Red Mountain Mining Ltd (ASX:RMX) Confirms High-Grade Antimony at Armidale Highlighting Strong Project Potential

27 June 2025

Price Sensitive Announcement $

Highlights:

• Multiple High-Grade Antimony rock chip samples at Oaky Creek returned including:
  – 28.34% Sb
  – 28.33% Sb
  – 16.38% Sb
• High-Grade Antimony assay results have been returned from samples collected up to 500m along strike from historical workings, suggesting potential for a large orogenic Antimony mineral system
• Shallow costeaning is planned to expose the bedrock beneath strong soil Antimony anomalies with no visible outcrop
• RMX also plans to undertake a soil and rock chip sampling campaign over the East Hills Antimony and Horsley Station Gold prospects in the southern portion of the Armidale Project
• Gold assays for the Oaky Creek rock samples are pending and expected to be received in July

Overview:

Red Mountain Mining Limited has reported high-grade Antimony rock chip results from Oaky Creek, part of RMX’s 100% owned Armidale Antimony-Gold project (EL9732) in the Southern New England Orogen of New South Wales. Results range up to 28.34% Sb for samples containing quartz-stibnite veining, confirming the high tenor of the mineralisation, and high-grade samples have been collected up to 500m from historical workings, suggesting potential for a large, high-grade, Antimony-bearing orogenic vein system. Similar systems, such as Larvotto’s (ASX: LRV) Hillgrove deposit, also located in the Southern New England Orogen, typically also contain high grade gold mineralisation. RMX has submitted a subset of the Oaky Creek rock chip samples for gold analysis by lead fire assay, with results expected in July.

Extension of Antimony Mineralisation Beyond Historical Workings Confirmed By Antimony Rock Chip Assay Results

During the soil sampling program at Oaky Creek, Red Mountain collected 171 rock chip samples (Refer to ASX Announcement 7 June 2025). Due to sparse outcrop in much of the area covered by the soil survey, the majority of these samples were collected in drainages and close to the Oaky Creek North and Oaky Creek South historical workings (Figure 1).

Figure 1 compares Antimony rock chip and soil results for Oaky Creek. Two samples of quartz-stibnite veining collected more than 2km apart returned the highest values of 28.34% Sb and 28.33% Sb. One of these samples is float from the Oaky Creek South workings, confirming the tenor of the mineralisation mined historically, while the other is from a creek exposure ~500m NNW of Oaky Creek North (Figure 1, 2 and 3). A total of ten rock chip samples contained over 25,000ppm (2.5%) Sb.

The samples were collected from in situ outcropping exposures where possible, but subcrop and float samples were collected where this was not possible. The samples were assayed for antimony and tungsten, using sodium peroxide fusion and ICP-MS finish. Rock chip sample locations, nature (outcrop, subcrop or float) and geochemical results are summarised in Appendix 1.

Red Mountain interprets that the vein-hosted antimony mineralisation mined at Oaky Creek has a significant inferred strike extent, indicating potential for a large tonnage deposit based on:

• the identification of outcropping high-tenor antimony mineralisation in a creek exposure ~500m NNW of the historical workings at Oaky Creek North;
• the spatial correlation between mineralised and anomalous rock chip samples; and
• elevated Antimony in soils.

Mineralised and anomalous rock chip samples show a strong spatial correlation with anomalous (>2ppm) Sb in soils, although due to paucity of outcropping and float material in parts of the survey area, it was not possible to collect rock chips samples across the full length of the approximately 2km long soil anomaly defined for Oaky Creek North or the approximately 1km long anomaly at Oaky Creek South (Figure 1). Most significantly, no outcrop or float material was found within the two new strong >50ppm Sb soil anomalies that were identified by RMX’s sampling. One of these is located ~800m SSE of Oaky Creek North, while the other lies ~300m NW of Oaky Creek South. Both these anomalies warrant further investigation.

Further Work Planned By Red Mountain At Oaky Creek

Based on these highly encouraging initial results, RMX will continue to progress the Oaky Creek prospect, with a program of shallow costeaning planned to expose and sample bedrock beneath those parts of the soil antimony anomaly where no outcrop was observed. RMX will also undertake detailed geological mapping of the costeans and other exposed geology to better understand the relationship between the Namoi Fault system and orogenic vein-hosted antimony mineralisation, with a goal of generating drill-testable targets at Oaky Creek by late 2025. RMX’s future work plans at Oaky Creek will also be influenced by the rock chip gold results, expected in July.