While bolting with a fletcher twin boom bolter in the #9 entry on the rt side of the mains, at the overcast area a piece of draw rock measuring 1'x1'x6"" fell from approximately 10' between the canopy and the ATRS striking the miner on the top of his head. The miner continued to work until around 1:00 pm and then came out of the mine and was transported to Wheeling Hospital