PT Freeport Indonesia (PTFI) has denied reports that the world's biggest gold and copper mining company was polluting rivers near its mining site in Papua.

The U.S.-owed firm has never violated any environmental legislation or regulations during its more than three decades of operations in the resource-rich province, Freeport spokesman Siddharta Moersjid told The Jakarta Post on Monday.

He said Freeport would comply with any regulations set by the government and would also protect the environment in Papua.

"PT Freeport Indonesia will work cooperatively with the State Ministry of Environment to address any concerns they may have, as we had always done in the past," he said in an email to the Post.

"We share the same goal, which is to continually improve environmental management," Siddharta added.

Earlier, the office of the State Ministry of Environment told PTFI to find alternatives to disposing of its hazardous waste rather than dumping it into the nearby Otomina River.

The tailings system, called Riverine Tailing Disposal (RTD), is considered by many environmentalists to be a practice of the past that is no longer acceptable.

According to the Mines and Communities website, such a method of waste disposal causes severe damage to water bodies and the surrounding environment.

However, Freeport's 2004 Working Towards Sustainable Development Report said a Tailings Review Committee, consisting of various government agencies and PTFI, concluded that RTD was the best option of the 11 available alternatives discussed by the team.

The assistant to the deputy minister of environment, Rasio Ridho Sani, has confirmed that PTFI had secured an AMDAL (environmental impact analysis), but said it was not a permit for it to dispose of its mining waste to the river.

"However, Freeport officials are very cooperative and we're hoping to grant the tailings disposal permit by mid this year," he said, adding that his office wanted the company to shift its tailings onto land.

Mining Advocacy Network (Jatam) executive director Siti Maimunah supported the call for PTFI to shift its tailings method as RTD violates government regulations on water sources protection.

"The regulations stipulate that tailings are not allowed to be disposed of into water sources," she said, projecting that up to the present, Freeport's tailing could reach 800 million tons.

Maimunah also said that with the company's production capacity increasing every year, the environmental capacity of the river could not accommodate the mining waste.

A study of PTFI's tailings system carried out by the Mining, Minerals and Sustainable Development organization said the disposal method was selected when production was only some 7,500 tones of ore per day.

PTFI's report said the company's production last year averaged 43,600 metric tons of ore per day.

Maimunah further said President Susilo Bambang Yudhoyono should take firm measures to resolve the problem.

"Why? Because the President had dealt with Freeport when he was once the minister of mines and energy," she added. Susilo held the ministerial post during the administration of former president Abdurrahman "Gus Dur" Wahid.

The Post reported in May 2000 that Susilo forced Freeport to cut its daily output by about 30,000 tons of ore to prevent landslides at the company's dumping site in Wanagon Lake, where earlier in the month a landslide had injured four workers.