Probably most prevalent gold recovery technique is for fine gold. There is a lot of fine gold available there in rivers, beaches, streams, and even deserts. Recovery has always been a problem.
There are lots of techniques the famous techniques are:
Most ordinary sluice boxes hardly touch the stuff. You drop additional fine gold out of your sluice box than you recover.
There are 4 things that happened that makes you lose gold
First: Some flour gold or fine actually lifts on the water’s surface making gravity separation impossible.
Second: A lot of fine gold is basically carried along with the dumped back and current into the river or stream.
Third: Flow rate or incorrect angle through your sluice automatically expels this fine stuff.
Fourth: Sectors of sluice boxes are poorly equipped to accurately catch the fine material in the fine gold recovery.
There is a simple trick that is discovered to catch fine gold it is called High Production Sluice Box
This trick is to extended a tuned the nonstop capture system to just catch fine gold.
The High Gold Sluice Box will trap gold up to 1/8 ounce, of course gold flakes and gold particles.
Another technique is the Hydraulic engineering:
2-The Hydraulic elevators
The Hydraulic elevators were used to reach leads of sedimentary gold that were covered with gravel.
Most elevators worked like pulling slurry of gravel, massive vacuum cleaners, and water up from underneath huge gravel terraces.
Engineering was used to interpretation river beds. The 2 most well-known examples are the barrier gates squarely of the Kawarau River draining Lake Wakatipu at Frankton and The Oxenbridge tunnel on the Shotover River.
Some gold was found in the visible bed of the Shotover once the water was abstracted through the tunnel.
3- Hard rock mining
Hard-rock mines shadowed quartz veins, which contained gold. Underground mining was very expensive as the roofs supported and the tunnels had to be blasted. Mines such as those at Waiuta on the West Coast and Coromandel Peninsula followed ridges until they became low grade or too deep to be mined economically.