Thousands of workers at a massive U.S.-owned gold and copper mine in eastern Indonesia are threatening to extend a crippling labor strike into December, if negotiators fail to reach a deal this week on worker pay.

Workers at the Freeport-McMoRan mine in eastern Papua province have been on strike over pay since mid-September, slashing production at one of the world's largest mining operations. Workers claim they are among the lowest paid miners in the world.

A deal would also end worker roadblocks on the Grasberg mine's supply routes and allow for a speed up in repairs to pipelines carrying copper concentrate to the coast. The pipelines were damaged in mid-October by suspected saboteurs.

Last month, unidentified gunmen opened fire near the mine, killing six substitute workers in two separate attacks.

The mine last year reported sales revenue of more than $5 billion. It is the largest single taxpayer to the Indonesian government, having paid on average more than $1 billion a year to the Jakarta government since 1991.