Note 3 - Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment.

Schedule of property, plant, and equipment

	December 31,
(In thousands)	2022		2021
Plant and equipment	$	232,885	$	167,019
Mining property and mineral rights		120,760		26,064
Construction in process		34,698		9,972
Capitalized mine development costs		153,436		104,291
Less: accumulated depreciation and amortization		(111,937)		(80,269)
Total property, plant and equipment, net	$	429,842	$	227,077

Schedule of depreciation and amortization

	Year ended December 31,
(In thousands)	2022		2021		2020
Depreciation of plant and equipment	$	24,132	$	17,945	$	17,094
Amortization of right of use assets (finance leases)		4,846		1,109		—
Amortization and depletion of
capitalized mine development costs and mineral rights		12,216		7,151		3,818
Total depreciation, depletion, and amortization	$	41,194	$	26,205	$	20,912