Multiple Copper-Silver Mineralised Structures Identified, Agdz Est Project, Morocco

Aterian plc (AIM: ATN), the Africa-focused critical metals exploration company, is pleased to announce encouraging surface sampling results from its 100%-owned Agdz Est Copper-Silver ("Cu-Ag") Project ("Agdz Est" or the "Project") in the Kingdom of Morocco ("Morocco").

The results identify multiple mineralised fault zones hosting copper and silver, significantly extending the known footprint of mineralisation within the broader 50.4 km² Agdz Project ("Agdz") area. The identification of these multiple mineralised structures over a limited area highlights the potential scale of the system and materially enhances the Company's confidence in advancing Agdz towards drill evaluation.

Highlights:

• Multiple copper-silver mineralised fault zones identified, confirming a structurally controlled mineral system.
• Mineralisation confirmed from only c.10% of the Agdz Est Project, highlighting significant exploration upside.
• Four sub-parallel structures mapped over strike lengths of up to 0.9 km, with apparent widths of up to 7 metres, and open along strike.
• Mineralised zones are spaced 300 to 400m apart, and commonly covered with a thin soil and rock float.
• Encouraging copper and silver grades returned from early-stage surface sampling, including:
  • 1.39 % Cu from a 2 m wide breccia zone
  • 0.51 % Cu with 7 g/t Ag from a 3 x 2 m outcrop of silicified granite
  • 2.97 % Cu with 51 g/t Ag from float sample
  • 1.34 % Cu with 31 g/t Ag from a fractured zone of 4 m apparent width within granite
• Follow-up ground magnetic and trenching planned to test continuity, scale and structural controls on mineralisation.

Strategic Significance

These results support the interpretation that Agdz Est forms part of a broader, district-scale copper-silver system, with multiple mineralised structures developed within a favourable geological setting.

With mineralisation confirmed to date over a limited area, the Company believes there is clear potential to identify additional mineralised structures across the remainder of the permit.

The data generated from this programme will feed into Aterian's previously announced partnership with Lithosquare, the AI-based exploration platform. The data will be used to assist in evaluating Agdz alongside other assets for selection and accelerate decision-making for advanced exploration and drilling. This approach supports a disciplined, technology-enabled framework for prioritising projects with the greatest potential for scalable copper-silver development.

Charles Bray, Chairman of Aterian, commented:

"These early-stage results from Agdz Est represent a highly encouraging breakthrough in unlocking the scale potential of the Agdz Copper-Silver Project. The identification of multiple copper and silver-bearing fault zones, all of which remain open along strike, materially strengthens our strong conviction that Agdz hosts a large, structurally extensive mineral system with meaningful exploration upside.

Importantly, mineralisation has been confirmed across only a small portion of the permit area to date, highlighting the significant untapped potential that remains. The next phase of work will focus on systematic follow-up, including ground geophysics and trenching, designed to define continuity, expand scale, and prioritise high-quality drill targets. We look forward to sharing this new data with our AI partners, Lithosquare.

We are particularly excited by the prospect of advancing towards a focused drilling campaign in Morocco, with Agdz emerging as a flagship opportunity within the portfolio. The growing body of geological evidence continues to reinforce our belief that Agdz has the potential to develop into a substantial copper-silver system. We look forward to delivering further updates as exploration momentum builds and value is progressively unlocked for shareholders."

Project Summary:

The Company, through its wholly owned subsidiary Aterian Resources Limited, holds a 100% interest in the 50.4 km² Agdz Copper-Silver Project, comprising the 15.9 km² Agdz Est licence and the adjacent 34.5 km² Agdz licence in central Morocco. The Project is located in the highly prospective Anti-Atlas Mountains within the Souss-Massa-Drâa region, approximately 35 km east of Ouarzazate, a well-serviced regional hub with an airport and established infrastructure. The Project benefits from excellent access via paved and unpaved roads. It is situated approximately 40 km southeast of the Noor 1 solar power complex, one of the world's largest renewable energy facilities.

Agdz is located within Morocco's highly prospective Anti-Atlas belt, a stable and well-established mining jurisdiction with growing strategic importance for copper supply.

The Agdz Project is situated within a well-established copper-silver mining district, approximately 14 km southwest of the Bouskour copper-silver mine (53 Mt at 0.8% Cu and 9 g/t Ag) and within trucking distance of existing mining infrastructure. The world-class Imiter silver mine (131 Moz at 500 g/t Ag) lies approximately 80 km northeast of the Project, with both operations owned by Managem Group, Morocco's leading mining company. While mineralisation at neighbouring deposits is not necessarily indicative of mineralisation at Agdz, their presence underscores the district-scale prospectivity of the region.

Aterian Sampling Programme

Sampling to date has consisted of 34 surface rock samples: 32 composite point rock chip samples and 2 grab samples from float. The programme aimed to ground-truth remote-sensing data-based interpreted lineaments by completing mapping traverses and tracing faults along strike.

Sampling Methodology and Analysis

Afrilab, an accredited independent laboratory in Marrakech, Morocco, prepared and analysed 108 samples. Rock samples were crushed with 70 % passing -2 mm. The <2 mm fraction was pulverised, with 85 % of the sample passing <75 microns. All samples were analysed for a multi-element suite of 40 elements by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). In addition, selective samples were analysed for their gold content using a 50 g Fire Assay method with a gravimetric finish. Given the early-stage, reconnaissance nature of this programme, QA/QC procedures will be implemented in subsequent phases of work.

Illustrations
The following figures/images have been prepared by Aterian and relate to the disclosures in this announcement.

Work Plan for the Agdz Est Permit

• Completion of an initial ground magnetic survey (32 line km across 3.16 km²) to delineate subsurface structural trends
• Targeted trenching to assess strike continuity, widths and grade distribution
• Ongoing mapping to identify additional priority targets across the Agdz Est permit

Qualified Person

The technical disclosure in this regulatory announcement has been approved by Simon Rollason, Chief Executive Officer of Aterian Plc. A graduate of the University of the Witwatersrand in Geology (Hons). He is a Member of the Institute of Materials, Minerals and Mining, with over 30 years of experience in mineral exploration and mining.

- ENDS -

This announcement contains information which, prior to its disclosure, was inside information as stipulated under Regulation 11 of the Market Abuse (Amendment) (EU Exit) Regulations 2019/310 (as amended).

Engage directly with the Aterian PLC management team by asking questions, watching video summaries, and seeing what other shareholders have to say. Please navigate to our interactive investor hub here: https://aterianplc.com/s/fcf8eb

For further information, please visit the Company's website: www.aterianplc.com or contact:

Aterian Plc:
Charles Bray, Executive Chairman - charles.bray@aterianplc.com
Simon Rollason, Director - simon.rollason@aterianplc.com

Financial Adviser and Joint Broker:
AlbR Capital Limited
David Coffman / Dan Harris
Tel: +44 (0)207 7469 0930

Joint Broker:
SP Angel Corporate Finance LLP
Ewan Leggat / Adam Cowl
Tel: +44 20 3470 0470

Financial PR:
Bald Voodoo - ben@baldvoodoo.com
Ben Kilbey
Tel: +44 (0)7811 209 344

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Notes to Editors:

About Aterian plc

www.aterianplc.com

Aterian plc is an LSE-listed exploration and development company with a diversified African portfolio of critical metals projects.

Aterian plc is actively seeking to acquire and develop new critical metal resources to strengthen its existing asset base while supporting ethical and sustainable supply chains as the world transitions to a sustainable, renewable future. The supply of these metals is vital for developing the renewable energy, automotive, and electronic manufacturing sectors, which are increasingly important in reducing carbon emissions and meeting global climate ambitions.

Aterian has a portfolio of multiple copper-silver (+ gold) and base metal projects in Morocco. Aterian holds a 90% interest in Atlantis Metals, a private Botswana-registered company holding eleven mineral prospecting licences for copper-silver in the world-renowned Kalahari Copperbelt and three for lithium and salt brine exploration in the Makgadikgadi Pans region. The Company also holds an exploration licence in southern Rwanda, where it is evaluating the tantalum and niobium opportunity, in addition to further exploring for pegmatite-hosted lithium.

The Company's strategy is to seek new exploration and production opportunities across the African continent and to develop new sources of critical mineral assets for exploration, development, and trading.

Glossary of Terms

The following is a glossary of technical terms:

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