SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2015

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Summary of intangible assets

	December 31, 2015						December 31, 2014
	Original Cost		Accumulated Amortization		Intangibles, Net		Original Cost		Accumulated Amortization		Intangibles, Net
					(in thousands)
Non-compete agreements	$	14,729	$	(9,750)	$	4,979	$	15,152	$	(8,545)	$	6,607
Customer contracts and other	31,054		(16,959)		14,095		17,859		(3,599)		14,260
Mining permits	1,500		(28)		1,472		3,843		(182)		3,661
Total	$	47,283	$	(26,737)	$	20,546	$	36,854	$	(12,326)	$	24,528

Schedule of estimated amortization expense attributable to intangible assets

Year Ending December 31,	(in thousands)
2016	$	15,300
2017	1,682
2018	1,021
2019	1,021
2020	385
Thereafter	1,137

Summary of advance royalties

	2015		2014
	(in thousands)
Advance royalties, affiliates (see Note 19 – Related-Party Transactions)	$	16,245	$	10,706
Advance royalties, third-parties	11,870		14,605
Total advance royalties, net	$	28,115	$	25,311