ASSET RETIREMENT OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2012

ASSET RETIREMENT OBLIGATIONS

Schedule of Estimated Payments of Assets Retirement Obligations

Estimated payments of asset retirement obligations as of December 31, 2012 are as follows (in thousands):

Year Ending December 31,
2013	$	3,192
2014		2,168
2015		1,987
2016		23,762
2017		1,107
Thereafter		123,360
Aggregate undiscounted asset retirement obligations		155,576
Effect of discounting		(70,740	)
Total asset retirement obligations		84,836
Less: current portion		(3,192	)
Asset retirement obligations	$	81,644

Schedule of Activity in Asset Retirement and Mine Closing Liability

        The following table presents the activity affecting the asset retirement and mine closing liability (in thousands):

	Year ended December 31,
	2012			2011
Beginning balance	$	72,342		$	58,227
Accretion expense		2,853			2,546
Payments		(2,842	)		(1,920	)
Allocation of liability associated with acquisition, mine development and change in assumptions		12,483			13,489
Ending balance	$	84,836		$	72,342