Weardale Lithium Wells
LIKE O’Rafferty’s motor car, lithium and the church redevelopment are the burning questions of the
day in every public bar, “it’s all gone quiet at Eastgate” someone said to me this week, “what do you
think is happening?”
So, I read the articles published in the Gazette a few weeks ago and the reply from Weardale
Lithium (WLi) and press releases and publicity from WLi and Northern Lithium (NLi) as well as stuff
from the County Council and reports in geological journals. Then I sat down and did the sums, which
I’ve outlined below to see why it might have all gone quiet and whether noise might be in the offing.
Lithium is a volatile product on world markets. At the start of August 2025 lithium carbonate (a
common form of traded “battery grade lithium”) was selling at $8,500 a tonne. Today, thanks to the
suspension of operations at a Chinese mine, the price is $11,500. In 2023 the price peaked at almost
$80,000 a tonne, but ten years ago it was about $10,000 a tonne. Prices are given in US dollars, and
the current dollar-sterling exchange rate is 1 dollar will get you about 75p. I have used $10,000 a
tonne in my calculations.
Both companies, NLi and WLi, suggest they will each extract at least 10,000 tonnes of “battery
grade lithium” a year with WLi aiming for 20,000 tonnes. “Battery grade lithium” isn’t lithium itself
but lithium carbonate in the case of WLi, or lithium chloride/sulfate in the case of NLi which will
need further processing. These lithium compounds respectively contain about 16 and 19%
elemental lithium, so just shy of 20%, which for 10,000 tonnes of battery grade lithium is about
2,000 tonnes of elemental lithium itself (or 6,000 tonnes of elemental lithium to make 30,000 tonnes
of battery grade lithium if NLi and WLi’s aspirations are achieved).
At $10,000 per tonne ($10 per kilogram) 10,000 tonnes of lithium carbonate would be worth
$100 million (£75 million) on the world market. 30,000 tonnes $300 million but back in 2023 at the
peak of the market 30,000 tonnes would be almost $2.4 billion. Seems like a pretty good investment
even at $10,000 a tonne, so why isn’t the money flooding into Weardale?
The companies say that the lithium concentration in the Slitt Vein brine is 100 mg/l, (the
published figure for the Eastgate No 1 borehole is 92 mg/l but there are no free access data for the
Ludwell Farm boreholes that I can find). 1 mg/l = 1 milligrams per litre and as there are 1000
milligrams in a gram and 1000 litres in a cubic metre, 100 mg/l is the same as 100 grams per cubic
metre or 1 kilogram of elemental lithium for 10 cubic metres brine and therefore at 100% recovery
1 tonne of elemental lithium would be obtained from 10,000 cubic metres of brine and would make
about 5 tonnes of battery grade lithium.
Northern Lithium say their recovery was 92% at 96.5% purity multiplied together gives a recovery
of 89% and if we factor in the lithium concentration being 92 mg/l not 100 mg/l it falls to 82%. So
effectively you get 1 kg of elemental lithium from 12,000 cubic metres of brine. I’ve not reduced
everything by 20% but have assumed 100% recovery of 100% pure material from 100 mg/l lithium
brine.
A cubic metre of water weighs a tonne, but a cubic metre of the brine weighs a bit more as there
are about 45 kg of other salts, mostly sodium chloride (“table/road salt”) in each cubic metre of
brine.) Doing the sums: as 1 tonne of elemental lithium comes from 10,000 cubic metres brine and
as they are both aiming for at least 2,000 tonnes of elemental lithium (so they can both make
10,000 tonnes of battery grade lithium per year) they will both need to pump 20 million cubic
metres of brine every year (the extra 45 kg of salt has now become almost 1 million tonnes). Of
course, if WLi is trying to get 20,000 tonnes of battery grade lithium by themselves they alone will be
pumping 40 million cubic metres of brine (containing almost 2 million tonnes of salt). 20 million
cubic metres of water is 8,000 Olympic swimming pools or a little over 600 litres per second which is
two or three typical bathtubs of water a second.
After pumping it out and removing the lithium the spent brine needs to be disposed of
somewhere. It can’t be cleaned up and pumped into the river because the companies would
somehow have to dispose of 2 or 3 millions of tonnes of salt every year (a million tonnes of salt
would fill the road between Stanhope and Crook to a depth of around 4 m) and, for the 30,000
tonnes option, the amount of treated water pumped to the River Wear would be larger than the
flow at Stanhope ‘fish jump’ for 60% of the year so the flow in the river for much of the year would
be treated effluent.
Can the spent brine be tankered away? This plan was reported in the Gazette in February for
WLi’s pilot plant which would run at between 10 and 350 cubic metres per hour (the upper figure is
unlikely but not ruled out). Weardale Lithium’s plan is that all the water pumped from the borehole
(Eastgate No 1) to the pilot plant would be removed from site for treatment by Northumbrian Water
at Teesside – it is a 100 mile round trip Eastgate to Bran Sands and back, a journey that takes me
almost 3 hours in the car. A big road tanker holds 40 cubic metres (about 40 tonnes of brine) and at
10 cubic metres and hour pumping 24/7 that would be 84 tanker movements a week (42 in and 42
out) or 15 a day for a five-and-a-half day, 55 hour, week, equivalent to one tanker up or down the
dale every 40 minutes, 8 round trips a day, and not too big a burden on the A689.
However, planning report DM/22/02878/MIN says that says that the biggest tankers to be used
at the Ludwell Farm site will be 13 cubic metres which would be 260 tankers movements a week
(130 in and 130 out) and for a five-and-a-half day week that is 52 movements a day, one about every
13 minutes. (Remember, the brine pumps run 24/7 while the tankers run for 55 hours a week.) It
isn’t specified what size tankers WLi will use but it doesn’t take much imagination to see that should
the pilot plant reach its upper limit of 350 cubic metres per hour (as given in the planning
permission) there would be 3,000, 40 cubic metre, tanker movements a week or 1 every minute for
a five-and-a-half day week (assuming instantaneous turnarounds at Eastgate and Bran Sands). Using
13 cubic metre tankers there would be no other traffic on the road.
How was this ever included in the planning application and how did the council come to approve
it? Even at 40 cubic metres an hour a tanker would be rumbling up or down the road every 10
minutes which would be unbearable and unsafe. The cost of hiring all these vehicles and drivers
would be immense as even at 10 cubic metres an hour from the well (the minimum pumping rate)
you would need 3 vehicles working solely on this job assuming 2 or 3 trips a day each and no
breakdowns.
Let’s look at the economics. It was noted previously that there is 1 kg of elemental lithium in
10 cubic metres of brine so a 40 cubic metre tanker would take enough spent brine to yield 4 kg of
elemental lithium, which ignoring all production losses, is equivalent to 20 kg of battery grade
lithium. Recall that the price of battery grade lithium is currently about $10 per kilogram so one
tankerful of brine has yielded $200 (£150) in cash with which to extract and sell the lithium, drive the
effluent tanker to Eastgate, load up the effluent, drive to Teesside, off-load and pay Northumbrian
Water to deal with it.
However much brine you pump from the ground the economics of using tankers doesn’t change
because the amount of lithium in a cubic metre of groundwater is fixed by the concentration in the
Slitt Vein at 0.1 kg elemental lithium per cubic metre (0.5 kg battery grade lithium) with a value of $5
at today’s price. If you take into account the production losses the economics are even worse.
If the river and road tankers can’t be used to dispose of the brine the only alternative is
reinjection back into the ground. Weardale Lithium’s plan is reinjecting into their Eastgate No 2
borehole while Northern Lithium intends injecting into unspecified boreholes at Ludwell Farm (as
they did during their recent 60-day pump test).
Weardale lithium are aiming for 6 tonnes of lithium carbonate a year (1.2 tonnes of elemental
lithium) during the field trials and 1,000 tonnes per year (200 tonnes of elemental lithium) during
the pilot plant phase. To make 6 tonnes of lithium carbonate a year requires only 12,000 cubic
metres of brine which, over a year, is an average pumping rate of 1.4 cubic metres per hour or
0.4 litres per second (a little under twice the flow from our kitchen tap) whereas 1,000 tonnes per
year requires 2 million cubic metres to be pumped at a rate of about 230 cubic metres per hour or
64 litres per second (at this production rate there would be 1 tanker movement up or down the dale
every 100 seconds, 35 movements an hour). (The proposed lower and upper limit pumping rates of
10 and 350 cubic metres an hour in the planning application would produce about 43 and
1,500 tonnes in a year). Why then use road tankers at such immense cost if the brine can be
returned to the ground?
When Eastgate No 1 borehole was drilled it was pump tested at 37 cubic metres an hour for 24
hours with most of the water coming from an unmineralized cavity at 411m which, it turned out
during testing, was isolated from the remaining 580 m of the borehole. This lower 580 m produced
less water than the cavity at 411 m and was tested at 21.5 cubic metres an hour, again for 24 hours.
Not much of a test on which to make a long-term assessment of the available lithium resource – but
the boreholes were not drilled to prospect for lithium but to investigate subterranean heat flow.
Eastgate No 2 borehole was drilled off the Slitt Vein to a depth of 420 m deep and was cased with
steel to the top of the granite at 286 m. There is therefore only 134 m of granite into which the
effluent brine could be injected, but the borehole did not find the cavity at 411 m and produced very
little water. It was noted that the granite was of uniformly low permeability. The simple fact is that
it would not be possible to inject all but a small volume of water into Eastgate No 2 borehole and
hence the need for enormously expensive tankers during the pilot testing phase.
What happened with Northern Lithium’s 60-day pumping test? They reported treating 3.5
million litres of brine. Quoted in this way it seems rather a lot, but 3.5 million litres are only 3,500
cubic metres and averaged over 60 days that is a pumping rate of a little under 0.7 litres per second
(but still almost three times the flow of our kitchen tap). At 100% recovery, 3,500 cubic metres
would have produced 350 kg of elemental lithium equivalent to about 1.75 tonnes of Battery Grade
lithium with a value of $17,500 which works out at about $300 a day for a 24 hour day or about £230
at today’s exchange rate day.
So, in 60 days NLi treated 3,500 cubic metres of brine in, we are informed, a 1:15 scale pilot plant
suggesting that the full-sized plant would treat 52,500 cubic metres every 60 days or 1.3 million
cubic metres a year and that would yield about 160 tonnes of Battery Grade lithium worth around
$1.6 million at today’s prices. It is however a long way short of the stated 10,000 tonnes a year and
yet, based on this tiny pump test, NLi are confident they can extract even more than 10,000 tonnes a
year from wells spread across the Pennines.
Reinjection of the spent brine, as in the 60-day test, is the only viable option, and it is a crucial
factor as the brine cannot be extracted at a rate greater than that at which it can be reinjected. We
know that WLi would rather use tankers even for small abstraction rates and that NLi managed
around 60 cubic metres a day in their 60-day pump test, but in order to produce 10,000 tonnes of
Battery Grade lithium a year each company would need to reinject 55,000 cubic metres a day, every
day, day-in, day-out, 24/7. That is about 1,000 times more than has been proven. So, at what rate
could water be reinjected without fracking the rock?
The biggest injection scheme in the country is the North London aquifer recharge scheme which
runs for four to five months of the year and is capable of recharging 60,000 cubic metres per day
through 30 boreholes into the Chalk and Thanet Sands. The Chalk is the most important aquifer in
the country supplying over 75% of drinking water to the South East and on average each recharge
borehole has the capacity to inject about 2000 cubic metres of water per day (about 85 cubic metres
and hour) for about 150 days. Averaged over the year that’s about 35 cubic metres and hour – or
three-and-a-half times the lower rate and ten-times less than the upper rate for the proposed
Eastgate pilot plant. So, if the most important aquifer in the country only manages 85 cubic metres
an hour at peak operation what can we expect of granite?
In Europe there are several geothermal sites where water is reinjected into sandstone/granite,
although the boreholes are much deeper than the Eastgate boreholes – around 3 to 4 km compared
to less than a kilometre at Eastgate. Some are currently being assessed for lithium production as the
lithium concentrations in the brines are about twice that in the Slitt Vein and it is suggested that
1,000 tonnes of lithium carbonate could be obtained with a pumping/injection rate of 50 l/s
(180 cubic metres per hour) and a lithium concentration in the brine of 200 mg/l and a 70%
extraction rate plus fewer operating hours.
At the Landau site Vulcan Energy are planning 24 extraction and injection wells to yield 24,000
tonnes of lithium hydroxide monohydrate (about 17% lithium) a year so, about 1,000 tonnes of
lithium carbonate per well or 200 tonnes of elemental lithium a year. Vulcan Energy it seems think
they can get 1,000 tonnes of battery grade lithium from brines with twice the Eastgate lithium
concentration using wells four-times deeper. Yet NLi and WLi think they can get at least 10,000
tonnes from their relatively shallow wells. Is this realistic?
Perhaps the intention is to drill boreholes all along the Slitt Vein so that it bristles with wellheads
like oil wells sprouting in the desert. That seems to be NLi’s intention as they announced recently
based on the 60-day pump test: “The results of our recent tests and trials have confirmed that
Northern Lithium now has the opportunity and potential to scale up supply, within the next decade,
to significantly more than our current base case target of 10,000 tonnes of battery-grade lithium
delivered per year from a series of production sites across the Northern Pennine Orefield.”.
Therein lies the clue. The plan appears to be that, based on the one-and-a-half swimming pool
pump test, within the next ten years the Northern Pennines will be criss-crossed by pipelines
running to and fro between abstraction wells, treatment plants and injection wells carrying a toxic
brine that in the event of a breakage would cause untold damage to the moorland and riverine
ecosystems. At current lithium prices I very much doubt that I will live to see it.
But is the resource even there in the first place? In June the Gazette had a headline: ‘Huge’
lithium reserves prompts extraction plan, but I can’t find an estimate of the reserve let alone how
much of it would be extractable after all, up to 30,000 tonnes and more a year must be based on
something. Let’s give it a go.
The Slitt Vein is about 20 kilometre long and a few metres wide, let’s say 100 m, and let’s say that
all the water could be extracted from the Slitt Vein in the manner of dewatering the coalfield to a
depth of a kilometre depth below the 400 m mark, where the lithium concentration hits near
enough 100 mg/l. The volume of rock is therefore around 2 billion cubic metres (20,000 m times
1,000 m times 100 m), but how much water is there that contains lithium brine? Typically, granite
would have a porosity of around 1% in the bulk rock and the drilling logs for Eastgate No 1 do not
indicate anything special below the 411 m cavity. Recall that Eastgate No 2 had uniformly low
permeability and both permeability and porosity tend to decrease with depth due to increasing
overburden pressure.
Let’s say the granite has 5% connected open space (effective porosity) which gives a water
volume of 100 million cubic metres which at 0.1 kg per cubic metre is 10 million kilograms or 10,000
tonnes of elemental lithium which is equivalent to 50,000 tonnes of battery grade lithium. And that,
you might notice, is less than 2 years resource at the much talked about production rate of 30,000
tonnes and more battery grade lithium a year. To get this 50,000 tonnes the entire 20 km of the Slitt
Vein would need to be dewatered (and treated at 100% efficiency) and all that water reinjected in
such a manner that it doesn’t flow back to the Slitt Vein otherwise it will dilute the resource meaning
that more water would need to be pumped to maintain the yield (with the coalfield they just
chucked the water away).
I suggest that it is infeasible to do this and that the numbers being quoted by the lithium
companies are a pipe dream worthy of Lewis Carroll’s caterpillar. But, I expect that I will soon be
told where my sums have gone wrong and reassured that I will not be spending my twilight years
gazing across the expanse of the North Pennines bristling with brine wells and pipelines that
disappear over the horizons in star-like manner towards Teesdale, Alston, Blanchland and Bollihope,
or for that matter dodging wagons nose to tail rumbling up and down the A689 shaking the house to
its foundations.
Via email, name withheld
