EE WAS OPERATING THE 12 CM IN THE #2 ENTRY. HE STEPPED OVER TO THE MIDDLE OF THE ENTRY TO CHECK THE CENTER LINE WHEN A PIECE OF ROCK FELL MEASURING 5' X 3' X 2"" TO 3"". THE ROCK STRUCK HIM IN THE HEAD KNOCKING HIM DOWN. HE WAS TRANSPORTED TO BOONE MEMORIAL WHERE X-RAYS WERE NEGATIVE. HE WAS DIAGNOSED WITH A CONTUSION TO THE BACK & NECK.