MINING INTERESTS (Tables)

12 Months Ended

Dec. 31, 2018

Property, plant and equipment [abstract]

Summary of the cost, accumulated depreciation and net book value of plant and equipment, mining properties and construction in progress

The following table shows the breakdown of the cost, accumulated depreciation and net book value of plant and equipment, mining properties and construction in progress:

	Plant and equipment			Mining properties		Construction in progress			Total
Cost
As of December 31, 2016	461,438			746,657		131,409			1,339,504
Additions	649			632		63,072			64,353
Transfers	24,269			48,122		(72,391		)	—
Capitalized interest	—			—		5,285			5,285
Change in rehabilitation provision estimate	—			3,022		—			3,022
Disposals and other	(7,142		)	—		(452		)	(7,594		)
Balance at December 31, 2017	$	479,214		$	798,433	$	126,923		$	1,404,570
Additions	95			677		45,485			46,257
Transfers	16,516			127,902		(144,418		)	—
Capitalized interest	—			—		579			579
Change in rehabilitation provision estimate	—			3,218		—			3,218
Disposals and other	(17,065		)	—		—			(17,065		)
Balance at December 31, 2018	$	478,760		$	930,230	$	28,569		$	1,437,559
Accumulated depreciation
As of December 31, 2016	431,698			692,789		—			1,124,487
Depreciation and amortization	12,385			20,431		—			32,816
Disposals and other	(6,791		)	—		—			(6,791		)
Balance at December 31, 2017	$	437,292		$	713,220	$	—		$	1,150,512
Depreciation and amortization	12,349			20,900		—			33,249
Disposals and other	(16,842		)	—		—			(16,842		)
Balance at December 31, 2018	$	432,799		$	734,120	$	—		$	1,166,919
Carrying amount
Balance at December 31, 2017	$	41,922		$	85,213	$	126,923		$	254,058
Balance at December 31, 2018	$	45,961		$	196,110	$	28,569		$	270,640