The Toronto, Canada-headquartered company withdrew its 2020 production, cash cost and capex guidance for Chapada in September after a power outage caused damage to all four of the mills' motors.

Lundin said Monday it had over the weekend completed installing the last remaining repaired and more powerful motor on the ball mill. The plant achieved about 35% of capacity while operating only the SAG mill and throughput further improved mid-November with the installation of a single motor on the ball mill.

Chapada's copper and gold output had already achieved the lower bound of the 2020 guidance range of 45,000-50,000 tonnes copper and 80,000-85,000oz gold, and it was said to be "well-positioned" to deliver on the 2021 guidance. The company said it had used the downtime to pull forward maintenance, to build the run-of-mine ore stockpile and advance waste removal and development activities.

Lundin recently provided guidance through 2023 for producing 300,000tpa copper with output increasing 25% in 2021 to 275,000-299,000t due to increasing grades at the Candelaria mine in Chile, and an expected year of uninterrupted operations. Gold output is forecast to average 170,000-175,000ozpa while zinc production will grow from about 141,000-151,000t in 2021, to 221,000-236,000t in 2023 due to increased production from the Neves-Corvo mine, in Portugal.

Lundin shares (TSX:LUN) last traded at C$10.38, which capitalises the company at $7.6 billion (US$5.9 billion).