Coal mine gas blast kills 20 and traps 17 underground

Some 276 workers were in the mine when the blast happened, but officials said the rest managed to escape.

Rescuers were battling dangerous levels of poisonous gas and the risk of tunnel collapse as they worked to free those trapped in the Henan province mine.

The blast happened around 6am local time yesterday at the state-run Pingyu Coal & Electric Company pit as workers were drilling a hole to release pressure from a gas build-up to reduce the risk of an explosion, according to local safety officials.

They said the mine had been hit by a "sudden coal and gas outburst".

The mine is in the city of Yuzhou, a few hours outside the Henan capital of Zhengzhou and about 430 miles south of Beijing.

It was unclear how far underground the trapped miners were. Officials said the 20 dead had been located.

More than 70 rescuers faced excessive gas levels and chunks of coal loosened by the blast that had fallen into the shaft as they strove to rescue the trapped men.

According to TV reports, the gas level in the mine was 40 per cent, far above the normal level of 1 per cent.

China's mining industry is the most dangerous in the world - with 2,600 miners killed in accidents last year - and its leaders have been making a high-profile push to improve mine safety.

Prime minister Wen Jiabao has even ordered mining bosses to the coalface with their employees or risk severe punishment. Around 1,000 unlicensed pits have been closed down this year.

Henan was the scene of one of China's deadliest mining disasters, a gas explosion in the Daping pit that killed 148 in October 2004.

China had its own miracle mine rescue earlier this year, when 115 miners were pulled from a flooded pit in the northern province of Shanxi after more than a week underground. The miners survived by eating sawdust, tree bark, paper and even coal. Some strapped themselves to the walls of the shafts with their belts to avoid drowning as they slept. Mining fatalities have decreased in recent years as China has closed many illegal mines, but deaths increased in the first half of this year.

At least 515 miners were killed in accidents in China's 25,000 collieries this year before yesterday's blast.

An unknown number of illegal mines still exist in China to profit from the fast-growing economy's huge appetite for power.

Its industries remains reliant on coal for about two-thirds of energy needs and safety rules are often ignored by mining firms in pursuit of profit.

China's mines had 6,995 fatalities in 2002, their deadliest year on record.