Making Charcoal for Fuel
As iron production expanded, so did the need for fuel. In the early days of iron, all furnaces and forges were powered by charcoal made in kilns with wood cut from the forests within economic hauling distance. According to Patrick Ferrell, an iron historian and former employee of Republic Steel, one acre of forest land yielded cordwood for charcoal sufficient to smelt 14 tons of ore. “This source of fuel became costly as production increased and forests were cleared,” write Farrell in his book Through the Light Hole.
Production of charcoal was a major operation. Crews of woodcutters cut trees, limbed them, cut the logs to the proper length, and hauled them to burning areas or kilns. Farrell describes the lengthy process, which would have been an around-the-clock operation: “The logs were stacked upright in a circular area and shaped like a cone, with an opening left in the top; the cone was then covered with dirt. Brambles and chips were dropped down the center of the cone and ignited. Where necessary for proper draft, small openings were made in the sides of the cone. A week or more was required to properly char the cone of wood, and the burning required close attention day and night. Wood that was cut in cold winter weather contained less sap, dried harder, and made the best charcoal. When the burning was completed the cooled charcoal was delivered to the coaling area at the furnace. Hauling distance increased as the forests were stripped near the furnaces and the charcoal burning operations were moved to the source of wood supply. In some instances, coaling kilns were made at the furnaces and wood was delivered from the forest to the kilns.”