History
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 aqueducts were used to work the alluvial gold deposits through the first century AD. (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 rushes, particularly the California 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 the Yukon, Alaska and British Columbia).
Read more about this topic: Placer Mining
Famous quotes containing the word history:
“Classes struggle, some classes triumph, others are eliminated. Such is history; such is the history of civilization for thousands of years.”
—Mao Zedong (1893–1976)
“The principle office of history I take to be this: to prevent virtuous actions from being forgotten, and that evil words and deeds should fear an infamous reputation with posterity.”
—Tacitus (c. 55–117)
“The principle that human nature, in its psychological aspects, is nothing more than a product of history and given social relations removes all barriers to coercion and manipulation by the powerful.”
—Noam Chomsky (b. 1928)