It has been struggling to improve standards in its mines, but accidents are common as owners stretch production beyond safety limits to meet high demand to fuel the country's economic boom.
In a separate incident in Shanxi, Xinhua reported that a landslide in the country's north had buried a brick factory, killing at least 16 workers.
Rescuers are working to pull out two others who remain trapped after the landslide hit on Friday morning near Luliang town in the country's north, Xinhua said on Saturday.
One other worker has already been pulled out.
Rescue efforts were suspended overnight because of fears of a second landslide in the area.