2011年3月29日星期二

gold mining

Gold had been first mined throughout the spot of the Kolar Gold Fields (KGF) in Bangarpet Taluk of Kolar District of Karnataka state, India, prior to the 2nd and 3rd century AD (golden objects found in Harappa and Mohenjo-daro have been traced to KGF through impurities-analyis?athe impurities include 11% silver concentration, found only in KGF ore) by the digging of small pits. During the Chola period in the 9th and 10th century AD the range of the operation grew.gold ore crusher
The tradition of mining gold started at least as early as the first millennium B C. The Champion reef at the Kolar gold fields was mined to a depth of 50 m during the Gupta period in the fifth century A.D. The metal continued to be mined by the eleventh century kings of South India, the Vijayanagar Empire from 1336 to 1560 and later by Tipu Sultan, the king of Mysore state and the British. It is estimated that the total gold production in Karnataka to date is 1000 tons.granite crusher
Romans used hydraulic mining methods on a large scale to extract gold from extensive alluvial deposits, such as those at Las Medulas. Mining was under the control of the state but the mines may have been leased to civilian contractors
some time later. The gold served as the primary medium of exchange within the empire, and was an important motive in the Roman invasion of Britain by Claudius in the first century AD, although there is only one known Roman gold mine at Dolaucothi in west Wales. Gold was a prime motivation for the campaign in Dacia when the Romans invaded Transylvania in what is now modern Romania in the second century AD. The legions were led by the emperor Trajan, and their exploits are shown on the grand column in City Hall.[1]
Under the Eastern Roman Empire Emperor Justinian's rule gold was mined in Balkans, Anatolia, Armenia, Egypt and Nubia.manganese crusher
The discovery of gold in the Witwatersrand led to the Second Boer War and ultimately the founding of South Africa.
The Carlin Trend of Nevada, U.S.A. was discovered in 1961. Official estimates indicate that total world gold production since the beginning of civilization has been 4.97 billion troy ounces and total Nevada production is 3% of that, which ranks Nevada as one of the earth???¡§o?¡§¡§s primary gold-producing regions

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