UNINTENTIONAL . AN 80' X 18' X 4-5' PIECE OF ROOF FELL. THE FALL WAS IN AN OLD AIRWAY USED TO VENTILATE EP AREAS ONLY. FALL WILL NOT BE CLEANED UP, FALL WILL BE TIMBERED ACROSS FOR PASSAGE OF FIREBOSS. APPROACHES TO FALL HAVE BEEN DANGERED OFF. ROOF HAD 4"" FULLY GROUTED RESIN BOLTS USED.