Condensed Consolidated Statements Of Financial Position (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
CURRENT ASSETS:
Cash and cash equivalents	$ 438	$ 461
Accounts receivable, net of allowance for doubtful accounts ($0 as of June 30, 2013 and December 31, 2012)	24,693	33,560
Inventories	16,230	18,743
Advance royalties, current portion	74	187
Prepaid expenses and other	5,720	4,323
Total current assets	47,155	57,274
PROPERTY, PLANT AND EQUIPMENT:
At cost, including coal properties, mine development and construction costs	694,027	683,669
Less accumulated depreciation, depletion and amortization	(234,990)	(219,709)
Net property, plant and equipment	459,037	463,960
Advance royalties, net of current portion	5,377	4,506
Investment in unconsolidated affiliates	21,013	23,659
Intangible assets, net	1,187	1,228
Other non-current assets	8,985	8,831
TOTAL	542,754	559,458
CURRENT LIABILITIES:
Accounts payable	18,706	18,030
Accrued expenses and other	19,764	22,178
Current portion of long-term debt	1,041	2,350
Current portion of asset retirement obligations	1,818	2,255
Current portion of postretirement benefits	227	227
Total current liabilities	41,556	45,040
NON-CURRENT LIABILITIES:
Long-term debt, net of current portion	154,333	161,199
Asset retirement obligations, net of current portion	31,895	30,748
Other non-current liabilities	10,916	10,309
Postretirement benefits, net of current portion	6,726	6,520
Total non-current liabilities	203,870	208,776
Total liabilities	245,426	253,816
COMMITMENTS AND CONTINGENCIES (NOTE 13)
PARTNERS' CAPITAL:
Limited partners	284,933	292,791
General partner	11,037	11,420
Accumulated other comprehensive income	1,358	1,431
Total partners' capital	297,328	305,642
TOTAL	$ 542,754	$ 559,458