b'AEGC 2023Short abstractsequipment, solar panels, electronics, batteries and many otherlayer typically found at the base of iron-rich detrital cover. A industrial applications hence the minerals containing thesesurface to the top of this anomaly was generated to assist with metals are on high demand. hydrogeological conceptualisation/ modelling of different MAR scenarios.Spodumene is the most valuable Li-bearing mineral present in the LCT pegmatites. Complex mineral intergrowth relationshipsThe magnetic datasets were re-gridded, merged, filtered, and and the presence of deleterious elements must be wellimaged. Key structures were then mapped from both the understood to achieve high lithium grades in the final product. magnetic imagery and AEM derived depth-slices and iso-surfaces.Copper and nickel are commonly extracted from the sulphideThe 2D seismic section revealed a syncline-like feature in the minerals which are typically finely dispersed in large ganguecover-metasediment contact, the location of which coincided minerals. In order to predict behaviour of the ore minerals inwith an important structure identified in the EM and magnetic the processing plant, the physical properties and the elementaldatasets, implying that the contact has been preferentially content of all minerals is investigated. eroded along the structure.Laser Induced Breakdown Spectroscopy (LIBS) from ELEMISSIONThese results ultimately translated to a reduction in required allows for a rapid and accurate quantitative mineral analysis ofexploratory hydrogeological drilling to the effect of ~$500k, large sample specimens including drill cores, rock chips and~240 hours hazard exposure, reduced land clearing, and sand fractions (+/-1mm). Unlike the X-ray based techniques,brought forward the timing of the knowledge acquired as the LIBS can directly identify the areas enriched in lithium andexisting datasets did not require lengthy land access approvals.define which minerals contribute to the Li concentration in the analysed samples. LIBS is also suitable for fast identification of gold, the platinum-group metals and the sulphide minerals.Groundwater geochemistry as exploration tool By understanding the mineral assemblage, informed decisionsthrough cover.can be made about the origin and extraction of the valuable minerals. Joseph TangTIMA automated mineralogy X-ray based technique fromGeological Survey of QueenslandTESCAN is commonly used for the mineral liberation studiesGroundwater chemistry is influenced by its contact with host of the crushed ore and metallurgical stream samples. Therocks and reveals information on lithology, alteration, and acquired X-ray spectra are compared with a pre-definedpotential mineralisation. It is a prospective exploration tool mineral library that includes spodumene, sulphides and manythat samples a derivative of the subterranean geochemistry, other minerals. Quantitative mineralogical data includes thewith effectiveness of its application for mineral exploration mineral mass distribution information, mineral grain size,depending on: (a) The availability of boreholes and borehole elemental deportment and the mineral liberation statistics. Thisdensity; (b) Boreholes with appropriate depth of penetration; information is used to optimise process flowsheet for griding,(c) Hydrologic connectivity of the country rocks; and (d) The flotation and leaching strategies to get the best quality product. availability of a regional hydrogeochemical baseline, to define chemical anomaly.An integrated geophysical method approach toMinerals react with groundwater and the metal solutes can evaluating managed aquifer recharge potential in thebe transported considerable distances from their sourcing Pilbara. ore bodies. Solubility depends on the physiochemical conditions of aquifer, with solutes typically in very low Nathan Tabain and Nicholas Quaglia concentrations at levels of parts-per-billion. The highest BHP Iron Ore concentrations of ore-related trace elements tend to be restricted to within 25 km of a metal source and tail off A small detrital basin located in the Pilbara, WA was identified aswith distance from the source, although their distribution a potential site for Managed Aquifer Recharge (MAR) of surplusis modified by groundwater flow. Isotopic analyses for18O, water generated from nearby BHP mining operations.2H and Pb isotopes are useful for determining source To initially assess the potential of a site for MAR, aregion, with the latter applied to fingerprinting a source hydrogeological conceptual model is required, along withregion, e.g., Proterozoic mineralisation.a subsequent exploration programme to test key targets.Hydrogeochemical interpretation applies a variety of Traditionally these objectives are primarily met by exploratorytechniques: (a) The direct statistical analysis of a single element hydrogeological drilling to identify the depth to target injectionconcentration is employed for metal prospectivity for Cu, Pb, Zn, stratigraphy, the location of major structure and dykes, and theNi, Co, Pt, Au, Ag, etc., by comparing the element concentration thickness and potential clay-rich inclusions of detrital cover. to its regional-background value; (b) Assessment based on a There was limited historical drilling available at the targetcombination of elements (also known as Specific Mineralisation location. However, several existing geophysical datasets wereIndex), a robust technique that uses prior knowledge of known identified as covering most or all the target detrital basin. Thesemineralisation models to predict mineralisation types, e.g., consisted of an open-file airborne TDEM dataset (XTEM), variousNi-Co-Pt for NiS systems; Zn-Cu-Pt-Ag for VMS deposits; and mostly open-file airborne magnetic datasets, and a short 2DAu, Ag, As, Mo, Sb for lode-Au deposits; and (c) Interpretation seismic test line dataset. of undercover geology using multi-element indices: Higher Cr and V concentrations are indicative of mafic rocks; higher U, of The XTEM data was inverted, and a conductivity volumegranitic rocks; and B/Na ratios used to differentiate between generated. This dataset identified the basal clays, a clay-richmetamorphic and sedimentary terranes.143 PREVIEW FEBRUARY 2023'