A ROOF FALL WAS DISCOVERED IN NO. 1 ENTRY(RETURN)3-WAY INTERSECTION AT SURVEY STATION NO. 4486. THE FALL IS APPROX 50 FT LONG X 14 FT WIDE AND CONTAINED 6'5/8"" BOLTS & TIMBERS. THE APPROACHS W ERE DANGERED OFF AND THE RETURN AIRWAY WAS REROUTED WITH CONSTRUCTION OF 5 STOPPINGS. THIS AREA ON D-6 PANEL WAS DEVELOPED 3/2000.