The Argyle diamond mine (16°42′44″S, 128°23′51″E) is a diamond mine located in the north-east of Western Australia. The Argyle mine is the largest diamond producer in the world by volume, although due to the low proportion of gem-quality diamonds, is not the leader by value. It is the only known significant source of pink diamonds, producing 90 to 95% of the world's supply. The Argyle diamond mine is also notable for being the first commercial diamond mine exploiting a volcanic pipe of lamproite, rather than the more usual kimberlite pipe. The mine is owned by the Rio Tinto Group, a diversified mining company which also owns the Diavik Diamond Mine in Canada and the Murowa diamond mine in Zimbabwe. For other uses, including the shape â—Š, see Diamond (disambiguation). ... The El Chino Mine located near Silver City, New Mexico is an open-pit copper mine This article is about mineral extraction. ... Emblems: Fauna-Black Swan Flora-Kangaroo Paw Capital = Perth Motto: Cygnis Insignis (Distinguished by its swans) Slogan or Nickname: Wildflower State Other Australian states and territories Capital {{{Capital}}} Government Governor Premier Const. ... When Argyle does not refer to the Duke of Argyle, it may refer to things or places: Plymouth Argyle is an English association football team. ... Volcanic Pipe Volcanic pipes are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. ... Lamproite is a peralkaline volcanic rock. ... Hewn kimberlite core sample from the James Bay Lowlands region of Northern Ontario, Canada. ... Rio Tinto is a multinational mining and resources group founded originally in 1873. ... The Diavik Diamond Mine is a very large diamond mine located in the Northwest Territories, about 300 km north of Yellowknife. ... The Murowa diamond mine is a diamond mine located in south central Zimbabwe, about 40 kilometers from Zvishavane. ...

Description

A false-color NASA image of the Argyle mine. Blue colors show the location of the mine and its depressed elevation as a result of the open pit mining technique.

The mine covers about 450,000 square metres (110 acres), stretching in a mostly linear shape about 1600 metres (5,200 ft) long and 150 to 600 metres (500 to 2,000 ft) wide. The mine is of open pit construction, and reaches about 600 metres (1,900 ft) deep at its deepest point. Image File history File links Download high resolution version (1313x802, 264 KB)False color image of the Argyle diamond mine in Western Australia, Australia. ... Image File history File links Download high resolution version (1313x802, 264 KB)False color image of the Argyle diamond mine in Western Australia, Australia. ... This article or section is missing references or citation of sources. ... A square metre (US spelling: square meter) is by definition the area enclosed by a square with sides each 1 metre long. ... The metre, or meter, is a measure of length, approximately equal to 3. ... The El Chino mine located near Silver City, New Mexico is an open-pit copper mine Open-pit mining refers to a method of extracting rock or minerals from the earth by their removal from an open pit or borrow. ...

Location

The Argyle diamond mine is located in the Kimberley region in the far northeast of the Australian state of Western Australia. It is located to the southwest of Lake Argyle in the Matsu Ranges, about 550 kilometres (340 miles) southwest of Darwin. Because the mine is located about 120 kilometres (75 miles) from the nearest settlement (Kununurra), a complete residential camp has been constructed on site. Most of the 520 workers commute from Perth (over 2,000 kilometres, or 1,200 miles, away) for alternating two week shifts at the mine. The mine has encouraged local employment and has a large number of indigenous local people working within the mine. The Kimberley is one of the nine regions of Western Australia, consisting of the local government areas of Broome, Derby-West Kimberley, Halls Creek and Wyndham-East Kimberley. ... The regions of Western Australia are distinct geographic areas of Western Australia, defined by the government of Western Australia for purposes of economic development administration. ... Australia, having a federal system of government, is divided into states and territories. ... Emblems: Fauna-Black Swan Flora-Kangaroo Paw Capital = Perth Motto: Cygnis Insignis (Distinguished by its swans) Slogan or Nickname: Wildflower State Other Australian states and territories Capital {{{Capital}}} Government Governor Premier Const. ... Lake Argyle from space, August 1985 Lake Argyle is Australias largest man-made lake, part of the Ord River Scheme, near the East Kimberley (Western Australia) town of Kununurra, located on the Kimberley Plateau. ... Darwin is the territorial capital and most populous city of the Northern Territory. ... Kununurra is a town in north Western Australia located at the eastern side of the Kimberley Region close to the border with the Northern Territory. ... Perth is the state capital and most populous city of Western Australia. ...

Geology

The mine is the first commercial diamond mine (except alluvial mining operations) not located on a kimberlite pipe.the mines in the kimberly are poopy heads. The pipe is named "AK-1", although it is commonly simply called the "Argyle pipe". Alluvium is soil land deposited by a river or other running water. ... Hewn kimberlite core sample from the James Bay Lowlands region of Northern Ontario, Canada. ...

The volcanic pipe is a diatreme, composed of olivine lamproite, present as tuff and lava. Peripheral volcanic facies suggest the lamproite eruption formed a maar. At the margins of the volcanic pipe the lamproite is mixed with a volcanic breccia containing shattered wall rock fragments mixed and milled by the eruption. Minerals in the marginal facies include zeolite minerals, micas, kaolinite and clays, typical of post-eruption hydrothermal circulation. A Diatreme is a volcanic pipe or feature formed by a gas or volatile rich explosive magma. ... Olivine The mineral olivine is a magnesium iron silicate with the formula (Mg,Fe)2SiO4 in which the ratio of magnesium and iron varies between the two endmembers of the series: forsterite (Mg-rich) and fayalite (Fe-rich). ... Lamproite is a peralkaline volcanic rock. ... This page describes the geological feature. ... Breccia, derived from the Latin word for broken, is a sedimentary rock composed of angular fragments in a matrix that may be of a similar or a different material. ... Zeolite Zeolites (Greek, zein,to boil;lithos,a stone) are minerals that have a porous structure. ... rock with mica Mica sheet mica flakes The mica group of minerals includes several closely related materials having highly perfect basal cleavage. ... Kaolin Kaolinite (Aluminium Silicate Hydroxide) Kaolinite is a clay mineral with the chemical composition Al2Si2O5(OH)4. ... Hydrothermal circulation in the oceans is the passage of the water through mid-ocean Ridge (MOR) systems. ...

Diamonds are found within the intact core of the volcanic pipe, as well as within some of the marginal breccia facies and maar facies. However, some diamonds are considered to have been resorbed during the post-eruption cooling of the pipe and converted to graphite. Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γραφειν: to draw/write, for its use in pencils) is one of the allotropes of carbon. ...

The diatreme pipe formed by explosive eruption of the lamproite magma through a zone of weakness in the continental crust. The continental crust is the layer of granitic, sedimentary and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves. ...

The diamonds found at the Argyle pipe have been dated to about 1.58 billion years of age, while the volcano which created the pipe is aged between 1.1 and 1.2 billion years old. This represents a relatively short period during which diamond formation could have taken place (around 400 million years), which may explain the small average size and unusual physical characteristics of Argyle diamonds. Diamonds found in the Argyle pipe are predominantly eclogitic, meaning that the carbon is of organic origin (see Natural history of diamonds). Eclogite is a coarse-grained, mafic-to-ultramafic grouping of metamorphic rocks of special interest on account of the variety of minerals they contain and their microscopic structures and geological relationships. ... For other uses, including the shape â—Š, see Diamond (disambiguation). ...

In addition to the pipe itself, there are a number of semi-permanent streams that have eroded away portions of the pipe and created significant alluvial deposits of diamonds. These deposits are also actively mined.

Production

The Argyle diamond mine leads the world in volume production of diamond, averaging annual production of 35 million carats (7,000 kg), or about one third of global production of natural diamonds. The Diamonds are hii Production peaked in 1996, when 42 million carats (8,400 kg) were produced. Of this quantity only 5% is considered gem-quality, with the rest being either near-gem quality or industrial grade; this is somewhat below world averages of about 20% of mined diamonds qualifying as gem-grade. Since the mine's opening in 1985, it has produced over 600 million carats (120,000 kg) of diamonds. Meanings of Carat or Karat: Carat (mass) is a unit of mass for gems. ... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ...

Most of Argyle's gem quality production is in brown diamonds. These diamonds are usually difficult to sell, although Rio Tinto has seen some success in a decade-long marketing campaign to promote brown diamonds as champagne and cognac toned. In contrast, the company has no problems selling pink and red diamonds, which are very rare and in high demand, therefore commanding premium prices. The color champagne is a name given for several pale shades of yellow or beige. ... Cognac is a commune in the French département of Charente, of which it is a sous-préfecture. ...

The mine has ore processing and diamond sorting facilities on site. Once diamonds are removed from the ore and acid washed, they are sorted and shipped to Perth for further sorting and sale. A significant quantity of diamonds are cut in India, where low costs of labor allow small diamonds to be cut for a profit; this is especially relevant to the Argyle mine, which on average produces smaller rough diamonds than other mines do.

Diamond characteristics

The diamonds produced at the Argyle diamond mine are of on average low quality. Only 5% of mined diamonds are of gem quality, compared to a worldwide average of 20%; of the remaining 95%, they are about evenly split between classifications of "near gem quality" and industrial grade. 80% of Argyle diamonds are brown, followed by 16% yellow, 2% white, 2% grey, and less than 1% pink and green. Despite the low production volume of pink and red diamonds, the Argyle mine is the only reliable source in the world, producing 90 to 95% of all pink and red diamonds. Most Argyle diamonds are classified as type 1a (see material properties of diamond), and have low levels of nitrogen impurities, their color resulting instead from structural defects of the crystal lattice. Argyle diamonds tend to fluoresce blue or dull green under ultraviolet light, and blue-white under X-ray radiation. The most common inclusion is unconverted graphite, followed by crystalline inclusions of orange garnet, pyroxene, and olivine. This article addresses the material properties of diamond. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized Cadmium selenide (CdSe) quantum dots. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γραφειν: to draw/write, for its use in pencils) is one of the allotropes of carbon. ... The garnet group of minerals show crystals with a habit of rhombic dodecahedrons and trapezohedrons. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... Olivine The mineral olivine is a magnesium iron silicate with the formula (Mg,Fe)2SiO4 in which the ratio of magnesium and iron varies between the two endmembers of the series: forsterite (Mg-rich) and fayalite (Fe-rich). ...

Reserves

Initial proven reserves of the Argyle mine were 61 million metric tons (tonnes) of ore, with an average ore grade or diamond concentration of 6.8 carats (1.36 g) per tonne, about 400 million carats (80,000 kg). Further estimated reserves of 14 million tonnes of ore, at a grade of 6.1 carats (1.22 g) per tonne, 85 million carats (17,000 kg), also existed. As of 2001, reserves and resources in the open-pit mined area contain 220 million tonnes of 2.5 to 3.0 carat (500 to 600 m) per tonne graded ore, sufficient to sustain current production rates until 2007. The ore grades at the Argyle mine are unusually high, with most commercial diamond mines averaging grades of 0.3 to 1.0 carats (60 to 200 mg) per metric ton. Alluvial deposits of diamonds are believed to have been exhausted. A tonne (also called metric ton) is a non-SI unit of mass, accepted for use with SI, defined as: 1 tonne = 103 kg (= 106 g). ... Ore grade is a measure that describes the concentration of a valuable natural material (such as metals or minerals) in its surrounding ore. ... 2001 is a common year starting on Monday of the Gregorian calendar, and also: The International Year of the Volunteer The United Nations Year of Dialogue Among Civilizations Events January January 1 - A black monolith measuring approximately nine feet tall appears in Seattles Magnuson Park, placed by an anonymous...

In 1995, drilling samples taken from about 300 metres below the floor of the pit indicated the possible presence of about 100 million tons of ore, with an estimated grade of 3.7 carats (740 mg) per ton. In 1998, it was decided to instead move mining operations toward the west ridge of the mine, where 64 million tons of ore graded at 2.6 carats (520 mg) per ton are located.

An exploration decline is was constructed at a cost of 70 million Australian dollars to see evaluate the economics of mining diamonds from the diamoniferous pipes below the floor of the open pit; these reserves would be mined underground (via sub-level caving), rather than the open pit method currently used. In late-2005 Rio Tinto Ltd concluded that the operation was economically feasible and pre-production construction of the underground mine is due to commence in early to mid 2006. The Australian dollar (currency code AUD) has been, since 1966, the currency of the Commonwealth of Australia, including the Australian Antarctic Territory, Christmas Island, Cocos (Keeling) Islands, Heard Island and McDonald Islands and Norfolk Island, as well as the independent Pacific Island states of Kiribati, Nauru and Tuvalu. ... For other uses, including the shape â—Š, see Diamond (disambiguation). ...

Economics

The Argyle diamond mine is economically feasible because its large reserves and high grade ore offsets a low average diamond weight value. The estimated value of Argyle diamond production is only 7 USD per carat ($35/g); this compares to values of 70 USD per carat ($350/g) for diamonds produced at the Diavik mine in Canada, and 170 USD per carat ($850/g) at the Ekati mine (also in Canada).[1] However, Argyle has two to four times the concentration of diamonds (ore grade) of these mines. This makes extraction economically feasible, as mine costs are mostly related to the amount of ore processed, not the amount of diamond which is extracted. The United States dollar is the official currency of the United States. ...

History

Small quantities of alluvially deposited diamonds have been known in Australia since the late 19th century, first found by prospecters searching for gold. However, no source volcanic pipe deposit was apparent. A systematic search of Western Australia for the source of these diamonds began in 1969, and on October 2, 1979, the Argyle pipe was discovered. Over the following three years, the deposit was assessed for economic viability, and in 1983 the decision was made to commence mining operations. Alluvial mining operations commenced immediately, while the open pit mine was constructed over a period of 18 months at a cost of 450 million Australian dollars. The mine was commissioned in December 1985. General Name, Symbol, Number gold, Au, 79 Chemical series transition metals Group, Period, Block 11, 6, d Appearance metallic yellow Atomic mass 196. ... October 2 is the 275th day (276th in leap years) of the year in the Gregorian Calendar, with 90 days remaining. ... This page refers to the year 1979. ...

External links

• Argyle Minesite on Infomine
• Argyle Diamonds homepage
• Satellite image of Argyle diamond mine from Google Maps

Several of this article's references contain excellent maps and photographs of the mine and examples of diamonds produced there, which cannot be placed in this article due to copyright limitations. The reader is especially directed to Shigley, Chapman, and Ellison's Gems & Gemology article [2] in this regard. Screenshot of Google Maps showing a route from Toronto to Ottawa Penang island and Seberang Prai on the mainland as seen on Google Maps [1] Google Maps (for a time named Google Local) is a free, web map server application and technology provided by Google that powers many map based... Copyright symbol. ...

References

• Chapman, J. et al. (1996). "The Argyle Mine and Its Diamonds" (adapted from Chapman). Australian Gemmologist 19, pp. 339-346.
• Earth Observatory, NASA (2002). "New Images: Argyle Diamond Mine, Australia". Retrived March 17, 2005.
• Mining-technology.com. "Rio Tinto: Argyle Diamond Mine, Kimberley, Australia". Retrieved March 17, 2005.
• Shigley, James E; Chapman, John; and Ellison, Robyn K. "Discovery and Mining of the Argyle Mine Deposit, Australia". Gems & Gemology: Spring 2001.
• http://www.riotintodiamonds.com. Retrieved March 17, 2005.
• "The Australian Diamond Industry". Retrieved March 17, 2005.
• "Gold and Silver Forum". Retrieved March 22, 2005.