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
(photos coming soon once mining of the tunnel is underway)
Site 1 - Launch Zone (Queen City Ave. Bridge)
Connection operations for the Tunnel Boring Machine (TBM) a.k.a. "Granite Janet" within the launch zone take several weeks working day and night. The TBM comes in several different pieces (called "gantries") that will be connected within the launch site as TBM begins drilling. In total, there are 16 gantries pulled behind the TBM, making the entire length of the machine "train" over 570 feet long. There are several support utilities needed for the TBM to operate, including power cables, air supply piping, ventialtion systems and slurry piping all stored within the grantries. This picture is of one of the gantries and support hose being installed.
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 concrete forms to complete the adit walls and floor at DS-2. An adit is a short tunnel constructed horizontally through the rock, which will connect the completed Drop Shaft to the completed Tunnel. Even though the adit is installed in hard rock, concrete is added to the bottom and walls of the blasted rock opening to make a specific engineered size and length "pipe" for stormwater to pass through from the Drop Shaft 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)
Pre-drilling operation to provide clearance for the installation of steel sheet piles. These piles are needed for support of excavation (SOE) installation to hold the soil back within Drop Shaft 4 excavation.
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 will be connected to the drill rig. The drill rig pushes the cans into the ground to create an opening for the vent shaft piping. Once the drilling is complete, soils are removed and a pipe is installed to make a permanent 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)
Installation of a tunnel vent shaft located across from the Drop Shaft 6 location on Massabesic Street near Eliot Hospital. This picture shows the permanent vent piping being installed within an excavated "drill hole" that is roughly 4-5 foot diameter and 50-60 feet deep. These vents will connect directly to the tunnel once it is complete, so that air can escape. On the surface, the vent shaft will stick up out of the ground and be protected for purposes of safety.
Site 8 - Drop Shaft (DS) - 7 (Mammoth Road)
Installation 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.
Site 9 - Consolidation Drainage Piping (Union, S. Willow, Cilley)
Placement of the a specialized "tee" drainage manhole within soil support systems (SOEs). This manhole is part of the new 60-inch drainage pipe being installed near Union, Shasta and Willow Streets. This access manhole is unique because it is made integral with 60-inch diameter pipe for ease of installation. The new 60-inch drainage piping will carry rain water to DS-2.
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)
The tunnel will eventually connect to an outfall structure that will direct rain water to the Merrimack River under the Queen City Ave. 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. Once excavation is complete, the foundation and outfall structure can be installed.
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.
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.