Coober Pedy is one strange town. As you approach you are travelling through arid, treeless country. (Oddly, it had rained recently, so it was quite green.) Then suddenly when you are about 10 KM out of town you run into all these piles of white mine tailings. Within the town itself, the piles join up into almost continuous tailings. Miners often start on a hill side and then turn their initial excavations into a home and keep adding tunnels.
I mostly found ochre, but we all bagged some interesting silca crystals.