The Cullinan Diamond Mine is renowned as a source of large, high-quality gem diamonds, including Type II stones, as well as being the world’s most important source of very rare blue diamonds. Cullinan earned its place in history with the discovery of the Cullinan diamond in 1905, the largest rough gem diamond ever found at 3,106 carats, which was cut to form the two most important diamonds in the British Crown Jewels. Many of the world’s most famous diamonds herald from Cullinan, and it continues to produce world-class diamonds under Petra’s stewardship. The Cullinan orebody contains a major diamond resource of 195 Mcts, suggesting a potentially long life for the operation of +50 years. The Cullinan kimberlite pipe was discovered in 1902 and open pit mining commenced at the ‘Premier’ mine (as it was then known) in 1903. 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. 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).