Not sure if it's relevant, but here is something I dug up (pun intended)

http://midcitymessenger.com/2016/01/05/city-officials-approve-demolition-of-old-tulane-avenue-hotel-and-south-alexander-street-home/

I also saved an archive of it, just in case

http://archive.is/uuLhg

I remember reading there is a construction company right next door to Comet Ping Pong which has as one of their specialties, underground / subterranean construction.