Title page for ETD etd-05132006-081141


Type of Document Master's Thesis
Author Yancey, Daniel Jackson
Author's Email Address dyancey@vt.edu
URN etd-05132006-081141
Title Analysis and Application of Coal Seam Seismic Waves for detection of Abandoned Mines
Degree Master of Science
Department Geosciences
Advisory Committee
Advisor Name Title
Imhof, Matthias G. Committee Chair
Hole, John A. Committee Member
Snoke, J. Arthur Committee Member
Keywords
  • void detection
  • seam waves
  • mining geophysics
  • dispersion
  • guided waves
  • coal seam
Date of Defense 2006-05-01
Availability unrestricted
Abstract
It is not uncommon for underground coal mining to be conducted in the proximity of abandoned underground mines that are prone to accumulate water, methane or other toxic gases, and are often either poorly mapped or without good surface survey control. Mining into such abandoned voids poses a great safety risk to personnel, equipment, and production from inundation or toxic/explosive gas release. Often, surface or underground drilling is employed to detect the mine void and evaluate the hazards, sometimes with disastrous results. The use of guided waves within coal seams can be utilized to locate voids, faults, and abrupt seam thickness changes. The use of seam waves for void detection and mine planning has tremendous value and use.

To demonstrate the feasibility of abandoned mine void detection utilizing coal seam seismic waves, two in-seam reflection surveys and a transmission survey were acquired at an abandoned underground mine near Hurley, Virginia. Numerical modeling of the seam waves was examined as well. The Airy phase was observed in the synthetic and real field data. Dispersion analysis of the field data shows reasonable agreement with the dispersion characteristics of the synthetic data. Using standard commonly available seismic reflection processing tools, a known and well-mapped mine was detected and located.

Detection of the mine with both surveys indicates that ``exploratory'' drilling can be replaced by noninvasive seismic methods. Location, however, was not good enough to replace drilling entirely. Hence seismic methods can be used for detection, but if a potential void is detected, focused drilling should be applied for accurate mapping and circumvention of potentially hazardous areas.

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