Resolution Minerals Ltd (ASX:RML, OTC:RLMLF) has agreed to acquire the Horse Heaven Project, a highly prospective antimony-gold-silver-tungsten project in the historic Stibnite Mining District in central Idaho’s Valley County – a prime location adjacent to one of the largest gold-antimony projects in the US.
This deal is part of company’s expansion of its portfolio into the critical minerals space, with a particular focus on antimony and tungsten, both of which have seen prices surge amid global supply concerns.
Strategic location and project highlights
The Horse Heaven Project shares its eastern boundary with Perpetua Resources’ Stibnite Gold-Antimony Project, giving it strategic value in the rapidly growing US critical minerals market. The project hosts two major fault zones, the Antimony Ridge Fault Zone (ARFZ) and the Golden Gate Fault Zone (GGFZ), both of which are known to contain high-grade mineralisation of gold, antimony, silver, and tungsten.
Location plan of the Horse Heaven Project.
Preliminary drilling results and rock chip samples from Horse Heaven have returned significant results. Notably, rock chip sample 329003 from Antimony Ridge assayed 3.68 grams per tonne (g/t) gold, 303g/t silver, and 2.72% antimony over a 4-metre interval, underscoring the project’s potential.
Past drilling has also highlighted large tonnage potential, with drillhole 87-GGR-31 intersecting 85.34m at 0.937g/t gold, including 38.10m at 1.459g/t gold. The project also benefits from a history of production, including artisanal gold and past tungsten production at Golden Gate Hill between the 1950s and 1980s, adding to its near-term exploration and development potential.
Project plan showing the geology of the Horse Head Project area. The two main prospect areas, within the project area, are highlighted: The Golden Gate Hill Mine located in the GGFZ, and Antimony Ridge, located in the ARFZ.
Resolution Minerals plans to begin drilling at Horse Heaven in 2025, with targets set for both the ARFZ and GGFZ.
Exploration potential and resource estimates
In addition to the drill-ready targets at Horse Heaven, historical estimates include 216,000 ounces of gold at Golden Gate Hill and 70,000 ounces at Antimony Hill. While these figures are not compliant with the JORC Code and should be treated with caution, they provide a useful reference for the potential of the project.
Further exploration will aim to confirm and expand these resources, with a particular focus on gold, antimony and tungsten mineralisation.
The project covers 5,644 hectares and includes a combination of 689 mining claims and 10 lode mining claims. Notably, Horse Heaven sits within a historically prolific mining region, which has seen multiple phases of exploration and production since the late 1800s, with more recent work by TSX-V-listed Stallion Uranium Corp. further enhancing the project's appeal.
Project plan showing the configuration of 699 U.S. Federal lode mining claims (covering 5,644 hectares). The project comprises 685 mining claims and ten lode mining claims referred as the Oberbillig Group (purple reference numbers).
A critical minerals play in a growing market
The acquisition of the Horse Heaven Project strategically positions Resolution Minerals within the US critical minerals sector, particularly for antimony and tungsten, both of which are critical to industries such as defence, aerospace, and energy. The US government has increasingly focused on securing domestic supplies of these materials, as evidenced by the reopening of the nearby Stibnite Gold Mine, which is set to become the only domestic source of antimony once operational.
With prices for antimony and tungsten at record highs due to supply chain issues, Resolution Minerals is looking to capitalise on this growing demand. Executive director Aharon Zaetz highlighted the acquisition's transformative potential for the company.
“As many governments around the world look to onshore their supply of critical minerals, such as antimony and tungsten, we have secured a commanding ground position with known antimony occurrences and net to what is likely to become the largest antimony producer in the USA,” he said.
“RML’s entry into US critical minerals comes at a terrific time, with the market attributing huge premiums to ASX-listed companies operating in the space over the last eight weeks, such as Dateline Resources, Trigg Minerals and Locksley Resources, which have all seen significant re-ratings in recent weeks, thanks to the supportive pro-mining policies of new President Donald Trump.”
Next steps and funding
With the acquisition secured, Resolution Minerals is moving forward with a comprehensive exploration program at Horse Heaven. The company has already completed initial geophysical surveys and is planning further soil sampling and metallurgical testing to better define the mineralisation across the project.
The planned exploration is aimed at advancing both the ARFZ and GGFZ targets, and a significant drill program is expected to follow.
To fund the Horse Heaven acquisition and upcoming exploration activities, Resolution Minerals has raised $1.9 million through a placement, which will also support the company’s other projects. This funding will allow the company to pay the cash consideration for the Horse Heaven Project, while also advancing its broader exploration initiatives as it works to expand its footprint in the critical minerals sector.