Stuart Metals took up EL 2099 covering ground in the Wirrappa - Lake Blyth - Bookaloo Siding area primarily to explore it for stratiform copper mineralisation of the various styles present in the Mount Gunson area. In addition, it was thought that the concealed Mesoproterozoic basement there has significant potential for holding analogues of the Olympic Dam style of mineralisation, and for vein gold occurrences similar to recent discoveries which had been made at Challenger and elsewhere on the Gawler Craton. Because the basement geology of the Stuart Shelf area is so poorly known, it was envisaged as quite possible that other, unanticipated styles of mineralisation may be present also. During the first licence year, in February-May 1995, by cooperating with MESA for contracting its work, the licensee self-funded and flew a part an airborne magnetic and radiometric survey there to extend the SA Government's recent SAEI-funded 400 m E-W line spacing, 80 m mean sensor height Block B17 regional airborne geophysical survey coverage, and then made a preliminary interpretation of the data. The TMI readings showed "deeper" and shallower responses intermingled, and a decision was made to conduct advanced data processing in order to separate the deeper and shallow signals and to transform them such that they most closely related to their geological "causes". The processes carried out are known as "depth slicing" and "reduction to the pole". The products of this processing included a set of maps emphasising the shallow (0 - 300 m) magnetic features, an "intermediate" depth map (600 - 1000 m), and a basement map highlighting magnetic sources at depths of 3 km or greater. During licence Year 2, Southern Geoscience Consultants (Perth) were commissioned to make a detailed interpretation of the airborne survey data. This interpretation also utilised open-file company and government regional gravity data. Modelling of depth to pre-Pandurra basement was attempted, but in the absence of any rock susceptibility information and only limited geological constraint from sparse drillholes, confidence in the depth interpretations was not high. Profiles chosen for modelling generally coincided with those used for gravity modelling. Interpreted depths to magnetic basement bodies range from 300 m - 500 m to >1 km, and the values obtained agreed broadly with depths indicated by sparse regional drilling. Sixteen targets were identified that represented a variety of structural and lithological settings which could host copper-cobalt or gold mineralisation. These were categorised into: • repetitions of the Cattlegrid and associated styles of stratabound base metal mineralisation near the edges of basement highs, e.g. T1 to T3 [note - identifier T4 was not assigned]; • possible alteration zones and/or local igneous intrusive or contact breccia bodies, particularly those that might be associated with Hiltaba Suite intrusions, e.g. T5 to T10; and • structurally-controlled gold targets, e.g. T11 to T17. As a way of developing a possible tool for detecting blind mineralisation under variable thicknesses of Adelaidean sedimentary cover, Stuart Metals in late 1996 to early 1997 undertook an orientation soil calcrete geochemical survey involving three short sampling traverses over known mineralisation at Windabout and at MG 14, and two additional traverses to test the extremes of the range of surficial regolith environments likely to be encountered in the Mount Gunson district. Only one of the latter lines, at Bookaloo, was on the subject EL 2099, but information for the entire survey is presented to maintain completeness of the survey results and data evaluation. For the detailed traverses over known mineralisation, sampling sites were spaced at 100 m intervals, increasing to 200 m towards the end of each line. The 'regional' orientation lines involved sampling at 800 m intervals. After receiving assay results indicating elevated gold values on part of the Bookaloo traverse, two other short lines were added to this prospect's coverage, spaced 400 m to the north and to the south of the original sampling line. Overall, 114 samples were collected and assayed. Following evaluation of the orientation survey results, which lacked any strong trace metal dispersive signals, it was nevertheless decided to continue with calcrete geochemical sampling on a regional basis, because of the stated importance of the technique in finding the Challenger gold deposit and other buried gold occurrences within the central and western Gawler Craton. A sampling grid was laid out to cover all three exploration licences in the project area. The grid of 52 separate lines was based on a 1600 m line spacing, with samples being collected at 800 m intervals. A duplicate sample for analytical control was collected at every twenty-fifth site (approximately). The orientation traverses made at Elizabeth Creek and Bookaloo were incorporated into the regional grid. Between May and August 1997, soil calcrete samples were collected from 2343 sites, including from 1155 sites on EL 2099 which covered ~89% of that licence area (some salt lake crusts were found to be too moist and fragile to allow safe access onto the lakes for sampling lakebed soils). During licence Year 3, the new regional calcrete sampling assay data were assessed, and places having coherent anomalism were followed up with infill calcrete sampling (1732 samples) done at 800 m x 400 m site spacing along existing traverses plus 39 additional traverses, over the period October 1997 to January 1998. These places included the Winniepinnie, Bookaloo, and Bookaloo East prospects on EL 2099. Because of the patchy presence of calcrete on these prospects, it was decided to also do detailed soil sampling there at 200 m x 200 m spacing, for laboratory analysis by partial leaching with dilute HCl: this work started in February 1998 and was completed by May, for a project-wide total of 3741 samples, including 1440 from EL 2099. Interpretation of the assay results defined several possible drill targets. Dr Angela Giblin of the CSIRO performed detailed water chemistry analyses for Stuart Petroleum of 7 groundwater samples collected from drillholes located on EL 2099, using the specialist techniques she has developed. Data from these samples were added to a regional database for the Mount Gunson Project area, which now includes information about 66 groundwater samples. At the sample spacing achieved to date, regolith hydrogeochemistry must be regarded as merely forming an adjunct to the other mineral exploration techniques being used, rather than as a direct targeting tool in itself. Whilst appreciating that proper interpretation of hydrogeochemical data requires a detailed multivariate and solution-chemistry approach, plotting of the raw data did show a number of interesting features, i.e. elevated values for Pb, Zn and Co were detected in groundwater samples taken from drillholes which have intersected the Tapley Hill Formation at the Winniepinnie prospect, and this evidence supports the anomalous calcrete and soil geochemistry found there. Near the end of the reporting year, in July 1998, preparations were begun for carrying out an initial exploratory drilling programme on EL 2099. Partly this involved the conduct of two ground geophysical surveys, an EM survey at Winniepinnie and a small gravity survey at Bookaloo East. Work area aboriginal heritage protection clearance surveys were also performed for the proposed drill sites at this time, through inspection visits accompanied by representatives of the local Native Title claimant groups. At the star of licence Year 4, a set of moving 100 m x 100 m loop TEM survey readings were acquired across the 2 km x 1.5 km extent Pb-Zn-Co-Ag soil geochemical anomaly at the Winniepinnie prospect, which defined a conductive zone in the north-west corner of the prospect showing highs that might represent a thickening of the Tapley Hill Formation shale, or in one case possibly a local sulphide body. Two drill sites were picked to test them. During August 1998, 11 vertical RC holes for 386 m were completed at the Winniepinnie Dam prospect: 9 holes along two north-south traverses to test the polymetallic soil geochemical anomaly, plus another 2 holes to test TEM anomalies. All of the holes encountered the target Tapley Hill Formation at shallow depths beneath residual and transported cover, and were terminated within the underlying Pandurra Formation. Drillholes MGC 14 and MGC 15 at the southern end of Traverse 2 intersected black clay (weathered THF) containing percent levels of Pb and Zn, and visual logging of the deepest hole (MGC 16) identified fine grains of galena, but the maximum lead assay value returned from this hole was just 1800 ppm Pb. The main conclusion drawn from the drilling results was that the geochemical anomaly was reflecting directly sub-cropping Tapley Hill Formation. Since the stratabound mineral system model requires the complete host THF section to be covered by a suitable caprock, it was evident that further interpretation of the stratigraphic setting was needed in order to generate higher order targets in areas where the ideal reducing mineralising environment had been preserved. It was concluded that the main nearby area of prospectivity would lie under Whyalla Sandstone cover to the west of the Winniepinnie prospect, on EL 2567 Bowen Hill. A partial relinquishment of the whole of the north-western, Wirrapa sub-block of the licence was made in August 1999. During licence Year 5, no field work was done. Activities undertaken by licensee Stuart Petroleum NL / Gunson Resources Limited comprised: • ongoing interpretation and assessment of exploration data, in conjunction with new geochemical and geophysical surveys completed on the adjoining tenement EL 2567 to the west; • review and ranking of geophysical targets on EL 2099 versus those located elsewhere in the Mount Gunson Project area; and • commencement of a lithostratigraphic study of the potential for stratiform Cu mineralisation. Preliminary talks with Billiton Australia about a possible joint venture were begun. An application was made to renew licence tenure over the entire remaining area for a second five-year term.