Equity Award Plans (Tables)

12 Months Ended

Dec. 31, 2011

Equity Award Plans

Summary of activity related to stock options during the year including awards applicable to discontinued operations

	Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value ($000)
Outstanding at December 31, 2010		514,708		$	28.54
Granted		80,432		$	116.78
Granted in exchange for Western Coal stock options		193,498		$	50.16
Exercised		(265,833	)	$	33.70
Cancelled		(27,481	)	$	126.04
Outstanding at December 31, 2011		495,324		$	43.13		5.5	$	12,259
Exercisable at December 31, 2011		381,507		$	34.02		4.6	$	10,623

Schedule of weighted average assumptions used to determine the grant-date fair value of options granted

	For the year ended December 31,
	2011(1)			2010			2009
Risk free interest rate		0.88	%		2.22	%		2.12	%
Dividend yield		0.52	%		0.75	%		0.75	%
Expected life (years)		2.46			5.10			5.24
Volatility		57.51	%		69.64	%		64.37	%

(1)

Includes fully vested replacement stock options issued on April 1, 2011 in connection with the acquisition of Western Coal described in Note 3, which significantly reduced the expected life as compared to prior periods.

Summary of activity related to restricted stock units during the year including awards applicable to discontinued operations

	Shares			Aggregate Intrinsic Value ($000)		Weighted Average Remaining Contractual Term in Years
Outstanding at December 31, 2010		201,838
Granted		144,517
Vested		(127,598	)
Cancelled		(55,510	)
Outstanding at December 31, 2011		163,247		$	9,886		1.47