Editing Placer mining (section)

==History==
[[File:De re metallica p 282.jpg|thumb|Plate depicting placer mining from the 1556 book ''[[De re metallica]]'']]
Placers supplied most of the gold for a large part of the ancient world. Hydraulic mining methods such as [[hushing]] were used widely by the Romans across their empire, but especially in the gold fields of northern [[Spain]] after its conquest by [[Augustus]] in 25 BC. One of the largest sites was at [[Las Médulas]], where seven 30 mile long [[Aqueduct (water supply)|aqueduct]]s were used to work the [[alluvial]] gold deposits through the first century AD.  {{Efn|Inclusions of [[platinum-group]] metals in a very large proportion of gold items indicate that the gold was largely derived from placer or alluvial deposits. Platinum group metals are seldom found with gold in hardrock reef or vein deposits.}}

In [[North America]], placer mining was famous in the context of several [[gold rush]]es, particularly the [[California Gold Rush]] and the [[Colorado Gold Rush]], the [[Fraser Canyon Gold Rush]] and the [[Klondike Gold Rush]].

Placer mining continues in many areas of the world as a source of diamonds, industrial minerals and metals, gems (in [[Myanmar]] and [[Sri Lanka]]), platinum, and of gold (in [[Yukon]], [[Alaska]] and [[British Columbia]]).