This year, Anglo American needs to negotiate contracts with seven unions in Chile amid low prices for the red metal.

"We're conversing within an early (wage negotiation) process with the two unions at our Los Bronces operation whose contracts expire at the end of August this year," a company spokesman said.

"Agreements have already been reached and signed with the supervisors' union and with the two unions at the Chagres (smelter)," the spokesman added.

Los Bronces produced 401,715 tonnes of copper last year.

Anglo American is also in negotiations with workers at the smaller El Soldado mine, where workers said on Friday that they would vote on a strike next week after receiving an offer from the company that they deem insufficient.

El Soldado produced 35,840 tonnes of the red metal in 2015.

(Reporting by Fabian Cambero; Writing by Gram Slattery; Editing by Sandra Maler)