14 Impact Minerals Ltd Annual Report 2023 Review of Operations continued ABOUT THE MINERAL RESOURCE ESTIMATE AT LAKE HOPE The Lake Hope Project (exploration licence E63/2086) is hosted in the Lake Hope palaeo-valley system within the Yilgarn Craton of Western Australia. The area lies within flat terrain with broad watercourses and dry bed lakes. The landscape also comprises sand dunes up to ~10m height, but with low relief. Vegetation comprises eucalyptus marri scrub to 12m height, heath, and scrub, with significant gum trees around the eastern dune areas, typical for that part of Western Australia. The palaeo-valley lake system is developed primarily upon Archaean granitic basement, with minor amounts of metamorphosed greenstone or sedimentary rocks present in the region as inclusions within the granites. The lake system comprises of a coherent series of evaporite playas up to 10 kilometres across which are partly obscured by aeolian dune systems. The saline playas are sheets of evaporitic deposits composed of aluminous mud kaolin, silica, goethite, halite, gypsum and minor amounts of quartz, feldspar and clay detritus. The alumina mineralisation is essentially an evaporitic lake bed deposit. Dimensions for the two mineral zones are; West Lake : areal extent 1.6 km by 1.6 km with an average thickness from the sampling of 0.95 m, maximum depth is 1.6 m and a surface area of 1.33 Mm2; and, East Lake : areal extent 1.6 km by 0.6 km with an average thickness from the sampling of 0.98 m, maximum depth is 2.0 m and a surface area of 0.76 Mm2. The style of mineralisation and the orebody type indicates that there is a strong horizontal control to the alumina grade and geological continuity, i.e. the mineralisation is flat lying and is exposed at surface. A total of 251 holes have been completed for a total meterage of 264.91m. The drilling consisted of 174 auger holes (for 215.67m) and 77 push tube holes (for 49.24m). A further 47 holes have been assayed but were not included in the mineral resource estimate. A total of 251 and 212 composites, West Lake and East Lake respectively, of nominal 0.5 m length were used to estimate Al2O3 for the mineralised lake sediments. No top cuts were applied to the data due to an absence of extreme values and low coefficients of variation for the modelled element. Auger sample quality is considered good to excellent based on moisture content, whilst the push tube sample quality is considered excellent. All holes were logged visually on 5-10 cm increments for colour, mineralogy, grain size, moisture and stiffness. No downhole surveys were taken as the holes are very short, <2 m, and are vertical. Limited QAQC data has been collected by IPT with results reported as being inconclusive due to insufficient data. The limited data is reported to include nine standards and 15 field duplicate samples. Laboratory performance for standards was acceptable for most major elements, with Loss On Ignition and silica exceeding the published values slightly. Duplicates showed acceptable deviance for 13 of the 15 duplicates (+/- 10%). The drillhole database was reviewed and validated by Impact’s independent database manager prior to provision to HS&C Mineral Consultants for an independent JORC 2012 Mineral Resource Estimation. Interpretation of the drillhole database resulted in the generation of 3D mineral constraining solids on 50 m spaced N-S sections for both lakes. The style of mineralisation and the orebody type indicates that there is a strong horizontal control to the alunite grade and geological continuity, i.e. the mineralisation is flat lying and is exposed at surface. A single mineral zone was defined for each the two deposits using a nominal basal Al2O3 cut-off grade of 20% and the geological logging of aluminous clays (providing the requisite geological control) in conjunction with SiO2, K2O, Fe2O3 and SO3 assay grades plus geological sense e.g. tapering of the mineral zone at the lake margins. A 2D digital plan outline of the two deposits was taken from IPT’s geological mapping (based on an air photograph interpretation) and used to limit the boundary of the mineralisation. Where the base of mineralisation was not necessarily intersected by the drilling, the interpreted basal surface for the mineralisation was extrapolated from nearby drillholes which had reached the base, usually in slightly granitic clay sediment. The top of mineralisation was aligned with the sectional topographic trace from the gridded Lidar data. The Lake Hope Resource has been classified as predominantly Indicated Categoery with approximately 11% Inferred Resources, and has been reported in accordance with the guidelines of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC Code 2012). Mineral Resources have been classified on the basis of confidence in geological and grade continuity, geological modelling confidence, and limited QAQC.
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