UNINTENTIONAL ROOF FALL. 6-NORTH - CROSS-CUT BETWEEN #5 & #6 ENTRY, AT #34 INTERSECTION OFF THE CONVEYOR BELT ENTRY. FALL APPROX 16' LONG, 15' WIDE & UP TO 4'-5' HIGH (ABOVE THE 4' ROOF BOLTS). AREA BEGAN FALLING OUT AROUND BOLTS ON FEB 2, 2005 BUT NOW BECAME REPORTABLE ON 2-18-05. NO PASSAGE OR VENTILATION AFFECTED.