Round 13 Geophysics and Drilling Collaboration Program Final Report Greenfields diamond drilling Lake Mackay Project EL 30733 and EL 30740

Abstract

IGO Limited received co-funding support for diamond drilling in the southwestern Aileron Province as part of Round 13 of the Northern Territory Government's Geophysics and Drilling Collaborations (GDC) Program. The co-funded program involved the drilling of two diamond drill holes, one on EL 30733 and one on EL 30740. The drilling was completed between the 11th and 24th April 2021. Since 2014, IGO have successfully discovered several base and precious metal prospects in the southwestern Aileron Province. These include the Bumblebee and Grapple polymetallic prospects in 2015 and 2016, and the Grimlock nickel-cobalt, Phreaker polymetallic and Arcee gold prospects in 2019, and the Swoop nickel-cobalt and Goldbug gold prospects in 2020. These prospects were detected using combinations of airborne and follow-up ground electromagnetic surveys, and BLEG soil sampling. These mineralisation styles were unknown in the area before IGO began exploration. The co-funded drilling tested two electromagnetic conductors at depth, interpreted to be similar to those associated with polymetallic sulfide mineralisation elsewhere on IGO's Lake Mackay project. The two targets were originally identified from a regional airborne electromagnetic survey co-funded by the GDC Program in 2018. These anomalies were refined into viable drill targets, using additional data collected from follow-up ground electromagnetic surveys, soil sampling, and field mapping. The purpose of the drilling was to test for further mineralised sulfide bodies in a remote and underexplored greenfields area. No mineralisation had previously been reported in tenements EL 30733 and EL 30740. Drill hole 21LMDD001 at the Brawn prospect, intercepted sporadic intervals of low-grade sulfide mineralisation between approximately 380 to 435 m. The best interval intercepted 0.8 m at 2.1% Zn, 0.5% Cu, 0.1% Pb, 5.7 g/t Ag and 0.13 g/t Au from 405 m depth. The mineralisation is interpreted not to have significant tonnage to be considered economic. Drill hole 21LMDD002 contained several intervals of laminated and stringer pyrrhotite and pyrite between 298 and 346 m depth. No economic enrichments in base or precious metals were identified from assay results. Downhole EM surveys confirmed that the targeted MLEM plates were intersected during the diamond drilling and that no further drilling is required in the two drill target areas. Both targets are considered fully tested. The preliminary drill results have provided new metallogenic and geological information about the Aileron Province.