In 2008, as part of work being performed for it to earn a 51% interest in the Mundi Mundi Plains joint venture exploration licences, Teck Cominco identified two geophysical targets within South Australia on Kalkaroo EL 3328 which it thought were worthy of drill testing; the Yarramba gravity anomaly, and the K16 near-coincident magnetic/gravity anomaly. The Yarramba prospect is a significant residual gravity anomaly, up to 5 mGal amplitude, sitting within the hinge of a broad antiformal fold feature called the Yarramba Antiform. The characteristics of the Yarramba gravity anomaly were considered to be favourable for finding MacArthur River style or Broken Hill type mineralisation. The K16 prospect lies in an area of highly magnetic horizons (the Polygonum trend) originating from iron rich, magnetite BIF horizons hosted within quartzites and quartz-albite sequences, deposited in an oxidizing environment. The sedimentary sequence is inferred to be deposited in a basinal sequence bounded by a series of normal faults running parallel to a regional horst structure. Through Hills' (2006) modelling, there is evidence for the current stratigraphic/structural architecture to have resulted from re-activated normal faults forming thrust-stacked magnetic units that appear to verge/buttress against a regional horst feature. The K16 prospect represents a discordant, NW-SE trending gravity high bounded by a 'tram track' fault pair, that also crosscuts the strike of the interpreted thrust duplex. It was thought by Teck that these tram track faults may have acted as controlling structures that could lead to a favourable setting for discovering IOCG mineralisation similar to that at the Ernest-Henry deposit. In consequence of developing these prospectivity models, an application was submitted to PIRSA for the grant of PACE Initiative Year 5 funding, and this was granted to the company on 11/9/2008. The planned drilling project (designated DPY5-21) involved completing a single vertical HQ/NQ diamond hole on each target, to a depth of ~400 m. During the period July-August 2008 Yarramba drillhole YM-01 was drilled to a depth of 417.6 m, and hole K16-01 was drilled to a depth of 372.7 m, for a total combined penetration of 790.3 m, including the rotary mud or RC drilling of suitable precollars which had 200 mm PVC casing cemented into place to protect aquifers within the sedimentary cover sequence. YM-01 encountered Palaeoproterozoic basement from 82.8 m depth to TD, which consists of Willyama Complex lower amphibolite facies metapelitic and psammopelitic units comprising shales grading up to phyllite and low grade metapelites. These rocks have minor sulphide mineralisation present throughout, which is principally contained within highly deformed and sheared quartz veins, and is commonly composed of pyrite with lesser chalcopyrite and very rare sphalerite. The absence of thick intervals of dense lithologies (that would contribute to a high amplitude gravity response) means that the targeted gravity anomaly has not been explained. K16-01 encountered Palaeoproterozoic magnetite-BIF quartzites of the Willyama Complex from a depth of 64.0 m to TD. In detail this basement consists of bedded quartzite, very fine-grained siltstone and magnetite BIF, chert and jasper. The lack of any drill core indications of broad, district to prospect - scale alteration and brecciation was regarded as discouraging. Teck subsequently conducted a brief review of the geochemical results from the two PACE drillholes. Although hole K16-01 did not intersect IOCG style brecciation or mineralisation, it was believed that evidence had been found (elevated base metal values associated with stratabound and possibly stratiform pyrite) which suggests the possibility of a Northern Australian sedex style mineralising system occurring nearby. It was also interpreted that hole YM-01 is likely to be distal to any such mineralisation. Despite this disappointment, Teck still considers the Yarramba anomaly setting to be permissible for forming MacArthur River style mineralisation, however, a better understanding of the basin architecture will be required to identify drill targets in closer proximity to intersections with major growth faults and transfer faults.