MINER WAS RELIGHTING A BURNER THAT WENT OUT ON THE FURNACE. THE MINER DID NOT SHUT OFF GAS BUILDUP BEFORE RELIGHTING THE BURNER. WHEN THE BURNER WAS LIT THE BUILDUP OF GAS IGNITED, STARTLING H IM. HE JUMPED DOWN OFF OF THE 3RD RUNG OF A LADDER AND INJURED HIS RIGHT KNEE.