Two adjoining areas located north of Koonibba were taken up to explore this part of the south-eastern Eucla Basin for possible buried economic marine placer deposits of heavy mineral sands (HM), because they were believed to contain shallow or exposed basement erosional features which might provide geomorphologic traps for HM. Also, gravity and aeromagnetic surveys conducted in 2010 had disclosed several anomalies within the Yumbarra Conservation Park, to the south of the Bay of Plenty HM depositional area, and it was thought by Iluka that these geophysical anomalies might possibly represent buried IOCG mineralisation occurrences. Magmatic nickel sulphide deposits, similar to the Voisey’s Bay style, were also believed to perhaps be present within sheared basement in these areas. Such deposits are related to the feeder structures of Proterozoic mafic/ultramafic intrusions which were emplaced along craton margins. Exploratory vertical aircore drilling was performed on both licences in 2013 to test for the presence of inferred marine foreshore sands deposited in a palaeogeographic setting behind the Ooldea Range. 74 holes for 3184.5 m were drilled on EL 5099, and 82 holes for 3167.5 m were drilled on EL 5100. The degree of sorting of beach facies strata encountered was encouraging, however, no significant HM were intersected within the foreshore facies sands. All holes were terminated once they reached lagoonal lignitic sediments underlying the sand units. On EL 5099, a best intercept of 1.5 m @ 4.7% HM was made in hole YE10761 at a depth of 88.5 m, but follow-up close-spaced drilling showed the occurrence lacked lateral extent, was too deep and was generally too low in grade to be considered viable. In 2014, Iluka undertook soil geochemical and biogeochemical sampling within EL 5099 to try to detect pathfinders to concealed nickel sulphide and other base metal mineralisation. An orientation survey over a known nickel anomaly consisted of the collection of 117 soil samples in three grain-size fractions and 43 biogeochemical samples. The sample assay results indicated that, in this region, biogeochemical sampling does not produce a meaningful reflection of basement and/or regolith geochemistry, as the method could not replicate Ni and Cu anomalies generated by previous work. Also during 2014, an airborne VTEM (virtual time-domain EM) survey covering 93.5 square km of EL 5099 was flown to look for bedrock conductivity anomalies. A number of these were identified which appeared to have signatures consistent with the presence of nickel and/or copper sulphide mineralisation. Targeted ground based survey follow-up using high-powered, moving loop TEM (MLTEM) and fixed-loop TEM (FLTEM) was carried out over the highest priority anomalies. No high order or well defined bedrock conductors worthy of further work were identified. In consequence of their now perceived diminished prospectivity for HM and other valuable minerals, ELs 5099 and 5100 have been fully surrendered.