488 square km of EL 5417, located ~95 km north-west of Ceduna within the Yellabinna Regional Reserve, and extending for between 5 km and 29 km towards the south-southwest from Mount Christie Siding on the Trans Australia Railway, have been relinquished due to their now perceived diminished prospectivity for containing magmatic Ni-Cu-PGE mineralisation within buried Proterozoic mafic and ultramafic basement rocks. Iluka Resources, through its New Commodities Div., had taken up this ground seeking to identify any basic igneous intrusions which might have undergone a magma evolution petrogenetic process of sulphur saturation : this being regarded as a key prospectivity indicator for the formation of copper-nickel massive sulphide mineralisation within magmatic cumulates related to enclaves in the feeder structures of Proterozoic mafic / ultramafic intrusions which were emplaced along craton margins, as has been repeatedly evidenced elsewhere in places where such deposits have been tested by historical percussion drilling, e.g. at the giant Voisey's Bay deposit in Newfoundland. From early in 2014, Iluka undertook regional geophysical surveys over its Eucla Project tenement holdings, which comprised airborne magnetic / radiometric / DTM surveys plus ground based electromagnetic (both MLTEM and FLTEM type) and gravity surveys. Interpretation of the geophysical data generated a few targets which were later tested by drilling, including one target that lay within the relinquished portion of EL 5417. Here a total of 13 vertical RC/aircore holes for 698 m were drilled into basement during early April 2016. However, no mafic / ultramafic rocks were encountered, which was disappointing. 44 x 1.5-metre depth interval samples of the basement lithologies penetrated were submitted for laboratory multi-element assaying. Another 92 drill cuttings samples of basement from 9 of the holes were spectrometrically scanned onsite using portable X-ray fluorescence equipment. The cover interval sediment samples from the holes were also inspected to look for any heavy mineral sands (HM) occurrences, but none were seen. It was concluded that the relinquished portion of EL 5417 did not exhibit the geological features expected to be associated with the accumulation of HM or of nickel, copper or platinum group element mineral deposits.