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
Baken diamond mine 100 cubic metres (3.38 mg/m³). There is a waste rock overburden of about 33 million cubic metres. Baken diamond mine The Baken diamond mine is a diamond mine located along the lower Orange River in South Africa. The mine is owned and operated by Trans Hex. The central processing plant has been operational at Baken since 2001. In 2004 the Baken mine produced ; average stone size for the year was . Notable stones from production in 2004 included a , D colour flawless diamond that sold for over $1.8 million USD; and a pink diamond sold for over $1.0