Employee was on a rubber bull. A low fuel pressure warning came on & smoke came from the engine. The bull was shut down & the fire system activated. Firehall was called & water trucks were dispatched. 10-15 mins of spraying, the fire was extinguished. The Master switch was shut off & scene was secured. MSHA was called at 7:58 The fire was out at 8:06. MSHA was called at 8:08