A rock measuring 3'x 2'x 0"" to 5"" thick unknowingly sat down on the roof bolter canopy. While he was swinging the drill head over to install the 2nd bolt, he saw the rock coming off the top of the canopy. While moving out of the way of the falling rock, he hit his head on the mine roof causing pain to his neck and shoulders, he began losing time away from work on 05/17/2011.