It would be difficult to overstate the importance of copper in the role of the economy of Arizona, where students used to learn about “The 5 C’s” — copper, cattle, cotton, citrus and climate.

Although copper has been mined around the world for more than 6,000 years, only during the past 125 years has it become an essential building block to an international economy.

The term “copper” is derived from the Latin word cuprum, a name applied to the island of Cyprus. The mines on Cyprus provided the ancient Romans copper with which to build their infrastructure.

Copper mining later flourished in Arabia around AD 800 and in Germany around AD 1556 with the publication of “De Re Metallica” by Georgius Agricola. His text provided an early description of copper processing, including the concentration, roasting, matting, reduction and refining of ore.

In 1845, the discovery of great deposits of native copper around Lake Superior in Michigan — and in later decades rich mines in Arizona, Montana, New Mexico, Nevada and Utah — enabled the United States to surpass Europe in copper production by the end of the 19th century.

Copper became the dominant mineral mined in Arizona in 1888 with a value of $5 million, a figure higher than the return on all other metals produced in the Territory that year.

In 1910, Arizona became the top copper producer in the nation with a production valued at almost $38 million, and it continues to be the top producer today with 814,000 tons produced in 2009.

Copper mines became more abundant in Arizona during the 20th century due to several factors, including the ability to exploit low-grade ore deposits (averaging less than one percent of copper) by the use of large-scale operations such as open-pit mining and the flotation process wherein copper minerals are separated from waste rock.

The use of the flotation process further expanded copper mines throughout Arizona.

Copper is reddish-brown, but when it reacts with oxygen in an environment involving water and carbon dioxide in moist air, it acquires a green patina.

The Statue of Liberty, covered with copper plates, appeared copper in color when it was dedicated in 1886. However, over the course of a century the plates were exposed to the elements and the statue took on a green hue.

Copper is both malleable and ductile and an excellent conductor of heat and electricity. It is corrosion-resistant and antimicrobial, destroying pathogens and allowing for the reduction of diseases.

The demand for copper in today’s high-tech world is great. It is used in the electrical, construction, communications and transportation industries, and in ordnance. Copper is also used as a bonding agent for metals including gold and silver.

Arizona produces an average of 65 percent of the copper in the United States. One of the greatest-producing mines in Arizona is Morenci, which produced 514 million pounds of copper — more than a third of the state total — in 2010.

Other large mining operations are Ray, Bagdad, Mission, Sierrita and Safford.

Demand for copper is projected to increase during the 21st century with the industrialization of China and India. Today the leading country in the world’s copper-mine production is Chile, with an output of nearly 5.3 million tons of copper in 2011.

Sources: “Minerals and Mining,” Arizona Geology Magazine (Nyal Niemuth, 2010); Bureau of Mines Bulletin No. 667 “Mineral Facts and Problems,” 1975; Bulletin No. 180 Mineral and Water Resources of Arizona, 1969; “Copper: The Science and Technology of the Metal, Its Alloys and Compounds (Allison Butts, 1954); “Chemical Elements From Carbon to Krypton,” Vol. 1 A-F (David E. Newton, 1999); “The Economic Impact of the Mining Industry on the State of Arizona — 2011,” prepared for the Arizona Mining Association by L. William Seidman Research Institute, W.P. Carey School of Business, Arizona State University; World Copper Factbook 2012.

William Ascarza is an archivist, historian and author of five books, including “Southeastern Arizona Mining Towns” and “Arizona-Sonora Desert Museum,” sold at Antigone Books, Cat Mountain Emporium, the Arizona-Sonora Desert Museum and the Arizona Geologic Survey’s Arizona Experience Store. Email him at