HIDDEN IN THE hills of St Dennis in Cornwall, a short drive away from the mining village once known as the richest square mile in the world, lies a gigantic hole in the ground. This is not unusual; the area is pitted with hundreds of old and abandoned mines where for almost 300 years tonnes of copper, tin, tungsten and clay were taken from the earth. What is odd, at least in 2021, is the noise coming from it: the steady sound of digging.
Finding the source of the sound involves a cautious ascent on a rocky path to the mouth of the Trelavour Downs, where dense vegetation gives way to a stark landscape ripped apart by heavy machinery. Entire chunks of land are missing, leaving behind white craters where hills abruptly turn into chasms. On a bright day, looking at the white walls is like gazing into the Sun.
In the midst of this scene on a Tuesday afternoon in April is an almost comically small red digger, chugging noisily away at a small hole in the ground. This, say hard hat-wearing geologists from lithium-extraction company Cornish Lithium, is the place that will herald a mining renaissance.
Cornish Lithium is one of two local companies – the other being British Lithium – that believe that this shiny metal could be a new gold rush for Cornwall; an opportunity to revive an industry that waned decades ago and left many of the traditional mining villages impoverished. But their mission is bigger than that: they think these deposits could unlock the UK’s electric dreams, making the extraction of lithium and manufacturing of lithium-ion batteries possible in the country for the first time, reducing the substantial ecological footprint of current battery technology. They believe there could be enough lithium in Cornwall to meet UK demand when the country moves from fossil fuel vehicles to electric ones – they just have to find a cost-effective way to get it.
IT'S THANKS TO the Cornish miners of the past that today’s companies know where to dig in the first place. To identify a potential site, Cornish Lithium geologist Adam Matthews painstakingly poured over aged maps drawn by hand, with scratchy letters showing the depth of each of the dig sites and what the miners found. Each borehole extends underground first vertically, then off in shoots, like the roots of a tree. While there are a lot of historical geological maps out there, he often found them in rather peculiar places. One treasure trove was in private hands, in the attic of an historic mining-enthusiast who had amassed a cache of them with a friend over the past 100 years.
The cost of digging blind would be prohibitive for a startup. To narrow their search, Cornish Lithium used machine learning to find patterns in the historical mining data, hoping to find lithium on the first try. They layered all of the maps on top of each other to create one master map, and worked to fill in the gaps in their knowledge – an endeavour that Matthews says took a year and a half.
“You might notice that the measurements are different here,” he says, pointing at one of the boreholes drawn on the maps in Cornish Lithium’s office in Truro, a few kilometres from the coastal town of Falmouth. “On these maps everything’s in fathoms [one fathom is 1.8 metres]. In some cases, but not all cases, they measure the distance of it inclined – whereas now you measure vertically. Depending on the year, they might have done one or the other.” He smiles: “You have to do trigonometry to figure it out.”
Sometimes, the map writers will try to tell you how deep a hole is, but won’t tell you where they started measuring from. He points to numbers scratched in ink on another map – “can you see here, 70 to 112?” The number 70, he explains, is what’s called the fathom level. “But it’s not the distance below the surface, it’s the distance below the ‘level’. But there is no standard measure for where the level is,” he says. “Think of it as the drainage in your house: it’s in a certain place, and it’s slightly inclined to allow it to drain… but it’s a very different place if it’s on a hill, or in a valley.” Underground, this means that the hole marked as 112 fathoms deep could end at a very different depth than what the map appears to suggest.
In some cases, past miners didn’t make records of where they decided to dig at all. There were huge black spots of information missing on mines that Cornish Lithium could unknowingly crash into, destabilising its plans, which Matthews says he only managed to shed light on thanks to consulting a former miner called Terry Cotton who had worked in the area for 40 years. Some of the mines marked on the map are comically shallow. “That’s probably people just having a go,” he says. Other people tried to reproduce maps and inserted errors “as they put their own spin on it”.
On his computer at Cornish Lithium’s office, Matthews points to what the maps ultimately helped him build: an X-ray-style 3D model of the entire landscape, colour-coded to show the angle and age of each of the shafts dug to extract the clay. It looks like hundreds of different coloured straws, stuck at different angles into the ground: his roadmap for where to dig.
Where there were no maps available, he also had help from eyes in the sky. Alistair Salisbury, an exploration geologist for Cornish Lithium, has been mapping the terrain that even drones can’t reach. His piece of the puzzle involves taking pictures of fault lines that extend to the coast, and importing them into the software. On his screen, drone imagery of the coast shows huge gaps in the granite, which he follows inland, drawing onto the 3D model. The structures that are visible by drones at the coast are formed by the same chunks of rock found 600 to 700 metres down inland. “We can use any interpretations that we make on the coast to infer further inland, so that’s what the fracture zone might look like, that’s what permeability might be,” he says.
Salisbury’s job is to explore any possible avenue to quickly access lithium, however unlikely. At one point he worked on testing all of the natural springs across Cornwall, which were once associated with druids and holy water, for potential lithium in the groundwater. “We had a map of all the holy wells, so we went and tested some of them to see if they had elevated lithium levels, or if they could tell us more about what’s happening,” he says. His team traipsed around the land trying to find these water sources, in a pilgrimage that ended up being mostly futile. “We did well after well. Some of them were just concreted over, and there was just a little shrine there.”
Salisbury has also mapped the entire north coast, capturing spectral information – data from across the electromagnetic spectrum – to look for alternation signatures of key minerals associated with geothermal activity. “What we see with our eyes is a very small portion of the electromagnetic spectrum,” he explains, bringing up another 3D geological map on his computer. “What we use is speed cameras, which soak up all the information in the electromagnetic spectrum, which is about 15 magnitudes more information than what you can see with your eyes.” He gives the metals in the ground false colours, like pink, yellow or orange, to show where they are concentrating on the ground. He clicks on his screen and graphs with dozens of different coloured waves appear, like a heartbeat on an ECG monitor.
“We can use that to understand which of these structures have seen more alteration and more fluid flowing through them,” he says. “So we can say that these structures might be more prospective for lithium or geothermal waters further inland.” The light bouncing off the ground has produced what he describes as “fingerprints in the ground”. Mostly it’s kaolinite that he’s looking for, the white mineral that is a tell-tale sign that there is clay in the ground and is associated with the hydrothermal activity of geothermal waters – and lithium.
He hopes the fingerprints he collects will include the entirety of the South West in the future, thanks to a project with the UK Space Agency which aims to expand his reach with satellite imagery. This data may seem excessive, but for modern day mining, it is half the battle. Next, the data needs to be tried and tested before companies can be granted permission to extract at scale. To do this, they need to dig.
TO EXTRACT LITHIUM from Trelavour Downs, the four-strong Cornish Lithium mining team is making a hole every few metres using a drill rig, with almost 1,500 metres of diamond and 2,500 metres of ‘reverse circulation’ drilling planned. The rig pushes deep into the ground and inserts gallons of pressurised water to lubricate it and extract drill cores from the granite. The cores, perfectly-shaped stone cylinders about a metre long and roughly the diameter of a table-tennis ball, are passed to members of the team to tag, examine and crush to release the lithium contained within. This takes a lot of energy: around five per cent of the electricity generated globally is spent crushing rocks in lithium mining.
The team uses technology licenced from Australian company Lepidico to process the samples on site, without the need for further refining. Cornish Lithium says it is progressing towards bulk metallurgical testing to handle many samples of lithium at once and plans to construct a pilot test plant to ramp up processing.
“We need to mine the rock quarry, and then crush it,” summarises Lucy Crane, senior geologist, business development at Cornish Lithium. The process of extracting the lithium involves separating out the lithium micas – groups of minerals found in granite that look like tiny shiny sheets – and then processing them in a hydrometallurgical plant, which can produce quality lithium hydroxide, the substance used in electric batteries. Cornish Lithium uses water to do this instead of roasting at high temperatures, as this uses less energy and produces no emissions. The plant will be the size and shape of an average Tesco Metro.
But hard rock is not the only place where lithium can be found. Naturally-occurring underground hot springs in Cornwall are enriched with geothermal fluids called brines, which contain minerals leached out of the granite in the Earth’s crust. Alongside hard rock extraction, Cornish Lithium plans to use direct lithium extraction in the brines, which will allow it to selectively extract the lithium by putting the liquid through a series of filters. Ultimately, the company aims to produce a battery-quality lithium hydroxide product from the geothermal waters.
Crane says that Cornish Lithium is trying to move away from labelling what it is doing as mining: “We’ve started calling it mineral extraction rather than mining, because mining kind of conjures up those images, doesn't it, of people going underground and getting dirty, and Poldark.” Whatever the company labels it, it’s not the only player looking to exploit the riches hidden in these Cornish hills. British Lithium is also in the exploration stage of its venture, engaged in a race to prove that the much-acclaimed deposits of lithium are where it says they are, and that it has the right technique to extract them.
British Lithium plans to focus entirely on hard-rock extraction, drilling diagonally in ten to 15 areas near St Austell, southeast of St Dennis, in an exploratory drilling campaign. Similarly to Cornish Lithium, its first port of call was to rely on geological maps. When it found a potential lithium source, it got permission from landowners to scope out possible dig sites. It then sent an exploratory team of geologists on site to scan rocks with enough energy to analyse the atoms in the inner shell. “You point an XRF gun [a portable tool designed to perform elemental analysis on materials] at it and it will tell you what it’s made of. So our geologists wandered around picking up rocks, shooting this gun at it, and it tells you what it’s made from,” John Walker, British Lithium’s strategic adviser, explains. “Once we actually identify surface samples, true geology starts. We have to do a surface map, we take the rocks back to the laboratory, we do a more sophisticated analysis of what the material is made from.”
The team hopes to open a conventional open-pit mine in St Austell in 2023. Unlike Cornish Lithium, British Lithium is betting that hard rock alone will provide enough lithium to build a viable mining operation. A £2.5 million grant from the government allowed them to start construction on a pilot processing plant in 2021. “We’re in a brownfield site, it’s already disturbed. We can restore the site from the previous mining of china clay,” Walker says. “I always joke that we’re actually just moving a hole, we’re not creating a big new one. You’re mining two million tonnes of rock to make 20,000 tonnes of lithium carbonate. The majority of what you take out of the ground, you’re going to be putting back.” According to the company’s feasibility study, it has to produce 20,000 tonnes of this material for 20 years in order to be granted permission to operate, which means it needs to prove there is a minimum of 400,000 tonnes of lithium carbonate to make it worthwhile digging. At that rate, it would be possible to power over 500,000 electric vehicles a year.
Walker says the company is trying to act as sustainably as possible. Rather than using a diesel mobile plant to power the dig site, it will use a hydrogen or lithium-ion battery powered mobile plant. Rather than dump trucks, it will use electrically-powered conveyors. “We want to bring a strong net benefit to the world and not add to its challenges,” he says. He predicts that the project will need 20MW to operate – meaning that if mining operations from British Lithium and Cornish were running at the same time, they would overload the grid. This is an obstacle that Walker hopes will be solved by the construction of an off-shore wind farm on the coast of Cornwall. “It kind of isn't there now,” he concedes. “But it should be, it will be, by the time we're ready to go.”
He has high expectations. “We will probably be putting more than £100 million a year into the local economy, and some 8,000 jobs,” he says. He predicts that the dig site will be up and running within three to five years, and together with Cornish Lithium, he expects that there will be close to £1bn of investment – “back to the St Austell heyday of the 1980s”.
TRYING TO EXTRACT lithium from brine involves far more risk. It is hard to predict whether there is enough concentration of the mineral in the hot, concentrated saline solution to make mining it worthwhile, and how to accurately extract it. The mining process is like taking a kilometers-long straw, punching it through the earth’s crust and sucking out the water contained within, hoping that it will be enriched. In arid locations around the world such as South America or Australia, the water is pumped up to the surface into a series of ponds and left there for months to evaporate into a lithium-concentrated liquid. This is then taken to a recovery plant which filters the remaining water for boron or magnesium, and is treated with sodium carbonate to create lithium carbonate, which is filtered and dried. Cornish Lithium plans to filter the water directly from the source, saving time and avoiding the environmental impact of evaporation pools, which would not be viable in British weather.
This is why, last winter, Matthews found himself in a small, leaky shipping container on the edge of a forest in Redruth, waiting for two months to see whether his calculations and mapping had paid off. His team had drilled two exploration boreholes in shallower geothermal waters, at a depth of around 1km each, where the water is between 70 to 80 degrees Celsius. There was already a drill rig there, which they had to avoid hitting.
“At night it would freeze, obviously. And then if it was sunny during the day, it would rain inside the shipping container, because all the ice would melt on the ceiling,” he says. He locked himself into this strange microcosm for six days a week, watching the drill go down by around 25 to 30 metres every day. During that time, he would spend time updating his calculations in real time. “It was making sure that we were not hitting the structure, that we were doing everything correctly,” he says.
What Cornish Lithium found sparked tremendous excitement: not only was the lithium still there, it was in the same concentration, 220 milligrams per litre of geothermal water, with concentrations of up to 260mg/L. This is an order of magnitude less than what you would get in South America, where it is possible to get 2,000 mg/L, but high enough that Cornish Lithium CEO Jeremy Wrathall immediately proclaimed it as “globally significant” and with the “potential for a new industry”. “It was very satisfying, definitely,” Matthews says.
“Adam was spot on, I think he was within ten metres of the predicted depth for the structure that we were interested in, which was crazy,” says Rebecca Paisley, an exploration geochemist at Cornish Lithium. To her, this type of geology represents the ultimate puzzle. “You don’t know the edges, and you don’t know how many pieces there are, and you don’t know what the shape is. And you have to piece everything together, which is what we’ve done with 3D modelling.” Unlike the china clay pits, geologists cannot assume that the granite stretches to a certain depth and will result in a specific volume of lithium. At present, she says, they do not know the recharge rates of the water to guarantee a steady amount of lithium. It’s a vast resource, we just need to put a number on it,” she says.
In this project, Matthews is the navigator, Salisbury is the scout, and Paisley plays the part of detective, looking at other sources that could give clues about what lies in the bedrock below. “My job comes in when we don’t have that data about the surface,” she explains. “If people have taken soil samples from the surface, and the soil is eroded rock, it will contain smaller pieces of the substance at the heart of the bedrock below. If you get something that is five times or ten times higher [than normal] then it sticks out like a sore thumb.”
At the moment, the drill campaigns are based on existing mine data, which means geochemistry has more of a supporting role, Paisley explains. “But in the future we would use it as we step away from mine data. That’s when we would do more surface exploration, which is not invasive; you’d collect a little bit of water from streams and so on and understand what’s happening there.”
Expanding this operation will be a far cry from the huge craters that previous mining left behind, Paisley says. All that’s required is a small shipping container in the corner of a field, perhaps a few small greenhouses exploiting the geothermal heat coming out of the holes, a heat exchanger and two boreholes, one shallower to extract the lithium and one deeper to put the water back into the ground.
It’s a big gamble. Unlike rock, water is hard to control; it can dilute and lose the concentration of lithium, and can move around. “When you are extracting lithium from the hard rock, there is much more certainty of the density of lithium. But there’s a huge challenge with what to do with the waste,” says Rich Crane, a senior lecturer in sustainable mining at Camborne School of Mines, a university in Penryn. If Cornish Lithium is able to make lithium brine extraction from geothermal waters viable, there will be less of an environmental footprint, he says. “What they are doing here in Cornwall is really, really novel. It’s not been done before. I can see a future potential for loads and loads of boreholes across the county, and in Devon as well.”
Scaling up the water extraction method to get more from each dig would be easier because it wouldn’t require loads of unsightly boreholes. “They are accessing fault lines that are naturally occurring very deep, kilometres away from the surface environment,” Crane says. “They can do it in a very non-destructive way. They are going to have these wells that will keep on producing water, because the whole system will recharge itself.”
TODAY, BY THE time you turn on the ignition of an electric car, the lithium-powered battery under the hood is likely to have already travelled around the world a few times. The battery elements are sourced from around the globe: lithium travels from South America or Australia, is sent to battery manufacturing facilities in places like China or Germany, then shipped to car manufacturers in its final form.
Data paints a grim picture of electric batteries’ current footprint. Vehicle consultancy Berylls Strategy Advisors estimates that manufacturing an electric car battery emits up to 74 per cent more CO2 than producing an efficient conventional car if it’s made in a factory powered by fossil fuels. According to Carbon Brief, around half the emissions from battery production come from the electricity used to manufacture and assemble them.
Lithium is one of the lightest elements in the periodic table, so transporting it is “neither here nor there in the overall equation of the energy needed to produce the chemicals for car batteries,” says Frances Wall, professor of applied mineralogy at the Cranborne School of Mines. She says that the real issue is the security of the supply. “The only people that are really processing lithium, even if it’s mined in South America or Australia, it’s been going off to China for the next stage of processing,” she says. “It’s not the miles of shipping that is the problem, it’s the fact that you are sending it away to China, which could then choose to sell it to someone else.” She argues that we will only be able to control the environmental footprint – and supply chain – if we have a local ecosystem to produce batteries in the UK.
Last year the European Commission forecast that Europe would need 18 times more lithium in 2030 against the current supply in order to meet demand for electric vehicle batteries. By 2050, it will need 60 times as much. The Commission expects the European Battery Alliance, a public and private investment, to “mobilise at scale” and “lead to 80 per cent of Europe’s lithium demand being supplied from European sources by 2025”. In the UK, a “green energy plan” is set to end the sale of new petrol and diesel cars and vans by 2030, ten years earlier than previously planned.
To support this, the British Government is investing £1.3 billion in a network of electric charging points and will be providing more than £1 billion in subsidies for the purchase of new electric vehicles and for battery production. Without localised battery production, manufacturers could face hefty EU tariffs within the next three years. In July, a House of Lords committee report urged ministers to secure the supply of these raw battery materials and build gigafactories to make batteries.
This means that Cornish Lithium and British Lithium have a little over four years to set up a viable commercial operation to meet growing demand. This is a hefty task: setting up a mine in locations like Australia or South America, where there is a proven supply of precious metals like lithium, can take an average of a decade, according to Rich Crane.
The battery gigafactories needed to process the supply are also unevenly distributed: China has 156, Europe has 22 and the US has 12, according to data from analysts at Benchmark. The Öko-Institut, a German research and consultancy institution, expects global demand to reach 220 gigafactories by as early as 2050. For now, the UK has none. After years of speculation (and brief hope that Tesla would set up a gigafactory here rather than in mainland Europe), Nissan has emerged with a plan to be the first. The car manufacturer has pledged to set up the UK’s first large-scale battery gigafactory in Sunderland, which will have capacity for 9GWh, producing batteries that will power “tens of thousands” of Nissan Leafs. At the time of writing, the gigafactory, which is owned by investor Envision AESC, has yet to be built and the company was unable to provide any details as to the logistics involved in the construction and sourcing of materials for the batteries it plans to produce.
Even if UK companies start extracting lithium and producing batteries, Wall says it’s important to make sure the metals don’t end up going to waste, and that old batteries are recycled. She hopes that European legislation, which could require a percentage of electric batteries to be recycled, could help to create a domestic market for battery recycling. “We need so much more lithium, for heaven’s sake let’s not go and mine it and chuck it all away again,” she says.
Back in the Cornish hills, the extraction companies hope that making raw materials and gigafactories public investment priorities will propel their expansion plans onward. The next step is to hire the people needed to scale up, says Cornish Lithium’s Lucy Crane. “At the moment we employ 21 people down here in Cornwall, we're all really technical, a lot of us have got master's degrees, and we've got PhDs,” she says. “That's not necessarily a route that's open to people who might have grown up in Camborne.” She’s passionate about providing careers for those in the local community as operations step up. And at the moment, it can’t happen fast enough: “The timeline for when we need to produce lithium is so short, we need to start producing the stuff yesterday.”
This article was originally published by WIRED UK
