SOMETIME BETWEEN 11:10 PM AND 11:30 PM, THE LEFT REAR TIRE ON A SCRAPER CAUGHT ON FIRE. THE SCRAPER HAD BEEN USED THE PREVIOUS SHIFT AND PARKED AT 10:45 PM WITH A FLAT TIRE. THE FIRE WAS PUT O UT IN 30 MIN, BUT RE-IGNITED PERIODICALLY UNTIL WATER TRUCKS COOLED THE TIRE DOWN AND GUEL WAS REMOVED PREVENTING DRIPPING FROM A BURNED LINE.