AN UNINTENTIONAL ROOF FALL WAS DISCOVERED AT SURVEY STATION 352 OF NORTH MAINS INTAKE ESCAPEWAY THE FALL WAS DANGERED OFF AND ADDITIONAL SUPPORTS INSTALLED. 4 LEFT 1 NORTH PRIMARY ESCAPEWAY WA S EFFECTED UNTIL THE FALL WAS TIMBERED. AREA OF FALL APPROX. 20' WIDE, 35' LONG, 10' HIGH.