Location | |
---|---|
Location | Larimer County, Colorado, 25 miles south of Laramie, Wyoming |
State | Colorado |
Country | United States |
Coordinates | 40°59′38″N105°30′18″W / 40.99389°N 105.50500°W Coordinates: 40°59′38″N105°30′18″W / 40.99389°N 105.50500°W |
Production | |
Products | Diamonds |
History | |
Opened | 1996 |
Closed | 2001 |
Kelsey Lake Diamond Mine is a defunct diamond mine in Colorado, USA. It is located in the State Line Kimberlite District, near the Wyoming border, and consists of nine kimberlite volcanic pipes, of which two were open pit mined.
At the time it was operating, it was the United States' only modern diamond mine, and only the second commercial diamond mining operation in North America, the first being in the Crater of Diamonds State Park, Arkansas which was mined in the early 1900s. [1]
Ever since diamonds had first been found in the State Line Kimberlite District in 1976 [2] , interest had been high in locating a viable commercial mining operation. Geologist Howard Coopersmith headed the Diamond Company L.N. which explored the feasibility of mining diamonds at the Kelsey Lake site. In 1995 Australian firm Redaurum acquired controlling interest in Diamond Co. and proceeded to lease mining rights for the land around Kelsey Lake . [3] Commercial output started in May 1996. After mining and selling approximately 200 carats worth of diamonds, Redaurum was sued by Union Pacific who had originally sold the land in 1896 but claimed that it held on to the mineral rights. [4] The two parties settled the lawsuit but in September 1997 Redaurum decided to liquidate its diamond properties to concentrate on exploration.
The mine was operated sporadically until the operation was acquired by McKenzie Bay International Ltd. in 2000. McKenzie bought the mine management firm Diamond Co. from Chapter 11 bankruptcy, transferred all its assets to a subsidiary, Great Western Diamond Co., and invested $2 million in new equipment for the mine. [5] In 2001, McKenzie tried to sell the mine to focus on mining vanadium after the price of that metal rose dramatically. [6] [7] However, due to a dispute with the landowner over royalty payments, the sale fell through and McKenzie was unable to find another buyer. [8] The mine ceased operations in 2001, and the site was fully reclaimed by 2006. [9]
Of the nine volcanic pipes found, three were reported to contain diamonds, and two (KL-1 and KL-2) were mined. These two pipes are each approximately 10.5 acres (4.2 ha) in area, are at least 350 feet (110 m) deep, and are situated 0.5 miles (0.80 km) apart. Bulk sampling during exploration in 1990 and 1991 recovered grades of 3.4 to 4.5 carats per hundred tons (cpht) for diamonds larger than 2 millimetres (0.079 in). Of the diamonds recovered, 50-65% were gem quality, and 25-30% of those were 1 carat (0.20 g) or larger. [10] [11]
While Redaurum ran the operation, the mine ran at half-capacity and produced almost 12,000 carats in 1996 and 9,000 carats in 1997. [12] [13] Due to Redaurum's African operations taking most of their time and capital, during their tenure the mine was unprofitable. In addition McKenzie Bay estimated that due to Redaurum's outdated equipment only 40% of the mined ore yielded diamonds, on the order of 1.5 cpht. [10]
When McKenzie Bay first acquired the mine, they estimated with their equipment improvements that they could recover 3.5 cpht from the ore. They also estimated that each of the two pipes being mined had about 340,000 carats worth of gems and could be profitably mined for about 10 years. The previous owners had a marketing agreement with local Denver diamond dealers to sell them Kelsey Lake diamonds for $115 per carat. If production had risen to the expected levels of 60,000 carats per year, McKenzie Bay expected to make $6.9 million annually. However, with the rising prices of vanadium McKenzie Bay shifted their focus away from Kelsey Lake and began mine reclamation procedures in 2003. [8] [10]
The price of diamonds depends mainly on the 4 C's of diamonds - carat, color, clarity, cut. Because of this pricing system large gemstones are worth more than a comparable mass of smaller stones. For this reason a successful diamond mining operation can't rely solely on the mass of carats recovered. The Kelsey Lake mine has produced some large stones. [14]
In 1994 a 14.2-carat, gem-quality white diamond was recovered. At the time the sixth-largest diamond ever found in North America, it was described as "almost flawless" and estimated to be worth $250,000. [3] [15]
In 1996 the largest diamond found at the mine was discovered. Named the "Colorado Diamond," it was a 28.3-carat (5.66 g) yellow stone and the fifth-largest diamond found in North America. The gem was cut and polished by legendary New York diamond cutter Bill Goldberg which yielded a 5.39-carat (1.078 g) faceted stone that sold for $87,500. [5] [16]
In July 1997, the company found two gem-quality stones weighing in at 16.3 carats and 28.2 carats. [14] The 28.2 carat diamond was cut into a 16.86-carat stone, one of the largest finished stones ever produced in North America. [17] The cut diamond is bigger than the gemstone produced from the "Uncle Sam" diamond, which was cut into a 12.42-carat stone. [18]
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. They are also the reason that diamond anvil cells can subject materials to pressures found deep in the Earth.
Tanzanite is the blue and violet variety of the mineral zoisite, caused by small amounts of vanadium. Tanzanite belongs to the epidote mineral group. Tanzanite is only found in Simanjiro District of Manyara Region in Tanzania, in a very small mining area near the Mererani Hills.
Crater of Diamonds State Park is a 911-acre (369 ha) Arkansas state park in Pike County, Arkansas, in the United States. The park features a 37.5-acre plowed field, the world's only diamond-bearing site accessible to the public. Diamonds have continuously been discovered in the field since 1906, including the graded-perfect Strawn-Wagner Diamond, found in 1990, and the Uncle Sam, found in 1924, which at over 40 carats is the largest diamond ever found in the United States.
The Argyle Diamond Mine was a diamond mine located in the East Kimberley region in the remote north of Western Australia. Argyle was at times the largest diamond producer in the world by volume, although the proportion of gem-quality diamonds was low. It was the only known significant source of pink and red diamonds, and additionally provided a large proportion of other naturally coloured diamonds, including champagne, cognac and rare blue diamonds.
The Ekati Diamond Mine ("Ekati") is Canada's first surface and underground diamond mine. It is located 310 km (190 mi) north-east of Yellowknife, Northwest Territories, and about 200 km (120 mi) south of the Arctic Circle, near Lac de Gras. Until 2014 Ekati was a joint venture between Dominion Diamond Mines (80%), and the two geologists who discovered kimberlite pipes north of Lac de Gras, Chuck Fipke and Stewart Blusson each holding a 10% stake in the mine, until Fipke sold his share to Dominion.
The Diavik Diamond Mine is a diamond mine in the North Slave Region of the Northwest Territories, Canada, about 300 km (190 mi) northeast of Yellowknife.
Gemesis Inc. was a privately held company located in New York City. The company grew synthetic diamonds using proprietary technology.
The Jwaneng diamond mine is the richest diamond mine in the world and is located in south-central Botswana about 120 kilometers (75 mi) west of the city of Gaborone, in the Naledi river valley of the Kalahari. Jwaneng, meaning "a place of small stones", is owned by Debswana, a partnership between the De Beers company and the government of Botswana. It is the second newest of four mines operated by the company, having begun operations in 1982.
The Murowa diamond mine is a diamond mine located in Mazvihwa, south central Zimbabwe, about 40 kilometres from the asbestos mining town of Zvishavane in the Midlands province. The mine is majority owned and operated by the Rio Tinto Group, which also owns the Argyle diamond mine in Australia and part of the Diavik Diamond Mine in Canada. The mine is a combination of open pit and underground construction; current estimates put construction costs at $61 million USD and mine reserves are 19 million tonnes of ore, with an ore grade of 0.9 carats (180 mg) per tonne.
The Williamson Diamond Mine is a diamond mine 23 kilometres (14 mi) northeast of Shinyanga in Tanzania; it became well known as the first significant diamond mine outside of South Africa. The kimberlite pipe was found in March 1940 and the mine established 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. A 2020 report by The Guardian said that high-quality pink diamonds from the mine could value up to $700,000 a carat.
Alrosa is a Russian group of diamond mining companies that specialize in exploration, mining, manufacture, and sale of diamonds. The company leads the world in diamond mining by volume. Mining takes place in Western Yakutia, the Arkhangelsk region, and Africa. Alrosa is Russia's leading diamond mining and distribution company, accounting for 95% of Russian diamond production and 27% of global diamond extraction.
The Mir mine, also called the Mirny mine, is an open pit diamond mine located in Mirny, Sakha Republic, in the Siberian region of eastern Russia. The mine is more than 525 meters deep, has a diameter of 1,200 m, and is one of the largest excavated holes in the world.
Canadian diamonds are diamonds which have been mined in any one of the Provinces and territories of Canada. Diamond-rich areas weren't commercially extracted in Canada until the early 1990s. For the first 60 years of the 20th century, diamonds originated from kimberlite pipes and alluvial deposits in places such as Africa and some from South America. Later, diamond discoveries were made in the Soviet Union. Since the 1990s, major diamond discoveries were made and mining operations began. Canadian diamonds play a large role in the world market of diamonds.
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The Attawapiskat kimberlite field is a field of kimberlite pipes located astride the Attawapiskat River in the Hudson Bay Lowlands, in Northern Ontario, Canada. It is thought to have formed about 180 million years ago in the Jurassic period when the North American Plate moved westward over a centre of upwelling magma called the New England hotspot, also referred to as the Great Meteor hotspot.
Petra Diamonds Ltd is a diamond mining group headquartered in Jersey. Petra own one of the world's most productive mines historically, the Cullinan Diamond Mine is famed for having produced the world's largest rough and polished diamond. The company is listed on the London Stock Exchange.
The Victor Mine was the first Canadian diamond mine located in Ontario, and De Beers' second diamond mine in Canada. It is located in the Northern Ontario Ring of Fire, in the James Bay Lowlands 90 kilometres (56 mi) west of Attawapiskat in the remote northern part of the province. In June 2005, the Attawapiskat First Nation voted in favour (85.5%) of ratifying the Impact Benefit Agreement (IBA). Construction of the mine began in February 2006 which created 3200 positions; mining and operations will create around 400 permanent positions. The Victor Mine is an open-pit mine, with a processing plant, workshops, and an airstrip located on site. By 2013–2014 royalties collected from De Beers Victor Mine amounted to $226. At that time De Beers was continuing to pay off its "$1 billion investment to build the mine and from now until it closes, the company expects to pay tens of millions of dollars in royalties." The mine completed mining and processing in 2019 and has moved to a shut-down phase including demolition of infrastructure and rehabilitation of the site.
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JSC «Severalmaz» is a Russian diamond mining company. It is a subsidiary of JSC "Alrosa" and holds a license for Europe's largest Lomonosov diamond mine, in Arkhangelsk Oblast, with reserves of 220 million carats of rough diamonds. Production in 2009 amounted to 500,000 carats of rough diamonds.