Rescuers are struggling to put out a colliery fire that has kept burning since Wednesday night in north China, and search for the 15-trapped miners, Xinhua reported. A total of 36 miners were working in the shaft when the fire broke out at the Huquangou coal mine in Zuoyun County, Shanxi Province, at 11 p.m. on Wednesday and 18 miners managed to escape. Rescuers found three bodies in the shaft at 7:00 a.m. on Thursday and 15 others remained trapped underground. "It is not clear whether the 15 trapped miners are still alive or not, and the fire is yet to be quenched," said Wang Xingui, deputy head of the rescue headquarters, on Sunday. He said rescuers had tried to use pipe water and liquid nitrogen to extinguish the fire, but failed due to roaring blaze. "Rescuers managed to enter the pit through another entrance Saturday evening, but heavy smog lowered the visibility to less than three meters down in the shaft, blocking them from continuing their search," he said. Rescuers are studying other possible ways to put out the fire, he added. Huquangou is a fully licensed coal mine with a designed output capacity of 150,000 tons a year. Preliminary investigations show that the coal mine fire was caused by an underground cable that caught fire.