Round 5 Geophysics and Drilling Collaborations Report, Illogwa (IOCG) Project

Abstract

At Illogwa, the presence of styles of alteration, mineral assemblages, and structural settings are consistent with known shear-hosted IOCG deposits (e.g., Eloise, Queensland; Hilllside, South Australia) and was compelling evidence that the project area may contain its own IOCG system. However, owing to weathering, the field evidence was not conclusive of the existence of an IOCG system. As such, the exploration concept was a fairly simple one: that potential IOCG mineralisation is hosted in northerly-dipping structures with recognizable strike. These structures required drill-testing to establish that an IOCG system exists. Only after that could the proper process of exploring for any IOCG deposit begin. To establish the existence of an IOCG system, drill core containing unequivocal IOCG mineralisation must be obtained. To assist in defining drill targets, Mithril Resources carried out IP surveys at Austin and Powers and detected a number of anomalies. Anomalies at Austin were chosen for drill testing. One of the IP anomalies at Austin was located 200 m down dip of outcropping copper mineralisation. The IP anomalies could be due to sulfides or hematite. At Bigglesworth and Mini Me, the presence of primary sulfides (Mini Me) or relatively abundant malachite (Bigglesworth) in mapped mineralized veins presented suitable drill targets. The objective of the drill program was to demonstrate the existence of IOCG mineralisation. Each hole intersected alteration and brecciation indicative of an IOCG system:. hematite-, magnetite-, chlorite-, and carbonate-alteration and veinlets in host rocks of the Atneequa granite (Figure 8a) and the Albarta Metamorphics and epidote alteration in the latter. Trace to minor pyrite and chalcopyrite were found in all holes except APDD003, which intersected the least altered and brecciated part of the system. Importantly, chalcopyrite in intense hematite-silica-altered granite was intersected over 3 m in APDD002 (Figure 8b), conclusively establishing the existence of an IOCG system. Fluorite and carbonate veinlets were also intersected in this hole (Figure 8c). Assays for this interval returned grades up to 0.67% Cu. Gold is also present in the system, but in small amounts. Grab samples have returned up to 1.4 ppm Au from hematite-quartz vein float. The highest grade found in the drill core is 0.09 ppm Au from brecciated, hematite-altered granite in APDD001. The mapped veins at Austin were intersected at predicted depths, as was the IOCG mineralisation in APDD002. However, veins mapped at surface at Mini Me and Bigglesworth do not persist down dip and predicted intersections of these veins were not realized. The three holes at Austin, APDD001-003, were sited to test IP anomalies. The amount of hematite-magnetite drilled in APDD001 and APDD002, plus the chalcopyrite in APDD002, may be the cause of the anomalies, but this remains to be established. The anomaly drilled in APDD003, which only intersected unaltered and weakly altered granite, is unexplained. Subsequent to this drill program, Mithril conducted extensive IP surveys immediately west Austin and at Mini Me. The IP anomalies west of Austin are interpreted to be due to groundwater. The anomalies at Mini Me are interpreted to be due to mineralisation and are expected to be drilled in the first half of 2013. Field observations provide poor constraints on the age of the mineralisation. It is younger than its youngest host unit, the 1745 Ma Atneequa Suite and probably older than 850-800 Ma Heavitree Quartzite, as the latter does not appear to host the IOCG mineralisation or alteration. The age of the IOCG system will have to be determined by isotopic methods. At this stage, there are no plans to drill test gravity anomalies as modelling shows their sources may be several hundred metres deep. Any drilling of gravity targets will be during a later phase of exploration.