SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2016

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Summary of intangible assets

	December 31, 2016						December 31, 2015
			Accumulated		Intangibles,				Accumulated		Intangibles,
	Original Cost		Amortization		Net		Original Cost		Amortization		Net
	(in thousands)
Non-compete agreements	$	14,542	$	(10,974)	$	3,568	$	14,729	$	(9,750)	$	4,979
Customer contracts and other, net		54,978		(33,300)		21,678		31,054		(16,959)		14,095
Mining permits		1,500		(104)		1,396		1,500		(28)		1,472
Total	$	71,020	$	(44,378)	$	26,642	$	47,283	$	(26,737)	$	20,546

Schedule of estimated amortization expense attributable to intangible assets

Year Ended December 31,		(in thousands)
2017	$	10,581
2018		6,830
2019		7,737
2020		391
2021		74
Thereafter		1,029

Summary of advance royalties

	2016		2015
	(in thousands)
Advance royalties, affiliates (see Note 18 – Related-Party Transactions)	$	19,820	$	16,190
Advance royalties, third-parties		10,759		11,925
Total advance royalties, net	$	30,579	$	28,115