Liang Jiakun, deputy director of the National Safe Production Supervision and Administration Bureau, said yesterday the governent has granted favourable policies including tax reductions or duty exemptions to attract enterprises into controlling gas discharges.

The Chinese Government has already invested 5.3 billion yuan (US$610 million) in the past three years to enhance coal mine safety.

The money has mainly been used to improve the release of the gas, allowing it to drain deep from below underground coal beds through various ventilation systems.

Liang also said the improvements are a bid to better use the methane as an energy resource rather than send it straight into the air where it can cause global warming.

However, Liang said he feels sorry that more than 40 per cent of Chin's coal mine accidents have been caused by the gas, which can also result in deadly explosions.

Liang said the government has set up long-term goals to stop coal mine accidents and deaths. He revealed the goals yesterday at the two-day International Symposium on Coal Bed Methane in China, which was organized by China Coal Information Institute.

The institute's President Huang Shengchu said the government has paid great attention to coal bed methane, noting that methane reserves, estimated at 33,000 billion cubic metres, are generally found at 2,000 metres underground.

To prevent gas explosions, China emits millions of cubic metres of methane from mines a year, adding serious pollution to the environment and wasting energy resources.

Although the concentration of methane and nitrous oxide in the air is far less than that of carbon dioxide, their greenhouse effects are more than 20 to 300 times that of carbon dioxide, respectively, Huang said.

However, methane is different from carbon dioxide because it is also a form of energy, he said.

Reducing methane is therefore one of the most important and economical measures that can improve the environment while aiding economic development.

The government considers coal bed methane a spare energy resource, following oil and natural gas, and has designed preferential policies for its development at mines, he said.

According to Huang, China's coal output will reach 1.9 billion tons this year, and the output was 1.6 billion tons last year. With that growth, methane discharges also increase.

Surveys done by the United Nations Development Programme and the US Environmental Protection Agency estimate that annual coal bed methane emissions in China stands at 12 billion cubic metres.

In comparison, only about 1.5 billion cubic metres of methane in China was vented from coal mine drainage systems last year.