoSatisfySharedbasedCompensationObligations_23FBAC7B21A345C1353A0D1D07801FF3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_217C2313A80196E24A4C0D1D078031DF" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3EE80DCB076B5BC283370D1D077EDE8E" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_217C2313A80196E24A4C0D1D078031DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_060A003C10F19199A0120D1D078053E8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_07F128B533E6921C56060D1D077E4618" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_060A003C10F19199A0120D1D078053E8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_9D5A517D9D087D371CAA0D1D0780E574" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_07F128B533E6921C56060D1D077E4618" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_9D5A517D9D087D371CAA0D1D0780E574" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SharesDividendsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SharesNetIncomePerShareDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_5D16A85272E7D1D9529222E3EA7F09EA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_4E24B7F1CE26D2704AFD22E3EA7EF30C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_5D16A85272E7D1D9529222E3EA7F09EA" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_4E24B7F1CE26D2704AFD22E3EA7EF30C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_754C31FEA204CA30AA8222E3EA7E5A85" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_4E24B7F1CE26D2704AFD22E3EA7EF30C" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_754C31FEA204CA30AA8222E3EA7E5A85" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_EE216E5AE5818F35D04222E3EA7EE707_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_754C31FEA204CA30AA8222E3EA7E5A85" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_EE216E5AE5818F35D04222E3EA7EE707_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_EE216E5AE5818F35D04222E3EA7EE707" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_754C31FEA204CA30AA8222E3EA7E5A85" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_EE216E5AE5818F35D04222E3EA7EE707" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_175E58344B311C74C6D822E3EA7F8245" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_EE216E5AE5818F35D04222E3EA7EE707" xlink:to="loc_us-gaap_EmployeeStockOptionMember_175E58344B311C74C6D822E3EA7F8245" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="loc_us-gaap_TreasuryStockMember_088598E1790E19B29EB922E3EA7F1C7D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_EE216E5AE5818F35D04222E3EA7EE707" xlink:to="loc_us-gaap_TreasuryStockMember_088598E1790E19B29EB922E3EA7F1C7D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConvertibleDebtSecuritiesMember" xlink:label="loc_us-gaap_ConvertibleDebtSecuritiesMember_F559459CDAC8D6BC09B422E3EA7FE6CB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_EE216E5AE5818F35D04222E3EA7EE707" xlink:to="loc_us-gaap_ConvertibleDebtSecuritiesMember_F559459CDAC8D6BC09B422E3EA7FE6CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_69BAE8BBDE046EC8298F22E3EA805350" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_5D16A85272E7D1D9529222E3EA7F09EA" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_69BAE8BBDE046EC8298F22E3EA805350" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SharesSharePurchaseProgramDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityClassOfTreasuryStockLineItems" xlink:label="loc_us-gaap_EquityClassOfTreasuryStockLineItems_441DAC65FBD74BC431372037139E31DA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassOfTreasuryStockTable" xlink:label="loc_us-gaap_ClassOfTreasuryStockTable_86127DF557F9C10CA83E2037139B332C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_441DAC65FBD74BC431372037139E31DA" xlink:to="loc_us-gaap_ClassOfTreasuryStockTable_86127DF557F9C10CA83E2037139B332C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_D7C703C6C05E748CA6A22037139C8E31" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfTreasuryStockTable_86127DF557F9C10CA83E2037139B332C" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_D7C703C6C05E748CA6A22037139C8E31" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_D98C7DD4F343486B63722037139CD4CF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_D7C703C6C05E748CA6A22037139C8E31" xlink:to="loc_us-gaap_EquityComponentDomain_D98C7DD4F343486B63722037139CD4CF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_D98C7DD4F343486B63722037139CD4CF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_D7C703C6C05E748CA6A22037139C8E31" xlink:to="loc_us-gaap_EquityComponentDomain_D98C7DD4F343486B63722037139CD4CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_4FD0FDBD0950D7429FC52037139C7BAC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_D98C7DD4F343486B63722037139CD4CF" xlink:to="loc_us-gaap_CommonStockMember_4FD0FDBD0950D7429FC52037139C7BAC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_6BA7E50F2A56004C426A2037139D5FDD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_D98C7DD4F343486B63722037139CD4CF" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_6BA7E50F2A56004C426A2037139D5FDD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:label="loc_us-gaap_ShareRepurchaseProgramAxis_986BD22BA714C51CE5182037139DE5F8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfTreasuryStockTable_86127DF557F9C10CA83E2037139B332C" xlink:to="loc_us-gaap_ShareRepurchaseProgramAxis_986BD22BA714C51CE5182037139DE5F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_635DD946BEB688CCE2692037139DD005_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_986BD22BA714C51CE5182037139DE5F8" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_635DD946BEB688CCE2692037139DD005_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_635DD946BEB688CCE2692037139DD005" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_986BD22BA714C51CE5182037139DE5F8" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_635DD946BEB688CCE2692037139DD005" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_A2017ShareRepurchaseProgramMember" xlink:label="loc_noa_A2017ShareRepurchaseProgramMember_67D97E651D728EB099692037139D31CA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_635DD946BEB688CCE2692037139DD005" xlink:to="loc_noa_A2017ShareRepurchaseProgramMember_67D97E651D728EB099692037139D31CA" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_A2016ShareRepurchaseProgramMember" xlink:label="loc_noa_A2016ShareRepurchaseProgramMember_66FE1914F0BB143321C42037139EC3A7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_635DD946BEB688CCE2692037139DD005" xlink:to="loc_noa_A2016ShareRepurchaseProgramMember_66FE1914F0BB143321C42037139EC3A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:label="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_669FE723F808F60F11B32037139EF9B7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_441DAC65FBD74BC431372037139E31DA" xlink:to="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_669FE723F808F60F11B32037139EF9B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_96D85AD0BD8B427569C92037139F53D4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_441DAC65FBD74BC431372037139E31DA" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_96D85AD0BD8B427569C92037139F53D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_F65AA82362B9D5377BB72037139F5C40" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_441DAC65FBD74BC431372037139E31DA" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_F65AA82362B9D5377BB72037139F5C40" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SharesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SignificantAccountingPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SignificantAccountingPoliciesIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_D056A27B6146E610FD7F17307DD18586" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_EA16706CE8099756AB9C17307DCE040B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_D056A27B6146E610FD7F17307DD18586" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_EA16706CE8099756AB9C17307DCE040B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_718F3052CE361ECA016E17307DCF8A18" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_EA16706CE8099756AB9C17307DCE040B" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_718F3052CE361ECA016E17307DCF8A18" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_718F3052CE361ECA016E17307DCF8A18" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_718F3052CE361ECA016E17307DCF8A18" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:label="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_C0C01C3E82724BBF176417307DCF01B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F" xlink:to="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_C0C01C3E82724BBF176417307DCF01B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CustomerContractsMember" xlink:label="loc_us-gaap_CustomerContractsMember_A920E64BAB2ACCDFB1A317307DD00F15" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F" xlink:to="loc_us-gaap_CustomerContractsMember_A920E64BAB2ACCDFB1A317307DD00F15" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OffMarketFavorableLeaseMember" xlink:label="loc_us-gaap_OffMarketFavorableLeaseMember_9643E534A420B5A9257117307DD0CBEF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F" xlink:to="loc_us-gaap_OffMarketFavorableLeaseMember_9643E534A420B5A9257117307DD0CBEF" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_AssembledWorkforceMember" xlink:label="loc_noa_AssembledWorkforceMember_D8B70ACE91D007B20D9D17307DD0F47B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F" xlink:to="loc_noa_AssembledWorkforceMember_D8B70ACE91D007B20D9D17307DD0F47B" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_PartnershipRelationshipsMember" xlink:label="loc_noa_PartnershipRelationshipsMember_A54E21676ECC2D4C477A17307DD0C47D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F" xlink:to="loc_noa_PartnershipRelationshipsMember_A54E21676ECC2D4C477A17307DD0C47D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TrademarksAndTradeNamesMember" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_50E3F24D3202BB596D4917438AC750C4" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_A4C828043D30C5A94A0717307DCFB76F" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_50E3F24D3202BB596D4917438AC750C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_7D7ED411FC6FAE06110217307DD17ACF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_EA16706CE8099756AB9C17307DCE040B" xlink:to="loc_srt_RangeAxis_7D7ED411FC6FAE06110217307DD17ACF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_7213CC003064F15C653A17307DD1CF05_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_7D7ED411FC6FAE06110217307DD17ACF" xlink:to="loc_srt_RangeMember_7213CC003064F15C653A17307DD1CF05_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_7213CC003064F15C653A17307DD1CF05" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_7D7ED411FC6FAE06110217307DD17ACF" xlink:to="loc_srt_RangeMember_7213CC003064F15C653A17307DD1CF05" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_5F11EB1927F42D174CB417307DD1E7B2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_7213CC003064F15C653A17307DD1CF05" xlink:to="loc_srt_MinimumMember_5F11EB1927F42D174CB417307DD1E7B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_71116CEA169D838224DF17307DD1BFDB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_7213CC003064F15C653A17307DD1CF05" xlink:to="loc_srt_MaximumMember_71116CEA169D838224DF17307DD1BFDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_410CDB7F8CDFC2D9186B17307DD24DD2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_D056A27B6146E610FD7F17307DD18586" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_410CDB7F8CDFC2D9186B17307DD24DD2" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SignificantAccountingPoliciesPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SignificantAccountingPoliciesPropertyPlantAndEquipmentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_E6D429828F212C4E249CAA17D6D75918" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_CC9F9D445A0E54A97682AA17D6D4EBD1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_E6D429828F212C4E249CAA17D6D75918" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_CC9F9D445A0E54A97682AA17D6D4EBD1" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_C688D7ABFAD5D609017BAA17D6D4DA45" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_CC9F9D445A0E54A97682AA17D6D4EBD1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_C688D7ABFAD5D609017BAA17D6D4DA45" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_C688D7ABFAD5D609017BAA17D6D4DA45" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_C688D7ABFAD5D609017BAA17D6D4DA45" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_HeavyEquipmentMember" xlink:label="loc_noa_HeavyEquipmentMember_98121BC9250E9D79703BAA17D6D57246" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711" xlink:to="loc_noa_HeavyEquipmentMember_98121BC9250E9D79703BAA17D6D57246" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_MajorComponentPartsInUseMember" xlink:label="loc_noa_MajorComponentPartsInUseMember_2D0DDFCF052651DA20F1AA17D6D5786A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711" xlink:to="loc_noa_MajorComponentPartsInUseMember_2D0DDFCF052651DA20F1AA17D6D5786A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherMachineryAndEquipmentMember" xlink:label="loc_us-gaap_OtherMachineryAndEquipmentMember_46117D61719CF2FFA275AA17D6D5CDF6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711" xlink:to="loc_us-gaap_OtherMachineryAndEquipmentMember_46117D61719CF2FFA275AA17D6D5CDF6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VehiclesMember" xlink:label="loc_us-gaap_VehiclesMember_A9643B55EC44A42DE2B4AA17D6D5EC04" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711" xlink:to="loc_us-gaap_VehiclesMember_A9643B55EC44A42DE2B4AA17D6D5EC04" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_OfficeAndComputerEquipmentMember" xlink:label="loc_noa_OfficeAndComputerEquipmentMember_C748EBFAF37538890A72AA17D6D6009F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711" xlink:to="loc_noa_OfficeAndComputerEquipmentMember_C748EBFAF37538890A72AA17D6D6009F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_7C735AF394B32540478FAAADBE92AD24" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_7C735AF394B32540478FAAADBE92AD24" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BuildingMember" xlink:label="loc_us-gaap_BuildingMember_A4682C42FEF9AB7AA341AA17D6D6A2D7" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_A932A7512A61E5402275AA17D6D5D711" xlink:to="loc_us-gaap_BuildingMember_A4682C42FEF9AB7AA341AA17D6D6A2D7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_40F334236B55B4CB7318AA17D6D69DD1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_CC9F9D445A0E54A97682AA17D6D4EBD1" xlink:to="loc_srt_RangeAxis_40F334236B55B4CB7318AA17D6D69DD1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_C232142E11BFFD8B1EDFAA17D6D6E249_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_40F334236B55B4CB7318AA17D6D69DD1" xlink:to="loc_srt_RangeMember_C232142E11BFFD8B1EDFAA17D6D6E249_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_C232142E11BFFD8B1EDFAA17D6D6E249" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_40F334236B55B4CB7318AA17D6D69DD1" xlink:to="loc_srt_RangeMember_C232142E11BFFD8B1EDFAA17D6D6E249" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_AD013C5B88A26B34F5A7AA17D6D6513B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_C232142E11BFFD8B1EDFAA17D6D6E249" xlink:to="loc_srt_MinimumMember_AD013C5B88A26B34F5A7AA17D6D6513B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_60C200B1F54C5753674EAA17D6D7BC71" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_C232142E11BFFD8B1EDFAA17D6D6E249" xlink:to="loc_srt_MaximumMember_60C200B1F54C5753674EAA17D6D7BC71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_5CFC99AE4AEE2858892FAA17D6D7BF61" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_E6D429828F212C4E249CAA17D6D75918" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_5CFC99AE4AEE2858892FAA17D6D7BF61" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SignificantAccountingPoliciesStockBasedCompensationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D17405C3C708AA75E220AA17D6C7AEBB" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_A3BFEB82E64CB083C9FCAA17D6C41DFA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D17405C3C708AA75E220AA17D6C7AEBB" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_A3BFEB82E64CB083C9FCAA17D6C41DFA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_863C8955CB23CB4023EEAA17D6C6D5C3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_A3BFEB82E64CB083C9FCAA17D6C41DFA" xlink:to="loc_us-gaap_AwardTypeAxis_863C8955CB23CB4023EEAA17D6C6D5C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_678AA4F55C613C6EE076AA17D6C67917_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_863C8955CB23CB4023EEAA17D6C6D5C3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_678AA4F55C613C6EE076AA17D6C67917_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_678AA4F55C613C6EE076AA17D6C67917" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_863C8955CB23CB4023EEAA17D6C6D5C3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_678AA4F55C613C6EE076AA17D6C67917" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_27343B73635717A04D37AA17D6C7CF7B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_678AA4F55C613C6EE076AA17D6C67917" xlink:to="loc_us-gaap_RestrictedStockMember_27343B73635717A04D37AA17D6C7CF7B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PhantomShareUnitsPSUsMember" xlink:label="loc_us-gaap_PhantomShareUnitsPSUsMember_441CF9DAD23918D64FB3AA17D6C72673" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_678AA4F55C613C6EE076AA17D6C67917" xlink:to="loc_us-gaap_PhantomShareUnitsPSUsMember_441CF9DAD23918D64FB3AA17D6C72673" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_E72000EE86DC2A433278AA17D6C7D84E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D17405C3C708AA75E220AA17D6C7AEBB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_E72000EE86DC2A433278AA17D6C7D84E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_FD41F2EBEE3F41481736AA17D6C88DCD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D17405C3C708AA75E220AA17D6C7AEBB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_FD41F2EBEE3F41481736AA17D6C88DCD" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfTradingDaysUsedToCalculateWeightedAverageTradingPriceOfCommonStock" xlink:label="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfTradingDaysUsedToCalculateWeightedAverageTradingPriceOfCommonStock_508684E78E667838723AAA17D6C8AEDC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D17405C3C708AA75E220AA17D6C7AEBB" xlink:to="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfTradingDaysUsedToCalculateWeightedAverageTradingPriceOfCommonStock_508684E78E667838723AAA17D6C8AEDC" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardPeriodForRecognition" xlink:label="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardPeriodForRecognition_DDF05833072B63509339AA17D6C8AC2B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D17405C3C708AA75E220AA17D6C7AEBB" xlink:to="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardPeriodForRecognition_DDF05833072B63509339AA17D6C8AC2B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/SignificantAccountingPoliciesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/StockBasedCompensation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.nacg.ca/role/StockBasedCompensationOptionsByExercisePriceRangeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_C0C7DADE32736FD9E298E4694107EC26" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_C0C7DADE32736FD9E298E4694107EC26" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_183982F57203039D3A9FE46941093354" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_C0C7DADE32736FD9E298E4694107EC26" xlink:to="loc_us-gaap_PlanNameAxis_183982F57203039D3A9FE46941093354" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_199E32FA4230D670EB11E469410977DC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_183982F57203039D3A9FE46941093354" xlink:to="loc_us-gaap_PlanNameDomain_199E32FA4230D670EB11E469410977DC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_199E32FA4230D670EB11E469410977DC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_183982F57203039D3A9FE46941093354" xlink:to="loc_us-gaap_PlanNameDomain_199E32FA4230D670EB11E469410977DC" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareOptionPlanMember" xlink:label="loc_noa_ShareOptionPlanMember_B53B1390EDAF1F66573EE46941098722" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_199E32FA4230D670EB11E469410977DC" xlink:to="loc_noa_ShareOptionPlanMember_B53B1390EDAF1F66573EE46941098722" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_26369A49651D9D9822ADE46941094FC6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_C0C7DADE32736FD9E298E4694107EC26" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_26369A49651D9D9822ADE46941094FC6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_26369A49651D9D9822ADE46941094FC6" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_26369A49651D9D9822ADE46941094FC6" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoPointSeventyFiveMember" xlink:label="loc_noa_TwoPointSeventyFiveMember_70507C37F408FF3649AAE469410AD7EC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:to="loc_noa_TwoPointSeventyFiveMember_70507C37F408FF3649AAE469410AD7EC" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TwoPointSeventyNineMember" xlink:label="loc_noa_TwoPointSeventyNineMember_8A8C3BE2F82D9FC6931DE469410A193A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:to="loc_noa_TwoPointSeventyNineMember_8A8C3BE2F82D9FC6931DE469410A193A" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_FivePointNinetyOneMember" xlink:label="loc_noa_FivePointNinetyOneMember_96D01C049371768B9D1DE469410A4987" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:to="loc_noa_FivePointNinetyOneMember_96D01C049371768B9D1DE469410A4987" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_SixPointFiveSixMember" xlink:label="loc_noa_SixPointFiveSixMember_E58C60549DBCF7BEF03FE469410A8DB5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:to="loc_noa_SixPointFiveSixMember_E58C60549DBCF7BEF03FE469410A8DB5" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_EightPointTwentyEightMember" xlink:label="loc_noa_EightPointTwentyEightMember_72BE7FC07967A2BF6790E469410BEF0F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:to="loc_noa_EightPointTwentyEightMember_72BE7FC07967A2BF6790E469410BEF0F" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_EightPointFiftyEightMember" xlink:label="loc_noa_EightPointFiftyEightMember_3CA737A127D83D7FC23BE469410B95B0" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:to="loc_noa_EightPointFiftyEightMember_3CA737A127D83D7FC23BE469410B95B0" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_NinePointThrirtyThreeMember" xlink:label="loc_noa_NinePointThrirtyThreeMember_DE090EB11360B2F9EEDAE469410BA2D1" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:to="loc_noa_NinePointThrirtyThreeMember_DE090EB11360B2F9EEDAE469410BA2D1" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_TenPointOneThreeMember" xlink:label="loc_noa_TenPointOneThreeMember_740AEC31460EFC27D52BE492DDBE7660" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_C9DDB915C33A556ED544E46941098718" xlink:to="loc_noa_TenPointOneThreeMember_740AEC31460EFC27D52BE492DDBE7660" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePrice" xlink:label="loc_noa_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePrice_B1A8C2C159F07A7C61A3E469410CE7D5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_noa_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePrice_B1A8C2C159F07A7C61A3E469410CE7D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_E3962815D6E494FB62F3E469410DA3DD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_E3962815D6E494FB62F3E469410DA3DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_B91C963FBCF8BFF24FCEE469410D13CD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_B91C963FBCF8BFF24FCEE469410D13CD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_BDDB9F798F61E684562BE469410EA7D4" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_BDDB9F798F61E684562BE469410EA7D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_5BCAD46C17BDEC2B0532E469410E8410" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_5BCAD46C17BDEC2B0532E469410E8410" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber_D37B6F431BA7B0430AB1E469410E7BE5" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber_D37B6F431BA7B0430AB1E469410E7BE5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2_17DD9F086BA22ADAA4C8E469410E8C2F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2_17DD9F086BA22ADAA4C8E469410E8C2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_2B41E539F766DD360316E469410F0E25" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_2B41E539F766DD360316E469410F0E25" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_9C04F56A8895F5C8E43DE469410FA607" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_9C04F56A8895F5C8E43DE469410FA607" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_BD7D566232B2F7CB7BFCE469410F675C" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_FA558C83DC4E8593DF00E469410C77EA" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_BD7D566232B2F7CB7BFCE469410F675C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/StockBasedCompensationPerformanceAndDeferredStockUnitPlanDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_826841DAF91188EF1816E8CEF455B152" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_826841DAF91188EF1816E8CEF455B152" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_3F796F22289921E67519E8CEF455B2EC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_826841DAF91188EF1816E8CEF455B152" xlink:to="loc_us-gaap_PlanNameAxis_3F796F22289921E67519E8CEF455B2EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_26F5A45C01D44A3A9E8AE8CEF455FD27_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_3F796F22289921E67519E8CEF455B2EC" xlink:to="loc_us-gaap_PlanNameDomain_26F5A45C01D44A3A9E8AE8CEF455FD27_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_26F5A45C01D44A3A9E8AE8CEF455FD27" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_3F796F22289921E67519E8CEF455B2EC" xlink:to="loc_us-gaap_PlanNameDomain_26F5A45C01D44A3A9E8AE8CEF455FD27" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_PerformanceRestrictedShareUnitPlanMember" xlink:label="loc_noa_PerformanceRestrictedShareUnitPlanMember_8B456265AAD537B0C2D5E8CEF4568392" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_26F5A45C01D44A3A9E8AE8CEF455FD27" xlink:to="loc_noa_PerformanceRestrictedShareUnitPlanMember_8B456265AAD537B0C2D5E8CEF4568392" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_July2014GrantMember" xlink:label="loc_noa_July2014GrantMember_AB77A6F9DD0AFA18506DE8CEF456B8E4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_26F5A45C01D44A3A9E8AE8CEF455FD27" xlink:to="loc_noa_July2014GrantMember_AB77A6F9DD0AFA18506DE8CEF456B8E4" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DeferredShareUnitPlanMember" xlink:label="loc_noa_DeferredShareUnitPlanMember_006D2FE8DB65368225B4E8CEF456C770" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_26F5A45C01D44A3A9E8AE8CEF455FD27" xlink:to="loc_noa_DeferredShareUnitPlanMember_006D2FE8DB65368225B4E8CEF456C770" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_LiabilityClassifiedDeferredStockUnitPlanMember" xlink:label="loc_noa_LiabilityClassifiedDeferredStockUnitPlanMember_BA0894BABC22DBC7285DE8CEF45738F6" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_26F5A45C01D44A3A9E8AE8CEF455FD27" xlink:to="loc_noa_LiabilityClassifiedDeferredStockUnitPlanMember_BA0894BABC22DBC7285DE8CEF45738F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_2643CB1E12A296314F9EE8CEF4571EB8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_826841DAF91188EF1816E8CEF455B152" xlink:to="loc_us-gaap_AwardTypeAxis_2643CB1E12A296314F9EE8CEF4571EB8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADE0AB8C97AB60B166A8E8CEF45723C4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2643CB1E12A296314F9EE8CEF4571EB8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADE0AB8C97AB60B166A8E8CEF45723C4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADE0AB8C97AB60B166A8E8CEF45723C4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2643CB1E12A296314F9EE8CEF4571EB8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADE0AB8C97AB60B166A8E8CEF45723C4" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_PerformanceRestrictedShareUnitsMember" xlink:label="loc_noa_PerformanceRestrictedShareUnitsMember_DDF0D31ABD040873A071E8CEF458359B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADE0AB8C97AB60B166A8E8CEF45723C4" xlink:to="loc_noa_PerformanceRestrictedShareUnitsMember_DDF0D31ABD040873A071E8CEF458359B" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_DeferredStockUnitsDSUsMember" xlink:label="loc_noa_DeferredStockUnitsDSUsMember_4A31054B08DA2D3B62E4E8CEF458F28F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADE0AB8C97AB60B166A8E8CEF45723C4" xlink:to="loc_noa_DeferredStockUnitsDSUsMember_4A31054B08DA2D3B62E4E8CEF458F28F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_CF81A75DA62FFF25CB25E8CEF4583797" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_826841DAF91188EF1816E8CEF455B152" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_CF81A75DA62FFF25CB25E8CEF4583797" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_9CCA3C079C2BE1E91443E8CEF458FD81_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_CF81A75DA62FFF25CB25E8CEF4583797" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_9CCA3C079C2BE1E91443E8CEF458FD81_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_9CCA3C079C2BE1E91443E8CEF458FD81" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_CF81A75DA62FFF25CB25E8CEF4583797" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_9CCA3C079C2BE1E91443E8CEF458FD81" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccruedLiabilitiesMember" xlink:label="loc_us-gaap_AccruedLiabilitiesMember_9CA2F61E2AF3740E7BD6E8CEF4597DA8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_9CCA3C079C2BE1E91443E8CEF458FD81" xlink:to="loc_us-gaap_AccruedLiabilitiesMember_9CA2F61E2AF3740E7BD6E8CEF4597DA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherLiabilitiesMember" xlink:label="loc_us-gaap_OtherLiabilitiesMember_1B69B250FE5760350A90E8CEF45962EF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_9CCA3C079C2BE1E91443E8CEF458FD81" xlink:to="loc_us-gaap_OtherLiabilitiesMember_1B69B250FE5760350A90E8CEF45962EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_439237F2297DEBE4518DE8CEF45A31AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_439237F2297DEBE4518DE8CEF45A31AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_83D6B7B6187A3AFE22A7E8CEF45A3DBD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_83D6B7B6187A3AFE22A7E8CEF45A3DBD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_AA4E9DFFC6D2C21238ACE8CEF45A6109" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_83D6B7B6187A3AFE22A7E8CEF45A3DBD" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_AA4E9DFFC6D2C21238ACE8CEF45A6109" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_F19241883E2107C9667FE8CEF45A8731" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_83D6B7B6187A3AFE22A7E8CEF45A3DBD" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_F19241883E2107C9667FE8CEF45A8731" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_B6C5F615C02AC6E0D5E3E8CEF45BD67E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_83D6B7B6187A3AFE22A7E8CEF45A3DBD" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_B6C5F615C02AC6E0D5E3E8CEF45BD67E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_A4B3484962E90E21BA4FE8CEF45B0D13" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_83D6B7B6187A3AFE22A7E8CEF45A3DBD" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_A4B3484962E90E21BA4FE8CEF45B0D13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_86A3A5CA803DB7FA69BCE8CEF45C493A" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_83D6B7B6187A3AFE22A7E8CEF45A3DBD" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_86A3A5CA803DB7FA69BCE8CEF45C493A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_D20982EF4187BA0D7F20E8CEF45C2047" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_86A3A5CA803DB7FA69BCE8CEF45C493A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_D20982EF4187BA0D7F20E8CEF45C2047" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_386251F9C417B34304A9E8CEF45C21C1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_86A3A5CA803DB7FA69BCE8CEF45C493A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_386251F9C417B34304A9E8CEF45C21C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_85CED589FA224F988D45E8CEF45C03F9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_86A3A5CA803DB7FA69BCE8CEF45C493A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_85CED589FA224F988D45E8CEF45C03F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_5BEB12E95E898C62EA7AE8CEF45D5842" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_86A3A5CA803DB7FA69BCE8CEF45C493A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_5BEB12E95E898C62EA7AE8CEF45D5842" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_40CF550FE0ACC1D321FBE8CEF45D1C23" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_40CF550FE0ACC1D321FBE8CEF45D1C23" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_8C200E9A084B9F5D7D08E8CEF45EC203" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_8C200E9A084B9F5D7D08E8CEF45EC203" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_SharebasedCompensation.SettlementRatioCommonSharesPerPSU" xlink:label="loc_noa_SharebasedCompensation.SettlementRatioCommonSharesPerPSU_80B0AC5C068A080EE671E8CEF45E1304" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_noa_SharebasedCompensation.SettlementRatioCommonSharesPerPSU_80B0AC5C068A080EE671E8CEF45E1304" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A9CDAE5EAB19EA73BA2EE8CEF45EAD95" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A9CDAE5EAB19EA73BA2EE8CEF45EAD95" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_A9A1F4B0207896AF6F72E8CEF45E1A43" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A9CDAE5EAB19EA73BA2EE8CEF45EAD95" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_A9A1F4B0207896AF6F72E8CEF45E1A43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_2BD7843EAAF2DA2D9E72E8CEF45FAE02" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A9CDAE5EAB19EA73BA2EE8CEF45EAD95" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_2BD7843EAAF2DA2D9E72E8CEF45FAE02" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPercentageOfNonOfficerDirectorCompensationPaidInFormOfDeferredStockUnits" xlink:label="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPercentageOfNonOfficerDirectorCompensationPaidInFormOfDeferredStockUnits_AE5DFA9EF0231FE7F65AE8CEF45F594C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPercentageOfNonOfficerDirectorCompensationPaidInFormOfDeferredStockUnits_AE5DFA9EF0231FE7F65AE8CEF45F594C" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_PercentageOfAnnualBonusEligibleForDeferredStockUnits" xlink:label="loc_noa_PercentageOfAnnualBonusEligibleForDeferredStockUnits_D0344CC5301128FB6113E8CEF45FB2EF" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_noa_PercentageOfAnnualBonusEligibleForDeferredStockUnits_D0344CC5301128FB6113E8CEF45FB2EF" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingFairValuePerShare" xlink:label="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingFairValuePerShare_3E3D799A0596F61364D2E8CEF460A715" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingFairValuePerShare_3E3D799A0596F61364D2E8CEF460A715" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent" xlink:label="loc_us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent_89F3262A5BC6E2E87D52E8CEF460F095" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent_89F3262A5BC6E2E87D52E8CEF460F095" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent" xlink:label="loc_us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent_B229C9114ABA89EA87ACE8CEF460D7AB" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent_B229C9114ABA89EA87ACE8CEF460D7AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards_3F5233DB47E9AEAB3D0BE8CEF460F30F" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E0DB8B8D85CBC9F68BC3E8CEF4596F53" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards_3F5233DB47E9AEAB3D0BE8CEF460F30F" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/StockBasedCompensationRestrictedShareUnitPlanDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8C79226B0A66B82FEB2AE46940FAFE79" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F18415CD9BB00B2A005DE46940F805DC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8C79226B0A66B82FEB2AE46940FAFE79" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F18415CD9BB00B2A005DE46940F805DC" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_BB9CFF9FA20BCA963397E46940F9E11D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F18415CD9BB00B2A005DE46940F805DC" xlink:to="loc_us-gaap_PlanNameAxis_BB9CFF9FA20BCA963397E46940F9E11D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_5740F5123B921D2B511FE46940F98BA9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_BB9CFF9FA20BCA963397E46940F9E11D" xlink:to="loc_us-gaap_PlanNameDomain_5740F5123B921D2B511FE46940F98BA9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_5740F5123B921D2B511FE46940F98BA9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_BB9CFF9FA20BCA963397E46940F9E11D" xlink:to="loc_us-gaap_PlanNameDomain_5740F5123B921D2B511FE46940F98BA9" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_LiabilityClassifiedRestrictedShareUnitPlanMember" xlink:label="loc_noa_LiabilityClassifiedRestrictedShareUnitPlanMember_03072780AB69613AC4E0E46940F9F918" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_5740F5123B921D2B511FE46940F98BA9" xlink:to="loc_noa_LiabilityClassifiedRestrictedShareUnitPlanMember_03072780AB69613AC4E0E46940F9F918" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_EquityClassifiedRestrictedShareUnitPlanMember" xlink:label="loc_noa_EquityClassifiedRestrictedShareUnitPlanMember_0179C88743EE65653FFEE46940F9F975" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_5740F5123B921D2B511FE46940F98BA9" xlink:to="loc_noa_EquityClassifiedRestrictedShareUnitPlanMember_0179C88743EE65653FFEE46940F9F975" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_84C1193BE4FA71DC627EE46940FA0737" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_F18415CD9BB00B2A005DE46940F805DC" xlink:to="loc_us-gaap_AwardTypeAxis_84C1193BE4FA71DC627EE46940FA0737" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0367BF59C75C093C2D4E46940FA1FF3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_84C1193BE4FA71DC627EE46940FA0737" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0367BF59C75C093C2D4E46940FA1FF3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0367BF59C75C093C2D4E46940FA1FF3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_84C1193BE4FA71DC627EE46940FA0737" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0367BF59C75C093C2D4E46940FA1FF3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_252E29CB46AF5FAAA5F6E46940FA58BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0367BF59C75C093C2D4E46940FA1FF3" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_252E29CB46AF5FAAA5F6E46940FA58BE" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodSubsequentToYearOfGrant" xlink:label="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodSubsequentToYearOfGrant_1C54FBAFA950E3D5ECC7E46940FBBE70" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8C79226B0A66B82FEB2AE46940FAFE79" xlink:to="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodSubsequentToYearOfGrant_1C54FBAFA950E3D5ECC7E46940FBBE70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_455DC69ADC0409C316B5E46940FBBC81" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8C79226B0A66B82FEB2AE46940FAFE79" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_455DC69ADC0409C316B5E46940FBBC81" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_007A0B283EBED028152FE46940FBD6E5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8C79226B0A66B82FEB2AE46940FAFE79" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_007A0B283EBED028152FE46940FBD6E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_2F71A3ECAF55EFBF9CC2E46940FB3479" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_007A0B283EBED028152FE46940FBD6E5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_2F71A3ECAF55EFBF9CC2E46940FB3479" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_073A3C7E74A676711830E46940FBE4F9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_007A0B283EBED028152FE46940FBD6E5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_073A3C7E74A676711830E46940FBE4F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_172200A0608A15EC4F0FE46940FCAF07" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_007A0B283EBED028152FE46940FBD6E5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_172200A0608A15EC4F0FE46940FCAF07" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_CB07AC6A32EC3860010CE46940FC4276" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_007A0B283EBED028152FE46940FBD6E5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_CB07AC6A32EC3860010CE46940FC4276" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_14413324BBEB4FB736E4E46940FC2CA9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8C79226B0A66B82FEB2AE46940FAFE79" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_14413324BBEB4FB736E4E46940FC2CA9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_95B297CBFCA334677079E46940FC2713" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_14413324BBEB4FB736E4E46940FC2CA9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_95B297CBFCA334677079E46940FC2713" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_3AB5385A6087568474B8E46940FDF9C6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_14413324BBEB4FB736E4E46940FC2CA9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_3AB5385A6087568474B8E46940FDF9C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_8437A535809AB36854AFE46940FDBAD5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_14413324BBEB4FB736E4E46940FC2CA9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_8437A535809AB36854AFE46940FDBAD5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_2669DFBF17FE16D82493E46940FD9896" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_14413324BBEB4FB736E4E46940FC2CA9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_2669DFBF17FE16D82493E46940FD9896" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_6B03227B3F9C7FFA3A1FE46940FE62E4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8C79226B0A66B82FEB2AE46940FAFE79" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_6B03227B3F9C7FFA3A1FE46940FE62E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_E49761EF2CF3B68BB5CDE46940FE361C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8C79226B0A66B82FEB2AE46940FAFE79" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_E49761EF2CF3B68BB5CDE46940FE361C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/StockBasedCompensationShareOptionsPlanDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0D8850913B8F81A2D2221696767C292D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0D8850913B8F81A2D2221696767C292D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_E15D189BCE33E0B673171696767DCF16" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0D8850913B8F81A2D2221696767C292D" xlink:to="loc_us-gaap_PlanNameAxis_E15D189BCE33E0B673171696767DCF16" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_8CD0B2C40824B3107F9C1696767DEB89_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_E15D189BCE33E0B673171696767DCF16" xlink:to="loc_us-gaap_PlanNameDomain_8CD0B2C40824B3107F9C1696767DEB89_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_8CD0B2C40824B3107F9C1696767DEB89" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_E15D189BCE33E0B673171696767DCF16" xlink:to="loc_us-gaap_PlanNameDomain_8CD0B2C40824B3107F9C1696767DEB89" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareOptionPlanMember" xlink:label="loc_noa_ShareOptionPlanMember_EAD169CD610EF3F5FF9E1696767DA97D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_8CD0B2C40824B3107F9C1696767DEB89" xlink:to="loc_noa_ShareOptionPlanMember_EAD169CD610EF3F5FF9E1696767DA97D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_56095D3CAF480239CF9E1696767E5B7B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0D8850913B8F81A2D2221696767C292D" xlink:to="loc_us-gaap_AwardTypeAxis_56095D3CAF480239CF9E1696767E5B7B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AC75AAE0A444426A7B831696767EC413_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_56095D3CAF480239CF9E1696767E5B7B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AC75AAE0A444426A7B831696767EC413_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AC75AAE0A444426A7B831696767EC413" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_56095D3CAF480239CF9E1696767E5B7B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AC75AAE0A444426A7B831696767EC413" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_EC9686A513E09E2D9C161696767ECE55" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AC75AAE0A444426A7B831696767EC413" xlink:to="loc_us-gaap_EmployeeStockOptionMember_EC9686A513E09E2D9C161696767ECE55" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_032DB8C96175A757A1E41696767F7956" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_032DB8C96175A757A1E41696767F7956" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNumberOfCommonSharesAwardedPerEachOptionExercised" xlink:label="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNumberOfCommonSharesAwardedPerEachOptionExercised_967D44D3A8B947B3ED701696767FB366" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNumberOfCommonSharesAwardedPerEachOptionExercised_967D44D3A8B947B3ED701696767FB366" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_197A4AAC1E644BB6D7A71696767FCBC7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_197A4AAC1E644BB6D7A71696767FCBC7" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAnnualVestingPercentage" xlink:label="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAnnualVestingPercentage_627B2260FA94AA2B2A1D1696767FB851" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAnnualVestingPercentage_627B2260FA94AA2B2A1D1696767FB851" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_A950AAC9959A6A8731361696767F9F82" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_A950AAC9959A6A8731361696767F9F82" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9A4BB653DE641A702697169676804F71" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9A4BB653DE641A702697169676804F71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_2016030F8FBDD11035BE16967680B936" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9A4BB653DE641A702697169676804F71" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_2016030F8FBDD11035BE16967680B936" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_B9637BCD433181FFF294169676808B52" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9A4BB653DE641A702697169676804F71" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_B9637BCD433181FFF294169676808B52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_CFA26D7E839F4E55DD5C16967680DFD0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9A4BB653DE641A702697169676804F71" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_CFA26D7E839F4E55DD5C16967680DFD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_3C883F730CC4736A3F61169676815D42" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_3C883F730CC4736A3F61169676815D42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_EF120F751FD63BCCB8561696768185FE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_3C883F730CC4736A3F61169676815D42" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_EF120F751FD63BCCB8561696768185FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_A5CCF1AB538BF7343557169676817082" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_3C883F730CC4736A3F61169676815D42" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_A5CCF1AB538BF7343557169676817082" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_9C686E600BC97AB3396116967681F2EB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_3C883F730CC4736A3F61169676815D42" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_9C686E600BC97AB3396116967681F2EB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_5487622D1055E015C2E816967682AC4C" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_5487622D1055E015C2E816967682AC4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_2831BA501357979F6A23169676829655" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CE9CABD62D863D253CA21696767E0EF4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_2831BA501357979F6A23169676829655" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/StockBasedCompensationStockBasedCompensationExpensesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_C923DC1D2C1CE5AAF4AEE469412AC8E7" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_875726D627CA2C33965AE46941274AC4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_C923DC1D2C1CE5AAF4AEE469412AC8E7" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_875726D627CA2C33965AE46941274AC4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_0B70500C16529E90B336E4694127E11B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_875726D627CA2C33965AE46941274AC4" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_0B70500C16529E90B336E4694127E11B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_0592B3587C5F0184E136E4694127BF43_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_0B70500C16529E90B336E4694127E11B" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_0592B3587C5F0184E136E4694127BF43_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_0592B3587C5F0184E136E4694127BF43" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_0B70500C16529E90B336E4694127E11B" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_0592B3587C5F0184E136E4694127BF43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_5915EA7B3C02405D692BE46941283E5B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_0592B3587C5F0184E136E4694127BF43" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_5915EA7B3C02405D692BE46941283E5B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_CD91292CBF61FBBC0B91E469412862F6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_875726D627CA2C33965AE46941274AC4" xlink:to="loc_us-gaap_PlanNameAxis_CD91292CBF61FBBC0B91E469412862F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_74E2A138C14B5BE6D272E46941288F54_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_CD91292CBF61FBBC0B91E469412862F6" xlink:to="loc_us-gaap_PlanNameDomain_74E2A138C14B5BE6D272E46941288F54_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_74E2A138C14B5BE6D272E46941288F54" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_CD91292CBF61FBBC0B91E469412862F6" xlink:to="loc_us-gaap_PlanNameDomain_74E2A138C14B5BE6D272E46941288F54" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_ShareOptionPlanMember" xlink:label="loc_noa_ShareOptionPlanMember_ED1EDED3E8DCCF2B813BE4694129898C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_74E2A138C14B5BE6D272E46941288F54" xlink:to="loc_noa_ShareOptionPlanMember_ED1EDED3E8DCCF2B813BE4694129898C" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_EquityClassifiedRestrictedShareUnitPlanMember" xlink:label="loc_noa_EquityClassifiedRestrictedShareUnitPlanMember_29E4EFC6AB0BB02B4286E4694129544D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_74E2A138C14B5BE6D272E46941288F54" xlink:to="loc_noa_EquityClassifiedRestrictedShareUnitPlanMember_29E4EFC6AB0BB02B4286E4694129544D" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_PerformanceRestrictedShareUnitPlanMember" xlink:label="loc_noa_PerformanceRestrictedShareUnitPlanMember_36E6CB516AB571E687E6E469412AEE30" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_74E2A138C14B5BE6D272E46941288F54" xlink:to="loc_noa_PerformanceRestrictedShareUnitPlanMember_36E6CB516AB571E687E6E469412AEE30" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_LiabilityClassifiedDeferredStockUnitPlanMember" xlink:label="loc_noa_LiabilityClassifiedDeferredStockUnitPlanMember_0DA2722FA53681FDB707E469412A51D6" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_74E2A138C14B5BE6D272E46941288F54" xlink:to="loc_noa_LiabilityClassifiedDeferredStockUnitPlanMember_0DA2722FA53681FDB707E469412A51D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_9D93CC7E67031EF7A781E469412A7EF8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_C923DC1D2C1CE5AAF4AEE469412AC8E7" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_9D93CC7E67031EF7A781E469412A7EF8" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.nacg.ca/role/StockBasedCompensationTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E698AB7AE33FE48E2D6EE46941327BF8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_D8BF2F906B06A5527A1AE4694130B60B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E698AB7AE33FE48E2D6EE46941327BF8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_D8BF2F906B06A5527A1AE4694130B60B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_EBE44FFE58B8B822912EE4694130DD16" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_D8BF2F906B06A5527A1AE4694130B60B" xlink:to="loc_us-gaap_PlanNameAxis_EBE44FFE58B8B822912EE4694130DD16" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_420EE8BC4C0608A53865E46941318A56_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_EBE44FFE58B8B822912EE4694130DD16" xlink:to="loc_us-gaap_PlanNameDomain_420EE8BC4C0608A53865E46941318A56_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_420EE8BC4C0608A53865E46941318A56" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_EBE44FFE58B8B822912EE4694130DD16" xlink:to="loc_us-gaap_PlanNameDomain_420EE8BC4C0608A53865E46941318A56" xlink:type="arc" />
    <link:loc xlink:href="noa-20181231.xsd#noa_EquityClassifiedRestrictedShareUnitPlanMember" xlink:label="loc_noa_EquityClassifiedRestrictedShareUnitPlanMember_B3270A03E1D156104C76E46941319CA6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_420EE8BC4C0608A53865E46941318A56" xlink:to="loc_noa_EquityClassifiedRestrictedShareUnitPlanMember_B3270A03E1D156104C76E46941319CA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_49566889610174AB3101E46941325CA6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E698AB7AE33FE48E2D6EE46941327BF8" xlink:to="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_49566889610174AB3101E46941325CA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_15002758050B9417699CE46941322EC3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E698AB7AE33FE48E2D6EE46941327BF8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_15002758050B9417699CE46941322EC3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTextBlock" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTextBlock_9339107696626F14E012E46941325F6E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E698AB7AE33FE48E2D6EE46941327BF8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTextBlock_9339107696626F14E012E46941325F6E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_168935F79B57037F3CEBE46941324B66" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E698AB7AE33FE48E2D6EE46941327BF8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_168935F79B57037F3CEBE46941324B66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock_5972151BDA8719601B0CE4694133D16C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E698AB7AE33FE48E2D6EE46941327BF8" xlink:to="loc_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock_5972151BDA8719601B0CE4694133D16C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_D9FD9D07D48714B032D3E46941333678" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E698AB7AE33FE48E2D6EE46941327BF8" xlink:to="loc_us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_D9FD9D07D48714B032D3E46941333678" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock_689AFF7F33A383DA7B14E4694133881C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_E698AB7AE33FE48E2D6EE46941327BF8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock_689AFF7F33A383DA7B14E4694133881C" xlink:type="arc" />
  </link:definitionLink>
</link:linkbase>
