The salina or salt lake of Surire contains reserves estimated at about 1.500 million metric tons of ulexite, representing 30 million metric tons of B203. Other salts present include calcium carbonate, sodium, magnesium and potassium, sulphates and borates. The lake is tectonic in origin, modified by the accumulations of lava and sediments from the late Quaternary period as well as more recent activities. With the passage of time, the tectonic depression gradually filled with clastic or detrital sediments at the lowest level, chemical sediments in the intermediate layers, and evapories, or saline precipitates, at the upper level. The formation of evaporites was possible because of the climatic conditions which affected the altiplano (high plateau).These fluctuated between total aridity and abundant precipitation. During the pluvial period the dry lake was converted into a swamp which means that the characteristics of its surface structure are quite different from most dry lakes. Research carried out on the deposits and the interpretation of chemical analysis have shown that the evaporites contain a significant concentration of borates and ulexite.The actual mining of these deposits is facilitated by the fact that the minerals that are economically attractive are found in the upper layers of the basin.