Deposit Type
The Salar de Pastos Grandes is classified as a “Silver Peak, Nevada” type, terrigenous salar. Silver Peak, Nevada, USA was the first lithium-bearing brine deposit exploited in the world. These deposits are characteristic of arid zone, restricted basins within deep structural depressions in-filled with inter bedded clays, salt (halite), sands and gravels. In the Salar de Pastos Grandes, a lithium-bearing aquifer developed during arid climatic periods under similar conditions.

Mineralization
Ulexite hosted in Quaternary and modern sediments is common in the eastern side of the salar, close to the road to Sijes. It occurs either as small rounded concretions (“papas") in red clays and brown sands, or as a continuous layer (“barra”). Ulexite and colemanite are observed in the horizons of borates hosted in the Sijes Formation (Late Miocene) outcropping east and south of the Pastos Grandes Salar.

Halite is a common mineral within the Salar Pastos Grandes and is mined by digging pools of 4 meter by 1 meter wide and 1 meter. The pools become filled with brine rich in NaCl. The water evaporates at a rate of 6-8 mm/day, concentrating crystalline halite. Each pool is filled with salt in 5 to 6 months and "harvested" with backhoes or loaders. It is accumulated for dehydration before being shipped in bulk or in large bags.

Mineralization at the Property includes lithium-potassium rich – relatively low magnesium brine as detected throu ........

Brine extraction from the Salar will involve installing and operating a conventional brine production wellfield. The production process starts when brine is extracted from the aquifer beneath the Pastos Grandes Salar, it is then pumped from each well to pre-concentration ponds located near the active wells. From these later ponds brine is pumped to the remaining evaporation ponds and, once concentrated and partially purified, it is sent to the lithium carbonate plant.

Wellfield Layout
Results of the pumping tests for the project indicate that pumping rates of individual brine production wells will be an average of 20 l/s for each well. Therefore, it is planned that an average of 30 production wells will be operative at various flow rates optimized to extract brine from areas of higher lithium grades and higher transmissivity in order to meet the required brine feed rate of 540 l/s, as an average (varying from 480 l/s in Stage 1 to 600 l/s in Stage 2). Seasonal fluctuations in the evaporation rate dictate that the required brine feed rate which will decrease during the winter months and will increase during the summer months. Well completion depths will vary and are still being studied. Brine production wells will be completed with 12-inch diameter stainless steel production casing and equipped with 380 V submersible pumping equipment. Permanent power will be delivered to the wellfield area through a mid-range power line.

The overall wellfield conf ........

- subscription is required.