POSITIVE ASSAY RESULTS FROM ROSKEAR DRILLING PROGRAMME

POSITIVE ASSAY RESULTS FROM ROSKEAR DRILLING PROGRAMME

9 July 2026

Cornish Metals plc (AIM: TIN) (“Cornish Metals” or the “Company”), a mineral exploration and development company focused on advancing its wholly owned and permitted South Crofty tin project (“South Crofty”) in Cornwall, United Kingdom, is pleased to announce positive assay results from the first drillhole of the ongoing surface drilling programme in the Roskear area of the South Crofty mine.

The programme comprises approximately 2,400 metres of diamond drilling designed to test extensions to known mineralisation and evaluate several priority exploration targets identified through historic drilling and recent geological interpretation.

Drillhole SDD26_001A, the first of two planned holes, has been completed to a final depth of 1,199.1 metres. Assay results have now been received and returned tin (“Sn”) mineralisation across multiple intercepts, consistent with the Company’s geological interpretation, and including mineralised structures that lie outside the current Mineral Resource Estimate (“MRE”).

Highlights

• Assay results received for drillhole SDD26_001A, the first hole of the two-hole Roskear programme, returning tin mineralisation across multiple intercepts
• High-grade tin intersections returned, including 0.79 metres at 4.18% Sn (Roskear 1 South) and 0.30 metres at 2.20% Sn (Roskear 3 North)
• Broad 12.41 metre zone grading 0.43% Sn intersected in the Roskear Numbered Zone, including 1.90 metres at 1.32% Sn
• The observed grades and structural positions are consistent with the Company’s geological interpretation and provide additional confidence in the continuity of mineralised structures
• Several intercepts, including two previously unmodelled (“unknown”) lodes and the Roskear Numbered Zone structures, lie outside the current MRE, highlighting potential for Mineral Resource growth to the west subject to further drilling
• Second drillhole, SDD26_002, currently being drilled approximately 100 metres west of SDD26_001A and approximately halfway to its planned final depth

Lauren Beveridge, Chief Geologist of South Crofty, commented:

“These are very encouraging results from the first hole of the Roskear programme. SDD26_001A successfully intersected each of the targeted lodes, with grades and positions consistent with our geological interpretation, providing further confidence in our legacy sample dataset and underground survey.

“Just as importantly, several of the intercepts, including two previously unrecorded lodes, sit outside our current MRE, and we can see the mineralisation continuing to the west. Taken together, the results confirm the Roskear area as a high-quality exploration target with clear potential to add to our Mineral Resources. In addition, it provides additional confidence in our assumptions regarding resource replacement across South Crofty, which has the potential to significantly extend the life of mine. Drilling of the second hole is already well advanced, and we look forward to reporting those results in due course.”

Table 1: Significant assay intercepts, drillhole SDD26_001A

Drillhole	From (m)	To (m)	Sample length (m)	Sn Grade (%)	Additional Grades	Cross section reference
SDD26_001	234.30	235.08	0.78	0.55	0.21% Cu and 3.52% Zn	A. Dolcoath Mid
SDD26_001A	635.86	636.32	0.46	1.49		B. Unknown lode
SDD26_001A	655.60	656.60	1.00	0.45		C. Unknown lode
SDD26_001A	691.93	692.72	0.79	4.18		D. Roskear 1 South
SDD26_001A	732.32	735.73	3.41	0.49		E. Roskear South
including	732.32	733.41	1.09	0.74
and	734.38	734.86	0.48	0.29	2.75% Cu
SDD26_001A	803.10	804.28	1.18	0.35		F. Unknown Lode
including	803.93	804.28	0.35	1.16
SDD26_001A	824.34	825.16	0.82	0.83		G. Roskear 3 North
including	824.34	824.64	0.30	2.20
SDD26_001A	849.81	850.47	0.66	0.22	2.01% W	H. Roskear Numbered Lode
SDD26_001A	905.42	917.83	12.41	0.43		I. Roskear Numbered Lode
including	906.64	907.04	1.43	0.81
and	916.87	917.83	1.90	1.32
SDD26_001A	1028.10	1028.82	0.72	1.12		J. Unknown Lode just below planned ramp

Note 1: Composited values use a downhole length weighted average of grade. True intersection widths have not yet been calculated.

Image 1: Cross section looking East of intercepts from drillhole SDD26_001A. Note: Grid annotations are the South Crofty Mine Grid.

Image 2: Core tray image showing section interpreted to be Roskear 1 South lode; strong tourmaline-quartz-chlorite with disseminated cassiterite and well-defined hangingwall and footwall contacts

Image 3: Core tray image showing part of the section interpreted to be Roskear Numbered Zone, which may be two or more individual lodes. Haematite altered granite with haematite-quartz-chlorite veins hosting cassiterite mineralisation

Programme Update

Assay results for drillhole SDD26_001A are summarised in Table 1 above. The drillhole successfully intersected the interpreted along-strike projections of the Roskear 1 South, Roskear South and Roskear Numbered Zone structures at, or close to, their predicted positions. The results provide additional confidence in the Company's geological and structural interpretation and the continuity of mineralisation in this western part of the deposit. Mineralisation was intersected throughout the granite section of the drillhole and remains open to the west, consistent with the Company’s interpretation that the Roskear structures continue beyond the current resource limits. The results confirm the Roskear area as a high-priority exploration target with clear potential to expand mineral resources through the ongoing and future planned drilling programmes.

Drillhole SDD26_002, located approximately 100 metres west of SDD26_001A, is currently being drilled and is approximately halfway to its planned final depth. It is designed to test the same mineralised structures further to the west, with assay results to be reported once received from ALS Laboratories in Loughrea, Ireland.

QAQC

NQ sized diamond core samples have been halved by using a diamond blade core saw, then bagged and secured before transportation to ALS Laboratory in Loughrea, Ireland. For quality assurance (“QA”), coarse blanks, certified reference materials and field duplicates were inserted into the sample sequence, amounting to approximately 15% of the total sample quantity. Samples were assayed using ALS method ME-XRF15b, where samples are analysed by XRF following a lithium borate fusion. ALS Laboratories quality management system includes inter-laboratory test programmes and regularly scheduled internal audits that meet all requirements of ISO/IEC 17025:2017 and ISO 9001:2015.

Qualified Person

This news release has been reviewed and approved by Mr Stephen Holley, (BSc (Hons), ACSM, MSc, MSCM, CEng FIMMM), Technical Services Manager for Cornish Metals plc, who is the designated Qualified Person for the Company and a Qualified Person as defined by the AIM Rules for Companies. Mr Holley consents to the inclusion in this announcement of the technical matters based on his information in the form and context in which it appears.

ABOUT CORNISH METALS

Cornish Metals is a mineral exploration and development company that is advancing the South Crofty critical mineral project towards production. South Crofty:

• is a historical underground tin mine located in Cornwall, United Kingdom and benefits from existing mine infrastructure including multiple shafts that can be used for future operations;
• is the highest grade known tin Mineral Resource not in production with significant near-mine and regional Mineral Resource potential;
• is permitted to commence underground mining (valid to 2071), construct a new processing facility and for all necessary site infrastructure;
• is expected to produce approximately 4,700 tonnes of tin-in-concentrate annually in the first five years of full production at lowest-quartile all-in sustaining costs over an initial 14-year mine life;
• will be a low environmental impact underground mine with zero surface tailings;
• would be potentially the first primary producer of tin in Europe or North America. Tin is a Critical Mineral as defined by the UK, American, and Canadian governments as it is used in almost all electronic devices and electrical infrastructure. Approximately two-thirds of the tin mined today comes from China, Myanmar and Indonesia;
• benefits from strong local community, regional and national government support with a growing team of skilled people, local to Cornwall, and could generate over 300 direct jobs;
• is an opportunity for a secure domestic supply of tin in the UK supporting a low carbon economy.

ENDS

Engage with us directly at our investor hub. Sign up at: https://investors.cornishmetals.com/link/y5XW7P

For additional information please contact:

Cornish Metals	Fawzi Hanano Emily Allhusen	[e-mail] [e-mail]
		Tel: [phone]
SP Angel Corporate Finance LLP (Nominated Adviser)	Charlie Bouverat Adam Cowl Ewan Leggat	Tel: [phone]
Berenberg (Joint Broker)	Jennifer Lee Ivan Briechle	Tel: [phone]
Peel Hunt (Joint Broker)	Ross Allister David McKeown	Tel: [phone]
BlytheRay (Financial PR)	Tim Blythe Megan Ray Said Izagaren	[e-mail] Tel: [phone]

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