Ore-body delineation using borehole seismic techniques for hard rock exploration

Abstract

Over recent years, seismic methods have emerged as a potential imaging technique for delineation of ore-bodies and for mine planning. The application of surface seismic methods in hard rock environments is however challenging due to various effects such as energy attenuation and scattering. Borehole seismic methods can be used to reduce these effects. The methods offer higher resolution at target depths, thus allowing better delineation and understanding of reflections from ore deposits. We present a synthetic study to understand the ability of the cross-hole seismic method to delineate ore bodies. Three variations of a simple scenario typical of nickel deposits found in the Yilgarn Craton were considered. Of the three models, two consist of volcanics overlying a granite body and a thin sulphide mineralized zone along the contact but at different locations relative to the source and receiver boreholes. The third consists of only the rock units with no sulphide mineralized zone along the contact. Synthetic shot records were produced and wavefield separated. Up-going wavefields were then used to create depth migrated images. The resulting images correlate well with the volcanic-granite contact and massive sulphide lens, showing the potential of using the cross-hole seismic method to delineate ore bodies.