Chilean reserves are estimated at around seven million tonnes on the basis of a mine which covers nearly 1,000 km² and available analyses to a depth of 40 metres (K. Evans, 2008). As the analyses in Table 2 show, one of the clear advantages of several Chilean brines is their relatively high Lithium content (up to 1,800 mg/l), but above all their very weak Magnesium/Lithium (Mg/Li) ratio which means that there is no need to eliminate great amounts of magnesium from the brine in advance. In comparison, the brines in the Salar de Uyuni have an Mg/Li ratio which is more than 20 times higher, not to mention production conditions at a much higher altitude and the disadvantages linked to an already very deficient access infrastructure.

Another non-negligible element is linked to climatic conditions as seasonal flooding in the Salar can paralyse the extraction operations, while reduced aridity means that the natural evaporation of the brines is much less effective. According to some data, evaporation in Uyuni is considered to be half that of Atacama, at around 1,500mm/year. According to Maire (2010) production costs of 100 in Atacama are equivalent to 150 in Uyuni and 250 in the hard rock mines of the USA.

A big challenge or "lithium compensation"

The national Bolivian project to promote the Uyuni brines involves three stages: 1) geological exploration; 2) industrial production of lithium carbonate and potassium chloride; 3) production of Li-ion batteries.

The first phase was planned for 2008-2011 and should have ended with the establishment of a pilot brine concentration factory with a symbolic capacity of 40 t/month of Li2CO3 (lithium carbonates) and 1,000 t/month of KC1 (potassium chloride).

Reconnaissance surveys were conducted using a 5km x 5km mesh, while surveys of the potentially richest zone situated in the south-east at the opening of the Rio Grande used a tighter 2km x 2km mesh. The wells were generally very superficial (1m) but some 30m holes were made and more were planned to better evaluate permeability and the sequence of salt crusts. To date, more than 7,000 samples have been analysed and a more precise cartography of the reserves should be available, although this has not yet been officially published.

The Bolivian authorities place a great deal of hope in a national patent on concentration of the brines which could lead to industrial production of 700,000 t of KC1 and 30,000 t of Li2CO3 per year. However, the road ahead is still long and full of pitfalls. As Henri Maire said, it is to be hoped that the lithium mines do not face the same misfortune as the former nitrate mines which were abandoned from one day to the next when alternative fertilisers were found. Although various lithium salts appear likely to be the most highly performing cathode formations for batteries of the future, the industry will never be safe from technological discoveries which could brutally change the lithium industry.

Moreover, without denying that Bolivia has the right to promote its resources to enable the poorest to finally access a more acceptable standard of living, it has to be recognised that the salt lakes in South Lipez are among the most fascinating and fragile ecosystems in the world. Protecting them is a major challenge not only for tourism but also for the geodiversity of our planet. It is certainly possible to reconcile mining and the environment, but only if we are aware of the challenges from the very onset of the project.

It is unacceptable to the Bolivian authorities that the lithium-rich salars remain undeveloped, but the question certainly merits being asked, in exchange for fair financial compensation from the international community.

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