Cullinan Mine, Cullinan, City of Tshwane Metropolitan Municipality, Gauteng, South Africai

Regional Level Types
Cullinan Mine	Mine
Cullinan	Town
City of Tshwane Metropolitan Municipality	Municipality
Gauteng	Province
South Africa	Country

A diamond mine on farm Elandsfontein 480 JR, in a kimberlite pipe dated 1,200 million years old, previously owned by De Beers, with a cross-section of 32 ha at the surface, the pipe is the largest ever found in South Africa.

It was discovered in 1902 as a consequence of prospecting for heavy minerals in nearby rivers, where diamonds were found and traced back to their source in the hills at Cullinan, 20-25 miles east of Pretoria. The mine started producing in 1903 and was operated as an open-pit mine until 1932 when it had to close due to the economic depression.

Ore extraction has been by underground mining methods since 1946. Ore extraction has varied between 2 and 5 Mt per annum and ore treatment between 2 and 7 Mt per annum.

In 2005, it produced 1.3 million carats from 4.6 million tons of ore. The workings are 2,900 feet by 1,400 feet across and more than 700 feet deep.

The mine was renamed ‘Cullinan’ as part of its centenary celebrations and to link the mine to the illustrious heritage of the Cullinan diamond, which provided the two main polished diamonds within the British Crown Jewels (the 530-carat Great Star of Africa and the 317 carat Lesser Star of Africa).

Petra Diamonds initially acquired a 37% interest in the Cullinan mine from De Beers in 2008 but increased its direct interest in the mine to 74% in late 2009 when it acquired Al Rajhi’s holding in the mine. Petra Diamonds continues to mine the underground resources using block cave mining methods.

The mine is famous for its large, high-quality gem diamonds including Type II stones. The world's largest diamond, the 3106 ct Cullinan was discovered in 1905.

The mine has produced over 800 stones weighing more than 100 carats, 140 stones more than 200 carats and around 25% of all diamonds weighing more than 400 carats.

Cullinan is also renowned as the world’s most important source of blue diamonds, providing the collection of 11 rare blues displayed in 2000 at London’s Millennium Dome alongside the Millennium Star and which included the fancy vivid blue ‘Heart of Eternity’ (27 carats polished).

Recent notable stones were the 599 ct "Centenary" and the 1083 ct "Unknown Brown". The diamond grade increases with depth, possibly as a result of diminishing proportions of country-rock inclusions. Among researchers, the mine is best known for its mantle-derived rocks and minerals, of which the garnet harzburgites and lherzolites have received the most attention.

Other Databases

Wikipedia:	https://en.wikipedia.org/wiki/Premier_Mine
Wikidata ID:	Q2576349

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References