Jeff, 

My husband used to work for a Japanese company that did "trenchless technology," and you might be surprised what those little robotic cameras can do and where they can go.  They are prowling the sewers beneath most of our cities recording our decaying infrastructure.    (The company he worked for had a branch office in Selma back then, so TRC might have talked them into a demonstration run).  

Linda Derry


-----Original Message-----
From: HISTORICAL ARCHAEOLOGY [mailto:[log in to unmask]] On Behalf Of Holland, Jeff
Sent: Tuesday, March 12, 2013 3:54 PM
To: [log in to unmask]
Subject: Re: Liverpool's lost Williamson tunnels unearthed

Our investigations in the tunnels were very limited because of safety. We had a structural engineer on site to evaluate the stability of the one tunnel that we entered. There was no excavation and only a few modern artifacts recovered. 

The city was a bit disappointed that we didn't use cameras mounted on robots or some other high tech approach, but the budget did not allow it. Certainly remote sensing is a legitimate approach, especially for mapping the extent of a network of tunnels, although any number of obstacles could prevent access of a robotic vehicle.