# Opal Mining Town in Australia #

There is a misunderstanding of what it means to use tunnels on any non
earth-like body. The key for any habitation is that it is a pressure
chamber. No pressure outside and some atmosphere equivalent inside.
Long snake like irregular forms will not work. All pressure chambers or
vacuum chambers need to minimize surface area (spheres, cylinders). A
tunnel will be be one hole big enough to contain a complete
structure/base/pressure chamber. It will be more like living in a sky
scrapper without windows. Might be horizontal instead of vertical but
the result is the same: total isolation from the surrounding material.