Cornish Metals: ROSKEAR EXPLORATION DRILLING UPDATE

Cornish MetalsAnnouncement

01/06/2026 07:00

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ROSKEAR EXPLORATION DRILLING UPDATE

1 June 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 provide an update on the ongoing surface diamond
drilling programme in the Roskear area of the South Crofty mine.

The programme comprises approximately 2,400 metres of 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 has reached its final depth of 1,199.1 metres and has
intersected zones of quartz-tourmaline veining with visible cassiterite,
sulphide mineralisation, and alteration consistent with the target mineralised
system.

Highlights

* Drillhole SDD26_001A completed to a final depth of 1,199.1 metres
* Multiple target mineralised structures intersected, including mineralised
  structures which host existing Mineral Resources
* Mineralised structures intercepted west of current Mineral Resource estimate
  (“MRE”) envelopes, highlighting potential opportunities for resource growth
* Second drillhole, SDD26_002, to commence targeting the same structures
  approximately 100 metres west of SDD26_001A
* Samples currently being prepared for shipment to ALS Laboratories in
  Loughrea, Ireland, with assay results expected in June 2026

Don Turvey, CEO of Cornish Metals commented:

“The completion of drillhole SDD26_001A marks an important milestone in this
targeted exploration drilling programme at South Crofty. The drillhole has
successfully intersected multiple projected mineralised structures, including
extensions to known resource areas beyond the current Mineral Resource
estimate envelopes.

While assay results are still pending, the visual indications of
mineralisation encountered are encouraging and support our geological
interpretation of continued mineralisation to the west of the existing Mineral
Resource areas. This programme is designed not only to assess opportunities
for future Mineral Resource growth, but also to sterilise key infrastructure
areas incorporated within the current mine design. We look forward to
commencing the second hole in the programme and reporting assay results in due
course.”

Figure 1: Quartz chlorite tourmaline veining with visible cassiterite (e.g.
orange circle) associated with tourmaline, as logged by Cornish Metals
geologists.
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Figure 2: Quartz tourmaline vein hosted in granite with a band of cassiterite
mineralization (e.g. indicated by the orange arrows), as logged by Cornish
Metals geologists.
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Figure 3: Chlorite-haematite-quartz structure with disseminated cassiterite
mineralisation throughout (e.g. indicated by the orange arrow), as logged by
Cornish Metals geologists.
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Figure 4: Chlorite alteration with visible coarse cassiterite (e.g. orange
circle), as logged by Cornish Metals geologists.
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Programme Objectives

* Test the western extensions of the Roskear B and Roskear South mineralised
  structures beyond the limits of the current Mineral Resource envelopes
* Intersect projected structures within the Roskear Numbered Zone that are not
  currently included in the South Crofty MRE
* Sterilise granite-hosted areas planned for critical infrastructure
  associated with the Preliminary Economic Assessment mine design, including
  planned ramp development in the Dolcoath and Roskear areas

Programme Update

The completion of drillhole SDD26_001A marks the halfway point of the
two-hole, 2,400 metre drilling programme. SDD26_001A intersected along-strike
interpreted projections of the Roskear 1 South, Roskear South, Roskear 6 North
and Roskear 7 North structures, in addition to the target structures
associated with Roskear B.

Roskear South and Roskear B contain Mineral Resources as reported in the
Company’s 2023 MRE.

The Roskear 1 South, Roskear 6 North and Roskear 7 North lodes form part of a
group of mineralised structures known as the Roskear Numbered Zone. These
structures currently have limited supporting data from historic channel
sampling and drillhole intercepts and are not presently included within the
South Crofty MRE.

Following completion of SDD26_001A, the drill rig will be realigned to
commence drillhole SDD26_002, which is designed to test the same structures
approximately 100 metres west of SDD26_001A. Samples from SDD26_001A are
currently being prepared for shipment to ALS Laboratories in Loughrea,
Ireland, with assay results expected in June 2026.

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 Inc, who is the designated QP for the Company.

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/rLzm0y

For additional information please contact:

+---------------------------+------------------+-----------------------------+
| Cornish Metals            | Fawzi Hanano     | investors@cornishmetals.com |
|                           | Emily Allhusen   | info@cornishmetals.com      |
+---------------------------+------------------+-----------------------------+
|                           |                  | Tel: +44 1209 715 777       |
|                           |                  |                             |
+---------------------------+------------------+-----------------------------+
| SP Angel Corporate        | Charlie Bouverat | Tel: +44 203 470 0470       |
| Finance LLP               | Adam Cowl        |                             |
| (Nominated Adviser)       | Ewan Leggat      |                             |
|                           |                  |                             |
|                           |                  |                             |
+---------------------------+------------------+-----------------------------+
|                           |                  |                             |
|                           |                  |                             |
+---------------------------+------------------+-----------------------------+
| Berenberg                 | Jennifer Lee     | Tel: +44 20 3753 3040       |
| (Joint Broker)            | Ivan Briechle    |                             |
+---------------------------+------------------+-----------------------------+
|                           |                  |                             |
|                           |                  |                             |
| Peel Hunt                 | Ross Allister    | Tel: +44 20 7418 8900       |
| (Joint Broker)            | David McKeown    |                             |
+---------------------------+------------------+-----------------------------+
|                           |                  |                             |
|                           |                  |                             |
+---------------------------+------------------+-----------------------------+
| BlytheRay                 | Tim Blythe       | cornishmetals@blytheray.com |
| (Financial PR)            | Megan Ray        | Tel: +44 207 138 3204       |
|                           | Said Izagaren    |                             |
+---------------------------+------------------+-----------------------------+

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