Before 1876, the economics of copper mining in Arizona were impossible. The metal had value, but shipping it from the desert interior by wagon cost more than it was worth. Silver and gold could justify the expense; copper could not. When the Southern Pacific's rails finally reached southern Arizona, the equation reversed. Suddenly, ore that had sat worthless in the ground became viable. Mining camps that had flickered in and out of existence found permanence. Bisbee, Clifton, Morenci, Globe, these names that would define Arizona's copper belt emerged as the railroad opened markets to the east. The copper industry that would dominate Arizona for the next century was born not in a mine shaft but in a railroad boardroom.

For decades, all copper mining meant tunneling. Miners descended into darkness, following veins of ore through narrow passages, extracting what they could carry. Then Utah's Bingham Canyon mine proved that massive low-grade deposits could be profitably extracted from open pits, removing entire mountains layer by layer. Arizona applied this technique to its porphyry copper deposits starting at Ajo in 1917, where the New Cornelia mine became the state's first large open-pit operation. The Lavender Pit at Bisbee, operating from 1951 to 1974, became one of the largest open-pit copper mines in the world. These operations transformed the landscape on a scale visible from space, terraced bowls carved into the earth like inverted ziggurats.

Each district has its own story. At Jerome, the United Verde mine exhausted its rich oxidized ores by 1884 and closed, only to be bought by Montana copper baron William A. Clark in 1888 and reopened with new methods. At Ajo, Spaniards had extracted copper on a small scale since 1750, but the desert location made large-scale mining impossible until the New Cornelia open pit arrived. The Clifton-Morenci district, discovered by prospectors from Silver City, New Mexico in 1872, waited for a railroad connection in 1884 before low-grade ore processing became economical. Globe started as a silver camp in 1874, converted to copper in 1878 when the silver played out. The White Mesa district on Navajo land was mined briefly by Mormon settlers, then in 1917, then 1939-1941, producing a modest 550,000 pounds.

Copper was never the only prize. Arizona's mines produced gold and silver as byproducts, an ironic reversal of the early prospectors who had ignored copper while seeking precious metals. The Clifton-Morenci district alone recovered 2.79 million ounces of gold and 102 million ounces of silver alongside its copper. Molybdenum extraction made Arizona the nation's second-largest producer of that metal. The mines also yielded 324 million pounds of lead, 355 million pounds of zinc, and 28 million pounds of manganese from Clifton-Morenci. When you dig for copper in Arizona, you dig up an entire periodic table.

Today, Arizona copper mining is dominated by corporate giants operating on massive scales. Freeport-McMoRan runs five of the state's leading mines; ASARCO operates three more. The Resolution Copper deposit in Pinal County could become the largest copper mine in Arizona's history, but as of recent years, it remains stalled in a complex land swap negotiation with the federal government. Open-pit operations south of Tucson are visible in astronaut photographs, their terraced walls recording each generation's extraction. From the Spanish prospectors who noted copper minerals but moved on, to the railroad executives who made extraction profitable, to the corporate miners who now move mountains with industrial efficiency, Arizona copper has shaped the state's economy, landscape, and identity for a century and a half.