TWO EMPLOYEES WERE MOVING A FLETCHER ROOFBOLTER THROUGH A SET OF 5' DOUBLE DOORS WHEN THE HEAD OF THE BOLTER CAUGHT ONE OF THE DOORS. THEY WERE TRYING TO FREE THE DOOR WHEN VICTIM FELT A SHARP PAIN IN HIS LOWER BACK. HE FINISHED THE SHIFT & CONTINUED TO WORK UNTIL 6/24/03 WHEN HE SAW A DOCTOR & WAS DIAGNOSED WITH A MUSCLE STRAIN IN THE BACK.