WHILE ROOF BOLTING AND INSTALLING A FULLY GROUTED 6 FOOT BOLT THE BOLT AND PLATE POPPED OFF THE DRILL POT UNEXPECTEDLY STRIKING THE BACK OF THE OPERATOR'S HAND WITH THE SHARP EDGE OF THE PLATE, CUTTING THROUGH HIS GLOVE AND LEAVING A LACERATION ON HIS LEFT MIDDLE FINGER THAT REQUIRED SUTURES TO CLOSE. RELEASED TO FULL DUTY.