Announcement PDF ASX ANNOUNCEMENT 19 December 2023 Maiden Ore Reserve Defined Lake Resources Flagship Kachi Project Lake Resources N.L. (ASX: LKE; OTC: LLKKF) (“Lake” or the “Company”) is pleased to announce its maiden Ore Reserve statement for the Kachi lithium brine project (“Kachi” or the “Project”) in Argentina. The basis for this Ore Reserve statement is hydrogeologic modelling completed for the Project that incorporates the recent Mineral Resource Estimate 1 and extensive hydrogeological characterisation work completed in 2022 and 2023 including extraction and injection testing 2. This Ore Reserve is the basis for the Kachi Project Phase One Definitive Feasibility Study (“DFS”), which was released today. The Ore Reserve demonstrates that the mine plan is capable of delivering sufficient lithium brine to the plant for a planned 25 ktpa operation over the Life of Mine (“LoM”). Ore Reserve demonstrates mine plan capable of delivering sufficient lithium brine for planned 25 ktpa operation: • Mine plan includes 16 production wells and 21 injection wells with average grades and flow rates that exceed production requirements for a 25 ktpa 3 operation for a 25-year LoM. • Ore Reserve is constrained by currently planned plant capacity of 25,228 tpa, not pumping and injection capacities. • Kachi well field layout optimized using the Hydrogeologic Model to maximize lithium grade recovered, maximize Proved Ore Reserve and minimize environmental impacts. • Average lithium feed grade to the plant for the first seven years of operations is 257 mg/L, averages 245 mg/L in years eight to 25 and reduces to 232 mg/L by year 25. • More than 85% of the 25-year Life-of-Mine (“LoM”) production is derived from Measured Resources with the remained predicted to be sourced for Indicated Resources. "We are excited to share the well field development plan and hydrogeologic modeling results for the Project. The modeling demonstrates that the feed grade will average above 245 mg/L with minimal dilution and that the operation can be developed in an environmentally responsible manner," Michael Gabora, Director of Geology and Hydrogeology said. He continued, "The Ore Reserve for the 25 ktpa operation extracts just a small percentage of the Mineral Resource Estimate." 1 See LKE ASX Announcement dated 22 November 2023 2 See LKE ASX Announcement dated 16 August 2023 3 Abbreviations summary: Tonnes per annum (tpa), Million Tonnes (Mt), Lithium Carbonate Equivalent (LCE), meters (m), square kilometers (km2), milligrams per liter (mg/L), Life-of-Mine (LoM) Other Highlights • Reducing the simulated LCE production to the expected plant throughput results in a Proved and Probable Ore Reserve of 624,400 tonnes LCE (see Table 1). The mine plan produces 806,300 tonnes LCE, representing less than 12% of the Measured and Indicated Mineral Resource 4. • The Proved Ore Reserve derived from Measured Resources is constrained to the first seven years of operation, equalling 170,300 tonnes. • Ore Reserves from Measured Resources in years eight to 25 are conservatively categorised as Probable Ore Reserves with the aspiration that these will convert to Proved Reserves as the predictive reliability of the hydrogeologic model increases with additional data collection. • The defined injection strategy maintains higher reservoir pressures and minimises potential environmental impacts. • Dilution in lithium grade is predicted to be <2% in year seven and about 10% in year 25. This principally occurs because of capturing slightly lower grade brine and dilution from spent brine injection. • The hydrogeologic model reproduces historical data very well, which improves the predictive reliability of the model simulations related to lithium recovery and injection. “All the Ore Reserve for the first seven years of operations is in the Proved Ore Reserve category which demonstrates the high level of confidence in the data and modelling work completed to date. More than 90% of the lithium brine continues to be derived from the Measured Resource through the LoM, but the Competent Person (“CP”) has allocated this to the Probable Ore Reserve category. Continued data collection and model updates will most likely result in further upgrades to the Proved Ore Reserve, given the favourable conditions,” Mr. Gabora said. A variable density groundwater flow and solute transport model (“Hydrogeologic Model”) was developed using the Groundwater Vistas interface and MODFLOW-USG 5 code to evaluate the extraction of lithium enriched brine and injection of spent brine after direct lithium extraction (“DLE”) from the wells during the 25-year LoM. The Hydrogeologic Model was constructed based on the geologic framework model developed for the Mineral Resource estimate4. The Hydrogeologic Model incorporates the water balance studies 6, local scale evapotranspiration studies 7, and hydraulic testing work 8. To demonstrate the model's ability to reproduce measured conditions in the basin, it was calibrated to historical observations of lake stage at the “laguna” from 2000 to 2023, evapotranspiration fluxes determined from studies, historical groundwater and brine levels, changes in brine levels during extraction and injection testing, lithium concentrations during extraction tests, and to a lesser extent, the total dissolved solids concentrations. 4 See LKE ASX Announcement dated 22 November 2023 Panday, S. 2023. MODFLOW-USG-Transport (v2.2.1). GSI. Available at: http:// http://www.gsi-net.com/en/software/freesoftware/USG-Transport.html 5 Lithium Solutions, 2023. Hydrophysical Water Budget Assessment and Hydrogeochemical and Isotopic Tracing of Water Source and Transit in Carachi Pampa Basin, Argentina 6 7 Atacama Water, 2022. Kachi Project - Soil evaporation measurements, wet season 2022. April 2022 8 See LKE ASX Announcement dated 16 August 2023 2 The Ore Reserve estimate considers the Modifying Factors of converting Mineral Resources to Ore Reserves, including the production and injection well field designs and efficiency (e.g., location, drilling and well construction details, pumping requirements, etc.), environmental considerations (e.g., changes at key environmental receptors), lithium recovery rates, and plant capacity and is based on the same material assumptions as the DFS. The mine plan produces well field flow rates and concentrations in excess of plant requirements, which provides an additional factor-of-safety that the production schedule can be achieved, even if small changes in ramp-up and ramp-down schedules are implemented. As a result, plant capacity is the limiting factor for the Ore Reserve based on the mine plan presented in this announcement. The Ore Reserve was classified into Proved Ore Reserves and Probable Ore Reserves based on industry standards 9 for lithium brine projects, the CP’s experience, and the confidence in the quality and quantity of both data and hydrogeologic model performance. A majority of the extracted mass is sourced from Measured Resources; nonetheless, Proved Ore Reserves were specified by the CP for the first seven years, given the level of model calibration and yearly production goals (see Table 1). Probable Ore Reserves were conservatively assigned for the last 18 years of the LoM, considering that the model will be continually improved and recalibrated in the future, including additional extraction and injection testing, initial operations, and measurements of dilution, among other factors. Lake has discussed the potential for future Project Phases that would see a further increase in the production, but these phases are not included in this Ore Reserve Statement. The Project well field development plan consists of 16 extraction wells and 21 injection wells in the configuration shown in Figure 1. The Phase 1a wells will be drilled and operated for six months, after which Phase 1b wells will be online. The final two injection and extraction wells (back-up wells) will be online by the start of year two. The extraction is focused on the core of the salar where lithium concentration has been consistently high, and three long-term pumping tests (12 to 31-days in length). Injection wells are located in the coarse-grained alluvial fan materials in the west and along the eastern margin of the central resource area. The injection configuration provides pressure maintenance in the production horizon and near springs along the western margin of the volcano, while keeping dilution resulting from spent brine injection to a minimum. 9 Association of Mining and Exploration Companies, 2020. Guidelines for Resource and Reserve Estimation for Brines. https://www.jorc.org/docs/Brine_Guideline_final.pdf 3 Table 1. Proved and Probable Lithium Reserves Reserve Category Years Lithium (Tonnes) (Tonnes) LCE Average Lithium Proved 1 3,600 18,900 258.6 Proved 2-7 28,500 151,400 257.2 Probable 8-25 85,400 454,100 245.0 Total 1-25 117,400 624,400 (mg/L) Notes to the Ore Reserve Estimate: • Lithium is converted to lithium carbonate (Li2CO3) equivalent with a conversion factor of 5.32. • The effective date for the Ore Reserve Estimate is based on the resource update from November 22, 2023 10. • The Ore Reserves are estimated based on the output from the processing circuit, as the 75% processing efficiency is accounted for in the Ore Reserve estimates. • Numbers may not add due to rounding effects. • Projected processing is based on first year rate of 18,921 tonnes LCE. • Projected processing for years two to 25 rate of 25,228 tonnes LCE. • The CP for the Ore Reserve estimate is Andrew Fulton. 10 See LKE ASX Announcement dated 22 November 2023 4 Figure 1. Modelled well field layout for extraction and injection wells 5 Mr. Gabora said the maiden Ore Reserve statement demonstrates some of the great advantages of DLE and injection of spent brine. “The impacts to the hydrogeologic system are vastly reduced over traditional processing methods as a result of returning the spent brine back into the hydrogeologic system. This effectively maintains pressures in the system, providing both operational and environmental benefits.” Summaries of the Project Background, Mineral Resource and Ore Reserve analysis are provided in subsequent sections. Lake Investors please contact: Global IR: Karen Greene, SVP, Investor Relations, Lake Resources: karen.greene@lakeresources.com.au For media queries, please contact: Nigel Kassulke at Teneo M: +61407904874 E: Nigel.Kassulke@teneo.com About Lake Resources NL (ASX:LKE OTC:LLKKF) Lake Resources NL (ASX:LKE, OTC: LLKKF) is a responsible lithium developer utilising state-of-the-art ion exchange extraction technology for production of sustainable, high purity lithium from its flagship Kachi Project in Catamarca Province within the Lithium Triangle in Argentina. Lake also has three additional early-stage projects in this region. This ion exchange extraction technology delivers a solution for two rising demands – high purity battery materials to avoid performance issues, and more sustainable, responsibly sourced materials with low carbon footprint and significant ESG benefits. Forward Looking Statements: Certain statements contained in this announcement, including information as to the future financial performance of the projects, are forward-looking statements. Such forward-looking statements are necessarily based upon a number of estimates and assumptions that, while considered reasonable by Lake Resources N.L. are inherently subject to significant technical, business, economic, competitive, political and social uncertainties and contingencies; involve known and unknown risks and uncertainties and other factors that could cause actual events or results to differ materially from estimated or anticipated events or results, expressed or implied, reflected in such forward-looking statements; and may include, among other things, statements regarding targets, estimates and assumptions in respect of production and prices, operating costs and results, capital expenditures, reserves and resources and anticipated flow rates, and are or may be based on assumptions and estimates related to future technical, economic, market, political, social and other conditions and affected by the risk of further changes in government regulations, policies or legislation and that further funding may be required, but unavailable, for the ongoing development of Lake’s projects. 6 Lake Resources N.L. disclaims any intent or obligation to update any forward-looking statements, whether as a result of new information, future events or results or otherwise. The words “believe”, “expect”, “anticipate”, “indicate”, “contemplate”, “target”, “plan”, “intends”, “continue”, “budget”, “estimate”, “may”, “will”, “schedule” and similar expressions identify forward-looking statements. All forward-looking statements made in this announcement are qualified by the foregoing cautionary statements. Investors are cautioned that forward-looking statements are not guarantees of future performance and accordingly investors are cautioned not to put undue reliance on forward-looking statements due to the inherent uncertainty therein. Lake does not undertake to update any forward-looking information, except in accordance with applicable securities laws. 7 Maiden Ore Reserve Report The Project background and modelling work completed to define the Ore Reserve and related Modifying Factors are discussed in the following report. Project Background The Kachi Project is located on the Carachi Pampa basin at the south end of the Puna geographical region, Argentina (Figure 2). The modern-day Puna Region is the southern continuation of the Bolivian Altiplano with an average elevation of 4,400 meters (m) above mean sea level (amsl), although Project elevations are considerably lower, about 3,010 m amsl, which provides considerable advantages from climate and operations perspectives. Figure 2. Kachi Project Location and Layout 8 Property Holdings Lake Resources holds 53 mineral leases (“Minas”) in the Basin covering the surface of the salar and surrounding areas (Figure 3). The mineral leases are summarized in Table 14 (following the text), with the property names, file numbers, and details of the approvals related to each of the concessions. All information regarding the legal status of the properties was provided by Morena del Valle Minerals SA (“MVM”); the local subsidiary of Lake Resources in the Province of Catamarca. The status of properties has not been independently verified by the CP, who takes no responsibility for the legal status of the concessions. Figure 3. Kachi Project Mineral Concessions Note: Galan Oeste and Tornado VII are not currently part of Kachi Project mine plan 9 Geology and Geological Interpretation The Carachi Pampa basin is an arid, closed basin comprised of interbedded lacustrine and alluvial sediments of gravels, sands, silts, and clays, with episodic volcanic deposits of ignimbrites, tuffs, and basalts (Figure 4). The basin is bounded to the east and west by north-south trending mountain ranges formed by thrust faulting exposing basement sequences in outcrops that rise to an elevation of about 5,100 m amsl. The Cerro Blanco pyroclastic complex is located on the south of the basin and is the primary source of the pyroclastic flows that deposited the ignimbrites and tuffs, while the Antofagasta de la Sierra and the Cerro Galan volcanic complex form the highlands in the north and northeast borders of the basin. The ranges to the east are composed of crystalline pre-Cambrian basement that gently slopes down to the basin floor. Red bedded sandstone and claystone sequences of the Geste and Patqia de la Cuesta Formations outcrop in the Los Colorados Range along the western edge of the basin. Extensive alluvial fan deposits were formed to the north, south, east and west of the central salar, as coarse-grained, high-energy sediments were shed from the nearby steep terrains. Altogether the basin drains a watershed area of 9,494 km2. Figure 4. Geology of the Kachi Project Area 10 The center of the basin is dominated by the Quaternary basalt flows and the cider-cone of the Carachi Pampa Volcano. The volcano penetrates basin sediments to the east of the salar, with flow and air fall basalts creating a veneer over the lacustrine sediments. The volcano has a northwest-southeast striking fissure vent that is interpreted to be underlain by a northwest-southeast aligned intrusive dyke or plug of much smaller dimensions than the basalt cone has at the surface. Salars occur in closed basins with no external drainage in dry desert regions where evaporation rates exceed surface and groundwater recharge rates. Evapo-concentration of surface water and groundwater in these basins results in the concentration of dissolved salts that eventually develop saline brines. Two types of salars are classified by Houston et al. (2011) 11:(1) mature, halite dominant, and (2) immature, clastic dominant. Kachi appears to be transitioning from an immature, clastic dominated salar, to a more mature system with the beginning formation of a surficial salt layer with halite that extends to several meters in depth. The salar sediments are predominantly intercalated sands and clayey silts (Figure 5), which constitute a leaky aquifer, with the entire sequence of sediments potentially contributing brine flow to wells. Higher brine flows are obtained from intervals with high sand content and higher permeability, with the brine grades generally comparable between geological units. The salar is surrounded on all sides by alluvial and aeolian fans of varying dimensions and significance. Most important are the Western Fan Complex and the South Fan (Figure 5) that intercept coarse-grained sediments that contain lithium bearing brines. The North Fan is also important due to the presence of both coarse-grained sediments containing lithium bearing brines and a substantial freshwater aquifer. This freshwater overlies the lithium bearing brine. Figure 5. Conceptual hydrogeologic section through the Kachi Project, looking towards the northeast. 11 Houston, J., Butcher, A., Ehren, P., Evans, K., and L. Godfrey. The Evaluation of Brine Prospects and the Requirement for Modifications to Filing Standards. Economic Geology, v. 106, pp. 1225–1239 11 MINERAL RESOURCE An updated resource estimate was released in November 2023 12 and was based on the substantial hydrogeological characterization since the last update in June 2023 13.This update provided refined interpretations of the hydrostratigraphy, hydrogeology, and hydrogeochemistry. For details of the Mineral Resource estimate, readers are referred to the November 22, 2023 ASX announcement and the detailed report included in the Appendix 14 of that announcement. A summary of the Mineral Resource is provided in Table 2 and details of the Mineral Resource classifications are presented in Table 3. A plan view map of the Mineral Resource classifications is provided for 0 to 400 m bgs (Figure 6) and 400 to 600 m bgs (Figure 7), and in 3-dimensions (Figure 8). Table 2. Kachi Project Mineral Resource Summary 15 Resource Category Lithium (Tonnes) LCE (Tonnes) Measured (M) 571,000 3,035,000 Indicated (I) 800,000 4,258,000 M&I 1,371,000 7,293,000 Inferred 630,000 3,352,000 Total Resource 2,001,000 10,645,000 12 See LKE ASX Announcement dated 22 November 2023 13 See LKE ASX Announcement dated 16 August 2023 t 14 Groundwater Exploration Services, 2023, Kachi Resource Estimate Detailed Report. Attachment to November 22 2023 ASX Lake Resources Announcement. 15 Consider notes and details in Table 3 Updated Resource Estimate of Contained Lithium 12 Figure 7 Plan view map of the Indicated Resources (rose), with the surrounding area of Inferred Resource (orange) at a depth of 400 – 600 m 13 Figure 8. Resource Classifications, looking north through the Resource area. 14 Table 3 Updated resource estimate of contained lithium Measured November 2023 (to 400 m depth) Unit Sediment Volume m3 Specific Yield % Brine volume m3 Liters Li mg/L Li grams Li Tonnes Tonnes LCE A 11,001,000,000 0.078 858,078,000 858,078,000,000 210 179,783,644,000 180,000 956,000 B 4,366,100,000 0.081 352,090000 352,090,162,000 229 80,628,647,000 81,000 429,000 C 8,007,400,000 0.068 544,503,000 544,503,200,000 230 125,427,401,000 125,000 667,000 Fan West 8,833,000,000 0.095 839,135,000 839,135,000,000 220 184,609,700,000 185,000 982,000 Total 32,207,500,000 - 2,593,806,000 2,593,806,362,000 - 570,449,393,000 571,000 3,035,000 Indicated November 2023 to 600 m Unit Sediment Volume m3 Specific Yield % Brine volume m3 Liters Li mg/L Li grams Li Tonnes Tonnes LCE A (South) 3,694,300,000 0.076 278,924,000 278,924,452,000 181 50,485,326,000 50,000 269,000 B (South) 1,489,000,000 0.075 111,543,000 111,543,670,000 179 19,959,624,000 20,000 106,000 C (South) 4,382,400,000 0.067 294,407,000 294,407,879,000 182 53,582,234,000 54,000 285,000 A (North) 3,075,200,000 0.095 292,144,000 292,144,000,000 232 67,891,052,000 68,000 361,000 B (North) 4,294,400,000 0.095 407,968,000 407,968,000,000 241 98,166,484,000 98,000 522,000 C (North) 9,188,400,000 0.092 845,333,000 845,332,800,000 182 206,021,447,000 206,000 1,096,000 400 – 600m 12,230,170,000 0.066 806,922,000 806,922,156,000 242 195,275,162,000 195,000 1,039,000 400 – 600m 4,858,200,000 0.092 446,954,000 446,954,400,000 244 109,056,874,000 109,000 580,000 Total 43,212,070,000 3,484,197,000 3,484,197,358,000 800,438,203,000 800,000 4,258,000 1,370,887,596,000 1,371,000 7,293,000 Under Salar West Fan Deep Combined Measured and Indicated 75,419,570,000 6,078,004,000 6,078,003,721,000 Inferred November 2023 Unit Sediment Volume m3 Specific Yield % Brine volume m3 Liters Li mg/L Li grams Li Tonnes Tonnes LCE A 4,756,500,000 0.080 378,325,000 378,325,351,000 185 69,975,435,000 70,000 372,000 B 1,671,300,000 0.079 131,198,000 131,197,886,000 191 25,101,960,000 25,000 134,000 C 5,287,600,000 0.074 393,746,000 393,746,422,000 218 85,950,119,000 86,000 457,000 Fan North 8,895,490,000 0.081 716,324,000 716,324,455,000 232 166,081,974,000 166,000 884,000 Fan South 12,248,490,000 0.064 781,249,000 781,249,112,000 239 186,718,538,000 187,000 993,000 Under volcano 6,718,700,000 0.074 500,471,000 500,471,260,000 192 96,334,211,000 96,000 512,000 Total 39,578,080,000 2,901,314,000 2,901,314,485,000 630,162,237,000 630,000 3,352,000 15  JORC definitions were followed for Mineral resources.  The Competent Person for this Mineral Resource estimate is Andrew Fulton, MAIG.  No internal cut-off concentration has been applied to the resource estimate. The resource is reported at a 150 mg/L cut-off.  Some numbers do not add due to rounding.  Specific Yield (Sy) = Drainable Porosity.  Lithium is converted to lithium carbonate (Li2CO3) with a conversion factor of 5.32. For details on the lithology units please refer to the June 15, 2023, August 22, 2023, and October 4, 2023 ASX announcements. Ore Reserve Estimation An ‘Ore Reserve’ is the economically mineable part of a Measured and/or Indicated Mineral Resource. It includes diluting materials and allowances for losses, which may occur when the material is mined or extracted and is defined by studies at Pre-Feasibility or Feasibility level as appropriate that include application of Modifying Factors. Such studies demonstrate that, at the time of reporting, extraction could reasonably be justified 16. The methodology used to develop estimates of the Mineral Resource Is different from the method used to develop estimates of the brine Ore Reserve. The block (LeapFrog) model, which considers static conditions, is used in estimating the Mineral Resource but cannot estimate the (fluid) brine reserve. The Ore Reserve estimate is based on extraction of the brine that is transmitted in the subsurface in response to well field pumping. As a result, a calibrated hydrogeological model (simulating flow and solute transport) is the most appropriate tool to estimate the brine Ore Reserve through time. This model is described below. Numerical Hydrogeological Model Development A numerical hydrogeologic model (“Model”) has been developed by a collaboration between consultants (Watershed HydroGeo and GES) and the Lake Resources technical team. The Model is a fundamental tool for understanding the hydrogeological system, simulating the brine extraction, and providing quantified estimates of hydrogeological system behaviour as a result of that extraction. Additionally, given that DLE is proposed at Kachi, the spent brine will be returned to the hydrogeologic system in approximately the same proportions that the brine is pumped out of the system. This dynamic interaction of lithium brine extraction with concurrent injection of spent brine is simulated in the Model. The overall Model objectives for the Project are to:  Evaluate various extraction and injection well field layouts and designs to determine which options are preferred for efficient and effective operations.  Verify that planned extraction and injection well designs and the mine plan meet production and injection targets.  Quantify lithium mass through LoM for the proposed well field. The JORC Code 2012 Edition. Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. Effective 20 December 2012. Prepared by the Joint Ore Reserves Committee of The Australasian Institute of Mining and Metallurgy, Australian Institute of Geoscientists and Minerals Council of Australia (JORC) 16 16  Evaluate the effects of spent brine injection and/or natural processes (i.e., capturing of lower concentration lithium brine and/or freshwater dilution) on recovered lithium grades and mass through LoM.  Provide a means for testing various injection well field design scenarios to determine optimal solutions related to minimizing lithium grade dilution and extraction-related effects in environmentally sensitive areas.  Provide estimates to inform Lake Resources of the likely changes to the hydrogeologic system that may result from operation of the extraction and injection well fields from Year 1 to Year 25 including:   drawdown in the production horizons and at the phreatic surface;  changes to baseline fluxes and total dissolved solids in sectors of environmental significance; and  evaluate post-closure conditions and recovery of the hydrogeologic system. Simulate proposed freshwater wells for raw water supply to evaluate whether design yields can be achieved and predict how water use during operations may impact freshwater quantity or quality, if at all. This model assessment has been undertaken with consideration of the Australian Groundwater Modelling Guidelines (“AGMG”) 17. The AGMG was adopted throughout the groundwater industry as a benchmark for best practice. Model design Modelling software For the modelling presented here, the public domain numerical groundwater modelling software MODFLOW-USG-Transport 18 v2.02.1 was used. This is an advanced version of the industry-standard MODFLOW-USG code 19 that was originally developed (and is still supported) by the United States Geological Survey (USGS). Pre-processing and some of the post-processing of model inputs and outputs were carried out via the Groundwater Vistas 20 (v8) graphical user interface, along with executables from the PEST suite 21 of Groundwater Utilities. The SMS numerical solver was used with head closure criteria 0.01 m and a tighter criteria of 1x10-7 m was used for inner iterations to minimize flow and solute transport mass balance errors. Barnett B, Townley LR, Post V, Evans RE, Hunt RJ, Peeters L, Richardson S, Werner AD, Knapton A and Boronkay A., 2012. Australian Groundwater Modelling Guidelines. National Water Commission 17 Panday, S. 2023. MODFLOW-USG-Transport (v2.2.1). GSI. Available at: http:// http://www.gsi-net.com/en/software/freesoftware/USG-Transport.html 18 Panday S, Langevin C, Niswonger N, Ibaraki M, and Hughes J.2013. Chapter A45: MODFLOW-USG Version 1: An unstructured grid version of MODFLOW for simulating groundwater flow and tightly coupled processes using a control volume finite-difference formulation. U.S. Geological Survey Techniques and Methods, Book 6, 66 19 20 ESI, 2020. Groundwater Vistas (v8). https://www.groundwatermodels.com/ESI_Software.php Doherty, J. (2010). Pest: Model-independent parameter estimation, user manual. In Watermark Numerical Computing (5th ed.). PEST Manual. and Doherty, J. (2015). Calibration and uncertainty analysis for complex environmental models. Brisbane, Australia: Watermark Numerical Computing 21 17 Model variants Three versions of the Model were developed for different purposes. All three have consistent model domain or extent, consistent layer geometry, and consistent boundary conditions, other than time variant boundaries. These three models are:  catchment-processes model (longer term historical /calibration model to capture basin scale processes and laguna fluctuations);  pumping-test model (short-term, local scale calibration model focused on the salar); and  predictive model (for forecasting mine operations). The reason for the first two is to focus on longer-term seasonal or annual processes and have a separate model that employs a higher temporal resolution to focus on two pumping and injection tests carried out by Lake in mid-2023. Solute transport and density-dependent flow All model variants simulate two solute transport species (total dissolved solids, TDS and Lithium, Li). They simulate density-dependent f