In Bolivia's western highlands, at an altitude of some 3,600 metres, lie the largest identified reserves of lithium in the world. According to the latest estimates by the United States Geological Survey (USGS), beneath the 10,000 square kilometres of what are the world's most extensive salt flats, the Salar de Uyuni, there are some 6 to 9 million tonnes of lithium (Roskill 2008 nach Angerer, Marscheider-Weidemann, Wendl et al. 2009, Jaskula 2010a). Exploitation of those reserves has not yet begun, though the Bolivian government has constructed a small 6 million US Dollar pilot plant on the edge of the Salar de Uyuni, and has some ambitious plans.