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    <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" />
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    <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" />
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    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792_label_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract_86619E811649ABC672FECF7EF661F792" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]</link:label>
    <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" />
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    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent_1776B8768B988FD7860DCF7EF6628619_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent_1776B8768B988FD7860DCF7EF6628619" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2019</link:label>
    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent_1776B8768B988FD7860DCF7EF6628619_label_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent_1776B8768B988FD7860DCF7EF6628619" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital Leases, Future Minimum Payments Due, Next Twelve Months</link:label>
    <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" />
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    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_D1C51E86A66B5686F57CCF7EF662343A_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_D1C51E86A66B5686F57CCF7EF662343A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2020</link:label>
    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_D1C51E86A66B5686F57CCF7EF662343A_label_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_D1C51E86A66B5686F57CCF7EF662343A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital Leases, Future Minimum Payments Due in Two Years</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_D1C51E86A66B5686F57CCF7EF662343A" xlink:to="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears_D1C51E86A66B5686F57CCF7EF662343A" xlink:type="arc" />
    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_A641DCB83096AE40D029CF7EF66279DE_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_A641DCB83096AE40D029CF7EF66279DE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2021</link:label>
    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_A641DCB83096AE40D029CF7EF66279DE_label_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears_A641DCB83096AE40D029CF7EF66279DE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital Leases, Future Minimum Payments Due in Three Years</link:label>
    <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" />
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    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears_764A8AF2DF031D2462ADCF7EF66224A4_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears_764A8AF2DF031D2462ADCF7EF66224A4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022</link:label>
    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears_764A8AF2DF031D2462ADCF7EF66224A4_label_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears_764A8AF2DF031D2462ADCF7EF66224A4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital Leases, Future Minimum Payments Due in Four Years</link:label>
    <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" />
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    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears_2A75184BEDAD30335110CF7EF66201CE_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears_2A75184BEDAD30335110CF7EF66201CE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2023</link:label>
    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears_2A75184BEDAD30335110CF7EF66201CE_label_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears_2A75184BEDAD30335110CF7EF66201CE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital Leases, Future Minimum Payments Due in Five Years</link:label>
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    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_2FE2A27E488B0FB0B529CF7EF6635E45_totalLabel_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_2FE2A27E488B0FB0B529CF7EF6635E45" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Subtotal:</link:label>
    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_2FE2A27E488B0FB0B529CF7EF6635E45_label_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsDue_2FE2A27E488B0FB0B529CF7EF6635E45" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capital Leases, Future Minimum Payments Due</link:label>
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    <link:label id="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments_B4AA10001AB7051BD9F1CF7EF66320D2_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments_B4AA10001AB7051BD9F1CF7EF66320D2" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Less: amount representing interest (at rates ranging from 2.48% to 7.51%)</link:label>
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    <link:label id="lab_us-gaap_CapitalLeaseObligationsCurrent_43F9CC7783A894CC7BFBCF7EF663488F_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_CapitalLeaseObligationsCurrent_43F9CC7783A894CC7BFBCF7EF663488F" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Less: current portion</link:label>
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    <link:label id="lab_us-gaap_CapitalizedContractCostTable_9A076660D95DFF404FB51696770EF14E_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostTable_9A076660D95DFF404FB51696770EF14E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capitalized Contract Cost [Table]</link:label>
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    <link:label id="lab_us-gaap_CapitalizedContractCostAxis_B6CA19320D9D467B967D1696770FD107_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostAxis_B6CA19320D9D467B967D1696770FD107" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capitalized Contract Cost [Axis]</link:label>
    <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" />
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    <link:label id="lab_us-gaap_CapitalizedContractCostDomain_947C2DAB6D6B95D03C541696770F1FF0_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostDomain_947C2DAB6D6B95D03C541696770F1FF0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capitalized Contract Cost [Domain]</link:label>
    <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" />
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    <link:label id="lab_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523_terseLabel_en-US" xlink:label="lab_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reimbursable bid costs</link:label>
    <link:label id="lab_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523_label_en-US" xlink:label="lab_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capitalized Contract Cost - Reimbursable Bid Costs [Member]</link:label>
    <link:label id="lab_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523_documentation_en-US" xlink:label="lab_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Capitalized Contract Cost - Reimbursable Bid Costs [Member]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_CapitalizedContractCostReimbursableBidCostsMember" xlink:label="loc_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523" xlink:to="lab_noa_CapitalizedContractCostReimbursableBidCostsMember_AB5E719D5007DDCB3F9116967710C523" xlink:type="arc" />
    <link:label id="lab_noa_CapitalizedContractCostFulfillmentCostMember_7FF666D122AD29A4307416967710299C_terseLabel_en-US" xlink:label="lab_noa_CapitalizedContractCostFulfillmentCostMember_7FF666D122AD29A4307416967710299C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fulfillment costs</link:label>
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    <link:label id="lab_noa_CapitalizedContractCostFulfillmentCostMember_7FF666D122AD29A4307416967710299C_documentation_en-US" xlink:label="lab_noa_CapitalizedContractCostFulfillmentCostMember_7FF666D122AD29A4307416967710299C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Capitalized Contract Cost - Fulfillment Cost [Member]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_CapitalizedContractCostFulfillmentCostMember" xlink:label="loc_noa_CapitalizedContractCostFulfillmentCostMember_7FF666D122AD29A4307416967710299C" xlink:type="locator" />
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    <link:label id="lab_us-gaap_CapitalizedContractCostLineItems_EAD00AA14863930AECF6169677101E88_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostLineItems_EAD00AA14863930AECF6169677101E88" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capitalized Contract Cost [Line Items]</link:label>
    <link:label id="lab_us-gaap_CapitalizedContractCostLineItems_EAD00AA14863930AECF6169677101E88_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostLineItems_EAD00AA14863930AECF6169677101E88" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capitalized Contract Cost [Line Items]</link:label>
    <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" />
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    <link:label id="lab_us-gaap_CapitalizedContractCostNet_043244305E53B0B0F36E16967710B933_label_en-US" xlink:label="lab_us-gaap_CapitalizedContractCostNet_043244305E53B0B0F36E16967710B933" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Capitalized Contract Cost, Net</link:label>
    <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" />
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    <link:label id="lab_noa_CapitalizedContractCostAdditions_D0521CB3D79259CD474916967711E697_terseLabel_en-US" xlink:label="lab_noa_CapitalizedContractCostAdditions_D0521CB3D79259CD474916967711E697" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Contract costs capitalized during the period</link:label>
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    <link:label id="lab_noa_ContractwithCustomerAssetAccountsReceivableNetCurrent_995952F41481C687A41216967746F682_terseLabel_en-US" xlink:label="lab_noa_ContractwithCustomerAssetAccountsReceivableNetCurrent_995952F41481C687A41216967746F682" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Contract receivables, included in accounts receivable, net</link:label>
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    <link:label id="lab_noa_ContractwithCustomerAssetAccountsReceivableNetCurrent_995952F41481C687A41216967746F682_documentation_en-US" xlink:label="lab_noa_ContractwithCustomerAssetAccountsReceivableNetCurrent_995952F41481C687A41216967746F682" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Contract with Customer, Asset, Accounts Receivable, Net, Current</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerAssetCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress" xlink:label="loc_us-gaap_ContractWithCustomerAssetCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress_5DA91B2DF445EDB51E0216967747FFC8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerAssetCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress_5DA91B2DF445EDB51E0216967747FFC8" xlink:to="lab_us-gaap_ContractWithCustomerAssetCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress_5DA91B2DF445EDB51E0216967747FFC8" xlink:type="arc" />
    <link:label id="lab_noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted_226215C7EB6BB178745D16967747DEE7_terseLabel_en-US" xlink:label="lab_noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted_226215C7EB6BB178745D16967747DEE7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increases as a result of work completed, but not yet an unconditional right to consideration</link:label>
    <link:label id="lab_noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted_226215C7EB6BB178745D16967747DEE7_label_en-US" xlink:label="lab_noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted_226215C7EB6BB178745D16967747DEE7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contract with Customer, Asset, Increase Due to Work Completed</link:label>
    <link:label id="lab_noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted_226215C7EB6BB178745D16967747DEE7_documentation_en-US" xlink:label="lab_noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted_226215C7EB6BB178745D16967747DEE7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Contract with Customer, Asset, Increase Due to Work Completed</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted" xlink:label="loc_noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted_226215C7EB6BB178745D16967747DEE7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted_226215C7EB6BB178745D16967747DEE7" xlink:to="lab_noa_ContractwithCustomerAssetIncreaseDuetoWorkCompleted_226215C7EB6BB178745D16967747DEE7" xlink:type="arc" />
    <link:label id="lab_us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_4DDF6AC227BA65F20725169677474DE5_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_4DDF6AC227BA65F20725169677474DE5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increases as a result of Nuna acquisition</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_4DDF6AC227BA65F20725169677474DE5_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_4DDF6AC227BA65F20725169677474DE5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contract with Customer, Asset, Increase (Decrease) for Contract Acquired in Business Combination</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination" xlink:label="loc_us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_4DDF6AC227BA65F20725169677474DE5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_4DDF6AC227BA65F20725169677474DE5" xlink:to="lab_us-gaap_ContractWithCustomerAssetIncreaseDecreaseForContractAcquiredInBusinessCombination_4DDF6AC227BA65F20725169677474DE5" xlink:type="arc" />
    <link:label id="lab_us-gaap_ChangeInContractWithCustomerLiabilityAbstract_4612391644AC6198856D16967747D022_terseLabel_en-US" xlink:label="lab_us-gaap_ChangeInContractWithCustomerLiabilityAbstract_4612391644AC6198856D16967747D022" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Significant Changes in Contract Liabilities</link:label>
    <link:label id="lab_us-gaap_ChangeInContractWithCustomerLiabilityAbstract_4612391644AC6198856D16967747D022_label_en-US" xlink:label="lab_us-gaap_ChangeInContractWithCustomerLiabilityAbstract_4612391644AC6198856D16967747D022" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Change in Contract with Customer, Liability [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ChangeInContractWithCustomerLiabilityAbstract" xlink:label="loc_us-gaap_ChangeInContractWithCustomerLiabilityAbstract_4612391644AC6198856D16967747D022" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ChangeInContractWithCustomerLiabilityAbstract_4612391644AC6198856D16967747D022" xlink:to="lab_us-gaap_ChangeInContractWithCustomerLiabilityAbstract_4612391644AC6198856D16967747D022" xlink:type="arc" />
    <link:label id="lab_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_8353EACBC77026FDE32B169677480250_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_8353EACBC77026FDE32B169677480250" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue recognized that was included in the contract liability balance at the beginning of the period</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_8353EACBC77026FDE32B169677480250_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_8353EACBC77026FDE32B169677480250" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contract with Customer, Liability, Revenue Recognized</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_8353EACBC77026FDE32B169677480250" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_8353EACBC77026FDE32B169677480250" xlink:to="lab_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_8353EACBC77026FDE32B169677480250" xlink:type="arc" />
    <link:label id="lab_noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts_760E852116F70D465F0816967748A7F7_terseLabel_en-US" xlink:label="lab_noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts_760E852116F70D465F0816967748A7F7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increases due to cash received, excluding amounts recognized as revenue during the period</link:label>
    <link:label id="lab_noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts_760E852116F70D465F0816967748A7F7_label_en-US" xlink:label="lab_noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts_760E852116F70D465F0816967748A7F7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contract With Customer, Liability, Increase From Cash Receipts</link:label>
    <link:label id="lab_noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts_760E852116F70D465F0816967748A7F7_documentation_en-US" xlink:label="lab_noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts_760E852116F70D465F0816967748A7F7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Contract With Customer, Liability, Increase From Cash Receipts</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts" xlink:label="loc_noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts_760E852116F70D465F0816967748A7F7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts_760E852116F70D465F0816967748A7F7" xlink:to="lab_noa_ContractWithCustomerLiabilityIncreaseFromCashReceipts_760E852116F70D465F0816967748A7F7" xlink:type="arc" />
    <link:label id="lab_us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_63E5471589CAE5A2207E16967748035C_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_63E5471589CAE5A2207E16967748035C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increases as a result of Nuna acquisition</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_63E5471589CAE5A2207E16967748035C_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_63E5471589CAE5A2207E16967748035C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contract with Customer, Liability, Increase (Decrease) for Contract Acquired in Business Combination</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_63E5471589CAE5A2207E16967748035C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_63E5471589CAE5A2207E16967748035C" xlink:to="lab_us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_63E5471589CAE5A2207E16967748035C" xlink:type="arc" />
    <link:label id="lab_us-gaap_RevenuePerformanceObligationAbstract_D7F02C3CF84FCB4EBDB416967748E852_terseLabel_en-US" xlink:label="lab_us-gaap_RevenuePerformanceObligationAbstract_D7F02C3CF84FCB4EBDB416967748E852" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Performance Obligation</link:label>
    <link:label id="lab_us-gaap_RevenuePerformanceObligationAbstract_D7F02C3CF84FCB4EBDB416967748E852_label_en-US" xlink:label="lab_us-gaap_RevenuePerformanceObligationAbstract_D7F02C3CF84FCB4EBDB416967748E852" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Performance Obligation [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenuePerformanceObligationAbstract" xlink:label="loc_us-gaap_RevenuePerformanceObligationAbstract_D7F02C3CF84FCB4EBDB416967748E852" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenuePerformanceObligationAbstract_D7F02C3CF84FCB4EBDB416967748E852" xlink:to="lab_us-gaap_RevenuePerformanceObligationAbstract_D7F02C3CF84FCB4EBDB416967748E852" xlink:type="arc" />
    <link:label id="lab_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_2E725EF8EDB43ECB56C61696774956F5_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_2E725EF8EDB43ECB56C61696774956F5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue recognized</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_2E725EF8EDB43ECB56C61696774956F5_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_2E725EF8EDB43ECB56C61696774956F5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contract with Customer, Performance Obligation Satisfied in Previous Period</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod" xlink:label="loc_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_2E725EF8EDB43ECB56C61696774956F5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_2E725EF8EDB43ECB56C61696774956F5" xlink:to="lab_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_2E725EF8EDB43ECB56C61696774956F5" xlink:type="arc" />
    <link:label id="lab_us-gaap_StatementOfFinancialPositionAbstract_2F60EC5C6F6AE3091B9224FE0BD05D79_label_en-US" xlink:label="lab_us-gaap_StatementOfFinancialPositionAbstract_2F60EC5C6F6AE3091B9224FE0BD05D79" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Financial Position [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_2F60EC5C6F6AE3091B9224FE0BD05D79" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_2F60EC5C6F6AE3091B9224FE0BD05D79" xlink:to="lab_us-gaap_StatementOfFinancialPositionAbstract_2F60EC5C6F6AE3091B9224FE0BD05D79" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsAbstract_025334129B60112CE86E24FE0BD0CB65_verboseLabel_en-US" xlink:label="lab_us-gaap_AssetsAbstract_025334129B60112CE86E24FE0BD0CB65" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Assets</link:label>
    <link:label id="lab_us-gaap_AssetsAbstract_025334129B60112CE86E24FE0BD0CB65_label_en-US" xlink:label="lab_us-gaap_AssetsAbstract_025334129B60112CE86E24FE0BD0CB65" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets [Abstract]</link:label>
    <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_025334129B60112CE86E24FE0BD0CB65" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsAbstract_025334129B60112CE86E24FE0BD0CB65" xlink:to="lab_us-gaap_AssetsAbstract_025334129B60112CE86E24FE0BD0CB65" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsCurrentAbstract_7F2FCA50D5CBBB857CC424FE0BD030D6_verboseLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrentAbstract_7F2FCA50D5CBBB857CC424FE0BD030D6" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Current assets</link:label>
    <link:label id="lab_us-gaap_AssetsCurrentAbstract_7F2FCA50D5CBBB857CC424FE0BD030D6_label_en-US" xlink:label="lab_us-gaap_AssetsCurrentAbstract_7F2FCA50D5CBBB857CC424FE0BD030D6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets, Current [Abstract]</link:label>
    <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_7F2FCA50D5CBBB857CC424FE0BD030D6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrentAbstract_7F2FCA50D5CBBB857CC424FE0BD030D6" xlink:to="lab_us-gaap_AssetsCurrentAbstract_7F2FCA50D5CBBB857CC424FE0BD030D6" xlink:type="arc" />
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_EF53147224ACCFA5454624FE0BD11ECC_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_EF53147224ACCFA5454624FE0BD11ECC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_EF53147224ACCFA5454624FE0BD11ECC_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_EF53147224ACCFA5454624FE0BD11ECC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, at Carrying Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_EF53147224ACCFA5454624FE0BD11ECC" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent_1CEFBB63A4199D300D3C24FE0BD1B7B8_verboseLabel_en-US" xlink:label="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent_1CEFBB63A4199D300D3C24FE0BD1B7B8" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable, net (notes 6 and 19(c))</link:label>
    <link:label id="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent_1CEFBB63A4199D300D3C24FE0BD1B7B8_label_en-US" xlink:label="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent_1CEFBB63A4199D300D3C24FE0BD1B7B8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts and Other Receivables, Net, Current</link:label>
    <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_1CEFBB63A4199D300D3C24FE0BD1B7B8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsAndOtherReceivablesNetCurrent_1CEFBB63A4199D300D3C24FE0BD1B7B8" xlink:to="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent_1CEFBB63A4199D300D3C24FE0BD1B7B8" xlink:type="arc" />
    <link:label id="lab_us-gaap_ContractWithCustomerAssetNetCurrent_7B7FDD886803EAB127FF24FE0BD1FC18_verboseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetNetCurrent_7B7FDD886803EAB127FF24FE0BD1FC18" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Contract assets (note 19(c))</link:label>
    <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_7B7FDD886803EAB127FF24FE0BD1FC18" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerAssetNetCurrent_7B7FDD886803EAB127FF24FE0BD1FC18" xlink:to="lab_us-gaap_ContractWithCustomerAssetNetCurrent_7B7FDD886803EAB127FF24FE0BD1FC18" xlink:type="arc" />
    <link:label id="lab_us-gaap_InventoryNet_C3BC9BE79BD2406D776124FE0BD15C5B_verboseLabel_en-US" xlink:label="lab_us-gaap_InventoryNet_C3BC9BE79BD2406D776124FE0BD15C5B" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Inventories</link:label>
    <link:label id="lab_us-gaap_InventoryNet_C3BC9BE79BD2406D776124FE0BD15C5B_label_en-US" xlink:label="lab_us-gaap_InventoryNet_C3BC9BE79BD2406D776124FE0BD15C5B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Inventory, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_C3BC9BE79BD2406D776124FE0BD15C5B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryNet_C3BC9BE79BD2406D776124FE0BD15C5B" xlink:to="lab_us-gaap_InventoryNet_C3BC9BE79BD2406D776124FE0BD15C5B" xlink:type="arc" />
    <link:label id="lab_us-gaap_PrepaidExpenseCurrent_769670678DB2E82B303C24FE0BD2EAFD_terseLabel_en-US" xlink:label="lab_us-gaap_PrepaidExpenseCurrent_769670678DB2E82B303C24FE0BD2EAFD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prepaid expenses and deposits (note 7)</link:label>
    <link:label id="lab_us-gaap_PrepaidExpenseCurrent_769670678DB2E82B303C24FE0BD2EAFD_label_en-US" xlink:label="lab_us-gaap_PrepaidExpenseCurrent_769670678DB2E82B303C24FE0BD2EAFD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prepaid Expense, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PrepaidExpenseCurrent" xlink:label="loc_us-gaap_PrepaidExpenseCurrent_769670678DB2E82B303C24FE0BD2EAFD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PrepaidExpenseCurrent_769670678DB2E82B303C24FE0BD2EAFD" xlink:to="lab_us-gaap_PrepaidExpenseCurrent_769670678DB2E82B303C24FE0BD2EAFD" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent_1691F49D4B95CBAE2CE524FE0BD29485_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent_1691F49D4B95CBAE2CE524FE0BD29485" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets held for sale (notes 8 and 16(a))</link:label>
    <link:label id="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent_1691F49D4B95CBAE2CE524FE0BD29485_label_en-US" xlink:label="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent_1691F49D4B95CBAE2CE524FE0BD29485" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Current</link:label>
    <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_1691F49D4B95CBAE2CE524FE0BD29485" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent_1691F49D4B95CBAE2CE524FE0BD29485" xlink:to="lab_us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent_1691F49D4B95CBAE2CE524FE0BD29485" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsCurrent_D82DD5E2D76A42051D2724FE0BD2C571_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrent_D82DD5E2D76A42051D2724FE0BD2C571" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total current assets</link:label>
    <link:label id="lab_us-gaap_AssetsCurrent_D82DD5E2D76A42051D2724FE0BD2C571_label_en-US" xlink:label="lab_us-gaap_AssetsCurrent_D82DD5E2D76A42051D2724FE0BD2C571" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets, Current</link:label>
    <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_D82DD5E2D76A42051D2724FE0BD2C571" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrent_D82DD5E2D76A42051D2724FE0BD2C571" xlink:to="lab_us-gaap_AssetsCurrent_D82DD5E2D76A42051D2724FE0BD2C571" xlink:type="arc" />
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_EF70BCA48A04B2238F4724FE0BD28402_verboseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet_EF70BCA48A04B2238F4724FE0BD28402" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment, net of accumulated depreciation $248,885 (2017 &#8211; $220,320) (note 9)</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_EF70BCA48A04B2238F4724FE0BD28402_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet_EF70BCA48A04B2238F4724FE0BD28402" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Net</link:label>
    <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_EF70BCA48A04B2238F4724FE0BD28402" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_EF70BCA48A04B2238F4724FE0BD28402" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentNet_EF70BCA48A04B2238F4724FE0BD28402" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherAssetsNoncurrent_7F1CBB01B8ECC4E306E424FE0BD280B4_verboseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent_7F1CBB01B8ECC4E306E424FE0BD280B4" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Other assets (note 10)</link:label>
    <link:label id="lab_us-gaap_OtherAssetsNoncurrent_7F1CBB01B8ECC4E306E424FE0BD280B4_label_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent_7F1CBB01B8ECC4E306E424FE0BD280B4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Assets, Noncurrent</link:label>
    <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_7F1CBB01B8ECC4E306E424FE0BD280B4" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsNoncurrent_7F1CBB01B8ECC4E306E424FE0BD280B4" xlink:to="lab_us-gaap_OtherAssetsNoncurrent_7F1CBB01B8ECC4E306E424FE0BD280B4" xlink:type="arc" />
    <link:label id="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_56CE5EE23EFDC83DFF3624FE0BD2DCA9_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_56CE5EE23EFDC83DFF3624FE0BD2DCA9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investments in affiliates and joint ventures (note 13(a))</link:label>
    <link:label id="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_56CE5EE23EFDC83DFF3624FE0BD2DCA9_label_en-US" xlink:label="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_56CE5EE23EFDC83DFF3624FE0BD2DCA9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures</link:label>
    <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_56CE5EE23EFDC83DFF3624FE0BD2DCA9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_56CE5EE23EFDC83DFF3624FE0BD2DCA9" xlink:to="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_56CE5EE23EFDC83DFF3624FE0BD2DCA9" xlink:type="arc" />
    <link:label id="lab_us-gaap_DeferredIncomeTaxAssetsNet_A9E5F1FB29DE08F0B7AB24FE0BD2AE21_verboseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxAssetsNet_A9E5F1FB29DE08F0B7AB24FE0BD2AE21" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Deferred tax assets (note 11)</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxAssetsNet_A9E5F1FB29DE08F0B7AB24FE0BD2AE21_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxAssetsNet_A9E5F1FB29DE08F0B7AB24FE0BD2AE21" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Income Tax Assets, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_A9E5F1FB29DE08F0B7AB24FE0BD2AE21" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeTaxAssetsNet_A9E5F1FB29DE08F0B7AB24FE0BD2AE21" xlink:to="lab_us-gaap_DeferredIncomeTaxAssetsNet_A9E5F1FB29DE08F0B7AB24FE0BD2AE21" xlink:type="arc" />
    <link:label id="lab_us-gaap_Assets_185ECDA09923F117564024FE0BD344FA_totalLabel_en-US" xlink:label="lab_us-gaap_Assets_185ECDA09923F117564024FE0BD344FA" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total Assets</link:label>
    <link:label id="lab_us-gaap_Assets_185ECDA09923F117564024FE0BD344FA_label_en-US" xlink:label="lab_us-gaap_Assets_185ECDA09923F117564024FE0BD344FA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets</link:label>
    <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_185ECDA09923F117564024FE0BD344FA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets_185ECDA09923F117564024FE0BD344FA" xlink:to="lab_us-gaap_Assets_185ECDA09923F117564024FE0BD344FA" xlink:type="arc" />
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C4543A0770909D920F3D24FE0BD3A520_verboseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C4543A0770909D920F3D24FE0BD3A520" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Liabilities and Shareholders' Equity</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C4543A0770909D920F3D24FE0BD3A520_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C4543A0770909D920F3D24FE0BD3A520" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities and Equity [Abstract]</link:label>
    <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_C4543A0770909D920F3D24FE0BD3A520" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C4543A0770909D920F3D24FE0BD3A520" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_C4543A0770909D920F3D24FE0BD3A520" xlink:type="arc" />
    <link:label id="lab_us-gaap_LiabilitiesCurrentAbstract_46380FF9ADFAACC0EFFB24FE0BD3E8DF_verboseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrentAbstract_46380FF9ADFAACC0EFFB24FE0BD3E8DF" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Current liabilities</link:label>
    <link:label id="lab_us-gaap_LiabilitiesCurrentAbstract_46380FF9ADFAACC0EFFB24FE0BD3E8DF_label_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrentAbstract_46380FF9ADFAACC0EFFB24FE0BD3E8DF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities, Current [Abstract]</link:label>
    <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_46380FF9ADFAACC0EFFB24FE0BD3E8DF" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_46380FF9ADFAACC0EFFB24FE0BD3E8DF" xlink:to="lab_us-gaap_LiabilitiesCurrentAbstract_46380FF9ADFAACC0EFFB24FE0BD3E8DF" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccountsPayableCurrent_1ECBA1FB4A1F1070C1BC24FE0BD39A3C_verboseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableCurrent_1ECBA1FB4A1F1070C1BC24FE0BD39A3C" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Accounts payable</link:label>
    <link:label id="lab_us-gaap_AccountsPayableCurrent_1ECBA1FB4A1F1070C1BC24FE0BD39A3C_label_en-US" xlink:label="lab_us-gaap_AccountsPayableCurrent_1ECBA1FB4A1F1070C1BC24FE0BD39A3C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Payable, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_1ECBA1FB4A1F1070C1BC24FE0BD39A3C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableCurrent_1ECBA1FB4A1F1070C1BC24FE0BD39A3C" xlink:to="lab_us-gaap_AccountsPayableCurrent_1ECBA1FB4A1F1070C1BC24FE0BD39A3C" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrent_26F3D290C9D25B22C64524FE0BD41B08_verboseLabel_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent_26F3D290C9D25B22C64524FE0BD41B08" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Accrued liabilities (note 12)</link:label>
    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrent_26F3D290C9D25B22C64524FE0BD41B08_label_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent_26F3D290C9D25B22C64524FE0BD41B08" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued Liabilities, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_26F3D290C9D25B22C64524FE0BD41B08" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrent_26F3D290C9D25B22C64524FE0BD41B08" xlink:to="lab_us-gaap_AccruedLiabilitiesCurrent_26F3D290C9D25B22C64524FE0BD41B08" xlink:type="arc" />
    <link:label id="lab_us-gaap_ContractWithCustomerLiabilityCurrent_D86CC8F048EE82B1749924FE0BD46D23_verboseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiabilityCurrent_D86CC8F048EE82B1749924FE0BD46D23" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Contract liabilities (note 19(c))</link:label>
    <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_D86CC8F048EE82B1749924FE0BD46D23" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LongTermDebtCurrent_42CA8ADB919E1FA2D1CF24FE0BD4D9B1_verboseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtCurrent_42CA8ADB919E1FA2D1CF24FE0BD4D9B1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Current portion of long term debt (note 14(a))</link:label>
    <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_42CA8ADB919E1FA2D1CF24FE0BD4D9B1" xlink:type="locator" />
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    <link:label id="lab_us-gaap_CapitalLeaseObligationsCurrent_45B228D537B673728AE524FE0BD4A8B6_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalLeaseObligationsCurrent_45B228D537B673728AE524FE0BD4A8B6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Current portion of capital lease obligations (note 15)</link:label>
    <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_45B228D537B673728AE524FE0BD4A8B6" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LiabilitiesCurrent_28AAB1E02F2BB7ECE3A424FE0BD4A554_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrent_28AAB1E02F2BB7ECE3A424FE0BD4A554" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total current liabilities</link:label>
    <link:label id="lab_us-gaap_LiabilitiesCurrent_28AAB1E02F2BB7ECE3A424FE0BD4A554_label_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrent_28AAB1E02F2BB7ECE3A424FE0BD4A554" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities, Current</link:label>
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    <link:label id="lab_us-gaap_LongTermDebtNoncurrent_18978E8BA3710C6FE63E24FE0BD4CC3E_verboseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent_18978E8BA3710C6FE63E24FE0BD4CC3E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Long term debt (note 14(a))</link:label>
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    <link:label id="lab_us-gaap_Liabilities_1E1634B314A2345BFCE424FE0BD5000A_label_en-US" xlink:label="lab_us-gaap_Liabilities_1E1634B314A2345BFCE424FE0BD5000A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities</link:label>
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    <link:label id="lab_us-gaap_TreasuryStockValue_7E0EA36CC8EBE7F9A79C24FE0BD6C3CC_label_en-US" xlink:label="lab_us-gaap_TreasuryStockValue_7E0EA36CC8EBE7F9A79C24FE0BD6C3CC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Treasury Stock, Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="loc_us-gaap_TreasuryStockValue_7E0EA36CC8EBE7F9A79C24FE0BD6C3CC" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital_A6A25F246BCD9902AF7124FE0BD69BB0" xlink:type="locator" />
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    <link:label id="lab_noa_Contingencies_FBA8924C8E05D5223BCC24FE0BD77BEA_label_en-US" xlink:label="lab_noa_Contingencies_FBA8924C8E05D5223BCC24FE0BD77BEA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contingencies</link:label>
    <link:label id="lab_noa_Contingencies_FBA8924C8E05D5223BCC24FE0BD77BEA_documentation_en-US" xlink:label="lab_noa_Contingencies_FBA8924C8E05D5223BCC24FE0BD77BEA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Contingencies.</link:label>
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    <link:label id="lab_us-gaap_ReceivablesAbstract_86225DCEC49F976EEEBB1D8C14CAAAB2_label_en-US" xlink:label="lab_us-gaap_ReceivablesAbstract_86225DCEC49F976EEEBB1D8C14CAAAB2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Receivables [Abstract]</link:label>
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    <link:label id="lab_us-gaap_AccountsReceivableGrossCurrent_035C55B92C44169FB7331D8C14CD7B66_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableGrossCurrent_035C55B92C44169FB7331D8C14CD7B66" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Trade</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsReceivableGrossCurrent" xlink:label="loc_us-gaap_AccountsReceivableGrossCurrent_035C55B92C44169FB7331D8C14CD7B66" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OtherReceivablesGrossCurrent_A53D225B1391F2AE7D091D8C14D10305_terseLabel_en-US" xlink:label="lab_us-gaap_OtherReceivablesGrossCurrent_A53D225B1391F2AE7D091D8C14D10305" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_OtherReceivablesGrossCurrent_A53D225B1391F2AE7D091D8C14D10305_label_en-US" xlink:label="lab_us-gaap_OtherReceivablesGrossCurrent_A53D225B1391F2AE7D091D8C14D10305" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Receivables, Gross, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherReceivablesGrossCurrent" xlink:label="loc_us-gaap_OtherReceivablesGrossCurrent_A53D225B1391F2AE7D091D8C14D10305" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherReceivablesGrossCurrent_A53D225B1391F2AE7D091D8C14D10305" xlink:to="lab_us-gaap_OtherReceivablesGrossCurrent_A53D225B1391F2AE7D091D8C14D10305" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent_64868248702E95F45B731D8C14D15A45_totalLabel_en-US" xlink:label="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent_64868248702E95F45B731D8C14D15A45" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total accounts receivable</link:label>
    <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_64868248702E95F45B731D8C14D15A45" xlink:type="locator" />
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    <link:label id="lab_noa_AccountsReceivableMaximumHoldbackPercentage_DF8A9AFE334388FE6A251D8C14D1B91A_terseLabel_en-US" xlink:label="lab_noa_AccountsReceivableMaximumHoldbackPercentage_DF8A9AFE334388FE6A251D8C14D1B91A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable &#8211; holdback percentage</link:label>
    <link:label id="lab_noa_AccountsReceivableMaximumHoldbackPercentage_DF8A9AFE334388FE6A251D8C14D1B91A_label_en-US" xlink:label="lab_noa_AccountsReceivableMaximumHoldbackPercentage_DF8A9AFE334388FE6A251D8C14D1B91A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Maximum Holdback Percentage</link:label>
    <link:label id="lab_noa_AccountsReceivableMaximumHoldbackPercentage_DF8A9AFE334388FE6A251D8C14D1B91A_documentation_en-US" xlink:label="lab_noa_AccountsReceivableMaximumHoldbackPercentage_DF8A9AFE334388FE6A251D8C14D1B91A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Maximum Holdback Percentage</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_AccountsReceivableMaximumHoldbackPercentage" xlink:label="loc_noa_AccountsReceivableMaximumHoldbackPercentage_DF8A9AFE334388FE6A251D8C14D1B91A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_AccountsReceivableMaximumHoldbackPercentage_DF8A9AFE334388FE6A251D8C14D1B91A" xlink:to="lab_noa_AccountsReceivableMaximumHoldbackPercentage_DF8A9AFE334388FE6A251D8C14D1B91A" xlink:type="arc" />
    <link:label id="lab_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Line of Credit Facility [Table]</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility [Table]</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:to="lab_us-gaap_LineOfCreditFacilityTable_4BDAA5DF2E7EF73EC3C7169678F3A92F" xlink:type="arc" />
    <link:label id="lab_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38_terseLabel_en-US" xlink:label="lab_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Covenant Period [Axis]</link:label>
    <link:label id="lab_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38_label_en-US" xlink:label="lab_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Covenant Period [Axis]</link:label>
    <link:label id="lab_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38_documentation_en-US" xlink:label="lab_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Covenant Period [Axis]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtCovenantPeriodAxis" xlink:label="loc_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:to="lab_noa_DebtCovenantPeriodAxis_1FCCC11BF1057F693124169678F3CC38" xlink:type="arc" />
    <link:label id="lab_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965_terseLabel_en-US" xlink:label="lab_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Covenant Period [Domain]</link:label>
    <link:label id="lab_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965_label_en-US" xlink:label="lab_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Covenant Period [Domain]</link:label>
    <link:label id="lab_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965_documentation_en-US" xlink:label="lab_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">[Domain] for Debt Covenant Period [Axis]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtCovenantPeriodDomain" xlink:label="loc_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:to="lab_noa_DebtCovenantPeriodDomain_F8EC1053A788F50B570D169678F39965" xlink:type="arc" />
    <link:label id="lab_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B_terseLabel_en-US" xlink:label="lab_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Covenant Period, Tranche One</link:label>
    <link:label id="lab_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B_label_en-US" xlink:label="lab_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Covenant Period, Tranche One [Member]</link:label>
    <link:label id="lab_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B_documentation_en-US" xlink:label="lab_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Covenant Period, Tranche One [Member]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtCovenantPeriodTrancheOneMember" xlink:label="loc_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B" xlink:to="lab_noa_DebtCovenantPeriodTrancheOneMember_C98DBEDCE395363745F8169678F4846B" xlink:type="arc" />
    <link:label id="lab_noa_DebtCovenantPeriodTrancheTwoMember_F893F78D9084CC68BE8F169678F4F75A_terseLabel_en-US" xlink:label="lab_noa_DebtCovenantPeriodTrancheTwoMember_F893F78D9084CC68BE8F169678F4F75A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Covenant Period, Tranche Two</link:label>
    <link:label id="lab_noa_DebtCovenantPeriodTrancheTwoMember_F893F78D9084CC68BE8F169678F4F75A_label_en-US" xlink:label="lab_noa_DebtCovenantPeriodTrancheTwoMember_F893F78D9084CC68BE8F169678F4F75A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Covenant Period, Tranche Two [Member]</link:label>
    <link:label id="lab_noa_DebtCovenantPeriodTrancheTwoMember_F893F78D9084CC68BE8F169678F4F75A_documentation_en-US" xlink:label="lab_noa_DebtCovenantPeriodTrancheTwoMember_F893F78D9084CC68BE8F169678F4F75A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Covenant Period, Tranche Two [Member]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtCovenantPeriodTrancheTwoMember" xlink:label="loc_noa_DebtCovenantPeriodTrancheTwoMember_F893F78D9084CC68BE8F169678F4F75A" xlink:type="locator" />
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    <link:label id="lab_noa_NunaCreditFacilityOperatingLoanFacilityMember_B6E76C1EE016F9360369169678F5D5BB_terseLabel_en-US" xlink:label="lab_noa_NunaCreditFacilityOperatingLoanFacilityMember_B6E76C1EE016F9360369169678F5D5BB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nuna Credit Facility - Operating Loan Facility</link:label>
    <link:label id="lab_noa_NunaCreditFacilityOperatingLoanFacilityMember_B6E76C1EE016F9360369169678F5D5BB_label_en-US" xlink:label="lab_noa_NunaCreditFacilityOperatingLoanFacilityMember_B6E76C1EE016F9360369169678F5D5BB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Nuna Credit Facility - Operating Loan Facility [Member]</link:label>
    <link:label id="lab_noa_NunaCreditFacilityOperatingLoanFacilityMember_B6E76C1EE016F9360369169678F5D5BB_documentation_en-US" xlink:label="lab_noa_NunaCreditFacilityOperatingLoanFacilityMember_B6E76C1EE016F9360369169678F5D5BB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Nuna Credit Facility - Operating Loan Facility [Member]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_NunaCreditFacilityOperatingLoanFacilityMember" xlink:label="loc_noa_NunaCreditFacilityOperatingLoanFacilityMember_B6E76C1EE016F9360369169678F5D5BB" xlink:type="locator" />
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    <link:label id="lab_noa_NunaCreditFacilityNonRevolvingReducingLoanFacilityMember_33F1102E6FCD4655B6BE169678F6F447_terseLabel_en-US" xlink:label="lab_noa_NunaCreditFacilityNonRevolvingReducingLoanFacilityMember_33F1102E6FCD4655B6BE169678F6F447" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nuna Credit Facility - Non-Revolving Reducing Loan Facility</link:label>
    <link:label id="lab_noa_NunaCreditFacilityNonRevolvingReducingLoanFacilityMember_33F1102E6FCD4655B6BE169678F6F447_label_en-US" xlink:label="lab_noa_NunaCreditFacilityNonRevolvingReducingLoanFacilityMember_33F1102E6FCD4655B6BE169678F6F447" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Nuna Credit Facility - Non-Revolving Reducing Loan Facility [Member]</link:label>
    <link:label id="lab_noa_NunaCreditFacilityNonRevolvingReducingLoanFacilityMember_33F1102E6FCD4655B6BE169678F6F447_documentation_en-US" xlink:label="lab_noa_NunaCreditFacilityNonRevolvingReducingLoanFacilityMember_33F1102E6FCD4655B6BE169678F6F447" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Nuna Credit Facility - Non-Revolving Reducing Loan Facility [Member]</link:label>
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    <link:label id="lab_noa_NunaCreditFacilityEquipmentFacilityMember_B9339CE727EBF80DD2A0169678F6B909_terseLabel_en-US" xlink:label="lab_noa_NunaCreditFacilityEquipmentFacilityMember_B9339CE727EBF80DD2A0169678F6B909" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nuna Credit Facility - Equipment Facility</link:label>
    <link:label id="lab_noa_NunaCreditFacilityEquipmentFacilityMember_B9339CE727EBF80DD2A0169678F6B909_label_en-US" xlink:label="lab_noa_NunaCreditFacilityEquipmentFacilityMember_B9339CE727EBF80DD2A0169678F6B909" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Nuna Credit Facility - Equipment Facility [Member]</link:label>
    <link:label id="lab_noa_NunaCreditFacilityEquipmentFacilityMember_B9339CE727EBF80DD2A0169678F6B909_documentation_en-US" xlink:label="lab_noa_NunaCreditFacilityEquipmentFacilityMember_B9339CE727EBF80DD2A0169678F6B909" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Nuna Credit Facility - Equipment Facility [Member]</link:label>
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    <link:label id="lab_us-gaap_CreditFacilityAxis_483F1A1595BF8560D6D0169678F66AA8_terseLabel_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis_483F1A1595BF8560D6D0169678F66AA8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Credit Facility [Axis]</link:label>
    <link:label id="lab_us-gaap_CreditFacilityAxis_483F1A1595BF8560D6D0169678F66AA8_label_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis_483F1A1595BF8560D6D0169678F66AA8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Credit Facility [Axis]</link:label>
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    <link:label id="lab_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2_terseLabel_en-US" xlink:label="lab_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Credit Facility [Domain]</link:label>
    <link:label id="lab_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2_label_en-US" xlink:label="lab_us-gaap_CreditFacilityDomain_E85831F649E1D294B089169678F62BE2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Credit Facility [Domain]</link:label>
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    <link:label id="lab_us-gaap_RevolvingCreditFacilityMember_73593D7CC3B1A9AC1B58169678F756B2_terseLabel_en-US" xlink:label="lab_us-gaap_RevolvingCreditFacilityMember_73593D7CC3B1A9AC1B58169678F756B2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revolver</link:label>
    <link:label id="lab_us-gaap_RevolvingCreditFacilityMember_73593D7CC3B1A9AC1B58169678F756B2_label_en-US" xlink:label="lab_us-gaap_RevolvingCreditFacilityMember_73593D7CC3B1A9AC1B58169678F756B2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revolving Credit Facility [Member]</link:label>
    <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" />
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    <link:label id="lab_us-gaap_LetterOfCreditMember_C60D60A242D663D58460169678F7FECD_terseLabel_en-US" xlink:label="lab_us-gaap_LetterOfCreditMember_C60D60A242D663D58460169678F7FECD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Letter of Credit</link:label>
    <link:label id="lab_us-gaap_LetterOfCreditMember_C60D60A242D663D58460169678F7FECD_label_en-US" xlink:label="lab_us-gaap_LetterOfCreditMember_C60D60A242D663D58460169678F7FECD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Letter of Credit [Member]</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LetterOfCreditMember_C60D60A242D663D58460169678F7FECD" xlink:to="lab_us-gaap_LetterOfCreditMember_C60D60A242D663D58460169678F7FECD" xlink:type="arc" />
    <link:label id="lab_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Line of Credit Facility [Line Items]</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility [Line Items]</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:to="lab_us-gaap_LineOfCreditFacilityLineItems_12082E7FBA92123200B5169678F9831C" xlink:type="arc" />
    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_A2F5F263D3FD72C0F972169678F9D6E5_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_A2F5F263D3FD72C0F972169678F9D6E5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum borrowing capacity of credit facility</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_A2F5F263D3FD72C0F972169678F9D6E5_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_A2F5F263D3FD72C0F972169678F9D6E5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_A2F5F263D3FD72C0F972169678F9D6E5" xlink:to="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_A2F5F263D3FD72C0F972169678F9D6E5" xlink:type="arc" />
    <link:label id="lab_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325_terseLabel_en-US" xlink:label="lab_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additional borrowing limit</link:label>
    <link:label id="lab_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325_label_en-US" xlink:label="lab_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Accordion Feature, Increase Limit</link:label>
    <link:label id="lab_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325_documentation_en-US" xlink:label="lab_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Accordion Feature, Increase Limit</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_LineofCreditFacilityAccordionFeatureIncreaseLimit" xlink:label="loc_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325" xlink:to="lab_noa_LineofCreditFacilityAccordionFeatureIncreaseLimit_040CC3335C5858D7D5CD169678FA0325" xlink:type="arc" />
    <link:label id="lab_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B_terseLabel_en-US" xlink:label="lab_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capital lease borrowing limit</link:label>
    <link:label id="lab_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B_label_en-US" xlink:label="lab_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Capital Lease, Maximum Borrowing Capacity</link:label>
    <link:label id="lab_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B_documentation_en-US" xlink:label="lab_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Capital Lease, Maximum Borrowing Capacity</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity" xlink:label="loc_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B" xlink:to="lab_noa_LineofCreditFacilityCapitalLeaseMaximumBorrowingCapacity_738B1BB579D8CB4FA26B169678FAA59B" xlink:type="arc" />
    <link:label id="lab_noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit_8DFDB5C16528CFBD8002169678FAC710_terseLabel_en-US" xlink:label="lab_noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit_8DFDB5C16528CFBD8002169678FAC710" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other outstanding debt limit</link:label>
    <link:label id="lab_noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit_8DFDB5C16528CFBD8002169678FAC710_label_en-US" xlink:label="lab_noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit_8DFDB5C16528CFBD8002169678FAC710" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Allowable Other Debt Outstanding Limit</link:label>
    <link:label id="lab_noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit_8DFDB5C16528CFBD8002169678FAC710_documentation_en-US" xlink:label="lab_noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit_8DFDB5C16528CFBD8002169678FAC710" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Allowable Other Debt Outstanding Limit</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit" xlink:label="loc_noa_LineofCreditFacilityAllowableOtherDebtOutstandingLimit_8DFDB5C16528CFBD8002169678FAC710" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LettersOfCreditOutstandingAmount_00B48D9790F311EF5D97169678FA0841_terseLabel_en-US" xlink:label="lab_us-gaap_LettersOfCreditOutstandingAmount_00B48D9790F311EF5D97169678FA0841" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount outstanding during period</link:label>
    <link:label id="lab_us-gaap_LettersOfCreditOutstandingAmount_00B48D9790F311EF5D97169678FA0841_label_en-US" xlink:label="lab_us-gaap_LettersOfCreditOutstandingAmount_00B48D9790F311EF5D97169678FA0841" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Letters of Credit Outstanding, Amount</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LettersOfCreditOutstandingAmount_00B48D9790F311EF5D97169678FA0841" xlink:to="lab_us-gaap_LettersOfCreditOutstandingAmount_00B48D9790F311EF5D97169678FA0841" xlink:type="arc" />
    <link:label id="lab_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9_terseLabel_en-US" xlink:label="lab_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of financial covenants</link:label>
    <link:label id="lab_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9_label_en-US" xlink:label="lab_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Number of Debt Covenants</link:label>
    <link:label id="lab_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9_documentation_en-US" xlink:label="lab_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Debt Instrument, Number of Debt Covenants</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_DebtInstrumentNumberofDebtCovenants" xlink:label="loc_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9" xlink:to="lab_noa_DebtInstrumentNumberofDebtCovenants_3AE48C62E21D987A95B4169678FB6FB9" xlink:type="arc" />
    <link:label id="lab_noa_RatioOfIndebtednessToNetCapitalRentalRevenue_D1D7024B60652312CB79169678FB4872_terseLabel_en-US" xlink:label="lab_noa_RatioOfIndebtednessToNetCapitalRentalRevenue_D1D7024B60652312CB79169678FB4872" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Senior leverage ratio, rental revenue</link:label>
    <link:label id="lab_noa_RatioOfIndebtednessToNetCapitalRentalRevenue_D1D7024B60652312CB79169678FB4872_label_en-US" xlink:label="lab_noa_RatioOfIndebtednessToNetCapitalRentalRevenue_D1D7024B60652312CB79169678FB4872" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Ratio Of Indebtedness To Net Capital, Rental Revenue</link:label>
    <link:label id="lab_noa_RatioOfIndebtednessToNetCapitalRentalRevenue_D1D7024B60652312CB79169678FB4872_documentation_en-US" xlink:label="lab_noa_RatioOfIndebtednessToNetCapitalRentalRevenue_D1D7024B60652312CB79169678FB4872" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Ratio Of Indebtedness To Net Capital, Rental Revenue</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_RatioOfIndebtednessToNetCapitalRentalRevenue" xlink:label="loc_noa_RatioOfIndebtednessToNetCapitalRentalRevenue_D1D7024B60652312CB79169678FB4872" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_766808FA00E6B572F437169678FBC172_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_766808FA00E6B572F437169678FBC172" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unused borrowing availability under the revolving facility</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_766808FA00E6B572F437169678FBC172_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_766808FA00E6B572F437169678FBC172" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Remaining Borrowing Capacity</link:label>
    <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" />
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    <link:label id="lab_us-gaap_LeaseIncentivePayableCurrentAndNoncurrent_03F0E52D7578C6DB2CA90D1D079206C4_terseLabel_en-US" xlink:label="lab_us-gaap_LeaseIncentivePayableCurrentAndNoncurrent_03F0E52D7578C6DB2CA90D1D079206C4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Balance, end of year</link:label>
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    <link:label id="lab_us-gaap_AssetRetirementObligationRollForwardAnalysisRollForward_CF6A8255EC35A66170450D1D07925F1E_label_en-US" xlink:label="lab_us-gaap_AssetRetirementObligationRollForwardAnalysisRollForward_CF6A8255EC35A66170450D1D07925F1E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetRetirementObligationRollForwardAnalysisRollForward" xlink:label="loc_us-gaap_AssetRetirementObligationRollForwardAnalysisRollForward_CF6A8255EC35A66170450D1D07925F1E" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AssetRetirementObligation_887B3EC053013911DF790D1D07925CA3_periodStartLabel_en-US" xlink:label="lab_us-gaap_AssetRetirementObligation_887B3EC053013911DF790D1D07925CA3" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Balance, beginning of year</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetRetirementObligation" xlink:label="loc_us-gaap_AssetRetirementObligation_887B3EC053013911DF790D1D07925CA3" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AssetRetirementObligation_B24980A58D4E604B5C550D1D079360C9_periodEndLabel_en-US" xlink:label="lab_us-gaap_AssetRetirementObligation_B24980A58D4E604B5C550D1D079360C9" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Balance, end of year</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetRetirementObligation" xlink:label="loc_us-gaap_AssetRetirementObligation_B24980A58D4E604B5C550D1D079360C9" xlink:type="locator" />
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    <link:label id="lab_noa_AssetRetirementObligationEstimatedUndiscountedFutureCashFlowToSettle_DD22CE14851F6A7B6B6D0D1D0794D1FA_terseLabel_en-US" xlink:label="lab_noa_AssetRetirementObligationEstimatedUndiscountedFutureCashFlowToSettle_DD22CE14851F6A7B6B6D0D1D0794D1FA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Estimated undiscounted cash flows required to settle obligation</link:label>
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    <link:loc xlink:href="noa-20181231.xsd#noa_AssetRetirementObligationEstimatedUndiscountedFutureCashFlowToSettle" xlink:label="loc_noa_AssetRetirementObligationEstimatedUndiscountedFutureCashFlowToSettle_DD22CE14851F6A7B6B6D0D1D0794D1FA" xlink:type="locator" />
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    <link:label id="lab_noa_AssetRetirementObligationRiskFreeRateUsedToMeasure_3C39350707C6FEF7CC550D1D07946925_terseLabel_en-US" xlink:label="lab_noa_AssetRetirementObligationRiskFreeRateUsedToMeasure_3C39350707C6FEF7CC550D1D07946925" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Credit adjusted risk-free rate assumed in measuring the asset retirement obligation (percent)</link:label>
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    <link:label id="lab_noa_DeferredGainonSaleLeasebackRollForward_19AF087E82C3A0AD09990D1D07941C70_terseLabel_en-US" xlink:label="lab_noa_DeferredGainonSaleLeasebackRollForward_19AF087E82C3A0AD09990D1D07941C70" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred gain on sale-leaseback [Roll Forward]</link:label>
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    <link:label id="lab_us-gaap_ProfitLoss_F7070531DA93B0CABEB422F29A694F60_verboseLabel_en-US" xlink:label="lab_us-gaap_ProfitLoss_F7070531DA93B0CABEB422F29A694F60" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Net income and comprehensive income</link:label>
    <link:label id="lab_us-gaap_ProfitLoss_F7070531DA93B0CABEB422F29A694F60_label_en-US" xlink:label="lab_us-gaap_ProfitLoss_F7070531DA93B0CABEB422F29A694F60" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss), Including Portion Attributable to Noncontrolling Interest</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProfitLoss_F7070531DA93B0CABEB422F29A694F60" xlink:to="lab_us-gaap_ProfitLoss_F7070531DA93B0CABEB422F29A694F60" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_6DA08F1A982FA079CAE922E53BC74308_verboseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_6DA08F1A982FA079CAE922E53BC74308" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Adjustments to reconcile to net cash from operating activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_6DA08F1A982FA079CAE922E53BC74308_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_6DA08F1A982FA079CAE922E53BC74308" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_6DA08F1A982FA079CAE922E53BC74308" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DepreciationAndAmortization_62FDE94C7635227C2C9B22E53BC8BB25_verboseLabel_en-US" xlink:label="lab_us-gaap_DepreciationAndAmortization_62FDE94C7635227C2C9B22E53BC8BB25" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Depreciation</link:label>
    <link:label id="lab_us-gaap_DepreciationAndAmortization_62FDE94C7635227C2C9B22E53BC8BB25_label_en-US" xlink:label="lab_us-gaap_DepreciationAndAmortization_62FDE94C7635227C2C9B22E53BC8BB25" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Depreciation, Depletion and Amortization, Nonproduction</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="loc_us-gaap_DepreciationAndAmortization_62FDE94C7635227C2C9B22E53BC8BB25" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DepreciationAndAmortization_62FDE94C7635227C2C9B22E53BC8BB25" xlink:to="lab_us-gaap_DepreciationAndAmortization_62FDE94C7635227C2C9B22E53BC8BB25" xlink:type="arc" />
    <link:label id="lab_us-gaap_AmortizationOfIntangibleAssets_1703D69C859CCEE259BB22E53BC8DFA1_terseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfIntangibleAssets_1703D69C859CCEE259BB22E53BC8DFA1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of intangible assets (note 10(b))</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_1703D69C859CCEE259BB22E53BC8DFA1" xlink:type="locator" />
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    <link:label id="lab_noa_ProceedsFromLeaseIncentiveReceivable_AF9E89C3EBB4AC7E6A2022E53BC8170B_terseLabel_en-US" xlink:label="lab_noa_ProceedsFromLeaseIncentiveReceivable_AF9E89C3EBB4AC7E6A2022E53BC8170B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease inducement received (note 17(b))</link:label>
    <link:label id="lab_noa_ProceedsFromLeaseIncentiveReceivable_AF9E89C3EBB4AC7E6A2022E53BC8170B_label_en-US" xlink:label="lab_noa_ProceedsFromLeaseIncentiveReceivable_AF9E89C3EBB4AC7E6A2022E53BC8170B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds From Lease Incentive Receivable</link:label>
    <link:label id="lab_noa_ProceedsFromLeaseIncentiveReceivable_AF9E89C3EBB4AC7E6A2022E53BC8170B_documentation_en-US" xlink:label="lab_noa_ProceedsFromLeaseIncentiveReceivable_AF9E89C3EBB4AC7E6A2022E53BC8170B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Proceeds From Lease Incentive Receivable</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_ProceedsFromLeaseIncentiveReceivable" xlink:label="loc_noa_ProceedsFromLeaseIncentiveReceivable_AF9E89C3EBB4AC7E6A2022E53BC8170B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_ProceedsFromLeaseIncentiveReceivable_AF9E89C3EBB4AC7E6A2022E53BC8170B" xlink:to="lab_noa_ProceedsFromLeaseIncentiveReceivable_AF9E89C3EBB4AC7E6A2022E53BC8170B" xlink:type="arc" />
    <link:label id="lab_us-gaap_AmortizationOfFinancingCosts_8BF234913C3C79E929BC22E53BC828D6_verboseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfFinancingCosts_8BF234913C3C79E929BC22E53BC828D6" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Amortization of deferred financing costs (notes 10(c), 14(e) and 21)</link:label>
    <link:label id="lab_us-gaap_AmortizationOfFinancingCosts_8BF234913C3C79E929BC22E53BC828D6_label_en-US" xlink:label="lab_us-gaap_AmortizationOfFinancingCosts_8BF234913C3C79E929BC22E53BC828D6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Debt Issuance Costs</link:label>
    <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_8BF234913C3C79E929BC22E53BC828D6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AmortizationOfFinancingCosts_8BF234913C3C79E929BC22E53BC828D6" xlink:to="lab_us-gaap_AmortizationOfFinancingCosts_8BF234913C3C79E929BC22E53BC828D6" xlink:type="arc" />
    <link:label id="lab_noa_GainLossOnSubleaseIncome_D245951523E3E590E7D322E53BC8F27E_negatedLabel_en-US" xlink:label="lab_noa_GainLossOnSubleaseIncome_D245951523E3E590E7D322E53BC8F27E" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Loss on sublease (note 17(e))</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_GainLossOnSubleaseIncome" xlink:label="loc_noa_GainLossOnSubleaseIncome_D245951523E3E590E7D322E53BC8F27E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_GainLossOnSubleaseIncome_D245951523E3E590E7D322E53BC8F27E" xlink:to="lab_noa_GainLossOnSubleaseIncome_D245951523E3E590E7D322E53BC8F27E" xlink:type="arc" />
    <link:label id="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_B6EEE64B39D5B6CAF73522E53BC98572_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_B6EEE64B39D5B6CAF73522E53BC98572" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Loss on disposal of property, plant and equipment</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_B6EEE64B39D5B6CAF73522E53BC98572_label_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_B6EEE64B39D5B6CAF73522E53BC98572" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Disposition of Property Plant Equipment</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_B6EEE64B39D5B6CAF73522E53BC98572" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_B6EEE64B39D5B6CAF73522E53BC98572" xlink:to="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_B6EEE64B39D5B6CAF73522E53BC98572" xlink:type="arc" />
    <link:label id="lab_us-gaap_GainLossOnDispositionOfAssets_A2D1C7552E6458847FF122E53BC943EA_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnDispositionOfAssets_A2D1C7552E6458847FF122E53BC943EA" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Gain on disposal of assets held for sale (note 8)</link:label>
    <link:label id="lab_us-gaap_GainLossOnDispositionOfAssets_A2D1C7552E6458847FF122E53BC943EA_label_en-US" xlink:label="lab_us-gaap_GainLossOnDispositionOfAssets_A2D1C7552E6458847FF122E53BC943EA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets_A2D1C7552E6458847FF122E53BC943EA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainLossOnDispositionOfAssets_A2D1C7552E6458847FF122E53BC943EA" xlink:to="lab_us-gaap_GainLossOnDispositionOfAssets_A2D1C7552E6458847FF122E53BC943EA" xlink:type="arc" />
    <link:label id="lab_us-gaap_ShareBasedCompensation_1A132356F75E344D54BC22E53BC9AE54_verboseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation_1A132356F75E344D54BC22E53BC9AE54" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Stock-based compensation expense (note 22(a))</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensation_1A132356F75E344D54BC22E53BC9AE54_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation_1A132356F75E344D54BC22E53BC9AE54" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_1A132356F75E344D54BC22E53BC9AE54" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensation_1A132356F75E344D54BC22E53BC9AE54" xlink:to="lab_us-gaap_ShareBasedCompensation_1A132356F75E344D54BC22E53BC9AE54" xlink:type="arc" />
    <link:label id="lab_noa_CashSettlementOfRestrictedShareUnitPlan_5A70DCD1CEF2EC7284A122E53BC9B2BB_negatedLabel_en-US" xlink:label="lab_noa_CashSettlementOfRestrictedShareUnitPlan_5A70DCD1CEF2EC7284A122E53BC9B2BB" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Cash settlement of stock-based compensation (note 22(e))</link:label>
    <link:label id="lab_noa_CashSettlementOfRestrictedShareUnitPlan_5A70DCD1CEF2EC7284A122E53BC9B2BB_label_en-US" xlink:label="lab_noa_CashSettlementOfRestrictedShareUnitPlan_5A70DCD1CEF2EC7284A122E53BC9B2BB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Settlement Of Restricted Share Unit Plan</link:label>
    <link:label id="lab_noa_CashSettlementOfRestrictedShareUnitPlan_5A70DCD1CEF2EC7284A122E53BC9B2BB_documentation_en-US" xlink:label="lab_noa_CashSettlementOfRestrictedShareUnitPlan_5A70DCD1CEF2EC7284A122E53BC9B2BB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash Settlement Of Restricted Share Unit Plan</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_CashSettlementOfRestrictedShareUnitPlan" xlink:label="loc_noa_CashSettlementOfRestrictedShareUnitPlan_5A70DCD1CEF2EC7284A122E53BC9B2BB" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_95D4D2D227B1C395B6FC22E53BC9D02A_negatedLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments_95D4D2D227B1C395B6FC22E53BC9D02A" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Equity earnings in affiliates and joint ventures (note 13(a))</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_95D4D2D227B1C395B6FC22E53BC9D02A_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments_95D4D2D227B1C395B6FC22E53BC9D02A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Equity Method Investments</link:label>
    <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_95D4D2D227B1C395B6FC22E53BC9D02A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromEquityMethodInvestments_95D4D2D227B1C395B6FC22E53BC9D02A" xlink:to="lab_us-gaap_IncomeLossFromEquityMethodInvestments_95D4D2D227B1C395B6FC22E53BC9D02A" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_A84C75DA1772A29D375B22E53BC9311F_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense_A84C75DA1772A29D375B22E53BC9311F" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Other adjustments to cash from operating activities</link:label>
    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_A84C75DA1772A29D375B22E53BC9311F_label_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense_A84C75DA1772A29D375B22E53BC9311F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Noncash Income (Expense)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_A84C75DA1772A29D375B22E53BC9311F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNoncashIncomeExpense_A84C75DA1772A29D375B22E53BC9311F" xlink:to="lab_us-gaap_OtherNoncashIncomeExpense_A84C75DA1772A29D375B22E53BC9311F" xlink:type="arc" />
    <link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_CBCA0E1B9B808BF7D7DB22E53BCA26C0_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_CBCA0E1B9B808BF7D7DB22E53BCA26C0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred income tax expense (note 11)</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_CBCA0E1B9B808BF7D7DB22E53BCA26C0_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_CBCA0E1B9B808BF7D7DB22E53BCA26C0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Income Tax Expense (Benefit)</link:label>
    <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_CBCA0E1B9B808BF7D7DB22E53BCA26C0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_CBCA0E1B9B808BF7D7DB22E53BCA26C0" xlink:to="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_CBCA0E1B9B808BF7D7DB22E53BCA26C0" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapital_8983AE3553D7FB9021C022E53BCA120B_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapital_8983AE3553D7FB9021C022E53BCA120B" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Net changes in non-cash working capital (note 23(b))</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapital_8983AE3553D7FB9021C022E53BCA120B_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapital_8983AE3553D7FB9021C022E53BCA120B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Operating Capital</link:label>
    <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_8983AE3553D7FB9021C022E53BCA120B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapital_8983AE3553D7FB9021C022E53BCA120B" xlink:to="lab_us-gaap_IncreaseDecreaseInOperatingCapital_8983AE3553D7FB9021C022E53BCA120B" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_2C968DB030AF8F9811D822E53BCAB209_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_2C968DB030AF8F9811D822E53BCAB209" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total operating activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_2C968DB030AF8F9811D822E53BCAB209_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_2C968DB030AF8F9811D822E53BCAB209" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities</link:label>
    <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_2C968DB030AF8F9811D822E53BCAB209" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_2C968DB030AF8F9811D822E53BCAB209" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_2C968DB030AF8F9811D822E53BCAB209" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_A03A754A28A04C12316D22E53BCAD8E8_verboseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_A03A754A28A04C12316D22E53BCAD8E8" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Investing activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_A03A754A28A04C12316D22E53BCAD8E8_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_A03A754A28A04C12316D22E53BCAD8E8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Investing Activities [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_A03A754A28A04C12316D22E53BCAD8E8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_A03A754A28A04C12316D22E53BCAD8E8" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_A03A754A28A04C12316D22E53BCAD8E8" xlink:type="arc" />
    <link:label id="lab_noa_PaymentsforAssetAcquisitions_CD009955069EE29F258022E53BCA8B41_negatedTerseLabel_en-US" xlink:label="lab_noa_PaymentsforAssetAcquisitions_CD009955069EE29F258022E53BCA8B41" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Acquisition of heavy construction fleet and related assets (note 5(b))</link:label>
    <link:label id="lab_noa_PaymentsforAssetAcquisitions_CD009955069EE29F258022E53BCA8B41_label_en-US" xlink:label="lab_noa_PaymentsforAssetAcquisitions_CD009955069EE29F258022E53BCA8B41" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for Asset Acquisitions</link:label>
    <link:label id="lab_noa_PaymentsforAssetAcquisitions_CD009955069EE29F258022E53BCA8B41_documentation_en-US" xlink:label="lab_noa_PaymentsforAssetAcquisitions_CD009955069EE29F258022E53BCA8B41" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Payments for Asset Acquisitions</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_PaymentsforAssetAcquisitions" xlink:label="loc_noa_PaymentsforAssetAcquisitions_CD009955069EE29F258022E53BCA8B41" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_PaymentsforAssetAcquisitions_CD009955069EE29F258022E53BCA8B41" xlink:to="lab_noa_PaymentsforAssetAcquisitions_CD009955069EE29F258022E53BCA8B41" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquireInterestInJointVenture_6D35A628356BE0E7558422E53BCB0235_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireInterestInJointVenture_6D35A628356BE0E7558422E53BCB0235" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Purchase of property, plant and equipment</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireInterestInJointVenture_6D35A628356BE0E7558422E53BCB0235_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireInterestInJointVenture_6D35A628356BE0E7558422E53BCB0235" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Interest in Joint Venture</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:label="loc_us-gaap_PaymentsToAcquireInterestInJointVenture_6D35A628356BE0E7558422E53BCB0235" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireInterestInJointVenture_6D35A628356BE0E7558422E53BCB0235" xlink:to="lab_us-gaap_PaymentsToAcquireInterestInJointVenture_6D35A628356BE0E7558422E53BCB0235" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_8590A31D0861B0E3B23E22E53BCBD299_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_8590A31D0861B0E3B23E22E53BCBD299" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Investment in DNSS Partnership (note 13(b))</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_8590A31D0861B0E3B23E22E53BCBD299_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_8590A31D0861B0E3B23E22E53BCBD299" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Limited Partnership Interests</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireLimitedPartnershipInterests" xlink:label="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_8590A31D0861B0E3B23E22E53BCBD299" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_8590A31D0861B0E3B23E22E53BCBD299" xlink:to="lab_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_8590A31D0861B0E3B23E22E53BCBD299" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_DC9B98D8950E6047138E22E53BCBFF93_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_DC9B98D8950E6047138E22E53BCBFF93" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Purchase of property, plant and equipment</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_DC9B98D8950E6047138E22E53BCBFF93_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_DC9B98D8950E6047138E22E53BCBFF93" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Property, Plant, and Equipment</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_DC9B98D8950E6047138E22E53BCBFF93" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_DC9B98D8950E6047138E22E53BCBFF93" xlink:to="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_DC9B98D8950E6047138E22E53BCBFF93" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquireIntangibleAssets_788563E5AB901EE8459F22E53BCBE539_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireIntangibleAssets_788563E5AB901EE8459F22E53BCBE539" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Additions to intangible assets (note 10(b))</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireIntangibleAssets_788563E5AB901EE8459F22E53BCBE539_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireIntangibleAssets_788563E5AB901EE8459F22E53BCBE539" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Intangible Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireIntangibleAssets" xlink:label="loc_us-gaap_PaymentsToAcquireIntangibleAssets_788563E5AB901EE8459F22E53BCBE539" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireIntangibleAssets_788563E5AB901EE8459F22E53BCBE539" xlink:to="lab_us-gaap_PaymentsToAcquireIntangibleAssets_788563E5AB901EE8459F22E53BCBE539" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_3F96B782D58EECF69B6F22E53BCB609C_verboseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_3F96B782D58EECF69B6F22E53BCB609C" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Proceeds on disposal of property, plant and equipment</link:label>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_3F96B782D58EECF69B6F22E53BCB609C_label_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_3F96B782D58EECF69B6F22E53BCB609C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Sale of Property, Plant, and Equipment</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_3F96B782D58EECF69B6F22E53BCB609C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_3F96B782D58EECF69B6F22E53BCB609C" xlink:to="lab_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_3F96B782D58EECF69B6F22E53BCB609C" xlink:type="arc" />
    <link:label id="lab_noa_ProceedsFromDisposalOfPropertyHeldForSale_2708FE18C91977675DBC22E53BCB5848_verboseLabel_en-US" xlink:label="lab_noa_ProceedsFromDisposalOfPropertyHeldForSale_2708FE18C91977675DBC22E53BCB5848" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Proceeds on disposal of assets held for sale</link:label>
    <link:label id="lab_noa_ProceedsFromDisposalOfPropertyHeldForSale_2708FE18C91977675DBC22E53BCB5848_label_en-US" xlink:label="lab_noa_ProceedsFromDisposalOfPropertyHeldForSale_2708FE18C91977675DBC22E53BCB5848" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Disposal of Property Held for Sale</link:label>
    <link:label id="lab_noa_ProceedsFromDisposalOfPropertyHeldForSale_2708FE18C91977675DBC22E53BCB5848_documentation_en-US" xlink:label="lab_noa_ProceedsFromDisposalOfPropertyHeldForSale_2708FE18C91977675DBC22E53BCB5848" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Proceeds on disposal of assets held for sale</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_ProceedsFromDisposalOfPropertyHeldForSale" xlink:label="loc_noa_ProceedsFromDisposalOfPropertyHeldForSale_2708FE18C91977675DBC22E53BCB5848" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_ProceedsFromDisposalOfPropertyHeldForSale_2708FE18C91977675DBC22E53BCB5848" xlink:to="lab_noa_ProceedsFromDisposalOfPropertyHeldForSale_2708FE18C91977675DBC22E53BCB5848" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquireNotesReceivable_B0E50340E096CC2835E822E53BCCC12D_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireNotesReceivable_B0E50340E096CC2835E822E53BCCC12D" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Additions to other long term receivable (note 10)</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireNotesReceivable_B0E50340E096CC2835E822E53BCCC12D_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireNotesReceivable_B0E50340E096CC2835E822E53BCCC12D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Notes Receivable</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireNotesReceivable" xlink:label="loc_us-gaap_PaymentsToAcquireNotesReceivable_B0E50340E096CC2835E822E53BCCC12D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireNotesReceivable_B0E50340E096CC2835E822E53BCCC12D" xlink:to="lab_us-gaap_PaymentsToAcquireNotesReceivable_B0E50340E096CC2835E822E53BCCC12D" xlink:type="arc" />
    <link:label id="lab_noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate_2B5570A9D690A25CD38022E53BCC917F_terseLabel_en-US" xlink:label="lab_noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate_2B5570A9D690A25CD38022E53BCC917F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net repayment of (advances to) DNSS Partnership loan (notes 10(a) and 13(b))</link:label>
    <link:label id="lab_noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate_2B5570A9D690A25CD38022E53BCC917F_label_en-US" xlink:label="lab_noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate_2B5570A9D690A25CD38022E53BCC917F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds From Collection Of (Payments For) Advance To Affiliate</link:label>
    <link:label id="lab_noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate_2B5570A9D690A25CD38022E53BCC917F_documentation_en-US" xlink:label="lab_noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate_2B5570A9D690A25CD38022E53BCC917F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Proceeds From Collection Of (Payments For) Advance To Affiliate</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate" xlink:label="loc_noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate_2B5570A9D690A25CD38022E53BCC917F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate_2B5570A9D690A25CD38022E53BCC917F" xlink:to="lab_noa_ProceedsFromCollectionOfPaymentsForAdvanceToAffiliate_2B5570A9D690A25CD38022E53BCC917F" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_D97967B555ACB12CCD6F22E53BCC23BE_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_D97967B555ACB12CCD6F22E53BCC23BE" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total investing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_D97967B555ACB12CCD6F22E53BCC23BE_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_D97967B555ACB12CCD6F22E53BCC23BE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Investing Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_D97967B555ACB12CCD6F22E53BCC23BE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_D97967B555ACB12CCD6F22E53BCC23BE" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_D97967B555ACB12CCD6F22E53BCC23BE" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_2C3C2150AC584874257D22E53BCC84B1_verboseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_2C3C2150AC584874257D22E53BCC84B1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Financing activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_2C3C2150AC584874257D22E53BCC84B1_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_2C3C2150AC584874257D22E53BCC84B1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities [Abstract]</link:label>
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    <link:label id="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_C345C747B0B19C4E013022E53BCCB107_negatedLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_C345C747B0B19C4E013022E53BCCB107" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Repayment of credit facilities</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_C345C747B0B19C4E013022E53BCCB107_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermLinesOfCredit_C345C747B0B19C4E013022E53BCCB107" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Long-term Lines of Credit</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit_C345C747B0B19C4E013022E53BCCB107" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_F3906443F149B1E4B6E622E53BCC4ED8_verboseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_F3906443F149B1E4B6E622E53BCC4ED8" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Increase in credit facilities</link:label>
    <link:label id="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_F3906443F149B1E4B6E622E53BCC4ED8_label_en-US" xlink:label="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_F3906443F149B1E4B6E622E53BCC4ED8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Long-term Lines of Credit</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLongTermLinesOfCredit_F3906443F149B1E4B6E622E53BCC4ED8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromLongTermLinesOfCredit_F3906443F149B1E4B6E622E53BCC4ED8" xlink:to="lab_us-gaap_ProceedsFromLongTermLinesOfCredit_F3906443F149B1E4B6E622E53BCC4ED8" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProceedsFromConvertibleDebt_FDF6D1C74E30D3AED2ED22E53BCDBD3C_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromConvertibleDebt_FDF6D1C74E30D3AED2ED22E53BCDBD3C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Issuance of Convertible Debentures (note 14(c))</link:label>
    <link:label id="lab_us-gaap_ProceedsFromConvertibleDebt_FDF6D1C74E30D3AED2ED22E53BCDBD3C_label_en-US" xlink:label="lab_us-gaap_ProceedsFromConvertibleDebt_FDF6D1C74E30D3AED2ED22E53BCDBD3C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Convertible Debt</link:label>
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    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfFirstMortgageBond_B86E262EABA338C4122222E53BCD93EB_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfFirstMortgageBond_B86E262EABA338C4122222E53BCD93EB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage proceeds (note 14(d))</link:label>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfFirstMortgageBond_B86E262EABA338C4122222E53BCD93EB_label_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfFirstMortgageBond_B86E262EABA338C4122222E53BCD93EB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Issuance of First Mortgage Bond</link:label>
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    <link:label id="lab_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_64CF9470F4ED035EBEC522E53BCDC872_negatedLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_64CF9470F4ED035EBEC522E53BCDC872" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Repayment of capital lease obligations</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_64CF9470F4ED035EBEC522E53BCDC872_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermCapitalLeaseObligations_64CF9470F4ED035EBEC522E53BCDC872" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Long-term Capital Lease Obligations</link:label>
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    <link:label id="lab_us-gaap_RepaymentsOfNotesPayable_82460C49FF2125F78EC622E53BCDE1AF_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfNotesPayable_82460C49FF2125F78EC622E53BCDE1AF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Notes Payable</link:label>
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    <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_F6A60CEB13C31DB9694C22E53BCD11DB" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PaymentsOfDividends_AB1CDBD705CEB18E939622E53BCE82B2_label_en-US" xlink:label="lab_us-gaap_PaymentsOfDividends_AB1CDBD705CEB18E939622E53BCE82B2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments of Dividends</link:label>
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    <link:label id="lab_us-gaap_PaymentsForRepurchaseOfCommonStock_9C6F1840C6CC50648E5D22E53BCEA983_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsForRepurchaseOfCommonStock_9C6F1840C6CC50648E5D22E53BCEA983" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Share purchase programs (note 18(c))</link:label>
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    <link:label id="lab_noa_PaymentsforRepurchaseofCommonStockUnitSettlement_B916B7D48AE6059CBA4622E53BCE1526_label_en-US" xlink:label="lab_noa_PaymentsforRepurchaseofCommonStockUnitSettlement_B916B7D48AE6059CBA4622E53BCE1526" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for Repurchase of Common Stock, Unit Settlement</link:label>
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_9AFB19BA5D6E91877D9F22E53BCE2E46_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_9AFB19BA5D6E91877D9F22E53BCE2E46" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total financing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_9AFB19BA5D6E91877D9F22E53BCE2E46_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_9AFB19BA5D6E91877D9F22E53BCE2E46" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities</link:label>
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    <link:label id="lab_us-gaap_FurnitureAndFixturesMember_7C735AF394B32540478FAAADBE92AD24_terseLabel_en-US" xlink:label="lab_us-gaap_FurnitureAndFixturesMember_7C735AF394B32540478FAAADBE92AD24" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Furnishings, fixtures and facilities</link:label>
    <link:label id="lab_us-gaap_FurnitureAndFixturesMember_7C735AF394B32540478FAAADBE92AD24_label_en-US" xlink:label="lab_us-gaap_FurnitureAndFixturesMember_7C735AF394B32540478FAAADBE92AD24" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Furniture and Fixtures [Member]</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FurnitureAndFixturesMember_7C735AF394B32540478FAAADBE92AD24" xlink:to="lab_us-gaap_FurnitureAndFixturesMember_7C735AF394B32540478FAAADBE92AD24" xlink:type="arc" />
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_5CFC99AE4AEE2858892FAA17D6D7BF61_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_5CFC99AE4AEE2858892FAA17D6D7BF61" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment, useful life</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_5CFC99AE4AEE2858892FAA17D6D7BF61_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_5CFC99AE4AEE2858892FAA17D6D7BF61" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Useful Life</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_5CFC99AE4AEE2858892FAA17D6D7BF61" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_5CFC99AE4AEE2858892FAA17D6D7BF61" xlink:type="arc" />
    <link:label id="lab_noa_CashPaidDuringYearAbstract_C42538584B1EBEEE64D39644039B9776_terseLabel_en-US" xlink:label="lab_noa_CashPaidDuringYearAbstract_C42538584B1EBEEE64D39644039B9776" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash paid during the year for:</link:label>
    <link:label id="lab_noa_CashPaidDuringYearAbstract_C42538584B1EBEEE64D39644039B9776_label_en-US" xlink:label="lab_noa_CashPaidDuringYearAbstract_C42538584B1EBEEE64D39644039B9776" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Paid During the Year [Abstract]</link:label>
    <link:label id="lab_noa_CashPaidDuringYearAbstract_C42538584B1EBEEE64D39644039B9776_documentation_en-US" xlink:label="lab_noa_CashPaidDuringYearAbstract_C42538584B1EBEEE64D39644039B9776" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash Paid During the Year [Abstract]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_CashPaidDuringYearAbstract" xlink:label="loc_noa_CashPaidDuringYearAbstract_C42538584B1EBEEE64D39644039B9776" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_CashPaidDuringYearAbstract_C42538584B1EBEEE64D39644039B9776" xlink:to="lab_noa_CashPaidDuringYearAbstract_C42538584B1EBEEE64D39644039B9776" xlink:type="arc" />
    <link:label id="lab_us-gaap_InterestPaidNet_B733CD545AECF819EBC69669457F81EC_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPaidNet_B733CD545AECF819EBC69669457F81EC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest</link:label>
    <link:label id="lab_us-gaap_InterestPaidNet_B733CD545AECF819EBC69669457F81EC_label_en-US" xlink:label="lab_us-gaap_InterestPaidNet_B733CD545AECF819EBC69669457F81EC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Paid, Excluding Capitalized Interest, Operating Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestPaidNet" xlink:label="loc_us-gaap_InterestPaidNet_B733CD545AECF819EBC69669457F81EC" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestPaidNet_B733CD545AECF819EBC69669457F81EC" xlink:to="lab_us-gaap_InterestPaidNet_B733CD545AECF819EBC69669457F81EC" xlink:type="arc" />
    <link:label id="lab_noa_CashReceivedDuringYearAbstract_93F2D7C0613F93CD556A9644039B5DDA_terseLabel_en-US" xlink:label="lab_noa_CashReceivedDuringYearAbstract_93F2D7C0613F93CD556A9644039B5DDA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash received during the year for:</link:label>
    <link:label id="lab_noa_CashReceivedDuringYearAbstract_93F2D7C0613F93CD556A9644039B5DDA_label_en-US" xlink:label="lab_noa_CashReceivedDuringYearAbstract_93F2D7C0613F93CD556A9644039B5DDA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Received During the Year [Abstract]</link:label>
    <link:label id="lab_noa_CashReceivedDuringYearAbstract_93F2D7C0613F93CD556A9644039B5DDA_documentation_en-US" xlink:label="lab_noa_CashReceivedDuringYearAbstract_93F2D7C0613F93CD556A9644039B5DDA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash Received During the Year [Abstract]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_CashReceivedDuringYearAbstract" xlink:label="loc_noa_CashReceivedDuringYearAbstract_93F2D7C0613F93CD556A9644039B5DDA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_CashReceivedDuringYearAbstract_93F2D7C0613F93CD556A9644039B5DDA" xlink:to="lab_noa_CashReceivedDuringYearAbstract_93F2D7C0613F93CD556A9644039B5DDA" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProceedsFromInterestReceived_BFB21433F90431D841949644039C1BAE_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromInterestReceived_BFB21433F90431D841949644039C1BAE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest</link:label>
    <link:label id="lab_us-gaap_ProceedsFromInterestReceived_BFB21433F90431D841949644039C1BAE_label_en-US" xlink:label="lab_us-gaap_ProceedsFromInterestReceived_BFB21433F90431D841949644039C1BAE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Interest Received</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromInterestReceived" xlink:label="loc_us-gaap_ProceedsFromInterestReceived_BFB21433F90431D841949644039C1BAE" xlink:type="locator" />
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    <link:label id="lab_us-gaap_InterestPayableCurrent_2A76B1B9DF2F89C751380D7ACC4A0E8A_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPayableCurrent_2A76B1B9DF2F89C751380D7ACC4A0E8A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued interest payable</link:label>
    <link:label id="lab_us-gaap_InterestPayableCurrent_2A76B1B9DF2F89C751380D7ACC4A0E8A_label_en-US" xlink:label="lab_us-gaap_InterestPayableCurrent_2A76B1B9DF2F89C751380D7ACC4A0E8A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Payable, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestPayableCurrent" xlink:label="loc_us-gaap_InterestPayableCurrent_2A76B1B9DF2F89C751380D7ACC4A0E8A" xlink:type="locator" />
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    <link:label id="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_8321B004C6097074F7170D7ACC4A2DD6_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_8321B004C6097074F7170D7ACC4A2DD6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Payroll liabilities</link:label>
    <link:label id="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_8321B004C6097074F7170D7ACC4A2DD6_label_en-US" xlink:label="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_8321B004C6097074F7170D7ACC4A2DD6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Employee-related Liabilities, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_8321B004C6097074F7170D7ACC4A2DD6" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AccruedRentCurrent_596DB8276EF9A4A9AAE40D7ACC4A0602_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedRentCurrent_596DB8276EF9A4A9AAE40D7ACC4A0602" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities related to equipment leases</link:label>
    <link:label id="lab_us-gaap_AccruedRentCurrent_596DB8276EF9A4A9AAE40D7ACC4A0602_label_en-US" xlink:label="lab_us-gaap_AccruedRentCurrent_596DB8276EF9A4A9AAE40D7ACC4A0602" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued Rent, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccruedRentCurrent" xlink:label="loc_us-gaap_AccruedRentCurrent_596DB8276EF9A4A9AAE40D7ACC4A0602" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DividendsPayableCurrent_07E28D478CA9F88869950D7ACC4A6A10_terseLabel_en-US" xlink:label="lab_us-gaap_DividendsPayableCurrent_07E28D478CA9F88869950D7ACC4A6A10" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dividends payable (note 18(d))</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DividendsPayableCurrent" xlink:label="loc_us-gaap_DividendsPayableCurrent_07E28D478CA9F88869950D7ACC4A6A10" xlink:type="locator" />
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    <link:label id="lab_us-gaap_TaxesPayableCurrent_E6A21416F4211F3202450D7ACC4B5982_terseLabel_en-US" xlink:label="lab_us-gaap_TaxesPayableCurrent_E6A21416F4211F3202450D7ACC4B5982" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income and other taxes payable</link:label>
    <link:label id="lab_us-gaap_TaxesPayableCurrent_E6A21416F4211F3202450D7ACC4B5982_label_en-US" xlink:label="lab_us-gaap_TaxesPayableCurrent_E6A21416F4211F3202450D7ACC4B5982" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Taxes Payable, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TaxesPayableCurrent" xlink:label="loc_us-gaap_TaxesPayableCurrent_E6A21416F4211F3202450D7ACC4B5982" xlink:type="locator" />
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    <link:label id="lab_noa_TireDisposalLiabilitiesCurrent_BA47D675E91443FC95270D7ACC4B77E0_terseLabel_en-US" xlink:label="lab_noa_TireDisposalLiabilitiesCurrent_BA47D675E91443FC95270D7ACC4B77E0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities related to tire disposal</link:label>
    <link:label id="lab_noa_TireDisposalLiabilitiesCurrent_BA47D675E91443FC95270D7ACC4B77E0_label_en-US" xlink:label="lab_noa_TireDisposalLiabilitiesCurrent_BA47D675E91443FC95270D7ACC4B77E0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tire Disposal Liabilities, Current</link:label>
    <link:label id="lab_noa_TireDisposalLiabilitiesCurrent_BA47D675E91443FC95270D7ACC4B77E0_documentation_en-US" xlink:label="lab_noa_TireDisposalLiabilitiesCurrent_BA47D675E91443FC95270D7ACC4B77E0" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tire Disposal Liabilities, Current</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_TireDisposalLiabilitiesCurrent" xlink:label="loc_noa_TireDisposalLiabilitiesCurrent_BA47D675E91443FC95270D7ACC4B77E0" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrent_3D9D6336092BED6E0A730D7ACC4BBC3A_totalLabel_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent_3D9D6336092BED6E0A730D7ACC4BBC3A" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Accrued liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_3D9D6336092BED6E0A730D7ACC4BBC3A" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ScheduleOfCommonStockOutstandingRollForwardTableTextBlock_F1D7ED8279051CF344A9E76F29458FEF_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCommonStockOutstandingRollForwardTableTextBlock_F1D7ED8279051CF344A9E76F29458FEF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of common shares</link:label>
    <link:label id="lab_us-gaap_ScheduleOfCommonStockOutstandingRollForwardTableTextBlock_F1D7ED8279051CF344A9E76F29458FEF_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCommonStockOutstandingRollForwardTableTextBlock_F1D7ED8279051CF344A9E76F29458FEF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Common Stock Outstanding Roll Forward [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_AF9D0369BB2CA71C1AD3E76F29465EEA_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_AF9D0369BB2CA71C1AD3E76F29465EEA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of net income per share</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_AF9D0369BB2CA71C1AD3E76F29465EEA_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_AF9D0369BB2CA71C1AD3E76F29465EEA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_F81B16CD7208ECA737360C95ABF20DDC_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_F81B16CD7208ECA737360C95ABF20DDC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_F81B16CD7208ECA737360C95ABF20DDC_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_F81B16CD7208ECA737360C95ABF20DDC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TradeAndOtherAccountsReceivablePolicy" xlink:label="loc_us-gaap_TradeAndOtherAccountsReceivablePolicy_1BFDA9FC8FDA8AB5009C0C95ABF2EC85" xlink:type="locator" />
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    <link:loc xlink:href="noa-20181231.xsd#noa_TradeAndOtherAccountsReceivableAllowanceForDoubtfulAccountsPolicyTableTextBlock" xlink:label="loc_noa_TradeAndOtherAccountsReceivableAllowanceForDoubtfulAccountsPolicyTableTextBlock_687386675E94F1767C100C95ABF2BC5C" xlink:type="locator" />
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    <link:label id="lab_us-gaap_InventoryPolicyTextBlock_1A5D57CFD18792ADD3F60C95ABF370DA_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryPolicyTextBlock_1A5D57CFD18792ADD3F60C95ABF370DA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Inventories</link:label>
    <link:label id="lab_us-gaap_InventoryPolicyTextBlock_1A5D57CFD18792ADD3F60C95ABF370DA_label_en-US" xlink:label="lab_us-gaap_InventoryPolicyTextBlock_1A5D57CFD18792ADD3F60C95ABF370DA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Inventory, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InventoryPolicyTextBlock" xlink:label="loc_us-gaap_InventoryPolicyTextBlock_1A5D57CFD18792ADD3F60C95ABF370DA" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_17D68ADDFA18A49B3A830C95ABF38254_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_17D68ADDFA18A49B3A830C95ABF38254" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_17D68ADDFA18A49B3A830C95ABF38254_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_17D68ADDFA18A49B3A830C95ABF38254" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_17D68ADDFA18A49B3A830C95ABF38254" xlink:type="locator" />
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    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_D710E580433C1164F5FE0C95ABF341DC_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_D710E580433C1164F5FE0C95ABF341DC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intangible assets</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_D710E580433C1164F5FE0C95ABF341DC" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_D710E580433C1164F5FE0C95ABF341DC" xlink:to="lab_us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_D710E580433C1164F5FE0C95ABF341DC" xlink:type="arc" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:label="loc_us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock_130C2415CA5B6803DB9D0C95ABF372D3" xlink:type="locator" />
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    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_B72BF5F9D69059BE463922E1E6AE0A3D_periodStartLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_B72BF5F9D69059BE463922E1E6AE0A3D" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Beginning balance</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_B72BF5F9D69059BE463922E1E6AE0A3D" xlink:to="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_B72BF5F9D69059BE463922E1E6AE0A3D" xlink:type="arc" />
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_B7EF85AEC6FA44A9664A22E1E6AE4332_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_B7EF85AEC6FA44A9664A22E1E6AE4332" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exercised options (note 22(b))</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_B7EF85AEC6FA44A9664A22E1E6AE4332_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_B7EF85AEC6FA44A9664A22E1E6AE4332" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Value, Stock Options Exercised</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_B7EF85AEC6FA44A9664A22E1E6AE4332" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_B7EF85AEC6FA44A9664A22E1E6AE4332" xlink:type="arc" />
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5C54397FE57219429B8F22E1E6AFD30F_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5C54397FE57219429B8F22E1E6AFD30F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock-based compensation (note 22)</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5C54397FE57219429B8F22E1E6AFD30F_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5C54397FE57219429B8F22E1E6AFD30F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5C54397FE57219429B8F22E1E6AFD30F" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5C54397FE57219429B8F22E1E6AFD30F" xlink:type="arc" />
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    <link:label id="lab_us-gaap_DividendsCommonStockCash_815BCD01379018C013DE22E1E6AFDF16_label_en-US" xlink:label="lab_us-gaap_DividendsCommonStockCash_815BCD01379018C013DE22E1E6AFDF16" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends, Common Stock, Cash</link:label>
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    <link:label id="lab_noa_AdjustmentsToAdditionalPaidInCapitalRepurchaseOfSharesToSettleStockAwardPlan_172AB8E69EDEB3A3370522E1E6AF449D_negatedLabel_en-US" xlink:label="lab_noa_AdjustmentsToAdditionalPaidInCapitalRepurchaseOfSharesToSettleStockAwardPlan_172AB8E69EDEB3A3370522E1E6AF449D" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Share purchase programs (note 18(c))</link:label>
    <link:label id="lab_noa_AdjustmentsToAdditionalPaidInCapitalRepurchaseOfSharesToSettleStockAwardPlan_172AB8E69EDEB3A3370522E1E6AF449D_label_en-US" xlink:label="lab_noa_AdjustmentsToAdditionalPaidInCapitalRepurchaseOfSharesToSettleStockAwardPlan_172AB8E69EDEB3A3370522E1E6AF449D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustments To Additional Paid In Capital Repurchase Of Shares To Settle Stock Award Plan</link:label>
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    <link:label id="lab_us-gaap_TreasuryStockValueAcquiredCostMethod_12A3675DDD9DED45F28322E1E6AF5C7A_label_en-US" xlink:label="lab_us-gaap_TreasuryStockValueAcquiredCostMethod_12A3675DDD9DED45F28322E1E6AF5C7A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Treasury Stock, Value, Acquired, Cost Method</link:label>
    <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" />
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    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_B05349D82613F89D0AB222E1E6AF7B9D_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_B05349D82613F89D0AB222E1E6AF7B9D" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Conversion of Convertible Debentures (note 14(c))</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_B05349D82613F89D0AB222E1E6AF7B9D_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_B05349D82613F89D0AB222E1E6AF7B9D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Value, Conversion of Convertible Securities</link:label>
    <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:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_B05349D82613F89D0AB222E1E6AF7B9D" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_B05349D82613F89D0AB222E1E6AF7B9D" xlink:type="arc" />
    <link:label id="lab_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_74448CAB308FC271496022E1E6AF4519_terseLabel_en-US" xlink:label="lab_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_74448CAB308FC271496022E1E6AF4519" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Noncontrolling interest acquired in affiliates and joint ventures</link:label>
    <link:label id="lab_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_74448CAB308FC271496022E1E6AF4519_label_en-US" xlink:label="lab_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_74448CAB308FC271496022E1E6AF4519" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncontrolling Interest, Increase from Business Combination</link:label>
    <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" />
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    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_38C1AC92A2541369401422E1E6B02241_periodEndLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_38C1AC92A2541369401422E1E6B02241" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Ending balance</link:label>
    <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_38C1AC92A2541369401422E1E6B02241" xlink:type="locator" />
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    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligation_D51ADE5D5B454BA349151696771F50AF_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligation_D51ADE5D5B454BA349151696771F50AF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Remaining performance obligation</link:label>
    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligation_D51ADE5D5B454BA349151696771F50AF_label_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligation_D51ADE5D5B454BA349151696771F50AF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Remaining Performance Obligation, Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_D51ADE5D5B454BA349151696771F50AF" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligation_D51ADE5D5B454BA349151696771F50AF" xlink:to="lab_us-gaap_RevenueRemainingPerformanceObligation_D51ADE5D5B454BA349151696771F50AF" xlink:type="arc" />
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    <link:label id="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_5AB5586A944C272682421696771F1245_label_en-US" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_5AB5586A944C272682421696771F1245" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table]</link:label>
    <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" />
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    <link:label id="lab_noa_OtherLongTermReceivables_002024A16843B50481D90CF2760BDA38_terseLabel_en-US" xlink:label="lab_noa_OtherLongTermReceivables_002024A16843B50481D90CF2760BDA38" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other long term receivable</link:label>
    <link:label id="lab_noa_OtherLongTermReceivables_002024A16843B50481D90CF2760BDA38_label_en-US" xlink:label="lab_noa_OtherLongTermReceivables_002024A16843B50481D90CF2760BDA38" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Long-Term Receivables</link:label>
    <link:label id="lab_noa_OtherLongTermReceivables_002024A16843B50481D90CF2760BDA38_documentation_en-US" xlink:label="lab_noa_OtherLongTermReceivables_002024A16843B50481D90CF2760BDA38" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Long-Term Receivables</link:label>
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    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsNet_7E2032E7AC47E1C2841F0CF2760B044D_verboseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsNet_7E2032E7AC47E1C2841F0CF2760B044D" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Intangible assets</link:label>
    <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_7E2032E7AC47E1C2841F0CF2760B044D" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsNet_9CDB494A914799E7AFE20CF2760B0ADE_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtIssuanceCostsLineOfCreditArrangementsNet_9CDB494A914799E7AFE20CF2760B0ADE" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Deferred financing costs</link:label>
    <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_9CDB494A914799E7AFE20CF2760B0ADE" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LeaseIncentiveReceivableNoncurrent_FEBBD14022EF34AE06390CF2760BD9E5_terseLabel_en-US" xlink:label="lab_us-gaap_LeaseIncentiveReceivableNoncurrent_FEBBD14022EF34AE06390CF2760BD9E5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred lease inducement assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LeaseIncentiveReceivableNoncurrent" xlink:label="loc_us-gaap_LeaseIncentiveReceivableNoncurrent_FEBBD14022EF34AE06390CF2760BD9E5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseIncentiveReceivableNoncurrent_FEBBD14022EF34AE06390CF2760BD9E5" xlink:to="lab_us-gaap_LeaseIncentiveReceivableNoncurrent_FEBBD14022EF34AE06390CF2760BD9E5" xlink:type="arc" />
    <link:label id="lab_us-gaap_DueFromJointVentures_AB0FCD4FA67FEF9D92680CF2760C5181_terseLabel_en-US" xlink:label="lab_us-gaap_DueFromJointVentures_AB0FCD4FA67FEF9D92680CF2760C5181" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loan to DNSS</link:label>
    <link:label id="lab_us-gaap_DueFromJointVentures_AB0FCD4FA67FEF9D92680CF2760C5181_label_en-US" xlink:label="lab_us-gaap_DueFromJointVentures_AB0FCD4FA67FEF9D92680CF2760C5181" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Due from Joint Ventures</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DueFromJointVentures" xlink:label="loc_us-gaap_DueFromJointVentures_AB0FCD4FA67FEF9D92680CF2760C5181" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DueFromJointVentures_AB0FCD4FA67FEF9D92680CF2760C5181" xlink:to="lab_us-gaap_DueFromJointVentures_AB0FCD4FA67FEF9D92680CF2760C5181" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherAssetsNoncurrent_358E2EB41BB0A71C67AE0CF2760C676D_totalLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent_358E2EB41BB0A71C67AE0CF2760C676D" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total other assets, noncurrent</link:label>
    <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_358E2EB41BB0A71C67AE0CF2760C676D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsNoncurrent_358E2EB41BB0A71C67AE0CF2760C676D" xlink:to="lab_us-gaap_OtherAssetsNoncurrent_358E2EB41BB0A71C67AE0CF2760C676D" xlink:type="arc" />
    <link:label id="lab_noa_CashFlowNonCashTransactionsAbstract_AA3B5D1622EBE4849A89203712BECDA3_terseLabel_en-US" xlink:label="lab_noa_CashFlowNonCashTransactionsAbstract_AA3B5D1622EBE4849A89203712BECDA3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-cash transactions:</link:label>
    <link:label id="lab_noa_CashFlowNonCashTransactionsAbstract_AA3B5D1622EBE4849A89203712BECDA3_label_en-US" xlink:label="lab_noa_CashFlowNonCashTransactionsAbstract_AA3B5D1622EBE4849A89203712BECDA3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Flow, Non-cash Transactions [Abstract]</link:label>
    <link:label id="lab_noa_CashFlowNonCashTransactionsAbstract_AA3B5D1622EBE4849A89203712BECDA3_documentation_en-US" xlink:label="lab_noa_CashFlowNonCashTransactionsAbstract_AA3B5D1622EBE4849A89203712BECDA3" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash Flow, Non-cash Transactions [Abstract]</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_CashFlowNonCashTransactionsAbstract" xlink:label="loc_noa_CashFlowNonCashTransactionsAbstract_AA3B5D1622EBE4849A89203712BECDA3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_CashFlowNonCashTransactionsAbstract_AA3B5D1622EBE4849A89203712BECDA3" xlink:to="lab_noa_CashFlowNonCashTransactionsAbstract_AA3B5D1622EBE4849A89203712BECDA3" xlink:type="arc" />
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsAdditionOfPropertyPlantAndEquipment_85E6440B8EEB091F1840203712BEBD1C_terseLabel_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsAdditionOfPropertyPlantAndEquipment_85E6440B8EEB091F1840203712BEBD1C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Addition of property, plant and equipment by means of capital leases</link:label>
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    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsAdditionOfPropertyPlantAndEquipment_85E6440B8EEB091F1840203712BEBD1C_documentation_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsAdditionOfPropertyPlantAndEquipment_85E6440B8EEB091F1840203712BEBD1C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash Or Part Noncash Asset Acquisition, Capital Lease Obligations, Addition Of Property, Plant And Equipment</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsAdditionOfPropertyPlantAndEquipment" xlink:label="loc_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsAdditionOfPropertyPlantAndEquipment_85E6440B8EEB091F1840203712BEBD1C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsAdditionOfPropertyPlantAndEquipment_85E6440B8EEB091F1840203712BEBD1C" xlink:to="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsAdditionOfPropertyPlantAndEquipment_85E6440B8EEB091F1840203712BEBD1C" xlink:type="arc" />
    <link:label id="lab_noa_AdditionsToAssetsHeldForSale_36BE584CFFA6B43A6E27203712BF8287_negatedTerseLabel_en-US" xlink:label="lab_noa_AdditionsToAssetsHeldForSale_36BE584CFFA6B43A6E27203712BF8287" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment reclassified to asset held for sale</link:label>
    <link:label id="lab_noa_AdditionsToAssetsHeldForSale_36BE584CFFA6B43A6E27203712BF8287_label_en-US" xlink:label="lab_noa_AdditionsToAssetsHeldForSale_36BE584CFFA6B43A6E27203712BF8287" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additions to Assets Held for Sale</link:label>
    <link:label id="lab_noa_AdditionsToAssetsHeldForSale_36BE584CFFA6B43A6E27203712BF8287_documentation_en-US" xlink:label="lab_noa_AdditionsToAssetsHeldForSale_36BE584CFFA6B43A6E27203712BF8287" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Additions to Assets Held for Sale</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_AdditionsToAssetsHeldForSale" xlink:label="loc_noa_AdditionsToAssetsHeldForSale_36BE584CFFA6B43A6E27203712BF8287" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_AdditionsToAssetsHeldForSale_36BE584CFFA6B43A6E27203712BF8287" xlink:to="lab_noa_AdditionsToAssetsHeldForSale_36BE584CFFA6B43A6E27203712BF8287" xlink:type="arc" />
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment_4055A943D0FEFF3BF6A4203712BFC835_terseLabel_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment_4055A943D0FEFF3BF6A4203712BFC835" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase in capital lease obligations related to purchase of heavy equipment fleet and related assets</link:label>
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment_4055A943D0FEFF3BF6A4203712BFC835_label_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment_4055A943D0FEFF3BF6A4203712BFC835" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash Or Part Noncash Asset Acquisition, Capital Lease Obligations, Purchase Of Equipment</link:label>
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment_4055A943D0FEFF3BF6A4203712BFC835_documentation_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment_4055A943D0FEFF3BF6A4203712BFC835" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash Or Part Noncash Asset Acquisition, Capital Lease Obligations, Purchase Of Equipment</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment" xlink:label="loc_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment_4055A943D0FEFF3BF6A4203712BFC835" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment_4055A943D0FEFF3BF6A4203712BFC835" xlink:to="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsPurchaseOfEquipment_4055A943D0FEFF3BF6A4203712BFC835" xlink:type="arc" />
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures_240C3F091A01729B14E4203712BFEE0D_terseLabel_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures_240C3F091A01729B14E4203712BFEE0D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase in capital lease obligations related to investment in affiliates and joint ventures</link:label>
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures_240C3F091A01729B14E4203712BFEE0D_label_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures_240C3F091A01729B14E4203712BFEE0D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash Or Part Noncash Asset Acquisition, Capital Lease Obligations, Investment In Affiliates And Joint Ventures</link:label>
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures_240C3F091A01729B14E4203712BFEE0D_documentation_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures_240C3F091A01729B14E4203712BFEE0D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash Or Part Noncash Asset Acquisition, Capital Lease Obligations, Investment In Affiliates And Joint Ventures</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures" xlink:label="loc_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures_240C3F091A01729B14E4203712BFEE0D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures_240C3F091A01729B14E4203712BFEE0D" xlink:to="lab_noa_NoncashOrPartNoncashAssetAcquisitionCapitalLeaseObligationsInvestmentInAffiliatesAndJointVentures_240C3F091A01729B14E4203712BFEE0D" xlink:type="arc" />
    <link:label id="lab_noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership_68597A0E026D9DE5857F203712BF6856_terseLabel_en-US" xlink:label="lab_noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership_68597A0E026D9DE5857F203712BF6856" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase in capital lease obligations related to the initial investment in the partnership</link:label>
    <link:label id="lab_noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership_68597A0E026D9DE5857F203712BF6856_label_en-US" xlink:label="lab_noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership_68597A0E026D9DE5857F203712BF6856" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash or Part Noncash Acquisition, Capital Lease Obligations, Investment In Partnership</link:label>
    <link:label id="lab_noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership_68597A0E026D9DE5857F203712BF6856_documentation_en-US" xlink:label="lab_noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership_68597A0E026D9DE5857F203712BF6856" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash or Part Noncash Acquisition, Capital Lease Obligations, Investment In Partnership</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership" xlink:label="loc_noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership_68597A0E026D9DE5857F203712BF6856" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership_68597A0E026D9DE5857F203712BF6856" xlink:to="lab_noa_NoncashorPartNoncashAcquisitionCapitalLeaseObligationsInvestmentInPartnership_68597A0E026D9DE5857F203712BF6856" xlink:type="arc" />
    <link:label id="lab_noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase_0517340B72CE316AC462203712BF5BA8_terseLabel_en-US" xlink:label="lab_noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase_0517340B72CE316AC462203712BF5BA8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase in equipment promissory notes related to purchase of heavy equipment fleet and related assets</link:label>
    <link:label id="lab_noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase_0517340B72CE316AC462203712BF5BA8_label_en-US" xlink:label="lab_noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase_0517340B72CE316AC462203712BF5BA8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash or Part Noncash Acquisition, Debt Assumed, Equipment Purchase</link:label>
    <link:label id="lab_noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase_0517340B72CE316AC462203712BF5BA8_documentation_en-US" xlink:label="lab_noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase_0517340B72CE316AC462203712BF5BA8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash or Part Noncash Acquisition, Debt Assumed, Equipment Purchase</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase" xlink:label="loc_noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase_0517340B72CE316AC462203712BF5BA8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase_0517340B72CE316AC462203712BF5BA8" xlink:to="lab_noa_NoncashorPartNoncashAcquisitionDebtAssumedEquipmentPurchase_0517340B72CE316AC462203712BF5BA8" xlink:type="arc" />
    <link:label id="lab_us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_B3D84ECD7151E1067EB4203712BFEF3C_terseLabel_en-US" xlink:label="lab_us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_B3D84ECD7151E1067EB4203712BFEF3C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Acquisition of property, plant and equipment related to the initial investment in the partnership</link:label>
    <link:label id="lab_us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_B3D84ECD7151E1067EB4203712BFEF3C_label_en-US" xlink:label="lab_us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_B3D84ECD7151E1067EB4203712BFEF3C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash or Part Noncash Acquisition, Fixed Assets Acquired</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1" xlink:label="loc_us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_B3D84ECD7151E1067EB4203712BFEF3C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_B3D84ECD7151E1067EB4203712BFEF3C" xlink:to="lab_us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_B3D84ECD7151E1067EB4203712BFEF3C" xlink:type="arc" />
    <link:label id="lab_us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1_4DE549F675FE457BDD1A203712C08719_terseLabel_en-US" xlink:label="lab_us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1_4DE549F675FE457BDD1A203712C08719" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase in long term debt related to investment in affiliates and joint ventures</link:label>
    <link:label id="lab_us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1_4DE549F675FE457BDD1A203712C08719_label_en-US" xlink:label="lab_us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1_4DE549F675FE457BDD1A203712C08719" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash or Part Noncash Acquisition, Debt Assumed</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1" xlink:label="loc_us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1_4DE549F675FE457BDD1A203712C08719" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1_4DE549F675FE457BDD1A203712C08719" xlink:to="lab_us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1_4DE549F675FE457BDD1A203712C08719" xlink:type="arc" />
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed_675922E68E1F75B08B1E203712C04942_terseLabel_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed_675922E68E1F75B08B1E203712C04942" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase in long term debt related to investment in affiliates and joint ventures</link:label>
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed_675922E68E1F75B08B1E203712C04942_label_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed_675922E68E1F75B08B1E203712C04942" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash Or Part Noncash Asset Acquisition, Debt Assumed</link:label>
    <link:label id="lab_noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed_675922E68E1F75B08B1E203712C04942_documentation_en-US" xlink:label="lab_noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed_675922E68E1F75B08B1E203712C04942" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash Or Part Noncash Asset Acquisition, Debt Assumed</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed" xlink:label="loc_noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed_675922E68E1F75B08B1E203712C04942" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed_675922E68E1F75B08B1E203712C04942" xlink:to="lab_noa_NoncashOrPartNoncashAssetAcquisitionDebtAssumed_675922E68E1F75B08B1E203712C04942" xlink:type="arc" />
    <link:label id="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_40B02BDAC51820FEDF94203712C0A7B6_terseLabel_en-US" xlink:label="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_40B02BDAC51820FEDF94203712C0A7B6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-cash working capital exclusions:</link:label>
    <link:label id="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_40B02BDAC51820FEDF94203712C0A7B6_label_en-US" xlink:label="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_40B02BDAC51820FEDF94203712C0A7B6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:label="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_40B02BDAC51820FEDF94203712C0A7B6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_40B02BDAC51820FEDF94203712C0A7B6" xlink:to="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_40B02BDAC51820FEDF94203712C0A7B6" xlink:type="arc" />
    <link:label id="lab_noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement_9D94A3BB0704F2B865EC203712C00C57_terseLabel_en-US" xlink:label="lab_noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement_9D94A3BB0704F2B865EC203712C00C57" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Decrease in contract assets related to adoption of accounting standards</link:label>
    <link:label id="lab_noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement_9D94A3BB0704F2B865EC203712C00C57_label_en-US" xlink:label="lab_noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement_9D94A3BB0704F2B865EC203712C00C57" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Decrease In Contract With Customer, Asset, Due To Adoption Of Accounting Pronouncement</link:label>
    <link:label id="lab_noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement_9D94A3BB0704F2B865EC203712C00C57_documentation_en-US" xlink:label="lab_noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement_9D94A3BB0704F2B865EC203712C00C57" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Decrease In Contract With Customer, Asset, Due To Adoption Of Accounting Pronouncement</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement" xlink:label="loc_noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement_9D94A3BB0704F2B865EC203712C00C57" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement_9D94A3BB0704F2B865EC203712C00C57" xlink:to="lab_noa_DecreaseInContractWithCustomerAssetDueToAdoptionOfAccountingPronouncement_9D94A3BB0704F2B865EC203712C00C57" xlink:type="arc" />
    <link:label id="lab_us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1_1B5A1E3A611E2DAE3F43203712C0CC6F_terseLabel_en-US" xlink:label="lab_us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1_1B5A1E3A611E2DAE3F43203712C0CC6F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase in inventory related to the initial partnership investment</link:label>
    <link:label id="lab_us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1_1B5A1E3A611E2DAE3F43203712C0CC6F_label_en-US" xlink:label="lab_us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1_1B5A1E3A611E2DAE3F43203712C0CC6F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash or Part Noncash Acquisition, Inventory Acquired</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1" xlink:label="loc_us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1_1B5A1E3A611E2DAE3F43203712C0CC6F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1_1B5A1E3A611E2DAE3F43203712C0CC6F" xlink:to="lab_us-gaap_NoncashOrPartNoncashAcquisitionInventoryAcquired1_1B5A1E3A611E2DAE3F43203712C0CC6F" xlink:type="arc" />
    <link:label id="lab_noa_IncreaseInInventoriesDueToAssetAcquisitions_104E2E75EA6936708EB9203712C10D2A_negatedTerseLabel_en-US" xlink:label="lab_noa_IncreaseInInventoriesDueToAssetAcquisitions_104E2E75EA6936708EB9203712C10D2A" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Increase in inventory related to the purchase of heavy equipment fleet and related assets</link:label>
    <link:label id="lab_noa_IncreaseInInventoriesDueToAssetAcquisitions_104E2E75EA6936708EB9203712C10D2A_label_en-US" xlink:label="lab_noa_IncreaseInInventoriesDueToAssetAcquisitions_104E2E75EA6936708EB9203712C10D2A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase In Inventories Due To Asset Acquisitions</link:label>
    <link:label id="lab_noa_IncreaseInInventoriesDueToAssetAcquisitions_104E2E75EA6936708EB9203712C10D2A_documentation_en-US" xlink:label="lab_noa_IncreaseInInventoriesDueToAssetAcquisitions_104E2E75EA6936708EB9203712C10D2A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Increase In Inventories Due To Asset Acquisitions</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_IncreaseInInventoriesDueToAssetAcquisitions" xlink:label="loc_noa_IncreaseInInventoriesDueToAssetAcquisitions_104E2E75EA6936708EB9203712C10D2A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_IncreaseInInventoriesDueToAssetAcquisitions_104E2E75EA6936708EB9203712C10D2A" xlink:to="lab_noa_IncreaseInInventoriesDueToAssetAcquisitions_104E2E75EA6936708EB9203712C10D2A" xlink:type="arc" />
    <link:label id="lab_noa_NoncashorPartNoncashAcquisitionPrepaidExpense_3DCDB689D93522A6B7FA203712C1C8CD_negatedTerseLabel_en-US" xlink:label="lab_noa_NoncashorPartNoncashAcquisitionPrepaidExpense_3DCDB689D93522A6B7FA203712C1C8CD" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Increase in prepaid expenses related to the initial investment in the partnership</link:label>
    <link:label id="lab_noa_NoncashorPartNoncashAcquisitionPrepaidExpense_3DCDB689D93522A6B7FA203712C1C8CD_label_en-US" xlink:label="lab_noa_NoncashorPartNoncashAcquisitionPrepaidExpense_3DCDB689D93522A6B7FA203712C1C8CD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash or Part Noncash Acquisition Prepaid Expense</link:label>
    <link:label id="lab_noa_NoncashorPartNoncashAcquisitionPrepaidExpense_3DCDB689D93522A6B7FA203712C1C8CD_documentation_en-US" xlink:label="lab_noa_NoncashorPartNoncashAcquisitionPrepaidExpense_3DCDB689D93522A6B7FA203712C1C8CD" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash or Part Noncash Acquisition Prepaid Expense</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_NoncashorPartNoncashAcquisitionPrepaidExpense" xlink:label="loc_noa_NoncashorPartNoncashAcquisitionPrepaidExpense_3DCDB689D93522A6B7FA203712C1C8CD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_NoncashorPartNoncashAcquisitionPrepaidExpense_3DCDB689D93522A6B7FA203712C1C8CD" xlink:to="lab_noa_NoncashorPartNoncashAcquisitionPrepaidExpense_3DCDB689D93522A6B7FA203712C1C8CD" xlink:type="arc" />
    <link:label id="lab_noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement_1EFCFA132E58C815DA25203712C1FEE1_negatedTerseLabel_en-US" xlink:label="lab_noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement_1EFCFA132E58C815DA25203712C1FEE1" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Increase in other assets related to adoption of accounting standards</link:label>
    <link:label id="lab_noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement_1EFCFA132E58C815DA25203712C1FEE1_label_en-US" xlink:label="lab_noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement_1EFCFA132E58C815DA25203712C1FEE1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase In Other Assets Noncurrent Due To Adoption Of Accounting Pronouncement</link:label>
    <link:label id="lab_noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement_1EFCFA132E58C815DA25203712C1FEE1_documentation_en-US" xlink:label="lab_noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement_1EFCFA132E58C815DA25203712C1FEE1" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Increase In Other Assets Noncurrent Due To Adoption Of Accounting Pronouncement</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement" xlink:label="loc_noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement_1EFCFA132E58C815DA25203712C1FEE1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement_1EFCFA132E58C815DA25203712C1FEE1" xlink:to="lab_noa_IncreaseInOtherAssetsNoncurrentDueToAdoptionOfAccountingPronouncement_1EFCFA132E58C815DA25203712C1FEE1" xlink:type="arc" />
    <link:label id="lab_noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent_E3A39732E5113A3AD566203712C1E988_terseLabel_en-US" xlink:label="lab_noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent_E3A39732E5113A3AD566203712C1E988" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase in accrued liabilities related to the current portion of the deferred gain on sale-leaseback</link:label>
    <link:label id="lab_noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent_E3A39732E5113A3AD566203712C1E988_label_en-US" xlink:label="lab_noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent_E3A39732E5113A3AD566203712C1E988" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Noncash Transaction, Increase (Decrease) in Accrued Liabilities, Sale Leaseback, Current</link:label>
    <link:label id="lab_noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent_E3A39732E5113A3AD566203712C1E988_documentation_en-US" xlink:label="lab_noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent_E3A39732E5113A3AD566203712C1E988" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncash Transaction, Increase (Decrease) in Accrued Liabilities, Sale Leaseback, Current</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent" xlink:label="loc_noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent_E3A39732E5113A3AD566203712C1E988" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent_E3A39732E5113A3AD566203712C1E988" xlink:to="lab_noa_NoncashTransactionIncreaseDecreaseinAccruedLiabilitiesSaleLeasebackCurrent_E3A39732E5113A3AD566203712C1E988" xlink:type="arc" />
    <link:label id="lab_noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation_300214319CAC7C3C8E9C203712C15E2E_negatedTerseLabel_en-US" xlink:label="lab_noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation_300214319CAC7C3C8E9C203712C15E2E" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Decrease in accrued liabilities related to conversion of bonus compensation to deferred stock units</link:label>
    <link:label id="lab_noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation_300214319CAC7C3C8E9C203712C15E2E_label_en-US" xlink:label="lab_noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation_300214319CAC7C3C8E9C203712C15E2E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Decrease In Accrued Liabilities Due To Conversion Of Bonus Compensation</link:label>
    <link:label id="lab_noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation_300214319CAC7C3C8E9C203712C15E2E_documentation_en-US" xlink:label="lab_noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation_300214319CAC7C3C8E9C203712C15E2E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Decrease In Accrued Liabilities Due To Conversion Of Bonus Compensation</link:label>
    <link:loc xlink:href="noa-20181231.xsd#noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation" xlink:label="loc_noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation_300214319CAC7C3C8E9C203712C15E2E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation_300214319CAC7C3C8E9C203712C15E2E" xlink:to="lab_noa_DecreaseInAccruedLiabilitiesDueToConversionOfBonusCompensation_300214319CAC7C3C8E9C203712C15E2E" xlink:type="arc" />
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