At these grades, IN THEORY, you have to do gravity concentration, before cyanidation of the tailings IMO. Not really worth your time to do tailings, when there is so much high grade ore. First you pick up the large nuggets, then the smaller, then the dust, then centrifugate, then cyanide, etc. The issue is the plant and visibility. Many operations have been shut down, equipment stolen, miners missing, etc. Nobody really owns this land. The wild west or Alaska were a cocktail party compared to these criminals/military, etc. Right now is a bad time to get down there as the new governor is exterminating the gangs loyal to the old governor, military, etc, etc, etc.
I repeat: This is a clandestine operation, to be kept small, and private. I move in and out at dawn/dusk, make noise only during storms, etc. Smuggle the gold out using a very safe protocol. You can hear anyone coming since it is perfect solitude. Few can handle this level of freedom. The area is the size of Spain, but only a few thousand people are dispersed throughout the territory. There is gold, diamonds, Uranium, Coltan, etc, etc, etc, In amounts that rival the original deposits of California, Colorado or the Klondike, or wherever. These are the original, oldest rocks on the planet. All valuable minerals are here. Come and get them!.
All international mining corps have lost millions trying to operate here. Chinese, russians, etc, etc. They come and die by malaria, bullet, boredom, or else.
Jimmie Angel (Angel Falls named after he landed on the wrong mountain of gold), spent most of his adventuring life here, before I was born, looking for "the river of gold". Many stories, some true, some myth, but tons of gold on the ground. I'll leave the lesser minerals for others.