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Pure and Applied Geophysics

, Volume 164, Issue 1, pp 177–197 | Cite as

High-Frequency Hydroacoustic Monitoring in an Underground Iron Mine

  • Séverine BernardieEmail author
  • Jean-Pascal Gilbert
  • François Lebert
  • Hubert Fabriol
Article
  • 78 Downloads

Abstract

The monitoring of the stability of old mines constitutes an important research objective for our institution, BRGM. The study reported here shows the contribution of high-frequency (>30 kHz) acoustic emissions to the detection of the damage within a rock mass, during an experiment within a pilot site of an old flooded iron mine. The experiment consisted of recording all the hydroacoustic events in a broad frequency band (between 30 Hz and 180 kHz), during 18 months. The monitoring network has been calibrated by a triggered block fall that made it possible to highlight a relationship between the occurrence of high-frequency/low-frequency hydroacoustic emissions and rock falls. The events recorded have been associated with the micro-failure of the rock mass near the roof, prior to the detachment of the blocks. This monitoring showed important high-frequency hydroacoustic activity, which may be associated with mechanical instabilities generated by the evolution of water pressure during the experiment. In conclusion, the high-frequency hydroacoustic activity appears to be a good indicator of instability and, therefore, this new technique constitutes a promising tool for monitoring abandoned underground cavities.

Keywords

Hydroacoustic monitoring acoustic emission high-frequency signals mine rock fall 

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Copyright information

© Birkhäuser Verlag, Basel, 2007

Authors and Affiliations

  • Séverine Bernardie
    • 1
    • 2
    Email author
  • Jean-Pascal Gilbert
    • 2
  • François Lebert
    • 2
  • Hubert Fabriol
    • 2
  1. 1.Development Planning and Natural Risks DivisionBRGM 
  2. 2.Orléans Cedex 2France

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