This week, the HDD in Sydney had to overcome the breaking of the locating wireline.
The wireline is used to transmit information through a cable, fitted within the drill string. The transmitter, located behind the bore head registers angle, rotation, direction and temperature data. At the surface, the signals from the transmitter are decoded and steering directions are relayed to the bore machine operator.
The wireline was withdrawn and repaired. The drill string was put back down the hole to allow drilling operations to continue.
The delay has caused only a slight setback of a few days at the HDD site.