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
Jericho Diamond Mine On July 19, 2010 Shear Diamonds (née Shear Minerals Ltd) (), a diamond exploration company focused on the Nunavut region, announced its purchase of the Jericho Diamond Mine. In late 2010, Shear announced that it would take about a year to devise a plan to reopen the mine. Shear began processing the existing recovery reject pile in early 2012, selling the recovered stones to Belgian diamond firm Taché, which provided a revolving line of credit. However, operations were suspended in September, as Shear, citing "limited funds and significant operations", has sought to minimize expenditures. Taché has given notice of default