Underground seismic reflection experiment in a gold mine

Abstract

An underground seismic reflection survey was carried out at the Revenge Gold Mine in the Kambalda area of Western Australia, in an attempt to map the shear-hosted ore lode. The experiment entailed 140 small explosions fired into a 47-element geophone array laid out along the floor of a section of tunnel. The target mineralisation was located approximately 100 metres below the tunnel floor. This was the first such experiment ever attempted in an Australian gold mine. The data quality was generally good, with 1?2 kHz signals propagating over distances of greater than 100 metres. Strong P and S direct arrivals were observed, but reflections from the shear zone were not found, even after CDP processing. One problem was sensor mount resonance. Another was the lack of target contrast and the rough/diffuse nature of the interfaces being mapped. The experiment demonstrated capability to retrieve high frequency seismic data under difficult circumstances. The experience should be beneficial to future reflection surveys in metalliferous mines.