Geophysical Technologies for Detecting Underground Coal Mine Voids:
An Interactive Forum
High-Resolution 3D Surface Seismic Method and Former Coal Geophysics Program of a US Coal Company
Presenter: Lawrence M. Gochioco
Firm/Organization: GX Technology Corporation
Mailing Address: 5847 San Felipe Road, Suite 3800
Houston, Texas 77450
One of the best kept technology secrets in US coal mining history was that there was once a robust coal geophysics program that was fully utilized by a local coal company to detect and map various geologic anomalies and man-made structures ahead of mining. Several original mine plans were changed as a result of findings from seismic data that indicated the presence of geologic anomalies in reserve areas that could adversely impact future mine development and longwall production. By combining the surface seismic and exploratory drilling methods, the coal company was able to properly leverage its risk by gathering a lot of useful subsurface information ahead of mine development.
A case study is presented to demonstrate how this useful geophysical technology was used to gather valuable subsurface information that could impact future mine development. A high-resolution 3D surface seismic survey was conducted in 1989 over a reserve block where drilling indicated the presence of a potential geologic anomaly, called a roll. Since the survey was conducted years in advance of mine development, the unpleasant survey results provided CONSOL ample time to proactively develop appropriate alternative mine plans to address the future mining challenges. Thereafter, longwall production in this reserve block went smoothly with minimal problems.
From 1985 and 2000, I developed and directed CONSOL's multi-faceted coal geophysics program used to address various exploration, engineering, and environmental challenges. When all the former Conoco executives at CONSOL retired, the coal geophysics program became a victim of a reorganization plan in 2000 under the new management. With no geophysical technology in place, CONSOL stepped back to its old traditional drilling method of evaluating reserves, and with great hope (and luck) that drilling would be able to detect geologic and man-made anomalies.