Cemetery Brook Drain Tunnel Project Photos
Welcome to the photos page of the CBDT project website! Provided below are current photos showing the status of each of the major project locations, including the TBM Launch Zone, the Tunnel and each of the Drop Shafts. Located at the bottom of this webpage is "Beyond the Site" with status photos or images associated with design, planning, major project milestones and various construction aspects of the tunnel project.
Project Site Status Photos
Site 0 - Tunnel
The first drive for The Tunnel Boring Machine (TBM) a.k.a. "Granite Janet" was completed in September, which measured approximately 200 feet. This picture is looking out of the tunnel towards the launch zone showing concrete segments that make up the tunnel. Utility cables, vent piping and rail tracks are used to feed material to and support TBM operations.
Site 1 - Launch Zone (Queen City Ave. Bridge)
"Granite Janet" was assembled and mined for 200 feet in September starting from the Launch Zone towards Queen City Ave. The TBM moves by pushing against concrete segments that are installed near the back of the TBM. This picture shows the outside of the concrete tunnel segments within the launch zone that were used to drive the TBM forward. These few concrete segments will be removed from the launch zone. Gantries and supplies will be fed to the TBM through the launch zone and through these segments during the initial mining process. The launch zone is a very active site and more support pictures of that activity will be provided in the future.
Site 2 - Drop Shaft (DS) - 1 (Queen City Ave.)
As controlled blasting and support systems within Drop Shaft 1 are completed to reach the full vertical depth of 50 feet below ground, the blasting operations are shifted to complete a large horizontal hole that will connect the Drop Shaft to the future tunnel. This large hole is somewhat like a cave and is called an "adit". The adit is blasted through the hard rock by drilling many small holes and placing explosive material that will break up the rock so it can be removed and brought to the surface.
Site 3 - Drop Shaft (DS) - 2 (Union Street)
Placement of the permanent pipe bend, which is used to connect the vertical shaft to the horizontal adit walls and floor at DS-2. Once concrete for the adit bottom and walls is complete, the pipe bend is installed. This will allow stormwater to pass smoothly through from the Drop Shaft, into the adit and eventually to the Tunnel.
Site 4 - Drop Shaft (DS) - 3 (Beech Street)
Drilling of ports and installation of grout material at the Drop Shaft 3 ground improvement area using "jet grouting" technology. Ground improvements are needed at several locations along the tunnel path. The grout material is injected into the ground 60-80 feet below the surface using hundreds of small drilled holes. High pressures are used to inject the grout into soft soils to "harden" the soft ground. Eventually, the TBM will drill through this hardened ground and the improved soil will be used to control groundwater and provide safe locations for the TBM to be maintained.
Site 5 - Drop Shaft (DS) - 4 (Wilson Street)
The installation of steel sheet piles which are used for support of excavation (SOE) installation to hold the soil back within Drop Shaft 4 excavation. Once sheet piles are driven down to the top of bedrock depths, the soil can be safely removed and support bracing installed to stabilize the sheet piles. Bedrock depths can vary greatly, resulting in sheet piles that stick up above the ground at different heights. To make work easier and safer, the top of sheets are cut off to the same height.
Site 6 - Drop Shaft (DS) - 5 (Taylor Street)
Installation of several tunnel vent shafts located at Drop Shaft 5 location near Taylor Street. Vents are drilled using a large diameter drill bit that comes in different sections (sometimes called "cans"). These large steel cans are in the forefront of this picture and connected to the drill rig. The drill rig pushes the cans into the ground to create an opening for the vent shaft piping. The auger on the end of the drill rig drills out dirt or rock and removes the material from the "can". Once complete, a permanent vertical pipe will be installed in the "can" to create the vent. These vents are used throughout the length of the tunnel to remove air as the tunnel fills with water during rain events.
Site 7 - Drop Shaft (DS) - 6 (Massabesic Street)
Test pits to locate and verify underground utilities around Drop Shaft 6. A large vacuum truck is used to carefully dig around underground infrastructure so it can be mapped before installation of the drop shaft can occur. Once the infrastructure is mapped, the support of excavation (SOE) will be designed to avoid interruption of utilities. Like at other drop shaft locations, the SOE provides a safe excavation to drill and blast and install permanent drop shaft components.
Site 8 - Drop Shaft (DS) - 7 (Mammoth Road)
Pressure testing of a water hydrant located in Mammoth Road for water supply at future location of Drop Shaft 7. The construction at each of the Drop Shafts requires a lot of water to complete the work. Each of the Drop Shaft locations for this project required special permission to connect to the water supply. The contractor typically uses a hydrant to supply construction water to the site. This test will confirm there are no leaks with the new hydrant installation.
Site 9 - Consolidation Drainage Piping (Union, S. Willow, Cilley)
Before new 60-inch diameter drain piping can be installed under Cilley Road, the bedrock has to be removed to the correct depth below ground. This is typically completed by controlled blasting. This picture shows the rock being blasted. For safety purposes, large, heavy rubber mats are used to cover the blast area so large rock does not travel outside the work area when its blasted. When completed, the new 60-inch drainage piping will carry stormwater from Cilley Road to the DS-2 location near Union St.
Site 10 - Supplemental Vent Shaft (SV) - 2 (Maple & Silver)
Like Site 4 above, the tunnel vent shaft (or supplemental vent) near Maple and Silver Street also requires ground improvements. This picture is of installation of drill ports and grout material being placed into the ground using "jet grouting" technology. Ground improvements are needed at several locations along the tunnel path.
Site 11 - Tunnel Outfall Structure (Merrimack River)
When completed, the tunnel will connect to an outfall structure that will direct stormwater into the Merrimack River at a location under the Queen City Avenue Bridge. This picture shows the installation of sheet piles on the banks of the river. These steel "sheets" link together to create a temporary wall that hold back soil as the river bank is excavated, a.k.a Support of Excavation (SOE). Once excavation is complete, the foundation and outfall structure can be installed. This structure will be constructed of placed concrete and will contain large blocks that will control stormwater flow velocity before draining into the river.
Previous Site Photo Links
Select the links below to view and download past project photos
September 2025
October 2025
November 2025
December 2025
January 2026
February 2026
March 2026
April 2026
May 2026
June 2026
CBDT Beyond the Site
This section includes major project milestones, TBM details, and miscellaneous photos of important project components that support the mining operation or major construction.
Project Milestone Photos
June 2026 - Delivery of two sections (sheilds) of the Tunnel Boring Machine arrive in Manchester from Germany (via Portsmouth, NH)
June 2026 - The Tunnel Boring Machine Arrives at the Launch Zone
June 2026 - The Tunnel Boring Machine Cutterhead Arrives at the Launch Zone
June 2026 - Placement of the Tunnel Boring Machine Front Shield into the launch zone excavation with members of the project team watching.
June 2026 - Drop Shaft 2 Rock Excavation is completed
June 2026 - The end of Drop Shaft 2 adit is completed. This rock face is the location that the DS-2 adit will connect to the tunnel, once the TBM mines past this location.
August 2026 - Once the TBM is assembled and before it begins mining, it is signed by members of the team. The TBM started mining in September of 2026.
September 2026 - Drop Shaft 1 Rock Excavation is completed.
September 2026 - Inspection of the Drop Shaft 2 Adit construction.
Tunnel Boring Machine (TBM) Photos
Tunnel Boring Machine cutterhead under fabrication in Germany
Tunnel Boring Machine interior with segment mold on conveyor, under fabrication in Germany
Tunnel Boring Machine interior behind the cutterhead, 16 cylinders that help push and drive, under fabrication in Germany
Tunnel Boring Machine interior precast concrete segment conveyor
Project Support Photos
Tunnel Segment Forms - Used to pour precast concrete tunnel liner segments at the remote production plant in Connecticut
Completed precast concrete tunnel segments - These pieces will be delivered from Connecticut to the launch zone site and stored until they are ready to be placed in the tunnel. These segments will be part of the finished tunnel walls.
Tunnel Boring Machine push frame design - Used at the start of the tunnel to push the tunneling machine into the ground
Tunnel Boring Machine push frame - The vertical section of the push frame assembly
Slurry plant installation at the Launch Zone. This plant is used to produce a thick liquid that will be pumped to the front of the Tunnel Boring Machine cutterhead. This slurry will support the excavated face of the tunnel and will also be used to carry the mined material from the tunnel back to the production plant.