All 18 of the miners who were buried underground after a gas explosion in a coal mine in central China\'s Henan province six days ago have perished, according to local rescuers. The accident occurred at the Jiulishan Coal Mine in the city of Jiaozuo shortly after midnight Thursday, when 18 miners were working in the mine, according to a spokesman from the local rescue headquarters. The mine belongs to the Henan Coal and Chemical Industry Group, the province\'s largest state-owned mining company. An initial investigation showed that the mine\'s managers failed to take preventative measures to eliminate gas explosion risks, according to the spokesman. A further investigation is under way.