SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:	12 Months Ended
Dec. 31, 2017
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:	NOTE 2—SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: Principles of consolidation— The consolidated financial statements include the accounts of subsidiaries of which the Company has voting control, in accordance with Accounting Standards Codification ("ASC") 810 Consolidation. Such financial statements are prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP"). Use of estimates— The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include the carrying value of ore reserves that are the basis for future cash flow estimates and amortization calculations; environmental reclamation, closure and retirement obligations; estimates of recoverable copper in mill and leach stockpiles; asset impairments (including estimates of future cash flows); unrecognized tax benefits; valuation allowances for deferred tax assets; and fair value of financial instruments. Management bases its estimates on the Company's historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Actual results could differ from those estimates. Revenue recognition— Substantially all of the Company's copper and non-copper products are sold under annual or other longer-term contracts. Revenue is recognized when title passes to the customer. The passing of title is based on terms of the contract, generally upon shipment. Copper and non-copper revenues are determined based on the monthly average of prevailing commodity prices according to the terms of the contracts. The Company provides allowances for doubtful accounts based upon historical bad debt and claims experience and periodic evaluation of specific customer accounts. For certain of the Company's sales of copper and molybdenum products, customer contracts allow for pricing based on a month subsequent to shipping, in most cases within the following three months and occasionally in some cases a few additional months. In such cases, revenue is recorded at a provisional price at the time of shipment. The provisionally priced copper sales are adjusted to reflect forward LME or COMEX copper prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract. In the case of molybdenum sales, for which there are no published forward prices, the provisionally priced sales are adjusted to reflect the market prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract. These provisional pricing arrangements are accounted for separately from the contract as an embedded derivative instrument under ASC 815-30 "Derivatives and Hedging—Cash Flow Hedges." The Company sells copper in concentrate, anode, blister and refined form at industry standard commercial terms. Net sales include the invoiced value of copper, zinc, silver, molybdenum, sulfuric acid and other metals and the corresponding fair value adjustment of the related forward contract of copper and molybdenum. Shipping and handling fees and costs— Amounts billed to customers for shipping and handling are classified as sales. Amounts incurred for shipping and handling are included in cost of sales (exclusive of depreciation, amortization and depletion). Cash and cash equivalents— Cash and cash equivalents include bank deposits, certificates of deposit and short-term investment funds with original maturities of three months or less at the date of purchase. The carrying value of cash and cash equivalents approximates fair value. Short-term investments— The Company accounts for short-term investments in accordance with ASC 320-10 "Investments Debt and Equity Securities—Recognition." The Company determines the appropriate classification of all short-term investments as held-to-maturity, available-for-sale or trading at the time of purchase and re-evaluates such classifications as of each balance sheet date. Unrealized gains and losses on available-for-sale investments, net of taxes, are reported as a component of accumulated other comprehensive income (loss) in stockholders' equity, unless such loss is deemed to be other than temporary. Inventories— The Company principally produces copper and, in the production process, obtains several by-products, including molybdenum, silver, zinc, sulfuric acid and other metals. Metal inventories, consisting of work-in-process and finished goods, are carried at the lower of average cost or market. Costs of work-in-process inventories and finished goods mainly include power, labor, fuel, operating and repair materials, depreciation, amortization, depletion, and other necessary costs related to the extraction and processing of ore, including mining, milling, concentrating, smelting, refining, leaching and chemical processing. Costs incurred in the production of metal inventories exclude general and administrative costs. Once molybdenum, silver, zinc and other by-products are identified, they are transferred to their respective production facilities and the incremental cost required to complete production is assigned to their inventory value. Work-in-process inventories represent materials that are in the process of being converted into a saleable product. Conversion processes vary depending on the nature of the copper ore and the specific mining operation. For sulfide ores, processing includes milling and concentrating and results in the production of copper and molybdenum concentrates. Finished goods include saleable products (e.g., copper concentrates, copper anodes, copper cathodes, copper rod, molybdenum concentrate and other metallurgical products). Supplies inventories are carried at the lower of average cost or market. Long-term inventory—Ore stockpiles on leach pads. The leaching process is an integral part of the mining operations carried out at the Company's open-pit mines. The Company capitalizes the production cost of leachable material at its Toquepala, La Caridad and Buenavista mines recognizing it as inventory. This cost includes mining and haulage costs incurred to deliver ore to leach pads, depreciation, amortization, depletion and site overhead costs. The estimates of recoverable mineral content contained in the leaching dumps are supported by engineering studies. As the production cycle of the leaching process is significantly longer than the conventional process of concentrating, smelting and electrolytic refining, the Company includes on its balance sheet current leach inventory (included in work-in-process inventories) and long-term leach inventory. Amortization of leachable material is recorded by the units of production method. Property— Property is recorded at acquisition cost, net of accumulated depreciation and amortization. Cost includes major expenditures for improvements and replacements, which extend useful lives or increase capacity and interest costs associated with significant capital additions. Maintenance, repairs, normal development costs at existing mines and gains or losses on assets retired or sold are reflected in earnings as incurred. Buildings and equipment are depreciated on the straight-line method over estimated lives from five to 40 years or the estimated life of the mine if shorter. Mine development— Mine development includes primarily the cost of acquiring land rights to an exploitable ore body, pre-production stripping costs at new mines that are commercially exploitable, costs associated with bringing new mineral properties into production, and removal of overburden to prepare unique and identifiable areas outside the current mining area for such future production. Mine development costs are amortized on a unit of production basis over the remaining life of the mines. There is a diversity of practices in the mining industry in the treatment of drilling and other related costs to delineate new ore reserves. The Company follows the practices outlined in the next two paragraphs in its treatment of drilling and related costs. Drilling and other associated costs incurred in the Company's efforts to delineate new resources, whether near-mine or Greenfield are expensed as incurred. These costs are classified as mineral exploration costs. Once the Company determines through feasibility studies that proven and probable reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs. These mine development costs incurred prospectively to develop the property are capitalized as incurred, until the commencement of production, and are amortized using the units of production method over estimated life of the ore body. During the production stage, drilling and other related costs incurred to maintain production are included in production cost in the period in which they are incurred. Drilling and other related costs incurred in the Company's efforts to delineate a major expansion of reserves at an existing production property are expensed as incurred. Once the Company determines through feasibility studies that proven and probable incremental reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs. These incremental mine development costs are capitalized as incurred, until the commencement of production and amortized using the units of production method over the estimated life of the ore body. A major expansion of reserves is one that increases total reserves at a property by approximately 10% or more. For the years ended December 31, 2017, 2016 and 2015, the Company did not capitalize any drilling and related costs. Asset retirement obligations (reclamation and remediation costs)— The fair value of a liability for asset retirement obligations is recognized in the period in which the liability is incurred. The liability is measured at fair value and is adjusted to its present value in subsequent periods as accretion expense is recorded. The corresponding asset retirement costs are capitalized as part of the carrying value of the related long-lived assets and depreciated over the asset's useful life. Intangible assets— Intangible assets include primarily the excess amount paid over the book value for investment shares which are presented as mining concessions, and mining and engineering development studies. Intangible assets are carried at acquisition costs, net of accumulated amortization and are amortized principally on a unit of production basis over the estimated remaining life of the mines. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. Debt issuance costs— Debt issuance costs related to a recognized debt liability are presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with the treatment of a debt discount. Ore reserves— The Company periodically reevaluates estimates of its ore reserves, which represent the Company's estimate as to the amount of unmined copper remaining in its existing mine locations that can be produced and sold at a profit. Such estimates are based on engineering evaluations derived from samples of drill holes and other openings, combined with assumptions about copper market prices and production costs at each of the respective mines. The Company updates its estimate of ore reserves at the beginning of each year. In this calculation, the Company uses current metal prices which are defined as the average metal price over the preceding three years. The current price per pound of copper, as defined, was $2.50, $2.61 and $2.99 at the end of 2017, 2016 and 2015, respectively. The ore reserve estimates are used to determine the amortization of mine development and intangible assets. Once the Company determines through feasibility studies that proven and probable reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs and the Company discloses the related ore reserves. Exploration— Tangible and intangible costs incurred in the search for mineral properties are charged against earnings when incurred. Income taxes— Provisions for income taxes are based on taxes payable or refundable for the current year and deferred taxes on temporary differences between the amount of taxable income and pretax financial income and between the tax bases of assets and liabilities and their reported amounts in the financial statements. Deferred tax assets and liabilities are included in the financial statements at currently enacted income tax rates applicable to the period in which the deferred tax assets and liabilities are expected to be realized and settled as prescribed in ASC 740 "Income taxes." As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. Deferred income tax assets are reduced by any benefits that, in the opinion of management, are more likely not to be realized. The Company's operations involve dealing with uncertainties and judgments in the application of complex tax regulations in multiple jurisdictions. The final taxes paid are dependent upon many factors, including negotiations with taxing authorities in various jurisdictions and resolution of disputes arising from federal, state, and international tax audits. The Company recognizes potential liabilities and records tax liabilities for anticipated tax audit issues in the U.S. and other tax jurisdictions based on its estimate of whether, and the extent to which, additional taxes will be due. The Company follows the guidance of ASC 740 "Income taxes" to record these liabilities. (See Note 7 "Income taxes" of the consolidated financial statements for additional information). The Company adjusts these reserves in light of changing facts and circumstances; however, due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from the Company's current estimate of the tax liabilities. If its estimate of tax liabilities proves to be less than the ultimate assessment, an additional charge to expense would result. If payment of these amounts ultimately proves to be less than the recorded amounts, the reversal of the liabilities would result in tax benefits being recognized in the period when the Company determines the liabilities are no longer necessary. The Company classifies income tax-related interest and penalties as income taxes in the financial statements, as well as interest and penalties, if any, related to unrecognized tax benefits. On December 22, 2017, the U.S. government enacted the "Tax Cuts and Jobs Act" (the "Act"). The Act contains numerous provisions, the following of which most significantly impact the Company: (i) a decrease in the corporate tax rate from 35% to 21%; (ii) a transition of the U.S. taxation of international operation from a worldwide system to a quasi-territorial system and a one-time transition tax on the mandatory deemed repatriation of cumulative foreign earnings as of December 31, 2017, (iii) generally eliminates U.S. federal income taxes on dividends from foreign subsidiaries, requiring a current inclusion in U.S. federal taxable income of certain earnings of controlled foreign corporations and (iv) limitations on the use of foreign tax credits to reduce the U.S. income tax liability. The U.S. Securities and Exchange Commission ("SEC") issued Staff Accounting Bulletin No. 118 ("SAB 118"), which provides guidance on accounting for the tax effects of the Act. The Company has adopted SAB 118. Accordingly, the provisions of the Act deemed most relevant to the Company have been considered in preparation of its financial statements as of December 31, 2017 based on the Company's best estimate. See further disclosure regarding the impacts of the Act and the adoption of SAB 118 in Note 7 to the accompanying consolidated financial statements. Foreign exchange— The Company's functional currency is the U.S. dollar. As required by local law, both the Peruvian Branch and Minera Mexico maintain their books of accounts in Peruvian soles and Mexican pesos, respectively. Foreign currency assets and liabilities are remeasured into U.S. dollars at current exchange rates, except for non-monetary items such as inventory, property, intangible assets and other assets which are remeasured at historical exchange rates. Revenues and expenses are generally translated at actual exchange rates in effect during the period, except for those items related to balance sheet amounts that are remeasured at historical exchange rates. Gains and losses from foreign currency remeasurement are included in earnings of the period. Gains and (losses) resulting from foreign currency transactions are included in "Cost of sales (exclusive of depreciation, amortization and depletion)." Asset impairments— The Company evaluates long-term assets when events or changes in economic circumstances indicate that the carrying amount of such assets may not be recoverable. These evaluations are based on business plans that are prepared using a time horizon that is reflective of the Company's expectations of metal prices over its business cycle. The Company is currently using a long-term average copper price and an average molybdenum price for impairment tests, reflective of what the Company believes is the lower level of the current price environment. The results of its impairment tests using these long-term copper and molybdenum prices show no impairment in the carrying value of their assets. In recent years testing using assumptions for long-term average prices have resulted in stricter evaluation for impairment analysis than would the higher three year average prices for copper and molybdenum prices. Should this situation reverse in the future with three year average prices below the long-term price assumption, the Company would assess the need to use the three year average prices in its evaluations. The Company uses an estimate of the future undiscounted net cash flows of the related asset or asset group over the remaining life to measure whether the assets are recoverable and measures any impairment by reference to fair value. Other comprehensive income— Comprehensive income represents changes in equity during a period, except those resulting from investments by owners and distributions to owners. During the fiscal years ended December 31, 2017, 2016 and 2015, the components of "other comprehensive income (loss)" were, the unrecognized gain (loss) on employee benefit obligations and foreign currency translation adjustments. Business segments— Company management views Southern Copper as having three reportable segments and manages it on the basis of these segments. The segments identified by the Company are: 1) the Peruvian operations, which include the two open-pit copper mines in Peru and the plants and services supporting such mines, 2) the Mexican open-pit copper mines, which include La Caridad and Buenavista mine complexes and their supporting facilities and 3) the Mexican underground mining operations, which include five underground mines that produce zinc, lead, copper, silver and gold, a coal mine and a zinc refinery. Please see Note 17 "Segments and Related Information." Senior management of the Company focus on operating income as measure of performance to evaluate different segments, and to make decisions to allocate resources to the reported segments. This is a common measure in the mining industry. ADOPTION OF REVENUE RECOGNITION STANDARD In May 2014, the FASB issued ASU 2014-09 "Revenue from Contracts with Customers" (Topic 606). The objective of the new revenue standard is to provide a single comprehensive revenue recognition model for all contracts with customers to improve comparability within industries, across industries and across capital markets. The core principle of the standard is that the Company should recognize revenue to represent the transfer of promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. The Company should apply the following five steps to achieve the core principle: Step 1: Identify the contract(s) with a customer. Step 2: Identify the performance obligations (promises) in the contract. Step 3: Determine the transaction price. Step 4: Allocate the transaction price to the performance obligations in the contract. Step 5: Recognize revenue when (or as) the Company satisfies a performance obligation. The guidance also specifies the accounting for some costs to obtain or fulfill a contract with a customer. Additionally, the Company should disclose sufficient qualitative and quantitative information to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. In March 2016, The FASB issued ASU 2016-08 Revenue from Contracts with Customers—(Topic 606) Principal versus Agent Considerations (Reporting Revenue Gross versus Net). This update clarifies the implementation guidance on principal versus agent considerations. When another party is involved in providing goods or services to a customer, an entity is required to determine whether the nature of its promise is to provide the specified good or service itself (that is, the entity is a principal) or to arrange for that good or service to be provided by the other party (that is, the entity is an agent). This revenue standard is effective for the first interim period within annual reporting periods beginning after December 15, 2017, and early adoption is not permitted. The Company has adopted the new guidance effective January 1, 2018, applying the modified retrospective approach. Under this approach, the results for reporting periods beginning after January 1, 2018 will be presented in the consolidated financial statements under the guidance, while prior period amounts will not be adjusted and will continue to be reported under the guidance in effect for those periods. Upon adoption by the Company, no cumulative effect adjustment is required to be recognized at January 1, 2018, as the adoption of the standard has not resulted in a change to the way the Company recognizes its revenue. The Company will apply the related disclosure requirements of the new standard beginning in 2018. OTHER NEW ACCOUNTING STANDARDS In January 2016, The FASB issued ASU 2016-01 "Financial instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities" which requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and to recognize any changes in fair value in net income. This update also includes certain disclosure requirements. This update is effective in fiscal years, including interim periods, beginning after December 15, 2017, and upon adoption, an entity should apply the amendments with the cumulative effect of initially applying the guidance recognized at January 1, 2018. Early adoption is not permitted. The Company has completed its assessment of the adoption of this standard and has determined that it will not have a material impact on its consolidated financial information. On February 25, 2016, the FASB issued ASU 2016-02 "Leases" (Topic 842). This Update significantly modifies the accounting model of leases for lessees; as it requires them to recognize assets and liabilities in the balance sheet for virtually all leases. However, the classification of leases as finance leases or operating leases is maintained for lessees. In addition, for leases with a term of 12 months or less, a lessee can elect by class of underlying asset not to record assets and liabilities on the balance sheet, and recognize lease expense on a straight-line basis over the lease term. The lessor accounting model for leases remains mostly unchanged from previous guidance, except for specific profit recognition requirements which were modified in order to align them to the new revenue recognition standard issued by the FASB, and the lease classification criteria, to ensure consistency with those for a lessee. The amendments in this Update are effective for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018 and early adoption is permitted. The Company is evaluating the impact of the adoption of this new standard on the consolidated financial information. In June 2016, the FASB issued ASU 2016-13 "Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments" This ASU amends guidance on reporting credit losses for assets held at amortized cost basis and available for sale debt securities and requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. For available for sale debt securities, credit losses should be measured in a manner similar to current GAAP, however Topic 326 will require that credit losses be presented as an allowance rather than as a write-down. This update is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company is evaluating the impact of the adoption of this new standard on the consolidated financial information. Other ASUs issued by the FASB that are pending adoption as of December 31, 2017 are not anticipated to have a significant impact on the Company's consolidated financial statements.

NOTE 2—SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:

Principles of consolidation—

The consolidated financial statements include the accounts of subsidiaries of which the Company has voting control, in accordance with Accounting Standards Codification ("ASC") 810 Consolidation. Such financial statements are prepared in accordance with accounting principles generally accepted in the United States ("U.S. GAAP").

Use of estimates—

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include the carrying value of ore reserves that are the basis for future cash flow estimates and amortization calculations; environmental reclamation, closure and retirement obligations; estimates of recoverable copper in mill and leach stockpiles; asset impairments (including estimates of future cash flows); unrecognized tax benefits; valuation allowances for deferred tax assets; and fair value of financial instruments. Management bases its estimates on the Company's historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Actual results could differ from those estimates.

Revenue recognition—

Substantially all of the Company's copper and non-copper products are sold under annual or other longer-term contracts.

Revenue is recognized when title passes to the customer. The passing of title is based on terms of the contract, generally upon shipment. Copper and non-copper revenues are determined based on the monthly average of prevailing commodity prices according to the terms of the contracts. The Company provides allowances for doubtful accounts based upon historical bad debt and claims experience and periodic evaluation of specific customer accounts.

For certain of the Company's sales of copper and molybdenum products, customer contracts allow for pricing based on a month subsequent to shipping, in most cases within the following three months and occasionally in some cases a few additional months. In such cases, revenue is recorded at a provisional price at the time of shipment. The provisionally priced copper sales are adjusted to reflect forward LME or COMEX copper prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract. In the case of molybdenum sales, for which there are no published forward prices, the provisionally priced sales are adjusted to reflect the market prices at the end of each month until a final adjustment is made to the price of the shipments upon settlement with customers pursuant to the terms of the contract.

These provisional pricing arrangements are accounted for separately from the contract as an embedded derivative instrument under ASC 815-30 "Derivatives and Hedging—Cash Flow Hedges." The Company sells copper in concentrate, anode, blister and refined form at industry standard commercial terms. Net sales include the invoiced value of copper, zinc, silver, molybdenum, sulfuric acid and other metals and the corresponding fair value adjustment of the related forward contract of copper and molybdenum.

Shipping and handling fees and costs—

Amounts billed to customers for shipping and handling are classified as sales. Amounts incurred for shipping and handling are included in cost of sales (exclusive of depreciation, amortization and depletion).

Cash and cash equivalents—

Cash and cash equivalents include bank deposits, certificates of deposit and short-term investment funds with original maturities of three months or less at the date of purchase. The carrying value of cash and cash equivalents approximates fair value.

Short-term investments—

The Company accounts for short-term investments in accordance with ASC 320-10 "Investments Debt and Equity Securities—Recognition." The Company determines the appropriate classification of all short-term investments as held-to-maturity, available-for-sale or trading at the time of purchase and re-evaluates such classifications as of each balance sheet date. Unrealized gains and losses on available-for-sale investments, net of taxes, are reported as a component of accumulated other comprehensive income (loss) in stockholders' equity, unless such loss is deemed to be other than temporary.

Inventories—

The Company principally produces copper and, in the production process, obtains several by-products, including molybdenum, silver, zinc, sulfuric acid and other metals.

Metal inventories, consisting of work-in-process and finished goods, are carried at the lower of average cost or market. Costs of work-in-process inventories and finished goods mainly include power, labor, fuel, operating and repair materials, depreciation, amortization, depletion, and other necessary costs related to the extraction and processing of ore, including mining, milling, concentrating, smelting, refining, leaching and chemical processing. Costs incurred in the production of metal inventories exclude general and administrative costs. Once molybdenum, silver, zinc and other by-products are identified, they are transferred to their respective production facilities and the incremental cost required to complete production is assigned to their inventory value.

Work-in-process inventories represent materials that are in the process of being converted into a saleable product. Conversion processes vary depending on the nature of the copper ore and the specific mining operation. For sulfide ores, processing includes milling and concentrating and results in the production of copper and molybdenum concentrates.

Finished goods include saleable products (e.g., copper concentrates, copper anodes, copper cathodes, copper rod, molybdenum concentrate and other metallurgical products).

Supplies inventories are carried at the lower of average cost or market.

Long-term inventory—Ore stockpiles on leach pads.

The leaching process is an integral part of the mining operations carried out at the Company's open-pit mines. The Company capitalizes the production cost of leachable material at its Toquepala, La Caridad and Buenavista mines recognizing it as inventory. This cost includes mining and haulage costs incurred to deliver ore to leach pads, depreciation, amortization, depletion and site overhead costs. The estimates of recoverable mineral content contained in the leaching dumps are supported by engineering studies. As the production cycle of the leaching process is significantly longer than the conventional process of concentrating, smelting and electrolytic refining, the Company includes on its balance sheet current leach inventory (included in work-in-process inventories) and long-term leach inventory. Amortization of leachable material is recorded by the units of production method.

Property—

Property is recorded at acquisition cost, net of accumulated depreciation and amortization. Cost includes major expenditures for improvements and replacements, which extend useful lives or increase capacity and interest costs associated with significant capital additions. Maintenance, repairs, normal development costs at existing mines and gains or losses on assets retired or sold are reflected in earnings as incurred.

Buildings and equipment are depreciated on the straight-line method over estimated lives from five to 40 years or the estimated life of the mine if shorter.

Mine development—

Mine development includes primarily the cost of acquiring land rights to an exploitable ore body, pre-production stripping costs at new mines that are commercially exploitable, costs associated with bringing new mineral properties into production, and removal of overburden to prepare unique and identifiable areas outside the current mining area for such future production. Mine development costs are amortized on a unit of production basis over the remaining life of the mines.

There is a diversity of practices in the mining industry in the treatment of drilling and other related costs to delineate new ore reserves. The Company follows the practices outlined in the next two paragraphs in its treatment of drilling and related costs.

Drilling and other associated costs incurred in the Company's efforts to delineate new resources, whether near-mine or Greenfield are expensed as incurred. These costs are classified as mineral exploration costs. Once the Company determines through feasibility studies that proven and probable reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs. These mine development costs incurred prospectively to develop the property are capitalized as incurred, until the commencement of production, and are amortized using the units of production method over estimated life of the ore body. During the production stage, drilling and other related costs incurred to maintain production are included in production cost in the period in which they are incurred.

Drilling and other related costs incurred in the Company's efforts to delineate a major expansion of reserves at an existing production property are expensed as incurred. Once the Company determines through feasibility studies that proven and probable incremental reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs. These incremental mine development costs are capitalized as incurred, until the commencement of production and amortized using the units of production method over the estimated life of the ore body. A major expansion of reserves is one that increases total reserves at a property by approximately 10% or more.

For the years ended December 31, 2017, 2016 and 2015, the Company did not capitalize any drilling and related costs.

Asset retirement obligations (reclamation and remediation costs)—

The fair value of a liability for asset retirement obligations is recognized in the period in which the liability is incurred. The liability is measured at fair value and is adjusted to its present value in subsequent periods as accretion expense is recorded. The corresponding asset retirement costs are capitalized as part of the carrying value of the related long-lived assets and depreciated over the asset's useful life.

Intangible assets—

Intangible assets include primarily the excess amount paid over the book value for investment shares which are presented as mining concessions, and mining and engineering development studies. Intangible assets are carried at acquisition costs, net of accumulated amortization and are amortized principally on a unit of production basis over the estimated remaining life of the mines. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable.

Debt issuance costs—

Debt issuance costs related to a recognized debt liability are presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with the treatment of a debt discount.

Ore reserves—

The Company periodically reevaluates estimates of its ore reserves, which represent the Company's estimate as to the amount of unmined copper remaining in its existing mine locations that can be produced and sold at a profit. Such estimates are based on engineering evaluations derived from samples of drill holes and other openings, combined with assumptions about copper market prices and production costs at each of the respective mines.

The Company updates its estimate of ore reserves at the beginning of each year. In this calculation, the Company uses current metal prices which are defined as the average metal price over the preceding three years. The current price per pound of copper, as defined, was $2.50, $2.61 and $2.99 at the end of 2017, 2016 and 2015, respectively. The ore reserve estimates are used to determine the amortization of mine development and intangible assets.

Once the Company determines through feasibility studies that proven and probable reserves exist and that the drilling and other associated costs embody a probable future benefit that involves a capacity, singly or in combination with other assets, to contribute directly or indirectly to future net cash inflow, then the costs are classified as mine development costs and the Company discloses the related ore reserves.

Exploration—

Tangible and intangible costs incurred in the search for mineral properties are charged against earnings when incurred.

Income taxes—

Provisions for income taxes are based on taxes payable or refundable for the current year and deferred taxes on temporary differences between the amount of taxable income and pretax financial income and between the tax bases of assets and liabilities and their reported amounts in the financial statements. Deferred tax assets and liabilities are included in the financial statements at currently enacted income tax rates applicable to the period in which the deferred tax assets and liabilities are expected to be realized and settled as prescribed in ASC 740 "Income taxes." As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. Deferred income tax assets are reduced by any benefits that, in the opinion of management, are more likely not to be realized.

The Company's operations involve dealing with uncertainties and judgments in the application of complex tax regulations in multiple jurisdictions. The final taxes paid are dependent upon many factors, including negotiations with taxing authorities in various jurisdictions and resolution of disputes arising from federal, state, and international tax audits. The Company recognizes potential liabilities and records tax liabilities for anticipated tax audit issues in the U.S. and other tax jurisdictions based on its estimate of whether, and the extent to which, additional taxes will be due. The Company follows the guidance of ASC 740 "Income taxes" to record these liabilities. (See Note 7 "Income taxes" of the consolidated financial statements for additional information). The Company adjusts these reserves in light of changing facts and circumstances; however, due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from the Company's current estimate of the tax liabilities. If its estimate of tax liabilities proves to be less than the ultimate assessment, an additional charge to expense would result. If payment of these amounts ultimately proves to be less than the recorded amounts, the reversal of the liabilities would result in tax benefits being recognized in the period when the Company determines the liabilities are no longer necessary.

The Company classifies income tax-related interest and penalties as income taxes in the financial statements, as well as interest and penalties, if any, related to unrecognized tax benefits.

On December 22, 2017, the U.S. government enacted the "Tax Cuts and Jobs Act" (the "Act"). The Act contains numerous provisions, the following of which most significantly impact the Company: (i) a decrease in the corporate tax rate from 35% to 21%; (ii) a transition of the U.S. taxation of international operation from a worldwide system to a quasi-territorial system and a one-time transition tax on the mandatory deemed repatriation of cumulative foreign earnings as of December 31, 2017, (iii) generally eliminates U.S. federal income taxes on dividends from foreign subsidiaries, requiring a current inclusion in U.S. federal taxable income of certain earnings of controlled foreign corporations and (iv) limitations on the use of foreign tax credits to reduce the U.S. income tax liability.

The U.S. Securities and Exchange Commission ("SEC") issued Staff Accounting Bulletin No. 118 ("SAB 118"), which provides guidance on accounting for the tax effects of the Act. The Company has adopted SAB 118. Accordingly, the provisions of the Act deemed most relevant to the Company have been considered in preparation of its financial statements as of December 31, 2017 based on the Company's best estimate. See further disclosure regarding the impacts of the Act and the adoption of SAB 118 in Note 7 to the accompanying consolidated financial statements.

Foreign exchange—

The Company's functional currency is the U.S. dollar. As required by local law, both the Peruvian Branch and Minera Mexico maintain their books of accounts in Peruvian soles and Mexican pesos, respectively.

Foreign currency assets and liabilities are remeasured into U.S. dollars at current exchange rates, except for non-monetary items such as inventory, property, intangible assets and other assets which are remeasured at historical exchange rates. Revenues and expenses are generally translated at actual exchange rates in effect during the period, except for those items related to balance sheet amounts that are remeasured at historical exchange rates. Gains and losses from foreign currency remeasurement are included in earnings of the period.

Gains and (losses) resulting from foreign currency transactions are included in "Cost of sales (exclusive of depreciation, amortization and depletion)."

Asset impairments—

The Company evaluates long-term assets when events or changes in economic circumstances indicate that the carrying amount of such assets may not be recoverable. These evaluations are based on business plans that are prepared using a time horizon that is reflective of the Company's expectations of metal prices over its business cycle. The Company is currently using a long-term average copper price and an average molybdenum price for impairment tests, reflective of what the Company believes is the lower level of the current price environment. The results of its impairment tests using these long-term copper and molybdenum prices show no impairment in the carrying value of their assets.

In recent years testing using assumptions for long-term average prices have resulted in stricter evaluation for impairment analysis than would the higher three year average prices for copper and molybdenum prices. Should this situation reverse in the future with three year average prices below the long-term price assumption, the Company would assess the need to use the three year average prices in its evaluations. The Company uses an estimate of the future undiscounted net cash flows of the related asset or asset group over the remaining life to measure whether the assets are recoverable and measures any impairment by reference to fair value.

Other comprehensive income—

Comprehensive income represents changes in equity during a period, except those resulting from investments by owners and distributions to owners. During the fiscal years ended December 31, 2017, 2016 and 2015, the components of "other comprehensive income (loss)" were, the unrecognized gain (loss) on employee benefit obligations and foreign currency translation adjustments.

Business segments—

Company management views Southern Copper as having three reportable segments and manages it on the basis of these segments. The segments identified by the Company are: 1) the Peruvian operations, which include the two open-pit copper mines in Peru and the plants and services supporting such mines, 2) the Mexican open-pit copper mines, which include La Caridad and Buenavista mine complexes and their supporting facilities and 3) the Mexican underground mining operations, which include five underground mines that produce zinc, lead, copper, silver and gold, a coal mine and a zinc refinery. Please see Note 17 "Segments and Related Information."

Senior management of the Company focus on operating income as measure of performance to evaluate different segments, and to make decisions to allocate resources to the reported segments. This is a common measure in the mining industry.

ADOPTION OF REVENUE RECOGNITION STANDARD

In May 2014, the FASB issued ASU 2014-09 "Revenue from Contracts with Customers" (Topic 606). The objective of the new revenue standard is to provide a single comprehensive revenue recognition model for all contracts with customers to improve comparability within industries, across industries and across capital markets.

The core principle of the standard is that the Company should recognize revenue to represent the transfer of promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services.

The Company should apply the following five steps to achieve the core principle:

Step 1: Identify the contract(s) with a customer.
Step 2: Identify the performance obligations (promises) in the contract.
Step 3: Determine the transaction price.
Step 4: Allocate the transaction price to the performance obligations in the contract.
Step 5: Recognize revenue when (or as) the Company satisfies a performance obligation.

The guidance also specifies the accounting for some costs to obtain or fulfill a contract with a customer. Additionally, the Company should disclose sufficient qualitative and quantitative information to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers.

In March 2016, The FASB issued ASU 2016-08 Revenue from Contracts with Customers—(Topic 606) Principal versus Agent Considerations (Reporting Revenue Gross versus Net). This update clarifies the implementation guidance on principal versus agent considerations. When another party is involved in providing goods or services to a customer, an entity is required to determine whether the nature of its promise is to provide the specified good or service itself (that is, the entity is a principal) or to arrange for that good or service to be provided by the other party (that is, the entity is an agent).

This revenue standard is effective for the first interim period within annual reporting periods beginning after December 15, 2017, and early adoption is not permitted. The Company has adopted the new guidance effective January 1, 2018, applying the modified retrospective approach. Under this approach, the results for reporting periods beginning after January 1, 2018 will be presented in the consolidated financial statements under the guidance, while prior period amounts will not be adjusted and will continue to be reported under the guidance in effect for those periods. Upon adoption by the Company, no cumulative effect adjustment is required to be recognized at January 1, 2018, as the adoption of the standard has not resulted in a change to the way the Company recognizes its revenue. The Company will apply the related disclosure requirements of the new standard beginning in 2018.

OTHER NEW ACCOUNTING STANDARDS

In January 2016, The FASB issued ASU 2016-01 "Financial instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities" which requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and to recognize any changes in fair value in net income. This update also includes certain disclosure requirements. This update is effective in fiscal years, including interim periods, beginning after December 15, 2017, and upon adoption, an entity should apply the amendments with the cumulative effect of initially applying the guidance recognized at January 1, 2018. Early adoption is not permitted. The Company has completed its assessment of the adoption of this standard and has determined that it will not have a material impact on its consolidated financial information.

On February 25, 2016, the FASB issued ASU 2016-02 "Leases" (Topic 842). This Update significantly modifies the accounting model of leases for lessees; as it requires them to recognize assets and liabilities in the balance sheet for virtually all leases. However, the classification of leases as finance leases or operating leases is maintained for lessees. In addition, for leases with a term of 12 months or less, a lessee can elect by class of underlying asset not to record assets and liabilities on the balance sheet, and recognize lease expense on a straight-line basis over the lease term.

The lessor accounting model for leases remains mostly unchanged from previous guidance, except for specific profit recognition requirements which were modified in order to align them to the new revenue recognition standard issued by the FASB, and the lease classification criteria, to ensure consistency with those for a lessee.

The amendments in this Update are effective for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018 and early adoption is permitted. The Company is evaluating the impact of the adoption of this new standard on the consolidated financial information.

In June 2016, the FASB issued ASU 2016-13 "Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments" This ASU amends guidance on reporting credit losses for assets held at amortized cost basis and available for sale debt securities and requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. For available for sale debt securities, credit losses should be measured in a manner similar to current GAAP, however Topic 326 will require that credit losses be presented as an allowance rather than as a write-down.

This update is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company is evaluating the impact of the adoption of this new standard on the consolidated financial information.

Other ASUs issued by the FASB that are pending adoption as of December 31, 2017 are not anticipated to have a significant impact on the Company's consolidated financial statements.