THE EE WAS OPERATING A FLETCHER ROOF DRILL, WHEN A PIECE OF ROCK FELL HITTING THE EE ON THE BACK. ROCK WAS 4""X 19""LONG X 3"". EE WORKED HIS USUSAL JOB WITH NO PROBLEM UNTIL 8/26/03. HE CALLED I N ON THAT DAY AND SAID HE WAS GOING TO THE DR. ABOUT HIS ACCIDENT OF 7/7/03. HE HAS NOT RETURNED.