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

In March, President Joe Biden ordered more federal resources geared toward mining the minerals and minerals needed for electric car batteries, including nickel, cobalt, graphite and lithium. A presidential directive has highlighted one of the most controversial facts at the center of the green energy transition: In order to shift from dirty fossil fuel energy sources to zero-carbon renewables and electric vehicles, we need more mining — historically a highly polluting business.

Mining involves excavating ore from the ground, transporting it to processing plants, crushing it, separating and purifying the minerals, and then disposing of the waste. The land is stripped to make way for mines and surrounding infrastructure, which often use large amounts of energy and water, produce air pollution, and produce hazardous waste.

But a host of emerging technologies, from artificial intelligence to carbon capture, could make the extraction of the so-called critical minerals and minerals needed for this energy transition more sustainable than it is today. With demand for these materials expected to increase as the world moves away from fossil fuels and embraces solar, wind, and electric vehicles, there is growing interest from both the US government and the private sector to bring new technologies to market quickly. In a recent report on US supply chain support for the clean energy transition, the Department of Energy (DOE) emphasized the importance of federal support for “environmentally sustainable, next generation” extraction methods for critical minerals.

This reflects the agency’s view that mining critical minerals cannot simply be a matter of finding and prospecting for the resources we need, says Douglas Howlett, the Department of Energy’s special advisor on critical minerals and materials.

“It’s: Let’s find it, let’s be more efficient at it, and let’s end up with the least targeted impacts across the value chain, where we’re looking at everything from exploration to extraction to processing and then end-of-life,” when Howlett says the products used in mined don’t work yet right Now.

mining data

Long before the mine is built, geologists are sent to the field to dig holes in the ground and search for valuable ore deposits. Exploration is usually the least environmentally damaging phase of mining, but there is still room for improvement. A small but growing number of mineral exploration startups believe they can do so with mining data.

These startups include KoBold Metals, which uses sophisticated data science and artificial intelligence tools to search for evidence of battery metal deposits in vast amounts of public and historical data, as well as data the company collects during AI-guided field programs. KoBold, with support from Bill Gates’ Breakthrough Energy Ventures, aims to boost discovery rates 20 times over traditional field exploration efforts, reducing the amount of land that has to be bothered to find new ore bodies.

Holly Bridgewater, an exploration geologist at the Australian Geoscience Innovation Corporation, thinks Kobold’s goal is “achievable” given the mining sector’s very poor hit rate: Today, geologists estimate that less than 1 in 100 sites surveyed for mining actually become a private site. with me.

Kobold is doing fieldwork this summer at several sites in Canada and Zambia where it has found evidence of nickel and cobalt deposits. But chief technology officer Josh Goldman says the company has “two years or more” to decide if any are worth mining. Goldman says that if he can use AI to discover well-hidden but particularly high-quality ores, it could reduce the impacts of mining.

“If you find low-quality resources, you have to extract a large amount of material” to extract the mineral, Goldman says. “That means you have a huge amount of extra waste. Finding really high-quality resources is critical.”

Renewable energy

The discovery of high-quality ores can reduce the impact of mining, but any conventional mining operation will still have significant environmental impacts – particularly on the climate. Pulling, crushing, and processing rocks is energy intensive; The mining sector accounts for 6 percent of global energy demand and 22 percent of global industrial emissions. While many mining companies have started buying renewable electricity and some are experimenting with alternative means of transportation such as hydrogen-powered trucks, the sector is still largely dependent on fossil fuels to power heavy machinery and energy-hungry utilities.

For at least one metal, lithium, there may be a cleaner path forward. Used as a powerhouse in batteries that power everything from smartphones to electric vehicles, global demand for lithium could rise more than 40-fold by 2040 if the world quickly switches from gas-powered to electric vehicles.

For decades, researchers have explored the possibility of extracting lithium from geothermal brine — the hot, mineral-rich water that some geothermal power plants bring to the surface from deep within the Earth to produce energy. The idea is to power the entire lithium extraction process with zero-carbon geothermal energy, says Michael Whitaker, research scientist at the Center for Lithium Resources Research and Innovation at the Department of Energy’s Lawrence Berkeley National Laboratory. Removing lithium from geothermal brines also has the potential to use much less water than the huge outdoor evaporation ponds used to concentrate lithium from shallow, mineral-rich waters lurking beneath the salt flats of Argentina and Chile.

Significant hurdles must be overcome before large quantities of lithium can be obtained through the geothermal process. The lithium content in geothermal brines is “relatively low” compared to their South American counterparts, Whitaker says. In geothermal brines, other elements, such as sodium and potassium, tend to be present in much higher concentrations than lithium, which interferes with its extraction. Currently, says Whitaker, geothermal plant operators are bringing hot brine to the surface and injecting the spent brine back underground much faster than they can extract lithium, meaning they are unable to get as much value as possible from the process.

Despite technical challenges and commercial setbacks, the Department of Energy and private sector partners see the geothermal method as promising. Rough estimates based on brine and volume chemistry measurements suggest that a massive amount of lithium lurks beneath a hypersaline lake in southern California known as the Salton Sea.

“No matter how you chop it up, there is a lot of lithium [beneath the Salton Sea] That could supply US demand for electric car batteries for the rest of the decade,” says Whitaker. “And probably many decades after that.”

mining waste

Some researchers and entrepreneurs believe that the resources needed for energy transmission can be found in waste from old and abandoned mines.

This cycle includes Nth Cycle, a startup that has developed technology to extract battery metals such as cobalt, nickel and manganese from mine waste, low-grade ores and end-of-life technology including EV batteries. Its core technology, called “electrical extraction,” doesn’t use any of the harsh chemicals or high-temperature furnaces often found in mining and recycling processes — only electricity, which can come from renewable sources. Minerals are selectively removed from crushed and liquefied rock by running mine waste through a series of electrified carbon-based filters that founder and CEO Megan O’Connor likens to Brita’s giant water filters.

O’Connor, who improved the mineral extraction process while completing her PhD and before founding Nth Cycle in 2017, says the company’s 300-square-foot filtration systems can be moved to mining sites. There, company data shows, they can extract up to 95 percent of the remaining minerals from materials considered waste. The company, which raised $12.5 million in a funding round in February 2022, plans to announce its first mining clients later this year.

For nearly a decade, the Department of Energy has been investigating whether rare earth elements, a group of chemically reactive metallic elements used in offshore wind turbines, electric vehicle engines, and semiconductors, can be harvested from coal mine waste, such as coal ash. In February, the department announced plans to set up a $140 million extraction and separation facility to demonstrate the idea on a commercial scale. Howlett described the project as an “exciting” opportunity to see if hundreds of waste coal sites in desperate need of cleanup could also provide something of value.

“Whether it’s an old ash pool or a stubbornly persistent acid mine drain condition, it’s going in the direction of being able to process resources from existing old materials,” Howlett says. “But there is a therapeutic theme here as well.”

Deep decarbonization

After miners extract everything valuable from the rock, the toxic waste, called tailings, is usually buried at the site. But if the mining process occurs on certain types of rocks – the so-called supermafic rocks, which have a high content of magnesium and high alkalinity – then these residues have the ability to absorb carbon from the air.

“What happens in the ultramafic mine tailings that we’re working on is that they take up carbon dioxide from the atmosphere, and put the carbon dioxide into a solid mineral form,” says University of British Columbia geology professor Greg Dieble. “This is the most permanent and permanent form of carbon storage.”

Dipple’s research shows that ultrafast mine tailings can sequester tens of thousands of tons of carbon dioxide per year on their own. But he says this process can be boosted by a factor of three or four with some relatively simple and low-cost interventions, such as agitating the tailings to expose fresh rock to air and adding or removing water from this powder. Besides using renewable energy and hydrogen or electric vehicles, Diebel thinks this form of carbon capture has the potential to make some mines carbon negative — meaning they pull more carbon dioxide out of the air than they produce.

In 2021, Dibble and several of his colleagues founded Carbin Minerals, a start-up that aims to commercialize their technology. Carbin Minerals, which focuses on partnering with nickel miners working in ultra-resilient rocks, is negotiating partnership agreements with multiple mines. In April, the startup was named one of the 15 outstanding winners of Elon Musk’s XPRIZE decarbonization competition. All the winning teams had to show a track for their technology to pull billions of tons of carbon dioxide out of the air. Dibble says the $1 million Carbine Minerals award will help accelerate early-stage research to use its technology on a wider range of rocks.

“Together with the projected growth in the supply chain required for critical metals and the battery, this is the path to this technology that has the potential to operate on the billion-ton-per-year scale,” Dibble says.

‘As sustainable as possible’

While new technologies offer hope that the mines of the future can be more environmentally sustainable, many are still years away from their widespread commercial application – if at all proven. And cleaner mining methods are just one piece of the puzzle: We also need to do a much better job of recycling minerals from dead solar panels, electric vehicle batteries, and other technologies to reduce the need for mining in the future. Finally, stricter laws and regulations are needed to ensure that wherever mining is expanded to meet the increasing demand for minerals, it is done with the consent of local communities and in a way that directly benefits those communities.

While the impacts of mining will never be zero, Bridgewater says the industry could do much better — and it has a responsibility to try.

“Basically, mining is about extracting materials,” Bridgewater says. “There will always be energy required to do this; there will always be some form of footprinting. Our goal has to be ‘as sustainable as possible’”.

Leave a Comment