In coal country, a new chance to clean up a toxic legacy

Waste from abandoned and bankrupt mines has contaminated more than 12,000 miles of waterways. Now states are looking at how to extract critical elements from those waters to try to offset the high cost of cleanup.

University students sift iron oxide-filled mud from acid mine drainage collected from a discharge site next to Sunday Creek in Millfield, Ohio, in October.
University students sift iron oxide-filled mud from acid mine drainage collected from a discharge site next to Sunday Creek in Millfield, Ohio, in October. (Dane Rhys)
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On the site of a shuttered and bankrupt coal mine near the headwaters of the Potomac River, the state of West Virginia is building a demonstration plant that researchers say could help spur efforts to clean up thousands of miles of waterways contaminated by coal-mining waste.

After decades when coal states struggled to pay for the costs of cleaning up contaminated rivers and lakes, recent scientific advances and new technology make it far more feasible to recycle the highly acidic and mineral-rich liquid coal waste known as acid mine drainage (AMD), these researchers say.

And on the site of what was once the Buffalo Coal Company’s A34 surface mine, there is an additional financial and strategic incentive. When it’s fully operational — in late summer or early fall, according to the West Virginia Department of Environmental Protection — the Buffalo Coal A34 plant will recover critical metals including cobalt and nickel and the rare earth elements used in cellphones, electric cars and other technology from those toxic waters.

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The recovery of those elements could help reduce the ongoing cost of mine cleanup and lessen America’s reliance on China for materials critical to the shift to a clean energy economy. While these initiatives don’t currently pay for themselves, they are gaining traction for their role in tackling the legacy of dirty energy while trying to minimize the environmental impact of the new energy that’s replacing it. “If your sludge has value, why throw it in the garbage can?” said Paul Ziemkiewicz, director of West Virginia University’s Water Research Institute, which has pioneered research into recycling acid mine drainage.

Across the country, waste from abandoned and bankrupt coal and metal mines has contaminated more than 12,000 miles of waterways. This legacy pollution — the toxic byproduct from over half a century of mining — threatens drinking water, corrodes infrastructure and devastates aquatic life.

However, cleanup costs for acid mine drainage remain prohibitive — requiring the construction of water treatment plants and operating them over years and decades. West Virginia alone has 184 treatment sites for AMD, with operating costs of about $4 million a year, according to the state’s Office of Surface Mining.

The emergence of new technologies and the push provided by the Biden administration’s climate goals, which include carbon-free electricity by 2035, are shifting the calculus for cleanup. “The potential to recover rare earths from acid mine drainage and other streams in the coal production and combustion process represent an example of a broader set of potentially unconventional but transformative sources for securing access to rare earth elements,” said Rod Eggert, deputy director of the Critical Materials Institute and professor of mineral economics at the Colorado School of Mines.

Although recycling rare earths from mine waste currently is not commercially viable, Eggert said there was still an argument to be made for pursuing those projects. “It could be worthwhile from a public policy perspective to support communities and regions that traditionally produced coal, and that would be worthwhile or appropriate for public policy if along with producing rare earths as a salable project, we could also clean up waste from the past,” he said.

The infrastructure plan President Biden signed into law last year includes over $11 billion in funding to clean up abandoned mines and affected waterways. A report last year from the Ohio River Valley Institute estimated that only about a quarter of coal mines abandoned before federal regulations took effect in 1977 had been reclaimed, and that it would cost more than $20 billion to clean up the remaining sites.

In February, the U.S. Energy Department launched a $140 million program to build a commercial-scale plant to extract rare earths and other critical minerals from coal waste.

Rare earths are essential to power clean energy products such as wind turbines and electric vehicles. Demand for these critical minerals reached an all-time high last year, with the International Energy Agency predicting it will increase three to seven times by 2040.

The Buffalo Coal A34 site will cost the state $8.7 million, according to the West Virginia DEP. It will siphon off and process 1.4 million gallons of polluted water each day — recovering up to 400 tons a year of rare earths plus cobalt and nickel, Ziemkiewicz said.

He acknowledges that recycling those elements won’t generate enough income to cover the costs of cleanup.

“It wouldn’t be a king’s ransom,” Ziemkiewicz said. “I don’t want to give people the impression that they want to start acquiring liabilities for old AMD sites to acquire rare earths, because you’d lose money on that proposition. But if there’s a broader reason like cleaning up a watershed, you could configure it to recover rare earths.”

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The plant works by pumping contaminated water into giant, circular tanks and incorporating lime, which raises the pH. The coal waste materials — including heavy metals like nickel and cobalt — drop to the bottom of the tank and then are pushed to the center hub, where they collect as brown sludge. To extract rare earths from these tanks, researchers then adjust the pH level to target rare earths instead of the general soup of heavy metals.

Over half the global supply of rare earths — and 78 percent of U.S. supplies — currently comes from China. After weaving in and out of bankruptcies, California’s Mountain Pass, the United States’ only rare earths mine, in 2021 produced 15 percent of global supply.

Other researchers are trying to develop technology to mine solid coal waste for rare earths. Outside the former coal town of Providence, Ky., researchers from the University of Kentucky are working on a pilot project with $11 million in Energy Department funding to extract rare earths by dripping acid over a 2,000-ton pile of coal waste.

An early study projected the plant could process almost 3,000 gallons of artificial AMD each day. Researchers are hoping to gain the funding for a scaled-up commercial version of the plant, which they estimate could produce 300 to 400 tons of rare earths each year — although they acknowledge that even that won’t make much of a dent in America’s dependence on China.

“It’s a secondary source of rare earths; it’s not going to be a primary source,” said University of Kentucky mining professor Rick Honaker, who is heading the research.

But moving from cost savings to profitability from coal waste is still a big leap.

Marty Weems, North American president of American Rare Earths Ltd., an exploration company focused on the development of rare earth deposits, said it’s unlikely that extracting rare earths from coal refuse is economically viable in today’s markets without government subsidies.

And while the plants can salvage rare earths from coal waste pilot projects, there are no industrial-scale separation and purification processing facilities outside of mainland China.

Still, efforts to make coal waste cleanup more affordable continue.

On Sunday Creek, a seven-mile stretch through the southeastern corner of Ohio that counts as one of the state’s most polluted rivers, another novel plant aimed at cleaning up coal waste is scheduled to break ground this summer and start operations in 2024.

The state has struggled to pay for the reclamation of thousands of AMD sites.

The True Pigments pilot plant, a collaboration among Ohio University, environmental advocacy group Rural Action and Ohio’s Department of Natural Resources, aims to harvest the iron oxide that turns the water a bright orange and turn it into pigment for bricks and tiles as well as artist-grade paints.

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“The goal of the project is that the anticipated revenue from pigment sales would be used to offset plant operation and maintenance costs,” said Sarah Wickham, communications officer for Ohio’s Department of Natural Resources.

Recovery will take time, and the stream will never be restored to its pristine state.

“The discharge from the mine will never go away,” she said. “Water quality could improve over decades but will always continue to flow and produce acid mine drainage.”

Guy Riefler, professor of civil engineering and the primary researcher for True Pigments, said a facility like True Pigments is “absolutely replicable” across polluted sites in Appalachia.

“I think it has real potential to help a lot of communities,” said Riefler. “Because in addition to cleaning up the stream it’s a potential revenue source.”

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