Soil Geochemistry and Pathfinder Element Distribution Associated with the Hillgrove Antimony-Gold-Tungsten Deposit, New England Orogen, New South Wales

The Hillgrove mineral field, part of the New England Orogen, host’s gold, antimony and tungsten in the form of scheelite mineralisation in a number of structures. Mineralisation is hosted in the Girrakool beds, Hillgrove Plutonic Suite and Bakers Creek Diorite Complex. Commercial mining of antimony has been undertaken on numerous occasions since its discovery in the late 1800’s, without long-term success. Straits Resources Limited undertook large-scale soil sampling of their exploration tenements, a subset of their data was provided for analysis. The majority of samples, within the study area, a sheep farm adjacent to the town of Metz, were acquired from soils derived from the Girrakool beds. Statistical analysis identified antimony and arsenic as the two best pathfinders for gold. Arsenic, mercury and gold were discovered as the best pathfinders for antimony and mercury was also found to be a pathfinder for tungsten. Acceptable maximum thresholds in the O horizon for the trace element concentrations of gold (0.0025 ppm), antimony (22 ppm) and tungsten (0.65 ppm) as well as the pathfinders, arsenic (24 ppm) and mercury (0.11 ppm) were calculated. The distribution of trace element concentrations was mapped over the study area using the calculated threshold values to identify possible locations of mineral occurences. A potential stibnite vein was identified along the central western boundary of the study area, while high gold concentrations were identified in the south-east corner of the eastern sampling zone.