More than 50 people are working at a flooded coal mine in northwest China's Shaanxi Province to rescue the nine miners who have been trapped for more than 30 hours but still have chances of survival, Xinhua reported. The accident occurred around 11:40 a.m. on Friday at the Yaotou Coal Mine in Chengcheng County, Weinan City when the No. 3 shaft was suddenly flooded. Fourteen miners were working underground but only five escaped, said the rescuers. "The gas density is rather low in the shafts of the coal mine, so there are still chances for the trapped miners to survive," said a spokesman for the rescue operation headquarters. But rescuers have not established contact with the missing miners. Eight pumps have been used to help drain the flooded shaft but the work is hampered by continuous flooding. The Yaotou Coal Mine, 20 kilometers from the county seat, is a registered private one with an annual output of 60,000 tons. Yaotou town is home to many private coal mines, which are prone to accidents.