92 Impairment loss Depreciation and amortisation expense Depreciation and amortisation expense of $15.8 million (2011: $17.0 million) is included in the line item ‘depreciation and amortisation’ in  the income statement. At 30 June 2012, the consolidated entity reviewed the carrying amount of its exploration and evaluation assets for indicators of impairment  in accordance with the consolidated entity’s accounting policy (refer note 1 (p)). As a result, the recoverable amounts of some specific  exploration and evaluation assets were formally reassessed. Estimates of recoverable amounts of exploration and evaluation assets are  based on the assets’ fair value less costs to sell. The review resulted in the recognition of an impairment loss of $21.8 million in relation to the consolidated entity’s 40% interest in the  exploration permit ATP 1056P, located in the Cooper Basin in south-west Queensland.  An impairment loss of $14.0 million was also recognised in relation to the consolidated entity’s geothermal exploration assets located in  Victoria, Queensland and New South Wales.  The impairment loss of $35.8 million (2011: $nil) is included in other expenses in the line item ‘impairment loss on exploration and evaluation  assets’ in Note 7. The impairment loss of $35.8 million has been recognised in the Upsteam Gas operating segment. 2012  $m 2011  $m Note 19 – Exploration and evaluation assets Balance at beginning of financial year 658.0  607.5  Additions 38.3  30.7  Acquisitions through business combinations (Note 43) –  19.8  Impairment loss (35.8) –  Disposals (6.5) –  Balance at end of financial year 654.0  658.0 2012  $m 2011  $m Note 20 – Oil and gas assets Producing assets Balance at beginning of financial year 461.4  333.4  Additions 66.0  55.0  Acquisitions through business combinations (Note 43) –  104.5  Fair value adjustments on prior year acquisitions (20.0) –  Transferred to property, plant and equipment (Note 21) –  (14.5) Disposals (7.8) –  Depreciation and amortisation expense (15.8) (17.0) Balance at end of financial year 483.8  461.4  Cost (gross carrying amount) 574.1  536.0  Accumulated depreciation, amortisation and impairment (90.3) (74.6) Net carrying amount 483.8  461.4 Consolidated  Notes to the  Financial  Statements