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August 9, 2009

Seven of the World’s Most Amazing Holes

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Filed under : General Green
Kimberley Big Hole , South Africa


Kimberley is a city in South Africa, and the capital of the Northern Cape. It is located near the confluence of the Vaal and Orange Rivers. The town has considerable historical significance due its diamond mining past and siege during the Second Boer War. Notable personalities such as Cecil John Rhodes, made their fortune here, and the roots of the De Beers corporation can also be traced to the early days of the mining town.

As miners arrived in their thousands, the hill disappeared, and became known as the Big Hole. From mid-July 1871 to 1914, 50,000 miners dug the hole with picks and shovels, yielding 2,722 kg of diamonds. The Big Hole has a surface of 17 hectares (42 acres) and is 463 metres wide. It was excavated to a depth of 240m, but then partially infilled with debris reducing its depth to about 215 m; since then it has accumulated water to a depth of 40 m leaving 175 m visible. The underground Kimberly Mine was mined to a depth of 1097 metres. A popular local myth claims that it is the largest hand-dug hole on the world, however Jagersfontein Mine appears to hold that record. There is currently an effort in progress to register the Big Hole as a World Heritage Site.

A town, New Rush, was formed in the area, and was renamed to Kimberley on 5 July 1873, after the British Secretary of State for the Colonies at the time, John Wodehouse, 1st Earl of Kimberley. By this time Kimberley was the second largest town in South Africa, it had a total population of 13,000 whites and 30,000 blacks. The British, who had control of much of South Africa, were quick to annex the area of the diamond mine, which became the British colony of Griqualand West. The Boers were upset by this, because they wanted it to be a part of the Orange Free State as it lay inside the natural borders created by Orange and Vaal Rivers.

The various smaller mining companies were algamated by Barney Barnato into De Beers, and The Kimberley under Cecil Rhodes and Charles Rudd. In 1888, the two companies merged to form De Beers Consolidated Mines, which to this day today still retains a monopoly over the world’s diamond market.

Very quickly, Kimberley became the largest city in the area, mostly due to a massive African migration to the area from all over the continent. The immigrants were accepted with open arms, because the De Beers company was in search of cheap labour to help run the mines. Another group drawn to the city for money was prostitutes, from a wide variety of ethnicities who could be found in bars and saloons. It was praised as a city of limitless opportunity.

Five big holes were dug into the earth, which followed the kimberlite pipes, which are named after the town. Kimberlite is a diamond-bearing blue ground that sits below a yellow colored soil.The largest, The Kimberley mine or “Big Hole” covering 170 000 m², reached a depth of 240 m and yielded 3 tons of diamonds. The mine was closed in 1914, while three of the holes – Du Toitspan, Wesselton and Bultfontein – closed down in 2005.

Glory Hole, Monticello Dam, California

Monticello Dam is a dam in Napa County, California, United States.

Monticello Dam was constructed between 1953 and 1957. The dam is a medium concrete-arch dam with a structural height of 304 ft (93 m) and a crest length of 1023 ft (312 m). It contains 326,000 cubic yards (249,000 m³) of concrete.

The dam impounds Putah Creek to form Lake Berryessa, the second-largest lake in California. The capacity of the reservoir is 1.602 million acre-feet (1.98 km³). Water from the reservoir is supplied mostly to the North Bay area of San Francisco.

The Monticello Dam Powerplant was built at the dam in 1983 and has three generators. The electrical power is sent mostly to the North Bay area of San Francisco.

The dam is notable for its classic, uncontrolled spillway with a rate of 48,400 cubic feet per second (1370 m³/s) and a diameter at the lip of 87 feet (22 m).

Bingham Canyon Mine, Utah

The Bingham Canyon Mine is an open-pit mining operation extracting a large porphyry copper deposit southwest of Salt Lake City, Utah, USA, in the Oquirrh Mountains. It is owned by Rio Tinto Group, an international mining and exploration company headquartered in the United Kingdom. The copper operations at Bingham Canyon Mine are managed through Kennecott Utah Copper Corporation which operates the mine, a concentrator plant, a smelter, and a refinery. The mine has been in production since 1906, and has resulted in the creation of a pit over 0.75 miles (1.2 km) deep, 2.5 miles (4 km) wide, and covering 1,900 acres (7.7 km²). According to Kennecott, it is the world’s largest man-made excavation. It was designated a National Historic Landmark in 1966 under the name Bingham Canyon Open Pit Copper Mine.

Great Blue Hole, Belize

The Great Blue Hole is a large underwater sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll 100 kilometres (62 mi) from the mainland and Belize City. The hole is circular in shape, over 300 metres (984 ft) across and 125 metres (410 ft) deep. It was formed as a limestone cave system during the last glacial period when sea levels were much lower. As the ocean began to rise again, the caves flooded, and the roof collapsed.[2] Believed to be the world’s largest feature of its kind, the Great Blue Hole is part of the larger Belize Barrier Reef Reserve System, a World Heritage site of the United Nations Educational, Scientific and Cultural Organization (UNESCO).

Mirny Diamond Mine , Siberia, Russia

Mir Mine is an abandoned open pit diamond mine located in Mirny, Eastern Siberia. The mine is 525 metres (1,720 ft) deep and has a diameter of 1,200 m (3,900 ft). It was the first and one of the largest diamond pipes of the USSR. Mir Mine was discovered on June 13, 1955 by Soviet geologists Yuri Khabardin, Ekaterina Elagina and V.Avdeenko during the large Amakinsky Expedition in Yakut ASSR. It was operated for almost 50 years, finally closing on April 30, 2004, and while in operation, gave out 2 million carats annually. It takes trucks close to 2 hours to drive from the bottom to the top.

Diavik Mine, Canada

The Diavik Diamond Mine is a diamond mine in the North Slave Region of the Northwest Territories, Canada, about 300 kilometres (186 miles) north of Yellowknife. It has become an important part of the regional economy, employing 700, grossing C$100 million in sales, and producing 8 million carats (1600 kg) of diamonds annually. The area was surveyed in 1992 and construction began in 2001, with production commencing in January 2003. It is connected by an ice road and Diavik Airport with a 5,235-foot (1,596 m) gravel runway regularly accommodating Boeing 737 jet aircraft.

The mine is owned by a joint venture between the Harry Winston Diamond Corporation and Diavik Diamond Mines Inc., a subsidiary of Rio Tinto Group. The lifespan of the mine is expected to be 16 to 22 years.

The mine consists of three kimberlite pipes associated with the Lac de Gras kimberlite field and is located on an island 20 square kilometres (8 sq mi) in Lac de Gras and is informally called East Island. It is about 220 kilometres (137 mi) south of the Arctic Circle.

In 2006 the ice road from Yellowknife to the Diavik mine, and neighboring mines, froze late and thawed early. The Diavik mine was unable to truck in all the supplies needed for the rest of 2006 before the road closed and arrangements had to be made to bring the remainder of the supplies in by air.

On July 5, 2007 a consortium of seven mining companies, including Rio Tinto, announced they are sponsoring environmental impact studies to construct a deep-water port in Bathurst Inlet. Their plans include building a 211 km (131 mi) road connecting the port to their mines. The port would serve vessels of up to 25,000 tonnes.

Sinkhole in Guatemala

A rupture in the underground stormwater drain system opened a huge sinkhole on February 23, killing three people and bringing down twelve houses in Guatemala City.

Teenagers Irma and David Soyos and their father, 53-year old Domingo Soyos were killed when their house collapsed into the sinkhole. Nearly a thousand people were evacuated from the San Antonio neighborhood after the collapse.

Wikinews interviewed Eric Haddox, a civil engineer who has visited the site of the sinkhole and spoken to the engineers working on fixing the drain. Mr. Haddox, who specialises in the building of earthworks, roads, water supply and sewage systems, and is working as a missionary in Guatemala, visited the site following the collapse to help in the recovery effort.

Mr. Haddox told us that the size of the hole is much smaller than the 330 feet depth originally reported and that the erosion causing the collapse is believed to have happened over a long time, and not just during the recent rains as initially suspected.

There are also concerns that a four-story building less than a metre from the edge of the hole may collapse as the earth under the building continues to be eroded.

credited to wikipedia

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