31 people were working underground when the disaster happened. 4 miners have been rescued to safety. Rescuers were searching for the 10 remaining miners trapped by the explosion. The cause of the accident is under investigation. News of the blast came just hours after 21 Chinese miners who were trapped for four days after an explosion hit their unlicensed coal mine were confirmed dead in northeast China’s Heilongjiang province. Chifeng, the place where occurred the actual blast, is situated along the upper reaches of the Xiliao River. The area is rich in coal, oil and gas; nonferrous metal and ferrous mental, namely iron, tin, zinc, lead, gold, silver, molybdenum etc. have large reserves. Non-metal minerals include limestone, marble, fluorspar, silica, pearlite, bentonite etc. Chifeng’s airport has service to major cities such as Beijing, Hohhot, and other cities.