EE HAD INSTALLED THE FIRST BOLT IN THE ""NEXT TO LAST ROW"" OF BOLTS. HE SWUNG HIS BOLTER IN TO INSTALL THE INSIDE BOLT WHEN A ROCK FELL AND HIT EE ON THE FOOT. THE ROCK MEASURED 40"" BY 40"" BY 3 "" THICK. THIS REPORT IS LATE DUE TO AN OVERSIGHTIN THE SAFETY DEPT.