The age and location of SPS 008 in Reynolds St, Balmain, had been causing Sydney Water increasing problems with sewage overflows and the consequent community concerns. The old SPS was eliminated by the construction of SP 1146 approx 250m away in a more secluded area. The gravity flow connection between the new and the old SPS required a Ø530 x 150m long microtunnel in sandstone for the 300 PVC carrier pipe.

Balmain Microtunnelling Pezzimenti Method Freebore in Self Supporting Ground

Balmain Microtunnelling Pezzimenti Length Ground Diameter PVC Pipe

Contract Award

MMA Civil was awarded the contract by Sydney Water to construct the new SPS, gravity mains, rising main and to decommission the old SPS. Pezzimenti Tunnelbore was awarded the microtunnelling works by MMA.


The launch shaft was located in the excavation of the proposed wet well of the new SPS. The depth of the shaft was 11m. The site set up required a steep lead-in ramp to a lower level.

Significant Cost Savings

The 150m microtunnel through sandstone was completed in 6 days. The self-supporting nature of the ground conditions allowed the Pezzimenti LaserboreTM Microtunneling System to employ the Freebore mode, meaning that no encasing pipe (steel or concrete) was required.

This resulted in significant cost savings for the project. Pipes were sliplined into the microtunnel and the annulus grouted.

Balmain Pezzimenti Microtunnelling 150m Routine Freebore


Download Pezzimenti Tunnelbore Microtunnelling Project Balmain 150m Freebore