Since 1863, when prospector Jacob Waltz laid claim to a gold in patch of Arizona desert just 60 miles east of the burgeoning city of Phoenix, the Pioneer Mining District has been at the heart of the state’s mining industry.

While stories of Waltz’s claim continue to draw people searching for his legendary “Lost Dutchman’s Mine,” mining in the district began in earnest in 1875, when the King Mine began pulling silver out of the ground.

In 1912, the Magma Copper Mine started up, an operation that continued through the early 1990s, built the nearby town of Superior and came to define the Pioneer District and its rich stores of copper.

Today, the Resolution Copper team is cleaning up this historic mining site – work that is winning awards from environmental groups – and creating a plan to safely develop copper that lies nearly a mile beneath the surface of the original Magma Mine. Simple timeline:

  • 1863: Copper is discovered 60 miles outside Phoenix in an area that will become the Pioneer Mining District
  • 1875: The district’s first mine, Silver King, begins operating
  • 1887: The Silver Queen Mine begins producing copper
  • 1912: The Magma Mine starts up
  • 1995: The Magma Mine stops operations
  • 1995: The Resolution copper deposit is discovered
  • 2001-2003: Exploration of the Resolution project begins
  • 2005: Resolution begins studies to develop the proposed mine
  • 2007: Resolution begins pulling water out of the historic mine, treating it, testing it and transporting it to Arizona farmers
  • 2014: Resolution submits a plan of operations to regulators, beginning the process to permit the proposed mine


Arizona Mining History