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Asset Retirement Obligations

6 Months Ended

Jun. 30, 2015

Asset Retirement Obligation Disclosure

10. Asset Retirement Obligations

Changes in the carrying amount of our asset retirement obligations were as follows (in thousands):

	2015		2014
Balance at January 1,	$	217,312	$	247,329
Accretion expense		6,890		8,217
Revisions to estimated future reclamation cash flows		(22,410)		(3,409)
Payments		(546)		(561)
Balance at June 30,		201,246		251,576
Less: current portion		(1,071)		(1,118)
Asset retirement obligation, net of current portion	$	200,175	$	250,458

Revisions to estimated future reclamation cash flows reflect our regular updates to our estimated costs of closure activities throughout the lives of the respective mines and reflect changes in estimates of closure volumes, disturbed acreages, the timing of the reclamation activities, and third-party unit costs as of June 30, 2015 and 2014.