INJURED WAS BOLTING #4 FACE OF C-RT #2 PANEL WHICH HAD SOME ROCK FELL OUT. HE HAD ADVANCED THE BOLTER TO THE NEXT ROW AND WAS TRAMMING THE MACHINE ON TOP OF 8"" TO 10"" ROCK. AS HE CRAWLED FROM THE SIDE TRAM LEVERS TO THE HEAD LEVERS, HIS KNEE SLIPPED ON THE ROCK AND STRUCK ANOTHER ROCK.