Two separate grouped licence areas located to the north and the south-southwest of Coober Pedy have been explored for possible large buried economic basement-hosted IOCG deposits that would be of interest to new SA mineral explorer Vale (the Brazilian-based major company active in the business of iron ore mining and development of other bulk mineral resources). Both areas had been sparsely explored previously, with very few basement-penetrating drillholes on record. Early in the preliminary phase of past exploration data gathering and review, Vale noted that high conductivity in the deep crust is present beneath EL 5226, based on PIRSA regional magnetotelluric survey data, that was interpreted to represent the effect of hydrothermal alteration / metasomatism from migrating fluids that had passed along structures vectoring through the Coober Pedy Ridge towards the Olympic Dam IOCG deposit. Additional support for having possible local genesis of IOCG mineralisation was provided by data from U-Pb geochronological studies undertaken in 2011 by Adelaide University Honours student Teena Rusak, who identified possible Hiltaba Suite age felsic leucocratic intrusive rocks within a mafic basement gneissic gabbro cored in CRA Exploration's drillhole DD87LR3, which contains traces of copper sulphides. During the first year of the project, the only field work performed was the acquisition of infill gravity data on EL 5226. 839 stations were read on a regular 500 m x 500 m grid during September 2013 by Daishsat, to complement the existing local 1 km spaced gravity coverage. Later modelling and interpretation of the new gravity data, in conjunction with re-processing of available regional aeromagnetic data, identified five coincident gravity/magnetic anomalous areas that could be conceptual drill targets. During the second year of the project, the only field work performed was the acquisition of infill gravity data on EL 5225. 1203 stations were read on regular 500 m x 500 m or 500 m x 1 km grids during August 2014 by Atlas Geophysics, as well as along 8 detailed traverses. Later modelling and interpretation of the new gravity data, in conjunction with re-processing of available regional aeromagnetic data, identified four high priority discrete coincident gravity/magnetic anomalous areas that Vale considered as prime IOCG drill targets. Other work performed during the year consisted of the re-logging of the geology of stored RC drillhole chips and stored drill cores from past exploratory holes retained at the DMITRE Glenside Core Library, in conjunction with taking major rock unit magnetic susceptibility measurements and making 601 portable XRF spectroscopic geochemical scans. This work involved nine historic drillholes, and led Vale to make the following conclusions re. the EL 5225 area: - chalcopyrite and trace bornite identified in diamond drill cores indicates that Mesoproterozoic hydrothermal activity has taken place on the Mabel Creek High; - magnetite and haematite are also present in drill samples, however not in significant proportions; - alteration to albite, K-feldspar, scapolite, haematite or magnetite was observed in the Marathon Exploration MN series diamond cores, which denotes key proxies relating to IOCG prospectivity; and - evidence for a complex structural/tectonic history of deep burial, compression, uplift, possible extension and minor hydrothermal brecciation was interpreted from drill samples wherein kyanite, sillimanite, one instance of ptygmatic folding and pyrite-rich brecciation were observed. During the third year of the project, the six preferred drilling targets were further modelled using revised parameters, and five were confirmed for drilling in 2016. Two are located on EL 5225, two on EL 5513 and one on EL 5517. During the fourth and final year of the project, in the period May through August 2016, Vale completed exploratory RC drilling of 5 vertical holes for a total penetration of 1357 m. The company was aware of likely difficulties it would have in the field, identifying protoliths in such high-grade metamorphic terranes, and therefore while drilling it made concurrent use of good quality petrological examinations of 10 drill cuttings samples of the basement rocks to define retrograde and prograde mineral phases, as well as to identify ultrafine alteration and ultrafine mineralisation which are invisible under a hand lens. Subsequently, 480 basement drill cuttings samples were sent for laboratory whole rock multi-element assaying. The resulting rock geochemical data were interpreted by Vale's in-house experts using statistical data correlation computer algorithms and various element distribution plots. Rehabilitation of the five 2016 exploratory drill sites was completed by Vale prior to rig demobilisation. Hole GAWRC007 was drilled to test the central gravity feature of the Harlequin target on EL 5517, which was modelled as having the shallowest source depth of the three gravity highs within this prospect area. Basement was reached at a shallower depth than expected, at 185 m, and the hole was abandoned at 195 m due to difficult drilling conditions. This hole encountered a banded, fine to medium grained meta-amphibolite rock, probably a meta-gabbro diorite, which adequately explains the modelled target. Magnetic susceptibility and bulk density values that were measured from the drill cuttings are only slightly elevated with respect to background readings. The bulk density of the basement lithology averages 2.7 g/cc, and a weakly elevated magnetic susceptibility of 15 x 10-3 SI (average) was measured in the final 10 m drilled. The rock mineralogy was interpreted as reflecting distal IOCG alteration. Peak prograde regional biotite-andalusite facies metamorphism has in part been tectonically and hydrothermally retrogressed to illite-chlorite facies. Hole GAWRC008 was drilled to test the IOCG potential of a moderate to strong elongate gravity high with a surrounding zone of high magnetic susceptibility located in the NW corner of EL 5225, which Vale thought might suggest a zonation from magnetite dominated to haematite dominated alteration. Bulk density data measured from drill cuttings matches well with the modelled data and the bulk density of the basement lithology averaged a moderate 2.84g/cc. Magnetic susceptibility data from the upper section of the basement averaged 20 x 10-3 SI and was in agreement with the modelled values. However magnetite destruction deeper in the drill hole returned magnetic susceptibility values much lower than those predicted by the modelling. Basement was reached at 188 m, within the estimated depth range, and the hole was continued to a total depth of 360 m. Vale found that the alteration zonation it had interpreted from the potential field data as being magnetite and haematite was absent: instead, sample petrology actually revealed a variably retrograde, hydrothermally overprinted, metamorphosed and metasomatised, fine to medium grained mafic to intermediate igneous rock with an interbedded similarly altered and overprinted ultramafic igneous rock. Although ultramafic rocks are known to host nickel-copper mineralisation, the ultramafic unit encountered in this case was not considered prospective due to the high metamorphic grade. Trace metamorphic chalcopyrite was observed in the intermediate igneous rock, however. Hole GAWRC009 was drilled to test a strong gravity high in the NE corner of EL 5513, that is flanked by elevated magnetic response to both the east and north-west. Modelling of the available data indicated that the density anomaly is associated with a deeper coincident magnetic body. It was postulated that this deep magnetic feature might represent a large intrusion from which a higher level mineralized breccia system could have been sourced. Bulk density data measured from drill cuttings from GAWRC009A matched well with the modelled data, and the hole was considered to have adequately tested the target. The bulk density of the basement lithology averages 2.9 g/cc, and an elevated magnetic susceptibility of 100 x 10-3 SI (average) was measured in the final 36 m of the hole. This relatively high magnetic susceptibility does not match well with the modelled data, but the discrepancy was not considered significant. Basement was encountered shallower than prognosed, at 162 m depth. The hole was continued to a total depth of 334 m. It penetrated a strongly retrograde altered, metamorphosed and metasomatised magnetite bearing mafic igneous lithic clastic rock. Vale thought that the weak magnetic signature of the rock could be explained by prograde metasomatism which has altered the primary magnetite to sphene and amphibole. This model would explain the increased amplitude of magnetic and gravity signatures at depth as alteration decreases. Although K feldspar is present and is impregnated with ultrafine haematite, as well as chalcopyrite, such alteration was not considered to be a vector voluminous enough to indicate proximity to a large hydrothermal system like an IOCG system. The target of hole GAWRC010, located towards the SW corner of EL 5513, was an elongate ESE trending body with a very strong, coincident high magnetic and gravity response. Modelling of the available magnetic data suggested a high magnetite content in the order of that expected from BIF; however, the response could also represent a possible IOCG signature. Modelling of the geophysical data indicated a depth to target of roughly 100-150 m. Hole GAWRC010A reached basement at 159 m hole depth, slightly deeper than prognosed. Magnetic susceptibility and specific gravity values measured from drill cuttings matched the modelled data well, and the hole was considered to have adequately tested the target. The average bulk density of the basement is 3.2 g/cc, while its high average magnetic susceptibility of 430 x 10-3 SI matches the logged mineralogy. The target lithology was identified as a mafic, lithic, silty sandstone with abundant magnetite. This rock is strongly metamorphosed and metasomatised, and Vale considered that it is possibly best categorised as metamorphosed ferruginous silt/sandstone or BIF. Hole GAWRC011 was drilled to test a target located near the centre of the northern boundary of EL 5513, where a moderate strength, coincident gravity and magnetic anomaly extends towards the NE. Magnetic susceptibility modelling suggested a dip towards the north, but that inferred structuring was seen as ambiguous in the coarse gravity data. Drilling was proposed to test the highest modelled density contrast within this feature; available geophysical data defined an estimated depth to the target of 180-230 m. Basement in hole GAWRC011A consists of a mafic sediment which was penetrated at 199 m depth. The average bulk density of the sediment is 2.8 g/cc; its moderate magnetic susceptibility of 16-36 x 10-3 SI fits with a mineralogy comprising abundant hornblende, magnetite and clinopyroxene. Vale considered that a high degree of retrograde hydrothermal alteration focused along structural corridors may be causing the observed regional gravity signature. Trace chalcopyrite of interpreted prograde metamorphic/metasomatic paragenesis occurs as inclusions within and also interstitial to amphibole, pyroxene, magnetite, biotite and plagioclase. In places it has a close spatial association with very fine to ultra-fine grained graphic intergrowths of magnetite and amphibole. The technical results of the above drilling program were generally regarded as discouraging. No significant IOCG style alteration had been encountered at any of the targets, and final assay results returned no anomalous values for copper, gold or IOCG pathfinder elements. Vale now felt that a key shortcoming with respect to the prospectivity of the project area was an apparent absence of voluminous Hiltaba Suite rocks or breccia systems, since the lithologies it had encountered are dominated by metasediments of mafic igneous provenance which have become regionally metamorphosed at amphibolite-granulite facies grade. The single ultramafic rock unit which was encountered during drilling had some properties which also suggested to Vale that this basement terrane would be unsuitable for the emplacement of intrusion related nickel-copper mineralisation. The company believed that no other viable targets remained to be tested on the project ground, and therefore decided to surrender tenure.