XML 109 R78.htm IDEA: XBRL DOCUMENT v3.19.1
Mineral Properties, Plant and Equipment - Rollforward of Carrying Value (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning $ 1,336,683 $ 1,222,727
Additions 149,020 148,102
Acquisition of mineral interests   40,345
Disposals (1,333) (2,905)
Depreciation and amortisation expense (147,289) (122,888)
Depreciation charge captured in inventory (12,620) (4,104)
(Impairment charges) reversals (27,789)  
Reversals of impairment 27,789 (61,554)
Transfers to Assets Held for Sale   (7,949)
Transfers 0 (2,580)
Closure and decommissioning – changes in estimate 4,330 4,381
Carrying value, ending 1,301,002 1,336,683
Cost 3,710,845 3,639,050
Accumulated depreciation, amortisation and impairment [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning (2,302,367)  
Carrying value, ending (2,409,843) (2,302,367)
Other property, plant and equipment [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning 244,863 209,695
Additions 16,896 23,938
Acquisition of mineral interests   30
Disposals (937) (2,710)
Depreciation and amortisation expense (78,354) (69,764)
Depreciation charge captured in inventory 0 0
(Impairment charges) reversals (532)  
Reversals of impairment   (25,814)
Transfers to Assets Held for Sale   (2)
Transfers 117,971 57,862
Closure and decommissioning – changes in estimate 0 0
Carrying value, ending 299,907 244,863
Cost 939,993 889,655
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 (644,792)  
Carrying value, ending (640,086) (644,792)
Depletable, Reserves and Resources [member] | Mining property [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning 766,883 694,501
Additions 106,701 120,098
Acquisition of mineral interests   0
Disposals 0 0
Depreciation and amortisation expense (68,935) (53,124)
Depreciation charge captured in inventory (12,620) (4,104)
(Impairment charges) reversals (2,144)  
Reversals of impairment   (27,531)
Transfers to Assets Held for Sale   0
Transfers (115,726) (22,400)
Closure and decommissioning – changes in estimate 4,330 4,381
Carrying value, ending 678,489 766,883
Cost 1,997,880 2,018,937
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 (1,252,054)  
Carrying value, ending (1,319,391) (1,252,054)
Non-depletable, Reserves and Resources [member] | Mining property [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning 71,809 58,578
Additions 25,423 4,066
Acquisition of mineral interests   40,315
Disposals (396) 0
Depreciation and amortisation expense 0 0
Depreciation charge captured in inventory 0 0
(Impairment charges) reversals (25,113)  
Reversals of impairment   (6,892)
Transfers to Assets Held for Sale   0
Transfers 1,652 (38,042)
Closure and decommissioning – changes in estimate 0 0
Carrying value, ending 73,375 71,809
Cost 104,614 77,242
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 (5,433)  
Carrying value, ending (31,239) (5,433)
Non-depletable, Exploration and Evaluation [member] | Mining property [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Carrying value, beginning 253,128 259,953
Additions 0 0
Acquisition of mineral interests   0
Disposals 0 (195)
Depreciation and amortisation expense 0 0
Depreciation charge captured in inventory 0 0
(Impairment charges) reversals 0  
Reversals of impairment   (1,317)
Transfers to Assets Held for Sale   (7,947)
Transfers (3,897) 0
Closure and decommissioning – changes in estimate 0 0
Carrying value, ending 249,231 253,128
Cost 668,358 653,216
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 (400,088)  
Carrying value, ending $ (419,127) $ (400,088)