At least 11 persons were killed and one was missing after a fire broke out at an illegal mine in China's Liaoning province, officials said on Friday.The mine near Benxi city caught fire on Monday, trapping 13 miners, Xinhua news agency reported.One person was rescued on Thursday while the rescuers were searching for the missing miner, officials said.The colliery was shut down in 2004, but its owner secretly continued operations by building a coal washing plant and hiding the shaft within it, an official said. A normal mine shaft should have at least two openings, one for miners and the other for coal, which can also ensure ventilation, but the illegal mine only had one, the official said.