|
Jagersfontein Mine is an abandoned open-pit mine in South Africa located close to the town of Jagersfontein and about south-west of Bloemfontein.〔("Jagersfontein Mine, Jagersfontein, Free State Province, South Africa" ), Mindat.org〕〔(Jagersfontein ), Places.co.za〕 Since it was first established in 1870,〔(Jagersfontein entry ), ''Encyclopædia Britannica''〕〔("Jagersfontein Mine" ), Showcaves.com〕 two of the ten biggest diamonds ever discovered, the Excelsior and the Reitz (now called the Jubilee), were mined from Jagersfontein.〔 The term "Jagers" has since been coined to denote the distinctive faint bluish tint of the gems from this mine.〔("The Excelsior Diamond" ), Famous, Historic and Notable Diamonds, Tripod.com〕 Among geologists, Jagersfontein is known as a kimberlite pipe,〔(Photograph showing the circular geometry of the Jagersfontein kimberlite ), Department of Terrestrial Magnetism, Carnegie Institution of Washington (Stressed Pyroxenite Nodules from the Jagersfontein Kimberlite ), G. D. Borley and P. Suddaby, Mineralogical Magazine; March 1975 v. 40; no. 309; p. 6-12; (Iron carbide and metallic inclusions in diamonds from Jagersfontein ), A. P. Jones, D. Dobson, I. Wood, A. D. Beard, A. Verchovsky, H. J. Milledge, 9th International Kimberlite Conference Extended Abstract No. 9IKC-A-00360, 2008〕 and a prime locality for mantle xenoliths, some of which are believed to have come from depths of .〔 About 9.6 million carats (1,900 kg) of jewel-quality diamonds were extracted during the mine's century of operation, interrupted only by the two World Wars and the Great Depression.〔 After thirty-nine years of open-pit mining, underground mining began in 1909, and continued until its eventual closure on May 28, 1971, less than a year after the centenary of the first diamond discovery in the area.〔〔 Since then, an Open Mine Museum and the Jagers Mining Village have opened as tourist attractions at the site. Research by historian Steve Lunderstedt in 2005 confirmed that the mine was the biggest hand-excavated hole in the world at , slightly larger than the Big Hole of in Kimberley, which had claimed the title up to then. It is probably not the deepest, though, since the final depth of the Big Hole reached or more. Jagersfontein was dug by hand to a depth of by 1911.〔("Big Hole loses claim to fame" ), Hannatjie van der Merwe, News24.com, May 20, 2005〕 Currently, the mine area is closed to the public.〔(Open Africa - Open Mine Jagersfonteign )〕〔(Community takes on Mining Giants ) - The Weekly, 8 August 2013〕 ==External link== *For Google Maps (Aerial view of Jagersfontein Mine, click here. ) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Jagersfontein Mine」の詳細全文を読む スポンサード リンク
|