Notes t o the Financial Statements continued u Notes to the Financial Statements 71 which the Group becomes a party to the  contractual provisions of the instrument. losses, are recognised as a separate component  of equity net of attributable tax. When an asset  is derecognised the cumulative gain or loss in  equity is transferred to the statement of  comprehensive income. The Group derecognises a financial asset when  the contractual rights to the cash flows from the  asset expire, or it transfers the rights to receive  the contractual cash flows on the financial asset  in a transaction in which substantially all the  risks and rewards of ownership of the financial  assets are transferred. Financial assets and liabilities are offset and the  net amount presented in the statement of  financial position when, and only when, the  Group has a legal right to offset the amounts  and intends either to settle on a net basis or to  realise the asset and settle the liability  simultaneously. The Group assesses at each reporting date  whether there is objective evidence that a  financial asset or group of financial assets is  impaired. In the case of equity securities classi- fied as available-for-sale, a significant or  prolonged decline in the fair value of a security  below its cost is considered as an indicator that  the securities are impaired. If any such evidence  exists for available-for-sale financial assets, the  cumulative loss measured as the difference  between the acquisition cost and the current  fair value, less any impairment loss on that  financial asset previously recognised in profit or  loss, is removed from equity and recognised in  the statement of comprehensive income.  Impairment losses recognised in the profit or  loss on equity instruments classified as avail- able-for-sale are not reversed through the state- ment of comprehensive income. Attributable transaction costs are recognised in  the profit or loss when incurred. Assets in this  category are classified as current assets if they  are expected to be settled within 12 months,  otherwise they are classified as non-current. Financial assets at fair value through profit or loss  are financial assets held for trading if acquired  principally for the purpose of selling in the short  term. Derivatives are also categorised as held for  trading unless they are designated as hedges.  Loans and receivables are non-derivative finan- cial assets with fixed or determinable payments  that are not quoted in an active market. They  are included in current assets, except for those  with maturities greater than 12 months after  the reporting date which are classified as non- current assets. Loans and receivables are measured at amor- tised cost using the effective interest method,  less any impairment losses. Available-for-sale financial assets, comprising  principally marketable equity securities, are  non-derivative financial assets that are either  designated in this category or not classified in  any of the other categories. They are included in  non-current assets unless management intends  to dispose of the investment within 12 months  of the reporting date. Investments are desig- nated as available-for-sale if they do not have  fixed maturities and fixed or determinable  payments and management intends to hold  them for the medium to long term. Subsequent to initial recognition, available-for- sale financial assets are measured at fair value  and changes therein, other than impairment  Property, plant and equipment are stated at  historical cost less depreciation. Historical cost  includes expenditure that is directly attributable  to the acquisition of the items.  Subsequent costs are included in the asset’s  carrying amount or recognised as a separate  Any gain or loss arising on derecognition of the  asset (calculated as the difference between the  net disposal proceeds and the carrying amount  of the item) is included in the profit or loss in the  period the item is derecognised.  An item of property, plant and equipment is  derecognised upon disposal or when no future  economic benefits are expected to arise from  the continued use of the asset. Derivative financial instruments are stated at  fair value on the date a derivative contract is  entered into and are subsequently remeasured  to their fair value at each reporting date. The  resulting gain or loss is recognised in the state- ment of comprehensive income immediately. An asset’s carrying amount is written down  immediately to its recoverable amount if the  asset’s carrying amount is greater than its  estimated recoverable amount (Note 2f). Major spares purchased specifically for a partic- ular plant are capitalised and depreciated on the  same basis as the plant to which they relate.  Derivative financial instruments are used by the  Group to protect against the Group’s Australian  dollar gold price risk exposures. The Group does  not apply hedge accounting and accordingly all  fair value movements on derivative financial  instruments are recognised in the profit or loss. The estimated recoverable reserves and life of  each mine and the remaining useful life of each  class of asset are reassessed at least annually.  Where there is a change in the reserves during  the period, depreciation and amortisation rates  are adjusted prospectively from the beginning of  the reporting period. If there is evidence of impairment for any of the  Group’s financial assets carried at amortised  cost, the loss is measured as the difference  between the asset’s carrying amount and the  present value of estimated future cash flows,  excluding future credit losses that have not been  incurred. The cash flows are discounted at the  financial asset’s original effective interest rate.  The loss is recognised in the statement of  comprehensive income. The expected useful lives are as follows: Depreciation and amortisation is determined on  a units-of-production basis over the estimated  recoverable reserves from the related area. In  some circumstances, where conversion of  resources into reserves is expected, some  elements of resources may be included. For mine  plant, machinery and equipment, which have an  expected economic life shorter than the life of  the mine, a straight line basis is adopted. Depreciation and amortisation of mine build- ings, plant, machinery and equipment is  provided over the assessed life of the relevant  mine or asset, whichever is the shorter. asset, as appropriate, only when it is probable  that future economic benefits associated with  the item will flow to the Group and the cost of  the item can be measured reliably. The carrying  amount of any component accounted for as a  separate asset is derecognised when replaced.  All other repairs and maintenance are charged to  the statement of comprehensive income during  the reporting period in which they are incurred. Depreciation Impairment k .  Derivative financial instruments l .  Property, plant and equipment Derecognition Impairment 〉 plant, machinery and equipment – the  shorter of applicable mine life and 3–15  years depending on the nature of the asset. 〉 mine buildings – the shorter of applicable  mine life and 25 years; (ii)  Loans and receivables (iii)  Available-for-sale financial assets (i)   Financial assets at fair value through profit or loss