Finance costs and finance income - Unobservable valuation inputs (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Finance costs and finance income | ||
| Annual average of future sales of mineral | $ 400,476 | $ 275,865 |
| Useful life of mining properties | 15 years | 14 years |
| Pre-tax Discount rate (%) | 12.41% | 12.73% |