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RED MOUNTAIN MINING LIMITED
Symbol	RMXFF
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Red Mountain Mining Limited (RMXFF) Exceptional Assays Define Multiple Antimony Drill Targets

2026-03-29 18:10 ET - News Release

Perth, Australia, Mar 30, 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, is pleased to announce final assays from auger soil sampling at the Oaky Creek prospect at the Company's 100% owned Armidale Antimony-Gold project in New South Wales, generating five high-confidence Antimony drill target regions across the prospect.

HIGHLIGHTS:

- Red Mountain's comprehensive and systematic work has allowed the Company to define five high priority orogenic Antimony targets for drill testing at Oaky Creek next quarter

- A significant large-scale orogenic antimony-gold vein system with a strike extent of ~3km at surface has now been delineated by these extensive results with drilling to commence

- The new auger soil results include additional sampling close to the historical workings at Oaky Creek South, with multiple samples returning values of over 500ppm Sb, including exceptionally high soil values of up to 1.16% Sb and 612ppm As

- On the Oaky Creek South Main grid, infill and extensional auger sampling of the previously reported coherent, NE-trending ~30m wide Antimony-Arsenic auger soil anomaly returned further strong results of up to 356ppm Sb and 413ppm As, with the anomaly now extending 300m in strike extent and remaining open to the northeast

- Auger soil results at Oaky Creek North and further to the north highlight strong Antimony-Arsenic anomalies around mapped quartz-carbonate stibnite veins, returning values of up to 3,011ppm Sb and 859ppm As

- Preparations are currently being finalised for drilling to commence at Oaky Creek

- Met-test results for the Oaky Creek Antimony Prospect are expected to be received in April

- Further assay result is expected in April for the Thompson Falls Antimony Project in the United States, following recently announced initial high-grade Antimony results

- Antimony prices remain well supported by the classification as a critical defence mineral with direct applications in ammunition, weapons systems, alloys and flame-retardant materials, underpinning strong long-term demand and increasing efforts by Western nations to secure reliable and independent supply chains

The new auger soil results include additional sampling close to the historical workings at Oaky Creek South, with multiple samples returning values of over 500ppm Sb, with values of up to 1.16% Sb and 612ppm As (Figure 2; Appendix 1*). The new results strengthen and support prior results, from a single line of eight auger samples taken over the workings in 2025, which returned values of up to 1.36% Sb and 351ppm As. These antimony values are exceptionally high soil sample assays. As per Figure 2*, antimony values of >100ppm are closely related to the mapped quartz-carbonate-stibnite veins.

Auger Program Defines Five High-Confidence Antimony Drill Targets at Oaky Creek

On the Oaky Creek South Main Grid,~400m northwest of the workings, infill and extensional auger sampling of the previously reported coherent, NE-trending ~30m wide antimony-arsenic auger soil anomaly returned further strong results of up to 356ppm Sb and 413ppm As (Appendix 1*), with the anomaly now extending 300m in strike extent and remaining open to the northeast (Figure 2, Figure 3*). The results to date at Oaky Creek South highlight the Main Grid soil anomaly and associated quartz-carbonate-stibnite veins and the Oaky Creek South workings as priority targets for drill testing, which is planned for the second quarter of 2026. In addition, anomalous arsenic in auger soil samples at Oaky Creek South appears to form a halo across and surrounding the anomalous antimony that is closely spatially associated with vein-style quartz-carbonate-stibnite mineralisation (Figure 2*). Multiple arsenic anomalies remain open at the edges of the current coverage at Oaky Creek South between the historical workings and the Oaky Creek South Main Grid and further surface sampling to the east and west of the current coverage may define additional antimony anomalies that would also be potential drill targets. The new results are for approximately 900 additional auger soil samples collected over conventional soil anomalies at Oaky Creek South and Oaky Creek North, more than tripling auger soil coverage from approximately 430 samples, which were reported in November 2025 and earlier this month (Figure 1*). The comprehensive program has successfully produced multiple drill ready targets for Red Mountain.

Additional drill targets confirmed for Oaky Creek North

The new auger soil results encompass the remainder of the ~1.5km conventional soil anomaly at Oaky Creek North (Figure 4*), including the historical workings and an antimony-bearing creek outcrop (Figure 5*). Both prospects feature multiple mineralised (>0.5% Sb) rock chip samples and exposed quartz-carbonate-stibnite veins. The auger soil results show narrow, strong antimony-arsenic anomalies related to the main mapped veins at both prospects (Figure 5*), with peak values of 3,011ppm Sb and 859ppm As immediately adjacent to the creek outcrop and 525ppm Sb and 166ppm As at the Oaky Creek South workings (Appendix 1*).

Initial auger soil results from the southern end of the conventional soil anomaly at Oaky Creek North, reported earlier in the month, returned multiple anomalous values of up to 137ppm Sb and 334ppm As (Figure 4*), defining a coherent NNW-trending antimony auger soil anomaly that broadly correlates with the earlier conventional soil results and the distribution of mineralised stibnite-bearing rock chip samples (refer to Figure 1*).

The auger soil antimony-arsenic anomalies at the creek outcrop and the Oaky Creek North Workings both extend over a strike extent of 100-200m, indicating potential for a significant antimony-bearing orogenic vein system. Both targets, as well as the previously defined "Oaky Creek N South Extension" target at the southern end of the conventional soil anomaly, represent priority targets for drill-testing planned for the upcoming quarter.

Oaky Creek represents a significant 3km long orogenic antimony system with multiple drill-ready targets

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 Creek North 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 1*). 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' (Market Cap. ~AU$515 million) Hillgrove Project, which lies east of Red Mountain's project area.

Red Mountain's ~1,300 sample infill auger soil sampling campaign across the full ~3km strike extent of the Oaky Creek prospect (Figure 1*) was completed across the past two quarters 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 target regions at the prospect, for drill testing at Oaky Creek next quarter.

Red Mountain Armidale Antimony-Gold Project background

Red Mountain's 100%-owned Armidale Antimony-Gold Project lies in the Southern New England Orogen (SNEO) in northeastern New South Wales, west of Australia's largest known antimony deposit, Larvotto's (ASX:LRV) Hillgrove deposit, which is also the 8th largest antimony deposit globally.

The SNEO is recognised as Australia's premier Antimony province (Figure 6*). Antimony occurs in hydrothermal quartz veins, breccias and stockworks, often with associated gold and/or tungsten mineralisation. 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 pprospects.

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 (Figure 7*).

*To view tables and figures, please visit:
https://abnnewswire.net/lnk/5H33SXAC

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