Mining digs into the circular economy

After the Western Australian government announced in June that it was beginning to “decarbonise” the state, research teams from the mining industry and academia began preparing for some groundbreaking collaborations.

Western Australian Nickel Mine

At Curtin, Professor Michael Hitch is leading the first step of the process: drafting the “decarbonization roadmap”, which he wants to align with “circular economy” models.

Hitch, who directs the Curtin WA School of Mines: Minerals, Energy and Chemical Engineering, believes in the resource sector’s ability and motivation to set new standards in the reduce-reuse-recycle circular production model.

“It’s a crucial alternative to the linear model we’re used to, which is make, then use, then discard,” he explains.

“In the circular model we produce, we use, but we never really dispose of. Or we do it in such a way that the manufactured goods can be dismantled and returned to the production flow.”

For a mining company, supporting a circular model includes minimizing the impact of mining operations on land, converting mining waste into useful by-products, and conducting post-mining land remediation. And it is the waste from mineral extraction that is driving the industry’s entry into the circular economy.

“In mining – and in the resource sector in general – we produce a lot of waste. We call it ‘waste’, but really it’s just crushed rock that is disposed of either in landfills or in tailings ponds. In the circular model, we aim to upgrade this waste to the point where a usable by-product is created.”

Flowchart showing the difference between linear economy and circular economy.

“Circular mode is usually quite static with little room for economic growth. However, upgrading waste can actually help an economy grow, and on occasion we may even develop by-products that are worth more than the materials that create that waste.”

“Metal leasing” is another bold concept that Hitch believes has value.

“Basically, it’s blockchain and supply chain management that tracks that ton of ore throughout its lifecycle. The person using the steel to make a product doesn’t buy it, they rent it within a circular economy. When the product has reached the end of its life, it can be returned to the manufacturer or miner as a recyclable material.”

What do artificial reefs, blueberries and color have in common?

The development of useful mining and smelting by-products is fast becoming a global research movement. The focus is on the commitment of everyone 27 members of the International Council on Mining and Metals to a goal of Net-zero greenhouse gas emissions by 2050. Some companies have already taken initiatives to achieve the goal; novelty energy, BHP and Anglo-American, for example, recycle discarded dump truck tires into oil and steel. And Rio Tinto, which is targeting a 50% reduction in emissions by 2030 – in just eight years – is moving forward Blueberry fertilizer made from aluminum waste.

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Photograph of bunches of blueberries on green shrub.

One of Hitch’s research priorities was the potential for the mining by-product selenium to be a fertilizer booster. He has also contributed to research carbonized steel slag to create artificial reefs. But the area he is most passionate about is carbon capture and sequestration (CCS).

“BHP is currently investigating the potential uses for their tailings, which are the material left behind after extraction of the target mineral. In nickel mining, the tailings are essentially sand and chemically neutral. But when it comes into contact with carbon dioxide, the sandy material reacts and the sand particles turn into carbonate,” he explains.

“Because the carbonate is thermodynamically stable for about 100,000 years, it gives sand residues potential as a carbon sequestration and storage material. This would qualify the process for carbon credits.

The material could also form the basis for new industrial products such as building materials, animal feed, food fillers or paint thickeners. In fact, this year alone, Hitch has co-authored three research papers examining the potential of overburden and steel slag as the basis for new construction materials.

“So there are at least three major benefits that nickel residues provide: CO sequestration2, generate CO2 credits and form a basis for innovative industrial products. It is a perfect example of circular economy, where waste has economic value, environmental value and social value.”

Don’t forget your social license

trailer hitch joined Curtin in 2020 after 20 years of industry experience, Starting out as a field geologist, he transitioned into mining operations and eventually research.

“Since the beginning of my career in the mid-’80s, I’ve traveled extensively and seen the good, the bad, and the ugly of what mining can do,” he says.

Photograph of Professor Michael Hitch, a man in his fifties, wearing glasses and a lilac shirt.He stresses that acceptance of a company’s activities in the community is vital to the future of the industry and that mining companies must acquire and maintain their ‘social operating licence’, a concept which is the basis of a magazine paper Hitch co-author in 2021.

“ThisSocial License to Operate or SLO, is about a trust formed between a mining company or another industrial company – it could be a shoe factory. It’s about involving the community in the planning process and operations and being honest in communication and transparent in operations – even when things go wrong.”

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“It needs to encompass community engagement, including what to do with the land after mining operations have ceased and a clear commitment to regulations.”

He says The concept of a social license is often absent in developing countries, where mining companies pay taxes and royalties directly to corrupt governments and where mining assets are not distributed to local communities. Canada, and to a lesser extent Australia, has some of the highest environmental standards in the world.

“Canadian mining companies operating abroad to work are subject to the standards of Canadian law and policy. So if they go in and misbehave, they will be held accountable by Canadian standards. For example, a few years ago, Barrick Gold’s operations in Chile were halted by the Canadian government over concerns about the impact on local water supplies.”

And here in Australia, who could forget the unforgivable blasting of the Juukan Gorge that is still there stigmatizing Rio Tinto?

“In fact, the ‘big end of town,’ as they call it here in WA, does a really good job,” says Hitch. “They create programs and have specialists focused on sustainability and social responsibility so that local communities are not negatively impacted and preferably benefit from the operation.”

What does sustainability even mean?

The circular model is underpinned by the assumption that despite the mining industry’s gigantic contribution to CO2 emissions, mining will remain an integral part of most economies for the foreseeable future. This is not only due to the continued demand for products that use traditional mineral resources for building materials, but also the increasing need for critical minerals that support modern devices and technological innovations.

But what will mining operations look like in the future given the growing call for more sustainable practices?

“Sustainability as a concept has fallen apart a bit,” says Hitch. “We understand ‘sustainability’ as a way of doing what we do without sacrificing the needs of future generations. But there’s another part that a lot of people don’t want to acknowledge — and that’s when it does makeable.”

Citing a mining conference where Indian Prime Minister Narendra Modi revealed that 40% of India’s population was living without electricity, Hitch believes the challenges facing developing countries deserve more attention.

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“Luckily for WA, we produce most of the material needed for the infrastructure of the future – iron ore and specialty metals like nickel and lithium. But whyWe also have a wealth of mining technology and knowledge, and we should export that knowledge to help lift nations out of poverty, facilitate their energy transitions and minimize environmental impact,” he explains.

“But we have to come up with alternative models of the materials we make. Sustainable use of resources is about mining to meet demand, not mining that is economically valuable due to market conditions.

“Ideally, we could estimate how much steel the world will need in the next 25 years and develop mines that would provide the iron ore for the next 25 years of steel production. It’s ‘material responsibility’”.

Mining becomes part of the solution

As part of WA’s decarbonization plan and with support from the Minerals Research Institute of Western Australia, Hitch will develop a research program that offers exciting collaborations for the state’s mining industry.

For example, Ono project GoalsTo develop methods that accelerate the natural process of mineral carbonization, a natural rock weathering process in which CO2 binds to minerals in the earth’s crust and thus removes CO2 from the atmosphere, albeit slowly. The project builds on one of the Hitch’s recent international collaboration investigated the sequestration method for commercialization based on the potential of mineral carbonation to provide greater storage capacity than other CCS methods such as geological and oceanic sequestration.

“Again, nickel residues are ideally suited for this purpose and we are working with BHP Nickel West on methods to increase the carbonation reaction to store CO2 into its residues.”

If successful, the outcome of the project will be a new solution for large-scale CO storage2 -Emissions at the gigatonne scale. And since WA holds about 30% of the world’s nickel reserves and nickel is highly desirable for electric vehicle batteries, Hitch says that “WA could capture more emissions than we produce — and set a new level of innovation in the mining industry.”

“At the end of the day, it’s about resource utilization and management. As we dig into the land, we should find ways to extract value from whatever we take out of the ground, including waste material that previously had no economic value.

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