- Gold dredge
The gold dredge is a mechanical method of extracting gold from sand and gravel. The gold dredge involves a mechanical method of digging up the gravel or dirt, using either buckets or suction. The material is then sorted and sifted using water through a series of baffles and ultimately discarding everything but the gold. This material that is washed or sorted away is called tailings.
Concept
The basic concepts of retrieving gold has not changed much from the beginnings of the
gold rush . The concept is that the gold in sand or soil will settle to the bottom, as it is heavier, and the dirt, sand and rock will wash away. The original method was to performplacer mining involved gold panning, sluice boxes and rockers. Each of these methods involves washing away everything and allowing the gold to settle to the bottom of the pan, or in the riffles of the sluice. The gold dredge is the same concep but on a much larger scale.History
By the mid to late 1850s the easily accessible gold in California was gone, but there was still a lot of gold to be mined. The challenge of retrieving the gold took a more professional mining industry approach to make it pay: giant machines and giant companies. Massive floating dredges scooped up millions of tons of river gravels, as steam power and electrical power became available in the early 1900s. Many of these large monsters still exist today in state sponsored heritage areas (
Sumpter Valley Gold Dredge ) or tourist attractions.Today
In the late 1990s and through today, dredging has resurfaced as a popular form of gold mining. Advances in technology allow a small dredge to be carried by a single person to a remote location and profitably process gravel banks on streams that previously were unaccessible by the multi-story hundred's of feet long beasts of the 1930s. [http://fairbanks-alaska.com/gold-dredges.htm fairbanks-alaska.com] - Gold Dredge Number 8] Today dredges are versatile and popular consisting of both floating surface dredges that use a vacuum to suck up gravel from the botton and submersible dregdes. [http://www.keeneeng.com/pamphlets/golddredge.html www.keeneeng.com] - Gold Dredges]
References
External links
* [http://www.golddredgehog.com/dredge.shtml www.golddredgehog.com] Dead link|date=May 2008
* [http://explorenorth.com/library/weekly/aa072999.htm explorenorth.com] - Gold Dredges in the North
* [http://www.nps.gov/archive/yuch/Expanded/mining_history/coal_creek/what_is_a_dredge.htm www.nps.gov] Dead link|date=May 2008
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