Freeport-McMoRan Copper & Gold Inc.’s Indonesia unit suspended mining operations at its Grasberg mine in West Papua on Sept. 15, as workers started a strike that could last a month. According to Dow Jones Newswires, all workers at the mine are participating in the strike, which will last until Oct. 15 if the company refuses their demand for higher pay. Freeport suspended operations during a weeklong strike at Grasberg in July and lost about 35 million pounds of copper and 60,000 oz of gold output.

“We are disappointed that union workers decided to implement an illegal work stoppage,” PT Freeport Indonesia, which is 90.64% owned by Freeport-McMoRan, said in a statement. The company said that since July 20, it “has negotiated in a diligent good-faith manner” with the union toward a collective labor agreement to cover 2011-13.