The first permit has been issued for Cassidy on Canal, the 33-story apartment tower from The Habitat Company, and crews are on site ready to drill into the earth. I’m told caissons aren’t quite ready to go into the ground just yet, but you can see rebar cages being prepped, so they’ll be ready when shafts start drilling. That process is expected to begin Monday.

I learned some fascinating things this week about those old freight tunnels running under the city, including this site. Caissons can be drilled through the tunnels, but not until the tunnels themselves are filled. Bulkheads are framed and filled at each end of the tunnel, and then the entire tunnel is filled with grout. (It’s a lot of grout.) Once the grout sets, then the caissons can be drilled & filled.

Anyway, that’s what Stalworth Underground is up to. I guess when you put the word “Underground” in your name, you’re prepared for anything and everything that pops up beneath the surface.

Enjoying the photos? Metra and CTA rides (and Amtrak trains to Milwaukee), Zipcars, Divvy Bikes, camera lenses, domain fees, snacks & energy drinks, and comfortable walking shoes add up. You can help offset expenses by making a greatly-appreciated donation to Building Up Chicago.