I can only GUESS that the real story is the tunnels were being used by kids to do drugs,or for similar purposes,and the local pols didn't want to admit they have a drug/crime problem.
So they contacted the army to blow the tunnels shut,and since this was a really rare opportunity to gain this type of experience,the local Army engineer detachment jumped all over it.
I am certain it had nothing to do with ghosts,though.