Jef Caers, Professor of Earth & Planetary Sciences at Stanford, on the future of critical minerals, how to mine sustainably, and the importance of social licensing when drilling.
Notes on the human nature of the earth’s subsurface.
It could be said that Jef Caers is an expert in decision making under uncertainty. In the mining industry that this Stanford geologist studies, success is often less about knowing exactly where copper and lithium are than it is about proving where these critical elements are not.
Grasping this riddle about the earth’s crust may unlock sustainable mining and decarbonization more generally since a clean energy-enabled future will inevitably be built on a foundation of mining. Electric engines, wind turbines, even semiconductors are all architected on the continued availability of ample iron, copper, cadmium, boron, nickel, and other minerals. But how humankind mines is fraught, as Professor Caers explains. It is an industry wrestling with both the toxic legacy of historical mining techniques and the persistently unstable nature of extraction. More efficient and less damaging techniques must be adopted to keep pace with the modern world.
As more companies like Ideon join Professor Caers’ Mineral-X research community, it is clear his ideas about mineral deposits are fast becoming industry-defining. Though, the puzzles of the earth’s subsurface don’t stop with the uncertainty principle that he explains so well. Rather, as Professor Caers told Atoms & Bits, the missing piece in designing a 21st Century extraction regime for what is buried below our feet may well reside in the hearts and minds of non-experts the world over.
This interview has been edited for clarity.
A&B: Tell us about your current research.
Jef Caers: I’ve always been passionate about combining data science with physics, chemistry, and geoscience. Now 25 years into my career, I’m more interested in the human dimension of what I study. I’m an engineer by training, but I realized recently that we can’t just rely on a technological revolution alone; there also has to be a human revolution. Over the last year, I’ve started looking at the human impact of critical minerals, mining, and the energy transition. It’s a generational opportunity. But only if we look at the problems creatively.
A&B: How did the human dimension change your work?
Jef Caers: Writing programs and developing AI to accelerate the energy transition is a lot of what I do. These technologies and algorithms are extremely important. But so is empowering people on the ground to ensure the energy transition is successful. Education is how we empower the people in countries like Zambia — home to one of the largest copper resources in the world — to understand geology, geophysics, data science, and AI and then help make this essential transition.
A&B: It's like the biblical parable — teach a man to fish.
Jef Caers: We need to unite fields of study when it comes to the discovery of critical minerals. You can always persuade a professor of geology and a professor of statistics. But how do you get people to talk to one another and collaborate to solve real world problems? Traditional education is divided into silos. I’ve always been at the intersection of these silos. People used to ask me, “Are you an engineer or are you a scientist?” And I was like, “Well, I don't know, I’d have to figure that out.”
A&B: Can you talk a little bit about how critical element discovery was done up until now and what the future might look like?
Jef Caers: Originally, discovery was done in the field with a hammer. Explorers would look for outcrops to understand the whole system and how it was formed. From that, they would deduce the potential for a deposit. After some guessing, they would drill, move, and drill again until they hit payload. The challenge today is that most of the outcropping deposits have been discovered. A major copper deposit hasn’t been uncovered in over two decades. Miners have only a one in 200 chance of finding something today.
A&B: How do we address these failings?
Jef Caers: By reducing the amount of time it takes to get to discovery and reducing the number of false positives. Finding the more challenging deposits requires a number of fields to come together — from specialized geophysics to artificial intelligence to remote sensing techniques. Companies are coming up with novel ideas around how to image the subsurface. Often a lot of things look promising but end up being nothing. So the challenge now is how to use sophisticated geophysics and AI to decide where to drill. Hopefully that speeds the whole process up to save money and reduce the impact on the environment.
A&B: The reduced impact is due to being more tactical about where to drill?
Jef Caers: Yes, absolutely. In mining, you are always attempting to reduce uncertainty. That’s a particular mindset. When an explorer is on the ground, they want to confirm their ideas. But with so many false positives in exploration, you almost have to use a different philosophy and say, “I’m going to try to falsify the fact that there’s a deposit here.” You have to reverse your mindset and prove there’s nothing there. That allows you to walk away quicker from something that’s not either there or economical, as opposed to chasing something that’s really not there, and you keep investing money into it. And it's very common for humans to say, “I already invested so much money in this thing. I want to keep investing more money into it.” But you should actually walk away.
A&B: The sunk cost fallacy.
Jef Caers: Exactly. When you start out with a goal of reducing uncertainty, you're now in a whole new realm of ideas well suited for artificial intelligence. The AI techniques we use allow us to reduce uncertainty as quickly as possible. We can design predictable tests that instruct whether to walk away or go ahead and mine. These technologies are unlocking a viewpoint that is completely new to the industry. Mining companies traditionally don’t work that way. They don’t like to walk away.
A&B: Tell us more about this new viewpoint.
Jef Caers: Building misses into a mining paradigm allows for more efficiency and success. It’s an idea that comes from Karl Popper, an English philosopher and writer, who argued that you can’t confirm a theory; you can only falsify it with experiments. That’s true in mining as well. But it’s a hard mentality to sell to companies, because exploration, mining, and supply chains aren’t integrated. Explorers sell what they find to mining companies who sell to the market, and so on. There is no one entity making a decision. Often it takes one entity making a decision about everything to actually adopt this Popper falsification philosophy.
A&B: What are some of the best ways of falsifying?
Jef Caers: Typically, explorers make a geological hypothesis about the subsurface. They then use that leading hypothesis to reduce uncertainty. Accomplishing a more certain outcome, however, requires excellent data. In the 1970s, the oil industry could use seismic exploration by passing sound waves through the subsurface to bounce off oil deposits. That let them see deposits on a map. The mining industry has never had that kind of technology. Mining deposits are different from oil and gas deposits in that they are usually found in very hard rock. You can’t image it well. Companies like Ideon have come up with ways of mapping the subsurface using muons and cosmic rays. These rays spread themselves evenly in the subsurface and change based on what material they pass through. Companies can then detect and measure them through boreholes to get a 3D image of the subsurface. And if that 3D-image is similar to a geologist’s hypothesis, then falsification can happen quickly.
A&B: Is there any other way to do it?
Jef Caers: The alternative is a guess and check method with countless boreholes. It’s like using one finger to look for raisins in a bowl of pudding. You can be right next to a raisin and have no idea where to find it. Without full 3D visualization of what’s below the surface, falsification is painfully slow.
A&B: In lieu of a falsified result, what does a good 3D visualization look like?
Jef Caers: A nickel sulfide deposit looks like a wine glass. At the bottom of the wine glass is the quarry. What happens is that these massive sulfides sink into the bottom of this geologic chamber. You need to know the shape of this chamber and you need to know that there’s something a little more dense at the bottom. You have to be able to 3D image the wine glass and see that it has the right shape or a shape conducive to the right deposit.
A&B: Critical elements have their own geometries.
Jef Caers: Yes, but there are many types of deposits. Massive sulfide deposits contain nickel sulfide, copper sulfide, or cobalt sulfide. Those are important, because they are highly concentrated and high grade. Which means mining them will use less water, energy, and land. I tell everybody that the energy transition and decarbonisation of the mining industry will depend on the grade of the deposits that we find as much as the number of them. With high grade deposits, we can mine laparoscopically or telescopically. These sulfide deposits have approximately 4% nickel in them, which doesn’t sound like a lot. But nickel found in soils in the rainforest, which are called nickel laterite deposits, contain only 0.3% nickel. So you need to scrape off the entire top soil and then process it and make an open pit mine to get a result. While nickel sulfide can be mined completely underground, you wouldn’t even see there’s a mine — just a building on top of the earth. All to say, exploration is not just about more; it’s also about higher quality. Otherwise, we’re going to just keep ruining neighborhoods, planets, and communities.
A&B: When you say a critical element, what are we talking about?
Jef Caers: So there are the major elements like copper for electrification and lithium, nickel, and cobalt for batteries. And then there are smaller elements called rare earth metals. They’re not actually rare; they are just hard to extract from the rock because they’re always in small concentrations. But they are everywhere. Rare earth metals are used in a number of applications such as magnets. They’re also critical for the energy transition.
A&B: It seems like the most advantageous mining methods are the most sustainable.
Jef Caers: That is true, but technology can only get us so far when it comes to sustainability. On decarbonization, open pit mines don’t look pretty but carbon dioxide emissions don’t track the aesthetics. Copper mining produces around 80 million tons of carbon dioxide emissions, while oil and gas production creates around five billion tons of CO2. So yes, we have to look at decarbonizing the mining industry. But it’s a drop in the bucket relative to other critical industries.
A&B: How does the mining industry reach sustainability?
Jef Caers: What is most important is the social license to build sustainability into the global mining system. Take illegal mining, which is a big issue across multiple continents. In Brazil, mining companies build roads into the rainforests and artisanal miners follow that infrastructure. Gold is mined in Brazil with mercury, so now 20% of the kids born in the rainforests have mercury in their brain. Not to mention the ecological effects. All of these consequences are due to the illegal mining that trails legal mining. So solutions need to take on a systems-level approach. We cannot rely on a company-by-company strategy. A company can do everything right, but children could be digging the same vein just down the road. Local governments need to be empowered and communities need a say in how and what technology is deployed.
A&B: Who is responsible for thinking systematically?
Jef Caers: AI can be abused, misused, cause misinformation, or empower. So who regulates that? Is it Facebook, Google, OpenAI, or the U.S. government? It’s an unanswered question. We face the same dilemma in mining. Companies are responsible on the ground and many believe they can regulate themselves. But that is far from the truth. I believe it should be a collaboration between government, industry, and local organizations that work with the communities most affected by the mining. Together, those entities can decide on land and water use, how to deal with contamination, drainage, and so on. It has to be a collaboration.
A&B: Is the U.S. government a leading light on this front?
Jef Caers: Sadly, there is no social license to operate in the United States. People don’t want mining in their backyard, so permitting takes forever. Each government organization in the process imposes an enormous cost. There’s also no education about the importance of critical elements or investment in mining. We are spending $1 billion on critical minerals and materials, but China spent $10 billion this year alone. If we don't invest, then we won’t have our own supply chain, which means we will be more beholden to non-democratic states.
A&B: So better mining is essential for American competitiveness as well?
Jef Caers: Yes. We do have great allies. Australia is responsible for more than half of the world’s production of lithium. In the short-term, we need to work with our allies like Australia and Chile to make sure the supply chain is strong. Then over the next five to 10 years, we will have to rethink permitting and investment in extraction.
A&B: What is social licensing?
Jef Caers: Social licensing is about collaborative community where you consider questions like “What is the impact?” and “How can we invest in this community?” It's a term from sociology. In the United States, 75% of critical minerals are on indigenous lands. So mining operations have to consider what extraction means for them. Canada and Australia had been working with indigenous communities for years, but not always successfully. I don’t think much of that is happening in the United States. A good example is the Salton Sea, where there is such a large lithium deposit there that the area is called “Lithium Valley.” But little engagement goes on between the extractors and local communities. I know because we had people from Salton Sea communities on the Stanford campus who were complaining about how mining leaves behind an industrial wasteland with toxic tailings and infrastructure rusting in the desert. We have to build towards win-wins.
A&B: It sounds like companies can ease a lot of the pain around these conversations.
Jef Caers: Yes, but there has to be some more regulation, too. In many parts of the world, mining companies hold half-an-hour presentations, and that’s it. But these conversations need to be long-term and held over years. People don’t trust extractors right off the bat. You have to build trust.
A&B: Battery-dependent companies like automobile manufacturers are buying into mines. Is that a good trend?
Jef Caers: There is a public image problem with batteries. Car companies don’t want to say, “This battery was mined by children in the Congo.” That’s not good business. It’s not good for mining companies either, but they are still able to sell their product to other businesses all the same. The fact that car companies are taking ownership interests in critical element mines means that the communities who live near those mines may have a louder voice and a better opportunity to affect the extraction process. It means more sustainable practices and efficient mining methods may become more popular.
A&B: Where are the other opportunities in mining?
Jef Caers: We need more reliable data and information. Data in sociology is a huge problem. A bunch of statisticians called Data Colada recently scrutinized the social sciences and found fraud everywhere. So we need better data to understand and apply it elsewhere. The social sciences have to be somewhat quantitative and reproducible.
A&B: What inspires you?
Jef Caers: What inspires me is this latest generation of students. They’re coming in with climate sensitivity. They want to do more than technology; they want to get engaged in the social aspects of things. That’s new in the last five years. I would never have had students say, “I want to work with you, and I want to go in the field to talk about education.” You can feel their passion boiling up. And when you talk about AI and neural networks, you can’t leave out how to make a difference.
A&B: That is a broad mandate for an engineering student.
Jef Caers: Most of my PhD candidates take on a technical topic, like 3D imaging and interpretation of data. But they also work on social topics. One of my students is in Zambia near the Democratic Republic of the Congo working with kids and asking them, “What do you worry about?” They are engaging about water, mining, education, all of it. More mining companies are realizing that taking ownership of these mines is a good business model. That way they can engage and give back. Maybe that means helping train local engineers to help compete with foreign engineers or running scholarship programs. Regardless, it’s the right thing to do — to give back.
A&B: The human element seems inseparable from the actual geophysics.
Jef Caers: If you’re a company imaging an ore body and your technique is really good, that place is going to become a mine. That’s a lot of power to wield.
A&B: Thank you, Professor.
