Inheriting some land in Appalachian Mountains in TN, nice and secluded about 500ft drive up a steep mountain to get to wear the property plateau’s out, at the mid back end of property, Grandfather closed of and buried entrance to abandoned mine shaft, he said the mine shaft is about 50 to 60 feet to the bottom and there are tunnels and cave systems connecting for miles, want to dig it out and start my dream of a underground bunker and escape from people, have extensive knowledge on concrete mixtures and laying, but am a precision machinist by trade. So would like some basic knowledge on fortifying tunnels and access points for stability, plan on hiring a mining expert help navigate some of the dangers of reopening and exploring. Any extra tips and knowledge of doing underground dwellings is much appreciated.