Minerals & Metals 1892-RPT-010 Revision Number 0 Technical Report on the Cerro Negro Feasibility Study Santa Cruz Province, Argentina July 20, 2010 1892-RPT-010 Rev: 0 Date: July 2010 9999FM0105 – 1 Table of Contents 1 Summary 1 1.1 Introduction 1 1.2 Exploration 2 1.3 Geology 3 1.4 Mineralization 4 1.5 Resource Estimation 4 1.6 Mineable Reserves and Mining 6 1.7 Metallurgical Testwork 7 1.8 Mineral Processing 8 1.9 Mine Geotechnical and Plant Foundations 9 1.10 Infrastructure 10 1.11 Project Implementation 14 1.12 Environmental 14 1.13 Capital and Operating Cost Estimates 15 1.14 Financial Analysis 17 1.15 Conclusions and Recommendations of Qualified Persons 18 2 Introduction and Terms of Reference 20 2.1 Introduction 20 2.2 Project Scope and Terms of Reference 20 2.3 Qualified Persons 20 2.4 Frequently Used Acronyms, Abbreviations, Definitions, and Units of Measure 21 2.5 Area Definitions and Naming Conventions Used in Report 22 3 Reliance on Other Experts 24 3.1 Qualified Persons 24 3.2 Other Experts 24 4 Property Description and Location 25 4.1 Location 25 4.2 Land Area 25 4.3 Agreements and Encumbrances 28 4.4 Environmental Liabilities and Permitting 29 5 Accessibility, Climate, Local Resources, Infrastructure and Physiography 30 5.1 Access 30 5.2 Climate 30 5.3 Local Resources and Infrastructure 31 5.4 Physiography 31 6 History 33 6.1 Exploration History of the Cerro Negro Property 33 6.2 Exploration History of Eureka Vein System 35 6.3 Exploration History of Bajo Negro 35 6.4 Exploration History of Vein Zone 35 6.5 Historical Mineral Resource Estimates 36 6.6 Mineral Reserves Estimate 39 7 Geological Setting 40 7.1 Regional Geology 40 7.2 Project Area Geology 41 1892-RPT-010 i Rev: 0 Date: July 2010 9999FM0105 – 1 8 Deposit Types 49 9 Mineralization 51 9.1 Eureka Vein System 52 9.2 Bajo Negro 54 9.3 Vein Zone 56 10 Exploration 58 10.1 Andean’s Exploration of the Cerro Negro Property 58 10.2 Eureka Vein System 61 10.3 Bajo Negro 61 10.4 Vein Zone 62 11 Drilling 65 11.1 Summary 65 11.2 Drilling by Pegasus Gold International 70 11.3 Drilling by MIM Holdings Ltd. 70 11.4 Drilling by Oroplata Pty Ltd. 70 11.5 Drilling by Andean Resources Ltd. 71 12 Sampling Method and Approach 74 12.1 Sampling by Pegasus Gold International 74 12.2 Sampling by MIM Holdings Ltd. 74 12.3 Sampling by Oroplata Pty Ltd. 74 12.4 Sampling by Andean Resources 75 13 Sample Preparation, Analyses and Security 79 13.1 Pegasus Gold International 79 13.2 MIM Holdings Ltd. 79 13.3 Drilling by Oroplata Pty Ltd. 81 13.4 Early Drilling by Andean Resources Ltd. (Phases 1 to 4) 81 13.5 Current Drilling by Andean Resources Ltd. (Phase 5) 83 14 Data Verification 87 14.1 Historic Data Verification 87 14.2 Database Management 91 14.3 Database Audit 91 14.4 Review of Quality Control and Quality Assurance (“QA/QC”) Data 94 14.5 Sample Integrity 114 14.6 MDA Independent Sampling 121 14.7 Summary Statement on Data Verification 122 15 Adjacent Properties 123 16 Mineral Processing and Metallurgical Testing 124 16.1 Historic Testing 124 16.2 Testing for the 2010 Feasibility Study 124 16.3 Testwork Samples 126 16.4 Mineralogical Examination 127 16.5 Comminution 128 16.6 Extraction – Domain Composites 130 16.7 Extraction Variability 139 16.8 Settling 141 16.9 Filtration 143 16.10 Cyanide Detoxification 144 16.11 Metallurgical Recoveries 145 1892-RPT-010 ii Rev: 0 Date: July 2010 9999FM0105 – 1 16.12 Conclusions 146 16.13 Recommendations 147 17 Mineral Resource and Mineral Reserve Estimates 148 17.1 Introduction 148 17.2 Resource Models 148 17.3 Eureka Mineral Resource Estimate 151 17.4 Bajo Negro Mineral Resource Estimate 162 17.5 Vein Zone Mineral Resource Estimate 172 17.6 Discussion of Drilling that Post-dates the Resource Estimates 188 17.7 Mineral Reserve Estimate 189 18 Other Relevant Data and Information 199 18.1 Additional Vein Systems 199 18.2 Environment and Social Aspects 199 19 Interpretation and Conclusions 200 19.1 Mineral Resource 200 19.2 Geotechnical 200 19.3 Mineral Reserve Estimates and Mining 201 19.4 Metallurgical Processing 201 19.5 Tailings Storage Facility 202 20 Recommendations 203 20.1 Geomechanical 203 20.2 Site Geotechnical 204 20.3 Mining 205 20.4 Metallurgical Processing 205 20.5 Tailings Storage Facility (TSF) 205 20.6 Risk Assessment 205 21 References 206 22 Date and Signature Pages 211 23 Additional Requirements for Technical Reports on Development Properties and Production Properties 216 23.1 Hydrogeology 216 23.2 Mining 221 23.3 Metallurgical Processing 246 23.4 Site Infrastructure 259 23.5 Tailings Management 278 23.6 Environmental and Social Impact Assessment 288 23.7 Mine and Plant Geotechnical 297 23.8 Capital Cost Estimate 322 23.9 Operating Cost Estimate 325 23.10 Operations Project Organization 341 23.11 Marketing 345 23.12 Financial Analysis 350 23.13 Project Implementation 354 1892-RPT-010 iii Rev: 0 Date: July 2010 9999FM0105 – 1 Table 1.1: Total Estimated Gold and Silver Resources for Cerro Negro 5 Table 1.2: Cerro Negro Probable Reserves 6 Table 1.3: Recoveries Selected for Financial Evaluation 7 Table 1.4: Recoveries Selected for Mineral Reserve Estimation 8 Table 1.5: Capital Cost Summary 15 Table 1.6: Total Operating Cost Summary 16 Table 1.7: Cerro Negro NPV and IRR (US$850/oz Au and US$14/oz Ag) 18 Table 2.1: Responsibilities of Each Qualified Person 21 Table 4.1: Andean’s Land Holdings for the Cerro Negro Property 28 Table 6.1: Estimated Mineralization for Vein Zone by Meldrum (1999) 37 Table 6.2: 2007 Estimated Mineral Resources for Vein Zone 37 Table 6.3: 2007 Mineral Resource Estimate for the Eureka West Zone 38 Table 6.4: 2008 Mineral Resource Estimate for the Eureka West Zone 38 Table 6.5: Estimated Mineral Resources of the Eureka West Area 39 Table 7.1: Key to Units Shown in Figure 7.4 44 Table 8.1: Conditions of Mineralizing Fluid in Selected Cerro Negro Veins 49 Table 9.1: Opaque Mineralogy and Au-Ag Grades of the Eureka Vein System 53 Table 9.2: Vein Mineralogy of the Eureka West Vein 53 Table 9.3: Vein Mineralogy of the Bajo Negro Vein 55 Table 10.1: RC and Core Holes Drilled in the Eureka Resource Area 61 Table 11.1: Eureka Drill Holes 65 Table 11.2: Bajo Negro Drill Hole Database 67 Table 11.3: Vein Zone Drill Hole Database 69 Table 13.1: Standards Statistics from MIM Sampling 80 Table 13.2: Screen Fire Assay Statistics from MIM 80 Table 13.3: MIM Check Assaying 81 Table 14.1: Analytical Standards Used with Drill Hole Samples – April 2009 96 Table 14.2: List of Standards Employed 105 Table 14.3: Summary of Gold in Standards 107 Table 14.4: Summary of Silver in Standards 107 Table 14.5: Summary of Differences in Duplicates, Gold Only 110 Table 14.6: Descriptive Statistics of the Core Recovery and RQD Data Eureka Database 115 Table 14.7: Comparison of Core and RC Sample Grades 119 Table 14.8: Descriptive Statistics of the Core Recovery and RQD Data Bajo Negro Database 120 Table 14.9: MDA Check Samples from Eureka Core 121 Table 14.10: MDA Check Samples from Bajo Negro Core 122 Table 16.1: Domain Composite Summary Head Analysis 127 Table 16.2: Variability Composite Bond Index Determination Results 128 Table 16.3: Variability Composite Bond Index Determination Results 129 Table 16.4: Cyanidation Residence Time Au Extraction 133 Table 16.5: Cyanidation Residence Time Ag Extraction 134 Table 16.6: East Composite Whole Ore Low Cyanide Leach Tests – Au Extraction 134 Table 16.7: East Composite Whole Ore Low Cyanide Leach Tests – Ag Extraction 135 Table 16.8: East Composite Whole Ore Low Cyanide Leach Tests Summary 135 Table 16.9: Varying Gravity Mass % Recovery Leach Tests 137 1892-RPT-010 iv Rev: 0 Date: July 2010 9999FM0105 – 1 Table 16.10: Whole Ore Bulk Leach 138 Table 16.11: Bajo Negro Zinc Precipitation Tests – High Temperature De-aeration 139 Table 16.12: Vein Zone Leach Test 139 Table 16.13: Summary of Variability Composite Leach Tests 140 Table 16.14: Eureka Domain Composites Dynamic Thickening Testwork Results 142 Table 16.15: Bajo Negro Domain Composites Dynamic Thickening Testwork Results 142 Table 16.16: Recoveries Selected for Financial Evaluation 145 Table 16.17: Recoveries Selected for Mineral Reserve Calculations 145 Table 17.1: Total Estimated Gold and Silver Resources for Cerro Negro 148 Table 17.2: Descriptive Statistics of the Eureka Database 152 Table 17.3: Descriptive Statistics of the Density Samples 156 Table 17.4: Eureka Classification Criteria 157 Table 17.5: Total Gold and Silver Resources for Eureka: Indicated and Inferred 158 Table 17.6: Eureka Vein and Vein-Breccia Gold and Silver Mineralization 162 Table 17.7: Descriptive Statistics of the Bajo Negro Database 163 Table 17.8: Descriptive Statistics of the Density Samples 167 Table 17.9: Classification Criteria for Bajo Negro 168 Table 17.10: Total Gold and Silver Resources for Bajo Negro: Indicated and Inferred 168 Table 17.11: Vein-Only Mineralization Subset of the Gold and Silver Resources for Bajo Negro 171 Table 17.12: Descriptive Statistics of the Vein Zone Database 172 Table 17.13: Sample Statistics – Gold 173 Table 17.14: Sample Statistics – Silver 174 Table 17.15: Descriptive Statistics of the Density Samples at Vein Zone 178 Table 17.16: Estimation Parameters for Stockwork (Low-Grade) 180 Table 17.17: Estimation Parameters for Vein Mineralization 181 Table 17.18: Estimation Parameters for Gold outside the Defined Mineral Gold Domains 182 Table 17.19: Estimation Parameters for Silver outside the Defined Mineral Silver Domains 182 Table 17.20: Classification Criteria for Vein Zone 183 Table 17.21: Total Gold and Silver Resources for Vein Zone: Indicated and Inferred 184 Table 17.22: Total Cerro Negro Reserves Summary 189 Table 17.23: Eureka SMU Dimensions and Dilution Criteria 190 Table 17.24: Eureka Economical and Metallurgical Parameters 191 Table 17.25: Eureka Reserves Summary 191 Table 17.26: Eureka Probable Reserves by Metallurgical Domain 192 Table 17.27: Bajo Negro SMU Dimensions and Dilution Criteria 192 Table 17.28: Bajo Negro Economical and Metallurgical Parameters 193 Table 17.29: Bajo Negro Reserves Summary 193 Table 17.30: Vein Zone Parameters for Pit Optimization 194 Table 17.31: Vein Zone Pit Optimization Results 195 Table 17.32: Pit Design Parameters 196 Table 17.33: Vein Zone Reserves Summary 198 Table 23.1: Mean Flow Test Results 219 Table 23.2: Bajo Negro Selective Mining Units (SMU) Dimensions and Dilution Criteria 227 Table 23.3: Pit Design Parameters 228 Table 23.4: Eureka Mine Schedule 231 1892-RPT-010 v Rev: 0 Date: July 2010 9999FM0105 – 1 Table 23.5: Bajo Negro Mine Schedule 232 Table 23.6: Vein Zone Mine Schedule 232 Table 23.7: Cerro Negro Integrated Plant Feed 233 Table 23.8: Eureka Total Development Summary 234 Table 23.9: Average Monthly Advance Rates 235 Table 23.10: Eureka Initial Development (Contractor) 235 Table 23.11: Eureka Initial Development (Owner) 235 Table 23.12: Eureka Ongoing Development (Owner) 236 Table 23.13: Bajo Negro Development (Owner) 237 Table 23.14: Design Criteria Summary for Eureka Ore 247 Table 23.15: Mobile Equipment Allocations 276 Table 23.16: Tailings Production Rate 278 Table 23.17: General Design Criteria and Parameters 279 Table 23.18: Strength properties used in Stability Analyses 281 Table 23.19: Minimum Factors of Safety for Tailings Dams 282 Table 23.20: Environmental Impacts and Mitigation Measures 293 Table 23.21: Eureka Rock Uniaxial Compressive Strength used for Stope Design 302 Table 23.22: Summary of Eureka Principal Discontinuity Orientation (Dip/Dip Direction) 302 Table 23.23: Q’ statistics for Eureka Stope Design 303 Table 23.24: Rock Mass Properties used for Eureka Stope Design 304 Table 23.25: Recommended Initial Eureka Stope Geometry, Single Lift Stoping 305 Table 23.26: Bajo Negro Rock Uniaxial Compressive Strength by Domain 308 Table 23.27: UCS per Domain used for Bajo Negro Stope Design 308 Table 23.28: Summary of Principal Bajo Negro Decline Features Orientation (Dip/Dip Direction) 308 Table 23.29: Q’ Statistics for Bajo Negro Stope Design 309 Table 23.30: Rock Mass Properties used for Bajo Negro Stope Design 310 Table 23.31: Recommended Initial Bajo Negro Stope Geometry, Single Lift Stoping Without Systematic Support 311 Table 23.32: Vein Zone Rock Mass Discontinuities Orientations 312 Table 23.33: Design Density Values Adopted for each Vein Zone Geotechnical Domain 314 Table 23.34: Fractures Spacing per Vein Zone Domain Described during Geotechnical Logging 315 Table 23.35: Uniaxial Resistance Design for each Vein Zone Domain 315 Table 23.36: Failure Criteria Strength Parameters Estimated per Vein Zone Domain 316 Table 23.37: Slope Profiles Recommended for each Vein Zone Geotechnical Domain 321 Table 23.38: Capital Cost Estimate Summary 322 Table 23.39: Capital Costs by Area (000s) 323 Table 23.40: Sustaining Capital Expenditures (000s) 325 Table 23.41: Unit Costs for Main Consumables 326 Table 23.42: Hourly Equipment Costs 326 Table 23.43: Cost per Type of Mining Activity 327 Table 23.44: Power Consumption 328 Table 23.45: Mining Costs per Period 328 Table 23.46: Total Unit Cost Breakdown – Eureka 329 Table 23.47: Total Production Volumes – Bajo Negro 329 Table 23.48: Operational Expenditures – Bajo Negro (US$000s) 330 1892-RPT-010 vi Rev: 0 Date: July 2010 9999FM0105 – 1 Table 23.49: Total Unit Cost Breakdown – Bajo Negro 330 Table 23.50: Annual Operating Costs – Vein Zone 330 Table 23.51: Equipment Annual Operating Hours – Vein Zone 331 Table 23.52: Cost per Operating Hour for Equipment (by type) 331 Table 23.53: Mine Operational Expenditures for Vein Zone per Year (US$000s) 332 Table 23.54: Vein Zone Operational Expenditures – Unit Cost (US$/t) 333 Table 23.55: Mill Production Schedule 335 Table 23.56: Cerro Negro Project Operating Cost Summary 336 Table 23.57: Operating Labour Summary 337 Table 23.58: Reagent / Consumable Operating Costs 337 Table 23.59: G&A Cost Summary 340 Table 23.60: Total Operating Cost Summary 340 Table 23.61: Forecast Annual Production 345 Table 23.62: Anticipated Product Quality 345 Table 23.63: Allowable Impurities for Major Refineries 346 Table 23.64: Doré Shipping Costs 350 Table 23.65: Cerro Negro Cash Flow Summary 351 Table 23.66: Long-Term Metal Prices 352 Table 23.67: Cerro Negro NPV and IRR (US$850/oz Au and US$14/oz Ag) 352 Table 23.68: Sensitivity Analysis 353 Figure 1-1: Location Map Showing Proximity of Eureka to El Retiro 11 Figure 1-2: Sensitivity Analysis 17 Figure 2-1: Eureka Area Definitions and Naming Conventions Used in Report 23 Figure 4-1: Location of the Cerro Negro Property 26 Figure 4-2: Mineral and Surface Tenements of the Cerro Negro Property 27 Figure 5-1: In order: Eureka, Bajo Negro and Vein Zone Areas 32 Figure 7-1: Location of the Cerro Negro Property and the Deseado Massif 40 Figure 7-2: Geology of the Deseado Massif 41 Figure 7-3: Project Area Geology, Cerro Negro Area 42 Figure 7-4: Detailed Geology of the Eureka Area 45 Figure 7-5: Structural Relationships of the Eureka Vein System 45 Figure 7-6: Detailed Geology, Bajo Negro Prospect 46 Figure 7-7: Longitudinal Grade x Thickness – 3D Projection of the Bajo Negro Vein 47 Figure 7-8: Geology of the Vein Zone Area 48 Figure 8-1: Model for Au-Ag Deposition after Leach and Corbett (2008) 50 Figure 9-1: Mineralized Areas of the Cerro Negro Property 51 Figure 11-1: Eureka Area Drill Hole Map 66 Figure 11-2: Bajo Negro Area Drill Hole Map 68 Figure 11-3: Vein Zone Area Drill Hole Map 69 Figure 14-1: Control Chart for Gold in Standard 062 97 Figure 14-2: Gold in Blanks vs. Gold in Preceding Samples, Phase 5 98 Figure 14-3: Gold in Blanks vs. Gold in Preceding Samples, Pre-Phase 5 100 1892-RPT-010 vii Rev: 0 Date: July 2010 9999FM0105 – 1 Figure 14-4: Pulp Duplicates, Gold Relative Percent Difference, Phase 5 101 Figure 14-5: Pulp Duplicates, Gold Absolute Value Relative Percent Difference, Phase 5 102 Figure 14-6: Preparation Duplicates, Gold Absolute Value Relative Percent Difference, Phase 5 103 Figure 14-7: Field Duplicates, Gold Absolute Value Relative Percent Difference, Pre-Phase 5 Core 104 Figure 14-8: Field Duplicates, Gold Absolute Value Relative Percent Difference, Pre-Phase 5 RC 105 Figure 14-9: Performance of Primary Lab on Gold in STD-036 106 Figure 14-10: Performance of Primary Lab on Gold in Blanks 108 Figure 14-11: Performance of Primary Lab on Silver in Blanks 109 Figure 14-12: Gold in Reverse-Circulation Field Duplicates 111 Figure 14-13: Gold in Core Field Duplicates 112 Figure 14-14: Gold in Preparation Duplicates 113 Figure 14-15: Gold in Pulp Duplicates 114 Figure 14-16: Core Recovery at Eureka by Gold Mineral Domains 115 Figure 14-17: RQD at Eureka by Gold Mineral Domains 116 Figure 14-18: Gold Grades by Core Recovery inside All Mineralized Zones 116 Figure 14-19: Silver Grades by Core Recovery inside All Mineralized Zones 117 Figure 14-20: Gold Grades by RQD inside the Mineralized Zones 117 Figure 14-21: Silver Grades by RQD inside the Mineralized Zones 118 Figure 16-1: Gold Residue Grade with Varying Grind 131 Figure 16-2: Silver Residue Grade with Varying Grind 131 Figure 16-3: Gold Residue Grades for Variability Samples 140 Figure 16-4: Silver Residue Grades for Variability Samples 141 Figure 17-1: Typical Section of the Eureka Gold Mineral Domains – Section 150E 154 Figure 17-2: Typical Section of the Eureka Silver Mineral Domains – Section 150E 155 Figure 17-3: Typical Section of the Gold Mineral Domains with Block Model for Eureka 159 Figure 17-4: Typical Section of the Silver Mineral Domains with Block Model for Eureka 160 Figure 17-5: Typical Section of the Bajo Negro Gold Mineral Domains – Section 250N 165 Figure 17-6: Typical Section of the Bajo Negro Silver Mineral Domains – Section 250N 166 Figure 17-7: Typical Section of the Bajo Negro Gold Mineral Domains with Block Model Section 250 169 Figure 17-8: Typical Section of the Bajo Negro Silver Mineral Domains with Block Model Section 250 170 Figure 17-9: Typical Section of the Vein Zone Gold Mineral Domains – Section 8650E 176 Figure 17-10: Typical Section of the Vein Zone Silver Mineral Domains – Section 8650E 177 Figure 17-11: Typical Section of the Vein Zone Gold Block Model – Section 8650E 185 Figure 17-12 Typical Section of the Vein Zone Silver Block Model – Section 8650E 186 Figure 17-13 : Final Pit Design 196 Figure 17-14: Vein Zone - Dilution and Ore Losses 197 Figure 23-1: El Retiro Equipotential Map 217 Figure 23-2: Eureka Equipotential Map 218 Figure 23-3: El Retiro Proposal Wells 220 Figure 23-4: Eureka Longitudinal Section 222 Figure 23-5: Eureka Isometric View 223 Figure 23-6: General Mining Sequence 224 Figure 23-7: Eureka Stopes Dimensions 226 Figure 23-8: Bajo Negro Isometric View 227 Figure 23-9: Final Pit Design 228 1892-RPT-010 viii Rev: 0 Date: July 2010 9999FM0105 – 1 Figure 23-10: Eureka Mining Sequence 229 Figure 23-11: Bajo Negro Mining Sequence 229 Figure 23-12: Vein Zone Initial Pushback 230 Figure 23-13: Eureka Main Decline Layout 238 Figure 23-14: Ventilation Flow Direction 238 Figure 23-15: Bajo Negro Infrastructure Layout 239 Figure 23-16: Eureka Material Storage Areas 242 Figure 23-17: Bajo Negro Material Storage Areas 242 Figure 23-18: Vein Zone Waste Dump 243 Figure 23-19: Refuge and Escape Shaft 244 Figure 23-20: Refuge and Escape Shaft Details 244 Figure 23-21: Power Supply and Distribution 245 Figure 23-22: Process Plant Overall Process Flow Diagram 251 Figure 23-23: Process Plant General Arrangement 252 Figure 23-24: Route of 132 kV Transmission Line 265 Figure 23-25: Site Access Roads 268 Figure 23-26: Tailings Storage Facility General Arrangement 280 Figure 23-27: Assumed Model for the Stability Analyses 282 Figure 23-28: Typical Dam Section 283 Figure 23-29: Water Balance Flow Diagram 285 Figure 23-30: Tailings Storage Facility Development Sequence 286 Figure 23-31: Growth Curve of Dam 1 287 Figure 23-32: Growth Curve of Dam 2 288 Figure 23-33: Eureka General Plan and Drill Hole Locations 299 Figure 23-34: Bajo Negro Drill Hole Locations 300 Figure 23-35: Vein Zone General Plan and Drill Hole Locations 301 Figure 23-36: Schematic sketch showing definition of stope nomenclature 304 Figure 23-37: Definition of Bajo Negro Geotechnical Domains on Base of Downhole Intersections 307 Figure 23-38: Summary of surface geology, Vein Zone pit 313 Figure 23-39: RMR 76' per Vein Zone domain 316 Figure 23-40: Design Cross-sections Considered in Vein Zone Pit 318 Figure 23-41: Vein Zone Design Sections A and B 319 Figure 23-42: Geometric Definitions of Open Pit Slopes 320 Figure 23-43: Senior Management 341 Figure 23-44: Gold – London PM Fix 2000 – Present 347 Figure 23-45: Silver – London PM Fix 2000 – Present 347 Figure 23-46: Gold Annual Total Demand 348 Figure 23-47: Gold Annual Total Supply 348 Figure 23-48: Sensitivity Analysis 354 Figure 23-49: Project Organization 355 1892-RPT-010 ix Rev: 0 Date: July 2010 9999FM0105 – 1
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