v3.26.1
PROPERTY, PLANT AND EQUIPMENT - Depreciation and amortization (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
PROPERTY, PLANT AND EQUIPMENT        
Depreciation of plant and equipment $ 11,192 $ 10,893 $ 22,422 $ 21,258
Amortization of right of use assets (finance leases) 1,762 2,002 3,461 3,894
Amortization and depletion of capitalized mine development costs and mineral rights 3,857 4,143 7,541 9,428
Total depreciation, depletion, and amortization $ 16,811 $ 17,038 $ 33,424 $ 34,580