The blast occurred late on Wednesday at the Xinyao mine in the Shanxi province. However, managers did not report the accident until early on Thursday. Xinhua quote authorities as saying the delay probably increased the number of fatalities.
According to rescue officials, at least 120 miners were inside the mine at the time of the accident. Fifteen miners were rescued or managed to escape, Xinhua said.
Initial reports said the accident was caused by illegal mining in an unauthorized coal seam.
The Chinese coal mining industry remains the world's most dangerous, and accidents generally peak in the run-up to the winter period as coal producers attempt to boost output.
According to Chinese government statistics, a total of 1,920 coal mine accidents, in which 3,069 miners died, were registered in the country from January to October 2007.
An average 13 workers die each day in China's mines.
