Final Report Geophysics and Drilling Collaboration Round 15 - 2022 Hayes Creek Drone Magnetics

Abstract

The Hayes Creek Project in the Pine Creek Orogen comprises the Fountain Head, Glencoe, Iron Blow and Mount Bonnie historic mines where PNX Metals have delineated base and precious metal resources and are working towards developing mines. Close-spaced drone magnetics was flown over these four deposits and their immediate surrounds to unravel the complex structural geometry of the host geology, image mineralised corridors directly and ultimately identify additional resources to enhance the project's economic base. The Hayes Creek deposits are located in a folded volcano-sedimentary package. The stratiform Iron Blow - Mount Bonnie gold-zinc-rich mineralisation is folded within the package, whereas the Fountain Head - Glencoe gold mineralisation is related to post-folding cross-cutting quartz veins focused near pre-existing anticlines. All mineralised lodes have then been faulted. All four deposits have very complex structural geometries. The existing magnetic data that cover these deposits are too coarse or noisy to resolve deposit-scale structural complexity. Finer scale data are required. Ground magnetics is impractical due to existing water-filled pits and so using a drone to fly detailed magnetic surveys was trialled. Drone magnetics is an adaption of two recent technological advances - drones and smaller magnetic survey equipment. The drone magnetic survey was undertaken by SensorEM using a DJI Matrice 300 drone with a Geometrics Magarrow. A GPS base station was set up, so all data were precisely located. Prior to flying drone magnetics, a LiDAR survey was completed over both survey areas. The LiDAR produced a very detailed Digital Terrain Model (DTM) which had two benefits; to better guide the drone to drape the topography, thus maintaining constant height, and better levelling of the magnetic data post survey. The LiDAR and magnetic surveys were completed in August 2022 under very good flying conditions. The data quality is excellent and a lot of detail can be seen in the imagery. Of greatest interest are north-trending lineaments which cut the Fountain Head and Glencoe deposits and extend between the deposits and beyond. These lineaments are defined by their low magnetic intensity cutting more magnetic units suggesting a process whereby the existing geology is demagnetized. These lineaments are parallel to gold-rich sheeted quartz veins at Fountain Head (Tally Ho gold lodes) and gold-bearing quartz veins at Glencoe. The demagnetisation is interpreted to be related to quartz vein emplacement and associated wallrock alteration. Furthermore, the lineaments appear to dislocate pre-existing magnetic features and are interpreted to be faults. There is a +1,200 m wide corridor within which Glencoe and Fountain Head lie where such faults are abundant, though individual faults can be traced outside this corridor. Folded stratigraphy between Fountain Head and Glencoe is also very clear. The magnetic intensity of these units suggests they are part of the Koolpin Formation. In short, the drone magnetics has identified numerous high priority gold targets. The folding and faulting at Iron Blow and Mount Bonnie are much clearer than in previous surveys. The prospective stratigraphy, which hosts the stratiform base metals lodes, can be traced confidently. Faults displace the stratigraphy in various geometries with some critical faults obvious near the known base metals lodes. There are a few direct base metals targets requiring further investigation.