Rescuers early on Friday recovered six more bodies from a coal mine shaft in southwest China, where a gas explosion occurred on Thursday, bringing the death toll to seven, according to Xinhua. Four miners remained missing, said a source at the headquarters of the rescue operation at Yuejin Coal Mine in an outlying district of Chongqing. The blast occurred at 5:10 p.m. on Thursday at the mine in Yulong Village, of Nanping Township, Nanchuan District, while 14 miners were working below ground. Three were hoisted to the surface unharmed and the rest were trapped. The rescue operation is continuing and rescue workers said the ventilation system in the shaft was partially restored. An investigation into the accident is underway. Yuejin Coal Mine was a small, legally operated mine capable of producing 30,000 tons of coal a year, according to local officials.