On the other side of Appalachia, rust-colored water seeps out abandoned coal minesturning rocks orange and covering streambeds with metals. These acid discharges, known as acid mine drainageare among the most persistent environmental problems in the region. They disrupt aquatic life, corrode pipes and can contaminate drinking water for decades.
However, hidden within that orange drainage are valuable metals known as rare earth elements essential for many technologies that the US relies on, including smartphones, wind turbines and military aircraft. Studies have even shown that concentrations of rare earth metals in acid mine waste may be comparable to the amount of ores mined to extract rare earth metals.
That’s what scientists estimate over 13,700 miles of U.S. streams, primarily in Pennsylvania and West Virginia, are polluted by acid mine discharges.
A closer look at acid mine drainage from abandoned mines in Pennsylvania by the Pennsylvania Fish and Boat Commission
We and our colleagues at West Virginia University have been working on ways to turn the acidic waste in those bright orange creeks into a reliable domestic source for rare earths and clean the water at the same time.
Experiments show that extraction can work. If states can also find out who owns that mining waste, the environmental costs of mining can contribute to a clean energy future.
Rare earth metals face supply chain risk
Rare earth elements are a group of 17 metals, also classified as critical mineralsconsidered essential to the country’s economy or security.
Despite their name, rare earth elements are not that rare. They occur in many places on the planet, but in small quantities mixed with other minerals, which makes them expensive complex to separate and refine.
China controls about 70% of global rare earth production and almost all refining capacity. This near-monopoly gives the Chinese government the power to influence prices, export policies and access to rare earths. China has used that power in trade disputes not until 2025.
The United States, which currently imports about 80% of the rare earth elements it uses, sees Chinese control of these crucial minerals as a risk and has find domestic sources A national priority.
Although the US Geological Survey has mapping potential locations for the extraction of rare earth elements, from exploration to production takes years. That’s why unconventional sourcessuch as extracting rare earth metals from acid mine waste, are attracting interest.
Turning a mine waste problem into a solution
Acid mine drainage occurs when sulfide minerals, such as pyrite, are exposed to air during mining. This produces sulfuric acid, which then dissolves heavy metals such as copper, lead and mercury from the surrounding rock. The metals end up in groundwater and creeks, where iron in the mixture gives the water an orange color.
Expensive treatment systems can neutralize the acid, with the dissolved metals settling in an orange sludge in treatment ponds.
For decades, that sludge was treated as hazardous waste and transported to landfills. But scientists of University of West Virginia and the National Energy Technology Laboratory have found that it contains concentrations of rare earth elements comparable to those found in mined ores. These elements are also easier to extract from acidic mine waste because the acidic water does already released them of the surrounding rock.
Experiments have shown how the metals can be extracted: Researchers collected sludge, separated out rare earth elements using water-safe chemistry, and then returned the cleaner water to nearby streams.
It’s like mining without digging, turning something harmful into a useful resource. If this process is scaled up, this is possible lower cleaning costscreating local jobs and strengthening America’s supply of materials needed for renewable energy and high-tech manufacturing.
But there’s a problem: who owns the recovered minerals?
The ownership question
Traditional mining law covers underground minerals, not minerals extracted from water that naturally drains from abandoned mine sites.
Nonprofit watershed groups that treat mine waste to clean the water often receive public funding intended solely for environmental cleanup. If these groups start selling recovered rare earths, they could generate revenue for more cleanup projects, but they also risk violating grant terms or nonprofit rules.
To better understand the policy challenges, we have surveyed mine water treatment companies through Pennsylvania and West Virginia. Most treatment systems were governed by landowner agreements in which operators had no permanent property rights. Most operators said “ownership uncertainty” was one of the biggest barriers to investment in rare earth recovery. cost millions of dollars.
Not surprisingly, water treatment companies that owned the land where the treatment took place were much more likely to be interested in mining rare earths.
West Virginia has taken steps in 2022 to boost rare earth recovery, innovation and acid mine drainage cleanup. A new law gives ownership of recovered rare earth elements to whoever extracts them. So far, the law has not been applied to large-scale projects.
Across the border, Pennsylvania Environment Good Samaritan Act protects volunteers who treat mine water from liability, but says nothing about ownership.
This difference is important. Clear rules like those in West Virginia provide more certainty, while the lack of guidance in Pennsylvania can leave businesses and nonprofits hesitant about undertaking expensive recovery projects. Among the treatment workers we surveyed, interest in rare earth extraction was twice as high in West Virginia as in Pennsylvania.
The economics of waste to value
Recovering rare earth elements from mine water will not replace conventional mining. The quantities available at drainage sites are much smaller than those produced by large mines, even though the concentration can be just as high, and the technology to extract them from mine tailings is still developing.
Still, using mine waste offers a promising way to supplement the supply of rare earths from a domestic source and help offset the environmental costs of cleaning up contaminated streams.
Early studies suggest that recovering rare earths using technologies currently being developed could be profitable, especially if the projects also recover additional critical materials, such as cobalt and manganese, used in industrial processes and batteries. Extraction methods Are also improvemaking the process safer, cleaner and cheaper.
Government incentivesresearch funding and public-private partnerships could accelerate this progress subsidies support fossil fuel extraction and solar and wind energy have helped scale up electricity supply.
Treating acid mine drainage and extracting its valuable rare earth elements offers a way to turn pollution into prosperity. Creating policies that clarify ownership, invest in research, and support responsible recovery could ensure that Appalachian communities benefit from this new chapter, one in which cleanup and clean energy move forward together.
Hélène nguemgaing is an assistant clinical professor of critical resources and sustainability analytics at New York University University of Maryland.
Alan Collins is a professor of natural resource economics at New York University University of West Virginia.
This article is republished from The conversation under a Creative Commons license. Read the original article.
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