PROJECT SNAPSHOT
The Horse Heaven Antimony-Gold-Tungsten Project is well-situated in Valley County, Idaho USA, sharing its eastern boundary with Nasdaq-listed Antimony giant Perpetua Resources’ (~A$2 billion market cap) Stibnite Gold Project. Stibnite hosts a 4.8M ounce Gold reserve and a significant endowment of Antimony and tungsten.
The Horse Heaven Project comprises 699 federal lode mining claims covering over 5,644 hectares and is home to a number of past-producing Antimony, Tungsten and gold mines. The project has several high-priority target areas, including the Golden Gate & Antimony Ridge prospects. Shallow historical drilling has confirmed mineralisation from surface.
The project is close to the town of Cascade, Idaho, and important infrastructure, which is being upgraded to support the development of the Stibnite Mine.
Location of the Horse Heaven Project in the USA
Location of the Horse Heaven Project and the nearby Stibnite Gold-Antimony Mine
Horse Heaven shares its eastern boundary with Perpetua Resources’ Stibnite Gold Project. Due to its high grade and low strip ratio, Stibnite is set to become one of the largest high-grade, low-cost gold mines in the USA and the only domestic source of antimony. Stibnite boasts 6M oz of Measured & Indicated gold reserves, with antimony and tungsten being “by-products.”
It also has a solid history of gold antimony production, having yielded over 980,000 oz of gold, 13.5M pounds of tungsten, and 88M pounds of antimony at Stibnite during WWII and the Korean War, accounting for 90% of total US antimony production at the time.
The Golden Gate Prospect has a historical, non-JORC code compliant gold resource of 216,000 ounces of gold in 7,256,800 tons of material at a grade of 0.93g/t at Golden Gate Hill, and gold resource of 70,000 ounces of gold in 3,174,850 tons of material at a grade of 0.69g/t at Antimony Hill.
From the 1950s up to 1980’s approximately 8000 tons of tungsten was mined at the prospect.
High-grade Antimony was produced from small open pits at the Antimony Ridge Prospect during the periods of World War I, World War II, and into the early 1950s, confirming significant potential to host Antimony deposits.
Historical trenching has also identified a 500m Antimony-Gold-silver mineralisation trend at the prospect.
“For national security, domestic antimony production must be maximized”
– A. Gustafson, The Heritage Foundation
The Horse Heaven project offers a compelling pathway to develop a significant antimony resource and address both upstream and downstream antimony supply challenges at a time when this critical mineral is in increasingly high demand. Antimony is crucial for defence, electronics, flame-retardant materials, and renewable energy technologies, yet the United States currently depends entirely on imports. Creating a secure domestic supply is now a stated priority of the U.S. Government.
The project is fully permitted for drilling, with an upgraded resource expected in 2026. Historical concentrate production has already occurred near the site, and recent samples have shown exceptionally high grades of up to 50% antimony. These findings confirm the strong geological potential and the opportunity to further explore and develop the resource.
Importantly, initial discussions around offtake and processing are already underway, positioning the project for commercial opportunities. The project is de-risked by its proximity to the federally supported Stibnite Gold-Antimony Project in Idaho, where the U.S. Department of Defense has already provided strategic backing.
Conceptual Processing facility
