Phytomining is a term for collecting metals from a type of plants called hyperaccumulators. Hyperaccumulators are rare and unusual plants that can absorb and accumulate very high concentrations of certain metals from the soil, at levels that would be toxic to most plants. They accumulate the metals in their leaves and stems, and for some of these plants, it is possible to harvest, dry and incinerate this biomass to generate high-grade bio-ore.
These plants may have evolved the function of hyperaccumulating metals as a defence mechanism, for example against herbivores or pathogens.
Perhaps one of the best known hyperaccumulator plant species is Pycnandra acuminata (previously known as Sebertia acuminata), a rainforest tree that is endemic to New Caledonia. The high concentration of nickel in the plant’s latex gives it a dramatic blue-green colour.
The vivid blue-green latex from the New Caledonian tree Pycnandra acuminata, which can contain 25% nickel. Image: Dr Antony van der Ent
It was first highlighted in the paper ‘Sebertia acuminata: A Hyperaccumulator of Nickel from New Caledonia’ that was published in the journal Science in August 1976. This paper stated that the nickel content of the plant’s latex was 25.74% on a dry weight basis, which the paper’s authors Jaffré et al said is “easily the highest nickel concentration ever found in living material”.
Another paper published in the journal New Phytologist in March 2018, ‘The discovery of nickel hyperaccumulation in the New Caledonian tree Pycnandra acuminata 40 years on’, noted that the discovery of P. acuminata was a major driver of research over the following decades.
The authors wrote: “In its title, the Science article introduced the word ‘hyperaccumulator’ and the term hyperaccumulation was subsequently established [in a 1977 paper] to denote a plant nickel uptake of > 1000 mg kg−1 in dry tissue. The term was later widened to include other elements normally occurring in only trace concentrations in plant tissue.”
Studies of hyperaccumulators
The (now defunct) US Bureau of Mines ran the first phytomining field trials in Nevada in 1994 using the nickel hyperaccumulator species Streptanthus polygaloides. The trial was run on soil with 0.35% nickel, which is well below the economic cut off for conventional mining techniques, and the results suggested that a yield of 100kg of nickel per hectare could be produced via phytomining, which compared well with the average returns from other crops.
The Centre for Mined Land Rehabilitation (CMLR), part of the University of Queensland’s Sustainable Minerals Institute (SMI), launched the Global Hyperaccumulator Database in 2017. It has compiled data on 721 species of hyperaccumulators, representing 52 families and 130 genera, including species that absorb arsenic, cadmium, chromium, copper, cobalt, lead, manganese, nickel, selenium, thallium, zinc and rare earth elements (REEs).
The database was highlighted in the letter ‘A global database for plants that hyperaccumulate metal and metalloid trace elements’ that was published in New Phytologist in November 2017.
The authors Reeves et al said: “Hyperaccumulator plants are of substantial fundamental interest and practical importance. Hyperaccumulators are exceptional models for fundamental science to understand metal regulation including the physiology of metal uptake, transport and sequestration, as well as evolution and adaptation in extreme environments.”
The majority of the hyperaccumulator species listed in the database – 532 of them – are for nickel. This may reflect the fact that worldwide surface exposure of naturally nickel-enriched ultramafic soils cover more than 3% of the earth’s surface. The authors noted that most reported hyperaccumulator plants hyperaccumulate nickel and occur on ultramafic soils that are naturally enriched in nickel and cobalt, as well as manganese in some cases. They highlighted global centres of distribution for nickel hyperaccumulator plants, including the Mediterranean Region and the tropical ultramafic outcrops in Brazil, Cuba, New Caledonia and Southeast Asia.
Phyllanthus balgooyi, a hyperaccumulator of nickel found in Palawan, Philippines and in Sabah, Malaysian Borneo, that has bright green sap due to concentrations of up to 16% nickel. Image: Dr Antony van der Ent
In August this year, the government of the Australian state of Queensland invested A$1 million (GB£543,400 or US$718,000) into a joint study with the University of Queensland’s SMI that will examine the native plants like selenium weed and a variety of macadamia tree for their phytomining potential. It will also investigate whether the process could be implemented at a large scale and be a sustainable option for mining rare metals and the transition from carbon-fuelled mining.
Professor Peter Erskine, director of CMLR, said: “We’re currently growing plants using metal-rich soil and tailings from around Queensland. Thanks to a previous study conducted by UQ researchers, we know Queensland is home to native plants that have this ability to absorb metal, which are known as hyperaccumulators.
“UQ’s further phytomining research has the potential to unlock a sustainable stream of critical metals, including from mine wastes and tailings, that still hold residual metals of interest. So, in effect, phytomining could turn waste into new resources.”
Farming metals via agromining
Agromining is a term for a variant of phytomining. The chapter ‘The Long Road to Developing Agromining/Phytomining‘ in the book Agromining: Farming for Metals, which is now in its second edition, defines the terms thus:
“While phytomining focuses more on the plant and its potential to extract elements of interest, agromining emphasizes technological processes and their combination (agronomy and metallurgy) to produce commercial compounds. Here… we refer to phytomining for previous research and development activities, and to agromining for more recent ones that consider the entire production of bio-based elements.”
The paper ‘Agromining: Farming for Metals in the Future?’, which was published in the journal Environmental Science & Technology in February 2015, proposed that agromining could create value for local communities during and post-mining. Mining companies should actively support these kinds of projects to improve community sentiment and prosperity. Instead of growing food crops, farmers could grow and periodically harvest ‘metal crops’ using hyperaccumulator plants. They could then harvest the biomass, followed by drying, ashing and processing it to recover target metals.
A flow sheet of bio-ore processing options as discussed in the paper ‘Agromining: Farming for Metals in the Future?’ Major inputs, intermediate products and wastes are indicated. Approximate nickel concentrations of the biomass, bio-ore and products are also indicated
The paper’s authors, van der Ent et al, described the benefits of agromining on low-productivity agricultural soils, targeting ultramafic areas that are large and relatively flat which have low productivity for food production.
They wrote: “Agromining here would be superior to conventional agricultural production, generating better economic returns to farmers. A co-cropping approach might also be possible: for example, in Greece, olive plantations could be intercropped with Alyssum; and in Malaysia, palm oil estates could be intercropped with Phyllanthus.”
The economics of agromining
Based on field trials using nickel hyperaccumulator species, van der Ent et al said they could expect to harvest 5-10t of dry matter per hectare containing 2% nickel, yielding 100-200kg nickel per hectare.
“At 2015 prices of US$15 kg−1, and a potential yield of ≥100 kg Ni ha−1, agromining could become a part of a substantial and integrated income stream for ‘metal farmers’ worth more than most food crops,” they wrote. “By means of comparison, a premium rice crop on fertile ‘normal’ soils makes approximately US$850 per ha−1 year in Indonesia, while Ni phytomining on local ultramafic soils has the potential to make US$1000 ha−1 year.”
They also drew attention to the low economic returns of ultramafic soils for producing food crops such as wheat or rice, due to the inherent infertility of the soil. “Under these circumstances, agromining could be a viable alternative generating better economic returns to local communities,” the authors said.
“Therefore, unlike the competition between food crops and biofuels on fertile soils, agromining does not replace food crop production, but is a temporal activity that may improve soil quality sufficiently to allow food crop production after the metal resource has been extracted.”
The authors recommended that phytomining should focus on species that show the highest levels of hyperaccumulation, noting that in practice only those plants with greater than 1% of nickel in foliar dry matter would likely be of commercial relevance.
They added: “Not all are suitable candidates for phytomining, as the utility of a plant species for phytomining is ultimately determined by the annual harvestable biomass… High biomass yield and material hyperaccumulation are both required to make phytomining a commercially viable proposition.”
In addition, plant species native to the area are more likely to be suitable for agromining than introduced species as they are already adapted to the local climate, pests and diseases; this will also avoid the spreading of invasive species into these habitats.
The authors noted that while the commercial returns from an agromining venture will be limited due to the diminishing concentrations of the target metal in the substrate, the time scale for economic agromining may be considerable; in some cases, it could be sustainable over at least 30−60 years.
However, they cautioned that despite numerous successful experiments, commercial phytomining has not yet become a reality. They advised that to build the case for the minerals industry, a large-scale demonstration is needed to identify operational risks and provide ‘real-life’ evidence for the profitability of agromining.
Tackling mine waste
Global mine wastes represent a potential critical metal resource, and phytomining on degraded or mined land could be used as part of a broader rehabilitation strategy. Hyperaccumulator plants could be a valuable resource in rehabilitation of mine sites or other contaminated areas, which has the dual benefit of extracting metals that are in demand, as well as removing them from the environment where they can be toxic.
In the paper ‘Treasure from trash: Mining critical metals from waste and unconventional sources’ that was published in the journal Science of The Total Environment in March 2021, the authors van der Ent et al noted that to meet the future technological demands of our growing global community, new sources of industry critical metals need to be identified.
Extracting minerals from larger, lower grade deposits across most commodities is required to meet these demands, which in turn generates ever increasing amounts of mining waste.
In addition, the authors noted that some of these materials may contain reactive minerals, including sulphides, which require appropriate management to mitigate against environmental impacts, including the formation of acid and metalliferous drainage (AMD).
One of the paper’s authors, Dr Anita Parbhakar-Fox, spoke to The Intelligent Miner earlier this year about her work on developing new ways to characterise mine waste which is definitely worth a read.
In ‘Treasure from Trash’, van der Ent et al explained that “conventional approaches to managing mine waste focus on breaking source-pathway-receptor pollutant linkage chains at the backend rather than the front”. However, they added that “considering mine waste as a potential critical metal resource provides an opportunity to supplement the demand of critical metals”.
Australian mine wastes from base metals mining (panels A & B) and the metal hyperaccumulator plants Alyssum murale and Berkheya coddii (panels C & D), from the paper ‘Treasure from trash: Mining critical metals from waste and unconventional sources’
The authors noted that in some cases, critical metals were ‘accessory minerals’ to the main target metals at some mines, so they were not recovered during processing as it was not economically or technologically viable at the time. An example of this given in the paper is the Mary Kathleen uranium mine in Queensland, Australia, which closed in 1982 but has rare earth elements in the tailings that could potentially be re-mined.
At other mines, significant amounts of the target metals were not extracted due to dynamic cut-off grades which depended on the metal prices at the time of mining. The paper mentions the Century zinc mine, also in Queensland, that had a mineral resource of 10.2 wt% zinc which was mined. However, the mine tailings contain 3.1 wt% zinc, which is a 77.3Mt resource.
“Exploring mine waste presents an opportunity to conscientiously supplement the demand with the advantage of these materials,” the authors said. “Metal farming is an in situ technique that can be applied to minerals and mining wastes using hyperaccumulator plants to bio-concentrate high levels of metals or metalloids into their shoots and remove them from the substrate, while achieving monetary gain. Indeed, producing critical metals efficiently and sustainably using metal farming techniques to extract nickel, cobalt and thallium appear to be well within reach.
“However, this technology needs industrial research partners to develop appropriately scaled demonstration sites to champion this technology in areas where it is feasible.”
Threat of extinction
There is some urgency to actively engage in hyperaccumulator research. Many hyperaccumulator species are endemic, meaning they are only found in one geographic location. They are vulnerable to threats such as habitat loss which could lead to extinction, and since they grow in areas where the soils are particularly high in certain metals, mining activities can be a major cause of habitat loss.
As Reeves et al (2017) wrote in their letter in New Phytologist: “Timely identification of hyperaccumulator species, along with other metal-tolerant plants, is therefore necessary to preserve them to study their unique physiological mechanisms, and to take advantage of their unique properties.”
Dr Antony van der Ent, senior research fellow at the CMLR who is a named author on many of the papers I referenced in this article, appeared on Gardening Australia in 2019 (see the video below). He said on the programme: “It’s often a race between mining companies wanting to mine a surface outcrop of a metal, and us trying to find these hyperaccumulator plants and try to save some seeds or some plants, that we dig out to keep them basically.”
Dr Antony van der Ent appeared on Gardening Australia in 2019 to talk about hyperaccumulator plants
While hyperaccumulators have several validated applications in the mining industry, they need to be tested on a commercial scale, perhaps via collaboration between researchers and industry partners. Who will be up to the challenge?
My musings on creating value for all through mining recently led me to the team at Amira Global.
Amira was established more than 60 years ago by six large mining companies in order to tackle challenges that were larger than any one organisation could address. The group continues to develop projects at scale which support its members and span a huge range of topics that are helping to address the mega-challenges facing this industry.
Dr Anil Subramanya, general manager for Enabling Futures at Amira, told me about the West African eXploration Initiative (WAXI) and South American eXploration Initiative (SAXI) – two projects coordinated by Amira which are generating huge value, not just for the mining and metals industry but for local communities and research organisations too.
Naturally, I had to find out more…
“When building our geoscience projects, we incorporate pathways for delivering impact,” he explained. “A great example of this is capacity building. What good is research and new knowledge if it is not well understood how to use it?
“Building a community around each project also has benefits and it’s hoped that this will identify other opportunities for work and collaborations. So far, we are on the fourth iteration of WAXI so that seems to ring true! This is central to Amira Global’s Enabling Futures initiative that focuses on delivery and implementation pathways.”
From West Africa to South America
Principal researcher, Professor Mark Jessell from the University of Western Australia (UWA), and Amira Global’s Manager Collaboration, Hayley McGillivray, are leading the projects and agreed to tell me more.
“WAXI is one of the most significant projects in the Amira Geoscience portfolio,” McGillivray said. “It’s based on fundamental research, building a vast geoscience community in West Africa, and working with research, industry and geological surveys. This intersection and collaboration between research, industry and government can be quite a powerful combination and the impact of WAXI over the years speaks to that.”
Professor Mark Jessell, Principal Reseacher at the University of Western Australia (left), and Amira Global’s Manager Collaboration, Hayley McGillivray (right), are leading the WAXI and SAXI projects
WAXI boasts one of the region’s most valuable geographic information system (GIS) and data packages spanning multiple countries and languages, all underpinned by robust geological knowledge and best practice.
As Subramanya mentioned, capacity building is at its heart. This is achieved through in-country industry training courses and the development of masters and PhD students in Africa.
All of these aspects combined lead to a powerful, informative and impactful project.
WAXI is currently in its fourth iteration (nicknamed WAXI4) and is open to sponsorship. The three previous programmes have taken place over the last 15 years.
“One of the benefits of sponsoring WAXI4 is access to the GIS data and research outcomes from the full 15 years of project work,” McGillivray told me. “We would like to start a conversation about the benefits for those companies actively exploring, mining or interested in the West African region.”
WAXI4 builds on the existing collaborations and research strengths to include new potential for mineralisation in the Archean sedimentary basins and the Pan-African orogen, which in turn increases the project’s geographic scope.
Jessell explained: “The primary focus of WAXI4 remains the Birimian formations, and a series of modules on mineral systems will be undertaken to tie together the different geographic and age domains. Of course, we retain our commitment to capacity building by working with the recently launched NGO, Agate Project Ltd, which supports capacity building in the earth and planetary sciences across Africa.”
He added: “In terms of future work, we are at the early stages of understanding what a comparison project to look at the geological relationship between WAXI and SAXI looks like.
Leaving a positive legacy
To date, WAXI has produced over 95 Masters and PhD students, of which two thirds come from Africa. This will help ensure the research continues long after the project finishes. Some of the students trained through the project have gone on to lead further research or take industry roles and are leading field programs in the region.
“Graduates of WAXI are already working as lecturers in five West African universities, ensuring the knowledge they have gained in partnership with WAXI can be passed on to the next generation,” said Jessell.
Another legacy of the WAXI initiative is the project structure with the cross-country regional datasets and compilation, fundamental research to develop understanding and local research and industry capacity building.
This has since been successfully replicated in the SAXI project and the team are currently looking for the next destination where the mining industry would like to see a similar project.
“Early-stage collaborations offer multiple opportunities, including increased knowledge and understanding, a more regional context to project knowledge, and the identification of new targets,” said McGillivray.
“Mining is changing, and the more information and understanding companies have around their primary asset (the orebody), the more informed their choices will be as the project progresses. Equally, a robust understanding of orebody formation and mineral systems may help in further discovery.”
To date, WAXI has produced over 95 Masters and PhD students (Image: Amira Global)
At a more practical level, multi-sponsor collaborative projects can offer leveraged funding opportunities and access to data and insight and knowledge that would not otherwise be available.
Where to next?
“Do you think more mineral exploration projects should look to incorporate shared value initiatives going forward?” I asked the team.
“Amira would love to see collaborative R&D projects become a more commonly used tool and part of every organisation’s exploration strategy,” McGillivray said.
“Knowledge is power, and there is high demand for expediting new discoveries and progression of exploration projects. The WAXI model has already led to a sister-project, SAXI, which was proposed by the industry itself to address similar challenges in the Guiana Shield. We are currently seeking to understand what other regions, such as East Africa, may benefit from a project of this nature.”
Subramanya added: “Amira provides an independent, non-partisan and trusted global platform that can be used to harness the true power of collaboration, leading to innovation and implementation of new ideas and technology.”
WAXI fast facts • Operating in 12 countries • 75 partners involved over 15 years • 95 Postdoc, PhD, Masters and honours projects, 2/3 of them African • 109 international publications • 650GB exploration geoscience database • 1,800 person-days of technical training in West Africa • 650,000km2 of geophysically constrained geological mapping
As 2021 draws to a close, and we all begin winding down and thinking about setting our out-of-office responses for the break, it’s a good time to reflect on what has happened over the last year.
While there are some exciting changes in the works for The Intelligent Miner in 2022, first let’s revisit some of the top articles we published in 2021…
(If you want a refresher of what happened in 2020, check out last year’s post on the top 10 most read articles of 2020)
Carly Leonida interviewed Dr Anita Parbhakar-Fox from the Sustainable Minerals Institute (SMI) at The University of Queensland, who is developing new ways to characterise mine waste to better understand their potential value.
1. Interview with the alchemist
Ailbhe Goodbody explored how urban mining can add significant value to traditional mining business models, and spoke to Argo Natural Resources Fred White about the company’s work with Deep Eutectic Solvents.
2. Urban mining: the hidden value of e-waste
3. How to deliver mining projects on time and in budget
Carly Leonida and Jason Fearnow explored how a more holistic approach inclusive of new models and optimised teams can deliver better outcomes for large-scale mining capital projects. Read on…
The second part of Elizabeth Freele and Carly Leonida’s two-part discussion on society’s relationship with the mining industry and the ways in which it is changing.
4. Consumerism & the mining industry: part 2
Carly Leonida spoke to Sonia Van Ballaert from IBM Global Markets and Mark Hannan from Shell about how decarbonisation in mining is not purely a challenge, it’s also a great opportunity for operational optimisation.
5. Decarbonising mining: shifting from a challenge to opportunity mindset
Carly Leonida shared her wish list of 10 things she would like to see happen in the mining sector over the next decade, in no particular order.
6. My 10-year manifesto for the mining & metals industry
Carly Leonida spoke to Novamera CEO Dustin Angelo to find out how precision mining could solve some of the mining industry’s biggest challenges.
7. Sustainable mining by drilling
Ailbhe Goodbody reviewed some key areas where 3D printing is proving useful, from printing spare parts and PPE to producing industrial-grade diamonds for cutting.
8. Five applications for 3D printing in mining
9. Good as new: mines see cost & energy savings from remanufacturing
Ailbhe Goodbody examined how remanufacturing is a smart move to consider for mines that are looking to drive down their waste and improve circularity in their businesses while reducing operational costs. Read on…
10. Graphene: mining’s wonder material?
Ailbhe Goodbody looked at some of graphene’s potential applications in the mining industry and speaks to Puruvi Poddar from Tirupati Graphite and Mike Bell at First Graphene to find out more about their R&D in this area. Read on…
It’s interesting to see how the conversation around water in mining has evolved in recent years.
When I started out as a mining journalist 15 years ago, I was often tasked with writing features based around pumps and pipes, mine dewatering, sometimes water treatment or desalination…
The solutions covered were interesting, but what struck me was the way in which water was regarded. There was either too much or too little of it.
Although integral to the mining process, the industry seemed to (some companies still do today) see the presence of water on site and the challenges it brought as a bit of a nuisance. Just another risk to be mitigated.
It’s only been in the past five years that I’ve been asked to write articles that consider water in a more positive and holistic way – as a tool to create social change, to generate green electricity, to re-wild the landscape post extraction.
Waterless mines are a fantastic ambition, and something that I hope to see before 2050. The benefits that dry comminution, separation, beneficiation etc. could bring to the table in water starved areas are undeniable.
However, I would argue that not all mines could or should be waterless in the future. (Closed-loop processes and operations are another matter. One that just makes good sense.)
If we look beyond risk, the opportunities that water offers mining companies to partner with indigenous peoples for social growth are significant. Likewise, where poor water quality exists, mining companies have the chance to leave local environments in a better state than when they found them through proper treatment.
It may require a little digging (excuse the pun) and a healthy dose of imagination but, if we care to look, there will be many positive opportunities, however small.
Identifying them will elevate the status and value of water which, in turn, will inspire more responsible management practices and boost returns. The process is cyclical, and it will balance out the associated risk creating a net positive effect.
Wherever your company is in its journey with water, here are five excellent articles/reports to further your research.
- Canadian Mining Journal, January 2022 How holistic water management supports mining’s ESG goals David Kratochvil of BQE Water examines how holistic water management practices across the mine lifecycle can help miners towards their sustainability, inclusivity and social acceptability goals. He explains it much more eloquently than I did above
- Stantec, January 2022 Native American communities receive renewable drinking water technology through Resolution Copper and Stantec A brilliant example of how mine water management and innovation deployments can generate shared value. Also, a mind blowing technology in action!
- WaterOnline.com, January 2021 Building trust with stakeholders through transparency and consistency in water quality reporting Alice Evans looks at how water quality control can help address the trust deficit in mining
- ICMM, August 2021 Water reporting, good practice guide Because you can’t manage what you can’t measure. The latest version of ICMM’s water reporting guide is a cornerstone of good mine water management. Whether a member or not, all companies can aspire to best practice
- North American Mining, June 2021 Toward a waterless mine Jonathan Rowland looks at how waterless processes can help to address risk and increase the sustainability of businesses in the mining space. Lots of practical examples here
It’s widely accepted that the green energy transition is wholly dependent upon metals that the mining industry produces, and that circularity will be key in negating the effects of both extraction and consumption on the planet.
The concept of circular economy is founded upon interconnectedness. However, to create feedback loops and ensure the continual flow of value in metals production requires a significant shift in mindset.
Mining is an industry that has, for some time, been reliant on linear pathways for products and services. It’s also one that considers itself to be different to the rest… Set apart by its ‘unparalleled complexity’.
Achieving circularity will require us to consider the industry as just one part of an ecosystem, or a cog in a much larger machine. Treat them as separate and, in time, the cog will fail to fit and turn in the way that it should. And this particular machine is dynamic; ill-fitting cogs can be made obsolete.
I recently attended an excellent presentation that gave some much needed perspective on this topic. Professor Richard Herrington of London’s Natural History Museum delivered the inaugural MinSouth lecture of 2022 virtually on January 13. The topic of ‘Mining our way towards a green future’ was perfect given the backdrop of COP26 and also the fact that I was writing this article.
Herrington is an economic geologist and has advised the UK government in developing its net-zero strategy. He explained that mining is absolutely fundamental in achieving the main goals of COP26, particularly in securing a global net-zero future by mid-century with a 1.5oC maximum temperature rise, and in adapting to protect communities and habitats.
More minerals, more problems?
COP26 and its proceedings highlighted, not only the urgency of the green energy transition but also the mineral intensity.
According to the International Energy Agency’s (IEA) 2021 report on The Role of Critical Minerals in Clean Energy Transitions, the mineral requirements of an energy system powered by clean energy technologies differ widely to one run on fossil fuels. For example, a typical electric car requires six times the mineral inputs of a conventional car, and an offshore wind plant requires 13 times more mineral resources than a similarly sized gas-fired power plant.
Herrington explained that to meet future projections for both critical metals and bulk commodities demand which is, in certain cases, phenomenal – graphite, lithium and cobalt, could increase by nearly 500% by 2050 according to the World Bank – requires an integrated approach.
A wind plant requires 13 times more mineral resources than a similarly sized gas-fired power plant. Image: Unsplash
This includes a steady pipeline of greenfield mining projects; Herrington said that lead times for new mines today vary from 12.5 years up to 20 years for most commodities, and collaboration with communities and governments will be key to expediting this process.
A little closer to home, the reinvigoration of historic mining districts like Cornwall in the UK, and Kiruna in Sweden, offer significant potential for sourcing minerals like lithium. Most of these have mature supporting industries which could also benefit. The exploration of brownfield prospects (extensions to currently mined orebodies and satellite deposits) will be another contributor, and some newer, less conventional prospects (deep sea mining, anyone?) could also be key.
In addition to new sources of metals, more efficient extraction processes for current mining operations will also play a role (more on this later), along with better recycling systems for metals that are currently in circulation.
Why recycling isn’t enough
Many environmentalists will argue that recycling is the answer to future metals shortages. While it will have a role to play, even if we could recycle 100% of current supply, which is impossible today, increased demand means that need would still outstrip supply in the future.
Herrington used the example of titanium to illustrate this: around 90% of titanium in circulation today is recycled. However, this only satisfies about 50% of current demand. Another factor is the time lag between manufacturing and a product reaching its end of life; the electric vehicles produced today probably won’t begin to be recycled until 2030.
Very little lithium, graphite or cobalt (all important components in electric batteries) is recycled today. However, the IEA states that by 2040, the recycling and reuse of batteries from electric cars and storage systems could reduce the primary supply requirement for some minerals by up to 12%.
In short, recycling does have a role to play in a low-carbon, circular future. However, to keep global temperature rises to a minimum, more metals and mining are necessary. It’s therefore important that this mining is ‘done right’.
Cradle-to-cradle mining
Herrington closed his presentation by explaining that the cradle-to-cradle concept developed by William McDonough and Michael Braungart will be critical in reducing the negative impacts of future of mining operations, and in the industry maintaining its social license to operate.
Once society does decide to mine, we need to do it in a way that considers the entire mine lifecycle and creates a net positive effect for both people and the environment.
Both the current mine lifecycle and the way in which mining businesses are structured are quite segmented which makes this ambition hard to achieve. However, Herrington argued that revolutionising workflows and structures will make it easier to protect and reconstruct ecosystems, and incorporating inherent regeneration will mean that when extraction ends, the landscape is ready for the next lease holder.
Environmental and social governance (ESG) done right could also drive other benefits such as the creation of local supply chains and the restoration of biodiversity.
Of course, redesigning mining processes and protocols is much easier at greenfield operations which typically have fewer physical and financial constraints. Brownfield projects tend to be committed to certain footprints and technologies.
Although it’s far from impossible, I’ve read very little about the practical steps and strategies that mines (both new and existing) can take to incorporate circular principles into their operations.
I was therefore delighted to read the paper Circular economy for mining operations: key concepts, drivers and opportunities, written by Alan Young and Laura Barreto of MERG and Karen Chovan of Enviro Integration Strategies, and published in December by Natural Resources Canada.
The paper highlights the myriad ways in which mines can participate in and practice circular economy, from on site to beyond via partnerships, as well as through materials, equipment, infrastructure and land use. Again, the cradle-to-cradle concept is central to these efforts.
Chovan, who spoke to me in 2020 about opportunities for greater circularity in mining, joined me to discuss the paper in early January.
“It addresses an initiative under the Canadian Mining and Metals Plan (CMMP),” she told me. “To optimise circularity in mining requires us to think beyond the footprint of individual sites, and to partner with neighbouring and/or different commodity producers (co-opetition?) and other companies within the supply network, including buyers and end-users. The paper gives lots of practical examples on how that can be done.
“Every site, every commodity and region is unique. There is no single blueprint for how a fully circular mine should look, so we’ve explored all of the possibilities and how they can be pieced together to create a solution that works for each mine site.”
Recycling does have a role to play in a low-carbon, circular future. However, to keep global temperature rises to a minimum, more metals and mining are necessary. Image: Unsplash
Sustainable is circular (and vice versa)
Circularity doesn’t replace sustainable development; the two go hand in hand.
The report explains: “Circular economy complements and builds on ‘responsible mining’ programs by bringing disparate initiatives under an integrated strategy. By solving for mine waste, water risks, energy use and carbon emissions, disturbed and impacted lands, and social impact concerns through a systems-based integrated strategy, circular economy contributes to responsible mining.”
In essence, circular economy strategies focus on transformative approaches that design waste and pollution out of products and services, while capturing greater economic value throughout supply networks by rethinking the linear business models we see today.
For mines looking to incorporate circular principles into their operations, some key areas outlined in the paper include:
- Stock optimisation – extending the value of materials;
- Eco-effectiveness – going beyond eco-efficiency;
- Eliminating the concept of waste by extending resource value;
- Extended producer responsibility;
- Circular product and process design; and,
- Creation of social value for everyone.
“Circular practices introduce mechanisms to reduce water and energy consumption and CO2 emissions, and to eliminate the generation of waste,” state the authors. “These lead to reductions in costs related to operational risk management and consumption in general.”
The report suggests that, where natural resources must be used, mines should consider low impact options. For example, using mine-impacted waters from the site in place of fresh water, or replacing fossil fuel-based power systems with renewable energy and hybrid electric options.
Extracting embedded value from mining wastes to make the most out of stored geological resources, extending materials life and industrial symbiosis i.e. creating value through waste exchanges with others, could also be helpful. In mine reclamation, shifting the focus from harm reduction to value generation could involve regenerating land for recreational, commercial, agricultural purposes and restoring natural ecological systems.
Of course, better management of natural resources is just one way in which mines can benefit from circular principles. To derive the maximum value from these initiatives, a comprehensive approach to circularity is required across businesses and across the mine lifecycle.
And so, this article has (pardon the pun) come full circle.
As with so many initiatives, the key in making mining practices more circular will lie in steady progress. Each and every change, however small, will start to add up in time.
The most important thing is to commit to making change happen and to bear in mind the ecosystem approach that we discussed earlier.
Keep the bigger picture in mind.
Reading list…
I don’t usually finish articles with a reading list (we save that for the newsletter!) However, on this occasion, I found a treasure trove of online resources that I felt would be helpful to share.
- “Mining our green future” May 2021, Richard Herrington
- “Mining and metals and the circular economy” 2016, ICMM
- Building the circular economy web page, 2022 Smart Prosperity Institute
- “Mining for circularity: five strategic insights” 2021, World Circular Economy Forum
- Circular Economy Solutions Series: Mining & Metals web page, 2021, Circular Economy Leadership Canada
- “The role of critical minerals in clean energy transitions“, May 2021, International Energy Agency
