Center Furnace, sometimes called Hematite, was built by 1852 by Daniel Hillman 2 1/2 mi. west; it stood 35 ft. high and 10 ft. across inside at its widest point. It operated, though not continuously, until 1912, burning charcoal fuel, and its air blast was powered by steam. In 46 weeks of 1856, it produced 2,139 1/2 tons of pig iron, most of it shipped by steamboat to fabricators. Kentucky had been a major iron producer since 1791, ranking 3rd in the US in the 1830s and 11th in 1965. Charcoal timber, native ore, and limestone supplied numerous furnaces in the Hanging Rock, Red River, Between Rivers, Rolling Fork, and Green River regions, where pig iron, utensils, and munitions were made. The charcoal-furnace era ended in the 1880s with depletion of ore and timber and the adoption of modern methods.