Red Mountain Mining (ASX:RMX) Returns Strong Antimony and Gold Results In NSW

15 October 2025

Price Sensitive Announcement $

Highlights:

• Rock chip sampling of outcropping mineralisation at the Oaky Creek prospect, part of the Armidale Antimony-Gold Project returned further strong results highlighted by:
  o 36.3% Sb at Oaky Creek North
  o 18.8% Sb at Oaky Creek North
  o 23.0% Sb and 0.36g/t Au at Oaky Creek South
• Initial rock chip sampling at the previously unsampled East Hills prospect in the south of EL9372 returned a best result of 9.9% Sb, with anomalous samples collected over a strike
  extent of 70m
• Initial rock chip sampling of the nearby historical Horsley Station gold workings returned up to 0.25g/t Au and evidence of ultramafic lithologies, a preferred host for gold mineralisation along the Peel Fault
• The strong spatial correlation between Antimony and Gold supports RMX’s exploration
  model for the Oaky Creek prospect, targeting a vein-style orogenic antimony-gold deposit, which is considered analogous to Larvotto Resources’ (ASX: LRV) Hillgrove project, Australia’s largest Antimony deposit
• Evidence of Antimony and Gold mineralisation from multiple prospects across the length of the project highlights the strong potential of the tenement to host multiple orogenic antimony-gold systems associated with the Peel Fault system and its related splays
• The Armidale Antimony-Gold Project comprises a large, strategic tenure covering nearly 400km2 of highly prospective ground, west of Larvotto (ASX: LRV) ($550m market cap)
• RMX well positioned to leverage increased Australian and US Government interest in critical minerals, with Utah Antimony Project exploration set to commence
• Red Mountain continues to assess value accretive critical metals assets in the United States is progressing its US Stock Market listing, given the significant interest globally in the Company’s projects

Overview:

Red Mountain Mining Limited, a gold and critical minerals exploration and development company with a focus on the United States and Australia, is pleased to announce additional rock chip analyses for samples collected at three prospects within the Company’s 100% owned Armidale antimony-gold project (EL9732) in the Southern New England Orogen of northeast New South Wales.

Analytical results of up to 36.3% Sb and 0.36g/t Au have been received for additional rock chip samples from the Oaky Creek prospect in the northern portion of RMX’s tenement (Figure 1), where the company previously reported antimony in soils results of up to 333ppm Sb1 and rock chip values of up to 39.3% Sb and 1.09g/t Au2.

RMX has also collected its initial rock chip samples from the southern portion of the project area (Figure 1), with 20 samples analysed from the previously unsampled East Hills antimony prospect, with a best result of 9.9% Sb, and eight rock chip samples from the Horsley Station gold prospect recording up 0.25g/t Au.

Further strong results for Oaky Creek

Rock chip sampling at Oaky Creek North and Oaky Creek South was undertaken during the collection of approximately 250 hand auger soil samples spaced at 10m and 20m across the Oaky Creek South prospect (Figures 2 and 3), following up antimony soil anomalies defined by initial 50m x 100m spaced soil sampling reported in June 2025. Analytical results for the hand auger sampling program are expected to be received before the end of October.

Rock chip samples were analysed at Intertek’s Townsville laboratory for Sb, Ag, As and W using sodium peroxide fusion and ICP-MS finish, and for Au using a 50g fire assay charge and ICP-OES finish. All analytical results are listed in Appendix 1, and gold and antimony results are shown in Figures 2 and 3.

Eight new samples were collected from the Oaky Creek North area, from both the immediate surroundings of the historical workings and from the antimony bearing creek exposure ~500m northnorthwest of the workings. Five of these samples were found to contain >1% Sb (Figure 2B), with a best value of 36.3% Sb, which is the highest antimony result recorded to date for Oaky Creek North.

A sample of weathered outcrop or subcrop (AAR189, Appendix 1) collected ~500m northwest of the Oaky Creek South workings contains 23.0% Sb and 0.36g/t Au. This sample is located within 6m of two float samples that were reported on 2 October3 to contain 39.3% Sb and 0.16g/t Au, and 33.5% Sb and 1.09g/t Au, respectively (Figures 2C and 3C). The close proximity of in situ mineralisation to the mineralised float samples supports RMX’s previous interpretation that the float was collected close to source.

Antimony-mineralisation confirmed at East Hills

As previously reported, RMX has also completed initial soil sampling over the East Hills antimony prospect in the southern portion of EL9732. Results are anticipated before the end of October for a total of 78 soil samples that were collected on a 50m x 100m spaced grid centred on the historical workings at the prospect (Figure 4). During this program, the company also collected 20 rock chip samples over the prospect (Appendix 1) and confirmed the presence of high-grade antimony mineralisation, with a best result of 9.9% Sb (Figure 4). A further two samples with anomalous (>500ppm) antimony were collected ~70m north-northwest along strike from the mineralised sample, indicating that antimony mineralisation at East Hills extends well beyond the small historical workings.

Gold analyses for all samples were low, with a best result of 0.016g/t Au (Appendix 1).

Anomalous gold and prospective ultramafic host rocks confirmed at Horsley Station

RMX collected eight rock chip samples from the historical workings and nearby outcrops at Horsley Station. A sample of quartz-fuchsite vein material from the workings returned an anomalous gold value of 0.25g/t Au, while a nearby sample of similar material contained anomalous antimony of 0.18% (Figure 5). An outcrop of ultramafic rock was also sampled ~25m east of the workings (Figure 5).

Although this sample is not mineralised, ultramafic lithologies are recognised as the preferred host for gold mineralisation along the Peel Fault system and the exposure supports RMX’s interpretation that magnetic highs at Horsley Station and Horsley North (Figure 1) represent structurally bound ultramafic bodies

Next steps for the Armidale Antimony-Gold Project
Subject to positive results for the pending assays from Oaky Creek South, RMX will undertake a similar program of soil and rock chip sampling over the Oaky Creek North soil anomaly to define prospective drill targets. Further work is also anticipated at East Hills to follow up the initial positive antimony rock chip results, with next steps to be finalised following receipt and interpretation of the results of the soil sampling program.

As previously reported,soil and rock chip sampling is also planned for the Horsley Station and Horsley North gold targets, where land access has now been secured. As reported in August 20255, RMX is also working to secure land access to ground truth stibnite and jarosite spectral anomalies across EL9732, in particular those that lie adjacent to known mineralisation and/or are along the known major Peel, Namoi and Cobbadah faults.

Full ASX Announcement: https://hotcopper.com.au/threads/ann-strong-antimony-grades-and-gold-results-at-armidale-project.8825821/