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

1 June 2026

GREAT WESTERN MINING CORPORATION PLC

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

Tungsten Exploration Update

Advancing Exploration Across the Defender-M2 Mineralised Corridor in Nevada

Great Western Mining Corporation PLC, the exploration and development company focused on mineral projects in Nevada, USA, is pleased to provide an operational update on exploration activities at the Defender-Pine Crow Tungsten Project ("Defender-Pine Crow" or the "Project") in Mineral County, Nevada, USA.

OVERVIEW

·    Initial exploration work programmes have been completed across the 3 km corridor between Defender-Pine Crow and the existing M2 copper resource.

·    Programmes designed to support the planned July 2026 drilling campaign and assess the broader extent of tungsten mineralisation within the Black Mountain claim area.

·    Gravity geophysical survey completed by Zonge International covering approximately 3 km by 500 m.

·    Geological mapping of skarn occurrences completed, and new grab samples submitted for assay, identifying additional prospective zones and structural controls.

·    Drill pad locations selected for upcoming drilling and access roads between the historic workings known as the Dough God Mine, located approximately 500m south-west of Defender, and the Defender Mine submitted to the Bureau of Land Management ("BLM") for permitting approval.

·    Four new machine-cut trenches completed, with all samples submitted for assay:

o  Three trenches located between Defender and Pine Crow Mine.

o  One trench completed at the historic workings known as the Widowmaker Mine, located 2 km west of Defender along strike and midway between Pine Crow Mine and the M2 copper resource.

Great Western CEO, Ed Loye, commented: "The completion of these programmes marks another important step in accelerating the Defender-Pine Crow tungsten project towards drilling and resource definition. In particular, the scale of the geophysical and geological work completed across the broader mineralised corridor is helping us better understand the continuity and district-scale potential of the tungsten system.

"The addition of trenching at the historic workings known as the Widowmaker Mine is especially encouraging as it extends exploration activity further west along strike towards M2, supporting our view that this is part of a much larger mineralised trend.

"With drilling scheduled to commence in July, we now look forward to the next phase of work and to receiving the assay and metallurgical results in due course."

DETAILS

The Company is undertaking a fully funded 2026 exploration programme to deliver an initial maiden resource estimate for Defender-Pine Crow tungsten project by end of Q4. The current work programme is designed both to support the planned drilling campaign commencing in July 2026 and to further assess the scale, continuity and geometry of tungsten mineralisation within the broader Black Mountain claim area.

As part of this work, Zonge International has completed a detailed gravity geophysical survey covering approximately 3 km by 500 m across the corridor. The survey data will be integrated with recent geological mapping and grab sampling as an additional vector to better understand the skarn and tungsten mineralisation in the Defender to M2 corridor.

Preparatory work for drilling is also advancing, with proposed drill pad locations and access roads between the Dough God Mine and Defender Mine now selected and submitted to the BLM for permitting approval.

Additionally, four new machine-cut trenches have been completed across the project area. Three pre-existing trenches and outcrops were machine cut between the Defender and Pine Crow Mines, while a fourth was completed at the Widowmaker Mine, located approximately 2 km west of Defender along strike and midway between Pine Crow and the M2 copper resource. Samples from all trenches have been submitted for assay, with results expected in due course.

As previously reported, the Company has also sent a 750 kg representative metallurgical bulk sample to Eriez in Pennsylvania for flotation test work to support future development studies.

ENDS

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

Notes

Great Western Mining Corporation PLC (AIM: GWMO / Euronext Growth: 8GW) is an exploration and development company focused on strategic minerals across several 100%-owned claim groups in Mineral County, Nevada, a highly prospective and mining-friendly jurisdiction. The Company has an increasing strategic emphasis on tungsten as a critical mineral, while continuing to advance its Huntoon Copper Project, which hosts a JORC-compliant resource of 4.3 Mt at 0.45% Cu with further porphyry upside. It also maintains exposure to gold and silver through exploration and tailings reprocessing opportunities, alongside evaluating farm-out and joint venture options to unlock wider portfolio value.

Forward‑Looking Statements

This announcement contains forward‑looking statements relating to the plans, activities and expectations of Great Western Mining Corporation PLC. Such statements include, but are not limited to, those concerning planned exploration programmes, anticipated timelines and potential mineral resource outcomes. Forward‑looking statements are typically identified by words such as "plan", "expect", "anticipate", "intend", "may", "could", "potential" or similar expressions.

These statements are based on current expectations and assumptions and involve risks and uncertainties that could cause actual results to differ materially. Factors include geological risk, exploration and drilling results, permitting and regulatory approvals, funding availability, operational challenges, commodity price movements and general market conditions. No assurance can be given that any forward‑looking statements will prove to be accurate, and shareholders are cautioned not to place undue reliance on them.