Production Stripping Costs Control Activities Business Activities, Key Performance Measures and Information Systems Outstanding Share Data Teck 2012 Annual Report 66 As at February 20, 2013, there were 572,936,551 Class B subordinate voting shares and 9,353,470 Class A common  shares outstanding. In addition, there were 8,893,876 employee stock options outstanding, with exercise prices ranging  between $4.15 and $58.80 per share. More information on these instruments and the terms of their conversion are  set out in the equity note to our 2012 consolidated financial statements. We do not expect the preceding changes to significantly affect our financial covenants or key ratios. The implementation  of the above IFRS pronouncements is not expected to significantly impact our information systems.  For all changes to policies and procedures that have been identified relating to the above items, the effectiveness of  internal controls over financial reporting and disclosure controls and procedures have been assessed and any changes  have been implemented. We have identified and implemented accounting process changes relating to the above new  policies and these changes were not significant. We applied our existing control framework to the implementation of  the new standards. All accounting policy changes and financial effects are subject to review by senior management  and the Audit Committee of the Board of Directors. We are in the process of calculating the impact of IFRIC 20 on our comparative consolidated financial statements for  all periods of 2012. We expect to capitalize significant stripping activity assets in 2012 under the requirements of  IFRIC 20. Stripping activity assets capitalized under IFRIC 20 will be classified consistently with the assets that they relate to  within property, plant and equipment. These assets will be amortized on a units-of-production basis over the  remaining reserves of the respective components. Based on our analysis to date, we have identified components of our orebodies to be phases, pits or sub-pits depending  on the orebody being analyzed. These components align with how we view each mine and plan our mining activities.  Previously, we recorded stripping activity assets only relating to major expansions. Under IFRIC 20, we will be required  to recognize stripping activity assets when we meet the following three criteria: We have substantially completed our analysis of IFRIC 20 and are in the process of calculating the effect on our  consolidated financial statements for the 2012 comparative periods. We will apply IFRIC 20 prospectively from  January 1, 2012. In October 2011, the IASB issued IFRIC 20, Stripping Costs in the Production Phase of a Surface Mine (IFRIC 20).  The interpretation provides guidance on how to account for overburden waste removal stripping costs in the production  phase of a surface mine. Stripping activity related to inventory produced is accounted for in accordance with IAS 2,  Inventories. Stripping activity that improves access to ore is accounted for as an addition to or enhancement of an  existing asset. • It is probable that the future economic benefit (improved access to the orebody) associated with the stripping  activity will flow to the entity; • The entity can identify the component of the orebody for which access has been improved; and • The costs relating to the stripping activity associated with that component can be measured reliably.