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
Argyle diamond mine Mine in Zimbabwe. The mine site covers about , stretching in a mostly linear shape about 1600 m (5,200 ft) long and 150 to 600 m (500 to 2,000 ft) wide. The mine is of open pit construction, and reaches about 600 m (1,900 ft) deep at its deepest point. The open cut closed in 2010. An underground block cave mine is currently under development, and is likely to extend Argyle's diamond production until 2018. The Argyle diamond mine is located in the Kimberley region in the far northeast of the Australian state of Western Australia. It is located to