The Archaean Metabasic Diamond Drilling Project was undertaken by SADME Regional Geology Branch (part of the Geological Survey of South Australia) in two locations within the north-western Gawler Craton. Metasediments in this region include banded iron formation, quartz+-feldspar+-garnet+-cordierite gneiss, calcsilicate, carbonate and quartzite. These rocks are interlayered with or were intruded by basic and ultrabasic flows or sills prior to granulite facies (locally amphibolite facies) metamorphism during the Sleafordian Orogeny which occurred at 2640-2450 Ma. The metasediments and metabasic rocks were also intruded by late orogenic granites and tonalites at this time. The paragneisses, metabasics and late tectonic intrusives are all included within the Archaean Mulgathing Complex. Correlation with the Sleaford Complex in the southern Gawler Craton indicates that the age of sedimentation for the Mulgathing Complex is greater than 2640 Ma on a basement (estimated from Sm-Nd model ages) as old as 3000 Ma. Banded iron formation, quartz+feldspar gneiss and gneissic granite occur most frequently in outcrop, whereas basic and ultrabasic rocks (granodiorite, norite, pyroxenite, gabbro, peridotite, komatiite, bronzitite, lherzolite) are rarely exposed and are deeply weathered. Limited auger and percussion drilling has indicated anomalous nickel and chromium values in these shallow metabasic rocks. The subject project was specifically planned to obtain fresh samples of these basic and ultrabasic rocks and to give an understanding of their structural relationships with the host paragneisses. Petrology, whole rock and trace element geochemistry were planned to assess the exploration potential and probable tectonic setting for these very poorly known rocks. The final aim for the drilling project was to determine whether the basic and ultrabasic rocks of the Mulgathing Complex are similar lithologically to those of the Eastern Goldfields Province of Western Australia and, if so, to determine their potential for gold, nickel, platinum and chromium enrichments of the type which are associated with Archaean MgO-rich rocks in that province. At Kambalda, for instance, the extrusion age for nickel-bearing rocks is inferred to be 2692+-6 Ma, while the gold mineralisation at Kalgoorlie is slightly younger at 2675+-6 Ma.