Further to the recent update shared with the Schulich community, we have now been informed by the TTC that the vibrations experienced Wednesday morning (26 September) did, in fact, relate to the tunnel boring machine (TBM). The TBM encountered one or more boulders and grinding through the boulders caused the vibrations. We have been advised by the TTC's contractor that this scenario is within normal operating possibilities for this type of activity. Encountering boulders cannot be anticipated and may occur at any time during the tunneling as it is not known if any other boulders are in the path of the TBMs.
Click here for the complete update in PDF.