American Rare Earths’ Cowboy State mine: resource upgrade and PFS lens for engineers

American Rare Earths is one of only a handful of rare earths and rare earth oxides names in our recent mining coverage, which suggests Cowboy State in Wyoming could become a reference project for US-based critical minerals outside the more commonly reported Canadian and Australian hubs.
The combination of a 547.5 Mt resource at Cowboy State and state-backed non‑dilutive funding in Wyoming positions ARR differently from many junior rare earths developers in our database, which more often rely on equity raises or strategic offtake to fund early drilling and scoping work.
With ARR targeting antimony capacity by 2028 alongside rare earth oxides, the company is aligning two US‑listed critical minerals that feature far less frequently than copper or gold in our mining corpus, potentially making Halleck Creek and any South Australia processing facility more attractive to downstream buyers seeking diversified non‑Chinese supply.

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