A ROOF FALL WAS DISCOVERED MEASURING 8' HIGH X20' WIDE X 16' LONG AND MIDWAY OF INTERSECTION. IT TRAVELED 6'-8' INBY CORNER OF INTERSECTION 1 BREAK INBY SS#2451 #3 ENTRY. EQUIPMEN WAS NOT INVO LVED. VENTILATION WAS NOT DISTRUBED. NO INJURY OCCURRED. THE FALL WILL NOT BE CLEANED UP.