4.	Critical Accounting Estimates and Judgments

In preparing these consolidated financial statements, we make estimates and judgments that affect the amounts recorded. Actual results could differ from our estimates. Our estimates and judgments are based on historical experience and other factors we consider to be reasonable, including expectations of future events. The judgments and other sources of estimation uncertainty that have a risk of resulting in a material adjustment to the carrying amounts of assets and liabilities within the next year are outlined below.

Impairment Testing

Judgment is required in assessing whether certain factors would be considered an indicator of impairment or impairment reversal. We consider both internal and external information to determine whether there is an indicator of impairment or impairment reversal present and, accordingly, whether impairment testing is required. When impairment testing is required, discounted cash flow models are used to determine the recoverable amount of respective assets. These models are prepared internally with assistance from third-party advisors when required. When market transactions for comparable assets are available, these are considered in determining the recoverable amount of assets. Significant assumptions used in preparing discounted cash flow models include commodity prices, reserves and resources, mine plans, operating costs, capital expenditures, discount rates, foreign exchange rates and inflation rates. Note 6 outlines the significant inputs used when performing goodwill and other asset impairment testing. These inputs are based on management’s best estimates of what an independent market participant would consider appropriate. Changes in these inputs may alter the results of impairment testing, the amount of the impairment charges or reversals recorded in the statement of income and the resulting carrying values of assets.

Property, Plant and Equipment – Determination of Available for Use Date

Judgment is required in determining the date that property, plant and equipment is available for use. An asset is available for use when it is in the location and condition necessary to operate in the manner intended by management, and at that time, we commence depreciation of the asset and cease capitalization of borrowing costs. We consider a number of factors in making the determination of when an asset is available for use including, but not limited to, design capacity of the asset, production levels achieved, capital spending remaining and commissioning status. The Fort Hills oil sands project produced first oil in January 2018. We expect the project to be available for use, as defined above, in the first half of 2018.

Joint Arrangements

We are a party to a number of arrangements over which we do not have control. Judgment is required in determining whether joint control over these arrangements exists and, if so, which parties have joint control and whether each arrangement is a joint venture or joint operation. In assessing whether we have joint control, we analyze the activities of each arrangement and determine which activities most significantly affect the returns of the arrangement over its life. These activities are determined to be the relevant activities of the arrangement. If unanimous consent is required over the decisions about the relevant activities, the parties whose consent is required would have joint control over the arrangement. The judgments around which activities are considered the relevant activities of the arrangement are subject to analysis by each of the parties to the arrangement and may be interpreted differently. When performing this assessment, we generally consider decisions about activities such as managing the asset while it is being designed, developed and constructed, during its operating life and during the closure period. We may also consider other activities including the approval of budgets, expansion and disposition of assets, financing, significant operating and capital expenditures, appointment of key management personnel, representation on the board of directors and other items. When circumstances or contractual terms change, we reassess the control group and the relevant activities of the arrangement.

If we have joint control over the arrangement, an assessment of whether the arrangement is a joint venture or joint operation is required. This assessment is based on whether we have rights to the assets, and obligations for the liabilities, relating to the arrangement or whether we have rights to the net assets of the arrangement. In making this determination, we review the legal form of the arrangement, the terms of the contractual arrangement and other facts and circumstances. In a situation where the legal form and the terms of the contractual arrangement do not give us rights to the assets and obligations for the liabilities, an assessment of other facts and circumstances is required, including whether the activities of the arrangement are primarily designed for the provision of output to the parties and whether the parties are substantially the only source of cash flows contributing to the arrangement. In such circumstances, we may consider the application of other facts and circumstances to conclude that a joint arrangement is a joint operation. This conclusion requires judgment and is specific to each arrangement. Other facts and circumstances have led us to conclude that Antamina and Fort Hills are joint operations for the purposes of our consolidated financial statements. The other facts and circumstances considered for both of these arrangements are the provisions for output to the parties of the joint arrangements. For both Antamina and Fort Hills, we will take our share of the output from the assets directly over the life of the arrangement. We have concluded that this, combined with other factors, gives us direct rights to the assets and obligations for the liabilities of these arrangements, proportionate to our ownership interests.

Streaming Transactions

When we enter into a long-term streaming arrangement linked to production at specific operations, judgment is required in assessing the appropriate accounting treatment for the transaction on the closing date and in future periods. We consider the specific terms of each arrangement to determine whether we have disposed of an interest in the reserves and resources of the respective operation. This assessment considers what the counterparty is entitled to and the associated risks and rewards attributable to them over the life of the operation. These include the contractual terms related to the total production over the life of the arrangement as compared to the expected production over the life of the mine, the percentage being sold, the percentage of payable metals produced, the commodity price referred to in the ongoing payment and any guarantee relating to the upfront payment if production ceases.

For our silver and gold streaming arrangements entered into in 2015, there is no guarantee associated with the upfront payment, and we have concluded that we have effectively disposed of the interest in the silver and gold mineral interests at Antamina and Carmen de Andacollo, respectively. Accordingly, we consider these arrangements a disposition of a mineral interest.

When the ongoing payment we receive is based on future commodity prices at the date deliveries are made, this may be considered an embedded derivative (Note 28(c)). The valuation of embedded derivatives in these arrangements is an area of estimation and is determined using discounted cash flow models. These models require a variety of inputs, including, but not limited to, contractual terms, market prices, forward curve prices, mine plans and discount rates. Changes in these assumptions could affect the carrying value of derivative assets or liabilities and the amount of unrealized gains or losses recognized in other operating income (expense).

Estimated Recoverable Reserves and Resources

Mineral reserve and resource estimates are based on various assumptions relating to operating matters as set forth in National Instrument 43-101, Standards of Disclosure for Mineral Projects and National Instrument 51-101, Standards of Disclosure for Oil and Gas Activities. These include production costs, mining and processing recoveries, cut-off grades, long-term commodity prices and, in some cases, exchange rates, inflation rates and capital costs. Cost estimates are based on feasibility study estimates or operating history. Estimates are prepared by appropriately qualified persons, but will be affected by forecasted commodity prices, inflation rates, exchange rates, capital and production costs, and recoveries, among other factors. Estimated recoverable reserves and resources are used to determine the depreciation of property, plant and equipment at operating mine sites, in accounting for capitalized production stripping costs, in performing impairment testing, and in forecasting the timing of the payment of decommissioning and restoration costs. Therefore, changes in the assumptions used could affect the carrying value of assets, depreciation and impairment charges recorded in the statement of income and the carrying value of the decommissioning and restoration provision.

Decommissioning and Restoration Provisions

The decommissioning and restoration provision (DRP) is based on future cost estimates using information available at the balance sheet date (Note 22(a)). The DRP represents the present value of estimated costs of future decommissioning and other site restoration activities. The DRP is adjusted at each reporting period for changes to factors such as the expected amount of cash flows required to discharge the liability, the timing of such cash flows and the credit adjusted discount rate. The decommissioning and restoration provision requires other significant estimates and assumptions, including the requirements of the relevant legal and regulatory framework and the timing, extent and costs of required decommissioning and restoration activities. To the extent the actual costs differ from these estimates, adjustments will be recorded and the income statement may be affected.

During the year ended December 31, 2017, we updated our cost estimates for water quality management in the Elk Valley, including post-closure water quality management costs. These updates have increased our DRP for water quality management at Teck Coal to $394 million, which is an increase of approximately $244 million compared to December 31, 2016. The DRP includes water quality management costs based on mining activities up to December 31, 2017 and does not incorporate future mining activities. The water quality management costs included in our DRP extend for periods up to 100 years and are discounted using a nominal discount rate of 6.82% as at December 31, 2017. The cash flow estimates are inflated at a rate of 2.00%.

Current and Deferred Taxes

We calculate current and deferred tax provisions for each of the jurisdictions in which we operate. Actual amounts of income tax expense are not final until tax returns are filed and accepted by the relevant authorities. This occurs subsequent to the issuance of our financial statements, and the final determination of actual amounts may not be completed for a number of years. Therefore, profit in subsequent periods will be affected by the amount that estimates differ from the final tax return.

Judgment is required in assessing whether deferred tax assets and certain deferred tax liabilities are recognized on the balance sheet and what tax rate is expected to be applied in the year when the related temporary differences reverse, particularly in regard to the utilization of tax loss carry-forwards. We also evaluate the recoverability of deferred tax assets based on an assessment of our ability to use the underlying future tax deductions before they expire against future taxable income. Deferred tax liabilities arising from temporary differences on investments in subsidiaries, joint ventures and associates are recognized unless the reversal of the temporary differences is not expected to occur in the foreseeable future and can be controlled. Assumptions about the generation of future taxable profits and repatriation of retained earnings depend on management’s estimates of future production and sales volumes, commodity prices, reserves and resources, operating costs, decommissioning and restoration costs, capital expenditures, dividends and other capital management transactions. Judgment is also required on the application of income tax legislation. These estimates and judgments are subject to risk and uncertainty and could result in an adjustment to the deferred tax provision and a corresponding credit or charge to profit.