Diamonds in Australia
PostBy Avi Paz Group At 15.08.2010
The accidental discovery of alluvial diamond deposits in the process of panning for gold that uncovered Brazil's diamond resources repeated itself in Australia. Starting in the latter part of the 19th century, gold prospectors had noted alluvial diamonds, but these stones had no visible nearby source.
Only in 1969 was a serious search for diamond sources undertaken in Western Australia, and a decade passed before the Argyle kimberlite pipe was discovered in October 1979. Once the Argyle project received a green light for development in 1983, alluvial mining began immediately while an open pit mine was built over the next 18 months.
Today, the Argyle Mine – one of only three diamond mines in Australia – produces 35 million carats of rough diamonds a year, making it the world's third-largest single producer of natural rough diamonds, only 5% of which are classified as gem-quality, considerably lower than the average 20%. Nevertheless, Argyle is the world's major source of prized pink and red diamonds, supplying some 90% of all natural pink stones, as well as other fancies, including blue and green diamonds.
The Argyle Mine is also notable as the first diamond project to successfully extract diamonds from a lamproite rather than a kimberlite volcanic pipe.
In contrast to the Argyle Mine, the Merlin Mine in Australia's Northern Territory produced a much higher amount of fine rough diamonds than average during its four years of operation, with 65% of the mine's diamonds classified as gem-quality. The Merlin Mine also produced the largest Australian diamond to date, a 104.73 carat stone valued at over $500,000. The Merlin Mine has been sold and the new owner is pursuing exploration.
In 2002, a third diamond mine, the Ellendale deposit owned by the Kimberley Diamond Company, started production and within a year had produced 50,000 carats of rough diamonds.
Australia was the world's fourth-largest producer of rough diamonds in 2009. The Kimberley Process 2009 Global Annual Summary put the nation's total rough production as 15.6 million carats with a dollar value of close to $313 million.
