18 August 2026

GREAT WESTERN MINING CORPORATION PLC

(“Great Western”, “GWM” or the “Company”)

Drilling Programme Commences at Defender Tungsten Project, Nevada

Resource drilling targets tungsten corridor ahead of maiden MRE in Q4 2026

Great Western Mining Corporation PLC (AIM: GWMO / Euronext Growth: 8GW / OTCQB: GWMOF), a strategic minerals exploration and development company, is pleased to announce that drilling has commenced at its Defender Tungsten Project in Mineral County, Nevada, USA (“Defender” or the “Project”).

HIGHLIGHTS

• Drilling underway to test grade an initial 600-1,000 metre corridor encompassing the Pine Crow, Dough God and Defender tungsten mines, collectively components of the Defender Tungsten Project.
• Fully funded and on track to deliver a maiden Mineral Resource Estimate (“MRE”) by the end of 2026, incorporating results from a minimum 7,000 feet (2,135 metre) drilling programme.
• CEO Ed Loye and Lewis Harvey of Addison Mining Services (“Addison”), the independent Competent Person for the maiden JORC MRE, are on site for the start of drilling.
• Drill assay results expected through September and October 2026.
• Q2 2026 bulk sample metallurgical results expected in August 2026.

Great Western CEO, Ed Loye, commented: “It is great to see drilling now underway at Defender following a significant amount of preparatory work. From geophysics and geological mapping through to channel sampling and drill pad construction, a great deal of work has gone into reaching this stage and it is very satisfying to see it all come together.

“Lewis Harvey of Addison and I are both on site for the start of the programme, with Lewis overseeing the logging, sampling, data capture and quality control required for the maiden MRE. Having that oversight in place from the outset will help ensure an efficient transition from drilling through to resource estimation.

“Investors can look forward to a busy period of news flow, with results from the bulk sample metallurgical programme expected in the coming weeks, followed by drill assays through September and October. Taken together, this work keeps us firmly on track to deliver a maiden MRE by the end of 2026.”

DETAILS

The Defender Tungsten Project comprises the historic Widowmaker, Pine Crow, Dough God and Defender tungsten mines, located along a >2km mineralised corridor in Mineral County, Nevada. Great Western’s exploration work to date, including geophysics, geological mapping, trenching and surface sampling, has identified tungsten mineralisation across the Project and provided the basis for a resource drilling programme.

The minimum 7,000 feet (2,135 metre) programme commenced yesterday, 17 August 2026, and will comprise up to 22 drill holes. It is designed to test the continuity and grade of tungsten mineralisation across part of the Defender corridor and generate the geological data required to support a maiden Mineral Resource Estimate (“MRE”).

As announced on 4 August 2026, the Company has engaged Addison Mining Services as the independent Competent Person responsible for the development of the maiden MRE. Lewis Harvey, Director Exploration Services & Principal Geologist of Addison, is on site overseeing core logging, sampling protocols, data capture and quality assurance throughout the drilling programme.

CEO Ed Loye is also on site for the commencement of drilling. Assay results from the programme are anticipated through September and October 2026.

In parallel, the Company is awaiting results from the 750 kg representative metallurgical bulk sample sent to Eriez in Pennsylvania for flotation test work, as announced on 1 June 2026. Results are expected in August 2026.

The Company remains fully funded for its 2026 exploration programme and on target to deliver a maiden MRE by the end of 2026.

ENDS

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

Notes

Great Western Mining Corporation PLC (AIM: GWMO / Euronext Growth: 8GW / OTCQB: GWMOF) 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.