32 Impact Minerals Ltd Annual Report 2022 ABOUT THE MINERAL RESOURCE ESTIMATE AT SILICA HILL The mineralisation at Silica Hill lies between 60 m and 200 m north east of the Commonwealth deposit. It comprises a stockwork of veins and disseminations of gold, silver, zinc, lead and copper minerals typical of certain epithermal styles of mineralisation. Visible silver minerals such as proustite and pyrargyrite are common. The mineralisation is hosted by a large flow banded rhyolite flow or sill with large phenocrysts of quartz and feldspar throughout the unit. Within the rhyolite is a second porphyry unit of a different composition that separates the two main zones of mineralisation. The Silica Hill Resource strike length is 500 metres and it is open along trend in particular to the south. The mineralisation has been defined to a maximum depth of 290 metres and is still open. The Mineral resource comprises two limbs, one being south-south west dipping lode (South Lode) that truncates a north- northeast steeply dipping lode (North Lode). These Mineral Resources have a total strike length of 240 metres and extend vertically to about 190 metres below surface for the North Lode and to 290 metres below surface for the South Lode. The horizontal width is variable ranging from 4 metres to 40 metres and averaging 20 metres where the two limbs are separate and 75 metres wide where the two limbs join. Thirty four drill holes, 10 RC and 24 diamond, have been completed at Silica Hill, all drilled by Impact. Of these holes, 32 were used in the estimation to define a wireframe model. Quality control measures employed during drill programmes by Impact included the use of certified standards (1% of total sample population), field duplicates (2% of total sample population) and blanks (2% of total sample population). Analysis of the standards and blanks showed acceptable to good levels of accuracy in the assaying and little contamination. The duplicate samples matched the originals with a high degree of precision. The drill hole database was reviewed and validated. Three-dimensional solid wireframes were constructed from sectional interpretations of the mineralisation using a nominal 15 g/t silver cut-off grade. Drill hole intercepts were composited downhole to 1 m lengths and gold and silver grade estimation was carried out using top-cut ordinary kriging with hard boundaries. The top cuts used were respectively 525 g/t silver and 4.8 g/t gold for the north lode and 350 g/t silver and 2.5 g/t gold for the south lode. Three search passes, with increasing search distances and decreasing minimum sample numbers, were employed to fully inform the model. For silver 15% of the blocks and for gold 6% of the blocks did not receive an estimate in the first three passes. These blocks were assigned the nearest estimated grade. The Mineral Resource estimate for Silica Hill has been reported above a 50 g/t silver cut-off grade. The Silica Hill Mineral Resource estimate has been classified as an Inferred Mineral Resource in accordance with the guidelines of the Australasian Code for the 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, grade continuity and limited QAQC. No Measured or Indicated Mineral Resources have been defined. Review of Operations continued
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