Asset Retirement Obligations (Tables)

9 Months Ended

Sep. 30, 2012

Asset Retirement Obligation Disclosure [Abstract]

Schedule of changes in the carrying amounts of the ARO

The changes in the carrying amount of the ARO during the nine months ended September 30, 2012, and September 30, 2011, are as follows:

	For the nine months ended
	September 30,
	2012			2011
Beginning balance	$	33,880		$	44,952
Accretion expense	2,111			5,300
Additions and changes in estimates	—			3,748
Cost of reclamation work performed	(5,389		)	(20,244		)
Balance at September 30	$	30,602		$	33,756
Current portion	$	7,886		$	11,445
Long term portion	$	22,716		$	22,311