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
Orapa diamond mine and Damtshaa diamond mines. Orapa and its sister mine Letlhakane employ over 3,100. Debswana also maintains a 100-bed hospital, pre-primary and primary schools for employees' children, and the Orapa game park. The mine maintains an ISO 14001 certificate for environmental compliance, and places some importance on water conservation and waste management. Orapa diamond mine The Orapa diamond mine is the world's largest diamond mine by area. The mine is located in Orapa, a town in the Central District of Botswana about west of the city of Francistown. Orapa ("resting place for lions") is owned by Debswana, a partnership between the