I'm very curious to see what they run into once excavation starts. The old Garrison Creek ran right under this site and I believe the sewer is now just to the west. Some more recent projects have hit really shallow groundwater and crews have found some interesting items that were dumped in when they filled in the valley.
A really awesome rabbithole if you're interested in some Toronto history too, there are whole bridges that were just buried when the creek was filled in. Not sure how many people know about it