Red Mountain Mining Limited (RMX.AX) Exploration Commences at Armidale with New Antimony Observed

NEW ANTIMONY VEINS IDENTIFIED AS EXPLORATION COMMENCES AT ARMIDALE ANTIMONY-GOLD PROJECT

Perth, Dec 4, 2025 AEST (ABN Newswire) - Red Mountain Mining Limited (ASX:RMX) (RMXFF:OTCMKTS) announced the commencement and immediate indicative success in its soil sampling program at Oaky Creek, one of numerous targets at the Company's 100% owned Armidale Antimony-Gold project, based in New South Wales, Australia.

HIGHLIGHTS

- Red Mountain has immediately commenced an expanded exploration program at the Oaky Creek prospect within the Armidale Antimony-Gold Project which aims to define orogenic Antimony-Gold targets for drill testing in 1H 2026

- New visible stibnite and stibiconite (visually estimated at up to approximately 65% combined*) uncovered close to the southern end of the Oaky Creek North soil anomaly

- The Oaky Creek North sampling is targeting the 1.2km strike featuring Antimony in-soils that was the Company's primary initial target at the Oaky Creek prospect.

- At Oaky Creek South, the additional sampling will expand the existing coverage to include the remainder of the coherent Antimony soil anomaly

- The auger sampling program will comprise approximately 900 samples and is planned for completion during December, with all results expected to be received before the end of the March Quarter of 2026

US Critical Minerals Portfolio Fast-Track Progress

- RMX's US Critical Minerals assets continue to advance with assay results expected by the end of January 2026 and potential expansion opportunities in the pipeline with a focus on Antimony/Gold

- A successful $1.35m placement which received strong demand from sophisticated and family office investors has strengthened Red Mountain's balance sheet to fund planned exploration activities in 2026

Antimony mineralisation has been uncovered during the first two days of operation that are visually estimated* to contain up to 60% stibnite (Sb2S3) and 5% of its oxide stibiconite (Sb3O6). RMX commenced sampling this week at the Oaky Creek North strike extent. Multiple mineralised samples were discovered and are found below (Figure 1*; Table 1 - assays are expected in early January 2026).

Oaky Creek is one of the Company's highest priority prospects within the Armidale Antimony-Gold Project and is one of several known orogenic gold and antimony mineral occurrences within the tenement (Figure 7*) that have strong structural, lithological and mineralogical similarities to Larvotto's (ASX:LRV) (Market Cap $630M) Hillgrove deposit to the East, which is Australia's largest antimony-gold deposit. Red Mountain's project features multiple prospects and covers nearly 400km2 of highly prospective ground in the New England Oregon, Australia's premier Antimony District.

Soil and rock chip sampling at Oaky Creek defines a 3km long orogenic Stibnite-Gold system The Oaky Creek prospect has been targeted by two groups of shallow historical pits and shafts at Oaky Creek North and Oaky Creek South, which are thought to date from the late 19th Century, with limited exploration since.

Since acquiring the project in December 2024, RMX has completed two 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 centred on a major splay of the Namoi Fault, accompanied by rock chip sampling. As initially reported in June 2025, the soil sampling defines a coherent, ~1.5km long, 100-200m wide, NNW-trending >2ppm Stibnite(Sb) in soil anomaly extending both north and south of the historical workings at Oaky Creek North and a similarly-oriented ~1km long >2ppm Stibnite(Sb) in soil anomaly extending north from the Oaky Creek South workings (Figure 2*), indicating a significant orogenic antimony-gold mineral system with a strike extent of 3km.

Initial rock chip sampling, reported in June and July 2025, 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 2*), 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% Sb and 1.09g/t Au and confirming the presence of a high-grade antimony mineralisation with associated gold ~500m northwest of the Oaky Creek South workings.

Antimony rock chip sample results are shown relative to the soil geochemistry in Figure 2*, along with a summary of the best rock chip antimony and gold results for the Oaky Creek prospect.

Initial sampling at Oaky Creek South highlights significant potential

In late August and early September, RMX's field team collected a total of approximately 250 soil samples spaced at 10m and 20m across two grids at Oaky Creek South: "Oaky S Main" (193 sample sites) and "Oaky S Minor" (45 sample sites); as well as a single line of eight samples collected across the Oaky Creek South workings.

The Oaky S Main grid is located approximately 400m north-northwest of the historical pits and shafts at Oaky Creek South. The grid was targeted on a conventional soil sample anomaly with a peak value of 333ppm Sb (Figure 3*), which is associated with multiple mineralised float and in-situ rock chip samples, with maximum values of 39.3% Sb and 1.09g/t Au. The Oaky S Minor grid is centred ~200m southeast of the Oaky S Main Grid, targeting a soil sample located 300m north of the Oaky Creek South workings with a peak value of 46ppm Sb and 65ppm As (Figure 4*).

As reported in November, the auger samples collected from the Oaky S Main grid define 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 map near-surface mineralisation. The core of the anomaly is defined by nine samples containing >100ppm Sb, with a peak value of 1,201ppm Sb; and 27 samples containing >100ppm As, with a maximum value of 1,040ppm As (Figure 5*). The anomaly and vein sets appear to be offset along an approximately NW-striking fault, which may represent a smaller splay structure off the NNW-striking major Namoi Fault splay that lies approximately 400m east of the grid (refer to Figure 4*) and is thought to be the primary controlling structure and fluid conduit for the Oaky Creek antimony-gold system. The Oaky S Main grid hand auger antimony arsenic soil anomaly is open to the northeast, owards the Namoi Fault splay.

The Oaky S Minor grid is strongly anomalous for arsenic, with six samples containing >100ppm As, with a maximum value of 257ppm. The samples define an anomaly, open to the southwest, that parallels the Sb-As anomaly in the main grid, and may represent the fringes of a similar antimony rich vein system (Figure 5*).

The strong positive results of the initial auger sampling at Oaky Creek South demonstrates both the effectiveness of this method to directly map near-surface mineralisation and validity of the initial conventional soil sampling as a targeting tool. It is anticipated that the results of this sampling will allow the Company to identify priority targets for drill testing during the first half of 2026.

Sampling underway at Oaky Creek North - Antimony mineralisation sampled

The 1.2km long, NNW-striking coherent Oaky Creek North mineralisation was identified as the priority target from Red Mountain's initial soil sampling program at Oaky Creek and auger sampling commenced at the southern end of the anomaly earlier this week (Figure 5*). Approximately 400 samples will be collected along the full extent of the anomaly (Figure 6*) at a spacing of 20m on eastwest oriented lines located 40m apart.

As noted above, multiple exceptional antimony mineralised samples have been collected by the field team during the first two days of sampling at Oaky Creek North (refer to Table 1*). The newly collected stibnite-bearing samples occur in an area where mineralised material has not previously been observed (Figure 6*). They correspond well to peak of the soil antimony anomaly and define a similar north-northwest strike.

Next steps for the Armidale Antimony-Gold Project

Red Mountain anticipates that the hand auger soil sampling program across Oaky Creek North and Oaky Creek South will be completed during December, with all results expected to be received before the end of the March Quarter of 2026. Based on the results from the previous auger sampling at Oaky Creek South, the Company 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 is prioritising the advancement of the Oaky Creek prospect, 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 Company expects to acquire data during the first quarter of 2026.

Red Mountain expects that the improved resolution magnetic and radiometric data will allow Red Mountain to better target planned 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 results of up to 9.9% Sb and soil results of up to 109ppm Sb and 304ppm Sb. The locations of these targets are shown on Figure 1*.

The improved data will also allow the company to critically evaluate and rank stibnite and jarosite satellite multispectral anomalies across the project that were reported in August 10 to identify additional areas for priority ground follow up.

RMX Armidale Antimony-Gold Project Background

Red Mountain's 100%-owned Armidale antimony-gold project (EL9372) lies west of Australia's largest known antimony deposit, Larvotto's (ASX:LRV) Hillgrove deposit, which is also the 8th largest antimony deposit globally.

The New England Orogen is recognised as Australia's premier Antimony province (Figure 7*). Antimony occurs in hydrothermal quartz veins, breccias and stockworks, often with associated gold and/or tungsten mineralisation.

The Armidale Antimony-Gold Project extends for 85km along the western side of the Peel Fault. The geology of the project area is dominated by isoclinally folded Carboniferous metasediments of the Tamworth Belt, which is a forearc basinal package related to west-dipping subduction of oceanic crust beneath the Lachlan Orogen. Ultramafic melanges of the Great Serpentinite Belt, which outcrop along the Peel Fault, are considered to be remnants of this oceanic crust. The Peel Fault System has recognised world-class mineral potential, with over 400 known orogenic gold and base metal mineral occurrences along its over 400km strike extent, but is underexplored, with less than 200 mostly shallow drillholes over its length, the majority of which are focused on discrete prospects.

Red Mountain Successfully Completes Funding Initiative

Red Mountain's immediate reporting of visible stibnite* on the second day of exploration has delivered highly encouraging initial results for the technical team, this follows the Company's announcement on 27 November 2025 indicating the current fast-tracked program at the Armidale Antimony-Gold Project.

The Company has received firm commitments from professional, sophisticated and family office investors in a placement which was heavily oversubscribed, raising $1.35m at a 13% discount to the last trade of $0.03 per share, and 20% discount to the 15-day VWAP, through the issuance of approximately 51.9m shares under its current LR7.1A placement capacity. Placement participants will receive 1-for-2 attaching unlisted options at a strike of $0.05 and expiry of 31 December 2028, which will be issued subject to shareholder approval at an upcoming General Meeting.

Funds raised will be applied towards continued exploration at the Armidale Antimony-Gold Project.

In addition, a portion of the proceeds will support ongoing exploration across Red Mountain's US Critical Minerals Projects, together with the provision of general working capital to underpin the Company's operational and corporate activities.

Xcel Capital acted as lead manager to the placement and will be issued 8m lead manager shares, also subject to shareholder approval at the next General Meeting.

The Company thanks its shareholders both in Australia and the United States, and its advisors for their ongoing support as Red Mountain seeks to fast-track its Critical Minerals expansion.

*To view tables and figures, please visit:
https://abnnewswire.net/lnk/8659CD2I

About Red Mountain Mining Limited

Red Mountain Mining Limited (ASX:RMX) is a mineral exploration and development company. Red Mountain has a portfolio of US, Canada and Australia projects in Critical Minerals and Gold. Red Mountain is advancing its Armidale Antimony-Gold Project in NSW, Utah Antimony Project in the Antimony Mining District of Utah, US, Fry Lake Gold Project and US Lithium projects.

   

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