History Gold Dredge operating in Nome, Alaska in 1993īy the mid to late 1850s the easily accessible placer gold in California was gone, but much gold remained. Hence the efficiency of gold dredges differs greatly depending on its specifications. Even though the concept is simple in principle, dredges can be engineered in different ways allowing to catch different sizes of gold specimen. They allow profitable mining at relatively low operational costs. Gold dredges are an important tool of gold miners around the world.

Professional gold miner using an advanced dredge system. The gold dredge is the same concept but on a much larger scale. Gold then settles to the bottom of the pan, or into the bottom of the riffles of the sluice box. Each method involves washing sand, gravel and dirt in water. The original methods to perform placer mining involved gold panning, sluice boxes, and rockers. The concept is that the gold in sand or soil will settle to the bottom because gold is heavy/dense, and dirt, sand and rock will wash away, leaving the gold behind. The basic concept of retrieving gold via placer mining has not changed since antiquity. The rocks deposited behind the dredge (by the stacker) are called 'tailing piles.' The holes in the screen were intended to screen out rocks (e.g., 3/4 inch holes in the screen sent anything larger than 3/4 inch to the stacker). The material that is washed or sorted away is called tailings. The cylinder has many holes in it to allow undersized material (including gold) to fall into a sluice box.

On large gold dredges, the buckets dump the material into a steel rotating cylinder (a specific type of trommel called 'the screen') that is sloped downward toward a rubber belt (the stacker) that carries away oversize material (rocks) and dumps the rocks behind the dredge. The material is then sorted/sifted using water. Small suction machines are currently marketed as 'gold dredges' to individuals seeking gold: just offshore from the beach of Nome, Alaska, for instance.Ī large gold dredge uses a mechanical method to excavate material (sand, gravel, dirt, etc.) using steel 'buckets' on a circular, continuous 'bucketline' at the front end of the dredge. The original gold dredges were large, multi-story machines built in the first half of the 1900s.

Gold Dredge, Klondike River, Canada, 1915 The Yankee Fork dredge near Bonanza City, Idaho, which operated into the 1950s.Ī gold dredge is a placer mining machine that extracts gold from sand, gravel, and dirt using water and mechanical methods. For the historic landmark in the United States, see Gold Dredge.

Gold dredge pump portable floating