Photo taken by myself from the new viewpoint structure on 4th October 2009
Kimberley In its heyday, Kimberley was a lively, thriving mining town. Fortune seekers discovered a rich, rare kimberlite pipe which led to the growth of a tin-town around the ever-widening and deepening hole, which formed as they followed the trail of diamonds. The hole is now known as the Kimberley Big Hole - over 14.5 million carats of diamonds were extracted from it. The fascinating open-air Kimberley Mine Museum situated here is well worth a visit.
Diamond rushes in South Africa were often unpredictable; devastating on the environment and often disappeared as quickly as a Highveld storm. The first rush (1869) started when diamonds were discovered in the walls of a farmhouse. Diggers pulled the house down, pegged out the area around the house and eventually left the area with only a large hole in the ground.
About 2 years after the first, another rush started when diamonds were discovered on a small hillock close to the first discovery. The frantic rush caused the small hill (koppie) to disappear and to be replaced by a hole. However, this rush never came to an end and the hole grew bigger and bigger. Around the verges of The Big Hole" buildings sprang up and kept on expanding. The city of Kimberley was born.
Nobody could possibly have dreamed that the koppie would become the vigorous pit of the Kimberley Mine.
There was no end to the diamonds and people became unbelievably rich. According to stories successful diggers lit their cigars with bank notes whilst their women bath in champagne. Kimberley became the gathering place for the "new aristocracy" mainly swindlers, rogues, adventurers, Madames and other characters. From this two famous "diamond giants", Cecil John Rhodes and Barney Bernato emerged.
Kimberley became a very bright place. Races, lotteries, ballrooms, boxing booths, pubs, merry-go-rounds and dance halls flourished. It was the first city in Africa to have electrical streetlights. In 1887 a tramway started to operate. The Halfway and West End Hotels offer a ride-in bar service. Horsemen could order a drink without even dismounting.
The Big Hole When the diggers started to work the Kimberley diamond pipe, nobody knew how deep it would go. The deeper the workings the more complicated life became for the diggers. It resembled the inside of an ant heap. Up to 30 000 men were working day and night to clear the rubble and rock.
At the turn of the century the Hole was about 160 meters deep with an outside diameter of about 1200-meter. When mining stopped it was about 800 meters deep and more than 14 million carats of diamonds have been extracted.
The Diamond Giants Cecil John Rhodes was even more remarkable. He left the UK for South Africa to recover from tuberculosis and rushed to the diamond fields when the news of the first discoveries broke. He started his career by making and selling ice. In 1880 he formed the De Beers Mining Company.
When Barney Bernato sold out to Cecil Rhodes in 1888 for 5,4 million Pounds, he became a multi-millionaire. He left his job as barman in the music halls of London with his brother to become a diamond buyer in Kimberley. However, he was shrewd and made his fortune within 5 years. Bernato will always be remembered as one of the most flamboyant and audacious characters of diamond era.
He was a genius in negotiations and getting people to work for him. When Bernato sold out, he became the major shareholder of the world's largest diamond company and he was only 35 years old. Rhodes' energy was applied as statesman, developer, farmer and businessman and he is undoubtedly one of the great contributors to the development of the Southern Africa region.
The largest hand-dug excavation in the world The "Big Hole" was mined to a depth of about 800m [2625 feet] (depth of shaft = 1100m [3610 feet]). The distance from the surface to the layer of debris lying on top of the kimberlite pipe is about 215m [705 feet], including (in 2001) some 40m [131 feet] of water. It has a surface area of ±17 hectares [42 acres] and a perimeter of ±1.6km [1 mile]. It is the largest hand-dug excavation in the world. By 14 August 1914 22,7 billion kg [22.5 million tons] of rock had been excavated, yielding 2722 kg [2.7 tons] of diamonds. Underground mining was also eventually carried out at the Kimberley Mine, not just open pit mining.
Controversy In 2005, historian Steve Lunderstedt reported after doing intensive research that the Big Hole was actually not the biggest hand-made excavation. By studying historical records of several hand-dug mines, he discovered that the title belongs to the Jagersfontein Mine, another old South African diamond mine. He claims a comparison between the Big Hole and other mines was never made and it was just assumed to be the biggest and used as a selling point for tourism.
Volcanic pipes are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. They are considered to be a type of diatreme. Volcanic pipes are composed of a deep, narrow cone of solidified magma (described as "carrot-shaped"), and are usually largely composed of one of two characteristic rock types — kimberlite or lamproite. These rocks reflect the composition of the volcanoes' deep magma sources, where the Earth is rich in magnesium. Volcanic pipes are relatively rare. They are well known as the primary source of diamonds, and are mined for this purpose.
Formation Volcanic pipes form as the result of violent eruptions of deep-origin volcanoes. These volcanoes originate at least three times as deep as most other volcanoes, and the resulting magma that is pushed toward the surface is high in magnesium and volatile compounds such as water and carbon dioxide. As the body of magma rises toward the surface, the volatile compounds transform to gaseous phase as pressure is reduced with decreasing depth. This sudden expansion propels the magma upward at rapid speeds, resulting in a shallow supersonic eruption. A useful analogy to this process is the uncorking of a warm or shaken bottle of champagne.
Kimberlite pipes In kimberlite pipes, the eruption ejects a column of overlying material directly over the magma column, and does not form a large above-ground elevation as typical volcanoes do; instead, a low ring of ejecta known as a tuff ring forms around a bowl-shaped depression over the subterranean column of magma. Over time, the tuff ring may erode back into the bowl, leveling out the depression by filling it with washed-back ejecta. Kimberlite pipes are the source of most of the world's commercial diamond production, and also contain other precious gemstones and semi-precious stones, such as garnets, spinels, and peridot.
Lamproite pipes Lamproite pipes operate similarly to kimberlite pipes, except that the boiling water and volatile compounds contained in the magma act corrosively on the overlying rock, resulting in a broader cone of eviscerated rock (the ejection of this rock also forms a tuff ring, like kimberlite eruptions). This broad cone is then filled with volcanic ash and materials. Finally, the degassed magma is pushed upward, filling the cone. The result is a martini-glass shaped deposit of volcanic material (both solidified magma, and ejecta) which appears mostly flat from the surface.
Places to Visit
* The Big Hole Museum - the hole in itself is an extraordinary site and is surrounded by a reconstructed town dating from the days of Cecil Rhodes.
* McGregor Museum - displays a large selection of historical objects including a selection of Bushmen relics.
* Duggan-Cronin Gallery - houses 8000 photo's of African customs, exhibits of ethnological interest as well as beadwork.
* Humphreys Art Gallery - exhibits of South African and European art.
* Public Library - collection of Africana and material on the history of the diamond rush.
* South Africa's First Flying School - outdoor display of the county's first flying school.
* De Beers Mine - treatment and recovery plants are open to visitors.
To qualify:
1. Upload a photograph of any feature you liked during your visit. Send a photo of yourself or with your team and the GPSr at the viewpoint. THIS IS OPTIONAL AND NOT A REQUIREMENT ANYMORE.
2. What is the number and colour of your wrist band you received when paying your entrance fee?
3. Estimate the width, length and depth of the Big Hole.
4. What is the diamond bearing substance called and where did the name came from?
5. How much carats of diamonds were mined at the Kimberley's Big Hole?
Resources:
http://www.thebighole.co.za/
http://www.bdb.co.za/kimberley/museums.htm#big_hole
http://en.wikipedia.org/wiki/Big_Hole
http://en.wikipedia.org/wiki/Volcanic_pipe#Kimberlite_pipes
http://www.gemsutra.com/diamonds.html
I have earned GSA's highest level:
