Underground » Ventilation, Gas Drainage and Monitoring
In response to the great interest in the prediction of outburst zones and detection of geological structures, a caliper logging probe has been developed. The probe is based on the reliable and intrinsically safe vibrating wire strain gauge. The probe is a pump down type designed to protrude from the end of a drill stem and readings taken when the rods are withdrawn. Data from the probe is transferred via a cable to the readout unit at the hole collar.
The Mk 1 and Mk 11 version of the caliper probe have been tested at West Cliff and Myuna collieries respectively and a commercial version of the single arm caliper probe is now available. The entire system has been designed with proven electronics and simple mechanical components to maintain reliability and ruggedness. The accuracy of the caliper probe using the current readout unit is 0.8 mm. The probe can be used in both BQ and NQ drilling rods. The largest hole variation that can be measured with the existing design is 170 mm.