Empire Furnace stood one mile west. Built in 1843 by Thomas Tennessee Watson, it was a brick stack with a maximum inner diameter of 9 1/2 feet and a height of 35 feet. It burned charcoal fuel, and its air blast was powered by steam. In 45 weeks of 1856, it made 1836 tons of pig iron. Operations transferred to Center Furnace in 1861 because of floods and Civil War military actions. Kentucky had been a major iron producer since 1791, ranking third in the United States in the 1830s and eleventh in 1965. Charcoal timber, native ore, and limestone supplied material for numerous furnaces making pig iron, utensils, and munitions in the Hanging Rock, Red River, Between Rivers, Rolling Fork, and Green River regions. The charcoal-furnace era ended in the 1880s with depletion of ore and timber and use of modern methods.