Zinnwald Lithium plc announced the publication of an updated independent Mineral Resource Estimate ("MRE") for its 100% owned Zinnwald lithium project ("Zinnwald" or the "Project") located in Saxony, eastern Germany. The 2024 MRE update incorporates 26,911 metres of new diamond core drilling across 84 drill holes and a reinterpreted and updated geological model since the previous MRE which was released in September 2018. In addition to the high-grade greisen mineralisation, focus of the recent 2022/2023 drilling was the lithium mineralisation hosted by the broader zone of altered albite granite, which includes internal lenses of higher-grade greisen.

The inclusion of this mineralised zone allows for a higher production rate and a potential optimisation of overall project economics. 2024 Resource Highlights: A 445 % increase in tonnes and a 243% increase in contained lithium ("Li") in the Measured and Indicated category versus the previous 2018 MRE. Total contained Li of 429kt compared with the 2018 MRE of 125kt in the Measured and Indicated category. 11.3 Mt grading 3,420ppm Li (0.736% Li2O) in the Measured category.

193.5 Mt grading 2,220ppm Li (0.478% Li2O) in the Measured and Indicated category. 33.3 Mt grading 2,140 ppm Li (0.461% Li2O) in the Inferred category. Increase in overall tonnage predominantly due to the incorporation of a broad zone of mineralised granite, as well as contribution of an extra 26,911 metres of new drilling over 84 holes.

Measured classification only applied to the external greisen domains due to a higher metallurgical confidence; Snowden Optiro recommends further metallurgical variability testwork in the broad mineralisation zone domain to further increase confidence. Demonstrated dimensions of the mineralised zone (true thickness c. 80 metres) and continuity of ore supports highly efficient mining methods with minimal waste rock production. Mineral Resources reported using a 1,100ppm Li cutoff grade and a stope optimisation to constrain an RPEEE Resource.

Mineral Resource Estimate: Zinnwald Lithium has recently completed an infill drilling campaign in order to increase confidence in the geological block model and to produce an updated MRE. This update to the MRE has been completed in conjunction with other technical work contributing to an updated feasibility study. This MRE required a reinterpretation and an updated geological model in order to represent the geological and mineralogical domains that have been defined by the most recent drilling campaign undertaken by the Company during 2022 and 2023.

The geological model includes mineralisation domains that are represented by the higher grade greisens "external", as well as a broader zone of lithium mineralisation contained within a mineralised albite lithium mica granite and "internal" higher grade greisens. The higher-grade external greisens are narrow in places but can reach up to 40 metres in true thickness, they outcrop above the mineralised zone of granite and internal greisens, with a typical separation but variable distance of approximately 10 metres. The broader mineralised zone has an average true thickness of approximately 80 metres and contains lenses of greisen that locally exhibit higher grades of lithium mineralisation.

Both the mineralisation zone and the greisens mirror the strike and dip of the host rock intrusion- the albite granite, as is typical of many greisen related roof zone deposits. Lithium mineralisation within all geological domains is hosted exclusively by polylithionite micas, or better known as "zinnwaldite" type micas. Lithium has been estimated using ordinary kriging methods and density using simple kriging methods.

Estimation has honoured the hard boundaries of the external greisens, internal greisens and mineralised granite domains, as well as using a dynamic anisotropic search method to honour the varying dip and dip directions of all estimation domains. This updated MRE differs from the previous MRE, completed in 2018, by incorporating the broader mineralised zone. The incorporation of the mineralised zone has allowed for a higher production rate and a reduction in unit processing costs.

Reasonable Prospects for Eventual Economic Extraction: NI 43-101 defines a mineral resource as that portion of the mineral inventory that has reasonable prospects for economic extraction ("RPEEE").  CIM Best Practice Guidelines for estimating mineral resources require the factors significant to project economics be current, reasonably developed and based on generally accepted industry practice and experience. In establishing the cut-off grade, it must realistically reflect the location, deposit scale, continuity, assumed mining method, metallurgical processes, costs and reasonable long-term metal prices appropriate for the deposit. Key assumptions have been provided to Snowden Optiro by Zinnwald Lithium for this MRE; these have been adjusted in accordance with the Company's understanding of costs associated with a higher production rate expected when mining a greater volume of material at a lower grade.  This includes metallurgical recoveries and mineral processing costs based on the results of ongoing metallurgical testwork.

The grade-tonnage curve inFigure 1.5demonstrate the robustness of the estimation to changes in cut-off grade around the 1,100 ppm Li grade. The 2024 MRE shows a 445 % increase in tonnage in the Measured and Indicated category over the 2018 MRE. This is predominantly due to the incorporation of the broad mineralised zone, as well as the significant increase in drilling meters (27,000m) and sampling intervals contributed by the 2022-2023 campaign.

A slight drop in the Measured category is in part due to the incorporation of internal greisens within the mineralised zone, and a more appropriate classification of higher confidence parts of the resource, taking into account, drillhole spacing, geological model confidence, mineralogical & metallurgical confidence and estimation quality. Snowden Optiro has recommended to Zinnwald Lithium that further metallurgical testing of the mineralisation zone be undertaken in order to convert parts of the mineralised zone currently defined as Indicated.