Editor’s note: This is the second in a two-part series on the Ajo mining district. To read the first part of this series go online to tinyurl.com/ajomine

John Campbell Greenway acquired the New Cornelia Copper Co. for the Calumet and Arizona Mining Co. from John Boddie in 1913. A concerted effort was made to discover the main ore body over the next several years.

More than 25,000 feet of drilling was undertaken to confirm the existence of the 30 million tons of ore that lay beneath the surface. A large leaching plant capable of processing 5,000 tons of ore per day was established at the site by 1917.

Greenway persuaded the Calumet and Arizona Mining Co.’s directors to build the plant, which was capable of removing the oxide overburden and thus securing access to the sulfide ore deposit.

That same year the New Cornelia Copper Co. started open-pit mine operations in Ajo, making it the earliest steam-shovel enterprise in Arizona history.

It was during this time that Ajo became one of Arizona’s wealthiest mining camps. World War I boosted copper prices to 25 cents a pound, ensuring a company profit while covering operating expenses. The town of New Cornelia north of Ajo reached a population of more than 5,000.

Between the 1880s up to 1917 total copper production at Ajo amounted to less than 1.7 million pounds a year. From 1917 to 1934, production rose to a total of 805 million pounds.

In 1924 a concentrator was built at Ajo to treat the sulfide ore mined at New Cornelia.

By the late 1920s, the Calumet and Arizona Mining Co. was in dire financial straits because of its lack of capital to develop and operate its ore reserves. On Oct. 31, 1931 it merged with the Phelps Dodge Corp., becoming the New Cornelia Division of Phelps Dodge.

A standard gauge railroad, the Tucson, Cornelia & Gila Bend Railroad owned by the Phelps Dodge Corp., connected Ajo with the main line of the Southern Pacific Railroad at Gila Bend.

At one point in its history, the New Cornelia Mine was the fourth-largest copper-producing mine in the United States; its plant had a capacity of treating more than 31,000 tons of ore daily.

Ajo was a company town, with a main center plaza patterned after the Spanish colonial revival style.

The original town of Ajo was relocated, after being destroyed in a fire in the early 1910s, to its present location. The open-pit mine remains, of course, at its original location.

The settlements of Clarkstown or Clarkston east of Ajo and Gibson north of Ajo were formed during the 1910s by people who objected to Ajo’s company town status, where residents relied on the mining company for everything from food to schools and churches.

Gibson unsuccessfully attempted to change its name in 1917 to Woodrow after President Woodrow Wilson. However, its post office settled on the inversion of the name Woodrow, calling itself “Rowood.”

Clarkstown was later abandoned with the expansion of the open pit and Gibson was absorbed, becoming the northern suburb of Ajo.

By the 1960s, Ajo’s population reached more than 7,000 while the mine employed more than 1,000 workers. The mine itself produced copper until it closed Aug. 12, 1984, with the smelter closing the following year because of the low price of copper.

Today the New Cornelia pit, owned by Freeport-McMoran Gold and Silver Inc., is more than 850-feet deep and more than a mile wide. It bears testimony to Ajo’s significant contribution to Arizona’s mining history.

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 mining@azstarnet.com