AN UNINTENTIONAL ROOF FALL OCCURED ON THE UNIT 3WORKING SECTION ON THE RIGHT SIDE OF THE UNIT INROOM 1 AT THE +165 FT MARK. THE AREA HAD A SLIP PRESENT & THE AREA HAD BEEN SUPPORTED BY 5 & 6 FT CONVENTIONAL TYPE ROOF BOLTS. THE FALL WILL NOT BE CLEANED UP & ALL APPROACHES HAVE BEEN TIMBERED OFF & DANGER SIGNS POSTED. THE FALL MEASURED 5' HIGH, 16' WIDE & 20' LONG