Work on the Potomac River Tunnel in Washington, D.C. has reached another milestone. On 30 October 2026, Itinera Group reported that the joint venture of its U.S. subsidiary Halmar International and CBNA has finished lowering the project’s second tunnel boring machine, named Emily, into the launch shaft at West Potomac Park.
Two machines, two very different ground conditions
According to the report, the launch shaft sits approximately 100 feet below ground. Emily has been built for the softer ground found along the southern section of the route and is now being assembled and tested before it starts excavating.
The first machine, Mary, has been at work since last April on the northern section, cutting through hard bedrock towards Georgetown University. In the coming months the two TBMs are expected to bore at the same time, heading in opposite directions along an alignment of approximately 8.9 km.
The tunnel is part of DC Water’s Clean Rivers Program, which is designed to capture excess flows from the sewer system and carry them away, helping to protect the ecosystem of the Potomac River.
What it means for drilling operations
Running two machines in opposite directions through contrasting geology is a good reminder that one project can place very different demands on equipment. Hard bedrock drives tend to put steady pressure on cutting tools, bearings and hydraulic systems, while softer ground brings its own challenges around muck handling and face support.
For contractors, the key to keeping both drives on schedule is planning: realistic wear expectations for each ground type, spare parts staged close to the shaft, and maintenance windows that do not hold up the critical path. The same thinking applies to the drill rigs and support equipment working around shafts and portals, where a single failed component can stop the whole work face.
At Razor Spare, we supply high-quality alternative spare parts for rock drilling equipment, helping contractors and mines keep their machines working and their downtime short.
Source: Itinera Group – “Potomac River Tunnel project, Washington D.C.: second TBM ‘Emily’ lowered into launch shaft”, 30 October 2026.
https://www.itinera-spa.it/en/potomac-river-tunnel-project-washington-d-c-second-tbm-emily-lowered-into-launch-shaft/
This article is an original summary prepared by Razor Spare based on the source above.