Iron ore mineralisation similar to that mined in the Middleback Range has been investigated at the Hercules prospect, located 90 km west-northwest of Whyalla, where a large, high intensity aeromagnetic anomaly and associated 12 km long outcrop of banded iron formation (BIF) occur. During previous base metal exploration work done here, surface rock chip sampling by licensee Trafford Resources had returned up to 59.8% Fe from the southern end of the BIF outcrop. In view of the obvious large tonnage iron ore potential of the locality, and its evident geological and geophysical similarities to the nearby Middleback Range iron deposits, where over 200 Mt of direct shipping ore has been mined in the last century, an application for PACE Initiative Year 5 funding to assist with exploratory drilling at Hercules was submitted by joint venturer Ironclad Mining, which was soon approved. Subsequently, after the acquisition of additional 100 m flight line - spaced detailed aeromagnetic data over the magnetic anomaly, besides obtaining new gravity data at 250 m station spacing to refine drilling sites, a PACE-subsidised drilling programme of 64 grid-based reverse circulation percussion holes totalling 8925.5 m of penetration was completed during August 2008. As well, Ironclad Mining used part of the PACE subsidy to fund the directional drilling of a diamond fully cored hole to TD 281.1 m to collect bulk ore samples for undergoing preliminary metallurgical tests, and to allow a better understanding of the local stratigraphy. Three types of BIF - related iron ore mineralisation, namely, massive enriched hematite (high grade, direct shipping ore), lower grade magnetite BIF and lower grade hematite BIF (which both require beneficiation), were considered prospective targets. Ironclad Mining has either observed or interpreted the following features at the Hercules prospect and therefore, by analogy with known Middleback Range orebody settings, considers them key search parameters for finding economic iron mineralisation: - regional structuring, i.e. the principal Middleback Range iron deposits are controlled by major N-S orientated shears; - a stratabound setting within BIF rocks, specifically the Lower or Upper Middleback Jaspilite, where such occurrences have associated high intensity magnetic signatures; - synclinal settings appear to be favourable, again by analogy with the Middleback Range. Furthermore, the western limbs of synclines, and possibly a spatial association with mafic dykes, empirically seem to be important. The fold hinges are likely to contain larger orebodies because of thickening of prospective strata; - the presence of cross-cutting structures, in particular, NW-SE trending structures, appears to be important for localising high grade iron ore; - localisation of iron deposits on the ends of linear magnetic anomalies; - evidence of supergene enrichment of primary magnetite to hematite; - the nearby presence of Hiltaba Suite granite intrusions, as a possible source of iron-rich fluids. The PACE drilling programme results have confirmed the presence of magnetite-bearing BIF overlain by deeply weathered BIF and younger sediments, to depths of >80 m. The outcropping Lower Middleback Jaspilite BIF facies in the subsurface was largely found to be a banded silicate and oxide facies iron formation. The highest Fe and Mn grades are associated with goethite in this unit. The composition of the siliceous banding varies from 20-60% SiO2, and is antipathetically related to the Fe content. Silica-rich quartzite and chert bands are evident, but are not traceable at the current drill spacing.A carbonate facies BIF was first noted in the diamond hole 08HCDH001, and is characterised by thin ( 5% and Fe+Mn > 40%. Magnetite BIF - The primary mineralisation is typical magnetite - bearing BIF, grading around 25% Fe. There is a transition zone of less magnetic, weakly oxidised BIF at approximately 80-150 m vertical depth. The fresh magnetite BIF has an average magnetic susceptibility of around 175 x10-3 SI units as measured on a hand-held susceptibility meter. An initial JORC-compliant haematite-magnetite and goethite ore resource of 216 Mt has been defined at Hercules as of December 2008 (including the separately-drilled portion of the deposit which lies on Lincoln Minerals adjoining EL 3690 to the south).