Resolution Minerals picks up project next to biggest antimony play in US

• RML to acquire Horse Heaven Antimony Gold Tungsten project in Idaho, US
• Project next to Stibnite project, largest known antimony resource in US
• Drill-ready targets for maiden program this year

Special Report: Resolution Minerals is acquiring an antimony, gold & tungsten project in Idaho – next to the largest known antimony resource in the USA.

Antimony, tungsten and gold are all trading at record highs as China tightens its grip on critical minerals exports, with antimony hitting US$59,800/t last month.

Plus, antimony is classified as a critical mineral by the USA, Australia, European Union, Japan, China, Canada, UK and South Korea.

The new Horse Heaven project acquisition shares its eastern boundary with A$2bn market cap Perpetua Resources (PPTA.NAS) and its Stibnite gold-antimony project in the historical Stibnite Mining District of Valley County, central Idaho.

Stibnite hosts a 4.8Moz gold reserve, and a 148Mlb antimony reserve and once reopened, will be the only domestically mined source of antimony in the US, supplying around 35% of the country’s demand.

Horse Heaven has strong gold, antimony and silver mineralisation in two prospects – the Antimony Ridge Fault Zone (ARFZ) and the Golden Gate Fault Zone (GGFZ) – and includes past-producing antimony and tungsten mines.

Past rock chip results include up to 5.99g/t gold, 367g/t silver and 19.15% antimony, with past drilling returning up to 1.459g/t gold.

Resolution Minerals (ASX:RML) said the brownfields project was a transformational acquisition, with these highly encouraging past results indicating large tonnage mining potential.

Its entry into US critical minerals development comes at a terrific time, with the market attributing huge premiums to companies operating in the space thanks to the supportive pro-mining policies of new President Donald Trump.

The dramatic regulatory shift has seen ASX-listed US explorers race to prominence, with Dateline Resources (ASX:DTR) running from a market cap of less than $10m to over $400m in the past two months thanks to its Colosseum gold mine and rare earths project in California.

Trigg Minerals (ASX:TMG) shares have almost tripled in value in the past month since moving into the US antimony space, spurred on by the Trump Government ‘drill, baby, drill agenda’, while nanocap Locksley Resources (ASX:LKY) has run 5 times higher over the past month thanks to its Mojave project near the Mountain Pass rare earths mine.

Could Resolution be the next ASX small-cap to see those tailwinds with its antimony deal?

Location of Perpetua Resources’ Stibnite gold antimony project. Source: RML.

Fast-tracking and defence funding opportunities

The company said the Horse Heaven project also complemented its recently acquired Australian gold-antimony-copper projects – Drake East antimony-gold project (NSW), Neardie antimony project (Qld) and Spur South gold-copper project (NSW) – to create a dynamic portfolio highly leveraged for gold and antimony.

Not to mention, the project is eligible for fast-tracking under FAST-41, just like Stibnite which was fast-tracked for approval in April, and on May 19, 2025, obtained final approval to be re-opened.

The company is also eyeing potential US Defense Department funding opportunities, with the department recently awarding Perpetua up to US$74 million in grants to advance Stibnite – highlighting antimony’s status as a critical defense metal.

“The acquisition of the Horse Heaven project is a company transforming event for RML,” executive director Aharon Zaetz said.

“As many governments around the world look to onshore their supply of critical minerals, such as antimony, we have secured a commanding ground position with known antimony occurrences and next to what will soon be the largest antimony producer in the USA.

“This new flagship project complements our current gold and antimony projects in Australia, and we believe it positions RML strongly to capitalise on the growing global demand for critical minerals.”

RML is expected to begin drilling the promising antimony prospects at Horse Heaven in the near-term.

This article was developed in collaboration with Resolution Minerals, a Stockhead advertiser at the time of publishing.

 This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.