AN UNINTENTIONAL ROOF FALL OCCURRED IN X-CUT 17, ENTRY #5 OF THE 1ST NORTH SUB-MAINS, ON THE 2ND WEST CONVEYOR BELT. THE FALL WAS IMMEDIATELY REPORTED TO THE MSHA FIELD OFFICE AND WAS INVESTIGATED BY THE OFFICE. THE FALL MEASURED 30'W x 40'L x 5'H. THE FALL WAS IN AN AREA BOLTED WITH 5' BOLTS PRIOR TO OPERATORS CHANGE IN ROOF CONTROL PLAN TO 6' BOLTS.