On 24 September 2025 - after 29 months of boring - the TBM Mary completed the second bored tunnel at the 'HRBT (Hampton Roads Bridge-Tunnel) in Virginia, installing 1,193 rings. click here for the video. The Katherine Slurry Treatment Plant processed approximately 600 tons of soil per ring before transferring the spoils to barges for disposal. 

In June 2025 TBM Mary reached its record of 66 rings installed in one week. The Katherine Slurry Treatment Plant was able to make quick work of the coarse-grained sandy soils found deep beneath the bay bottom. 

As the TBM Mary approached its re-emergence onto the South Island, it passed through the upper layers of the bay made up of fine-grained soils, such as clay, which posed a significant challenge for Katherine in separating the small particles from the slurry. 

Also on South Island, the Hampton Roads Connector Partners crews built the TBM cradle inside the reception shaft, where - after the breakthrough - the cutterhead and shield will be housed. 

Work will now continue with the construction of the roadway, as well as the installation of fire protection and ventilation systems. Meanwhile, crews are working to complete to complete tie-ins to the mega-trestle connecting the tunnels to the Norfolk shoreline.

For further information on the project click here and us/125 for the tunnelbuilder archive and visit www.hrbtexpansion.org. 39/25.