Company said copper output, which dipped to 306,000 tonnes in 2020 from 311,000 tonnes in 2019, was expected to slip further in 2021 to between 275,000 and 295,000 tonnes.
The miner beat expectations with a small fall in 2020 earnings, but boosted dividend as soaring commodity prices helped it recover from covid-19 disruptions in the first half of the year.