It was originally thought seven miners were underground at the time of the collapse, but it was later found one miner had not tagged on to his shift, and was also trapped.

The accident happened at the Xieqiao Coal Mine in Fuyang, a city in the eastern province of Anhui, official news agency Xinhua said.

The cause of the cave-in has not been reported, but coal mine accidents are often attributable to lack of necessary safety equipment or indifference to safety rules.