Early in 2001, Helix Resources Ltd entered into a joint venture agreement with Centrex Resources Limited to allow it to explore for precious and base metals on some of the tenements held by Centrex on the Eyre Peninsula in South Australia, including the subject EL 2815 Cockabidnie. Centrex retained the rights to all industrial minerals, iron ore and diamonds that might lie therein. Early in 2002, following initial 1:20,000 scale field geological/structural mapping and rock chip sampling (23 samples) of limited bedrock outcrops, a programme of calcrete geochemical sampling was commenced over subcropping Hutchison Group metasediments. 382 regional reconnaissance samples were collected along 800 m spaced lines at 200 m intervals. Follow-up infill sampling (248 samples) during August 2002, utilising a changed methodology for sample collection, tightened the sample spacing down to 200 m x 25 m, and delineated a significant 200 m wide and 2.5 km long Au+Cu+As+Zn anomaly. The peak gold-in-calcrete value was 57 ppb Au, with other element maxima being 306 ppm Cu, 502 ppm Zn and 295 ppm As. During November 2002, 31 RAB holes for a total penetration of 1740 m were drilled to test the abovementioned calcrete anomaly. This drilling gave disappointing results, encountering minor, low grade base metal mineralisation, but little or no gold mineralisation; however, several broad intercepts of silver were made from 1-metre resampling of 4-metre composite cuttings samples, yielding up to 63 ppm Ag. A series of chlorite-altered metasediments were penetrated, locally having graphite and iron sulphide replacing up to 100% of the host rock. Helix decided to withdraw from exploring the licence due to its perception of diminished copper and gold prospectivity there. During 2004, Peninsula Minerals Ltd entered into a joint venture agreement with Centrex in order to continue exploring EL 2815 for base metals. The company's primary aim was to delineate and test a regional gravity anomaly lying on the axis of the Cockabidnie Syncline. Previous exploration in the adjacent parts of the tenement had demonstrated to it that the hosting Hutchison Group metasediments are well mineralised, with better grades apparently related to secondary structures. A possible Broken Hill or Menninnie Dam type massive sulphide orebody was the objective. A gravity survey of the target anomaly was conducted during March 2004 to try to define its internal density distribution features, with 267 readings taken along 3 line pairs (pair separation 666 m) located 333 m apart, using 250 m and 100 m station intervals. After imaging of the corrected gravity data, the gravity anomaly was tested with a single inclined diamond drillhole, CBDH-001, which was terminated at 502 m depth without finding rocks that would adequately account for the gravity response. This drillhole encountered mixed calcsilicate gneiss, BIF and schist containing minor pyrite. A post-drilling analysis of the gravity data was performed by Peninsula Mining utilising 13 specific gravity measurements made on the drill core, with modelled gravity values being extrapolated accordingly across the spread of survey stations. This work indicated that the causative body to the target gravity high could have a steeply plunging pipe-like form, which would require the acquisition of additional detailed gravity data for better delineating its footprint and attitude. It appeared that the first test drillhole had been sited at least 100 m south of the axis to the modelled plunging causative body. During 2005, Centrex re-negotiated its joint venture agreement with Peninsula Minerals and resumed operating exploration on EL 2815. A comprehensive geophysical data interpretation was begun, principally to try to recognise the extent of and to help prioritise iron ore prospects. After the passage of another 20 months, Centrex and Lincoln Minerals decided to acquire and to share the cost of a low level detailed airborne geophysical survey which they believed should improve the resolution of their respective exploration targets. So during February 2007, UTS Geophysics was contracted to fly a multi-licence magnetic/radiometric/DTM survey at 100 m flight line spacing, of which 1934 line km covered the now renewed Cockabidnie EL 3609. Later, between May and August 2007, Lincoln Minerals conducted semi-regional, 500 m x 500 m and infill calcrete sampling over selected magnetic anomalies, collecting a total of 609 samples for assay. In two reconnaissance bedrock drilling campaigns undertaken on EL 3609 during September-October 2007 and March-April 2008, Lincoln Minerals completed 205 mainly vertical aircore and slimline RC holes for 7213 m. The first campaign, of 45 inclined holes for 3396 m, outlined a new lateritic/saprolitic nickel discovery along with base metal, gold and uranium mineralisation occurrences near Darke Peak. Significant results included a 4 m thick laterite grading 0.68% Ni, 0.05% Co and 0.03% Cu (19.95% Fe) above a 12 m thick saprolite zone grading 0.34% Ni, 0.02% Co, 0.02% Cu and 0.03 g/t Au (9.4% Fe) in hole CBAC044, while hole CBAC007 intersected 6 m @ 0.42% Ni, 0.06% Co and 0.02% Cu (11.25% Fe) from 21-27 m (ca. 18m true depth). The results from these holes drilled in 2007, combined with interpretation of aeromagnetic maps and calcrete geochemistry, identified a potential zone of lateritic nickel mineralisation extending over a strike length of at least 5 km. The mineralisation occurs at depths of about 15-20 m beneath shallow cover in the Campoona Syncline, and overlies fresh gabbroic amphibolite bedrock carrying up to 0.1% Ni. Lincoln Minerals regarded this discovery as very important because it demonstrates the presence of lateritic nickel mineralisation in an area of the Gawler Craton which had not previously been the target of nickel exploration. The second aircore drilling campaign outlined further lateritic/saprolitic nickel-cobalt mineralisation grading up to 1.15% Ni plus 0.045% Co, 0.037% Cu and 0.18% Zn (hole CBAC182, 25-26 m), and 0.33% Co plus 0.21% Ni and 0.07% Cu (hole CBAC185, 30-31 m). It disclosed significant intervals of mineralisation up to 30 m wide (CBAC185, 20-50 m @ 0.13% Co, 0.18% Ni and 0.05% Cu) where the Ni equivalent ore grade (Ni-Co-Cu), based on current world metal prices, averages about 0.8%. Because of the widely spaced drill lines, the mineralised 'pods' remained open both along strike and in some cases across strike. 10 cuttings samples were selected from holes drilled in the latter campaign and were forwarded to Pontifex and Associates for specific mineral identification in relation to nickel-bearing minerals. However, due to the high degree of weathering of the samples submitted, no nickel minerals were visible or otherwise detectable. It was speculated that the anomalous Ni assay values would most likely derive from nickel ions adsorbed onto saprolitic clays, especially the abundant and widespread smectite. Lincoln Minerals also collected some downhole bulk samples of saprolite, which it intended to use for a future scoping study to examine whether heap leaching of this material would be a viable method for extracting the nickel and cobalt that it contains. Within and immediately west of the Campoona Syncline, the reconnaissance drilling done in 2007 also revealed significant base metal, gold and silver mineralisation, returning best assay values of up to 2.4% Zn+Pb, 0.26 g/t Au and 26 g/t Ag. Other significant drilling intercepts obtained by Lincoln Minerals on EL 3609 include zones of elevated uranium up to 81ppm U (hole CBAC002, 28-29 m) below surface uranium calcrete soil anomalies. The uranium occurs in basement rocks that were originally not far below the Mesoproterozoic unconformity, similar to the setting of Alligator Rivers style uranium mineralisation in the Northern Territory. During September 2008, Lincoln Minerals re-assayed 575 old stored drill cuttings samples collected by CRA Exploration in 1981 during its RAB drilling of the Campoona Syncline. CRA's drillholes had ranged in depth from 4 m to 21 m, depending on where blade refusal occurred; the bedrock at the bottom of each hole had then been sampled for Bi, Cu, Pb and Zn assaying. The check and further analyses which were now done by Lincoln Minerals consisted of the elements As, Ca, Co, Cu, Fe, Mg, Ni, Pb and Zn, assayed by ICP-ME methods. This work returned anomalous nickel and cobalt assays of up to 0.16% Ni and 0.02% Co. During 2008-2009, Centrex performed detailed geological mapping and rock chip sampling on EL 3609 with a view to selecting drill sites for appraising the local iron ore potential. Regional stratigraphic and structural mapping which had been carried out by the SADM in the late 1950s, and data from a number of subsequent aeromagnetic surveys, had indicated that the BIF strata in the Campoona Syncline are prospective to host magnetite and possibly also haematite resources similar to those identified at Bald Hill and Koppio. As well, an east-west shear zone which SADM had mapped near the western boundary of the subject tenement area was recorded as containing two outcropping narrow, steeply dipping and parallel haematite veins that disconformably cut across the Mesoproterozoic Blue Range Beds. The thickest vein (seen to anastomose from 0.5 m to 4 m wide in places) was channel sampled by Centrex to determine the variability of its iron, silica, alumina and phosphorus content. In April 2009, Centrex planned to conduct an airborne gravity Full Tensor Gradiometer (FTG) survey across most of the licence area to assist with designing its drill programme. This survey was flown during August-September 2009 along 56 lines spaced 200 m apart, for 775 line km. A geophysical consultant's interpretation of all of the potential field data available to Centrex for the Campoona Syncline recommended 22 possible iron ore drilling targets accorded five priorities, with most targets probably lying at around 200 m depth or shallower. During January-February 2010, Centrex drilled 26 iron ore exploratory holes for 2406 m on EL 3609 to search for low-phosphorus haematite deposits which might yield blending feed to upgrade and complement ore for export that was planned to come from the company's nearby undeveloped Wilgerup haematite deposit. Targets tested were mainly those recommended by the GeoInterp consultant's report, plus drilling to probe beneath Centrex' previously mapped outcropping thin haematite veins. However, the drilling results at Cockabidnie proved to be disappointing, as no significant bodies of such mineralisation were encountered, despite the holes commonly intersecting ferruginous metasediments, schists and amphibolite within the oxide and primary zones. 268 bulk samples were taken from selected drillhole intervals for whole rock analysis, trace element assaying and Davis Tube Recovery tests (for magnetic mineral grains). The best intercepts made were 6 m @ 55.8% Fe in hole COR01 and 6 m @ 52.3% Fe in hole COR16; the best magnetite intercept was 10 m @ 22.5% Fe. In 2012, Centrex resampled old diamond core from the historic CRAE-Billiton drillhole DDHSC1 stored in DMITRE's Whyalla Core Library. Standard XRF iron ore assays and Davis Tube Recovery tests were conducted on 22 samples. During July 2012, Lincoln Minerals contracted Fugro Airborne Surveys to conduct an airborne transient electromagnetic survey totalling 445 line km at 400 m line spacing and nominal 120 m sensor height, which covered most of the renewed Cockabidnie EL4883. This survey was part funded by DMITRE's PACE Initiative in their PACE 2020 Targeting module that is managed by the SA Government in order to promote new mineral exploration technologies, and the operational procedures were reported by Lincoln Minerals in their PACE PT1-16 Final Report (see Env 12371) . The TEM data was merged with those obtained from earlier surveys of Lincoln’s neighbouring tenements, to yield a suite of conductive anomalies that could represent graphite targets. No field work took place on the licence area during 2011, 2013 or 2014. Midway through 2015 the joint venture decided to surrender tenure at Cockabidnie, as prospects being evaluated on their other Eyre Peninsula acreage seemed to offer better economic returns.