A ROOF ROCK (MEASURING APPROX. 4' X 3' X 5"" AND LESS IN THICKNESS) FELL OUT BETWEEN THE LAST 2 ROWS OF BOLTS IN THE 3 RIGHT/LEFT ROOMS OFF OF I-1 SUBMAINS, SPAD 8367. THE ROCK STRUCK THE INJUR ED ON THE BACK OFTHE LEFT HEEL RESULTING IN AN AVULSION WHICH REQUIRED SURGERY.