> On Friday, at the site of one mine near Longnan, a diesel generator was humming and liquids were gurgling through plastic pipes, indicating that at least some mining operations had probably resumed. Heavy rare earths are mined by dumping strong chemicals into holes dug in the top of a hillside. The chemicals dissolve the ore and dribble out of the base of the hill, where they can be pumped to nearby pits for initial processing.
Romans used to do similar things when mining silver. Either dam up a lot of water and flood away an entire hillside or do this and direct channels into the surface and collect all the runoff for processing.
Fascinating!