Notes to the Financial Statements 76 www.kingsgate.com.au (iv) Impairment of assets (v) Restoration and rehabilitation provision (vi) Units-of-production method of depreciation (x) Capitalisation of borrowing costs to exploration, evaluation and  development  (ix) Income taxes (viii) Deferred tax balances (vii) Share-based payments 4. Segment information The Group’s operating segments are based on  the internal management reports that are  reviewed and used by the Board of Directors  (chief operating decision maker). The operating  segments represent the Group’s operating  mines and projects and include the following: Information regarding the results of each reportable segment is included as follows: 〉 Chatree Mine, Thailand; 〉 Challenger Mine, South Australia, Australia; 〉 Bowdens Silver Project, New South Wales,  Australia; 〉 Nueva Esperanza Silver / Gold Project, Chile;  and 〉 Exploration, South East Asia. The Group’s funding of Bowdens Silver Project  included borrowings of $35,000,000. In applying  the Group’s accounting policy on borrowing  costs (see Note 2s), the Bowdens Silver Project  is considered to be a qualifying asset as defined  in AASB 123. As such finance costs in relation to  these borrowings have been capitalised as part  of the Bowdens Silver Project. The Group is subject to income taxes in Australia  and jurisdictions where it has foreign operations.  Significant judgement is required in determining  the worldwide provision for income taxes. There  are certain transactions and calculations under- taken during the ordinary course of business for  which the ultimate tax determination is uncer- tain. The Group estimates its tax liabilities based  on the Group understanding of the tax law.  Where the final tax outcome of these matters is  different from the amounts that were initially  recorded, such differences will impact the  current and deferred income tax assets and  liabilities in the period in which such determina- tion is made. Deferred tax balances for temporary differences  in respect of Akara Mining Limited are measured  based on their expected rate of reversal which is  different for the two Royal Thai Board of  Investment (“BOI”) activities (Note 6). Deferred tax assets in respect of tax losses for  the Kingsgate tax-consolidation group (Note 6)  are not recognised in the financial statements as  management considers that it is currently not  probable that future taxable profits will be  available to utilise those tax losses. Management  reviews on a regular basis the future profitability  of the entities included in the tax-consolidation  group to consider if tax losses should be recog- nised and to ensure that any tax losses recog- nised will be utilised.  The Group assesses each cash-generating unit  half-yearly, to determine whether there is any  indication of impairment. Where an indicator of  impairment exists, a formal estimate of the  recoverable amount is made, which is deemed as  being the higher of the fair value less costs to  sell and value in use calculated in accordance  with accounting policy Note 2f. These assump- tions require the use of estimates and assump- tions such as discount rates, exchange rates,  commodity prices, future operating develop- ment and sustaining capital requirements,  mineral resources and reserves and operating  performance (including the magnitude and time  of related cash flows). For details of impairment  assessment for the current year, refer to Note 5j. Significant judgement is required in determining  the restoration and rehabilitation provision as  there are many transactions and factors that will  affect the ultimate liability payable to rehabilitate  the mine site. Factors that will affect this liability  include change in mineral resources and reserves  estimates, changes in technology, commodity  price changes and changes in interest rates.  A change in any, or a combination of, the key  assumptions used to determine the provisions  could have a material impact on the carrying  value of the provisions (see Note 17). The provi- sion recognised for each site is reviewed at each  reporting date and updated based on the facts  and circumstances available at the time. Changes  to the estimated future costs for operating sites  are recognised in the statement of financial  position by adjusting both the restoration and  rehabilitation asset and provision. The Group applies the units-of-production  method for depreciation and amortisation of its mine properties, mine buildings, plant and  equipment. These calculations require the use of estimates and assumptions and significant  judgement is required in assessing the estimated  recoverable reserves used in the determination  of the depreciation and amortisation charges.  Factors that must be considered in determining  estimated recoverable reserves (which includes  both reserves and resources) and production  capacity are the history of converting resources  to reserves and the relevant time frames, antici- pated mining method and costs, the complexity  of metallurgy, markets, and future  developments.  The Group measures share-based payments at fair value at the grant date. The fair value is  determined by an external valuer using a Monte  Carlo simulation model or other valuation tech- nique appropriate for the instrument being  valued.