Editor’s note: This is the first in a two-part series on the Ajo mining district.
Located at an elevation of 1,750 feet on the western end of Pima County, the Ajo district is considered to be one of the oldest copper mining districts in the Southwest.
The iron- and copper-stained rocks of Copper Mountain drew prospectors in the 1850s who discovered high-grade copper ore.
The district is believed to have been the first worked by whites in the Southwest after Santa Rita, N.M. However, it was worked by the Spanish and later the Mexicans as early as 1750.
Several factors led to the increase of mining in the Ajo district. The initial factor was the arrival of the Southern Pacific Railroad on April 1, 1879, at Gila Bend, coming from Los Angeles. In addition, the advancement of electric power that same decade drew more demand for copper wires.
In 1900, John R. Boddie and Capt. Huie, along with several others, formed the Cornelia Copper Co. with the intention of working the mines at Ajo. The company and subsequently the mine were named for John Boddie’s first wife.
By 1909, after several years of exploration drilling, the Cornelia Copper Co. was reorganized as the New Cornelia Copper Co. The following year, the Calumet and Arizona Mining Co. conducted drilling of the Ajo deposit. Igneous rocks comprise most of the district and include andesite, basalt, lava and breccia.
John Campbell Greenway, a veteran of the Spanish-American War and a renowned mining engineer, made decisions that were pivotal to the success of mining operations in Ajo.
In 1911, preparations were made to determine the size of a copper-ore body in Ajo. A young geologist, Ira Joralemon, was in charge of the project sanctioned by Greenway. A total of 84 holes were diamond-drilled and proved that the ore body existed.
Next week: The Ajo district continues to grow and flourish.
Sources: Bulletin No. 169, The Mineral Industries of Arizona, Tucson, University of Arizona Press, 1962; Bulletin No. 180 Mineral and Water Resources of Arizona, Tucson, University of Arizona, 1969; James Gilluly (1946), The Ajo Mining District, Arizona, U.S. Geological Survey, Professional Paper 209, U.S. Government Printing Office; Joralemon, Ira B., 1973. Copper: The Encompassing Story of Mankind’s First Metal, Berkeley, Calif., Howell-North Books; Keith, Stanton B., Geologic Guidebook Three — Highways of Arizona: Arizona Highways 85, 86 and 386. Arizona Bureau of Mines Bulletin 183, Tucson, University of Arizona, revised 1974.
Email archivist and historian William Ascarza at email@example.com
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