Brazilian iron ore miner Vale has proposed that "ore-sands" generated through mining waste could be a solution to both the environmental impacts of mine tailings and a sand deficit affecting the construction and aggregates markets.

Vale last month released the results of a 12-month research project it has conducted jointly with the Universities of Queensland (UQ) and of Geneva (UNIGE) that studied how materials previously discarded as mine waste can be repurposed for sand use on a vast, global scale.

Vale's focus on tailing solutions is driven in part by its desire to heal the legacy of the tragic tailings dam disaster in Brumadinho, Brazil on January 25, 2019, which led to 270 fatalities.

The study released in April found that in addition to easing complex storage issues, that mine waste could be a solution to spiraling demand for sand, gravel and crushed rock. This demand has tripled over the last two decades to reach an estimated 50 billion tons per year, according to the UN.

Mining Magazine discussed the initiative with Emile Scheepers, leader - Customer Solutions (Europe & MENA Emile Scheepers, leader - Customer Solutions (Europe & MENA) at Vale, and Pascal Peduzzi, Professor, Department F.-A. Forel for environmental and aquatic sciences, University of Geneva. 

 

 

MM: Emile, how did you first come around to this concept of using ore sands to generate materials that can be then marketed to aggregates and construction companies?

ES: Well, we have to go back about nine years, to when I started my executive MBA here in Switzerland. They asked all the participants to generate a business idea that had value for them, and you had to pitch it. That was quite a nervous and competitive week, but at the end of it, I managed to convince four professionals to join me. The business idea at that time was just to take the sandy parts from mining residue and produce quartz surface or engineers stone, which is kind of a substitute for granite and marble.

Where did the idea come from? Well that time, people were trying to study the use of tailings. But as the report now outlines very well, there was a lot of stops and starts for various reasons. When I had looked at tailings, I thought, ‘well, it really looks a hell of a lot like sand', if you just look at it from a particular lens. That's really how it came about. I finished off the business plan, and it looked good on paper. And this then came back into the Vale ecosystem around 2015.

At that point, it started to interact with other little islands within Vale itself, where people had like-minded ideas, to switch from tailings to sand, which helped us to start talking about ‘sand' inside the company (the phrase "ore sand" was first coined in the report itself). We started to interact, and it built on itself to become something a little bigger and broader.

 

It wasn't easy at the start to sell the idea internally, that we have to produce sand, and using existing iron ore assets. That was a really difficult sell at the beginning.

However, when around that time, a report from UNEP authored by my fellow interviewee today (Pascal) came out in 2014, called ‘Sand: Rarer than one thinks', and this really provided us with a two-step solution for the same problem.

The message was important - it was saying that ‘sand is not unlimited. So watch out, it has a societal impact if you just keep on extracting it from everywhere around the world'.

And our solution of generating sand product from tailings could not only limit the amount of mining tailings, but also be a solution for the impending crisis of sand. And at that point, it became a simple, somewhat easier sell. But it took a few more years until it became a business concept of environment. 

Pascal, what kind of problem does this solution address? And what is the scope of the issue that we're dealing with here?

PP: Well, when I started to study the issue of sand and sustainability, I was quite surprised that no one was monitoring this - because when you look around you, everything is built with sand and gravel.

So this is about concrete, land reclamation, walls, windows, and even the computer screen we're looking at is made of sand. The chips behind the computers are made of sand.

So sand is literally everywhere. And all developments are based on sand. How would you make schools, health facilities, roads, dams, bridges without gravel? And no one was really monitoring this, because everyone took sand for granted.

On this planet, nothing is infinite, we might have a huge amount at one stage, but not necessarily forever. Or sometimes you have the resource but you already built a city on top of it. Perhaps it is near a forest or water supply and then you are in colliding with other interests.

So this is why we can see that because of population growth, because of migration from rural areas to urban areas - and because of catching up on development for all the facilities and infrastructure as I was mentioning - there is a tremendous demand for sand.

Then in 2014, I started to estimate what this amounts to, because there is a quite linear correlation between the use of sand and use of cement, it's about 10 to one. So we identified that about 50 billion tonnes per year of sand was needed for the entire world. And this is basically enough to build a 27-by-27 meter wall, all around Planet Earth every single year. So that's the amount we talking about.

Now you cannot withdraw 50 billion tonnes of sand from the environment without having a large impact. So this may impact on biodiversity, on fisheries or tourism - when you take it out of the beaches. Or on floods and drought through river erosion.

People are mostly drawing sand out of quarries, which is actually the best way you can deal with it, because it's easy to manage this.

But when people are taking it out of rivers, or out of the beach - out of the marine environment - the sand is not static but in a dynamic state. It interacts with the environment and removing it causes a lot of problems.

When you start to have environmental problems, the social problems just follow. So if you kill fish, then the fishermen are out of jobs, if you're removing the sand from the beaches, the people, the women who are collecting the crabs are out of jobs.

So the more I was studying this, the more impact I saw all around the world, and I saw that no one was really addressing that.

There is an emotional connection between people and sand, and the press attention to my report went wild - I got so many requests from journalists, I gave more than 100 interviews, and they were all asking, ‘OK, now you've you've identified those problems, what are you what is your organization doing?'

 

And well, we had to do something. So I organised an expert roundtable and Emile was there, with many other experts. There are several potential solutions, for instance, you can reduce waste. You can recycle the material when you demolish a building, you can recover it from waste that you're burning - there is bottom ash that you can use - or you can make better regulations, to reduce, recycle, recover.

But when you're talking about 50 billion tonnes, you need something that is the same volume. That's about replacing it with something, and we were looking for an industry dealing with such a huge amount of material, the answer is very obvious - mining.

The mining industry is the only one dealing with the huge amounts of material, we estimate tailings waste for instance to be between 30 and 60 billion tonnes per year.

So when we considered Emile's idea, we thought, even though Vale is huge, imagine if we can connect the entire mining industry. Then we might have a solution that reaches the same huge numbers in terms of a sand deficit.

MM: Can just take tailings or waste for any mine and use it to produce sand? Could you explain the process?

ES: I'm talking here principally about the iron ore mining industry. This is where Vale largely operates. We also have other business interests (like Nickel etc.), but from mining from an iron ore mining perspective. Keep in mind that the 30-60 billion that Pascal was referring to, includes the entire mining industry.

From an iron ore perspective, ore sand does not come from the tailings as it comes out of a particular beneficiation unit. We do this inside the current existing iron ore beneficiation assets.

So if we take the example cited in in the report, at Brucutu, our largest beneficiation plant in Brazil. So, the steps inside that particular beneficiation unit look a lot like all other iron ore mining facilities in the world. That are trying, we are enriching the primary product, which is iron ore, so it would typically have crushing, grinding, it would have magnetic separation, it would have flotation and some kind of cyclone system. All of that to break down the pieces and then to separate the good bits in this case, iron ore.

The tailings would then all from all these different stages would then be put together and you would get tailings going to a system.

This secret, which is not really a big secret is we looked at this and we said we're almost there. You know, ‘we're almost there', we just have to go inside the beneficiation facility and then look at some particular off-streams, the residues, the larger fractions.

And we saw they have serious amounts of silica in them, which I know is not the definition of sand. But it's mostly the one associated with up to 85%-90% of these big fractions. So we were almost there, we just didn't have that last stream, that last button, with which we can control what comes out as a co-product - as ore sand.

It's not as easy as I make it sound, but we put in a hydro cyclone. And we put another filtration unit, just to make sure that we are now not at the behest of the control functions around iron ore, and we just let the ore sand happen. So we have a slight control and variability that now comes out of this existing iron ore asset. That's why the investments were relatively low that we made. So now we have a stream coming out that we can sort of control. And if you, if you call it a product, which we believe it is, you've got to have control.

And when you will take this control into commercial contracts, we've got to guarantee a little bit of stable variability so that it can be applied in various industries.

So to summarise, I think it was relatively easy to physically do it. But it can be a challenge to convince all the others around it that it was worth doing.

And here we are, and in terms of volumes, and just to give you a flavour. So last year, at the Brucutu site, we produced 250,000 tonnes. This year, we're looking at around 1 million tonnes of ore, sand product in itself 80% of that is going to sales and 20% of donations. And up to 2023, we're looking to create 2-3 million tonnes.

Now these are no not at all the volumes mentioned above, around the use of aggregates and sands. But this is a good first step. We're just one company and we hope we can help show other industries that if you find local demand and you have a local solution, then we can do our bit.

MM: And in terms of like adoption for aggregates or construction companies looking towards this solution as a potential source of sand. Do you see any challenges or barriers that it might face?

PP: Well, that was part of the project as well - looking at the market. So we actually also would like to stress that it was a fantastic collaboration because Vale gave us full freedom to do the research the way we wanted to.

We were able to do the sampling independently, making sure that we have a variety of samples that were representative.

And then we were testing with the University of Queensland's Sustainable Minerals Institute - both the process and then when trying to look for the markets.

There are different markets. When the product is very fine, we can mix it with coarser material to blend it and get it fit for the purpose of building - for concrete. But we also get processes where we could refine it further and get the purity to get to the 99.5%-99.7% silica sand that opens the door for getting into the glass market.

We were trying to find different niches for the sand because you can always use sand for filtration, but when you want better value - options like glass one brings this.

We wanted to test the niches and then we looked through interviews, to look at the ‘why', some people were reluctant to use leftovers from the mining. In this case, we are talking about the resource. and that's why we changed the name and we tried to find a name that was clean, ore sands.

The sand we are talking here about is a material that is very similar to natural sand - it does not contain any toxic material and it is really fit for the purpose.  We want to get away from the idea that it is mining waste - because most people would have a bad perception about it.

And it's true that some mining activities might create toxic waste. And in this case, that's why we need to do the study the clinical analysis. In that specific case, the material is very clean, and can be really used without toxicity.

So the idea of these interviews was to get the perceptions of the market. And for the market they have no problem with using ore sands, they just don't want to have the work to do on the certification.

They would like the countries to adopt the policies, the standards, so that they don't have to worry with all these things. Getting standards and certification is a costly process.

As long as this is taken care of, and testing and the legal and policy framework are in place, they are more than open to it, because they're always looking for new products.

It is also important to remember that it's getting difficult in some locations to get the right product at the right price.

You want to have a resource that is close to your business. It isn't easy to move this huge amount of material. Too far, is too costly. Actually, mining industries are present in many different places close to where we are building infrastructure.

MM: That's great to hear. And I think that was really one of the fascinating aspects of the report to me that the sort of mapping and modelling work that you've done, where mines are and the proximity and the sheer scalability of the solution. So why does Vale have this strong focus on tailing solutions?

ES: I would say it is at the very heart of everything we do right now. Of course, we will never forget what happened. And that is one of the drivers that keeps us pushing to find healing solutions. When it comes to specifically ore sands and this project, it is just one of a menu of solutions that we are looking into. For example, filtering and dry stacking is a very large part of what Vale is doing. We're spending about US$2.4 billion over four years to make that happen.

Another big investment and commitment that we've made is in dry concentration processes. So around 2018 Vale obtained dry processing technology, so that means we don't need to use water to make the product and to obtain quality iron ore.

This particular effort where we are generating ore sand through the existing iron ore assets is another part of that. But the main driver with this project is to find sustainable alternatives for something that would otherwise have no economic value.

And our focus now remains on talking to the market. Exactly like Pascal says, on having a larger adoption of this ore sand that maybe has a strange waste connotation to it.

What was really exciting, really exciting about this collaboration is that while Vale is busy on the ground, finding are always in Brazil, where we live, and where we where we engage with communities - this could also potentially have a huge, global-scale impact.

As we said, it is important to engage with governments on norms and regulations, because some are about 50 years old. We have proven that in many cases it's technically okay to use solutions like this but need assistance from the top down with regulatory authorities, to make it an easier path for something that is already technical by. These are exciting times, and at the same time, we're on the ground, trying to make adoption easier for the customer.