The US-based company is looking to raise A$13-17 million at 25c per share to list in Australia and explore what is widely considered the one of the most prospective areas in the US for hard rock lithium, targeting areas that hosted lithium production in decades past, where some of the world's largest spodumene crystals were located.
Work has already mapped outcrops, drilling permits have been applied for, and the explorer promises a fast-paced exploration campaign across multiple brownfields targets that could support delivery of a definitive feasibility study by the end of 2025.
Historically significant tenure
The company has staked or optioned around 93sq.km in the Black Hills, including the previously worked Ingersoll and Mateen lithium mines and the Old Mike tantalum-mica open pit.
The Black Hills was once one of the world's main producers of hard rock ore, with at least 70,000 tonnes at 6% lithium reportedly recovered before demand fell in the 1950s, and the district slipped into obscurity.
With US domestic demand for lithium rising the district has become an obvious place to focus.
ASX-listed Iris Metals and Patriot Lithium are already active, and Midwest hopes to join then.
Midwest says there are some 24,000 intrusive pegmatite bodies identified by the US Geological Survey, some of which are known to be mineralised, particularly in the south around the Harney Peak Granite that is believed to be the source of the lithium-caesium-tantalum dykes.
Estimates suggest 2-5% could contain spodumene.
Old workings a focus
The company will initially revisit the Ingersoll and Mateen mines, where grab sample assays have confirmed areas of interest, before moving to other areas such as Soda Spar that previously produced feldspar and beryl, and Scott's Rose project that is immediately adjacent to Iris' holdings.
Mateen is the initial focus given it was one of the largest historical spodumene producers, reportedly producing 34,000t at 1.2% lithium. Ingersoll, the second priority, produced mainly lepidolite with just 80t of spodumene.
Midwest previously secured pre-IPO funding from ASX-listed juniors such as Arizona Lithium and Resolution Minerals.
Veteran team
The board includes executive chair Rodrigo Pasqua, previously with Sandfire Resources and Evolution Mining, and technical director Barry Junor, who oversees mine geology for Allkem.
Joining them as non-executive directors are company secretary Matthew Foy and geologist James Clark, who has advised large mining houses and jurisdictions on the development of battery raw materials strategies for GM, Tesla, Ford, Rio Tinto, US Department of State, Ontario and Quebec.
CFO Peter Ramsay is ex-Anglo American and Xstrata, while COO Michael Schlumpberger is a mining engineer who was previously CEO at American Pacific Borates.
Midwest hopes to list later in October.
