The Cullinan Diamond Mine – Yesterday, Today, and Tomorrow

History and Development

The Premier Diamond Mining Company was founded by Thomas Cullinan (later Sir Thomas) in 1902, near the end of the second Boer War (South African War 1899 – 1902). The land was originally part of the Cornelis Minnaar Farm and was purchased for a sum total of £52,000 by Thomas. The company was first registered on the 6th November 1902 as the Premier Syndicate but was later re-registered as the Premier Transvaal Diamond Mining Company Ltd. on 1st December, 1902.

Cullinan Village was established in 1903 to provide housing and services for mine employees and is located approximately 40 kilometers east of the South African capital of Pretoria in the Gauteng Province.

One of the most notable and famous diamond discoveries occurred at the Premier Diamond Mining Company on 26th January, 1905 when a young miner named Thomas Evan Powell brought a large 3106.75ct rough gem quality diamond to his surface manager Frederick Wells. The diamond is the largest gem-quality diamond ever found and is famously known as the Cullinan Diamond.

In 1910 Thomas Cullinan was knighted in recognition of his contribution to the diamond industry and in 1917 De Beers Consolidated Mines acquired a controlling interest in the mine but later sold it to a consortium in 2008. Today, Petra Diamonds is the technical operator of the mine on behalf of the business consortium (PDCC – Petra Diamonds Cullinan Consortium) as they have 74% interest in the company.

In 2003 the mine was renamed The Cullinan Diamond Mine to celebrate 100 years since its initial opening.

Modern Day Mining Techniques

The Cullinan Kimberlite pipe is situated on the stable Kaapvaal Craton which is estimated to be approximately 3 billion years old. It is the world’s second largest diamond resource of 181.4 million carats (total resource base of 203.3 million carats). The pipe itself resembles a carrot shape and stretches 32 hectares at the surface (roughly 30 soccer pitches) and stretches 1,073 meters deep.

From 1902 to its forced closure in 1932 due to the economic depress, the mine operated as an open-pit with a depth of 189 meters. When the mine re-opened again in 1946 it started production under various mining methods. The early 1970’s utilized cave mining with the early 1980’s performing sub-level open stoping. Today, the mine is at a depth of 747 meters and is using mechanized trackless block-cave mining as their main method of diamond ore extraction.

Cullinan Diamond History and Notable Discoveries

In 1905, the mine famously uncovered the 3106.75ct rough Cullinan Diamond. The rough diamond measured 10 cm long by 6 cm high and 5 cm thick and weighed in at 621.2 grams. The rough diamond was sold to the Transvaal government for £150,000.00 who then gifted it to King Edward VII on his 66th birthday on November 9th, 1907. It has since been split and cut into 9 major stones and 96 smaller stones. These 9 major diamonds and their general history are detailed below:

The Cullinan I – Also known as the Great Star of Africa, is a pear shape weighing 530.20 carats and is currently set in the Royal Sceptre.

The Cullinan II – Also known as the Lesser Star of Africa, is a rectangular cushion shape diamond weighing 317.40 carats and is currently set in the 鑽石樓上鋪 center of the Imperial State Crown of Great Britain.

The Cullinan III – A pear shape weighing 94.40 carats originally set in the orb of Queen Mary’s Crown. It is currently hanging from the Cullinan IV in a brooch.

The Cullinan IV – A square cushion weighing 63.60 carats originally set in the band of Queen Mary’s crown. It currently forms part of a brooch together with the Cullinan III.

The Cullinan V – A heart shape weighing 18.50 carats originally mounted in a brooch for Queen Mary but is now set as a replacement for the Koh-i-Noor diamond which was used in a new crown made for Queen Elizabeth (Queen Mother) in 1937.

The Cullinan VI – A marquise shape weighing 11.50 carats originally given by Edward VII to Queen Alexandra. After his death the Queen then gave the stone to Queen Mary who had it set as a pendant hanging from the diamond and emerald necklace in the Delhi Durbar Parure.

The Cullinan VII – A marquise shape weighing 8.80 carats that is currently mounted as a pendant drop on a diamond brooch containing the Cullinan VIII. It is part of the stomacher of the Delhi Durbar Parure.

The Cullinan VIII – A rectangular cushion shape weighing 6.8 carats that is currently mounted as the center diamond on the same brooch as the Cullinan VII.

The Cullinan IX – A pear shape weighing 4.39 carats and is set as a bezel in a ring.

The Cullinan Diamond Mine has recently uncovered other large notable diamonds. In May of 2008 a 460 carat rough diamond was found. The rough was then cut to a 101.27 shield-shaped diamond with 92 brilliant facets. The diamond is internally flawless and was sold at Chrisities in Hong Kong for $6.2 million dollars. This diamond is the largest colorless diamond to appear on auction for the last 18 years.

In September of 2009 another large diamond discovery at the mine was made. A whopping 507 carat diamond was found and is currently ranked as one of the 20 largest high quality diamonds ever found. Petra sold this diamond for $35.3 million on 26 February 2010 and broke the record for the highest price every paid for a rough diamond.

The Cullinan Diamond Mine Global Diamond Production

In July 2008, De Beers Consolidated Mines (DBCM) sold its Cullinan mine for R1-billion to a consortium comprised of Petra Diamonds, Al Rajhi Holdings, and Thembinkosi Mining. The mine has produced more than 25% of all the world’s diamonds that weigh more than 400 carats and is the only significant source of the very rare and valuable blue diamonds.


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