South Dakota may miss out on the lithium boom. The folks drilling for that vital battery metal in the Black Hills may all want to pull up stakes and head to the Thacker Pass on the Nevada-Oregon border, where miners think they’ve found a huge lithium deposit in a volcanic crater:
An estimated 20 to 40 million tonnes of lithium metal lie within a volcanic crater formed around 16 million years ago. This is notably larger than the lithium deposits found beneath a Bolivian salt flat, previously considered the largest deposit in the world.
‘If you believe their back-of-the-envelope estimation, this is a very, very significant deposit of lithium,’ says Anouk Borst, a geologist at KU Leuven University and the Royal Museum for Central Africa in Tervuren, Belgium. ‘It could change the dynamics of lithium globally, in terms of price, security of supply and geopolitics.’
New in situ analysis reveals that an unusual claystone, composed of the mineral illite, contains 1.3% to 2.4% of lithium in the volcanic crater. This is almost double the lithium present in the main lithium-bearing clay mineral, magnesium smectite, which is more common than illite [Anthony King, “Lithium Discovery in US Volcano Could Be Biggest Deposit Ever Found,” Chemistry World, 2023.09.06].
Currently the largest known lithium deposit is in Bolivia’s salt flats, which are estimated to hold around 23 million metric tons of lithium. Study author and mining company Lithium Americas VP Tom Benson tells Mining.com that the Thacker Pass deposits are “right at the surface of the Earth, which makes it “one of the least impactful mines ever to be built.’” Benson’s company website says the Thacker Pass mine would go down a maximum of 122 meters; Midwest Lithium is drilling down into the rock near Mount Rushmore about 260 meters.
Of course, if the lithium skips South Dakota, we won’t miss out on much tax revenue, since the Legislature couldn’t figure out how to tax lithium mining last Session.