13 May 2026

East Star Resources Plc

("East Star" or the "Company")

Director Appointment

Endeavour Mining Executive VP, Exploration Joins East Star Board

East Star Resources Plc (LSE: EST), the Kazakhstan-focused gold and copper explorer, is pleased to announce the appointment of Sonia Scarselli as a Director of the Company with immediate effect. Ms Scarselli has been appointed as a director representative of Endeavour Mining PLC (LSE: EDV/TSX: EDV) ("Endeavour") following Endeavour's strategic investment in East Star (announced on 1 December 2025) which resulted in Endeavour owning 14.3% of the Company.

Ms Scarselli joined Endeavour, one of the world's leading gold producers and a constituent of the FTSE 100 Index, in 2025 as Executive Vice President, Exploration.

Prior to Endeavour, Ms Scarselli was VP of BHP Exploration and founded BHP's Xplor programme (East Star: 2024 cohort) in 2022. Ms Scarselli started her career at ExxonMobil UK and later joined BHP in 2012, holding several leadership positions including VP of Petroleum Exploration and Appraisals, Head of Algeria, and Exploration Manager for Trinidad and Tobago.

Ms Scarselli holds a master's degree in Geological Science from Università degli studi di Perugia, a PhD in Geology from ETH Zurich, and an MBA from the London Business School. She was appointed a Director of Koulou Gold Corp. in March 2026.

In November 2025, East Star and Endeavour formed a strategic joint venture agreement for gold exploration in Kazakhstan, followed in November 2025 by Endeavour's £1.8 million strategic investment in East Star.

Alex Walker, CEO of East Star Resources, Commented:

"As a member of the 2024 BHP Xplor programme, we had the privilege of working with Sonia and her team and experienced first-hand the benefit of her considerable exploration experience and tactical application of good geoscience. Her strategic thinking will be a significant benefit to East Star and so we are delighted to welcome Sonia to East Star's Board as the representative of our largest shareholder, Endeavour. We look forward to working with Sonia as we advance gold and copper work programmes in Kazakhstan at various stages of the exploration cycle."

East Star Resources Plc

Alex Walker, Chief Executive Officer

Tel: +44 (0)20 7390 0234 (via Vigo Consulting)

SI Capital (Corporate Broker)

Nick Emerson

Tel: +44 (0)1483 413 500

Vigo Consulting (Investor Relations)

Ben Simons / Seb Weller

Tel: +44 (0)20 7390 0234

About East Star Resources Plc

East Star Resources is focused on the discovery and development of copper and gold in Kazakhstan. The Company is pursuing multiple exploration strategies including:

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www.eaststarplc.com 

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About Endeavour Mining PLC

Endeavour Mining is one of the world's senior gold producers and the largest in West Africa, with operating assets across Senegal, Côte d'Ivoire and Burkina Faso and a strong portfolio of advanced development projects and exploration assets.

 A member of the World Gold Council, Endeavour is committed to the principles of responsible mining and delivering meaningful value to people and society. Endeavour is admitted to listing and to trading on the London Stock Exchange and the Toronto Stock Exchange, under the symbol EDV.

The person who arranged for the release of this announcement was Alex Walker, CEO of the Company.

This announcement contains inside information for the purposes of Article 7 of Regulation 2014/596/EU which is part of domestic UK law pursuant to the Market Abuse (Amendment) (EU Exit) Regulations (SI 2019/310) ("UK MAR"). Upon the publication of this announcement, this inside information (as defined in UK MAR) is now considered to be in the public domain.