SPARKS CREATED AS A SEMITRAILER TRUCK SLID ON ITS SIDE IGNITED A GRASS FIRE ON THE WEST SIDE OF I-15 JUST SOUTH OF OGDEN'S WILSON LANE ON-RAMP ABOUT 8:30 P.M. ON WEDNESDAY. UTAH HIGHWAY PATROL TROOPER AL BIGBY SAID THE TRUCK, WHICH WAS CARRYING A 22-TON PIECE OF INDUSTRIAL EQUIPMENT, FLIPPED ON ITS SIDE WHEN THE METAL STRUCTURE OF THE TRAILER BEGAN TO FAIL AND THE LOAD SHIFTED. THE TRUCK SLID ABOUT 310 FEET BEFORE STOPPING ON THE WEST EDGE OF THE PAVEMENT. THE FIRE BURNED ABOUT TWO ACRES OF FIELD STUBBLE AND FORCED THE CLOSURE OF THE SOUTHBOUND LANES OF I-15 FOR ABOUT 30 MINUTES. THE DRIVER, MARK L. PETERSON, 36, KIMBERLY, IDAHO, WAS NOT INJURED.