How the U.S. Can Mine Its Own Critical Minerals − without Digging New Holes
The other location is in Mountain Pass, California, where hard rock mining extracts a rare earth carbonate mineral called bastnaesite. Yet again, much of the material is sent abroad for refining. As a result, the entire supply chain − from mining to final use in products − stretches across continents.
Meeting the U.S. demand for rare earth elements and other critical minerals from operations within the United States will require more than just opening new mines. It will require developing and scaling up new technologies, as well as building processing operations.
Historically, processing has largely taken place overseas because of the environmental impacts, energy demand and regulatory constraints.
The Potential, but Long Road, to New Mines
Investment in exploration activity for critical minerals is rapidly increasing across the U.S.
In 2017 the U.S. Geological Survey launched the Earth Mapping Resources Initiative − known as Earth MRI − to identify potential sources of critical minerals within the country.
Some areas that appear promising for rare earth elements have lots of chemical weathering, in which rocks containing rare earth elements are broken down by reacting with water and air. Exploration is underway at several of these sites, including in locations in Wyoming and Montana.
Identifying a resource, however, is not the same as producing it.
Traditional mining can take a decade or two from exploration to production and up to 29 years in the U.S., the second-longest timeline in the world. Although this timeline could be changing under the current administration, companies might still face major uncertainties related to permitting, infrastructure development and, in some places, community opposition. Managing environmental impacts, such as air and water pollution and high water consumption and energy use, can further increase cost and extend project timelines.
Given that the exploration projects mentioned above are still in early stage, the U.S. needs additional, parallel efforts that can bring resources to the market at an accelerated pace.
Mining the Materials We Have Already Mined
One of the fastest ways to increase U.S. rare earth production may not require digging new holes in the ground − but rather returning to old ones.
The Atlantic coast region stands out on the Earth MRI map as a particularly promising area. What’s even better is that this region has already established extensive mining activities and mature infrastructure, which allows for much faster speed to market.
Georgia has mineral sand deposits that are rich in titanium, zirconium, and rare earth elements. Titanium and zirconium − both used in aerospace, energy and medical applications − are already mined in Florida and Georgia. In southeast Georgia, rare earth elements found with these heavy mineral sands are already being recovered as rare earth concentrates.
Kaolin, a white clay used in paper, paint and porcelain, has been mined in Georgia for over a century, and it can also contain rare earth elements. Georgia generates more than 8 million tons of kaolin annually, making it the leading U.S. producer and a large exporter. This also comes with millions of tons of mining and processing residues, or what’s known as tailings.
Recent research studies suggest that there is significant potential for extracting rare earth elements in the tailings.
The tailings are already mined and sitting on the surface. There is no need to drill or blast. That means existing infrastructure, faster timelines and lower costs and than new mining operations.
Technological innovations, such as bioleaching, ligand-based extraction and separation and electrochemical separation, are now making mining these legacy wastes possible. New processing facilities could be built near existing kaolin or heavy mineral sand operations or former mine sites, bringing materials to market in a few years rather than decades.
The Future of Waste Mining
This approach is part of a broader strategy known as “waste mining,” “urban mining” or “mining the anthropogenic cycle.”
It involves the recovery of critical minerals from existing waste streams such as mine tailings, coal ash and industrial byproducts. It is also part of building a circular economy, where materials are reused and recycled rather than discarded.
The U.S. has the potential to catalyze new domestic supply chains for materials essential to national security and technology. Waste mining and recycling are critical pieces to ensure the long-term sustainability of these supply chains.
Yuanzhi Tang Professor of Biogeochemistry, Georgia Institute of Technology. Scott McWhorter is Distinguished Fellow in the Strategic Energy Institute, Georgia Institute of Technology. This article is published courtesy of The Conversation.
