Red Mountain Mining Limited (ASX:RMX) Exceptional Oaky Creek Metallurgy Produces High-Grade 51.8% Antimony Concentrate with 85% Recovery

Red Mountain Mining Limited (ASX:RMX) (OTCMKTS:RMXFF) a Critical Minerals exploration and development company with an established portfolio in Tier-1 Mining Districts in the United States and Australia, announced the results of geochemistry, detailed mineralogical characterisation and a pilot crush, grind and flotation study of a representative bulk sample of quartz-stibnite-carbonate vein material from the high-grade Oaky Creek Antimony prospect in the northern portion of the Company’s 100% owned Armidale Antimony-Gold project in the Southern New England Orogen of New South Wales. HIGHLIGHTS: – Geochemical and detailed mineralogical characterisation and a pilot crush, grind and flotation study of a representative bulk sample of stibnite vein material from the high-grade Oaky Creek Antimony prospect has produced a high-quality concentrate at 51.8%, well above the 30-40% commercial grade, that would be an excellent feed stock for pyrometallurgical processing to produce a saleable Sb metal. The commercial concentrate produced a very high 85% antimony recovery – The ~20kg sample was collected from shallow historical surface pits at Oaky Creek North and is broadly representative of the orogenic antimony mineralisation exposed at surface at Oaky Creek, the depth extent of which will be tested by the upcoming drilling program – The bulk sample had a measured head grade 19.9% Sb and 0.25ppm Au, which is well within the range of mineralised rock chip grab samples from the Oaky Creek prospect, which have returned values of up to 39.3% Sb and 1.09ppm Au. Significantly, the sample returned a below detection result of <0.01% As, suggesting that Arsenic is likely in very low concentrations at Oaky Creek – Mineralogically, TIMA analysis demonstrates that the sample is dominated by quartz (50.5%) with stibnite (25.2%) the next most abundant phase. Oxidised stibnite and Sb (Fe) oxyhydroxides collectively comprise 5.08%, with significant gangue phases including clays (6.41%), ankerite-dolomite (3.04%), calcite (2.66%), feldspars (2.48%), Fe oxides and hydroxides (2.02%), and chlorite (1.43%). Other sulfide and telluride phase are rare, totaling only 0.05% – Based on the mineralogy, a coarse (P80 = 212um) crush was successfully trialed, with a total flotation time of fourteen minutes producing a composite concentrate of 51.8% Sb at a 29.7% mass pull, with an 85% recovery of the metal relative to head grade – Five priority targets which will be tested at the upcoming drilling program at Oaky Creek – Red Mountain advises that Due Diligence activities at the Pioneer Tungsten Project in the United States are progressing well and on schedule, as part of the Company's option agreement over the Pioneer Tungsten Project The ~20kg sample (Figure 1*) was collected from shallow historical surface pits at Oaky Creek North (Figure 2*) and is broadly representative of the orogenic antimony mineralisation exposed at surface at Oaky Creek, the depth extent of which will be tested by an RC drilling program that has been recently approved by the NSW Regulator. Analysis of the bulk sample was completed by ALS Metallurgy (Table 2*) and returned a measured head grade of 19.9% Sb and 0.25ppm Au, which is well within the range of mineralised rock chip grab samples from the Oaky Creek prospect, which have returned values of up to 39.3% Sb and 1.09ppm Au. Significantly, the sample returned a below detection result of <0.01% As, suggesting that this deleterious element is present in very low concentrations at Oaky Creek. etailed mineralogy confirms that almost all antimony occurs in stibnite A portion of the bulk sample was crushed and two size fractions (+212um and -212um) were submitted for Tescan Integrated Mineral Analyzer (TIMA) analysis, while the head sample was submitted for semi-quantitative X-ray diffraction (XRD) analysis. The XRD analysis of the head sample indicated that 59% of the sample comprised quartz, with 21% stibnite (Sb2S3), 1% stibiconite (Sb3O6(OH)) and 2ppm Sb in soil anomaly extending both north and south of the historical workings at Oaky Creek North and a similarly-oriented ~1km long >2ppm Sb in soil anomaly extending north from the Oaky Creek South workings. Sampling campaigns at Oaky Creek, returned multiple rock chip samples with values of over 25% Sb and 0.1g.t Au for five different areas, with mineralised and anomalous rock samples showing a strong spatial correlation to the antimony soil anomaly (Figure 2*). When considered collectively, the soil and rock chip results indicate a significant orogenic antimony mineral system with a strike extent of 3km, which is analogous to Larvotto Resources’ (ASX:LRV) (Market Cap. ~AU$610 million) Hillgrove Project, which lies east of Red Mountain’s project area. Red Mountain’s ~1300 sample infill hand auger soil sampling campaign across the full ~3km strike extent of the Oaky Creek prospect was completed across the past two quarters to tighten the Company’s existing 100m x 50m spaced soil grid in order to better constrain individual high priority drill targets. This detailed systematic work has allowed the company to define five high priority orogenic antimony targets for drill testing at Oaky Creek (Figure 2*) during the second quarter of 2026. *To view tables and figures, please visit: https://investorhub.redmountainmining.com.au/announcements/7551891 Red Mountain Mining Limited Announcements page: https://investorhub.redmountainmining.com.au/announcements Mauro Piccini Company Secretary