For the final article from our four-part series on innovation, Steel Thoughts caught up with Filipe Vasconcelos, head of mining innovation in our global R&D team, to hear about the efforts ArcelorMittal is undertaking to embrace circular economy concepts, reduce waste from our mining operations and manage our tailings dams in a safe and sustainable manner.

Mining and innovation are not often closely associated. How much scope is there for new thinking and new techniques in such an old process?

It’s true that the fundamental objective of mining – digging up ore and processing it – hasn’t changed a great deal over the years. But doing it efficiently and safely at industrial scale is a totally different proposition.

In the last 15 years, ArcelorMittal has been at the forefront of a huge amount of innovation in the industry, predominantly in the umbrella of the circular economy. Basically, we are trying to find ways to turn what was once considered waste and transform it into something valuable. In mining, dealing with outputs like tailings and waste has always been seen as a burden. But if you have a circular economy approach, you’re looking to find new applications for these materials. That reduces the company’s footprint and liabilities but also improves revenue and benefits the communities and economies around our operations.

Why are tailings such a concern?

The sheer scale of the tailings is massive. For every tonne of steel produced, we end up with seven tonnes of waste material - tailings, or other by-products. In the past, they’ve often been just left in gigantic piles. Not only do these take up space and but they can be a safety hazard if not properly managed. Often tailings are stored in dams – if they’re not monitored and maintained correctly, they can lead to catastrophic accidents.

What are some of the methods you’re using to make tailings safer and more manageable?

We have several strategies. The first is enhanced monitoring. Our team has developed a tool called iSmart, which provides real-time, online data from our 23 tailings dams at our operations around the world – in countries like Brazil, Canada, and Liberia. We use a combination of sensors, weather stations, satellite images, and drones to monitor things like dam stability, water flow, and vibration. This ensures we can detect potential issues before they escalate.

The second approach is focused on increasing stability. For example, we’ve introduced chemical reagents to help stabilize tailings by removing excess water. Dry stacking, which involves reducing the moisture content of the tailings, is a technique we’re exploring to avoid traditional wet deposition.

The third and most exciting part is finding ways to avoid generating tailings in the first place. This brings us back to the circular economy – finding another use for what we once considered waste. We’re exploring ways to recycle tailings into useful products like cement, concrete, and even solar panel components. The goal is to reduce the overall environmental impact and create economic opportunities for local communities.

Tailings have been a problem for decades. Why has it taken so long to find uses for them?

It’s a question of complexity. The precise make-up of tailings vary widely, even in mines that are only a few kilometres apart. After all, the ore comes from Mother Nature. Each batch has unique properties - finding uses that fit these physical and chemical characteristics takes a lot of research and innovation.

Other considerations are the needs of local industries and communities. For instance, one region may need cement, while another may not. Matching tailings with local requirements is key.

We’ve had success in several regions. In Brazil, we’re working with partners to replace sand in concrete with our tailings; in Canada and Mexico, we’re looking at ways to use tailings in ceramics and cement production. We’re also partnering with universities to explore more advanced applications, such as using tailings in fertilizers or other chemical products.

Carbon emissions are another issue for steel producers. How are circular economy innovations addressing fossil fuel use?

That’s a great question. Carbon is indispensable for steel production, so we’re working on finding alternative sources of carbon that don’t rely on fossil fuels like coal. There are options like charcoal made from sustainable sources or even recycling urban waste. We’re even pushing into an exciting area of research into the use of “black mass” – basically, the carbon graphite extracted from recycled batteries. By developing these alternatives, we can reduce our reliance on coal and make the entire steel production process more sustainable.

The sintering process also generates a lot of emissions. Are there alternatives to that?

Sintering is an important step in preparing iron ore for the blast furnace. However, as you say, it does have an environmental impact via emissions like dust. It’s also very energy intensive. That’s why we’re looking into ‘cold bonding’ which replaces the heat used in the sintering process with chemical agents. This could significantly cut down on CO₂ emissions as it would reduce the need for coal or natural gas. We’re still in the early stages, but the potential is huge, not just for cutting emissions – CO₂ and dust - but also for reducing costs, which is vital given the cost of energy these days.

The circular economy is all about finding value in what was once seen as waste. By adopting this mindset, we can reduce costs, lower emissions, and create new opportunities for local industries. It’s not just about sustainability; it’s about using science and technology to improve our overall efficiency and ensure we leave a better world for future generations.