Thanks for your report, Jon.  I have heard of that project, it is something I would like to see, as I am invested in a very small way into the ND missle silos.

Back in the 1960's when those were being built, I worked 5 summers for Anaconda American Brass while going to school, and even after teaching the first few years.  I really enjoyed the job, and one of the projects we had was to make the 6" electrical conduit used in those silos.  Most of our flexible plastic-coated conduit was half to one inch, so the 6 inch was a special project, taking lots of time an people to make a good run.  As we made this unusual product, I kept imagining how it might have been used.  It would be nice to visit the project to see if some of our issue was part of it.