An originally large licence area centred approximately 70 km south-east of Tarcoola, which lies on the north-western margin of the Gawler Ranges and includes the north-western part of Lake Everard, is being explored for possible buried gold deposits that may have formed in Archaean and Proterozoic basement rocks. During the first licence year, the only work performed was a consultant's geophysical data interpretation of newly available airborne magnetic survey results produced by the SA Government's 1993 - flown SA Exploration Initiative Area A3 coverage. Eight magnetic anomalies were identified that Helix Resources thought could have potential for gold. The most important anomaly was believed to represent a possible greenstone belt associated with a major north-south aligned shear zone. Five others were thought to reflect more magnetic phases of the Hiltaba Suite granite, another might be an Olympic Dam type breccia pipe, and the last lay within a small linear structure located adjacent to the lake. During licence Year 2, on a licence area now reduced in size by 30%, a field programme of regional reconnaissance soil calcrete geochemical sampling was conducted across most of the licence except for within the Yellabinna Regional Reserve and on Lake Everard (part of the Lake Gairdner National Park). A total of 1100 samples were collected at 1 km intervals along traverses made down interdunal corridors spaced ~1 km apart, with the sampling interval closed down to 500 m above the Yarlbrinda Shear Zone (YSZ). Laboratory assaying of the +4 mm soil particle size fraction showed that the background value for gold is between 1 and 2 ppb Au, while low order anomalies have >7 ppb and high order anomalies >10 ppb. Five anomalies of the former type, and 10 of the latter, were recognised, and later in 1996, all except one were confirmed by infill sampling done at 200 m x 500 m precision. Most are associated with the YSZ, particularly its western margin. The largest two anomalies, together covering 25 square km, would lie over the YSZ were it rotated to the north-west. The other anomalies have much smaller footprints. The major anomaly pair, now called the Tunkillia prospect, is bounded by a 10 ppb Au contour and has a peak value of 230 ppb. It was concluded by Helix that calcrete sampling is an effective regional gold exploration tool for use in places where quality calcrete exists in the soil profile. However, it was shown that in places closer to the lake on EL 2028 the sand dunes tend to be younger, and have not developed the same strength calcrete horizons. When such thin calcrete is sampled it yields poor and unreliable/inconsistent results. In August 1996, a fixed wing airborne detailed magnetic/radiometric survey was acquired by Helix over the YSZ portion of EL 2028. 5752 flight line km were flown along ENE-WSW orientated lines 100 m apart, using a 50 m mean terrain clearance. The survey data highlighted the linear anomaly near Lake Everard as being significantly magnetic and worthy of drilling for possible kimberlitic diamonds. From late June until early November 1996, the licensee undertook exploratory RAB drilling on its gold prospects. 306 vertical holes were drilled initially at the Tunkillia prospect, spaced at 50 m intervals along seven traverses running at right angles to the interpreted YSZ trend, aiming to penetrate into and sample fresh bedrock beneath a ~50 m thick sand and laterite regolith profile. Four other high order gold-in-calcrete anomalies, and one magnetic anomaly, were drilled by 96 more holes spaced at 100 m intervals along fewer traverses. 4-metre composited drill cuttings from these holes were laboratory assayed down the entire length of hole. The strongest gold mineralisation was encountered at Tunkillia, defining six main anomalous zones. Follow-up stepout drilling of a further 96 holes was later conducted, along drill traverses running 100 m on either side of these zones, which demonstrated at least partial extension of the mineralisation in either or both YSZ axial directions. Two zones designated as Area 191 and Area 223 yielded the best results, of 4 m @ 4.29 g/t Au and 4 m @ 1.62 g/t Au respectively. The granite basement was found to be variably altered, either with haematite veining and brecciation or with sericite-chlorite alteration accompanied by mylonitic deformation features. More than 150 holes contain anomalous >0.1 ppm Au supergene gold within the weathered basement at redox boundaries. Clearly a large hydrothermal alteration system has been active along parts of the YSZ. Away from Tunkillia, RAB drilling done at the other gold-in-calcrete anomalies returned a best intercept of 4 m @ 180 ppb Au from anomaly LE-5 situated in the centre of the licence near the flexure point of the YSZ. Similar but weaker elevated gold was revealed at each of the other four anomalies, including the LEM-1 magnetic anomaly. During licence Year 3, activity consisted mostly of appraisal drilling at the Tunkillia gold occurrence, with only minor reconnaissance drilling done elsewhere. An ultra-detailed fixed wing airborne magnetic survey was acquired over Tunkillia, and trial ground gravity profiles totalling 62.5 line km were read there and across the YSZ to the south. Many drillhole cuttings and core samples were examined petrographically. A geological and structural interpretation of the whole licence area was commissioned from consultants Geointerp, based on the Helix airborne survey data and the earlier SAEI survey data. A total of 1817 vertical RAB holes for 103,853 m, 305 angled RC holes for 53,407.5 m, plus 13 diamond drilled holes for 1934.6 m of coring (either as discrete holes or as RC tails) were put in at Tunkillia, and essentially confirmed the generally low order bedrock gold anomalism dispersed there within sericite-altered granite, apart from in Area 223 where more consistent high grade mineralisation occur over a 600 m strike length in quartz-sulphide veins. During the RAB drilling, the bedrock's zone of weathering stratigraphy was logged according to a formal set of regolith unit codes. The YSZ - Tunkillia prospect ultra detailed magnetic survey totalling 4880 line km took place in April 1997 along ESE-WNW flight lines 25 m apart, using a 20 m mean terrain clearance. The survey results accurately delineated the two demagnetised zones, western and eastern (WDZ and EDZ), that mark the margins of the YSZ. These were interpreted to be due to alteration caused by fluids that have flowed through the shear zone. Later drilling was designed to test both demagnetised zones over their entire lengths at traverse spacings of 500 m or less, and hole separations of 50 m. Within the EDZ, RC drilling at Area 191 disclosed significant copper content (e.g. 8 m @ 0.1% Cu in hole LRC202) besides limited nearby high grade gold intercepts such as 7 m @ 5.3 g/t Au, and 13 m @ 1.97 g/t Au. Within the WDZ, the Area 223 gold occurrence was partly outlined, but other anomalies detected in RAB drilling await deeper RC drilling in order to properly explain the magnitude of the observed surface gold-in-calcrete anomaly. The mineralisation seen to date in drill cores from Area 223 appeared to be closely allied to veining with galena and pyrite varying in thickness from 20 cm down to <1 cm, and minor copper and zinc sulphides. The gold occurs as very fine grains within all of these sulphides, but metallurgical testing showed that only a small part of it is refractory, since effective recovery of the remainder was fast using a cyanide leach after a nominal standard grind. During licence Year 4, the following work was done by new joint venture partner Acacia Resources, who had begun operating the EL 2028 exploration programme: - 161 vertical RAB holes for 8925 m, which were drilled mostly peripheral to the main Tunkillia calcrete anomaly, encountered minimal gold; - Pontifex and Associates provided petrological descriptions of RAB drill cuttings and diamond tail core samples collected from both the Southern Dilational Zone and Area 223; - following the trial gravity profile surveyed in 1997, a more comprehensive 70 square km, grid-based 100 m x 200 m station spacing ground gravity survey of 2478 readings was acquired over the main Tunkillia area, and tied into the Australian Fundamental Gravity network. Hugh Rutter, of Flagstaff Geo-Consultants, then interpreted the resulting data and generated a number of prospective targets; - a comprehensive data review was undertaken of the drilling completed to date, with the focus on the 1 km strike length of Area 223. From this work a conceptual model for the structural controls and genesis of the gold mineralisation was developed from studies of eight diamond drill cores performed by consultant Bill Laing in concert with geologists from Acacia Resources. This model inferred that shallow to moderately plunging shoots containing high-grade vein style mineralisation had developed during low strain shear movement on the WDZ, synchronous with gold emplacement within the broader low-grade envelope; - RC appraisal drilling at Area 223, sited along the western margin of the Tunkillia prospect, targeted inferred plunging shoots of higher-grade gold mineralisation. A total of 16 holes for 2916 m were drilled. Results of this drilling did not significantly upgrade the potential for economic mineralisation, so work became focussed on defining the grade at depth for the rest of the Tunkillia anomaly; - the joint venture partners agreed to contribute to Gary Ferris’ University of Tasmania (CODES) MSc research and thesis on “Structural Interpretation and Geochemistry of Hiltaba Suite Granite within the Yarlbrinda Shear Zone, Western Gawler Craton, South Australia”. This work involved radiometric dating of the gold mineralisation encountered in drilling at Tunkillia; - additional surface soil geochemical sampling was undertaken around known calcrete-poor parts of the Tunkillia prospect, using the new alternative sample medium of pedogenic carbonate in an approach that arose from an improved understanding of the regolith. Some low order gold anomalism was detected around three outlying calcrete anomalies in the west and south-west, while some higher order gold anomalies were identified at Tomahawk and Area 191, both within the EDZ, and to the north of Area 223 within the WDZ. Acacia Resources stated that the use of gravity as a targeting technique appeared to have its limitations because the sericite alteration it maps out is apparently multi-phase, and thus to some degree is both time-wise and spatially independent from the timing of the gold mineralising event. In saying that, the company thought still that the strongly sericite altered granitoid basement unit appeared to be the best host unit for mineralisation, and so is still an important component of the mineral system. Therefore it was hoped that with a better understanding of the structural regime and alteration patterns controlling the placement of the mineralisation so far discovered, such insight could be applied to the geophysical survey results obtained over the rest of the tenement to generate other gold targets. During licence Year 5, between February and April 1999, the main activity was an investigation of the Tomahawk gold-in-calcrete anomaly via RC drilling of 36 angled holes for 5264 m, plus RC drilling of 3 further appraisal holes at Area 191 for 444 m. Laboratory assaying of basement section drill cuttings samples yielded minor gold values associated with quartz plus minor galena in veins and with sericitic alteration in sheared granitoid rock. The best intercept was 3 m @ 5.79 g/t Au from 100 m hole depth in LRC326. The mineralisation encountered did not explain the extent and magnitude of the surface anomaly. Regional reconnaissance surface calcrete sampling performed in a formerly unaccessed western part of the licence area lying within the Yellabinna Regional Reserve (140 samples) returned only weak gold and copper anomalism. A DEF had previously been submitted by Acacia Resources to PIRSA and DEHAA for both EL 2028 and EL 2181 Lake Everard West, approval of which allowed this work to be done under tight environmental protection conditions. 4WD quad bikes were used to traverse the reserve with minimal ingress impact. For making a trial of the utility of performing new geochemical sampling of just sand and surface crust regolith media, 80 soil samples were collected from sand dunes at Boggy Crossing where there is little or no pedogenic carbonate development. It was concluded that the technique would be ineffective for detecting gold and base metal pathfinders in such places. By the end of this reporting year, AngloGold had concluded that for gaining further success in gold exploration in the region a more conceptual model of the YSZ setting was required for generating targets, and the practice of taking an empirical approach to testing surface gold anomalies should cease. An application was made to PIRSA for renewal of licence tenure for a second 5-year term.