In 1993 the SA Government flew a regional aeromagnetic survey over the western Gawler Craton as part of the South Australian Exploration Initiative, which prompted North Ltd to change direction with its BARTON area exploration programme, to address the base and precious metals potential of the Precambrian basement underlying the Tertiary shoreline sediments of the Eucla Basin. To begin with, limited petrology was done on basement samples derived from North's previous mineral sands drilling, which showed that much of the basement has undergone upper amphibolite to granulite facies metamorphism, apart from minor lower grade, possibly regressive exceptions in shear zones. Ground magnetic traverses over prominent interpreted structural features were completed next, along with five traverses of follow-up aircore drilling (65 holes, total 2997 m) which demonstrated that the basement rocks causing a regional magnetic and gravity high which extends across EL 1597 consist of high grade meta-pelites, amphibolites and granitoid gneisses. None of these rocks were found to contain significant mineralisation, although anomalous copper was located in several holes, e.g. BAC43 intersected 468 ppm Cu from 12-26 m depth in a weathered, quartz-veined and quartzose amphibolite, and BAC60 intersected 300 ppm Cu at its deepest interval (63-66 m), in a foliated biotite and scapolite-bearing amphibolite. At this stage in the work, because North felt that the obviously complex basement geology was still insufficiently known to formulate effective exploration models for the area (including a lack of knowledge of the geochronology of the cored metasediments and igneous intrusive rocks), it decided to farm out the licences to another joint venture partner. Inco Ltd of Canada came in as operator for the period May-December 1995 to explore for nickel; however, because of other priorities which arose, that company undertook no field work in its time of tenure. After North resumed the operatorship in December 1995, it analysed for this element also as part of its regional gold-in-calcrete program: the highest nickel assay values (up to 40 ppm Ni against a background of 3-6 ppm) occurred on the Lake Tallacootra traverse, although some scavenging of nickel by manganese was evident from the results. In the earlier aircore drilling of this traverse, anomalous nickel (to 310 ppm Ni with 1540 ppm Mn) had been recorded in hole BAC8 from weathered schist. Following the calcrete-based discovery of the Campfire Bore and Golf Bore gold prospects in the basement to the Mulgathing region by the Resolute Resources-Dominion Mining joint venture, North undertook an orientation survey of pedogenic carbonates in its BARTON project tenements, looking for similarly indicative gold traces. The results were disappointing and inconclusive: a maximum of only 3 ppb Au was obtained from 71 calcrete samples obtained by hand-held power auger at 1-2 km spacings along a transect across ELs 1865 and 2044, west of the Ooldea dunefield; the regional background is clearly 1 ppb Au or less. From the earlier aircore drilling work, only hole BAC61 had intersected anomalous gold (32 ppb Au) in the 39-45 m depth interval, but no calcrete development was present in the drillhole; only minor calcareous sand was found down to 2 m in the vicinity, but none of this material was gold-bearing. On the other hand, the maximum aircored gold-in-calcrete (5 ppb Au) was from a hole which intersected only 2 ppb Au in basement. Local cover thicknesses ranging from 6 to 93 m, complications from the presence of interbedded Nullarbor Limestone and silcrete and ferricrete hardbars, and potential long-term leaching of the originally exposed calcrete by rainwater were all seen by North as complicating factors to its applying the method confidently on the BARTON licences.