British try new way to find faults : Heywood, P Coal Age, V87, N7, July 1982, P114–118

Abstract

Describes how Britain's National Coal Board (NCB) is taking seismic surveys from underground locations to get better information on faults so panels can be designed to produce more coal. Bounding shock waves along coal seams is expected to help the NCB to avoid sudden shutdowns of longwall faces. Because British coal seams lie far below the surface, surface seismic surveys only show major faults with throws (displacements) of several meters. NCB's underground surveys are picking up smaller discontinuities that would have gone unnoticed but are just as important. While seismic work is increasing, NCB is aware of its limitations: other sources underline that discontinuities are rarely simple faults; other seismic features can confuse maps; and the rebound from the first fault can hide further problems behind it. Some of these snags may be overcome with NCB's guided drilling technique, in which the drill skims along at a constant distance below the seam roof monitoring its position. Seismic surveys will provide a picture of general geology and drilling to targets identified in the survey will pin down exactly their locations and size. The holes could be drilled past the first fault and transmitters could be installed at their ends to provide more » a new perspective for seismic work. NCB mining consultants have helped start similar work in the US, and in return, the NCB is learning from the US how to interpret longer-length shock waves to locate shallow coal for surface mining. « less