The death toll from a coal mine explosion in central China's Henan Province has risen to 31.<br /><br />6 miners are still trapped underground, but officials say their chances of survival are very slim.<br /><br />More than 2,500 tons of coal dust smothered the pit after the blast.<br /><br />The accident occurred Friday morning in a pit owned by Pingyu Coal & Electric Co Ltd based in Yuzhou City. An explosion at the same mine two years ago killed 23 people.<br /><br />China's mines are the deadliest in the world, due to lax safety standards. More than 2,600 people died in coal mine accidents in 2009 alone.
