If I recall correctly, my three year old mind registered the work of the Seven Dwarves as mining?
This really appeals to the science fiction reader that I was in my youth. I read a book about this. Heinlein, right? "The Moon is a Harsh Mistress?" As I recall the Moon colony (Gingrich was not yet a candidate for mayor) mined various rare earths like lithium or some such thing. They then loaded the rocks into an electrically driven rail gun, a mass driver. The ore fell in the ocean somewehere at a reasonalble depth and were recovered. Easy huh?
Actually it was the marriage customs of the moonies that really interestrd me, but, then, at that age.... pl