Big Becky breaks into the light

Final breakthrough for the 14.4m diameter hard rock TBM used to bore the Niagara Tunnel happened on Friday.

While the Robbins main beam machine has completed tunnelling, contractor Strabag still has two years of work left to complete on the 10.2km tunnel. The 12.8m finished diameter tunnel will be fully lined with both 600mm thick continuously poured concrete and a polyolefin waterproof membrane to prevent leakage.

Right before Big Becky bore through the remaining rock and shotcrete of the tunnel to arrive in a 100m deep shaft, Ontario Power Generation announced the TBM’s cutterhead would be put on display in the city of Niagara as part of the project’s legacy.