A MECHANIC WAS WELDING ON THE TUBING OF BORE MINER #2 IN THE LAST OPEN X-CUT IN PANEL L23, DURING A BELT MOVE. HE WAS USING A TMX 412 AS A CONSTANT MONITORING DEVICE. SPARKS FROM WELDING FELL TO THE FLOOR CAUSING A IGNITION OF A BLEEDER IN THE FLOOR. THE FOREMAN PUT IT OUT IN 2-3 MINUTES.