In April in the South Island launch shaft, the HRBT project team tested the electrical and hydraulic systems of the completely reconstructed TBM Mary. They performed final system tests before starting the excavation of the first of two new tunnels under the Hampton Roads waterway.

On Monday, April 17, the HRBT Expansion project personnel gathered to christen TBM Mary and STP (slurry treatment plant) Katherine. The ceremony involved breaking a bottle of champagne on each machine as a celebration of good fortune for the equipment and the crew.   

Through planning, preparation, and partnership with Dominion Energy, the system upgrades needed to supply the power to the TBM and STP were completed ahead of schedule. Efforts included installing 9.65 km (6 miles) of new electrical feeder lines from the Taussig substation in Norfolk to the South Trestle, which carries the lines to a new substation on the South Island. This landside upgrade not only provides power for the TBM and STP, but also will remain after tunnel completion to support future growth in the project corridor area.   

This electricity supplies numerous systems on the TBM, such as powering the 54 thrust rams that move the machine forward and enabling the cutterhead’s rotation. That same energy is also needed to power the high-pressure pumps transporting the excavated material to the slurry treatment plant, as well as powering the STP’s de-sanding systems, conveyor belts, and filter presses.  

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