EMPLOYEE WAS OPERATING A DOUBLE BOOM ROOF BOLTER & AS HE WAS IN THE PROCESS OF INSTALLING A TUBE OF RESIN INTO A DRILLED HOLE A SMALL PIECE OF ROCK THAT FEATHERED OUT ON ONE SIDE TO A FINE EDGE FELL FROM ROOF & STRUCK EE ON THE LT. FOREARM. HE RECEIVED FIVE SUTURES TO CLOSE THE LACERATION. HE RETURNED TO WORK HIS NEXT SHIFT, MISSING NO SCHEDULED WORK TIME.