v3.26.1
Provision for rehabilitation and closure costs - Reconciliation (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Reconciliation of changes in other provisions [abstract]    
Current portion $ 3,768 $ 6,766
Non-current portion 21,978 21,891
Revisions to rehabilitation and closure plans 600  
Provision for rehabilitation and closure costs    
Reconciliation of changes in other provisions [abstract]    
Balance, beginning of year 28,657 26,687
Change in estimates (4,303) 12,499
Accretion expense 3,517 2,339
Settled (5,608) (5,870)
Foreign exchange 3,483 (6,998)
Balance, end of year 25,746 28,657
Provision for rehabilitation and closure costs | MCSA Mining Complex    
Reconciliation of changes in other provisions [abstract]    
Balance, beginning of year 20,689  
Balance, end of year 15,743 20,689
Provision for rehabilitation and closure costs | NX Gold    
Reconciliation of changes in other provisions [abstract]    
Balance, beginning of year 3,868  
Balance, end of year 5,183 3,868
Provision for rehabilitation and closure costs | Xavantina    
Reconciliation of changes in other provisions [abstract]    
Balance, beginning of year 4,100  
Balance, end of year $ 4,820 $ 4,100