Environment

Hidden Treasure: US Discovers $8.4 billion Worth of Rare Earth Metals in Coal Ash Landfills

A study estimates that U.S. coal ash holds 11 million tons of rare earth elements

By: Brian Argueta, Journalist

March 18, 2025

A large quarry dump used in mining operations.

For decades, the United States has relied on foreign rare earth elements, the essential materials that are used in everything from cell phones to clean energy technologies.

But in a shocking revelation, scientists at The University of Texas at Austin discovered a vast domestic source that has been hiding in plain sight all along.

Hidden away in the nation’s coal ash piles is an astonishing $8.4 billion worth of these vital materials—a finding that can significantly reduce imports and transform the U.S. approach to securing critical minerals.

From Waste to Wealth

Coal ash, the dusty remains after coal is burned to produce electricity, has been an industrial waste for decades. However, researchers have now identified coal ash as a readily accessible and valuable source of rare earth elements. These are crucial in producing batteries, solar panels, and high-performance magnets.

This is the ‘trash to treasure’ concept,” said Bridget Scanlon, co-lead author of the study and a research professor with UT Austin’s Bureau of Economic Geology. “We are attempting to close the loop by recycling resources from waste and simultaneously reducing environmental impacts.”

Striking Gold with Global Implications

U.S. coal ash contains an estimated 11 million tons of rare earth elements—almost eight times the country’s known domestic reserves, according to the study.

This is the country’s initial overall assessment of coal ash as a resource, a novel means of augmenting America’s essential mineral supply.

There is a benefit to producing minerals from coal ash over traditional mining. The minerals are already partially refined out of their parent material by burning, eliminating high-energy refinement processes that are a routine part of mining.

“Throughout the country, there’s just huge amounts of this stuff available,” states University of Wyoming research scientist Davin Bagdonas. “And the initial process of extracting it from the earth has already been done for us.”

Regional Variations

As per the research, coal ash varies regionally in rare earth element composition, and this regulates the ease by which the elements are extractable.

The Appalachian Basin coal ash has the highest density with an average of 431 milligrams per kilogram. However, only 30% of these constituents can easily recover. As an alternative, Powder River Basin coal has a lower density (264 mg/kg) but with a 70% extraction rate and thus is a more suitable one for bulk recovery.

“These are significant differences because they tell us about the most economically valuable deposits to mine,” Scanlon said. “It is a general analysis that has never been done before and is a good foundation for further study.”

Turning Potential into Reality

Although the discovery is promising, there are still obstacles to getting over in turning it into a viable possibility.

Companies like Element USA are working on the technology and staff to extract rare earth elements from tailings and coal ash.

“Extracting rare earth elements from tailings is common sense,” said Element USA chief strategy officer Chris Young. “The challenge is making that reasonable idea economically viable.”.

With more investment being focused on domestic rare earth recovery, America has a deep choice to make. In becoming more dependent on this unrecovered reserve, America would reduce the country’s reliance on foreign sources and transform overabundance into a strategic material.