EMPLOYEE WAS PREPARING TO LEAVE THE SECTION AT THE END OF HIS SHIFT. AS HE REMOVED OLD BITS FROM THE BOLTER, A 12""X 8""X 1""ROCK FELL ONTO HIS RIGHT HAND JUST BEHIND THE THUMB CUTTING HIM. HE WAS TAKEN TO THE E.R. FOR TREATMENT, WHERE THE WOUND WAS CLOSED WITH STITCHES.