Condensed Consolidated Statements of Financial Position (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 3,114	$ 8,796
Restricted cash	3,652	7,116
Accounts receivable, net of allowance for doubtful accounts ($-0- as of June 30, 2018 and December 31, 2017)	15,333	20,386
Inventories	15,862	12,860
Advance royalties, current portion	819	495
Investment in available for sale securities	3,535	11,165
Prepaid expenses and other	3,898	2,891
Total current assets	46,213	63,709
PROPERTY, PLANT AND EQUIPMENT:
At cost, including coal properties, mine development and construction costs	448,799	440,843
Less accumulated depreciation, depletion and amortization	(270,137)	(263,520)
Net property, plant and equipment	178,662	177,323
Advance royalties, net of current portion	7,935	7,901
Deposit - Workers' Compensation Program	5,209
Investment in unconsolidated affiliates		130
Restricted cash		5,209
Other non-current assets	28,981	28,508
TOTAL	267,000	282,780
CURRENT LIABILITIES:
Accounts payable	14,116	9,329
Accrued expenses and other	12,533	11,186
Accrued preferred distributions	609	6,038
Current portion of long-term debt	2,320	5,475
Current portion of asset retirement obligations	498	498
Total current liabilities	30,076	32,526
NON-CURRENT LIABILITIES:
Long-term debt, net of current portion	23,097	28,573
Asset retirement obligations, net of current portion	18,645	18,164
Other non-current liabilities	48,212	48,071
Total non-current liabilities	89,954	94,808
Total liabilities	120,030	127,334
COMMITMENTS AND CONTINGENCIES (NOTE 13)
PARTNERS' CAPITAL:
Limited partners	124,024	130,233
General partner	8,828	8,855
Preferred partners	15,000	15,000
Investment in Royal common stock (NOTE 11)	(4,126)	(4,126)
Common unit warrants	1,264	1,264
Accumulated other comprehensive income	1,980	4,220
Total partners' capital	146,970	155,446
TOTAL	$ 267,000	$ 282,780