お知らせ • Feb 06
Andrada Mining Limited Announces an Updated Mineral Resource Estimate for the V1v2 Pegmatite At the Uis Tin Mine
Andrada Mining Limited announced an updated Mineral Resource Estimate ("MRE") for the V1V2 pegmatite at the Uis tin mine. This is an update on the MRE announced on 6 February 2023, and incorporates analytical results from the final 16 drill holes of the 2022 drilling programme, as well as a volume depletion surface as at 30 August 2024. results Overview: The MRE has been informed by 145 historical ISCOR drillholes comprising eight (8) Diamond Drillholes ("DD") and one hundred and thirty-seven (137) Reverse Circulation ("RC") drillholes, together with seventy-seven (77) validation drill holes, comprising forty-eight (48) DD and twenty-nine (29) RC drillholes drilled by Andrada between 2018 and 2023. The Andrada drillholes were completed on a nominal grid spacing of 60m by 60m, with wider spacing of up to 80m by 200m for the deeper portions. Most holes were drilled at a vertical orientation, but selected shallower holes were inclined at angles up to -70° southeast, to obtain intersections more perpendicular to the dipping pegmatite. The 2023 MRE update was determined from geological information of all holes above, except for 16 holes (V1V2034, 35,37, 38, 40, 43, 44, 48, 50, 51, 52, 53, 54, 58, 63 and 80) whose data were not available at the date of publication. The current MRE update includes analytical data from the final 16 drillholes obtained subsequent to the previously published MREs. The updated V1V2 MRE is reported in accordance with the JORC Code (2012) and identifies 77.51 Mt of mineralised pegmatite with an average grade of 0.79 % Li2O, 0.15 % Sn and 82 ppm Ta. This MRE includes 27.33 mt at an average grade of 0.82 % Li2O, 0.15 % Sn and 90 ppm Ta for the near surface Measured category, 17.50 mt at an average grade of 0.79 % Li2O, 0.15 % Sn and 86 ppm Ta for the Indicated category, and 32.68 mt with an average grade of 0.76 % Li2O, 0.16 % Sn and 73 ppm Ta for the Inferred category. The contained lithium is also stated in terms of Lithium Carbonate Equivalent, being the metal converted to lithium carbonate by a factor of 5.323. The MRE is reported within a conceptual pit shell to demonstrate reasonable prospects for eventual economic extraction("RPEEE") and incorporates the sale of petalite and cassiterite. Rubidium (Rb - in mica), tantalite and niobium associated with Ta in the columbite group minerals (CGM)) concentrations and tonnages were also estimated but have not been included in the RPEEE considerations. An attributed-basis tabulation of resources, as presented in previous estimates, is no longer applicable because the V1V2 pegmatite is within the Uis mining license (ML 134) now wholly owned by Andrada Mining and its subsidiaries (see announcement dated 27 June 2024). Geology and geological interpretation: The V1V2 deposit is hosted within rocks formed during the Damara Orogen, a typical Pan-African orogenic belt, which formed between 750 Ma and 440 Ma during the assembly of Gondwana. The orogenesis resulted in the production of voluminous quantities of granitic magma during the syntectonic phases of collision. This was followed by a pegmatitic phase of magmatism in the post-tectonic environment, populating the Damara Orogen with numerous pegmatitic intrusions. The V1V2 pegmatite has a sigmoidal shape in plan and is hosted in biotite schists and a distinctive cordierite (with biotite and quartz replacement of cordierite)-bearing knotted schist (the so-called "knottenschiefer"). The pegmatite strikes to the northeast and dips to the northwest at angles of between 30° and 50°. The tin and lithium mineralisation is primarily magmatic with some tin mineralisation associated with a late-stage mica-rich greisen phase. The primary lithium mineral identified within the pegmatite is petalite. Modelling and estimation: An in-situ Mineral Resource Estimate (MRE) was undertaken for the pegmatite bodies. Mineralisation wireframes were guided entirely by geology and resulted in the generation of three-dimensional (3D) geological models of the V1 and V2 pegmatites that merge at depth to form the V1V2 pegmatite body. The pegmatite wireframes were also used to define the mineralisation envelopes. Internal waste was represented by the xenolith wireframes. The August 2024 monthly photogrammetric survey at Uis was used to generate a high-resolution topographic surface that was subsequently used to constrain the resource. A block model, constrained by the interpreted mineralised envelopes and topographic surfaces, was constructed. A parent cell size of 20 m(E) x 20 m(N) x 10 m(RL) was adopted with standard sub-celling to 2 m(E) x 2 m(N) x 1 m(RL) to maintain the resolution of the mineralised lenses. The samples were composited to 2m lengths. A small number of tin samples were considered grade outliers, and a top-cut of 1.0% for Sn applied to the dataset (only Sn grades were top-cut). These composites were the basis for the estimation of all Sn, Li, Nb, Rb and Ta grades into the block model using Ordinary Kriging (OK) interpolation, with the V1 and V2 pegmatites treated as separate domains. The block grades were validated both visually and statistically against composite grades. A mean dry bulk density value of 2.65 was assigned to all pegmatite material.
