The Premier Mine is located on a rich diamond-bearing kimberlite pipe at Cullinan. The pipe is carrot-shaped volcanic neck originating from great depths within the Earth and is the largest in South Africa. The name “kimberlite’ comes from the city of Kimberley in the Northern Cape from where this very unusual rock type was first mined in 1871 as “yellow ground” at what is now Kimberley’s “Big Hole”.
Thomas Cullinan (later Sir Thomas), a successful Johannesburg businessman and amateur geologist, discovered the Premier kimberlite in 1898. His attention was drawn to the area by the alluvial diamonds that were being found in nearby stream. However doing business with the owners was impossible until after the Anglo-Boer War in 1902. Mining started in 1903 and in the first year of operation over 100 000 carats were recovered. It is still one of South Africa’s largest and most productive diamond mines. All production is now from underground.
The Premier pipe is by far the largest of a cluster of 11 kimberlites in the area. It has been dated at 1200 million years, unusually old for kimberlites. The original surface area was 32 ha and the “Big Hole” is now nearly 1000 m long and 400 m wide at the surface, and narrowing down to 21 ha at the -500 m level. It was mined to a depth of 190 m from surface and is now being mined by underground block caving. Come and enjoy a surface tour of a working diamond mine. The Cullinan Mine has produced some of the world’s large, high quality gemstones and the largest diamond in the world (the Cullinan Diamond [3106-ct]) was found there.