EE WAS BACKFILLING A DRILL BLAST HOLE WHEN HE HOOKED A ROCK HIDDEN IN THE DRILL CHIPPINGS. HE FELT A PAIN IN HIS LOWER BACK THAT INCREASED LATER IN THE DAY. HE FINISHED THE SHIFT AND WENT TO THE HOSPITAL ON THE WAY HOME. HE WORKED HIS REGULAR SCHEDULE/REGULAR JOB THE 29TH AND 30TH AND TOOK ANNUAL RE-TRAINING ON THE 31ST. HE STARTED MISSING WORK 8/2/04.