We speak with a field geologist and an external affairs specialist from a climate tech company working on a revolutionary method of carbon sequestration that transforms mine waste into carbon-rich rock. Flux-measuring land rovers, flux towers, proprietary algorithms, and field surveys are all helping to maximize the process of terrestrial carbon mineralization at Arca’s pilot study site in Western Australia. Sean and Sam dive into the details of their work, like how to work with local communities, methodology development, and the benefits of climate action.
Transcript
Emma: Arca is a climate tech company founded in 2021 focused on enhanced carbon mineralization. It is part of the Carbon Removal Alliance and the Carbon Business Council. Its first pilot project was launched in late 2023 in Australia. Our first question for both of you is, what is ultramafic rock and what are mine tailings, and how do they capture CO2?
Sam: Ultramafic rocks are rocks that are rich in magnesium. We use the term “mafic” to describe rocks that contain a fair amount of magnesium, so you can just imagine how much magnesium ultramafic rocks have. The beauty about ultramafic rocks is that when they're metamorphosed under high temperatures and pressures deep in the Earth's crust, they form an excellent feedstock for carbon removal. The way this works is magnesium-rich minerals that form after this metamorphism, like serpentine and brucite, dissolve and release the magnesium, which can then bond with aqueous carbonates and precipitate out as magnesium carbonate minerals. This happens naturally when the rocks are exposed at the surface, and it's an important regulator of Earth's carbon cycle over long geological timescales.
Tailings are a great place to start with carbon dioxide removal using these rocks because they're a mining product. And here, the rocks have already been crushed into a powder much finer than even flour. That's a great place to start off that energy has already been put into making all of this surface area on these rocks. The other great thing about tailings is there's a huge amount of it globally. About 3 billion tons of suitable ultramafic tailings are produced by the mining industry each year- billion with a ‘b’. There's a lot of it around. Tailings basically get deposited onto a dam. They're pumped out of the processing facility as a slurry, and they get set down into these very large ponds.
Sean: Maybe I can add some color to what Sam said. I'm not a scientist. I'm not a geologist. So, one of the metaphors that really struck me when I started working with geologists at Arca was the fact that the Earth climate has been driven by this phenomenon, mineralization, for all of its history up into the Anthropocene. So as an example, the Antarctic ice cap was created when the Indian subcontinent crashed into Asia and created the Himalayas. Then over about a million years, which is quite a short amount of time in geological timescales, weathering of the rocks that were pushed up in the formation of the Himalayas cooled the planet enough to form the Antarctic ice cap. This phenomenon can get us out of the climate mess that we're in.
Emma: Maybe for people who don't know, you can explain what smart churning is and how Arca works with that.
Sam: Smart churning is one of the ways that we at Arca can accelerate this natural carbon mineralization by manipulating the surface of these tailings dams. We can expose more of these reactive ultramafic tailings to the air through continuous monitoring of environmental variables, we can choose the right time and place to churn. It's really what puts the smart into smart churning.
To get a bit more specific, we use agricultural implements to churn over the surface of the tailings dam. We have two rovers that can use these agricultural implements and are also fitted with flux monitoring equipment. So, it is an integrated system, churning and monitoring.
Jess: Your system is patented so, there's some details that you can't give us, but it seems like your rovers are heating and shaking and stirring and then waiting.
Sam: Arca has a portfolio of technologies, some of which are still in the lab being developed. Where Sam is working now with the monitoring equipment, the flux chambers, eddy covariance towers, and the rovers, the rovers churn the surface based on information that the monitoring provides so we can maintain an optimal level of mineralization. In the lab here in Vancouver, our scientists are developing activation technology, which involves using microwaves and other ways of blowing apart - a bit like popcorn - blowing apart the mineral lattice structure of the rock. This liberates more magnesium, so it's more available to mineralize with carbon dioxide in the atmosphere. So, this increases both the speed of mineralization as well as the quantity of mineralization that can occur.
We haven’t deployed the microwaves yet. So, what the rovers do is churn, and they also carry monitoring equipment. They are important for a couple of reasons. The tailings are a bit like quicksand, they're very wet. They're deposited in a slurry form when they first come out. They’re dangerous to walk on, so the rovers are amphibious. They can work on water as well as solid material.
Jess: So, it's like a hundred-thousand-dollar Roomba?
Sean: Yeah, and they've all got nicknames.
Sam: We've got Tilly, we've got Eddy…
Emma: So, you're using these rovers, but how are you quantifying CO2 capture & storage and how that might be impacted by environmental factors?
Sam: We use a combination of mobile and stationary flux instruments, namely eddy covariance, and dynamic closed chambers. A lot of the leg work for demonstrating and developing the methodology that we're applying here at the Mount Keith pilot project was done at the University of British Columbia in the lab of Professor Greg Dipple, who is now our Head of Science. A lot of that leg work was done by Marti Doucet, Francis Jones, and others who now work at Arca.
Emma: So, you mentioned, you have these flux systems on these rovers, and they're moving around. That's very different than I think a lot of our listeners might be used to. I'm wondering if you could talk a little bit more about how these things move and what that means for the quantification of carbon.
Sean: I mean, the rovers can carry dynamic closed chambers and eddy covariance towers. Where Sam's working now, we also have installations on the surface of the tailings, where they are dry and solid enough. The towers work over a wider area, I think it's 200 square meters maybe. The chambers are like a spot measurement, so we have many, many chambers and then a few towers. These two instruments, we use them to triangulate the amount of flux, the amount of CO2 that goes into the porewater, and the tailings. So, we can see in almost real time the rate of mineralization. In response to that information, we have proprietary algorithms that help us make sense of all this. Then we send out the rovers to ensure, to maintain, the optimal rate. That is the theory of smart churning. You can measure unambiguously using total inorganic carbon analysis how much carbon dioxide has been mineralized. It's not based on models. It's based on measurement.
Emma: Could you talk more about the team that makes up this company and what kind of companies invest in these carbon credits?
Sam: Yeah, we've got a quite diverse team with people who work on the field team. We've got geologists, we've got environmental scientists, we’ve got soil scientists, we've got process engineers. So, it's quite a diverse mix that we really have to draw in all of those areas of expertise in our day-to-day operations here.
Sean: In Vancouver, geologists, geochemists, chemical engineers. There's a few of us non-scientists who do the other stuff; policy, government relations, fundraising. So, it's not just about the science and technology. It's also about the infrastructure you need in order to commercialize the technology so we can get the resources we need to scale.
Emma: I've noticed, Sean, that you don't call yourself a scientist, and yet you're very articulate. When you describe a lot of these processes. Did you come in knowing a lot of this stuff? Did you have to learn about it to be able to communicate that better to people?
Sean: Well, I've a degree in mechanical engineering from many, many years ago, and then, I spent a lot of time in cross-boundary communication. I've been helping the company since April 2021, so it's…it's been a bit of a crash course in many things; carbon markets, geology, mining, technology development. Carbon dioxide removal didn't exist before a couple of years ago. It's burgeoning. It's forming, as an industry. Those of us who are in this industry, 2000 people, are doing our best to figure it out, so that it will scale.
Emma: Many of us might be interested in knowing more about how this industry came to be, and your relationship with clients and how you build trust with them.
Sean: I mean, I think that people have been aware of the need to remove greenhouse gases from the atmosphere for many decades. Carl Sagan, in the 1970s, was talking about it, and Greg Dipple discovered the phenomenon of carbon mineralization in mine waste over 20 years ago. But, it's really only been in the past couple of years, I mean, since the Paris Climate Agreement in 2016 and then the growing sense of alarm in the scientific community. This is in the IPCC reports now, it's all agreed across the world scientific community that not only do we need to stop emitting greenhouse gases, we need to remove the garbage that we’ve put in the atmosphere if we are to avoid catastrophic tipping points. Our society has been built on a very narrow temperature band.
If, for example, we melt Antarctica. The Antarctic ice cap is great for stability of the world's climate. Our big cities at ocean level, agricultural practices, are based on climactic zones. It's pretty serious. What I find interesting about working with scientists is that they can be very understated. You state the facts, that there's a budget, and you can’t exceed budget. So, 1.5 degrees is kind of not a political target, even though it's often framed as such. It's a scientific limit. If we surpass 1.5 degrees, we surpass a number of Earth system boundaries, and we lose control of the climate of the environment upon which our civilization has been built.
So, carbon dioxide removal is an industry that needs to be scaled so it can remove 10 million tons a year of carbon dioxide by 2050. There are a number of different pathways, a dozen or so different technology pathways. We happen to believe that mineralization is the dark horse: it can remove all of the pre-industrial greenhouse gases and return the Earth's atmosphere to pre-industrial levels. There is enough ultramafic rock, that Sam described, at the near-surface to remove everything. That's very promising. Most of it is buried deep underground and needs to be brought to the surface of the mine, so there are a number of difficult questions need to be addressed. Part of this also is just generating sufficient political will so that the solutions can be taken to scale.
Note: Carl Sagan testified to US Congress in 1985 about the greenhouse effect on Earth.
Emma: Can you talk about some of the other challenges at that intersection of mining and climate tech? The way that Arca is measuring this carbon storage is a little bit different than other companies, using both chambers and eddy covariance fluxes is pretty unique.
Sean: Arca’s approach to measurement is unique. It's unambiguous. This is really important for a couple of reasons. Mining has generally a pretty poor reputation for environmental stewardship. The industry is very sensitive to accusations of greenwashing. We would like to work with the waste products. Mine waste lying at the surface can be a feedstock for removing carbon dioxide from the atmosphere. We'd like to work with the mining industry at scale in these different areas. The mining industry, rightly so, is highly regulated and very visible. And, mining is necessarily very conservative, very cautious. The way mining works is fascinating. It takes maybe 15 to 20, 25 years from discovery of an ore deposit to production. Once the mine is in production, it runs for 20 to 30, 40 years to recoup the millions of dollars that are needed to build the mine in the first place.
Mining is a very slow-moving wheel, and a climate technology company like Arca is a very small, very fast-moving wheel. We're venture-backed, we have investors. That gives us a certain amount of runway, so a certain number of months to run. We need to develop our technology with that investment and take it to market to begin to generate revenue before we run out of money. There's a classic big-wheel small-wheel problem: how do we find gears to get these two wheels to work together, when mining has the responsibility and the luxury of thinking long-term? As a scientific-based company, we're thinking about the climate, trying to be good ancestors, trying to stabilize the climate. That's a long-term thing, but our venture-backed model behooves us, drives us, to produce results in a matter of months. Whereas mining thinks in terms of years, if not decades.
There's a fundamental challenge there of how to get this large, slow-moving wheel to take the risk. We put a lot of emphasis on measurability and verifiability and unambiguity.
Jess: You guys adopted this technology that, it's so accurate it's scary, I guess, for some other climate tech companies to invest in because they're, like, “well, what if the results don't show a positive outcome?”
Sam: The mining industry doesn't do something unless it's very certain that it's going to work, because there is that longer time scale, that slower-moving wheel. We do have that need to make sure that there's a solid case behind it, that it's well verified, that we understand what's going on. So, it’s a natural consequence, I guess, of working with the mining industries, making sure that everything we're doing is watertight.
Jess: What is it like being on site? What are the sites, what are the sounds? Are there explosions happening?
Sam: The site we’re at here is in the western desert areas of Western Australia. The surrounding landscape is low-lying scrub, red earth, typical Australia. It can be very hot at times. In the middle of summer, it can get 45 degrees plus. We can get thunderstorms that come out of nowhere, so it's very variable. Things change a lot. We've got all sorts of animals cruising around. We've got dingos. We've got big lizards, snakes, plenty of flies. In terms of the site itself, it's a massive industrial complex. You drive along the Goldfields Highway, and then all of a sudden, there it is, these massive dumps of rock and you're driving, and it's all lit up like a Christmas tree, the big processing plant and all of that.
We keep going past the site. It comes to the tailings dam. There's not so many people, so many vehicles or pieces of heavy equipment moving around. The size of it definitely makes you feel small. Safety is a very important part of working with mining industry. We need to make sure that that's our number one priority every single day. A number of things are just stock standard in the Australian mining industry, high-vis clothing being one of them. There's many others to make sure that we're safe every single day.
Jess: A lot of the old mines in the United States near the Smoky Mountains have water waste that can sometimes leak out.
Sam: We hear often in the news about tailings dam failures. Often in high-rainfall areas or areas where there’s steep elevation you get these failures of the tailings dams and huge run out of the tailings material. Historically, it's not such an issue here in Australia because it's so flat, but it's definitely still a very important concern for the mining industry, making sure that the tailings dams remain stable. One of the things we are exploring is how the cementation of the tailings particles, how is that affected by carbonation? Can we actually make tailings dams more stable by carbonating these ultramafic mine wastes?
Sean: Arca is a purpose-led company. The purpose of the company is to stabilize the climate. We're using a commercial model to scale that. Eddy covariance is a fantastic way for us to build trust in our stakeholders that we're doing what we're saying we're doing. It was at no-brainer for us to use eddy covariance and chambers from the beginning, because that's how the original phenomenon was discovered and documented. Agriculture, water, oil and gas, mining, cement: There are only a few industries that really move that much material per year. So, if we could nudge this industry in the direction where its work removes carbon dioxide from the atmosphere, then that's a great thing.
The energy transition requires more mining, not less. So, what we hope to do is to be able to help mining produce the things in society needs in a way that does good for the planet; carbon neutral nickle, carbon negative nickle if their energy sources are renewable in some cases. The more certainty we could provide, the more reassurance that we can provide, the easier it will be for them to adopt carbon dioxide removal as part of their operations.
Emma: What types of communications goals are important, to communicate across all these different sectors?
Sean: There's like, 10 different stakeholder groups, so to be able to create a narrative that transcends all these different institutional boundaries and mindsets requires simplicity. We spend a lot of time thinking about narratives and communication tools. We work with communication companies and designers to really focus on how we get across our messages. Sometimes we make mistakes. We show graphs that make sense that geoscientists and completely go over the heads of investors and customers. We learned the hard way. What is it we need to say to this stakeholder group? How do we portray the data in a way that supports that narrative, is the question that we ask ourselves all the time.
Emma: Arca is also working with Indigenous communities in Australia. I am based in Flagstaff, and the mining industry has had big effects on both the Navajo and the Zuni Indigenous communities of the Southwest. Can you talk more about your relationship with Indigenous communities and what Arca is doing to partner with them?
Sean: Arca realizes and accepts that the extractive model that created the climate crisis in the first place won't solve the climate crisis. So, a new way of working is required, one that is equitable, that shares benefits across all the different stakeholder groups. If our purpose is to stabilize the climate and we recognize that the model that created the climate crisis is not going to work, then our purpose will be fulfilled if we're working in a different way. We also recognize that carbon dioxide removal as industry won't scale unless it has legitimacy. Legitimacy includes the support and inclusion and partnership with host communities.
A lot of mining operations, most mining operations, are on Indigenous land. There’s a phrase on our website, “The road to net zero runs through Indigenous lands.” We recognized this very early on, and it's not just a statement of our values or the pragmatic approach to scaling industry. It’s also something that we've done something about. We've been working with a group called the First Nations Major Projects Coalition in Canada. It's a group of 180 First Nations. They worked with us for over a year to develop a way of thinking in our company that will help us create more effective relationships with the those communities. It all starts with building a relationship. That relationship could lead to many different things; jobs, profit sharing, equity stake, and project financing.
Legal framework for working with First Nations, as we call them in Canada, is different than it is in Australia. We work with the Development Partner Institute in Australia. They kind of act as a cultural broker and help us translate our intent, in the ways that we've learned about working with Canadian First Nations, into the Australian context. Any future project that we do on Indigenous land will begin with developing a relationship with the traditional owners. It begins with the geology, of course, we can't work unless the right type of rock exists. But then, once we've discovered the right geology, the next step is to partner with the host community, and then we take it forward.
Emma: You mentioned scaling when you were answering that question, and how Arca is going to do things differently than what has traditionally been done in the history of capitalism. I'm wondering if you could tell us more about what expansion looks like? What are your plans to maximize carbon dioxide removal from the atmosphere?
Sean: We feel a sense of urgency as a company. We are freaked out like everybody else is by the science, and alarmed at the failure of our political leaders to move society in a direction that over 80 percent of all people on earth want it to go. There are studies out in The Guardian newspaper, in UK Today, peer reviews, scientific studies that show between 80-89 of the world's population want their political leaders to make decisions that secure life on Earth. So, we're just as alarmed as everybody else is. There's a movement that's available to us to make sure that we re-direct the ship so that it goes the direction where you know life can be protected. When you talk about our plans, we're always based on the geology. The first thing we do is, we hunt for the right type of feedstock. It's alkaline industrial waste.
Carbon dioxide is acidic and alkaline waste is alkaline. Those things come together and form new crystals. That pulls the carbon dioxide out of the atmosphere. So anywhere where there's a source of alkalinity, you can do things to remove carbon dioxide from the atmosphere.
Sam: It's very dependent on the type of rock that you've got. You've got to have the right type of tailings. It's not just any old waste that can be used for this. If you've got the right rock type, you will capture the carbon dioxide and store it as carbonate minerals. We can see that in our eddy covariance data. You can see that day to day the amount of carbon dioxide that we're capturing.
Jess: What is the rate of CO2 uptake?
Sean: Where we believe we can get to is 30 percent by weight. So, if you have a ton of waste rock, we think we can get 300 kilograms of CO2 stored in there. That's with our other technologies that are still in the lab. Smart churning works on the top surface of the tailings, and that can get to something like 10 percent CO2 by weight. Sam, I'm looking at you to correct me.
Sam: Yeah, it really depends on how much magnesium is available across the tailings dam, but something of that order of magnitude.
Sean: Tailings are quite heterogeneous, surprisingly. Looking at it from Google Maps, it's all one color, but as you get closer, you realize there are different colors and different chemical compositions and minerals. But when we deploy our full suite of technologies in a couple of years, we'll be activating, we'll be blowing apart the tailings and able to get up to 30 by weight. That means that we can work with the billions of tons of waste rock that are produced every year of the right type.
Sam: So, to measure carbonate in the rock, we use the total inorganic carbonate methodology.
Sean: There are things called methodologies and protocols. Methodology is the way that Arca measures and submits evidence to verifiers. That's the carbon dioxide that we've removed through our rovers that accelerate the natural phenomenon, that has actually been removed. So, the equations and the measurement is all specified in our methodology, which was just recently validated against ISO standards. It's very rare thing. Another message for the mining industry, another message for your stakeholders and fluxers, that this methodology has been validated by rigorous standards. It took us two years. We used an independent engineering company to validate our methodology. There are also registries where carbon removals are registered, publicly communicated. Registries have protocols against which they assess and validate all the removal claims by their partners. Registries won't let things go on their record unless they adhere to their protocols.
Jess: Sam, do you have climate anxiety? And, does working in climate tech relieve some of that anxiety for you?
Sam: I definitely have a sense of climate anxiety. I'm originally from a farming background. Everybody that I know in the agricultural industry is aware that we're getting less and less rainfall here in Western Australia. And that's particularly concerning for us because it's a low rainfall, dry, hot part of the world. Climate anxiety has been with me for many years. As I went through University, I was studying all these scientific topics and so on and so forth, but there was really a sense that the purpose was lacking. I wanted to put that knowledge to use for something that would do something at least to mitigate this threat that we're all facing. So, working at Arca, I think every day you really get the sense that what we're doing is taking those steps towards being able to do something on a massive scale to stop the climate crisis.
Emma: Thank you so much for talking to us and being here.
Sam: No worries. Thank you.
Sean: It was a pleasure, and uh, really cool to know that you eddy covariance [scientists], there's a community of you out there. It's really cool.