INJURED WAS PERFORMING MAINTENANCE ON A CONTINUOUS MINER. WHILE USING A LIFTING JACK TO SPREAD METAL ONT HE UNIT HE WAS USING A PIECE OF DRILL STEEL TO OPERATE THE JACK. THE DRILL STEEL BROKE AND INJURED FELL BACK AND SPRAINED RIGHT WRIST. THIS HAPPENED ON THE SRUFACE AND NO RULES WERE BORKEN AND INJURED WAS SUFFICIENTLY TRAINED TO PERFORM THE TASK. DRILL STEEL IS OFTEN USED AS HAN