Note 3 - Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment.

Schedule of property, plant, and equipment

	December 31,
(In thousands)	2023		2022
Plant and equipment	$	290,060	$	232,885
Mining property and mineral rights		120,532		120,760
Construction in process		13,984		34,698
Capitalized mine development costs		174,260		153,436
Less: accumulated depreciation, depletion, and amortization		(139,745)		(111,937)
Total property, plant, and equipment, net	$	459,091	$	429,842

Schedule of depreciation and amortization

	Year ended December 31,
(In thousands)	2023		2022		2021
Depreciation of plant and equipment	$	30,913	$	24,132	$	17,945
Amortization of right-of-use assets (finance leases)		8,547		4,846		1,109
Amortization and depletion of capitalized
mine development costs and mineral rights		14,792		12,216		7,151
Total depreciation, depletion, and amortization	$	54,252	$	41,194	$	26,205