528 workers were said to be in the mine in Heilongjiang province at the time of the blast on November 31 and rescuers were searching for those trapped.

Up to 400 other miners reportedly managed to escape the mine, which is reportedly operated by the state-owned Heilongjiang Longmei Mining Holding Group.

31 workers were killed and another 82 were still trapped about 500m underground.

Most mining accidents in China are blamed on the failure, and to follow safety guidelines, often in an attempt to cut costs to meet an increasing demand for fuel.

Beijing says safety is improving and the official death toll in 2008 marked a fall of 15% from the previous year.