A strike at the Escondida copper mine in Chile, the world's largest, appeared far from ending on Monday as the conflict neared its third week, with the union denying a news report that it had returned to talks with mine owner BHP Billiton.
Escondida's approximately 2,500 workers began a strike on Feb. 9 after contract talks with BHP failed, pushing global copper prices higher on expectations of tighter supply.
The mine produced about 5 percent of the world's copper in 2016.
Last week, the two sides briefly returned to the table for government-mediated talks, though the discussions ended after one meeting.
The union told Reuters on Monday it had not been approached about resuming talks and denied a report quoting the BHP chief executive officer saying the two sides were back at the table.
Relations have been frosty, with BHP accusing the union of preventing non-union maintenance workers from entering the mine, and the union saying that BHP has failed to make back payments to workers.
"That's the way the company starts to insult the workers, to scare and pressure them, and leave them without money ... That is making workers angry," union spokesman Carlos Allendes said.
BHP has said that it would pay the money that is owed once the strike ends, in accordance with Chilean law.
The workers have continued construction of a camp set up outside Escondida in Chile's barren high desert, which the union says will provide comfortable conditions in the event of a prolonged strike. In recent days, they have built a basic movie theater and sporting arena.
BHP will not replace striking workers for at least the first 30 days of the work stoppage to show that it is committed to negotiations, according to the company.
Under Chilean law, unionized workers can cross the picket line and individually accept the company's contract offer after 30 days on strike, potentially weakening the union's hand.
The contract talks relate to pay, bonuses and other conditions, with disagreement principally over the status of new workers and proposed changes to shifts and benefits.
Escondida is majority-controlled by BHP with Rio Tinto and Japanese companies including Mitsubishi holding minority interests.