HxGN RadioPodcast

Sustainable mining: Nearing net-zero

Making mines more sustainable is an integral part of transforming the earth’s, and humanity’s, future. In this episode of HxGN Radio, we examine innovative sustainability initiatives, including efforts to manage and create value from waste. 

BK: Welcome to HxGN Radio. My name is Brian, and in today’s podcast, we’re discussing sustainability and mining. The technologies and resources required for building a sustainable future rely on mined materials. Despite mining’s historic reputation, the opportunity exists to not only make operations more sustainable, but to be in an integral part of the effort to transform the earth’s and humanity’s future. 

Colorado School of Mines professor, Dr. Priscilla Nelson, is joining me to talk about some of the innovation, the innovative initiatives supporting the industry’s sustainable future. Dr. Nelson, thank you for joining me, appreciate it.

PN: Oh, my pleasure. Always happy to visit.

BK: Well, it’s good to hear or it’s good to meet you actually, and it’s good to be in person. I love this. And so, I want to know a little bit about you. So, tell us about yourself and what you do and what you’re currently nerding out on and passionate about right now?

PN: So, I’m a person who has moved around a lot. You might know what tenure is in the academic world? Well, I’ve resigned tenure three times so far.

BK: Nice.

PN: I keep moving to other positions, but not for the location, rather for the opportunity.

BK: Nice.

PN: So, in 2014, there was an opportunity to come to Colorado School of Mines and to become the department head. And I’m not a mining engineer, but I thought, “What the heck?” So, I showed up and I was department head, stepped down just before COVID hit. And I looked around to see what was next on the agenda, what was important. I wanted to stay in the mining industry, but I think the most important thing affecting the mining industry right now is tailings and mine waste and mine water management. So, I went head over heels into that, took a deep dive, learning everything again from geotechnical engineering on, and now I’m going around trying to solve problems related to tailings management. That’s my passion at the moment.

BK: I love that. So very curious, always looking for a new opportunity and then diving in, going full board.

PN: Yeah. That’s me.

BK: I love that. Perfect. All right. Well, let’s get a little philosophical then to start things. Let’s talk about sustainability and mining. But for context, can mining be sustainable, going with what you’re talking about?

PN: Well, people talk about sustainable mining, and I never think I know what they mean. I always ask what they mean because it’s never clear. To me, the two better words to associate are stewardship of the earth’s resources and responsibility, and you’ll hear very often about responsible mining. So, I think that reconciling the terms, sustainability and mining is not a question of stopping mining. That’s not the purpose, but it’s rather how to maximise the environmental, social and economic benefits, and then at the same time minimise the extraction rates, so that we do not exceed the capabilities to produce or overrun the resources that exist for future generations. So, it’s a different sense of the stewardship, but the stewardship is very clear. And I think you extend the framework for understanding mining from what is now very often the emphasis on environmental and social footprint of mining operations today and how we can improve that, how we can make problems of today go away.

But with transitioning I think, to really a responsible management of mineral resources throughout their entire life cycle, that includes the use, and it includes end of life, and it includes recycling. So, there is a demand in my mind for mining to become part of that continuous materials flow instead of sitting outside of it, kicking in raw materials when somebody wants to buy them. So, it’s a real change in philosophy, and I think it’s incredibly important. And I think if people haven’t read about Doughnut Economics, which is a book that was written by Kate Raworth from the UK, she’s an economist. She pretty much laid out the concept of the way we have to become sustainable in the world as if you think about the world and you think about where we live in a doughnut.

Now, the hole in the centre of the doughnut represents the social boundary, the basics that everybody on the globe should have. Clean water, the ability to say whatever they want, access to energy and information, all of that is the centre of the doughnut. The outside of the doughnut is the planetary boundary and that deals with climate change, it deals with ozone, it deals with biodiversity, it is the planet. And so, we humans and our enterprises exist in the dough of the doughnut. So, this is a closed system. And now, we start thinking about sustainable growth. How do you do sustainable growth when you have a finite doughnut? And so, you get sub doughnuts. In developing countries, we have sub doughnuts where you have a mining enterprise. It is working with the local community. It is working with the environment. It’s existing on that world. And they ask themselves, “How am I sustaining people so that they don’t fall into the doughnut hole?” And “How am I avoiding conflicting with the planetary boundary in my world?”

The City of Amsterdam has made its plans forward trying to make Amsterdam a responsible doughnut, so that everyone who lives in Amsterdam has the basic social functions and Amsterdam itself, and its enterprises does not impact on the planet, which is really neat. So, I think that the basic sense of what the developed countries need to be doing is thinking about the big doughnut, because the developing countries aren’t thinking about the big doughnut.

BK: Sure.

PN: But the Western countries, the developed countries have a responsibility to really think about the big doughnut, think about not just the life cycle of the mine operation that they’re working on, but the whole life cycle of the mined material and that’s a very important responsibility and it deals more with government governance than it does corporate governance.

BK: Okay.

PN: So, it’s very interesting days these days.

BK: Yeah. Well, I really love the paradigm shift as far as the definition from sustainability to stewardship and responsibility, I think that’s a really, really good way to put it. I’m curious though with the small doughnut impact, do you happen to know… On some level what that impact is, it’s not the large doughnut impact, but it’s the small doughnut impact?

PN: Yeah. I think it’s what most people do with their lives. They have their life, and they have to make their decisions about running their household and running their family. And that’s the focus of the small doughnut. So, we have a mining operation that exists in one valley that has a certain watershed, that has a certain climate, that has a certain community nearby and that’s the focus of it. That’s appropriate. But there has to be this big doughnut that we have to realise. And we may be able to grow the doughnut if we are extremely good at providing social fundamental functions, so the doughnut hole gets smaller and smaller. And as we understand the planetary boundaries more, so that if we really understand about climate change and really understand what’s going on with the atmosphere and the water balance and everything else, renewables. If we really understand those things, we may with confidence be able to grow the doughnut because we understand how to not infringe upon the integrity of the planetary boundary.

BK: Absolutely.

PN: So, that makes the science of earth systems important – do we really understand them? And that’s what we need to work on.

BK: Yup, absolutely.

PN: So, that’s why we have academe involved in this because those questions have to be continued to be addressed.

BK: Absolutely. Well, it’s good it’s being talked about. So, not only managing waste, but what kind of a value can come from that?

PN: Yeah. Well, I think that the issue of waste is only getting more critical. Just to hit it very hard, the grade on many ore bodies is going down, so the volume of waste is going up and it’s going to go up for the foreseeable future. And that’s separate from the critical minerals drive, which is going to be increasing mining to create those materials. But the mining enterprise generally is focused on mining. Most mining companies want to mine, that’s what they want to do. They don’t want to deal with mine waste. They don’t want to deal with tailings. So, how do we change that thinking? Their responsibility and interests are not just economic (and perish the thought only focusing on net present value, which does not look at the long-term considerations of mine operation). We need to get the mining companies to think about more, the responsibility for downstream applications.

And so, we have some companies like LKAB in Sweden, that’s working with Boliden to really make a situation where waste product from Boliden can go over to LKAB like pyrite concentrate and then turn it into sulphuric acid and phosphates for fertiliser. So, you really have the industrial ecology where the waste from one process is the food for another process. And there’s a responsibility if you think about that.

BK: Absolutely.

PN: So, now we have to think about, “All right, we produce a whole lot of tailings. What can that be the feed for?” And right now, there’s people doing quite a bit of work, entrepreneurs trying to figure out what’s going on, what can you do with tailings? Vale Iron down in Brazil, has been separating sand size grains out of their tailings and selling it for construction material, right? The sand size grains are mostly silica, quartz, 99% pure, and they want to get to the four nines purity because then it can become feed for solar cell development. So now, they are interested in research that will get that last bit of haematite out of the quartz. You have people who are trying to make civil construction materials out of mine waste. But the value is relatively low.

So, as long as we stay on economic value, we’re going to be limited by what we can do. I, myself want to melt the tailings and pull fibres, which can be used to make composites, but that’s never going to be the bulk of the tailings. So, I think we have to start to understand tailings and the value that we’re talking about differently from just economic. So, we have to figure out how to have a value associated with environment and a value associated with social. And these really cannot be quantified very easily, and they cannot have a dollar value put on them.

With blockchain following what goes on with the waste and with the products, we start seeing that there is a component in the blockchain record that records the environmental damage or undamaged that was done in the production. Material efficiency becomes important and the social justice and benefits distribution, all the people do they have access to the information? Have they gained from the fact that mining is there? All of this wraps up into the concept of green premiums and we’re seeing the start of a market that is a green premium market, whether it’s aluminium that S&P Global has been tracking for the green premium, or you have Tesla wanting to buy green nickel. So, we’re in a period of transition where we’re going away from purely an economic valorisation to a more fully dimensional valorisation that really is in tune with sustainability and the UN’s SDGs, sustainable development goals.

BK: Good. Yeah. It’s a very interesting discussion and I’m glad it’s moving in the right direction. Now, what are some of the promising initiatives happening right now when it comes to making the industry more sustainable, or even saying making the industry better stewards? I guess we could say that too.

PN: Well, I think LKAB in Sweden has a complete philosophy, they want to produce zero waste. Everything that they produce for mining, they wish it to become the feed stock for something. And people are doing that, not just as a matter of convenience, but a matter of moral obligation. This is all part of staying in the doughnut that you have to do. I think renewable energy is becoming very accessible and much less expensive. So, we’re getting to the point where energy becomes less of a cost, and it always was one of the highest costs of mining was energy, but as we get renewables… That’s great. But the renewables that people are thinking of requiring batteries or requiring to be a part of the grid. We have to run transmission lines. And so, that’s not the best thing and the battery drive is what’s driving the critical minerals, the lithium and the cobalt and the nickel and everything else.

So, you think about alternative ways of storing that energy onsite rather than batteries. Something like compressed air energy storage, which could be developed on site, you can make the energy from renewables and actually store the energy on site in compressed air energy, whether it’s an underground vault or some of the technologies that NASA has been developing for storage of hydrogen and oxygen as fuels after you split water. They’ve got some really remarkable technologies that have only been inside of NASA. Now, we’ve got to pull it out.

BK: Yeah. Yeah, exactly.

PN: So, the idea of in reaching into NASA and doing that. I think IOT has been increasing efficiencies with maintenance and robotics and operation. Enhanced productivity is one of the main outputs, but also safety, removal of people from unsafe conditions and risk reduction overall. The potential of knowing more about what we’re doing, so we can make better decisions in the future is very important. I think with waste management, one of the biggest problems is driven by the presence of water in the tailings. And the water is required because it’s a requirement of mineral processing. So, most of the geometallurgy flow from the ore body down to the tailings passes through hydrometallurgy, some flotation process. So, we’ve got water in the tailings and it’s easy to pump slurry. So, that’s good too.

But when you get to the end of the pipe, you have a problem because you need to get the water out of the tailings. So, we’re seeing some experiments go on where we actually apply electrokinetics, where instead of waiting for gravity to be the driver of getting the water out of the tailings, you actually put an electric field and drive the water out with a totally different gradient system. There’s been an experiment that was done in the oil sands up in Canada about that. And in Australia, they’re setting up for an experiment of that. There’s been some work done in Chile on that. And I think we’re ready to go to really scale up from these bench scale tests to pilots, to really looking at what if you do that in an existing tailings pond and try to drive the water out, because when you drive the water out, you get to recycle it and the tailings material becomes stronger. So, that if the tailings facility fails such as Brumadinho did in 2019, the tailings material behind it is strong enough to not flow.

And then, we have to start learning about what a stable geology looks like when we try to have closure. So, that’s the end of life. How do we do that? And in an era of trying to deal with climate change, which we don’t really know what climate change means on that small doughnut scale of a mine operation. How do we know that we can make a stable landform for geologic time? It’s very interesting days, these.

BK: Yeah, there really are. And so, you’re doing things like this, obviously, within an academic standpoint, obviously with Colorado School of Mines. So, you’re working on this. Are there any other things like that you’re trying to push that you haven’t already shared?

PN: We need to do some more fundamental work on what is called, dry stacking on filtered materials, because we built the Brumadinho Dam, and all the dams that have failed, we built. And we don’t know how, when we place the material, we create the conditions for static liquefaction. And right now, people are thinking of filtration and dry stacking as the silver bullet that will solve everything, but it won’t. I think we have a lack of knowledge on the long-term performance of those materials, and we don’t know what’s going to happen when we get higher and higher and higher. We’ve been building for a hundred years earth embankment dams to retain water. The tallest one is less than 100 metres. We have tailings dams that are 300 metres high, 500 metres high. The stresses caused by that height, we do not know how the material will behave in the short term or the long term.

So, there’s some fundamental research that needs to be done. And I think also since you brought up the academic question, the situation that we have here, after the Brumadinho failure in 2019, there was an outcry from many sectors associated with mining and it resulted in the mining community getting together and defining the Global Industry Standard for Tailings Management called, the GISTM. That document was produced in 2020 and in conjunction with ICMM which is the international council. Right now, the entire mining industry is trying to figure out how to implement and how to demonstrate implementation or conformance with the GISTM which is huge. And what the GISTM says effectively is that we need an order of magnitude more engineers and qualified people to work with mine waste. We don’t have those people.

So, the pressure comes back on academe to say, “Okay, develop the programmes, recruit the students.” And as you said at the start, we have a perceived reputation in mining. We have to change that reputation and really make it so that students first choice on coming to college is to say, “I want to be a steward of the Earth’s resource. I’m going to study mining.”

BK: Yeah. Absolutely.

PN: And then, we have a pipeline where we have the undergraduates going out with internships, getting experience, deciding they want to get a master’s degree in tailings and mine waste management and a PhD. So, we have more professors who can produce more students. All of that requires research money. The mining industry is not the strongest supporter of fundamental research. Getting the message to the mining companies, that if they want to be able to come to our universities and recruit the people they need, they have to support us over the longer term so that we can make the pipeline.

BK: Absolutely.

PN: And that includes research and includes graduate studies and that includes producing faculty. So, if they do that, we can do it.

BK: Yes.

PN: But if they don’t do it, we’re going to be struggling.

BK: Yeah. Have there been any wake-up calls, pivotal moments, catalyst moments that have caused things in the industry to become like, “We need to be more sustainable,” or has it just been this, “Well, we’ll get there eventually, and we got to convince them sort of thing.” What’s going on?

PN: So, maybe the flow of growth of responsibility has been more of a staccato. I think it’s been gradually ramping up, but to me it was like 1969, we landed on the moon, and we saw the earth as a blue marble, right? And then shortly thereafter, the EPA was founded. All of these sequences of things led to mining companies, which historically had not been paying much attention to the tailings, suddenly having to pay attention to the tailings. In the ’70s and then the ’80s and ’90s, people were paying attention and really building… starting to build a new profession, which is not the same thing as civil engineering, it is tailings and mine waste management, and tailings are not the same thing as soils. So, when that happened, things were improving but failures continued and the Brumadinho 2019 failure came after three other failures that surprised people in Canada, surprised people in Australia, unexpected failures that everybody sat up and said, “Hmm, there’s things that we don’t know about our way of managing tailings.” So, that was-

BK: That’s good though.

PN: … a real strong boost. But I also think we have wars. That will really give a wake up on critical minerals, which is driving a lot of things right now. But then, we have the creeping things of climate change and the energy transition possibilities, critical minerals, the politics of national resources. Mexico, nationalised the lithium resources, and the rise in the importance of SDGs and ESG, right? Environmental, social and governance issues. So, this is something where there’s a new language out there, it’s in the boardrooms being talked about in the mining companies, whereas it was not five years ago.

BK: Okay. So, that’s positive. So, optimistically though there are some good things going on. That’s good. Okay. So, what are your overall thoughts then on the industry as far as from an optimistic standpoint and also from a concern standpoint?

PN: Okay. I think regarding optimism, the economics are high. People are after metal so it’s time to do things. It’s easy access, easy every day to get energy and to get it in a green sense. And people are appreciating that green premium. So, I think that will drive good behaviour. We have the GISTM and ESG that are drivers of the change, and that is what’s going to change the people’s perception of the mining industry to being a steward and really a responsible… a partner in all of this. So, I think there’s a lot of reasons to be very excited, but I think we still, as a concern, we don’t really understand the climate change crisis and we don’t know where the trigger is and what triggers are. Water scarcity is more and more prominent. So, that is a pressure and a concern. Getting skilled people into the workforce is a major problem.

BK: Yeah. Definitely.

PN: Increase in tailings volume, and that resource nationalism question. But I think right now in the United States, a lot of the focus is on the length of time that it takes to get a new mine under operation. Permitting is 10 years, 15 years from finding to developing, and this will not work the way we do it to have critical minerals development in the time that we need. So, we really have to look at our policies and the regulations to figure out exactly what is needed to protect that planetary boundary and try to minimise the time lost.

BK: Absolutely. Well, where can we go to learn more, by the way. Just getting that more information, learn all about it.

PN: Well, we, Colorado School of Mines in conjunction with the University of Arizona and Colorado State University, have formed the Tailings Centre, which is a research centre, which has been offering professional development short courses for the industry and getting people registered from all around the world. So, you can take those courses. But we’re also planning next year on launching a master’s and a PhD programme in tailings engineering and management.

BK: Very nice.

PN: So, we intend to become the resource, the go to place. If people have questions, if people want to try things out, come and talk with us because we’re there for you.

BK: Excellent. Well, it’s going in the right direction finally, which is great. So, Dr. Nelson, thank you very much. Appreciate all of this and I appreciate your work in what you’re doing and thank you for taking the time.

PN: Thank you very much.

BK: Dr. Priscilla Nelson, Colorado School of Mines professor. Thank you so much for joining us here on HxGN Radio. To learn more and also listen to additional HxGN Radio episodes, head on over to iTunes, Spotify and SoundCloud, and you can visit hxgnspotlight.com, for more stories from Hexagon and for more information. Thank you again for listening and have a wonderful day.