A ROOF FALL WAS DISCOVERED BY THE SECOND SHIFT PRESHIFT EXAMINER ON THE NO.2 UNIT, 20TH EAST,#3ENTRY, SPAD 85+78.8. THE FALL OCCURRED IN THE PILLAR LINE AND THROUGH AN INTERSECTION. IT MEASUR ED APPROX., 100'X 17'X 8'. IT WAS IMPOSSIBLE TO DETERMINE IF THE FALL ORIGINATED IN THE PILLAR LINE OR IN AN INTERSECTION. IT FELL ON THE UNIT BELT TAILPIECE AND RATIO FEEDER.