Jakarta.While US mining giant Freeport-McMoRan may have been at loggerheads with the Indonesian government over divestment, it apparently has more homework in settling disputes with its workers.

A major labor union representing workers at Freeport Indonesia, the local unit of the US miner, and workers of its contractor companies at the mining site in Grasberg, the world's second-largest copper mine, have called on president Joko "Jokowi" Widodo to intervene in what they believe is a "mass layoff," affecting more than 8,000 workers.

"We call on related ministries and the president to preside over this issue," Afif Johan, a representative of the Freeport Indonesia Labor Union.

The union said the company has made an "unfair" furlough to cut costs after weeks of production outage, amid uncertainty over its contract re-negotiation with the government.

"In March-April, when Freeport Indonesia could not export its concentrate, we furloughed 10 percent of our employees [including contractors] ... since April we've been allowed to export, and our production has returned to normal," Riza Pratama, vice president for corporate communication at Freeport Indonesia told the Jakarta Globe.

He said the company was forced to reduce its production to 40 percent.

Freeport, according to Riza, has called on those who were temporarily suspended to return to work after its export permit was issued, but for one month they did not return.

"We have followed an industrial working agreement procedure, by which a worker who is absent without notification for consecutive five days is considered to have resigned, no one was fired," he explained, adding that Freeport has paid its obligations to workers in accordance with their working agreements, and advises them to apply for work through contractors.

In August, the government allowed the world's largest cooper producer to keep operating its Grasberg cooper and gold mine, as Freeport agreed to divest a 51 percent stake — a requirement that is set upon miners under Indonesian law.