Tunnels and Mines

Imaging Ahead of the Working Face with Seismic Reflection Tomography

Dr Bob Whiteley, Director, Resources Division, Coffey Geosciences Pty. Ltd.

Economic and safe rock excavation is critically dependent on detailed understanding of rock conditions beyond the working face. The latest advance has come in the area of seismic reflection tomographic imaging implemented from the opening during operations. The new technology allows three dimensional (3D) images of rock structure and condition to be rapidly obtained ahead of the excavation. The method is called True Reflection Tomography (TRT™) and is analogous to shining a torch beam into the rock ahead of the working face. Since its introduction last year TRT™ has proven to be an effective and non-intrusive tool for imaging ground features along and adjacent to tunnels and mine developments in complex geologic settings. Currently, TRT™ has an detection range of 50m to 120m along the alignment, and a peripheral range of 20m to 30m either side of the opening. The technology uses readily available acquisition equipment and a portable computer with specialist processing software, and represents a breakthrough in tomographic imaging for the mining and tunnelling industry.

Some recent projects will be discussed including the Northside Storage Tunnel in the northern suburbs of Sydney.

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