This is a pretty good video on the same thing. This is the "Undecided with Matt Ferrell" channel on youtube. https://www.youtube.com/watch?v=g8sjdOjNxIE

There are the usual adds, but nothing unusual in that respect. Seems like a pretty good summary.

Pretty cool startup. Digging 20km deep holes, and only in 3-4 months, this would be amazing.