In ongoing diamond exploration of the Flinders Diamonds Ltd (FDL) Springfield Project tenement group, the licensee undertook exploratory drilling for kimberlite in the Springfield and Boolcunda Basins, and at the former Eurelia prospect of Stockdale Exploration. Beginning in November 2002, 19 holes were completed on five targets, comprising 70 m RAB, 311.9 m rotary mud, 519.2 m aircore and 129.8 m of NQ core drilling. Of particular note, two holes (BLRD01 and BLAC02) were drilled to test the Global Kimberlite Emplacement Exploration Model target in the centre of the Boolcunda Basin. Hole location was based on an interpretation of FDL's previously acquired gravity and seismic data. Both holes failed to adequately test the target zone. BLRD01 was drilled to 484.9 m total depth, but due to its strong deviation from vertical was not successful in testing the target zone. A second aircored hole (BLAC02) was collared close to BLRD01. This hole was abandoned at 90 m depth, again due to deviation from vertical. Both holes appeared to climb against rotation along a preferred 305 degrees true direction. Although no evidence of a metamorphic fabric was recognised, the basal sequence of sandstone below ~403 m depth was interpreted as being probable Adelaidean, possibly Umberatana Group. Supporting evidence includes a slight shift to higher density below the interpreted unconformity, and the presence of oolitic units within the denser sandstones. A kaolinitic sandstone above the oolitic/sandstone sequence in BLRD01 was interpreted as being of probable Triassic age, based on the evidence of kaolin and disseminated siderite compared with a dolomite-sericite-chlorite assemblage seen in the Adelaidean units. The kaolinitic unit was correlated to a 48 m wide (~37 m true thickness) sandstone sequence intersected at the base of the Freeport hole DDH6 located ~ 470 m NW of BLRD01. However, the presence of an oolitic unit (albeit finer-grained than the BLRD01 oolite zones) located stratigraphically above the kaolinitic sandstone in DDH6 was problematic, but may represent a secondary reworking of underlying Adelaidean oolitic rocks. 53 drainage samples, collected as part of the ongoing regional geochemical search for kimberlite that started in 1998, found numerous chromite indicators in areas immediately east and south-east of the limits of the Springfield Basin. Excavation of 30 shallow pits and trenches commenced in three anomalous areas during October 2002 to test various topographic, magnetic and geochemical targets locally associated with the indicator mineral anomalies. Bedrock was exposed in all pits. No kimberlitic rocks were identified. During calender year 2003, exploration done by FDL included: - regolith mapping, geophysical (aeromagnetic and gravity) surveying and drilling at the Eurelia prospect (EL 3131); - deep drilling in the Springfield and Boolcunda Basins (EL 3003); - indicator mineral sampling and petrological examination of Boolcunda BLRD01 drill core; and - indicator mineral sampling, including regional drainage and follow up drainage and loam sampling, at Round Hill and Radford Creek (ELs 3003, 3132 and 2868). Kimberlitic dykes near Eurelia previously identified by Stockdale in the late 1970s and early 1980s are located in areas dominated by erosional regolith, where indicator minerals could be traced to source within current drainage features. However, FDL's aircore drilling of 5 holes in 2002 had tested the depth of cover (and for possible kimberlite targets) in areas of depositional regolith associated with low magnetic relief interpreted from Stockdale's 1979 aeromagnetic survey. No kimberlitic rocks were encountered, but an average 34.5 m depth of cover at three sites (EU1, EU2 and EU5) indicated that a strong chance exists for the masking of kimberlites at depth. A more detailed aeromagnetic survey was considered warranted. A low-level aeromagnetic-radiometric-digital elevation model survey was flown for FDL by UTS Geophysics during February 2003 (1919 line km along 100 m spaced north-south lines with ~40 m sensor height above ground level). 1:25,000 scale regolith mapping over the Eurelia kimberlite province, and within the same region covered by the above new aeromagnetic survey, was designed to identify areas of depositional regolith that have possibly prevented eroded detritus of kimberlite pipes (and dykes) from entering the current drainage lines. A central zone defined as deep depositional regolith was targeted for gravity surveying. A gravity survey comprising 1073 stations was completed for FDL by Haines Surveys in May 2003. Coverage comprised a 160 m x 160 m (offset) grid (816 stations) with selected infill to 80 m station spacing over four areas, and to variable 80 m and 40 m station intervals in the area east of the Stockdale K7 kimberlite blow. Infill areas were selected over gravity lows of at least 0.5 mGal. The gravity data was processed and reviewed by consultant geophysicist Chris Anderson, who noted that the K7 kimberlite, interpreted by Stockdale as a body with a footprint of about 15 m x 40 m, is not readily defined in the data at 40 m station infill around the site. This indicated that the current survey was unlikely to disclose any small kimberlite bodies. Selected gravity lows and a number of other features were identified as possible kimberlite targets warranting drill testing. Aircore drilling through deep cover at Eurelia was carried out during November 2003 (39 holes totalling 1431 m). The holes were drilled to test residual gravity lows, gravity lows associated with structure and as a general test of cover depth through the zone of depositional regolith. Most holes reached interpreted Proterozoic (Adelaidean) basement. Basement units were interpreted as Neoproterozoic Burra Group and River Wakefield Group metasediments, comprising mainly siltstone and dolomitic units. No kimberlitic rocks were identified. Re-drilling of targets beneath the centres of the Springfield and Boolcunda Basins during 2003 was successful, after a diamond drilling rig with heavy brass stabiliser rods was employed to minimise any hole deviation from vertical. Unfortunately, no kimberlite or indications of proximal kimberlite rock were identified. Hole BL3 in the Boolcunda Basin was completed at 500 m depth on 11/11/2003. Adelaidean basement was reached at approximately 454 m depth. There is evidence of a karst-type surface at the interpreted unconformity, similar to a surface identified in hole BLRD01. Hole SpB12 in the centre of the Springfield Basin was completed at maximum depth of 544.3 m on 9/12/2003. It intersected a thick sequence of sandstones, carbonaceous units (including coal) and conglomerate lithologies interpreted as Triassic sediments. Proterozoic metasiltstone basement, interpreted as Tapley Hill Formation, was encountered at 494.3 m depth. No kimberlite, possible kimberlitic rocks or evidence of significant alteration that could indicate a proximal intrusive body were identified. Anomalous KIMs were identified in drainage samples taken in the Radford Creek catchment, at Round Hill and west of the Boolcunda Basin, where multi-grain and multi-mineral (picroilmentite-pyrope-chromite) anomalies were detected in almost 50% of the samples collected. However, a high proportion of the recovered grains showed evidence of significant wear, interpreted as indicating a potentially distal or secondary source. In January 2004 FDL contracted Grant Boxer, a consultant geologist with over twenty years of international diamond exploration experience, to undertake an independent review of the Springfield Project and make recommendations on future work. Mr Boxer concluded that the majority of FDL's KIM anomalies were probably complicated by complex secondary dispersion from their primary sources. Two key recommendations from his review, that led to changes in exploration focus, were: - that diamondiferous kimberlite dykes represent a good target for a small diamond company, and therefore FDL should examine the potential for undiscovered diamondiferous kimberlite dykes in the Eurelia area; - that FDL should re-focus priorities from KIM sampling techniques to greater use of magnetics as a primary targeting tool. Justification for more direct use of magnetics was based on the fact that some of the Eurelia dykes (discovered by Stockdale using traditional KIM drainage and loam sampling in the late 1970s) could be identified as positive linear magnetic features in FDL’s 2003 Eurelia (100 m line spaced) aeromagnetic survey data. This implied that previously undiscovered kimberlite dykes in the region could be discovered with good quality aeromagnetic data. These kimberlites had initially been discovered by traditional KIM drainage and loam sampling with back up ground magnetics, VLF EM, soil and stream geochemistry, drilling and trenching. At that time, the Eurelia dykes were categorised by Stockdale into three distinct groups based on their kimberlitic indicator mineral (KIM) assemblages and diamond content, indicating three different phases of intrusion. Group 1 comprised the K1, K2, K3, K8 and K9 kimberlites; Group 2 comprised K5 and K6; and Group 3 comprised K4, K7, K12 and K13. The sampled Groups 1 and 3 intrusions are diamondiferous (but apparently uneconomic), and Group 2 is barren. Stockdale acknowledged that there were indications of additional kimberlites that were not located during their work (cf. Env 3891). FDL’s new exploration model, therefore, was based on the premise that probable ‘undiscovered’ kimberlite dykes near Eurelia and along trend within the surrounding region could be parts of additional phases of intrusion that might be economically diamondiferous. Existing aeromagnetic data was used to identify new kimberlite dyke targets, which were then profiled with ground magnetic surveys to define those having prospective magnetic signatures. Subsequently, shallow aircore drilling and/or excavation of trenches was undertaken to try to locate kimberlite bodies. Subsurface rock samples of ~50 kg were sent off for laboratory processing and scrutiny, to look for microdiamonds, to determine indicator mineral geochemistry, and to conduct whole rock and trace element analyses. During the period March 2004 to December 2005, FDL conducted 149 ground magnetic surveys in the Eurelia district which were followed up at selected sites either by trenching or by shallow aircore drilling in places where the cover was thought to be >5 m thick. 72 trenches were excavated at 35 ground magnetic anomaly sites, while at another 14 such sites, 39 vertical and inclined aircore holes were drilled for a total penetration of 768.1 m. This work resulted in the discovery of 16 new kimberlite dykes, while a further 5 buried kimberlites were inferred from subsurface sampling of their clay alteration zones. Of the 16 new kimberlites directly encountered, 6 were found to be positive for carrying microdiamonds. Prior to 2005, a small ~300ml sub-sample had been taken from the 20 kg bulk sample in the laboratory, and only that was tested for kimberlite indicator minerals. From January 2005, a separate (additional) 1 kg sub-sample was submitted to the laboratory specifically for macro / microdiamond and indicator mineral analysis, in order to collect a suite of characteristic kimberlite indicator minerals (KIM) associated with individual kimberlites. FDL planned to undertake a programme of bulk sampling in 2006 that would include some of the microdiamond positive kimberlites, in order to test those dykes for macro diamonds and also to gauge the reliability of using such a bulk (20 kg) microdiamond sample to selectively identify potentially diamondiferous kimberlite rock, instead of resorting to the traditional much larger 100 kg bulk sampling method that had been used previously by Stockdale to gauge the diamond potential of any newly discovered kimberlite.