By rosebell
The drill-and-blast phase of the Blackwater Combined Sewer Overflow (CSO) Tunnel project in Virginia, US, is slated to be started by Lynchburg Water Resources (LWR), the municipal utility in Lynchburg, Virginia.
As the municipal utility stated, the Blackwater CSO Tunnel Project, also known as LYHBeyond, is the largest capital improvement project in Lynchburg and protects the city’s waterways.
With the aim of storing up to 4.7 million gallons of combined sewage and stormwater, construction of a nearly mile-long, 12ft diameter underground tunnel is the content of this project.
Commencing construction at the main project site located at the bottom of Seventh Street in Downtown Lynchburg, will be up to LWR’s contractor Atkinson Construction.
Using drill-and-blast excavation methods, the Blackwater CSO Tunnel with 70 to 120ft length, is due to be constructed through a solid rock beneath Blackwater Creek.
The process includes drilling multiple holes into the rock, placing blasting material in the drilled holes, detonating the material, and removing the rock and detonation of each blast hole will be preceded by a series of air horn blares to ensure safety.
13 January 2025 is the scheduled date for first test blast, whereas using 25% of the typical blasting material, and is subject to potential delays.
Including the test blast, all future blasts are going to follow a safety protocol with five short air horn blares five minutes before detonation and another series one minute prior and a long air horn blare will signal all clear after each blast, followed by another long blare to signal to crews that the tunnel shaft is safe to enter.
A 38ft wide shaft already constructed at the Seventh Street site will be the location that drilling and blasting will occur and it will be covered to mitigate noise and contain the blasted rock.
The amount of blasting material will increase with subsequent blasts, from one to two blasts per week for the next two months, to two per day starting this spring.
The planned date for continuing the drill-and-blast phase of the tunnel project is July 2026.
