Authorities have vowed to shut dangerous mines and increase safety, but the accidents continue [Reuters]

Rescue teams in China say there is little chance of finding anyone alive in a Henan province coal mine as the death toll from a gas leak at the mine rose to 30.

Chinese media announced the latest death toll on Monday, after rescuers found four more bodies at the mine in central China.

But at least seven other miners were still trapped underground, and officials warned that they could be buried under thousands of tonnes of coal dust.

Meanwhile, security was tightened outside the mine on Monday and journalists turned away, after some miners' relatives complained of poor safety conditions at the work site.

Little hope

Rescuers had said on Sunday that there was little hope of finding any more survivors in the colliery, and according to China National Radio, the "rescue and clean-up work was expected to be finished" before Wednesday.

Du Bo, deputy chief of the rescue headquarters, told the state-run Xinhua News Agency that hopes were slim that the men underground might have survived Saturday's early morning blast.

An initial investigation showed that 173,500 cubic metres of gas rushed out, Xinhua said, citing rescuers.

The outburst generated enough force to throw 2,500 tonnes of coal dust into the mine pit, it said. The gas wasn't specified, but methane is a common cause of mine blasts, and coal dust is explosive.

The gas level inside the mine, normally about one per cent, had reached 40 per cent, state media reported.

Unfavourable comparisons

The Chinese mine drama unfolded as the world was celebrating Chile's successful rescue of 33 miners trapped for more than two months.

On the internet reaction has been swift and bitter - with many making unfavourable comparisons to the situation in Chile.

"The Chilean miracle has signed the death warrant of the mine safety system in China," one user using the screen name Xiaodaoren wrote on sina.com's popular Twitter-like microblogging service.

"If we don't fundamentally resolve these mine security issues, the accidents will not stop and we will be unable to avoid the deaths and injuries."

Another, named Cheng Jing, 33, wrote: "The difference with Chile is enormous. The mines here are not inspected enough and poorly managed."

In harm's way

In July, Wen Jiabao, the country's prime minister, lamented China's "serious" work safety situation, ordering mining bosses to work side-by-side with workers in the pits to ensure companies observed safety rules.

Independent labour groups say the actual number of mine deaths last year is probably much higher than the seven people a day estimated by the government.

Authorities have repeatedly vowed to shut dangerous mines and increase safety, but the accidents continue with regularity as mines rush to pump out the coal on which China relies for about 70 per cent of its energy.

Two years ago, another gas blast at the same mine killed 23 people, state media said.

Source: Agencies