Revenues - Disaggregation of revenue (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) oz	Dec. 31, 2021 USD ($) oz
Disaggregation of Revenue [Line Items]
Revenues	$ 33,229	$ 110,734
Customer concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Percentage	100.00%	100.00%
Customer A
Disaggregation of Revenue [Line Items]
Revenues	$ 12,159	$ 10,610
Customer A | Customer concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Percentage	36.60%	9.60%
Customer B
Disaggregation of Revenue [Line Items]
Revenues	$ 10,997	$ 99,480
Customer B | Customer concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Percentage	33.10%	89.80%
Customer C
Disaggregation of Revenue [Line Items]
Revenues	$ 10,073	$ 0
Customer C | Customer concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Percentage	30.30%	0.00%
Customer D
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ 644
Customer D | Customer concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Percentage	0.00%	0.60%
Gold sales
Disaggregation of Revenue [Line Items]
Revenues	$ 32,249	$ 100,532
Ounces Sold | oz	17,728	56,045
Silver sales
Disaggregation of Revenue [Line Items]
Revenues	$ 980	$ 10,202
Ounces Sold | oz	44,084	397,546