IP Survey & RC Drilling Results at Rhyolite Dome

Great Western Mining Corp. plc

28 January 2026

 

Great Western Mining Corporation PLC / AIM: GWMO / Euronext Growth: 8GW

28 January 2026

GREAT WESTERN MINING CORPORATION PLC

("Great Western", "GWM" or the "Company")

IP Geophysical Survey & RC Drilling Programme Completed at Rhyolite Dome,

Olympic Gold Project

Great Western Mining Corporation PLC, a strategic minerals exploration and development company, announces the results of an IP geophysical survey and the assay results of a reverse circulation ("RC") drilling programme at Rhyolite Dome, a previously undrilled prospect, which forms part of its Olympic Gold epithermal precious metals project in the Walker Lane trend of Nevada ("Rhyolite Dome").

HIGHLIGHTS

·    Six IP survey lines completed, identifying a near-surface resistivity anomaly associated with a fault and a deeper untested chargeable feature at more than 300 m depth.

·    Four shallow RC holes totalling 2,315 ft (706 m) intersected silicified, hydrothermally altered volcanic rocks consistent with an epithermal system.

·    Low-grade gold and more significant silver mineralisation returned, including 70 ft (21.3 m) at 1.64 g/t Ag.

·    Elevated pathfinder elements (Ba, As, Mn, Li, Sb) indicate shallow levels of a hydrothermal system.

·    Geological model to be refined for better targeting of the deeper chargeable IP anomaly.

Great Western Chairman Brian Hall commented: "We have already extensively drilled at the Olympic Gold Project in the region of the prolific but now worked-out OMCO Mine vein, intercepting gold at an extension of the mine and at the Trafalgar Hill prospect on the western side of the claims area.  The Great Western team regards Rhyolite Dome, one of the eight currently identified prospects across the 800 acre (324 ha) claims area, to be a prospect that merits further assessment and, in the second half of 2025, four initial shallow holes were drilled following an IP survey to launch a maiden exploration programme. While this first-pass drilling didn't return significant precious-metal intercepts, it has materially advanced our geological understanding. Combined with the high-quality geophysical dataset, these results provide a strong technical foundation to refine targeting and design the next phase of exploration at this highly prospective epithermal gold prospect."

DETAILS

The Olympic Gold Project lies in a historically prolific low-sulphidation epithermal gold district within the Walker Lane Trend, centred around the past-producing OMCO Mine, which delivered exceptionally high grades of 25-30 g/t Au between the two world wars.  This is an area of gold-quartz veining and brecciation associated with silica flooding.

Rhyolite Dome is located along the Olympic Gold fault zone, approximately 1.5km southeast of the OMCO Mine. The area shows coincident geophysics (IP survey) and soil geochemistry anomalies, together with outcropping indications of geological and structural prospectivity indicators, as previously reported in 27 March 2024.

Six IP geophysical survey lines were successfully completed at Rhyolite Dome (Figures 1 and 2). Data inversions identified a near-surface zone of anomalous resistivity that coincides with a mapped fault zone, as well as a chargeable feature at depth of approximately 25mrad located more than 300 m below surface.

Four shallow RC drill holes were completed at Rhyolite Dome in November 2025 totalling 2,315 ft (706 m) (Figure 1). Drilling primarily targeted the near-surface resistivity anomaly defined by the IP survey, while the deeper chargeable feature was ultimately beyond the effective reach of the contracted RC rig from the permitted drill pads. Drilling intercepted several intervals of silicified rhyolite with locally common pyrite, together with hydrothermally altered volcanic rocks. Low concentrations of gold were encountered, with maximum intercepts of 5 ft (1.5 m) at 0.12 g/t Au and 5 ft (1.5 m) at 0.11 g/t Au in hole RDRC005 (Table 1). More significant silver intercepts were returned, including 70 ft (21.3 m) at 1.64 g/t Ag and 0.03 g/t Au in hole RDRC004, as well as 15 ft (4.6 m) at 1.13 g/t Ag and 0.05 g/t Au (Table 1).

Elevated concentrations of pathfinder elements were recorded across the drill hole assays, including barium (Ba, consistently greater than 1,000 ppm), arsenic (As, consistently greater than 200 ppm and up to 3,820 ppm), manganese (Mn, with several intervals exceeding 1,000 ppm), lithium (Li, consistently greater than 50 ppm) and antimony (Sb, with various intervals above 100 ppm). These geochemical signatures are consistent with the shallow levels of a hydrothermal system.

On the basis of these results, the geological framework for the Olympic Gold Project will now be revisited to refine future exploration targeting, particularly with respect to the chargeable feature that remains untested by this shallow RC drilling programme.

Figure 1: Map showing the location of the IP geophysical survey lines and drill collars and previously reported soil sampling survey. Coordinates in EPSG 26911.

Figure 2: Inversions of the IP geophysical survey data (Left = resistivity, right = chargeability).

Hole	X	Y	Azi/Dip	From (ft)	To (Ft)	Interval (ft)	Au (g/t)	Ag (g/t)
RDRC005	422722	4272332	135/-70	90	95	5	0.12	1.21
				125	130	5	0.11	0.29
RDRC004	422722	4272332	270/-45	240	310	70	0.03	1.64
RDRC001	423093	4272498	200/-60	445	460	15	0.05	1.13

Table 1: Highlight drill hole assay intervals. Coordinates in EPSG 26911.

Additional Information

RC chip samples were logged and collected at 5ft (1.5 m) intervals and submitted to ALS laboratories, Reno, Nevada. Samples were analysed by methods ME-MS61 and Au-AA25. Quality control samples (duplicates, blanks and certified reference materials) were inserted by the Company and results reviewed prior to release. Down hole surveys were completed for every hole.

Qualified Person Statement

The information in this announcement that relates to exploration results is based on information reviewed by Dr Lawrence Carter MSc PhD MAusIMM who is an Independent Geological Consultant. Dr Carter is a "Qualified Person" as defined in the "Note for Mining and Oil & Gas Companies" which form part of the AIM Rules for Companies. Dr Carter has reviewed and consented to the inclusion in the announcement of the information in the form and context in which it appears.

ENDS

For further information visit www.greatwesternmining.com or contact:

Great Western Mining Corporation PLC
Brian Hall, Chairman	c/o St Brides
Max Williams, Finance Director	[e-mail]
Davy
Nominated Adviser, Euronext Growth Adviser & Joint Broker
Brian Garrahy	[phone]
Shard Capital Partners
Joint Broker
Andrew Gutmann / Erik Woolgar	[phone]
St Brides Partners
Financial PR
Susie Geliher / Isabel de Salis / Will Turner	[e-mail]

Notes

Great Western Mining Corporation PLC (AIM: GWMO / Euronext Growth: 8GW) is a diversified exploration and development company focused on strategic minerals across several 100%-owned claim groups in Mineral County, Nevada, one of the world's most prolific and mining-friendly jurisdictions. Backed by an experienced team, the Company is pursuing a multi-commodity strategy targeting near-term development and longer term exploration while assessing farm-out and joint venture opportunities to unlock broader portfolio value. As well as its flagship Huntoon Copper Project, which hosts a JORC-compliant resource of 4.3 Mt at 0.45% Cu, with upside from undrilled porphyry targets, it has a pipeline of gold, silver, and early-stage tungsten assets aligned with US critical minerals priorities.

 

END