Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 197,157	$ 109,097
Investments, at fair market value	57,953	49,533
Inventories	121,578	131,856
Trade receivables	8,568	6,188
Deferred income taxes	109,629	96,036
Other current assets	12,473	9,433
Total current assets	507,358	402,143
Mineral properties	597,187	596,686
Property, plant and equipment, net of $465,847 and $436,612 of accumulated depletion, depreciation and amortization	394,923	367,727
Restricted cash	24,995	25,070
Other noncurrent assets	11,444	11,915
Total assets	1,535,907	1,403,541
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	24,582	26,880
Accrued compensation and benefits	28,846	27,573
Property, production and franchise taxes payable	14,853	14,071
Current portion of long-term debt and capital lease obligations	168,228	0
Income taxes payable	0	1,235
Other current liabilities	1,811	4,576
Total current liabilities	238,320	74,335
Long-term debt	34,849	196,046
Deferred income taxes	277,085	270,101
Accrued workers compensation	6,558	6,056
Asset retirement obligation	7,641	7,331
Other noncurrent liabilities	5,318	5,704
Total liabilities	569,771	559,573
Stockholders' equity
Preferred stock, $0.01 par value, 1,000,000 shares authorized; none issued	0	0
Common stock, $0.01 par value, 200,000,000 shares authorized; 115,907,989 and 115,375,604 shares issued and outstanding	1,159	1,154
Paid-in capital	927,356	878,050
Accumulated deficit	(13,636)	(34,275)
Accumulated other comprehensive loss	(762)	(961)
Total stockholders' equity	914,117	843,968
Noncontrolling interest	52,019	0
Total equity	966,136	843,968
Total liabilities and stockholders' equity	$ 1,535,907	$ 1,403,541