A novel borehole surveying system for underground mining: Design and performance assessment

Abstract

At present there is a lack of an instrument to measure the trajectory of up-holes in a safe and efficient way with minor disruption of underground production. To overcome this, a mechanically operated probe equipped with Inertial Measurement Units (IMU) and centralisers is integrated in an explosive charge-up unit, which allows the operator to start and stop the measurements from a safe area, while he views the records in real time in a handheld PC. The system incorporates a real-time quality indicator based in the 95% confidence standard deviational ellipse (SDE) of the toe’s positions that clearly indicates whether the survey should be repeated before moving to the next blasthole to ensure measurements with limited uncertainty. In-field data shows an accuracy and repeatability between measurements below 1.3 cm/m, which ensures detecting drilling errors in production rings, often of amount to several tens of centimetres, that may compromise blast results.