Empire Metals Limited sent 29 samples for petrographic analysis and 16 samples for Tescan Integrated Mineral Analyzer (TIMA) analysis from samples collected from both RC and diamond drill holes. These samples represent a point sample from a known depth in a drill hole and the information generated is interpreted to provide a first order understanding of the geology and mineralogy at only very specific locations. Petrology and TIMA results illustrate that the dominant detrital grains of quartz and feldspar in the sandstones and conglomerate matrix show angular to sub-angular shapes, indicative of immature sediments that have not been extensively abraded but fairly well sorted and so are inferred to have been deposited in one relatively brief period of transport and sedimentation, possibly from a nearby source.

The quartz, feldspar and mica grains within the siltstones are angular to sub angular and also preferentially aligned. The sediments within the Yandanooka Basin have been highly altered by hydrothermal fluids, petrographic evidence suggesting two separate hydrothermal events that each caused significant mineralogical changes. The alteration paragenesis has been developed by detailed petrography and TIMA analysis on RC chips and slices of drill core.

This work shows the initial alteration fluid produced an assemblage of epidote-titanite-carbonate and chlorite. The geochemical signature of this hydrothermal alteration event is strong Ca-Ti-Mg-Al-Fe rich with elevated Co-Cr-Co-Cu-Ni-Zn indicting that the fluid interacted with a mafic source. The composition of the hydrothermal fluid is not yet understood but silica was readily available from the primary siliciclastic components and so wasn't necessarily introduced to form the secondary silicate minerals.

This initial alteration mineral assemblage was subsequently overprinted by an iron-mobile hydrothermal fluid which was notable for the formation of hematite, largely as replacement of the primary magnetite grains. Such an extensive marmatisation event indicates that the first alteration event may not have sealed off the porosity and permeability within the sediments, or that this later hydrothermal fluid may have generated its own permeability as a result of fluid- rock interactions. The hematite from this second alteration event has subsequently been altered much later to goethite presumably by recent meteoric ground waters.