Daniel Cowan Jackling was founder of the Utah Copper Company and is credited with pioneering and developing the method of processing of low-grade porphyry copper ores. His ore-processing methods have been particularly associated with the development of the Bingham Canyon open-pit copper mine. Jackling was born on 14 August 1869 near Appleton, Bates County, Missouri. He was orphaned by age two, and spent much of his childhood living with different relatives on Missouri farms. Jackling was educated at the State Normal School at Warrensburg, Missouri, and at the Missouri School of Mines at Rolla. He graduated from the latter institution in 1892 with a B.S. degree, and he spent the next year at his alma mater as assistant professor of chemistry and metallurgy.

During the next three years (1893-96), Jackling became involved with mining on a firsthand basis, particularly at Cripple Creek, Colorado. During this period, he worked as a miner, an assayer, a mill hand, and a metallurgist. In 1896 he moved to Mercur, Utah, where he became construction and metallurgical superintendent of the Golden Gate mill, which was owned and operated by Joseph R. DeLamar and Enos Wall. Wall had claims to extensive mining property in Bingham Canyon, and in 1898 DeLamar asked Jackling and Robert C. Gemmell to make an extensive examination of the Wall copper property at Bingham. Gemmell directed the sampling and geological work while Jackling directed the assaying and mill tests in the old Rogers Mill at Bingham. The Jackling-Gemmell report was dated 18 September 1898 and urged mass mining and milling of the low-grade copper ore found at Bingham. DeLamar opted not to be involved, but in 1903 the Utah Copper Company was organized with Charles MacNeill, one of Jackling's former Colorado mining associates, as president, Enos Wall as vice-president, and Jackling as general manager.

The Jackling-Gremmell plan, which was put into operation by both the Utah Copper Company and the Boston Consolidated Company at Bingham, included stripping the overburden or waste, then in open-pit mining fashion loading the low-grade ore (often less than 2 percent copper) into railroad cars with steam shovels, and transporting the ore to concentrating mills built on the north slope of the Oquirrh Mountains. One of Jackling's first responsibilities was to oversee the construction of a mill at Copperton, which was used to demonstrate the validity of his copper-mining theories, and later he directed the building of the Magna concentrator, which was begun early in 1906. He also was successful in obtaining additional financial backing for Utah Copper from the Guggenheim family. In 1910, at Jackling's urging, the Boston Consolidated Company with its mining interests at Bingham and its Arthur milling facilities located west of the Magna Mill merged with and became part of the Utah Copper Company. By midway through the twentieth century, more than 60 percent of the world's copper production resulted from Jackling's development of low-grade ore processing.

During the first four decades of the twentieth century, Jackling had his hand in most copper companies in the American West as a manager and/or director. During World War I, Jackling served as director of government explosives plants, and for his outstanding wartime efforts he was awarded the Distinguished Service Medal by President Woodrow Wilson. In 1926 Jackling was awarded the Gold Medal Award of the Mining and Metallurgical Society of America, and in 1930 the American Institute of Mining and Metallurgical Engineers honored him with the William Lawrence Saunders Gold Medal of "achievement in initiating mass production of copper from low-grade ore through application of engineering principles." In 1940 Jackling was given the Washington Award of the Western Society of engineers for "pioneering in large-scale mining and treatment of low-grade copper ores, releasing vast resources from formerly worthless despots."

Jackling moved from Salt Lake City to San Francisco in 1915, but continued to travel to his many areas of mining interest in private railroad car or in his yacht, the Cyprus. A larger than life copper statue of Jackling sculpted by Avard Fairbanks honors the copper giant and has stood in the rotunda of the Utah State Capitol Building since 1954. Jackling married Jeanne Beatrice Sullivan in Cripple Creek during his mining activities there and, following her death in 1914, he married Virginia Jolliff of San Francisco. He died on 13 March 1956 at his home at Woodside, California.