JACKLING, DANIEL COWAN

born Aug. 14, 1869, Appleton City, Mo., U.S. died March 13, 1956, San Francisco, Calif. American mining engineer and metallurgist who developed methods for the profitable exploitation of low-grade porphyry copper ores and thus revolutionized copper mining. A graduate of the Missouri School of Mines, Rolla, in 1892, Jackling taught chemistry and metallurgy there (189193) and then worked (189495) as a chemist and metallurgist in the Cripple Creek district of Colorado. While engaged in treating gold ores at Mercur, Utah, he was commissioned to make a report on a copper prospect at Bingham Canyon. His report led to the formation (1905) of the Utah Copper Company, for which he developed methods of exploiting ores yielding only 25 pounds of copper per ton (equivalent to 12.5 kilograms per 1,000 kilograms). Jackling was active in operating and executive positions in the Nevada Consolidated Copper Company; the Kennecott Copper Corporation, for which he directed western operations until his retirement in 1942; and the Mesabi Iron Company.