It was a little surprising to read that it was a city well that brought Bertha to a grinding halt. It’s not like there’s no physical evidence of a well on the surface. Like big water pipes, electric poles, fencing, signs, that kind of stuff. Did the contractor not have someone walking the drill path? What happens now? Is Bertha to be buried in cement and call it a day?
The wellhead can be buried yards below the today's surface; or it can be in one of millions of manholes; or it can be in a basement of a new building; or it can be on inaccessible territory; or it can be misidentified; or it can be marked as completely or partially removed, when in fact the casing is still in the ground. Tunnelling under cities is hard exactly for that reason - too many old, abandoned obstacles or essential but poorly marked communications.
Re: “Did the contractor not have someone walking the drill path?”
The cutting wheel makes the path, and it’s too huge back up.
Only one gear - forward.
There is no extra space in front, on top, on bottom, or on the sides.
Bertha has never run up to spec.
Just cutting the first 1000 feet took many months longer than planned.
In theory, Bertha should have been able to grind that pipe into pieces.
As I recall, it’s only a 6 inch pipe.