EXCEPTIONAL ROCKCHIP AND SOIL RESULTS RECEIVED FOR ANTIMONY RIDGE, HORSE HEAVEN GOLD-ANTIMONYSILVER-TUNGSTEN PROJECT, IDAHO, USA
Exceptional Rock Chip and Soil Results from Antimony Ridge
Adelaide, Sep 15, 2025 AEST (ABN Newswire) - Resolution Minerals Ltd (
ASX:RML) (NC3:FRA) (RLMLF:OTCMKTS) is pleased to report exceptional rockchip and soil sampling results from the Antimony Ridge Target ("Antimony Ridge") within the Horse Heaven Gold-Antimony-Tungsten Project in Idaho USA ("Horse Heaven") (Figure 1*).
Very high-grade antimony (Sb) and silver (Ag) and strong gold (Au) assay results received as part of recently completed surface rockchip and soil sampling program at Antimony Ridge.
Peak rockchip results include grab sample 730253: 49.8% Sb, 1,420 g/t Ag and 3.12 g/t Au (the highest grades recorded at Horse Heaven to date) and grab sample 730255: 10.35% Sb, 68.5 g/t Ag and 4.43 g/t Au.
Peak soil results include Sample 931406: 0.5% Sb; and Sample 931242: 0.9g/t Au and 68g/t Ag.
These results support historical sampling which had delineated broad antimonygold-silver mineralisation over significant widths at Antimony Ridge.
The Horse Heaven Project is directly adjacent to the Perpetua Resources' large Stibnite Gold Project.
Highlights
- Rock samples comprising massive stibnite (an antimony sulphide mineral) were collected from a historical antimony mine located at the Antimony Ridge Target as part of a comprehensive historical data verification program. Subsequent assay results have returned grades of 49.8% Sb, 1,420g/t Ag and 3.12g/t Au.
- Soil sampling at Antimony Ridge helps define a NE-SW trending zone of Sb-Ag-Au mineralisation 1,000m x 700m, with assay results up to 0.5% Sb, 0.9g/t Au and 68g/t Ag from an area southwest of prior sampling.
- The Antimony Ridge mineralised footprint is materially larger than previously known as a result of the soil Sb-Ag-Au results.
- Possible additional parallel Sb-Ag-Au zones of mineralisation are also indicated by the soil Sb-Ag-Au results.
- Prior trench rockchip results, up to 5.9g/t Au, 19% Sb and 367g/t Ag are located centrally within this expanded NE-SW trending zone of Sb-Ag-Au mineralisation.
- Sb-Au-Ag mineralisation is exposed at surface along 500 metres of historical trenching where production of high-grade Antimony from small open pits was recorded during the periods of WWII, and into the early 1950s.
- Historical drilling at Antimony Ridge is reported to have intersected significant Au mineralisation, including 1.0 g/t Au over 36.8m in GGR-12 and 0.79 g/t Au over 19.8m in GGR-16, but drillholes were not assayed for Sb and only partially assayed for Ag.
- Follow-up work will include further rockchip sampling, mapping and bulk sampling at Antimony Ridge, that will help refine drill targets for a later planned drill program.
- Resolution is collecting representative samples of antimony from stibnite-silica vein exposures at Antimony Ridge to conduct preliminary metallurgical test work.
- Resolution is pleased to report that it has now completed 6 core drill holes at the ongoing Phase 1 drill program at the Golden Gate target, totalling 4,967 feet (1,513 meters) of drilling. The Company is currently drilling its 7th hole, and the program is proceeding at a good pace. Further, the first two holes have been logged, split and submitted to ALS for assaying. Initial results will be released when available.
The Company is conducting an extensive surface sampling program at the Antimony Ridge and Golden Gate targets. The intention is to define a possible Sb-Au-Ag JORC compliant Exploration Target. Intrinsic in this program is the verification of past exploration results and past production data from both target areas.
The current results greatly enhance the prospectivity of Antimony Ridge, illustrating the potential of very high-grade mineralisation over an expanded mineralised footprint. It has become a large and consistently mineralised area of Sb, Au and Ag, which expands the target area within the Horse Heaven Antimony-Tungsten-Gold Project located in Idaho, U.S. (Figure 1*).
Rockchip Sampling Program at Antimony Ridge
A significant rockchip sampling program was conducted across the Horse Heaven Project area. As part of this program, seven samples were taken from Antimony Ridge (Appendix A*).
Two rockchip samples, 730253 and 730255, were taken from a pile of ore material, found adjacent to an abandoned and overgrown mine (believed operational circa 1950s-1980s). Visual mineralisation is the antimony sulphide mineral, stibnite. The stibnite is described as massive, and the estimated percentage of stibnite of the rock specimens is between 75% to 90%.
Subsequent assay results of these two samples report exceptionally high grades of Sb and Ag, and strong grades of gold.
Grab sample 730253: 49.8% Sb and 1,420 g/t Ag and 3.12 g/t Au; and Grab sample 730255: 10.35% Sb, 68.5 g/t Ag and 4.43 g/t Au.
The purpose of sampling stibnite ore material is to obtain an understanding of grades of antimony mineralisation considered historically to be of economic importance. This is important for the integration of historical production data into a possible future JORC-compliant Exploration Target and/or Resource figure. Knowledge of the Antimony Ridge ore material (grade and characteristics) is also extremely useful in interpreting current and future exploration results.
Soil Sampling Program at Antimony Ridge
A soil sampling program ("Soil Program") conducted across Antimony Ridge was recently completed. The Soil Program comprised 210 samples collected on a NE-SW orientated grid with a 100m line spacing and a 25m sample spacing (Appendix B*). Assay results for Au, Ag, Sb and tungsten (W) are presented in Appendix C*.
Sb, Au and Ag heat maps show geochemical anomalies representing a series of mineralised NESW zones that parallel/sub-parallel the main trend of mineralised en echelon structures that traverse the Antimony Ridge Target area (Figures 3A* and 3B*, and Appendix B*). These repeated (or "stacked") NE-SW Sb-Ag-Au mineralised zones form a broad corridor of mineralisation approximately 1,000m long and 700m wide. Several of these mineralised zones appear to be fault offset (Appendix B*).
Importantly, this broad mineralised corridor (as defined by soil geochemistry) represents a materially larger mineralised footprint than previously known. Furthermore, this broad mineralised corridor is open-ended along strike in both directions and possible additional parallel NE-SW zones also possible.
Past Channel Rockchip Exploration at Antimony Ridge
The soil results detailed in this announcement are put into context of the previous exploration results of Antimony Ridge.
Past trench rockchip sampling programs from the Lower Trench, Bowl Cut, Ridgetop and East Trench at Antimony Ridge identify significant Sb, Ag and Au mineralisation (RML ASX release "Agreement to Acquire Major US Antimony Project and Placement" on 11 June 2025) (Table 2*, Figures 3* and 4*) at Antimony Ridge. Of the sixty-one rockchip samples (channel and grab), collected in the 2022-23 program, more than 60% returned results greater than 1g/t Au, with peak values of 5.9g/t Au, 19% Sb and 367g/t Ag.
As reported in the 11 June 2025 ASX announcement, mineralisation is hosted in veins and narrow breccias within an altered granodiorite which trend NE-SW.
The recently generated NE-SW trending soil Sb-Ag-Au anomalies, described above, are entirely consistent with the spatial configuration of known Sb-Ag-Au mineralisation exposed in the Lower Trench, Bowl Cut, Ridgetop and East Trench. The six soil anomalies are parallel to veins and breccias of the trenches. This strongly indicates the presence of additional mineralised veins and breccias beyond those exposed in trenches and past mine workings. It is concluded that a much larger system of mineralised veins and breccias are inferred by the soil anomalism.
Significant past (and previously reported) rockchip channel samples from Antimony Ridge include:
Rockchip sample 329003 with 3.68g/t gold, 303g/t silver and 2.72% antimony over 4m.
Rockchip sample 329014 with 1.33g/t gold, 367g/t silver and 13.75% antimony over 1m.
Rockchip sample 329015 with 4.65g/t gold, 70.5g/t silver and 19.15% antimony over 1m.
Rockchip sample 329085 with 3.21g/t gold, 178g/t silver and 0.37% antimony over 3m.
Rockchip sample 329089 with 5.99g/t gold, 246g/t silver and 0.71% antimony over 1m.
RML's CEO of U.S. Operations, Craig Lindsay, commented:
"We are very encouraged with the recent sampling program results from Antimony Ridge, which indicate that the mineralised target is larger than initially thought. As we expand outwards from the immediate area of the historic workings, we look to expand the target even further. Indeed, Horse Heaven is revealing itself to be a much larger opportunity as we conduct modern multi-disciplined exploration across the project area. It's potential as a very significant antimony, gold, silver and tungsten project is crystalising."
RML's Senior Strategic Advisor, Steve Promnitz, commented:
"Not all Antimony is equal. High grades around 50% Sb are truly rare - and usually reflect crystalline antimony, potentially available for direct shipping ore as an oxide. This is because high grade antimony requires limited processing - and is therefore sought after."
Expanded Mineralised Target in Soil Sampling - Antimony Ridge Target
The Antimony Ridge soil sample program results for antimony, gold and silver has significantly expanded the target area to over 1,000m x 700m, open-ended in all directions, within the Horse Heaven Gold-Antimony-Tungsten Project (Figure 1, Appendix B*).
Soil geochemistry now delineates mineralisation beyond past producing antimony workings, particularly NE of the historic Antimony Ridge trench. This strongly supports the increased prospectivity and mineralised footprint of Antimony Ridge and, more broadly, the Project's potential to host significant antimony-gold-silver-tungsten mineralisation.
Bulk Sample Testing of Antimony Workings - Antimony Ridge Target - Horse Heaven
The Company is currently collecting representative samples of stibnite-silica vein mineralisation from exposures at Antimony Ridge. These samples will be used to conduct initial metallurgical test work and mineralisation characterisation studies.
Next Steps
The encouraging soil sampling and mapping at Antimony Ridge will lead to further rockchip sampling, planned bulk sampling and a drill program.
A thorough analysis of the rockchip results for Antimony Ridge and Golden Gate is ongoing. When the program is fully completed and assay results available, results will be released. The Company is currently conducting a project-wide stream sediment program. When the program is completed and assay results available, results will be released.
In addition to the permitted and ongoing drilling at the Golden Gate target area, Resolution plans to apply for a permit to undertake Phase 1 drilling at Antimony Ridge.
About Rivere Minerals
Riviere Minerals Pty Ltd ("Riviere") is a resource consultancy specialising in project evaluation and portfolio management. Its principal geologist and sole director, Mr Ross Brown, has nearly 40 years of experience in mineral exploration worldwide. Through Riviere, Mr Brown also provides assistance in exploration planning, execution and ASX reporting.
*To view tables and figures, please visit:
https://abnnewswire.net/lnk/4X8FZVEW
About Resolution Minerals Ltd
Resolution Minerals Ltd (ASX:RML) (OTCMKTS:RLMLF) (FRA:NC3) is a mineral exploration company engaged in the acquisition, exploration and development of precious and battery metals - such as antimony, gold, copper, and uranium.
Resolution Minerals Ltd Listed on the ASX in 2017 and has a broad portfolio of assets, such as the Drake East Antimony-Gold Project in north-eastern NSW and George Project prospective for silica sand and uranium.
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