Provisions Decommissioning and restoration provisions Environmental disturbance restoration provisions Other provisions Share Repurchases Research and Development Earnings per Share Future obligations to retire an asset and to restore a site, including dismantling, remediation and ongoing treatment  and monitoring of the site related to normal operations are initially recognized and recorded as a provision based  on estimated future cash flows discounted at a credit adjusted risk-free rate. This decommissioning and restoration  provision is adjusted at each reporting period for changes to factors including the expected amount of cash flows  required to discharge the liability, the timing of such cash flows and the discount rate. The provisions are also accreted to full value over time through periodic charges to profit. This unwinding of the  discount is charged to finance expense in the statement of income. The amount of the decommissioning and restoration provision initially recognized is capitalized as part of the related  asset’s carrying value and depreciated to profit. The method of depreciation follows that of the underlying asset.  The costs related to a decommissioning and restoration provision are only capitalized to the extent that the amount  meets the definition of an asset and can bring about future economic benefit. For a closed site or where the asset  which generated a decommissioning and restoration provision no longer exists, there is no longer any future benefit  related to the costs and, as such, the amounts are expensed. For operating sites, a revision in estimates or a new  disturbance will result in an adjustment to the liability with an offsetting adjustment to the capitalized retirement cost. During the operating life of an asset, events such as infractions of environmental laws or regulations may occur.  These events are not related to the normal operation of the asset. The costs associated with these provisions are  accrued and charged to profit in the period in which the event giving rise to the liability occurs. Any subsequent  adjustments to these provisions due to changes in estimates are also charged to profit in the period of adjustment. Provisions are recognized when a present legal or constructive obligation exists, as a result of past events, and it is  probable that an outflow of resources that can be reliably estimated will be required to settle the obligation. Where  the effect is material, the provision is discounted using an appropriate credit-adjusted risk-free rate. Where we repurchase any of our equity share capital, the excess of the consideration paid over book value is  deducted from contributed surplus and retained earnings on a pro-rata basis. Research costs are expensed as incurred. Development costs are only deferred when the product or process is clearly  defined, the technical feasibility has been established, the future market for the product or process is clearly defined  and we are committed to, and have the resources to, complete the project. Earnings per share is calculated based on the weighted average number of shares outstanding during the year. For diluted  earnings per share, dilution is calculated based upon the net number of common shares issued should “in-the-money”  options and warrants be exercised and the proceeds used to repurchase common shares at the average market price  in the year. Dilution from convertible securities is calculated based on the number of shares to be issued after taking  into account the reduction of the related after-tax interest expense. Generations 89