Item 2. PROPERTIES

Mountain Pass

The Company owns and operates the Mountain Pass Rare Earth Mine and Processing Facility (previously defined as “Mountain Pass”), which is located on 2,232 fee simple acres of land, approximately 50 miles southwest of Las Vegas, Nevada, near Mountain Pass, San Bernardino County, California, at geographic coordinates 35°28’56”N latitude and 115°31’54”W longitude. Mountain Pass supports the Company’s Materials segment and includes an open-pit mine in the production stage, infrastructure supporting mining and processing operations, overburden and ore stockpiles, a crusher, a mill/flotation plant, hydrometallurgy facilities, separation plants, product finishing facilities, tailings processing and storage facilities, a water treatment plant, an idle chlor-alkali facility, and on-site evaporation ponds, as well as laboratory facilities to support product analysis and research and development activities, offices, maintenance shops, warehouses and support buildings. In 2023, the Company completed recommissioning activities on its previously idle separation facilities at Mountain Pass and completed construction of new assets, which are utilized to separate rare earth concentrate into other products, including NdPr oxide. The Mountain Pass facilities and infrastructure, the majority of which were constructed between 2012 and 2023, are in good operating condition and benefit from routine maintenance. The net carrying amount of property, plant and equipment (excluding mineral rights) used in the operation of Mountain Pass was approximately $621 million as of December 31, 2024.

Mountain Pass directly abuts Interstate 15 and may be accessed by existing hard-surface roads. Water at Mountain Pass is supplied through active water wells, pit dewatering, and process water recovery. MP Materials’ facilities at Mountain Pass are powered by a natural gas-powered CHP plant, which produces electricity and steam, minimizing reliance on the regional electric power grid.

As of December 31, 2024, approximately 1,128 acres of the 2,232 acres were in use (e.g., existing buildings, infrastructure or active disturbance). Portions of the fee lands, none of which are actively being mined or are currently anticipated to be mined for the purpose of recovering ore, are subject to mineral reservations in favor of the U.S. for some properties and the State of California for other properties. The specific minerals reserved on those parcels vary according to the type of land patent or conveyance document through which the land was acquired or conveyed. The Company also owns mining and mill site claims over a further 15,000 acres of adjacent land. The lands surrounding Mountain Pass are mostly public lands managed by the Bureau of Land Management and the National Park Service. In addition, MP Materials holds 525 unpatented lode and mineral mining claims and mill sites under the provisions of The Mining Law of 1872. These mining claims and mill sites provide land for mining, ancillary facilities, and expansion capacity around Mountain Pass.

Mountain Pass represents the largest commercial source of rare earth materials in the Western hemisphere. Molybdenum Corporation of America began REE mining operations at Mountain Pass in 1952. Mining, milling, and separation processes continued under Unocal Corporation, which purchased Molybdenum Corporation of America in 1977, until 1998. In 2005, ChevronTexaco Corporation acquired Unocal Corporation and then, in 2008, Molycorp Minerals, LLC acquired Mountain Pass from Chevron Mining Inc. Operations relating to mining, milling and separations resumed under Molycorp until they were placed into cold-idle status in mid-2015. In July 2017, the Company acquired Mountain Pass from the Molycorp estate.

The Company holds the necessary permits to operate Mountain Pass, including conditional use and minor use permits from San Bernardino County, California, and an associated environmental impact report, all of which were issued in 2004, which currently allow continued operation of Mountain Pass through 2042, though the Company expects to extend such permits to allow for continued operation through at least 2053. Since restarting operations at the facility in the fourth quarter of 2017, the Company’s activities initially focused on the milling and flotation processes, leading to production of a bastnaesite concentrate, rich in REE, with the first concentrate sales in the first quarter of 2018. In the second half of 2023, the Company commenced production of separated rare earth products.

The bastnaesite ore body at Mountain Pass has been mined as a principal source of REE for a period of over 60 years. The Mountain Pass REE deposit is located within an uplifted block of Precambrian metamorphic and igneous rocks that are bounded to the south and east by basin-fill deposits in California’s Ivanpah Valley. The two main groups of rocks in the Mountain Pass area are Early Proterozoic high-grade metamorphic rocks and Middle Proterozoic ultrapotassic rocks and monazitic carbonatites, which carbonatites are associated with higher levels of REE. The total orebody strike length is approximately 2,750 feet and dip extent is 3,000 feet; true thickness of the more than 2% total rare earth oxide (“TREO”) grade

zone ranges between 15 feet and 250 feet. The percentage of each rare earth material contained in typical Mountain Pass bastnaesite concentrate is estimated to be as follows:

			Estimated Distribution of TREO Content
Element
Cerium			50.2		%
Lanthanum			32.3		%
Neodymium-Praseodymium			15.7		%
SEG+(1)			1.8		%

(1)See the “Rare Earth Resources and Reserves” section below for definition.

Independence Facility

The Company owns approximately 18 acres of land in Fort Worth, Texas, on which it is developing Independence, a metal, alloy, and magnet manufacturing facility as part of its Stage III strategy. The building and building improvements were substantially completed in the fourth quarter of 2023. In the fourth quarter of 2024, the Company commissioned machinery and equipment used in the manufacturing of NdPr metal, including electrolysis cells, and placed into service certain other machinery and equipment necessary for the production of other magnetic precursor products, such as strip casters. Installation and construction related to certain magnet manufacturing processes and equipment continues within the building. The Independence Facility supports the Magnetics segment.

Corporate Office

The Company has a lease for corporate office space at 1700 S. Pavilion Center Drive, Suite 800, Las Vegas, Nevada 89135. The lease has an initial term of 91 months expiring in October 2030, with an option to renew for one five-year period at the Company’s election.

Rare Earth Resources and Reserves

Introduction

Mineral resources and mineral reserves were estimated by SRK Consulting (U.S.) Inc. (“SRK”) for inclusion in this Annual Report. Pursuant to the requirements of Regulation S-K Subpart 1300 (“S-K 1300”), SRK prepared a pre-feasibility level Technical Report Summary for Mountain Pass with an effective date of October 1, 2024 (the “2024 TRS”) (refer to Exhibit 96.1 to this Annual Report). The mineral resource and mineral reserve estimated in the 2024 TRS were subsequently depleted by SRK to present an estimate of our resources and reserves as of December 31, 2024. The depletion removed by SRK represents resources and reserves that were extracted from the Mountain Pass open pit from October 1, 2024, through December 31, 2024.

Mineral Resource and Mineral Reserve Definitions

Mineral Resources

Item 1300 of S-K 1300 defines a “mineral resource” as a concentration or occurrence of material of economic interest in or on the Earth’s crust in such form, grade or quality, and quantity that there are reasonable prospects for economic extraction. A mineral resource is a reasonable estimate of mineralization, taking into account relevant factors such as cut-off grade (“COG”), likely mining dimensions, location or continuity, that, with the assumed and justifiable technical and economic conditions, is likely to, in whole or in part, become economically extractable. It is not merely an inventory of all mineralization drilled or sampled.

A “measured mineral resource” is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of conclusive geological evidence and sampling. The level of geological certainty associated with a measured mineral resource is sufficient to allow a qualified person to apply modifying factors, as defined in this section, in sufficient detail to support detailed mine planning and final evaluation of the economic viability of the deposit. Because a measured mineral resource has a higher level of confidence than the level of confidence of either an indicated mineral resource or an inferred mineral resource, a measured mineral resource may be converted to a proven mineral reserve or to a probable mineral reserve.

An “indicated mineral resource” is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of adequate geological evidence and sampling. The level of geological certainty associated with an indicated mineral resource is sufficient to allow a qualified person to apply modifying factors in sufficient detail to support mine planning and evaluation of the economic viability of the deposit. Because an indicated mineral resource has a lower level of confidence than the level of confidence of a measured mineral resource, an indicated mineral resource may only be converted to a probable mineral reserve.

An “inferred mineral resource” is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of limited geological evidence and sampling. The level of geological uncertainty associated with an inferred mineral resource is too high to apply relevant technical and economic factors likely to influence the prospects of economic extraction in a manner useful for evaluation of economic viability. Because an inferred mineral resource has the lowest level of geological confidence of all mineral resources, which prevents the application of the modifying factors in a manner useful for evaluation of economic viability, an inferred mineral resource may not be considered when assessing the economic viability of a mining project and may not be converted to a mineral reserve.

Mineral Reserves

Item 1300 of S-K 1300 defines a “mineral reserve” as an estimate of tonnage and grade or quality of indicated and measured mineral resources that, in the opinion of the qualified person, can be the basis of an economically viable project. More specifically, it is the economically mineable part of a measured or indicated mineral resource, which includes diluting materials and allowances for losses that may occur when the material is mined or extracted. A “proven mineral reserve” is the economically mineable part of a measured mineral resource and can only result from conversion of a measured mineral resource. A “probable mineral reserve” is the economically mineable part of an indicated and, in some cases, a measured mineral resource.

Estimation Methodology

Mineral Resources

The mineral resource estimate has been constrained by a geological model considering relevant rock types, structure, and mineralization envelopes as defined by TREO content within relevant geological features. This geological model is informed principally by diamond core drilling and multiple phases of geological mapping. Sectional interpretation based on the combination of these data were used to influence implicit modeling of the geological data with manual controls where appropriate. Data has been composited to reasonable lengths based on the original sample lengths and expected mining unit scale, and outliers have been addressed during estimation using restrictions on influence.

A number of internal controls have been applied over the history of the Mountain Pass deposit to demonstrate the consistency and reliability of historical analytical data supporting mineral resource estimation. Almost all data supporting the mineral resource has been generated by an iteration of a site-based laboratory at the Mountain Pass mine. The Mountain Pass laboratory uses various quality assurance and quality control (“QA/QC”) measures to calibrate modern equipment and ensure analytical precision and accuracy. QA/QC generated by previous laboratories has undergone check assays at independent third-party laboratories, and generally demonstrate no consistent bias. The quality analytical database is also supported by a limited amount of blind quality control samples inserted during a re-assay program, including site-specific standards of known TREO content, a variety of duplicate samples, and blank samples. The implementation and results of these various QA/QC programs have not been fully aligned with current industry standards and are not comprehensive but are considered satisfactory for use in mineral resource estimation.

Estimates have been validated to the input data using statistical and visual comparisons, localized swath plot comparisons of mean grades, and review of the limited mine production reconciliation data to the model. In general, estimates of grade quality are shown to align closely with the input exploration data, but have been demonstrated to be under-reporting relative to the grade control drilling. SRK has categorized uncertainty and risk at Mountain Pass by classifying the contained mineral resource by varying degrees of confidence in the estimate. The mineral resources at the Mountain Pass deposit have been classified in accordance with S-K 1300 definitions. The classification parameters are defined by the distance to composited data, the number of drillholes used to inform estimated block grades and a geostatistical indicator of relative estimation quality (kriging efficiency). As an overall modifier to classification, SRK considered the results from the QA/QC noted above and the observed variability in production reconciliation in the mineral resource classification as well, both of which preclude the assignment of measured resources, as defined by the SEC. Bulk density is based on average density measurements collected from the various rock types over the years, and carbonatite density in particular is supported by extensive mining and processing experience with the materials.

An economic COG of 2.35% TREO has been developed to ensure that material reported as a mineral resource can satisfy the definition of having reasonable prospects for economic extraction as required for the SEC definition. Mineral resources have been constrained within an optimized economic pit shell based on reserve input parameters, with the exception of the assumed REO selling prices, which are set 15% higher than the reserves price.

For mineral resources, a revenue factor of 1.0 is selected which corresponds to a break-even pit shell volume. SRK notes that the pit selected for mineral resources has been influenced by setbacks relative to critical infrastructure such as the tailing storage and the mill and flotation facilities.

A description of the methodology used to calculate mineral resources is provided in Exhibit 96.1 to this Annual Report.

Mineral Reserves

SRK developed a life-of-mine (“LoM”) plan for the Mountain Pass operation in support of mineral reserves. The Company operates a separations facility at Mountain Pass that allows it to separate bastnaesite concentrate into four individual REO products for sale. The Company further expects to install an ore sorting (pre-concentration) facility during 2025 to upgrade mined ore that is in the 2.5% to 5.0% TREO grade range. The Company expects that the separations and ore sorting facilities will both achieve full design capacity during 2026.

For economic modeling of the mineral reserves, SRK assumed that production will be a combination of bastnaesite concentrate sales and sales of four individual REO products: neodymium and praseodymium (previously defined as “NdPr”) oxide; samarium, europium, and gadolinium (“SEG+”) precipitate; lanthanum carbonate; and cerium chloride. Forecast economic parameters are based on historical cost performance for process, transportation, and administrative costs, as well as a first principles estimation of future mining costs. Forecast revenue from concentrate sales and individual separated product sales is based on a preliminary market study commissioned by the Company.

Pit optimization was performed based on prices that were established by the preliminary market study. The results of pit optimization guided the design and scheduling of the ultimate pit. SRK generated a cash flow model which indicated positive economics for the 30-year LoM plan, which provides the basis for the reserves. Reserves within the new ultimate pit are sequenced for approximately 25 years (Q4 2024 through 2048), with processing of stockpile material to occur for a further approximately 5 years (2049 through early 2053).

The costs used for pit optimization include estimated mining, processing, sustaining capital, transportation, and administrative costs, including an allocation of corporate costs. Processing and SG&A costs used for pit optimization were based on historical actual costs.

Processing recovery for concentrate is variable based on a mathematical relationship to estimate overall TREO recovery versus ore grade. The calculated COG for the reserves is 2.50% TREO, which was applied to indicated blocks contained within an ultimate pit, the design of which was guided by economic pit optimization.

The optimized pit shell selected to guide final pit design was based on a combination of the revenue factor (“RF”) 0.45 pit (used on the north half of the deposit) and the RF 1.00 pit shell (used on the south half of the deposit). The inter-ramp pit slopes used for the mineral reserves pit design are based on geotechnical studies and range from 44° to 47°.

Measured resources in stockpiles were converted to proven reserves. Indicated pit resources were converted to probable reserves by applying the appropriate modifying factors to potential mining pit shapes created during the mine design process. Inferred resources present within the LoM pit are treated as waste. Internal controls to demonstrate the consistency and reliability of the historic analytical data supporting the mineral resource estimate (which forms the basis for the mineral reserve estimate) are discussed above.

A description of the methodology used to calculate mineral reserves is provided in Exhibit 96.1 to this Annual Report.

Results

Mineral Resources

As of December 31, 2024, SRK estimates total indicated resources of 4.35 million STs with an average grade of 3.71% TREO and 13.35 million STs of inferred resources with an average grade of 4.79% TREO. Mineral resources are reported exclusive of mineral reserves. The reference point for mineral resources is in situ material.

Category			Resource Type			Cut-Off TREO (%)			Mass			Average Value
Million Short Tons (dry)			TREO**(1)** (%)			La2O3(2) (%)			CeO2(2) (%)			Pr6O11(2) (%)			Nd2O3(2) (%)			Sm2O3(2) (%)
Indicated			Within the Reserve Pit			2.35			0.73			2.43			0.79			1.21			0.10			0.29			0.02
Within the Resource Pit			2.35			3.62			3.97			1.29			1.98			0.17			0.48			0.04
Total Indicated						2.35			4.35			3.71			1.21			1.85			0.16			0.45			0.03
Inferred			Within the Reserve Pit			2.35			6.85			5.77			1.88			2.88			0.24			0.70			0.05
Within the Resource Pit			2.35			6.50			3.76			1.23			1.88			0.16			0.46			0.03
Total Inferred						2.35			13.35			4.79			1.56			2.39			0.21			0.58			0.04

(1)TREO% represents the total of individually assayed light rare earth oxides on a 99.7% basis of total contained TREO, based on the historical site analyses.

(2)Percentage of individual light rare earth oxides are based on the average ratios; La2O3 is calculated at a ratio of 32.6% grade of TREO% equivalent estimated grade, CeO2 is calculated at a ratio of 49.9% of TREO% equivalent estimated grade, Pr6O11 is calculated at a ratio of 4.3% of TREO% equivalent estimated grade, Nd2O3 is calculated at a ratio of 12.1% of TREO% equivalent estimated grade, and Sm2O3 is calculated at a ratio of 0.9% of TREO% equivalent estimated grade. The sum of light rare earths averages 99.7%; the additional 0.3% cannot be accounted for based on the analyses available to date and has been discounted from this resource statement.

General Notes:

• Mineral resources are reported exclusive of mineral reserves.

• 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 resources estimated will be converted into the mineral reserves estimate.

• Mineral resource tonnage and contained metal have been rounded to reflect the accuracy of the estimate, any apparent rounding errors are considered insignificant.

*•*The mineral resource model has been depleted for historical mining based on the December 31, 2024, pit topography.

• Pit optimization is based on pit slope angles of 39° to 45° including ramps and the following assumed prices: Rare Earth Mineral Concentrate $11.73 per kilogram (“kg”), PrNd Oxide $143.55/kg, SEG+ Precipitate $55.45/kg, La Carbonate $1.66/kg and Ce Chloride $2.96/kg.

• Pit optimization is based on concentrator recovery that varies based on the grade of the ore fed to the concentrator. The average REO distribution in the concentrate is PrNd (15.7%), SEG+ (1.8%), Lanthanum (32.3%) and Cerium (50.2%). Overall recoveries at the onsite separations plant as applied to concentrate containing on average 60% TREO are: PrNd Oxide (89.7%), SEG+ Precipitate (97.9%), La Carbonate (75.0%) and Ce Chloride (11.5%).

• Pit optimization is based on the following costs: mining cost at the pit exit of $1.50 per ST mined plus $0.05 per ST mined for each 15 feet bench above or below the pit exit, sorted ore rehandling ($2.55 per ST of sorted ore mined); non-sorted ore rehandling ($2.17 per ST of non-sorted ore mined), crushing ($3.66 per ST of ore crushed); ore sorting ($1.80 per ST ore fed to ore sorters), concentrating ($50.05 per ST of ore fed to concentrator), general and administrative ($28.82 per ST of ore fed to the concentrator), separations (includes a fixed annual cost and a variable cost of $1,080.59 per ST of concentrate processed on site), finished product shipping ($146.92 per ST shipped) and sustaining capital ($33.23 per ST of ore fed to the concentrator).

• The mineral resource statement reported herein only includes the REE cerium, lanthanum, neodymium, praseodymium, and samarium (often referred to as LREE). While other REE, often referred to as HREE, are present in the deposit, they are not accounted for in this estimate due to historic data limitations.

The following table is provided to show the change in mineral resources from December 31, 2023, to December 31, 2024:

Description			Estimate Date			Cut-off TREO (%)			Million Short Tons (dry)			TREO			La2O****3			CeO****2			Pr6O****11			Nd2O****3			Sm2O****3
(%)			(%)			(%)			(%)			(%)			(%)
Indicated Mineral Resources			December 31, 2024			2.35			4.35			3.71			1.21			1.85			0.16			0.45			0.03
Indicated Mineral Resources			December 31, 2023			2.18			1.45			2.75			0.89			1.37			0.12			0.33			0.02
Difference									2.90			0.96			0.32			0.48			0.04			0.12			0.01
% Difference**(1)**									200.1		%	34.9		%	36.0		%	35.0		%	33.3		%	36.4		%	50.0		%
Inferred Mineral Resources			December 31, 2024			2.35			13.35			4.79			1.56			2.39			0.21			0.58			0.04
Inferred Mineral Resources			December 31, 2023			2.18			9.09			5.05			1.65			2.52			0.21			0.61			0.04
Difference									4.26			(0.26)			(0.09)			(0.13)			0.00			(0.03)			0.00
% Difference**(1)**									46.9		%	(5.1)%			(5.5)%			(5.2)%			—%			(4.9)%			—%

(1)Percentages may not recompute as presented due to rounding.

The difference as compared to the previous year is due to inferred resources located within the mineral reserve pit that were mined and processed during 2024, assumed improvements in metallurgical recovery, and a change in the mineral resource COG due to updated project economics.

Mineral Reserves

As of December 31, 2024, SRK estimates total proven reserves of 0.81 million STs of ore with an average grade of 4.06% TREO and 28.88 million STs of probable reserves with an average ore grade of 6.02%. The Company’s total proven and probable reserves are estimated as 29.69 million STs with an average grade of 5.97%. The reference point for the mineral reserves is material delivered to the Mountain Pass crushing facility.

Based on these estimated reserves, the Company’s expected remaining mine life as of December 31, 2024, is approximately 29 years (2025 through 2053) to complete the processing of stockpiles and separations.

The following table states the amount of the Company’s proven and probable mineral reserves as of December 31, 2024.

Category			Description			Run-of-Mine			TREO%			MY%			Concentrate
Million Short Tons (dry)			Million Short Tons (dry)
Proven			Current Stockpiles			0.81			4.06			4.15			0.03
In situ			—			—			—			—
Proven Totals			0.81			4.06			4.15			0.03
Probable			Current Stockpiles			—			—			—			—
In situ			28.88			6.02			6.96			2.01
Probable Totals			28.88			6.02			6.96			2.01
Proven + Probable			Current Stockpiles			0.81			4.06			4.15			0.03
In situ			28.88			6.02			6.96			2.01
Proven + Probable Totals			29.69			5.97			6.88			2.04

General Notes:

• Reserves stated as contained within an economically mineable open pit design stated above a 2.50% TREO COG.

• Mineral reserves tonnage and contained metal have been rounded to reflect the accuracy of the estimate, and numbers may not add due to rounding.

• MY% (mass yield) calculation is based on 60% concentrate grade of the product and the ore grade dependent metallurgical recovery. MY% = (TREO% * Met recovery)/60% concentrate TREO grade.

• Indicated mineral resources have been converted to probable reserves. Measured mineral resources have been converted to proven reserves.

• Reserves are diluted at the contact of the 2% TREO geological model triangulation (further to dilution inherent to the resource model and assume selective mining unit of 15 feet x 15 feet x 30 feet).

• Mineral reserves tonnage and grade are reported as diluted.

• Pit optimization is based on pit slope angles of 39° to 45° including ramps and the following assumed prices: Rare Earth Mineral Concentrate $10.20/kg, PrNd Oxide $124.83/kg, SEG+ Precipitate $48.22/kg, La Carbonate $1.44/kg and Ce Chloride $2.57/kg.

• Pit optimization is based on concentrator recovery that varies based on the grade of the ore fed to the concentrator. The average REO distribution in the concentrate is PrNd (15.7%), SEG+ (1.8%), Lanthanum (32.3%) and Cerium (50.2%). Overall recoveries at the onsite separations plant as applied to concentrate containing on average 60% TREO are: PrNd Oxide (89.7%), SEG+ Precipitate (97.9%), La Carbonate (75.0%) and Ce Chloride (11.5%).

• Pit optimization is based on the following costs: mining cost at the pit exit of $1.50 per ST mined plus $0.05 per ST mined for each 15 feet bench above or below the pit exit, sorted ore rehandling ($2.55 per ST of sorted ore mined); non-sorted ore rehandling ($2.17 per ST of non-sorted ore mined), crushing ($3.66 per ST of ore crushed); ore sorting ($1.80 per ST ore fed to ore sorters), concentrating ($50.05 per ST of ore fed to concentrator), general and administrative ($28.82 per ST of ore fed to the concentrator), separations (includes a fixed annual cost and a variable cost of $1,080.59 per ST of concentrate processed on site), finished product shipping ($146.92 per ST shipped) and sustaining capital ($33.23 per ST of ore fed to the concentrator).

• Reserves contain material inside and outside permitted mining but within mineral lease.

• Reserves assume 100% mining recovery.

• The strip ratio for the remaining reserves is 5.8 to 1 (waste to ore ratio).

• The mineral reserves were estimated by SRK.

The following table is provided to show the change in reserves from December 31, 2023, to December 31, 2024:

Description			Estimate Date			Run-of-Mine			TREO%			MY%			Concentrate
Million Short Tons (dry)			Million Short Tons (dry)
Proven + Probable Reserves			December 31, 2024			29.69			5.97			6.88			2.04
Proven + Probable Reserves			December 31, 2023			28.46			6.20			6.54			1.86
Difference						1.23			(0.23)			0.34			0.18
% Difference**(1)**						4.3%			(3.7)%			5.2%			9.8%

(1)Percentages may not recompute as presented due to rounding.

The primary reasons for the differences between the two reserves estimates are:

• The reserves were depleted by mining and processing that occurred during 2024. It is noted that reserves depletion due to mining and processing during 2024 was partially offset by additional above COG material that was identified by closely spaced blasthole sampling. This above COG material was not included in the previous reserves estimate because the material had not been identified by the wider spaced resource drilling that informed the resource block model utilized for the 2023 TRS.

• For the 2024 end-of-year reserves, it has been assumed that pre-concentration (ore sorting) will be applied to mined material having an in-situ grade that is in the 2.5% to 5.0% TREO grade range. As a result of pre-concentration, the average grade will be increased for the fraction of sorted material that is advanced to the concentrator. This grade uplift, which is supported by the results of test work performed during 2023 and 2024 on Mountain Pass ores, is expected to allow for improved recovery because metallurgical recovery at the concentrator is positively correlated with feed grade.

• For the 2024 end-of-year reserves, it also has been assumed that overall metallurgical recovery at the concentrator will improve due to the installation of a boiler that has enabled flotation to be conducted at a constant higher temperature, as well as new reagent testing and blending of historically problematic ores. The overall improvements in metallurgical recovery are supported by a plant monitoring campaign that was conducted to evaluate concentrator performance during July and August of 2024.

Factors and Assumptions Affecting Mineral Resource and Mineral Reserve Estimates

There are numerous uncertainties inherent in estimating quantities and qualities of REO reserves and costs to mine recoverable reserves, including many factors beyond our control. We will regularly evaluate our REO reserve estimates. This may be done in conjunction with additional exploration drilling programs. The estimates of REO reserves as to both quantity and quality will also be updated to reflect new drilling or other data received. Estimates of economically recoverable REO

reserves, however, necessarily depend upon a number of variable factors and assumptions, all of which may vary considerably from actual results, such as:

• geological, mining and processing conditions and/or effects from prior mining that may not be fully identified by available data or that may differ from experience;

• the strategic approach to mining and processing the deposit may change depending upon market demand, corporate strategy and other prevailing economic conditions;

• assumptions concerning future prices of rare earth products, foreign exchange rates, process recovery rates, transportation costs, operating costs, capital costs, and reclamation costs; and

• assumptions concerning future effects of regulation, including the issuance of required permits and taxes by governmental agencies and foreign government policy relating to import or export of rare earth products.

Actual REO tonnage recovered from identified REO reserves and revenues and expenditures with respect to the same may vary materially from estimates. Further, period-to-period, our future estimates of REO reserves may fluctuate significantly as macroeconomic conditions and our level of understanding with respect to the deposit change. These estimates may not accurately reflect our actual REO reserves. Any inaccuracy in our estimates related to our REO reserves could result in lower-than-expected revenues and higher-than-expected costs.