SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2022

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Summary of intangible assets

	December 31, 2022						December 31, 2021
			Accumulated		Intangibles,				Accumulated		Intangibles,
	Original Cost		Amortization		Net		Original Cost		Amortization		Net
	(in thousands)
Customer contracts and other		10,623		(10,623)		—		10,623		(9,504)		1,119
Mining permits		1,500		(472)		1,028		1,500		(418)		1,082
Total	$	12,123	$	(11,095)	$	1,028	$	12,123	$	(9,922)	$	2,201

Schedule of estimated amortization expense attributable to intangible assets

Year Ended December 31,		(in thousands)
2023	$	54
2024		54
2025		54
2026		54
2027		54
Thereafter		758

Summary of advance royalties

	December 31,
	2022		2021
	(in thousands)
Advance royalties, affiliates (see Note 22 – Related-Party Transactions)	$	60,608	$	55,613
Advance royalties, third-parties		14,661		12,869
Total advance royalties	$	75,269	$	68,482