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It is named after the town of Kimberley in South Africa, where the discovery of an 83.5-carat (16.70 g) diamond called the Star of South Africa in 1869 spawned a diamond rush and led to the excavation of the open-pit mine called the Big Hole. Previously, the term kimberlite has been applied to olivine lamproites as Kimberlite II, however this ...
There are a limited number of commercially available diamond mines currently operating in the world, with the 50 largest mines accounting for approximately 90% of global supply. [1] Diamonds are also mined alluvially over disperse areas, where diamonds have been eroded out of the ground, deposited, and concentrated by water or weather action.
Open-pit mines are used when deposits of commercially useful ore or rocks are found near the surface where the overburden is relatively thin. In contrast, deeper mineral deposits can be reached using underground mining. [2] Kittilä Gold Mine in Kittilä, Finland is the largest primary gold producer in Europe. [3] [4]
On 4 October 2006 the 120.6 grams (603 carats) white diamond, the Lesotho Promise was unearthed, which until the January 2018 discovery noted below was the largest reported find this century; at the time it was found it was the 15th largest diamond ever found. The stone is of an exceptional colour, rated D, the top colour for diamonds.
Bort-like heavily twinned diamond from Congo. Bort is commonly used as an abrasive. Smaller flakes and particles are used as an additive for scouring or polishing pastes and agents. Larger particles can be added to cutting, drilling and grinding tools to improve their lifespan and substantially increase their efficiency. [4]
Diavik Diamond Mine is an industrial complex set in a remote, subarctic landscape. [2] It consists of four kimberlite pipes associated with the Lac de Gras kimberlite field and is located on an island 20 km 2 (7.7 sq mi) in Lac de Gras informally known as East Island.
Exploration diamond drilling is used in the mining industry to probe the contents of known ore deposits and potential sites. By withdrawing a small diameter core of rock from the orebody, geologists can analyze the core by chemical assay and conduct petrologic , structural , and mineralogical studies of the rock.
Porphyry copper deposits represent an important resource and the dominant source of copper that is mined today to satisfy global demand. [6] Via compilation of geological data, it has been found that the majority of porphyry deposits are Phanerozoic in age and were emplaced at depths of approximately 1 to 6 kilometres with vertical thicknesses on average of 2 kilometres. [6]