Critical minerals: should the UK reopen old mines?

BY JON EVANS | iMAGE: SHUTTERSTOCK 

China dominates the world in the production and processing of critical minerals. But growing demand means the UK now needs urgently to look at our own reserves – starting with reopening old mines.

At the end of 2023, the UK House of Commons Foreign Affairs Committee became the latest official body to wade into the issue of critical minerals. It did so by publishing a report, A rock and a hard place: building critical mineral resilience, based on a year-long inquiry into the security of UK access to critical minerals. The findings were not comforting.

‘For three decades we have been asleep at the wheel, repeatedly failing to recognise the importance of critical minerals and the dangers of our current reliance on autocratic countries,’ said Alicia Kearns MP, chair of the Foreign Affairs Committee, at the launch of the report.

The report highlights growing global concern about security of supply. According to the International Energy Agency (IEA), countries around the world have so far introduced over 200 policies and regulations regarding critical minerals, with half appearing in the past few years.

‘The new normal might become one of increasing tensions and competition over access to critical minerals and that requires quite a lot of careful consideration,’ says Kathryn Moore, senior lecturer in critical and green technology metals at Exeter University, UK.

Critical minerals are elements and materials essential to the functioning of our modern world, possessing special physical and chemical properties used in multiple cutting-edge technologies, especially green and electronic technologies. They include lithium, cobalt, nickel and graphite, used in rechargeable batteries; rare-earth elements such as neodymium and dysprosium, used in solar cells and to produce the powerful magnets in wind turbines and electric motors; and silicon, gallium and indium used in electronic devices.

In many cases, the properties of critical minerals are highly specialist, such as conducting electricity at specific temperatures or retaining permanent magnetism. ‘They have a low substitution potential,’ explains Moore, meaning they are sometimes the only ones that will do the job. Some critical minerals are solely produced as byproducts from the large-scale mining of other non-critical elements, as they can occur in the same ores. None are mined in the same quantities as iron, copper and lead etc. Nevertheless, geologically speaking, they are not exactly rare.

The problem is that, currently, their production is concentrated in just a handful of countries, sometimes just one, making future supply disruption a distinct possibility. Especially as demand for green technologies reliant on critical minerals is forecast to grow substantially over the next few years, driven by countries’ efforts to reduce emissions of greenhouse gases. The IEA predicts that growing demand for rechargeable batteries, in electric vehicles and energy storage, and for solar cells and wind turbines could increase demand for critical minerals by three and half times by 2030, to 30m t/year.

Chinese influence

Demand for many critical minerals could thus soon begin to outstrip supply. At the very least, this will raise prices, which is already happening, but at worst it could lead to a handful of producing counties having a stranglehold over the entire global technology sector. The biggest concern is China, which not only dominates the supply of many critical minerals, including gallium, silicon and the rare-earth elements (see Table), but has shown a readiness to use them as an economic and political weapon.

In 2010, in response to a dispute over the East China Sea, China temporarily stopped exporting rare-earth elements to Japan. Since then, the relationship between China and many Western countries has only become worse. In 2023, as a first shot across the bows, China imposed export restrictions on gallium and germanium.

Even for other critical minerals, China often dominates processing, where the coarse mined ore is transformed into refined metal. For example, Australia may be the leading producer of lithium and the Democratic Republic of the Congo the leading producer of cobalt, but China is the leading processor of both. This is the result of a deliberate strategy adopted by China in the early 2000s to take advantage of its geological reserves of critical minerals to dominate production and processing.

‘One of the things China has done really well is that it’s vertically integrated its supply chain,’ says Moore. ‘It didn’t just undercut global mining in terms of the unit cost of production of metals, it also worked to move further downstream in the supply chain and to retain a lot of the processing in component manufacturing.’

Other countries with geological reserves of critical minerals are following China’s lead. ‘The further downstream you go in the supply chain, the more lucrative the business becomes,’ Moore explains. ‘If a country really wants to use raw materials production as a route to sustainable development, it really needs to vertically integrate.’

For example, Indonesia, which is a leading producer of nickel, now also dominates nickel processing and has introduced measures to ban the export of unprocessed nickel ore. Many producing countries also want to use their critical mineral reserves to help build up their own technology industries, potentially limiting the amount available for export. Thus, the race is on to secure supplies of critical minerals, and it is a race in which each country is against every other country, hence the proliferation of policies and regulations. As the Foreign Affairs Committee points out, the UK has come rather late to this party. Whereas both the US and the EU have published criticality assessments for minerals since 2008, the UK government only published its Critical Minerals Strategy in 2022. Before Brexit, however, the UK did take part in the EU’s assessments.

The UK’s Critical Minerals Strategy identifies 18 critical minerals (see Table), but this includes a single entry for rare-earth elements, which comprise 17 elements. Thus, in total, there are 34 minerals the UK considers to be critical for its economy. Different countries tend to draw up slightly different lists, but there is a great deal of overlap.

One way countries are trying to secure supplies is by establishing trade agreements with one another. Perhaps the most ambitious effort to date was set up by the US in June 2022, in the form of the Minerals Security Partnership. This is a critical minerals alliance where partner countries pledge to cooperate in strengthening global critical minerals supply chains. The partnership has already attracted many of the US’s usual allies, including the UK, but not China, which shows the limitations of any such efforts.

As long as China is the leading producer of 11 of the 18 critical minerals identified by the UK, including the 17 rare-earth elements, and the leading processor of others, trade deals and partnerships with ‘friendly’ countries will only accomplish so much. And if the supply of certain critical minerals does become restricted, even friendly countries are going to favour their own technology industries.

Table: Critical minerals identified in the UK Critical Minerals Strategy and the leading producer

* These are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium. Of these, neodymium, praseodymium, dysprosium, and terbium are in particularly high demand.

Complex geology

Many countries are understandably looking at the potential to boost domestic production. Often, as with the UK, this is essentially being done from a standing start, by first determining exactly what reserves of critical minerals they possess. Here, the UK has both advantages and disadvantages. On the one hand, the UK is a comparatively small country. ‘We have to acknowledge that ours being a small landmass with quite complex geology, we don’t have ore deposits on truly vast scales,’ says Moore.

On the other hand, this complex geology means the UK could have small reserves of quite a few critical minerals. ‘While we might not have a huge world-class ore deposit of every kind, there’s a little bit of most things here,’ Moore adds.

What is more, the geology of the UK is well mapped, while thousands of years of mining have helped to reveal what is under the ground. In 2023, the UK Critical Minerals Intelligence Centre (CMIC), part of the British Geological Survey, used this information, together with maps of soil chemistry and stream sediment, to identify places in the UK likely to possess reserves.

Known as a ‘mineral systems’ approach, this is based on the idea that geological processes that produce critical mineral ores from specific types of rocks are fairly well known. For example, graphite forms where carbon-rich sedimentary rocks have been metamorphosed, while rare-earth elements are usually found in carbon-rich carbonatite rocks and alkaline igneous rocks. A few critical minerals, such as tin and tungsten, have long been mined in the UK, while others are often found in association with non-critical minerals mined here, such as copper, gold and zinc.

The CMIC calculated that the UK likely possesses reserves of all but one (niobium) of the 18 minerals identified in the Critical Minerals Strategy. These reserves are concentrated mainly in the Scottish midlands, the Lake District, northwest Wales, mid-County Tyrone in Northern Ireland, and Cornwall and Devon. Work is already under way to determine whether any of this potential can be realised. Unsurprisingly, much of this work involves existing mines, many of which had been abandoned and are now being restarted.

For example, a company called Cornish Metals is working on restarting the tin mine at South Crofty, as well as mines at other sites in Cornwall. ‘South Crofty, which was the last tin mine to close, is dewatering now, the ground is being prepared and it’s ready to go,’ says Moore.

Cornish Metals have signed a deal with another company, Cornish Lithium, to investigate the potential of extracting lithium and other critical minerals from both rocks and geothermal waters at South Crofty and several other sites. In addition, a company called Tungsten West is looking to restart the tungsten and tin mine at Hemerdon in Devon, which it claims is the second largest tungsten resource in the world.

All these mines originally closed because they could no longer compete with mines in other countries, particularly China, which is now the leading producer of tungsten and tin. But as the demand for these minerals increases, along with their prices, these old mines are becoming viable again, assisted by new, more efficient mining technologies.

What is more, the waste from these old mines, as well as from old coal mines, could become another valuable source of many critical minerals, which weren’t of interest when the mines were originally operating and so weren’t extracted. After hundreds of years of large-scale mining, there is a lot of waste. An estimated 223bn t of tailings - the material left over after ore has been processed - were generated globally between 1771 and 2019, with perhaps 10 times as much waste rock.

While increasing demand for critical minerals threatens supply disruptions, the associated price rises could help to prevent such disruption, by allowing a whole host of previously uneconomic reserves to become viable. ‘Europe has a lot of ore deposits that are sub-economic,’ Moore explains. ‘But in the event of a crisis, the commodity price would skyrocket and suddenly if you can switch on mining quite quickly and responsibly, you would be able to capitalise on that high commodity price and then a higher unit cost of production wouldn’t be as negative an issue.’

So how to switch on mining ‘quickly and responsibly’? Moore has been working on an approach known as small-scale mining, designed for the short-duration exploitation of small-scale, high-grade deposits. ‘We’ve learned a lot about the timings that it takes to design, build, and deploy in a licenced and managed way,’ she says.

Crucially, however, the systems and processes for this small-scale mining need to be put in place now, all set to go when a supply crisis for critical minerals hits in the future. ‘That’s where, maybe in five to 10 years, the research we’re doing now is going to be crucially important,’ Moore says. ‘But we need to be ready.’