The average size of a dredge engine is 5 horsepower- about the same size that powers lawnmowers. The sluice filters out all heavy metals, including mercury, and returns the clean gravel to the river. The size of a gold dredge (1.5 inch, 2 inch, etc.) is determined by the diameter of the suction hose- the larger diameter the hose, the more material can be processed.Ī floating gold dredge is essentially a floating sluicebox that uses an engine and pump to create a vacuum and send gravel (hopefully gold-bearing gravel!) into the sluice box suspended between the two pontoons. Plus, advances in technology allow a small surface gold dredge to be carried by a single person to a remote stream or river and profitably process gold-bearing material.Ī suction dredge used along the shoreline works like a large vacuum cleaner by sucking up underwater gold-bearing material like rocks, gravel, sand, and dirt and forcing it through a highbanker or power sluice that is capable of recovering very fine particles of gold. Sandy or gravel river banks contain large deposits of alluvial gold (loose pieces of gold or gold-bearing sand), and dredging is a great way to recover this gold.

Over the last 10 years or so, dredging has resurfaced as a popular form of gold mining (except in California where dredging is currently banned).

Gold hand dredge blue print