Williamson diamond mine
Encyclopedia
The Williamson Diamond Mine (also known as the Mwadui mine) is a diamond mine
south of Mwanza
in Tanzania
; it became well known as the first significant diamond mine outside of South Africa
. The mine was established in 1940 by Dr. John Williamson
, a Canadian
geologist
, and has been continuous operation since then, making it one of the oldest continuously operating diamond mines in the world. Over its lifetime it has produced over 19 million carats (3,800 kg) of diamonds. The Williamson mine, once owned by its namesake Dr. Williamson and later nationalized
by the government of Tanzania, is now majority owned by Petra Diamonds
(75 % ownership), with the government of Tanzania owning the remaining 25 %.
to recover missed diamonds, and gravel
mining both on the property and adjacent to the property where gravel has been alluvially
deposited. The open pit mining and tailings re-treatment are the largest of the four operations. The mine currently employs about 1,100 staff, mostly Tanzanians.
on the shores of Lake Victoria
in Tanzania, in the Shinyanga
region. Dr. Williamson, the discoverer of the site, first owner and namesake of the mine, named the site "Mwadui" after a local chief; "Williamson" and "Mwadui" are now virtually synonymous in the diamond mining world.
. This is a dramatic decrease from its production in the mine's early life; during the first 25 years of operation, average ore grade was about 30 carats (6 g) per hundred tons (60 mg/t); in the first few years of full operation grades were as high as 62 carats (12.4 g) per hundred tons (124 mg/t), or 10 times the ore realized today. Production in the 1950s and 1960s was usually between 500,000 and 750,000 carats (100 and 150 kg) per year; the peak year of production was 1966, when 924,984 carats (185 kg) were produced. Today production levels for all Williamson mine diamond recovery activities is about 300,000 carats (60 kg) per year.
Notable stones produced at the Williamson mine include 54 carat (10.8 g) flawless
pink
diamond (presented to then-Princess Elizabeth
and Prince Philip
upon their wedding in 1947), and a 388 carat (77.6 g) diamond found in 1990.
in the region. In 1940 he discovered the Mwadui kimberlite pipe; over the next several years he developed the mine, although he was hindered by difficulty in procuring equipment and raising funds due to World War II
. By the 1950s he had developed the Williamson diamond mine into the first significant diamond mine in Tanzania, with state-of-the-art equipment and a labor force of several thousand. The mine was noted for numerous technical innovations in diamond mining which were developed under Williamson's watch. Williamson closely managed the mine until his death in 1958 at the age of 50.
Williamson's heirs sold the mine for about £4 million GBP
to an equal partnership between De Beers
and the colonial
government of Tanganyika
on August 13, 1958. In 1971, a decade after Tanzania's independence, the government nationalized the mine. Although details are unknown, De Beers and other diamond industry players speculate that mine performance deteriorated significantly in the 1980s under government management. Suspected causes of this are a decrease in ore grade as the mine's richer deposits were worked out, loss of skilled foreign management and engineering staff, a bloated labor force resulting from government employment efforts, and inadequate capital investment in the mine's equipment. Perhaps as a result of this poor performance, Tanzania invited De Beers to purchase back into the mine, which the company decided to do. In 1994 De Beers bought 75% of the Williamson mine, with Tanzania retaining the remaining shares.
Since 1994, De Beers has acted to improve the performance of the Williamson diamond mine by trimming work force, making needed capital investments in equipment, and bringing in expertise in technology, technique, and exploration. Although the mine is still viewed as a marginal performer due to its low ore grade, De Beers has identified several possible avenues for development that would keep the mine operating well into the future.
Diamond Mine
Diamond Mine is the second album by Blue Rodeo, released in 1989. It includes several instrumental interludes by Bob Wiseman between songs.-Track listing:All songs by Greg Keelor and Jim Cuddy.#"Swells"#"God and Country" – 3:32#"How Long" – 3:59...
south of Mwanza
Mwanza
Mwanza is a mid-sized port city on the southern shores of Lake Victoria in northwestern Tanzania. With an urban population of 1.2 million and a metropolitan population of 2 million, it is Tanzania's second largest city, following Dar es Salaam and ahead of other major Tanzanian cities of Arusha,...
in Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...
; it became well known as the first significant diamond mine outside of South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. The mine was established in 1940 by Dr. John Williamson
John Williamson (geologist)
John Thoburn Williamson was a Canadian geologist famous for establishing the Williamson diamond mine in present-day Tanzania....
, a Canadian
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
geologist
Geologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...
, and has been continuous operation since then, making it one of the oldest continuously operating diamond mines in the world. Over its lifetime it has produced over 19 million carats (3,800 kg) of diamonds. The Williamson mine, once owned by its namesake Dr. Williamson and later nationalized
Nationalization
Nationalisation, also spelled nationalization, is the process of taking an industry or assets into government ownership by a national government or state. Nationalization usually refers to private assets, but may also mean assets owned by lower levels of government, such as municipalities, being...
by the government of Tanzania, is now majority owned by Petra Diamonds
Petra Diamonds
Petra Diamonds Ltd. is a leading diamond mining group. It is headquartered in Jersey, and is the largest diamond producer listed on Alternative Investment Market, part of the London Stock Exchange. It currently operates in South Africa, Tanzania, and Botswana, and previously worked on projects in...
(75 % ownership), with the government of Tanzania owning the remaining 25 %.
Description
The Williamson diamond mine is a large open pit mine currently about 90 meters (300 ft) deep. Diamond mining operations at the Williamson diamond mine are composed of four distinct activities: mining of the pit, re-treatment of tailingsTailings
Tailings, also called mine dumps, slimes, tails, leach residue, or slickens, are the materials left over after the process of separating the valuable fraction from the uneconomic fraction of an ore...
to recover missed diamonds, and gravel
Gravel
Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel can be sub-categorized into granule and cobble...
mining both on the property and adjacent to the property where gravel has been alluvially
Alluvium
Alluvium is loose, unconsolidated soil or sediments, eroded, deposited, and reshaped by water in some form in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel...
deposited. The open pit mining and tailings re-treatment are the largest of the four operations. The mine currently employs about 1,100 staff, mostly Tanzanians.
Location
The mine is located about 160 kilometres (99.4 mi) south of the town of MwanzaMwanza
Mwanza is a mid-sized port city on the southern shores of Lake Victoria in northwestern Tanzania. With an urban population of 1.2 million and a metropolitan population of 2 million, it is Tanzania's second largest city, following Dar es Salaam and ahead of other major Tanzanian cities of Arusha,...
on the shores of Lake Victoria
Lake Victoria
Lake Victoria is one of the African Great Lakes. The lake was named for Queen Victoria of the United Kingdom, by John Hanning Speke, the first European to discover this lake....
in Tanzania, in the Shinyanga
Shinyanga
Shinyanga, also known as Shinyanga mji in the local Swahili language, is a city in northern Tanzania. The city is the location of the regional headquarters of Shinyanga Region as well as the district headquarters of Shinyanga Urban District...
region. Dr. Williamson, the discoverer of the site, first owner and namesake of the mine, named the site "Mwadui" after a local chief; "Williamson" and "Mwadui" are now virtually synonymous in the diamond mining world.
Geology
The most important geological feature of the Williamson diamond mine is the kimberlite pipe on which it is located. At 1.46 square kilometers in area at surface level, it ranks as the largest economically exploitable diamond-bearing volcanic pipe in the world. Recent exploratory drill cores conducted by De Beers have indicated that the pipe is a pyroclastic kimberlite, not a hypabyssal kimberlite as earlier suspected. This indicates that it may be possible to extend the current 90-meter deep open pit to as much as 350 meters deep, and continue down even further with underground mining operations. However, a review of mine operations and long term plans continues, and any discussion of deep expansion of the open pit is speculative in nature.Production
The Williamson diamond mine is now characterized by low ore grade of about 6 carats (1,200 mg) per hundred tons (12 mg/t) of oreOre
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
. This is a dramatic decrease from its production in the mine's early life; during the first 25 years of operation, average ore grade was about 30 carats (6 g) per hundred tons (60 mg/t); in the first few years of full operation grades were as high as 62 carats (12.4 g) per hundred tons (124 mg/t), or 10 times the ore realized today. Production in the 1950s and 1960s was usually between 500,000 and 750,000 carats (100 and 150 kg) per year; the peak year of production was 1966, when 924,984 carats (185 kg) were produced. Today production levels for all Williamson mine diamond recovery activities is about 300,000 carats (60 kg) per year.
Notable stones produced at the Williamson mine include 54 carat (10.8 g) flawless
Diamond clarity
Diamond clarity is a quality of diamonds relating to the existence and visual appearance of internal characteristics of a diamond called inclusions, and surface defects called blemishes. Clarity is one of the four Cs of diamond grading, the others being carat, color, and cut...
pink
Diamond color
A chemically pure and structurally perfect diamond is perfectly transparent with no hue, or color. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impurities and/or structural defects in the crystal lattice...
diamond (presented to then-Princess Elizabeth
Elizabeth II of the United Kingdom
Elizabeth II is the constitutional monarch of 16 sovereign states known as the Commonwealth realms: the United Kingdom, Canada, Australia, New Zealand, Jamaica, Barbados, the Bahamas, Grenada, Papua New Guinea, the Solomon Islands, Tuvalu, Saint Lucia, Saint Vincent and the Grenadines, Belize,...
and Prince Philip
Prince Philip, Duke of Edinburgh
Prince Philip, Duke of Edinburgh is the husband of Elizabeth II. He is the United Kingdom's longest-serving consort and the oldest serving spouse of a reigning British monarch....
upon their wedding in 1947), and a 388 carat (77.6 g) diamond found in 1990.
History
The diamond industry of Tanzania in the 1930s was characterized by a scattering of very small mining operations that were insignificant in the economic makeup of the country. Dr. Williamson was hired by one of these operations, the Mabuki diamond mine, in 1938 and used it as his base for diamond prospectingProspecting
Prospecting is the physical search for minerals, fossils, precious metals or mineral specimens, and is also known as fossicking.Prospecting is a small-scale form of mineral exploration which is an organised, large scale effort undertaken by mineral resource companies to find commercially viable ore...
in the region. In 1940 he discovered the Mwadui kimberlite pipe; over the next several years he developed the mine, although he was hindered by difficulty in procuring equipment and raising funds due to World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. By the 1950s he had developed the Williamson diamond mine into the first significant diamond mine in Tanzania, with state-of-the-art equipment and a labor force of several thousand. The mine was noted for numerous technical innovations in diamond mining which were developed under Williamson's watch. Williamson closely managed the mine until his death in 1958 at the age of 50.
Williamson's heirs sold the mine for about £4 million GBP
Pound sterling
The pound sterling , commonly called the pound, is the official currency of the United Kingdom, its Crown Dependencies and the British Overseas Territories of South Georgia and the South Sandwich Islands, British Antarctic Territory and Tristan da Cunha. It is subdivided into 100 pence...
to an equal partnership between De Beers
De Beers
De Beers is a family of companies that dominate the diamond, diamond mining, diamond trading and industrial diamond manufacturing sectors. De Beers is active in every category of industrial diamond mining: open-pit, underground, large-scale alluvial, coastal and deep sea...
and the colonial
Colony
In politics and history, a colony is a territory under the immediate political control of a state. For colonies in antiquity, city-states would often found their own colonies. Some colonies were historically countries, while others were territories without definite statehood from their inception....
government of Tanganyika
Tanganyika
Tanganyika , later formally the Republic of Tanganyika, was a sovereign state in East Africa from 1961 to 1964. It was situated between the Indian Ocean and the African Great Lakes of Lake Victoria, Lake Malawi and Lake Tanganyika...
on August 13, 1958. In 1971, a decade after Tanzania's independence, the government nationalized the mine. Although details are unknown, De Beers and other diamond industry players speculate that mine performance deteriorated significantly in the 1980s under government management. Suspected causes of this are a decrease in ore grade as the mine's richer deposits were worked out, loss of skilled foreign management and engineering staff, a bloated labor force resulting from government employment efforts, and inadequate capital investment in the mine's equipment. Perhaps as a result of this poor performance, Tanzania invited De Beers to purchase back into the mine, which the company decided to do. In 1994 De Beers bought 75% of the Williamson mine, with Tanzania retaining the remaining shares.
Since 1994, De Beers has acted to improve the performance of the Williamson diamond mine by trimming work force, making needed capital investments in equipment, and bringing in expertise in technology, technique, and exploration. Although the mine is still viewed as a marginal performer due to its low ore grade, De Beers has identified several possible avenues for development that would keep the mine operating well into the future.