EE WAS OPERATING A DOUBLE BOOM ROOF BOLTER, & ASHE WAS PREPARING TO TRAM THE MACHINE FORWARD TO SET UP FOR THE NEXT ROW OF BOLTS TO BE INSTALLEDA PIECE OF ROCK FELL OUT FROM BETWEEN THE PERMAN ENTLY INSTALLED ROOF BOLTS. THE PIECE OF ROCK STRUCK HIM ON THE TOP OF THE LT. HAND CAUSING A LACERATION THAT REQUIRED 7 STITCHES.