Michels Canada is honoured to be part of the McLoughlin Point Wastewater Treatment Plant outfall project named the 2019 Canadian Project of the Year at No-Dig North in Calgary, AB.
We completed a tunnel through hard granite from a shaft near the shore of Esquimalt, BC into the Pacific Ocean. The 2,121-mm diameter tunnel will be an outfall for an under-construction wastewater treatment plant that will serve the Victoria Harbour communities on Vancouver Island.
The 117-metre tunnel was completed in a single drive from a 15-metre deep rock wall shaft out into a rock mattress retrieval pad. The ocean depth at the tunnel exit was 11 metres. A Herrenknecht AVN 1800 microtunnel boring machine (MTBM) was used to complete the drive. MTBMs are typically operated remotely from an above-ground control container; however, for this project – given the size of the shaft – much of the ancillary equipment, including the control container, was located in the upper and lower tiers of the shaft. Ancillary work to the tunneling included joint welding, contact grouting, steel casing coating and blind flange installation. All work was performed in confined space on a severely congested construction site.
Tunneling started in early February and was completed in May. Once the MTBM arrived in the rock trench under the sea, it was brought to the surface using a technique known as a wet retrieval. The 96,000-pound MTBM was loaded onto a barge and transported to Vancouver, where it is being used on another project.
Michels Canada is one of the most experienced contractors at successfully executing wet retrievals of an MTBM.
