A FRICTIONAL IGNITION OCCURRED AT THE FACE OF THE #4 ENTRY WHICH HAD BEEN MINED IN 35 FEET IN THE F-12 SECTION. THE FLAMES FROM THE IGNITION LASTED APPROXIMATELY ONE MINUTE AND WERE EXTINGUISHED WITH THE WASHDOWN HOSE AND 1 1/4 INCH WATERLINE. THERE WERE NO INJURIES OR DAMAGE TO EQUIPMENT.