This open pit mine in southeast Arizona is so large that it swallows up U.S. Route 191. Travelers driving south along the highway will be surprised to emerge from upland pine forests into a desolate, Martian-like landscape. This is the Morenci Mine, one of the largest copper mines in the world.

With an annual production of between 700 and 850 million pounds of copper, the Morenci Mine is the largest copper mine in Arizona. It was first explored in the 1860s by gold prospectors, but wilier miners smelt a better opportunity in the mountainous atmosphere. By 1881, the Phelps Dodge Company began operations that would rapidly expand and make Arizona famous as the Copper State.

For over 100 years, the copper mining industry weathered geological challenges and wild market fluctuations, but in the early 1980s, the Morenci mine was the center of a desperate human drama. As the worldwide recession deepened, Phelps Dodge invalidated collective bargaining with the mining unions and thus began the Great Arizona Copper Strike, lasting from 1983 to 1986. At one point, the Arizona governor called up 350 National Guard troops, 450 state troopers, and 160 SWAT sharpshooters to protect the gates to the mine. The political, economic, and social damage done to the surrounding communities continues to be felt today, and are recounted by Anna Ochoa O’Leary in a new book, Mexican Workers and the Making of Arizona.

Today, the mine employs more than 3,000 people and continues to define Arizona’s identity in addition to being loaded with history.