The boreholes connected the 27m deep Metro station box Level B2 to an existing Ghost Tunnel, which was built last century as part of the Eastern Suburbs Railway line for Bondi and the Illawarra but never completed. Platforms 26 and 27 have sat unused since, but they will now house 17 new communications and power rooms to support the new Sydney Metro at Central Station.

 

The 90m long boreholes were constructed using a Akkerman Guided Boring MAchine, which used a Target Guidance System to accurately drill the Pilot hole to line and grade in Class II Hawkesbury Sandstone. The Pilot Hole was then enlarged to 710mm, before the HDPE conduits were welded and installed into the boreholes. Directhitt then installed the DN 250 PVC Electrical ducts into the HDPE liners and grouted the annuals before final testing and commissioning.