A significant discovery has been made inside an extinct volcano near the Nevada-Oregon border. Researchers believe they may have uncovered the world’s largest lithium deposit, a find that could reshape the global dynamics of lithium supply.
A Potential Game-Changer for the U.S.
On August 30, 2023, a paper published in the journal Science Advances by researchers Thomas Benson, Matthew Coble, and John Dilles detailed their findings. They reported the discovery of what might be the largest known lithium deposit in the world, located inside the caldera of an extinct volcano in Nevada. The researchers suggest that the deposit could dramatically impact America’s capacity to produce batteries without depending on Chinese sources. Their paper highlights the potential of volcano sedimentary lithium resources, noting their shallow depth and high-tonnage deposits. The sediments within the southern portion of McDermitt caldera, specifically at Thacker Pass, contain extremely high lithium grades, surpassing other known global claystone lithium resources.
The researchers estimate that between 20 to 40 million tons of lithium metal are present within this volcanic crater, formed approximately 16 million years ago. This amount surpasses the deposits found beneath a Bolivian salt flat, previously considered the world’s largest. In 2020, the total demand for lithium worldwide amounted to 292 thousand metric tons of lithium carbonate equivalent. It is forecast that by 2030 this quantity will increase to approximately 2.5 million metric tons.
An analysis revealed that an unusual claystone, composed of the mineral illite, contains between 1.3% to 2.4% of lithium in the volcanic crater. This concentration is nearly double that found in magnesium smectite, a more common mineral than illite.
Anouk Borst, a geologist at Belgium’s KU Leuven University, commented on the discovery, stating, “If you believe their back-of-the-envelope estimation, this is a very, very significant deposit of lithium. It could change the dynamics of lithium globally, in terms of price, security of supply, and geopolitics.”
The Geological Story Behind the Deposit
The McDermitt Caldera, where the deposit is located, formed 16.4 million years ago following a massive volcanic eruption. The caldera was filled with erupted products of an alkaline magma rich in various elements, including lithium. Over time, a lake formed within the crater, accumulating sediments rich in clay. After the lake drained, another volcanic activity exposed these sediments to a hot, alkaline brine, rich in lithium and potassium. This process transformed the smectite in the southern part of the crater, known as Thacker Pass, into illite, resulting in a claystone rich in lithium.
Christopher Henry, emeritus professor of geology at the University of Nevada in Reno, described the material as resembling “brown potter’s clay,” emphasizing its high lithium content. He also noted the ongoing search for additional lithium deposits in the U.S.
Benson, one of the researchers and a geologist at Lithium Americas Corporation (LAC), mentioned that his company plans to commence mining by 2026. The extraction process will involve removing clay with water, separating lithium-bearing grains using a centrifuge, and then leaching the clay in sulfuric acid vats to extract the lithium. If the extraction process proves to be energy-efficient and not overly reliant on acid, the discovery could be economically significant. This could ensure a steady supply of lithium for the U.S., alleviating concerns about potential shortages.