The final remaining repaired motor on the ball mill was installed on December 20, 2020, said the company, noting that the processing plant only achieved approximately 35% of nameplate capacity while operating only the SAG mill.

Throughput had improved mid-November with the installation of a single motor on the ball mill, and production of both copper and gold have achieved the lower bound of the 2020 guidance range - 45,000-50,000 t of copper and 80,000-85,000 oz of gold.

"Chapada is well positioned to deliver 2021 guidance having used the opportunity to accelerate maintenance, build run of mine ore stockpile and advance waste removal and development activities," said the company.

Chapada, which is located about 270 km northwest of the capital Brasilia, suffered a power outage on September 27.

The main electrical substation's protection system failed when power was restored, Lundin said, resulting in significant damage to all four semi-autogenous grinding and ball mill motors.

Chapada is an open pit copper-gold mine owned and operated by Lundin Mining's Brazilian subsidiary Mineração Maracá Indústria e Comércio S/A.