NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION IN WHOLE OR IN PART IN, INTO OR FROM THE UNITED STATES OR ANY JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OR REGULATIONS OF THAT JURISDICTION.

8^th Floor, 54 Jermyn Street, London, SW1Y 6LX. United Kingdom

Telephone: + 44 (0)20 7629 7772  Facsimile:  + 44 (0)20 7629 7773

E mail: griffin@griffinmining.com

22^nd September 2025

Share Buyback via Reverse Accelerated Bookbuild

On 19 September 2025, Griffin Mining Ltd ("Griffin" or "the Company") announced a share buyback via a reverse accelerated bookbuild (the "RABB Buyback"). The RABB Buyback remains ongoing with details set out in this announcement and the Company's announcement on 19 September 2025.

The Company has engaged Panmure Liberum Ltd ("Panmure Liberum") to implement the RABB Buyback. Pursuant to the RABB Buyback, Panmure Liberum will purchase, as principal, up to a maximum of 10 million Ordinary Shares (being 5.4 per cent. of the Company's Ordinary Shares) at a price per Ordinary Share to be determined based on the offers received in the Buyback process (the "Purchase Price"). The board has authorised the application of no more than $20 million to execution of the RABB Buyback.

The RABB Buyback is expected to close at 16:35 (BST) on 22^nd September 2025 (or other such time as the Company and Panmure Liberum agree). The final number of Ordinary Shares to be purchased, together with the Purchase Price will be agreed at the close of the RABB Buyback at the sole discretion of Griffin and Panmure Liberum, and the results of the RABB Buyback will be announced as soon as practicable thereafter. To the extent that the RABB Buyback is oversubscribed, orders will be scaled back (whether on a pro rata basis or otherwise) at the sole discretion of Griffin and Panmure Liberum.

CREST Shareholders wishing to sell Ordinary Shares as part of the RABB Buyback should inform their broker to contact Panmure Liberum before 16:35 (BST) on 22^nd September 2025. Panmure Liberum: +44 (0)20 7886 2500.

For logistical reasons, the RABB Buyback is not being made available to shareholders who hold their Ordinary Shares in certificated form. However, such shareholders will still be able to offer their Ordinary Shares for purchase by the Company pursuant to the Existing Buy Back Programme which will continue to operate notwithstanding the RABB Buyback. Any purchases of Ordinary Shares under the Existing Buy Back Programme will be carried out on the London Stock Exchange and will continue to be effected within the safe harbour provisions set out in the Market Abuse Regulation 596/2014 ("MAR"), the Commission Delegated Regulation (EU) 2016/1052 and the applicable laws and regulations of the London Stock Exchange.

Purchase of the Company's Ordinary Shares pursuant to the RABB Buyback will take place following announcement of the result of the RABB Buyback.

The primary purpose of the RABB Buyback is to reduce the share capital of the Company. The Ordinary Shares purchased under the RABB Buyback will be cancelled.

The directors of the Company consider the RABB Buyback to be in the best interests of the Company and of its shareholders generally, with the implementation of the RABB Buyback expected to enhance earnings per share.

Any purchase of Ordinary Shares under the RABB Buyback will be carried out on the London Stock Exchange and shall take place in accordance with the Company's existing general authority to repurchase Ordinary Shares.

The person responsible for arranging the release of this announcement on behalf of the Company is

Roger Goodwin, Finance Director.

Enquiries:

Important Notices

The information contained within this Announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulations (Regulation 596/2014) as it forms part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018. Upon the publication of this Announcement via a Regulatory Information Service, this inside information is now considered to be in the public domain.

Panmure Liberum Limited ("Panmure Liberum"), which is authorised and regulated in the United Kingdom by the FCA, is acting as nominated adviser and broker exclusively for Griffin and no one else in connection with the matters set out in this announcement and will not regard any other person as its client in relation to the matters set out in this announcement and will not be responsible to anyone other than Griffin for providing the protections afforded to clients of Panmure Liberum, nor for providing advice in relation to the contents of this announcement or any other matter referred to herein. Neither Panmure Liberum nor any of its subsidiaries, branches or affiliates owes or accepts any duty, liability or responsibility whatsoever (whether direct or indirect, whether in contract, in tort, under statute or otherwise) to any person who is not a client of Panmure Liberum in connection with this announcement, any statement contained herein or otherwise or any transaction, arrangement or other matter referred to herein.

Neither Panmure Liberum, Berenberg,  nor any of its affiliates nor any of their respective directors, officers, employees, advisers or agents accepts any responsibility or liability whatsoever for, or makes any representation or warranty, express or implied, as to, the truth, accuracy or completeness of the information in this announcement (or whether any information has been omitted from the announcement) or any other information relating to Griffin, whether written, oral or in a visual or electronic form, and howsoever transmitted or made available or for any loss howsoever arising from any use of this announcement or its contents or otherwise arising in connection therewith.

All times referred to are London, UK, time unless otherwise stated.