1. Thank you BBUGS and BOHOGS for the opportunity to present today

2. Vibrating Wire Technology
What is it?

3. How does it work?
The resonant frequency of vibration of a tensioned wire is proportional to the strain or tension in the wire.
This fundamental relationship is utilized in a variety of configurations for the measurement of strain, load, force, pressure, temperature and tilt.

4. History of the technology
Vibrating wire technology has been around since early 1928 in France and Germany
The technology really advanced in 1954 when Telemac of France developed the twin coil sensor
Further refinement was developed by Irad then Geokon for the USA in the late 1900’s
Today the technology is well accepted throughout the world

5. Applications in UG Coal Mining
Roof & rib monitoring
Pore water monitoring
Pore gas monitoring
Convergence, both vertical and horizontal
Strain
Load
Temperature
Tilt
Displacement
Stress

6. Advantages Vibrating wire sensors are well known for
Long term stability
Excellent resolution
Exceptional sensitivity

7. Application in open cut mining
High wall monitoring
Displacement
Tilt
Strain
Load
Water studies

8. Approvals
GEL Instrumentation has approval for use in underground coal mines in Australia
Approval no: IECEx.SIM X
All approved vibrating wire sensors to be used in conjunction with the Model 404 digital readout unit only
Up to 1000 metres of signal cable

9. Pressure transducers Water Gas Other liquids Resolution 0.025% FS
Accuracy 0.1% FS
Pressure ranges from 0.35 to 70 Mpa

10. Strain Gauges Can be used to measure loads in: Rock bolts
Steel tendons
Struts
Chains
Goaf seals

11. Load Cells Can be used to monitor loads on: Conveyor supports
Rock bolts
Cable tendons
Megabolts
Cable bolts etc.

12. Tilt Meters Can be used to monitor deflection in: Struts Supports
Goaf seals
Rib dilution
Roof dilution

13. Temperature
Each of the vibrating wire sensor has a inbuilt thermistor to measure temperature at its installed location

14. Stress Meters Uniaxial type Range in tension 3 MPa
Range in compression 70 MPa

15. The Model 404 Readout

16. Field Data Plots
Borehole Monitoring

17. Field Data Plots
Stress Change in Roof Rock Tunnel

18. Thank you!