Exhibit 96.1

SEC Technical Report Summary

Pre-Feasibility Study

Mountain Pass Mine

San Bernardino County, California

Effective Date: September 30, 2021

Report Date: February 16, 2022

Report Prepared for

MP Materials Corp.

67750 Bailey Road

HC1 Box 224

Mountain Pass, CA 92366

Report Prepared by

SRK Consulting (U.S.), Inc.

1125 Seventeenth Street, Suite 600

Denver, CO 80202

SRK Project Number: 536900.070

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 2

Table of Contents

1   Executive Summary	18
1.1  Property Description and Ownership	18
1.2  Geology and Mineralization	18
1.3  Status of Exploration, Development and Operations	19
1.4  Mineral Processing and Metallurgical Testing	19
1.4.1  Existing Crushing and Concentrating Operations	19
1.4.2  Rare Earths Separations	20
1.5  Mineral Resource Estimate	21
1.6  Mineral Reserve Estimate	22
1.7  Mining Methods	25
1.8  Recovery Methods	26
1.8.1  Existing Crushing and Concentrating Operations	26
1.8.2  Modified and Recommissioned Separations Facility	26
1.9  Project Infrastructure	27
1.10 Market Studies and Contracts	28
1.11 Environmental, Closure and Permitting	29
1.12 Capital and Operating Costs	29
1.13 Economic Analysis	30
1.14 Conclusions and Recommendations	31
2   Introduction	33
2.1  Registrant for Whom the Technical Report Summary was Prepared	33
2.2  Terms of Reference and Purpose of the Report	33
2.3  Sources of Information	33
2.4  Details of Inspection	33
2.5  Report Version Update	34
2.6  Units of Measure	34
2.7  Mineral Resource and Mineral Reserve Definitions	34
2.8  Qualified Person	35
3   Property Description and Location	37
3.1  Property Location	39
3.2  Mineral Title	39
3.2.1  Nature and Extent of Registrant’s Interest	42
3.3  Royalties, Agreements, and Encumbrances	42
3.4  Environmental Liabilities and Permitting	42
3.4.1  Remediation Liabilities	43

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3.4.2  Required Permits and Status	43
3.5  Other Significant Factors and Risks	44
4   Accessibility, Climate, Local Resources, Infrastructure, and Physiography	45
4.1  Topography, Elevation, and Vegetation	45
4.2  Accessibility and Transportation to the Property	45
4.3  Climate and Length of Operating Season	45
4.4  Infrastructure Availability and Sources	46
5   History	47
5.1  Prior Ownership and Ownership Changes	47
5.2  Exploration and Development Results of Previous Owners	47
5.3  Historic Production	49
6   Geological Setting, Mineralization and Deposit	53
6.1  Regional Geology	53
6.2  Local and Property Geology	55
6.2.1  Local Lithology	57
6.2.2  Alteration	58
6.2.3  Structure	58
6.3  Significant Mineralized Zones	59
6.4  Surrounding Rock Types	63
6.5  Relevant Geological Controls	63
6.6  Deposit Type, Character, and Distribution of Mineralization	63
7   Exploration and Drilling	64
7.1  Exploration	64
7.2  Drilling	64
8   Sample Preparation, Analysis and Security	66
8.1  Historical Sampling	66
8.2  Sampling 2009-2011	67
8.3  Sampling 2021	67
8.4  Laboratory Analysis	67
8.4.1  Note on Assay Terminology	68
8.4.2  Historical	69
8.4.3  Current	69
8.4.4  2009 and 2010 Samples	69
8.4.5  2011 Samples	70
8.4.6  2021 Samples	70
9   Data Verification	71

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9.1  Quality Assurance/Quality Control Procedures	71
9.1.1  Historical	71
9.1.2  2009-2010 Program	71
9.1.3  2011 Program	73
9.1.4  2021 Program	73
9.2  2009 Re-Assaying Program	75
9.2.1  Procedures	75
9.2.2  SGS Check Assay Sample Preparation	76
9.2.3  SGS Check Assay XRF Procedures	76
9.2.4  Mountain Pass Laboratory Check Assay XRF Procedures	77
9.2.5  Analysis of Light Rare Earth Oxide Distribution	77
9.2.6  Analysis of Heavy Rare Earth Oxide Assays	79
9.2.7  Results	79
9.3  Data Adequacy	83
10  Mineral Processing and Metallurgical Testing	85
10.1 Background	85
10.2 Flotation Studies Versus Ore Grade	85
10.3 Concentrator Recovery Estimate	87
10.4 Separation of Individual Rare Earths	88
10.4.1  Metallurgical Testwork	89
10.4.2  Representativeness of Test Samples	91
10.4.3  Analytical Laboratories	92
10.4.4  Separations Facility Recovery Estimates	92
10.4.5  Expected Product Specifications	102
11  Mineral Resource Estimate	104
11.1 Topography and Coordinate System	104
11.2 Drillhole Database	104
11.3 Geology	107
11.3.1  Structural Model	107
11.3.2  Lithology Model	108
11.3.3  Mineralogical/Alteration Model	109
11.4 Exploratory Data Analysis	110
11.4.1  Resource Domains	110
11.4.2  Outliers	112
11.4.3  Compositing	116
11.5 Specific Gravity	116
11.6 Variogram Analysis and Modeling	117

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SEC Technical Report Summary – Mountain Pass Mine	Page 5

11.7 Block Model Limits	119
11.8 Grade Estimation	120
11.8.1  Blasthole Estimate Specifics	121
11.8.2  Exploration Estimate Specifics	122
11.9 Model Validation	122
11.10 Production Reconciliation	124
11.10.1   Blasthole “Bias”	127
11.11 Uncertainty and Resource Classification	130
11.12 Cut-Off Grade and Pit Optimization	131
11.13 Mineral Resource Statement	133
11.14 Mineral Resource Sensitivity	135
11.15 Assumptions, Parameters, and Methods	137
12  Mineral Reserve Estimate	139
12.1 Conversion Assumptions, Parameters, and Methods	139
12.1.1  Model Grade Dilution and Mining Recovery	140
12.1.2  Cut-off Grade Calculation	140
12.2 Reserve Estimate	141
12.3 Relevant Factors	142
13  Mining Methods	144
13.1 Parameters Relevant to Mine or Pit Designs and Plans	145
13.1.1  Geotechnical	145
13.1.2  Hydrogeological	149
13.2 Pit Optimization	154
13.2.1  Mineral Resource Models	154
13.2.2  Topographic Data	155
13.2.3  Pit Optimization Constraints	155
13.2.4  Pit Optimization Parameters	155
13.2.5  Optimization Process	156
13.2.6  Optimization Results	157
13.3 Design Criteria	160
13.3.1  Pit and Phase Designs	160
13.4 Mine Production Schedule	163
13.4.1  Mine Production	163
13.5 Waste and Stockpile Design	169
13.5.1  Waste Rock Storage Facility	169
13.5.2  Stockpiles	171
13.6 Mining Fleet and Requirements	172

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SEC Technical Report Summary – Mountain Pass Mine	Page 6

13.6.1  General Requirements and Fleet Selection	172
13.6.2  Drilling and Blasting	175
13.6.3  Loading	175
13.6.4  Hauling	176
13.6.5  Auxiliary Equipment	178
13.6.6  Mining Operations and Maintenance Labor	178
14  Processing and Recovery Methods	181
14.1 Historic Production	181
14.2 Current Operations	181
14.2.1  Metallurgical Control and Accounting	183
14.2.2  Plant Performance	183
14.2.3  Significant Factors	186
14.3 Individual Rare Earth Separations	186
15  Infrastructure	190
15.1 Access and Local Communities	191
15.2 Site Facilities and Infrastructure	191
15.2.1  On-Site Facilities	191
15.2.2  Explosives Storage and Handling Facilities	193
15.2.3  Service Roads	193
15.2.4  Mine Operations and Support Facilities	193
15.2.5  Waste and Waste Handling (Non-Tailings/Waste Rock)	193
15.2.6  Waste Rock Handling	194
15.2.7  Power Supply and Distribution	194
15.2.8  Natural Gas	194
15.2.9  Vehicle and Heavy Equipment Fuel	194
15.2.10   Other Energy	194
15.2.11   Water Supply	194
15.3 Tailings Management Area	196
15.4 Security	197
15.5 Communications	197
15.6 Logistics Requirements and Off-Site Infrastructure	197
15.6.1  Rail	197
15.6.2  Port and Logistics	197
16  Market Studies and Contracts	198
16.1 Abbreviations	198
16.2 Introduction	198
16.3 General Market Outlook	199

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SEC Technical Report Summary – Mountain Pass Mine	Page 7

16.3.1  Historical Pricing	199
16.3.2  Market Balance	203
16.3.3  Costs	206
16.4 Products and Markets	208
16.4.1  Mixed Rare Earth Concentrate	208
16.4.2  PrNd Oxide	210
16.4.3  SEG+ Oxalate	213
16.4.4  La Carbonate	216
16.4.5  Cerium Chloride	218
16.5 Specific Products	222
16.5.1  Concentrate	222
16.5.2  PrNd Oxide	223
16.5.3  SEG+ Oxalate	224
16.5.4  La Carbonate	225
16.5.5  Cerium Chloride	225
16.6 Conclusions	226
16.7 Contracts	227
17  Environmental Studies, Permitting, and Closure	229
17.1 Environmental Study Results	229
17.2 Required Permits and Status	229
17.3 Mine Closure	230
18  Capital and Operating Costs	231
18.1 Capital Cost Estimates	231
18.1.1  Mining Capital Cost	231
18.1.2  Separations Facility Capital Cost	233
18.1.3  Other Sustaining Capital	233
18.1.4  Closure Costs	234
18.1.5  Basis for Capital Cost Estimates	234
18.2 Operating Cost Estimates	235
18.2.1  Mining Operating Cost	235
18.2.2  Processing Operating Cost	237
18.2.3  Selling, General, and Administrative Operating Costs	239
19  Economic Analysis	240
19.1 General Description	240
19.2 Basic Model Parameters	240
19.3 External Factors	240
19.3.1  Pricing	240

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19.3.2  Taxes and Royalties	241
19.3.3  Working Capital	241
19.4 Technical Factors	241
19.4.1  Mining Profile	241
19.4.2  Processing Profile	242
19.4.3  Operating Costs	243
19.4.4  Mining	245
19.4.5  Processing	245
19.4.6  G&A Costs	245
19.4.7  Capital Costs	245
19.4.8  Results	246
19.4.9  Sensitivity Analysis	247
19.4.10 Cash Flow Snapshot	247
20  Adjacent Properties	249
21  Other Relevant Data and Information	250
22  Interpretation and Conclusions	251
22.1 Mineral Resource Estimate	251
22.2 Mineral Reserve Estimate	251
22.3 Metallurgy and Processing	253
22.3.1  Existing Crushing and Concentration Operations	253
22.3.2  Modified and Recommissioned Separations Facility	253
22.4 Project Infrastructure	253
22.5 Products and Markets	254
22.6 Environmental, Closure, and Permitting	254
22.7 Projected Economic Outcomes	255
23  Recommendations	256
24  References	258
25  Reliance on Information Provided by the Registrant	259
Signature Page	260

List of Tables

Table 1-1: Product Specifications	20
Table 1-2: Mineral Resource Statement for the Mountain Pass Rare Earth Project, September 30, 2021	22
Table 1-3: Mineral Reserves at Mountain Pass as of September 30, 2021 - SRK Consulting (U.S.), Inc.	24
Table 1-4: Cash Flow Summary	31
Table 2-1: Site Visits	34

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SEC Technical Report Summary – Mountain Pass Mine	Page 9

Table 3-1: Current Financial Assurance Obligations	43
Table 5-1: Production History, 1952 to 1970	50
Table 5-2: Mine Production History, 1971 to 2002	51
Table 5-3: Mountain Pass Production History, 2009 to 2015, as Separated RE Products	51
Table 5-4: Mountain Pass Production History, 2018 to 2021, as Bastnaesite Concentrate	52
Table 8-1: Oxides and TREO Detection Limits, Mountain Pass Laboratory	69
Table 8-2: Oxides and Element Detection Limits, Actlabs Laboratory	70
Table 9-1: Oxides Analyzed with Detection Limits	77
Table 9-2: Light Rare Earth Oxide Distribution Statistics: 2009 and 2010 Analyses	77
Table 9-3: Light Rare Earth Oxide Distribution Statistics: 2011 Analyses	78
Table 9-4: Light Rare Earth Oxide Distribution Statistics: 2009, 2010 and 2011 Analyses	78
Table 9-5: Light Rare Earth Oxide Assay Statistics: 2009 and 2010 Analyses	78
Table 9-6: Heavy Rare Earth Summary	79
Table 9-7: Standards with Expected Analytical Performance	80
Table 10-1: Head Analyses for Grade Range Test Composites	86
Table 10-2: Cumulative Rougher Flotation Concentrate Grade and Recovery Versus Ore Grade	86
Table 10-3: Estimated Rougher and Cleaner Flotation REO Recovery (1)	87
Table 10-4: Analytical Laboratories	92
Table 10-5: Feed Conditions That Resulted in Optimal Extractions at 109 g/L	94
Table 10-6: Test Material Feed Composition by % Solid REO	95
Table 10-7: Outlet Stream Composition by g/L REO at 109 g/L	95
Table 10-8: Settling Test Results Including Overflow Clarity with Various Flocculants and Dosages	95
Table 10-9: Assays of Feed, Cell of Complete Rare Earth Breakthrough, and Cell of Fe/U Bleed	98
Table 10-10: Mass Balance Calculations for Outlet Streams at Various Fractions	98
Table 10-11: Volumetric Flowrates of Different Streams along with Mass Flowrates of Different Components	99
Table 10-12: Impurities in Brine Before and After Treatment	102
Table 11-1: TREO Influence Limitations	113
Table 11-2: 2009 Specific Gravity Results - Carbonatite	117
Table 11-3: Block Model Specifications	120
Table 11-4: Blasthole vs. Exploration Comparison	128
Table 11-5: Cut-Off Grade Input Parameters	131
Table 11-6: Mineral Resource Statement Exclusive of Mineral Reserves for the Mountain Pass Rare Earth Project, September 30, 2021	134
Table 11-7: Mineral Resources Inclusive of Mineral Reserves for the Mountain Pass Rare Earth Project, September 30, 2021	135
Table 11-8: TREO Cut-off Sensitivity Analysis Within Resource Pit – Measured and Indicated Category	136
Table 11-9: TREO COG Sensitivity Analysis Within Resource Pit – Inferred Category	136

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SEC Technical Report Summary – Mountain Pass Mine	Page 10

Table 11-10: Mineralized Material Internal and External to Resource Pit	137
Table 12-1: Pit Optimization Inputs	141
Table 12-2: Mineral Reserves at Mountain Pass as of September 30, 2021, SRK Consulting	142
Table 13-1: Recommended Slope Design Parameters	148
Table 13-2: CNI Preliminary Recommended Slope Design Parameters by Design Sector	149
Table 13-3: CNI Final Recommended Slope Design Parameters by Design Sector	149
Table 13-4: Summary of Pit Water Production in First Half of 2021	152
Table 13-5: Block Model Block Sizes	154
Table 13-6: Pit Optimization Parameters	156
Table 13-7: Mountain Pass Pit Optimization Result Using Indicated Classification Only	158
Table 13-8: Estimated Storage Capacity for Overburden and Stockpile Grade Material	170
Table 13-9: North, East and West Waste Dump Schedule	172
Table 13-10: Mining Equipment Requirements	174
Table 13-11: Loading Statistics by Unit Type in Waste	175
Table 13-12: Loading Productivities by Unit Type in Waste	176
Table 13-13: Hauling Statistics by Unit Type in Waste	176
Table 13-14: Pit Haulage Cycle Times (minutes)	177
Table 13-15: Hauling Productivities	177
Table 13-16: Mining Operations and Maintenance Labor Requirements	180
Table 14-1: Historic Mill Production, 1980 to 2002	181
Table 14-2: Concentrator Production Summary - 2020	185
Table 14-3: Concentrator Production Summary - 2021 (Jan -Sept)	185
Table 16-1: Abbreviations for Market Studies and Contracts	198
Table 16-2: Summary of U.S. Facilities Monitoring and Limiting P-levels	219
Table 16-3: Summary of Long Term Price Forecasts	222
Table 17-1: Current Environmental Permits and Status	230
Table 18-1: Mining Equipment Capital Cost Estimate (US$000’s)	232
Table 18-2: Estimated Remaining Separations Facility Capital Costs	233
Table 18-3: Closure Cost Estimates	234
Table 18-4: Mining Operating Costs	236
Table 18-5: Separations Operating Costs	238
Table 18-6: Summary of MP Materials Site G&A Operating Costs	239
Table 19-1: Basic Model Parameters	240
Table 19-2: LoM Mining Summary	242
Table 19-3: LoM Processing Profile	242
Table 19-4: Mining Cost Summary	245
Table 19-5: Processing Cost Summary	245

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SEC Technical Report Summary – Mountain Pass Mine	Page 11

Table 19-6: G&A Cost Summary	245
Table 19-7: Economic Result	247
Table 25-1: Reliance on Information Provided by the Registrant	259

List of Figures

Figure 1-1: Final Pit Design and Site Layout	25
Figure 1-2: Project Cashflow	31
Figure 3-1: General Facility Arrangement (WGS84 Coordinate System)	38
Figure 3-2: Location Map	39
Figure 3-3: Land Tenure Map	41
Figure 6-1: Regional Geological Map	54
Figure 6-2: Generalized Geologic Map – Sulfide Queen Carbonatite	56
Figure 6-3: Schematic Cross Section (A-A’) of Sulfide Queen Carbonatite	57
Figure 7-1: Drilling in MP Materials Pit Area	65
Figure 9-1: 2009 Through 2010 Pit Standard Assays	72
Figure 9-2: 2009 Through 2010 Duplicates	73
Figure 9-3: 2021 Field Duplicate Analyses – MP Materials Lab	74
Figure 9-4: External Duplicate Analyses – MP vs. ALS	75
Figure 9-5: Results of Standard Analysis	81
Figure 9-6: Results of Pulp Duplicate Analysis	82
Figure 9-7: Results of Field Duplicate Analysis	83
Figure 10-1: TREO Rougher Flotation Recovery versus Concentrate Grade for Different Feed Grades	87
Figure 10-2: TREO Recovery to Cleaner Flotation Concentrate versus Feed Grade	88
Figure 10-3: Primary Processes for Stage 2 Operation	89
Figure 10-4: Recovery Estimates	93
Figure 10-5: Extraction of Rare Earth Oxides at 109 g/L with 93+% PrNd	94
Figure 10-6: Extraction of Rare Earth Oxides at 127 g/L	94
Figure 10-7: Volumes of Leach Liquor per Volume of Resin Required Before a Regeneration Cycle	97
Figure 10-8: Mass Balance	98
Figure 10-9: Diagram of the SXH Process	99
Figure 10-10: % REO in Feed, Raffinate, and Preg Liquor	100
Figure 10-11: TREO in Overflow Liquor Over Time vs Stoichiometric Feed Ratio and pH	101
Figure 10-12: Market Standard PrNd Oxide Specification and Mountain Pass Historical Results	103
Figure 11-1: Drilling Distribution near Mountain Pass Mine	105
Figure 11-2: Sample Length Histogram – Mineralized CBT	106
Figure 11-3: Geological Mapping and Fault Expressions – August 2021	107

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Figure 11-4: Plan View of 3D Geological Model	109
Figure 11-5: Histogram of TREO% within CBT	111
Figure 11-6: Cross Section Illustrating CBT Domains and TREO Grades	112
Figure 11-7: Log Probability Plot for TREO – HG Core	114
Figure 11-8: Log Probability Plot for TREO – Undifferentiated CBT	115
Figure 11-9: Example of Directional Variogram – Blastholes TREO	118
Figure 11-10: Example of Directional Variogram – Exploration TREO	119
Figure 11-11: Domain Boundary Analysis	120
Figure 11-12: Variable Orientation Surfaces for Estimation Orientation	121
Figure 11-13: NW-SE Cross Section Showing Block Grades, Composite Grades, Resource Pit Outline	123
Figure 11-14: Swath Plot (NS orientation) Comparison Between TREO Block Grades and Composite Grades	124
Figure 11-15: Spatial Comparison of MRE Grade Distribution with Blasthole Grade Distribution	125
Figure 11-16: Comparison of Resource and Grade Control Models	126
Figure 11-17: Previous Production Areas for Reconciliation Validation	128
Figure 11-18: Percent Difference BH/EXP Estimate	129
Figure 11-19: Extents of Optimized Pit Shape Relative to Surface Topography	133
Figure 11-20: Optimized pit shell and blocks >= 2.28% TREO	137
Figure 12-1: Side by Side Comparison Non-Diluted (Left) Block Model and Diluted (Right) Block Model	140
Figure 13-1: Final Pit Design and Site Layout	145
Figure 13-2: Recommended Double Bench IRA from CNI	146
Figure 13-3: Idealized Cross Section Through Mine Area and Adjacent Valleys	150
Figure 13-4: Location of Industrial and Domestic Water Supply Wells and Mine Facilities	151
Figure 13-5: Location of Monitoring Wells, Measured Water Table Elevation, and Direction of Groundwater Flow (as Q2 2021)	152
Figure 13-6: Location of Piezometers and Measured Water Levels in Pit Walls	153
Figure 13-7: Mountain Pass Pit by Pit Optimization Result	159
Figure 13-8: Mountain Pass Mineral Reserves Pit (red line) and Mineral Resources Shell (magenta line) Surface Intersection	160
Figure 13-9: Phase Design Locations	161
Figure 13-10: Final Pit Design	162
Figure 13-11: Reserve Starting Topography, September 30, 2021	163
Figure 13-12: Total Mined Material from the Open Pit (ore and waste)	164
Figure 13-13: Ore Mined from the Open Pit	164
Figure 13-14: Mined Ore Grade	165
Figure 13-15: Rehandled Material	165
Figure 13-16: Mill Concentrate Production	166
Figure 13-17: Mill Feed Grade	166

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SEC Technical Report Summary – Mountain Pass Mine	Page 13

Figure 13-18: Number of Benches Mined	167
Figure 13-19: Haul Truck Cycle Time	167
Figure 13-20: Long-Term Ore Stockpile End of Period Balance	168
Figure 13-21: Final Pit Design and Waste Dump Locations	171
Figure 14-1: MP Materials Concentrator Flowsheet	182
Figure 14-2: Rare Earth Distribution in Flotation Concentrate	187
Figure 15-1: Facilities General Location	192
Figure 15-2: Water Supply System	195
Figure 15-3: Northwest Tailings Disposal Facility	196
Figure 16-1: Annualized PrNd Price Volatility	200
Figure 16-2: PrNd Oxide Price History	201
Figure 16-3: SEG Oxide Price History	202
Figure 16-4: La Oxide Price History	202
Figure 16-5: Ce Oxide Price History	203
Figure 16-6: Sizeable Supply Gap Emerges in the Late-2020s without Prompt New Investment	204
Figure 16-7: CRU’s LT Base Case Envisages enough Supply to Meet 10-15 Weeks’ Worth of Global Stocks	204
Figure 16-8: Magnet Material Prices will Need to Rise to Stimulate a Supply Response	205
Figure 16-9: Rare Earth Market Balance Forecast	206
Figure 16-10: Operational Rare Earths Mining Cost Curve, 2025, US$/kg REO	207
Figure 16-11: Mixed Rare Earth Concentrate Price Forecast	209
Figure 16-12: PrNd Oxide Price Forecast	211
Figure 16-13: SEG Oxalate Price Forecast	214
Figure 16-14: La Carbonate Price Forecast	217
Figure 16-15: CeCl3 Price Forecast	220
Figure 18-1: Mining Unit Cost Profile	236
Figure 19-1: Mining Profile	242
Figure 19-2: Concentrate Production	243
Figure 19-3: Separations Production Profile	243
Figure 19-4: Annual Operating Costs	244
Figure 19-5: LoM Operating Costs	244
Figure 19-6: Capital Expenditure Profile	246
Figure 19-7: Annual Cash Flow	246
Figure 19-8: After-Tax Sensitivity Analysis	247
Figure 19-9: Mountain Pass Annual Cashflow (US$ millions)	248

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SEC Technical Report Summary – Mountain Pass Mine	Page 14

Appendices

Appendix A: Claims List

Appendix B: Grade Estimation Details

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List of Abbreviations

The US System for weights and units has been used throughout this report. Tons are reported in short tons of 2,000 lb, drilling and resource model dimensions and map scales are in ft. All currency is in U.S. dollars (US$) unless otherwise stated.

The following abbreviations may be used in this report.

Abbreviation	Unit or Term
A	ampere
AA	atomic absorption
A/m2	amperes per square meter
amsl	meters above mean sea level
ANFO	ammonium nitrate fuel oil
AP	Action Plan
°C	degrees Centigrade
CCD	counter-current decantation
CIL	carbon-in-leach
cm	centimeter
cm2	square centimeter
cm3	cubic centimeter
cfm	cubic feet per minute
CHP	combined heat and power plant
COG	cut-off grade
ConfC	confidence code
CRec	core recovery
CSS	closed-side setting
CTW	calculated true width
CUP	Conditional Use Permit
°	degree (degrees)
dia.	diameter
EIR	Environmental Impact Report
EIS	Environmental Impact Statement
EMP	Environmental Management Plan
FA	fire assay
Factor of Safety	FoS
ft	foot (feet)
ft2	square foot (feet)
ft3	cubic foot (feet)
g	gram
gal	gallon
g/L	gram per liter
g-mol	gram-mole
gpm	gallons per minute
g/t	grams per metric tonne
ha	hectares
HDPE	Height Density Polyethylene
hp	horsepower
HREE	heavy rare earth elements
HRSG	heat recovery steam generators
HTW	horizontal true width
ICP	inductively coupled plasma
ID2	inverse-distance squared
ID3	inverse-distance cubed
IFC	International Finance Corporation
ILS	Intermediate Leach Solution
kA	kiloamperes
kg	kilograms

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SEC Technical Report Summary – Mountain Pass Mine	Page 16

Abbreviation	Unit or Term
km	kilometer
km2	square kilometer
koz	thousand troy ounce
kt	thousand tonnes
kt/d	thousand tonnes per day
kt/y	thousand tonnes per year
kV	kilovolt
kW	kilowatt
kWh	kilowatt-hour
kWh/t	kilowatt-hour per metric tonne
L	liter
L/sec	liters per second
L/sec/m	liters per second per meter
lb	pound
LLDDP	Linear Low Density Polyethylene Plastic
LOI	Loss on Ignition
LoM	life-of-mine
LREE	light rare earth elements
LUS	Land Use Services
m	meter
m2	square meter
m3	cubic meter
mg/L	milligrams/liter
mL	milliliter
mm	millimeter
mm2	square millimeter
mm3	cubic millimeter
MME	Mine & Mill Engineering
Moz	million troy ounces
Million short tons	million short tons
mtw	measured true width
MW	million watts
m.y.	million years
NGO	non-governmental organization
NTU	nephelometric turbidity unit
oz	troy ounce
%	percent
PLC	Programmable Logic Controller
PLS	Pregnant Leach Solution
PMF	probable maximum flood
ppb	parts per billion
ppm	parts per million
QA/QC	Quality Assurance/Quality Control
RC	rotary circulation drilling
RCRA	Resource Conservation and Recovery Act
REE	rare earth elements
REO	rare earth oxide
RF	Revenue Factor
RO	reverse osmosis
RoM	Run-of-Mine
RQD	Rock Quality Description
SEC	U.S. Securities & Exchange Commission
sec	second
SG	specific gravity
SLS	spent leach solution
SPT	standard penetration testing
st	short ton (2,000 pounds)
SX	solvent extraction
SXD	solvent extraction didymium

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 17

Abbreviation	Unit or Term
SXH	solvent extraction heavies
SXI	solvent extraction impurities
t	tonne (metric tonne) (2,204.6 pounds)
t/h	tonnes per hour
t/d	tonnes per day
t/y	tonnes per year
TEM	technical economic model
TREO	total rare earth oxide
TSF	tailings storage facility
TSP	total suspended particulates
TVR	thermal vapor recompression
µm	micron or microns
V	volts
VFD	variable frequency drive
W	watt
XRD	x-ray diffraction
y	year
yd3	cubic yard

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 18

1 Executive Summary

This report was prepared as a pre-feasibility level Technical Report Summary in accordance with the Securities and Exchange Commission (“SEC”) S-K regulations (Title 17, Part 229, Items 601 and 1300 until 1305) for MP Materials Corp. (“MP Materials”) by SRK Consulting (U.S.), Inc. (“SRK”) on the Mountain Pass Mine (“Mountain Pass”).

Sections of this report pertaining to the modification and recommissioning of the rare earth element (REE) separations facility at Mountain Pass were authored by SGS North America Inc. (“SGS”). Portions of this report pertaining to products and markets, including long term price forecast for REE products, were authored by CRU International Limited (“CRU”).

1.1 Property Description and Ownership

Mountain Pass is located in San Bernardino County, California, north of and adjacent to Interstate-15 (I-15), approximately 15 miles (mi) southwest of the California-Nevada state line and 30 mi northeast of Baker, California, at geographic coordinates 35°28’56”N latitude and 115°31’54”W longitude. This area is part of the historic Clark Mining District established in 1865. Mountain Pass is the only rare earth deposit identified within this district. The Project lies within portions of Sections 11, 12, 13, and 14 of Township 16 North, Range 14 East, San Bernardino Base and Meridian.

On November 17, 2020, pursuant to a merger agreement dated July 15, 2020, MP Mine Operations LLC (“MPMO”) and Secure Natural Resources LLC (“SNR”), the company that holds the mineral rights to the mine, were combined with Fortress Value Acquisition Corp., a special purpose acquisition company (“FVAC”) (the “Business Combination”). In connection with the Business Combination, MPMO and SNR became subsidiaries of FVAC, which was in turn renamed MP Materials Corp.

Mining claims and surface rights associated with the Project include:

• Patented claims with surface rights owned by MPMO and mineral rights held by SNR

• Unpatented lode and mineral claims held by SNR

• Surface ownership by MPMO and mineral rights controlled by the State of California

• Surface ownership by MPMO and mineral rights controlled by the U.S.

• Surface ownership by School District and mineral rights controlled by the U.S.

The rare earth mineralization at the Project is located within land either owned or leased by MP Materials.

1.2 Geology and Mineralization

The Mountain Pass deposit is a rare-earth-element-enriched carbonatite historically referred to as the Sulfide Queen orebody. The carbonatite and numerous other alkaline intrusives in the vicinity are hosted in gneissic rocks which have been altered (fenitized) by the intrusive bodies. Multiple carbonatite dikes are present throughout the area. Small dikes and breccia bodies surround the Sulfide Queen orebody which comprises several different types of carbonatite (sovite, beforsite, dolosolvite, and white sovite) which are interlayered within a relatively large carbonatite package, this is unique in terms of size of the concession, and globally significant in terms of its enrichment in rare-earth minerals.

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 19

The southern part of the Sulfide Queen orebody strikes to the south southeast and dips at 40° to the west southwest; the northern part of the orebody strikes to the north northeast and dips at some 40° to the west north-west. A number of post-mineralization faults result in slight offsets to the otherwise simple tabular/lensoid geometry. The total orebody strike length is approximately 2,750 feet (ft) and dip extent is 3,000 ft; true thickness of the more than 2% total rare earth oxide (TREO) grade zone ranges between 15 ft and 250 ft.

The main rare-earth-bearing mineral, bastnaesite, is present in all carbonatite subtypes, but in relatively lower proportions in the breccias and the monazitic carbonatites which typically occur mainly outside of and close to the main orebody. Monazite and crocidolite (“blue ore” found on the hangingwall contact in the northern part of the orebody) are both undesirable in the processing plant. In some areas, post mineral fault zones provide a conduit for water which results in localized alteration of the fresh carbonatite. Alteration dissolves the calcite and dolomite gangue minerals, leaving behind elevated concentrations of bastnaesite with limonite resulting in what is referred to as brown and black ore types, the most altered of which become a loosely consolidated very high grade bastnaesite sand. The altered ore types are mined, stockpiled separately and blended at a minor proportion to maintain target ore grades in the mill feed blend.

1.3 Status of Exploration, Development and Operations

The Mountain Pass mine is an active operating mine. The primary mineral of economic interest is bastnaesite. MP Materials mines ore from the open pit, transports the ore to a primary crushing/stockpile facility and transports the ore to the mill. At the mill, the crushed material is ground further with a ball mill and conveyed via a slurry pipeline to the flotation plant to separate the bastnaesite from the gangue minerals. The primary product of the flotation process is a bastnaesite concentrate, which is filter dried and then transported to customers for sale. MP Materials is in the process of recommissioning a rare earths separations facility that is scheduled to be operational by year-end 2022. The separations facility, once operational, will allow the Company to separate the bastnaesite concentrate into four saleable products: praseodymium and neodymium (PrNd) oxide, samarium, europium, and gadolinium (SEG+) oxalate, lanthanum (La) carbonate, and cerium (Ce) chloride.

MP Materials relies on predecessor companies, the United States Geological Survey (USGS) (Olson and others, 1954), and various consulting companies for interpretations related to the regional and mine area geology and hydrogeology, regional and local structure, and deposit geology. Mineral Processing and Metallurgical Testing.

1.4 Mineral Processing and Metallurgical Testing

1.4.1 Existing Crushing and Concentrating Operations

During the later years of mining operations at Mountain Pass, the ore grade is expected to decline. To assess TREO (total rare earth oxide) recovery from lower grade ore, MP Materials conducted rougher flotation tests on ore samples over a grade range from 1.86 - 8.10% TREO using standard concentrator test conditions. Based on the results of this testwork, MP Materials has developed a mathematical relationship to estimate overall TREO recovery versus ore grade. This relationship has been used to estimate TREO recovery from lower grade ores later in the mine life.

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 20

1.4.2 Rare Earths Separations

It is the intention of MP Materials to modify the current operations to produce four marketable rare earth products in the future (PrNd oxide, SEG+ oxalate, La carbonate/La oxide, and Ce chloride). The specifications for the four products are shown in Table 1-1, with further discussion on the product specification provided in Section 14.6

Table 1-1: Product Specifications

Product	Compound	w/w % TREO	Purity
PrNd Oxide	75% Nd2O3 + 25% Pr6O11 (+/-2%)	99%	99.5%+ PrNd/TREO
SEG+ Oxalate/Concentrate	-	25% to 45%	99% SEG+/TREO
Lanthanum Carbonate	La2(CO3)3 + La2O3	99%	99% La/TREO
Cerium Chloride	LaCeCl3	45%	85% Ce/TREO

Note: w/w % is the weight concentration of the solution.

Source: MP Materials, 2021

The work effort to develop the design criteria for processing facility modifications are briefly described below and are detailed in Section 10.4. Unit operations for the modified facilities are described below.

Concentrate Drying and Roasting

Concentrate drying and roasting was practiced at Mountain Pass commencing in the mid 1960’s. Tonnage quantity roasting test work to confirm optimum operating parameters was conducted at Hazen Research. Studies involving the definition of specific leaching conditions were conducted at SGS Lakefield and at Mountain Pass facilities. These studies served to elucidate optimum operational conditions. Of major importance was the adjustment of roasting parameters such that leaching dissolved trivalent rare earths and left the majority of the cerium undissolved.

Leaching

Optimization studies to specify the most appropriate leaching parameters were conducted at several external laboratories and at MP Materials Cerium 96 leaching facility. MP Materials upgraded a small-scale onsite leaching pilot facility which provided superior temperature control so as to define the optimum leach facility operating conditions. The leaching operations produced an undissolved cerium concentrate and solubilized trivalent rare earths plus dissolved impurities.

Impurity Removal

Soluble impurities in the leach solution include iron, aluminum, uranium, calcium, magnesium, and other minor quantities of dissolved elements. The MP Materials solvent extraction system used for this duty has been successfully used for a number of years.

SXH and SXD

The solvent extraction heavies (SXH) circuit makes a bulk separation of heavy rare earths and the solvent extraction didymium (SXD) circuit separates a PrNd stream. These circuits have been piloted and have been demonstrated to function as designed.

Brine Recovery, Treatment, Crystallizing: MP Materials has conducted several rounds of pilot studies taking appropriate mixtures of brine from previously operated facilities and solvent extraction (SX) pilot plant investigations to produce a representative brine. Past experience coupled with recent modeling work indicate that the system has sufficient capacity to handle anticipated feed volumetric changes.

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 21

Conclusions

As with any extensive process modification effort, all possible contingencies may not be anticipated. However, based upon the project documentation provided, a site visit to the MP Materials installations at Mountain Pass, an interview with the manager of ongoing construction and conversations with MP Materials engineers who will be directly involved with the commissioning efforts, it is the opinion of SGS North America Inc. (SGS) that the Mountain Pass modification and modernization project has been performed in a professional manner. It is also SGS’s opinion that it is likely that the project schedule and commissioning efforts will be accomplished in the stipulated time frame, which is currently assumed to be year-end 2022.

1.5 Mineral Resource Estimate

The Mineral Resources are reported in accordance with the S-K regulations (Title 17, Part 229, Items 601 and 1300 until 1305). 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. The Mineral Resource modelling and reporting was completed by SRK Consulting (U.S.) Inc.

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.

SRK has dealt with uncertainty and risk at Mountain Pass by classifying the contained resource by varying degrees of confidence in the estimate. The mineral resources at the Mountain Pass deposit have been classified in accordance with the S-K 1300 regulations. The classification parameters are defined by both the distance to composite data, the number of drillholes used to inform block grades and a geostatistical indicator of relative estimation quality (kriging efficiency). 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.

A cut-off grade (COG) of 2.28% TREO has been developed to ensure that material reported as a mineral resource can satisfy the definition of reasonable potential for eventual economic extraction (RPEEE). Mineral resources have been constrained within an economic pit shell based on reserve input parameters. For mineral resources, a revenue factor of 1.0 is selected which corresponds to a break-even pit shell. 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 rare earth oxide (REO) concentrator.

The September 30, 2021, mineral resource statement is shown in Table 1-2. The reference point for the mineral resources is in situ material.

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 22

Table 1-2: Mineral Resource Statement for the Mountain Pass Rare Earth Project, September 30, 2021

Category	Resource Type	Cut-Off TREO%	Mass (million sh. ton)	Average Value
				TREO(1) (%)	La2O3(2) (%)	CeO2 (%)	Pr6O11 (%)	Nd2O3 (%)	Sm2O3 (%)
Indicated	Within the Reserve Pit	2.28-2.49	0.9	2.38	0.78	1.19	0.10	0.29	0.02
	Within the Resource Pit	2.28	0.5	3.61	1.18	1.80	0.16	0.44	0.03
Total Indicated			1.4	2.82	0.92	1.41	0.12	0.34	0.03
Inferred	Within the Reserve Pit	2.28-2.49	7.1	5.48	1.78	2.73	0.24	0.66	0.05
	Withing the Resource Pit	2.28	2.1	3.81	1.24	1.90	0.16	0.46	0.03
Total Inferred			9.1	5.10	1.66	2.54	0.22	0.62	0.05

Source: SRK 2021

⁽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 0.90% 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 Mineral Reserves estimate.

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

• Mineral Resource tonnage and grade are reported as diluted.

• The Mineral Resource model has been depleted for historical and forecast mining based on the September 30, 2021, pit topography.

• Pit optimization cut-off grade is based on an average TREO% equivalent concentrate price of US$7,059/st of dry concentrate (60% TREO, net of the incremental benefits and costs related to REE separations), average mining cost at the pit exit of US$1.825/st mined plus US$0.018/st mined for each 15 ft bench above or below the pit exit, combined milling and G&A costs of US$69.90/st milled, concentrate freight of US$177/st of dry concentrate, and an average overall pit slope angle of 42° including ramps.

• The mineral resource statement reported herein only includes the rare earth elements cerium, lanthanum, neodymium, praseodymium, and samarium (often referred to as light rare earths). While other rare earth elements, often referred to as heavy rare earths, are present in the deposit, they are not accounted for in this estimate due to historic data limitations (see Section 9.2.6).

1.6 Mineral Reserve Estimate

SRK developed a life-of-mine (LoM) plan for the Mountain Pass operation in support of mineral reserves. For economic modeling, 2022 production was assumed to be bastnaesite concentrate. From 2023 onward, it was assumed that MP Materials will operate a separations facility at the Mountain Pass site that will allow the Company to separate bastnaesite concentrate into four individual REO products for sale (PrNd oxide, SEG+ oxalate, La carbonate/La oxide, and Ce chloride). Forecast economic parameters are based on current 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 MP Materials, as discussed in Section 16 of this report.

From this evaluation, pit optimization was performed based on an equivalent concentrate price of US$6,139 per dry st of 60% TREO concentrate (net of the incremental benefits and costs related to REE separations). The results of pit optimization guided the design and scheduling of the ultimate pit.

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 23

SRK generated a cash flow model which indicated positive economics for the LoM plan, which provides the basis for the reserves. Reserves within the new ultimate pit are sequenced for the full 35-year LoM. There is a partial year of stockpile processing after mining of in situ reserves is completed.

The costs used for pit optimization include estimated mining, processing, sustaining capital, transportation, and administrative costs, including an allocation of corporate costs. Processing and G&A costs used for pit optimization were based on 12-month rolling average actual costs from August 2020 – July 2021. Processing and G&A costs used for economic modeling were updated subsequent to pit optimization and are based on January 2021 – September 2021 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 2.49% 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 design are based on geotechnical studies and range from 42° 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, as described herein, to potential mining pit shapes created during the mine design process. Inferred resources present within the LoM pit are treated as waste.

The mine design process results in in situ open pit mining reserves of 30.45 million st with an average grade of 6.35% TREO. Table 1-3 presents the mineral reserve statement, as of September 30, 2021, for the Mountain Pass mine (MP Materials’ mining engineers provided a month-end September 2021 topography as a reserve starting point). The reference point for the mineral reserves is ore delivered to the Mountain Pass concentrator.

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 24

Table 1-3: Mineral Reserves at Mountain Pass as of September 30, 2021 - SRK Consulting (U.S.), Inc.

Category	Description	Run-of-Mine  (RoM)		TREO%		MY%		Concentrate
		Million Short Tons (dry)						Million Short Tons (dry)
Proven	Current Stockpiles		0.05		9.45		10.88		0.01
	In situ		-		-		-		-
	Proven Totals		0.05		9.45		10.88		0.01
Probable	Current Stockpiles		-		-		-		-
	In situ		30.4		6.35		6.74		2.05
	Probable Totals		30.4		6.35		6.74		2.05
Proven + Probable	Current Stockpiles		0.05		9.45		10.88		0.01
	In situ		30.4		6.35		6.74		2.05
	Proven + Probable Totals		30.45		6.36		6.75		2.05

Source: SRK, 2021

General Notes:

• Reserves stated as contained within an economically minable open pit design stated above a 2.49% 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. A small difference of approximately 0.3% between the reserve tonnage and the ore tonnage used in the cashflow model is not considered to be material.

• MY% 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 ft x 15 ft x30 ft).

• Mineral reserves tonnage and grade are reported as diluted.

• Pit optimization COG is based on an average TREO% equivalent concentration price of US$6,139/st of dry concentrate (60% TREO, net of the incremental benefits and costs related to REE separations), average mining cost at the pit exit of US$1.825/st mined plus US$0.018/st mined for each 15 ft bench above or below the pit exit, combined milling and G&A costs of US$69.90/st milled, concentrate freight of US$177/st of dry concentrate, and an average overall pit slope angle of 42° including ramps.

• The topography used was from September 30, 2021.

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

• Reserves assume 100% mining recovery.

• The strip ratio was 6.1 to 1 (waste to ore ratio).

• The mineral reserves were estimated by SRK Consulting (U.S.) Inc.

The reserve estimate herein is subject to potential change based on changes to the forward-looking cost and revenue assumptions utilized in this study. It is assumed that MP Materials will produce and sell bastnaesite concentrate to customers in 2022. It is further assumed that MP Materials will ramp its on-site separations facilities (currently undergoing modification and recommissioning) as discussed in Section 10.4 and will transition to selling separated rare earth products starting in 2023.

Full extraction of this reserve is dependent upon modification of current permitted boundaries. Failure to achieve modification of these boundaries would result in MP Materials not being able to extract the full reserve estimated in this study. It is MP Materials’ expectation that it will be successful in modifying this permit condition. In SRK’s opinion, MP Materials’ expectation in this regard is reasonable.

A portion of the pit encroaches on an adjoining mineral right holder’s concession. This portion of the pit only includes waste stripping (i.e., no rare earth mineralization is assumed to be extracted from this concession). The prior owner of Mountain Pass had an agreement with this concession holder to allow this waste stripping (with the requirement that aggregate mined be stockpiled for the owner’s use). MP Materials does not currently have this agreement in place, but SRK believes it is reasonable to assume that MP Materials will be able to negotiate a similar agreement.

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 25

1.7 Mining Methods

Mountain Pass is currently being mined using conventional open-pit methods. The open pit is in gently undulating topography intersecting natural drainages that require diversion to withstand some rainfall events during the summer and winter months. Waste dumps are managed according to the Action Plan (AP), are located on high ground, and are designed for control of drainage (contact water) if required.

The open pit that forms the basis of the mineral reserves and the LoM production schedule is approximately 3,100 ft from east to west and 3,800 ft from north to south with a maximum depth of 1,400 ft. Total mining is estimated at 216 million st comprised of 30.4 million st of ore and 186 million st of waste, resulting in a strip ratio of 6.1 (waste to ore). Mined ore grade averages 6.35% TREO yielding over 2.05 million dry st of recoverable 60% TREO concentrate. SRK designed four pit pushbacks that adhere to proper minimum mining widths. Bench sinking rates are approximated to no more than six benches per year per pushback.

Figure 1-1 illustrates the site layout and final pit design (the tailings area is not highlighted in this image).

16000 N 15000 N 14000 N 13000 N 12000 N 11000 N 10000 N 9000 N 8000 N 7000 N 1000 E 2000 E 3000N 4000 E 5000 E 6000 E 7000 E 8000 E 9000 N 10000 E 11000 E 12000 E 13000 E 14000 E

Source SRK, 2021

Figure 1-1: Final Pit Design and Site Layout

Mine activities include drilling, blasting, loading, hauling, and mining support activities. Drill and blast operations are performed by a contractor, and this will continue for the foreseeable future. All other mine operations are performed by MP Materials. The primary loading equipment is front-end loaders

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 26

(15 cubic yards (yd³)), which were selected for operational flexibility. Rigid frame haul trucks with 102 wet short tons (wst) capacity were selected to match with the loading units.

Material within the pit will be blasted on 30 ft high benches. Material classified as reserves (>2.49% TREO) will be sent to the RoM stockpiles for near-term blending to the primary crusher or, alternatively, to long-term stockpiles for processing later in the mine life. Waste dumps will be used for material below 2.49% TREO.

The mine operations schedule includes one 12-hour day shift, seven days per week for 365 days per year.

1.8 Recovery Methods

1.8.1 Existing Crushing and Concentrating Operations

MP Materials operates a 2,000 t/d flotation concentrator that produces concentrates that are currently sold to customers who further process the concentrates to produce separated rare earth oxides. The concentrator flowsheet includes crushing, grinding, rougher/scavenger flotation, cleaner flotation, concentrate thickening and filtration and tailings thickening and filtration followed by dry stack tailings disposal. Significant improvements in concentrator performance have occurred since inception of operations, which are attributed primarily to new reagent and ore blending schemes as well as the introduction of steam boiler to support process kinetics. During 2020 TREO recovery averaged 66.8% into concentrates containing an average of 60.6% TREO. During 2021 (January – September) TREO recovery has averaged 69.8% into concentrates averaging 61.2% TREO, reflecting ongoing operational improvements in the concentrator.

1.8.2 Modified and Recommissioned Separations Facility

MP Materials is in the process of modifying and recommission its on-site separations facility to produce individual rare earth products as previously summarized in Table 1-3. The incentive for this substantial process change is the enhancement of revenue that would be realized for producing individual rare earth products as compared to the current practice of producing a single rare earth containing flotation concentrate which is then sold to various entities that separate and market individual rare earth products. MP Materials has investigated the marketability of the proposed new products and has reached the conclusion that the process modifications specified herein should go forward and has made substantial technical and financial commitments to that end.

Consequently, based upon the value of the rare earth products defined in the table above, coupled with a site visit to the MP Materials installations at Mountain Pass, an interview with the manager of ongoing construction, and conversations with MP Materials engineers that will be directly involved with the commissioning efforts, it is the opinion of SGS that the Mountain Pass modification and modernization project has been performed in an expeditious and professional manner. It is likely that the project construction completion schedule presently anticipated to complete by year-end 2022 will be realized. It is also likely that the ramp schedule assumed for economic modeling purposes, which estimated feeding 50%, 90%, and 100% of concentrate production into the facility in 2023, 2024, and 2025, respectively, is conservative and will be achieved.

February 2022

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 27

1.9 Project Infrastructure

The Project is in San Bernardino County, California, north of and adjacent to Interstate 15 (I-15), approximately 15 mi southwest of the California-Nevada state line and 30 mi northeast of Baker, California (Figure 3-2).

The nearest major city is Las Vegas, Nevada, located 50 mi to the east on I-15. The Project lies immediately north of I-15 at Mountain Pass and is accessed by the Bailey Road Exit (Exit 281 of I-15), which leads directly to the main gate. The mine is approximately 15 mi southwest of the California-Nevada state line in an otherwise undeveloped area, enclosed by surrounding natural topographic features.

Outside services include industrial maintenance contractors, equipment suppliers and general service contractors. Access to qualified contractors and suppliers is excellent due to the proximity of population centers such as Las Vegas, Nevada as well as Elko, Nevada (an established large mining district) and Phoenix, Arizona (servicing the copper mining industry).

Access to the site, as well as site haul roads and other minor roads are fully developed and controlled by MP Materials. There is no public access through the Project area. All public access roads that lead to the Project are gated at the property boundary.

MP Materials has fully developed an operating infrastructure for the Project in support of extraction and concentrating activities. A manned security gate is located on Bailey Road for providing required site-specific safety briefings and monitoring personnel entry and exit to the Project.

The site has a 12-kV electrical powerline that supplies the full power needs of the Project in its current configuration. The site also uses piped natural gas to supply a rental boiler used to provide steam for the concentrator plant. Development activities completed by the prior Project owner included the construction of a Combined Heat and Power (CHP) or co-generation (cogen) power facility to address the increased electrical demands associated with the process flow sheet utilized at that time. This CHP plant is in the final stages of being recommissioned and is expected to provide for all the electricity and steam needs for all process areas of the site in early 2022, replacing the need for grid power and the rental boiler.

Water is supplied through active water wells, legacy treatment wells, mine dewatering, and natural precipitation. The Project has a net positive water balance and excess water is evaporated in evaporation ponds. Fire systems are supplied by separate fire water tanks and pumps.

The site has all facilities required for operation, including the open pit, concentrator, access and haul roads, explosives storage, fuel tanks and fueling systems, warehouse, security guard house and perimeter fencing, tailings filter plant, tailings storage area, waste rock storage area, administrative and office buildings, surface water control systems, evaporation ponds, miscellaneous shops, truck shop, laboratory, multiple laydown areas, power supply, water supply, gas-fired boiler and support equipment, waste handling bins and temporary storage locations, and a fully developed communications system.

The LoM plan will require the relocation in 2036 of the paste tailings plant and the water tanks currently northeast of the pit highwall near the concentration plant. Additionally, the crusher will be relocated in 2027 to allow the pit to expand to the north. Capital cost provisions are included in the economic model for these relocations.

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The design capacity of the tailings storage facility is approximately 24 million st. The project has utilized approximately 3.6 million st of that space. The existing facility will have a remaining capacity of approximately 20.4 million st which will provide over 23 years of storage. MP Materials will expand the existing tailings facility to the northwest in approximately 2042 to provide an additional 13 years of storage capacity. A capital cost provision has been included in the economic model for this expansion.

Site logistics are straightforward with the current concentrate product shipped in Super Sacks within a shipping container by truck approximately 4.5 hours to the port of Los Angeles. At the port, the containers are loaded onto a container ship and shipped to the final customers.

1.10 Market Studies and Contracts

Section 16 of this report highlights key trends within the REE market, which can be categorized by a significant degree of variation in the demand profiles for various REE and their associated products.

Products outlined in this report (PrNd oxide, SEG+ oxalate, La carbonate, and Ce chloride) are considered marketable from an economic perspective, provided market standards and requirements are met. As shown in Table 1-4, and based on outlined product specifications, CRU forecasts a long-term price of US$95/kg REO for PrNd oxide, US$7.5/kg REO for SEG+ oxalate, US$1.4/kg REO for Lanthanum carbonate, and US$4.4/kg REO for Cerium chloride. The mixed rare earth concentrate price of US$10/kg of contained REO will be principally driven by trends in PrNd and dysprosium (Dy), price swings of which will be mirrored by concentrates.

Table 1-4: Summary of Long Term Price Forecasts

Product	Long term price forecast, real 2020 US$/kg
Mixed Rare Earth Concentrate	US$10 per kg of contained REO
PrNd Oxide	US$95 per kg
SEG+ Oxalate	US$7.5 per kg
La Carbonate	US$1.4 per kg
Cerium Chloride	US$4.4 per kg

Source: CRU, 2022

At a high level, when constructing an average non-China rare earths project, the long-run incentive price for PrNd is calculated at ~US$85/kg. Expectations of a potentially persistent market deficit, with PrNd prices staying well above US$100/kg out to 2028 elevate the long term price forecast to US$95/kg. The SEG+ oxalate price forecast is based on projected terms at which Chinese separation facilities with heavy rare earth capacity will aim to purchase the oxalate as feedstock. The carbonate and chloride price forecasts are based on end-use production cost analysis. These forecasts are therefore based on a variation of product-specific market trends and long-run cost methodologies specific to rare earth operations.

A strong demand profile for PrNd oxide drives a weaker profile for Ce and La products, with the basket problem driving oversupplied Ce and La markets. As a result, the long-run price for PrNd is centered on the principle that it carries the cost of production for most operations. Heavy rare earth operations also contribute to economic value beyond the cost of their extraction, but separation is generally more expensive and therefore only feasible in higher quantities than average bastnaesite or monazite orebodies. Although the Mountain Pass facility may derive value for the mixed heavy rare earth product (SEG+ oxalate), PrNd oxide contains the most economic value at the present market view. Where

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geopolitical tensions may intercede with standard market operations, Mountain Pass appears well positioned to provide market-standard products.

1.11 Environmental, Closure and Permitting

As of September 30, 2021, MP Materials holds the necessary operating permits, including conditional use and minor use permits from the County of San Bernardino (SBC), which currently allows continued operations of the Mountain Pass facility through 2042.

MP Materials maintains financial assurance cost estimates for closure, post-closure maintenance (PCM), and All Known and Reasonably Foreseeable Releases (AKRFR) for current and planned operations at the Mountain Pass property. The Lahontan Regional Water Quality Control Board (LRWQCB) administers the groundwater and surface water related financial assurance obligations. The SBC administers financial assurance requirements for surface reclamation of the property. The California Department of Resource, Recycling and Recovery administers financial assurance requirements for decontamination and decommissioning activities. MP Materials maintains miscellaneous financial assurance instruments for other closure-related obligations. As of September 2021, the total financial assurance obligation is approximately US$39 million.

1.12 Capital and Operating Costs

Capital and operating costs are incurred and reported in US dollars and are estimated at a pre-feasibility level with an accuracy of approximately +/-25%.

Capital Costs

The mine is currently operating and, as such, there is no initial capital expenditure other than for modification and recommissioning of the separations facility, which is currently underway. Recommissioning capital expenditures for the water treatment plant and the CHP plant have largely been incurred in 2021, with both units in service as of the end of 2021. All other capital expenditure as contemplated by this report is expected to be sustaining capital. Sustaining capital expenditures include the sustaining capital cost associated with the mining fleet. Also included are sustaining capital cost provisions for planned paste tailings plant, crusher and water tank relocations and the “other” category, which captures all other sustaining capital costs.

Capital costs for the separations facility modification and recommissioning have been reviewed and approved by SGS. All other capital costs have been reviewed and approved by SRK.

Table 1-4 summarizes the LoM capital costs for Mountain Pass.

Table 1-4: LoM Capital Expenditures

Category	Years Incurred		LoM Total (US$ million)
Separations Facility Modification and Recommissioning		2021-2022		210.4
Mining Equipment Replacements and Rebuilds		2021-2055		61.4
Infrastructure Relocations		2027-2036		78.0
TSF Expansion		2042		10.0
Closure		2057		39.0
Separations Facility Sustaining		2023-2055		210.5
Other Sustaining		2021-2056		537.9
Total				1,145.7

Source: SRK and SGS

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Operating Costs

For economic modeling, the operating costs are allocated among three main areas: mining, processing and site general and administrative (G&A). SRK developed a first principles operating cost forecast for mining. SGS and MP Materials developed a first principles operating cost forecast for the modified and recommissioned separations facility. Otherwise, costs are forecast based on current operating results, with appropriate adjustments for anticipated future changes in the configuration of the operation.

The estimated operating costs are presented in Table 1-5.

Table 1-5: Operating Costs

Category	LoM Total     (US$ million)		Average Unit Cost     (US$/ore ton processed)
Mining		599.1		19.6
Processing (including separations)		5,259.7		172.3
Site G&A		670.9		22.0
Total		6,529.7		213.9

Source: SRK and SGS

1.13 Economic Analysis

SRK generated an economic model for the life of the reserve stated in this report. The economic model utilized the capital and operating costs described in Section 18. Product sales price assumptions are described in Section 16 and are based on a preliminary market study. Based on this economic analysis, the reserve stated herein generates positive free cash flow and meets the economic test for the declaration of a reserve under SEC regulations.

Economic analysis, including estimation of capital and operating costs is inherently a forward-looking exercise. These estimates rely upon a range of assumptions and forecasts that are subject to change depending upon macroeconomic conditions, operating strategy and new data collected through future operations and therefore actual economic outcomes often deviate significantly from forecasts.

The Mountain Pass operation consists of an open pit mine and several processing facilities fed by the open pit mine. The operation is expected to have a 36 year life with the first modeled year of operation a partial year to align with the effective date of the reserves. The final year (also a partial year) is limited to the processing of remaining stockpiles.

The economic analysis metrics are prepared on annual after-tax basis in US$. The results of the analysis are presented in Table 1-4. The results indicate that, at prices outlined in the market study section of this report, the operation returns an after-tax net present value (NPV) at 6% of US$2.6 billion. Note, that because the mine is in operation and is valued on a total project basis with prior costs treated as sunk, internal rate of return (IRR) and payback period analysis are not relevant metrics.

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Table 1-4: Cash Flow Summary

LoM Cash Flow (unfinanced)	Units	Value
Total Revenue	US$ (million)		15,271.08
Total Opex	US$ (million)		(6,529.67	)
Operating Margin	US$ (million)		8,741.41
Operating Margin Ratio	%		57	%
Taxes Paid	US$ (million)		(2,075.10	)
Before Tax
Free Cash Flow	US$ (million)		7,595.68
NPV at 6%	US$ (million)		3,478.59
After Tax
Free Cash Flow	US$ (million)		5,520.59
NPV at 6%	US$ (million)		2,556.82

Source: SRK

A summary of the cashflow on an annual basis is presented in Figure 1-2.

Project Cashflow (unfinanced) 600 400 2000 1,000 Revenus US$ (Millions) 200 (400) (800) 2027 Operating Cost 2028 2040 Working Capital Adjustment 2037 2039 Sustaining Capital 2011 2042 2013 2048 Tax Paid - Project Net Cashflow 2051 Camulative Net Cashflow 2036

Source: SRK

Figure 1-2: Project Cashflow

1.14 Conclusions and Recommendations

Based on the data available and the analysis described in this report, in SRK’s opinion, the Mountain Pass operation has a valid mineral resource and mineral reserve, as stated herein. The mineral resource model has been updated with revised drilling information and a new geological model. The resource estimation has been validated using conventional means and reconciled against production records.

The resources and reserves are subject to potential change based on changes to the forward-looking cost and revenue assumptions utilized in this study. Rare earth concentrate sales to China are currently subject to value added tax (VAT). Sales of individual rare earth products are assumed to begin in 2023, subject to the successful modification and recommissioning of the on-site separations facility, which is currently underway.

Full extraction of this reserve is dependent upon modification of current permitted boundaries. Failure to achieve modification of these boundaries would result in MP Materials not being able to extract the full reserve estimated in this study. It is MP Materials’ expectation that it will be successful in modifying this permit condition. In SRK’s opinion, MP Materials’ expectation in this regard is reasonable.

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A portion of the pit encroaches on an adjoining mineral right holder’s concession. This portion of the pit only includes waste stripping (i.e., no rare earth mineralization is assumed to be extracted from this concession). The prior owner of Mountain Pass had an agreement with this concession holder to allow this waste stripping (with the requirement that aggregate mined be stockpiled for the owner’s use). MP Materials does not currently have this agreement in place, but SRK believes it is reasonable to assume that MP Materials will be able to negotiate a similar agreement.

Additional opportunity exists from the potential to convert current inferred resources both within the LoM pit and on the fringes of the pit. The conversion of inferred resources to either measured or indicated resources, if successful, would increase the mine life and reduce waste stripping. Therefore, SRK recommends that MP Materials target infill drilling for the purpose of this conversion and to improve definition of the higher grade and mineralogically distinct parts of the orebody. This effort should include a robust QA/QC program and an expanded assay program to better define individual rare earth components and a more comprehensive determination of density values and their relationship with grade.

Other, more minor recommendations are detailed in Section 23.

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2 Introduction

2.1 Registrant for Whom the Technical Report Summary was Prepared

This report was prepared as a pre-feasibility level Technical Report Summary in accordance with the Securities and Exchange Commission (SEC) S-K regulations (Title 17, Part 229, Items 601 and 1300 until 1305) for MP Materials Corp. (MP Materials) by SRK Consulting (U.S.), Inc. (SRK) on the Mountain Pass Mine (Mountain Pass).

2.2 Terms of Reference and Purpose of the Report

The quality of information, conclusions, and estimates contained herein are consistent with the level of effort involved in SRK’s services, based on: i) information available at the time of preparation and ii) the assumptions, conditions, and qualifications set forth in this report. This Technical Report Summary is based on pre-feasibility level engineering.

This report is intended for use by MP Materials subject to the terms and conditions of its contract with SRK and relevant securities legislation. The contract permits MP Materials to file this report as a Technical Report Summary with U.S. securities regulatory authorities pursuant to the SEC S-K regulations, more specifically Title 17, Subpart 229.600, Item 601(b)(96) - Technical Report Summary and Title 17, Subpart 229.1300 - Disclosure by Registrants Engaged in Mining Operations. Except for the purposes legislated under U.S. securities law, any other uses of this report by any third party are at that party’s sole risk. The responsibility for this disclosure remains with MP Materials.

The purpose of this Technical Report Summary is to report mineral resources and mineral reserves.

2.3 Sources of Information

This report is based in part on internal Company technical reports, previous feasibility studies, maps, published government reports, Company letters and memoranda, and public information as cited throughout this report and listed in Section 24.

Reliance upon information provided by the registrant is listed in Section 25 when applicable.

2.4 Details of Inspection

Table 2-1 summarizes the details of the personal inspections on the property by each qualified person or, if applicable, the reason why a personal inspection has not been completed.

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Table 2-1: Site Visits

Expertise	Company	Date(s) of Visit	Details of Inspection
Infrastructure	SRK Consulting (U.S.), Inc.	September 25, 2019	Infrastructure, tailings area, general site inspection
Slope Stability/ Engineering Geology	SRK Consulting (U.S.), Inc.	September 25, 2019	Open pit slopes and stockpiles
Mining/Reserves	SRK Consulting (U.S.), Inc.	September 30, 2019	Review of the current practices and inspection
Geology/Mineral Resources	SRK Consulting (U.S.), Inc.	August 10-13, 2021	Review of the current practices and inspection of laboratory and core facility, tour of pit geology, meetings and technical sessions on geological modeling.
Metallurgy/ Process	SRK Consulting (U.S.), Inc.	September 25, 2019	Review of the current practices and inspection
Separations Facility	SGS North America Inc.	January 11, 2022	Review of construction progress
Environmental/ Permitting/ Closure	SRK Consulting (U.S.), Inc.	No recent site visit	Visited site on several occasions under previous ownership

Source: SRK, 2022

2.5 Report Version Update

The user of this document should ensure that this is the most recent Technical Report Summary for the property.

This Technical Report Summary is not an update of a previously filed technical report summary filed pursuant to 17 CFR §§ 229.1300 through 229.1305 (subpart 229.1300 of Regulation S-K).

2.6 Units of Measure

The US System for weights and units has been used throughout this report. Tons are reported in short tons of 2,000 lb, drilling and resource model dimensions and map scales are in ft. All currency is in U.S. dollars (US$) unless otherwise stated.

2.7 Mineral Resource and Mineral Reserve Definitions

The terms “mineral resource” and “mineral reserves” as used in this Technical Report Summary have the following definitions.

Mineral Resources

17 CFR § 229.1300 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, 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

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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

17 CFR § 229.1300 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.

2.8 Qualified Person

This report was compiled by SRK Consulting (U.S.), Inc., with contributions from SGS North America Inc. and CRU International Limited. All three firms are third-party firms comprising mining experts in accordance with 17 CFR § 229.1302(b)(1). MP Materials has determined that all three firms meet the qualifications specified under the definition of qualified person in 17 CFR § 229.1300.

SGS North America Inc. prepared the following sections of the report.

• Sections 1.4.2 and 1.8.2 (Recommissioned Separations Facility)

• Section 10.4 (Separation of Rare Earth Elements)

• Section 14.6 (Individual Rare Earths Separations)

• Sections 18.1.2 and 18.1.5 (Separations Facility Capital Cost)

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• Section 18.2.2 (Separations Facility Operating Cost)

• Section 22.3.2 (Separations Facility)

• Related contributions to Section 1 (Executive Summary), Section 23 (Recommendations) and Section 24 (References)

In sections of this report prepared by SGS, references to the Qualified Person or QP are references to SGS North America Inc. and not to any individual employed at SGS.

CRU International Limited prepared the following sections of the report.

• Section 16 (Market Studies and Contracts)

• Related contributions to Section 1 (Executive Summary), Section 23 (Recommendations) and Section 24 (References)

In sections of this report prepared by CRU, references to the Qualified Person or QP are references to CRU International Limited and not to any individual employed at CRU.

SRK Consulting (U.S.) Inc. prepared all sections of the report that are not identified in this Section 2.8 as being prepared by SGS and CRU. In sections of this report prepared by SRK, references to the Qualified Person or QP are references to SRK Consulting (U.S.), Inc. and not to any individual employed at SRK.

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3 Property Description and Location

MP Materials’ surface ownership includes approximately 2,222 acres (900 hectares (ha)). The County of San Bernardino General Plan previously designated the Official Land Use District for the majority of the site as Resource Conservation. In 2021 a rezoning was completed, with the majority of the site designated for Regional Industrial (IR). The site is located within Improvement Overlay District 5, which applies to very rural areas with little or no development potential. The County Development Code permits mining in any land use district within the County subject to a conditional use permit.

The lands surrounding the Mountain Pass Mine site are mostly public lands managed by the Bureau of Land Management (BLM). The Mojave National Preserve, managed by the National Park Service, lies two to three miles to the north, west, and south of the site. The Clark Mountain Wilderness Area is located four miles northwest of the project site.

Current mining and mineral recovery operations include the following major activities and facilities at the mine site (Figure 3-1):

• A single open pit mine for extraction of the rare earth mineralization

• West and north overburden stockpiles (overburden consists of un-mineralized rock extracted from the pit)

• Crusher and mill/flotation plant

• Paste tailings disposal facility

• Mineral recovery plants (currently undergoing modification and recommissioning)

• Offices, warehouses, and support buildings

• Onsite evaporation pond facility

• Product storage

• Stormwater ponds

The primary mineral of economic interest mined historically at the Project is bastnaesite, a light brown carbonate mineral that is significantly enriched with 14 of the lanthanide elements plus yttrium.

As the Mountain Pass operation is currently configured, the material is crushed and blended at the crushing plant and then conveyed to the mill. At the mill, the crushed material is ground further with a ball mill and is conveyed via a slurry pipeline to the flotation plant to separate the bastnaesite from the gangue minerals. The primary product of the flotation process is a bastnaesite concentrate, which is filter-dried and then transported to customers for sale. Engineered containment facilities are used for storage of product and feedstock. Other ponds are used to control storm water runoff.

MP Materials is in the process of modifying and recommissioning a REE separations facility at Mountain Pass which, when placed into operation, will allow MP Materials to produce four saleable REE products: praseodymium and neodymium (PrNd) oxide, samarium, europium, and gadolinium (SEG+) oxalate, lanthanum (La) carbonate, and cerium (Ce) chloride.

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N 115.55 Property Line utility 35.483333°N Specialty Plant Gas Meter Site Shop/ Main Warehouse Maintenance Shop Administration Mobile Maintenance/ Warehouse Health/Safety Former Tailings Pund Warehouse Training Center Legacy Plant Open PIL Mine Separation Pa Crusher Tallings Plant Evaporation Fonds Northwest Tailings Disposal Facility West Overburden Stuckpile Warehouse

Source: MP Materials, 2021

Figure 3-1: General Facility Arrangement (WGS84 Coordinate System)

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3.1 Property Location

Mountain Pass is located in San Bernardino County, California, north of and adjacent to Interstate-15 (I-15), approximately 15 miles southwest of the California-Nevada state line and 30 miles northeast of Baker, California, at geographic coordinates 35°28’56”N latitude and 115°31’54”W longitude (Figure 3-2). This area is part of the historic Clark Mining District established in 1865. Mountain Pass is the only rare earth deposit identified within this district. The Project lies within portions of Sections 11, 12, 13, and 14 of Township 16 North, Range 14 East, San Bernardino Base and Meridian.

Re and High CLARK COUNTY Project Site COUNTY Nevado California KEEN COUNTY Visierelle ANGELES COUNTY RIVERSIDE COUNTY ORANGE

Source: Molycorp, 2010

Figure 3-2: Location Map

3.2 Mineral Title

Figure 3-3 illustrates the boundaries of the current mineral claims and surface rights associated with the Project, as provided by MP Materials. Mining claims and surface rights associated with the Project include:

• Patented claims with surface rights owned by MPMO and mineral rights held by SNR

• Unpatented lode and mineral claims held by SNR

• Surface ownership by MPMO and mineral rights controlled by the State of California

• Surface ownership by MPMO and mineral rights controlled by the U.S.

• Surface ownership by School District and mineral rights controlled by the U.S.

The rare earth mineralization at the Project is located within land owned by MP Materials.

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Historically, the surface and subsurface rights associated with the Project were held by Molycorp, Inc. (Molycorp), which filed for Chapter 11 bankruptcy protection in 2015. As part of the corporate restructuring in the bankruptcy proceedings, the former assets of Molycorp, associated with the Project, were split between multiple parties. This included MP Mine Operations LLC (MPMO), which purchased the real property (e.g., equipment, surface rights, water rights, surface use rights, access rights, easements, etc.) and SNR, which purchased the subsurface mineral rights and certain intellectual property. MPMO entered into a lease agreement with SNR on April 3, 2017, allowing MP Materials to extract rare earth products and byproducts from the Project mineral rights (note that this agreement excludes rights to all other minerals and hydrocarbons that could be present at the Project) and utilize the intellectual property, held by SNR. At the time of entering into the lease agreement, MPMO and SNR had shareholders common to both entities; however, they were not partners in business nor did they hold any other joint interest. On November 17, 2020, MPMO and SNR were combined with Fortress Value Acquisition Corp. (FVAC) and became wholly-owned subsidiaries of FVAC, which was in turn renamed MP Materials Corp. Consequently, the intercompany transactions between MPMO and SNR did not continue after the business combination.

Discussion of each category of land ownership is provided in the following sections. Figure 3-3 provides a land tenure map. Listings of claims for MPMO and SNR as reflected on the Bureau of Land Management (BLM) website are located in Appendix A to this Technical Report Summary.

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11 29 34 MOUNTAIN PASS RARE EARTHO DISTR CLAIM AND PROPERTY MAP 5 22 36 18 16 15 19 20 21 22 29 28 27 32 33 34 21 22 27 34 2 31 25 26 21 22 23 15 10 3 34 36 1

Source: Chevron, 2007

Figure 3-3: Land Tenure Map

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3.2.1 Nature and Extent of Registrant’s Interest

Surface Ownership by MP Materials and Mineral Rights by the State of California

The California State Lands Commission (CSLC) retains a mineral right in T16N, R14E, Section 13 (Figure 4-2). In a June 19, 2003, letter from the CSLC letter to the previous Project owner, “...the CSLC has advised San Bernardino County that the State acquired and patented certain lands within the proposed project boundary, reserving a 100% mineral interest in approximately 400 acres in the S1/2, SE1/4 of NE1/4, and the SW1/4 of the NW1/4 of Section 13, T16N, R13E, SBM. This interest is under the jurisdiction of the CSLC.” (CSLC, 2003).

Surface Ownership by MP Materials and Mineral Rights by the U.S. Government

The U.S. government holds the mineral rights to an approximate 2.25 square mile parcel of land located east of the planned area of operations.

Surface Ownership by School District and Mineral Rights by the State of California

The School District owns a 40-acre parcel of land adjacent to the Bailey Road highway exit. The State of California retains the mineral rights to this parcel. This mineral right is located to the south of the existing deposit and does not encroach on the ultimate boundaries of the open pit or overburden stockpiles. MPMO has entered into a lease with the School District for this parcel excluding those areas covered by the legacy school assets.

3.3 Royalties, Agreements, and Encumbrances

Several public service and utility easements and rights-of-way are located within the mine boundaries, including a Southern California Edison (SCE) electric utility easement and an AT&T right-of-way.

3.4 Environmental Liabilities and Permitting

MP Materials maintains financial assurance cost estimates for closure, PCM, and AKRFR for current and planned operations at the Mountain Pass property. The LRWQCB administers the groundwater and surface water related financial assurance obligations. San Bernardino County administers financial assurance requirements for surface reclamation of the property. The California Department of Resource, Recycling and Recovery administers financial assurance requirements for decontamination and decommissioning activities. MP Materials maintains miscellaneous financial assurance instruments for other closure-related obligations. Table 3-1 presents the current financial assurance obligations for the Mountain Pass property. The total financial assurance obligation is approximately US$39 million.

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Table 3-1: Current Financial Assurance Obligations

Regulatory Authority	Regulatory Obligation	FA Instrument	FA Instrument (US$)
Lahontan Regional Water Quality Control Board	Closure	Bond #K09652437	13,266,445
	Post-Closure	Bond #K09652449	4,217,681
	AKRFR	Bond #K09652450	8,759,632
County of San Bernardino	Closure – Physical Grading, Capping, Vegetating and Monitoring	Bond #K09652504	10,233,989
	Closure and Regrading of NW Evaporation Ponds	Bond #K09652498	723,100
California Department of Resource, Recycling and Recovery	Closure – Landfill Post-Closure Monitoring	Bond #SUR0059731 Trust Agreement	327,285 123,214
California Department of Public Health – Radiological Health Branch	Closure – Decommissioning of Industrial Facilities	Bond #K09652474	1,125,000
Bureau of Land Management	Fresh Water Wells ROW		191,200
State Lands Commission	Fresh Water Pipeline ROW		20,000
Total			$38,987,546

Source: MP Materials, 2021

Existing closure obligations include:

• Reclamation and closure of the existing overburden stockpiles and dry stack tailings facility

• Decommissioning of existing industrial facilities (e.g., the modified separations facility) in accordance with the approved Mine Reclamation Plan

• Completing active Corrective Action Programs (CAP) for groundwater remediation

• Clean closure of the on-site evaporation ponds

• Indirect costs associated with direct costs listed above

Existing post-closure obligations include annual inspection and maintenance for the following closed facilities:

• Pond P-1

• Pond P-16

• Community landfill

3.4.1 Remediation Liabilities

The AKRFR costs include approximately 20 years of ongoing groundwater extraction and treatment of a plume of impacted groundwater generated during historic operations. Pursuant to a 1998 clean up and abatement order issued by the LRWQCB, previous ownership conducted, and MP Materials continues to conduct various investigatory, monitoring, and groundwater abatement activities related to contamination at and around the Mountain Pass facility. These activities include soil remediation and the operation of groundwater monitoring and recovery wells, water treatment systems, and evaporation ponds.

3.4.2 Required Permits and Status

MP Materials holds conditional use and minor use permits from SBC, which currently allow continued operations of the Mountain Pass facility through 2042. MP Materials also holds permits to operate from

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the LRWQCB and the Mojave Desert Air Quality Management District. The Company plans to re-start the REE separations facility with some modifications to the process. The Company maintains the current permit authorization to operate the NWTDF and to co-dispose of other waste streams in the NWTDF. MP Materials anticipates these waste streams will meet the approved waste characterization profiles.

The updated mine plan extends mining through 2056. MP Materials will be required to amend the conditional use permit from SBC to accommodate the updated mine plan. Section 17.2 provides further information.

3.5 Other Significant Factors and Risks

Full extraction of this reserve is dependent upon modification of current permitted boundaries. Failure to achieve modification of these boundaries would result in MP Materials not being able to extract the full reserve estimated in this study. It is MP Materials’ expectation that it will be successful in modifying this permit condition. In SRK’s opinion, MP Materials’ expectation in this regard is reasonable.

A portion of the pit encroaches on an adjoining mineral right holder’s concession. This portion of the pit only includes waste stripping (i.e., no rare earth mineralization is assumed to be extracted from this concession). The prior owner of Mountain Pass had an agreement with this concession holder to allow this waste stripping (with the requirement that aggregate mined be stockpiled for the owner’s use). MP Materials does not currently have this agreement in place, but SRK believes it is reasonable to assume MP Materials will be able to negotiate a similar agreement.

SRK is not aware of any other risk items that can reasonably be assumed to impact access, title, right, or ability to perform work on the property.

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4 Accessibility, Climate, Local Resources, Infrastructure, and Physiography

The Project is located in San Bernardino County, California, north of and adjacent to Interstate 15 (I-15), approximately 15 miles southwest of the California-Nevada state line and 30 miles northeast of Baker, California (Figure 3-2).

4.1 Topography, Elevation, and Vegetation

The area is in the southwestern part of the Great Basin section of the Basin and Range physiographic province, which is characterized by a series of generally north to south-trending mountain ranges separated by broad, low-relief alluvial basins, which often have internal drainage (Peterson, 1981).

The Project occupies the highest elevation along I-15 between Barstow, California, and Las Vegas, Nevada. Elevations range from 4,500 to 5,125 feet (ft) above mean sea level (amsl), with most of the site located between 4,600 to 4,900 ft amsl. Clark Mountain (located northwest of the Project) is the highest local peak at 7,903 ft amsl.

The major habitat in the Project area is Mojave Desert scrub. Local surface drainages support a mixture of scrub and riparian species. Vegetation is characterized by various yuccas with a predominance of Eastern Joshua trees, larger shrubs, thorn bushes, and a host of smaller shrubs. Areas of ongoing disturbance in the Project area are barren of vegetation.

4.2 Accessibility and Transportation to the Property

The nearest major city is Las Vegas, Nevada, located 50 miles to the northeast on I-15. The Project lies immediately north of I-15 at Mountain Pass and is accessed by the Bailey Road Exit (Exit 281 of I-15), which leads directly to the main gate. The mine is approximately 15 miles southwest of the California-Nevada state line in an otherwise undeveloped area, enclosed by surrounding natural topographic features. I-15 follows the natural drainages, east-west between the Clark Mountain and Mescal mountains ranges, cresting at Mountain Pass Summit at an elevation of 4,730 ft amsl.

All access to the Project is controlled by MP Materials, and there is no public access through the Project area. All public access roads that lead to the Project are gated at the property boundary.

MP Materials maintains the existing infrastructure for the Project in support of mining and processing activity. A manned security gate is located on Bailey Road for providing required site-specific safety briefings and monitoring personnel entry and exit to the Project.

4.3 Climate and Length of Operating Season

The climate at Mountain Pass is described as arid desert, generally hot and dry in the summer and mild in the winter, with limited precipitation and cloud cover. Based on Western Regional Climate Center Statistics, the coldest month of the year is January with an average minimum temperature of 29.5°F (-1.4°C). The warmest month is July with an average high temperature of 92.8°F (33.8°C).

Precipitation in the area of the mine averages 8.4 inches per year. The maximum precipitation from a single storm in the past 45 years was 5.9 inches (Geomega, 2000). Most storms yield a precipitation of 0.5 inch or less. Precipitation most frequently occurs during November through February, accounting for over 40% of the annual total rainfall. However, the most significant portion of the annual rainfall can

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occur as summer thunderstorms during July and August with average monthly precipitation above 1.0 inch per month during these two months. These storms may result in heavy rainfall and flash floods. The snowfall in the winter months can accumulate rapidly but has minimal effect on operations. Operations at the Project are year-round.

4.4 Infrastructure Availability and Sources

MP Materials has fully developed operating infrastructure for the Project in support of extraction and concentrating activities. A manned security gate is located on Bailey Road for providing required site-specific safety briefings and monitoring personnel entry and exit to the Project.

Given the relative proximity of the Project to the city of Las Vegas, Nevada, most personnel at the Project commute from the greater Las Vegas area. This regional city provides an adequate source of skilled and unskilled labor for the operation.

Outside services include industrial maintenance contractors, equipment suppliers, and general service contractors. Access to qualified contractors and suppliers is excellent due to the proximity of population centers, such as Las Vegas, Elko, Nevada (an established large mining district), and Phoenix, Arizona (servicing the copper mining industry).

Power to the Mountain Pass facility is currently supplied by a 12-kV line from a Southern California Edison substation two miles away. The mine historically met thermal demands of the process circuit through use of boilers running on fuel oil, diesel, and propane. Development activities completed by the prior Project owner included the construction of a Combined Heat and Power (CHP) or co-generation (cogen) power facility to address the increased electrical demands associated with the process flow sheet utilized at that time. This CHP plant is in the final stages of being recommissioned and will provide for all the electricity and steam needs for all process areas of the site starting in early 2022.

Water is supplied through active water wells located eight miles west of the Project. Fire systems are supplied by separate fire water tanks and pumps.

Site logistics are straightforward with the current concentrate product currently shipped in Super Sacks within a shipping container by truck approximately 4.5 hours to the port of Los Angeles. At the port, the containers are loaded onto a container ship and shipped to the final customers.

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5 History

5.1 Prior Ownership and Ownership Changes

The Molybdenum Corporation of America (MCA) purchased the Birthday claims and the Sulfide Queen properties in 1950 and 1951, respectively. In 1974, MCA changed its name to Molycorp, Inc. (“Old Molycorp”). In 1977, Union Oil of California (Unocal) purchased Old Molycorp and operated the company as a wholly-owned subsidiary. In 2005, Chevron Corporation purchased Unocal. On September 30, 2008, Chevron sold the Mountain Pass facility and Rare Earth business, including the rights to the name Molycorp, to a private investor group who formed Molycorp, LLC. Molycorp, Inc. (“Molycorp”) was formed on March 4, 2010, for the purpose of continuing the business of Molycorp, LLC in corporate form. Molycorp filed for Chapter 11 bankruptcy protection in June 2015. As part of the corporate restructuring in the bankruptcy proceedings, the former assets of Molycorp associated with the Project were split between multiple parties. This included MPMO, which purchased the real property (e.g., equipment, surface rights, water rights, surface use rights, access rights, easements, etc.) and SNR, which purchased the subsurface mineral rights and certain intellectual property.

MPMO entered into a lease agreement with SNR on April 3, 2017, allowing MP Materials to extract rare earth products and byproducts from the Project mineral rights (note that this agreement excludes rights to all other minerals and hydrocarbons that could be present at the Project) and utilize the intellectual property, held by SNR. At the time of entering into the lease agreement, MPMO and SNR had shareholders common to both entities; however, they were not partners in business nor did they hold any other joint interest. On November 17, 2020, MPMO and SNR were combined with FVAC and became wholly-owned subsidiaries of FVAC, which was in turn renamed MP Materials Corp. Consequently, the intercompany transactions between MPMO and SNR did not continue after the business combination.

5.2 Exploration and Development Results of Previous Owners

The mining history of the area began with the organization of the Clark Mining District in 1865. This district produced about US$5,000,000 in silver between 1865 and about 1895 (Olson et al., 1954). Between 1900 and 1920, many small lead, zinc, copper, gold, and tungsten mines were operated in the area.

Mining at Mountain Pass began in 1924 when prospectors identified galena (lead sulfide) on Sulfide Queen Hill, which is near the location of the existing open pit. Several small shafts and trenches were excavated by various operators; however, no ore was shipped. The Sulfide Queen mine was developed and worked for gold between 1939 and 1942, producing about 350 ounces of gold from an inclined shaft about 320 ft deep and about 2,200 ft of workings developed on four levels.

The discovery of rare earth mineralization at Mountain Pass was made in April of 1949 by prospectors searching for uranium. Having noted that samples from the Sulfide Queen gold mine were radioactive, prospectors returned to the area and discovered a radioactive vein containing a large proportion of a light brown mineral (bastnaesite) that the prospectors were unable to identify. This original discovery is known as the Birthday vein. The prospectors sent a sample of the unknown mineral to the United States Bureau of Mines for identification.

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The USGS confirmed the bastnaesite discovery and made a public announcement in November 1949 (Olson et al., 1953). This attracted the attention of several mining companies, including MCA, which purchased the Birthday group of claims in February 1950. MCA sank a 100 ft-deep shaft on the Birthday claims, but no mineable ore was delineated, and development was stopped.

During this time, prospectors identified carbonatite dikes throughout a wider, adjacent area. The USGS proceeded to conduct detailed mapping of the entire Mountain Pass area. During this work, the USGS staff identified a massive body of carbonatite to the south of the Birthday claims, largely made up of barite, calcite, dolomite, and bastnaesite. Much of this carbonatite body was located on the original Sulfide Queen claims. MCA bought the Sulfide Queen claim group and the surrounding properties in January 1951. The existing gold mine and its associated equipment and buildings were also purchased, and a new crushing plant was installed. MCA drilled several hundred shallow churn holes in the following months and analyzed the cuttings for their rare-earth element contents (Olson et al., 1954).

Production of rare earth concentrate at the Project began in 1952, using the old gold plant, a new ball mill, and flotation cells from MCA’s Urad, Colorado, molybdenum property. Mining started on a portion of the deposit where the ore averaged more than 15% TREO. The production rate varied from 80 to 120 st per day.

MCA signed a contract with the U.S. General Services Administration to produce rare earth concentrates for the government stockpile. By 1954, MCA shipped one hundred and twenty 60 t carloads of bastnaesite concentrate to the government stockpile, thereby fulfilling the terms of the contract. Other markets for TREOs had not yet developed, and the mine and mill operated part-time with a small crew.

Owing to the increasing demand for europium for use in color televisions, MCA constructed a europium oxide plant in 1965 and increased production six-fold from the previous year to approximately 6.1 million pounds (Mlb) of TREO concentrate. The following year, a new concentrator was completed with a capacity of 600 metric tonnes per day. At the start of 1965, MCA produced 6,000 pounds per year (lb/yr) of europium oxide. By year-end, production of europium oxide reached 20,000 lb/yr. By the end of 1966, total production at the Project had quadrupled to 24 Mlb/yr of TREO concentrates.

Old Molycorp (formerly MCA) undertook a major geologic evaluation program at Mountain Pass between 1976 and 1980. MCA and Old Molycorp drilled dozens of diamond drillholes between 1953 and 1992 for exploration, mine development, and condemnation. More than 300 new mining claims were added over ground which could potentially contain rare earth mineralization. Regional aeromagnetic and radiometric surveys were conducted within and beyond the known rare earth mineralization, and Landsat imagery for the region was evaluated. The geological program included characterization of the alkaline rocks and rare earth mineralization of the district and involved detailed geologic mapping and petrographic studies of the Sulfide Queen deposit and the surrounding rocks. Ground-based geophysical surveys were completed over the known bastnaesite-bearing carbonatite and associated intrusive rocks.

Due to the continued expansion of the rare earths market, a new separation plant was completed in 1982, which could produce samarium and gadolinium oxides up to 99.999% in purity by solvent extraction (SX). Subsequently, the plant was modified to produce high-purity terbium oxide for fluorescent lighting.

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In 1989, Old Molycorp began production of dysprosium oxide and increased its output of neodymium to satisfy the demand created by the growing neodymium-iron-boron permanent magnet industry. By 1990, lanthanide processing facilities at Mountain Pass expanded to produce various TREO concentrates. Between 1995 and 1997, Molycorp produced and sold in excess of 40 Mlbs of rare earth oxide products per year. Limited mining of overburden and mineralized rock took place through 2002. The historic mill entered care and maintenance in 2002. Between 2007 and 2012, there was limited production of rare earth oxides from various types of stockpiled rare earth concentrates (primarily lanthanum concentrates and bastnaesite concentrate) through the historic separation facility.

In December 2010, under the new Molycorp, mining operations were restarted, and in January 2011, a major redevelopment project was initiated targeting modernization of milling and separation facilities. These new mining and separation facilities were intended to be developed in two phases, with the first phase targeting 19,050 metric tonnes (42 Mlb) of rare earth production per year and the second phase targeting 40,000 metric tonnes (88 Mlb) of rare earth production per year. This modernization included construction of a new mill, cracking facilities, separation facilities, and associated infrastructure, including power generation and reagent recycling facilities. The new separation facilities included production of cerium, lanthanum, neodymium, and praseodymium, with the remaining rare earths sold as a samarium, europium, and gadolinium (SEG) concentrate. During initial construction activities, Molycorp changed its development strategy and decided to build out capacity for both phases at the same time. Construction activities were largely completed by the end of 2013, with all first phase equipment constructed and most of the second phase constructed. Ramp up of the concentrator, separation facility and associated infrastructure (e.g., chlor-alkali/reagent recycling) encountered several issues that limited production and prevented operations from achieving targeted goals. 2013 production from Mountain Pass was approximately 7.7 Mlb of rare earth oxides, and 2014 production was approximately 10.5 Mlb. January through June 2015 production was approximately 8.1 Mlb of rare earth oxides. Molycorp declared bankruptcy in June 2015, and mining and processing operations were halted at that time.

The current operator, MP Materials, restarted mining and milling operations in December 2017. MP Materials does not currently separate individual rare earths and instead sells a bastnaesite concentrate. 2018 production totaled approximately 29,400 metric tonnes of concentrate with approximately 13,900 metric tonnes contained rare earth oxides. 2019 production totaled 58,535 metric tonnes of concentrate with approximately 28,442 metric tonnes contained rare earth oxides. 2020 production totaled 69,430 metric tonnes of concentrate with approximately 38,561 metric tonnes contained rare earth oxides. The most recent nine months of production (January through September 2021) totaled 57,154 metric tonnes concentrate production with 32,152 metric tonnes contained rare earth oxide.

5.3 Historic Production

The reported historic production for the Mountain Pass deposit for the period 1953 through 1970, including the tonnage of mineralized and overburden materials mined, the plant feed grades and recovery, and pounds of rare-earth oxides produced, is shown in Table 5-1. The historic production from 1968 to 2002, including short tons mined, crushed, and milled, is presented in Table 5-2. Historic rare earth oxide production from 2009 to 2015, which includes reprocessing of existing stockpiles (2009 to 2012) and processing of freshly mined ore (2012 to 2015), is presented in Table 5-3. MP Materials’ historic rare earth oxide production from 2018 through May 2020 is presented in Table 5-4.

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Table 5-1: Production History, 1952 to 1970

Item	1952 to 1964	1965	1966	1967	1968	1969	1970	(1)	Total
Waste stripped, st	0	0	0	15,000	20,000	85,000	14,000		134,000
Ore mined and fed to plant, st	255,375	37,476	179,721	201,233	193,100	259,097	182,290		1,308,292
Flotation Plant Feed, % TREO	9.1	10.2	9.1	8.3	8.1	7.5	7.2		8.3
Concentrate No. 400, klb TREO	31,934	6,094	12,873	16,483	2,361	2,188	7,519		154,444
Concentrate No. 401, klb TREO	0	0	11,139	8,001	20,408	25,155	10,289		0
Flotation Plant Recovery, %	68.6	80.1	73.0	73.2	72.7	70.5	68.1		0
Chemical Plant Feed, klb TREO	0	6,899	18,380	13,198	14,087	19,604	11,178		83,346
RE Oxide Nos. 410/411, klb TREO	0	275	282	307	1,731	409	0		3,004
Cerium Nos. 530/532, klb CeO	0	0	1,925	1,668	1,680	1,901	1,672		8,846
Lanthanum, 521, klb TREO	0	0	0	3,250	6,669	7,568	5,522		23,009
Lanthanum, 523, klb TREO	0	0	306	501	249	28	64		1,148
Neo-Praseo No. 545, lb Pr6O11	0	0	0	0	0	74,702	3,677		78,379
Gadolinium No. 573, lb Gd2 O	0	0	0	0	17,084	17,881	13,990		48,955
Gad-Sam No. 575, lb TREO	0	0	0	9,961	12,095	0	0		22,056
Samarium No. 583, lb Sm2 O3.	0	0	0	0	29,600	0	0		29,600
Europium Nos. 500/501/ 510/510B/511, lb	0	1,845	11,384	9,058	3,234	7,847	8,226		41,594

Source: Mountain Pass monthly operational reports

⁽¹⁾: Through October 31, 2007

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Table 5-2: Mine Production History, 1971 to 2002

Year	Mined (st)		Crushed (st)		Milled (st)		Overburden (st)
1971		214,000		181,175		181,175		No data
1972		163,000		228,488		228,488		No data
1973		303,000		305,072		305,073		No data
1974		479,000		499,597		499,596		9,100
1975		296,693		296,693		296,693		70,100
1976		355,253		308,938		308,938		73,980
1977		314,946		321,508		321,508		66,255
1978		292,760		266,757		266,757		132,200
1979		326,010		358,399		358,399		327,760
1980		386,927		360,068		360,068		219,345
1981		371,553		370,207		370,207		225,691
1982		400,428		400,427		391,417		221,625
1983		485,315		322,771		371,252		226,000
1984		621,714		439,000		543,354		728,000
1985		365,000		204,000		253,000		1,233,000
1986		343,000		214,000		225,000		1,225,000
1987		402,000		320,000		358,000		1,072,000
1988		143,000		214,000		221,764		1,049,000
1989		445,000		419,000		418,446		1,610,000
1990		706,000		508,000		480,161		1,749,000
1991		404,000		446,000		336,344		2,477,000
1992		275,000		247,000		409,000		1,771,000
1993		540,000		447,000		433,000		1,232,000
1994		567,000		494,000		508,000		1,217,000
1995		714,000		546,000		537,000		2,388,000
1996		604,000		551,000		544,000		2,312,000
1997		632,000		452,000		424,000		3,355,000
1998		234,000		269,000		321,000		688,000
1999		94,000		0		0		43,000
2000		78,000		0		0		239,000
2001		175,010		260,000		175,010		634,000
2002		201,520		217,204		183,487		255,520

Source: Mountain Pass monthly operational reports

Mill quantities do not include tailings that were reprocessed.

Between 1975 and 1982, crushing tonnages were not recorded (assumed to be the same as milling tonnages).

Table 5-3: Mountain Pass Production History, 2009 to 2015, as Separated RE Products

Year		TREO Production (Metric Tonnes)
	2009		2,103
	2010		1,296
	2011		3,062
	2012		2,236
	2013		3,473
	2014		4,769
	2015(1)		3,678

Source: Molycorp 10-K and 10-Q filings

⁽¹⁾: January to June production

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Table 5-4: Mountain Pass Production History, 2018 to 2021, as Bastnaesite Concentrate

Year	TREO Production (Metric Tonnes)
2018	13,913
2019	28,442
2020	38,561
2021(1)	32,152

Source: MP Materials

⁽¹⁾: January to September production

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6 Geological Setting, Mineralization and Deposit

6.1 Regional Geology

Mountain Pass is located in the southern part of the Clark Range in the northern Mojave Desert. The Mojave is situated in the southwestern part of the Great Basin which extends from central Utah to eastern California and is characterized by intense Tertiary regional extensional deformation. This deformational event resulted in north-south trending mountain ranges separated by gently sloping valleys, characteristic of Basin and Range tectonic activity. The Mountain Pass rare earth deposit is located within an uplifted block of Precambrian metamorphic and igneous rocks that is bounded to the south and east by basin-fill deposits in the Ivanpah Valley. This block is separated from Paleozoic and Mesozoic rocks on the west and southwest by the Clark Mountain fault, which strikes north-northwest and dips from 35° to 70º west but averages 55 Wº. The North Fault forms the northern boundary of the block, striking west-northwest and dips from 65° to 70° south (Olson, et al., 1954; Castor, 2008). Geology of Mountain Pass is shown in Figure 6-1.

There are two main groups of rocks in the Mountain Pass area divided by age and rock type. These are Early Proterozoic high-grade metamorphic rocks, which are intruded by unmetamorphosed Middle Proterozoic ultrapotassic and carbonatite rocks. The Early Proterozoic high-grade metamorphic complex represents a wide variety of compositions and textures, as follows:

• Garnetiferous micaceous gneiss and schist

• Biotite-garnet-sillimanite gneiss

• Hornblende gneiss, schist, and amphibolite

• Biotite gneiss and schist

• Granitic gneiss and migmatite; granitic pegmatite

• Minor occurrences of foliated mafic rocks

The Middle Proterozoic ultrapotassic rocks are intrusive bodies of granite, syenite, and composite shonkinite-syenite, which contain augite and orthoclase. These have been intruded by carbonatites which formed swarms of thin dikes, stocks and the tabular Sulfide Queen carbonatite at the Project (Olson et al, 1954; Castor 2008). The Middle Proterozoic ultrapotassic rocks have been age dated using U-Th-Pb and ⁴⁰Ar^-39Ar methods at 1,410 ± 5 Ma and 1403 ± 5 Ma for shonkinite and syenite respectively. The rare earth-bearing carbonatite units, including the Sulfide Queen deposit, are younger with age dates, using Th-Pb ratios, of 1,375 ± 5 Ma (DeWitt et al, 1987). Both the Early Proterozoic metamorphic rocks and the Middle Proterozoic intrusive rocks have been crosscut by volumetrically minor, Mesozoic to Tertiary age dikes of andesitic to rhyolitic composition. Large portions of the Mountain Pass district are covered by younger (Tertiary to Quaternary) basin-fill sedimentary deposits (Olson et al, 1954; Castor 2008) (Figure 6-1).

Significant rare earth mineralization is only associated with the carbonatite intrusions. Strongly potassic igneous rocks of approximately the same age are known from other localities in and around the Mojave Desert, but no significant carbonatite bodies or rare earth mineralization have been identified (Haxel, 2004).

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1,4800 1 inch = 400 fit P-16

Source: Geomega, 2012

Figure 6-1: Regional Geological Map

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6.2 Local and Property Geology

At Mountain Pass, the ultrapotassic rocks occur in seven larger stocks and as hundreds of small dikes. The largest single body is a composite shonkinite-syenite-granite stock approximately 6,400 ft in length and 2,100 ft wide (Olson et al, 1954). These rocks span a variety of compositions, from phlogopite shonkinite (melanosyenite) to amphibole-biotite (mesosyenite and leucosyenite) to alkali-rich granite (Haxel, 2004). These complex and varied lithologies are believed to be sourced from the same parent magma formed from partial melting of the upper mantle (asthenosphere) beneath the North American continent during the Middle Proterozoic. The different compositions reflect different phases of magma differentiation (Castor, 2008). A generalized geologic map of the area is shown in Figure 6-2.

The Sulfide Queen carbonatite, which hosts the mineralization at the Project is referred to as a stock but is a roughly tabular, sill-like body that strikes approximately north and dips to the west at about 40° as shown in Figure 6-3. The carbonatite magma is believed to have formed by liquid immiscibility, separating from the same parent magma which formed the ultrapotassic rocks occurring nearby (Castor, 2008).

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Bastnäsite Beforsite (bb) Bastbäsite Dolosövite (bd) Bastnäsite Sövite (bs) Monazite Carbonatite (mc) Breccia (bx) Gneiss and Schist (gn) 85 80 A’ - 35.4800° N NA B’ 50 m 115.5300 W

Source: Castor, 2008

Figure 6-2: Generalized Geologic Map – Sulfide Queen Carbonatite

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bs bs gn mc ds bs 4670 level Drill Hole Bastnäsite Beforsite (bb) Bastnäsite Dolosövite (bd) Bastnäsite Sövite (bs) Monazite Carbonatite (mc) Breccia (bx) Gneiss and Schist (gn)

Note: Section looking N-NE

Source: Castor, 2008

Figure 6-3: Schematic Cross Section (A-A’) of Sulfide Queen Carbonatite

6.2.1 Local Lithology

In the open pit and to the south, east and west, lithology is dominated by gneiss and the Sulfide Queen carbonatite. Immediately north of the pit, carbonatite is found at surface and a small outcrop of syenite is found adjacent to and on the east flank of the Sulfide Queen. The Sulfide Queen extends to the contact with shonkinite and ultrapotassic granite approximately 650 ft northwest of the open pit boundary.

The carbonatite rocks at the Project have been divided by geologists at Mountain Pass into six types:

• Bastnaesite sövite (Bastnaesite-barite sövite)

• Bastnaesite beforsite (Bastnaesite-barite sövite)

• Bastnaesite dolosövite (Bastnaesite-barite dolomitic sövite)

• White sövite (White bastnaesite-barite sövite)

• Parisite sövite (Parisite sövite)

• Monazitic sövite (Monazite-bearing carbonatite)

These divisions are based on the carbonate mineral composition of the carbonatite, either calcite or dolomite, the dominant rare earth mineral, texture and other criteria detailed in the following sections

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(Castor 1988, 2008). The different carbonatite types and their specific mineralization are discussed in detail in Section 6.3.

Breccia is found within and adjacent to the Sulfide Queen and includes altered clasts of country rock as well as carbonatite. It is most abundant in the northern part of the open pit and to the south under the former mill. Breccia textures range from matrix to clast supported breccia with rounded to angular clasts. In the hanging wall of the Sulfide Queen, breccia occurs as a stockwork while in other areas it appears to have formed by intrusive stoping. In the footwall of the carbonatite, the breccia is composed of rounded and crushed gneiss, syenite and shonkinite, which is interpreted by Castor (1988, 2008) as indicating a pre-carbonate intrusive formation. Breccia has previously been thought to be unmineralized but contains monazite in places.

6.2.2 Alteration

Alteration at the Property is primarily contact metamorphism associated with the emplacement of the Sulfide Queen carbonatite. It is primarily fenitic alteration and found in the country rock adjacent to the carbonatite. Fenitic alteration or fenitization is associated with carbonate-rich fluids and is characterized by secondary potassium feldspar, phlogopite and magnesio-riebeckite with chlorite and hematite in places. Owing to the resulting distinctive color and textures of these minerals, the fenitic alteration type is relatively easy to recognize in outcrop and drill core by its light-colored minerals. Fenitization is typically less intense and widespread proximal to the ultrapotassic rocks relative to the intense alteration observed in the more reactive Middle Proterozoic rocks in the open pit area (Castor, 1988, 2008).

Other alteration identified locally, includes hydrothermal alteration and silicification around the Celebration Fault. This is considered late stage and has little effect on mineralization (Castor, 1988; 2008).

The presence of sillimanite in the biotite-garnet-sillimanite gneiss indicates that rocks of the Middle Proterozoic age reached high temperatures and pressures during metamorphism and were metamorphosed to the granulite facies. The carbonatite sills are not metamorphosed, and the Late Proterozoic age ultrapotassic rocks show limited contact metamorphism where these rocks host carbonatite.

6.2.3 Structure

Structural controls include local brecciation and faulting. Regional structural controls include the Clark Mountain and North Faults, which bound the block separating the Proterozoic rocks at the Property from the surrounding Paleozoic and Mesozoic age rocks. The Clark Mountain Fault strikes north-northwest and dips from 35° to 70º W but averages 55º W. The North Fault strikes west-northwest and dips from 65° to 70º S and has offset the Clark Mountain Fault by an estimated 1,200 ft near the Property. In general, all major faults in the Property area strike north-westerly and dip to the southwest. This includes the Middle and South Faults near the open pit (Olsen et al, 1954; Castor, 2008).

Within the open pit area, the important faults are the Ore Body, Middle and the Celebration faults. The Ore Body Fault is a splay off of the North Fault and the carbonatite and ultrapotassic rocks are found primarily between the Middle and Ore Body Faults. Both of these are normal faults that strike northwest and dip moderately to steeply southwest. Both faults display evidence of left-lateral and dip-slip displacements and were active until the Pliocene-Pleistocene. Both faults contain substantial gouge

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zones and are barriers to groundwater flow. Many smaller faults with similar orientations and movement histories have been mapped between these two faults.

The Celebration Fault transects the open pit along the highwall and dips into the pit. It also functions as a groundwater conduit and is a target for two dewatering wells. This structure is sub-parallel to the Middle Fault and strikes at an average of N60º W with a dip of approximately 60° SW. Although appreciable dip-slip offset is not noted north of 800 NW on the mine grid, shallowly plunging slickensides indicate a component of right lateral strike-slip motion. The Celebration Fault is marked by a 10 to 20 ft wide zone of shearing and brecciation with only local cementation. The Friendship Fault visible in the pit dips approximately 78º NE and is considered to be a splay off the Celebration Fault. Information from drilling indicates that the Sulfide Queen carbonatite has offset downdip by a series of faults with limited displacement. These structures are sub-parallel to the Friendship Fault, do not offset the Celebration Fault and displacement of the Sulfide Queen carbonatite is less than 100 ft in most places (Castor, 1988; Molycorp, 2003; Nason, 2009).

6.3 Significant Mineralized Zones

Mineralization occurs entirely within the Sulfide Queen carbonatite within the Project area. This has been defined through drilling and mapping. Grade distribution internal to this mineralized zone is variable. Higher grade zones (>10% TREO) tend to occur in lenses parallel to the hangingwall/footwall contacts, both downdip and along strike. They also occur along faults which have different orientations; meteoric water in faults dissolved host carbonate minerals leaving behind a higher concentration of bastnaesite in a weathered host rock. Continuity of mineralization internal to the carbonatite zone is well defined both along strike and downdip.

The currently defined zone of rare earth mineralization exhibits a strike length of approximately 2,750 ft in a north-northwest direction and extends for approximately 3,000 ft downdip from surface. The true thickness of the >2.0% TREO zone ranges between 15 to 250 ft.

The principal economic mineral at the Project is bastnaesite, a rare earth fluorocarbonate with the generalized chemical formula LnCO₃F, where Ln is a variable representing a lanthanide elemental component (usually lanthanum or cerium). This naming convention is applied throughout this resource report. The bastnaesite composition at the Project is dominated by cerium, lanthanum, and neodymium, with smaller concentrations of praseodymium, europium, samarium, gadolinium, dysprosium, terbium and the heavier rare-earth elements.

Bastnaesite mineralization at the Project is entirely restricted to carbonatite rocks and its nearby breccia which were subdivided by Castor (1988, 2008) as described below. Non-mineralized rock types within the open pit area are also described.

Bastnaesite Sövite

Bastnaesite-sövite is a calcite-rich mineralized rock type containing relatively coarse, early-formed bastnaesite, along with recrystallized barite phenocrysts, in an anhedral matrix of fine calcite and barite. Where unaltered, this material is a pink to mottled white and red-brown rock carrying about 65% calcite, 25% strontian barite, and 10% bastnaesite. However, chemical and mineralogic changes subsequent to crystallization have produced more complex mineralogy. The sövite is characterized by relatively high calcium, strontium and lead, moderate barium and low phosphorous.

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The bastnaesite sövite forms the basal portions of the resource area, and all of the resource at the north end of the pit. At the south end of the pit, sövite makes up less than half the mineralized zone thickness.

Celestite occurs in the bastnaesite sövite as bladed replacements and outgrowths from barite phenocrysts. Celestite is particularly abundant, along with variable amounts of very coarse bastnaesite, in a basal sheet of otherwise unaltered sövite about 50 ft thick. This celestite sövite zone is separated from the main mineralized body by a zone of gneiss and/or breccia. Late celestite veins have been observed cutting talc-altered sövite.

Dark brown or ochre limonite is locally pervasive in sövite, particularly in silicified ore. Such rocks rarely have higher iron contents than unaltered sövite. Coarse bastnaesite typifies sovitic mineralized rock. On the 4640 level the average bastnaesite grain diameter is about 300 µm. For the most part, monazite [LNPO₄)] occurs sparingly in the sövite, almost always as small primary euhedral and patches of radial secondary needles.

Bastnaesite Beforsite

The bastnaesite beforsite unit generally lies above the sovitic material and is separated from it by dolosovite. Bastnaesite beforsite is a carbonate-rich mineralized rock type, containing ferroan dolomite (ankerite) as the major carbonate phase, instead of calcite, and is largely unaltered. Locally this rock contains minor quartz. Beforsite is tan or grey to pinkish tan and contains abundant grey or purple to pink and white single-crystal barite phenocrysts. The matrix consists mainly of fine dolomite rhombs set in very fine interstitial material consisting mainly of bastnaesite with calcite and barite. The mineralogical composition of an average beforsite is about 55% dolomite, 25% barite, 15% bastnaesite, and 5% calcite. Zones of barite-rich beforsite, associated with barite-poor zones have been logged in core holes and noted during pit mapping. Compared with the sövite, beforsite in pit samples has higher Ln and Ba, along with lower Sr and Pb. Phosphate content is variable but can be high in areas of irregular late veinlets of felty monazite. This is known as “bone” monazite and can be as much as 5% of the rock.

Dark brown limonitic alteration occurs in places in the beforsite, particularly along faults and in structural zones. In many instances, the limonite forms rhomb-shaped pseudomorphs indicating it formed by replacing the ferroan dolomite. In addition, secondary lanthanide minerals occur in portions of the beforsite such as sahamalite [(Mg,Fe²⁺)Ln₂(CO₃)₄], synchisite [synchysite, CaLn(CO₃)₂F] and ancylite [SrLn(CO₃)₂(OH)•H₂O] which was also identified using XRD. Large amounts of these secondary LN carbonates occurring within beforsite are associated with secondary calcite. Along the south wall of the pit, the beforsite contains crude, nearly vertical banding. On close examination, this is seen to consist of braided discontinuous veins of late bastnaesite/calcite. This texture probably formed by upward streaming of lanthanum and calcium-rich residual fluids remaining in the beforsite after dolomite crystallization.

Bastnaesite Dolosovite

Bastnaesite dolosovite occurs in a 100 to 200 ft wide zone between the beforsite and sövite. It contains both dolomite and calcite and is generally limonitic. Similar to the beforsite, dark brown limonite commonly forms pseudomorphs after dolomite rhombs. The dolosovite generally contains white to pink recrystallized barite phenocrysts. Some dolosovite samples contain coarse bastnaesite as in the sövite, but often samples have fine, late beforsite-style bastnaesite. A line drawn along the interface

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between the zone of coarse (greater than 150 µm) bastnaesite average crystal sizes and the zone characterized by fine (less than 150 µm) average crystal size roughly bisects the bastnaesite dolosovite zone.

Chemically, the dolosovite shows both sovitic and beforsitic attributes. It is highly variable in terms of gangue mineralogy, particularly with regard to the carbonate minerals which show much evidence of secondary redistribution. In some samples, dolomitization is obvious, along with later limonitic replacement of the dolomite. In other locations, late white to brown calcite veining is abundant.

Some consider the dolosovite to be a hybrid rock and not a separate intrusive type. In this case, it is plausible it was formed by carbonate redistribution during and after intrusion of the beforsite. Based on bastnaesite grain size, it is mainly dolomitized sövite; but contains some finely divided bastnaesite and is in part calcitized beforsite. Strongly limonitized dolosovite, referred to as “black ore”, creates extreme milling problems. “Black ore” is mainly restricted to the dolosovite but in places extends into the beforsite. This material is generally dark brown soft material with white calcite veining. It typically exhibits high lanthanum content, carrying large amounts of coarse or fine grained bastnaesite. In part, the elevated lanthanide (Ln) values may be due to removal of carbonate, resulting in an abundance of void space allowing the formation larger grain sizes. This material generally has relatively low densities and is poorly indurated. Analysis of this rock type shows that bastnaesite dolosovite has above average iron, manganese, and phosphorous contents as compared with the bastnaesite sövite.

The bastnaesite dolosovite has high strontianite contents where derived from sovitic rock. It is also locally high in fine, anhedral, late-stage silica. Although the dolosovite appears to be dominated by alteration minerals, it rarely contains talc.

Ln-bearing minerals other than bastnaesite commonly occur in the dolosovite, though mainly as minor phases. Bright yellow synchisite replacing bastnaesite was observed in many thin sections. Secondary sahamalite and ancylite have also been identified in many dolosovite samples. Bastnaesite in dolosovite is generally yellow-brown or dark-brown, rather than in normal light tan to grey colors. Bone monazite is more abundant than primary monazite.

White Sövite

White sövite occurs above the beforsite in the southwest corner of the pit (current pit bottom 4,300 ft). It carries very fine, late bastnaesite as in the beforsite, but contains little or no dolomite. White sövite appears to be the product of late stage calcitization of beforsite by rising residual fluids responsible for late bastnaesite/calcite deposition in the underlying beforsite.

In addition to fine bastnaesite, the white sövite contains abundant single-crystal barite phenocrysts as in the beforsite. Chemically, white sövite has high Ln and low Pb relative to beforsite. Its Sr content ranges from low to moderate. Phosphate contents are variable, with most present as veins of bone monazite.

On the 4640 level, the white sövite is exposed as a thick dike within hangingwall stockwork breccia 10 to 20 ft above the beforsite. Drillhole 85-1 intercepted 80 ft of white sövite before encountering dolomitic carbonatite.

Parisite Sövite

Parisite sövite is found in the pit above the 4700 level in the footwall. A dike carrying about 20% of flow-oriented parisite [CaLn₂(CO₃)₃F₂] was mapped on the 4760 level at the south end of the pit. This

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dike was intercepted in core hole 85-2. More information about this rock type is discussed by Sherer (1979).

Monazitic Carbonatite

Bodies of carbonatite which contain primary monazite in amounts that approach or exceed bastnaesite contents occur within, and adjacent to, the mineralized zone. In addition, monazitic sövite comprises most of the small carbonatite dikes in the vicinity of the mineralized zone.

The monazitic carbonatite has low total TREO content, generally in the 2% to 4% range. It is also characterized by high Ca and P, and low Ba. In hand specimen, the monazitic carbonatite is nearly equigranular because barite phenocrysts are sparse or lacking.

Although sovitic and beforsitic carbonate rock types have both been documented, nearly all of the monazitic-bearing carbonatite rocks observed on the 4700 to 4640 levels are dolosovite. Monazite sövite is abundant in core holes drilled on the north part of the pit. Significant amounts of monazite dolosovite occur at the south end of the mineralized zone and extend beneath the mill.

Monazitic carbonatite is generally associated with brecciated rocks. Small, phlogopitized clasts are commonly present in the monazite carbonatite as well as phlogopite xenocrysts. At the north and south ends of the pit monazitic carbonatite appears to form envelopes around breccia masses. A large monazite dolosovite mass along the hangingwall of the deposit contains areas rich in clasts.

The monazite in the monazitic carbonatite occurs predominantly as primary euhedra or subhedra. Bone monazite replaces primary crystals in some samples. Where present, bastnaesite occurs as sparse corroded grains, generally observed in coarser sizes similar to those documented in the basal sövite.

The location of monazitic carbonatite masses, and the lack of barite phenocrysts suggest the monazitic magma was filter pressed out of the adjacent breccias. Formation of the monazitic carbonatite units probably post-dated sövite emplacement and predated beforsite emplacement.

Alteration in the monazitic carbonatite is similar to that observed in the dolosovite. However, “black ore” formed from monazitic carbonatite has not been recognized to date.

Breccia

Breccia with a carbonatite matrix comprises a significant proportion of the Mountain Pass carbonatite body. Like the related monazitic carbonatite, the breccia nearly always has low lanthanum oxide (LnO) and high P and has historically not been added to mill feed in significant quantities. Breccia has been observed in abundance at the north end of the current pit, and essentially limits mining in that direction due to metallurgical concerns. Breccia is also present at the south end of the pit, where considerable tonnages extend under the current mill location.

As observed by Sherer (1979), breccia occurrences associated with the main carbonatite body at the Project are variable. The breccia bodies were previously noted to be semi-continuous envelopes on the hangingwall and footwall contact with the carbonatite intrusion and interlayered within the mineralized rock types. In the hangingwall, they range from stockworks of randomly oriented or sheeted carbonatite dikes cutting altered gneiss, clast-supported breccia with more than 70% altered angular clasts, to matrix-supported breccia with angular to rounded clasts which locally grades into monazitic carbonatite with sparse clasts.

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In the footwall, abundant rounded clasts of gneiss, shonkinite, and syenite occur in a crushed rock matrix with little or no carbonatite. This breccia grades to matrix supported breccia with rounded clasts. Some footwall breccia has protomylonitic textures, along with occurrences of talc and crocidolite. Breccia at the north end of the pit is strongly altered to talc, which renders clast identification difficult. Brecciated zones have also been observed internal to the main carbonatite body.

6.4 Surrounding Rock Types

The carbonatite stock at the Project is intruded into the metamorphic rocks and the ultrapotassic suite. Both of these rock types are typically strongly fenitized near their contacts with carbonatite, and fenitized clasts are commonly included in igneous breccias at the edges of the intrusion (Castor, 1988).

6.5 Relevant Geological Controls

The primary geologic control on mineralization is lithology; and only the carbonatitic rock types appear to be favorable for economically significant rare earth mineralization. Although a number of high-angle normal faults bisect the mineralized zone, offset appears to be post mineral in all cases.

6.6 Deposit Type, Character, and Distribution of Mineralization

Mountain Pass is a carbonatite hosted rare earth deposit (USGS Deposit Model 10; Singer, 1986). The mineralization is hosted principally in carbonatite igneous rock. Mountain Pass is the only known example of a rare earth deposit in which bastnaesite is mined as the primary magmatic economic mineral in the world (Haxel, 2004).

Mineralization occurs entirely within the carbonatitic portion of the currently drilled geologic sections, although grade distribution internal to this mineralized zone is variable. Higher grade zones (>10% TREO) tend to occur in lenses parallel to the hangingwall/footwall contacts, both downdip and along strike. Continuity of mineralization internal to the carbonatite zone is well defined both along strike and downdip.

The currently defined zone of rare earth mineralization exhibits a strike length of approximately 2,750 ft (850 m) in a north-northwest direction and extends for approximately 3,000 ft (930 m) downdip from surface. The true thickness of the >2.0% TREO zone ranges between 15 to 250 ft (5 to 75 m).

Globally, carbonatites are subdivided into two main groups: apatite-magnetite bearing, mined for iron and/or phosphorus ± various by-products, and rare-earth bearing carbonatites. Many other commodities may be present in economically significant concentrations, such as uranium, thorium, titanium, copper, vermiculite, zirconium, niobium, and phosphorus (Singer, 1986). The majority of carbonatite complexes display a series of variable carbonatitic magma compositions, the majority of which are not significantly enriched in rare earths. Mountain Pass is unique in that the carbonatite does not exhibit such variation and has significant intervals of elevated rare earths throughout its entirety.

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7 Exploration and Drilling

7.1 Exploration

In 1949, the rare earth-bearing carbonatite was discovered by a USGS field team (Olson, et al., 1954). The discovery and exploration details of Mountain Pass was published in USGS Professional Paper 261, which included regional and local scale geological and structural maps as well as maps of the underground workings at the Sulfide Queen Mine. USGS Professional Paper 261 details petrography, mineralogy and chemical analyses in addition to structural and geologic data collected by the USGS. This document served as the basis for further exploration and eventual exploitation of the Mountain Pass Mine.

There is no other relevant exploration work, other than drilling, conducted by or on behalf of current and previous owners at the Mountain Pass Mine. Drilling is discussed in Section 7.2.

7.2 Drilling

Extensive drilling at the Mountain Pass mine has been undertaken since the 1950’s, some of which is utilized to define the orebody and relevant geological features. The prior owner, Molycorp, completed drilling campaigns in 2009, 2010 and 2011. Data prior to those exploration campaigns is historic. While this provides good geological and grade information, the historic drilling has no quality control data associated with it. In 2021, MP Materials performed a limited geotechnical and exploratory drilling campaign, and handled core logging/sampling in a similar manner to the 2009-2011 drilling

The 2009 drilling campaign consisted of an in-fill drilling program to upgrade the resource classification within and adjacent to the existing Sulfide Queen area. The program consisted of twelve, 5.5-inch reverse circulation holes around the south, west, and north sides of the pit. The 12 holes ranged in depth from 230 to 1,245 ft (70.1 to 379.5 m) and were drilled between December 2009 and February 2010. Sampling was done on 5 ft (1.524 m) intervals, and the bagged samples were delivered by SRK to the on-site sample prep facility. Among the 12 holes, MP-09-01 is missing all data.

The 2010 program was designed as a diamond core in-fill, exploration, and condemnation program. The program consisted of two core in-fill holes on the south side of the pit, two core exploration holes north of the pit, and two condemnation holes. One condemnation hole was diamond core drilled northwest of the existing waste rock dump to test a possible future tailings site; the other was a reverse-circulation (RC) hole drilled northeast of the pit, at the site of the separation plant expansion. Core sampling was conducted on 5 ft intervals and bagged samples were stored at the on-site sample preparation facility. RC samples were submitted as approximate 10-kilogram (kg) splits of the original recovered sample

In 2011, Molycorp initiated a new infill drilling campaign; however, this data was not included in the current resource estimation as wireframing had finished before the results were available. This data was incorporated for the first time in this new resource estimate. In addition to routine total rare earth assaying, Molycorp randomly selected 683 core samples for laboratory analysis of the individual light rare earth components.

Core recoveries from the 2009 and 2010 drill campaigns exceeded 95%. MP Materials has noted similar results for the 2011 and 2021 drilling as well. Sample protocols described in Sections 8.1

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through 8.3 of this report provide reproducible results. SRK is of the opinion that drilling and sampling in these campaigns provides generally accurate and reliable results.

MP Materials conducted a geotechnical / exploration diamond core drilling campaign in 2021 with 16 holes drilled at a total depth of 10,136 ft for engineering as well as resource modeling purposes. All cores have been sampled at an interval of 10 ft on host rocks, and 5 ft on ore rocks.

Figure 7-1 illustrates the locations of the drillholes, color coded by drill campaign. Several drillholes are located outside of the field of view but these do not impact the mineral resource model which is shown as block grades on the pit surface.

Year 2021 2010 2000 1990 -8000c. 00 1980 1970

Note: colored points are drill collars shaded by relative approximate date of drilling.

Source: SRK, 2019

Figure 7-1: Drilling in MP Materials Pit Area

Geotechnical data for the project was acquired by detailed rock fabric mapping of surface exposures and subsurface sampling using drill core. SRK has reviewed the industry-accepted procedures and methods used by Call and Nicholas, Inc. (“CNI”), which are documented in Nicholas & Sims (2001) to characterize the rock mass. In SRK’s opinion, the geotechnical conditions are well characterized, and a sufficient number of holes have been drilled into the final pit wall to interpret the ground conditions.

CNI conducted laboratory testing to determine the intact and fracture strengths of the rock mass at their laboratory in Tucson, Arizona. Laboratory testing at this laboratory is done in general accordance with procedures outlined in ASTM standards for rock and soil testing. Using the intact and fracture strengths, rock mass strength estimates were developed using a procedure outlined in the Guidelines for Open Pit Slope Design (Read & Stacey, 2009). SRK has reviewed the rock mass strength calculations and inputs to the stability analysis. SRK concurs with the methods, approach, and results of the documented geotechnical study and interpretation of the results. Further discussion of the geotechnical parameters used for open pit mine design is presented in Section 13.1.

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8 Sample Preparation, Analysis and Security

In 2021, MP Materials performed a limited geotechnical and exploratory drilling campaign. The majority of data in the resource database is from historic drilling conducted prior to 2009. SRK has relied on prior discussions, from the time of Molycorp ownership, with former site geologists (e.g., Geoff Nason and John Landreth) for description of sample collection, preparation, analysis and security (Nason and Landreth; personal communication; 2009). SRK conducted a verification program at the Project between 2009 and 2010 that included reanalysis of archived core from historic drilling programs and a limited infill program. This is discussed in Section 9.2.

Subsequent to this, Molycorp completed an exploration/delineation drilling program during 2011. Additional wells for monitoring purposes were installed in 2012-2013. All sample processing was conducted at the Project. No additional drilling was completed until 2021, during which MP Materials drilled a series of 16 holes for geotechnical purposes (GT series), some of which were in carbonatite zones and featured economic mineralization. Similar to previous programs, samples were processed and analyzed at the on-site laboratory with duplicate samples analyzed by an outside lab for validation. SRK toured the laboratory and prep facility on site during an August 10-13, 2021, site visit. SRK is of the opinion that the sample preparation, security, and analytical procedures are adequate for reliance in the mineral resource estimation. Any uncertainty related to the historical or variable nature of the analyses have been dealt with in mineral resource classification as described in Section 11 of this report.

8.1 Historical Sampling

The sample and drilling procedures prior to 2009 described by Nason and Landreth (2009) indicate that during drilling, the core or drill cuttings were in the custody of the drillers or geologists or secured in an onsite storage location at all times. Field geologists delivered samples to the sample preparation area. The sample preparation and laboratory facilities were within the secured Mountain Pass property boundary. This was industry standard practice at the time for ongoing exploration at an operating mine. Access to the Mountain Pass Mine is controlled by security at the gate 24 hours per day. Drilling since 2009 has been conducted in and around the open pit, which is a restricted area. All drill cores and RC samples were transported from the drill sites by a Molycorp employee and stored in a secure storage area until the core or RC chips were logged. Sample security was controlled and supervised by Molycorp personnel. Molycorp observed industry best practice chain of custody.

Nason and Landreth (2009) described the sampling methods prior to 2009. After the core was logged, a geologist selected sample intervals for analysis. Sample intervals were based on lithology and were generally 5 ft in mineralized zones. It was the practice at the time of the historic drilling campaigns to only sample material that was visually mineralized. Sample intervals could be shorter or slightly longer at lithological contacts and through fault zones. Lithological contacts are generally sharp and recognizable.

The core was split longitudinally using a hydraulic core splitter. Half of the core was placed in a bag for analysis and the remaining half retained for geological reference. Following sample collection, the samples were delivered to the sample processing facility located in the mill facility. Preparation of the split core samples included overnight drying and subsequent crushing and pulverizing. The entire crushed and dried sample was then passed through a cone crusher, homogenized and split using a Jones splitter to a 100 gram (g) sample. Reject material was placed in envelopes and labeled for

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storage. From the 100 g sample, 10 g was delivered to the on-site lab for XRF analysis. The grain size of the 90 g of remaining sample was further reduced using a shatterbox swing mill. A split of the pulverized material was placed in sample envelopes and delivered to the Mountain Pass Lab. All pulp and coarse rejects were packaged and labeled. After analysis the pulp and coarse rejects were returned to the geology department for onsite storage.

SRK was not able to independently verify or observe the sampling methods employed during the historic drilling campaigns and has relied on verbal and written descriptions of the processes by former employees of Molycorp and its predecessors. SRK reviewed drill logs, sample summary sheets, a limited number of coarse and pulp rejects and remaining drill core. The remaining drill core is stored on site and is organized by drillhole and interval. Coarse and pulp rejects are no longer available on site.

SRK conducted a random inspection of the historic sample preparation area and core in the storage areas from the various major drilling programs and is of the opinion that sample handling, sample preparation and storage of core and rejects meets current industry accepted practices.

8.2 Sampling 2009-2011

The 2009 to 2011 drilling programs include photographs of core, a system of marking sample intervals on the core boxes, a sample numbering system and record-keeping for all sample intervals in the drill log.

Sampling procedures followed by SRK include:

• A written record of the sample collected

• Marking the sample interval on the core box

• Identifying the sample interval and box interval on the inside top of the box

• Photographing the core as both dry and wet core and core box top

• Placing the split core into a pre-labeled sample bag

• Inserting core blocks at the beginning and end of the removed core

• Inserting a lath cut to the sample interval as a space keeper in the core box

Sample numbers were generated using a combination of the drillhole identification and from-to sample interval. Control samples were placed in the sample stream with similar numbers using a drillhole and interval so as to be unrecognizable to the laboratory. The sample interval used for control samples was beyond the total depth of the drillhole to eliminate confusion with an actual sample. This was noted on the sample log to avoid future confusion on total depth of drillholes.

8.3 Sampling 2021

Procedures of sampling 2021 drilling cores are similar to the procedures used in 2009-2011. Core samples were collected by MP Materials’ geologists, logged, split and provided to the on-site prep lab for analysis.

8.4 Laboratory Analysis

There were various analytical procedures used by MP Material’s predecessors for sample preparation and analytical methods. Historically, Quality Assurance/Quality Control (QA/QC) samples were not inserted into the sample stream as part of the drilling programs.

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There were two types of analytical techniques used for measuring TREO at the Project:

• Gravimetric methods

• X-ray fluorescence (XRF)

Results for rare earths were typically reported as TREO.

The analysis for the drilling data in the existing assay database was obtained primarily by XRF analysis.

8.4.1 Note on Assay Terminology

For many rare earth projects currently in the public domain, laboratory results typically include assays for all the individual rare earth oxides as well as for Y₂O₃ which is not strictly speaking a rare earth oxide but is geochemically very similar and therefore is often geologically associated with heavy rare earth oxides. The exact grouping of individual oxides into light and heavy categories is not consistent from one project to another.

Mountain Pass, in common with most other carbonatite deposits, is considerably enriched in light rare earth oxides (“LREO”) compared with heavy rare earth oxides and Yttrium (“HREO+Y”), due in this case to the predominance of bastnaesite whose mineral structure favors inclusion of lighter rare earth elements. The Mountain Pass assay package was limited to the lighter rare earth oxides, specifically La₂O₃, CeO₂, Pr₆O₁₁, Nd₂O₃, and Sm₂O₃ and these were routinely summed together and reported as a single value representing the sum of the five individual oxide assays. Therefore, for the Mountain Pass project, the grades entered into the drillhole database as “LnO” or “REO” and presented in this report as “TREO” represent the sum of La₂O₃, CeO₂, Pr₆O₁₁, Nd₂O₃, and Sm₂O₃.

Many rare earth projects discuss LREO or HREO+Y ratios by expressing one group as a percentage of the sum (LREO+HREO+Y) and may refer to this summed assay value as TREO or TREO+Y; however, this is not the case for Mountain Pass.

Specifically, the definition of the term TREO in this report is different from the same term typically used when discussing other projects; in this report, TREO is the sum of La₂O₃, CeO₂, Pr₆O₁₁, Nd₂O₃, and Sm₂O₃ and it excludes the heavier rare earth oxides and yttrium oxide.

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8.4.2 Historical

Prior to 1970, Molycorp used a gravimetric method for samples from the drilling and sampling programs. The gravimetric method determined Re₂O₃% and was reported as TREO%. In this method, approximately 0.5 to 1.0 g of sample was dissolved through heating in a mixture of perchloric acid (HClO₄) and hydrogen peroxide (H₂O₂). The rare earths were then isolated in two precipitation and dissolution steps using organic solvents and inorganic rinses. The first step involved using phenolphthalein and NH₄OH and the second used oxalic acid. This procedure separated the TREO and thorium from iron, aluminum, uranium, titanium, phosphate, manganese, alkaline and alkali earth metals and other divalent cations. The final filtered precipitate of RE-oxalate was then ignited at 900 to 1,000°C and when cooled weighed as total Re₂O₃ (Jennings, 1966). SRK does not know the detection limit for this technique.

8.4.3 Current

The equipment used for the historic drilling programs was replaced with newer models and the on-site laboratory no longer primarily relies on the wet chemistry method that was standard during the early drilling programs.

Molycorp equipped the on-site lab with state-of-the-art equipment for analysis of rare earths. Currently, the on-site lab uses XRF and Inductively Coupled Plasma (ICP) techniques for determination of individual rare earth species and reports the analysis as individual TREO and TREO. Laboratory equipment at the on-site laboratory includes:

• One Philips PW2404 x-ray spectrometer XRF with a PW2450 VRC sample changer capable of running up to 150 samples per day (the lab is currently capable of prepping 50 fusion disks per day)

• One X’Pert PRO X-ray Diffraction (XRD) PANalytical

• One Perkin and Elmer Atomic Absorption Spectrometer (AAS)

• Two Ultima2 Inductively Coupled Plasma Atomic Emission spectrometers (ICP-AES) each capable of 100 samples per day

• One Agilant Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) with an Agilant 7500cc Octopole Reaction System capable of speciation that can analyze 600 samples per day

Table 8-1 presents the detection limits for the oxides and TREO parameters.

Table 8-1: Oxides and TREO Detection Limits, Mountain Pass Laboratory

Oxide	P2O5	ThO2	SiO2	Fe2O3	MgO	CaO	SrO	BaO
Limit (%)	0.05	0.01	0.05	0.05	0.05	0.05	0.05	0.05
TREO	TREO	CeO2	La2O3	Pr6O11	Nd2O3	Sm2O3
Limit (%)	0.1	0.03	0.03	0.02	0.02	0.02

Source: SRK, 2012

8.4.4 2009 and 2010 Samples

Analyses of check assays and infill drilling samples were completed between 2009 and 2010 and were conducted at both the Mountain Pass Laboratory and at SGS Minerals in Lakefield, Ontario Canada. SGS Minerals has ISO/IEC 17025 accreditation.

Details of sample preparation and analysis for SGS Minerals are discussed in Section 9.

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Samples included:

• Field blanks (roadside marble and scoria grab samples)

• Pulp blanks prepared from purchased silica sand

• Field duplicates (i.e., two splits of RC cuttings collected at the drill rig)

• Coarse reject duplicates

• Pulp duplicates

• A pit standard (pulp prepared by Mountain Pass)

8.4.5 2011 Samples

The analysis for the 2011 drilling program completed by Molycorp was conducted at Actlabs in Ancastor, Ontario, Canada using the Code 8 Rare Earth Element Assay Package. In this package, the analysis is conducted using a lithium metaborate/tetraborate fusion followed by dissolution in acid and analysis by ICP-MS. Detection limits for this technique are shown in Table 8-2. Actlabs has ISO/IEC 17025 accreditation.

Table 8-2: Oxides and Element Detection Limits, Actlabs Laboratory

Oxide or Element	Detection   Limit	Element	Detection   Limit	Element	Detection   Limit	Element	Detection   Limit
Al2O3	0.01%	Be	1 ppm	Rb	2 ppm	La	0.1 ppm
CaO	0.01%	Bi	0.4 ppm	Sb	0.5 ppm	Ce	0.1 ppm
Fe2O3	0.01%	Co	1 ppm	Sc	1 ppm	Pr	0.05 ppm
K2O	0.01%	Cr	20 ppm	Sn	1 ppm	Nd	0.1 ppm
MgO	0.01%	Cs	0.5 ppm	Sr	2 ppm	Sm	0.1 ppm
MnO	0.001%	Cu	10 ppm	Ta	0.1 ppm	Eu	0.05 ppm
Na2O	0.01%	Ga	1 ppm	Th	0.1 ppm	Gd	0.1 ppm
P2O5	0.01%	Ge	1 ppm	Tl	0.1 ppm	Tb	0.1 ppm
SiO2	0.01%	Hf	0.2 ppm	U	0.1 ppm	Cy	0.1 ppm
TiO2	0.001%	In	0.2 ppm	V	5 ppm	Ho	0.1 ppm
LOI	0.01%	Mo	2 ppm	W	1 ppm	Er	0.1 ppm
Ag	0.5 ppm	Nb	1 ppm	Y	2 ppm	Tm	0.05 ppm
As	5 ppm	Ni	20 ppm	Zn	30 ppm	Yb	0.1 ppm
Ba	3 ppm	Pb	5 ppm	Zr	4 ppm	Lu	0.04 ppm

Source: Modified from Actlabs fee schedule (http://www.actlabs.com/files/Canada_2012.pdf, 2012

8.4.6 2021 Samples

A relatively small subset of the database is comprised of samples taken during 2021 geotechnical drilling. These samples function for two purposes, primarily as additional information to characterize select interceptions of mineralization, and secondly as verification of the sample prep and analysis methodology employed by the Mountain Pass laboratory.

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9 Data Verification

9.1 Quality Assurance/Quality Control Procedures

9.1.1 Historical

During the drilling programs at the Project, which were conducted prior to 1992, there was no QA/QC in place that included the regular insertion of standards, blanks and duplicates into the sample stream. SRK located a limited number of laboratory printouts but no analytical certificates. Within the printouts, SRK found a limited number of re-analyses, but these were not systematic, appeared to be confirmation of higher grades and did not represent the entire spectrum of analytical results. Current laboratory personnel report that instrument QA/QC was in place at the on-site laboratory during these drilling programs, but no records are available.

The pre-1992 drilling comprises more than half of the drilling used in the resource model. The uncertainty that results from the lack of QA/QC is counteracted by the production reconciliation presented in this report.

9.1.2 2009-2010 Program

The infill drilling program conducted in 2009 through 2010 used both the Mountain Pass laboratory and SGS Lakefield for sample assaying. Figure 9-1 illustrates the assay results returned for the pit standard. The pit standard was prepared and homogenized by Molycorp and was not subjected to a round robin assay study which would normally be completed to ‘certify’ the standard material; nevertheless, the results were quite precise and both laboratories were broadly in agreement with each other with Mountain Pass laboratory returning slightly lower grades on average than SGS laboratory.

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Pit Standard Submissions 2009-2010 R-4 R-4 R-4 MP-10-02 MP10-01 -Mountain Pass Laboratory --SGS Laboratory MP10-01 MP10-01 MP-10-05 MP-10-05 MP-10-05 MP-10-04 MP-10-04 MP-10-04 MP-10-04 MP-09-06 MP-09-06 MP-09-06 MP-09-06 MP-09-02 MP-09-02 MP-09-02 9

Source: SRK, 2019

Figure 9-1: 2009 Through 2010 Pit Standard Assays

A number of duplicate samples were submitted during the course of the program to assess the repeatability of sample assays both for field duplicates and for pulp duplicates. Figure 9-2 illustrates the results, generally both field and pulp duplicates compare closely, the half average relative difference for each dataset is up to +/-17% and up to +/-6% respectively. This shows that the mineralization is reasonably homogeneous within the drill core and that there is only limited potential for sampling error.

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20.00 Mountain Pass 2009-2010 Duplicates Field Duplicates Pulp Duplicates 0.00 16.00 18.00 14.00 20.00 12.00 Original Submission Grade (%TREO) 8.00 6.00 10.00 18:00 16.00 14.00 10000 8.00 6.00 4.00 2.00 Duplicate Submission Grade (%TREO) 2:00 4.00 12.00

Source: SRK, 2019

Figure 9-2: 2009 Through 2010 Duplicates

9.1.3 2011 Program

The 2011 drilling program included the insertion of blanks and duplicates but no standards. The prior standard samples were depleted during the 2010 drilling campaign. Blanks, standards, and duplicates are part of an industry best practice drilling program and are used to independently check precision and accuracy during analysis.

SRK was not provided with the QA/QC data from the 2011 drilling program. As a result, SRK has not reviewed this QA/QC data and cannot comment.

9.1.4 2021 Program

The 2021 drilling included a series of field duplicate analyses and four blank insertions into the sample stream. No standards (certified reference materials) were inserted to test laboratory precision. Duplicates were collected as quarter core from the remaining half not sent for analysis as the primary sample. One quarter was provided to the Mountain Pass lab to test against the primary half core sample. The second quarter was sent to ALS Minerals in Tucson, AZ for processing and ALS Minerals Vancouver for analysis. While the comparison for the duplicates within the MP lab (Figure 9-3) show excellent agreement, the comparison for the duplicates submitted to ALS (Figure 9-4) appear relatively poor, with significant deviations in grade from the original Mountain Pass sample. In SRK’s opinion, this likely demonstrates differences between laboratories in terms of preparation/analytical methodology.

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18.00 0.00 0.00 2.00 4.00 6.00 5.00 10.00 Original 15.00 20.00 ... Linear (Duplicate TREO) 10.00 Duplicate 8.00 12.00 16.00 14.00 Duplicate TREO

Source: SRK, 2021

Figure 9-3: 2021 Field Duplicate Analyses – MP Materials Lab

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16.00 14.00 12.00 10.00 8.00 6.00 4.00 2.00 0.00 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 -2.00 MP REO ALS Linger (REO ALS)

Source: SRK, 2021

Figure 9-4: External Duplicate Analyses – MP vs. ALS

9.2 2009 Re-Assaying Program

Based on the review of historic sample preparation and analytical procedures, SRK initiated a check assay program. The material remaining from historical drilling programs consisted of archived split core stored on site in locked SeaVans. Most of the coarse and pulp rejects had been discarded. Because of this, the sample check program was conducted using split core.

For this check assay program, samples were prepared at SGS Minerals preparation laboratory located in Elko, Nevada, USA. (SGS Elko). The primary analytical laboratory used for this program was SGS Minerals (SGS Minerals) located in Lakefield, Ontario, Canada and approximately 10% of these check samples were also analyzed on site at the Mountain Pass Laboratory.

9.2.1 Procedures

The 2009 sample check program included re-analysis of approximately 1% of the historic assay database results. The program included the following sample types and numbers:

• 108 core samples with original assay results between 0.18% to 16.30% TREO

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• 10 site-specific standard samples based on two samples of known TREO content

• 10 blind duplicates

• 5 blank samples

SRK selected random duplicate samples from sample intervals within the database that covered a range of analytical results from 0.18% TREO to 16.30% TREO. Since these duplicate samples are second half of the archived split core, they are effectively field duplicates. Of the 108 core samples, 66 core samples had historic assay results between 3.00% and 11.00% TREO. The remaining 42 core samples had historic assay results between 0.18% and 2.99% or 11.01% and 16.30% TREO.

Standards and blanks were site specific. The site-specific standards are non-certified and were created by the on-site laboratory from a pit sample and a high-grade sample from the Birthday claim. The blank material was a non-mineralized sample collected at the Mountain Pass site by SRK.

SRK directed SGS Elko to prepare ten duplicates from the pulverized samples and to give them unique sample numbers. The duplicates were prepared and inserted into the sample stream prior to shipping to the SGS Minerals laboratory for analysis. Ten pulverized splits of the core samples were also sent back to the on-site laboratory for comparative analysis. The pulverized splits are considered pulp duplicates, which are allowed a ±10% error.

In addition to the SRK QA/QC samples, SGS Minerals included one blank, one sequential duplicate (i.e., a duplicate placed immediately after the primary sample) and three additional duplicates per batch at the analytical lab in Lakefield. The analysis was run in two batches, so this totaled two blanks, two in-line duplicates and six duplicates in addition to those inserted under the direction of SRK. Calibration standards were provided by the Mountain Pass Laboratory to insure similar analytical sensitivity for both labs.

Technicians at the Mountain Pass Laboratory inserted two duplicates and one standard in the ten samples analyzed onsite.

Ten samples were selected from the core samples and sent to ALS Chemex in Reno, Nevada U.S.A for specific gravity measurements. Specific gravity is discussed further in Section 11.5.

9.2.2 SGS Check Assay Sample Preparation

Sample preparation for the check analysis was completed at SGS Elko. The preparation technique used was SGS Minerals code PRP90, which used the following procedures:

• The sample was dried at 100°C for 24 hours.

• The sample was crushed to 90% passing a 2-millimeter (mm) (10 mesh) screen.

• The sample was split using a riffle splitter to 250 g.

• The 250 g split was placed in a vibratory mill and pulverized until 85% passed a 75-micron (200 Mesh) screen.

• The coarse reject was retained and returned to the client for any future analysis.

The sample was then shipped to the SGS Minerals laboratory for XRF analysis (SGS Minerals, 2009).

9.2.3 SGS Check Assay XRF Procedures

SGS Minerals worked closely with the Mountain Pass Laboratory to identify the appropriate method for preparing fusion discs for the XRF to ensure that both labs used similar procedures for TREO

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analysis. A 0.2 g to 0.5 g pulp sample is fused with 7 g of a 50/50 mixture of lithium tetraborate and lithium metaborate into a homogenous glass disk. This is then analyzed using a wave dispersive XRF (WDXRF). Loss on ignition at 1000°C is determined separately using gravimetric techniques and is part of the matrix correction calculation. These calculations are performed by WDXRF software (SGS, 2009). This method is accredited with the Standards Council of Canada (SCC) and conforms with the requirements of ISO/IEC 17025 (SGS, 2009).

The analyses performed for the SRK study were SGS Minerals control quality, which are used to monitor and control metallurgical or manufacturing processes. They are analyzed individually for better quality output. The oxides analyzed and their detection limits are listed in Table 9-1. The analytical work included Loss on Ignition (LOI) as a separate analysis.

Table 9-1: Oxides Analyzed with Detection Limits

Oxide	Limit (%)		Oxide	Limit (%)		Oxide		Limit (%)
Whole Rock Analysis
SiO2		0.01	Na2O		0.01		CaO		0.01
Al2O3		0.01	TiO2		0.01		MgO		0.01
Fe2O3		0.01	Cr2O3		0.01		K2O		0.01
P2O5		0.01	V2O5		0.01		MnO		0.01
Rare Earth Oxide Analysis
La2O3		0.01	CeO2		0.02		Nd2O3		0.02
Pr6O11		0.02	Sm2O3		0.03		BaO		0.02
SrO		0.02	ThO2		0.01

Source: SRK, 2012

9.2.4 Mountain Pass Laboratory Check Assay XRF Procedures

The Mountain Pass Laboratory check assay XRF procedures are discussed in Section 8.3.3.

9.2.5 Analysis of Light Rare Earth Oxide Distribution

Starting in 2009, Molycorp expanded the assay method to include the individual rare earths present in each sample. During the 2009 in-fill and 2010 condemnation drilling campaigns, SRK selected 403 samples for the assay of light rare earth elements (i.e., lanthanum, cerium, praseodymium, neodymium and samarium). Table 9-2 presents a statistical summary of the light rare earth element results.

Table 9-2: Light Rare Earth Oxide Distribution Statistics: 2009 and 2010 Analyses

Statistic	La2O3		CeO2		Pr6O11		Nd2O3		Sm2O3
Number of Samples		403		403		403		403		403
Mean Fraction of TREO		0.325		0.497		0.043		0.121		0.009
Standard Deviation		0.026		0.021		0.003		0.012		0.002