Hydraulic mining is a form of mining that uses high-pressure jets of
water to dislodge rock material or move sediment. In the placer mining
of gold or tin, the resulting water-sediment slurry is directed
through sluice boxes to remove the gold. It is also used in mining
kaolin and coal.Hydraulic mining developed from ancient Roman
techniques that used water to excavate soft underground deposits. Its
modern form, using pressurized water jets produced by a nozzle called
a "monitor", came about in the 1850s during the California Gold Rush
in the United States. Though successful in extracting gold-rich
minerals, the widespread use of the process resulted in extensive
environmental damage, such as increased flooding and erosion, and
sediment blocking waterways and covering farm fields. These problems
led to its legal regulation. Hydraulic mining has been used in various
forms around the world.Hydraulic mining had its precursor in the
practice of ground sluicing, a development of which is also known as
"hushing", in which surface streams of water were diverted so as to
erode gold-bearing gravels. This was originally used in the Roman
empire in the first centuries BC and AD, and expanded throughout the
empire wherever alluvial deposits occurred. The Romans used ground
sluicing to remove overburden and the gold-bearing debris in Las
Médulas of Spain, and Dolaucothi in Great Britain. The method was
also used in Elizabethan England and Wales (and rarely, Scotland) for
developing lead, tin and copper mines.Water was used on a large scale
by Roman engineers in the first centuries BC and AD when the Roman
empire was expanding rapidly in Europe. Using a process later known as
hushing, the Romans stored a large volume of water in a reservoir
immediately above the area to be mined; the water was then quickly
released. The resulting wave of water removed overburden and exposed
bedrock. Gold veins in the bedrock were then worked using a number of
techniques, and water power was used again to remove debris. The
remains at Las Médulas and in surrounding areas show badland scenery
on a gigantic scale owing to hydraulicking of the rich alluvial gold
deposits. Las Médulas is now a UNESCO World Heritage site. The site
shows the remains of at least seven large aqueducts of up to 30 miles
(48 km) in length feeding large supplies of water into the site. The
gold-mining operations were described in vivid terms by Pliny the
Elder in his Natural History published in the first century AD. Pliny
was a procurator in Hispania Terraconensis in the 70s AD and witnessed
the operations himself. The use of hushing has been confirmed by field
survey and archaeology at Dolaucothi in South Wales, the only known
Roman gold mine in Great Britain. Hydraulic mining Biography, NetWorth, Height, Age, Weight, Family, Married, Son, Daughter