By Rupert Wingfield-Hayes BBC correspondent in Beijing

China's state-run media has revealed what it says is an attempt to cover up a major mine disaster in the north-west of the country.

At least 21 miners were trapped underground when an explosion ripped through the mine earlier this month, but instead of trying to rescue them, the mine's owner is reported to have tried to literally whitewash over what had happened.

Perhaps the most surprising thing about the story is that it was reported at all

Grisly disasters are an almost daily occurrence in China's vast and chaotic mining industry, but the story of this latest one is particularly chilling.

On 4 May a huge explosion ripped through the small unlicensed mine in the heart of China's coal-belt. More than 20 miners were trapped below ground.

Instead of launching a rescue, the mine's owner destroyed employee records and whitewashed over the scorch marks made by the explosion on the entrance to the mine-shaft.

Only after three days did news of the disaster leak out. By that time, 21 miners trapped below ground were dead.

Media watchdog

But perhaps the most surprising thing about the story is that it was reported at all.

Thousands of small mines are running illegally

Last year more than 5,000 people were killed in China's mines, but few of the accidents were ever reported.

The growing public outrage at the endless stream of deaths may now be prompting China's government to use its official media to expose the criminal behaviour of many mine-owners.