(Adds comment from Freeport, paragraph 6)
TIMIKA, Indonesia, May 1 (Reuters) - Thousands of workers from the Indonesian unit of Freeport McMoRan Inc FCX.N staged a rally near its Papua mine on Monday, a union leader said, protesting against layoffs by the miner due to a contract dispute with the government.
The union representing a third of the 32,000 workforce sent a notice to Freeport on Monday threatening to strike from May 1 to the end of the month at the Grasberg mine, the world's second-biggest copper mine.
Freeport is trying to ramp up output and exports at Grasberg after reaching a temporary deal with the government following a 15-week stoppage linked to new mining rules, but customers are concerned that labour unrest could now hit supply. had laid off about 10 percent of its workforce and warned it could cut another 5,000 to stem losses, sparking protests from workers. are still waiting. We have good intention by opening up in a transparent and fair manner so the problem can be solved. We actually don't want a strike to happen," said union leader Aser Gobai, adding that about 8,000 workers had participated in the rally in Timika, the nearest town to the mine.
Freeport said in an emailed statement that its Indonesia unit "continues to work with union leaders, with the support of government officials, to encourage a safe and efficient return to normal operations for the benefit of all stakeholders."
Freeport Chief Executive Richard Adkerson said last month the company could punish workers for absenteeism. delays in resuming exports could support copper prices. London Metal Exchange prices CMCU3 were last at $5,735 a tonne, up 4 percent this year.
Adding to tensions around Grasberg, several Freeport workers and police were injured in a clash in Papua last month, when officers fired tear gas and rubber bullets at demonstrators in Timika who authorities said had been attempting to free a union leader at a court hearing.
New rules in Indonesia require Freeport to obtain a new mining permit, divest a 51 percent stake, build a second copper smelter, relinquish arbitration rights and pay new taxes and royalties.
Freeport insists any new permit must have the same fiscal and legal guarantees as under its 30-year mining contract, and in February it served notice to Jakarta, saying it has the right to commence arbitration if no agreement is reached by June 17.