Towards direct detection of gold bearing rock formations from seismic data, St. Ives gold camp, Western Australia

Abstract

In 2004, Gold Fields Limited and Curtin University of Technology undertook a project to assess the feasibility of the application of high resolution reflection seismic for gold exploration in Western Australia. A large scale regional survey several years before had indicated that deeper structures can be successfully imaged with course seismic acquisition techniques. These surveys provided images on a regional and camp-scale only while shallower structures of direct interest to exploration remained unresolved. The acquisition of high resolution seismic intended to detect economically viable targets for mineral exploration, turned out to be not a trivial endeavour. Seismic lines which traversed over and along busy mine site roads, around restricted areas, and through irregular, jagged terrain result in crooked-line geometry, often saturated with ambient noise, and running in an unfavourable direction with respect to the dominant trend of the major structures. This creates out-of-plane reflections and limits the effectiveness of pre-stack and post- stack imaging techniques and severely affects the calibration with sonic logs. While mine-sites generally have an abundance of borehole drilling data, sonic logs are in sparse supply and often restricted to shallow depths by hydrocarbon standards (200-900 meters), which presents a difficulty for seismic data inversion and subsequent lithological interpretation.