Plant, Equipment, and Mine Development, Net (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2021

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Components of plant, equipment, and mine development, net

The following table provides the components of Plant, equipment, and mine development, net (dollars in thousands):

	Depreciation Life or Method	March 31, 2021		December 31, 2020
Leach pads	Units-of-production	$	17,432	$	17,432
Process equipment	5 - 15 years	17,459		16,065
Buildings and leasehold improvements	10 years	10,507		10,507
Mine equipment	5 - 7 years	6,707		5,961
Vehicles	3 - 5 years	1,227		991
Furniture and office equipment	7 years	341		322
Mine development	Units-of-production	1,096		756
Mineral properties	Units-of-production	37		37
Construction in progress and other		37,683		33,185
		$	92,489	$	85,256
Less, accumulated depreciation and amortization		(26,134)		(25,033)
Total		$	66,355	$	60,223

The following table provides the components of plant, equipment, and mine development, net (in thousands):

	Depreciation Life or Method	December 31, 2020		December 31, 2019
Leach pads	Units-of-production	$	17,432	$	17,419
Process equipment	5 - 15 years	16,065		14,770
Buildings and leasehold improvements	10 years	10,507		10,507
Mine equipment	5 - 7 years	5,961		4,716
Vehicles	3 - 5 years	991		136
Furniture and office equipment	7 years	322		129
Mine development	Units-of-production	756		119
Mineral properties	Units-of-production	37		—
Construction in progress and other		33,185		936
		$	85,256	$	48,732
Less, accumulated depreciation and amortization		(25,033)		(17,208)
Total		$	60,223	$	31,524