Operational Update - Zambia

20 December 2024

Tertiary Minerals plc ("Tertiary" or the "Company")

Operational Update - Zambia

The Company wishes to provide the following update, ahead of the Christmas break, on its ongoing drilling programmes in Zambia.

At the Konkola West Copper Project, where KoBold Metals ("KoBold") has the right to earn an equity interest, drilling continued up to 16 December 2024 and is now on hold for the Christmas and New Year holiday. The drill hole has not yet reached the target horizon and KoBold has advised that drilling will resume on or around 7 January 2025 and will continue during the Zambian rainy season.

At the Mukai Copper Project, where First Quantum Minerals Limited ("First Quantum") has the right to earn an equity interest and is funding exploration, First Quantum was able to complete three diamond drill holes for a total of 552m of drilling prior to the onset of the rainy season.

Drill core samples are being submitted for geochemical analysis and the data collected in this short programme will be fed back into the geological model for the project and inform the exploration programme for 2025.

First Quantum has advised that drilling is provisionally planned to resume in the second quarter of 2025, after the end of the rainy season, subject to a review of analytical results and the updating of the geological model.

At the Mushima North Copper Project, a magnetic survey has been completed over the A1 target where positive drill results were reported on 28 October 2024. Interpretation of the magnetic results is providing additional geological context for the reported results and check samples are now in South Africa for geochemical analysis with results anticipated in January 2025. Detailed logging of drill samples is nearing completion and additional drilling is planned to take place in 2025.

An update on the Company's Brunton Pass Copper-Gold Project in Nevada, USA, was made earlier this week, on 16 December 2024.

Commenting today, Executive Chairman, Patrick Cheetham, said:

"It has been gratifying to report on drilling programmes at four different projects in this last quarter of 2025 and to be working with two significant industry players who have already committed substantial funds to our Mukai and Konkola West Projects.

"We are looking forward to progressing these projects and continuing to work with our joint venture partners in 2025."

Further Information:

Market Abuse Regulation

The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014 as it forms part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018 ('MAR'). Upon the publication of this announcement via Regulatory Information Service ('RIS'), this inside information is now considered to be in the public domain.