A mining technology pioneered by researchers at the Bureau of Economic Geology at The University of Texas at Austin could reduce the amount of energy needed to access critical minerals vital for modern energy technologies and capture greenhouse gases along the way.
Transitioning the world’s energy to technologies and sources with low-carbon emissions will take, in part, tremendous amounts of lithium, nickel, cobalt and other critical minerals that exist in low concentrations in the Earth’s crust. Mining those elements takes much energy and produces waste, which can negatively affect the environment and create significant amounts of greenhouse gas emissions such as carbon dioxide (CO2).
This research could turn these emissions into a tool by using CO2 to weaken the rock containing critical minerals, reducing the amount of energy needed for mining. The ultimate goal is to significantly reduce the emissions produced during mining by storing them safely in the rocks, and potentially even make mining carbon negative – storing more carbon than is produced – by piping in and storing CO2 emissions from other industrial operations.
This CO2 storage is possible because of the way ultramafic rocks, which typically contain critical minerals, react with carbon. The CO2 chemically reacts with the rock to mechanically break its structure, making the minerals easier and less energy intensive to mine. This reaction also partially turns the rock into a limestone, incorporating the carbon dioxide into the mineral structure and storing it permanently.
“Mining processes create a lot of CO2 as a byproduct,” said Estibalitz Ukar, a research scientist at the Bureau of Economic Geology at the UT Jackson School of Geosciences. “If you can capture what is produced at the mine, then you can come up with a low-emission operation, which is good, but we want to use the CO2-reducing properties of ultramafic rocks to help eliminate even more CO2.”
Ukar is leading a team of scientists that is working to perfect the mining technology, which is supported by a $5 million grant from the U.S. Department of Energy Advanced Research Projects Agency-Energy. The three-year project will work to refine the mining method in the lab for two years before trying a full-scale field test in partnership with Canada Nickel Company. The field test is planned to take place in one of 20 newly discovered ore bodies near the U.S.-Canada border that are forecast to be an important new source of critical minerals in North America.
The project would also make low-grade deposits more economically viable, an important step in increasing the available supply of domestically produced critical minerals.
“The demand is high now, but we will see a huge increase in the next three to five years as we transition into lower-emission technologies, such as electric vehicles,” Ukar said. “We need to meet the demand by finding creative ways to reduce costs and emissions, find new sources of metals, and make the mines of the future more sustainable. And we need to do it fast.”
The project is part of the Mining Innovations for Negative Emissions Resource Recovery program, a new initiative that aims to develop market-ready technologies that will increase domestic supplies of critical elements required for the transition to low-carbon or carbon-free energy.
The research brings together the expertise of scientists from the Bureau of Economic Geology and Department of Geological Sciences in the UT Jackson School, as well as researchers from the UT departments of Petroleum & Geosystems Engineering and Aerospace Engineering & Engineering Mechanics; Columbia University; the University of Bern; and Carbfix, an Iceland-based project using a similar method to store CO2 in basalt.
Several groups from the Bureau of Economic Geology are a part of the project. These include the Gulf Coast Carbon Center, a world leader in monitoring carbon to make sure it is safely stored. Experts from the bureau’s TexNet seismic monitoring system are also part of the team, and will help determine if the new mining method causes any seismic activity.
“Lowering the emissions from energy, in an affordable and reliable way so that the global population can afford it, is the great challenge,” said Bureau of Economic Geology Director Scott Tinker. “This research program, if successful, could be one of several approaches to help advance that effort. The integrated team is critical to success.”