Seismoacoustic Monitoring of a Longwall Face Using Distributed Acoustic Sensing

Area of Science:

• Geophysics
• Mining Engineering
• Seismology

Background:

• Underground mines face hazards from dynamic rockmass failures.
• Seismic monitoring is common in hardrock mines but challenging in coal mines due to size, speed, and safety regulations.
• Existing monitoring struggles with the unique environment of longwall coal mines.

Purpose of the Study:

• To introduce a novel monitoring concept using distributed acoustic sensing (DAS) for longwall faces.
• To evaluate the feasibility of a DAS-based seismoacoustic array in an active underground coal mine.
• To assess the potential of DAS for understanding coal-burst mechanisms and associated risks.

Main Methods:

• Laboratory testing of acoustic sensor response.
• Deployment of a DAS array along an active longwall face.
• Recording and analysis of seismoacoustic data during mining operations.
• Comparison of in-mine DAS data with a surface seismic network.

Main Results:

• The DAS array successfully recorded seismic vibrations and acoustic waves within the mine workings.
• Waveform moveouts were clearly identifiable in the DAS recordings.
• The standard deviation of audio recordings emerged as a potential metric for quantifying burst damage.
• DAS data provided insights into both seismic and acoustic phenomena associated with dynamic failures.

Conclusions:

• DAS-based seismoacoustic arrays offer a promising new strategy for monitoring underground longwall mines.
• This technology can help understand coal-burst mechanisms and manage associated risks.
• Further improvements are needed for routine implementation, but the potential for broader applications in underground environments is significant.