Group-Level Summary for Group: M2940/1 (ITEM 2404) Group Title: Lake Minigwal copper-uranium exploration A Numbers in Group: 11786, 11788, 12196, 12443, 12496, 13701 Exploration for Roxby Downs-style (Olympic Dam) copper-uranium mineralization. The Archaean basement is covered by Phanerozoic sediments of the (Permian Paterson Formation) Officer Basin. The TRs were taken out over large intense circular magnetic anomalies on the edge of a regional gravity high (BMR data). New magnetic data either yielded no substantial magnetic bodies (TR 8743H), or anomalies were caused by banded iron formation (TR 8742H), magnetite-bearing metagabbro and pyritic chlorite-apatite-ilmenite-magnetite schist ("...probable...magnetite ore of gabbro association"), mica-quartz-diorite (TR 8744-8746H), or magnetic dunite (TR 8741H). None of the anomalies "...was found to be indicative of the Olympic Dam style mineralization or environment." The serpentinized and adcumulate-textured dunite (TR8741H), part of a mainly concealed (minor amphibolite and banded iron formation outcrop only) Archaean greenstone sequence, assayed up to 5800 ppm nickel. Petrographic studies indicated no relict primary sulphides and "...nickel is now hosted by serpentine phases and by goethitic iron oxides." "One sample analysing 1.1% nickel is believed to be associated with secondary enrichment processes". Euhedral grains of primary chromite/spinel are common...Secondary sulphite minerals include pyrrhotite and rare chalcopyrite and pentlandite...". Due to physical restriction on drilling (overlying unconsolidated sands) large parts of the intrusive have been left unexplored and "...The Minigwal dunite, by virtue of its size and clear definition of a model for dunite-hosted nickel mineralization, remains an attractive exploration target." Geophysical data from TR 8744-8746H indicated anomalies, similar to those caused by kimberlites or pipe-like igneous intrusions. Drilling results indicate that "...although several of the magnetic anomalies have been shown to reflect the presence of the pipe-like mafic to ultramafic intrusions, none has been shown to be kimberlite or of kimberlitic affinity." Prospects: Lake Mingwal Assays: