Buried treasure: The U.S. is throwing away its critical minerals

The United States digs up enough rock each year to cover its need for most critical minerals. Yet elements like cobalt, lithium, gallium, and rare earths still slip through the cracks – ending up in tailings ponds or waste piles instead of being recovered.

The real bottleneck isn’t the supply, but the ability to capture and reuse what’s already mined.

A new study led by the Colorado School of Mines quantifies the opportunity. The team paired mineral production data from federally permitted metal mines with geochemical surveys from national agencies.

Minerals lost in plain sight

The result is a first-of-its-kind estimate of how much critical material already flows through U.S. concentrators and smelters every year, then leaves the process unrecovered.

“The challenge lies in recovery,” said lead author Elizabeth Holley, an associate professor of mining engineering. “It’s like getting salt out of bread dough – we need to do a lot more research, development, and policy to make the recovery of these critical minerals economically feasible.”

The database spans 70 elements used in everything from phones and medical devices to satellites, wind turbines, and fighter jets.

It shows that, for all but two – platinum and palladium – unrecovered byproducts from ongoing U.S. mining could meet domestic demand if even small fractions were captured.

The minerals mines leave behind

America’s mines for gold, copper, zinc, nickel, and molybdenum handle enormous volumes of rock, with trace elements tagging along in the ore.

Because U.S. plants are optimized for the primary metals, the trace values typically leave in tailings. The new analysis estimates that capturing slivers – often less than one percent – could transform supply.

“This is a brand-new view of ‘low-hanging fruit’ – we show where each critical mineral exists and the sites at which even one percent recovery of a particular critical mineral could make a huge difference, in many cases dramatically reducing or even eliminating the need to import that mineral,” Holley said.

Consider cobalt. It hitchhikes through nickel and copper circuits. Recovering under 10 percent of the cobalt currently mined and processed but not saved would cover the entire U.S. battery market.

Germanium – vital for infrared optics and defense sensors – occurs in some zinc and molybdenum deposits. Recapturing under one percent of the germanium now lost from those mines could erase the nation’s import dependence.

Tracking minerals in mine waste

The researchers assembled annual output from U.S. metal mines and matched it to ore chemistry using a statistical resampling method. They drew on recent geochemical compilations from the U.S. Geological Survey, Geoscience Australia, and the Geological Survey of Canada.

By fusing production volumes with typical concentrations for co-occurring elements, they approximated the quantities of critical minerals already entering U.S. processing streams at mines- and then heading to waste.

Those tailings are not benign. They must be stored, monitored, and sometimes remediated to prevent contamination of air and water.

Recovering value from them, or better yet before they reach the waste pile, would shrink the waste footprint and lower long-term environmental liabilities.

Why recovery is hard – and worth it

Existing mills are designed to extract one or two main metals efficiently. Capturing gram-to-kilogram-per-ton traces requires new flowsheets, reagents, and hardware. It can also mean slowing a plant or adding stages that raise costs. That’s why economics, not geology, is the constraint.

“Now that we know which sites are low-hanging fruit, we need to conduct detailed analyses of the minerals in which these chemical elements reside and then test the technologies suitable for recovery of those elements from those specific minerals,” Holley said.

Technology is only half the equation. Without the right incentives, mine operators have little reason to retool for tiny revenue streams that can be volatile.

“We also need policies that incentivize mine operators to incorporate additional processing infrastructure,” noted Holley.

“Although these elements are needed, their market value may not be sufficient to motivate operators to invest in new equipment and processes without the right policies in place.”

Benefits beyond the mine

Recovering critical minerals onshore strengthens supply security for energy, defense, and technology. It reduces exposure to geopolitical chokepoints and volatile import markets.

Mineral recovery also creates new revenue lines from rock already mined, delinked from permitting new pits.

The environmental dividend is real. Every extra ton recovered from existing ore reduces the need to dig and crush new rock somewhere else. It also cuts the mass and toxicity of tailings piles by removing elements that can complicate long-term storage.

In some cases, recovered byproducts can feed low-carbon technologies – neodymium for high-strength magnets, lithium for batteries – creating a virtuous loop.

From trash to treasure

The study reframes U.S. critical mineral strategy. Instead of treating supply as a greenfield problem, it points to hundreds of “brownfield” opportunities hidden in plain sight.

Holley’s conclusion is straightforward: the United States already extracts the very atoms it classifies as critical. The problem is that they exit the process through the wrong stream.

With focused science and well-designed incentives, that stream can be redirected – transforming “waste” into the strategic materials needed for an electrified, digitized economy.

The study is published in the journal Science.

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