A bit about W Australia mines

When Herbert Hoover was a young man he was a brilliant mining engineer. He lived in this house....

overlooking this hole in the ground....

About a kilometre across and 300 metres deep.
BTW: The house was a very nice B&B

This is the Sons of Gwalia mine near Leonora WA but the most interesting thing is that it is no longer an open cut mine. At a certain level below the surface they have drilled into the rock face and are now spiralling down and along for kilometres underground.

Here's an entrance of another mine....

....in a similar situation. The truck is bigger than my house. At the big-pit in Kalgoorlie each load is 225 tonnes and carries $10,000 in refined gold after processing and from the viewing gallery one can see at least six of them climbing out of the hole all day long.