2D forward seismic modelling at the Thunderbox gold mine, Western Australia, using laboratory petrophysical data.

Seismic methods are not widely deployed in the mining industry. However, the increasing interest in deeper gold deposits, especially in Australia where the deposits are concealed under a thick cover of sediments, makes seismic methods an appealing tool for gold exploration and mining planning due to their capacity to couple resolution and depth of investigation. At Brownfield gold deposits, such as the Thunderbox gold mine, seismic methods could be integrated with the existing geological knowledge of the mine to help establish new exploration opportunities that extend the known mineralization at depth. However, seismic interpretation remains largely speculative in hard-rock environments due to: (1) highly complex geologic structures, (2) scarcity of boreholes elastic logs, (3) poor database documenting the petrophysical properties of gold-bearing host rocks. In this study, we present a 2D seismic forward modelling of the Thunderbox gold mine, Western Australia that was built using 2D geological section of the mine along with laboratory petrophysical measurements performed on over 100 whole core samples from the mine. Laboratory measurements include bulk and grain densities, and ultrasonic P- and S-wave velocities at ambient conditions and under pressure. We found that the seismic reflectivity between the lithological units is low, except for the massive basalt and the talc schist (shear zone) that show a notable acoustic impedance contrast with all lithologies. Given that most of the gold-host rocks at the mine seem to be only economically mineralized when they are in the vicinity of the shear zone, the delineation of this structure at high resolution can be attractive for Thunderbox mine planning.