A ROOF FALL MEASURING 80' LENGTH, 20'WIDE AND 5.5' THICK WAS DISCOVERED IN THE NO.1 RETURN ENTRY. THE ROOF FAILED DUE TO UNDETECTABLE SUBNORMAL CONDITIONS LAYERED SHALE ABOVE THE 48"" RESIN ROO F BOLTS. THE AREA WAS DEVELOPED JUNE 2003. THE FALL DID NOT AFFECT VENTILATION OR SAFE PASSAGE. THE PERIMETER OF THE FALL WAS RESUPPORTED BY 2 ROWS OF TEMPORARY SUPPORTS AND BARRICADED.