User blog comment:Darkcloud1111/Good Idea, Bad Idea~Mountain Glenn/@comment-24435688-20141013065426/@comment-17099359-20141013234725

Well we don't actually know what cause the explosion. Could have been a accident.

Remember this was Vale's first expansion.Yes they didn't want to die but I doubt they wanted to abandon a project they probably worked extremely hard to push forward or start it all over again.So they took the option that would keep them alive and the project alive and went underground.

Sure going back to Vale would be the most logical option. But people dont always go for the most logical option. (Which is probably part of the reason why mountain Glenn failed in the first place)