Exhibit 23.1

CONSENT OF QUALIFIED PERSON

I, Juan Becerra , state that I am responsible for preparing or supervising the preparation of part(s) of the technical report summary titled "Technical Report Summary, Operation Report, Salar de Atacama" with an effective date of April 5, 2024, as signed, and certified by me (the “Technical Report Summary”).

Furthermore, I state that:

Dated at Santiago, Chile on April 5, 2024

Exhibit 23.2

CONSENT OF QUALIFIED PERSON

I, Rodrigo Riquelme Tapia , state that I am responsible for preparing or supervising the preparation of part(s) of the technical report summary titled "Technical Report Summary, Operation Report, Salar de Atacama" with an effective date of April 5, 2024, as signed, and certified by me (the “Technical Report Summary”).

Furthermore, I state that:

Dated at Santiago, Chile on April 5, 2024

Exhibit 96.1

Technical Report Summary

OPERATION REPORT

SALAR DE ATACAMA

Sociedad Química y Minera de Chile

April 5, 2024

TECHNICAL REPORT SUMMARY

OPERATION REPORT

SALAR DE ATACAMA

Sociedad Química y Minera de Chile

April 5, 2024

TABLE OF CONTENTS

TABLES

FIGURES

This Technical Report Summary (TRS) was prepared on behalf of the Sociedad Química y Minera de Chile (SQM) for their operations in the Salar de Atacama (the “Project”). Since the previously filed TRS (2022), it is the QPs’ opinion that there have been no material changes related to exploration, the Mineral Resource, or the Mineral Reserve.

The Project is located in the Antofagasta Region of Chile which covers the Loa Province and San Pedro de Atacama commune. The Salar de Atacama mine tenements are owned by the Corporación de Fomento de la Producción (CORFO) of Chile which grants special operating contracts, or administrative leases, to private companies for the extraction of brine over a certain period. SQM has a lease agreement with CORFO, signed in 1993, to extract and generate lithium (Li) and potassium (K) products from brines in the Salar de Atacama deposit.

In 2018, SQM and CORFO performed a reconciliation process that modified the pre-existing lease and Project contracts. The expiration date of the current SQM-CORFO lease agreement is December 31, 2030, and SQM holds leases for a total area of approximately 1,400 square kilometers (km2) with permission to extract brines from an area of approximately 820 km2.

The general geology of the Salar de Atacama Basin is characterized by Paleozoic to Holocene igneous and sedimentary rocks as well as recent, unconsolidated clastic deposits and evaporitic sequences. The salt flat resides in a tectonic basin, where important subsidence and sediment deposition have historically occurred. Over time, the process of evaporation has precipitated salts, and at depth, evaporitic, clastic, and volcanic ash deposits host brine. Several structural blocks and fault systems have been identified, where displacement and deformation of the geological units have occurred.

According to Houston et. al. (2011), the Salar de Atacama is a mature salt flat with mineralization characterized by Li- and K-rich brine, residing in the porous media of the subsurface reservoir along with elevated concentrations of other dissolved constituents (e.g., boron and sulfate). The explored reservoir covers an area of 1,100 km2 and depth of up to 900 meters (m), where a thick section of halite (> 90%) and sulfate can be found in addition to a minor percentage of clastic sediments, volcanic ash, and interbedded evaporites (Bevacqua, 1992; Xterrae, 2011). The arithmetic mean concentrations of Li and K from all brine samples (and all units) correspond to 0.187 weight percent (wt.%) and 1.867 wt.%, respectively.

This sub-section contains forward-looking information related to Mineral Resource estimates for the Project. The material factors that could cause actual results to differ materially from the conclusions, estimates, designs, forecasts, or projections in the forward-looking information include any significant differences from one or more of the material factors or assumptions that were set forth in this sub-section including geological and grade interpretations, as well as controls, assumptions, and forecasts associated with establishing the prospects for economic extraction.

SQM’s Mineral Resource estimate for the Salar de Atacama comprises in-situ Li- and K- enriched brine situated below the surface of the salt flat. The Mineral Resource estimates include consideration of brine concentration, reservoir geometry, and drainable, interconnected pore volume. Within SQM’s leased mining concessions, the Mineral Resource is supported by extensive exploration and a large dataset of depth-specific brine and porosity samples from each unit. A geological model was developed, using Leapfrog Geo software, from which the block model was constructed, and the Mineral Resource was estimated using Leapfrog Edge.

The Mineral Resource was classified into Measured, Indicated, and Inferred categories, according to the amount of information from the hydrogeological units as well as geostatistical criteria. Hydrogeological knowledge was prioritized based on exploration, monitoring, and historical production data, while geostatistical variables were used as secondary criteria.

The in-situ Li and K Mineral Resource estimate, exclusive of Mineral Reserves (without processing losses), is summarized in Table 1-1. Mean Li and K grades are reported above the designated cut-off grades of 0.05 wt.% for Li and 1.0 wt.% for K. This indicates that the prospective extraction of the Mineral Resource is economically feasible (see Section 11.2 of this Technical Report Summary [TRS] for additional discussion on the cut-off grades).

Table 1-1. SQM’s Salar de Atacama Lithium and Potassium Mineral Resources, Exclusive of Mineral Reserves (Effective December 31, 2023)

Notes:

(1) Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the Mineral Resource will be converted into Mineral Reserves upon the application of modifying factors.

(2) Mineral Resources are reported as in-situ and exclusive of Mineral Reserves, where the estimated Mineral Reserve without processing losses during the reported LOM (Chapter 12) and real declared extraction from 2021 were subtracted from the Mineral Resource inclusive of Mineral Reserves. A direct correlation between Proven Reserves and Measured Resources, as well as Probable Reserves and Indicated Resources was assumed.

(3) Compared to the previously filed TRS (2022), mining occurred in 2023 and the end of the LOM (year 2030) has not changed. Given the acceptable reserve model fit to real 2023 production (see Chapter 12), there is no change in the Mineral Resource exclusive of Mineral Reserves since December 31, 2022 (SQM, 2023).

(4) Effective porosity was utilized to estimate the drainable brine volume based on the measurement techniques of the SQM porosity laboratory (Gas Displacement Pycnometer). Although specific yield is not used for the estimate, the QP considers that the high frequency sampling of effective porosity, its large dataset, and general lack of material where specific retention can be dominant permits effective porosity to be a reasonable parameter for the Mineral Resource estimate.

(5) The conversion of brine volume to Li and K tonnes considered the estimated brine density in each block model cell.

(6) Comparisons of values may not add due to the rounding of numbers and differences caused by use of averaging methods.

(7) The Mineral Resource estimate considers a 0.05 wt.% cut-off grade for Li based on the cost of generating Li product, lithium carbonate sales, and the respective cost margin. Based on historical lithium prices from 2010 and the forecast to 2040, a projected lithium carbonate price of $ 11,000 USD/tonnes with the corresponding cost and profit margin are considered with a small increase to accommodate the evaporation area and use of additives. A similar pricing basis and analysis was undertaken for K, where the cut-off grade of 1 wt.% was set by SQM based on respective costs, sales, and margin (Section 16 and Section 19).

This sub-section contains forward-looking information related to Mineral Reserve estimates for the Project. The material factors that could cause actual results to differ materially from the conclusions, estimates, designs, forecasts or projections in the forward-looking information include any significant differences from one or more of the material factors or assumptions that were set forth in this sub-section including Mineral Resource model tonnes and grade, modifying factors including pumping and recovery factors, production rate and schedule, equipment and plant performance, commodity market and prices, and projected operating and capital costs.

A groundwater flow and solute transport model was developed using the Groundwater Vistas interface and Modflow-USG code to evaluate the extraction of Li and K-rich brine from pumping wells during the 7-year life-of-mine (LOM). The numerical model was constructed based on the geometry of the geological and resource block model parameters. The transfer of relevant resource estimate parameters (concentrations and effective porosity) was performed to ensure consistency between the Resource and Reserve model properties. To confirm sufficient calibration of the aquifer parameters (e.g., hydraulic conductivity) and representation of the water balance components in the salt flat nucleus, the numerical model was calibrated to observed brine levels and extracted brine concentrations during the 2015 to 2020 period. Extracted mass was subsequently verified for the 2021 to 2023 period.

The Mineral Reserve estimate considers the modifying factors of converting Mineral Resources to Mineral Reserves, including the production wellfield design and efficiency (e.g., location and screen of the production wells), environmental considerations (e.g., pumping schedule), and recovery factors for Li and K. The simulated mass of extracted Li and K after 7 years of pumping is summarized in Table 1-2. The table considers process recovery factors, where the model extracted mass at the production wellheads, was multiplied by a pond recovery factor associated with the type of extracted brine. Thus, the reserve was estimated from the point of reference of processed brine after passing through the evaporation ponds (rather than at the production wellheads).

The Mineral Reserve was classified into Proven and Probable Reserves based on industry standards for brine projects, the Qualified Person’s (QP’s) experience, and the confidence generated by SQM’s historical production in the Salar de Atacama. A majority of the extracted mass is sourced from Measured Resources; nonetheless, Proven Reserves were specified by the QP for the first 3 years given the adequate model calibration during the 2015-2020 period and overall verification of simulated production in 2021, 2022 and 2023. Probable Reserves were conservatively assigned for the last 4 years of the LOM considering that the numerical model will be continually improved and recalibrated in the future due to potential changes to neighboring pumping, hydraulic parameters, and the water balance, among other factors.

Table 1-2. SQM’s Salar de Atacama Lithium and Potassium Mineral Reserves, Factoring Process Recoveries (Effective December 31, 2023)

(1) The process efficiency of SQM is summarized in Section 12.4.1; based on the type of extracted brine at each well over the course of the simulation, the average process efficiency is approximately 52% for Li and approximately 75% for K.

(2) Lithium carbonate equivalent (“LCE”) is calculated using mass of LCE = 5.323 multiplied by the mass of lithium metal and potassium chloride equivalent (“KCl”) is calculated using mass of KCl = 1.907 multiplied by the mass of potassium metal.

(3) The values in the columns for “Li” and “LCE”, as well as “K” and “KCl”, above are expressed as total contained metals.

(4) The average lithium and potassium concentration is weighted by the simulated extraction rates in each well, and it is subsequently weighted by pumping over the indicated period.

(5) Comparisons of values may not add due to the rounding of numbers and differences caused by averaging.

(6) The Mineral Reserve estimate considers a 0.05 wt.% cut-off grade for Li based on the cost of generating Li product, lithium carbonate sales, and the respective cost margin. Based on historical lithium prices, a projected lithium carbonate price of $ 11,000 USD/tonnes with the corresponding cost and profit margin is considered with a small increase to accommodate the evaporation area and use of additives. A similar pricing basis and analysis was undertaken for K where the cut-off grade of 1 wt.% has been set by SQM based on respective costs, sales, and margin (Section 16 and Section 19).

(7) This Reserve estimate differs from the in-situ base Reserve previously reported (SQM, 2020) and considers the modifying factors of converting mineral resources to Mineral Reserves, including the production wellfield design and efficiency, as well as environmental and process recovery factors.

It is the QP’s opinion that the declared Reserve estimate and corresponding methods conform with the SEC regulations. Furthermore, the reserve classification is believed to be conservative, given that SQM’s brine production has been ongoing for decades. The presented analysis includes a detailed calibration process and time-based reserve classification to account for potential future changes in hydraulic parameters (with more field data and testing), the water balance, and neighboring pumping, among other factors.

In the Salar de Atacama, SQM’s mining method corresponds to brine extraction. Production is characterized by the construction of pumping wells capable of extracting brine from different reservoirs of interest. Subsequently, the brine extracted from each of the production wells is accumulated in gathering ponds for distribution to evaporation ponds and metallurgical plants.

Due to limitations of the SQM-CORFO lease agreement, the current mine life ends on December 31, 2030. Until this date, the expected brine production had been evaluated with a decreasing total brine extraction rate from 1,159 L/s (2024) to 822 L/s (2030).

The developed test work is aimed at estimating the response of different brines by concentration, via solar evaporation, and overall metallurgical recoveries of the process plants, in addition to assessing raw material treatability for finished lithium and potassium products.

SQM employees regularly collect brine samples and complement this by considering temporal, geological, spatial, and operational criteria of the wells, with an emphasis on maintaining an updated and accurate dataset of brine chemistry characteristics. The Salar de Atacama laboratory, through its facilities, generates metallurgical assay databases which include the chemical composition, density, and porosity test results, among other assays which allow for process control and planning.

Historically, SQM has analyzed the different plant and/or pilot scale tests through its Research and Development Area, allowing them to improve the recovery process and product quality. Currently, there is a plan to increase yield at the Salar de Atacama which consists of a series of operational improvement initiatives, development and expansion projects, as well as new process evaluations to recover a greater amount of lithium in the LiCl production system.

SQM has developed a process model to convert the brine extracted from available salt properties containing potassium, lithium, sulfates, boron, and magnesium into commercial potassium and lithium salts products. The process follows industry standards, considering the stages of brine pumping from the reservoirs to concentrate it by sequential evaporation, treating the harvested potassium salts to obtain refined salts, and treating the brine concentrate in a plant to produce high quality lithium carbonate and lithium derivatives.

Thus, the objective of the Project is to produce potassium salts, such as potassium chloride (KCl) and potassium sulfate (K2SO4), as well as lithium salts such as lithium carbonate (Li2CO3) and lithium hydroxide (LiOH). There are two production lines, one focused on obtaining potassium products (SQM Salar de Atacama process plants), and another concentrated on the production of lithium carbonate and hydroxide (SQM Carmen Lithium Chemical Plant), both of which are two facilities that make up SQM’s Salar de Atacama operations.

SQM's production process is characterized by being integrated (i.e., exchanging raw materials and products with each other). The Carmen Lithium Chemical Plant (PQC), located near Antofagasta, has production facilities that comprise a Lithium Carbonate Plant and a Lithium Hydroxide Plant. The production capacity of the lithium carbonate plant at PQC until the year 2021 was 120,000 tonnes per year (Mtpy), and at that time, it was projected to increase production to 180,000 tonnes per year (Mtpy). Additionally, the lithium hydroxide plant had a production capacity of 21,500 tonnes per year (Mtpy), with plans to increase production capacity to 30,000 (Mtpy). However, the current production is now 150,000 (Mtpy), with plans to increase production to 210,000 Mtpy. Furthermore, the lithium hydroxide plant has a production capacity of 24,500 Mtpy, with plans to increase production capacity to 32,500 Mtpy.

This section contains forward-looking information related to capital and operating cost estimates for the Project. The material factors that could cause actual results to differ materially from the conclusions, estimates, designs, forecasts or projections in the forward-looking information include any significant differences from one or more of the material factors or assumptions that were set forth in this section. These include prevailing economic conditions which continue in a manner that the unit costs are as estimated, projected labor and equipment productivity levels are maintained, and that contingency is sufficient to account for changes in material factors or assumptions.

SQM is the world’s largest producer of potassium nitrate and iodine, and one of the world’s largest lithium producers. It also generates specialty plant nutrients, iodine derivatives, lithium derivatives, potassium chloride, potassium sulfate, and certain industrial chemicals (including industrial nitrates and solar salts). The products are sold in approximately 110 countries through SQM’s worldwide distribution network, with more than 90% of the sales derived from countries outside of Chile.

The facilities for lithium and potassium production operations include brine extraction wells, evaporation and harvest ponds, lithium carbonate and lithium hydroxide production plants, dry plants and wet plants for potassium chloride and sulfate, as well as other minor facilities. Offices and services include common areas, hydrogeological assets, water resources, supply areas, powerhouse, laboratories, and research areas.

At the end of 2020, the capital cost that had been invested (reposition cost) in these facilities was close to 2,300 million dollars. The cost of capital distributed in the areas related to lithium and chloride and sulfate potassium production is shown in Table 1-3. As indicated, the main investments in lithium and potassium production are the “Lithium Carbonate and Lithium Hydroxide Plants”, as well as the “Evaporation and Harvest Ponds”, accounting for about 55% of the total investment.

Table 1-3. Capital Costs for Lithium and Potassium Operations

The main investment in the lithium carbonate plant, which represents about 81% of the lithium plants, are in buildings, mechanical equipment, such as filters, pumps, valves, pipes, ponds, and drying equipment. For the Evaporation and Harvest Ponds, the main investments are in the MOP (Muriate of Potash) I and II, and SOP (Sulfate of Potash) ponds, accounting for 83% of the total investment in the ponds.

SQM has plans to continue the capacity expansion of its plants, complying with the CORFO quota agreements. As mentioned in Chapter 1.6.2, the production capacity and projected production increase until the year 2021 of the lithium carbonate plant in PQC were 120,000 tons per year and 180,000 tons per year, respectively. Also, for the same year, the lithium hydroxide plant had a production capacity and a projected production capacity increase of 21,500 tons per year and 30,000 tons per year, respectively.

The highest operating cost is in the CORFO rights and other agreements, representing about 79% during 2022. The other major item in raw material and consumables, employee benefit expenses, depreciation expense, and contractor works, representing 18% of the operating cost.

During the first 9 months of 2022, the operating cost that has been spent to produce lithium and potassium chloride and sulphate at the Salar de Atacama and Salar del Carmen plants was close to 2,900 million dollars.

This section contains forward-looking information related to economic analysis for the Project. The material factors that could cause actual results to differ materially from the conclusions, estimates, designs, forecasts, or projections in the forward-looking information include any significant differences from one or more of the material factors or assumptions that were set forth in this sub-section including estimated capital and operating costs, project schedule and approvals timing, availability of funding, projected commodities markets, and prices.

The Economic Analysis considers the actual concession agreement with CORFO, as it is at the end of 2023, where the Project Agreement expires on December 31, 2030. SQM declares that, on December 27, 2023, SQM and Codelco, Chilean state-owned company which had been mandated by the Chilean Government to negotiate its participation in the lithium operations in the Salar de Atacama, signed a memorandum of understanding (MoU), which, among other matters, established the ground terms and conditions for the definitive agreements which will allows SQM Salar to exploit mineral resources in the Salar de Atacama until 2060. The full text of the MoU is referenced in the Exhibit 94.4 of the Report on Form 20-F. See also “— Risks Relating to Chile — The new National Lithium Strategy announced by the Chilean government in April 2023 has created and may continue to create uncertainty in the Chilean lithium industry, which could have a material adverse effect on our business performance or the value of our shares and ADSs.” The definitive agreements are subject to negotiation and we cannot guarantee that said agreements will be implemented.”

To obtain an income flow in relation to the production of Li2CO3, LiOH, and KCl for the period of 2024 to 2030 with the investments projected for a 210 ktpy carbonate plant and 100 ktpy hydroxide plant expansion have been considered. In the case of the long-term price of Li2CO3, a base value of 12,110 USD/tonne has been considered with a long-term KCl price of 300 USD/ton. The price of LiOH was assumed to be 5% higher than the price of Li2CO3. As it is shown in Figure 16 4, it is important to note that lithium prices have had an unexpected behavior: at the end of 2022 and 2023, the lithium price was close to 78,000 and 13,500 USD/tonne respectively. For this analysis, a conservative scenario is assumed, based in the market study described in chapter 16, where the long term lithium carbonate price at 12,110 USD/tonne will be required to sustain new project development. Table 1-4 shows the main assumptions taken for the base case.

Table 1-4. Assumptions for the Base Case Economic Analysis

(*) Price of K defined according to the application of its products and derivatives.

The projected sales of lithium carbonate, lithium hydroxide and potassium chloride for the LOM until 2030 is presented in Table 1-5.

Table 1-5. Projected Sales of Lithium and Potassium Products

Note: Reserves of Chapter 12 are declared based on brine recovery factors associated with the evaporation ponds (i.e. the point of reference being after passing through the evaporation ponds), while the final sales product is presented here; note that values are rounded if comparing totals.

The Net Present Value (NPV) estimates for Salar de Atacama and PQC production are provided in Table 1-6.

Table 1-6. Estimated Cashflow Analysis

This study concludes that the Salar de Atacama Project in operation for the treatment of brines to obtain Li and K salts is economically feasible, according to financial and reserve parameters. Furthermore, SQM has vast experience in the treatment of brines and salts. Their track record includes knowledge of the Mineral Resources and raw materials during the different processing stages, including operational data on reagent consumption and costs.

All reported categories were prepared in accordance with the resource classification pursuant to the SEC's new mining rules under subpart 1300 and Item 601(96)(B)(iii) of Regulation S-K (the "New Mining Rules").

This Technical Report Summary (TRS) was prepared for the Sociedad Química y Minera de Chile (SQM) and its aim is to provide investors with a comprehensive understanding of the mining property based on the requirements of Regulation S-K, Subpart 1300 of the United States Securities Exchange Commission (SEC), which hereafter is referred to as the SK-1300.

SQM produces a wide variety of commercial chemicals from the naturally occurring brines in the Salar de Atacama salt crust found in northern Chile. Products derived from the brines include potassium nitrate, lithium derivatives, iodine derivatives, potash, and other industrial chemicals.

This TRS provides technical information to support Mineral Resource and Mineral Reserve estimates for the operations of SQM in the Salar de Atacama (the Project). It also details related brine processing information in the Carmen Lithium Chemical Plant (PQC).

The effective date of this TRS Report is April 8, 2023, while the effective date of the Mineral Resource and Mineral Reserve estimates is December 31, 2023. It is the QP’s opinion that there are no known material changes impacting the Mineral Resource and Mineral Reserve estimates between December 31, 2023, and April 8, 2024.

This TRS uses English spelling and Metric units of measure. Grades are presented in weight percent (wt.%). Costs are presented in constant US Dollars (USD), as of December 31, 2022.

Except where noted, coordinates in this TRS are presented in Metric units, using the World Geodetic System (WGS) 1984 Universal Transverse Mercator (UTM) ZONE 19 South (19S).

The purpose of this TRS is to report Mineral Resources and Mineral Reserves for SQM’s Salar de Atacama operation.

Table 2-1 details the acronyms and abbreviations used in this TRS.

Table 2-1. Acronyms and Abbreviations

This TRS is based on information provided by SQM. All the utilized information is cited throughout this TRS and is referenced in Chapter 24 (References) at the end of this Report.

The details of the site inspections by the QPs are summarized in Table 2-2.

Table 2-2. Site visits

During the various site visits, the QPs toured the general areas of mineralization, the historical and current mine, as well as the drill sites. The group also reviewed existing infrastructure, evaporation ponds, processing plants, wells, drill cores, and project data files with SQM technical staff.

This is the second TRS prepared for SQM's Salar de Atacama brine deposit. This TRS is an update of a previously filed TRS (2022).

The Salar de Atacama Basin is located in the El Loa Province, within the Antofagasta Region of northern Chile, between 548,420 mE and 589,789 mE and 7,394,040 mS and 7,393,788 mS (Coordinate Reference System WGS84, UTM 19S). As shown on Figure 3-1, the mining property operated by SQM extends between approximately 550,000 mE and 593,000 mE, and 7,371,000 mS and 7,420,000 mS (Coordinate Reference System WGS84, UTM 19S). SQM’s distinct areas of exploration (OMA Exploration) and extraction (OMA Extraction) are detailed in the following subsection.

Figure 3-1. Location of SQM’s Salar de Atacama Project

In 1993, SQM entered a lease agreement with the Corporación de Fomento de la Producción or Production Development Corporation of Chile (CORFO), the governmental agency that owns the mineral rights in the Salar de Atacama. The lease between CORFO and SQM will last until December 31, 2030, granting SQM exclusive rights to Mineral Resources beneath 140,000 hectares (ha) (28,054 mineral concessions) of the Salar de Atacama. SQM is permitted to extract minerals from a subset of 81,920 ha (16,384 mineral concessions), corresponding to 59.5% of the total area of the leased land. The 140,000 ha of land leased by CORFO to SQM are referred to as the “OMA” concessions, a name devised by CORFO in 1977. SQM refers to the 81,920-ha subset, where extraction can occur as the “OMA Extracción” (OMA Extraction) Area. The remaining 58,350 ha are termed the “OMA Exploración” (OMA Exploration) Area, where only mineral exploration can occur. The terms of the agreement established that CORFO will not allow any other entity aside from SQM to explore or exploit any Mineral Resource in the indicated 140,000 ha area of the Salar de Atacama.

In 2018, SQM and CORFO undertook a reconciliation process that modified the pre-existing lease and project contracts. As part of this Arbitration Agreement, SQM generated additional resources for the state and local communities of Antofagasta as well as for research and development. The expiration date of the lease (December 31, 2030) was not modified. Regarding brine production, in the lease agreement, Comisión Chilena de Energía Nuclear, or Chilean Nuclear Energy Commission (CCHEN) established a total accumulated sales limit of up to 349,553 tonnes of metallic lithium (1,860,670 tonnes of lithium carbonate equivalent) in addition to approximately 64,816 tonnes of metallic lithium (345,015 tonnes of lithium carbonate equivalent) remaining from the originally authorized quantity of the CORFO Arbitration Agreement of 2018.

The environmental permit, “Resolución de Calificación Ambiental, RCA N° 226/2006,” issued on October 19, 2006, by the Comisión Regional del Medio Ambiente, or Regional Environmental Commission (COREMA), authorizes SQM to extract brines via pumping wells from a specific portion of the OMA Exploration Area. SQM refers to these brine extraction areas as Áreas Autorizadas para la Extracción, or Authorized Areas of Extraction (AAE) zones, and they are further divided based on the products historically generated in each sector (Figure 3-1). The northern portion is denominated the AAE-SOP, where “SOP” signifies sulfato de potasio (potassium sulfate product) and covers a surface area of 10,512 ha equivalent to 29.27% of the total AAE area. The southern portion is referred to as AAE-MOP, where “MOP” indicates muriato de potasio (potassium chloride product), covering a surface area of 25,399 ha equivalent to 70.73% of the total AAE area.

The water that SQM uses for its mineral production in the Salar de Atacama is obtained from wells located in the alluvial aquifer on the eastern edge of the salt flat, for which the company has rights and the corresponding environmental authorization (RCA 226/2006) to use groundwater. As part of the voluntary sustainability commitment assumed by SQM in 2020, the company will reduce its water consumption by up to 50% in 2030 (SQM I, 2021).

SQM’s operations are subject to certain risk factors that may affect the business, financial conditions, cashflow, or SQM’s operational results. Potential risk factors are summarized below:

SQM made payments to the Chilean government for the exploration and exploitation concessions, including those which are leased from CORFO of approximately US $ 7.9 million in 2019 and US $ 6.5 million in 2020. These payments do not include those made directly to CORFO by virtue of the lease agreement, according to the established percentages related to the sale value of the resulting products of brine exploitation (Table 3-1)

SQM does not have contracts that require other payments for: licenses, franchises, or royalties (not contemplated in the Royalty Law of Chile). SQM carries out its own operations through mining rights, production facilities, as well as transportation and storage facilities.

Table 3-1. Payment Agreements with CORFO

Payments 1

Source Company

(1) Effective as of April 10, 2018

(2) % of final sale price

(3) % of FOB price

The Salar de Atacama salt crust covers an area of approximately 2,200 km2 with a greater north-south distance of 85 km and maximum west-east width of 50 km. The average elevation of the salt flat nucleus is approximately 2,300 meters above sea level (masl).

Vegetation is mainly found along the marginal zone of the basin and is associated with a desert ecosystem and low-precipitation environment (SRK, 2020). There are four main vegetation types in the basin which correspond to crops, vegas, tamarugos, and bofedales.

The SQM facilities of Salar de Atacama Project are located 35.6 km from Peine and at 57.4 km from Toconao. The closest cities are Calama, located 160 km to the west of the basin, and Antofagasta, which is located 230 km to the west.

It is possible to travel to site by plane, via the Loa Airport, or Andrés Sabella Airport, located in Calama and Antofagasta, respectively. From Calama, the road to the site is through Route R-23 over 220 km, and from Antofagasta, it is via Route B-385 for 272 km. It is also possible to access the area through two public roads, Route B-355 that runs from Toconao to Peine, as well as Route B-385 which connects Baquedano to the Salar de Atacama.

Recorded temperatures at the SQM station Campamento Andino vary between -6 degrees Celsius (°C) and 33°C, with an annual average lower than 18°C, which is characteristic of a cold desert environment.

Precipitation is registered both in the winter and summer, with a majority of the precipitation occurring in summer (December, January, and February). Maximum values range between 29.3 mm (KCL Station, March 2002) and 88 mm (Toconao Station, February 2012). Operations occur year-round (continuously), with higher evaporation rates in the summer and lower rates in winter.

Since 2017, the operations at Salar de Atacama are connected to the national electrical system that provides energy to most of the cities and industries in Chile. Most energy needs are covered by the Electric Power Supply Agreement which was enacted with AES Gener S.A. on December 31, 2012. For natural gas, SQM has a five-year contract with Engie since 2019, and liquid gas is supplied by Lipigas. The freshwater supply for the Salar de Atacama is obtained from nearby freshwater wells in the basin for which the company has the corresponding rights and environmental authorization.

Between 1994 and 1999, SQM invested in the development of the Salar de Atacama Project to produce potassium chloride, and lithium carbonate among other products (SQM, 2020). Prior to SQM’s involvement in the Project, numerous historical studies were completed in the Salar de Atacama Basin to investigate the geology, surface and groundwater hydrology, hydrogeochemistry, and water and brine resources. The most relevant technical studies, previous operations, and relevant exploration and development work are summarized below:

The focus of the mineralization for the Project is lithium and potassium bearing brine, occurring within the aquifer in SQM’s mining concessions of the Salar de Atacama. The following subsections summarize the regional, local, and property geology as well as the mineralized zones and deposit type.

The general geology in the vicinity of the Project is characterized by Paleozoic to Holocene igneous and sedimentary rocks, as well as recent unconsolidated clastic deposits and evaporitic sequences. The salt flat itself resides in a tectonic basin of important subsidence and recent compressive-transpressive behavior. It is bounded by high angle reverse and strike-slip faults that have affected the Paleozoic basement to current cover (Jordan et al., 2002; Mpodozis et al., 2005; Arriagada et al., 2006; Jordan et al., 2007). Toward the south of the salt flat, the Cordón de Lila igneous-sedimentary complex is found; and in the north-central portion, surficial sediments are present that are associated with the San Pedro River Delta.

Since the Mesozoic Era, the space generated from regional faults movements has controlled the deposition of the distinct geological formations in the area, as well as current morphology (Mpodozis et al., 2005; Arriagada et al., 2006). The basement rock represents the oldest consolidated units of the Salar de Atacama Basin that outcrop in the higher peaks of the Cordillera de Domeyko and Cordón de Lila. It is constituted by Paleozoic to Paleocene intrusive rocks, Paleozoic fluvial and marine deltaic sequences, as well as Paleozoic to Cretaceous continental and volcanic sequences. These outcrops are partially covered by continental sedimentary sequences.

Consolidated ash flows from ignimbrite deposits of the Miocene age to present day unconformably overlie basement rock and cover large areas of the Cordillera Occidental and slopes of the Cordón de Lila. Furthermore, Oligocene to Holocene unconsolidated deposits of alluvial, fluvial, and eolian origin outcrop Llano de la Paciencia, west of Cordillera de la Sal, as well as along the slopes of Cordón de Lila.

The surficial geology in the Salar de Atacama area comprises recent evaporitic deposits, where over time, the process of evaporation has precipitated salts, as well as unconsolidated surficial sediments along the salt flat margins (Figure 6-1). The salt crust principally comprises halite, sulfates, and occasional organic matter. With depth, evaporitic, clastic, and thin volcanic ash deposits host brine delimitated and cut by local fault systems. Several structural blocks were identified due to observed displacement and deformation of the geological units (Chapter 7).

The north-northwest-south-southeast (NNW-SSE) trending Salar Fault System is the most important structural system, spanning from the southern limit of the San Pedro River Delta and deepening toward the north (Arriagada, 2009). Within the Salar de Atacama, the high angle reverse Salar Fault represents the most important structural feature with significant displacement of the lithologic units on either side, defining two main structural domains, the West Block and East Block (Figure 6-1). Another important fault system in the salt flat that corresponds to the Cabeza de Caballo Fault System that extends from the Lila Mountain to the north. Several other NNW-SSE trending faults systems were also identified.

Figure 6-1. Local Geology Map of Salar de Atacama

The stratigraphic units within the property are briefly described and presented below from youngest to oldest (SQM, 2021). The following sub-section presents geological cross sections through the property geology and the general stratigraphic sequence (Figure 6-2 and Figure 6-3).

This unit comprises pure halite and halite with clastic sedimentary material and/or gypsum. The clastic sedimentary material comprises clay, silt, and sand, which are more abundant near surface and decrease with increasing depth. The Upper Halite has a mean thickness of 17 m in the West Block and 23 m in the East Block. In the West Block, the Upper Halite is underlain by clay, gypsum, or carbonate units, depending on the specific area. In the East Block, the Upper Halite overlies halite with organic matter.

Clastic and evaporitic unit underlying the Upper Halite, which is mainly constituted by plastic clays, evaporites (halite and gypsum) and carbonates. This unit is mainly recognized in the West Block, and it presents a variable thickness between 0.3 m and 16 m, with a mean thickness of 1 m. This unit also includes two clay layers located in the SW and NW areas of the West Block.

This unit is mainly constituted by halite with interbedded gypsum, carbonates, and organic matter (black to gray colored). It is found in the East Block, with a minimum thickness of 3 m near the Salar Fault and maximum thickness of 242 m along the eastern edge of the salt flat (with a mean thickness of 64 m throughout the area). This unit separates the Upper Halite unit from the Intermediate Halite Unit in the East Bock.

The Intermediate Halite is divided into three distinct blocks according to observed spatial differences: (i) Northwest Block from the coordinate 7,385,626 5 m S, (ii) Southwest Block from the coordinate 7,385,626 m S, and the East Block. The three blocks are characterized by pure halite and halite with clastic sedimentary material and/or gypsum, with less than 25% of intercrystallite and intracrystalline content. In the East Block, minor traces of organic matter and carbonates are also present.

The Intermediate Halite unit thickness differs between the West Block and East Block: in the northwest (West Block), its maximum thickness is 25 m, while in the East Block, its maximum thickness reaches 429 m (with a mean thickness of 238 m).

The Evaporite and Intermediate Volcanoclastic Unit represents an erosional unconformity and is composed of interbedded gypsum, tuff, and reworked volcanoclastic material. In total, at least 10 tuff layers are found in this unit that are affected by local wedging, folding, and truncation. Toward the north of the salt flat, a change of facies is present where the gypsum grades to halite and the thickness increases (to the north) and is wedged to the south.

In the western block, this sequence has a recognized thickness of between 0 and 157 m and a mean thickness of 84 m. Its top, on average, is located at a depth of 51 m below the surface of the salt flat. Between the Salar and Cabeza de Caballo Faults, a sequence of sediments and evaporites called Sequence 1 is found which composed mainly of clay, halite, and gypsum. This sequence decreases towards the south and towards the Salar Fault, with thickness ranging from 7 to 36 m and a mean thickness of 20 m, where its greatest thickness is observed in the SOP deposit.

In the East Block, the Intermediate Evaporitic and Volcanoclastic unit is similar in composition to that described in the West Block. The only difference is that its mean thickness is on the order of 100 m, and the top of this unit is located at a mean depth of 318 m below surface.

The Lower Halite comprises pure halite, halite with clasitic sedimentary material and/or gypsum, as well as halite with clay and/or sand. The halite generally presents a mosaic texture, and the clastic sedimentary material represent less than 25% of the rock, and they are clays, silt, and brown to red sands. The gypsum content represents less than 10% of the unit.

This unit is recognized in both West and East Blocks; in the West Block it has a variable thickness with a mean of 69 m in the West Block.

A deep layer of clays, with a minimum depth below land surface of 60 m (West Block) and maximum depth below land surface of 400 m (East Block). This unit represents an erosional unconformity according to the seismic profile interpretation (Arriagada et al, 2006 ).

Underlaying the shallower sections of the Regional Clays, a deep tuff layer can be found with a mean thickness of 5 m. It consists of a thin crystalline - pumice tuff with abundant biotite, feldspars, and sparse quartz.

Two cross sections of the geological units that intersect the SQM properties are shown in Figure 6-2; this geological model was built using the Leapfrog Geo software and is based on well lithologic logs as well as geophysical sections (Chapter 7; SQM, 2020). In the referenced figures, the various lithologic units are displayed with depth.

As a result of fault displacement and deformation, the East and the West blocks of the Salar de Atacama present important differences in the depths of the lithologic contacts. The west-east cross section highlights the displacement of the units due to the Salar and Cabeza de Caballo faults and shows the deepening of the units in the East Block. In the north-south cross section, the gypsum grades to halite toward the north, and its thickness increases 60 m.

Figure 6-2. Geological Cross Sections

Two stratigraphic columns representing the West and East blocks are also presented in Figure 6-3. The most recently characterized type column for the East and West blocks were developed in 2018 by the Hydrogeology Department of SQM (i.e., GHS) using lithologic information from diamond drillholes.

Figure 6-3. Stratigraphic Columns of the Western and Eastern Blocks

The Salar de Atacama brine deposit is contained within porous media filled with interstitial brine rich in Li, K, and boron among other ions. Houston et al. (2011) defined two types of salt flats, mature and immature salt flats:

Figure 6-4 shows the different distribution of facies and main lithological components in both mature and immature salt flats classifications.

The Salar de Atacama nucleus is constituted by a thick section of evaporites over a surface area of 1,100 square km and up to a depth of 900 m (Bevacqua, 1992; Xterrae, 2011). (Arriagada, 2009). It is surrounded by a marginal zone of clastic sediments over an area of about 2,000 square km of extension (Díaz del Río et al., 1972). The nucleus is mainly constituted by halite (>90%) with sulfate and a minor percentage of clastic sediments as well as some interbedded clay sediments and sulfates. Therefore, the Salar de Atacama is classified as a mature salt flat, according to the site geology and Houston, et al. (2011) classification.

Figure 6-4. Mature and Immature Salt Flats (Houston et al., 2011)

This chapter provides an overview of exploration work that has contributed to the development of the geological and hydrogeological conceptual models of the Project.

Geophysical information collected and utilized by SQM includes data obtained from surface survey lines and downhole geophysical instruments deployed in wells. The surface geophysical dataset is comprised of data collected by the transient electromagnetic method (TEM), nanoTEM, Electrical Resistivity Tomography (ERT), Magnetotelluric method (MT), and seismic reflection. The downhole geophysical dataset complements the geological, stratigraphical, and hydrogeological logging of wells, providing guidance for the cross correlation of stratigraphic units between holes to facilitate the continual improvement of the 3D stratigraphic, structural, and hydrogeological models of the salt flat. Downhole logs routinely run by SQM in the drilled wells include Caliper logs, Natural Gamma, and Borehole Nuclear Magnetic Resonance (NMR/BMR, Vista Clara Inc). Each layer (stratigraphic unit) presents a characteristic combination of responses to these three logs, assisting in the cross-correlation of stratigraphy.

Seismic reflection surveys in the salt flat nucleus have contributed to a better understanding of the layering of the reservoir, its depth, and the influence of the structural features present. Figure 7-1. presents the latest seismic reflection interpretation (AguaEx SPA, 2020), highlighting the ductile deformation of the stratigraphic units due to displacement of the Cabeza de Caballo and Salar faults (eastern portion of the section). Resistivity methods (e.g., TEM and nanoTEM) were undertaken, mainly along the marginal areas of the Salar de Atacama, aiding in delineating the brine-freshwater interface and lithologic changes with depth.

Figure 7-1. Seismic Reflection Survey (AguaEx, 2020)

Note: The lines on the map indicate the seismic profile locations. The red line indicates the location of the profile shown in Figure 7-1..

Table 7-1 summarizes the surface geophysical dataset utilized by SQM. Table 7-2 shows the quantity and length of all downhole logs reviewed by SQM.

Table 7-1. Summary of the Conducted Geophysical Datasets

Table 7-2. Summary of the Conducted Borehole Geophysics

The Salar de Atacama nucleus is densely covered by wells that provide geological, hydrogeological, geophysical and hydrogeochemical data. A total of 2,725 wells (more details in Chapter 11, Table 11-1), covering an approximate total drill length of 164 km, were used to construct the geological conceptual model for the Project. Figure 7-2 shows the well distribution in the OMA Exploration Area of the Salar de Atacama nucleus. The well data is stored and managed by SQM in an acQuire™ database. Tableau™ is used as a front-end process to facilitate the review and analysis of well data held in the acQuire database.

Figure 7-2. Distribution of Wells that provide Geological and Hydrogeological Information for the Project (SQM, 2020)

The total porosity of an earth material is the percentage of its total volume that corresponds to fluid-filled voids. Pumpable brine is hosted in the network of interconnected pores of the geological material that hosts the brine. This interconnected network of drainable, or pumpable, pore space comprises the effective porosity of the material.

The volume of water that will drain naturally under gravity at atmospheric pressure from the effective porosity as a water table descends through the geological medium is termed the drainable porosity or specific yield. The fraction of the water that is retained in the interconnected pore space by capillary forces is termed the specific retention. Isolated (non-connected) pores form a minor part of the total porosity of the system. These pores will not drain under gravity and are non-pumpable.

SQM’s brine volume estimate in the nucleus of the Salar de Atacama is based on over 14,500 porosity measurements in over 100 wells (Table 7-3 and Figure 7-3) evenly distributed across the surface of the salt flat nucleus. Figure 7-4 summarizes the distribution of effective porosity in the Upper Halite, Intermediate Halite, and Halite with Organic Matter units.

Table 7-3. Summary of Boreholes with Porosity Measurements

Figure 7-3. Distribution of Boreholes with Porosity Measurements

Figure 7-4. Effective Porosity (%) Histogram of the Upper Halite, Intermediate Halite, and Halite with Organic Matter

In the Salar de Atacama, SQM’s operational wells are constantly sampled. Wells can also be monitored in areas where production wells are not allowed (OMA Exploration). In all, brine chemistry sampling from wells has been performed using:

Chemical samples are collected under field standards and procedures followed by the SQM field team. In general, the sampling of each chemical record consists of the collection of brine in two plastic bottles, a 125 milliliter (mL) bottle for chemical analysis and a 250 mL bottle for density analysis. A third sample is taken to verify the analysis, or original sample. The analyzed chemical constituents correspond to:

Potassium is analyzed by inductively coupled plasma (ICP) analysis, and Li is analyzed by atomic absorption spectroscopy (AA). During this process, several quality assurance and quality control (QA/QC) standards are followed before and during the analysis (Chapter 8), and then during data reporting.

Figure 7-5 shows the spatial distribution of the utilized brine chemistry measurements. As shown, the brine chemistry distribution is considerably dense and most samples come from pumping wells, increasing the confidence in the brine chemistry distribution and its representativeness of the reservoir chemistry.

Figure 7-5. Distribution of Boreholes with Brine Chemistry Measurements

Figure 7-6 shows the histograms of the brine chemistry dataset for Li and K after filtering the data for potential anomalies and errors. Mean, minimum (min), and maximum (max) concentrations for each analyzed solute are also included (Figure 7-6) from the extensive dataset of nearly 5,000 brine samples.

Figure 7-6. Histogram of Li and K Concentrations (%)

In the Salar de Atacama nucleus, SQM has its own equipment and personnel to carry out hydraulic tests, allowing for relevant information to be continuously generated on the reservoir permeability. All these tests are constantly supervised in the field by SQM's team of geologists and hydrogeologists under standardized procedures that are updated every year.

Transmissivity1 was estimated from two types of hydraulic tests, pumping tests and packer tests. The former tends to be more representative, since they can pump high flow rates (up to 100 L/s, depending on the screened unit), and usually last for four days, or more. Packer tests allow for more representative results of select lithologies (pumping sections between 1.5 m and 9 m). In general, the conducted packer tests are of short duration and lower flow rates (less than 1 L/s for less than 24 hours).

The current hydrogeological conceptual model of the Salar de Atacama considers ten “grouped” hydrogeological units described in Table 7-4. The third column of Table 7-4 indicates the hydraulic character of the unit. HU1, Unit A (UA), is characterized as an unconfined brine unit, while the HU3, Unit B (UB), is characterized as a confined brine system due to massive halite of generally low porosity. In the case of the UB, the hydraulic confinement in certain sectors is due to the overlying aquitard (low permeability layer) of the interbedded halite and gypsum with organic sediments of HU2, Aquitard UAB. Unit UC is confined and comprises thin, but permeable tuffs and interbedded gypsum of low permeability. Unit UD is also confined and is characterized by a low permeability. The other units (UH6 to UH9) correspond to marginal facies along the boundaries of the salt flat nucleus.

The description in the fifth column of Table 7-4 highlights the importance of the structural control and tectonics on the Atacama Basin. Units that exist to east of the Salar Fault (East Block) have a significantly greater thicknesses when compared to the west of the Salar Fault (West Block). The majority of brine extraction wells operated by SQM and Albemarle are located in the West Block.

1 The term transmissivity (T) is used to describe an aquifer’s capacity to transmit water. Transmissivity is equal to the product of the aquifer thickness (m) and hydraulic conductivity (K).

Table 7-4. Hydrogeological Unit Descriptions

For the ten hydrogeological units, Table 7-5 shows the conceptual ranges of hydraulic conductivity (K), a parameter used to measure how easily groundwater can flow through the aquifer. These values are based primarily on the dataset built by SQM over the years from (a) pumping tests and other hydraulic tests conducted by SQM in the set of boreholes that it manages in the Salar de Atacama Basin, particularly the nucleus; and (b), peer-reviewed values published by third parties, or otherwise made available in the public domain, (e.g., within the context of environmental impact assessments of third-party projects). Figure 7-7. Hydraulic Testing Locations, OMA Exploration shows the distribution of the hydraulic tests conducted within the OMA Exploration Area.

Figure 7-7. Hydraulic Testing Locations, OMA Exploration

Table 7-5. Hydraulic Conductivity Ranges for each Hydrogeological Unit

(1)Note: Estimated values based on the lithology

Figure 7-8 and Figure 7-9 present hydrogeological cross sections in the Zona Autorizada de Extracción, or Authorized Extraction Zone (ZAE), with their locations in plan view. The structural control exerted by the faults, particularly by the Salar Fault and the Cabeza de Caballo Fault, are evident.

Figure 7-8. W – E Hydrogeological Cross Section from the Hydrogeological Model

Figure 7-9. SW - NE Hydrogeological Cross Section from the Hydrogeological Model

The Salar de Atacama represents a hydrological discharge zone, where incoming freshwater recharge from high-elevation areas approaches the salt flat margin and discharges to the surface, mainly due to water density differences. Flow directions are predominantly from surrounding high-elevation areas toward the salt flat margin and nucleus, where active evapotranspiration is present.

A conceptual water balance was developed by SRK (2020) and updated by SQM (2021), which considers discharges from different points of the Salar de Atacama basin through three zones to include the upper, middle, and lower zones. In this system, contributions of direct recharge from the upper to middle, and middle to lower zones are mainly dominated by evapotranspiration at the surface. In the lower zone, brine is present and includes the nucleus plus the part of the marginal zone that lies towards the bottom of the interface (called the marginal zone - brine). Recently, lateral recharge was updated by WSP (2022), in order to incorporate new information provided by SQM.

The conceptual water balance considers all main input and output components that are summarized below:

Inputs:

Outputs:

It is the resources QP's opinion that the hydrogeological characterization, hydraulic testing, sampling, and laboratory methods meet the standards for a lithium project and operation of this developmental status. Furthermore, the amount of data obtained from exploration and testing is considerable when compared to other lithium brine projects. It is believed that the characterization of the brine reservoir is at the level of detail needed to support the lithium brine Mineral Resource and Mineral Reserve estimates presented in this TRS.

SQM operates a production wellfield, with discrete vertical wells, that extracts brine largely from massive evaporitic deposits in the Salar de Atacama. Since the mining operation does not involve the excavation of open pits, or underground mine workings, to access the mineral deposit; and because a compact lithology is prevalent in many areas of the Project, it is not necessary to develop a detailed characterization of the geotechnical behavior of the earth materials over the spatial extent of this mining property.

The utilized sampling methods in the Salar de Atacama are related to the different drilling and pumping methodologies performed in the distinct field campaigns. Diamond drilling is used by SQM to obtain core samples for porosity analysis. This method allows for the collection of rock cores from which samples are selected and prepared for analysis. Subsequently, collected brine samples for chemical and density analysis are taken during and after the drilling of each well. The sampling by pumping, drilling (for exploration chemistry), and bailer and packer tests are used for obtaining brine samples from wells. The main ions analyzed, regardless of sampling method, include:

A traceable control system is implemented for the different sampling methods (brine and core), allowing for the monitoring of a sample from collection through to its entry in the database. During each step in the sampling and analytical process, a record of what has been done is documented, and the samples delivered/received follow the procedures and instructions created through a physical document called the “Chain of Custody”.

The QA/QC processes implemented by SQM provide reliability in the precision and accuracy of the data used for the estimation of Mineral Resources; therefore, the precision ranges in the brine sampling of the different operations are defined within the plant. Similarly, the parameters of precision and accuracy are designated in the chemical analysis process of the Analytical Laboratory of the Salar de Atacama (Lab SA), as well as for porosity in the Salar de Atacama Porosity Laboratory (Lab POR).

Samples are collected in 125-mL bottles for chemical analysis and 250-mL bottles for density analysis. They are previously rinsed with the same brine from the well to be monitored, filled to the top, and then sealed and labeled with a code per sample (both bottles have the same code, but refer to different analyses). As the last stage, brine samples are recorded on a control sheet. However, a third sample can be drawn as a “counter sample” (CM) for exploration and pumping test samples, and it is kept for two months. This sample is used to corroborate that the sample collection and analysis was correctly undertaken. Brine samples are sent to the QA/QC laboratory (Lab QA/QC) to centralize the reception activities of the brine samples from all areas, prepare shipments, prepare, and insert quality control samples, and send the samples for chemical and density analysis at the Lab SA.

The wells with effective porosity samples come from diamond exploration campaigns with core recovery. The methodology of sampling and preparation of the samples for the estimation of porosity consists of an internal, rigorous and standardized SQM process, including the determination of the sampling frequency during drilling (currently, one sample every 1 m), the regularization and lithological description of the core sample (established every 10 cm in length), determination of analyzed samples, selection of samples for porosity, lithological description of the sample, labeling of samples (with a unique sample code), and recording of samples in the database.

Before conducting the porosity analysis, the samples go through a documentation review process and are measured to record their mass, diameter, and length. They are then photographed and analyzed.

All samples go through a process that involves both SQM’s Hydrogeology Department (GHS) and Lab SA of the Salar de Atacama Production Management (GPS). The GHS oversees sampling, preparation of dispatch, entry into systems, shipment of samples to laboratory, importing, interpreting, and uploading of the results to the database. The SA Lab is responsible for the analysis of the samples and publication of the results in the system for import. The process of preparing samples for laboratory analysis goes through a treatment that spans the determination of the calibration curve, dissolution of salt precipitates, and weightings until the matrix is prepared for chemical analysis. Each sample is analyzed by different processes. Different equipment is used, depending on the requested analyte. Different matrices are prepared for each sample with different dilutions. Potassium is analyzed by inductively coupled plasma analysis (ICP). Li is analyzed by AA Spectroscopy.

Lab SA and Lab QAQC are internal to support production and are currently not accredited. Nevertheless, SQM completed a round robin analysis for four laboratories, three of which were external laboratories (LSA of the Universidad Católica del Norte, Geo Assay Group, Universidad de Antofagasta Asistencia Técnica S.A.). The evaluation of accuracy was undertaken for the different certified analytes and standards.

Historically, in the Salar de Atacama, different direct methods were used to estimate the porosity of the samples. Since 2011, SQM has used pycnometers to measure the grain volume of rock samples and apparent density. These pycnometers are found in the SQM Porosity Laboratory, located in the Salar de Atacama. Through a double-chamber helium pycnometer (Accupyc), and according to Boyle's Law, the volume of grains in the sample is obtained. The volume of the envelope is calculated using a Geopyc, which determines the volume and density of the rock by displacement of a solid medium of small and rigid spheres with a high degree of fluidity (Dry Flo), wrapping the analyzed object without invading its pores. The Salar de Atacama Porosity Laboratory is internal to support production, and it is currently not accredited.

SQM has implemented standardized protocols for both for the analysis of brine chemistry, as well as for the analysis of effective porosity to ensure good practices when determining both the evolution of brine chemistry and the porosities of the different units present in the Salar.

For brines, a QA/QC program was implemented to maintain an orderly data flow, providing monitoring from sample collection to the entry of the results into the database. Comparisons are made between duplicate and original (primary) samples, taking triplicate samples both in original and duplicate samples. Assays are performed with reference materials to monitor accuracy, and analytical blanks are included to determine potential contamination during sample collection.

In the case of effective porosity analysis, as with brines, there is a QA/QC program that generates standardization throughout the process, including the insertion of control duplicates. In addition, to ensure correct quality control, three stages are implemented for the general process to include calibration of the equipment during the analysis of the samples, validation, and exclusion of data after entering the database in acQuire.

The SQM brine chemistry QA/QC program was created for the implementation of good practices for the utilized protocols. They range from the brine sampling activities to the receipt of samples, dispatch preparation, laboratory analysis, and receipt and review of results.

The systematic inclusion of QC samples is carried out to monitor the precision, accuracy, and potential contamination of analytical processes and conducted sampling. This monitoring is based on the following:

1) Inserting duplicates for precision monitoring:

2) Inserting reference materials (standards or RM’s) for accuracy monitoring:

3) Inserting blanks (BLK) for monitoring potential contamination:

In October 2023, SQM increased the shipment of QC samples once again, aiming to standardize 17.5% of the total samples in the dispatch. Each one of these dispatches consists of 40 samples in total; however, this percentage depends on the sampling behavior with the daily duplicate sampling, as well as the RM and analytical targets inserted in the QA/QC Lab. In addition, a protocol is considered for the insertion of QC samples in the dispatches, for which their location is known in relation to the primary samples.

With the processing of 804 analytical duplicates and 522 field duplicates analyzed at Lab SA, the Max-Min graphs were made for Li and K considering an error ratio (ER) acceptance limit of 10% (SQM, 2020). The errors of Li and K for the analytical and field duplicates are shown in Table 8-1. Figure 8-1 and Figure 8-2 shows the plots for the evaluation of analytical and field duplicates, respectively.

Table 8-1. Evaluation of Analytical and Field Duplicates in Lab SA

*This table includes analytical, and field duplicates up until the end of 2020

Figure 8-1. Error Ratio Plots, Analytical Duplicates.

Figure 8-2. Error Ratio Plots, Field Duplicates.

The conventionally accepted maximum ER is 10%. Therefore, it is concluded that the analytical precision and that of the sampling of the elements evaluated until the end of 2023 in Lab SA were, in practical terms, within acceptable limits, and that the sampling and analysis methods were adequate for the brine samples.

Standards are included in shipments sent to the primary laboratory to evaluate the variability and stability of the RM’s. Control Charts are prepared to check, identify, and exclude any Out-of-Control samples (SOC). 1,900 samples of these RM’s were sent to Lab SA throughout the period for their respective chemical analysis. The standard shipment process consists of daily extraction of the necessary reference material samples, which are placed in 125 mL containers, labeled, and inserted anonymously in the dispatch for analysis at Lab SA.

In 2023, the Bias was assessed through the curve of regression Reduced Major Axis (RMA) between the values reported by Lab SA and the Best Value (BV) for each RM’s, extracted from the Round Robin interlaboratories. For this analysis, 12 standards were prepared and sent to 4 different laboratories each trimester of 2023 (January, April, July, October), of which 3 are external laboratories (LSA of the Universidad Católica del Norte, Geo Assay Goup and Universidad de Antofagasta Asistencia Técnica S.A.) and 1 internal laboratory (Laboratorio Analytical of the Salar de Atacama); Each sample underwent 3 analyzes, and then carried out the determination of the average per standard of each laboratory, with which the Round Robin analysis and determination of BV. The table below summarizes the results for accuracy.

Table 8-2. Summary of Possible Pollution Ratios of Blank Samples during Analysis.

Summary for Accuracy

Figure 8-3. Accuracy Plots, Reference Materials

For 2023, the Li results support Lab SA's excellent performance for accuracy in brine chemical analyses, without presenting issues related to bias, which are below the recommended 10%. The results for K showed values slightly above the recommended 10%.

The insertion of analytical blanks in the shipments sent to the primary laboratory aids in determining if there is any degree of contamination in the laboratory analysis process. The blank is composed only of deionized water and was analyzed in the primary laboratory.

In Table 8-3. Summary of Possible Pollution Ratios of Blank Samples during Analysis.the Possible Pollution Ratios (PPR) for 794 analytical blank results for validated samples, the PPR were low in Li (2.1%), and the K presents rates slightly above 5% (6.9%). These results correspond to the samples after having extracted the errors due to misallocation of labels. K results present rates slightly higher than 5% apparent contamination, which is possibly related to the low precision for very low concentration for K, and not with actual contamination. In general, the results for potassium and lithium do not present contamination problems.

Table 8-3. Summary of Possible Pollution Ratios of Blank Samples during Analysis.

Figure 8-4. Contamination Plots, Blank Samples

QA/QC is implemented in three different stages of the general process, including in the equipment during the analysis of the samples, after entering the results in the database, and through scatter charts for the control and analysis of the precision of the process.

Stage 1: In the equipment during analysis of the samples

The precision of an assay is validated by both instruments (Geopyc and Accupyc), using a range acceptance of the results, where results are guaranteed to be within this range, or the analysis is repeated. Through the software for each instrument, different processes of calibration, and review of their accuracy is undertaken using manufacturer standards.

Stage 2: After entering results in the database

The purpose of this system is to establish parameters for validation and exclusion of samples automatically when entering the data in the acQuire database, leaving these flagged and included/excluded from the dataset for estimation, if applicable. Of the 18,878 total samples registered in the GHS database, 3,019 samples were excluded using QA/QC parameters after data entry into acQuire (16.0% of the total population), resulting in 15,859 validated samples (84.0% of the total population) for the brine volume estimation dataset.

Stage 3: Through scatter charts for the control and analysis of the process precision

This control measure is based on the systematic insertion of duplicate samples (QC) in analysis for porosity that are later analyzed using scatter charts displayed directly in acQuire. For 2023, 3,008 samples were registered in the database for porosity results and have been obtained from 2,838 primary samples and 170 duplicate samples, for 5.7% of controls.

Table 8-4 Table 8-4. Duplicate Sample Evaluation in the Porosity Labshows the duplicate sample evaluation and summarizes the error ration in the porosity lab. Figure 8-5 and Figure 8-6 shows the scatter plots of the pairs analyzed with Accupyc and Geopyc, respectively.

Table 8-4. Duplicate Sample Evaluation in the Porosity Lab

Figure 8-5. Scatter Plot for Pairs Analyzed with Accupyc.

Figure 8-6. Scatter Plot for pairs analyzed with Geopyc

The conventionally accepted maximum ER is 10%. Therefore, it is concluded that the analytical precision of the elements evaluated during this period in the POR Lab was within acceptable limits. Further, the rock sampling method and volume analysis were adequate for the samples of porosity.

In the QP's opinion, sample preparation, sample safety, and analytical procedures used by SQM in the Salar de Atacama follow industry standards with no relevant issues that suggest insufficiency. SQM has detailed procedures that allow for the viable execution of the necessary activities, both in the field and in the laboratory, for an adequate assurance of the results.

Verification by the QP covered field exploration, drilling and hydraulic testing procedures, (including descriptions of drill core and cuttings), laboratory results for effective porosity and chemical analyses, QA/QC results, review of surface and borehole geophysical surveys, and review of the data entry and data storage systems.

Based on the review of SQM’s procedures and standards, it is the QP’s opinion that SQM has data verification standards capable of ensuring good control and quality of the data obtained during drilling as well as from hydraulic and geophysical testing. Based on the review of the QA/QC data during the period, the QP considers the sampling procedures as well as those of preparation and analysis for K and Li in the primary laboratory adequate for the brine and rock samples. Further the QP considers the resulting analytical data to be sufficiently accurate.

There are no limitations on the review, analysis, and verification of the data supporting Mineral Resource estimates within this TRS. It is the opinion of the QP that the geologic, chemical, and hydrogeologic data presented in this TRS are of appropriate quality and meet industry standards of data adequacy for the Mineral Resource and Mineral Reserve estimates.

Since 2021, SQM has used acQuire, a world class geoscientific information management software. This has allowed SQM to centralize data management and avoid the use of data sheets, such as Excel, that can lead to a greater possibility of error. This software implements a series of rules to assure the quality control of data entry, preventing common mistakes, such as out-of-range values, incomplete data, etc.

The QP reviewed the data collection procedures associated with drilling, hydraulic tests, and geophysics surveys. SQM has a set of technical procedures for each of its field activities. These procedures seek to establish a technical and security standard that allow for field data to be optimally obtained while also guaranteeing the safety of workers.

The QP reviewed SQM’s data collection and QC procedures. Regarding the analysis of brines, these procedures are considered adequate. It is evident that they used adequate insertion rates for different controls.

As for porosity tests, the SQM QC protocol considers the analysis of duplicate samples that are repeated adequately for this type of control.

The QP reviewed the error rates of K and Li as well as the rates of analytical duplicates and field duplicates in brines. It was found that they remained within limits conventionally considered acceptable (under 10.0%). Error rates for both Accupyc and Geopyc analyzes for porosity were also within conventional limits and were considered acceptable (under 10.0%).

The QP concludes that the sampling, preparation, and analysis procedures of brine samples as well as rock and analysis of volumes for porosity to be adequate for the evaluated period.

SQM performs a round robin analysis at five laboratories. Four of the laboratories are external (ALS Patagonia S.A., LSA of the Universidad Católica del Norte, Andes Analytical Assay, and the Geo Assay Group). The fifth is an internal laboratory (Analytical Laboratory of the Salar de Atacama). SQM uses these laboratories to evaluate bias for the different certified analytes and standards. Additionally, external control of the results is carried out in the laboratory of the University of Antofagasta (Lab UA).

The QP considers that this evaluation supports the accuracy of the brine chemistry data for the purpose of its use in preparing geological models and estimating Mineral Resources and Mineral Reserves.

During the data review for the period that the samples were evaluated, there was no significant contamination of any of the analytes evaluated for brines during primary laboratory analysis. However, Li results presented rates slightly higher than 5% of apparent contamination. This is possibly related to the elevated content of the targets used and not due to contamination.

It is the QP’s opinion that the analytical results of the geologic, chemical, and hydrogeologic data presented in this TRS are of appropriate quality and are sufficiently reliable to meet industry standards of data adequacy for the Mineral Resource and Mineral Reserve estimates.

This sub-section contains forward-looking information related to recoveries for the Project. The material factors that could cause actual results to differ materially from the conclusions, estimates, designs, forecasts or projections in the forward-looking information include any significant differences from one or more of the material factors or assumptions that were set forth in this sub-section including actual brine characteristics that are different from the historical operations or from samples tested to date, equipment and operational performance that yield different results from the historical operations, and historical and current test work results.

Brine chemistry exploration in the Salar de Atacama was the first step in designing a lithium recovery process, and this was followed by the planning and confirmation of the Project’s operational success. The basis of the process methods was tested and supported by laboratory evaporation as well as historical metallurgical response tests. Since 2015, additional research and projects were implemented to improve yield and recovery, and they have also continuously improved the accuracy of lithium and potassium salt recovery modeling for each of the brine extraction well areas.

Historical test development has allowed for the differentiation of main categories for brine types based on composition and proportion between species. Such tests have been designed to optimize the extraction processes and ensure that customer product specifications are achieved. Furthermore, these tests ensure that deleterious elements remain below the established limits.

Summaries of the analytical and experimental procedures as well as the main test results are presented in the following subsections.

Testing has been conducted to estimate how different brines respond to concentration via solar evaporation and overall metallurgical recoveries from the process plant. Testing also aims to evaluate treatability of the raw material for finished lithium and potassium products. Laboratory tests generate data for the characterization and recovery baselines.

The tests detailed below have the following objectives:

The testing program requires that SQM staff collect brine samples from wells on a regular basis for testing. Sample collection takes place throughout the year with specific campaigns defined in an annual plan. Once each sampling program is completed, the samples are sent to internal labs for chemical analysis. Complementary sampling then considers the temporal, hydrogeological, spatial, and operational criteria of the wells. The chemical concentrations of the wells are also updated. In all, this process generates data that provides accuracy in the estimation of brine chemistry.

It should be noted that SQM's Salar de Atacama brine exploitation system focuses on detecting, differentiating, and segregating brine wells based on their concentration. If the criteria are met, the brine is directed directly into the well system, but if not, it goes into the collector system. This approach helps to prevent dilution of the brine grade by mixing with brines that are lower in potassium and lithium or contain higher levels of magnesium, calcium, boron, and sulfate. The analytical laboratories at Salar de Atacama support this well categorization approach, making the system more efficient in terms of resource utilization and well availability.

The Salar de Atacama laboratories, via its three sub-facilities (Table 10-1), i.e., Laboratory QA/QC, analytical laboratory, and metallurgical laboratory, produce metallurgical test databases which include results for:

The metallurgical tests are designed to estimate the distinct responses of brine and salt when exposed to productive treatment and their also evaluate the most appropriate route for treatability. The internal laboratories oversee support for these operations, providing data from tests to create a database of characterization of feed salts and production performance. For this purpose, samples are collected and subject to chemical and mineralogical analysis.

Historically, SQM has conducted these tests at the plant and/or pilot scale through its research and development department, allowing for (i) an improved recovery process and product quality, (ii) lithium recovery from lithium carnallite, (iii) increased LiOH.H2O production capacity, and (iv) increased Li2CO3 production capacity.

Samples for metallurgical testing are obtained through well sampling, pond sampling, and salt sampling campaigns. Quality Control is implemented at all stages to ensure and verify that the collection process occurs successfully and remains representative. Laboratory facilities available to analyze samples are located at the Salar de Atacama Mine and PQC. In the following subsections, a discussion is provided on brine sampling, preparation, and characterization procedures as well as monitoring activities at the PQC and Salar de Atacama.

Table 10-1. List of Laboratory Facilities Available for Analysis in Salar de Atacama

SQM's new initiatives to improve the recovery of lithium from the LiCl production process are supported by internal laboratories in Salar de Atacama, which carry out chemical analysis of brines and salts. Further information on these initiatives can be found in section 10.4.1.

With regards to the production of lithium carbonate and lithium hydroxide, the Salar del Carmen Laboratory (LSC) in PQC conducts quality control tests on liquid and solid samples, as well as finished products (see Table 10-2).

Table 10-2. List of Installations Available for Analysis at PQC

The following subsections discuss brine sampling, preparation, and characterization procedures, as well as monitoring activities at the PQC and Salar de Atacama.

In the Salar de Atacama, wells involved in the Project’s operation are constantly sampled. Well sampling for brine operations is determined through planning and production management, according to internal requirements.

Samples for the chemical characterization of brine are taken from the wells involved in the Project’s operation, which together with other samples from the database, are used for the evaluation of Mineral Reserves. Brine samples from pumping are collected for chemical and density analysis. These wells are called "Operational", while those wells which are used for exploration are called "Non-operational". The latter are sampled to assist in mine planning for future extraction scheduling. Brine sampling, obtained by pumping a well and enabled in one or more reservoirs, is categorized according to the status of the well, as detailed in Table 10-3.

Table 10-3. Categorization of Brine Samples from Wells

Pumping well sampling and measurements are aimed to reach a maximum dynamic level, take brine samples, and measure basic parameters, such as level, flow, viscosity (Marsh funnel determination), clarity, and presence of fine sediments (by measuring both parameters in an Imhoff cone) as well as temperature, pH, and electric conductivity using a multiparametric probe (Figure 10-1).

Sampling is executed in a plastic jug, directly from the well head (at the pump outlet), by opening a tap placed for that purpose. Before taking the sample, fresh brine is added to the jug in order to remove any residue from a previous sample. This procedure is repeated each time a sample is taken or transferred to sample containers.

The final brine sample is discharged into a receptacle from which samples are drawn for chemical analysis, covering a range of dissolved metals, including lithium and brine density (125 mL for chemical analysis and 250 mL for brine density analysis); after each container is primed and fully filled. Containers for samples are properly identified with self-adhesive labels with barcodes.

Figure 10-1. Determination of In-situ Brine Parameters at Pumping Wells

	a)     Sampling	b)      Clarity and fine sediment measurement
	c)     Viscosity measurement.	d)     pH, temperature, and conductivity measurement

Brines are not exposed to any preparation, or acid preservation, as a pre-treatment before being submitted for chemical analysis at the destination facilities. Brine sampling operation quality control includes taking field duplicates every 15 samples (through repetition of the sampling procedure) and analytical duplicates (by taking a duplicate from the same jar). The operations outlined above are implemented depending on sampling requests and operational capacity.

It must be noted that brine in the salt flat acts as a "mobile resource;" and in some cases, where formation permeability is low, it is not possible to collect a brine sample after a waiting period. For sampling campaigns, some factors that make sampling impossible must be considered, such as the following:

It should also be noted that to obtain more representative samples from the wells, bailer sampling is not performed in operating wells in detention, considering that when the well is no longer operative its chemistry might be stratified. As improvement measures, in disassembled wells samples are taken with stratified bailers, while shutdown wells are turned on and operated until the well volume is renewed three times, before samples are taken.

Internal laboratories involved in brine sampling, analysis, and testing are listed in Table 10-8, and they are also detailed in the following subsections.

This task is carried out by mine operation staff. At the pumping station, samples are regularly taken from the pond outlet to the brine treatment plant, allowing for improved verification, adjustment, and planning. Samples are taken by a device installed in the pond outlet line behind the pumps, allowing 8 ml to be extracted from the lines every 7 minutes to form a brine composite. Chemical composition measurements of this brine feed are described in the following subsection.

Analytical methods for the determination of lithium, potassium, magnesium, and calcium concentrations in solution are applied using Atomic Absorption Spectrometry (AAS) and ICP techniques. The latter analysis is generally used on a broad set of elements (multi-elemental analysis), including the detection of trace metals. The analytes K, SO4 and H3BO3 are analyzed by ICP mass spectrometry. Li is analyzed by AA spectroscopy in conjunction with the determination methodology. Analysis, methodology and the equipment used in the determinations are indicated in Table 10-4.

Sample preparation process for laboratory analysis goes through a treatment that includes calibration curve determination, dissolution of precipitated salts, and weighing to matrix preparation for chemical analysis. Each sample is analyzed by means of different processes and equipment. Depending on the analyte required, different matrices with different dilutions are prepared for each sample.

Protocols used for each sample are documented in relation to materials, equipment, procedures, and control measures. Brine samples collected are analyzed by testing of specially prepared blanks and standards inserted as blind control samples in the analytical chain.

Regarding quality assurance checks of results, the following criteria was established:

Table 10-4. List of Analyses for the Chemical Characterization.

For the determination of brine density, a representative sample is taken by filling a 16-mL plastic vial and placing it in a sampler, where each vial is introduced into a DMA4500 automatic densimeter which registers the density. This measurement is reported through the LIMS laboratory system, which is an integrated data management software, where reports are created.

Quality assurance controls include equipment status checks, analysis of a reagent blank together with the samples, verification of the titrant concentration, and a repeated analysis for a standard together with the set of samples to confirm its value.

The reference methods followed by the in-house laboratories for the determination of certain analytes ensure a certain degree of reliability of the determination methodology and results. The chemical characterization of the samples takes as reference the methods indicated in:

Standard Methods (SM) produced by the American Public Health Association (APHA), the American Water Works Association (AWWA), and the Water Environment Federation (WEF).For precipitated salts in the ponds, the same chemical analysis parameters (Li, K, Na, Ca, Mg, SO4, H3BO3, Cl) are determined according to the methodology described in the Table 10-4, for their characterization and evaluation of the evaporation-concentration process.

Evaporation monitoring represents an important factor in well management and production scheduling; however it is complex due to the extreme conditions faced by solutions, producing potential errors. Therefore, to validate evaporation well data, calculations were conducted using supplementary meteorological parameters collected at stations installed in the Salar de Atacama. Solar radiation, humidity, wind speed, and temperature represent the dominant processes controlling evaporation. Salt composition effects are also considered, so that evaporation is modeled empirically, with consideration ofmagnesium and lithium concentration in the free brine, as well as SQM weather station data on-site.

Evaporation estimates are obtained by correlating water evaporation at a weather station (variable by seasonality) with well area/shape and well activity over a given period. To estimate evaporation, the equations (correlations of J.A. Lukes & G.C. Lukes [1993]) are applied to the wells. Lukes equation (1993) is applied to ponds with brine (free brine height). The equations relate evaporation area and evaporative activity associated with magnesium, sulfate, lithium, and potassium concentration.

As an exercise, according to the operational statistics reviewed, Table 10-5 summarizes the evaporation rate calculated by the production system (with emphasis on lithium and potassium), which are associated by the type of pond in period 2020-2022.

Table 10-5. Mean Annual Evaporation Rates for each Subsystem in the 2020-2023 Period

Currently, QC procedures for the brine production operation and finished products are in place. These procedures include monitoring efforts from input brine characterization to brine sampling and concentration characterization. These QC procedures also apply to products obtained from the MOP, SOP, and lithium chemical processing plants.

In this regard, the involved laboratories support operations to ensure that the system’s treatment requirements are effective.

The operation of solar evaporation wells is based on controlling the chemical balance of the solutions to be extracted and by verifying ion levels that are part of the product (Li, K) as well as the ions which can affect (positively or negatively) their recovery (SO4, Ca, Mg). For this reason, mine programs are focused on obtaining solutions with concentration parameters that meet solar well operational requirements in its two lines to include MOP wells (focused on concentrated lithium solution production) and SOP wells (focused on varieties of potassium production). These requirements are fulfilled through the determination of direct delivery of solutions, or through a mixture of brines with complementary chemical characteristics to produce a mixture that complies with feed specifications (maximum ranges of ion concentration fed to each production line) and well systems.

During brine concentration, sequential salts precipitate in the pond system and are harvested, while others are discarded as impurities. For the lithium-focused system, sodium chloride (NaCl) precipitation occurs followed immediately by potassium chloride (KCl) salts, resulting in a brine that is sent to the solar evaporation ponds to concentrate the solution to ~6% lithium concentration. These ponds are the so-called Lithium System.

Once the pond systems are in operation, sampling and test procedures for evaporation tests are as follows:

Laboratory determination of the brine and salt concentration is then used to perform a material balance of the evaporation and crystallization circuits based on this composition of feed, transfers, harvests, and discards. These results are then used to estimate evaporation rates (and hence salt concentrations) reached at each stage. The following subsection details the estimation of the evaporation rate per concentration pool according to the composition of the brine.

As such, samples taken from each production pond that will feed the solar evaporation ponds are continuously monitored. The solutions from each stage of the ponds are also monitored to ensure efficient operational control.

Concentration control in each of the ponds of the lithium system (MOP) are also maintained within the range established for optimum performance and compliance with production plans.

The Carmen Lithium Chemical Plant aims to refine lithium-rich brines from remaining impurities and also perform lithium carbonate synthesis. A part of the carbonate is then used for the synthesis of lithium hydroxide.

Customer requirements for lithium products require lithium carbonate to be 99.5% pure with a maximum concentration of magnetic particles which is less than 500 ppb, and a maximum concentration of sodium, magnesium, and calcium ≤0.05%. The requirements also specify that lithium hydroxide has maximum trace levels of iron, chromium, copper, and zinc no greater than 1 ppm.

The analyses performed for product QC are related to each of the following purification stages:

Analytical methodologies identify deleterious elements (boron, magnesium, calcium, and sulphate) to establish mechanisms in the operation to keep such elements below acceptable limits and also ensure product quality. Table 10-6 lists the basic set of analyses requested from laboratories as well as the methodologies used in determining solutions and solids.

Table 10-6. List of Requested Analyses for Plant Control

Chemical and physical parameters are evaluated, and the finished product then undergoes strict QC. Methodologies used for determining the chemical and physical parameters are recorded in Table 10-7.

Table 10-7. Analysis of Products (Li2CO3/LiOH)

Salar de Atacama's metallurgical test work program requires that samples are sent to internal laboratories located on-site. Table 10-8 details the name, location, and analysis conducted.

Table 10-8. List of Laboratory Facilities Available for Analysis in Salar de Atacama

The Lab SA is not certified by the International Standards Organization (ISO), but it specializes in chemical analysis of brines and inorganic salts with extensive experience since 1995. It should be noted that none of the three internal laboratory facilities owned by SQM and operated by company personnel are certified by ISO standards.

The Lab QA/QC is in charge of sample custody regarding the reception of brine samples from all areas. The Lab is also in charge of dispatching arrangements, preparation and insertion of QC samples and sending them for chemical analysis to the Lab SA. From there, the Lab QA/QC publishes the results. The QA/QC and traceability control program is detailed in the Section Error! Reference source not found..

The Lab SA services are needed in several areas, including exploration, operation, pumping, and monitoring. Samples arriving undergo a preliminary filtering process to eliminate solid materials that remain in suspension.

The Salar de Atacama laboratories continuously improve their procedures with visits from expert advisors and round robin testing. The interlaboratory comparison seeks to share experiences and results with external laboratories that have similar experience in analysis development and implementation. The purpose of this process is to continuously improve the techniques and procedures employed as well as to detect gaps. Therefore, samples are sent to both SQM's external and independent analytical laboratories which are accredited and/or certified by the ISO:

With interlaboratory comparison, a bias evaluation is conducted for different analytes and certified standards. To provide a measure of accuracy, an external control of the results is in process through the University of Antofagasta laboratory. During round robin tests, no significant contamination of any of the analytes evaluated for the brines was detected during the analysis, demonstrating that.:

At PQC and according to sampling and analysis protocols provided, adequate procedural management in both activities was identified. Staff responsible for executing the procedures are properly instructed, trained, and aware of handling the materials and equipment to be used. The staff relies on clearly defined roles in order to comply with the standards defined for each procedure. This includes prior verifications and reporting in case deficiencies are detected, or irregularities in sampling as well as reporting problems with the samples and equipment.

The characterization approach and sample collection procedures used by the most recent explorations program have demonstrated the sampling methodology and documentation procedures. Metallurgical test development is developed by teams of specialized professionals with extensive experience in mining and metallurgy.

Samples selected for testing and/or assays are taken by qualified laboratory personnel and correspond to areas indicated in the sampling plan along the production chain. The samples used to generate metallurgical data are sufficiently representative to support planning yield estimates and are adequate for the purposes of estimating recovery of raw materials from different processing sectors of the company.

QA/QC measures include written field procedures and checks, such as monitoring, to detect and correct any errors identified in the project during drilling, prospecting, sampling, preparation and testing, data management, or database integrity checks. This ensures that reliable data is used for Resource and Reserve estimates.

SQM applies a protocol that requires the laboratory to receive brine samples from all areas developed in accordance with the campaign, address and arrange the dispatch together with shipment documentation of samples and prepare and insert quality controls to confirm the precision and accuracy of the results. By chemical species analysis, an insertion rate of standard, or standard QA/QC samples, blanks, and duplicates is established. Details are provided in Chapter 8 of this Report.

At Salar de Atacama, the testwork has focused on increasing the quality and optimizing the yield of brine product. The specific objectives include the following:

The Salar de Atacama’s yield enhancement plan includes a set of operational improvement initiatives, project development and scale-up initiatives, as well as new process evaluation initiatives with an objective to recover more lithium from the LiCl production system.

Currently, the following initiatives are underway:

All measures/ initiatives are focused on optimizing the Salar de Atacama's operations to capture brine product which could be lost due to infiltration, impregnation, and precipitation. Each measure occurs at different stages of development according to each case.

A brief description of the experimental procedures and relevant or expected results of the initiatives include:

For lithium recovery from impregnated salts, experimental work was designed using a squeeze platform concept to treat bischofite. In the final stages of concentration, impregnated salts from the well system are placed on an impermeable sloping platform, as the brine has a higher concentration and generates a significant amount of salt.

Figure 10-2 shows the displacement of the impregnated brine through the bischofite salts mounted on a squeeze platform.

Different operating conditions were evaluated to account for the height or slope, water/brine irrigation, and duration of each irrigation cycle. Based on the recovery obtained, the relevant results of the work are:

The first phase of the project was evaluated and developed in 2018 based on laboratory and pilot tests. The results of these tests show that it is technically and economically feasible to recover impregnation. Due to this notion and result of the plant, the company decided to realize platforms with a total area of 320,000 m2 for squeezing of the bischofite salts. Thus, by the end of 2021, five (5) platforms had been implemented and during 2022, two (2) more platforms were implemented. The company plans to build and put into operation two additional platforms to treat bischofite from the MOP-I system by 2023.

Figure 10-2. Improved Treatment Scheme for Bischofite Platforms

According to information provided by the company's Research and Development team, it is estimated that 8,942 tons of LCE will be recovered, which will increase the lithium yield of the production operation by 3.0%.

The salt harvesting initiative is focused on reducing loss due to impregnation and improving impregnated brine recovery in the harvesting process of different subsystems.

However, for the time being, the company is focused on reducing the impregnation of the Halite, Sylvinite and Potassium Carnallite subsystems.

The harvesting process includes four main stages, as highlighted below (Figure 10-3):

Figure 10-3. Improved Treatment Scheme for Harvested Salts

a) Ponds scheme during drying and formation stage.	b) Ponds scheme during trenching and cordoning stage.

c) Ponds scheme during sealeing stage.	d) Mineral stockpiling, final stage of the harvesting process.

Improvements in the harvesting process that will recover more impregnated brine per subsystem are listed below:

Based on all this information, it is estimated that 1,091 tonnes of LCE will be recovered, increasing the lithium yield of the productive operation by 0.4%. The improved harvesting initiative is in the process of being implemented in the 3 subsystems mentioned above. Consequently, the estimation and evaluation of partial impacts will be carried out for each subsystem during its operation. These impact values are expected to be reported in the next update of this report.

Due to the success of Phase 1 of the bischofite platform project as well as the extension to the whole bischofite subsystem, the platforms are also being considered for the potassium carnallite subsystem. The same concept for bischofite platforms is proposed and extrapolated to potassium carnallite salts to minimize impregnation losses. This testwork is focused on brine recovery impregnated in salt harvests, aiming to recover the remaining loss of the improved harvest.

Conceptually, this process is the same of bischofite platforms. After impregnation and the reduction of Potassium Carnalite subsystem, the brine will be recovered in squeeze platforms. The recovered brine at this stage is expected to be dispatched with a 55% yield. With this detail, a recovery of 6,250 tonnes of LCE equivalent is estimated to dispatch, increasing the yield of the operation by 2.1 % for the lithium productive system.

During 2021 and 2022, laboratory and pilot scale tests were developed for carnallite squeezing platforms. The tests have been successfully completed and validated the expected performance. Considering this, the company's plans are to conduct industrial scale testing and platform construction upon completion of the bischofite squeezing system. Work is currently underway on the industrial testing program.

During the evaporation process, different salts precipitate sequentially in the ponds, including lithium sulfate (Li2SO4). One strategy to increase yield is to avoid lithium losses from lithium sulfate precipitation and to purify the sulfate brine by adding a calcium source.

To avoid and/or reduce lithium losses by precipitation as lithium sulfate in the concentration system (solar evaporation), sulfate in the brines is abated with calcium chloride to form the alternative calcium sulfate precipitate. This will lead to increased lithium availability in the concentrated brine.

Of the salts generated 270,000 [tonnes/year] contain precipitated Li2SO4 with a grade of 1.17 %Li. If precipitation of this solid is avoided in the LiCl production line, an estimated 9,100 [tonnes LCE/year] can be recovered. It has been estimated that this strategy can be successfully integrated with a yield of 3.1% for the lithium system.

Using these concepts, a testwork program will be developed using the natural brine and a brine treated with CaCl2. The aim is to obtain a dose of CaCl2 that results in the most efficient and cost-effective removal of sulfate ions. Concentrated brine and precipitated salts in both tests will provide information regarding crystallized salts throughout the different stages of an evaporation process.

The successful results motivated the development of two sulfate abatement lines: 1) Rapid implementation in wells from January 2023 and 2) Development of basic engineering for implementation of the process in plant by 2024.

The processes of obtaining refined lithium products were developed over a long period. Operational experience and constant search for operational improvements has led to testwork with the following objectives:

As such, tests are being developed to increase Li2CO3 and LiOH.H2O production capacity mainly using the proven design of production trains, which allows a rapid upscaling of production capacity. Industrial scale tests are being conducted in this way for each incorporated train to verify and establish a balance between performance and maximum allowable lithium concentration along the production train. This is achieved by reviewing conditions at each stage. The following is a brief example of the verifications made by the operating train incorporated for the carbonate line:

In the same way, controls are checked for conditioning, dosing, and obtained product for the hydroxide line. Samples taken from these trains are subjected to the chemical and physical analyses described above.

The most significant risk considerations regarding brine processing as well as the factors detrimental to recovery, or quality of the obtained product, are the potentially present deleterious elements. Harmful elements, especially magnesium, can impede recoveries, as well as affect product quality and selling prices. Brines can be used to produce battery chemicals, however, produced Li2CO3 can be of poor quality (both the grade and with deleterious elements). Raw material risks factors are insoluble material and carnallite content.

Information has been provided in this report regarding conducted tests to process input and output streams, such as salts and brine, as well as finished potassium and lithium products, for elements such as magnesium and other impurities. This shows the continued attention to improve the operation and obtain the best product, as well as an interest to develop or incorporate a new stage, process, or technology to mitigate the impact of risk factors.

There are other elements that must be removed during brine processing which are deleterious and mainly consist of magnesium, sulfate, and calcium; these are represented by the Mg/Li, Ca/Li, and SO4/Li ratios. Furthermore, elevated carnallite causes elevated magnesium levels in the brine. Having then elevated magnesium causes lower KCl concentrations in the brine, reducing plant efficiency and recovery.

Plant control systems analyze carnallite grades and ensure that they will not affect brine KCl concentration and plant performance. When brines with high magnesium concentrations are used, they can be mixed with lower magnesium brines to keep magnesium levels in the plant feed within acceptable limits.

The current QP, as well as previous QPs responsible for this section, is of the opinion that:

This section contains forward-looking information related to Mineral Resource estimates for the Project. The material factors that could cause actual results to differ materially from the conclusions, estimates, designs, forecasts, or projections in the forward-looking information include any significant differences from one or more of the material factors or assumptions that were set forth in this sub-section including geological and grade interpretations and controls and assumptions and forecasts associated with establishing the prospects for economic extraction.

This section describes the Mineral Resource estimate for Li and K in SQM’s tenements of the Salar de Atacama (OMA properties), which is based on the in-situ brine concentrations in the subsurface and drainable interconnected pore volume. The Mineral Resource was estimated by SQM and was subsequently verified by the QP; although SO4 and B Mineral Resources were previously reported (SQM, 2020), only Li and K Mineral Resources are declared in this TRS given their expected economic viability. The Mineral Resource estimation process can be summarized in four major stages, as shown in Figure 11-1.

Figure 11-1. Mineral Resource Estimate General Flowchart 

The OMA properties in the salt flat nucleus have been characterized by SQM using various methods that include the installation of exploration and production wells, shallow brine sampling, and geophysics. Given the continuity and subhorizontal disposition of the distinct geological units and aquifers which make up the reservoir (supported in part by previous work done in the salt flat with seismic reflection; see Chapter 7), the vertical direction of the drilling perpendicular to the stratigraphic units is optimal for the representation of the main characteristics of the deposit and it is thus emphasized in this analysis.

This sub-section contains forward-looking information related to density and grade for the Project. The material factors that could cause actual results to differ materially from the conclusions, estimates, designs, forecasts or projections in the forward-looking information include any significant differences from one or more of the material factors or assumptions that were set forth in this sub-section including actual in-situ characteristics that are different from the samples collected and tested to date, equipment and operational performance that yield different results from current test work results.

The Mineral Resource was estimated based on the lithology, effective porosity, and concentration distributions within the OMA Extraction Zone limited to the nucleus of the Salar de Atacama. The Mineral Resource was estimated, as discussed below.

Construction of the Geological Model: lithologic information as well as available drillhole geophysics were utilized to generate geologic unit volumes in three dimensions using the software Leapfrog Geo. The geological model was also used as a basis to construct the block model utilized for the Resource Estimate. The total number of wells and boreholes used for the construction of the geological model is summarized in Table 11-1; the total combined drill length corresponds to approximately 164 km.

Table 11-1. Total Number of Wells used for Construction of the Geological Model

Calculation of the Brine Volume: a block model was constructed using the Leapfrog Edge software. The effective porosity of the cell was estimated by ordinary kriging (OK) or by assignment of the geometric mean, depending on the number of measured data points from each geological unit. Only the saturated volume was considered based on the most recent water table elevation. The total number of wells used to calculate the brine volume is summarized in Table 11-2.

Table 11-2. Total Number of Drillholes used to Estimate the Brine Volume.

Interpolation of Brine Concentrations: in the block model, concentrations of the ion of interest were estimated for each cell using ordinary kriging and the Leapfrog Edge software; the estimated ions (in wt.%) for the declared resource include K and Li. Brine density was also estimated by ordinary kriging using the complete dataset and a single estimation domain. The total number of wells used for the brine chemistry estimation is summarized in Table 11-3.

Table 11-3. Total Number of Wells used for the Chemistry Interpolation.

Resource Estimate: Once the block model was built with the reservoir units, porosity, chemistry and brine density, the mass of the chemical element inside of a defined brine volume was estimated using the following formula:

Where:

= Metric ton (tonne) of K or Li in cell i.

= Drainable interconnected pore volume in cell i

= Li or K concentration in cell i (in wt.%).

= density in cell i (in g/cm3)

A block model was defined whose limits and cell sizes are presented in Table 11-4. The total number of cells in the block model is 19,048,848. This block count is necessary to adequately represent vertical variations in concentration and effective porosity.

Table 11-4. Block Model Discretization

*Coordinate System: WGS 84 / UTM Zone 19S In total, the block model covers the OMA Extraction Zone of 81,920 hectares which is designated for the exploration and exploitation of K and Li brines by SQM. A series of cells were conservatively not considered in the estimation domain due to the reasons listed in Table 11-5.

Table 11-5. Conditions and Assumptions for Filtering Cells in the Block Model

The effective porosity (Pe) is defined as the drainable interconnected pore volume of the aquifer material (Hains, D. H., 2012). SQM uses this parameter instead of specific yield to estimate the brine volume due to the measurement techniques of their porosity laboratory (Gas Displacement Pycnometer). Although specific yield was not used for the estimate, the QP considers that the high frequency sampling of Pe, large dataset, and general lack of fine-grained sediments in the subsurface OMA Zone such as clay2 (where specific retention can be dominant) permits Pe to be a reasonable parameter for the Resource Estimate.

Methodology and Estimation of Effective Porosity (Pe)

For the brine volume estimate, two separate methodologies were used according to the characteristics of each geological unit as well the representativeness of the effective porosity data. The utilized methodologies include:

Based on the characterization above, the validated dataset was selected under a series of restrictions according to the lithologies of each geological unit and acceptable porosity values (e.g., positive values, no duplicates, and non-overlapping values). The final dataset with these restrictions applied for the brine volume estimate corresponds to 10,395 samples.

Furthermore, the sample data collected by SQM is complemented by two external studies in the salt flat: Hydrotechnica (1987) and Water Management Consultants (1993). These studies were considered to improve the data distribution along the whole exploration area.

2 Fine-grained sediments are principally found on the surface of the geological model and present a low thickness (1 m average). Additionally, the regional clay unit is found below the base of the resource block model.

Exploratory Data Analysis - Pe

To increase confidence in the resource estimation, an exploratory data analysis (EDA) stage was first undertaken to identify effective porosity trends as a function of the geological units. The EDA of the effective porosity involved the univariate statistics of the samples using histogram, box plots and probability plots. Figure 7-4 shows the statistics of the effective porosity data considered to interpolate UG the Upper Halite, Intermediate Halite, and Halite with Organic Matter units; 9,512 data points were considered, and the x-axes are presented in %.

From analysis of the data, the distributions of the Upper Halite and Intermediate Halite can be summarized as follows:

Due to low data counts for the Evaporitic and Volcanoclastic Unit and Lower Halite Unit, assigned effective porosity values were applied. The assigned values of the effective porosity for the Evaporitic and Volcanoclastic Unit and Lower Halite Unit are presented in Table 11-6:

Table 11-6. Summary of Assigned Pe Values

Table 11-7 summarizes the distinct effective porosity domains and each estimation method employed.

Table 11-7. Effective Porosity Estimation Domains, Brine Volume Estimate

Note: *Not used to as an effective porosity domain for the interpolation of values

Variography and Pe Estimation

The validated dataset was compared with the geological units (GU) and Pe domains. A spatial continuity analysis is made for every estimation unit in the XY plane and in the perpendicular (z) direction, defining the variogram models and search radius used for the interpolations. The effective porosity shows an important horizontal anisotropy and exhibits continuities in the XY plane several orders of magnitude higher than the vertical direction. The variograms of the estimation domains with the most samples (estimation domains #1 and #3) are presented in Figure 11-2 and Figure 11-3. Additionally, the search radius and variogram parameters for the effective porosity estimate are summarized in Table 11-8 and Table 11-9.

Figure 11-2. Variograms of Effective Porosity Domain 1 (Upper Halite).

Figure 11-3. Variograms of Effective Porosity Domain 3 (Intermediate Halite).

Table 11-8. Search Radius Parameters, Effective Porosity Estimate (SQM, 2021a)