EMPLOYEE WAS REINSTALLING A DISCHARGE ROLL USING A TOW MOTOR TO MANEUVER IT. ANOTHER EE WAS OPERATING ANOTHER TOW MOTOR TO GUIDE AND SUPPORT ROLL. AN ADDITIONAL TOW MOTOR WAS USED TO STABILIZE ROLL. ROLL HIT EE'T TOE MOTOR. IN THE PROCESS,HE PUT HIS HAND UP ON CAGE OF TOW MOTOR AND HIS HAND CAME IN CONTACT WITH SHARP EDGE OF ROLL. IT CUT HIS HAND.