Photo taken on Dec. 15, 2014 shows the portal of a coalmine in which explosion occurred at the Xingyun Colliery in Jixi City, northeast China's Heilongjiang Province. Ten people trapped underground after the gas explosion at Xingyun Colliery have died, according to a statement from the provincial production safety supervision and administration bureau. The explosion occurred at 10:10 a.m. on Sunday. The cause of the accident is being investigated. (Xinhua/Wang Kai)