SMOKE WAS OBSERVED ORIGINATING FROM THE JOY UNDERCUTTER IN THE SALT, UG MINE. MINE SUPERVISOR IMMEDIATELY REMOVED POWER FROM MACHINE & MANUALLY DEPLOYED THE UNDERCUTTER'S KIDDE DRY CHEMICAL FI RE SUPPRESSION SYSTEM. THE MINE WAS EVACUATED & MSHA WAS NOTIFIED. THE MINE RESCUE TEAM WAS ACTIVATED AND PERMISSION RECEIVED FROM MSHA TO SEND IN TEAM TO INVESTIGATE FIRE. FULLY CONTAINED.