Lithium Brine Resource Estimates for the Salar de Centenario Project

M&A developed drainable and extractable resource estimates for brine aquifers in two basins based on measured aquifer parameters, lithium concentrations, and the effective porosities of the host aquifers. We routinely update the extractable resource estimates using a density-coupled flow-and-transport model as new data become available. We are currently developing strategies for recharging depleted brine to support the facility’s design and operation.

Overview

The mineral-enriched brine aquifers of Centenario and Ratones basins contain potentially commercial quantities of lithium metal. Currently in the prefeasibility phase, this project investigates the use of wells to pump lithium-enriched brine and produce lithium carbonate via proprietary processing methods.

Services

M&A evaluated the mineral resource in accordance with the Canadian Securities Administrators National Instrument (NI) 43-101 Standards of Disclosure for Mineral Projects, applying standards of the Canadian Institute of Mining Best Practice Guidelines for Resource Estimation for Lithium Brines. Daniel Weber, Michael Rosko, and Edward Peacock served as the Qualified Persons for the project.

Brine Resources

  • Conducted diamond drilling programs to collect core samples for lithologic characterization and drainable porosity measurement
  • Developed vertical profiles of specific electrical conductivity, temperature, and density in brine wells
  • Designed pumping tests and analyzed data to estimate hydraulic parameters for brine and freshwater aquifers
  • Designed and coordinated tracer tests to determine transport parameters and flow patterns
  • Developed a conceptual hydrogeologic model using the results of exploration drilling and testing and constructed a database of hydraulic and brine quality parameters
  • Prepared technical reports following NI 43-101 requirements and best-practice guidelines for brine mineral resources

3D Geologic Modeling

  • Developed a 3D geologic model using ARANZ Leapfrog to provide a framework for the resource estimate and numerical flow model

Groundwater Modeling

  • Developed a model using MODFLOW-SURFACT to simulate density-dependent flow and transport within the brine and freshwater aquifers
  • Developed a brine mineral resource estimate and subdivided it into estimated Inferred, Indicated, and Measured categories
  • Used the model to project lithium concentrations according to resource confidence levels and evaluated the feasibility of production-level pumping of brine and freshwater aquifers
  • Evaluated pumping over a life-of-mine period, refining the wellfield layouts to maximize lithium production and minimize drawdown
  • Transitioned the MODFLOW-SURFACT model to FEFLOW to simulate the brine and freshwater wellfields and brine disposal basins

Managed Aquifer Recharge

  • Evaluated hydrogeologic, meteorological, satellite imagery, and other data to characterize discharge alternatives for depleted brine from a proposed processing facility
  • Estimated sustainable recharge rates based on the lithologic conditions and infiltration capacity of salar soils and the vadose zone
  • Estimated brine evaporation rates, prepared a water-balance model to project the potential extents of a brine lake, provided conceptual aquifer recharge options for excess discharge of depleted brine, and worked closely with the client to design options of a depleted brine storage facility