The Harris Greenstone Domain bedrock drilling program - Phase 1, carried out during May to August 2001, has determined depths to basement, the basement lithology, and has outlined areas of anomalous gold, nickel and chromium geochemistry within greenstones of this still little explored and poorly defined domain. To date, 131 new PIRSA stratigraphic drillholes totalling 5903 m have been completed, comprising 4952 m of aircore open hole percussion drilling, and 951 m of diamond drilling. This drilling has increased the known strike extent of previously delineated, exposed komatiite - bearing sequences at Lake Harris, Hopeful Hill and Mullina Well. The meta-komatiite encountered is predominantly of low to mid - amphibolite facies metamorphic grade. U-Pb SHRIMP dating of zircons from an interbedded interval of rhyodacite gave an age of ~2510 Ma, which is interpreted as the host extrusive's age of crystallisation. These latter rocks are presumed to have been deposited contemporaneously with the komatiite flows. Given that the previously established metamorphic grade ranges up to granulite facies for the Christie and Kenella Gneiss units, it may be inferred that the observed differences in metamorphic grade reflect discrete, previously unrecognised yet major depositional episodes within the Archaean. Petrology has identified a few samples of volcanic rock of greenschist facies within the greenstone sequence. It is possible that they are of an age younger than the greenstones and older than the Gawler Range Volcanics, though the poor sample quality does little to firmly support this rather problematic conclusion. Drillholes put into the Lake Harris Komatiite have demonstrated excellent examples of these rocks' spinifex texture, adcumulate olivine and possible harrisitic texture, the first recorded in South Australia. At Mullina Well, diamond drilling along two sections across the komatiite has confirmed, on the eastern section, a sequence comparable to that encountered at Lake Harris, and on the western section, a sheared sequence of predominantly komatiitic pyroclastics with thin interbeds of komatiite flows and rare intervals of metasediments. Geological correlation between these two sections remains unresolved, but further investigations by age dating offer possible solutions.