The case relates to Newmont Minahasa Raya's tailings disposal processes, which allegedly involved dumping mercury and arsenic into Buyat Bay in the Sulawesi region, making villagers sick as a consequence.

PT Newmont Minahasa Raya president director Richard Ness, a 55-year-old American from Minnesota, could face a jail sentence of up to 10 years and be fined around $68,000 if convicted.

"I never had this disease before Newmont operated in the area ... and fewer fish were caught since they operated and affected our income," said Rasyid Rachmat, 39, a local fisherman who said he developed a lump on the back of his neck.

The Newmont gold mine near Buyat Bay, 2,200 km (1,400 miles) northeast of Jakarta, opened in 1996 and closed in August 2004 due to depleted reserves.

Newmont has vigorously denied any wrongdoing and said its disposal processes were properly approved by the government.

"No urine, blood or hair data (was) obtained. There is no evidence to support the allegation" the mine caused illness, Blake Rhodes, a Newmont attorney working on the case, had told reporters in Jakarta at a news conference this week.

One of the witnesses on Friday was an Indonesian doctor, who filed complaints to the police last year that the Denver-based company polluted the bay, helping bring about the launch of a criminal investigation.

However, Newmont had in turn brought a defamation case against her, which was dropped after she said her allegations were not backed up by scientific and comprehensive proof.

She told the Manado court her diagnosis was "premature".

Last December, a $543 million lawsuit by Buyat Bay villagers was dropped at a Jakarta district court on the grounds of insufficient proof that they became sick because of exposure to mine waste.

A study from the World Health Organisation and Japan's Institute for Minamata Disease found mercury levels in individuals, water and fish samples near the mine were not unusual, Indonesia's health ministry has said.

However, an inter-agency report found otherwise and a police report said Newmont exceeded limits of heavy metals in the waste.

Newmont's trial began in August and is expected to last into next year. More prosecution witnesses are due to be called on Oct. 14, the next session of the trial.

Newmont's operations in Indonesia accounted for six percent of its global sales in 2004.