Olaroz is managed through the operating company Sales de Jujuy S.A. (SDJ), which is owned 66.5% by Arcadium, 25% by Toyota Tsusho Corporation (TTC) and 8.5% by Jujuy Energia y Mineria Sociedad del Estado (JEMSE).
On March 6, 2025, Rio Tinto completed its acquisition of Arcadium Lithium plc. Rio Tinto is now the ultimate parent company of Arcadium Lithium, which will become Rio Tinto Lithium.
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Summary:
The principal lithium-bearing region of South America is located within the Puna plateau geologic province. In the southern Puna, combinations of east-trending volcanic chains and north-trending, reverse fault–bounded structural blocks comprise several hydrologically closed (endorheic) basins. In the semiarid to hyperarid climate of the Puna, where evaporation rates far exceed precipitation, the hydrologic terminus of an endorheic basin is a dry lakebed, or salar. These are typically flat and expansive with little or no perennial water or vegetation. Surface water drains into these closed basins and evaporation dominates the water balance, leaving behind brines enriched in various metals and salts, sometimes including economic levels of lithium, boron, and/or potassium.
The Olaroz project is a lithium salar deposit, located in a closed basin in the Andean mountain range in northern Argentina.
The sediments within the salar consist of halite, clay, silt, sand and gravel which have accumulated in the salar from terrestrial sedimentation from the sides of the basin. Brine hosting dissolved lithium is present in pore spaces and fractures within unconsolidated sediments.
Evaporation of brines entering and within the salar generates the concentrated lithium that is extracted by pumping out the brine.
The sediments are interpreted to be essentially flat lying with unconfined aquifer conditions close to surface and semi-confined to confined conditions at depth, although faulting on the eastern margin of the salar is likely to control the deposition of sediments and the angle at which they were deposited.
Mineralisation in the Olaroz salar consists of lithium dissolved in a hyper-saline brine, which is about eight times more concentrated than seawater. The natural lithium concentration is the product of solar evaporation of brackish water which flows into the salar as groundwater and occasional surface water flows. The concentrated brine with lithium is distributed throughout the salar in pore spaces between grains of sediment. The brine also extends a considerable distance away from the salar, beneath alluvial gravel fans around the edges of the salar. These areas are largely unexplored by the company to date. In addition to lithium, there are other elements, such as sodium, magnesium, and boron, which constitute impurities that are removed in the ponds and processing plant.
Dimensions
The lateral extent of the resource has been defined by the boundary of brine hosted in unconsolidated sediments, that extends off the salar. In the east and north of the resource area the boundary is with adjacent properties. At ground surface, the brine mineralisation covers 475 km2.
The top of the model coincides with the topography obtained from the Shuttle Radar Topography Mission (SRTM). The original elevations were locally adjusted for each drill hole collar with the most accurate drill hole collar coordinates available from a recent re-survey of the holes.
The top of the brine mineralisation is based on the pre-pumping brine phreatic surface.
The base of the resource is the base of the basin, as interpreted from gravity geophysics. Tertiary sediments are interpreted to underlie the unconsolidated younger salar sediments. These sediments are similar to those of the younger salar sediments, but more consolidated, and can be locally difficult to distinguish.