Announcement PDF RNS Number : 1144Z Great Southern Copper PLC 15 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. 15 October 2026 Great Southern Copper plc (“GSC” or the “Company”) Admission of Shares and Director/PDMR Shareholdings Further to the RNS announcement on 8 October 2026, Great Southern Copper plc (LSE: GSCU), the company focused on copper-gold-silver exploration in Chile, announces the Admission of the 133,333,333 New Shares in the Company to trading on the Main Market of the London Stock Exchange plc, became effective at 8.00am this morning. Details of new shares admitted 133,333,333 new ordinary shares of 1p each, at a price of £0.0150 per ordinary share for gross total proceeds of £2,000,000; Director Participation The Directors of the Company participated in the fundraise and subscribed, in aggregate, for 4,666,667. Details of the subscriptions by Directors are as follows: Name Existing Shareholding % Number of shares subscribed for Shareholding on admission Percentage of issued share capital on admission Charles Bond 8,510,191 1.10% 666,667 9,176,858 1.01% Samuel Garrett 16,305,501 2.11% 3,333,333 19,638,834 2.17% Nicholas Briers 2,311,110 0.30% 666,667 2,977,777 0.33% Total Voting Rights The total number of issued shares and the total number of voting rights in the Company is 906,703,489. 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 Sam Garrett, Chief Executive Officer +44 (0)20 4582 3500 SI Capital Limited Nick Emerson +44 (0)14 8341 3500 Keith Swann BlytheRay Megan Ray / James Mulligan +44 (0) 20 7138 3204 gsc@blytheray.com Notification and public disclosure of transactions by persons discharging managerial responsibilities/ person closely associated with them. 1 Details of the person discharging managerial responsibilities/person closely associated a) Name Charles Bond 2 Reason for the notification a) Position/status Chairman b) Initial notification/ Amendment Initial Notification 3 Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor a) Name Great Southern Copper plc b) LEI 213800RF6N9WA8PZH313 4 Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted a) Description of the financial instrument, type of instrument Identification code Ordinary shares of 1 pence each GB00BLB5BF24 b) Nature of the transaction Shares issued in lieu of salary c) Price(s) and volume(s) Price(s) Volume(s) 1.5p 666,667 e) Date of the transaction 15 October 2026 f) Place of the transaction London Stock Exchange 1 Details of the person discharging managerial responsibilities/person closely associated a) Name Samuel Garrett 2 Reason for the notification a) Position/status Chief Executive Officer b) Initial notification/ Amendment Initial Notification 3 Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor a) Name Great Southern Copper plc b) LEI 213800RF6N9WA8PZH313 4 Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted a) Description of the financial instrument, type of instrument Identification code Ordinary shares of 1 pence each GB00BLB5BF24 b) Nature of the transaction Shares issued in lieu of salary c) Price(s) and volume(s) Price(s) Volume(s) 1.5p 3,333,333 e) Date of the transaction 15 October 2026 f) Place of the transaction London Stock Exchange 1 Details of the person discharging managerial responsibilities/person closely associated a) Name Nicholas Briers 2 Reason for the notification a) Position/status Chief Executive Officer b) Initial notification/ Amendment Initial Notification 3 Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor a) Name Great Southern Copper plc b) LEI 213800RF6N9WA8PZH313 4 Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted a) Description of the financial instrument, type of instrument Identification code Ordinary shares of 1 pence each GB00BLB5BF24 b) Nature of the transaction Shares issued in lieu of salary c) Price(s) and volume(s) Price(s) Volume(s) 1.5p 666,667 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 DSHMABRTMTIBMPF e) Date of the transaction 15 October 2026 f) Place of the transaction London Stock Exchange 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