A ROOF FALL WAS DISCOVERED AT ABOUT 0600 BY THE PRESHIFT EXAMINER. AN INTERSECTION FELL ABOVE THE ANCHORAGE ZONE IN SECTION 3 RIGHT, ENTRY #6, XCUT 13. VENTILATION & ESCAPEWAYS WERE NOT AFFECT ED. AZTEC, NM FIELD OFFICE WAS NOTIFIED AT 0655, 9-21-01.