Successfully Upgraded Tungsten to Concentrates of 52% WO3 – Produced from Golden Gate Stockpiles

GRAVITY PROCESS SUCCESSFULLY PRODUCED A 19x TUNGSTEN UPGRADE TO STOCKPILED ORE WITH FURTHER TESTING UNDERWAY

April 28, 2026 (Source) — HIGHLIGHTS

• Tungsten Concentrate Produced: Tungsten concentrates of 52.3% tungsten trioxide (WO3) were produced from preliminary gravity separation test work on large samples from tungsten bearing stockpiles at the Johnson Creek mill site, sourced from the historical mining at the Golden Gate Tungsten mine, within Resolution’s Horse Heaven Antimony-Tungsten-Gold Project in Idaho USA.
• Significant Tungsten Upgrade Achieved in Test Work: Stockpiled tungsten bearing ore is clearly amenable to simple gravity flotation processing in preliminary test work, as indicated by a significant upgrade, by a factor of 19 (19 times), relative to the stockpile composite sample tungsten grades 1.85 wt% WO3, present predominantly as scheelite.
• Scoping Tests Completed: Heavy liquid separation (HLS) scoping tests have been completed achieving up to 75.5% recovery grading 52.3 wt% WO3, with an upgrade ratio of 19.
• Mineral Processing Test Work Progressing: Further testing of concentrates is underway with a larger sample (50kg) being prepared for concentration via shaker table and final product results will be released in the coming weeks.
• Encouraging Results: Although the Heavy Liquid Separation (HLS) is preliminary, the results are encouraging for the short-term processing of the historical tungsten stockpile via simple gravity methods.
• Other Concentrate Test Work: Test work is also advancing on options to concentrate the antimony ore and gold at IMO labs in Perth, Australia, with further results soon.
• Smelting and Refining Discussions Progressing: Discussions with tungsten smelting and refining companies are underway.
• The processing options for tungsten stockpiles forms part of Resolution’s broader Horse Heaven strategy, which includes recently acquired processing infrastructure and a major 2026 drilling program at Golden Gate starting in May targeting gold and tungsten.

Resolution Minerals Ltd (ASX: RML; OTCQB: RLMLF) (“Resolution” or the “Company”) is pleased to report that tungsten concentrates of 52.3% tungsten trioxide (WO3) have been produced from preliminary gravity separation test work on tungsten composite samples, assaying 1.85% WO3, from stockpiles at the Johnson Creek mill site, originally sourced from the historical mining at the Golden Gate Tungsten mine, by IMO labs in Perth Australia (Sample grade reported in ASX announcement 26 March 2026).

Heavy liquid separation (HLS) scoping tests have been completed on the tungsten composite samples, achieving up to 75.5% recovery grading 52.3wt% WO3, with an upgrade ratio of 19, relative to the stockpile composite sample tungsten grades of 1.85 wt% WO3.

Size-by-assay test work: Size by assay was undertaken to understand the effect of different particle sizes on the liberation of tungsten-bearing minerals from the other “gangue” material in the stockpiled ore. The sample was crushed to 100% of the material passing through a 3.35mm screen (P100 3.35mm), then screened at seven different sizes with each fraction being collected and assayed independently (Table 1). This size-by-assay approach identifies if the tungsten minerals present naturally concentrate within specific size ranges, ultimately allowing determination of the best concentration strategy.

Table 1: Tungsten Stockpiles composite sample was crushed to P100 3.35mm, screened at seven different screen sizes with each fraction assayed independently (size-by-assay) to determine deportment of tungsten during size reduction.

HLS Test Work: Heavy liquid separation (HLS) is a process which exploits the natural difference in density between minerals. Tungsten containing minerals like scheelite are relatively dense compared to quartz and clays that they are associated with. Selecting a liquor with a density slightly higher than those uneconomic (gangue) minerals like quartz provides a media whereby the tungsten minerals are dense enough to sink to the bottom of the liquid whilst the gangue minerals float to the surface – providing a crude indication of the performance of well-known gravity separation methods. With the exception of the -0.02mm fraction, each screened fraction was subject to HLS at SG 2.9 (Specific Gravity – measure of density), with “sinks” representing the tungsten concentrate and “floats” representing the gangue. The upgrade ratio is a ratio of the WO3 concentration of the HLS concentrate (“sinks”) relative to the corresponding WO3 concentration of each size fraction. The recovery indicates the amount (mass) of WO3 that reported to the HLS concentrate (“sinks”) relative to the corresponding WO3 mass of each size fraction.

At the finest grind size of smaller than 0.53mm to larger than 0.02mm (-0.053mm, +0.02mm), a grade of 52.3% WO3 was achieved with recovery of 75.5% (see Table 2). The results also indicate that the grade remained relatively consistent at ~35% WO3 below the sample size of 0.5mm, while recovery increased with a decrease in particle size (see Figure 1). The results indicate that decreasing particle size increases both grade and recovery.

Further Test Work Progressing: Test work is now underway on a larger sample (50kg), ground to <0.25mm based on the HLS test results – which will be subjected to concentration via shaker table.

Test work is also advancing on options to concentrate the antimony ore and gold-bearing samples at IMO labs in Perth, Australia, with results expected soon.

Dr. Adam Roper, Resolution’s In-house Senior Metallurgist, stated: “The initial results are encouraging for the short-term processing of the historical tungsten stockpiles via simple gravity methods. This is a great start and I’m looking forward to discussing the final results in the coming weeks, while discussions are underway with smelters and refiners.”

Composite Sample from Stockpiles: Assay results of a late-2025 sampling program of historical stockpiles at the Johnson Creek mill site, containing ore material from the historical Golden Gate Tungsten Mine, returned high-grade tungsten, material levels of gold and low levels of impurity elements (See ASX announcement 26 March 2026).

A mini-bulk-sample of 93.6kg comprising composite of six samples of stockpile material contained 1.85% WO3 and material levels of gold at 0.11g/t. Independent mineralogy study identifies scheelite as the predominant WO3 ore mineral, with low levels of impurities, including but not limited to arsenic (As): 97 ppm; molybdenum (Mo): below detection; and phosphorus (P): below detection. Quartz (>90%) was identified as the predominant gauge mineral (non-ore) with minor gauge minerals calcite (trace levels) and potassic-mica (trace levels). (See ASX announcement 26 March 2026).

Historical mining occurred at Golden Gate in the 1950’s and the 1970’s until 1980. During World War II, the local District, including the adjoining Stibnite mine (Perpetua Resources), is estimated to have produced more than 90% of the US Antimony and 50% of the US Tungsten (Source: Perpetua Resources Stibnite Feasibility Study, Jan 2021). Golden Gate Tungsten mine is located within Resolution’s Horse Heaven Antimony-Tungsten-Gold-Silver Project in Idaho, USA, and immediately adjacent to Perpetua Resources’ Stibnite Gold Project, a large, recently permitted Antimony-Gold project. This result follows the selection of Antimony Ridge for FAST-41 Transparency Coverage from the US Permitting Council, announced on 8 April 2026. Selection reflects the strategic importance of Antimony Ridge as a potential source of U.S. domestic antimony supply, a critical metal essential for defence, energy, and industrial applications.

Future Plans

Further tungsten concentrate test work is underway and final product results will be released in the coming weeks. Resolution is initiating a major Phase 2 drilling program in May 2026, at the Golden Gate Project, of up to 45,000 ft (13,700 metres) of diamond core drilling located within the Company’s larger Horse Heaven Antimony-Tungsten-Gold-Silver Project. The program is designed to define the scale of gold and tungsten mineralisation at Golden Gate and Golden Gate South and support progression toward a maiden Mineral Resource Estimate.

Authorised for release by the Board of Resolution Minerals Ltd.

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Forward Looking Statements

This announcement may contain forward-looking statements. These statements relate to the Company’s expectations, beliefs, intentions or strategies regarding the future. These statements can be identified by the use of words like “anticipate”, “believe”, “intend”, “estimate”, “expect”, “may”, “plan”, “project”, “will”, “should”, “seek” and similar words or expressions containing same. These forward-looking statements reflect the Company’s views and assumptions with respect to future events as of the date of this release and are subject to a variety of unpredictable risks, uncertainties, and other unknowns. Actual and future results and trends could differ materially from those set forth in such statements due to various factors, many of which are beyond our ability to control or predict. These include, but are not limited to, risks or uncertainties associated with the acquisition and divestment of projects, joint venture and other contractual risks, metal prices, exploration, development and operating risks, competition, production risks, sovereign risks, regulatory risks including environmental regulation and liability and potential title disputes, availability and terms of capital and general economic and business conditions.

Given these uncertainties, no one should place undue reliance on any forward-looking statements attributable to the Company, or any of its affiliates or persons acting on its behalf. Subject to any continuing obligations under applicable law, the Company disclaims any obligation or undertaking to disseminate any updates or revisions to any forward-looking statements in this announcement to reflect any change in expectations in relation to any forward-looking statements or any change in events, conditions or circumstances on which any such statement is based.

Competent Person’s Statement

The information in this report that relates to exploration results, is based on and fairly represents information reviewed and compiled by Mr Ross Brown BSc (Hons), M AusIMM, Principal Geologist/director of exploration consulting firm, Riviere Minerals Pty. Ltd, who is a Member of the Australasian Institute of Mining and Metallurgy. Mr Brown has sufficient experience, which is relevant to the exploration activities, style of mineralisation and types of deposits under consideration, and to the activity which has been undertaken, to qualify as a Competent Person as defined in the 2012 Edition of the “Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves”. Riviere Minerals is consulting to Resolutions Minerals Limited and consents to the inclusion in this announcement of the matters based on their information in the form and context in which it appears.

The Company confirms it is not aware of any new information or data that materially affects the information cross referenced in this announcement and further to “Agreement to Acquire Major US Antimony Project and Placement” on 11 June 2025, “Exceptional Rock Chip and Soil Results from Antimony Ridge” on 15 September 2025, “Exceptional Rock Chip and Soil Results Update” on 24 September 2025, “Significant Gold Discovery at Horse Heaven Project” on 28 October 2025, “Significant Gold Discoveries Continue at Golden Gate” on 3 November 2025, “Golden Gate Discovery Grows with Multiple Gold Intercepts” on 2 December 2025, “Further Ultra High Grade Antimony and Silver Results” on 14 January 2026, “New Gold Discovery at Golden Gate South” on 9 February 2026, “Gold & Significant Tungsten Mineralisation in Drilling” on 17 February 2026,“Exceptional Tungsten Grade Identified in Stockpile Material” on 26 March 2026 and “Antimony Ridge Model Shows Extensive Vein Swarms” on 10 April 2026. The Company confirms that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original announcements.