A METHANE IGNITION OCCURRED IN THE PRODUCTION SHAFT DUE TO A SPARK OR SLAG FROM A CUTTING TORCH. THE WORK WITH THE CUTTING TORCH WAS ON THE UPPER DECK OF THE PROD SHAFT HEAD FRAME, APPROX 650' ABOVE WHERE THE FLAME WAS DISCOVERED IN THE SHAFT. THE FLAME WAS APPROX 6"" LONG COMING OUT OF THE SHAFT WALL & WAS EXTINGUISHED BY A FIRE EXTINGUISHER. NO INJURIES OR EQUIP DAMAGE.