More Tunnels Exposed

The good folks on the Urban Exploration Resource forum note that excavations for the forthcoming Atrium building at the corner of Yates and Blanshard appear to have unveiled a pair of tunnels, shown in the photo at right. What are they exactly? Page 17 of Victoria: Secrets of The City, the predecessor to my book, may provide the answer:

Telus's main exchange at 826 Yates Street has an L-shaped tunnel two stories below the building that runs from Yates to Johnson and then down another 300 feet to the intersection of Blanshard and Johnson. The vault is a repository for hundreds of phone lines.