The Argyle diamond mine in Western Australia, also known as the diamond industry's greatest source of pink gems, has officially moved from an open-pit operation to an underground operation, Mining Weekly reports. The conversion from the former to the latter cost Argyle owners Rio Tinto a cool $2.2 billion and will ensure that the mine can continue to produce for at least another seven years.

Eight hundred million carats of rough diamonds have been unearthed at Argyle in the last 25 years. Using modern block caving technology, Rio hopes to continue extracting another 20 million carats of rough diamonds annually.



Rio Tinto chief executive officer of diamonds and minerals Alan Davies noted that the mine's move underground will mean its continued contribution to the regional economy of East Kimberley. Argyle managing director Kim Truter noted the significance of the move and expressed gratitude to all of the people who have contributed to the mining operation over the years, according to Mining Weekly.