Announcement PDF RNS Number : 2215A Great Southern Copper PLC 23 October 2026 THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION AS STIPULATED UNDER THE UK VERSION OF THE MARKET ABUSE REGULATION NO 596/2014 WHICH IS PART OF ENGLISH LAW BY VIRTUE OF THE EUROPEAN (WITHDRAWAL) ACT 2018, AS AMENDED. ON PUBLICATION OF THIS ANNOUNCEMENT VIA A REGULATORY INFORMATION SERVICE, THIS INFORMATION IS CONSIDERED TO BE IN THE PUBLIC DOMAIN. 23 October 2026 Great Southern Copper plc (“GSC” or the “Company”) Admission of Shares Further to the release on the 19 October 2026, Great Southern Copper plc (LSE: GSCU), the company focused on copper-gold-silver exploration in Chile, announces the Admission of the 599,595 new Ordinary Shares in the Company to trading on the Main Market of the London Stock Exchange plc, became effective at 8.00am this morning. Total Voting Rights Following Admission, the total number of issued shares and the total number of voting rights in the Company is 907,303,084. The above figure should be used by shareholders in the Company as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, the share capital of the Company under the Financial Conduct Authority's Disclosure Guidance and Transparency Rules. Engage with the GSC management team directly by asking questions, watching video summaries and seeing what other shareholders have to say. Navigate to our Interactive Investor hub here: https://gscplc.com/ Enquiries: Great Southern Copper plc https://gscplc.com/link/yVdAqr Sam Garrett, Chief Executive Officer +44 (0) 20 7138 3204 SI Capital Limited Nick Emerson +44 (0) 1483 413500 BlytheRay Tim Blythe / Megan Ray +44 (0) 20 7138 3204 GSC@blytheray.com Subscribe to our news alert service: https://gscplc.com/auth/signup Notes for Editors: 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. RNS may use your IP address to confirm compliance with the terms and conditions, to analyse how you engage with the information contained in this communication, and to share such analysis on an anonymised basis with others as part of our commercial services. For further information about how RNS and the London Stock Exchange use the personal data you provide us, please see our Privacy Policy. END ADMMJBRTMTTTMLF About Great Southern Copper Great Southern Copper PLC is a UK-listed mineral exploration company focused on the discovery of copper-gold-silver deposits in Chile. The Company has the option to acquire mining rights to 100% of Especularita project in the under- explored coastal belt of Chile that is prospective for large scale copper-gold-silver deposits. Chile is a globally significant mining jurisdiction being the world’s largest producer and exporter of copper. The Especularita Project is located in the coastal metallogenic belt of Chile which hosts significant copper mines and deposits, including Teck’s Carmen de Andacollo copper mine, and boasts excellent access to infrastructure such as roads, power and ports. Significant historical small-scale and artisanal workings for both copper and gold are readily evident in the exploration project area. The coastal belt offers deposit type optionality for copper including porphyry and IOCG style deposits as well as newly recognised intrusive-related copper and gold deposits. Great Southern Copper is strategically positioned to support the global market for copper – a critical battery metal in the clean energy transition around the world. The Company is actively engaged in exploration and evaluation work programmes targeting both large tonnage, low to medium grade Cu-Au as well as high-grade Cu-Ag-Au deposits. Further information on the Company is available on the Company’s website: https://gscplc.com