TIMIKA, Indonesia (AP) -- Rescuers at a giant U.S.-owned mine in eastern Indonesia have freed four out of 37 workers who were believed trapped underground Tuesday when a tunnel collapsed, the company said.
The accident occurred when 40 employees and contract workers were gathered in a classroom inside a training tunnel about 500 meters (yards) from the entrance of the Big Gossan Mine in Papua province, according to a statement by PT Freeport Indonesia, a subsidiary that runs the mine owned by Freeport-McMoRan Copper & Gold Inc.
Three workers escaped unharmed, while four others were later freed by rescuers, it said. Of those, one was taken to a hospital in stable condition, two were being prepared for medical evacuation and the fourth victim's injuries were being evaluated, it said. No information was provided about possible fatalities.
"The rescue process is difficult and will take some time to complete," the company said. "Our thoughts and prayers are with our fellow employees and their families as we proceed with rescue efforts."
More than 20,000 workers are employed at the mine in the remote Mimika district, which has been plagued by violence since work began in the 1970s. In 2011, production was crippled when 8,000 unionized employees walked off the job after demanding higher pay. The strike ended after the company agreed to a 37 percent wage hike and improved benefits.
The restive province holds some of the world's largest gold and copper reserves.
Freeport-McMoRan Copper & Gold is based in Phoenix, Arizona.