EE WAS OPERATING AN HDDR-13 WALK-THRU ROOFBOLTER IN THE RIGHT CROSSCUT OF THE #6 ENTRY WHEN A PIECE OF ROCK MEASURING 0-6"" THICK X 34.5"" LONG X 21"" WIDE FELL FROM BETWEEN THE BOLTS STRIKING HI M ON THE HEAD & NECK. HIS INJURIES WERE DIAGNOSED AS A CONTUSION/ABRASION & HE WAS INSTRUCTED TO MISS 2 DAYS.