Resolution Minerals Reports Up to 48.7% Antimony and 890 g/t Silver at Idaho Project

Exceptional Surface Sampling Results

Resolution Minerals Limited (ASX – RML) has delivered a significant update from its Horse Heaven Project in Idaho, USA, reporting exceptional high-grade antimony, silver, and gold assay results from rock samples collected at the historic Antimony Ridge Mine. The standout results include antimony grades reaching as high as 48.7% and silver concentrations up to 890 grams per tonne, confirming the presence of a robust polymetallic system at surface.

The samples, collected in October 2025, were taken from within the old open pits and trenches of the Antimony Ridge Mine, a site with a history of production. These grab samples, averaging 3.6 kilograms each, returned consistently high grades, with an average antimony content of 39.2% and silver averaging 430 g/t. Gold was also present in meaningful quantities, enhancing the project's overall value proposition.

Strategic Location and Project Significance

Antimony Ridge lies adjacent to Perpetua Resources’ Stibnite Gold Project, a recently permitted and large-scale antimony-gold development. This proximity places Resolution’s project within a strategically critical US jurisdiction, especially as antimony supply has become a national priority due to its importance in defence, energy storage, and other critical technologies.

Craig Lindsay, CEO of Resolution’s US operations, emphasised the rarity of such high-grade antimony mineralisation exposed at surface and the strategic timing of the discovery. He highlighted that the consistent association with silver and gold further enhances the project's appeal, positioning Horse Heaven as a potentially vital asset in the US critical minerals supply chain.

Advancing Towards Development

Resolution has collected approximately 100 kilograms of representative stibnite-silica vein material for metallurgical testing, which is currently underway at facilities in Canada and Australia. These tests aim to characterise the mineralisation and identify viable commercial processing pathways.

Meanwhile, permitting efforts are progressing to enable drilling and bulk sampling within the historic mine area. The company plans to commence an initial drilling program once permits are secured, aiming to delineate the extent of the high-grade mineralisation and de-risk the project further.

Additionally, assay results from the 2025 drilling campaign at the nearby Golden Gate Target are pending, which could provide further insights into the broader Horse Heaven Project’s potential.

Outlook and Market Context

With the US government increasingly focused on securing domestic sources of critical minerals, Resolution’s Antimony Ridge project is well positioned to attract attention. The combination of exceptional grades, strategic location, and advancing technical work could unlock significant value for shareholders and contribute to strengthening the US antimony supply chain.

However, as with all early-stage exploration projects, key uncertainties remain, including the outcomes of metallurgical testing, permitting approvals, and the results of forthcoming drilling programs. These factors will be critical in determining the project's commercial viability and timeline to development.