EE WAS INSTALLING AN EXTRA BOLT BETWEEN THE RIB AND RIB BOLT. WHEN HE TIGHTENED THE NUT ON THE BOLT A PIECE OF DRAW ROCK FELL GLANCING HIS HEAD AND LEFT SHOULDER AND STRIKING HIM ON THE LEFT A RM CAUSING A LACERATION. EMT BANDAGED THE LACERATION AND HE WAS TAKEN TO THE HOSPITAL WHERE HE RECEIVED 14 STITCHES. THE ROCK MEASURED 18"" X 28"" X 1/2"" AND FELL APPROX 96"".