EE WAS RIPPING SURFACE ROCK W/D8 DOZER WHEN RIPPER CAUGHT THEN RELEASED CAUSING DOZER TO BUCK, SPRAINING EE'S UPPER BACK. EE DID NOT REPORT UNTIL 9-3-02 & WAS SENT TO DOCTOR. DR EXAMINED, X-RA Y NEGATIVE, PRESCRIPTION MEDICATION, RESTRICTED, RELEASED TO REGULAR DUTY TODAY.