ACCRUED WORKERS' COMPENSATION AND PNEUMOCONIOSIS BENEFITS (Tables)

12 Months Ended

Dec. 31, 2012

Accrued Workers Compensation And Pneumoconiosis Benefits

Components of Black Lung and Workers Compensation Expense

        The black lung and workers' compensation expense consists of the following components for the year ended December 31, 2012, 2011 and 2010 (in thousands):

	2012		2011			2010
Black lung benefits:
Service cost	$	3,758	$	3,345		$	2,359
Interest cost		2,372		2,382			1,857
Net amortization		776		(223	)		(176	)
Total black lung		6,906		5,504			4,040
Workers' compensation expense		17,572		18,996			16,776
Total expense	$	24,478	$	24,500		$	20,816

Reconciliation of Changes in Workers Compensation Liability

        The following is a reconciliation of the changes in workers' compensation liability (including current and long-term liability balances) at December 31, 2012 and 2011 (in thousands):

	2012			2011
Beginning balance	$	73,201		$	67,687
Accruals		24,812			22,254
Payments		(10,477	)		(11,235	)
Interest accretion		2,739			3,174
Valuation gain		(13,229	)		(8,679	)
Ending balance	$	77,046		$	73,201

Summary of Amounts Recognized in Balance Sheets for Black Lung and Workers Compensation Benefits

        Summarized below is information about the amounts recognized in the accompanying consolidated balance sheets for black lung and workers' compensation benefits at December 31, 2012 and 2011 (in thousands):

	2012			2011
Black lung claims	$	60,991		$	55,605
Workers' compensation claims		77,046			73,201
Total obligations		138,037			128,806
Less current portion		(9,320	)		(9,511	)
Non-current obligations	$	128,717		$	119,295

Black Lung

Accrued Workers Compensation And Pneumoconiosis Benefits

Components of Black Lung Benefit Obligation Recognized in Accumulated Other Comprehensive Income

        The following is a reconciliation of the changes in the black lung benefit obligation recognized in accumulated other comprehensive income for the years ended December 31, 2012 and 2011 (in thousands);

	2012		2011
Net actuarial gain (loss)	$	2,156	$	(4,570	)
Reversal of amortization item:
Net actuarial (gain) loss		776		(223	)
Total recognized in accumulated other comprehensive income (loss)	$	2,932	$	(4,793	)

Reconciliation of Changes in Black Lung Benefit Obligation

       The following is a reconciliation of the changes in black lung benefit obligations at December 31, 2012 and 2011 (in thousands):

	2012			2011
Benefit obligations at beginning of year	$	55,605		$	45,666
Service cost		3,758			3,345
Interest cost		2,372			2,382
Actuarial (gain) loss		(2,156	)		4,570
Benefits and expenses paid		(715	)		(358	)
Acquisition of Onton (Note 4)		2,127			—
Benefit obligations at end of year	$	60,991		$	55,605
Amount recognized in accumulated other comprehensive income consist of:
Net actuarial loss	$	8,908		$	11,840