Property, Plant and Equipment	3 Months Ended
Property, Plant and Equipment	Mar. 31, 2026
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	7. Property, Plant and Equipment (in US$ thousands) March 31, 2026 December 31, 2025 Land $ 29,301 $ 29,008 Buildings and improvements 141,699 138,771 Plant, machinery, mining equipment and transportation vehicles 1,543,353 1,516,095 Mineral rights and reserves 370,393 370,393 Office and computer equipment 20,442 20,063 Mine development 708,119 694,779 Asset retirement obligation asset 80,502 79,094 Construction in process 105,754 103,011 Total cost of property, plant and equipment 2,999,563 2,951,214 Less accumulated depreciation, depletion, amortization and impairment 1,508,186 1,296,759 Property, plant and equipment, net $ 1,491,377 $ 1,654,455