A 32-channel PSS seismic monitoring system was commissioned at Mt
Charlotte mine in 1994, and at the time it was the first such system in
Australian mines. The system continuously observes the occurrence of
seismic events and locates them accurately in space and time. Mt
Charlotte has a history of seismicity, with the largest event in recent years
of Richter magnitude 4.3. The decision to 'go seismic' was made despite
some uncertainty regarding its potential usefulness. However after the
first year of operation, benefits have been realised in terms of less
production downtime, improved mine safety and mine planning, and
better understanding of the nature of Mt Charlotte seismicity. The seismic network has performed well, recording 550 events in its
first year of operation to a location accuracy averaging 12 metres.
System reliability is excellent, with very little downtime, and acceptable
operation and maintenance times and costs. Observations show major
distinct changes in the rate of mining induced seismicity over time
periods of weeks and months. Events have tended to cluster in specific
mine areas and on particular faults and structures. Case examples of
pillar preconditioning, breakout around an orepass, and a major stope
rockburst, illustrate the role of seismic data and the benefits it brings to
safety, productivity and planning.