Mponeng Mine This photograph comes from the world’s deepest active mine, Mponeng Gold mine in
Mponeng MineThis photograph comes from the world’s deepest active mine, Mponeng Gold mine in South Africa.The mine currently reaches a depth of nearly 4 kilometers beneath the Earth’s surface. The deeper into the planet any mine goes, the warmer it gets, and this mine currently reaches temperatures of 60 degrees Celsius (140 degrees fahrenheit). Fans and other cooling systems are used to keep the heat down, but as you see it’s still a rough environment.This mine is one of several targeting some of the world’s richest deposits of gold. South Africa is home to a series of ancient rocks that date back to the Archean, over 2.5 billion years old. At the time, some portions of the area that eventually became South Africa were above water and some were below. The areas that were above ground were almost certainly host to a variety of volcanic types, including komatiite volcanoes – volcanoes that erupted incredibly hot lavas, hotter than anything on Earth today.Because these lavas formed at such high temperatures, they were able to pick up elements from the mantle that otherwise might have stayed put, including gold. When they reached the surface, the gold formed solid grains inter-mixed with other components like pyrite. These eruptions 3 billion or so years ago were the original source of the gold.Interestingly though, the gold is no longer found in those volcanoes. The gold nuggets have been rounded and transported; they were moved by water downslope into a sedimentary basin known as the Witwatersrand basin. The gold accumulated in sedimentary rocks that were later buried and metamorphosed over geologic time.Today, mines like this one are some of the richest sources of gold on the planet. This mine has continued expansion projects allowing it to tap the sedimentary gold unit to greater depths; projections say that current technology will allow it to remain open until at least 2024.-JBBImage credit: http://www.reuters.com/article/2011/06/03/us-safrica-mine-deep-idUSTRE7523I620110603Read more:http://www.mining-technology.com/projects/mponeng/ http://wikimapia.org/5464887/Mponeng-Gold-Minehttp://www.infomine.com/minesite/minesite.asp?site=mponenghttp://www.ees.rochester.edu/ees119/reading2.pdf -- source link
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