As part of a search for possible high crustal level, Olympic Dam - type IOCG deposits hosted by Mesoproterozoic basement rocks, Eromanga Uranium undertook deep diamond drill testing of two large, semi-coincident magnetic/gravity anomalies recognised within its exploration licences located on the northern margin of the Gawler Craton, approximately 50 km east-northeast of Marla. The company made a successful application for part-funding of this work as an approved PACE Initiative Year 5 project (DPY5-7). Previous company drilling of the long-recognised bulls-eye geophysical feature at Welbourn Hill, comprising 3 percussion holes put down by Newcrest Mining in 1992, did not reach the intended target. The 8-9 mGal residual gravity anomaly has an associated magnetic high, the source of which is interpreted to lie at >1500 m depth, and to possibly represent a pipe-like mafic intrusive body. Eromanga Uranium's modelling and interpretation of earlier detailed gravity data acquired across the prospect by Commonwealth Aluminium Corp. and by Newcrest has revealed a 5 km long, north-west trending gravity high which lies parallel to a bounding fault on its northern side. There is also a deep-seated zone of twice background IP anomalism identified by Newcrest, which coincides with the gravity and magnetic anomalies. The concurrently investigated target anomaly situated to the east of Nicholson Hill is an elliptical magnetic feature having the interpreted appearance of an eroded pre-Mesozoic dome or volcanic complex, which is about 15 kilometres wide in its maximum (NW-SE) dimension. An infill gravity survey was acquired by Eromanga Uranium in late 2008 to try to resolve a surrounding broad, >100 square km regional gravity feature into a valid compact gravity anomaly, but this attempt proved inconclusive. During the period January-August 2008, three rotary mud - precollared, vertical deep diamond drillholes were completed as the PACE project commitment, for a total penetration of 2431.0 m, including 2004.6 m of HQ/NQ coring. The two PACE diamond drillholes completed on the Welbourn Hill prospect, although sited 800 m apart, encountered basically the same sequence of as yet unattributed basement rocks, i.e. highly sericite - chlorite altered, fault - displaced microcline - quartz - plagioclase - cordierite - sillimanite gneisses and quartz - plagioclase - microcline - biotite metasediments, frequently cut by thin carbonate veins and containing very minor haematite and trace sulphide mineralisation. The single PACE drillhole completed at the Nicholson Hill gravity anomaly did not reach its target. Basement was encountered at 48.9 m depth. The preceding cover sequence consists of thin Tertiary sediments, underlain by interbedded clays and clayey sands believed to be Cretaceous (oxidised Bulldog Shale). Diamond drilling was carried out through an extremely thick succession of dolomitic siltstones and shales, within which the hole was terminated at 793.47 m depth. It is likely that this sequence is Adelaidean (?Callanna Group). All of the drill cores were logged with a hand-held scintillometer to detect any gamma radiation, and were sampled at regular intervals for their petrophysical properties. Core samples were taken at 1-metre intervals for multielement and whole rock geochemical analyses, and selected other core samples underwent petrographic studies.