ROOF FALL OCCURRED ON THE #1 PORTAL BOTTOM ON THE #3 ENTRY SUPPLY TRACK. FALL OCCURRED AT 3+05 FEET. FALL WAS 50' LONG X 20' WIDE X 8' HIGH. AREA WAS MINED IN SEPT., 1971. FALL OCCURRED DUE TO THE DETERIORATION OF THE IMMEDIATE ROOF. AREA WAS SUPPORTED WITH 8' AND 10' CONVENTIONAL BOLTS & ALSO TRUSS BOLTS. FALL BLOCKED PASSAGE OF MATERIAL ON THE TRACK.