Delineating Structures Controlling Gold-Bearing Horizons Using 3D Broadband Reflection Seismic Data - A Case Study From the Witwatersrand Basin (South Africa)

The 3D broadband reflection seismic survey, acquired in 2012 over one of the South African gold mines in the Witwatersrand Basin, have significantly improved the imaging of complex fault networks that have direct impact on the future mine planning and design. The high temporal and spatial resolution of the broadband data enabled the optimum mapping of thinner target horizons and smaller faults, providing a more detailed understanding of the complex structural architecture of the zone of interest in the gold mine. Both shallow (100 – 500 m depths) and deep target horizons (1.0 – 4.0 km depths) appear more continuous and reveal numerous stratigraphic details that were not visible in the 1996 legacy 3D seismic data. This improvement in imaging is understood to be caused by customized broadband sweeps, high-density point sources and receivers, and wide-azimuth acquisition geometry; as well as advanced processing (e.g., 3D FKxKy filtering and 5D interpolation/regularization) and interpretation techniques (such as seismic attributes). These advances in acquisition, processing and interpretation techniques have the potential to offer solutions for other mining areas with similar complex geology, especially in deep South African gold and platinum mines.