Argyle diamond mine
| Argyle open-cast diamond mine | |||
|---|---|---|---|
| General information about the mine | |||
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| Mining technology | Open pit | ||
| Funding / year | 2.8 (2016) t | ||
| Funding / total | 160 tons of diamond | ||
| Information about the mining company | |||
| Operating company | Rio Tinto | ||
| Start of operation | 1983 | ||
| Funded raw materials | |||
| Degradation of | Diamonds | ||
| Diamonds | |||
| AK1 | |||
| Raw material content | 0.0001% | ||
| Geographical location | |||
| Coordinates | 16 ° 42 '44 " S , 128 ° 23' 51" E | ||
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| Location | Kununurra | ||
| State | Western Australia | ||
| Country | Australia | ||
The Argyle diamond mine ( English Argyle diamond mine or Argyle mine ) is an open- cast diamond mine in Western Australia . It is located in a remote area in the east of the Kimberley , about 2,000 kilometers from Perth .
The opencast mine is - with around a fifth of world production - the largest diamond producer in the world . According to Rio Tinto 670 million carats worth 6 billion have been in Argyle US dollar encouraged.
Argyle is one of two operating diamond mines in Australia.
Diamonds
Since the Argyle diamond mine only extracts a small amount of diamonds that are suitable for gemstone production, the mine is not the largest in terms of its added value. It is the diamond mine that extracts 90% of the world's pink diamonds. There are also large quantities of naturally colored diamonds in the colors champagne, cognac and the rare blue. The colors champagne and cognac denote light brown diamonds. The diamond mine, which was previously open-cast , is currently being converted to underground mining, which is scheduled to begin in 2013.
The Argyle Diamond Mine is also known for being the first Lamproit volcanic vent diamond mine to operate economically, which is unusual. Because most diamonds are found in kimberlite chimneys. Diamond mining that used to take place in the Lamproit area, such as the Crater of Diamonds State Park in Arkansas , USA , was uneconomical.
The Argyle mine was part of a joint venture between Rio Tinto (56.8%), Ashton Mining Ltd. (38.2%) and Western Australian Diamond Trust (5%). The Argyle diamond mine is now wholly owned by the Rio Tinto Group , a mining company that also operates the Diavik diamond mine in Canada and the Murowa diamond mine in Zimbabwe . Rio Tinto is the third largest producer of rough diamonds with a share of 20% of world production.
description
The mine extends over an area of 450 km², which is almost linear in a length of 1,600 meters and a width of 150 by 600 meters. In the open pit, the mine reaches its deepest point at around 600 meters; this type of reduction will no longer be used in 2010.
Subterranean mining is being prepared and diamond mining is planned to continue into 2018, according to more recent information from Rio Tinto through 2019.
location
The Argyle Mine is located in the Kimberley region in the far northeast of Western Australia, southwest of Lake Argyle in the Matsu Ranges . The mine is approximately 550 km southwest of Darwin and approximately 185 km from the nearest settlement, Kununurra . Most of the 520 workers come from Perth , which is over 2,000 km away, and work in the mine every two weeks. In the first few years they were flown in to the mine by air. The mine also employs local residents and a large number of Aborigines . The Argyle Mine employs 25% full-time Aboriginal people and 50% live there.
About 20 kilometers away was the Ellendale Diamond Mine , which operated on the southern end of Argyle Lake on alluvial land from 1998 to 2005.
geology
The mine is the first commercially operated diamond mine that does not extract diamonds from a kimberlite slot. Diamonds are also found in alluvial soils . The vent has been named "AK-1" although it is commonly called the Argyle Pipe in Australia .
Inside the volcano chimney is olivine -lamproitisches rock , especially Tuff and solidified lava . The surrounding volcanic facies suggests a lamproic eruption that created a maar . At the borders of the volcanic vent , Lamproit is interspersed with volcanic breccia as shattered rock fragments, mixed in and ground up by the explosion. Minerals of the marginal facies are zeolite , mica , kaolinite and clay , which are typical signs of hydrothermal mixing after a volcanic eruption .
Diamonds have been found in the intact rim of the volcanic vent as well as in some marginal breccia and maize facies. However, some diamonds were cooled in the chimney during the post-volcanic eruption and turned into graphite .
The volcanic vent was formed by an explosive eruption of lamproitic magma in a weak zone of the continental crust.
The diamonds found in the Argyle vent are 1.58 billion years old, while the volcano that created the vent was active between 1.1 and 1.2 billion years. These data indicate a relatively short period of about 400 million years during which the diamond formation was formed, which created diamonds of a small average size and with the unusual physical character of the Argyle diamonds. The diamonds found in the Argyle vent are predominantly eclogitic . This means that the carbon they were made from was of organic origin.
In connection with the vent, there were numerous volcanic outflows that eroded parts of the vent and created alluvial soils in which diamonds were stored. They were also actively degraded in these soils.
advancement
The open pit holds the top position on earth in terms of the volume of diamonds extracted per year with an average of 35 million carats (7,000 kg), which corresponds to around a third of the world production of natural diamonds. The peak value was reached in 1994 with 42 million carats (8,400 kg) mined. Only 5% of these recovered quantities are suitable for jewelry production, the rest is “close to jewelry quality” or they are suitable for industrial purposes. This value is slightly below the usual average of around 20%. (The "near jewelry quality" rating is subjective and misleading, as these diamonds can be cut into jewelry if so decided.) Since mining began in 1983, the diamond mine has produced over 750,000,000 carats (150,000 kg) of rough diamonds.
Most of the diamonds in the Argyle mine are brown, and they are usually difficult to sell, although Rio Tinto has had some success with a lengthy marketing campaign for their brown and champagne colored diamonds. In contrast, there are no sales problems with the diamonds in pink, purple and red hues, which are very rare, are in high demand and are achievable for the top prices. The pink diamonds are processed, polished and sold to customers worldwide by a special team based in Perth . In Kununurra there is a shop run by a German who mainly sells red and pink diamonds; the most expensive at over A $ 600,000.
The mine works with rock and diamond sorting systems in the mining area. First, the diamonds are freed from the rock and washed with acid, sorted and shipped to Perth, where they are further sorted and sold. Some of the diamonds are cut in India, where the low labor costs allow even small diamonds to be cut at a profit. This is of great importance to Argyle, as it produces on average smaller diamonds than in other diamond mines.
Characteristics of diamonds
The diamonds in the Argyle mine are of poor quality on average. Only 5% of the mined diamonds achieve jewelry quality; In a global comparison it is 20%, the remaining 95% are divided into almost jewelry quality and industrial diamonds . 80% of the Argyl diamonds are brown, 16% yellow, 2% white, 2% gray, 1% pink and green. While the Argyle mine is the only consistent resource for red diamonds, it only produced 90% to 95% of all pink and red diamonds. Most Argyle diamonds are classified as Type 1A and have a low content of nitrogen impurities , the colors of which result from a defect in the crystal structure . Argyle diamonds tend to be blue or dull green when fluorescent under ultraviolet light and blue-white under X-rays . The most common inclusions in diamonds are graphite , followed by crystalline inclusions of orange garnet , pyroxene and olivine .
Diamond offer
A small collection of pink diamonds has been sold every year since 1985; this offer is called the Argyle Pink Diamond Tender . For every 1,000,000 carat (200 kg) raw diamonds mined, only one carat (0.2 grams) of pink-colored polished diamonds is for sale.
In March 2009, Argyle first offered the rare blue diamonds. The so-called “Once in a Blue Moon” collection was launched in different years and contained blue and purple diamonds with a volume of 287 carats (57 g).
Deposit
The initially proven reserves of the Argyle Mine were 61 million tonnes (t) of diamond-bearing rock, averaging 6.8 carats (1.36 g ) diamond per t; a total of about 400 million carats (80,000 kg). In addition, there are resources of 14 million t of rock with 6.1 carats (1.22 g) per t (85 million carats, 17,000 kg). In 2001 the reserves of the open pit amounted to 220 million t with 2.5 to 3.0 carats (0.5 to 0.6 g) per ton of rock, sufficient for production up to 2007. The diamond content in Argyle is unusually high Most diamond mines have an average grade of 0.3 to 1.0 carats (0.06 to 0.2 g) per ton. The diamond deposits in the alluvial soils are now considered to be exhausted.
In 1995, a 300 meter deep test well was drilled on the floor of the open pit mine, which resulted in a volume of an estimated 100 million tons of rock with a grade of 3.7 carats per t (0.74 g). The so-called West Wall contained 25 million tons of barren rock and threatened to collapse in the 1990s. In 1998 it was decided to remove or cut off the unstable part in order to develop further diamond-bearing rock in the southern part of the open pit.
The exploration costs to verify the economic production of the diamonds in the volcanic vent below the open pit have been set at AUD 70 million (Australian dollars). The dismantling is to be carried out using the block construction method. In late 2005, Rio Tinto Ltd. decided that the underground mining can be carried out economically and began with the first preparatory measures before the middle of 2006.
economics
The estimated value of the Argyle diamonds is only US $ 7 per carat (US $ 35 / g); while the value of the Diavik Diamond Mine is US $ 70 per carat (US $ 350 / g) and the Ekati Diamond Mine is US $ 170 per carat (US $ 850 / g), both in Canada. However, Argyle has two to four times the diamond content per ton of rock. This reduces the prime costs per carat.
Underground mining
In 2005 Rio Tinto commissioned the development of a future expansion project to continue underground mining. The project was postponed until September 2010 when Rio Tinto announced a new plan for underground mining that would produce 9 million tons of rock annually.
The mine is expected to extract diamonds by 2018 and use the latest technology, including automated mining with Sandvik machines. The dismantling should begin in 2013, two years later than planned.
The underground mining requires considerable technical effort, such as ventilation and drainage .
history
Small amounts of diamonds stored in alluvial areas had been known in Australia since the 19th century, the first being found by prospectors searching for gold. However, no diamond deposits in volcanic vents were known. A systematic search for this source began in Western Australia in 1969. The Tanganyika Holdings had Maureen Muggeridge tasked and trained with her Ashton joint venture after 1976 minerals have been found, which indicated a presence of diamonds. In 1979, Muggeridge discovered diamonds in a sample from a floodplain near a small stream that flowed into Lake Argyle . Soon after, the source of the diamonds was found in upper Smoke Creek . The Argyle chimney was discovered on October 2, 1979.
In the following three years the deposit was examined for economic feasibility and in 1993 the decision to mine it was made. Alluvial diamond mining began immediately while the open pit was built over a period of 18 months at a cost of AUD 450 million and began in December 1985.
Web links
- THE AUSTRALIAN DIAMOND INDUSTRY ( Memento from February 22, 2014 in the Internet Archive ): Images of Argyle diamonds
- riotintidiamonds.com : Rio Tinto Diamonds website
Individual evidence
- ↑ argylediamonds.au ( Memento of September 30, 2009 in the Internet Archive ) (PDF; 1.2 MB): James E. Shigley, John Chapman, Robyn K. Ellison: Discovery and Ming of the Argyle Diamond Deposit . Retrieved January 30, 2012
- ↑ dividendyields.org : The Most Promising Diamond Dividends , January 9, 2012. Retrieved January 30, 2012
- ↑ Diamonds Annual Review 2008 (PDF; 1.8 MB) Archived from the original on July 24, 2011. Info: The archive link was automatically inserted and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved October 22, 2009.
- ↑ mining-technology.com . Argyle Diamond Mine, Kimberly, Australia . Retrieved January 30, 2012
- ↑ a b c infomine.com : More block cave diamonds . Retrieved January 30, 2012
- ↑ Janine P. Roberts: Glitter & greed: the secret world of the diamond empire . Ed .: The Disinformation Company. 2003, ISBN 978-0-9713942-9-2 , pp. 243 ( google.com [accessed February 7, 2017]).
- ↑ http://www.ndr.de/fernsehen/sendung/laender-menschen-ablebnis/lma827.html ( Memento from May 23, 2014 in the Internet Archive )
- ↑ The Argyle Pink Diamonds Tender. (No longer available online.) Archived from the original on May 12, 2009 ; Retrieved October 24, 2009 .
- ↑ Rio Tinto's Blue Diamond Tender Exceeds Expectations. Retrieved October 22, 2009 .
- ^ The New Diamond Age. GIM - Gold and Silver Forum . Retrieved January 30, 2012 ( Memento February 17, 2007 in the Internet Archive )
- ↑ Rio Tinto project expansions roll on with diamonds . In: Reuters , September 14, 2010. Retrieved July 14, 2011.
- ↑ a b Geologist left no stone unturned in quest for glittering prize . In: The Sydney Morning Herald , Fairfax Media, November 26, 2010. Retrieved July 14, 2011.
