Argyle diamond mine of tunnelling, the Argyle underground block cave development was officially completed. In 2013, Argyle is estimated to produce 10.2 million carats with an average per carat price of $25/carat. The Argyle diamond mine is also notable for being the first successful commercial diamond mine exploiting a volcanic pipe of lamproite, rather than the more usual kimberlite pipe; much earlier attempts to mine diamonds from a lamproite pipe in Arkansas, USA were commercially unsuccessful. The Argyle 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
Merlin diamond mine mines worldwide, and a mere 5% gem-quality production at Australia's largest diamond mine, Argyle diamond mine. The high ratio of gem-quality diamonds is responsible for a relatively high value of $108 USD per carat (540 $/g). The known ore grade at Merlin is about 0.2 carats (40 mg) per tonne, although exploration continues under the mine's new owner. The largest diamond produced at the Merlin mine measured 104.73 carats (20.946 g), the largest ever found in Australia, and has been valued at over $525,000 USD . The mine and mining rights were sold by Rio Tinto Group, to Striker Resources,