EE WAS REMOVING ROCK OFF SCALPING SCREEN AND TWISTED HIS BACK WHILE SHOVELING ROCK. ADVISED SUPERVISOR THAT THIS WAS A BACK INJURY THAT HE HAD BEFORE HIS EMPLOY THAT ACTED UP WHEN JUST GETTING IN HIS CAR AT TIMES. AT TIME OF INJURY HE REFUSED MEDICAL TREATMENT. AT 3 PM HE ADVISED EE HE NEEDED TO SEE A DOCTOR.