AN UNINTENTIONAL ROOF FALL OCCURRED ON THE MAIN NORTH TRACK AT 21 X CUT. THE FALL OCCURRED AT A 4 WAY INTERSECTION. THE FALL WAS 30 FT LONG X 20 FT WIDEX 8 FT HIGH. FALL OCCURRED DUE TO THE D ETERORATION OF THE IMMEDIATE ROOF. THE AREA WAS SUPPORTED BY 8 FT LONG POINT ANCHOR ROOF BOLTS EXPANDER SHELL & 2 FT OF GLUE. HENDER BLOCK AND WOODEN PLANK WE USED INJUCTION WITH THE ROOF BOLT