Impact Minerals Limited Annual Report 2021

BROKEN HILL PROJECT Impact Minerals Ltd Annual Report 2021 8 The success of the drill programme was driven by the discovery by Impact of a geochemical ratio that can be measured with a hand held XRF instrument at the drill site that shows a relationship to the grade of palladium+platinum+gold as determined by laboratory assays. 1.1 About Impact’s Ratio for PGM Exploration In the normal course of exploration there is a significant time lag between drilling for PGM mineralisation and receipt of assays. This is because PGM minerals are mostly not visible to the naked eye, do not occur in association with visible sulphide minerals and can not be read directly with hand held instruments because of the high detection limits for precious metals. Accordingly there is usually a significant time lag between drilling, receipt of assays and follow up drilling. The ratio allows the drill rig to track mineralisation in real time during the programme. This is possibly a first in PGM exploration globally and is a major advantage for Impact as it moves forward with follow up drill programmes that are clearly required at Broken Hill. Figure 1.1 shows a graph of the relationship between Impact’s geochemical ratio and grades of platinum+palladium+gold (3PGM) as determined by laboratory assay for all available data at the Platinum Springs prospect (ASX Release 6 th October 2020). The positive log linear relationship between the ratio and 3PGM grade is self-evident in the figure. It suggests that anomalous grades of more than 100 ppb 3PGM are generally associated with ratios greater than 2 to about 5 and that ratios greater than 20 are likely to have 3PGM grades greater than about 1.0 g/t. Figure 1.1. Graph of platinum+palladium+gold (3PGM) in parts per billion (1,000 ppb = 1 g/t: y axis) against Impact’s proprietary ratio (x axis). Note key thresholds at a ratio of between 2 and 5 and also in particular of more than 20 that mark increases in grade of the 3PGM. Note also that there are some exceptions to the rules.