Lithium, the key element in the net-zero carbon drive through its applications in car batteries, EVs, energy storage, mobile phones, and other electronic devices, is forecast to play a significant role in clean energy for years and decades to come. China is undoubtedly the main global supplier of this element, with Australia and Chile being the main producers. If we look at the USA, it has been left far behind in this race, and produces only less than 1% of the global supply. As of December 2025, Silver Peak in Clayton Valley, Nevada, is the only fully operational lithium mine in the country, which is owned and operated by Albemarle, and produces approximately 4,000 to 5,000 metric tons of Lithium Carbonate Equivalent (LCE) annually.
The US government in recent years have paid great attention to the local supply of critical minerals, reducing dependency on imports from China, and to secure the supply of materials for its versatile industrial, domestic and defence needs. In this regard, several lithium exploration projects have recently been initiated by different companies, and the Thacker Pass lithium project in Nevada has emerged as the standout project.
It is operated by Lithium Americas Corp. (LAC) with 68% interest, whereas General Motors (GM) holds the remaining 38% stake. The U.S. government, through the Department of Energy’s (DOE) Advanced Technology Vehicles Manufacturing (ATVM) Loan Program, provided a loan of approximately $2.26 billion to Lithium Americas for the project. The first $435 million tranche was drawn in late 2025. In 2025, the government negotiated to take a direct 5% equity stake in Lithium Americas. General Motors has priority rights to 100% of Phase 1 production for 20 years.
Geological perspective:
Thacker Pass is different from major lithium mines around the world, for instance, like in Australia and Chile, where they mostly produce from hard rocks (granite) and brines respectively, whereas at Thacker Pass it would be from sedimentary rock’s clay minerals – mainly smectite and illite.
The Thacker Pass deposit is a volcano-sedimentary lithium deposit located within the southern portion of the extinct McDermitt Caldera. The origin of the McDermitt Caldera is a result of 1,000 cubic km of massive lithium-rich volcanism, caused by the Yellowstone hotspot, which took place around 17 million years ago. Volcanic ash and tuff accumulated in a caldera lake, where cooling of tuff and leaching of lithium from the tuff produced lithium-rich smectite minerals. Smectites from McDermitt average about 0.3% lithium metal, significantly higher than the typical 0.1% found elsewhere.
As smectite continued to accumulate, magmatic resurgence reactivated the magma chamber, uplifting and fracturing caldera lake sediments without an eruption. Approximately 100,000 years after the first massive eruption, lithium-rich hydrothermal fluids then moved through these fractures and transformed smectite into illite clay mineral. Illite at Thacker Pass averages about 1.8% lithium metal, making it an exceptionally lithium-rich mineral. Later sedimentation and minor eruptions buried the deposit, but erosion eventually exposed the illite at the surface.
Reseves and Resources:
As of 2025, Thacker Pass is recognised as hosting the largest known measured lithium reserve and resource in the world. Following an updated technical report effective December 31, 2024, total Reserves (Proven & Probable) stand at 14.3 million tonnes of Lithium Carbonate Equivalent (LCE). The average grade is reported as 2,540 ppm lithium, and these reserves are enough for around an 85-year mine life.
The total mineral Resources (Measured & Indicated) are reported as 44.5 million tonnes of LCE, with an average grade of 2,230 ppm lithium. The Inferred Resources contain an additional 21.6 million tonnes of LCE.
Development
The Thacker Pass lithium project will be developed in five phases, reaching a total production capacity of 160,000 tonnes per annum (tpa) of battery-grade lithium carbonate. The Phase-1 construction began in March 2023, and as of December 2025, it was still in progress and targeted for completion in late 2027 – the full production is scheduled to begin in 2028. The development activities would include initial mine pits, a sulfuric acid plant, and the primary processing facility. Once fully operational, Phase 1 will produce 40,000 tpa of battery-grade lithium carbonate annually, which could support the production of batteries for up to 800,000 electric vehicles.
Phases 2 and 3 will each add 40,000 tpa, bringing total capacity to 120,000 tpa, with construction expected roughly four years apart. Phase 4 includes the construction of a direct rail line from Winnemucca to Thacker Pass. Phase 5, planned concurrently with Phase 4, will expand capacity to 160,000 tpa through a larger sulfuric acid plant and an additional processing facility.
Lithium extraction technology
The Thacker Pass project uses a specialised sulfuric acid leaching method to extract lithium from sedimentary claystone. Unlike traditional brine evaporation (common in South America) or hard-rock spodumene mining (common in Australia), this process is optimised for the unique high-grade clay found in the McDermitt Caldera.
The extraction and processing involve several key stages. Raw ore is excavated through open-pit mining, which is then crushed and mixed with water to create a slurry. It then goes through additional mechanical processes to separate the lithium-rich clay from non-lithium-bearing sand and gravel. The concentrated clay slurry is then placed in stirred reactor vats where it is mixed with sulfuric acid. The acid breaks down the clay structure, releasing lithium into a liquid solution (brine) within a few hours.
Then the impurities are removed from the solution through neutralisation using limestone, whereas magnesium, potassium and sodium are removed through crystallisation and the ion exchange method. Magnesium sulphate (Epsom salt) is a significant byproduct at this stage. The last step is the precipitation of battery-grade lithium carbonate, which is achieved through adding Soda ash (Na2CO3) to the purified lithium sulphate solution.
The facility at Thacker Pass is designed to recycle more than 85% of the water used during processing. The entire transformation from raw clay to battery-quality lithium carbonate is projected to take less than 24 hours.
How is Thacker Pass geology different from other major global lithium projects?
The Thacker Pass lithium project is distinct from other major global deposits in its origin, mineralogy, and grade. While most global production comes from hard-rock pegmatites or continental brines, Thacker Pass is a volcano-sedimentary deposit.
Australian hard-rock mines like Greenbushes host lithium in spodumene or lepidolite minerals within pegmatites, which are much harder and require high-heat calcination (roasting) to extract the lithium. In South America, lithium is produced from brine (Salars) found in underground saltwater, but this process takes a very long time because the water must slowly evaporate.
Thacker Pass is the most lithium-rich sedimentary deposit known. Typical clay lithium deposits (e.g., Clayton Valley, Rhyolite Ridge) contain about 2,400 to 2,800 parts per million (ppm) of lithium, but the Thacker Pass deposit averages about 12,000 ppm. This is similar to the lithium levels found in hard-rock pegmatites, which typically range from 5,000 to 15,000 ppm, but without the need for hard-rock mining. By comparison, lithium concentrations in brine deposits in Chile and Argentina are much lower.
Conclusion
Thacker Pass is the largest known lithium deposit in USA, and it will provide a major domestic source of lithium, which is needed to make batteries for electric vehicles and energy storage. This helps reduce dependence on foreign suppliers, especially China, and strengthens U.S. energy independence. The project is expected to create about 2,000 jobs during construction and operations, boosting the local Nevada economy. Once mining begins, it could generate more than $2.1 billion in economic activity each year for the region.
By producing lithium in the U.S., the project will make the supply chain more secure and reduce reliance on foreign competitors. This gives the U.S. more control over its energy future and lowers geopolitical risks.
Thacker Pass also uses new and more environmentally responsible mining methods. It focuses on extracting lithium from clay, reusing water, and reducing environmental impact. If proven successful on a commercial scale, this approach could be used at similar lithium deposits across the country, especially in the western U.S.
