Exploration carried out over a south-eastern flanking portion of the Peake and Denison Inliers has targeted possible large-scale Proterozoic ironstone-hosted Cu-Au deposits within a highly magnetic, multiply deformed and metamorphosed buried basement terrain having geophysical features similar in size and intensity to those existing on the Stuart Shelf around the Olympic Dam deposit. The licence partners have targeted potential IOCG deposits with attributes akin to Olympic Dam, Ernest Henry and Candelaria, viz. size (>500Mt), grade (>2% Cu equivalent) and depth of cover (<200 m). New work comprised the carrying out of 193.5 line km of grid-based ground magnetic surveys at eight aeromagnetic anomaly sites, plus acquiring a regional gravity survey during July-August 1998 (including 942 of 2177 stations for the entire project area, read at 1 km x 1 km spacing), and subsequently, the drilling of one vertical rotary mud/diamond cored hole to TD 355.3 m, to test a magnetic anomaly (#6, of 3750 nT magnitude, with a modelled source depth of 277 m) that coincides with a 6 mGal residual gravity anomaly, interpreted as peaking at a location 1.5 km south-west of Dampier Mining's previous WLE1a drillhole. The Umbum Creek drillhole reached actual basement at 292.5 m depth, and was terminated at 355.3 m depth due to high artesian groundwater inflows. The basement lithologies were an alternating sequence of grey, massive to weakly layered quartz-feldspar-magnetite+/_ amphibole+/_biotite rocks, and pegmatite/granite. Traces of chalcopyrite were noted in the drill core from 348 m depth to the end of the hole, associated with segregations or veins of feldspar-quartz-chlorite(after hornblende)-biotite-magnetite. Chlorite alteration of biotite and hornblende is common, plus sericite alteration of feldspars (which have a low K/Na ratio, indicating a predominance of albite). It was concluded that the hole had penetrated into a magnetite alteration system, possessing mineralogical properties, including an iron content of up to 13.7 % Fe, which were enough to explain the observed magnetic and gravity anomalies. The highest trace metal intercepts were 120 ppm Cu and 0.02 ppm Au. No further field work was conducted during 1999, while BHP Minerals sought a joint venture partner to assist with continuing exploration; this search was quickly successful, when Rio Tinto Exploration (RTE) signed a joint venture agreement over the Peake and Denison Project with BHP on 12/5/2000, agreeing that it would act as project manager/operator for ELs 2509, 2549, 2557, 2596 and 2620. RTE proposed to re-process the available regional geophysical surveys, and to compile a GIS-based digital synthesis of the results along with all existing historical exploration data, before moving on to align critical prospectivity factors with current IOCG deposit genetic research concepts. Promising basement alteration systems so identified would then be subjected to reconnaissance IP surveying, detailed gravity surveying over any targets identified from the IP surveys, and rotary mud/ diamond drilling of selected targets. During 2000 and 2001 RTE focussed most of its exploration effort within the larger Peake and Denison IOCG project area, testing large IOCG targets under shallow cover along the western margin of the Peak and Denison Inlier. During this period the main office-based exploration activities directed at EL 2509 included regional data compilation and interpretation. This work indicated that; i) there are small- to medium-sized IOCG targets in areas of less than 200 m of Phanerozoic cover sediments that remain to be tested; and ii) there are larger-scale IOCG targets at greater than 200 m depth that remain yet to be adequately tested. The range of IOCG targets identified all fell outside of key exploration criteria set by RTE, so none were of immediate interest to the company. During 2002 no additional exploration was carried out within EL 2509. The EL was packaged along with the adjacent Peake and Denison IOCG project tenements owned jointly by RTE and BHP-Billiton, and offered to interested parties as a farm-in opportunity.