Using Water -

Present-
The principles of using water for recovering gold are amplified with the use of a Suction Dredge. Considering that at best, an expert panner might be able to process 1 cubic yard of gravel in a day and a 4" dredge can move up to 12 yards per hour it is easy to see why dredging is a popular prospecting method.

The Suction Dredge can be described as an underwater vacuum cleaner. It has a motor that drives a pump. The intake of the pump pulls water from the river and sends it out through a high pressure hose that joins the Jet Tube. The interface of the pressure tube into the jet tube creates a Venturi effect that causes the suction pressure through the Suction Hose. A 4" Dredge has enough suction force to easily suck a man's hand right into the nozzle! It can pick up a 10 pound rock and hold it firmly against the nozzle. Keep hand and fingers away from the nozzle! The material that is picked up at the nozzle end travels to the Sluice Box where the riffles catch the heavy values.