Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2017

Asset Retirement Obligation Disclosure

Schedule of changes in carrying amount of asset retirement obligations

		2017		2016
Balance as of January 1		$	98,166	$	153,155
Accretion			7,072		6,645
Revisions to estimated future reclamation cash flows			(3,802)		(60,681)
Payments			(1,126)		(953)
Balance as of December 31			100,310		98,166
Less: current portion			(1,013)		(1,118)
	Asset retirement obligation, net of current portion	$	99,297	$	97,048