A sewage processor in resource-poor Japan has discovered ... well, it's not a gold mine, it's better. Ash left over from sewage incineration at the Suwa sewage processing facility northwest of Toyko yields 1890 grams of gold per ton, dwarfing the 20-40 grams per ton that Sumitomo Metal Mining Co. Ltd. recovers from its highly-productive Hiskikari gold mine.
I met a physician once who said there was a lot of money in diarrhea, if you had the patience (patients?) for the work. It seems he was right.