The Cauchari and Olaroz Salars are classified as “Silver Peak, Nevada” type terrigenous salars. Silver Peak, Nevada in the USA was the first lithium-bearing brine deposit in the world to be exploited. These deposits are characterized by restricted basins within deep structural depressions in-filled with sediments differentiated as inter-bedded units of clays, salt (halite), sands and gravels. In the Cauchari and Olaroz Salars, a lithium-bearing aquifer has developed during arid climatic periods. On the surface, the salars are presently covered by carbonate, borax, sulphate, clay, and sodium chloride facies.

Cauchari and Olaroz have relatively high sulphate contents and therefore both salars can be further classified as “sulphate type brine deposits”.

The brines from Cauchari are saturated in sodium chloride with total dissolved solids (TDS) on the order of 27% (324 to 335 g/L) and an average density of about 1.215 g/cm3. The other primary components of these brines are common to brines in other salars in Argentina, Bolivia, and Chile, and include: potassium, lithium, magnesium, calcium, sulphate, HCO3, and boron as borates and free H3BO3.

A total of 56 wells were used to simulate brine extraction for the Updated Mineral Reserve Estimate. The wells comprising the brine extraction wellfield are spatially distributed in the Resource Evaluation Area of the Project to optimize well performance and capture of brine enriched in lithium. Production was initiated in Year 1 of the pumping schedule representing 23 Phase 1 wells. In Years 2 through 40, 33 wells are added to the pumping schedule for duration of the life of mine plan. During the Phase 2 pumping period, the average nominal pumping rate per well is 16 L/s capacity, providing approximately 903 L/s of lithium enriched brine from the aquifer to the evaporation ponds.

Due to uncertainties in the spatial distribution of aquifer hydraulic properties and ultimate well hydraulic efficiencies at constructed production wells, difference may exist between pumping rates applied in the simulation versus measured pumping after construction of wells. Therefore, estimates of capital and operating costs should include a contingency allowance of additional wells to ensure that production targets can be achieved. In addition, it is likely that wells will need to be rehabilitated or replaced during the 40-ear production period and cost estimates should include provisions to cover such expenditures.

The lithium recovery process consists of the following main processing stages:
- Brine production from wells;
- Sequential solar evaporation;
- Pond-based impurity reduction by liming;
- Plant-based impurity polishing;
- Lithium carbonate precipitation;
- Mother liquor treatment and recycle;
- Lithium carbonate crystal compaction and micronization; and
- Lithium carbonate packaging.

A brine evaporation rate of 6.05 mm/day was used as the design criteria for the pond system.

The pond system consists of 28 evaporation ponds segregated into the following types:
- 16 pre-concentration ponds;
- 6 halite ponds;
- 2 ponds as sylvinite ponds;
- 2 ponds for control; and
- 2 lithium ponds.

Each pond is equipped with a pump station and pipeline system for transferring brine between ponds.

As brine concentrates, the salt precipitates in the pond thus purifiying the brine. Salt that precipitates in the bottom of ponds is porous and entraps brine. In order to recover pond volume taken up by precipitated salt and recover lithium values entrapped with the brine, salt will be harvested. Harvesting will begin after the third year of steady operation.

Harvesting operation consists in draining the free brine from the pond, scraping the salt to a minimum depth, and making drainage piles before removing salt. Draining the entrapped brine from the salt will recover roughly ½ the lithium that was entrapped in the salt. This recovery is not considered in the current process yield estimates presented in this DFS. Harvesting will include 24/7 operations to satisfy overall production plans.

Boron removal is necessary to achieve high-quality lithium product. A solvent extraction stage will allow an effective removal of this element.

Magnesium must be removed before the carbonation step. This is accomplished by adding a combination of lime and soda ash in a set of reactors. The lime reacts with the magnesium in the brine to form insoluble magnesium hydroxide. The precipitated solids will be removed by a solidliquid separation system.

Residual sulfate ions will be precipitated by addition of calcium and barium chloride in a stirred reactor. The precipitated solids will be removed by a solid-liquid separation system.

Residual calcium in the brine will be precipitated with soda ash. The precipitated solids will be removed by a solid-liquid separation system. An ion exchange system will act as a guard to remove any residual calcium, magnesium or other ions with a +2 charge.

Potassium concentrations will be reduced by evaporative crystallization and centrifugation to eliminate sylvinite crystals.

The centrifuges will wash the crystal with condensate to maintain a high yield of lithium, and the wash water will be sent to the evaporator feed.

Mother liquors will be neutralized with HCl and sent to a dedicated pond for concentration to plant head feed Li-concentration levels.

A micronization system will be employed to produce fine lithium carbonate for customers who require a small, narrowly distributed particle size.