Mining Arizona's hidden treasure

Isabel Barton overlooks a mine on the Utah-Colorado border.

Isabel Barton overlooks a mine on the Utah-Colorado border.

College of Engineering

Arizona public university researchers are partnering with the State Mine Inspector and mining community to find new ways to reuse copper tailings, the waste rock left behind after mining the ore.  

It's estimated that the past century of mining has led to 17.5 billion tons of copper tailings, which is usually pulverized to the size of fine sand. 

With support from a $3.6 million Regents' Research Grant approved by the Arizona Board of Regents on Sept. 28, university researchers plan to assess the metal content from this waste rock in search of critical elements such as lithium, which are used in everything from cell phones to electric vehicles and pacemakers. This interdisciplinary project will draw on the expertise of a total of 13 faculty and staff in nine departments across all three Arizona public universities. 

"The extraordinary volumes of leftover rock from copper mining make reprocessing copper tailings a world-class challenge and opportunity for Arizona," said assistant professor Isabel Barton, from the Department of Mining and Geological Engineering in the College of Engineering. Barton is serving as principal investigator for the Regents' Research Grant.

"This large-scale interdisciplinary project represents a substantial first step toward making use of a massive, but undeveloped, potential resource," she added.  

Regents' Research Grants pair Arizona's public university researchers with government agencies and community organizations to address longstanding challenges in Arizona. Barton will draw on the expertise of 13 researchers in nine departments across all three Arizona public universities to complete the three-year project. 

"Leveraging researchers across disciplines and universities ensures our brightest minds work together to focus on the areas of greatest need in Arizona," said ABOR Chair-elect Cecilia Mata. "We are proud to fund critical research at ASU, NAU and UArizona that is working to strengthen the long-term prosperity, health and security of Arizona communities." 

Copper is one of the most economically important metals mined in Arizona, and the state continues to lead the nation in copper production. Researchers estimate the copper industry will add 200 million tons of copper tailings annually.  

"The large amounts of copper tailings in Arizona presents an opportunity for our state to reuse this left behind rock as a potential secondary source of metals and minerals that are critical to the economic and national security of the United States," said Arizona State Mine Inspector Paul Marsh. "Removing valuable and problematic metals and minerals from the tailings could also help reduce air and ground water contamination." 

This grant builds upon another Regents' Research Grant that is cataloging abandoned mines and creating a risk assessment. On Thursday, the board also approved two additional Regents' Research grants: 

  • Wastewater treatment and reuse: Researchers from the three state universities are partnering with the Arizona Department of Environmental Quality to find solutions to better test for harmful contaminants such as viruses and per-and polyfluoroalkyl substances, known as PFAS, in biosolids, the nutrient-rich byproduct of wastewater treatment. Arizona is one of nine states that permit biosolids to be used in agricultural land, parks and mining sites. ADEQ is asking researchers to further identify testing to ensure the safe reuse of these biosolids.
  • Effective environmental communications: Researchers at Arizona State University are partnering with ADEQ to study the psychology and data needed to increase compliance with the state's environmental laws and better communicate with residents and businesses. At the end of the three-year study, researchers will provide a "communications toolbox" that ADEQ can use to provide more effective communication and engagement with both regulated facilities and the public, achieve higher compliance rates and promote targeted action to ensure protection of public health and the environment.

A version of this article originally appeared on the Arizona Board of Regents website.