If you're wondering how a gold dredge can literally suck up gravel from the bottom of a stream without the gravel going through the pump and destroying it, it is because of a handy device called a suction nozzle or power jet nozzle. These devices convert the pressurized water discharged from the pump into a vacuum.
Generally speaking, a dredge that is designed to work with the sluice on a stand, in shallow water, is almost always equipped with a suction nozzle. A dredge designed to work on flotation, with a compressor for underwater dredging, is almost always equipped as a power jet. Since a power jet and supply hose must be kept under water at all times, it won't work very well in shallow water. Shown below is a wide variety of gold dredge nozzles from several reputable manufacturers. Learn more about how a gold dredge works.
