AN UNINTENTIONAL ROOF FALL WAS DISCOVERED ON D-3MAINS NO. 3 ENTRY 1 BLOCK OUTBY SPAD 4136. THE FALL WAS APPROX. 40' X 16' X 7' HIGH. THE FALL CONTAINED 5' RESIN TENSION BOLTS AND WAS DEVELOP ED AUGUST 1999. THIS FALL BLOCKED THE PRIMARY ESCAPEWAY FOR THE 001 UNIT. PERSONS WERE WITHDRAWNADDITIONAL SUPPORT INSTALLED AT THE BROWS AND A ESCAPEWAY WAS RE-ESTABLISHED WITH TIMBERS.