Mining is a polluting business. Can new tech make it cleaner?

In March, President Joe Biden directed increased federal resources toward mining metals and minerals used in electric vehicle (EV) batteries, such as nickel, cobalt, graphite, and lithium, in March. The presidential mandate brought to light one of the most contentious facts at the heart of the green energy transition: we need more mining—a historically polluting industry—in order to move from dirty fossil fuel energy sources to carbon-free renewables and electric vehicles.

Mining is the process of extracting ore from the earth, transporting it to processing plants, crushing it, sorting and purifying the metals, and finally discarding the rubbish. Mines and related infrastructure take a lot of energy and water, pollute the air, and generate hazardous waste, therefore land is stripped bare to make place for them.

However, a slew of new technologies, ranging from artificial intelligence to carbon capture, may make extraction of the so-called essential minerals and metals needed for the energy transition more sustainable than it is now. With demand for these materials projected to rise as the globe shifts away from fossil fuels and toward solar, wind, and electric vehicles, both the US government and the commercial sector are becoming increasingly interested in bringing innovative technologies to market as rapidly as possible. The Department of Energy (DOE) stressed the necessity of federal assistance for "environmentally sustainable and next-generation" key mineral extraction technologies in a recent study on bolstering supply chains in the United States for the clean energy transition.

According to Douglas Hollett, a senior advisor on critical minerals and materials at the DOE, this underscores the agency's belief that critical minerals mining cannot simply be a question of discovering and digging up the resources we need.

“It’s: Let’s find it, let’s be more effective at it, and let’s end up with the lowest targeted impacts across the value chain, as we look at everything from the exploration phase to extraction, processing, then end of life,” Hollett adds when the products mined resources are used in no longer work.

Mining data

Geologists are deployed into the field to drill holes in the earth and look for lucrative mineral reserves long before a mine is developed. Exploration is usually the least ecologically detrimental step of mining, although it might be better. A small but rising number of mineral exploration businesses believe data mining may help them do so.

KoBold Metals, for example, employs advanced data science methods and artificial intelligence to explore enormous volumes of public and historical data, as well as data collected during AI-guided field programs, for indications of battery metal deposits. KoBold, which is backed by Bill Gates' Breakthrough Energy Ventures, seeks to increase discovery rates 20-fold over typical field exploration efforts while also lowering the amount of land that has to be disturbed in order to uncover new ore deposits.

KoBold's mission is "achievable," according to Holly Bridgwater, an exploratory geologist at Unearthed, an Australian geosciences innovation company: Geologists believe that only around one out of every 100 mining locations is ever developed.

This summer, KoBold is doing research in Canada and Zambia, where it has discovered indications of nickel and cobalt resources. Josh Goldman, the company's chief technical officer, believes it will take "two years or more" to decide if any of them are worth mining. If AI can be used to find well-hidden but exceptionally high-quality ores, Goldman believes that mining's downstream effects will be reduced.

“If you find low-quality resources, you have to mine a huge amount more material” to extract the metal, Goldman explains. “That means you have a huge amount of additional waste. Finding the really high-quality resources is critical.”

Powering renewably

Although finding higher-quality ores may minimize mining's environmental impact, any typical mining operation would still have substantial environmental consequences, notably in terms of climate change. The mining industry consumes 6% of worldwide energy consumption and produces 22% of global industrial emissions. While many mining businesses have started purchasing renewable energy and others are experimenting with alternative transportation, such as hydrogen-powered trucks, the industry still heavily relies on fossil fuels to operate its heavy gear and energy-intensive buildings.

There might be a better way ahead for at least one key mineral, lithium. Lithium, which is used as an energy carrier in batteries that power everything from smartphones to electric vehicles, may see a 40-fold increase in demand by 2040 if the world moves fast from gas-powered to electric vehicles.

For decades, scientists have studied the prospect of extracting lithium from geothermal brines, which are hot, mineral-rich liquids brought to the surface from deep inside the Earth to generate electricity. According to Michael Whittaker, a research scientist at the DOE's Lawrence Berkeley National Laboratory's Lithium Resource Research and Innovation Center, the goal is to use carbon-free geothermal energy to power the whole lithium extraction process. Removing lithium from geothermal brines might also save a lot of water compared to the massive open-air evaporation ponds used to extract lithium from the shallower mineral-rich waters under Argentina and Chile's salt flats.

Before considerable amounts of lithium can be recovered by the geothermal method, many obstacles must be overcome. In comparison to their South American equivalents, the lithium level in geothermal brines is "relatively low," according to Whittaker. Other elements, like as sodium and potassium, tend to be present in considerably larger amounts in geothermal brines, interfering with lithium extraction. Currently, geothermal plant operators send heated brine to the surface and inject the used brine back down far quicker than lithium can be collected, according to Whittaker, limiting the utility of the process.

Despite technical and commercial obstacles, the DOE and business sector partners believe the geothermal technique has promise. Rough estimations based on brine chemistry and volume imply that a vast quantity of lithium lies hidden beneath the Salton Sea, a hyper-salty lake in Southern California.

“No matter how you slice it, there’s a lot of lithium [beneath the Salton Sea] that could potentially supply the U.S. demand for batteries for EVs for the rest of the decade,” Whittaker adds. “And probably many decades thereafter.”

Mining waste

Some experts and entrepreneurs believe that the resources required for the energy transition can be found in aged and abandoned mining waste.

Nth Cycle, for example, has created technology for extracting battery metals like cobalt, nickel, and manganese from mine waste, low-grade ores, and end-of-life technology like EV batteries from mine waste, low-grade ores, and end-of-life technology like EV batteries. Its main process, known as "electro-extraction," requires neither harsh chemicals or high-heat furnaces like those used in mining and recycling operations, instead relying solely on electricity, which may be generated from renewable sources. Metals are carefully extracted from crushed, liquified rock by passing it through a succession of electrified, carbon-based filters, which Megan O'Connor, the company's creator and CEO, compares to enormous Brita water filters.

Nth Cycle's 300-square-foot filtering systems can be carried to mining locations, according to O'Connor, who perfected the metals extraction process while earning her PhD and before starting the firm in 2017. According to corporate data, they can extract up to 95 percent of the residual metals from waste material. The business hopes to announce its first mining clients later this year after raising $12.5 million in a fundraising round in February 2022.

The DOE has been researching whether rare earth elements, a collection of chemically reactive metallic elements used in offshore wind turbines, electric vehicles, and semiconductors, may be extracted from coal mine waste, such as coal ash, for than a decade. The government announced plans in February to build a $140 million extraction and separation plant to test the concept on a commercial scale. The study, according to Hollett, is a "exciting" opportunity to examine if the hundreds of coal waste sites in desperate need of cleanup may also yield something useful.

“Whether it’s a legacy ash pond or a stubbornly persistent acid mine drainage situation, it goes in the direction of being able to address resources from existing legacy materials,” Hollett adds. “But there’s a remediation theme here as well.”

Deep decarbonization

After miners have removed all of the valuable minerals from rocks, the poisonous waste, known as tailings, is generally buried on-site. However, if the mining was done on specific types of rocks—so-called ultramafic rocks, which have a high magnesium concentration and high alkalinity—those tailings have the ability to absorb carbon from the air.

“What happens in the ultramafic mine tailings we work on is that they consume CO2 from the atmosphere, and they put that CO2 in a solid mineral form,” explains Greg Dipple, a geology professor at the University of British Columbia. “These are the most durable and permanent form of carbon storage.”

According to Dipple's research, ultramafic mining tailings may absorb tens of thousands of tons of CO2 each year on their own. However, he claims that simple, low-cost interventions such as spinning the tailings to expose new rock to the air and adding or removing water from this powdered debris may improve the process by a factor of three or four. Dipple believes that when combined with renewable energy and hydrogen or electric cars, this type of carbon capture has the potential to make some mines carbon-negative, meaning they remove more CO2 from the atmosphere than they create.

Dipple and a group of collaborators created Carbin Minerals in 2021 to commercialize their idea. Carbin Minerals, which focuses on forming partnerships with nickel miners operating in ultramafic rocks, is now in talks with a number of mines. Elon Musk's XPRIZE Carbon Removal program identified the business as one of 15 milestone winners in April. All of the winning teams had to show that their technology could remove billions of tons of CO2 from the atmosphere. Dipple claims that Carbin Minerals' $1 million reward will assist speed early-stage research into applying its method to a wider spectrum of rocks.

“Together with the anticipated growth in the supply chain required for critical and battery metals, that’s the pathway to this technique potentially working at a scale of billions of tons a year,” Dipple says.

‘As sustainable as we can be’

While new technologies provide promise for more ecologically friendly mining in the future, many are still years away from being implemented on a big commercial scale—if that is ever conceivable. To lessen the need for future mining, we must do a far better job of recycling metals from dead solar panels, EV batteries, and other technology. Finally, tougher rules and regulations are needed to guarantee that mining is expanded with the permission of local people and in a fashion that benefits those areas directly.

While mining's effects will never be zero, Bridgwater believes the sector can and should do far better.

“Fundamentally, mining is about extracting materials,” Bridgwater explains. “There’s always going to be energy required to do that; there’s always going to be some form of footprint. Our goal should be ‘as sustainable as we possibly can be.’”
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