Argyle diamond mine at the Ekati mine, both in Canada. However, Argyle has two to four times the concentration of diamonds (ore grade) of these mines. This makes extraction economically feasible, as mine costs are mostly related to the amount of ore processed, not the amount of diamond extracted. In 2005, Rio Tinto was given the go-ahead to a future expansion project, moving it from an open pit to an underground mine. This plan was postponed; in September 2010 Rio Tinto announced fresh plans to develop an underground mine beneath the existing pit, increasing annual production to 9 million tonnes of ore. The
Hugo Dummett on a "shoestring," staked some promising ground near Lac de Gras in 1989. Dummett took a new job with BHP Minerals in 1989, and convinced his new employer to lease their property. In 1991, BHP drilling on their leased claims found micro-diamonds, sparking one of largest claimstaking rushes in mining history. Under Dummet's direction, BHP eventually developed commercial diamond reserves in five pipes; the discovery pipe turned out to be non-commercial. BHP began the permitting process for the Ekati Diamond Mine in 1995, received final approval in 1997, and opened the mine late in 1998. By 2009, annual sales from