TAIYUAN -- Five miners have been trapped after a coal mine accident in North China's Shanxi province, according to Datong Coal Mine Group.

The accident happened at 2:45 pm Tuesday when the roof suddenly caved in at a working platform in a coal mine operated by a company of the group. Of the 13 miners working at the platform, eight came out of the mine safely.

Rescue work is underway. By about 3:30 am Wednesday, rescuers had established contact with the trapped miners.

A preliminary investigation showed that the accident was caused by the collapse of the supporting structure due to lamprophyre.