JAKARTA, Sept 16 (Reuters) - Indonesian coal miner PT Bayan Resources Tbk has declared force majeure after heavy rain disrupted production at its Wahana coal mine in South Kalimantan, the company said on Tuesday.

"We are still monitoring the situation. We don't know how bad it is," said Jenny Quantero, the company's corporate secretary.

She did not say how long the force majeure, which was imposed on Friday, might be in place, but said it might mean this year's production target of 9 million tonnes had to be lowered.

Coal from the Wahana mine is sold to international traders include trading firm Vitol.

Wahana mine in Satui regency, which is operated by Bayan's subsidiary PT Wahana Baratama Mining, started open pit mining in December 2007, according to the company's prospectus.

As of March 2008, the mine had produced 188,600 tonnes of coal with mineable bituminous coal reserves of 14.5 million tonnes.

The force majeure was the latest disruption to Bayan's coal operations.

In July, East Kutai regency in East Kalimantan ordered coal miner PT Perkasa Inakakerta, a subsidiary of PT Bayan Resources and another coal firm, to stop operating in some areas because it said they did not have permits from the forestry ministry.

Local forest rangers had shut the road used by the coal firms but re-opened it in late August.

Bayan Resources has previously forecast its coal production would rise to 13-14 million tonnes in 2009.

Indonesia, the world's largest thermal coal exporter, expects to produce 205 million tonnes of coal in 2008, with domestic demand seen at 52 million tonnes and the remainder to be exported, energy ministry data showed. (Reporting by Fitri Wulandari; editing by Ben Tan).

Source: Yahoo! Asia News & Reuters