ASSET RETIREMENT OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2022

ASSET RETIREMENT OBLIGATIONS

Schedule of activity affecting the asset retirement and mine closing liability

	Year Ended December 31,
	2022		2021
	(in thousands)
Beginning balance	$	131,099	$	127,898
Accretion expense		3,731		3,688
Payments		(2,445)		(1,383)
Allocation of liability associated with mine development and change in assumptions		17,428		896
Ending balance	$	149,813	$	131,099

Schedule of estimated payments of asset retirement obligations

Year Ended
December 31,	(in thousands)
2023	$	7,559
2024		4,936
2025		1,935
2026		1,569
2027		3,182
Thereafter		241,065
Aggregate undiscounted asset retirement obligations		260,246
Effect of discounting		(110,433)
Total asset retirement obligations		149,813
Less: current portion		(7,559)
Non-current asset retirement obligations	$	142,254