Deep Underground Mines – Perfect Laboratories to Conduct in-Mine Seismic Experiments for Deep Mineral Exploration

Abstract

Summary To supply the raw material for emerging green technologies and sustain long-term global growth, minerals exploration programmes need to focus on a search for economically feasible deep-seated mineral deposits in brownfield areas such as deep underground active mines. This is particularly significant in Europe and Africa where shallow (< 500 m depth) deposits are almost mined-out and new deep (≥ 500 m) deposits may exist below surface mine infrastructures where new surface seismic surveys may not be possible. In this study, one of the world’s deepest mines, South Deep gold mine, is used as a laboratory to investigate if seismic instruments can be utilised in active deep underground mines as cost-effective and environmentally friendly tools for deep mineral exploration. We particularly focus on the delineation of structures and fractures that crosscut and displace the gold orebody above the tunnel floor (~3.0–3.5 km) using surface waves (SW) attributes, P-wave refraction tomogram and P-wave reflection seismics. We also address some of the challenges that are related to in-mine seismic surveys in active deep mines and provide guidelines that can be used for future in-mine seismic surveys in other mines in the world.