Summary

Mine Type	In-Situ
Study Completed	Feasibility
Stage	Fully Permitted
Commodities	Lithium Potassium
Mining Method	Brine mining
Mine Life	...
Snapshot	The Maricunga project is a lithium brine development project located on the north side of the Salar de Maricunga in the Atacama Region of northern Chile, part of the “lithium triangle” encompassing parts of Chile, Argentina and Bolivia. The updated Definitive Feasibility Study for the initial stage of the Maricunga Project ("Stage One") was issued in January 2022, based on brine production only from the ‘Old Code’ mining concessions (OCC) (to a depth of 400m) to support production of battery grade lithium carbonate. Environmental Impact Assessment (EIA) for this Stage One project has been approved in February 2020. The Project is now ready to move towards construction subject to completion of Project Financing. The integrated lithium project will be developed and executed in partnership with a strategic partner, whose selection process began in mid-2024 and is expected to be concluded in the second quarter of 2025.
Latest News	Rio Tinto partners with Codelco to develop lithium project in Chile’s Salar de Maricunga     May 19, 2025

Deposit type

• Brine
• Evaporite

Summary:

Salar de Maricunga is a mixed style salar. An upper halite unit occurs (up to 34 m in thickness) in the central northern part of the Salar and hosts the upper brine aquifer. The halite unit is underlain by low permeability lacustrine sediments. The Salar is surrounded by relative coarse grained alluvial and fluvial sediments. These fans demark the perimeter of the actual salar and at depth grade towards the centre of the Salar where they form the distal facies with an increase in sand and silt. At depth two unconsolidated volcanoclastic units have been identified that appear quite similar. These two volcanoclastic units are separated by a relatively thin and continuous sand unit which may be reworked material of the lower volcanoclastic unit. A volcanic breccia was identified on the northern and western parts of the OCC that locally interfingers with the lower volcanoclastic unit. A lower brine aquifer is hosted in the lower alluvial, volcanoclastic, and volcanic breccia units (below the lacustrine sediments).

Mineralization
The brines from Maricunga are solutions nearly saturated in sodium chloride with an average concentration of total dissolved solids (TDS) of 311 g/L. The average density is 1.20 g/cm3. Other components present in the Maricunga brine are: K, Li, Mg, Ca, SO4, HCO3 and B. Elevated values of strontium (mean of 359 mg/L) also have been detected.

Brine quality is evaluated through the relationship of the elements of commercial interest, such as lithium and potassium, with those components that in some respect constitute impurities, such as Mg, Ca and SO4.

The brines from Maricunga have an Mg/Li ratio (6.5) very similar to the Atacama brine (6.4). However, Maricunga has a low sulphate content, which is illustrated by the very low molar ratio (SO4+2B)/(Mg+Ca) that is also influenced by a relatively high calcium content.

This is an advantage as it will reduce lithium losses as lithium sulphate salts in the ponds for the conventional solar evaporation process.

Mining Methods

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Comminution

Crushers and Mills

Processing

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Commodity Production

Operational metrics

Metrics
Annual production capacity	....
Daily brine extraction	....
Brine extraction, LOM	....

Personnel

Job Title	Name	Profile	Ref. Date
.......................	.......................		May 15, 2025
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.......................	.......................		May 15, 2025
.......................	.......................		May 15, 2025
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.......................	.......................		May 15, 2025

Total Workforce	Year
......	2022