The term "salar" describes an area covered in salt that is formed by the evaporation of groundwater in hydrographically closed desert basins. The Salar de Atacama is located in a depression from where the subterranean brine cannot escape, which is why an endorheic reservoir is formed, and which is supplied with water by precipitation and melting of snow and glaciers from the Andes. The permission of the competent water supervisory authority on the use of groundwater in the Salar depends on the amount with which the fresh groundwater (aquifer) is filled.
ATACAMA SALT FLATS
The Salar de Atacama, as it is known today, was formed over several thousand years by a continuous process of natural evaporation. The saline brine, a highly concentrated saline solution in the subsoil, was also created by this natural process called the hydrological cycle.
The aqueous phase of the brine evaporates naturally in the peripheral area of the Salar, as well as in the inland lagoons. This saline solution, therefore, a constant part of the hydrological cycle.
DIFFERENCE BETWEEN WATER AND BRINE
Beneath the salt coating of the Salar de Atacama is a large deposit of a saline solution with a water content of approximately 70%, the so-called brine. The percentage of salt is relatively high with 300.000 mg / l with sodium, magnesium, lithium, potassium and boron.
It contains seven to eight times more salt than sea water and is therefore unsuitable as drinking water or for agriculture. Brine contains 200 times more soluble solid substances (TDS) than drinking water and 70 times more than water that can hardly be used for agriculture.
According to the Chilean classification NCh1333, no more than 5000 mg / l of TDS is allowed for agricultural irrigation and, according to NCh409, a maximum of 1500 mg / l of TDS for drinking water. Sea water contains approximately 35000 mg / l of TDS and Atacama brine more than 300.000 mg / l. Hence, it does not resemble water in the traditional sense.
In the Salar de Atacama, we extract brine and put it in pools to concentrate the solution through evaporation, replicating a natural mechanism that already exists. That is, an artificial evaporation process that allows water to be returned to the atmosphere, contributing to the natural hydrological cycle.
HYDROGEOLOGICAL MANAGEMENT OF THE SALT
The importance of water resources, internationally, has been acquiring increasing value for countries and their communities, especially in those close to operations such as mining, where the management of water resources plays a transcendental role in the operation. .
It is important to note that the operation does not lose water, the destination of that water is to evaporate, and that is the reason why the Salar is there. The Salar de Atacama is the product of thousands of years of evaporation.
Despite this, there is a strict control that allows to keep records of the water consumption with which we work in the lithium production, with the aim of demonstrating that the operation does not put at risk the supply of the communities, nor the flora and fauna from the surroundings of the Salar.
This plan consists of a complete environmental control monitoring network, which has a total of 225 official control points. This information is available to the entire community through the “SQM Online” website; whose platform provides parameters and variables from the measurement points that we had from the nucleus to the areas surrounding the Salar de Atacama.
Every six months, reports are generated on the behavior of the wells, and the monitoring results are sent to the Superintendency of the Environment (SMA). Most of these control points are in the transition zone, where the lagoons, vegetation and the ecosystem in general are located.