Red Mountain Mining Ltd (ASX:RMX) Hits Outstanding Antimony Results up to 34.3% at Oaky Creek

15 January 2026

Price Sensitive Announcement $

Highlights:

• High grade Antimony (Sb) mineralisation returned from rock chip samples from Oaky Creek Prospect in the New England Oregon, NSW. Highlights include:
  o 34.3% Sb (AAR239) – (Figure 1, Figure 3)
  o 23.1% Sb (AAR237) – (Figure 2)
  o 19.1% Sb (AAR240)
• The Oaky Creek prospect continues to return exceptional Antimony assay results with 11 of 13 samples collected from the Oaky Creek North soil anomaly returning in excess of 1.9% Sb.
• Strongly Antimony mineralised rock-chip samples highlight a 1.6km strike extent, NNW-trend of at Oaky Creek North, providing indications of the presence of a large-scale orogenic antimony-gold vein system, analogous to Larvotto Resources’ Hillgrove project, at surface.
• Assay results for the December 2025 auger program at Oaky Creek North and South are expected to be received this month and additional field work is planned to complete the auger sampling program at both Oaky Creek prospects.
• Red Mountain anticipates that the auger sampling will define multiple orogenic Antimonygold targets for drill testing at Oaky Creek during the first half of 2026.
• The Company plans a high-resolution airborne magnetic-radiometric survey to better define additional orogenic Antimony and or Gold targets.
• The Australian Government has prioritised Antimony in its A$1.2B Critical Minerals Strategic Reserve and Strategy, providing strong policy validation for RMX’s Antimony projects.

Overview:

Red Mountain Mining Limited, a Critical Minerals exploration and development company with an established and growing portfolio in Tier-1 Mining Districts in the United States and Australia, is pleased to announce a further tranche of outstanding antimony rock chip geochemistry results from the Oaky Creek prospect within the Company’s 100% owned Armidale antimony-gold project in the Southern New England Orogen of northeast New South Wales.

Eleven of thirteen grab samples collected across the southern half of the 1.2km-long Oaky Creek North soil anomaly returned antimony values of greater than 1.9% Sb (Table 1), with the highest recorded value of 34.3% Sb for sample AAR239 (Figure 3)

Samples were analysed 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 Table 1. The majority of samples also contain anomalous arsenic (>100ppm As), with a peak value of 467ppm As; and all contain detectable gold, with anomalous values of over 100ppb Au (0.1g/t Au) recorded for two samples (Table 1). The antimony-arsenic-gold association present in the samples is consistent with the Company’s primary exploration target of a vein-style orogenic antimony-gold deposit, which is considered analogous to Larvotto Resources’ (ASX: LRV; Market Cap $610M) Hillgrove project, Australia’s largest Antimony deposit, which lies east of Red Mountain’s Armidale Project.

Soil and rock chip sampling at Oaky Creek define a 3km long orogenic Sb-Au system

The Oaky Creek prospect features quartz-carbonate-stibnite veins and breccias hosted within a tightly folded and faulted sequence of metamorphosed Carboniferous mudstone, siltstone and fine sandstone The mineralisation has been targeted by two groups of small, shallow historical pits and shafts at Oaky Creek North and Oaky Creek South, which are thought to date from the late 19th Century.

Since acquiring the project in December 2024, RMX has completed three field campaigns at the Oaky Creek prospect. The Company’s initial sampling program at Oaky Creek comprised a 50 x 100m spaced grid soil sampling program centered on a major splay of the Namoi Fault, accompanied by rock chip sampling. As initially reported in June 20251 , the soil sampling defines a coherent, ~1.5km long, 100- 200m wide, NNW-trending >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

Initial rock chip sampling, reported in June2 and July 20253 , returned values of up to 28.3% Sb and 0.54 g/t Au, with mineralised and anomalous rock chip samples showing a strong spatial correlation to the antimony soil anomaly (Figure 4), and high grade (>25% Sb) mineralisation found to be outcropping in a creek exposure 500m NNW of the historical workings at Oaky Creek North. A second sampling program was undertaken in August and September 2025, with the collection of additional rock chip samples at Oaky Creek South and Oaky Creek North, returning even stronger results of up to 39.3% Sb8 and 1.09g/t Au4 and confirming the presence of a high-grade antimony mineralisation with associated gold ~500m northwest of the Oaky Creek South workings. As reported in late November 20255 , initial soil auger sampling by RMX over the mineralisation to the northwest of Oaky Creek South defined a coherent northeast-trending Sb-As anomaly, up to approximately 30m in width and 200m in length, which parallels and overlaps the extent of mapped quartz-carbonate-sulfide veins, suggesting that the auger soil sampling is able to directly mapping near-surface mineralisation. The core of the anomaly is defined by nine samples containing >100ppm Sb, with a peak value of 1201ppm Sb; and 27 samples containing >100ppm As, with a maximum value of 1040ppm As.

The receipt of the most recent high grade antimony results over the southern end of the soil anomaly at Oaky Creek North means that strongly antimony mineralised rock-chip samples have now been collected along a NNW-trending strike extent of 1.6km at Oaky Creek North (Figure 4), indicating the presence of a large-scale orogenic antimony-gold vein system at surface that provides a compelling target for drill testing

Comprehensive auger soil sampling in progress to define priority targets for drilling

The new Oaky Creek North samples were collected in December 2025 during the first phase of a 50m x 20m spaced auger soil sampling designed to tighten Red Mountain’s existing 100m x 50m spaced soil grid to better constrain individual high priority drill targets.

The samples collected in December represent the first batch of a comprehensive hand auger soil sampling program (Figure 5) that is designed to:

• Cover the full 1.2km strike extent conventional soil antimony that was the Company’s primary initial target at the Oaky Creek prospect.
• Test the extension of the strong 200m-long antimony-arsenic auger soil anomaly at Oaky
  Creek South, which is open to the northeast; and
• Sample across the area between the previous auger sampling and the historical workings at Oaky Creek South, where conventional soils define a weak but coherent antimony anomaly and the previous auger sampling showed increasing arsenic towards the edge of coverage, a potential vector towards antimony-gold mineralisation.

Assay results for the December 2025 auger samples are expected to be received early this quarter with follow up field work to commence shortly thereafter to complete the full auger sampling program at Oaky Creek North and Oaky Creek South.

Red Mountain anticipates that the auger sampling program at Oaky Creek will be completed, including receipt of all analytical results, before the end of Q1 2026 and that the results will define multiple orogenic antimony-gold targets for drill testing at Oaky Creek during the first half of 2026.

Next steps for the Armidale Antimony-Gold Project

Oaky Creek is the company’s highest priority prospect within the project and is one of several known orogenic gold and antimony mineral occurrences within the tenement (6) that have strong structural, lithological and mineralogical similarities to Larvotto’s (ASX: LRV; Market Cap $610M) Hillgrove deposit, 100km to the East, which is Australia’s largest antimony-gold deposit.

The Company is prioritising the advancement of the Oaky Creek prospect, which will be drill tested during 2026, while concurrently commissioning a high resolution airborne magnetic-radiometric survey over the tenement to improve data resolution and better map the structural architecture, to define additional orogenic antimony and/or gold targets. The plan for the survey is currently being prepared, with the dataset expected to be acquired during this quarter.

The Company expects that the improved resolution magnetic and radiometric data will allow Red Mountain to better identify locations for initial soil sampling at the Horsley Station and Horsley North gold targets and possible follow up work at the East Hils antimony-gold prospect, which has returned initial rock chip results6 of up to 9.9% Sb and soil results7 of up to 109ppm Sb and 304ppm Sb. The locations of these targets are shown on Figure 6.

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