AN UNINTENTIONAL ROOF FALL WAS DISCOVERED ON 8-1-01 IN THE #1 HEADING (RETURN) AT BREAK #121. FALL WAS APPROX 18' WIDE BY 20' LONG BY 10' HIGH. NO INJURIES, NO EQUIPMENT CAUGHT, VENTILATION WAS NOT INTERRUPTED. THE AREA HAD BEEN BOLTED WITH 6' TENSION REBAR BOLTS AND CABLE BOLTS IN THE INTERSECTION.