AN UNEXPLAINED FALL OF ROOF MEASURING APPROX. 11' WIDE X 4' HIGH AND 12'LONG FELL ONTO RIPPERS OF MACHINE AS THEY WERE TRAMMING FROM THE FINISHED CUT OF THE #31 LIFT OF A 5 CUT PARTIAL PILLAR RECOVERY PLAN FOULING MACHINE. MACHINE WAS DISLODGED WITH ASSISTANCE OF ATTACHED UNIT. AREA WAS TIMBERED OFF AND MINING WAS CONTINUED.