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
Dominion Diamond Mines Ekati combined are estimated to produce over 7 million carats of diamonds in 2014, worth an estimated $1.1 billion. Diavik and Ekati are currently ranked the 9th and 19th largest diamond mines in the world, respectively, according to total carat production. The company's participation in the retail segment of the diamond pipeline was by means of its ownership of Harry Winston, Inc., a chain of retail stores. On January 14, 2013 the company announced that it has entered into an agreement to sell its luxury brand diamond jewelry and timepiece division, Harry Winston Inc., to The Swatch Group Ltd. for