XML 107 R75.htm IDEA: XBRL DOCUMENT v3.8.0.1
Mineral Properties, Plant and Equipment - Rollforward of Carrying Value (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning $ 1,222,727 $ 1,145,221
Additions 148,102 200,837
Acquisition of Mining Properties 40,345  
Acquisition of mineral interests 8,650  
Disposals (2,905) (1,208)
Depreciation and amortisation expense (122,888) (115,955)
Depreciation charge captured in inventory (4,104) (9,675)
Reversals of impairment 61,554 0
Transfers to Assets Held for Sale (7,949)  
Transfers (2,580) (5,130)
Closure and decommissioning – changes in estimate 4,381 8,637
Carrying value, ending 1,336,683 1,222,727
Cost 3,639,050 3,469,673
Accumulated depreciation, amortisation and impairment [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning (2,246,946)  
Carrying value, ending (2,302,367) (2,246,946)
Other property, plant and equipment [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning 209,695 128,528
Additions 23,938 112,506
Acquisition of Mining Properties 30  
Disposals (2,710) (1,208)
Depreciation and amortisation expense (69,764) (81,152)
Depreciation charge captured in inventory 0 0
Reversals of impairment 25,814  
Transfers to Assets Held for Sale (2)  
Transfers 57,862 51,021
Closure and decommissioning – changes in estimate 0 0
Carrying value, ending 244,863 209,695
Cost 889,655 820,687
Other property, plant and equipment [member] | Accumulated depreciation, amortisation and impairment [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning (610,992)  
Carrying value, ending (644,792) (610,992)
Depletable, Reserves and Resources [member] | Mining property [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning 694,501 620,035
Additions 120,098 88,331
Acquisition of Mining Properties 0  
Disposals 0 0
Depreciation and amortisation expense (53,124) (34,803)
Depreciation charge captured in inventory (4,104) (9,675)
Reversals of impairment 27,531  
Transfers to Assets Held for Sale 0  
Transfers (22,400) 21,976
Closure and decommissioning – changes in estimate 4,381 8,637
Carrying value, ending 766,883 694,501
Cost 2,018,937 1,916,954
Depletable, Reserves and Resources [member] | Mining property [member] | Accumulated depreciation, amortisation and impairment [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning (1,222,453)  
Carrying value, ending (1,252,054) (1,222,453)
Non-depletable, Reserves and Resources [member] | Mining property [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning 58,578 120,351
Additions 4,066 0
Acquisition of Mining Properties 40,315  
Disposals 0 0
Depreciation and amortisation expense 0 0
Depreciation charge captured in inventory 0 0
Reversals of impairment 6,892  
Transfers to Assets Held for Sale 0  
Transfers (38,042) (61,773)
Closure and decommissioning – changes in estimate 0 0
Carrying value, ending 71,809 58,578
Cost 77,242 70,675
Non-depletable, Reserves and Resources [member] | Mining property [member] | Accumulated depreciation, amortisation and impairment [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning (12,097)  
Carrying value, ending (5,433) (12,097)
Non-depletable, Exploration and Evaluation [member] | Mining property [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning 259,953 276,307
Additions 0 0
Acquisition of Mining Properties 0  
Disposals (195) 0
Depreciation and amortisation expense 0 0
Depreciation charge captured in inventory 0 0
Reversals of impairment 1,317  
Transfers to Assets Held for Sale (7,947)  
Transfers 0 (16,354)
Closure and decommissioning – changes in estimate 0 0
Carrying value, ending 253,128 259,953
Cost 653,216 661,357
Non-depletable, Exploration and Evaluation [member] | Mining property [member] | Accumulated depreciation, amortisation and impairment [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning (401,404)  
Carrying value, ending $ (400,088) $ (401,404)