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Strategically, the United States has under its feet what could be the world’s largest lithium deposit: the McDermitt Caldera, an extinct supervolcano from about 16.4 million years ago, on the border between Nevada and Oregon.
The current estimate of reserves at Thacker Pass, the project’s main site, reaches 44.5 million tonnes in lithium carbonate equivalent (LCE).
According to an official report, the number was confirmed in an official NI 43-101 report by Lithium Americas Corporation, with a database date of December 31, 2024.
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In the U.S., the most powerful city on the planet is silently sinking every year: radars detect the ground subsiding more than 10 mm per year in areas of Washington, while scientists warn of risks to the American capital’s infrastructure.
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In the U.S., the most powerful city on the planet is silently sinking every year: radars detect the ground subsiding more than 10 mm per year in areas of Washington, while scientists warn of risks to the American capital’s infrastructure.
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In the U.S., the most powerful city on the planet is silently sinking every year: radars detect the ground subsiding more than 10 mm per year in areas of Washington, while scientists warn of risks to the American capital’s infrastructure.
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The Brazilian Air Force now has a colossal helicopter: the H125 from the TH-X project arrives with multi-mission technology, capacity for up to 6 occupants, high efficiency in military training and operation in extreme environments, strengthening the training of pilots for the FAB and the Brazilian Navy.
For the entire caldera, the theoretical ceiling calculated by Castor and Henry and cited in a paper published in Science Advances in September 2023 reaches 120 million tonnes.
For comparison, Bolivia, owner of the Salar de Uyuni, declares 21 million tonnes. Chile and Australia together do not add up to 20 million.
Even the raw lithium recently announced by the USGS in the Appalachians, in 2026, stands at 2.3 million tonnes.
The numbers for the Thacker Pass project, according to Lithium Americas, General Motors, and the U.S. Department of Energy, tell the story in five points:
- 44.5 million tonnes LCE in measured and indicated resources at Thacker Pass
- 20 to 120 million tonnes in total potential estimate for the McDermitt Caldera
- Up to 2.4% lithium by weight in Thacker Pass illite layers, compared to <0.4% global average
- US$ 2.26 billion in loan from the U.S. Department of Energy to accelerate production
- 1.6 million electric cars per year in battery with full production (Phases 1 and 2)
How the McDermitt supervolcano stored the world’s largest lithium deposit
According to USGS data, the McDermitt Caldera is one of the first volcanic structures of the hotspot that today feeds the Yellowstone supervolcano.
It is approximately 45 kilometers north to south and 35 kilometers east to west, forming an oval basin in the semi-arid landscape of the Nevada-Oregon border.
In geological terms, the caldera was formed when a rhyolitic lava dome catastrophically collapsed between 16.37 and 16.41 million years ago.
The resulting hole was filled with water and became an ancient lake surrounded by crater walls.
This lacustrine setting was key to the extreme concentration of lithium. Hot hydrothermal fluids, with temperatures between 200 and 300 degrees Celsius, circulated within the basin carrying dissolved lithium in high concentration.
According to the 2023 paper, these fluids transformed primary lithium-smectite minerals into lithium-illite, which is more stable and capable of retaining more ions.
In parallel, the closed basin had no drainage to rivers or streams, so the lithium never escaped.
In terms of mining, this means the parent rock is clayey and greenish-gray, not the wet salt of the Andes or the hard granite of Australia.
What makes Thacker Pass lithium up to 6 times more concentrated than normal
In sedimentary lithium deposits worldwide, the average concentration in the total rock is below 0.4% by weight.
At Thacker Pass, according to measurements from five core samples published in Science Advances, the illite carries between 1.3% and 2.4% lithium by weight. In ppm, the average in the ore reaches 18,000 parts per million.
According to geologist Anouk Borst, from KU Leuven University (Belgium), one of the study’s authors, the explanation lies in a secondary hydrothermal alteration rich in fluorine, lithium, potassium, and rubidium.
The process had never been described in scientific literature before the work of Borst’s team and Thomas Benson, chief geologist at Lithium Americas.
In practical terms, the high-concentration band is about 30 meters thick. Therefore, open-pit mining can extract the very high-grade ore without moving mountains of barren rock.
According to Philipp Ruprecht, a geologist at the University of Nevada in Reno, “many basins formed by volcanism are not particularly rich in lithium.”
However, in the case of McDermitt, the combination of a resurgent dome, a closed lake, and persistent hydrothermal fluids over millions of years created a unique case on the planet.
The result is that, in the same volume of rock, Thacker Pass delivers about six times more lithium than a common clay deposit.
In mine economics, this is the difference between comfortable profit and loss.
Bolivia, Chile, Australia, and Brazil fall behind the world’s largest lithium deposit
The Salar de Uyuni, in Bolivia, held the title of the largest known lithium reserve for decades.
Bolivia today declares 21 million tonnes in metallic equivalent, more than double the country’s previous estimate.
The Atacama Desert, in Chile, has between 9 and 10 million tonnes in recoverable resources.
The two South American operations work by brine evaporation in giant pools, a process that demands a lot of water in a dry region.
In parallel, the Australian Greenbushes mine, currently the world’s largest hard-rock operation, produces about 1.95 million tonnes of spodumene per year.
Its reserves reach 6.8 million tonnes LCE, a base well below Thacker Pass.
According to the USGS, Brazil is the sixth largest global producer of lithium. National production, concentrated in the Jequitinhonha Valley (Minas Gerais), reached 51,694 tonnes LCE in 2025, with a projection of 63,757 tonnes in 2026.
In strategic terms, there is an embarrassing detail: about 99% of Brazilian lithium in 2025 was exported to China for processing.
Sigma Lithium accounts for almost 70% of the Brazilian spodumene market.
CPG has already covered the Brazilian challenge in other articles on dependence on production chains in strategic sectors such as military and energy.
GM, DOE and battery for 1.6 million electric cars per year
Lithium Americas Corporation holds a 62% stake in Thacker Pass and acts as the project manager.
General Motors entered with 38% and invested US$ 625 million in a combination of cash and credit letters, an announcement formalized in 2024.
The U.S. Department of Energy, through the ATVM (Advanced Technology Vehicles Manufacturing) program, closed a US$ 2.26 billion loan in 2024 to accelerate Phase 1.
According to Lithium Americas, the total capex for the initial phase is between US$ 1.3 and 1.6 billion.
Phase 1 targets 40,000 tonnes of battery-grade lithium carbonate annually, enough to supply about 800,000 electric vehicles per year.
Phase 2, currently in design, doubles this capacity to 80,000 tonnes, serving 1.6 million cars.
According to Jonathan Evans, CEO of Lithium Americas, commercial production is expected to begin in late 2027. Detailed engineering was 93% complete and equipment procurement 60% complete by the end of 2025.
In parallel, the construction site already has 950 people, a number that will reach 1,800 at the peak of construction in 2026.
What the Paiute Shoshone tribe thinks of the world’s largest lithium deposit
According to local records, the Thacker Pass site has another name for the indigenous people of the region: Peehee Mu’huh, which means “rotten moon” in Paiute, referring to a massacre of Northern Paiute tribe members by European immigrants in September 1865.
According to the Fort McDermitt Paiute and Shoshone tribe, the site is sacred and contains burial grounds. In parallel, the Reno-Sparks Indian Colony and the Burns Paiute tribe also oppose the project.
The tribes filed lawsuits in federal court questioning environmental permits and prior consultation protocols.
In parallel, the courts authorized the continuation of construction, but opposition remains active. According to indigenous leaders, the project could contaminate sacred aquifers and destroy an ancient burial site.
Lithium Americas, in turn, states that it complies with all federal consultation protocols and has invested in environmental mitigation programs.
According to Evans, the company “respects the cultural importance of the site and is in permanent dialogue.”
What changes in the US vs. China game and where Brazil fits in
Strategically, China currently processes about 67% of the world’s lithium and holds only 8% of global reserves.
Therefore, the U.S. depends on China for more than 70% of refining, even when the raw material comes from other countries.
According to sector analyses, Thacker Pass is the first serious American attempt to close the chain: extract lithium at home, process at home, assemble batteries at home, sell electric cars at home.
The Inflation Reduction Act of 2022 already provides tax benefits for projects with a domestic supply chain, a logic also present in the military effort to Americanize production, as covered by CPG’s coverage of the US Navy’s LOCUST laser.
In parallel, in May 2026, the USGS announced another significant deposit in the Appalachians, with 2.3 million tonnes of lithium oxide.
This discovery, according to Fortune’s calculation, is equivalent to 328 years of American imports at the 2024 rate.
Therefore, for Brazil, the equation is uncomfortable. The country has reserves in Minas Gerais, but exports practically everything raw to China.
The U.S., meanwhile, is creating a direct competitor that solves the raw material bottleneck and also controls processing.
It should be noted, however, that the commercial production schedule for Thacker Pass Phase 1 is late 2027, according to Lithium Americas’ guidance in February 2026.
This article will be updated with confirmation of the effective start of operation and with new USGS data on comparable reserves.
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