A UNITENTIONAL ROOF FALL HAS OCCURED INT HE #3 UNIT INT HE #2 ENTRY THE FALL BEGAN AT SURVEY STATION 17897 AND FELL 640 FT X 20 FT X 10 FT. THE FALL WENT RIGHT AND LEFT FOR 240 FT AND THEN DOW N THE #1 ENTRY FOR AN ADDITIONAL 320 FT AND STOPPED AT 55#17610. THERE WERE NO INJURIES OR PROPERTY DAMAGE REPORTED.