In the high desert along the Nevada-Oregon border, a quiet basin formed by an ancient supervolcano is quickly becoming a global focal point. Hidden under the McDermitt Boiler lies that scientists now believe to be the The largest lithium deposit in the known world.the element driving the battery revolution behind electric vehicles, smartphones and renewable energy storage.
This site, called Thacker PassIt is already changing the way geologists think about the formation of minerals in volcanic terrain. The first findings estimate that the deposit could contain 20 to 40 million metric tons of lithium—potentially more than double that of Bolivia Uyuni Salt Flatslong considered the largest fountain on the planet. If confirmed and fully extracted, the lithium buried here could power hundreds of millions of electric vehicles and make the United States a key player in the clean energy economy.
But the mine is at the center of a collision between mineral demand and environmental and cultural preservation. The project, backed by billions in federal support and associations from major automakers, faces growing pushback from Indian tribes and environmental advocates. What is at stake is not just a treasure trove of critical minerals, but a national test of how far the United States is willing to go to secure its clean energy future.
The cauldron with a trillion-dollar core
He McDermitt Boiler It spans more than 1,000 square kilometers and was formed 16 million years ago by a massive volcanic eruption. Over time, volcanic ash and mud accumulated in the center of the basin, creating lakebed clays rich in lithium-bearing minerals. Recent research published in Scientific advances revealed that post-eruption hydrothermal fluids transformed magnesium-rich smectite into illitea potassium-bearing clay that contains significantly higher concentrations of lithium, up to 2.4% by weight in some areas in Thacker Pass.
The scale of this lithium enrichment is unparalleled. Traditional lithium clay deposits average less than 1% lithium content; At Thacker Pass, the illite layer alone is approximately 100 feet thickshallow enough to open pit miningreducing operational complexity and cost.
Unlike lithium from brines or hard rock, clay-housed lithium poses unique challenges. The metal is chemically bound within mineral structures, requiring more intensive research. extraction process that involve leaching and chemical washing. Still, the shallow geometry and unusually high grades at Thacker Pass offer a low strip ratiowhich translates into Less waste rock per ton of lithium.—a critical metric for mining viability.
The formation, mineral composition and access of the site have positioned it as one of the most promising. critical mineral deposits in North America.
Billions in backup and a battery race at stake
The United States Department of Energy has approved a Loan of 2.23 billion dollars to fund construction at Thacker Pass, part of the Biden administration’s push toward onshore clean energy supply chains. The financing was granted through the Manufacturing of advanced technology vehicles program and is among the largest ever awarded to a lithium project.
Project developer Lithium Americas Corp. began construction in 2023 and aims to reach 40,000 metric tons of annual lithium carbonate production in its first phase. Production will be expanded in stages until finally reaching 160,000 tons per year in five phases, according to the company official technical report. The entire operation is expected to cover 85 yearsmaking it one of the longest-lived lithium assets in the world.
To ensure battery supply, general motors has entered a 20 year purchase agreement for 100% of Phase 1 production and a significant portion of Phase 2. GM also owns a 38% shareholding in the project.
Despite support from Washington and Detroit, the project remains divisive. Tribal communities, including members of the Fort McDermitt Paiute and Shoshone Tribehave expressed concern about the potential impact of the mine on ancestral lands, springsand archaeological sites. A coalition of tribes and environmental groups has filed legal challenges, some still pending, against the Bureau of Land Management’s 2021 Record of Decision approving the mine.
Geology reinvented: lithium in volcanic basins
Thacker Pass challenges conventional thinking about lithium geology. Until recently, global lithium production was dominated by spodumene pegmatites (hard rock in Australia) and evaporite brines (South American salt flats). McDermitt Caldera adds a new category to the mix: volcano-sedimentary lithium systemsformed through a mixture of magma chemistry, closed-basin lacustrine environments, and long-lived geothermal circulation.
In McDermitt’s case, peralkaline magmas Rich in sodium and potassium helped retain lithium during cooling, making the surrounding ash and tuff very fertile for clay formation. The resurgent movement of the magma fractured the overlying rock, creating conduits for hot fluids that concentrated lithium in illite deposits, especially in the southern portion of the caldera, where Thacker Pass is now located.
These findings suggest that similar caldera basins could contain untapped lithium potential. Geologists are now reviewing other resurgent volcanic systems in the American West and abroad, seeking the same combination of mineralogy and heat-driven alteration. The discovery marks a change in critical mining exploration strategies as lithium demand accelerates.
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