The Toronto-headquartered company now expects production of 380,000–440,000 tonnes copper this year, down from earlier estimates of 400,000–450,000 tonnes.
Copper futures advanced in London and New York on Wednesday on hopes of rising demand, but prices in Shanghai fell on fears of policy tightening by top consumer China.
By disrupting mining activity, the coronavirus pandemic affected platinum supply much more than demand, pushing the roughly 8-million ounce market into a deficit of 932,000 ounces last year.
The leak of 21,000 tonnes of diesel into rivers and subsoil from a rusty-looking storage tank at mining firm Nornickel's power plant in Siberia angered President Vladimir Putin.