[USMA:37194] Re: Site about diamond mine in Russia uses SI

[Martin Vlietstra]

I am not entirely convinced about this being the world's biggest hole.  I believe that it might be the Cullinan mine in South Africa (where the Star of Africa, one of the Crown Jewels was found).  A quick comparison suggests that the mining technique used by the Russians might have resulted in a larger hole, but only because more useless rock was removed to make the spiral roadway.  Anyway, the two mines are comparable.   If you visit http://www.geosites.co.za/premier.htm, you will find   << 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. Premier Mine is world-famous for the discovery of the massive Cullinan diamond in 1905. It was found in the early surface workings and is still by far the largest gem diamond ever found. It weighed 3106 carat or 621 grams and was 10 cm long, 6 cm high and 5 cm thick. The stone was named after Thomas Cullinan and was sent to Amsterdam for splitting and cutting. The original stone was cut into nine large stones and 96 smaller brilliants. The four largest stones are known as The Stars of Africa". All nine large stones are either in the Crown Jewels or are owned by the British Royal Family.     >>   I must declare an interest, I worked for de Beers between 1970 and 1978 and once visited the mine as part of my duties. ----- Original Message ----- From: Mike Millet To: U.S. Metric Association Sent: Wednesday, July 26, 2006 12:22 AM Subject: [USMA:37145] Site about diamond mine in Russia uses SI Here are some pictures of a diamond mine in Russia. Although I'm not sure about it's claim to be "the biggest hole in the world" it's fun to read if only because every unit on the page is in SI. http://www.sreedhara.com/2006/07/25/the-biggest-hole-in-the-world-great-photos/ Mike -- "The boy is dangerous, they all sense it why can't you?"