A FALL OCCURRED IN THE FACE AREA OF #1 ROOM OFF B-MAINS AT 12+00, 80' LEFT OF STATION 403. THE FACE WAS TURNED INBY TO THE RIGHT FOR A 20' CUT. THE ROOF STARTED WORKING AND THE FALL OCCURRED A BOUT 90 MINUTES LATER. IT STARTED AT THE FACE AND TOOK THE INTERSECTION WITH IT. THE FALL WAS 20' WIDE AND ABOUT 40' LONG, 5 1/2' HIGH.