Six workers were trapped on Thursday following a rock burst at a coal mine in central China's Henan Province.
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The burst happened at 11:18 a.m. when 18 miners were working in a shaft of Qianqiu Coal Mine, owned by the Henan Yima Coal Industry Group, said a group spokesman.
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Twelve miners escaped, said the spokesman.
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Rescue work is under way, and the cause of the accident is being investigated. Â