At an abandoned mine near Prescott, Arizona, Arizona State University researchers are testing ways to turn one of mining’s biggest environmental liabilities into a potential resource.
The project is led by Hamed Khodadadi Tirkolaei, an assistant professor of civil, environmental and sustainable engineering in the School of Sustainable Engineering and the Built Environment, part of the Ira A. Fulton Schools of Engineering at ASU. He and his team are collaborating with ASU Regents Professor Ed Kavazanjian, Assistant Professor Emmanuel Salifu and Professor Elham Fini, to develop nature-inspired bio-based methods to stabilize mine waste, reduce environmental contamination and recover critical minerals from waste and unconventional sources.
The work is part of the ASU Mining Innovation Initiative, which brings together researchers from several disciplines to help strengthen domestic critical mineral production, reduce environmental impacts and train the next generation of mining engineers.
One example is the team’s work at the Cash Mine site, where they used an enzyme-based treatment to stabilize mining waste and reduce erosion that could carry contaminants into nearby waterways. The project is supported by the Arizona Department of Environmental Quality, or ADEQ.
“By using an enzyme-based process to form natural mineral bonds within the soil, we can create a protective crust that helps limit erosion and dust generation while avoiding more chemically intensive treatments,” says Khodadadi Tirkolaei, who leads the ASU Mining Innovation Initiative.
The process can immobilize environmentally harmful substances, preventing them from reaching nearby rivers.
“The treatment solution can be prepared on site and implemented without the need for specialized equipment or heavy machinery, making it readily deployable in remote areas, including many abandoned mine sites, where conventional solutions may be difficult or impractical to implement,” says Khodadadi Tirkolaei, who is also a senior global futures scientist with the ASU Julie Ann Wrigley Global Futures Laboratory. “We have also developed a plant-based biopolymer technology that can be used in situations where enzyme-based treatment may be limited, such as mine wastes with high concentrations of the heavy metals that could suppress enzyme activity.”
Advancing critical mineral production sustainably
Across the School of Sustainable Engineering and the Built Environment, researchers are exploring ways to advance responsible critical-mineral production while reducing environmental impacts and strengthening domestic supply chains.
Recovering critical minerals from waste is a key focus for several researchers.
Assistant Professor Dwarak Ravikumar is using artificial intelligence, or AI, to enhance the recovery and reuse of materials from discarded solar photovoltaic panels and LED lighting products. His work focuses on circular economy approaches that help recover valuable materials.
“This work is vital, as significant quantities of critical minerals embedded in commercially valuable products are currently landfilled at the end of their lifespans,” Ravikumar says. “Implementing circular economy approaches can help not only to reduce our reliance on critical mineral imports but also increase economic activity and create jobs.”
Matthew Fraser, a professor of environmental engineering and associate director of the school, is working with Pierre Herckes, a professor in ASU’s School of Molecular Sciences, to study whether mine tailings could become a new source of critical minerals.
“These tailings — produced in mining for copper — have been viewed as an environmental liability,” Fraser says. “We are working to quantify the critical minerals that could potentially be extracted from these tailings to turn a liability into a resource.”
Crystal Davis is an analytical and environmental chemistry doctoral student in the School of Molecular Sciences at ASU and works with Fraser and Herkes on the project.
She and other ASU researchers were invited to showcase this work during the Arizona Mining Association’s Mining Day at the Capitol, where researchers introduced students and policymakers to emerging approaches for recovering critical minerals from mine waste. The team is doing preliminary experiments to test several ways that industry could recover those critical minerals, Davis says.
ASU Regents Professor of Environmental Engineering Bruce Rittmann is exploring biotechnology approaches to recover critical minerals from water generated through mining, ore processing and recycling. His team uses a Membrane Biofilm Reactor, or MBfR, to transform dissolved mineral ions into nanoparticles that can be recovered and reused.
Inside the reactor, bacteria transform dissolved minerals, including lithium, copper, gold and rare earth elements, into nanoparticles that can be harvested from the biofilm and processed for reuse.
“Periodically harvesting some of the biofilm recovers the valuable critical minerals in easy-to-process forms,” says Rittmann, who also serves as director of the Swette Center for Environmental Biotechnology, part of the ASU Biodesign Institute.
Fulton Professor of Structural Materials Narayanan Neithalath is researching how mine waste and industrial byproducts can be safely incorporated into construction materials. His work focuses on how the chemistry, microstructure and performance of cementitious systems could be enhanced while lowering the carbon footprint of infrastructure materials.
As attention to the supply chain of critical minerals grows, this work becomes even more important because it helps transform mining byproducts into valuable construction resources while supporting more sustainable materials production, Neithalath says.
Assistant Professor Matthew Landsman is in the early stages of work focusing on separating critical minerals from untapped natural resources and human-generated waste streams, including e-waste and industrial wastewater, while also understanding their fate in natural and engineered systems.
“By developing new organic-inorganic materials, such as selective membranes and sorbents, my group’s work will support greater circularity of critical minerals, minimize environmental impacts and strengthen long-term domestic resource resilience,” says Landsman, who is also an affiliate faculty member in the ASU Biodesign Institute’s Center for Sustainable Macromolecular Materials and Manufacturing.
Khodadadi Tirkolaei is also investigating using enzyme-induced carbonate precipitation to refine geothermal brines and enhance lithium recovery. Unlike conventional chemical softening methods, this process does not add sodium to the solution, since elevated sodium concentrations can make lithium recovery more difficult and less efficient.
Together, these research efforts reflect the School of Sustainable Engineering and the Built Environment’s broader focus on developing more sustainable technologies for waste management, environmental protection and critical mineral recovery across Arizona’s mining sector and the broader U.S. critical mineral supply chain.
Building industry partnerships
Mining professionals and companies have helped shape the ASU Mining Innovation Initiative by identifying needs in research, sustainability and workforce development.
Industry partners have connected with the initiative through lab visits, monthly seminars and the Mining Innovation Symposium, which brings together researchers, students and mining professionals to discuss emerging opportunities and challenges.
“The work that ASU is doing to advance materials science, particularly in minerals processing and recovery, is a game changer,” says Adam Hawkins, director of Global External, a Phoenix consulting firm specializing in stakeholder engagement and public policy for the global mining industry. “Our industry is proud of the work that Khodadadi Tirkolaei and the college are doing to solve complex problems.”
When Arizona Sonoran Copper Company Vice President of Sustainability and External Relations Travis Snider learned about Khodadadi Tirkolaei’s work through a colleague at ADEQ, he arranged a visit to tour the ASU researcher’s lab.
“Once he showed me how they were developing ways to reduce blown dust from tailings and haul roads, I knew that this was the right fit for our industry,” Snider says. “I have always hoped ASU would get more involved in supporting the mining industry we have here in Arizona. I am excited to see where they take this.”
Sophie Dessart, manager of communications and public affairs for Florence Copper LLC, shared her story at one of the initiative’s monthly seminars.
“The students, faculty and industry participants brought thoughtful, forward-looking questions about the future of mining, innovation and sustainability,” she says. “It made for a dynamic discussion and reinforced how important these conversations are at this stage in the industry’s evolution.”
After participating in one of the initiative’s monthly seminars, the company produced its first copper cathode from a new U.S. copper source using the in-situ copper recovery process. This process significantly reduces surface disturbance, water and energy use and greenhouse gas emissions compared to conventional mining methods.
“Innovations like this play a key role in the future of copper production, particularly as demand continues to grow alongside electrification, national defense spending and advanced technologies like AI and data centers,” Dessart says.
Building workforce development together
The ASU Mining Innovation Initiative actively engages with industry professionals and organizations to better understand their workforce needs and build the foundation for a more formal workforce development program.
The team is also connecting “with professionals from mining companies, consulting firms and technology providers who are interested in contributing to training and educational initiatives,” Khodadadi Tirkolaei says.
Faculty members have begun exploring the development of short courses and professional training programs through ASU’s Global Outreach and Extended Education that would align with the evolving needs of the mining and critical minerals sector. The programs would enable industry professionals to access specialized training in areas such as modern mining technologies, sustainability practices and emerging tools that are becoming increasingly important in the industry.
As global demand for critical minerals continues to grow, the mining industry faces a significant gap between industry needs and available talent, and “addressing this gap requires more than technical training,” says Carolina Navia Vasquez, a mine engineer with Freeport McMoRan.
“Workforce development is not only crucial for increasing the number of workers but for enhancing the strength of the industry through innovation, diverse perspectives and resilience. It’s about changing mindsets and empowering people,” Navia Vasquez says.
Growing students’ interest in mining careers
The initiative also focuses on raising awareness among K-12 students about mining careers through outreach activities with industry partners at school and community events.
This year, the ASU Mining Innovation Initiative team and representatives from Ausenco, the American Education Economic Commission and National Exchange for Resource Development — a platform focused on mining and critical minerals education and workforce development — connected K-12 students and their families with mining activities and a virtual reality experience at ASU Homecoming.
During Science Night at Knox Gifted Academy, a K-6 grade school in the Chandler Unified School District, Navia Vasquez joined the team to introduce younger students to the importance of minerals and the role mining plays in everyday life.
“Many students grow up without ever hearing about mining as a career path,” Navia Vasquez says. “Being part of Science Night was an opportunity to change that narrative.”
Early access to information and role models can completely reshape a young person’s sense of what is possible, she says.
ASU’s participation in the Arizona Mining Association’s Mining Day at the Capitol, was a natural extension of these efforts. During the event, ASU faculty members and students answered questions from students, families, teachers and mining professionals about their research.
When high school students asked about her research, civil engineering master’s student Aynur Yildirim explained how her team, led by Ravikumar, is studying ways to recover gallium and indium from discarded LED light bulbs and lamps to help reduce U.S. reliance on imported critical minerals. She shared how the team had already identified three high-use counties that could serve as pilot sites for collection and recycling programs.
The ASU Mining Innovation Initiative plans to continue expanding its outreach efforts, including growing its presence at Mining Day at the Capitol with additional student projects, research demonstrations and interactive exhibits, Khodadadi Tirkolaei says.
Outreach efforts to K-12 is an important part of building interest in the mining industry and critical materials careers, says Whitney Lennon, education program director for the Arizona Mining Association.
Through classroom resources, field trips and hands-on activities, programs such as Mining in the Classroom help students connect mining to the materials used in phones, cars, energy systems and infrastructure while introducing career pathways in engineering, skilled trades, environmental sciences and other fields.
“It’s career-connected learning built around curiosity — helping students see where the materials in their world come from and how they show up in everything from phones and cars to energy and infrastructure,” Lennon says.
As the ASU Mining Innovation Initiative works with industry partners to help develop solutions to issues, build mining workforce development programs and increase interest among Arizonans in mining careers, the team emphasizes that working together is essential.
“Mining is an innovative, sustainable and developing industry that can play a huge role in our future,” Navia Vasquez says. “We are not just creating careers for future generations. Today, we are making decisions for the future of sourcing the raw material necessary to run our planet.”
Why this research matters
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Learn more about ASU discoveries that are contributing to changing the world and making America the world’s leading economic power at researchmatters.asu.edu.
