Sal de Vida (Stage 1) is a lithium brine project that is 100% owned by Rio Tinto. The project is operated through Sal de Vida S.A. (SdV S.A.), Rio Tinto’s Argentine subsidiary, which owns and runs the lithium brine production facilities and associated chemical processing plants located in the Eastern Subbasin of the Salar del Hombre Muerto (SdHM).
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Summary:
Sal de Vida is located in the Eastern Subbasin of Salar del Hombre Muerto (SdHM). Immature salars are dominated by clastic deposits with interbedded evaporites. In the Eastern Subbasin, a transition of evaporite facies is observed from basin margins to basin centres, proceeding from sulphates at margins through borates in basin centres.
The lateral boundary of the evaporite sedimentary deposits of the Eastern Subbasin of the SdHM is irregular in shape. From north to south, the Eastern Subbasin is approximately 12 km, where an apron of erosional volcaniclastic sediments surrounding Cerro Ratones, and a large alluvial fan formed by the Rio Los Patos bound the Eastern Subbasin to the north and south, respectively. Roughly 14 km separate the eastern and western margins of the Eastern Subbasin. The eastern margin is characterised by a sequence of preCambrian rocks that form the north-south trending Sierra de Cienaga Redonda. The western margin opens to the Western Subbasin at a shallow bedrock saddle that separates both subbasins where the distance at surface between Farallon Catal and Peninsula Hombre Muerto narrows. The eastern and western subbasins are hydraulically connected at the buried bedrock saddle, where brine and water flow from east to west.
The vertical extent (depth) of the lithium-rich brine deposit, inferred from surface geophysical surveys and drilling, is nominally 350 m. Based on geophysical surveys, lithologic logging, and surface geologic mapping, the bedrock contact is likely greater than 300 m in most of the Eastern Subbasin and may exceed 500 m in the southwest quadrant of the subbasin. Brackish water overlies brine across most of the Eastern Subbasin with a thicker transition zone in the south where groundwater inflows from the Rio Los Patos. The lithium-rich brine targeted for extraction tends to occur from 60 to 80 m bgs, downward to the bedrock contact.
Salar aquifers host lithium-rich brine in the pore space between sediment grains and in primary or secondary fractures. Owing to the depositional environment present at the time the aquifers were formed, these aquifers consist of horizontal to sub-horizontal clastic sediments and evaporites. The package of sedimentary and evaporitic aquifers that host lithium brine beneath the salar surface are collectively referred to as the brine reservoir.
The interconnected nature of pores and fractures governs the ability of brine to drain from the reservoir in response to pumping and is a key factor for assessing the recovery potential of lithium from brine.
The reservoir at SdV consists of 5 major hydrolithologic units: (1) clay, (2) evaporites, (3) silts and sands, (4) sands and silts, and (5) volcaniclastics (travertines, tuffs, and dacitic gravels). Brine production will target units 2, 3, and 4, where hydraulic properties are most favourable, and drainable porosities averaged 4.1, 4.9, and 13.1 percent, respectively.
Water enters the salar from both streams and groundwater discharges from basin-bounding alluvial fans (and potentially from adjacent rock formations). In the broader SdHM watershed, the dominant surface water inflow is via Rio Los Patos, in the Eastern Subbasin. At times of high flow, surface waters accumulate on the salar in the Laguna Catal, which at times can extend into the eastern portion of the Western Subbasin. Water inflows from infiltration of precipitation on the salar surface are negligible. Annual average precipitation rates are less than 90 mm.
Sal de Vida’s brine chemistry has a high lithium grade, low levels of magnesium, calcium and boron impurities and readily upgrades to battery grade lithium carbonate. Long-term hydrological pump testing under operating conditions has demonstrated excellent brine extraction rates to support the production design basis.