Steam hisses constantly from boreholes as water is pumped into a 200-metre-deep coal bed, while dozens of bulldozers nearby shovel red-hot gravel along hillside surfaces.

This was the scene at a key firefighting site yesterday at the Tielieke coalfield fire area in Tielieke Township, Aksu, about 1,100 kilometres southwest of Urumqi, the capital of Northwest China's Xinjiang Uygur Autonomous Region.

China's coalfield fires are mainly in Xinjiang, Inner Mongolia and Ningxia, which together have more than 80 per cent of China's total coal reserves.

The fires in these coalfields cause an annual loss of 13 million tons of coal. Work is ongoing to put them out although some have been burning in the region for nearly ten centuries.

"We can put out coalfield fires by drilling bores, infusing water and slurry, and covering the fire with loess," said Qi Dexiang, head of the Xinjiang Regional Coalfield Fire Fighting Project Office. It was established in 1958 to extinguish coalfield fires plaguing the region.

"First, we drill into the ignited coal bed and then pump water and slurry into it to lower the temperature of the ignited coalfield, which may be as high as 1,000 C due to long-term burning. After the temperature falls, we cover the surface with loess to isolate the underground fire from the atmosphere and put it out," Qi said.

Xinjiang boasts an estimated coal reserve of 1.8 trillion tons, or 40.6 per cent of China's total. However, 33 sites in the region still have coalfield fires covering an area of 6.45 million square metres, devouring about eight million tons of coal a year and causing heavy pollution.

The self-ignition of exposed coal beds, colliery fires and a dry climate are the main causes of coalfield fires. "Compared with methods commonly used in some other countries, our way of extinguishing coalfield fires is effective and costs much less," Qi said.

With a specialized team for extinguishing the fires and 47 years of firefighting experience, the office has effective technology to find, extinguish and monitor coalfield fires, according to Qi.

The century-old Liuhuanggou coalfield fire in the region, China's worst in terms of the ignited area and loss of coal, was extinguished in late 2004 after four consecutive years of effort by the team.

"We vow to put out all coalfield fires in the region by 2015," said Qi, adding that this aim reduces the original schedule by five years, thus saving about 24 million more tons of high-quality coal.

With the financial support of the central government, five key coalfield fires in the region were put out between 1984 and 1999, preventing a loss of 30 billion tons of coal.

Wu Yin, deputy director of the Energy Bureau of China's National Development and Reform Commission, affirmed the progress in extinguishing coalfield fires in Xinjiang.

"To protect the rich coal resources in Xinjiang, the central government will continue to financially support fire extinguishing work," he said last month.

The achievements in extinguishing coalfield fires in Xinjiang show they can be extinguished with scientific methods despite some difficulties, said Wu.

"With advanced technology and equipment, we can now detect any underground coalfield fire," said Qi Weipeng, manager of the Tielieke coalfield firefighting project.

"When we have put out all coalfield fires in Xinjiang (by 2015), we may go to Inner Mongolia and Ningxia too, to offer our expertise to help put out the fires there," he added.

(China Daily October 24, 2005)