An Underwater Dredge

Underwater dredges are not as popular as the surface dredges because they are not able to obtain as much fine gold as the surface dredges. Underwater dredges have for the most part been designed because they are portable and compact however the way they can be used is somewhat limited because they are a little bit burdensome to use under water. A submersible dredge needs to be held completely level when it is being used and is not able to get around the corners and some areas that are hard to get to.

Underwater dredges are also not that convenient to use in shallow waters, because they need to get total submerged in order for them to work adequately.

An underwater dredging tube looks somewhat like a flared plastic or metal tube that has a forty five to sixty degree angle bend at the end of it where the water is introduced at a high pressure and it creates a vacuum at the end of the bend it has.

 A high pressure water pump is usually located on a float that sits at the surface of the water and is then pumped down to the dredge through a hose with high pressure. At the end of the flared tube a riffle tray is attached and it has a number of gold traps. When the gravel is sucked into the dredge the heaviest particles – such as gold and other things – get trapped inside the riffle tray. The other particles that are lightweight will flow back into the river.

Underwater dredges are mainly used to sample an area and then a surface dredge is used so that the job can get done adequately.