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Real-time
seismic monitoring of a block-caving operation
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Operation
A permanent surface and underground installation
of seismometers communicates with the seismic
controller located on surface for real-time seismic monitoring
of the rock mass. A GPS timing module is used so that recorded seismic
data may be integrated with seismic data from another nearby system
for information about regional seismic events. The GS
data acquisition unit uses an internal GPS module to ensure
common time with the seismic controller.
Communications
The RS485 protocol is used here to minimise cabling
costs. With this approach multiple GS
data acquisition units can be daisy-chained together with inexpensive
2-core twisted pair copper cable. Repeaters must be used if the
distance between any two nodes exceeds 1.2km. Each link can support
up to 10 GS units. Alternatively digital radio communications may
be more cost-effective.
Seismic Sensors
Each GS data acquisition unit can monitor and
pre-process up to six seismic signals, in any combination of uni-,
bi- or tri-axial seismic
sensors. For each seismic channel up to 3 logical
channels may be extracted with GS technology. Both geophones
and accelerometers (piezoelectric and Force-Balance) are currently
supported.
Seismic Data Processing & Interpretation
The seismograms of every seismic event that triggers
multiple stations are transmitted to the seismic
controller and recorded on a user-specific computer on the Local
Area Network (LAN). The seismic event is automatically processed
and seismic source parameters including the location, time, radiated
seismic energy and co-seismic inelastic deformation are automatically
calculated. This data is confirmed later by manual processing with
the software packages JMTS
running on either Microsoft Windows or Linux computer. Spatial and
temporal trends made then be detected and analysed using the interpretation
package Jdi.
This page last updated: January
2007
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