Three-dimensional reflector imaging of in-mine high frequency crosshole seismic data

Abstract

A combined crosswell and VSP seismic reflection experiment was carried out in a metalliferous mine in an attempt to image in three-dimensions the stope tunnels and residual ore. The experiment provided initial field testing of a newly designed hardware?software system for high resolution in-mine seismic work. High frequency (1?3 kHz) seismic signals were recorded on both hydrophones and triaxial geophones from detonator explosions. The major form of noise contamination was tube-waves. The data were migrated in 3-D by forming a partially coherent sum of the cross-products (semblance) between the components of the particle motion vector and the components of the wave vector, over all receivers and all sources, for every grid point in the investigated volume. Migration maps with the PP mode using the crosshole data were the most successful. The images correlated remarkably well with the known geology and mineworkings.