The tunneling process occurs underground using a micro-tunnel boring machine (MTBM); however, shafts are required along the alignment and placed in engineered distances. During tunneling, it may appear not much work is occurring; however, this is being done underground.
The Micro-Tunnel Boring Machine will be operating 24 hours a day at the following locations:
About the Micro-Tunnel Boring Machine
A Micro-Tunnel Boring Machine (MTBM) is machine used to excavate tunnels by breaking the surrounding soil, earth and / or rock to create a large diameter tunnel. First, a large shaft is built which will facilitate lowering of the MTBM into the ground. The MTBM then grinds through soil and other ground conditions. Pipe is then installed behind the micro-tunneling machine to create the tunnel.
The MTBM being used for this project is 4 metres long, 2.3 metres in diameter and weighs approximately 35 tonnes. It's anticipated that the MTBM will tunnel at a speed of about 6 meters per day in the expected conditions.
The MTBM operates under a pressure system to move forward and requires pipe lubrication. This is facilitated by the use of a slurry (water and material mixture) to lubricate the pipes and reduce the friction. When tunneling stops, the slurry may harden and cause the pipes and MTBM not be able to be pushed forward. Because of this, the MTBM will need to operate 24 hours a day, 7 days a week.
Slurry Separation Machine
The Micro-Tunnel Boring Machine (MTBM) tunnels through the ground by breaking up the soil, mixing it with the drilling fluid to form a slurry and then pumping this slurry to the surface.
At the surface, the slurry is pumped into a slurry separation machine which separates the tunneled soil from the drilling fluid.
The tunneled soil is then loaded into dump trucks and hauled away and the drilling fluid is pumped back to the MTBM to be reused.
The slurry separation machine will be utilized at Worksite #1A - Westbound on 29A Avenue and east of 111 Street and Worksite #2 - East of 111 Street and south of 34 Avenue.