The workers at the mine entered mediation with the government over salaries and benefits on July 15, in a last-ditch bid to stave off a strike amid a coronavirus outbreak in the South American nation.

"Mediation was extended to see the results of the assemblies," the source told Reuters, referring to workers' meetings to discuss a company proposal.

Antofagasta declined immediate comment.

Chilean law allows the workers and the company to extend talks again after five days of mediation if an agreement is not reached.

Zaldivar, which is co-owned by Barrick Gold Corp, accounts for about 2% of Chile's annual copper production.

By Fabian Cambero