I would live here if not for my Vitamine D defficiency

Yep. In the middle of bloody woop woop

The walls look like cream painted egg crates kept upside down

As an aussie who has been here, i have to say that although the entire town is known for finding opals and the purpose of those mines was to mine them, I have honestly never heard of anyone finding opals when renovating. But if they did it was probably some thin white opal still in the walls that wasn't worth digging. Either way its a cool place. Literally lol.

I've lived there. It's great but the only problem is there are randomly placed massive holes in the ground where the opal mines are. If you don't look where you're going you'll probably fall in.

The entire place is a dust pile with holes EVERYWHERE. And not everyone lives underground, especially not in abandoned mines - they're specially dug houses, usually into the side of hills. Just because it gets so hot there you need the earth to insulate you.

The vitamin D-eficiency.

Sounds like Dwarf Fortress

This place is called Coober Pedy - the name comes from the Aboriginal "kupa pitti", which means "white man in a hole".