TAIYUAN -- North China's Shanxi Province, the country's biggest coal-producing base, will close 900 more coal mines by June 2008 amid concerns over safety, environmental protection and resource conservation.

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Local authorities have listed 500 coal mines and the number could climb to 1,100 by June 2008, according to a circular issued by the Shanxi provincial government recently.

The measure is aimed at reducing the number of coal mines to 2,500 by 2010, the circular said.

Currently, the province has about 3,500 coal mines, a spokesman with the local coal industry authorities told Xinhua on Tuesday.

From July last year and this June, Shanxi shut down 1,156 coal mines, the spokesman said.

Shanxi, whose coal output accounts about one third of the country's total, has seen numerous coal mine accidents in recent years.

The latest accident, a gas blast on Sunday at the Jiaojiazhai Coal Mine of Xuangang Company under Datong Coal Mine Group in Xinzhou, a central-north city of the province, killed 19 miners and 28 miners remain missing.

Initial investigations suggest that gas accumulated and exploded after exhaust fans stopped working due to a power failure.

Unsafe small coal mines account for two-thirds of the total fatalities in mining accidents, government figures show.

The huge drain on natural resources and grave harm to the environment caused by the unsafe and unclean small mines have also made the closures more urgent.

The national coal mine safety watchdog has called for small mines with an annual output of below 30,000 tons to be shut down by the end of this year.

This year, 2,652 small mines will be sealed off in the country, and another 2,209 will be shut down next year.