Exploration of an area located 30 km south-west of Port Augusta initially sought possible Olympic Dam style iron oxide-hosted copper-gold deposits within concealed Mesoproterozoic basement, plus Mount Gunson style stratabound copper in the overlying Adelaidean strata. The latter objective has local substance in the form of the buried Myall Creek copper sulphide occurrence discovered in 1975 by Australian Selection Pty Ltd, which comprises interbeds of sandstone and dolomitic shale containing sub-economic copper (+ minor lead-zinc) mineralisation that is covering an area of about 3 km x 15 km at the base of the Adelaidean Tapley Hill Formation. Merritt Mining in 1998 concluded that the Myall Creek mineralisation is probably an epigenetic deposit derived from a nearby basement source, perhaps by leakage upwards along basement-penetrating faults. That company also identified mineralised pebbles in Backy Point Beds underlying the Tapley Hill Formation. These appeared to be eroded from a nearby basement source. After an initial geophysical assessment involving the merging and re-processing of existing airborne magnetic survey data, a ground gravity survey was conducted by EL 2800 licensee Minex in the Myall Creek vicinity during late November 2001 (208 stations at 1 km x 2 km spacing along 7 N-S lines) to help define structural lineaments interpreted from the aeromagnetic data, and to model possible dense basement targets for epithermal mineralisation. The survey results disclosed a NW-SE trending gravity ridge within the interpreted deep graben of Adelaidean sediments that underlies the Myall Creek prospect. A regional licence joint venture was entered into with Eagle Bay Resources NL on 15/11/2002, to progress exploration both on Tregalana and the adjoining Cultana tenement to the east. In December 2002 Eagle Bay performed a detail infill ground gravity survey at Myall Creek (677 stations on 19 E-W lines for a 500 m x 125 m station spacing), which resolved the gravity ridge anomaly into a more deep-seated source lying to the north-west, and a shallower one in the south-east. A consultant's 3-D inversion modelling of the gravity and magnetic data suggested that the latter anomaly could lie at a depth of about 205 m below surface, and was thus feasible to drill. A single RC/diamond drillhole was put down to 354 m total depth in May 2003 to test this gravity feature to see if it was the older primary basement source for, in particular, the "pebble" copper mineralisation found at Myall Creek. However, hole TR7 encountered, beneath minor Recent sediments, only an un-mineralised sequence of Tregolana Shale Member, Whyalla Sandstone Member, Brighton Limestone Member, Tapley Hill Formation, Beda Volcanics and Backy Point Beds, and the inferred up-faulted Mesoproterozoic basement was not reached. Eagle Bay has since concluded that the gravity high probably reflects uplifted Beda Volcanics in a narrow northwest-trending horst formed by post - Adelaidean faulting. Because the postulated presence of IOCG mineralisation in the local basement is still unproven, further gravity and drilling work similar to that already completed is now being planned, to try to address the potential of the remaining licence portion and that of the associated Cultana tenement.