Exhibit 99.1

 

San Dimas Silver/Gold Mine

Durango and Sinaloa States, Mexico

NI 43-101 Technical Report on

Mineral Resource and Mineral Reserve Estimates

 

 

Qualified Persons:		Gonzalo Mercado, P.Geo. David Rowe, CPG Michael Jarred Deal, RM SME Andrew Pocock, P.Eng. María Elena Vázquez Jaimes, P.Geo.

 

Report Prepared For:		First Majestic Silver Corp.

 

Effective Date:		August 31, 2025
Report Date:		September 24, 2025

 

San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

Table of Contents

 

1.   SUMMARY			1
1.1.  Introduction			1
1.2.  Property Description, Location and Access			1
1.3.  History			3
1.4.  Geological Setting, Mineralization and Deposit Types			3
1.5.  Exploration			5
1.6.  Drilling			5
1.7.  Sampling, Analysis and Data Verification			6
1.8.  Mineral Processing and Metallurgical Testing			7
1.9.  Mineral Resource and Mineral Reserve Estimates			7
1.9.1.   Mineral Resource Estimates			7
1.9.2.   Mineral Reserve Estimates			11
1.10.  Mining Operations			14
1.11.  Recovery Methods			16
1.12.  Infrastructure, Permitting and Compliance Activities			16
1.13.  Capital and Operating Costs			18
1.14.  Conclusions			20
1.15.  Recommendations			20
2.   INTRODUCTION			21
2.1.  Technical Report Issuer			21
2.2.  Terms of Reference			21
2.3.  Cut-off and Effective Dates			21
2.4.  Qualified Persons			21
2.5.  Site Visits			22
2.6.  Sources of Information			23
2.7.  Previously Filed Technical Reports			23
2.8.  Units, Currency, and Abbreviations			23
3.   RELIANCE ON OTHER EXPERTS			25
4.   PROPERTY DESCRIPTION AND LOCATION			26
4.1.  Property Location			26
4.2.  Ownership			26
4.3.  Mineral Tenure			26
4.4.  Royalties			35
4.5.  Surface Rights			35
4.6.  Permitting Considerations			36
4.7.  Environmental Considerations			36
4.8.  Existing Environmental Liabilities			36
4.9.  Significant Factors and Risks			36
5.   ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE, AND PHYSIOGRAPHY			37
5.1.  Accessibility			37
5.2.  Climate			38

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

5.3.  Local Resources and Infrastructure			39
5.4.  Physiography			40
5.5.  Comment on Section 5			40
6.   HISTORY			42
6.1.  Ownership History			42
6.2.  Exploration History			44
6.3.  Production History			47
7.   GEOLOGICAL SETTING AND MINERALIZATION			48
7.1.  Regional Geology			48
7.1.1.   Stratigraphy			50
7.1.2.   Lower Volcanic Complex (LVC)			51
7.1.3.   Upper Volcanic Group (UVG)			52
7.1.4.   Intrusive Rocks			52
7.1.5.   Structural Geology			52
7.2.  Mineralization			54
7.3.  Deposit Descriptions			57
7.3.1.   West Block			60
7.3.2.   Graben Block			62
7.3.3.   Central Block			63
7.3.4.   Tayoltita Block			63
7.3.5.   Santa Rita Area			64
7.3.6.   El Cristo Area			65
7.3.7.   Alto De Arana Area			67
7.3.8.   San Vicente Area			68
7.3.9.   Ventanas Prospect			69
7.4.  Comments on Section 7			69
8.   MINERAL DEPOSIT TYPES			70
8.1.  Geological Setting			70
8.2.  Mineralization			70
8.3.  Alteration			71
8.4.  Applicability of the Low-Sulphidation Epithermal Model to San Dimas			71
8.5.  Comments on Section 8			73
9.   EXPLORATION			74
9.1.  Introduction			74
9.2.  Grids and Surveys			75
9.3.  Geological Mapping			75
9.3.1.   Surface Geological Mapping			75
9.3.2.   Underground Geological Mapping			77
9.4.  Geochemical Sampling			78
9.5.  Geophysics			81
9.6.  Remote Sensing			82
9.7.  Tunnelling			83
9.8.  Petrology, Mineralogy, and Research studies			85
9.9.  Exploration Potential			85

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

10.  DRILLING			86
10.1.  Drill Methods			86
10.2.  Core Handling and Storage			88
10.3.  Data Collection			88
10.4.  Drill Hole Logging Procedure			89
10.5.  Core Recovery			89
10.6.  Collar Survey			89
10.7.  Downhole Survey			89
10.8.  Geotechnical Drilling			89
10.9.  Specific Gravity and Bulk Density			90
10.10. Drill Core Interval Length/True Thickness			90
10.11. Comments on Section 10			91
11.  SAMPLE PREPARATION, ANALYSES AND SECURITY			92
11.1.  Sampling Methods			92
11.1.1.  Core Sampling			92
11.1.2.  Underground Production Channel Sampling			92
11.2.  Analytical Laboratories			93
11.3.  Sample Preparation and Analysis			93
11.3.1.  San Dimas Laboratory			93
11.3.2.  SGS Durango			94
11.3.3.  Central Laboratory			94
11.3.4.  ALS			94
11.4.  Quality Assurance and Quality Control (QAQC)			95
11.4.1.  Materials and Insertion Rates			95
11.4.2.  Transcription and Sample Handling Errors			96
11.4.3.  Accuracy Assessment			96
11.4.4.  Contamination Assessment			98
11.4.5.  Precision Assessment			100
11.4.6.  Between-Laboratory Bias Assessment			101
11.5.  Databases			103
11.6.  Sample Security			103
11.6.1.  Channel Samples			103
11.6.2.  Drill Core Samples			103
11.7.  Author’s Opinion and Other Comments on section 11			103
12.  DATA VERIFICATION			105
12.1.  Data Entry Error Checks			105
12.2.  Visual Data Inspection			105
12.3.  Review QA/QC Assay Results			106
12.4.  Site Visits			106
12.5.  QP’s Opinion and Other Comments on Section 12			106
13.  MINERAL PROCESSING AND METALLURGICAL TESTING			107
13.1.  Overview			107
13.2.  Metallurgical Testing			107
13.2.1.  Mineralogy			107

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

13.2.2.  Monthly Composite Samples			108
13.2.3.  Sample Preparation			108
13.3.  Comminution Evaluations			108
13.4.  Cyanidation, Reagent and Grind Size Evaluations			110
13.5.  Optimizing Process Studies			111
13.6.  Recovery Estimates			113
13.7.  Metallurgical Variability			114
13.8.  Deleterious Elements			119
14.  MINERAL RESOURCE ESTIMATES			120
14.1.  Introduction			120
14.2.  Mineral Resource Estimation Process			120
14.2.1.  Sample Database			121
14.2.2.  Geological Interpretation and Modeling			123
14.2.3.  Exploratory Sample Data Analysis			124
14.2.4.  Boundary Analysis			125
14.2.5.  Compositing			125
14.2.6.  Evaluation of Composite Sample Outlier Values			126
14.2.7.  Composite Sample Statistics			128
14.2.8.  Metal Trend and Spatial Analysis: Variography			129
14.2.9.  Bulk Density			130
14.2.10.  Block Model Setup			130
14.2.11.  Resource Estimation Procedure			131
14.2.12.  Block Model Validation			132
14.2.13.  Reconciliation			136
14.2.14.  Mineral Resource Classification			137
14.2.15.  Reasonable Prospects for Eventual Economic Extraction			139
14.2.16.  Mining Depletion			140
14.3.  Statement of Mineral Resource Estimates			140
14.4.  Factors that May Affect the Mineral Resource Estimate			142
14.5.  Comments on Section 14			142
15.  MINERAL RESERVES ESTIMATES			143
15.1.  Methodology			143
15.2.  Net Smelter Return			144
15.3.  Block Model Preparation			147
15.4.  Dilution			148
15.5.  Mining Loss			150
15.6.  Mineral Reserve Estimates			153
15.7.  Statement of Mineral Reserve Estimates			153
15.8.  Factors that May Affect the Mineral Reserve Estimates			155
15.9.  Comments on Section 15			155
16.  MINING METHODS			156
16.1.  General Description			156
16.2.  Mining Methods and Mine Design			157
16.2.1.  Geotechnical Considerations			157

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

16.2.2.  Hydrogeological Considerations			158
16.2.3.  Development and Access			158
16.2.4.  Mining Methods and Stope Design			160
16.2.5.  Ore and Waste Haulage			165
16.3.  Mine Infrastructure			166
16.3.1.  Mine Access and Underground Facilities			166
16.3.2.  Ventilation			166
16.3.3.  Backfill			169
16.3.4.  Dewatering			169
16.3.5.  Mine Water Supply			170
16.3.6.  Power Supply			170
16.3.7.  Compressed Air			171
16.3.8.  Explosives			171
16.4.  Development Schedule			171
16.5.  Production Schedule			171
16.6.  Equipment and Manpower			172
17.  RECOVERY METHODS			175
17.1.  Introduction			175
17.2.  Process Flowsheet			175
17.3.  Processing Plant Configuration			177
17.3.1.  Plant Feed			177
17.3.2.  Crushing			177
17.3.3.  Grinding			177
17.3.4.  Cyanide Leaching Circuit			178
17.3.5.  Counter Current Decantation (CCD) System			179
17.3.6.  Merrill Crowe Zinc Precipitation and Smelting			179
17.3.7.  Tailings Filtration and Management			180
17.3.8.  Sampling			180
18.  PROJECT INFRASTRUCTURE			182
18.1.  Local Infrastructure			182
18.2.  Transportation and Logistics			183
18.3.  Waste Rock Storage Facilities			183
18.4.  Tailings Storage Facilities			185
18.5.  Camps and Accommodation			187
18.6.  Power and Electrical			187
18.7.  Communications			189
18.8.  Water Supply			189
19.  MARKET CONSIDERATION AND CONTRACTS			190
19.1.  Market Considerations			190
19.2.  Commodity Price Guidance			190
19.3.  Product and Sales Contracts			190
19.4.  Streaming Agreement			191
19.5.  Deleterious Elements			191
19.6.  Supply and Services Contracts			191

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

19.7.  Comments on Section 19		192
20.  ENVIRONMENTAL STUDIES, PERMITTING, AND SOCIAL OR COMMUNITY IMPACT		193
20.1.  Environmental Aspects, Studies and Permits		193
20.2.  General		193
20.3.  Environmental Compliance in Mexico		193
20.4.  Existing Environmental Conditions		194
20.5.  Environmental Studies, Permits and Issues		194
20.5.1.  Surface Hydrology		194
20.5.2.  Surface Water Geochemistry		195
20.5.3.  Hydrogeology		195
20.5.4.  Soil		195
20.5.5.  Air Quality		195
20.5.6.  Noise		196
20.5.7.  Flora and Fauna		196
20.5.8.  Social and Cultural Baseline Studies		196
20.5.9.  Historical and Cultural Aspects		198
20.6.  Tailings Handling and Disposal		198
20.7.  Waste Material Handling and Disposal		199
20.8.  Mine Effluent Management		199
20.9.  Process Water Management		199
20.10. Hazardous Waste Management		200
20.11. Monitoring		200
20.12. Environmental Obligations		200
20.13. Permits		201
20.14. Closure Plan		204
20.15. Corporate Social Responsibility		205
20.15.1.  Ejidos		205
21.  CAPITAL AND OPERATING COST		207
21.1.  Capital Costs		207
21.2.  Operating Costs		207
22.  ECONOMIC ANALYSIS		209
23.  ADJACENT PROPERTIES		209
24.  OTHER RELEVANT DATA AND INFORMATION		209
25.  INTERPRETATION AND CONCLUSIONS		210
25.1.  Mineral Tenure, Surface Rights and Agreements		210
25.2.  Geology and Mineralization		210
25.3.  Exploration and Drilling		210
25.4.  Data Analysis		210
25.5.  Metallurgical Testwork		211
25.6.  Mineral Resource Estimates		211
25.7.  Mineral Reserve Estimates		211
25.8.  Mine Plan		212
25.9.  Processing		212
25.10. Markets and Contracts		213

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

25.11. Permitting, Environmental and Social Considerations			213
25.12. Capital and Operating Cost Estimates			213
25.13. Economic Analysis Supporting Mineral Reserve Declaration			213
25.14. Conclusions			214
26.  RECOMMENDATIONS			215
26.1.1.  Exploration			215
26.1.2.  Plant Leaching - Oxygen Addition			215
26.1.3.  Costs			216
26.1.4.  Mine Plan Compliance			216
27.  REFERENCES			217
28.  CERTIFICATES OF QUALIFIED PERSON			220

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

Index of Tables

 

Table 1-1: San Dimas Measured and Indicated Mineral Resource Estimate (effective date December 31, 2024)			10
Table 1-2: San Dimas Inferred Mineral Resource Estimate (effective date December 31, 2024)			10
Table 1-3: Economic Parameters assumed for calculation of NSR			11
Table 1-4: San Dimas Mineral Reserves Statement (Effective Date December 31, 2024)			13
Table 1-5 San Dimas Life of Mine Development Schedule			15
Table 1-6 San Dimas Life of Mine Production Schedule			16
Table 1-7: San Dimas Mining Sustaining Capital Costs Summary ($Million)			19
Table 1-8: San Dimas Operating Costs			19
Table 1-9: San Dimas Annual Operating Costs ($Million)			20
Table 2-1: List of Abbreviations and Units			24
Table 4-1: Summary of the Six Concession Groups, San Dimas Property			32
Table 4-2: San Dimas Concessions Group List			32
Table 4-3: Candelero Concessions Group List			34
Table 4-4: Ventanas Concession Group List			34
Table 4-5: Lechuguillas Concessions Group List			35
Table 4-6: Cebollas Concessions Group List			35
Table 4-7: Truchas Concessions Group List			35
Table 6-1: Summary History of San Dimas Property			44
Table 7-1: List of Major Veins by Mine Zone in the San Dimas Property District			58
Table 11-1: Analytical Laboratories			93
Table 11-2: Analytical Methods			95
Table 11-3: Summary of Inter-Laboratory Bias Check Results			101
Table 13-1: Grindability Test Results for Different Composite Samples (2025)			109
Table 13-2: Metallurgical Recoveries achieved in San Dimas 2021-2024			113
Table 14-1: Diamond Drill Hole and Production Channel Data by Mine Zone, San Dimas			121
Table 14-2: San Dimas - West Block Domain Names and Mine Codes			124
Table 14-3: West Block Composite Sample Lengths by Domain			126
Table 14-4: San Dimas Example - West Block, Composite Sample Capping by Domain			128
Table 14-5: San Dimas Example - West Block, Remaining Metal content by Domain after Capping			128
Table 14-6: Summary of Ag-Au Estimation Parameters for the Perez Block Model			132
Table 14-7: Input Parameters for Evaluation of Reasonable Prospects of Eventual Economic Extraction.			139
Table 14-8: San Dimas Measured and Indicated Mineral Resource Estimate (effective date December 31, 2024)			141
Table 14-9: San Dimas Inferred Mineral Resource Estimate (effective date December 31, 2024)			141
Table 15-1: Economic Parameters Assumed for Calculation of NSR			145
Table 15-2: Initial NSR Cut-Off Value Applied to Longhole			146
Table 15-3: Initial NSR Cut-Off Value Applied to Cut-and-Fill			147
Table 15-4: Dilution and Mining Loss Parameters			153

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

Table 15-5: San Dimas Proven and Probable Mineral Reserve Estimates (effective date December 31, 2024)			154
Table 16-1: San Dimas Geotechnical Units			157
Table 16-2: Development Profiles			159
Table 16-3: San Dimas Development 2018 to 2024			160
Table 16-4: Fresh Air Requirement			169
Table 16-5: San Dimas Life of Mine Development Schedule			171
Table 16-6: San Dimas Life of Mine Production Schedule			172
Table 16-7: Breakdown of Personnel as of May 2025			174
Table 16-8: Equipment Summary as of December 2020			174
Table 19-1: Metal Prices Used for the December 31, 2024, Mineral Resource and Mineral Reserve Estimates			190
Table 20-1: Summary of Surface Hydrology Studies			195
Table 20-2: Summary of Surface Water Studies			195
Table 20-3: Summary of Soil Sampling Studies			195
Table 20-4: Air Quality Studies			196
Table 20-5: Noise Impact Studies			196
Table 20-6: Flora and Fauna Studies			196
Table 20-7: Summary of Social Studies			198
Table 20-8: Tailings and Waste Rock Studies			199
Table 20-9: Environmental Monitoring Activities			200
Table 20-10: Major Permits Issued			203
Table 20-11: Permits in Process			204
Table 21-1: San Dimas Mining Sustaining Capital Costs Summary			207
Table 21-2: San Dimas Operating Costs Used in the LOM Plan			208
Table 21-3: San Dimas Annual Operating Costs			208

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

Index of Figures

 

Figure 4-1: Location Map, San Dimas Property			26
Figure 4-2: Map of the Concession Outlines for the San Dimas Property			27
Figure 4-3: Map of the San Dimas Concessions Group			28
Figure 4-4: Map of the Candelero Concessions Group			29
Figure 4-5: Map of the Ventanas Concessions Group			30
Figure 4-6: Map of the Lechuguillas Concessions Group			30
Figure 4-7: Map of the Cebollas Concessions Group			31
Figure 4-8: Map of the Truchas Concessions Group			31
Figure 5-1: Road Access to the San Dimas Property, near Tayoltita			38
Figure 5-2: Processing Plant, Airstrip and Rugged Terrain, Aerial View looking East			40
Figure 6-1: Map showing Mining Tunnels at the Time Wheaton River Acquired the Property			46
Figure 6-2: San Dimas Production from 2014 to 2024			47
Figure 7-1: Physiographic Provinces around the San Dimas District			48
Figure 7-2: Regional Geological Map of Central Sierra Madre Occidental			49
Figure 7-3: Stratigraphic Column, San Dimas District			50
Figure 7-4: Geological Map of San Dimas Property			51
Figure 7-5: San Dimas Structural Map			53
Figure 7-6: Regional Geological Section Across the San Dimas Property			54
Figure 7-7: The Jessica Vein Within the Favourable Zone, Vertical Section			55
Figure 7-8: Paragenetic Vein Sequence, San Dimas			56
Figure 7-9: Roberta Vein, Central Block, San Dimas			57
Figure 7-10: San Dimas Vein Distribution by Mine Zone			59
Figure 7-11: Vein Map, San Dimas			60
Figure 7-12: Longitudinal section, Guadalupe and Perez Veins, West Block, San Dimas			61
Figure 7-13: Longitudinal Section, Elia Veins, Graben Block, San Dimas			62
Figure 7-14: Longitudinal Section, Robertita Vein, Central Block, San Dimas			63
Figure 7-15: Longitudinal Section, San Luis Vein, Tayoltita Block, San Dimas			64
Figure 7-16: Longitudinal Section, Magdalena Vein, Santa Rita Area, San Dimas			65
Figure 7-17: Longitudinal Section, Camichin Vein, El Cristo Area, San Dimas			66
Figure 7-18: Longitudinal Section, Alto de Arana Vein, Alto de Arana Area, San Dimas			67
Figure 7-19: Longitudinal section, Santa Regina - San Vicente Vein, San Vicente Area, San Dimas			68
Figure 8-1: Genetic Model for Epithermal Deposits			71
Figure 8-2: Geochemical Zonation model San Dimas			72
Figure 8-3: Example Section of the Favourable Zone for Mineralization, San Dimas			73
Figure 9-1: Location of Exploration Activities within the San Dimas Property			74
Figure 9-2: San Dimas Property, Areas Explored since 2020			75
Figure 9-3: Geological Map of the San Dimas Property			76
Figure 9-4: Geological Map, Ventanas Area			77
Figure 9-5: Geology Map generated during normal course of operation, Perez Vein			78
Figure 9-6: Surface rock chip sampling, silver results map, San Dimas			79
Figure 9-7: Geological Map and Gold-Equivalent Anomalies, Ventanas Area			80

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

Figure 9-8: Magnetic Field Reduced to Pole, San Dimas			82
Figure 9-9: Satellite Image Magnetic Tilt Derivative Inversion and Alteration, San Dimas			83
Figure 9-10: Main Mining Tunnels and Drill Hole Traces, San Dimas			84
Figure 10-1: Plan view of drilling at San Dimas			87
Figure 10-2: Vertical Section, Perez Vein			88
Figure 11-1: Example of 2024 High-Grade SRM Gold and Silver Standard Charts, San Dimas Laboratory			98
Figure 11-2: Example of 2024 Time Sequence Pulp Blank Performance Charts, San Dimas Laboratory			100
Figure 11-3: Between-Laboratory Bias Check, San Dimas and SGS Laboratories			102
Figure 13-1: Typical Distribution of Minerals			108
Figure 13-2: Comparison of Au Extractions Between Mill and Laboratory Performances			110
Figure 13-3: Comparison of Ag Extractions Between Mill and Laboratory Performances			111
Figure 13-4: Pérez Domain – Drilling Program			112
Figure 13-5: Comparison of Au Extractions Between Perez 1 & Perez 2			112
Figure 13-6: Comparison of Ag Extractions Between Perez 1 & Perez 2			113
Figure 13-7: Historical Monthly Metallurgical Recovery of Gold and Silver from January 2021 to January 2025			114
Figure 13-8: San Dimas Box Plot of Gold Head Grades 2023			115
Figure 13-9: San Dimas Box Plot of Gold Recoveries Grades 2023			115
Figure 13-10: San Dimas Box Plot of Silver Head Grades 2023			116
Figure 13-11: San Dimas Box Plot of Silver Recoveries 2023			116
Figure 13-12: San Dimas Box Plot of Gold Head Grades 2024			117
Figure 13-13: San Dimas Box Plot of Gold Recoveries 2024			117
Figure 13-14: San Dimas Box Plot of Silver Head Grades 2024			118
Figure 13-15: San Dimas Box Plot of Silver Recoveries 2024			118
Figure 13-16: San Dimas Monthly Historical Doré Purity (Gold + Silver), 2021–2024			119
Figure 14-1: San Dimas Drill Hole and Sample Data Location, Plan View			122
Figure 14-2: San Dimas Drill Hole and Sample Data Location, Plan View of Ventanas Mine Area			122
Figure 14-3: Plan-view Location of Estimation Domains by Mine Zone			123
Figure 14-4: Faulted Geological Model for the Perez Vein, Vertical and Plan Views			124
Figure 14-5: Example of Hard Boundary Contact Analysis for Silver for the Perez Vein			125
Figure 14-6: Sample Interval Lengths, Composited vs. Uncomposited, Perez Vein			126
Figure 14-7: Global Capping Analysis for Gold Composite Samples for the Perez Vein with capping at 5,785 g/t			127
Figure 14-8: Box and Whisker Plots for Gold and Silver declustered composite statistics for resource domains in the West Block			129
Figure 14-9: Variogram Model for the Perez Vein			130
Figure 14-10: Block Model Estimation Passes for the Perez Domain, Vertical Section			132
Figure 14-11: Perez Ag g/t Block Model and Composite Sample Values, Vertical Section			133
Figure 14-12: Perez Au g/t Block Model and Composite Sample Values, Vertical Section			134
Figure 14-13: Swath Plot in X across the Perez Vein, Ag Values			135
Figure 14-14: Swath Plot in Y across the Perez Vein, Ag Values			135
Figure 14-15: Swath Plot in Z across the Perez Vein, Ag Values			136

 

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Figure 14-16: San Dimas Mine Block Model Ag and Au Estimates (yellow) compared to mine reported production (green) on a monthly basis over a 12-month period ending December 15, 2024			137
Figure 14-17: Measured, Indicated, and Inferred Mineral Resource Confidence Assignments, Perez Vein			139
Figure 15-1: MSO Mineable Shapes for the Perez Vein			148
Figure 15-2: Schematic Example of Dilution			150
Figure 15-3: Dilution and Mining Loss (longhole mining methods)			151
Figure 15-4: Dilution and Ore Loss (cut-and-fill mining method)			152
Figure 16-1: San Dimas Mining Areas			156
Figure 16-2: Typical Ground Support Patterns			158
Figure 16-3: Perez Vein Development and Production			159
Figure 16-4: Cut-and-Fill Long Section Schematic			161
Figure 16-5: Schematic of Longhole Stoping			162
Figure 16-6: Section of Typical Drill Layout for a Production Stope			163
Figure 16-7: Longhole Uphole Stope Section			164
Figure 16-8: Ore Development Blast Drill Plan			165
Figure 16-9: Ventilation System			167
Figure 16-10: Pumps Station Typical Arrangement			170
Figure 17-1: San Dimas Schematic Crushing Plant Flowsheet			176
Figure 17-2: San Dimas Processing Plant Flowsheet			176
Figure 18-1: San Dimas Infrastructure Map			182
Figure 18-2 : Waste Rock Storage Facility			184
Figure 18-3: Filtered Tailings Storage Facility – Overall Plan Site			186
Figure 18-4: Las Truchas Hydroelectric Plant			187
Figure 18-5: San Dimas Energy Consumption			188

 

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1.

SUMMARY

 

1.1.	Introduction

The San Dimas Silver/Gold Mine (San Dimas) is owned and operated by Primero Empresa Minera, S.A. de C.V. (Primero Empresa), which is an indirectly wholly owned subsidiary of First Majestic Silver Corp. (First Majestic). First Majestic acquired San Dimas from Primero Mining Corp. in May 2018. San Dimas operations consist of an operating underground mine, a processing plant, and tailings management facilities (TMF).

The Technical Report provides information on Mineral Resource and Mineral Reserve estimates, as well as mine and process operations and planning. The Mineral Resource and Mineral Reserve estimates are reported in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral Resources and Mineral Reserves (May 2014; the 2014 CIM Definition Standards).

The effective date of the Mineral Resource and Mineral Reserve estimates presented in this Technical Report is December 31, 2024, which represents the cut-off date for the most relevant scientific and technical information used in the Report. The effective date for this Technical Report is August 31, 2025.

In the opinion of the undersigned Qualified Person(s) (QP), the scientific and technical information contained in this Technical Report is current as of the Technical Report’s effective date. The Mineral Resource and Mineral Reserve estimates are supported by data and interpretations valid as of December 31, 2024, and no material changes have occurred between that date and the Technical Report’s effective date that would impact the conclusions herein.

This Technical Report has been prepared by employees of First Majestic under the supervision of Gonzalo Mercado, P.Geo., Vice President of Exploration and Technical Services, David Rowe, CPG, Director of Mineral Development, Michael Jarred Deal, RM SME, Vice President of Metallurgy & Innovation, Andrew Pocock, P.Eng., Director of Reserves, and Ms. María Elena Vázquez Jaimes, P. Geo., Geological Database Manager.

 

1.2.	Property Description, Location and Access

San Dimas is an actively producing mining complex located near the town of Tayoltita on the borders of the States of Durango and Sinaloa, approximately 125 km northeast of Mazatlán, Sinaloa. The mine is operated by First Majestic’s indirectly wholly owned subsidiary Primero Empresa Minera, S.A. de C.V. (Primero Empresa).

Mining operations can be conducted year-round.

 

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San Dimas consists of 119 individual concessions covering 71,867 ha in total that have been organized into six groups of concessions: the San Dimas, Candelero, Ventanas, Lechuguillas, Cebollas and Truchas concessions groups.

In 2013, the Mexican Federal government introduced a mining royalty, effective January 1, 2014, based on 7.5% of taxable earnings before interest and depreciation. In addition, precious metal mining companies must pay a 0.5% royalty on revenues from gold, silver, and platinum. In 2025, the Mexican Federal Government amended the law and increased the rights from 7.5% to 8.5% of the taxable earnings before interest and depreciation and from 0.5% to 1% royalty on revenues from gold, silver, and platinum.

First Majestic is party to a purchase (streaming) agreement with Wheaton Precious Metals which entitles Wheaton Precious Metals to receive 25% of the gold equivalent production from the San Dimas mine converted at a fixed exchange ratio of silver to gold at 70 to 1 in exchange for ongoing payments equal to the lesser of $639.91 per ounce (as of December 31, 2024, increasing every May 10th by 1%) and the prevailing market price for each gold equivalent ounce delivered under the agreement. The exchange ratio includes a provision to adjust the gold to silver ratio if the average gold to silver ratio moves above or below 90:1 or 50:1, respectively, for a period of six months. Effective April 30, 2025, the six-month average gold/silver price ratio reached 90:1 and therefore the payable gold equivalent reference to 70 was amended to 90.

Surface rights in Mexico are separate from mineral rights. First Majestic (and its predecessor companies) secured surface rights by either acquisition of private and public land or by entering into temporary occupation agreements with surrounding Ejido communities. The surface right agreements in place with the communities provide for use of surface land for exploration activities and mine-related ventilation infrastructure. Current agreements cover the operation for the Life of Mine (LOM) plan presented in the Report.

The Company has material permits for the current operations. The Company is waiting on final resolution documents for select new environmental permits requested to the competent authorities in connection with specific projects/upgrades.

San Dimas is located near the town of Tayoltita, a town with approximately 10,000 inhabitants. Access to San Dimas is by air or road from the city of Durango and Mazatlán. Flights from either Mazatlán or Durango to the town of Tayoltita require approximately 40 minutes. Road access from Durango is through a 112 km paved road plus 120 km service road to Tayoltita, this trip requires about six and a half hours. Road access from Mazatlán is through a newly constructed ~240km paved road, this trip requires approximately 4 hours to complete.

Mining activities throughout San Dimas are performed by a combination of First Majestic personnel and contract workers.

Water for the mining operations is obtained from wells, underground dewatering, recycled from processing activities and from the Piaxtla River. The main infrastructure consists of roads, a townsite, an

 

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airport, the Tayoltita mill crushing and processing facilities, the Tayoltita/Cupias dry-stack tailings facilities, the Las Truchas hydroelectric generation facilities, four LNG 1 MW generators recently installed in 2025, and a backup portable diesel power generation site. The main administrative offices and employee houses, the warehouses, assay laboratory, core shack and other facilities are located in Tayoltita.

San Dimas is located in the central part of the Sierra Madre Occidental, a mountain range characterized by rugged topography with steep, often vertical, walled valleys, and narrow canyons. Elevations vary from 2,400 metres above mean sea level (masl) on the high peaks to elevations of 400 masl in the valley floor of the Piaxtla River.

 

1.3.

History

The San Dimas property contains a series of epithermal gold silver veins that have been mined intermittently since 1757. Modern mining began in the 1880s, by the American-owned San Luis Mining Company and the Mexican-owned Candelaria Company.

In 1961, Minas de San Luis, a company owned by Mexican interests, acquired 51% of the San Dimas group of properties and assumed operations of the mine. In 1978, the remaining 49% interest in the mine was obtained by Luismin S.A. de C.V (Luismin). In 2002, Wheaton River Minerals Ltd. (Wheaton River) acquired the property from Luismin and in 2005 Wheaton River merged with Goldcorp Inc. (Goldcorp). Under its prior name Mala Noche Inc., Primero Mining Corp. (Primero) acquired San Dimas from subsidiaries of Goldcorp in August 2010. In May 2018, First Majestic acquired 100% interest in San Dimas property through acquisition of Primero.

Historical production through December 2024 from San Dimas is estimated at more than 766 Moz of silver and more than 11.1 Moz of gold, placing the district third in Mexico for precious metal production after Pachuca and Guanajuato. The majority of this production was prior to First Majestic’s acquisition of the property. The average production rate by First Majestic during 2019–2024 was approximately 2,100 tonnes per day (tpd).

 

1.4.	Geological Setting, Mineralization and Deposit Types

The San Dimas property is located in the central part of the Sierra Madre Occidental (SMO), near the Sinaloa-Durango state border, which has an average elevation exceeding 2000 m above sea level, extending from the Mexico-US border to the Trans-Mexican Volcanic Belt. Numerous epithermal deposits have been found along the SMO.

The SMO consists of Late Cretaceous to early Miocene igneous rocks including two major volcanic successions totalling approximately 3,500 m in thickness and are separated by erosional and depositional unconformities: the Lower Volcanic Complex (LVC) and Upper Volcanic Group (UVG).

 

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The LVC consists of predominantly intermediate volcanic and intrusive rocks formed between approximately 100 and 50 Ma. The LVC has traditionally been divided into local geological units based on field observations. The lower part of the sequence consists of the more than 700 m thick Socavón rhyolite, which is host to several productive veins in the district. This overlain by the Buelna andesite and the Portal Rhyolite which range from 50-250 m in thickness.

The lower sequence of rhyolitic rocks is unconformably overlain by a succession of andesitic lava flows and volcanogenic sedimentary rocks including the Productive Andesite (> 750 m thick), Las Palmas rhyo-andesite tuffs and flows (>300 m thick), and the volcanogenic sedimentary unit the Camichin Unit.

The UVG sits unconformably on the LVC and consists of the lower Guarisamey andesite and the Capping Rhyolite. The Capping Rhyolite consists of rhyolitic ash flows and air-fall tuffs and may reach as much as 1,500 m in thickness in the eastern part of the district.

The LVC and UVG volcanic rocks are intruded by intermediate rocks, consisting of the Arana intrusive andesite and the Arana intrusive diorite, and a felsic suite comprising the Piaxtla granite and the Santa Lucia, Bolaños, and Santa Rita dikes. The basic dikes intrude both the LVC and the UVG.

The most prominent structures are major north–northwest-trending normal faults with opposite vergence that divide the district into five fault-bounded blocks that are tilted to the east–northeast or west–northwest. East–west to west–southwest–east–northeast striking fractures, perpendicular to the major normal faults, are often filled by quartz veins, dacite porphyry dikes, and pebble dikes. The veins are generally west–southwest–east-northeast-oriented, within a corridor approximately 10 km wide. The veins are often truncated by the north–northwest–south–southeast-trending major faults, separating the original veins into segments. These segments are named as individual veins and grouped within the mine zones by fault block.

The mine zone groupings of veins are, from west to east: West Block, Graben Block, Central Block, Tayoltita Block, Alto de Arana Block (also known as Arana HW), San Vicente, El Cristo and Santa Rita.

Three deformational events are related to the development of the major faults, hydrothermal veins, and dikes.

Within the San Dimas property, the mineralization is typical of epithermal vein structures with banded and drusy textures. Epithermal-style veins occupy east–west-trending fractures, except in the southern part of the Tayoltita Block where they strike mainly northeast, and in the Santa Rita area where they strike north–northwest. The metal rich stage consists primarily of white to light grey, medium-to-coarse-grained crystalline quartz. The quartz contains intergrowths of base metal sulphides (sphalerite, chalcopyrite, and galena) as well as pyrite, argentite, polybasite, stromeyerite, native silver, and electrum.

Mine geologists observed that bonanza grades along the San Luis vein in the Tayoltita Block were spatially related to the Productive andesite unit and/or to the interface between the Productive andesite and the Portal rhyolite and/or the Buelna andesite. This spatial association of vein-hosted mineralization with a

 

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favorable host-rock zone within the volcanic sequence is now recognized in other fault blocks and constitutes a major exploration criterion for the district.

More than 125 mineralized quartz veins have been recognized across the San Dimas property. The silver and gold rich quartz veins have been followed underground from a few metres in strike-length to more than 1,500 m. One of these veins, the Jessica Vein, extends for more than 1,000 m in the Central Block. The vein-hosted mineral deposits within the San Dimas district are considered to be examples of silver- and gold-bearing epithermal quartz veins that formed in a low-sulphidation setting.

 

1.5.	Exploration

The San Dimas property has been the subject of modern exploration and mine development activities since the early 1970s, and a considerable information database has been developed from both exploration and mining activities. Exploration uses information from surface and underground mapping, sampling, and drilling together with extensive underground mine tunneling to help identify targets. Other exploration activities include prospecting, geochemical surface sampling, geophysical, predictive artificial intelligence, and remote sensing surveys.

Most of the exploration activities carried out within the San Dimas property were centered around the Piaxtla River where exposures of silver–gold veins were found. Outside of this area, the Lechuguilla and Ventana areas were explored to some extent during 2008 and 2015–16. The remainder of the property had limited exploration due to post-mineral cover by a thick layer of ignimbrites.

The exploration potential remains open in the areas surrounding the mine zones. As the mine was developed to the north, new veins were found. South of the Piaxtla River, the El Cristo area has potential for new quartz vein discoveries. The West Block is currently being explored by drilling and tunnelling. Opportunities to intercept the projection of fault-offset quartz veins from the Graben Block are considered good.

 

1.6.

Drilling

Drilling in the San Dimas property is focused on the identification and delineation of vein-hosted silver and gold resources by using structural and stratigraphic knowledge of the district, and preferred vein trends. Since the “favourable horizon” for mineral deposits concept emerged in 1975, the exploration drilling strategy has focused on core drilling perpendicular to the preferred vein orientation within the mine zones, which has proven to be the most effective method of exploration in the area. Core drilling is predominantly done from underground stations, as the rugged topography and the great drilling distance from surface locations to the target(s) makes surface drilling challenging and expensive. Over 1,413,000 m of core drilling has been completed since 2000.

 

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1.7.	Sampling, Analysis and Data Verification

Diamond drill core is delivered to the core logging facility where San Dimas geologists select and mark sample intervals according to lithological contacts, mineralization, alteration, and structural features.

Drill core intervals selected for sampling are cut in half using a diamond saw. One half of the core is retained in the core box for further inspection and the other half is placed in a sample bag. For smaller diameter delineation drill core (TT-46) “termite” the entire core is sampled for analysis.

The sample number is printed with a marker on the core box beside the sampled interval, and a sample tag is inserted into the sample bag. Sample bags are tied with string and placed in rice bags for shipping.

Since 2013, underground mine production channel samples for ore control and channel samples for resource estimation have been collected at San Dimas. Earlier channel samples were taken either across the roof of developments or across the face in developments. From 2016 to present, production channel samples for ore control and channel samples for resource estimation are routinely taken across the mine development face and within stopes.

Bulk density measurements are systematically taken on drill core. From 2016 to 2023, specific gravity measurements were collected on 10 cm or longer whole core vein samples using the unsealed water immersion method. Based on this method, an average bulk density value of 2.6 t/m3 was determined.

Quality control samples such as duplicates, checks and standards are included with all samples.

Since 2004, four different laboratories have been used for sample preparation and analysis. These include, First Majestic’s San Dimas Laboratory, SGS Durango, ALS-Chemex Zacatecas, and First Majestic’s ISO9001 certified Central Lab facility located at the Company’s Santa Elena operation in Sonora, Mexico.

Channel samples and drill core samples were dried, crushed, and pulverized.

In general, samples were analyzed for gold by a 30 g FA atomic absorption spectroscopy (AAS) method. Silver was analyzed by a 2 g, three-acid digestion AAS method. A multi-element suite was analyzed by a 0.25 g, aqua regia digestion inductively coupled plasma (ICP) optical emission spectroscopy (OES) method.

From 2013 to 2018, the QAQC program for the San Dimas laboratory samples included insertion of a standard reference material (SRM) and a blank in every batch of 20 samples. From 2013 to 2018, the QAQC program for channel and core samples included insertion of a SRM and a blank in every batch of 20 samples. In 2013, 5% of the coarse reject and pulp duplicates from core samples were randomly selected for analysis at SGS Durango and 5% of pulp checks from core samples were analyzed at ALS laboratory. Since 2022, the QAQC samples inserted in the core sampling include field, coarse reject, and pulp duplicates, CRMs, and coarse and pulp blanks.

The data verification included data entry error checks, visual inspections of data, and a review of QA/QC assay results was completed. Several site visits were completed as part of the data verification process. No significant differences were observed.

 

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1.8.	Mineral Processing and Metallurgical Testing

San Dimas operation is made up of several operating underground mines within the property boundaries, which all feed a central milling operation. The metallurgical test work data used to support the initial plant design has been consistently validated and reinforced by years of operational results, complemented by more recent metallurgical studies. Metallurgical testing and mineralogical investigations are routinely conducted to support ongoing performance optimization. The plant continuously performs tests to optimize metal recoveries and reduce operating costs, even when current performance falls within expected parameters. This test work is conducted by the on-site metallurgical laboratory.

The metallurgical recovery projections outlined in the LOM plan are supported by the historical performance of the processing plant and metallurgical testing of future ore. Based on plant performance data from 2021 to 2024, the estimated metal recoveries for the LOM plan and financial analysis are 92.6% for silver and 95.6% for gold. The last two years (2023 and 2024) were used in the LOM based on future material type and corresponding metallurgical testing. San Dimas doré consistently exceeds 97% purity (Au + Ag) and incurs no refinery penalties. Since March 2023, purity has surpassed 98% due to process improvements, including higher-purity zinc powder and optimized flux blends.

 

1.9.	Mineral Resource and Mineral Reserve Estimates

 

1.9.1.

Mineral Resource Estimates

The geological modelling, data analysis, and block model Mineral Resource estimates for San Dimas were completed under the supervision of David Rowe, CPG, a First Majestic employee.

The block model Mineral Resource estimates are based on the database of exploration drill holes and production channel samples, underground level geological mapping, geological interpretations and models, as well as surface topography and underground mining development wireframes available as of the December 31, 2024, cut-off date for scientific and technical data supporting the estimates.

Exploratory data analysis was completed for gold and silver assay sample values to assess the statistical and spatial character of the sample data. Boundary analysis was completed to review the change in metal grade across the domain contacts Hard boundaries were used during the creation of composite samples during mineral resource estimation.

To assess the statistical character of the composite samples within each of domains, data were declustered to account for over-sampling in certain regions. The selected composite sample length varied by domain with the most common composite sample length being 1.0 m. The assay sample intervals were composited within the limits of the domain boundaries and then tagged with the appropriate domain code. Drill hole and channel composite samples were evaluated for high-grade outliers and those outliers were capped to values considered appropriate for each domain.

 

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Mineral Resources were estimated into sub-block models rotated parallel to the resource domain trend. Parent block grades were estimated using inverse distance weighting interpolation. The block estimates were made with multiple passes to limit the influence the channel production samples at longer ranges. Pass 1 was a restrictive short-range pass that used channel and drill hole composite samples, and subsequent less restrictive passes used drill hole samples only. An average bulk density value of 2.6 t/m3 was used in estimation for all resource domains.

Validation was completed for each of the resource estimation domains in multiple steps including visual inspection, global grade bias checks, and swath plots. Overall, the block model validations demonstrated that the current Mineral Resource estimates are a reasonable representation of the primary input sample data. The Mineral Resource estimates were classified into Measured, Indicated, or Inferred based on the confidence in the geological interpretation and models, the confidence in the continuity of metal grades, the sample support for the estimation and reliability of the sample data, and on the presence of underground mining development providing detailed mapping and production channel sample support.

The Mineral Resource estimates were evaluated for reasonable prospects for eventual economic extraction by application of input parameters based on mining and processing information from the last 2 years of operations. Deswik Stope Optimizer software was used to identify the blocks representing mineable volumes that exceed the cut-off value while complying with the aggregate of economic parameters.

The Mineral Resource estimates for San Dimas are summarized in

 

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Table 1-1 and Table 1-2 using a Net Smelter Return (NSR) cut-off value of $174/t. Measured and Indicated Mineral Resources are reported inclusive of Mineral Reserves and have an effective date of December 31, 2024. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.

 

 

 

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Table 1-1: San Dimas Measured and Indicated Mineral Resource Estimate

(effective date December 31, 2024)

 

Category / Area		Mineral Type		Tonnage				Grades												Metal Content
				k tonnes				Ag (g/t)				Au (g/t)				Ag-Eq (g/t)				Ag (k Oz)				Au (k Oz)				Ag-Eq (k Oz)
Measured Central Block		Sulphides			1,169				355				4.79				778				13,320				180				29,240
Measured Sinaloa Graben		Sulphides			478				360				4.84				789				5,540				74				12,120
Measured Other Areas		Sulphides			205				399				3.80				735				2,630				25				4,850
Total Measured		Sulphides			1,851				361				4.69				776				21,490				279				46,210
Indicated Central Block		Sulphides			1,326				248				2.79				494				10,550				119				21,070
Indicated Sinaloa Graben		Sulphides			543				245				3.07				517				4,280				54				9,030
Indicated Tayoltita		Sulphides			158				326				4.04				684				1,660				21				3,480
Indicated Other Areas		Sulphides			997				335				3.00				600				10,730				96				19,240
Total Indicated		Sulphides			3,025				280				2.97				543				27,220				289				52,820
M+I Central Block		Sulphides			2,494				298				3.72				627				23,870				299				50,300
M+I Sinaloa Graben		Sulphides			1,021				299				3.90				645				9,820				128				21,160
M+I Tayoltita		Sulphides			158				326				4.04				684				1,660				21				3,480
M+I Other Areas		Sulphides			1,202				346				3.14				623				13,360				121				24,080
Total M+I		Sulphides			4,876				311				3.63				632				48,710				569				99,020

Table 1-2: San Dimas Inferred Mineral Resource Estimate (effective date December 31, 2024)

 

Category / Area		Mineral Type		Tonnage				Grades												Metal Content
				k tonnes				Ag (g/t)				Au (g/t)				Ag-Eq (g/t)				Ag (k Oz)				Au (k Oz)				Ag-Eq (k Oz)
Inferred Central Block		Sulphides			1,897				251				3.02				518				15,330				184				31,610
Inferred Sinaloa Graben		Sulphides			526				382				5.20				842				6,470				88				14,260
Inferred Tayoltita		Sulphides			506				261				3.10				536				4,250				50				8,710
Inferred Other Areas		Sulphides			2,400				217				2.24				415				16,760				173				32,050
Total Inferred		Sulphides			5,329				250				2.89				506				42,810				495				86,630

 

(1)	Mineral Resource estimates are classified per CIM Definition Standards (2014) and NI 43-101.

 

(2)	Mineral Resource estimates are based on internal estimates with an effective date of December 31, 2024.

 

(3)	Mineral Resource estimates were supervised or reviewed by David Rowe, CPG, Internal Qualified Person for First Majestic, per NI 43-101.

 

(4)	Silver-equivalent grade (Ag-Eq) is calculated as follows:

Ag-Eq = Ag Grade + (Au Grade x Au Recovery x Au Payable x Au Price) / (Ag Recovery x Ag Payable x Ag Price).

 

(5)	Metal prices for Mineral Resources estimates were $28.0/oz Ag and $2,400/oz Au. Metallurgical recovery used was 92.6% for silver and 95.6% for gold. Metal payable used was 99.95% for silver and gold.

 

(6)	NSR cutoff value considered to constrain resources assumed an underground operation was $174/t and was based on actual and budgeted operating and sustaining costs.

 

(7)	Mineral Resources are reported within mineable stope shapes using the NSR cutoff value calculated using the stated metal prices and metal recoveries. The NSR cutoff includes mill recoveries and payable metal factors appropriate to the existing processing circuit.

 

(8)	No dilution was applied to the Mineral Resource which are reported on an in-situ basis.

 

(9)	Tonnage is expressed in thousands of tonnes; metal content is expressed in thousands of ounces. Totals may not add up due to rounding.

 

 

 

 

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(10)	Measured and Indicated Mineral Resources are reported inclusive of Mineral Reserves. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.

Risk factors that may materially impact the Mineral Resource estimates include: changes to the assumptions used to generate the NSR cut-off value including metal price and exchange rates; changes to interpretations of mineralization geometry and continuity; changes to geotechnical, mining, and metallurgical recovery assumptions; assumptions as to the continued ability to access the site, retain mineral and surface rights titles, maintain environment and other regulatory permits, and maintain the social license to operate.

 

1.9.2.

Mineral Reserve Estimates

The Mineral Reserves estimation process consists of converting Mineral Resources into Mineral Reserves by identifying material that exceeds the mining cut-off grades and conforms to the geometrical constraints defined by the selected mining method. Modifying factors, such as mining methods, mining recovery, dilution, sterilization, depletion, cutoff grades, geotechnical conditions, metallurgical factors, infrastructure, operability, safety, environmental, regulatory, saleability of products, social and legal factors. These factors were applied to produce mineable stope shapes. If the Mineral Resources comply with the previous constraints, Measured Resources could be converted to Proven Reserves and Indicated Resources could be converted to Probable Reserves, in some instances Measured Resources could be converted to Probable Reserves if any or more of the modifying factors reduces the confidence of the estimates.

The NSR is the variable that was used as indicator to segregate if the revenue from the mineralized material in a block, which is part of the Measured and Indicated Mineral Resources, exceeds the operating and capital costs. NSR formulas were derived from the assumed economic parameters shown in

Table 1-3.

Table 1-3: Economic Parameters assumed for calculation of NSR

 

Concept		Units		Values
Metal Price Ag		$/oz Ag			26.00
Metal Price Au		$/oz Au			2,200
Metallurgical Recovery Ag		%			92.60
Metallurgical Recovery Au		%			95.60
Metal Payable Ag and Au		%			99.95
Dore Transport Cost		$/oz Dore			0.166
Insurance and Representation Cost		$/oz Dore			0.046
Refining Change Ag		$/oz Ag			0.225
Refining Change Au		$/oz Au			0.500

Three types of cut-off values (COV) have been determined for San Dimas: general COV, incremental COV, and marginal COV. The COVs are expressed in $/tonne, reflecting the value that the run-of-mine (ROM) material will carry before is fed to the processing plant.

 

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The planned dilution assumes a minimum mining width, which will depend on the applied mining method. The minimum mining width for cut-and-fill using jackleg drills was 0.8 m, while when using jumbo drills was 3.5 m. In the case of longhole mining, the minimum mining width assumed was 1.2 m.

The estimated overbreak in each side of the designed stope is 0.2 m for the two mining methods, longhole and cut-and-fill. An extra dilution from the backfill floor of 0.3 m for longhole and 0.2 m for cut-and-fill is also assumed. The unplanned dilution assumed was an additional 8% of the extracted material before becoming plant-feed.

Other than for sill mining, average mining loss throughout each mining block for both cut-and-fill and longhole mining has been assumed to be 5%. A factor of 25% has been used for sill pillars.

San Dimas Mineral Reserves are presented in Table 1-4.

 

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Table 1-4: San Dimas Mineral Reserves Statement (Effective Date December 31, 2024)

 

Category / Area		Mineral Type		Tonnage				Grades												Metal Content
				k tonnes				Ag (g/t)				Au (g/t)				Ag-Eq (g/t)				Ag (k Oz)				Au (k Oz)				Ag-Eq (k Oz)
Proven Central Block		Sulphides			780				255				3.47				557				6,390				87				13,980
Proven Sinaloa Graben		Sulphides			293				222				2.67				455				2,090				25				4,290
Proven Tayoltita		Sulphides			0				0				0.00				0				0				0				0
Proven Other Areas		Sulphides			184				297				2.65				528				1,750				16				3,120
Total Proven		Sulphides			1,257				253				3.16				529				10,230				128				21,390
Probable Central Block		Sulphides			732				228				2.74				467				5,370				65				11,010
Probable Sinaloa Graben		Sulphides			381				211				2.66				443				2,580				33				5,430
Probable Tayoltita		Sulphides			133				206				2.74				445				880				12				1,900
Probable Other Areas		Sulphides			726				275				2.48				492				6,420				58				11,470
Total Probable		Sulphides			1,972				241				2.63				470				15,250				167				29,810
P+P Central Block		Sulphides			1,512				242				3.11				514				11,760				151				24,990
P+P Sinaloa Graben		Sulphides			674				216				2.67				448				4,670				58				9,720
P+P Tayoltita		Sulphides			133				206				2.74				445				880				12				1,900
P+P Other Areas		Sulphides			910				279				2.51				499				8,170				74				14,590
Total P+P		Sulphides			3,229				245				2.84				493				25,480				294				51,200

 

(1)	Mineral Reserves are classified per CIM Definition Standards (2014) and NI 43-101.

 

(2)	Mineral Reserves are effective December 31, 2024, are derived from Measured & Indicated Resources, account for depletion to that date, and are reported with a reference point of mined ore delivered to the plant.

 

(3)	Mineral Reserve estimates were supervised or reviewed by Andrew Pocock, P.Eng., Internal Qualified Person for First Majestic per NI 43-101.

 

(4)	Silver-equivalent grade (Ag-Eq) is calculated as follows:

Ag-Eq Grade = Ag Grade + Au Grade *(Au Recovery * Au Payable * Au Price) / (Ag Recovery * Ag Payable * Ag Price)

 

(5)

Metal prices for Reserves: $26/oz Ag, $2,200/oz Au. Other key assumptions and parameters include Metallurgical recoveries of 92.6% Ag, 95.6% Au; metal payable of 99.95% Ag & Au, costs ($/t): direct mining $61.91 longhole stoping and $96.55 cut & fill, processing $39.37 mill feed, indirect/G&A $65.51 and sustaining $35.88 for longhole stoping and cut & fill.

 

(6)

A two-step cutoff approach was used per mining method: A general cutoff grade defines mining areas covering all associated costs; and a 2nd pass incremental cutoff includes adjacent material covering only its own costs, excluding shared general development access & infrastructure costs which are covered by the general cutoff material.

 

(7)

Modifying factors for conversion of resources to reserves include but are not limited to consideration for mining methods, mining recovery, dilution, sterilization, depletion, cutoff grades, geotechnical conditions, metallurgical factors, infrastructure, operability, safety, environmental, regulatory, social, and legal factors. These factors were applied to produce mineable stope shapes.

 

(8)	Tonnage in thousands of tonnes, metal content in thousands of ounces, prices/costs in USD. Numbers are rounded per guidelines; totals may not sum due to rounding.

The QP is not aware of any known mining, metallurgical, environmental, permitting, legal, title, taxation, socio-economic, marketing, political, or other relevant factors that could materially affect the Mineral Reserve estimates, other than discussed herein.

 

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1.10.

Mining Operations

San Dimas includes five underground gold and silver mining areas: West Block (San Antonio, Perez mine), Sinaloa Graben Block (Graben Block), Central Block, Tayoltita Block, and the Arana Hanging-wall Block (Santa Rita mine).

Both First Majestic and contractor personnel conduct mining activities. Two mining methods are currently being used at San Dimas, cut-and-fill, and Longhole mining. Cut-and-fill is carried out by either jumbo or jackleg drills, whereas Longhole is carried out with pneumatic and electro-hydraulic drills. Primary access is provided by adits and internal ramps.

Ground conditions throughout most of the San Dimas underground workings are considered good. Bolting is used systematically in the main haulage ramps, drifts, and underground infrastructure. For those sectors that present unfavorable rock quality, shotcrete, mesh, and/or steel arches are used.

Groundwater inflow has not been a significant concern within San Dimas. Dewatering systems in San Dimas consist of main and auxiliary pumps in place at each of the mine areas.

The San Dimas ventilation system consists of an exhaust air extraction system through its main fans located on surface. These fans generate the necessary pressure change for fresh air to enter through the portals and ventilation raises.

The development schedule for the LOM plan is presented in Table 1-5. The production schedule for the LOM plan is presented in

 

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Table 1-6.

Table 1-5 San Dimas Life of Mine Development Schedule

 

Type		Units		Size (m)		2025				2026				2027				2028				2029				Total
Main Access Ramp		m		4.5x4.5			2,378				2,385				2,385				2,578				586				10,313
Main Level Access		m		4.5x4.5			2,101				2,107				2,107				2,277				518				9,109
Ancillary		m		3.5x3.5			1,229				1,232				1,232				1,332				303				5,328
Drifting for Exploration		m		4.5x4.5			1,821				1,826				1,826				2,016				469				7,958
Ventilation Raises		m		2.5 diam			1,009				1,067				580				446				51				3,153
Total Waste Development		m					8,538				8,617				8,130				8,649				1,926				35,860
Ore Development		m		3.5x3.5			6,783				6,802				6,802				6,326				3,353				30,066
Total Development		m					15,321				15,418				14,932				14,975				5,279				65,926

 

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Table 1-6 San Dimas Life of Mine Production Schedule

 

Type		Units		2025				2026				2027				2028				2029				Total
ROM Production / Plant Feed		kt			629				631				631				630				708				3,229
Silver Grade		g/t Ag			285				285				285				230				153				245
Gold Grade		g/t Au			2.83				2.83				2.83				2.83				2.86				2.84
Silver-Equivalent Grade		g/t Ag-Eq			532				532				532				477				403				493
Contained Silver		M oz Ag			5.8				5.8				5.8				4.7				3.5				25
Contained Gold		k oz Au			57				57				57				57				65				294
Contained Silver-Equivalent		M oz Ag-Eq			10.8				10.8				10.8				9.7				9.2				51
Metallurgical Recovery Silver		%			94.9	%			92.6	%			92.6	%			92.6	%			92.6	%			93.1	%
Metallurgical Recovery Gold		%			95.1	%			95.6	%			95.6	%			95.6	%			95.6	%			95.5	%
Produced Silver		M oz Ag			5.5				5.4				5.4				4.3				3.2				24
Produced Gold		k oz Au			54				55				55				55				62				281
Produced Silver-Equivalent		M oz Ag-Eq			10.2				10.1				10.1				9.1				8.7				48

A total of 3.2 Mt of ore is considered to be mined and processed with grades of 245 g/t Ag and 2.84 g/t Au. Total metal produced is estimated at 25 Moz Ag and 294 Koz Au.

 

1.11.

Recovery Methods

The San Dimas processing plant has been in successful operation for several years, consistently achieving high recoveries based on both historical performance and recent metallurgical testing. The plant operates on a conventional cyanide leaching and Merrill-Crowe process to produce silver-gold doré bars, with an installed capacity of 3,000 tpd.

The facility is designed as a single processing train, with the crushing area separated from the rest of the circuit and connected via a belt conveyor that transfers screened material to the fine-ore bins. The plant consists of the following operating units: a two-stage crushing circuit with a primary jaw crusher and a secondary cone crusher (one in operation, one standby) in closed circuit with a double-deck 8’x16’ dry vibrating screen; three ball mills operating in parallel, each with two hydrocyclones (one operational, one standby) in closed circuit; cyanide leaching in 16 agitated tanks with two intermediate thickeners; two counter-current decantation (CCD) thickeners in series; Merrill-Crowe zinc precipitation followed by smelting; and four horizontal vacuum belt filters for tailings filtration, located adjacent to the Tailings Storage Facility. This robust configuration supports high metallurgical performance and operational efficiency across the circuit.

 

1.12.

Infrastructure, Permitting and Compliance Activities

The infrastructure in San Dimas is fully developed to support current mining and mineral processing activities, with part of its facilities located in the town of Tayoltita.

The main infrastructure of San Dimas consists of access roads, the district mines, which are divided into five mining areas, crushing and processing facilities known as the Tayoltita mill, the Tayoltita/Cupias tailings facilities, an assays laboratory, offices and staff camp, the Las Truchas hydroelectric generation

 

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facilities, an LNG and diesel-powered emergency generation plant, a local airport and infrastructure supporting the inhabitants of the Tayoltita townsite including a local clinic, schools and sport facilities.

Most of the personnel and light supplies for San Dimas arrive on First Majestic’s regular flights from Mazatlán and Durango. Heavy equipment and other supplies are brought by road from Durango and Mazatlán.

Electrical power is provided by a combination of First Majestic’s own hydroelectric generation system (Las Truchas) and the Federal Power Commission supply system (CFE). First Majestic operates the hydroelectric generation plant, which is interconnected with the CFE power grid, and a series of back-up diesel generators which are being replaced by an LNG plant in 2025.

The source of water for industrial use comes mainly from mine dewatering stations and from the recycled filtered-tailings water after it has been treated. About 80% of the water required for processing activities is being treated and recycled. A project to improve water sourcing and reliability is under review and consideration for H2 2025 completion.

Environmental and social studies are routinely performed in San Dimas to characterize existing conditions and to support the preparation of Risk Assessments and Accident Prevention Programs for the operation and are documented as part of the Environmental Management System implemented by First Majestic.

San Dimas consists of several mining areas, and it holds major environmental permits and licenses required by the Mexican authorities to carry out mineral extracting activities in the mining complex.

The main environmental permit is the environmental license “Licencia Ambiental Unica” (LAU) under which the mine operates its industrial facilities in accordance with the Mexican environmental protection laws administered by SEMARNAT as the agency in charge of environment and natural resources. The most recent update to the main environmental permit was approved in April 2024.

On May 8, 2023, the Mexican Government enacted a decree amending several provisions of the Mining Law, the Law on National Waters, the Law on Ecological Equilibrium and Environmental Protection and the General Law for the Prevention and Integral Management of Waste (the “Decree”), which became effective on May 9, 2023. The Decree amends the mining and water laws, including: (i) the duration of the mining concession titles, (ii) the process to obtain new mining concessions (through a public tender). Additionally, on March 18, 2025, the new legislative framework for the hydrocarbon sector in Mexico was published in the Federal Official Gazette. This framework introduces specific permitting requirements for various hydrocarbons, including diesel.

These amendments are expected to have an impact on our current and future exploration activities and operations in Mexico, and the extent of such impact is yet to be determined but could be material for the Company. On June 7, 2023, the Senators of the opposition parties (PRI, PAN, and PRD) filed a constitutional action against the Decree, which is pending to be decided by Plenary of the Supreme Court of Justice.

 

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During the second quarter of 2023, the Company filed an amparo lawsuit, challenging the constitutionality of the Decree. As of the date of this Technical Report, these amparos filed by First Majestic, along with numerous amparos in relation to the Decree that have been filed by other companies, are still pending before the District or Collegiate Courts. On July 15, 2024, the Supreme Court of Justice in Mexico suspended all ongoing amparo lawsuits against the Decree whilst the aforementioned constitutional action is being considered by the Supreme Court.

San Dimas has implemented the First Majestic Environmental Management System, which supports the implementation of environmental policy and is applied to standardize tasks and strengthen a culture focused on minimizing environmental impacts. The EMS is based on the requirements of the international standard ISO 14001:2015 and the requirements to obtain the Certificate of Clean Industry, issued by the Mexican environmental authorities, the Ministry of Environment and Natural Resources (SEMARNAT), through the Federal Attorney for Environmental Protection in Mexico (PROFEPA). The EMS includes an annual compliance program to review all environmental obligations.

In May 2018, San Dimas received the Clean Industry Certification for improvements to its environmental management practices at the mine.

In February 2024, for the thirteenth consecutive year, San Dimas was awarded the Socially Responsible Company (ESR) designation by the Mexican Center for Philanthropy (CEMEFI).

 

1.13.

Capital and Operating Costs

San Dimas has been under First Majestic’s operation since May 10, 2018. The LOM plan includes estimates for sustaining capital expenditures for the planned mining and processing activities. Estimated sustaining capital expenditures for the LOM plan is assumed to average approximately $20 million per annum. Table 1-7 present the summary of the sustaining expenditures estimated for San Dimas.

A summary of the San Dimas operating costs resulting from the LOM plan and the cost model used for assessing economic viability is presented in Table 1-8. A summary of the annual operating expense is presented in Table 1-9.

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

Table 1-7: San Dimas Mining Sustaining Capital Costs Summary ($Million)

 

Type		Total				2025				2026				2027				2028				2029
Mine Development		$	53.5			$	12.3			$	12.3			$	12.3			$	13.4			$	3.1
Property, Plan & Equipment		$	26.8			$	5.2			$	5.2			$	5.2			$	5.2			$	5.9
Other Sustaining Cost		$	5.7			$	1.1			$	1.1			$	1.1			$	1.1			$	1.2
Total Sustaining Capital Costs		$	86.0			$	18.6			$	18.7			$	18.7			$	19.8			$	10.2
Near Mine Exploration		$	4.5			$	1.2			$	1.1			$	1.1			$	1.0
Total Capital Costs		$	90.5			$	19.8			$	19.8			$	19.8			$	20.8			$	10.2

Table 1-8: San Dimas Operating Costs

 

Type		$/tonne milled
Mining Cost		$	64.9
Processing Cost		$	38.5
Indirect Costs		$	57.1
Total Production Cost		$	160.5
Selling Costs		$	2.6
Total Cash Cost		$	163.0

 

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San Dimas Silver/Gold Mine Durango and Sinaloa States, Mexico NI-43-101 Technical Report on Mineral Resource and Mineral Reserve Estimates

 

Table 1-9: San Dimas Annual Operating Costs ($Million)

 

Type		Total				2025				2026				2027				2028				2029
Mining Cost		$	209.6			$	40.8			$	41.0			$	41.0			$	40.9			$	46.0
Processing Cost		$	124.3			$	24.2			$	24.3			$	24.3			$	24.2			$	27.3
Indirect Costs		$	184.3			$	35.9			$	36.0			$	36.0			$	35.9			$	40.4
Total Production Cost		$	518.1			$	101.0			$	101.2			$	101.2			$	101.0			$	113.7
Selling Costs		$	8.3			$	1.6			$	1.6			$	1.6			$	1.6			$	1.8
Total Cash Cost		$	526.5			$	102.6			$	102.9			$	102.9			$	102.6			$	115.5

 

1.14.

Conclusions

Under the assumptions used in this Technical Report, San Dimas has positive economics for the LOM plan, which supports the Mineral Reserve statement.

 

1.15.

Recommendations

A 110,000 m annual exploration program is recommended to identify new areas to support mineral resource conversion to higher confidence categories and to pursue new discoveries. This drill program is estimated to cost $12.0 million per year excluding related underground access development costs.

An annual prospect generation program consisting of prospecting, soil and rock geochemical surveys, mapping, and geophysical surveys is recommended, with an estimated cost of $400,000 per year.

The potential for adding oxygen to the leach circuit at San Dimas is currently under investigation as a means to improve leaching kinetics and enhance recoveries, particularly in the context of processing lower-grade and higher-sulfide ore bodies.

A coordinated, efficiency focused effort to reduce costs is recommended.

Finally, interventions in development and drill and blast practices should continue to be a focus to improve mine plan compliance and execution.

 

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