A revolutionary development in American copper mining took place when mining engineer Daniel Cowan Jackling conceived of mining the huge but low-grade copper ore body at Bingham Canyon, Utah, using steam shovels in a big open pit. Steam shovels had previously been used in the iron mines of the Mesabi Range, in Minnesota, but had not been used in copper mining. Jackling incorporated the Utah Copper Company in 1903, and in 1906 began excavating. From the start, the Bingham Canyon Mine was one of the leading copper-producing mines in the world, and returned a good profit mining ore with less than two percent copper. Mining by open-pit model using large-scale mechanization was copied by other US mines, in Ely, Nevada (1908), Santa Rita, New Mexico (1910), and Ajo, Arizona (1917). The entire output of these mines was low-grade milling ore. The open-pit mining of porphyry copper deposits was adopted worldwide.