Announcement PDF RNS Number : 8243Y Aterian PLC 14 October 2026 14 October 2026 Aterian plc (“Aterian” or the “Company” or the “Group”) Azrar Copper-Silver Project: Field Work Underway Aterian plc (LSE: ATN), the Africa-focused critical metals exploration, development and trading company, is pleased to announce that initial exploration fieldwork at its 85%-owned Azrar Copper-Silver Project (“Azrar” or the “Project”) in Morocco has identified multiple copper showings and substantially expanded the known mineralisation footprint at the Amane Target (“Amane”). The work programme has commenced and is fully funded through the Company’s AI joint venture (“JV”) with Lithosquare SAS (“Lithosquare”). Highlights: JV-funded exploration has commenced at Azrar, initially focusing on the Amane Target. Initial mapping of 4 of 22 planned traverses has identified copper showings over an apparent 1.60 km strike length within the now 2.50 km long Amane Target. New stratabound copper showings have been identified, with mineralised exposures having apparent thicknesses ranging from up to approximately 7m at Amane West and 2m at Amane North. Historic workings associated with visible copper mineralisation have been identified. Access preparation and logistical works have been initiated ahead of anticipated scout drilling in Q4 2026. Hyperspectral data acquisition, processing and drill target-generation are ongoing. Charles Bray, Executive Chairman of Aterian, commented: “The initial mapping results strengthen Azrar’s exploration potential by expanding the known copper mineralisation footprint at Amane and identifying multiple copper showings, including in previously unexplored areas. Mapping of only 4 of the 22 planned traverses has identified copper showings over an apparent 1.60 km strike length within the now 2.50 km long Amane Target. Locally, mineralisation has an apparent thickness of up to seven metres, and recently discovered historic workings appear to have targeted copper mineralisation. These results are highly encouraging, although the continuity and full extent of the mineralisation remain to be determined. Further traverse mapping will seek to extend the mineralised footprint before detailed mapping, sampling and target prioritisation. Access works and detailed mapping are also advancing existing target areas towards drill-ready status, and we are engaging with local drilling contractors ahead of scout drilling in Q4 2026. We look forward to updating shareholders as the current work programme at Azrar progresses.” Initial Amane Observations New mapping has substantially expanded the known footprint of previously discovered mineralisation at the Amane Target. To the north, initial results indicate a strike length potential of 1.00 to 1.20 km; to the west, they indicate an approximate strike length potential of 0.25 km. Apparent thicknesses vary from approximately 1.00 m to 7.00 m, with potential for stacked, cyclical repetitions of mineralisation. The along-strike continuity and extent of the mineralisation remain to be determined. Mineralisation occurs in two geological settings: gently dipping sandstone-conglomerate beds within the Lower Adoudou Formation sedimentary package; and silica-rich and siltstone-rich beds within the massive dark-grey dolomite of the basal dolomitic sediments (Tamjout dolomite) of the Upper Adoudou Formation sedimentary package. At the Tifrit Target, previously undiscovered stratabound copper mineralisation has been identified within basal conglomerate and fine-grained sandstone beds of the Lower Adoudou Formation. The mineralisation occurs over apparent widths of 3.00 m and has been traced laterally over 50 m. The copper mineralisation is characterised by copper carbonate minerals, notably malachite, and minor primary sulphides. The Project will undertake detailed mapping and systematic sampling over priority targets. Lithosquare-funded exploration programme The field programme at Azrar has four principal objectives: 1. Improve access to the priority Amane Target. 2. Undertake detailed mapping and a topographic survey over an initial drill target at Amane to support detailed drill planning. 3. Map approximately 22 traverses, totalling 8.20 line km, across prospective basal Adoudou Formation sediments throughout the Project. 4. Engage with local stakeholders and communities ahead of planning and drilling in Q4 2026. Hyperspectral data acquisition over the Project is also ongoing. The survey results will be integrated with existing datasets to identify, rank and prioritise targets for ground-truthing and mapping. AI-enabled technology will be used to significantly increase the efficiency of drill target ranking. Azrar Project Background Aterian holds an 85% interest in the 76.9 km² Azrar copper-silver project in Morocco’s Western Anti- Atlas. Lithosquare, the Paris-based AI company, holds a 15% interest in the Project. The Azrar project lies approximately 45 km east of Managem Group’s Tizert copper-silver project. Mineralisation at Tizert is not necessarily indicative of mineralisation at Azrar. The presence of neighbouring deposits underscores the district-scale prospectivity of the Anti-Atlas Belt, although mineralisation at those deposits is not necessarily indicative of mineralisation at Agdz and Azrar. Illustrations The following figures/images have been prepared by Aterian and relate to the disclosures in this announcement. 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, CEO & 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 / Devik Mehta Tel: +44 20 3470 0470 Financial PR: Bald Voodoo - ben@baldvoodoo.com Ben Kilbey Tel: +44 (0)7811 209 344 Subscribe to our news alert service: https://atn-l.investorhub.com/auth/signup 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: “Ag” means silver “Anti-Atlas Mountains” means a mountain range in Morocco, forming part of the Atlas Mountains in northwest Africa. The Anti-Atlas extends from the Atlantic Ocean in the southwest towards the northeast to the heights of Ouarzazate and further east to the city of Tafilalt, a distance of approximately 500 km. The range borders on the Sahara to the south “Au” means Gold “Breccia” means a rock consisting of angular fragments of stones cemented by finer materials “Cambrian” means the first geological period (538 to 485 Ma) of the Paleozoic Era “Cu” means copper “Ediacaran” means the uppermost division of the Proterozoic Eon of Precambrian time and the youngest period (635 to 538 Ma) of three that make up the Neoproterozoic Era “Ferruginous” means containing iron oxides “Float sample” means loose pieces of rock that are not connected to an outcrop “g/t” means grams per tonne “Hercynian or Variscan Orogeny” means an orogenic belt that evolved during the Devonian and Carboniferous periods, from about 419 to 299 million years ago “Inlier” means an area of older rocks surrounded by younger rocks. The erosion of overlying younger rocks typically forms inliers. “km” means kilometres “m” means metres “Ma” means million years “mm” means millimetres “Mt” means millions of tonnes “Outcrop” means a rock formation that is in situ and visible on the surface “Qualified Person” means a person who has the education, skills and professional credentials to act as a qualified person under NI 43-101 “Paleoproterozoic” means the first of three subdivisions of the Proterozoic Eon (occurring from 2,500 Ma to 1,600 Ma. This period is marked by the first stabilisation of the continents and when cyanobacteria evolved. “Sedimentary-hosted copper” means stratabound copper deposits that are typically restricted to a narrow range of layers within a sedimentary sequence but do not necessarily follow sedimentary bedding. “Stratabound” means a mineral deposit confined to a single stratigraphic unit “Stratiform” means parallel to the bedding planes of the surrounding rock “Vein” means a distinct sheetlike body of crystallised minerals within a rock This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact rns@lseg.com or visit www.rns.com. 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