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). 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. 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.
A 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. 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.
A 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. The sluice filters out all heavy metals, including mercury, and returns the clean gravel to the river. The average size of a dredge engine is 5 horsepower— about the same size that powers lawnmowers. A suction dredge engine is air cooled and adds nothing to the water.
After sucking up material for a while, place a wide tray, bucket or large gold pan at the end of the sluice. Inspect for pickers or nuggets first, then carefully roll up the riffle matting or miner's moss and wash into the container at the end of the sluice. Rinse any excess gravel that remains in the sluice into container. Process this sluiced material with a gold pan or other fine gold recovery product.
What's the difference between a dredge/highbanker combo and a highbanker or power sluice? For example, #7830 above is called a dredge because an actual dredge nozzle is included and the unit was built for sucking up gravel, etc. from underwater. Notice the shape of the Dredge Header Box on this item -- it is different from the header box on power sluice #7820. A power sluice "washes" material you shovel into it, whereas a dredge sucks material up from a stream through a hose and deposits it into the sluice. #7835 shown above comes with BOTH types of header boxes AND a dredge nozzle and a bigger pump so you can use this one piece of mining equipment as either a sucking dredge or as a power sluice.
Gold recovered using a 2" suction dredge / highbanker combo #6521.
"Here is a pic of some gold we got with the awesome unit you sold me. Regards, Jeff."
