A ROOF FALL WAS DISCOVERED IN THE NO.3 NEUTRAL ENTRY APPROX 1200'-1300' OUT BY THE ACTIVE SECTION. THE FALL MEASURED APPROX 20' L BY 20' W BY 3-3.5' THICK AND OCCURRED IN THE INTERSECTION AT SURVEY STATION NO. 284. THE AREA HAD BEEN SUPPORTED WITH 36"" MECHANICAL ROOF BOLTS WHEN THE AREA WAS DEVELOPED.