posted on Apr, 3 2009 @ 08:54 PM
from my mine rescue experience it varies in deference parts of the country.
Railroad tunnels and Dry caves are the best.
Dry mines are next best.
Wet caves/ mines are questionable due to rain flooding them and the cold temperatures is them. This will limit the time you can stay in them.
plus the water causes any organic to rot and this may cause high levels of H2S, methane CO2 and CO and low levels of O2
With any mine or cave you need air circulation,
this means that there is more then one entrance.
Any mine/cave with large numbers of bats can be a problem with the danger of rabies and gases from them living in the mine/cave.
A few bats are in most cases no problem. this just shows the the air is breathable.
I would not explore mines without proper training and safety equipment.
I have explored over 5000 mines and have the training. But there are mines that look safe that I would not go into because of the dangers in those
mines without a full mine rescue team.