Tertiary Minerals Regulatory News (TYM)

10 August 2023

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Tertiary Minerals plc

("Tertiary" or "the Company")

Exploration Update - Zambia - Soil Sampling Programme Commences

Following the receipt of forest permits announced on 31 July 2023, Tertiary Minerals plc (AIM: TYM), is pleased to announce the start of soil sampling and to provide the following update on its Zambian copper exploration projects.

Key Point Summary:

Konkola West Project

· Interpretation of airborne geophysical data provided by KoBold Metals has now identified areas in the north and northwest of the licence where the target Lower Roan formation - the main host to copper mineralisation on the Zambian Copperbelt - may be shallower and less steeply dipping than on the eastern side of the licence.

· Soil sampling is now underway to explore higher up in the sequence with approximately 260 soil samples due to be collected over the next few days. Soil samples will be analysed in the field using a portable XRF ("pXRF") analyser and follow up infill sampling will be carried out as appropriate.

· Konkola West lies immediately west of the Konkola-Lubambe-Musoshi copper mining licences and potentially contains downdip extensions of the laterally continuous Lower Roan ore shale horizon on the east side of the licence.

Mukai Project

· Soil sampling will commence at Mukai immediately after completion of work at Konkola West.

· Mukai adjoins First Quantum Minerals' ("FQM") Trident Project licences which include the large Sentinel copper mine and the recently opened Enterprise nickel mine.

· Approximately 310 soil samples will be collected on a 300m x 100m grid with additional infill sampling to test a historic soil anomaly in favourable stratigraphy along strike of FQM's Tirosa Prospect where FQM has drilled up to its licence boundary with Mukai.

Mushima North Project

· Mushima North is located east of the high grade Kalengwa Copper Mine and numerous targets have been identified for both iron-oxide-copper-gold ("IOCG") mineralisation and conventional Copperbelt style mineralisation.

· Soil sampling at Mushima North is currently scheduled to follow on from that at Mukai. Approximately 1,150 samples will be collected on 200 x 200m grids in three main target areas.

Lubuila Project

· Further to the announcement of 17 May 2023 the Company has now completed check analysis of soil samples collected earlier in the field season at Lubuila as well as an evaluation of multi-element geochemistry.

· Copper results have confirmed the previously reported anomalous copper results from Area C. However, the interpretation of multi-element analytical results suggests that the anomalous results are likely the result of lateritic enrichment rather than indicative of significant in-situ copper mineralisation.

Commenting today, Executive Director Patrick Cheetham said:

"Our strategy remains unchanged. Following the completion of these soil sampling programmes we will be in a position to prioritise areas for follow up drilling alongside the Jacks Copper Project where we completed extensive soil sampling at the end of the 2022 field season and a preliminary drill programme."

"We believe that our licence portfolio in Zambia is amongst the most prospective held by any listed junior explorer in Zambia and our data-sharing and technical cooperation agreement with FQM on the Mukai and Mushima North Projects is an additional differentiator. Despite this we trade at a significant discount to those peers. Now that we have received the necessary permits and work is once again underway, we expect to see an increase in news flow and look forward to updating shareholders with our progress."

Further information on the projects discussed in this news release can be found on the Company website www.tertiaryminerals.com

Separate project presentations can also be found on the Company website for each of the Konkola West, Mukai and Mushima North Copper Projects.

For more information please contact:

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.

Notes

1. A pXRF or portable X-ray fluorescence analyser is a hand-held instrument which provides multi‑element analytical results outside of a laboratory setting. XRF analysis operates by bombarding the sample with X-rays which induces the emission of secondary X-rays exhibiting the energy characteristics of the constituent elements within the sample. pXRF analysers provide real-time analysis and allows immediate follow-up sampling therefore increasing productivity and reducing cost associated with additional mobilisation. pXRF analysers cannot be used as a direct replacement for traditional laboratory-based analysis as the sample is not subjected to rigorous sample preparation and is therefore considered indicative.

2. The information in this release has been compiled and reviewed by Mr. Patrick Cheetham (MIMMM, MAusIMM) who is a qualified person for the purposes of the AIM Note for Mining and Oil & Gas Companies. Mr. Cheetham is a Member of the Institute of Materials, Minerals & Mining and also a member of the Australasian Institute of Mining & Metallurgy.

3. The news release may contain certain statements and expressions of belief, expectation or opinion which are forward looking statements, and which relate, inter alia, to the Company's proposed strategy, plans and objectives or to the expectations or intentions of the Company's directors. Such forward-looking statements involve known and unknown risks, uncertainties, and other important factors beyond the control of the Company that could cause the actual performance or achievements of the Company to be materially different from such forward-looking statements. Accordingly, you should not rely on any forward-looking statements and save as required by the AIM Rules for Companies or by law, the Company does not accept any obligation to disseminate any updates or revisions to such forward-looking statements.