The talks at Collahuasi - a partnership between Glencore and Anglo American with Japanese firms - were widely seen as the most sensitive of 2020 in top copper producer Chile, both because of the size of the union involved and the mine`s importance to the country´s total output.

"We have reached a collective agreement with the company to the satisfaction of both parties," Felipe Román, president of the union, told Reuters.

Earlier in the day a source with knowledge of the talks had told Reuters that labour and management had a struck the deal well ahead of the negotiation deadline of October 30.

The new contract takes effect on November 1.

Copper prices have been supported recently by concern about potential strikes in Chile.

Elsewhere, the talks have not gone well.

A union of workers at Lundin Mining´s much smaller Candelaria copper mine in Chile walked off the job on Thursday after talks broke down this week. A supervisors union at BHP´s Escondida copper mine, the world´s largest, rejected the company´s final offer on Friday and a strike is imminent there.

Collahuasi is one of Chile´s largest mines. It produced 565 t of copper in 2019.