EE & CO-WORKER WERE REMOVING DEBRIS FROM MAGNET. AN END LOADER BUCKET WEAR PLATE WAS ATTACHED TO MAGNET. EE ATTEMPTED TO PULL WEAR PLATE AFTER A ROPE WAS ATTACHED BACK UP THE BELT TO PREVENT I T FROM FALLING INTO CHARGE CHUTE. WHEN THE POWER WAS REMOVED FROM MAGNET & AS HE PULLED, WEIGHT OF WEAR PLATE PUSHED HIS LEFT ARM DOWN ON A PIECE OF PLYWOOD PUT UNDER MAGNET TO CATCH OTHER DE