The main purpose of the two visits was to characterise subsurface conditions on four boreholes, using a suite of seven probes that included High Resolution Acoustic Televiewer (HRAT)®, High Resolution Optical Televiewer (Hi-OPTV)®, 3-Arm Caliper, Formation Density, Nuclear Magnetic Resonance (NMR), Impeller Flowmeter and Temperature Conductivity.
The two visits culminated in four boreholes being logged with two teams of two engineers logging simultaneously. This approach to work minimized downtime and allowed the boreholes to be logged efficiently.
Access to the site was difficult, down an uneven slope, where a track vehicle had to be deployed to assist in transporting equipment down to the boreholes. The logging was conducted using multiple casing pulls where the casing was withdrawn incrementally to protect weak areas of the borehole, a consequence of the varied and challenging geology around Parson’s Tunnel. The logging was completed on each borehole within the project timeframe, with the data providing key information for assessing the stability of the slopes.
