Striking workers have yet to return to Freeport-McMoRan's copper and gold mine in Indonesia's Papua region as they await the outcome of further talks.
According to Reuters news agency, more discussions between the union and the firm's local CEO are to be completed before the official end of the strike.
A late-night deal was struck on Monday to end the week-long stoppage that has paralysed output, but the union is threatening to revoke the agreement if its demands are not met.
The union said it wanted the company to include its Indonesia CEO Armando Mahler in negotiations over pay, plus talk to Freeport's chairman James Moffett, as well as to sack some management members for the strike to end.
