Bing Maps - Klondike River
For the sake of shits & giggles, a gravity circuit was the only processing used in the Koldike up until the 1960's. Theses days smaller placer mining ventures still use gravity circuits, meaning no chemical processes, just water and separation.
You can see what was left behind, and no major discovery has been made as to the source of all the placer gold.
The creeks all around Dawson city look like this:
http://binged.it/1KP2QRW
http://www.yukoninfo.com/dawson-city-yukon/dredge-mining/
Gives one to think of Fitzcarraldo, the movie.
-F6