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
Letlhakane diamond mine at a processing plant at its sister mine, Orapa diamond mine, about distant. The Letlhakane mine is also managed from the Orapa mine. In 2015, over 2.1 million tons per year of ore was mined, and over 2.3 million tons was treated, resulting in 583,000 carats of diamond. As of 2017, the Letlhakane Mine ceased open pit operations and completed a plant for the processing of tailings. This is expected to extend the life of the operations at this facility until 2043. Letlhakane diamond mine The Letlhakane diamond mine is a diamond mine located in Botswana about west of the