HE AND A CO-WORKER WERE BUILDING THE LAST OF 3 CRIBS IN THE LEFT CROSSCUT OF #2 ENTRY, ON THE 5 NORTH SECTION (003 MMU), WHEN A PIECE OF ROCK FELL FROM BETWEEN THE ROOF BOLTS AND THE COAL RIB STRIKING HIM ON THE SIDE OF THE LEFT FOOT. THE ROCK WAS APPROXIMATELY 3' WIDE X 4' LONG X 0"" TO 8"" THICK.