EMPLOYEE WAS LOADING BELT STRUCTURE INTO A SUPPLY CAR. WHEN HE TWISTED HIS BACK ABOUT 7:00 PM CONTINUED TO WORK THE REST OF THE SHIFT. EMPLOYEE NEVER SAID ANYTHING ABOUT IT TO HIS FOREMAN AT THE TIME OR AFTER THE SHIFT. IT WAS REPORTED TO ME AT 3:00 PM ON 9-13-01. HE HAS NOT REPORTED SINCE.