Mining, · Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef or placer deposit.These deposits form a mineralized package that is of economic interest to the miner. Ores recovered by mining ...Farmer in the Sky (full text) by Robert Heinlein, · "Farmer in the Sky" is another one of Heinlein's excellent novels. It is set in the "Heinlein solar system" which means Venus and Mars have life. It is about a family trying to be homesteaders on Ganymede as it orbits Jupiter. The descriptions of the sky from the surface of Ganymede are some of the best parts of this well written and engaging story.