Could Coal Waste Be Used to Make Sustainable Batteries?

Acid mine drainage has long been a scourge in Appalachia. Recent research suggests that we may be able to simultaneously clean up the pollution and extract the minerals and elements needed to power green technologies.


By August 26, 2022


Illustration by Leif Gann-Matzen

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On a recent afternoon, near the headwaters of Deckers Creek, in West Virginia, Paul Ziemkiewicz, the biological scientist who directs the Water Research Institute at West Virginia University, squatted by a blood-red trickle seeping from a hillside. The color, he pointed out, was the telltale sign of water contaminated by a form of coal waste called acid mine drainage, which poisons aquatic life. For decades, this contaminated water has devastated Appalachia, killing many of the creeks and rivers that lie between Kentucky and southwestern Pennsylvania. “I’ve spent thirty-two years making this waste go away,” Ziemkiewicz told me. He had come to meet Brian Hurley, the executive director of Friends of Deckers Creek, a local watershed group that had been working to clean up the waste. Hurley had shaggy hair, and wore rubber boots and sunglasses propped on the brim of his baseball cap. In another era, he might’ve found work in a local coal mine, or a steel mill, but those industries were mostly gone. There are, however, increasing opportunities in cleaning up the mess left behind. Part of Hurley’s job is to monitor the water-treatment systems for the creek, some of which Ziemkiewicz had helped to design. “You can make a living now fixing things and making them better,” Hurley said.

Ziemkiewicz, who is lean and studious-looking, explained that acid mine drainage forms when air and water come into contact with the exposed and pyrite-rich rock on the surfaces of mines, starting a chemical reaction that releases sulfuric acid, which then flows into creeks. Ziemkiewicz directed Hurley to open the metal door of the treatment system, which looked like a miniature grain silo built over the seep. Inside, a waterwheel dropped chalky white lime dust into the vermillion stream below. “It’s a glorified eggbeater,” Hurley said. The lime, a base, neutralizes the acid in the contaminated water. The water then flows from the silo into a large holding pond, where heavier metals and other elements drop out, forming a rainbow sludge. The puddles of sludge take on vivid hues: glacial blue indicates the presence of aluminum; terra-cotta red means iron. The treated water then flows from the pond, down the bank, into the creek.

West Virginia is the second-largest coal producer in the United States, and coal-patch communities have often been left paying the bill for cleaning up the contamination that companies leave behind. But recent research has indicated that coal waste also contains critical minerals and materials, including cobalt, manganese, and lithium, and rare-earth elements, such as neodymium. These are essential to a wide range of high-tech products, including the magnets used in wind turbines and the ultra-lightweight batteries used in computers, smartphones, and a variety of modern weaponry. Ziemkiewicz said, “These alloys make things lighter, faster, and allow for increased temperature.” Decarbonizing the economy, to mitigate the ravages of climate change, will also require producing many more highly efficient batteries, and this process will require supplying these materials in larger quantities.

Right now, many such materials are mined in places like Congo, where labor practices involve large-scale abuses, including, reportedly, forced child labor in cobalt mines, sometimes involving children who have been drugged. Others are produced in China, which maintains tight strictures on manufacturing and export. This model is bad for the American economy, and it creates challenges for supply chains, as well as for national security, since it requires the U.S. to outsource the development and manufacturing of certain sensitive technologies to Chinese factories. “The Chinese can assure a local factory access to a rare-mineral supply, but the U.S. can’t,” Ziemkiewicz told me. “We have exactly one mine in this country producing rare earths at all, and they’re taking their concentrates and sending them to China.”

In the past several years, however, American scientists have succeeded in extracting critical minerals and materials from coal waste. If this effort proves efficient and effective, we may be able to simultaneously clean up polluted places and secure access to rare resources. These resources could then be used to bring sensitive manufacturing back to the U.S., provide supplies used for military technologies, and help create more sustainable energy sources. “Fossil communities are solving something Silicon Valley can’t,” Jennifer Wilcox, the principal deputy assistant secretary of the Office of Fossil Energy and Carbon Management at the Department of Energy, told me. “This does more than restore the environment. It also restores these communities that have paid so much for America’s energy.”

Ziemkiewicz is leading the effort to harvest critical minerals and rare-earth elements from Appalachia’s acid mine drainage. “It has every metal that I’ve ever looked for,” he said. In 2019, he was awarded five million dollars by the Department of Energy, to work in conjunction with the West Virginia Department of Environmental Protection to build the first pilot-scale facility in the country to process waste and extract critical materials from acid mine drainage. The facility, which began initial operations this summer, will produce between one and a half and three tons of critical minerals and rare-earth elements annually.

Rumors of the potential uses for coal waste have spurred a wave of interest. At the creek, Ziemkiewicz plucked a square stalk with blue flowers growing among the flat blades of grass, and spun it in between his thumb and forefinger. “See how it’s cruciform?” he asked, offhandedly. “This is borage.” Hurley asked him, “Are you getting calls from landowners and mine operators?” Ziemkiewicz replied, “About two a week. I also got one from an electric-car manufacturer, but I’d better not say who.”

Ziemkiewicz is enjoying an unusual reversal: the waste that coal companies have long disowned is suddenly of interest.The shift intrigues him. The grandson of a coal miner, Ziemkiewicz was born and raised in southwestern Pennsylvania, along the Allegheny River. He grew up a few miles from Springdale, the home town of Rachel Carson, author of the environmental classic “Silent Spring.” His high-school science teacher, who was apparently a friend of Carson’s, hired Ziemkiewicz for his first job, teaching local kids about the outdoors. Ziemkiewicz spent his summers fishing with his uncles, who were steel workers. Most of the time, they caught nothing, since acid mine drainage, and other industrial pollutants, had killed almost everything in the river.

Early on, he decided that his life’s work would be reclaiming the landscapes and ecosystems that have been ruined by mining. He moved to British Columbia for his studies, where he worked as a botanist, replanting barren mine lands with grasses and legumes that were hearty enough to survive, such as alfalfa and clover. By the nineties, he was working on acid mine drainage. Thanks in part to the Surface Mining Control and Reclamation Act, the government was providing grants to clean up the damage left behind by abandoned mines. Ziemkiewicz has spent decades driving through the hollows of West Virginia, helping to found watershed groups, citizen-led organizations that aim to restore the health of local water systems. These groups weren’t made entirely of ardent environmentalists: they were broad coalitions that included professors and teachers who were passionate about cleaning up local waters, along with former coal miners who valued hunting and favored using natural resources prudently. Ziemkiewicz brokered unusual alliances between coal companies, environmental groups, and state and federal governments, which worked together to clean up the sites of abandoned mines. One morning, he took me on a sixteen-mile trail ride along a thriving stretch of the Monongahela River that had been reclaimed as a result of his work. A nearby trail bustled with outdoor enthusiasts wearing spandex.

 “This stretch of river was dead when I arrived,” he said.

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For scientists who study coal waste, it was not a surprise that the waste contained critical minerals. “I know what’s in there,” Ziemkiewicz said. The eureka moment occurred at a laboratory at West Virginia University, where a team of scientists led by Ziemkiewicz proved that these minerals and materials could be recovered from acid mine drainage. In 2019, President Donald Trump’s Department of Energy began expanding a program that was investigating the extraction of rare-earth elements from coal waste. The Trump Administration likely reasoned that, if the coal waste was seen as valuable rather than hazardous, its production would be less of a downside to future mining. The Administration was also keen to bring industrial production from China to the U.S.

When Joe Biden became President, the Administration reset its goals: a roughly fifty-per-cent reduction in emissions by 2030, a completely clean electrical grid by 2035, and net-zero greenhouse-gas emissions by 2050. Wilcox and her colleagues reviewed existing programs, including the coal-waste program. “We wanted to make sure that they didn’t simply enable industry,” she told me. They decided that they should keep the program going, not to boost coal mining but to clean up affected communities and increase the supply of critical materials, which would help produce sustainable energy. “We have so much stockpiled waste from fossil power and industrial sectors that, using this legacy waste, we have significant production potential for rare-earth elements and critical minerals,” Wilcox told me. “Our back of the envelope says we can meet the U.S. needs of our clean-energy goals from this waste,” she added. “We’ll no longer need to rely on places like Congo for cobalt mining. At the same time, we can create jobs in transition communities and clean up these areas ravaged by mining.”

Ziemkiewicz’s project is now one of four small-scale pilot programs supported by the Department of Energy. “All have demonstrated that we can take coal, coal refuse, coal ash, and acid mine drainage and produce high-purity rare-earth elements,” Grant Bromhal, the acting director of the Minerals Sustainability Division at the Department of Energy, said. He noted that there are twelve critical materials required for clean energy, sometimes called the “dynamic dozen,” and that the list is growing: cobalt, dysprosium, gallium, germanium, graphite, iridium, lithium, manganese, neodymium, nickel, platinum, and praseodymium. The potential domestic supply of these materials is abundant. “We are the Saudi Arabia of coal waste,” he told me. Coal ash, for instance, sits in massive ponds that can occupy hundreds of acres; mine tailings can form mountains of rubble and hard rock. In Lowell, Vermont, for instance, stands a pile of tailings hundreds of feet tall, from what was once the United States’ largest chrysotile asbestos mine.

After our trail ride, Ziemkiewicz and I returned to his Chevy Blazer, and he pulled on work pants and drove us two hours southeast of Morgantown, a small city near the Pennsylvania border. We crossed barren straits that ran above underground mines. Then the Blazer climbed Backbone Mountain and crossed the eastern Continental Divide. We pulled onto an unmarked gravel road and jounced on toward the construction site where Ziemkiewicz’s team—along with the West Virginia Department of Environmental Protection and the U.S. Department of Energy—was building the facility to recover critical materials and rare-earth elements from acid mine drainage.

Ziemkiewicz has a picture in his office of himself and Senator Joe Manchin, who has expressed support of his program. “Recycling provides a tremendous opportunity to avoid outsourcing the raw supply of critical minerals we need while creating new economic opportunities right here at home,” Manchin said, at a congressional hearing in the spring. Ziemkiewicz keeps his politics to himself. In the past, he has called himself “a Trotskyite,” but he believes that the success of his past three decades of work, reclaiming thousands of miles of rivers and streams in Appalachia, is based on sharing knowledge across a wide array of communities. Although he has spent most of his life building tools to help clean up after coal companies and has testified against their dangerous practices in court, he resists speaking ill of the industry. He told me stories of what he had seen—once, he said, he watched miners discover what appeared to be fossilized dinosaur footprints, but no one dared mention it, since acknowledging them could halt mining—but he told them in an agnostic manner, without judgment.

By the time that we arrived at the site of the future facility, it had started to rain, and Ziemkiewicz popped his trunk to offer me a raincoat. There, in the back, sat his old white hard hat, covered with stickers from mining concerns. When I began to criticize them, he blinked at me, hard. We were in coal country, and his most talented engineers on this project came from the industry; to wag fingers at coal here would alienate potential allies. Technocrats in Washington, D.C., can afford political polarization, he said, but many people living in Appalachian communities are accustomed to working across divides to solve common problems. Beyond the contributions of the engineers, coal companies and mining operators were an integral part of this program as well: they owned vast tracts of land and were sometimes willing to partner with the state to clean up discharged acid mine drainage.

We stood in a large unfinished shed on the construction site, listening to raindrops hit the corrugated roof. Ziemkiewicz noted that the facility would take in about five thousand gallons of acid mine drainage each year from a massive defunct coal mine at the top of the ridge, and would run the contaminated water through a series of holding tanks and ponds to dry it out into bales, which could then be transported to his lab by truck and be separated into valuable elements. “When you start with rock, you have to grind it up, and use very strong and extreme processes to get the rare earth,” he told me. But, when extracting the materials from coal waste, “the acid in the waste already puts minerals into solution, so nature has done most of the heavy lifting for us.”

Sustainability researchers from the Rochester Institute of Technology point out that there is significant variation in the types and amounts of critical materials present in different reservoirs of coal waste. This means that not all waste will be profitable to purify. As the researchers have written, “The value of rare earths in a single ton of coal ash can vary from US$99 at a coal plant in Ohio to $534 at a West Virginia plant. With extraction costs expected to range between $380 and $1,200 per ton, not every coal plant’s ash will be a profitable place to find rare earths.” There are also concerns that the chemicals used to harvest critical minerals could be damaging. “Generally, these processes are energy intensive, using solvent extraction technologies that are not environmentally friendly,” Maria Holuszko, a coal and mineral processing engineer and associate professor at the University of British Columbia, said in an interview. (Ziemkiewicz noted that these chemicals are used in much smaller quantities when dealing with acid mine drainage.) And some critics worry that harvesting materials from coal waste will only give mining companies an excuse to continue mining. Ziemkiewicz was careful to note that cleaning up acid mine drainage was only a small part of the much larger program necessary to clean up America’s energy infrastructure.

If the effort to harvest these materials from coal waste proves profitable, it remains uncertain who will reap the benefits. Coal companies have long disavowed responsibility for the waste they produce, abandoning mine land and washing their hands of the duty to clean up. A new market for coal waste might allow mining companies to benefit from these pollutants. Ziemkiewicz has spearheaded a legal effort to make sure that the profits—“the goodies,” as he put it—from the critical minerals go to the groups cleaning up the waste, such as Friends of Deckers Creek. To that end, he recently helped to get House Bill 4003 in West Virginia off the ground. An early version of the bill reads: “Previously considered a liability, ownership of acid mine drainage treatment byproducts is poorly defined. This legislation seeks to clarify ownership of these byproducts in order to incentivize acid mine drainage treatment while recovering rare earth elements and critical materials.” The bill went into effect earlier this summer, and serves as a model to keep the economic benefits of coal waste within the region. Those benefits could be substantial: as estimated by the Department of Energy, the concentration of critical materials in coal waste is vast, enough to potentially produce enough graphite to power every cell-phone battery in America. Ziemkiewicz, for his part, will be happy if some streams in the region get cleaned up along the way. “As far as I’m concerned, it’s about incentivizing cleaning up acid mine drainage,” he said. “That’s enough.” ♦



Eliza Griswold, a contributing writer at The New Yorker, won the 2019 Pulitzer Prize for general nonfiction for “Amity and Prosperity.” Her latest book is “If Men, Then: Poems.”