History

A Legacy of Copper in Arizona

Arizona has a diverse cultural history, especially in the Copper Triangle. For more than a century, mining and ranching have played an important role in shaping local communities

Copper is a cornerstone of Arizona’s history and economy. Since 1910, the state has been the nation’s leading producer of copper. Today, approximately 68 percent of the copper produced in the United States comes from Arizona. The copper star at the center of the Arizona flag reflects the industry’s lasting importance to the state.

A Century of Mining in the Copper Triangle

Mining has long influenced the landscape and communities of the Copper Triangle. While mining brings change, it also carries responsibility. Resolution Copper is committed to protecting the surrounding land during operations and through closure and reclamation.

Respect for cultural and historical significance is built into how Resolution Copper plans the project. Learn more about how we protect cultural heritage.

The Pioneer Mining District traces its roots to the mid‑1800s. In 1875, the Silver King Mine began producing silver, marking the start of large‑scale mining in the area.

In 1912, the Magma Copper Company’s underground mine began operations in Superior. For more than 80 years, the mine played a central role in building the town and shaping the region’s mining identity, operating until the mid‑1990s.

After the mine closed, interest in developing a deep copper deposit near Superior, while reusing the already disturbed Magma Mine site, kept the property active. In 2004, Resolution Copper Mining assumed control of the site.

Arizona has been mining country for generations. By placing Arizona resources and workers at the center of this project, Resolution Copper builds on that history while supporting the state’s role in domestic mineral production.