A FALL OF ROOF OCCURRED AT INTERSECTION BETWEEN 11 & 12 BUTT ON THE TRAM ROAD TO 17 BUTT IN THE OLD G-MAINS ENTRIES AT SPAD STATION 4421. FALL WAS 16 FT WIDE X 40 FT LONG X 6-7 FT HIGH. NO EQU IPMENT INVOLVED AND NO INJURIES. AREA WAS SUPPORTED TO PLAN WITH 6 FT TORQUE TENSION BOLTS.