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RED MOUNTAIN MINING LIMITED
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Red Mountain Mining Limited (RMXFF) Armidale Antimony Target Expanded Ahead of July Drilling

2026-07-08 20:17 ET - News Release

Perth, Australia, July 9, 2026 - (ABN Newswire) - 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, has completed 2D and 3D modelling of dipole-dipole induced polarization (DDIP) data collected during a four-line, 6.2 line-km, orientation IP survey at the Oaky Creek South antimony prospect within the Company's 100% owned Armidale Antimony-Gold Project in New South Wales, Australia. The surveywas designed to test the subsurface electrical response across the coherent antimony-arsenic auger soil anomaly at the Oaky Creek South Main Grid, to extend across the soil anomaly, surface quartz-carbonate-stibnite vein mineralisation and shallow historical pits and shafts at the Oaky Creek South Workings; and to cross a major fault splay of the Namoi Fault that is interpreted to be a potential major feeder structure for the orogenic antimony mineralisation at the Oaky Cree Prospect (Figure 1*).

The survey was completed for Red Mountain collected DDIP data at a spacing of 50m along three 1.6km long, 100m spaced NW-SE oriented lines and one 1.5km long SW-NE oriented line. Gradient array IP (GAIP) data was also collected along the threeNW-SE oriented lines to test the relative effectiveness of the two techniques, as GAIP data can be collected more quickly and therefore is more cost-effective, particularly for large survey areas, but is less effective at detecting narrow, steeplydipping targets, such as those expected for the Oaky Creek vein system. Due to its potential greater effectiveness, Red Mountain prioritised modelling of the DDIP data from the survey, the results of which are presented below. Modelling of the GAIP dataare still in progress.

HIGHLIGHTS:

- 2D and 3D modelling of recently collected dipole-dipole induced polarisation (DDIP) data from Oaky Creek South has revealed a coherent NNE-SSW-striking, steeply SE-dipping chargeability anomaly that extends beneath and southwest from outcropping quartz-carbonate-stibnite veins and shallow historical antimony workings at the Oaky Creek South prospect within Red Mountain's Armidale Antimony-Gold Project in New South Wales, Australia.

- The anomalyshows a peak observed chargeability of over 7.2 mV/V, compared to background values that typically range from 2 to 3 mV/V. It is modelled to extend over a strike extent of at least 400m, compared to the ~120m strike of surface vein mineralisation atOaky Creek South, with a vertical extent of over 100m. It strengthens to the SSW and remains open in that direction.

- The chargeability anomaly will be tested as part of Red Mountain's maiden reverse circulation (RC) drilling program at Oaky Creek, which is scheduled to commence the week beginning Monday 20 July 2026, with Durock Drilling contracted to complete the work.

- The program will comprise up to 32 RC drillholes to a maximum depth of 300m, which will allow initial drill testing of key priority targets defined by the Company's extensive surface geochemical sampling program at Oaky Creek.

- Importantly, the approved drilling program allows the Company the flexibility to adjust drill locations in response to initial results, for example to test for depth or strike extensions to early mineralised intercepts.

- Drilling is expected to be completed in August with assay results from the drilling program expected to be received this Quarter.

- Oaky Creek is RedMountain's most advanced target within the 391 km2 Armidale AntimonyGold Project, located in the Southern New England Orogen of NSW, considered to be Australia's premier antimony mineral province. Previously announced conventional and auger soil sampling and rock chip analytical results of up to 39.3% Sb and 1.09ppm Au from Oaky Creek indicate potential for a large-scale orogenic antimony-gold vein system with a strike extent of ~3km at surface, which is analogous to Larvotto Resources' Hillgrove project, Australia's largest known antimony deposit.

CHARGEABILITY DATA SHOW POTENTIAL STRIKE EXTENSIONS FOR OAKY CREAK SOUTH MINERALISATION

Modelled 2D chargeability cross sections for the four DDIP lines are shown in Figure 2*. The data show a clear coherent chargeability anomaly associated with anomalous auger soil antimony values, outcropping quart-carbonate-stibnite veins and shallow historical workings at the Oaky Creek South Workings (OCSW - Figure 2). The anomaly has a maximum observed chargeability of 7.2 mV/V, compared to background values that typically range from 2 to 3 mV/V, and is most strongly developed on Line 10000N, which is the southernmost line through the OCSW, so remains open in that direction.

The 2D modelling indicates that the chargeability anomaly dips steeply to the southeast, while 3D modelling (Figure 3*) suggests that the anomaly is most strongly developed southwest of Line 10000N, and implies that it extends at least a further 150m beyond it.The anomaly is interpreted to potentially represent the presence of chargeable sulfide within steeply dipping quartz-carbonate-stibnite veins, similar to those mapped and sampled at the surface within and adjacent to the historical workings.

Themodelling therefore suggests that the veins both persist to depths of greater than 100m, and potentially much deeper, below surface and that they extend along strike over a total distance of at least 400m (Figure 3) well beyond the ~120m surface footprint of the outcropping veins and extending the size of the drill target at OCSW.

As can be seen on Figure 2 and Figure 3 the DDIP data also show a weak chargeabilty response beneath the strong antimony-arsenic auger soil anomaly at the Oaky Creek South Main Grid (OCSMG). The maximum observed chargeability of this response, which is most strongly developed near surface on Line 20000E immediately southwest of its intersection with Line 10100N, is 3.91 mV/V. The response appears to have a near-vertical dip on Line 10100N, but has limited depth extent on the other lines. It appears shallow and near flat-lying on Line 20000E, as this line is oriented within and parallel to the strike of the auger soil anomaly at OCSMG.

RESISTIVITY DATA FROM OAKY CREEK

Modelled resistivity values from the DDIP survey vary between 100 ohm-meter and 1200 ohm-meter (Figure 4*), which are within the expected range of resistivities for the metasedimentary host rocks at Oaky Creek South. The valuesare also within the same range of resistivities measured using GAIP by Larvotto Resources (ASX:LRV) (Market Cap ~$660 million) at the analogous Hillgrove antimony-gold deposit over the past twelve months. As detailed in multiple ASX announcements, Larvotto have been using GAIP surveys as a tool to identify extensions to known orogenic antimony-gold mineralisation and as a targeting tool for previously unrecognised parallel mineralised veins. With the benefit of a robust geological framework developed from a large historical drilling database and an extensive network of underground workings, they have detected subtle resistivity variations associated with narrow (~1m) weakly conductive vein-style mineralisation and the broader (up to 20m) resistive silicasericite alteration envelopes that typically surround high grade veins.

Red Mountain does not have any subsurface drilling data from Oaky Creek South and consequently does not have sufficient geological information to confidently interpret the subtle variations in resistivity shown by our DDIP resistivity data (Figure 4). Resistivity is generally lower close to surface along all four lines, which is an expected effect of near surface weathering. There is evidence of nearvertical less resistive (ie: weakly conductive) features that correspond to the chargeability anomalies at OCSW and OCSMG, particularly on Line 10000N. However, these features are weakly developed and do not represent compelling evidence of the presence, orabsence of alteration or antimony mineralisation.

DRILLING CONTRACTORS SECURED TO COMMENCE RC DRILLING PROGRAM IN TWO WEEKS

Red Mountain is pleased to announce that it has engaged Durock to complete the maiden drilling program at Oaky Creek,with a contracted start date of 20 July 2026. The planned program, which has been fully approved by the NSW Resources Regulator, will comprise up to 32 reverse circulation (RC) drillholes to a maximum hole depth of 300m.

The RC drilling program is designed to test four of five compelling orogenic antimony-gold targets defined from Red Mountain's comprehensive surface rock chip, conventional soil and auger soil sampling program, completed over the past 12 months (Figure 5*). The program willdrill test the coherent 300m x 30m Oaky Creek South Main Grid antimony-arsenic auger soil anomaly, which has also returned rock chip results of up to to 39.3% Sb and 1.09ppm Au; the historical workings and outcropping quartz-carbonate-stibnite veinsat the Oaky Creek South Workings and the chargeabilty anomaly that extends to the SSW; the Oaky Creek North Workings; and the Sb-bearing Creek exposure to the north of it. Red Mountain's fifth priority surface geochemical drill target at Oaky Creek,the Oaky Creek North South Extension, is currently under crop, so cannot be accessed at this time.

The approved drilling approval application does not limit Red Mountain to specific collar locations, allowing the Company the flexibility to adjustdrill locations in response to initial results, for example to test for depth or strike extensions to early mineralised intercepts. Initial drillholes are planned to be between 100m and 150m deep, significantly shallower than the maximum requested approved hole depth of 300m, in order to establish continuity of mineralisation from surface. However the maximum depth of 300m will allow for testing of further down-dip extensions of mineralisation, if justified by early results. Orogenic antimony vein systems such as those present at Oaky Creek are known to have significant depth extent, with Larvotto Resources' analogous Hillgrove deposit known to extend over vertical depths of more than 1km9.

The initial drilling program is expected to be completed before the end of August and the Company anticipates that assay results for all drillholes will be received during the current Quarter.

OAKY CREEK REPRESENTS A SIGNIFICANT 3KM LONG OROGENIC ANTIMONY SYSTEM WITH MULTIPLE DRILL READY TARGETS

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 shallow historical pits and shafts at Oaky Creek North and Oaky Creek South.

The Company's initial sampling program at Oaky Creek comprised a 50m 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 2025, 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 CreekNorth 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 5*). 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' 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 late 2025 and early 2026 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 5) during the third quarter of 2026.

RED MOUNTAIN ARMIDALE ANTIMONY-GOLD PROJECT BACKGROUND

Red Mountain's 100%-owned Armidale Antimony-GoldProject lies in the Southern New England Orogen (SNEO) in northeastern New South Wales, approximately west of Australia's largest known antimony deposit, Larvotto's Hillgrove deposit, which is also the 8th largest antimony deposit globally. The SNEOis recognised as Australia's premier Antimony province (Figure 6*).

Red Mountain's Armidale Antimony-Gold Project has an extensive 85km length 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. Oaky Creek is the company's highest priority and most advanced prospect within the project and is one of several known orogenic gold and antimony mineral occurrences within the tenement (Figure 7*).

*To view tables and figures, please visit:
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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.

Contact:

 
Mauro Piccini 
Company Secretary