This, of interest because all of our gold rushes happened a century or more in the past. Yet not all the gold has been found, clearly.
The Serra Pelada, for example, prompted a gold rush in Brazil with upwards of 100, 000 artisanal miners, with a black market production estimate of 360 tonnes and nuggets weighing up to 15 pounds.
Link: https://en.wikipedia.org/wiki/Serra_Pelada
So far my summer has had a dearth of adventure, but I may find yet a way to remedy this...