Convertible debt - Schedule of Glencore Convertible Notes Valuation Assumptions (Details) - Glencore Convertible Notes	Dec. 31, 2023	Dec. 31, 2022	Oct. 31, 2022	May 31, 2022
Risk free interest rate
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	0.038	0.042	0.044	0.029
Expected life of options
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	3.4	4.4	4.6	5.0
Expected dividend yield
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	0.000	0.000	0.000	0.000
Expected stock price volatility
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	0.65	0.63	0.63	0.68
Share Price
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	0.58	4.76	5.96	8.15