Notes to the Financial Statements 87 Notes t o the Financial Statements 13. Exploration, evaluation and development Exploration &  evaluation  $’000 Feasibility  expenditure  $’000 Mine properties  $’000 Total  $’000 At 30 June 2011 Cost  57,510 29,388 392,107 479,005 Accumulated depreciation and amortisation – – (71,912) (71,912) Net book amount  57,510 29,388 320,195 407,093 Year ended 30 June 2012 Opening net book amount  57,510 29,388 320,195 4 07,0 9 3 Additions   10,068  97,720 60,213 168,001 Reclassified  (8,350) (4,345) 34,223 21,528 Disposals  (2,009)  (952) (690) (3,651) Depreciation and amortisation expense – – (50,353) (50,353) Foreign currency exchange differences  293  (254) 2,375 2,414 Closing net book amount 57,512 121,557 365,963 545,032 Year ended 30 June 2013 Opening net book amount 57,512 121,557 365,963 545,032 Additions  7,9 3 8 19,234 98,276 125,448 Reclassified – – 2,039 2,039 Disposals (20,084) (1,023) (6,949) (28,056) Impairment (27,526) – (239,848) (267,374) Depreciation and amortisation expense – – (67,37 7 ) (67,37 7 ) Foreign currency exchange differences 1,242 3,173 22,419 26,834 Closing net book amount 19,082 142,941 174,523 336,546 At 30 June 2013 Cost 19,082 142,941 615,098 777,121 Accumulated depreciation and amortisation – – (440,575) (440,575) Net book amount 19,082 142,941 174,523 336,546 Capitalised borrowing costs Included in mine buildings, plant and equipment is an amount of $851,000 and in exploration is an amount of $4,112,000 that represents borrowing costs capitalised during  the year ($6,939,000 during the year ended 30 June 2012). The capitalisation rate used to determine the amount of borrowing costs to be capitalised is the weighted average  interest rate applicable to the entity’s outstanding borrowings during the year, in this case 10.7% (2012: 9.7%). continued u