ZHENGZHOU -?The bodies of six miners trapped in a rock burst at a coal mine in central China's Henan Province were found by rescuers on Friday.

The burst happened at 11:18 am on Thursday, when 18 miners were working in a shaft of Qianqiu Coal Mine, owned by the Henan Yima Coal Industry Group. Twelve miners escaped.

Rock burst accidents are often caused by fractures in the rock because of mining. They can trigger mining lanes to cave-in, leading to casualties.

Qianqiu Coal Mine suffered a major rock burst accident in 2011, when 10 workers were killed.