INJURED STATED THAT ON 12-22-02 WHILE SHOVELING ON THE 2C BELT, HE FOUND A ROCK LAYING AGAINST THE STRUCTURE. WHILE ATTEMPTING TO MOVE THE ROCK HE FELT A PULL IN HIS LEFT BUTTOCK. INJURED CONT INUED WORKING . ON 1-10-03 INJURED REPORTED TO US THAT HIS LEFT BUTTOCK WAS HURTING. INJURED WENT TO THE DOCTOR AND RECEIVED MEDICATION. WENT BACK TO DR. NOT REPORTABLE UNTIL 1-10-03.