Notes to Consolidated Financial Statements  Years ended December 31, 2012 and 2011 4. Critical Accounting Estimates and Judgments (continued)  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 financial statements. 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. We also evaluate the recoverability of deferred tax assets based on an assessment of the 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 and joint ventures 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, operating costs, decommissioning and restoration  costs, capital expenditures, dividends and other capital management transactions. Judgment is also required about  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. In April 2012, we acquired SilverBirch Energy Corporation (“SilverBirch”) by way of a plan of arrangement for a net  cash outlay of $432 million. Under the arrangement, substantially all of SilverBirch’s assets, other than its 50% interest  in the Frontier and Equinox oil sands projects, were transferred into a new company, SilverWillow Energy Corporation  (“SilverWillow”). As part of the arrangement, we also transferred to SilverWillow our 50% interest in certain other oil  sands leases that were jointly owned with SilverBirch. SilverBirch shareholders, with the exception of Teck, received  $8.50 in cash and one share of SilverWillow for each SilverBirch common share. This acquisition provided us with  a 100% interest in the Frontier and Equinox oil sands projects and 4.7 million common shares (8.7%) of SilverWillow. 5. Acquisitions and Dispositions We recorded the purchase at $493 million, which was the fair value of the consideration paid, using $415 million of  cash, $25 million in working capital contributed to SilverWillow, $12 million of oil sands leases contributed to SilverWillow,  $40 million of SilverBirch shares that we owned prior to the transaction and $1 million in transaction costs. We accounted for this transaction as an acquisition of assets and have allocated the cost to the assets based on their  relative fair values at the date of purchase. The oil sand leases acquired are recorded as exploration and evaluation costs  within property, plant and equipment. The shares of SilverWillow are recorded as investments in marketable securities,  which are designated as available for sale financial assets and measured at fair value. In May 2011, we sold our 34% interest in the Carrapateena project in Southern Australia to an affiliate of Oz Minerals  Ltd. We received cash proceeds of US$134 million and may receive future contingent payments of up to US$25 million  based on future production from the property. The transaction resulted in a pre-tax gain of $110 million, which did not  include any value attributed to the contingent consideration. a) Completed Acquisition in 2012 b) Completed Disposition in 2011 Teck 2012 Annual Report 94