THE AUSTRALIAN DIAMOND INDUSTRY

Australian Argyle Diamonds are internationally reowned for their unique brilliance and stunning array of colours. Unearthed in the rugged Kimberley region in the far north of Western Australia, Argyle Diamonds thrill in shades of exotic pink, sparkling champagne, rich cognac and dazzling white.  

From the rare pink diamond to the classic white and natural champagnes, Argyle Diamonds are firing the world's imagination. And why shouldn't they? The Argyle Diamond Mine is the world's biggest producer of natural diamonds and contributes approximately one-third of the world's natural supply.

Discovery Of The Argyle Diamond Mine
The Argyle diamond story has its origins in the early 1970s, when one of the world's most significant find of diamonds was made at Smoke Creek in the remote north of Western Australia, over 2000 kilometres from Perth, the state capital.

Although significant, it is certainly not the first discovery of diamonds in Western Australia. Diamonds had been recovered in the Pilbara region as far back as the 1890s but the primary source of any of these diamond finds had never been located.

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The key was time and patience. For decades, geologists had known that a major source of diamonds existed in Australia, but is wasn't until 1972 that their work had identified the Kimberley region as being the most likely location. A joint venture was formed. Geologists spend the next seven years patiently searching the region to discover the Argyle diamond deposit, tantalised by new clues and frustrated by dead ends.

 

The geologists received their biggest encouragement yet with the Ellendale Prospect in 1977. A number of diamond-bearing kimberlite pipes were discovered in Ellendale, located near Derby. However, the evaluation of the Ellendale Prospect showed it to be uneconomical.

It wasn't until October 2 1979, that geologists were literally standing on top of the richest diamond deposit in the world. They had pinpointed the Argyle Diamond pipe.

 

The discovery was made while working in Smoke Creek near the awesome Lake Argyle, a man-made dam covering some 720 square kilometres. Geologists found several stones in the creek bed and back tracked along the course finding more diamonds as they went until they climbed high into the range and before long were standing on the Argyle diamond pipe.

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What followed was an exclusive programme of drilling, sampling and evaluation. In 1982 the joint venture partners decided to develop a mining operation.    

The Argyle Diamond Mine
In 1983, construction work began on the main open-cut mine and process plant. In the meantime, diamonds began to be recovered by an alluvial plant at Smoke Creek and Limestone Creek. Some 15 million carats of alluvial diamonds had been recovered by the time the main Argyle plant was commissioned in 1985.

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Argyle Diamond Production
The Argyle diamond mine has firmly placed Australia on the top as the world's biggest producer of diamonds in terms of volume. As well as being Australia's only major diamond producer, the Argyle diamond mine is also one of the most technologically advanced mines in the world.

Since its inception, annual production has steadily increased from 29 million carats in 1986, the mine's first full year of production, to 40.9 million carats in 1993. The average annual production since 1994 has been over 35 million carats.

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Every year the Argyle diamond mine is responsible for producing more than a third of the world's total annual supply of diamonds. The average annual production now totals over 35 million carats.

The Argyle diamond mine yields approximately 45 per cent near gem quality, and 50 per cent industrial quality diamonds. The remaining 5 per cent is made up of gem quality diamonds and yields the rare and highly valued pink diamonds, as well as the range of sparkling champagne and rich cognac diamonds.

 

Argyle Diamond Mining
The Argyle diamond mine covers an area of 45 hectares. The diamonds are recovered from the main pipe as well as from, to a lesser extent, alluvial deposits in nearby Smoke and Limestone Creeks.

The Argyle diamond pipe is a linear body, 1600 metres along and varying in width from 150 to 600 metres. In addition to being the world's biggest diamond producer and only reliable supply of intense pink diamonds, the Argyle diamond mine is unique in a third way: the diamonds are recovered from a host rock call lamproite, not kimberlite which is the traditional host.

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Argyle's pipe mining operation involves the removal of the diamond-bearing lamproite ore by open-cut mining techniques. The ore is dislodged by blasting and then loaded by excavators into 120-tonne dump trucks. The ore is then transported to the processing plant where the diamonds are extracted. The processing techniques are purely physical and involve crushing, scrubbing, screening and gravity separation of the diamond-bearing ore. Final diamond recovery is achieved by the use of x-ray sorting machines. The machines can detect and remove diamond material because the diamonds fluoresce under x-ray.  

No chemical treatment is included in the process with the exception of a final acid cleaning of the diamonds.

Alluvial mining was discontinued in late 1985, then resumed in 1989. The diamonds recovered are included in the mine's overall annual production.

 

The rough diamonds are transported to Perth for sorting and sale.

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Argyle Diamonds
Argyle Diamonds fall into three main categories: pink, champagne, and white diamonds. The 4C's guide to quality and value applies to coloured diamonds just as it does to white diamonds. However, coloured diamonds are graded for their intensity of colour, not lack of it.

Argyle diamonds have two very unique and outstanding features: they are harder than other diamonds and may fluoresce blue under ultra-violet light.

 
The hardness factor of Argyle diamonds results from its unusual atomic structure. Although all diamonds share the same atomic structure, the atoms of Argyle diamonds are bonded together in more complex arrangements. This complex structure is also one of more the major reasons for the deep colours of the Argyle product mix, especially the champagne and pink diamonds.  

Around 70 per cent of the Argyle yield fluoresces blue under ultra-violet light; a day with high U.V levels will make an Argyle diamond dance and dazzle with lovely blue flashes!

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The huge diamond shipments from the Argyle Mine are sorted at the Western Australian capital of Perth, the headquarters of Argyle Diamonds. The modern cutting and polishing facility is also located here however, only top quality gems from the mine are polished at this facility.

 

Diamond Sorting
Upon reaching Perth, the rough diamonds are sorted. In order to deal with the huge volume of diamonds, Argyle Diamonds has developed new technology. Sorting begins mechanically: the first size sorting of rough diamonds takes place through a series of mechanical sieves.

 

After sieving, the smaller stones are sorted according to colour and shape by sophisticated equipment at the machine sorting area.

However, final valuation of the diamonds can only be made by the human eye despite these advances in technology. Each individual stone is examined by diamond sorters who base their decision on clarity, size, shape and colour. Argyle retains its best quality gems for cutting and polishing.

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Diamond Polishing
Argyle Diamonds carefully selects the best quality diamonds for polishing within Australia or by overseas cutting centres.

Australian Production

Argyle Diamonds began polishing diamonds in 1984. Its Perth processing centre is the first of its kind in Australia.

 

Australian production is staffed by highly-trained crafts-people who employ a combination of traditional methods and modern equipment to unlock the brilliance of rough stones. Argyle uses advanced technology in the form of laser devices, automatic bruting and computerised polishing equipment.

 

The polished stones are then sold in Australia, through a network of exclusive Australian jewellers, as well as overseas through Argyle's representative offices in Antwerp, Belgium and Bombay, India.

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Overseas Production

Argyle Diamonds also sends a proportion of its rough diamonds, especially those in smaller sizes, overseas for polishing.

 

 

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