Open file company data, released since the previous MESA review (Yates, 1992) of exploration in the Palaeoproterozoic - Mesoproterozoic rocks on OLARY 1:250 000 map sheet (Olary and Mingary 1:100 000 map sheets), is dominated by the results of exploration for base and precious metals, especially stratiform / stratabound Broken Hill-style Pb-Zn-Ag in Bimba Formation and Upper Albite of the Palaeoproterozoic Willyama Supergroup, and discordant Cu-Au associated with granites, etc. The most significant exploration in this period was a detailed and extensive program by North Mining Ltd on seven Exploration Licences (ELs 1847, 1849, 1926, 1977, 1987, 2046; and 1928 on CURNAMONA), two held over Willyama Supergroup metasediments and granites of the Broken Hill Domain to the east, and five over Willyama Supergroup metasediments and granites of the Olary Domain to the west, extending north from the Barrier Highway to the northern limits of Palaeoproterozoic - Mesoproterozoic outcrop on CURNAMONA. Exploration included aeromagnetic interpretation and ground magnetics, extensive stream sediment, soil, and rock sampling, and RAB drilling (105 holes, total 1753 m) of geophysical and geochemical anomalies - especially those obscured by cover. North identified 30 geophysical and/or geochemical anomalies, and sampled or mapped about a dozen old mines or prospects. Follow-up ground magnetics and IP, followed by aircore drilling (110 holes, total 1104 m) at Junction Grid indicated a significant target with up to 2600 ppm Zn, 340 ppm Pb, and 26 ppb Au in pelitic/psammopelitic schists adjacent to the alteration zone over the magnetic anomaly, close to the upwards projection of the EM anomaly, indicating that the EM anomaly may relate to sulphides at depth. Sampling confirmed base and precious metal anomalism in Bimba Formation and Perryhumuck Formation, and confirmed anomalous Au (Cu) associated with discordant quartz veining. At Horse Paddock Grid, soil sampling indicated a 250-500 m by 500 m zone of Zn anomalism in psammopelites. Following a change in exploration objectives, North relinquished its Olary Domain exploration tenements, leaving much of the area with un-evaluated exploration potential. North's work confirmed the mineral potential of the Olary Domain, pointing to similarities with mineralisation at Broken Hill and on the Stuart Shelf, and indicated that detailed geological mapping, sampling and geophysics can generate significant targets. At Crockers Well - Jackson Hill, broadly spaced soil and stream sampling by CRA indicated low potential for base metals, uranium and diamonds (ELs 1748, 1750). Following regional stream and rock chip sampling near Boolcoomata - Mooleugore Hill (EL 1616) by Aberfoyle and Normandy, a vertical percussion hole at Shorts Dam, targeting weakly anomalous (Cu-Zn) Bimba Formation, failed to penetrate laterite. At Ameroo Hill - Antro Woolshed (EL 1700), BHP identified 4 potential geophysical and geochemical targets, indicating weak Zn, Pb, Cu and Au anomalism in Bimba Formation. Two RC drillholes intersected pyrrhotite-bearing zones with up to 2 m at 0.19% Zn. North of Mannahill, extensive sampling, ground geophysics and 188 shallow RAB holes by Placer Exploration Ltd (EL 1699) targeted base metal mineralisation in Willyama Supergroup magnetite-haematite albite gneisses. RC drillholes at Dead Horse prospect intersected Willyama Supergroup granite gneiss, quartz-feldspar-biotite-magnetite gneiss, and schist; minor sulphides were noted, with best results of 2 m at 0.56 g/t Au and 8 m at 0.4% Cu. In Broken Hill Domain metasediments to the east, drilling by Moonta Mining and A. Muir at Mutooroo Copper Mine indicated continuous, thin, low grade copper and gold mineralisation along a shear zone (EL 1596). To the south, exploration by BHP (EL 1637) then MIM (EL 1832) comprised re-assessment of prior work and limited geophysics and drilling at previously identified prospects. Between Mutooroo and Cutana - MacDonald Hill (including the Olary Domain - Broken Hill Domain boundary), no anomalous results were reported by MIM from RAB drilling in the surrendered portion of EL 1772. Adjacent to the south (EL 1810), ground checking and geophysics did not indicate suitable drilling targets.