EMPLOYEE WAS BOLTING IN PANEL SB08 IN RM 3 LEFT, HE HAD JUST FINISHED A ROW OF BOLTS AND WAS POSITIONING THE BOLTER FOR THE FIRST BOLT OF THE NEXT ROW WHEN A SLAB FELL OUT OF THE BACK AND STRU CK HIM ON THE RT FOREARM LEFT SHOULDER AND HE SAID HIS LOWER BACK WAS SORE.