DRAGLINE #80 WAS PERFORMING NORMAL OPERATION AT THE NORTH END OF H-PIT. AT APPROXIMATELY 19:30 PM THE MG SETS TRIPPED. THE DRAGLINE OPERATOR INVESTIGATED THE AREA AND DISCOVERED SMOKE AND HEAR D ARCING ACCOMPANIED BY FIRE. THE EMERGENCY PLANWAS ACTIVATED & THE EQUIPMENT STABILIZED BY APPROX. 21:00 PM. DAMAGE IS ELECTRICAL WITH ESTIMATED 6 WEEKS DOWNTIME.