In late 2008 PepinNini Minerals completed a stratigraphic drilling programme in the western Musgrave Province as an approved PACE Initiative Year 5 collaborative project with PIRSA. The programme was designed to investigate the Mount Caroline intrusive body of Proterozoic Giles Complex mafic/ultramafic rocks, as well as the surrounding older felsic basement rocks of the Birksgate Complex. Specific project aims were to provide sufficient drill core samples of these rocks to allow an improved understanding of their petrological, petrophysical and geochemical properties, whilst also assessing their prospectivity for hosting economic deposits of nickel-copper sulphides, in particular Voisey's Bay type massive Ni-Cu sulphides, plus likely associated non-ferrous base metals and platinum group precious metals. The PACE-subsidised drilling activities were conducted as part of a broader exploration drilling programme being undertaken by PepinNini Minerals within EL 4048 to investigate conductive zones identified by electromagnetic surveys and regional magnetic and gravity anomalies over interpreted mafic/ultramafic intrusive lithologies of the Giles Complex. All of this work has been undertaken with the approval of Anangu Pitjantjatjara Yankunytjatjara and Traditional Owners of the area. Project DPY5-18 consisted of six diamond drillholes having a total penetration of 2423.96 m. Four of the holes were drilled within the area of shallow sedimentary cover that is interpreted as being underlain by parts of the Mount Caroline intrusion, while the remaining two holes were drilled to investigate sites of low magnetic remanence that are associated either with this intrusion or the surrounding country rock. Drillholes that penetrated the Mount Caroline intrusion proper, or that only intersected minor parts of it, encountered gabbronorite, gabbro, troctolite and anorthositic gabbro of the Giles Complex, while the sections of holes drilled within the surrounding country rock encountered felsic and mafic gneisses of the Birksgate Complex and granite of the Pitjantjatjara Supergroup. Primary disseminated sulphides were encountered in all the drillholes which targeted the Giles Complex, being predominantly iron sulphides (pyrrhotite and pyrite) with trace amounts of Cu-Fe sulphide (chalcopyrite) and Fe-Ni sulphide (pentlandite). DD08CAR001 and DD08CAR004 contain the highest proportion of sulphides, although these mineral occurrences are not of economic significance. The continuity of sulphide mineralisation across the Mount Caroline intrusion between recorded drill intercepts has yet to be determined. The proven presence of primary sulphides within the Mount Caroline intrusion, in proportions ranging from trace amounts to 5-25%, indicates that the parent magma reached sulphur saturation, this being a major prerequisite for forming cumulate massive sulphide accumulations. Magnetite was encountered in all of the drillholes, and occurs most abundantly within megacrystic anorthositic gabbro of the Mount Caroline intrusion. DD08CAR002, which was drilled into a magnetic low anomaly interpreted to reflect an intrusive plug or feeder pipe, cored through rocks containing significant amounts of magnetite, which have magnetic susceptibilities in the order of 60,000-100,000 SI, thus highlighting the importance of an awareness of the presence of remanent magnetism when interpreting causes for low values in the magnetic data for this region. Petrographical interpretations suggest that the drilling done to date into the Mount Caroline intrusion has penetrated the middle or upper part of a layered mafic/ultramafic intrusion. Subsolidus modification of the primary igneous mineralogy suggests that emplacement of the igneous rock body occurred at mid-crustal depths. The rock geochemical data highlight the fact that dynamic magmatic processes were operating during the development of the Mount Caroline intrusion. It probably formed through successive magmatic pulses sourced from a parental melt that was being intermittently replenished and contaminated by the surrounding country rock.