Around 550 workers represented by the Candelaria AOS Union can now legally strike from October 20. They will join around 350 members of the Mine Workers Union who began industrial action at Candelaria on October 8 after earlier mediation talks ended without success.

“Critical works will continue... to protect required on-site personnel, the operation and the environment,” Lundin said.

“The company sincerely regrets having to take this action and its impact [it will have] on our workforce, [the] local community, suppliers, customers and many [other] stakeholders,” it added.

Lundin has an 80% stake in Candelaria, with Japan’s Sumitomo owning the remaining 20%.

The mine, which also produces gold and silver, is located in the northern Atacama region of Chile, and produced 146,330 tonnes of copper in 2019.

The company said that previously issued production, cash cost and capital costs guidance for Candelaria for 2020 should no longer be relied upon.

In July, Lundin further scaled back its 2020 group copper production guidance due to ore hardness, operational issues and unplanned maintenance stoppages at Candelaria. It specifically reduced its 2020 production forecast for Candelaria to 145,000-155,000 tonnes, down from 160,000-175,000 tonnes previously.

Lundin has operations in Brazil, Chile, Portugal, Sweden and the United States, primarily producing copper, zinc, gold and nickel.

Spot treatment and refining charges (TC/RC) have been driven lower this year amid supply disruptions resulting from efforts to fight the spread of the Covid-19 pandemic, particularly at copper operations in South America.

Fastmarkets’ copper concentrates TC/RC index, cif Asia Pacific, was $44.60 per tonne/4.46 cents per lb on Friday October 16, down from $45.60 per tonne/4.56 cents per lb in the previous week, amid a flurry of smelter deals below $50 per tonne/5 cents per lb.