Critical minerals are hiding in plain sight in U.S. Mines

Critical mineral byproducts are elements that occur naturally alongside metals like copper, gold, zinc, or nickel. These secondary minerals are not the main target of mining operations, so they are often separated out and discarded during processing. According to the researchers, recovering even small amounts of these overlooked materials could have a major impact on U.S. supply chains.

The researchers found that if 90 percent of these byproducts were recovered, they "could meet nearly all U.S. critical mineral needs; one percent recovery would substantially reduce import reliance for most elements evaluated." This means that even modest improvements in recovery technology could significantly reduce dependence on overseas sources.

What Are Critical Minerals and Why They Matter

Critical minerals are materials that are essential to the economy and national security but face supply risks due to limited domestic production or geopolitical instability. In the United States, this category includes minerals such as cobalt, nickel, manganese, lithium, tellurium, germanium, and many others.

These elements play key roles in modern technology. They are used in rechargeable batteries for electric vehicles, magnets for wind turbines, semiconductors for electronics, and solar panels for renewable energy. Some are also vital for defense systems, medical devices, and communications equipment.

Demand for these materials is growing rapidly as clean energy technologies expand. At the same time, many critical minerals are currently imported from regions affected by political tension or trade uncertainty. Developing entirely new mines can take decades, making alternative domestic sources especially attractive.

How Researchers Measured Untapped Mineral Potential

To estimate how much of these minerals could be recovered inside the United States, Holley and her colleagues combined two large datasets. One database tracked the main commodities produced at federally permitted U.S. metal mines. The other included detailed geochemical measurements showing the concentrations of 70 critical minerals found in ore samples across the country.

By pairing production data with mineral chemistry data, the team was able to estimate how much of each critical mineral is already being mined and processed, but not recovered. Instead, these materials end up in mine waste, also known as tailings, which must be stored and monitored to prevent environmental harm.

In many cases, the study found that recovering less than 10 percent of these byproducts would generate a higher total dollar value than the primary metals currently being sold by U.S. mines. This suggests that what is treated as waste today could become a major economic resource.

Economic, Strategic, and Environmental Benefits

The potential benefits of recovering critical mineral byproducts extend beyond economics. Reducing import dependence would strengthen supply security for industries tied to energy, technology, and defense. It could also help protect the U.S. from supply disruptions caused by international conflicts or trade restrictions.

There are environmental advantages as well. Recovering valuable minerals instead of discarding them would reduce the volume and long term impact of mine waste. It could also create new opportunities to reuse processed materials in construction and other applications.

Despite the promise, challenges remain. Recovering small amounts of minerals from complex ore mixtures requires advanced technology, additional processing steps, and supportive policies. As Holley has explained, the difficulty lies in making recovery practical and cost effective at scale.

Still, the findings point to a largely untapped opportunity. Active U.S. mines are already handling the materials needed for batteries, clean energy systems, and high tech manufacturing. With targeted investment, research, and policy incentives, these hidden byproducts could become a powerful domestic resource rather than a discarded one.