A cigarette lighter's flame may have sparked the methane gas explosion in a coal mine shaft that led to the deaths of at least 46 men, a national television network reported.

Also Monday, mine owners defended the rescue operation despite the revelation that a radio operator told six trapped miners to get off a radio channel just hours after Wednesday's blast.The six were discovered alive Saturday after officials had insisted there were no signs of life in the Stolzenbach mine in Borken, 72 miles northeast of Frankfurt.

A statement from the rescue team said searchers had found another miner's body early Tuesday, bringing the total confirmed dead to 47. Four men were still missing in the mine's north field.