A truly incredible intercept of 189.2m at 1.30 g/t Au from 34m, including 12.9m at 2.32 g/t Au from 94.4m and 70.8m at 2.24 g/t Au from 128.8m, at Resolution Minerals’ (ASX: RML) flagship Horse Heaven project in Idaho has demonstrated both grades and continuity of mineralisation that are excitingly similar it’s neighbouring 6Moz Stibnite mine – which is just 5km away and owned by US$3 billion market cap Perpetua Resources’ (NASDAQ: PPTA).
This first assay from RML’s 10-hole, 2,743m diamond drilling campaign is from the Golden Gate Prospect, and it ended in mineralisation at a depth of 223m. This is significantly further than historical drilling that had only tested to around 150m, and also saw grades increase as the drill core went through the oxide and transition layers, and into the sulphide zones. Identical looking sulphide cores have been seen in the subsequent two drill holes, of which assays are imminently due.
Stibnite’s main orebody – the 2.7Moz Yellow Pine pit – is contained across a strike of 427m, a width between 50–198m, and with down-dip continuity to a depth of 366m. Golden Gate has a 3.5km strike, mineralisation that now extends to at least 223m, and an ongoing drill program that is increasing the width – outline clear potential for a Stibnite scale deposit.
RML just raised $27 million through Oakley Capital Partners and Roth Capital Partners, which included investments from John Hancock’s Family Office, Astrotricha Capital SEZC, Tribeca Investment Partners and Next Investors. JP Morgan just picked PPTA as its first US National Security Fund investment, with a US$75 million equity injection, which was quickly followed by US$180 million from Agnico Eagle (TO: AEM).
RML’s advanced project is shaping up to be both an analogue and a major geological extension of Stibnite’s monster 4.8Moz at 1.43g/t Au and 0.06% Sb reserve – and today’s assays are in the same section of the project that has previously hit 150m at 0.940 g/t Au from surface, including 88m at 1.26g/t Au from 64m, as well as 85m at 0.937g/t Au from surface, including 38.18m at 1.46g/t Au from 50.29m. There is a clear trend of continuity of mineralisation, and grades increasing at depth – which is exactly what we want to see at this project.
As RML continues planning its 15,000m drilling campaign for 2026, which will test numerous geophysical anomalies that correlate to extraordinary rock chips up to 7g/t Au and widespread high-grade trench samples – there will be many more assays from previously untouched depths in various parts of the project over the next few weeks. Horse Heaven is an Intrusion-Related Gold System just like Stibnite, which itself has previously produced 980koz of gold, 40kt of antimony and 6kt of tungsten – and has just broken ground to begin developing a mine that will process over 460kozpa in its first four years.
Golden Gate has a historical resource of 216koz at 0.93g/t Au, but has also produced over 2,000t of tungsten oxide that graded between 1.5-2% W – which is especially interesting when considering the scheelite that was repeatedly seen throughout today’s drill core.
The other main prospect at Horse Heaven is Antimony Ridge, which has historical production of over 1,000t of antimony that graded an astounding 45% Sb, and a recent raft of insanely high-grade rock chips up to 49.8% Sb, 1,420 g/t Ag and 3.12 g/t Au, and grab samples up to 10.35% Sb, 68.5 g/t Ag and 4.43 g/t Au.
RML expects to be able to drill at Antimony Ridge soon, where it will target the highest grade areas to establish a resource that will be used as the base of its downstream antimony operation. The company recently engaged Kingston Process Metallurgy to run a variety of programs that will determine the best processing methods, and have appointed Tribeca as its corporate adviser to develop and promote its US critical minerals strategy.
While gold’s recent explosion to an all time high of US$4,380/oz was followed by a sudden retracement back towards US$4,000/oz, with relative volatility seen across the relevant explorers as a response – these prices are already insanely attractive to projects like Horse Heaven. The Stibnite mine had its definitive feasibility study done in 2020 at a gold price of just US$1,850/oz, which at the time was considered strong, and still came out with a US$1.864 billion NPV (albeit at a 5% discount rate). Increasing the gold price to US$2,350/oz takes the NPV to US$2.943 billion – and the current gold price would astronomically increase this figure.
Our cornerstone antimony pick Trigg Minerals (ASXL TMG) rose over 640% from our initial entry price, reaching a market cap of $280 million. RML’s valuation has fluctuated significantly recently, hitting a $270 million market cap before retracing to around $122 million – right as the first round of assays were due to arrive.
The environment for critical minerals in the US has materially improved over the past few weeks, after almost a year of China’s export bans culminated in a crescendo of sorts where the Australian and American Governments inked an US$8.5 billion deal to fund each other’s critical mineral projects. With a significant amount of capital to be deployed in the next 6 months, the likelihood of companies like RML and TMG, who have managed to get their hands on highly prospective projects with encouraging historical exploration and production, receiving funding is sky high.
A cross section of today’s intercept can be seen below:
Source: RML
Gigantic American IRGS’ Portray RML’s Potential
The easily extractable nature of the Stibnite deposit and its aggressive development plan has left the market with no choice but to drive up PPTA’s valuation to record but not necessarily unreasonable levels, and RML’s Horse Heaven could play a critical role in fully utilising the enormous infrastructure being built next door – which will only be at full capacity for the first few years.
From the 4.8Moz at 1.43g/t of mineral reserves are Stibnite, more than a third of it will be mined in the first four years at an astonishing annual rate of 463koz. Even more impressive is the grade, which will average 2.2g/t during this time – resulting in 7.3Mtpa mill churning out ounces at a globally competitive AISC of a mere US$438/oz.
Taking an extreme case of low-grade, large scale open-pit mining, such as Kinross Gold Corp (NYSE: KGC)’s 12Moz Fort Knox, demonstrates what is possible at a gigantic IRGS in the USA. The mine has a 16Mtpa mill that is operating significantly under capacity – averaging 55% in 2022, 50.16% in 2023 only 40% in 2024 – while receiving head grades between 0.7-0.8g/t – and still produces gold at US$1,205/oz. The robust infrastructure but lack of onsite ore has seen Kinross actively engaging in M&A to extend the life of Fort Knox, with the company going as far as mining and transporting the 4g/t Manh Choh deposit that is a whopping 400km away.
All of Stibnite’s ore reserves will be exhausted after 15 years, with the most valuable component being completely mined out after 4. PPTA needs to have a firm foothold in anything worthwhile in its vicinity to have strong prospects of increasing mine life and maintaining grades – and RML is now the perfect candidate. Below is a chart that shows the front-loaded nature of Stibnite’s best years, followed mostly by declining grades and exhaustion of reserves:
Source: PPTA
Stibnite has attracted exciting levels of funding that RML will hopefully continue to gain access to. PPTA recently ruled off a US$425 million equity financing package, which included US$100 million from legendary hedge fund manager John Paulson’s private family office. This is on top of the almost US$2 billion in debt that PPTA is on track to receive from EXIM, which will cover most of the development costs.
PPTA has also received US$80 million of government funding over the years, much of which has been towards permitting and feasibility studies, but also to assess the suitability of antimony production. US$6.9 million of it came from the US Army to demonstrate the feasibility of using material sourced from Stibnite to produce military-specification antimony trisulfide.
Antimony Industry Needs Multiple US Producers
The US-Australia (Trump-Albanese) deal has the potential to further anger China, and there is no sign of reprieve for the antimony market – the supply constraints of which have seen historically elevated price levels since 2021 – prior to the Ukraine and Palestine wars as well solar panel demand. This was when China first really started withholding trisulfide from the US, but it only induced a price increase to the US$11,000-US$13,000/t mark.
While antimony’s 500% increase in just over a year to as high as US$62,000/t has been triggered by the panic of a total ban, and Western consumers being forced to buy it from anyone outside of China, Russia and Tajikistan – it has also exposed the fragility of the entire industry that posed major risks to US national security and has proved to be a pain point that can be pressed.
Military grade antimony trisulfide has always fetched a significantly higher price than the actual value of its contained antimony, and there have been instances of this margin being more than double. The USA’s need for this product that is critical to more than 300 types of munitions is more urgent now than ever.
The chart below depicts the recent price action of antimony in its different forms and locations, which include concentrate, ingot and trioxide, from Rotterdam, Baltimore and China. The DoD funded years of testing with Stibnite’s ore and eventually approved it as material that can be processed into military grade trisulfide – and RML’s project contains much of the same material:
Source: Blue Ocean Equities
RML recently expanded the tenement package through the acquisition of an additional 30 federal lode mining claims, which takes the project size to 59km2 – right next to PPTA. As the drilling continues at Golden Gate, RML is also seeking permits to drill at Antimony Ridge – making for an upcoming period of extremely exciting news flow.
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Disclaimer: This article is for informational and marketing purposes only, and does not constitute financial advice or a recommendation to invest. All opinions expressed are our own. We may receive fees or other forms of compensation in connection with the publication of this content, and may own shares in any of the mentioned companies. Please do your own research and seek professional advice before making any investment decisions.