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Form 6-K IAMGOLD CORP For: Nov 05

November 5, 2018 2:05 PM EST

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FORM 6-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Report of Foreign Private Issuer

Pursuant to Rule 13a-16 or 15d-16
of the Securities Exchange Act of 1934

Date: November 5, 2018
Commission File Number 001-31528

IAMGOLD Corporation
(Translation of registrant's name into English)

401 Bay Street Suite 3200, PO Box 153
Toronto, Ontario, Canada M5H 2Y4
Tel: (416) 360-4710
(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

  Form 20- F      [  ] Form 40-F      [X]  

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ____

Note: Regulation S-T Rule 101(b)(1) only permits the submission in paper of a Form 6-K if submitted solely to provide an attached annual report to security holders.

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ____

Note: Regulation S-T Rule 101(b)(7) only permits the submission in paper of a Form 6-K if submitted to furnish a report or other document that the registrant foreign private issuer must furnish and make public under the laws of the jurisdiction in which the registrant is incorporated, domiciled or legally organized (the registrant’s “home country”), or under the rules of the home country exchange on which the registrant’s securities are traded, as long as the report or other document is not a press release, is not required to be and has not been distributed to the registrant’s security holders, and, if discussing a material event, has already been the subject of a Form 6-K submission or other Commission filing on EDGAR.

Indicate by check mark whether by furnishing the information contained in this Form, the registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes      [  ]      No      [X]

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82-_


Description of Exhibit

Exhibit Description of Exhibit
   
99.1 NI 43-101 Technical Report on the Rosebel Gold Mine, Brokopondo District, Suriname (effective September 23, 2018) dated November 5, 2018

-2-


Signatures

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

  IAMGOLD CORPORATION
     
     
Date: November 5, 2018 By: /s/ Tim Bradburn
    Vice President, Legal and Corporate Secretary

-3-



IAMGOLD CORPORATION
 

TECHNICAL REPORT ON THE
ROSEBEL GOLD MINE, SURINAME

NI 43-101 Report

Qualified Persons:
Michel Payeur, Eng., M.A.Sc.
Raphaël Dutaut, P.Geo.
Adam Doucette, P.Eng.
Stéphane Rivard, P.Eng.
Dominic Chartier, P.Geo.
Oy Leuangthong, PhD, P.Eng.

November 5, 2018
Effective Date: September 23, 2018
 
IAMGOLD Corporation 401 Bay Street, Suite 3200, Toronto, Ontario M5H 2Y4 I T +1 416-360-4710 I www.iamgold.com



TABLE OF CONTENTS

      PAGE
       
1 SUMMARY 1-1
  1.1 Executive Summary 1-1
  1.2 Technical Summary 1-6
       
2 INTRODUCTION 2-1
  2.1 Sources of Information 2-1
  2.2 Effective Dates 2-3
  2.3 List of Abbreviations 2-4
       
3 RELIANCE ON OTHER EXPERTS 3-1
     
4 PROPERTY DESCRIPTION AND LOCATION 4-1
  4.1 RGM Property 4-1
  4.2 Saramacca Property 4-7
  4.3 Discussion 4-11
       
5 ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY 5-1
  5.1 Topography, Elevation, and Vegetation 5-1
  5.2 Accessibility 5-1
  5.3 Climate and Length of Operating Season 5-2
  5.4 Surface Area and Physical Resources 5-3
       
6 HISTORY 6-1
  6.1 RGM - Ownership, Exploration, and Development History 6-1
  6.2 Saramacca – Ownership, Exploration, and Development History 6-6
       
7 GEOLOGICAL SETTING AND MINERALIZATION 7-1
  7.1 Regional Geology 7-1
  7.2 RGM Concession 7-3
  7.3 Saramacca Concession 7-7
       
8 DEPOSIT TYPES 8-1
     
9 EXPLORATION 9-1
  9.1 RGM Concession, Exploration Program 2017-2018 9-1
  9.2 Saramacca Concession 9-3
  9.3 Regional Exploration 9-6
       
10 DRILLING 10- 1
  10.1 Introduction 10- 1
  10.2 Saramacca Concession Drilling 10-5
     
11 SAMPLE PREPARATION, ANALYSES AND SECURITY 11-1
  11.1 RGM Concession 11-1
  11.2 Saramacca Concession 11-6
     
12 DATA VERIFICATION 12-1

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Technical Report NI 43- 101 – November 5, 2018 Page i




  12.1 RGM Concession Data Verification 12-1
  12.2 Saramacca Concession Data Verification 12-2
       
13 MINERAL PROCESSING AND METALLURGICAL TESTING 13-1
  13.1 RGM Metallurgical Testing 13-1
  13.2 Saramacca Metallurgical Testing 13-15
       
14 MINERAL RESOURCE ESTIMATE 14-1
  14.1 Summary 14-1
  14.2 RGM Concession 14-2
  14.3 Saramacca Concession 14-22
       
15 MINERAL RESERVE ESTIMATES 15-1
  15.1 Summary 15-1
  15.2 Resource Models 15-2
  15.3 Dilution 15-2
  15.4 Mining Losses 15-3
  15.5 Mine Optimization Methodology 15-3
  15.6 Cut-Off Grade 15-4
  15.7 Pit Slope Designs 15-7
  15.8 Mine Plan 15-10
  15.9 Design Summary 15-25
  15.10 Stockpiles 15-26
  15.11 Mineral Reserves 15-26
       
16 MINING METHODS 16-1
  16.1 Saramacca Mining Fleet 16-1
  16.2 RGM Mining Fleet 16-1
  16.3 Production Drilling 16-2
  16.4 Mine Operations 16-3
  16.5 Life of Mine Production Schedule 16-8
       
17 RECOVERY METHODS 17-1
  17.1 Overview of the Existing Processing Plant 17-2
  17.2 Conclusion 17-7
  17.3 Integration of Saramacca into the Existing Processing Plant 17-8
       
18 PROJECT INFRASTRUCTURE 18-1
  18.1 RGM Site 18-1
  18.2 Saramacca Site 18-10
  18.3 Tailings Storage Facility 18-11
       
19 MARKET STUDIES AND CONTRACTS 19-1
  19.1 Markets 19-1
  19.2 Contracts 19-1
       
20 ENVIRONMENTAL STUDIES, PERMITTING, AND SOCIAL OR COMMUNITY IMPACT   20-1
  20.1 Current Status 20-1
  20.2 Future Permitting 20-2

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Technical Report NI 43- 101 – November 5, 2018 Page ii




  20.3 Environmental and Socio-Economic Studies 20-4
  20.4 Social Environment 20-5
  20.5 Management Plans and Controls 20-8
  20.6 Waste and Tailings Disposal, Site Monitoring, and Water Management 20-11
  20.7 Mine Closure and Reclamation Plan 20-13
       
21 CAPITAL AND OPERATING COSTS 21-1
  21.1 Capital Costs 21-1
  21.2 Operating Costs 21-6
       
22 ECONOMIC ANALYSIS 22-1
     
23 ADJACENT PROPERTIES 23-1
     
24 OTHER RELEVANT DATA AND INFORMATION 24-1
     
25 INTERPRETATION AND CONCLUSIONS 25-1
     
26 RECOMMENDATIONS 26-1
     
27 REFERENCES 27-1
     
28 DATE AND SIGNATURE PAGE 28-1
     
29 CERTIFICATE OF QUALIFIED PERSON 29-1
     
APPENDIX A A-1
   
APPENDIX  B B-1
   
APPENDIX C C-1

LIST OF TABLES

    PAGE
     
Table 1-1 Consolidated Mineral Resource Statement - Rosebel Gold Mine, Including Saramacca Gold Deposit 1-2
Table 1-2 Consolidated Mineral Reserve Statement – Rosebel Gold Mine, Including Saramacca Gold Deposit 1-3
Table 1-3 Exploration Activities on the Rosebel Concession - Past Three Years 1-11
Table 1-4 Exploration Activities on the Saramacca Concession Since 2002 1-11
Table 6-1 Past Production 6-5
Table 6-2 Previous Mineral Resource Statement for Saramacca Property, SRK Consulting (Canada) Inc., Effective August 28, 2017 6-8
Table 9-1 Summary of Exploration Work Completed on the RGM Concession 9-2
Table 9-2 Summary of Exploration Work Completed by Golden Star and Newmont at the Saramacca Gold Project 9-3
Table 9-3 Main Exploration Activity Statistics per Period of Activity 9-14
Table 9-4 Statistics of Brokolonko Concession Exploration Activity by IAMGOLD-RGM . 9-15  
Table 9-5 Statistics of Exploration Activity by IAMGOLD-RGM on the Saramacca Concession Outside of the Saramacca Development Area 9-16
Table 10-1  2004 – 2018 RGM Diamond Drilling and Reverse Circulation Drilling 10-1
Table 10-2 Statistics of Drilling Conducted on the Saramacca Gold Project to May 2018  10-5 

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Technical Report NI 43- 101 – November 5, 2018 Page iii




Table 10-3 Summary of Drilling Performed by IAMGOLD-RGM between July 2017 and May 2018 10-8
Table 11-1 Pulverize and Leach Standard Reference Material Summary 2017 11-5
Table 11-2 Standard Procedure for Quality Control Sample Insertion Rates, Saramacca Project 11-9
Table 11-3 Summary of Certified Reference Materials used by IAMGOLD-RGM from July 2017 to April 2018 11-10
Table 12-1 Summary of Analytical Quality Control Data Produced By IAMGOLD-RGM on the Saramacca Gold Project (July 2017 – April 2018) 12-5
Table 13-1 Optimization Metallurgical Test Work Performed 13-2
Table 13-2 Average Mineral Abundance by Rock Type 13-5
Table 13-3 Overall Grindability Statistics 13-7
Table 13-4 Average Grindability Results per Rock Type 13-8
Table 13-5 Axb and Bond Work Index Per Pit in Function of the Type of Ore 13-8
Table 13-6 Cyanidation Test Results (Whole Ore Leach)* 13-12
Table 13-7 Cyanide Consumption Data 13-13
Table 13-8 Assumed Recoveries Per Rock Type and Pit 13-14
Table 13-9 Scoping Study Recoveries per Rock Type 13-15
Table 13-10 Metallurgical Test Plan 13-17
Table 13-11 CM Head Assays 13-19
Table 13-12 VT Head Assays 13-20
Table 13-13 Composites Head Assays 13-21
Table 13-14 Composite Tails MineraLogy 13-21
Table 13-15 Summary of SMC and Bond Comminution Test Results 13-25
Table 13-16 Summary of Comminution Test Results for Composites Samples 13-25
Table 13-17 Comparison of Saramacca and Rosebel Comminution Data for Fresh Rock 13-27  
Table 13-18 Gravity Test Results 13-28
Table 13-19 Bulk Gravity Test Results 13-28
Table 13-20 Leaching Test Conditions 13-29
Table 13-21 Whole Ore Leach Average Test Results 13-29
Table 13-22 Size by Size Analysis of Gold in Cyanidation Tails of Whole Ore Leach 13-31
Table 13-23 Gold Recovery in Fine Ground Ores 13-32
Table 13-24 Comparison of COREM and SGS Lakefield Leach Results 13-33
Table 13-25 Gold Recovery in STR Leaching and Bottle Roll Comparison 13-34
Table 13-26 Flotation Flowsheet Summary 13-35
Table 13-27 Overall Recovery by Rock Type for Saramacca 13-36
Table 13-28 Comparison of Main Design Criteria for Saramacca vs RGM 13-39
Table 14-1 Consolidated Mineral Resource Statement - Rosebel Gold Mine, Including Saramacca Gold Deposit 14-1
Table 14-2 Drill Hole Data Collection Used for Resources Estimation 14-3
Table 14-3 RGM Resources – Bulk Density Data 14-6
Table 14-4 Grade Control Reverse Circulation Drilling - Assays Statistics 14-7
Table 14-5 Diamond Drill Hole and exploration Reverse Circulation Drilling - Assay Statistics 14-8
Table 14-6 Block Models Properties 14-9
Table 14-7 Detailed Block Model Parameters. 14-10
Table 14-8 Estimation Parameters Used during Interpolation 14-12
Table 14-9 RGM Measured, Indicated, and Inferred MIneral Resource Estimation as of September 1, 2018 14-18
Table 14-10 RGM Previous Mineral Resource Estimates 14-22

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Technical Report NI 43- 101 – November 5, 2018 Page iv




Table 14-11 Drilling Database for Saramacca Gold Project 14-25
Table 14-12 Mineral Resource Domains with Rock Codes 14-31
Table 14-13 Assay Statistics for Saramacca Gold Project 14-33
Table 14-14 Uncapped and Capped Composite Statistics 14-34
Table 14-15 Cap Values for Specific Gravity 14-36
Table 14-16 Gold Variograms by Domain 14-36
Table 14-17 Saramacca Gold Project GEMS Block Model Definition 14-37
Table 14-18 Estimation Parameters for Gold and Specific Gravity (last row) 14-40
Table 14-19 Classified Mineral Resources by Weathering Zone*, Saramacca Gold Project, SRK Consulting (Canada) Inc., September 13, 2018 14-47
Table 14-20 Global Block Model Quantity and Grade Estimates* at Various Cut-off Grades 14-48
Table 14-21 Mineral Resource Statement*, Saramacca Gold Project, Suriname, SRK Consulting (Canada) Inc., August 28, 2017 14-51
Table 14-22 Comparison between 2017 and 2018 Mineral Resource Statements 14-51
Table 15-1 Consolidated Mineral Reserve Statement – Rosebel Gold Mine, Including Saramacca Gold Deposit 15-1
Table 15-2 Resource Block models 15-2
Table 15-3 Pit Optimization Cost and Revenue Assumptions 15-5
Table 15-4 Summary of 2018 Pit Optimization COGs at US$1,200/oz 15-5
Table 15-5 Summary of Pit Optimization Parameters 15-6
Table 15-6 Pit Design Slope Recommendations per Rock Type 15-9
Table 15-7 Stockpile Status as of September 1, 2018 15-26
Table 15-8 RGM Proven and Probable Mineral Reserves 15-27
Table 16-1 Maximum Estimated Life of Mine Primary Mine Equipment Fleet 16-2
Table 16-2 Reverse Circulation Grade Control Parameters 16-5
Table 16-3 Drill and Blast Parameters 16-7
Table 16-4 Weighting Factors per deposit 16-8
Table 16-5 Life of Mine Plan 16-11
Table 17-1 Mill Consumables 17-7
Table 18-1 Projected Life of Mine Power Demand 18-9
Table 20-1 Saramacca Completed ESIA Environmental and Socio-Economic Studies 20-5
Table 20-2 Waste Rock by Pit 20-12
Table 20-3 Rosebel Closed Site Summary Description 20-15
Table 21-1 Major Equipment Purchase Replacement Schedule 21-5

LIST OF FIGURES

    PAGE
     
Figure 4-1 Location Map 4-2
Figure 4-2 RGM Concession and Exploration Concessions 4-3
Figure 7-1 Guiana Shield – Simplified Geological Map 7-2
Figure 7-2 RGM Concession and Charmagne Exploration Concession – Geological Map 7-5  
Figure 7-3 Rosebel Property – N-S Geological Cross Section 7-6
Figure 7-4 Example of Typical Brittle Features, Faya Bergi Fault 7-9
Figure 7-5 Example of Typical Ductile Features, Faya Bergi Fault (SRK, 2017a) 7-10
Figure 9-1 Location of Historical Exploration Work Conducted by Golden Star and Golden Star/Newmont  9-4

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Technical Report NI 43- 101 – November 5, 2018 Page v




Figure 9-2 RGM Mine Concession and Adjacent Exploration Properties 9-7
Figure 10-1 Location of all Drilling Performed on the Saramacca Gold Project 10-6
Figure 10-2 Reverse Circulation Drilling Sample Flowchart 10-15
Figure 13-1 Main Expansion Initiatives Since 2004 13-3
Figure 13-2 Average Mineral Abundance by Rock Type 13-6
Figure 13-3 CEET™ Forecast 13-10
Figure 13-4 Average Gravity Gold Recovery by Deposit Using Mozley Table 13-11
Figure 13-5 Overall Average Gold Recovery by Rock Type 13-12
Figure 13-6 Overall Average Recovery by Pit 13-13
Figure 13-7 Spatial Localization of the Variability Samples 13-18
Figure 13-8 Spatial Localization of the Composites 13-19
Figure 13-9 Gold Associations in Concentrates by Rock Type 13-23
Figure 13-10 Gold Grain Size for Saprolite 13-24
Figure 13-11 Gold Grain Size for Transition and Fresh Rock 13-24
Figure 13-12 SPI Results for Saramacca and Rosebel 13-26
Figure 13-13 Gold Recovery With and Without Carbon for the Composites 13-33
Figure 13-14 TSS in Function of Flocculant Dosage 13-37
Figure 13-15 Average NaCN Consumption by Saramacca Rock Types 13-38
Figure 13-16 Average CaO Consumption of Saramacca Rock Types vs RGM Rock Types 13-38
Figure 14-1 Isometric View – Northern Deposits Ore Zones 14-5
Figure 14-2 DDH Variogram Models Used for Model 4 14-14
Figure 14-3 Swath Plots for Royal Hill Block Model 14-16
Figure 14-4 Percentage Change in Ounces for the Range of Gold Prices Between US$1,000 and US$2,000/oz Compared to the US$1,500/oz Au Price 14-21
Figure 14-5 Plan and Long Section Showing the Modelled Saramacca Gold Project Lithological and Grade Domains 14-27
Figure 14- 6 Vertical Section 1700NW Showing Modelled Saramacca Gold Project Lithology and Grade Domains in Relation to Drilling 14-28
Figure 14- 7 Vertical Section 1100NW Showing Modelled Saramacca Gold Project Lithology and Grade Domains in Relation to Drilling 14-29
Figure 14- 8 Vertical Section 575NW Showing Modelled Saramacca Gold Project Lithology and Grade Domains in Relation to Drilling 14-30
Figure 14- 9 Boxplot of Specific Gravity by Weathering Zone 14-32
Figure 14- 10 Assay Lengths for Combined Historical and IAMGOLD Data 14-33
Figure 14- 11 Grade Probability Plot (Left) and Capping Sensitivity Curve (Right) for Fault LG Domain 14-35
Figure 14- 12 Gold Variogram for Fault Low Grade Zone 14-37
Figure 14- 13 Contact Plots Between Low- and High-Grade Zones in the Fault Zone (left) and Pillow Basalt (right) 14-41
Figure 14- 14 Swath Plot of Block Models, Oriented Along Strike 14-42
Figure 14-15 Comparison of Quantile- Quantile Plot for Block Model Grades and Declustered and Change of Support Corrected Distribution (left) and Grade Tonnage Curves (right) for Fault Low Grade (top row) and Fault High Grade (bottom row) 14-43
Figure 14-16 Distribution of Average Distance of Informing Composites for Indicated Blocks 14-44
Figure 14-17 Plan Showing Estimated Blocks Above 0.25 g/t Gold Relative to the Conceptual Pit 14-46
Figure 14-18 Global Grade- Tonnage Curves – Oxide (top) Transitional (mid) and Fresh Material (bottom) 14-49
Figure 15-1 Pay Caro Ultimate Pit 15-11

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Technical Report NI 43- 101 – November 5, 2018 Page vi




Figure 15-2 Pay Caro Waste Dumps 15-12
Figure 15-3 J Zone Ultimate Pit 15-13
Figure 15-4 J Zone Dump 15-14
Figure 15-5 Koolhoven Ultimate pit 15-15
Figure 15-6 Koolhoven Dump 15-16
Figure 15-7 Royal Hill Ultimate Pit 15-17
Figure 15-8 Royal Hill Waste Dumps 15-18
Figure 15-9 Mayo Ultimate Pit 15-19
Figure 15-10 Mayo Pit Waste Dumps 15-20
Figure 15-11 Rosebel Ultimate Pit 15-21
Figure 15-12 Rosebel Pit Waste Dump 15-22
Figure 15-13 Roma Pit Phase RMW 15-23
Figure 15- 14 Saramacca Ultimate Pit 15-25
Figure 16- 1 Saramacca to Maya Haul Road and Proximity to the RGM Operations 16-4
Figure 16- 2 Mining by Pit – RGM and Saramacca 2019 Life of Mine Plan 16-9
Figure 16- 3 Mill Feed – RGM and Saramacca 2019 Life of Mine Plan 16-10
Figure 17- 1 Ore Processed and Hard Rock Ratio 17-2
Figure 17- 2 RGM Process Flowsheet 17-3
Figure 18- 1 Processing Plant Area 18-3
Figure 18- 2 Potable Water Plant Facility 18-5
Figure 18- 3 Fire Protection Pump Facility 18-6
Figure 18- 4 Rosebel 5 MW Solar Power Plant 18-8
Figure 18- 5 Tailings Storage Facility 18-13
Figure 20- 1 ESIA Process Flowsheet 20-3
Figure 21- 1 Life of Mine Expenditure 21-2
Figure 21- 2 Capitalized Waste Stripping 21-4

IAMGOLD Corporation - Rosebel Gold Mine  
Technical Report NI 43- 101 – November 5, 2018 Page vii




1

SUMMARY


1.1

EXECUTIVE SUMMARY

This Technical Report was prepared by Rosebel Gold Mines N.V. (RGM), IAMGOLD Corporation’s (IAMGOLD) subsidiary for the Rosebel Gold Mine, located in Suriname, and SRK Consulting (Canada) Inc. (SRK) to support the disclosure of the current Mineral Resource and Mineral Reserve estimates for the Rosebel Gold Mine, including the Saramacca property located approximately 25 km southwest of the Rosebel processing plant. This Technical Report conforms to National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101).

IAMGOLD is a mid-tier mining company with four operating gold mines and several exploration properties on three continents. IAMGOLD, through its wholly-owned subsidiary RGM, owns 95% of the RGM concession in Suriname, with the Government of Suriname holding the remaining 5%. The mine has been operating commercially since February 2004.

The Saramacca property, included in the disclosed Mineral Resource and Mineral Reserve estimate, is owned under a joint venture agreement in which RGM holds a 70% interest and the Republic of Suriname holds the remaining 30% interest. Commercial production at the Saramacca property is currently scheduled for the second half of 2019.

Table 1-1 summarizes the consolidated Mineral Resource estimates for the Rosebel Gold Mine, inclusive of the Saramacca deposit. The effective dates of the estimates are September 1, 2018 for the Rosebel Gold Mine and September 13, 2018 for Saramacca property. Mineral Resources and Mineral Reserves have been prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral Resources and Mineral Reserves dated May 10, 2014 (CIM definitions).

IAMGOLD Corporation - Rosebel Gold Mine  
Technical Report NI 43- 101 – November 5, 2018 Page 1-1



TABLE 1-1     CONSOLIDATED MINERAL RESOURCE STATEMENT -
ROSEBEL GOLD MINE, INCLUDING SARAMACCA GOLD DEPOSIT

Deposit Classification Tonnes
(000)
Grade
(g/t Au)
Contained
Ounces (000)
100% Basis
Attributable
Contained
Ounces (000)
  Measured 34,216 0.6 696 661
RGM Indicated 261,108 0.9 7,817 7,426
  Measured & Indicated 295,324 0.9 8,513 8,087
  Inferred 65,154 0.9 1,797 1,707
  Indicated 27,938 2.0 1,763 1,172
Saramacca Inferred 11,824 0.7 273 182
  Measured 34,216 0.6 696 661
  Indicated 289,047 1.0 9,580 8,598
Consolidated Measured & Indicated 323,262 1.0 10,276 9,260
  Inferred 76,978 0.8 2,070 1,889

Notes:

  1.

Attributable ounces: 95% for Rosebel (excluding Saramacca), 66.5% for Saramacca.

  2.

CIM definitions were followed for classification of Mineral Resources.

  3.

Mineral Resources reported at a weighted average cut-off grade for Rosebel (excluding Saramacca) of 0.18 g/t Au for saprolite, 0.23 g/t Au for transition material and 0.35 g/t Au for fresh rock material. Average cut-off grades for Saramacca are 0.25 g/t Au for laterite and saprolite, 0.30 g/t Au for transition material and 0.50 g/t Au for fresh rock material.

  4.

Mineral Resources for RGM include 2018 depletion prior to September 1, 2018.

  5.

Mineral Resources are constrained within a pit shell estimated using a long-term gold price of US$1,500/oz.

  6.

Mineral Resources are inclusive of Mineral Reserves.

  7.

Numbers may not add due to rounding.

  8.

Effective date for Rosebel (excluding Saramacca) is September 1, 2018 . Effective date for Saramacca is September 13, 2018.

IAMGOLD and SRK are not aware of any environmental, permitting, legal, title, taxation, socioeconomic, marketing, political, or other relevant factors that could materially affect the Mineral Resource estimate.

Table 1-2 summarizes the consolidated Mineral Reserve estimate for the Rosebel Gold Mine inclusive of the Saramacca deposit.

IAMGOLD Corporation - Rosebel Gold Mine  
Technical Report NI 43- 101 – November 5, 2018 Page 1-2



TABLE 1-2     CONSOLIDATED MINERAL RESERVE STATEMENT – ROSEBEL
GOLD MINE, INCLUDING SARAMACCA GOLD DEPOSIT

Deposit Classification Tonnes
(000)
Grade
(g/t Au)
Contained
Ounces (000)
100% Basis
Attributable
Contained
Ounces (000)
RGM Proven & Probable 117,872 1.0 3,632 3,450
  Stockpiles 15,803 0.6 283 269
Saramacca Proven & Probable 26,549 1.8 1,542 1,025
Total   160,224 1.1 5,457 4,745

Notes:

  1.

Attributable ounces: 95% for Rosebel (excluding Saramacca), 66.5% for Saramacca.

  2.

CIM definitions were followed for Mineral Reserves .

  3.

Mineral Reserves are estimated assuming open pit mining methods.

  4.

Mineral Reserves are estimated using an average long-term gold price of US$1,200/oz.

  5.

Average weighted process recovery of 89.8%.

  6.

Mining cost: $2.19/t mined. Processing costs: $4.79/t milled. Power costs: $3.13/t milled. General and Administrative costs of $2.16/t milled.

  7.

Mineral Reserves include 2018 depletion prior to September 1, 2018.

  8.

Mineral Reserves include material from all pits, including Saramacca.

  9.

Bulk density is variable by rock type.

  10.

Numbers may not add due to rounding.

  11.

Effective date for Rosebel (excluding Saramacca) is September 1, 2018 . Effective date for Saramacca is September 13, 2018.

RGM is not aware of any mining, metallurgical, infrastructure, permitting, or other relevant factors that could materially affect the Mineral Reserve estimate.

The Mineral Resource and Mineral Reserve estimates have been completed to a level appropriate for feasibility studies, and are consistent with CIM definitions and are suitable for public reporting. As such, the Mineral Reserves are based on Measured and Indicated Mineral Resources, and do not include any Inferred Mineral Resources.

All currency is in US dollars unless noted otherwise.

1.1.1

CONCLUSIONS

IAMGOLD has the following conclusions and observations for the RGM Mineral Resource and Mineral Reserve update:

The Mineral Resource and Mineral Reserve estimates have been prepared in accordance with CIM definitions.
     
  Work completed to date by the geological staff is appropriate.

IAMGOLD Corporation - Rosebel Gold Mine  
Technical Report NI 43- 101 – November 5, 2018 Page 1-3




The geological model employed by RGM geologists is reasonably well understood and is well supported by field observations in both outcrop, pit mapping, and drill intersections.
     
The resource models have been prepared using appropriate methodology and assumptions. These parameters include:

  o Treatment of high assays;
  o Compositing length;
  o Search parameters;
  o Bulk density;
  o Cut-off grade;
  o Classification.

The block models have been validated using a reasonable level of rigour consistent with common industry practice.

   

The resource estimates reported herein are a reasonable representation of the Mineral Resources delineated at the Rosebel Gold Mine as of September 1, 2018.

   

The current drill spacing in all deposits is judged adequate to develop a reasonable model of the mineralization distribution and to quantify its volume and quality with a good level of confidence in all areas of the project.

   

Based on visual verification, the RGM models (Rock Type, Density, and Au Grade) were found to be globally representative of the known geological and structural controls of mineralization at the RGM deposit.

   

Statistical analysis demonstrates that the block model provides a reasonable estimate of the Mineral Resources of the RGM deposits.

   

Validation of the block models, using different interpolation methods, indicated that tonnages, grades, and gold contents are similar.

   

Block models at RGM were also compared and reconciled with production data and are considered as being appropriate.

   

Swath plots for Indicated and Inferred Mineral Resources, by vertical sections for the RGM pits, indicate that peaks and lows in gold content generally match peaks and lows in composite frequency; no bias was found in the resource estimate in this regard.

   

 

A review of the information stored in the RGM database found it to be in good standing.

   

Sampling and assaying have been carried out following standard industry quality assurance/quality control (QA/QC) practices. These practices include, but are not limited to, sampling, assaying, chain of custody of the samples, sample storage, use of third-party laboratories, standards, blanks, and duplicates.

   

The mine design and Mineral Reserve estimate have been completed to a level appropriate for an operating mine.


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The economic assumptions and methodology used for estimation of the Mineral Reserves are appropriate.

   

The Mineral Reserve estimate is consistent with CIM definitions and is suitable for public reporting. As such, the Mineral Reserves are based on Measured and Indicated Mineral Resources and do not include any Inferred Mineral Resources.

   

Current production statistics indicate that the process flow sheet is adequate and suitable for processing the Rosebel Gold Mine ore types.

SRK and IAMGOLD have the following conclusions and observations for the Saramacca Mineral Resource and Mineral Reserve update:

Mineral Resources and Mineral Reserves have been prepared in accordance with the CIM definitions.

   

 

Exploration data collected to date by IAMGOLD use procedures consistent with generally accepted industry best practices, and are sufficiently reliable to interpret with confidence the boundaries of the gold mineralization of the Saramacca gold deposit.

   

 

The geological model, constructed by SRK with the assistance of RGM geologists, is a reasonable representation of the gold mineralization at the current level of sampling.

   

 

The resource model has been prepared using appropriate methodology and assumptions:



  o Gold grades were estimated into a block model informed by composited gold assays, capped where appropriate, and using an ordinary kriging estimator.
  o Specific gravity was estimated into the blocks, using an inverse distance squared estimator, to convert volumes into tonnage.

The block model has been validated by both SRK and IAMGOLD using various methodologies, including statistical comparisons between composites and block model distributions, estimation using different estimation methods, and visual checks with informing composites. These validation steps demonstrate that the block model provides a reasonable estimate of the Mineral Resources of the Saramacca deposit.

   

 

The resource evaluations reported herein is a reasonable representation of the Mineral Resources delineated at the Saramacca deposit as of September 13, 2018.

   

 

The mine design and Mineral Reserve estimate have been completed to a level appropriate for an operating mine.

   

 

The economic assumptions and methodology used for estimation of the Mineral Reserves are appropriate.

   

 

The Mineral Reserve estimate is consistent with CIM definitions and is suitable for public reporting. As such, the Mineral Reserves are based on Measured and Indicated Mineral Resources and do not include any Inferred Mineral Resources.


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Current production statistics indicate that the process flow sheet is adequate and suitable for processing the Saramacca deposit ore types.

1.1.2

RECOMMENDATIONS

IAMGOLD and SRK have the following recommendations:

Continue the process of updating the resource models to incorporate the remaining deposits and update of the geological models of the current orebodies.
     
  Continue upgrading the Inferred Mineral Resources to Indicated Mineral Resources.
     
Implement a stringent planning and operations process for following the variable cut- off grades in production, and closely monitor the reconciliation between planning and production.
     
Further refine the mine cost model for future input to the long term planning and scheduling designs.
     
Complete geological studies to build on existing knowledge and improve the understanding of the geological and structural setting of the Rosebel Gold Mine and Saramacca deposits. This may include further infill drilling to improve classification.
     
Test the lateral and depth extent of the Rosebel Gold Mine and Saramacca gold mineralization to potentially expand the Mineral Resources.
     
Continue optimization of the development of the Saramacca project, notably relevant to increasing metallurgical recovery, achieving pit slope dewatering to improve overall slope angles in saprolite, and optimized waste dump designs to reduce berm construction requirements.
     
  Investigate underground development potential for the Saramacca deposit.

1.2

TECHNICAL SUMMARY


1.2.1

PROPERTY DESCRIPTION AND LOCATION

The Rosebel property is located in Suriname, South America, approximately 80 km south of the city of Paramaribo, the capital of Suriname. Suriname is a former Dutch colony located on the northeastern coast of South America.

1.2.2

LAND TENURE

The Rosebel Gold Mine area consists of the following RGM concessions: Gross Rosebel concession (or the RGM concession), which contains the Royal Hill, Mayo, Roma, Rosebel, Koolhoven, Pay Caro, East Pay Caro, and J Zone deposits, seven exploration concessions (Headley’s Reef, Charmagne 1, Charmagne 2, Charmagne West, Thunder Mountain, Anjoemara en Lef Resources, and Brokolonko, all located on contiguous ground), and the Saramacca exploration concession. The Saramacca concession is located approximately 25 km southwest of the Rosebel Gold Mine milling facility.

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All these concessions are owned by RGM, which is a Surinamese company created for the purpose of exploring for and developing all minerals including gold, precious metals, base metals and stones and operating the Rosebel Gold Mine. IAMGOLD owns a 95% interest in RGM, while the Republic of Suriname has a 5% free-carried interest. The Saramacca concession is owned under a joint venture agreement between RGM holding 70% and the Republic of Suriname holding the remaining 30% interest.

1.2.3

HISTORY


1.2.3.1

RGM CONCESSION

Golden Star Resources Ltd. (Golden Star) was granted the Right of Exploration (ROE) for the Rosebel property for five years in 1994, pursuant to a Mineral Agreement signed between Golden Star, NV Grassalco (Grassalco), and the Government of Suriname on April 7, 1994. Golden Star entered into an agreement with Cambior Inc. (Cambior) on June 7, 1994, granting Cambior the option to earn an undivided 50% of Golden Star’s interest in the 1994 Mineral Agreement and the Rosebel property.

On October 26, 2001, Golden Star sold its 50% interest in the Rosebel property to Cambior for a cash consideration of $8 million and a gold price participation right on future production from Rosebel. Under its gold price participation right, Golden Star would receive a quarterly payment of an amount equal to 10% of the excess, if any, of the average quarterly market price above US$300/oz for gold production from RGM’s soft and transitional rock portions and above US$350/oz from RGM’s hard rock portion, up to a maximum of seven million ounces produced.

Commercial production at Rosebel Gold Mine began in February 2004. In 2004, Golden Star sold the royalty interest in production at the Rosebel property to Euro Resources SA (Euro Resources - formerly Guyanor Resources SA). In November 2006, IAMGOLD acquired a 100% interest in Cambior (the previous owner of RGM), thereby acquiring 95% of RGM. In December 2008, IAMGOLD acquired 84.55% of the current share capital of Euro Resources.

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In June 2013, IAMGOLD, RGM, Grasshopper Aluminum Company N.V., and the Republic of Suriname executed the Second Amendment to the Mineral Agreement. The Second Amendment created a new Unincorporated Joint Venture vehicle (UJV) in which the Republic of Suriname would hold, through NV1, a wholly owned subsidiary of the Republic, a paid 30% interest and RGM would hold a 70% interest. Under the terms of the Second Amendment, NV1 has been granted an option to acquire an increased interest in production from the RGM concession if RGM approves a Significant Expansion of the existing mill and if NV1 elects to participate in the Significant Expansion by funding 30% of the capital required for the expansion.

In December 2015, IAMGOLD announced the closing of a simplified tender offer for Euro Resources through the Euronext Paris Stock Exchange (Euronext Paris), thereby owning approximately 90% of the outstanding common shares of Euro Resources.

1.2.3.2

SARAMACCA CONCESSION

The first recorded exploration on the Saramacca gold project was undertaken by Golden Star in 1994. During this time, the Saramacca concession was part of a larger grants package known as Kleine Saramacca.

In August 2006, Golden Star signed a joint venture with Newmont Mining Corporation (Newmont), whereby Golden Star would remain the operator of the Saramacca gold project. In 2007 and 2008 Newmont funded all exploration activities at Saramacca, with Golden Star personnel managing the project. During 2009, Newmont earned a 51% interest in the Saramacca gold project by spending $6.0 million on exploration expenditures, and took over management of the programs.

In November 2009, Golden Star entered into an agreement to sell its interest in the Saramacca joint venture to Newmont for approximately $8.0 million. In December 2012, all requirements for the sale and transfer were met, and ownership and control of the Saramacca gold project was turned over to Newmont for total consideration of $9.0 million in cash.

In 2013, the Saramacca gold property was returned to the Republic of Suriname.

RGM signed a Letter of Agreement with the Republic of Suriname on August 30, 2016, to acquire the rights to the Saramacca gold property. The terms of the Letter of Agreement included an initial payment of $200,000 which enabled immediate access to the property for IAMGOLD-RGM’s exploration team to conduct due diligence, as well as access to historical data from previous exploration activity at the Saramacca property.

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On September 29, 2016, IAMGOLD ratified the Letter of Agreement by Ratification Letter and amended the Letter of Agreement on December 12, 2016 to acquire the Saramacca property. IAMGOLD subsequently paid $10 million in cash and agreed to issue 3.125 million IAMGOLD common shares to the Republic of Suriname in three approximately equal annual instalments on each successive anniversary of the date the right of exploration was transferred to RGM.

1.2.4

GEOLOGY AND MINERALIZATION

The RGM concession lies within a greenstone belt of the Paleoproterozoic Guiana Shield which stretches from the Amazon River in Brazil to the Orinoco River in Venezuela and covers an area of more than 900,000 km2. In Suriname, sedimentary and volcanic units of the greenstone belt are grouped into the Marowijne Supergroup which is divided itself into two formations: the Paramaka Formation constituted of volcanic rocks, and the Armina Formation constituted of flysch sequences represented by greywacke, mudstone, and conglomerate.

1.2.4.1

RGM CONCESSION

The Rosebel deposits are hosted by a volcano-sedimentary sequence of the Marowijne Supergroup and by the overlying detrital sedimentary sequence of the Rosebel Formation. Five types of rocks are distinguished on the property: felsic to mafic volcanic rocks, flysch sequence, arenitic sedimentary rocks, felsic intrusion, and late diabase dykes. Economical gold mineralization has been recognized in sedimentary and volcanic rocks while the intrusion only shows rare gold occurrences and the late diabase dykes are devoid of any mineralization.

Two phases of deformation are recognized on the property. The first one has affected the older volcanic rocks only, while the second phase of deformation has affected the volcanic rocks and both sedimentary sequences. The veins show no signs of deformation and so the mineralization is interpreted as being emplaced during the latest stage of the last deformation event.

Three mineralized domains are found on the property: the North, Central, and South domains. The northern domain includes the J Zone and Koolhoven deposits along a trend to the north of the volcanic rocks and the Pay Caro-East and Pay Caro deposits along a trend south of the volcanic rocks. The two trends follow a WNW-ESE orientation. The central domain only includes one deposit, Rosebel, which is striking east-west. The southern domain is also striking east-west and hosts the Mayo, Roma, and Royal Hill deposits.

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1.2.4.2

SARAMACCA CONCESSION

The Saramacca gold project is underlain by metabasalt of the Paramaka Formation. Younging from southwest to northeast, the main units of the Paramaka Formation are a massive basalt overlain by a thinner amygdular basalt unit and a thick unit of pillowed basalts. The massive basalt is a homogeneous, green, medium-grained unit in which leucoxene sporadically develops. The amygdular basalt unit is a greenish-grey to buff color where hydrothermally altered.

Located at the contact between the massive and pillowed basalts, the Faya Bergi fault zone is a major brittle-ductile vertical dip-slip fault zone with which gold mineralization is associated. Typical brittle features include cataclasite, gouge, fractured zones and striated fault slip planes, and typical ductile features include shear foliation and minor folding. Several sub-parallel minor shear zones occur on either side of the fault zone.

Mineralization at the Saramacca gold project is principally hosted within a series of north-northwest trending structures ranging between two metres and 40 m in width over a strike length of 2.2 km, and is open along strike. Several sub-parallel structures have been identified, however, the Faya Bergi and Brokolonko structures are the primarily mineralized structures over a continuous distance.

1.2.5

EXPLORATION STATUS


1.2.5.1

RGM CONCESSION

Table 1-3 provides a summary of exploration activities on the Rosebel concession over the past three years.

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TABLE 1-3     EXPLORATION ACTIVITIES ON THE ROSEBEL CONCESSION -
PAST THREE YEARS

2015

Intense detailed pit mapping in East Pay Caro, J Zone, Rosebel and Royal Hill to be used in further development of the pits, identifying optimal drilling directions for MinEx and RC grade control and new geological interpretation

   

Mapping and grab sampling of quartz veins in Mamakreek and Compagnie Creek

Small shallow auger program of 66 holes at Royal Hill SE pits of SSM tailings was conducted by MinEx

     

2016

Intense detailed pit mapping in East Pay Caro, West Pay Caro, J Zone, Rosebel, Royal Hill, Roma, Overman and Mayo to be used in further development of the pits, identifying optimal drilling directions for MinEx and RC grade control and update geological interpretation

     

2017

MineEx conducted pit mapping/grab sampling and pit testing in Koolhoven-J Zone, West Pay Caro, and Rosebella


1.2.5.2

SARAMACCA CONCESSION

Table 1-4 provides a summary of exploration drilling at Saramacca since 2002. From 2016 to 2018, exploration work conducted by IAMGOLD on the Saramacca concession was performed by the Suriname Exploration department (SurEx) focused on exploration work conducted outside of the RGM concession. Exploration activities in the first and second quarter of 2018 were performed by the Mine Exploration department (MinEx).

TABLE 1-4     EXPLORATION ACTIVITIES ON THE SARAMACCA CONCESSION
SINCE 2002

  Goldstar Goldstar/Newmont  Goldstar/Newmont IAMGOLD-RGM  Total
Hole Type 2002-2005 2006-2008  2009-2010 SurEx 2016- 2018 MinEx 2018  
  No. (m) No. (m) No. (m) No. (m) No. (m) No. (m)
Undefined 157 1,160 241 1,905 - - - - - - 398 3,065
                         
Diamond Drilling 24 1,307 30 3,566 36 4,420 286   60,701 66 15,472 442 85,466
                         
Reverse Circulation Drilling - - - - - - 41 4,986 - - 41 4,986

1.2.6

MINERAL RESOURCES


1.2.6.1

RGM CONCESSION

Excluding the Saramacca deposit, the Mineral Resource estimate at September 1, 2018 for the Rosebel Gold Mine is 295 million tonnes (Mt) at an average grade of 0.9 g/t Au, containing 8.513 Moz in the Measured and Indicated category. There is an additional 65 Mt at an average grade of 0.9 g/t Au, containing 1.789 Moz in the Inferred category.

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This Mineral Resource is estimated within pit shells optimized at a US$1,500/oz Au price and corresponding cut-off grades and includes the Measured, Indicated, and Inferred Mineral Resource categories. A volumetric analysis using GEMS is performed to determine the tonnage and grade of the Measured, Indicated, and Inferred Mineral Resources inside each of these shells. The stockpile inventory is classified as Measured and is included in the total.

1.2.6.2

SARAMACCA CONCESSION

The Mineral Resource estimate for the Saramacca gold project, at September 13, 2018, is 28 Mt at an average grade of 2.0 g/t Au, containing 1.763 Moz in the Indicated category, and 12 Mt at an average grade of 0.7 g/t Au for 0.273 Moz in the Inferred category. This estimate is based on open pit extraction, using a conceptual open pit shell developed by BBA Inc. (BBA) using the same optimization parameters as those used in the Mineral Reserve study. Mining, processing, and general and administrative (G&A) costs are based on a Mineral Reserve cost model, which was developed using an activity-based costing approach. Other pit optimization parameters include:

 

Overall slope angle 22° in laterite and saprolite, 36° in transition, and 45° in fresh rock.

Metallurgical gold recovery of 94.0% for laterite, 91.0% for saprolite, 89.6% for transition, and 74.8% for fresh rock.

 

Gold price of US$1,500 per troy ounce.

After review of optimization results, and through discussions with IAMGOLD, SRK considers that it is reasonable to report as Mineral Resource amenable to open pit extraction those classified blocks located within the conceptual pit shell above a cut-off grade of 0.25 g/t Au for laterite and saprolite, 0.30 g/t Au for transition material, and 0.50 g/t Au for fresh rock material.

1.2.7

MINERAL RESERVES

The Mineral Reserve estimate is based on updated resource models at year-end 2017 for all pits, with the exception of Saramacca which is based on an updated resource model from June 2018. All resource models were updated by RGM in GEMS format except for the Saramacca model which was prepared by SRK. All resource models were depleted to the September 1, 2018 surveyed surfaces.

The Mineral Reserve estimate only contains Measured and Indicated Mineral Resources within pit designs described in this document and is based on a pit optimization at $1,200/oz Au. Ore/waste allocation has been defined by the life of mine (LOM) schedule.

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The Mineral Reserve estimate is based on open pit mining methods and includes 160.2 Mt at an average grade of 1.1 g/t Au, containing 5.5 Moz in the Proven and Probable category on a 100% basis.

The Mineral Reserve has been determined based on the latest LOM plan. This was developed to maximize cash flow analysis based on an activity-based cost accounting, the theory of constraints as well as developing pit phasing and multi-pit scheduling. This strategy allowed IAMGOLD to maximize the net present value (NPV) of the operation while satisfying the operational constrains to achieve a sustainable mine operation and gold production profile.

The Mineral Reserve estimate includes a mining dilution of 8% for saprolite (soft) and 10% for transition and fresh rock (hard) ore. The percentage of dilution is a function of blasting which displaces the in-situ ore zones. As a result, soft ore that requires less blasting than transition or hard ore has a relatively lower dilution percentage. The dilution tonnes have been estimated at zero grade.

As described above, the dilution in relation to the ore type has been incorporated in the pit optimisation and mine planning process. The application of this dilution methodology effectively increases the mineralized tonnage by, for example 10% in transition and hard ore, with no change to final in-situ gold reserves thus reducing the gold head grade from the modelled in-situ to the diluted grade.

Historical Ore tonnage production has shown a consistent positive reconciliation at the Rosebel Gold Mine. As such, no mining losses are applied to the Mineral Reserve estimate resulting in a 100% mining recovery. The same methodology has been applied to the Mineral Reserve estimate at the Saramacca deposit.

1.2.8

MINING

The mining operation at Rosebel Gold Mine is a conventional truck and shovel, drill and blast, open pit operation, with an owner fleet.

In 2019, the annual ex-pit mining target is projected to be 67.3 Mt at stripping ratio of 5.49. The LOM plan for 2019 has 12.4 Mt processed at the Rosebel processing plant at an average grade 0.91 g/t Au to yield approximately 335 thousand ounces (koz) of recovered gold. This includes mining 0.99 Mt at Saramacca, at a stripping ratio of 3.43. During 2019, 0.22 Mt of Saramacca ore will be processed at the Rosebel processing plant at an average grade of 0.85 g/t Au for a total of 5.7 koz of recovered gold.

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A new primary mining fleet is planned for Saramacca and will consist of one Caterpillar (CAT) 6030 face shovel, two Komatsu PC2000 backhoes, and one PC1250 excavator with the support of one CAT 993 loader used at the run of mine (ROM) stockpile to load long-haul trucks. The proposed haulage fleet will consist of 20 CAT 785 haul trucks within the pit and 10 Haul-Max trucks to haul ROM from Saramacca to the Rosebel processing plant.

The RGM loading fleet consists of five CAT 6030 shovels and four CAT 5130 shovels using both the excavator and front shovel configuration supported by one CAT 993 loader used for ROM stockpile reclaim and one CAT 993 loader used in pit. The hauling fleet consists of 36 CAT 777 and 18 CAT 785 haul trucks. Dust control is accomplished with four CAT 777 and one CAT 769 water truck. RGM’s ancillary equipment includes, fuel trucks, mobile light plants, and service trucks.

The drilling fleet consists of a mixed fleet of 13 drills. Drill and blast parameters vary for each pit due to different material type and pit designs. All drill holes are 165 mm diameter. All blasting activities on site are executed by RGM employees. Holes are loaded with bulk explosive matrix and initiated with non-electric detonators.

Reverse circulation (RC) grade control drilling is planned on grid spacing of 12 m x 6 m pattern using inclined holes. In order to improve the definition of the ore zones, the preferred method for grade control is through RC drilling in all pits. Blast hole sampling is used for grade control in areas where RC grade control drilling is not completed. A fleet of five Shram Buggy rigs are used for RC drilling.

The mining schedule and production rate for the LOM have been established to feed the mill to its power capacity while respecting annual mining rate constraints, phase drop down rates, and minimizing truck peak requirements.

The processing rate of the Rosebel processing plant has a limit of 12.77 million tonnes per annum (Mtpa) for all rock types combined. The feed is also limited by rock hardness; which is taken into account as “Factored Tonnes”; where fresh rock has a higher factor than soft or transition. The total factored tonne limit at the mill is 8.827 Mtpa. Diluted ore tonnages were accounted for in determining the processing rate limits at plant.

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From 2019 until 2024 the plant is operated at its maximum processing capacity and from 2025 onwards, the tonnage of fresh rock increase and mill feed is reduced to approximately 9 Mtpa, due to the factored tonnes limit.

The production starts at a rate of 67.3 Mtpa in 2019 and steadily increases to a rate of 74.0 Mtpa from the RGM pits and 30 Mtpa from the Saramacca pit until 2021. The production rate stays relatively constant until 2026 from the RGM pits and is steady at 30 Mtpa from the Saramacca pit until 2029, then it starts to decline until the end of production in 2033. In the later years, production rates are reduced due to longer haulage distances, higher percentage of fresh rock, and the number of available working areas at the pit bottoms, which are not as productive as on the upper benches.

While the schedule targets softer ore in the earlier years, the proportion of hard rock in the mill feed varies from a maximum of 50% between 2019 and 2024, increases slowly from 66% to 92% between 2025 and 2029, and becomes 100% of the mill feed between 2031 and 2033.

1.2.9

MINERAL PROCESSING

The metallurgical process is conventional grinding followed by leach, carbon in leach (CIL) with a gravity circuit installation in the grinding circuit for the recovery of gravity recoverable gold. Gold recovery facilities include acid washing, carbon stripping, and electro winning, followed by bullion smelting and carbon regeneration. The process was developed to accommodate varying ratios of soft rock, transition, and hard rock ores. The process used at RGM was developed through various pilot plant programs and through additional initiatives by mill personnel to improve the process further since commissioning. Further process optimization continues to target constraints and opportunities to further increase plant capacity and performance.

The nameplate capacity of the Rosebel processing plant is 12.5 Mtpa. The plant has been operating near this capacity on a sustained long term basis. A sustained rate, at or near the nameplate design capacity, is expected for 2018 and beyond.

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1.2.10

SITE INFRASTRUCTURE

RGM site infrastructure includes:

  Site roads;
     
  Mine facilities, such as the truck shop, warehouse, and administration services;
     
  Administration buildings;
     
  Processing plant and associated buildings;
     
  Truck shop and associated buildings;
     
  Warehouse;
     
  Fuel storage;
     
  Municipal services;
     
  Aggregate plant;
     
  Camp complex;
     
Grid power supply with installed capacity of 189 megawatts (MW) with RGM power demand at 31.9 MW in 2017;
     
  5 MW solar power plant;
     
  Emergency generators;
     
  Communications and IT systems;
     
  Tailings storage facility.

The Saramacca gold project is a satellite operation to the current RGM mine site. Infrastructure on site will include:

Access road, approximately 23 km in length, between the southern end of the RGM mine site and the Saramacca deposit;
     
  ROM ore storage pad;
     
Facilities pad, including a maintenance shop, warehouse, fuel storage tanks, generator, lunch room, washroom, and office facilities;
     
  Water management ponds and ditches;
     
  A water treatment facility;
     
  Mining haul roads;
     
  Waste rock storage facilities.

1.2.11

MARKET STUDIES AND CONTRACTS

Gold is the principal commodity produced at RGM and is freely traded at prices that are widely known, so that prospects for sale of any production are virtually assured. All gold produced by IAMGOLD is in the form of doré bars, which is then shipped to a refiner who refined the doré into bullion. The bullion is then sold directly on the open market to gold trading institutions at prevailing market prices.

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RGM finalizes long term or annual contracts for all major spends which are required for the operations. Contracts are negotiated by going out on tenders. Contracts with values higher than $5 million per year include fuel, lubricants, process plant reagents, grinding media, mill liners, mining components, and RC drilling.

1.2.12

ENVIRONMENTAL STUDIES, PERMITTING, AND SOCIAL OR COMMUNITY IMPACT


1.2.12.1

RGM CONCESSION

A Feasibility Study and Environmental Impact Assessment (EIA) for the Rosebel project was first completed in 1997. After further exploration, a final Feasibility Study was completed and submitted to the Government of Suriname in August 2002. RGM received a Right of Exploitation from the Government of Suriname after the approval of the final Feasibility Study and the accompanying EIA in 2002. A Social Impact Assessment was also completed in 2002. Commercial production at Rosebel Gold Mines began in February 2004.

In 2012, RGM submitted an Environmental and Social Impact Assessment (ESIA) and obtained approval to expand the tailings storage facility (TSF). An expansion of the TSF was required to support increases in production levels and mine life. The TSF expansion consisted of the construction of a second containment basin immediately adjacent to the existing facility.

The existing Right of Exploitation provides the necessary approvals for mining and processing within the RGM concession.

1.2.12.2

SARAMACCA CONCESSION

Mining of the Saramacca deposit requires Government of Suriname approval of a Feasibility Study and an ESIA in order to proceed. Consistent with the National Institute for Environment and Development in Suriname (NIMOS) guidance, RGM initiated the ESIA process for the Saramacca project in April 2018 with the submission of an ESIA Terms of Reference (TOR) for the Saramacca project.

The scope of the Saramacca project for ESIA purposes is for the planned infrastructure and activities during the construction, operations, and closure phases of mining within the Saramacca concession and includes the transportation corridor between Saramacca and the RGM concessions. The ESIA was based on the engineering and mine planning available at the time of its submission in July 2018.

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The Review Phase of the ESIA for the Saramacca project has been completed with comments on the ESIA provided by NIMOS on October 2, 2018. RGM is currently responding to these comments and preparing a final ESIA submission. NIMOS must approve the final ESIA as a precursor to issuing a Right of Exploitation for mining within the Saramacca concession.

A Community Relations Plan with supporting guideline and procedures was developed to minimize the mine’s impact on communities and the environment.

There is one active community, Nieuw-Koffiekamp, within the boundaries of the RGM concession. Nieuw Koffiekamp is a Maroon village with a population of approximately 500 permanent inhabitants belonging primarily to the Aukan Maroon tribegroup, but with some representation by the Saramaka and Matawai tribe as well.

In the immediate surroundings of the RGM concession, there are eleven other Maroon villages that are considered by RGM communities of interest (CoIs) with the potential to be directly impacted by or have influence over RGM operations and the Saramacca project. These villages are; Marshallkreek, Klaaskreek, Nieuw-Lombe, Balingsoela, Brownsweg, and Kwakoeugron in Brokopondo District; and Nieuw Jacobkondre, Baling, Misalibi, and Bilawatra in Sipaliwini District. These, along with Nieuw-Koffiekamp are considered the direct area of influence of the company’s operations.

RGM has a regular program of engagement and community investment with all CoIs, led by the Community Relations Department. In the case of the CoIs in Brokopondo District, this relationship has been established and ongoing for many years. In the case of the four Sipaliwini CoIs of Nieuw Jacobkondre, Baling, Bilawatra and Misalibi, the program is in its beginning stages as the Saramacca project starts up. Community investment projects are selected with input from community members and traditional authorities. RGM continues to adapt and refine its community engagement and investment approach to meet community needs, particularly as considerations for post-closure sustainability and continuity become more important.

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1.2.13

CAPITAL AND OPERATING COST ESTIMATES

A total of $1,109 million of capital is planned to be spent over the remaining LOM, which equates to $7.45/t milled or $244/oz of Au. The total capital expenditure excluding expansion capital associated with the development of the Saramacca gold project is $941 million, which equates to $6.32/t milled or $207/oz of Au.

Sustaining capital, inclusive of the Saramacca deposit, is the largest capital cost estimated at $477 million, representing 44% of the LOM remaining capital expenditure.

The mine operating costs are estimated on the basis of the physical quantities of the mine plan, realistic equipment productivity assumptions, overall equipment efficiencies, and updated consumable prices.

Average mine operating costs over the LOM are estimated at $2.19/t mined, based on assumed diesel costs of the LOM of $0.63/l. The average LOM total milling cost (inclusive of power) is estimated to be $7.92/t milled. The average LOM G&A cost is $2.16/t milled and assumes an annual spend of $23 million until 2029, after which G&A costs will gradually decrease as the operation will approach the end of life.

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2

INTRODUCTION

This Technical Report was prepared by Rosebel Gold Mines N.V. (RGM), IAMGOLD Corporation’s (IAMGOLD) subsidiary, for the Rosebel Gold Mine, located in Suriname, and SRK Consulting (Canada) Inc. (SRK). The purpose of this Technical Report is to support the disclosure of the current Mineral Resource and Mineral Reserve estimates for the Rosebel Gold Mine, including the Saramacca property. This Technical Report conforms to National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101).

IAMGOLD is a mid-tier mining company with four operating gold mines and several exploration properties on three continents. IAMGOLD, through its wholly-owned subsidiary RGM, owns 95% of the RGM concession in Suriname, with the Government of Suriname holding the remaining 5%. The mine has been operating commercially since February 2004.

The Saramacca property, included in the disclosed Resource and Reserve estimate, is owned under a joint venture agreement in which the Republic of Suriname holds a 30% interest and RGM holds the remaining 70%. Details of the ownership structure are provided in Section 6. Commercial production has not started at the Saramacca property, and is currently scheduled for the second half of 2019.

All currency is in US dollars unless noted otherwise.

2.1

SOURCES OF INFORMATION

This Technical Report was prepared by RGM, IAMGOLD, and SRK personnel.

The construction of the Saramacca Mineral Resource model was a collaborative effort between IAMGOLD and SRK staff. IAMGOLD provided the technical support and assistance related to the drill database. Dr. Jean-Francois Couture, P.Geo. (APGO#0197) provided insight to the structural geology controls of gold mineralization. The data review and geological modelling were performed by Mr. Dominic Chartier, P.Geo. (OGQ #874, APGO #2775). Grade estimation and associated sensitivity analyses, and Mineral Resource classification were performed by Dr. Oy Leuangthong, P.Eng. (PEO #90563867). Pit optimization review was conducted by Mr. Nicolas Szwedska Eng. (OIQ #5010178), a BBA open pit mining engineer. The overall process was reviewed by Mr. Glen Cole, P.Geo. (APGO #1416). Additional contributions to the Technical Report were provided by Ms. Joycelyn Smith, P.Geo. (APGO #2963).

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The RGM Mineral Resource model was constructed by Raphaël Dutaut (OGQ #1301), RGM, with the help of external experts Clayton V. Deutsch (APEGA 4329) and John Manchuk, P.Eng. (APEGA #73916).

The RGM and Saramacca Mineral Reserve was estimated based on a Mine Schedule developed by Nicolas Szwedska, Eng. (OIQ #5010178) and Jeffrey Cassoff, Eng. (OIQ #5002252), with guidance and review provided by IAMGOLD Qualified Persons (QP) Adam Doucette, P.Eng. (PEO #100200823) and Michel Payeur, Eng. (OIQ #127646).

The Saramacca process testwork was carried out under the supervision of Dr. Seref Girgin, Ph.D. from BBA, Véronique Aube, Eng. M.A.Sc. (OIQ #128900) and Stéphane Rivard, Eng. (OIQ #118538) from IAMGOLD. Process review for RGM was carried by Véronique Aube and Stéphane Rivard.

By virtue of their education, membership to a recognized professional association and relevant work experience, Mr. Payeur, Mr. Dutaut, Mr. Rivard, Mr. Doucette, Dr. Leuangthong, and Mr. Chartier are QPs as this term is defined by NI 43-101. As well, Dr. Leuangthong and Mr. Chartier are independent QPs as this term is defined by NI 43-101.

2.1.1

SITE VISIT

In accordance with NI 43-101 guidelines, Dominic Chartier, P.Geo (OGQ #874, APGO #2775), visited the Saramacca gold project on January 22 to 26, 2018, accompanied by Caroline Laplante and Samuelle Gariepy, Geologists with IAMGOLD-RGM’s Suriname Exploration department.

The purpose of the site visit was to review the updated exploration database and validation procedures, review exploration procedures, examine drill core, interview project personnel, reassess geological modelling procedures, update the geological model, and collect all relevant information for the preparation of a revised Mineral Resource model and the compilation of a technical report.

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SRK was given full access to relevant data and conducted interviews with IAMGOLD-RGM personnel to obtain information on the past exploration work, to understand procedures used to collect, record, store and analyze historical and current exploration data.

Stéphane Rivard and Michel Payeur visited RGM mine site multiple times, the last one being from October 20 to 23, 2018. Adam Doucette and Raphaël Dutaut actively work on regular rotations at RGM and Saramacca and were last on site during the month of October 2018.

The QPs for this Technical Report, their responsibilities, and dates of personal inspections of RGM are provided in Section 29. The documentation reviewed, and other sources of information, are listed at the end of this report in Section 27 References.

2.2

EFFECTIVE DATES

The effective date of this Technical Report is September 23, 2018, the date of the public disclosure of the Mineral Resource and Mineral Reserve estimate for RGM and the Saramacca property.

The cut-off date for drilling and laboratory data used in the models developed for the RGM Mineral Resource estimates is January 15, 2018.

The cut-off date for the drilling and laboratory data used in the models developed for the Saramacca Mineral Resource estimates is May 22, 2018.

The effective date for the RGM Mineral Resource and Mineral Reserve estimates is September 1, 2018, which takes into account depletion up to the effective date.

The effective date for the Saramacca Mineral Resource and Mineral Reserve estimates is September 13, 2018.

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2.3

LIST OF ABBREVIATIONS

Units of measurement used in this report conform to the metric system.

Au gold   kW kilowatt
a annum   kWh kilowatt-hour
A ampere   L litre
AEM airborne electromagnetic   lb pound
Ai Bond abrasion testing   LIMS Laboratory Information Management System
AISC all-in sustaining cost   LOM life of mine
bbl barrels   L/s litres per second
btu British thermal units   m metre
BWI Bond ball mill grindability   M mega (million); molar
°C degree Celsius   m2 square metre
C$ Canadian dollars   m3 cubic metre
cal calorie   µ micron
CAPEX capital expenditure   MASL metres above sea level
CEET Comminution Economic Evaluation Tool   µg microgram
cfm cubic feet per minute   m3/h cubic metres per hour
CIL carbon in leach   mi mile
cm centimetre   min minute
cm2 square centimetre   µm micrometre
CoG cut-off grade   mm millimetre
CWI Bond Crusher Work Index   MMI mobile metal ions
CWS capitalized waste stripping   mph miles per hour
d day   MVA megavolt-amperes
D1 first phase of deformation   MW megawatt
D2 second phase of deformation   MWh megawatt-hour
DD diamond drill   NQ 47.6 mm drill core size
dia diameter   oz Troy ounce (31.1035g)
dmt dry metric tonne   oz/st, opt ounce per short ton
dwt dead-weight ton   PAL Pulverize and Leach
DWT JK Drop-Weight Test   pH potential of hydrogen
°F degree Fahrenheit   ppb part per billion
ft foot   ppm part per million
ft2 square foot   psia pound per square inch absolute
ft3 cubic foot   psig pound per square inch gauge
ft/s foot per second   QA/QC quality assurance/quality control
g gram   Qemscan Quantitative Evaluation of Minerals by SCANning electron microscopy
G giga (billion)   UJV Unincorporated Joint Venture
Ga billion years   US$ United States dollars
Gal Imperial gallon   RC reverse circulation
g/L gram per litre   RL relative elevation
GMD Geological Mining Department   ROE Right of Exploration
Gpm Imperial gallons per minute   RQD rock quality designation
g/t gram per tonne   s second
gr/ft3 grain per cubic foot   SAG Semi Autogenous Grinding Mill
gr/m3 grain per cubic metre   SMC drop-weight testing

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G&A general and administrative   SPI Semi Autogenous Grinding Mill Power Index
ha hectare   SRM standard reference material
hp horsepower   st short ton
hr hour   stpa short ton per year
HQ 63.5 mm drill core size   stpd short ton per day
Hz hertz   t metric tonne
IASB International Accounting Standards Board   tpa metric tonne per year
IFRIC International Financial Reporting Interpretations Committee   tpd metric tonne per day
in. inch   TTG tonalite-trondjhemite-granodiorite
in2 square inch   US$ United States dollar
J joule   USg United States gallon
IP Induced polarization   USgpm US gallon per minute
k kilo (thousand)   V volt
kcal kilocalorie   W watt
kg kilogram   wmt wet metric tonne
km kilometre   wt% weight percent
km2 square kilometre   w/v Weight per volume
km/h kilometre per hour   w/w weight per weight
kPa kilopascal   yd3 cubic yard
kVA kilovolt-amperes   yr year

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3

RELIANCE ON OTHER EXPERTS

This Technical Report was prepared by RGM, IAMGOLD, and SRK personnel. For the purpose of this report, QPs have relied on the following subject matter experts:

Section 4 – Property Description and Location

The QP has relied on ownership information provided by Ms. Sharmila Jadnanansing, IAMGOLD’s legal counsel in Suriname, regarding title to the RGM concession. Ms. Jadnanansing provided a legal review and opinion dated October 18, 2018. This information was used in Sections 1 and 4 of this report.

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4

PROPERTY DESCRIPTION AND LOCATION


4.1

RGM PROPERTY

The Gross Rosebel concession (RGM concession) (Geological Mining Department (GMD) No. 468/02) covers an area of 170.0 km² in the north central part of the Republic of Suriname at a latitude of 5° 25’ North and a longitude of 55° 10’ West. The RGM concession lies in the district of Brokopondo, between the Suriname River to the east and the Saramacca River to the west, approximately 80 km south of the capital city of Paramaribo (Figure 4-1).

4.1.1

LAND TENURE

The Rosebel Gold Mine area consists of the following concessions: Gross Rosebel concession (or the RGM concession), which contains the Royal Hill, Mayo, Roma, Rosebel, Koolhoven, Pay Caro, East Pay Caro, and J Zone deposits, and seven exploration concessions (Headley’s Reef, Charmagne 1, Charmagne 2, Charmagne West, Thunder Mountain, Anjoemara en Lef Resources, and Brokolonko), all located on contiguous ground (Figure 4-2).

All these concessions are owned by RGM which is a Surinamese company created for the purpose of exploring for and developing all minerals including gold, precious metals, base metals and stones and operating the Rosebel Gold Mine. IAMGOLD owns a 95% interest in RGM, while the Republic of Suriname has a 5% free-carried interest.

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FIGURE 4-1     LOCATION MAP

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4.1.2

MINING PERMIT

The rights to the Rosebel mine property were initially held through a Right of Exploration (ROE) granted by the Ministry of Natural Resources, valid and renewable for two-year periods. The ROE was renewed and extended for two years as from February 25, 2002, in favour of Golden Star. On May 16, 2002, Golden Star assigned, conveyed, and transferred its Gross Rosebel ROE to RGM. Finally on December 16, 2002, RGM was granted a 25-year renewable Right of Exploitation for the Rosebel mine from the Republic of Suriname, following the Government’s approval of the updated feasibility study and environmental impact assessment. The term of the Rosebel concession can be extended by a period of 15 years from its current expiration date.

In addition to the 5% interest in RGM, the Republic of Suriname receives, through a Government owned company, a 2% fixed royalty of production paid in-kind. Further, RGM pays an excess royalty of 6.5% in case the gold price is in excess of US$425/oz. Royalties on production are also paid out to Euro Resources SA (Euro Resources). The royalty is applicable to the first seven million ounces of gold produced, with payments based on 10% of the excess gold market price above US$300/oz for soft and transitional ore, and above US$350/oz for hard rock ore, after deduction of royalties to the Republic of Suriname.

The Republic of Suriname also collects various taxes and duties as specified by the Mineral Agreements and its Amendments, Mining Code, and the applicable Tax Laws, such as corporate taxes, payroll taxes, consent and static rights, as well as surface rights.

4.1.3

EXPLORATION PERMITS

The RGM concession is surrounded by seven ROEs which currently cover a total area of 948.20 km2 and by Project Lands covering a total area of 10.2 km2 (Figure 4-2). The Minister of Natural Resources has approved the request of RGM for the use of Triangle area as a Project with a total area of 44.95 km². The approval was communicated by letter dated June 29, 2018.

Two exploration concessions are directly adjacent to the RGM concession and include Headley’s Reef and Thunder Mountain concessions which were in the past renewed in favour of Golden Star and thereafter assigned, conveyed and transferred to RGM simultaneously with the RGM concession. The total area of the two ROEs is 424.15 km2 and surrounds the RGM concession.

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The Overman project is located within the Charmagne property, located about 12-15 km north of the RGM concession. The Charmagne property consists of four concessions that involve two companies: Charmagne Mining Company who was the registered owner of three ROEs and LEF Resources who was the registered owner of one ROE. RGM negotiated the option to acquire 100% interest in the mineral rights of the two companies and option agreements were signed in January 2008. The options were exercised by RGM and duly filed with the relevant Government Authorities, followed by issuance of rights of exploration to RGM as mentioned under the Second Amendment.

Another ROE has been granted to RGM directly to the west of the Charmagne property and is referred to as Charmagne West.

The Brokolonko exploration concession was granted to RGM on February 7, 2018 after RGM applied for the ROE.

Information related to the exploration concessions is listed in Table 4-1. The Minister of Natural Resources has recently re-issued the seven exploration rights as agreed in the Second Amendment 2013. The seven ROEs are in good standing and valid until August 2020 subject to two extensions of two years as provided in the Mining Decree 1986 of the Republic of Suriname.

TABLE 4-1     EXPLORATION PERMIT DETAILS

Concession Name GMD No. Expiry Date
(date of validity)
Surface
Area
(ha)
Surface
Area (km2)
ROSEBEL MINE Area        
Gross Rosebel Mine Exploitation Concession 2027-12-16 17,000 170.00
  GMD No. 468/02      
    Total 17,000 170.00
         
Thunder Mountain Exploration Concession 2020-08-25 28,850 288.50
  GMD No. 311/16      
Headley's Reef Exploration Concession 2020-08-25 13,565 135.65
  GMD No. 312/16      
    Total 42,415 424.15

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Concession Name GMD No. Expiry Date
(date of validity)
Surface
Area
(ha)
Surface
Area
(km2 )
CHARMAGNE Property        
         
Charmagne - LEF Exploration Concession 2020-08-25 300 3.00
  GMD No. 317/16      
Charmagne 1 Exploration Concession 2020-08-25 5,831 58.31
  GMD No. 314/16      
Charmagne 2 Exploration Concession 2020-08-25 3,281 32.81
  GMD No. 313/16      
Charmagne - Anjoemara Exploration Concession 2020-08-25 156 1.56
  GMD No. 316/16      
    Total 9,568 95.68
CHARMAGNE WEST Property        
         
Charmagne West Exploration Concession 2020-08-25 10,768 107.68
  GMD No. 315/16      
         
BROKOLONKO Property        
         
Brokolonko Exploration Concession 2021-02-07 10,082.5 100.83
  GMD No. 1157/17      
         
SARAMACCA Property        
         
Saramacca Exploration Concession 2019-08-31 4,986 49.86
  GMD No. 516/16      
         
    TOTAL SURFACE 94,819.5 948.20

For information on the Saramacca exploration concession see Section 4.2, Saramacca property.

The Mining Decree 1986 of Suriname states that, exploration concessions are held for a maximum of seven years (an initial term of three years, a first extension of two years, and a second extension of two years). After the initial three years, 25% relinquishment is required followed by 25% in the subsequent two extensions, and then a final relinquishment after the seventh year. Some exploration concessions are currently in the renewal process. The Mining Decree 1986 gives the ROE holder the exclusive right to explore for the minerals requested on the surface and subsurface within the boundaries of the exploration concession.

The Mining Decree 1986 of Suriname also provides for the holder of the ROE to apply for a Right of Exploitation.

The different ROEs fall also within the Area of Interest or the new Unincorporated Joint Venture (UJV) area as defined in The Second Amendment of the Mineral Agreement with the Republic of Suriname of June 6, 2013. The Second Amendment establishes a UJV vehicle under which RGM holds a 70% participating interest and the Republic of Suriname could acquire a 30% participating interest on a fully-paid basis, via a fully owned designated company.

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4.1.4

SURFACE RIGHTS

Surface rights in the area of the Gross Rosebel Mining Concession belong to the Republic of Suriname. Utilization of the surface rights is granted by the RGM concession under certain conditions. All the annual fees and taxes relating to Gross Rosebel and other ROEs have been paid to date and the concessions are in good standing.

4.1.5

PERMITTING REQUIREMENTS AND STATUS OF PERMITS

The Right of Exploitation of the RGM concession property is governed by the following major Instruments, Agreements, and National Laws:

  1.

The Instrument granting the Right of Exploitation to RGM under GMD No. 468/02.

     
  2.

Approval Instrument issued by the Ministry of Natural Resources to transfer the ROE from Golden Star to RGM.

     
  3.

The Second Amendment to the Mineral Agreement, June 6, 2013.

     
  4.

The Mineral Agreement April 7, 1994, as amended and supplemented on March 13, 2003.

     
  5.

The Mining Decree of Suriname May 8, 1986.

     
  6.

National Institute for Environment and Development in Suriname (NIMOS) for the Environmental and Social Impact Assessment (ESIA).

The ROE for Minerals is granted by the Ministry of Natural Resources subject to terms and conditions stipulated in the Mining Decree 1986. Following issuance of such a right the holder is required to file quarterly and annual reports with the GMD.

Furthermore, the instrument granting the ROE enumerates all the conditions which need to be considered and complied with during the exploration phase. There are no specific pre-environmental requirements in this phase, however, the ROE stipulates that exploration activities should be conducted conform to Environmental Standards of the World Bank.

4.2

SARAMACCA PROPERTY

The Saramacca gold project is located approximately 25 km southwest of the Rosebel Gold Mine milling facility (Figure 4-2). The Saramacca property covers an area of approximately 4,986 ha, straddling the Brokopondo and Sipaliwini districts of Suriname. To the northeast, the property is adjoined to the Headley’s Reef concession, which is 95% owned by RGM and 5% owned by the Republic of Suriname. The property is also adjacent to the Moeroekreek exploration concession, which is under a lease agreement with the option to acquire this concession from Sarafina N.V., a Surinamese mining company.

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The centre of the property is located at an approximate latitude of 4° 55’ North and a longitude of 55° 22’ West.

4.2.1

MINERAL TENURE

RGM holds a 70% interest in the Saramacca gold project (IAMGOLD’s effective interest is 66.5%) . The mineral rights comprise a single exploration concession (GMD No. 516/16) covering an area of 4,986 ha (Figure 4-2).

On August 30, 2016, IAMGOLD signed a Letter of Agreement (LOA) with the Republic of Suriname to acquire the rights to the Saramacca property, with the intent of defining an NI 43-101 Mineral Resource within 24 months. The terms of the LOA included an initial payment of US$200,000 which enabled immediate access to the property for IAMGOLD-RGM’s exploration team to conduct due diligence, as well as access to historical data from previous exploration activity at the Saramacca property.

On September 29, 2016, having been satisfied with the results of the due diligence, IAMGOLD ratified the LOA by Ratification Letter and amended the amended LOA on December 12, 2016 to acquire the Saramacca property. IAMGOLD subsequently paid $10 million in cash and agreed to issue 3.125 million IAMGOLD common shares to the Republic of Suriname in three approximately equal annual instalments on each successive anniversary of the date the ROE was transferred to RGM. The ROE to the Saramacca property was legally transferred by Notarial Deed to Rosebel on December 14, 2016 and subsequently registered as such in the formal Mortgage Registry office, the GLIS Management Institute.

In addition, the amended LOA provides for a potential upward adjustment to the purchase price to a maximum of $10 million, based on the contained gold ounces identified by RGM in CIM Measured and Indicated Mineral Resource categories, within a certain Whittle shell within the first 24 months.

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The Saramacca property falls within the Area of Interest or the Unincorporated Joint Venture (UJV) area as defined in The Second Amendment of the Mineral Agreement with the Republic of Suriname of June 6, 20131.

The Second Amendment establishes a UJV under which Rosebel holds a 70% participating interest and the Republic of Suriname will acquire a 30% participating interest on a fully-paid basis, via a fully owned designated company.

The Mining Decree of 1986 of Suriname states that, exploration concessions are held for a maximum of seven years; an initial term of three years, a first extension of two years and a second extension of two years. After the initial three years, 25% relinquishment is required, followed by 25% in the subsequent two extensions, and then a final relinquishment after the seventh year. The Saramacca concession is currently in the second year of exploration of the initial three years.

The Mining Decree of 1986 of Suriname also provides for the holder of the ROE to apply for a Right of Exploitation.

For the Saramacca gold project, the granting of the Right of Exploitation is subject to specific terms and conditions as stated in the Second Amendment under the condition that an Environmental and Social Impact Assessment (ESIA) is required relative to the planned exploitation activities and any impacts resulting thereof, in accordance with the Surinamese law.

4.2.2

UNDERLYING AGREEMENTS

IAMGOLD is currently the registered owner of 95% in RGM and RGM is currently the registered owner of 100% interest in the Saramacca exploration concession. RGM is subject to the Unincorporated Joint Venture vehicle under which RGM will hold a 70% participating interest and the Republic of Suriname will acquire a 30% participating interest on a fully-paid basis.

_________________________________________________
1
The Second Amendment of the Mineral Agreement between Republic of Suriname, Grasshopper Aluminium Company N.V., IAMGOLD Corporation and Rosebel Gold Mines N.V. of April 7, 1994 and as amended on March 13, 2003.

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4.2.3

PERMITS AND AUTHORIZATION

The ROE of the Saramacca property is governed by the following major Instruments, Agreements, and National Laws:

  1.

The letter of Agreement dated August 30, 2016.

     
  2.

Ratification Letter dated September 29, 2016.

     
  3.

Amendment to the Letter of Agreement dated December 12, 2016.

     
  4.

The Notarial Deed of transfer of the Right of Exploration of the Saramacca property dated December 12, 2016, from the wholly Republic of Suriname owned Company, NV 1, to Rosebel Gold Mines N.V.

     
  5.

The Instrument granting the Right of Exploration under GMD No. 516/16.

     
  6.

Approval Instrument issued by the Ministry of Natural Resources to transfer this Right of Exploration (GMD No. 706/16).

     
  7.

Mortgage extract from the GLIS Management Institute effectuating the transfer of the title to the Saramacca property to Rosebel Gold Mines N.V. as of December 14, 2016.

     
  8.

The second amendment to the Mineral Agreement dated June 6, 2013.

     
  9.

The Mineral Agreement of April 7, 1994, as amended and supplemented on March 13, 2003.

     
  10.

The Mining Decree of May 8, 1986 (Mining Law of Suriname).

     
  11.

National Institute for Environment and Development in Suriname (NIMOS) for the Environmental and Social Impact Assessment (ESIA).

The ROE for Minerals are granted by the Ministry of Natural Resources, subject to terms and conditions stipulated in the Mining Decree of 1986. Following issuance of such a right, the holder is required to file quarterly and annual reports with the GMD.

Furthermore, the instrument granting the ROE enumerates all the conditions which need to be considered and complied with during the exploration phase. There are no specific pre-environmental requirements in this phase, however, the ROE stipulates that exploration activities should be conducted in a way which conform to the Environmental Standards of the World Bank.

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4.3

DISCUSSION

Other than the royalty on the revenues from mineral production to the Republic of Suriname as well as royalties to Euro Resources, IAMGOLD is not aware of any royalties, back-in rights, payments, or other agreements and encumbrances to which the property is subject.

IAMGOLD is not aware of any environmental liabilities on the property. IAMGOLD has all required permits to conduct the proposed work on the property. IAMGOLD is not aware of any other significant factors and risks that may affect access, title, or the right or ability to perform the proposed work program on the property.

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5

ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY


5.1

TOPOGRAPHY, ELEVATION, AND VEGETATION

The physical geography of Suriname is divided into three areas: the Coastal Plain, the Savannah Belt, and the Guiana Shield. The Guiana Shield comprises approximately 80 to 85% of the total land area of Suriname, and extends into French Guiana to the east, Brazil to the south, and Guyana, Columbia and Venezuela to the west. RGM is located within the Guiana Shield.

The Guiana Shield is mostly low-lying (below 250 m) and hilly (with discrete ranges reaching 1,200 metres above sea level (MASL). Most of Guiana Shield is pristine and covered with dry land forest, except where poor soil or repeated burning of the vegetation have led to the creation of savannas.

The Saramacca gold project lies along the Brokolonko Ridge, a northwest trending ridge of nearly 30 km and reaching an elevation of 530 MASL. Although the ridge can locally be steep, the Saramacca property is located on the northeastern side of the ridge in an area where slopes are moderate and the crest remains below 450 m. The ridge is dissected by the Saramacca River near its northwestern extremity.

The ridge crest is generally covered by a thick duricrust layer of up to 6 m in thickness. Slopes are either pisolithic clays, clays or colluvium. A mature tropical forest grows on the Brokolonko ridge and on the surrounding lower-lying plains. Rock outcrops are scarce and limited to road cuts and creek beds.

5.2

ACCESSIBILITY

There are presently two access routes from Paramaribo to the Rosebel project. One route utilizes a 30 km paved road which connects Paramaribo to Paranam. From Paranam, a paved road courses south following the Afobaka road. From there an unpaved road travels south and west to reach the property. The other route is a paved road which connects Paramaribo to the international airport at Zanderij. A newly paved road connects Zanderij to the Afobaka road halfway between Paranam and Afobaka. The route then follows the Afobaka, Brownsweg, and Nieuw-Koffiekamp roads until reaching the property access road. Travel distance for both routes from Paramaribo is approximately 100 km.

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The Saramacca gold project is located approximately 25 km southwest of the Rosebel Gold Mine milling facility. Access is via the paved Afobaka road heading south from Paramaribo and then to Brownsweg. From Brownsweg, the road continues south to Atjoni/Pokigron. The turnoff to Saramacca occurs 25 km after Brownsweg. The project is located a further 14 km westward along a reasonable quality all weather active logging road. During the dry season, it takes approximately 1.5 hours to travel from the Rosebel Gold Mine site to the Saramacca concession.

A 36 km unsealed road was built from the Rosebel mine site to the Saramacca concession in 2016. Access roads in the area are typically saprolite and are not accessible year-round, as they wash out or become hazardous in the wet seasons. The logging road to the project area is generally well maintained and can be driven on with caution during the wet season.

5.3

CLIMATE AND LENGTH OF OPERATING SEASON

The climate of Suriname is classified as tropical, i.e. warm during the entire year with the mean temperature of the coldest month being higher than 20°C. The average monthly rainfall is greater than 60 mm in the driest month(s). Like much of Suriname, the Rosebel property is characterized by consistently warm temperatures and high humidity with little seasonal variation.

Suriname weather is dictated mainly by a north-east and south-east wind called the Inter-Tropical Convergence Zone (“ITC” zone, also known as the “Equatorial Trough”). The ITC zone passes over Suriname twice a year and results in four seasons:

  Late February to late April, a short dry season;
     
  Late April to mid-August, a long rainy season;
     
  Mid-August to early December, a long dry season;
     
  Early December to late February, a short rainy season.

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Exploration and production activities can be carried out in all seasons.

Weather data is collected on the Rosebel property on a regular basis since 2003 using a manual weather station (Old Camp) and since 2005 using an automated weather station (tailings area).

Based on Old Camp data from 2004 to 2016, the average annual precipitation was estimated to be 2,288 mm per year, while the mean annual temperature for Rosebel is 25.0°C. The daily fluctuation in temperature in the interior of Suriname, including the Rosebel area, is approximately 10 to 12°C. The average monthly relative humidity at Rosebel ranges from 84.8% in February to 93.5% in June, with an annual average of 89%. This relative humidity trend results from rainfall and temperature changes.

The most common wind direction is from the east (approximately 20% of the time) followed by the south-east (approximately 9% to 14% of the time). Based on data, the Rosebel site does not experience sustained strong winds, i.e. hourly average wind speeds greater 5.0 m/s. The most common wind speed range is 1.0 m/s to 2.5 m/s.

5.4

SURFACE AREA AND PHYSICAL RESOURCES

The Rosebel area currently hosts the small village of Nieuw-Koffiekamp, located approximately 2 km from the old exploration base camp and about 1 km from the Royal Hill pits. The village consists of approximately 500 permanent inhabitants belonging primarily to the Maroon group, who are descendants of African slaves.

The economy of the village remains dependent on the Surinamese coastal economy. Main activities include subsistence agriculture on relatively poor land, small-scale gold mining, forestry, and trade.

The village, originally named Koffie Kamp, relocated to its present site in 1964 when the previous site was flooded as a result of the development of the Brokopondo hydroelectric project. Relations between the project management and the villagers have occasionally been strained due primarily to the conduct of illegal mining activities on the Rosebel property by the villagers and others.

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Other than the road between Paramaribo and the mine site, the local infrastructure consists of site roads that include access from the main gate to the camp, pits, tailing area, the process plant area, and administration building area. These roads are constructed using laterite and are typically between 10 m and 30 m wide, depending on the equipment in use. Culverts are installed and ditching is installed to provide adequate drainage.

An existing airstrip with an approximate length of 1.2 km is used for emergency evacuation. The airstrip is located 6 km from the administration building.

The camp complex is located approximately 0.5 km to the south of the process plant and truck shop/administration building. The camp complex includes a kitchen, recreation area, camp offices, and different types of dormitories.

Miscellaneous outbuildings such as core storage, laboratories, security gates, lunchrooms, and solar panels are found throughout the concession.

Electrical energy is purchased directly from the Surinamese government. Power is delivered from the Afobaka hydroelectric generating station.

Potable and process water is supplied from water wells located along the Mamanari Creek near the camp complex.

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6

HISTORY


6.1

RGM - OWNERSHIP, EXPLORATION, AND DEVELOPMENT HISTORY

Documentation on the history of gold production on the Rosebel property is fragmentary. Records were either not kept or, in most cases, have disappeared. Gold was first discovered in the area in 1879, when approximately 600 small scale miners were reported to be working on the property, and since that time approximately half of the recorded production of Suriname has been produced from the district.

Between 1885 and 1939, several large companies exploited alluvial material, surface deposits, and veins. Various methods of mechanized mining were tried, including dredges, stamp mills, and hydro-sluicing, with varying degrees of success. The larger companies eventually subleased concessions to miners, who continued exploitation using manual recovery methods. Some of the more prominent companies that operated in the area, and for which records still exist, are listed below.

Guyana Gold Placer Company operated dredges in Niew Foto and Groote Louis Creeks of the Koolhoven area circa 1910. That company sub-leased some ground in the Koolhoven area to an American group, who underground-mined on a series of quartz veins up to 5 m wide. Production was said to include a “nugget” of nearly eight ounces.

De Jong Brothers owned the Royal Hill area, which was mined manually by adits, shafts, and open cuts during the 1920s and early 1930s. Records indicate that from 1924 to 1933 the average output was 1,600 ounces of gold a year.

White Water Mines Ltd. acquired the aforementioned area from De Jong in 1935. Widespread veins were mined by shafts and adits, ore being carried to a central mill by narrow-gauge railway. Production ceased in 1939, at the start of the Second World War, and no record is available.

Van Emden Gold Mines Ltd. operated three mines in the area in the 1930s: Mayo, Koolhoven, and Donderbari. These were the best-planned, operated, and capitalized operations to date, using large-size ball and stamp mills and extensive narrow-gauge railway systems.

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The Suriname Government, which operated the deposit intermittently from 1950 to 1952, reports some production from Royal Hill. Since that time, several companies or individuals have carried out resource estimations on the Rosebel gold deposits. Historical Mineral Resource estimates presented in this section are historical in nature and should not be relied upon. They are superseded by the Mineral Resource estimates discussed in Section 14 of this Technical Report.

6.1.1

PRIOR OWNERSHIP


6.1.1.1

SURPLACER – 1976

In 1974, the present property was granted to Surplacer, a joint venture between Placer Development Ltd. (Placer) of Vancouver, and the Surinamese Government. The exploration program identified several kilometre-long gold anomalies, located along two major trends, one in the North and the other in the South of the area. Detailed follow-up work, involving 900 hand auger holes, 4 km of bulldozer trenches and 43 reverse circulation (RC) drill holes, partially delineated surficial and near-surface gold mineralization: the Royal Hill, Mayo, and Rosebel areas in the south and Pay Caro in the north. When Placer terminated the joint venture and left Suriname in 1977, the resource estimate indicated nearly 700,000 ounces of gold.

6.1.1.2

GRASSALCO – 1984

On July 26, 1979 the Rosebel property was awarded to NV Grassalco (Grassalco), which carried out a new resource estimate based on 1,500 hand auger holes, and excluded the Placer data. Grassalco was forced to abandon operations in the middle of 1985, due to an unstable political situation.

6.1.1.3

SMITH – 1987

The last work performed in respect of the Rosebel property and prior to its acquisition by Golden Star Resources, was a Ph.D. thesis by I.H. Smith, of the University College of Cardiff, Wales in 1987. That thesis evaluated resources from several gold deposits in Suriname using a statistical interpretation of results.

6.1.1.4

GOLDEN STAR

Golden Star acquired the ROE to the Rosebel property pursuant to a Preliminary Mineral Agreement between Golden Star, Grassalco, and the Government of Suriname dated May 8, 1992. The 1994 Mineral Agreement between Golden Star, Grassalco, and the Government of Suriname was signed on April 7, 1994 and replaced the 1992 agreement; in accordance with the 1994 Mineral Agreement, Golden Star was granted the ROE for the Rosebel property for five years.

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Golden Star entered into an agreement with Cambior Inc. (Cambior) on June 7, 1994, granting Cambior the option to earn an undivided 50% of Golden Star’s interest in the 1994 Mineral Agreement and the Rosebel property. This agreement provided that Cambior shall exercise its option by funding approximately $6.1 million in exploration and development expenditures on the Rosebel property by June 30, 1996.

A Feasibility Study and an Environmental Impact Statement were filed with the Government of Suriname in May 1997. Following additional drilling on the property, a revised Feasibility Study was submitted to the Government of Suriname in December 1997. In 1998, 1999, and 2000, the Rosebel project remained on care and maintenance.

In December 2000, a Pre-feasibility Study was delivered to the Ministry of Natural Resources covering only the mining and processing of the soft rock and transition ore portions of the Rosebel deposits, then reducing the project’s estimated capital expenditures to $80 million from the $175 million contemplated in the original 1997 Feasibility Study. The Feasibility Study completed in August 2002 replaces both the November 1997 and December 2000 studies.

On October 26, 2001, Cambior agreed to acquire Golden Star’s 50% interest in the Rosebel property. Golden Star agreed to sell its 50% interest in Rosebel for a cash consideration of $8 million and a gold price participation right on future production from Rosebel; $5 million was paid at closing (May 2002) and the remainder in three equal installments were paid over a three-year period. Under its gold price participation right, Golden Star would receive a quarterly payment of an amount equal to 10% of the excess, if any, of the average quarterly market price above US$300/oz for gold production from RGM’s soft and transitional rock portions and above US$350/oz from RGM’s hard rock portion, up to a maximum of seven million ounces produced. In addition, Golden Star transferred its rights in the Headley’s Reef and Thunder Mountain exploration properties adjacent to Rosebel.

Commercial production at Rosebel Gold Mines began in February 2004. In 2004, Golden Star sold the royalty interest in production at the Rosebel property to Euro Resources (formerly Guyanor Resources SA).

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6.1.2

IAMGOLD

In November 2006, IAMGOLD acquired a 100% interest in Cambior (the previous owner of RGM), thereby acquiring 95% of RGM.

In December 2008, IAMGOLD acquired 84.55% of the current share capital of Euro Resources.

In June 2013, IAMGOLD, RGM, Grasshopper Aluminum Company N.V., and the Republic of Suriname executed the Second Amendment to the Mineral Agreement. The Second Amendment created a new Unincorporated Joint Venture vehicle (UJV) in which the Republic of Suriname would hold, through NV1, a wholly owned subsidiary of the Republic, a paid 30% interest and RGM would hold a 70% interest. Under the terms of the Second Amendment, NV1 has been granted an option to acquire an increased interest in production from the RGM concession if RGM approves a Significant Expansion of the existing mill and if NV1 elects to participate in the Significant Expansion by funding 30% of the capital required for the expansion. A Significant Expansion is defined in the Second Amendment as an increase in the milling capacity of the Rosebel mill of 3.0 Mtpa or as otherwise agreed by the UJV partners, NV1, and RGM. At the present time, RGM has not approved a Significant Expansion and the UJV partners are not actively evaluating a potential Significant Expansion of the Rosebel mill.

In December 2015, IAMGOLD announced the closing of a simplified tender offer for Euro Resources through the Euronext Paris. At the closing of the simplified tender, in conjunction with purchases made by IAMGOLD through the facilities of the Euronext Paris since the submission of the draft offer to the French Autorité des Marchés Financiers, IAMGOLD owns and controls approximately 90% of the outstanding common shares of Euro Resources.

6.1.3

RGM - PAST PRODUCTION

Table 6-1 summarizes production from 2004 through 2017.

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TABLE 6-1     PAST PRODUCTION

    Total 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017
Ore Mt 161.4 6.3 6.9 7.0 7.8 8.9 12.4 13.4 13.3 14.1 13.6 13.9 14.1 14.7 15.0
Grade g/t Au 1.02 1.73 1.57 1.40 1.27 1.26 1.22 1.05 0.98 0.97 0.89 0.80 0.74 0.78 0.72
Waste Mt 517.4 10.6 15.1 21.6 28.2 35.5 41.0 38.9 39.8 43.1 47.8 49.2 49.4 49.4 47.8
Total Mt 678.7 16.9 21.9 28.6 36.0 44.4 53.4 52.3 53.1 57.2 61.4 63.1 63.5 64.1 62.8
Strip Ratio   3.2 1.7 2.2 3.1 3.6 4.0 3.3 2.9 3.0 3.1 3.5 3.6 3.5 3.4 3.2
Milled Mt 148.3 5.1 7.2 7.7 7.5 8.3 11.1 12.8 12.9 12.8 12.3 12.9 12.3 12.6 12.8
Ounces Produced ‘000 oz 4,826 282 339 300 277 331 412 416 406 401 386 344 302 312 318

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6.2

SARAMACCA – OWNERSHIP, EXPLORATION, AND DEVELOPMENT HISTORY

Exploration in Suriname began between 1600 and 1800 when British, Dutch, and French colonists explored the main rivers of the Guianas in search for gold and other resources. Expeditions at the end of the 19th century evolved to be more political, centred around progressing geological research for economic exploitation of the natural resources in the interior, especially for gold.

In more recent years the Republic of Suriname, through a geological reconnaissance program lead jointly by the Geological and Mining Service of Suriname (Geologisch Mijnbouwkundige Dienst van Suriname, abbreviated to GMD) and the University of Amsterdam, conducted large-scale mapping over vast portions of the country, including the Saramacca area. Various photogeological studies, field studies, and mapping programs, focussing primarily on gold and bauxite, were performed until the 1970s by the GMD. No specific study appears to have been executed on the Saramacca gold project area during that time.

6.2.1

PRIOR OWNERSHIP AND CHANGES

The first recorded exploration on the Saramacca gold project was undertaken by Golden Star in 1994. During this time, the Saramacca concession was part of a larger grants package known as Kleine Saramacca.

In August 2006, Golden Star signed a joint venture with Newmont Mining Corporation (Newmont), whereby Golden Star would remain the operator of the Saramacca gold project. In 2007 and 2008 Newmont funded all exploration activities at Saramacca, with Golden Star personnel managing the project. During 2009, Newmont earned a 51% interest in the Saramacca gold project by spending $6.0 million on exploration expenditures and took over management of the programs.

In November 2009, Golden Star entered into an agreement to sell their interest in the Saramacca joint venture to Newmont for approximately $8.0 million. In December 2012, all requirements for the sale and transfer were met, and ownership and control of the Saramacca gold project was turned over to Newmont for a total consideration of $9.0 million in cash.

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In 2013, the property was returned to the Republic of Suriname. RGM signed a Letter of Agreement with the Republic of Suriname on August 30, 2016, to acquire the rights to the Saramacca gold property.

6.2.2

PREVIOUS EXPLORATION WORK

The Saramacca property has been explored since the 1990s, principally by Golden Star and later as a joint venture between Golden Star and Newmont. Much of the work focussed on the discovery and delineation of Anomaly M, which was the subject of successive auger and diamond drilling (DD) programs, with over 200 auger holes and 90 DD holes completed in the anomaly area. Anomaly M became the Saramacca gold project after IAMGOLD-RGM carried out exploration work in 2016 and 2017.

6.2.3

PREVIOUS MINERAL RESOURCE ESTIMATES

Historical Mineral Resource estimates presented in this section are superseded by the Mineral Resource estimate discussed in Section 14 of this Technical Report. The information presented in this section is relevant to provide context but should not to be relied upon.

In October 2017, SRK prepared a NI 43-101 Technical Report (SRK, 2017b) in support of the maiden Mineral Resource estimate disclosed by IAMGOLD-RGM on August 28, 2017 for the Saramacca property (Table 6-2).

The 2017 Mineral Resource statement can be found on SEDAR (www.sedar.com), filed under IAMGOLD.

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TABLE 6-2     PREVIOUS MINERAL RESOURCE STATEMENT FOR SARAMACCA
PROPERTY, SRK CONSULTING (CANADA) INC., EFFECTIVE AUGUST 28, 2017

Category Weathering
Zone
Cut-off Grade
(g/t Au)
Tonnes
(000)
Grade
(g/t Au)
Contained
Ounces (000)
100% Basis
Indicated Laterite 0.25 2,372 1.20 91
Saprolite 0.25 5,573 2.43 436
Transition 0.35 2,526 2.17 176
Fresh 0.45 3,973 2.49 318
Total Indicated     14,444 2.20 1,022
           
Inferred Laterite 0.25 4,455 0.69 98
Saprolite 0.25 4,790 0.82 126
Transition 0.35 1,349 1.97 86
Fresh 0.45 3,039 2.13 208
Total Inferred     13,632 1.18 518

Notes:

  1.

Mineral Resources are not Mineral Reserves and have not demonstrated economic viability.

  2.

CIM definitions were followed for classification of Mineral Resources.

  3.

All figures have been rounded to reflect the relative accuracy of the estimates.

  4.

Reported at open pit resource cut-off grades of 0.25 g/t Au for laterite and saprolite, 0.35 g/t Au for transition and 0.45 g/t Au for fresh.

  5.

Reported within a conceptual open pit shell optimized at a gold price of US$1,500 per troy ounce and assuming metallurgical recoveries of 97% for laterite and saprolite, 76% for transition and 82% for fresh.


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7

GEOLOGICAL SETTING AND MINERALIZATION


7.1

REGIONAL GEOLOGY

The RGM concession lies within a greenstone belt of the Paleoproterozoic Guiana Shield which stretches from the Amazon River in Brazil to the Orinoco River in Venezuela and covers an area of more than 900,000 km2. Most of the rocks of the Guiana Shield have been formed during the Paleoproterozoic Transamazonian or Late-Transamazonian orogeny. In its general distribution, the Proterozoic part of the Guiana Shield shows a south-westward younging of units with: tonalite-trondjhemite-granodiorite (TTG) greenstone belt to the North, granitoid succession mainly in the central part, and Late Paleoproterozoic to Mesoproterozoic volcanic, intrusive, and sedimentary rocks in the southernmost part (Figure 7-1). The geological evolution of the Guiana Shield is divided in four distinct stages which are either related to formation or reworking of in-place rocks. The four stages are: Formation of the Archean basement – Main Transamazonian orogeny – Late Transamazonian orogeny – subsequent Proterozoic and Paleozoic anorogenic events.

The main Transamazonian orogeny (D1), constrained between 2.26 -2.08 Ga, consisted of a crustal growth event that generated the TTG – greenstone belts found North of the Guiana Shield. The evolution of the orogeny has led to the development of strike-slip structures forming pull-apart basins along the North Guiana Trough. The lithostratigraphic succession of the greenstone belts is defined by:

  a lower unit of oceanic pulverizer basalts overlain by

  o mainly calc-alkaline volcanic suite including felsic to mafic members, and
o various types of sedimentary rocks such as greywacke, pelite, chert, and conglomerate.

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In Suriname, sedimentary and volcanic units of the greenstone belt are grouped into the Marowijne Supergroup which is divided itself into two formations: the Paramaka Formation and the Armina Formation. The Paramaka Formation is constituted of volcanic rocks, whereas the Armina Formation is constituted of flysch sequences represented by greywacke, mudstone, and conglomerate. The volcanic succession is associated in time and space to TTG plutonism.

In Suriname the plutonic and volcanic rocks are unconformably overlain by the upper detrital series of the Rosebel Formation which consists of arenitic quartz-rich sequences interlayered with conglomerates. This sedimentary sequence is interpreted as being deposited in the intracontinental pull-apart basins during the latest stages of the Main Transamazonian Orogeny between 2.11 Ga and 2.08 Ga. Synchronously with the formation of those basins, granitic magmatism took place in the eastern part of the Guiana Shield (Suriname, French Guiana, and Brazil).

The whole Guiana Shield has undergone prolonged chemical weathering, reflecting a humid, tropical paleo-climate that may have started as far back as the Cretaceous period. The chemical weathering has produced a laterite/saprolite profile which locally reaches up to 100 m below surface. In the Rosebel area, fresh rock can be observed around 30 m depth in valleys, where the water table is less affected by seasonal fluctuations. The thick cover of rain forest vegetation has protected the soil from erosion, and the thin soil profile is generally preserved. The chemical effects of the deep weathering include leaching of mobile constituents (alkali and alkali earths), partial leaching of SiO2 and Al2O3, formation of stable secondary minerals (clays, Fe-Ti, and Al-oxides), mobilization and partial precipitation of Fe and Mn, and concentration of resistant minerals (zircon, magnetite, and quartz).

7.2

RGM CONCESSION

The Rosebel deposits are hosted by a volcano-sedimentary sequence of the Marowijne Supergroup and by the overlying detrital sedimentary sequence of the Rosebel Formation. Five types of rocks are distinguished on the property: felsic to mafic volcanic rocks, flysch sequence, arenitic sedimentary rocks, felsic intrusion, and late diabase dykes. Economical gold mineralization has been recognized in sedimentary and volcanic rocks while the intrusion only shows rare gold occurrences and the late diabase dykes are devoid of any mineralization.

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The regional metamorphism is restricted from low-greenschist to greenschist facies. The main regional fabric varies from east-west in the Southern part of the property to WNW-ESE to the North and follows the regional tectonic. Two phases of deformation are recognized on the property. The first one has affected the older volcanic rocks only, while the second phase of deformation has affected the volcanic rocks and both sedimentary sequences. The veins show no signs of deformation and so the mineralization is interpreted as being emplaced during the latest stage of the last deformation event (Daoust et al., 2011).

Volcanic rocks are found to the north and in the southern part of the mining concession. In the southern part they surround the tonalite intrusion (Brinks intrusion), while in the northern part, up to Charmagne concession, they form bands a few kilometres thick alternating with the sedimentary rocks of the Armina Formation (Figure 7-2).

The arenitic sequence of the Rosebel Formation forms the central sedimentary basin which unconformably overlays the volcanic rocks. The whole sequence is folded into a syncline and is crosscut by several major faults. On the eastern part of the concession (near the Rosebel deposit) the rocks are intruded by three post mineralization north-south diabase dykes, pertaining to the Permo-Triassic Apatoe dyke swarm.

Three mineralized domains are found on the property: the North, Central, and South domains. The northern domain includes the J Zone and Koolhoven deposits along a trend to the north of the volcanic rocks and the Pay Caro-East and Pay Caro deposits along a trend south of the volcanic rocks. The two trends follow a WNW-ESE orientation. The central domain only includes one deposit, Rosebel, which is striking east-west. The southern domain is also striking east-west and hosts the Mayo, Roma, and Royal Hill deposits.

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7.3

SARAMACCA CONCESSION

The Saramacca gold project is underlain by metabasalt of the Paramaka Formation. Younging from southwest to northeast, the main units of the Paramaka Formation are a massive basalt overlain by a thinner amygdular basalt unit and a thick unit of pillowed basalts. Rocks have been metamorphosed to the greenschist facies and have developed an assemblage of actinolite-chlorite-epidote-plagioclase. Rare, barren, thin felsic dykes crosscut the pile.

The massive basalt is a homogeneous, green, medium-grained unit in which leucoxene sporadically develops. The true thickness of the unit is unknown, exceeding 50 m. The basalt’s northeastern contact with the amygdular unit is commonly obliterated by hydrothermal alteration.

The amygdular basalt unit is a greenish-grey to buff colour where hydrothermally altered. Quartz amygdules are generally one to three millimetres in diameter and constitute up to 5% of the rock.

The pillowed basalt is over 75 m thick and exhibits typical periodic arcuate selvages in the core. It is of a medium to dark green colour and is commonly moderately magnetic.

Some graphitic shears appear to be spatially associated to the main mineralized structure.

A review of the structural geology at the Saramacca gold deposit was undertaken by SRK to assist with geological interpretation and modelling (SRK, 2017a). The structural study focussed on the following aspects:

Reviewing available core to identify and characterize the main structures controlling gold mineralization.

   

Reviewing available oriented core to extract key information about the orientation of controlling structures and integrate the data in the geological model.

   

Defining the preferential orientation and the controls on higher grade gold mineralization and determine whether high grade sub- domains should be modelled within the existing gold domains.

   

Investigating the distribution, geometry, and kinematics of post-mineralization structures that could have displaced the gold domains.

   

Characterizing the nature, geometry, and distribution of gold-bearing breccia and vein fields to ensure that the modelled gold domains properly reflect their distribution.


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Located at the contact between the massive and pillowed basalts, the Faya Bergi fault zone is a major brittle-ductile vertical dip-slip fault zone with which gold mineralization is associated with. Typical brittle features include cataclasite, gouge, fractured zones, and striated fault slip planes (Figure 7-4) and typical ductile features include shear foliation and minor folding (Figure 7-5). Several sub-parallel minor shear zones occur on either side of the fault zone.

Mineralization at the Saramacca gold project is principally hosted within a series of north-northwest trending structures ranging between 2 m and 40 m in width over a strike length of 2.2 km, and is open along strike. Several sub-parallel structures have been identified, however, the Faya Bergi and Brokolonko structures are the primary mineralized structures over a continuous distance. The other structures are variably mineralized, though more drilling is required to test their prospectivity.

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The Faya Bergi and Brokolonko structures are related to a major brittle-ductile vertical dip-slip fault zone located at the contact between the sequence of massive and pillowed basalt along the thinner amygdular unit. Various kinematics suggest that the northeast block moved up relative to the southwest block.

Mineralization is open at depth in fresh rock and extends to the surface into the thick soft saprolite and laterite surficial layers. Mineralization is contemporaneous with brittle and ductile features and is associated with hydrothermal dolomite (veins and breccias) and pyrite, and minor arsenopyrite.

Dolomite breccias are characterized by repeated “crack/seal” and dilational infilling textures. These veins are also boudinaged and folded, forming within an active dip slip environment. Higher grade gold is typically associated with dolomite breccias and pyrite mineralization, with the best gold grades located along thick fault segments to the northwest.

The alteration pattern enclosing the fault zone shows the destruction of magnetite and the formation of leucoxene at distal ranges. Carbonate-chlorite alteration becomes more dominant with increasing proximity to the Faya Bergi fault. Within the fault zone, the protolith is destroyed by quartz-dolomite-pyrite and minor mica. The alteration footprint is commonly wider in the northeast block (pillow basalt) and can extend up to 50 m from the fault zone, while in the southwest block (amygdaloidal and massive basalts) it is observed up to 15 m to 20 m from the fault zone. The larger northeast alteration footprint may be ascribed to the presence of smaller, variably mineralized, subsidiary fault and shear zones northeast of the Faya Bergi fault.

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8

DEPOSIT TYPES

Gold mineralization in the RGM and Saramacca gold deposits is structurally controlled and exhibits similar geological, structural, and metallogenic characteristics to orogenic greenstone-hosted gold deposits as described by Robert et al. (2007). Orogenic gold deposit characteristics include:

  Complex arrays of quartz-carbonate veins with significant vertical continuity
     
  Mineralization rich in silver and arsenic with varying amounts of tungsten
     
  Gold to silver ratios greater than five
     
  Mineralization may be enriched in boron, tellurium, bismuth, and molybdenum
     
  Dominant sulphide mineral is pyrrhotite in amphibolite metamorphic settings
     
  Spatial association with regional shear zones
     
  Greenstone hosted gold deposit are characterized by:

o Combination of steeply-dipping laminated quartz-carbonate veins with arrays of shallow-dipping extension veins
     
  o Distributed along regional compressional structures
     
  o Locations at boundaries between contrasting lithologies
     
o Occurring near an unconformity at the base of conglomerate sequences (this placement is especially true for large deposits)
     
  o Universal presence of crustal-scale shear zones and faults
     
o Lithologies that commonly include Fe-rich rocks such as tholeiitic basalts and felsic intrusive porphyries

This type of deposit is found worldwide along shear zones in volcanic terranes and is characterized by quartz and quartz carbonate veins and sheeted veins primarily in dilational zones where fluid permeability was higher compared to the surrounding rocks at the time of formation. These deposits typically display a complex array of quartz-carbonate veins with significant vertical continuity. While the overall sulphide content is low, the most abundant sulphide mineral is pyrrhotite.

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9

EXPLORATION


9.1

RGM CONCESSION, EXPLORATION PROGRAM 2017-2018

The RGM concession has seen various levels of exploration work over the past 140 years. Table 9-1 summarizes some of the more recent exploration worked carried over the past 40 years.

In the last three years, an important effort of local and regional mapping was carried out to build a new regional 3D geological model (including lithology, alteration, and structures).

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TABLE 9-1     SUMMARY OF EXPLORATION WORK COMPLETED ON THE ROSEBEL GOLD MINE CONCESSION

Year Company

Type of Work

1976 Surplacer

Detailed follow-up work, involving 900 hand auger holes, 4 km of bulldozer trenches and 43 Reverse Circulation (RC) drillholes

1979 Grassalco

Carried out 1,500 hand auger holes for new resource estimate

2002 Cambior

Airborne 14,750 line-km survey including magnetic and radiometric lines, spaced 200 m apart

2005 Cambior

Deep augering and small trenches conducted by Suriname Exploration department (SurEx) at Compagnie Creek

2006 Cambior

Continuation of deep augering and small trenches conducted by Surex at Compagnie Creek

2007 IAMGOLD

Continuation of deep augering and small trenches conducted by Surex at Compagnie Creek

2008 IAMGOLD

Partial Geophysical compilation of resistivity, conductivity, and metal factor of the Rosebel deposit

2010 IAMGOLD

Two exploration trenches executed in ETR and North J-Zone

2010 IAMGOLD

Two deep auger programs performed by the Mine Exploration department (MinEx), one in West- Koolhoven area (65 holes of 10 m spacing in four lines totalling 383.7 m), and one in North Tailings Pond (six holes)

2010 IAMGOLD

MinEx performed regular grab sampling, field reconnaissance, and mapping of outcrops in the South Triangle area during the exploration drilling campaign

2010 IAMGOLD

Pit mapping performed at Koolhoven, East Pay Caro, Royal Hill, and Mayo Pits

2011 IAMGOLD

MinEx conducted pit mapping, grab samples of quartz veins and surface alluvial sampling at ETR, KH, Roma, Mayo, RB East (currently known as Rosebella), East of EPC, and Blauwe Tent

2013 IAMGOLD

MinEx conducted pit mapping, grab samples of quartz veins, and surface alluvial sampling at Rosebel pit, Mamakreek, Compagnie Creek, Spin Zone and Tailings Pond, Jzone, and West Pay Caro

2013 IAMGOLD

In West Koolhoven a total of 34 grab samples were taken of quartz veins along road cuts

2013 IAMGOLD

Spin Zone grab samples collected of quartz veins along new completed road cuts

2013 IAMGOLD

MinEx conducted three pit tests and collected 12 quartz vein grab samples in Rosebel East and six pit tests in Rosebel central area

2013 IAMGOLD

MinEx conducted a small trench in Roma-West to test the continuation of mineralization in the projected waste dump area. No significant results

2013 IAMGOLD

Detailed geological mapping was also carried out by Surex over outcrops found along exposed small scale miners areas in the Koemboe area (within the concession)

2014 IAMGOLD

MinEx conducted pit mapping, grab sampling, and pit testing in Mayo, Pay Caro, J Zone, Royal Hill South, Roma, Rosebel, NW Koolhoven, ETR, Mamakreek, Compagnie Creek, Watapat, Brinky, and the road to Mindrineti Creek

2014 IAMGOLD

Induced Polarization (IP) Survey of 11.7 km on eight lines with a spacing of 200 m was conducted by Surex at Rosebel East and West

2014 IAMGOLD

Surex conducted an AEM survey (2,775 km) covering the RGM concession, Thunder Mountain concession, and parts of Charmagne West, Charmagne, and Headley’s Reef concessions

2014 IAMGOLD

Surex conducted several IP surveys in the RGM concession including South Roma, EPC, and Rosebel

2014 IAMGOLD

Surex conducted several manual and mechanical augering programs in the RGM concession including Mamakreek, Compagnie Creek, and Koolhoven West

2015 IAMGOLD

Intense detailed pit mapping in East Pay Caro, J Zone, Rosebel, and Royal Hill to be used in further development of the pits, identifying optimal drilling directions for MinEx and RC grade control, and new geological interpretation

2015 IAMGOLD

Mapping and grab sampling of quartz veins in Mamakreek and Compagnie Creek

2015 IAMGOLD

Small shallow auger program of 66 holes at Royal Hill SE pits of SSM tailings was conducted by MinEx

2016 IAMGOLD

Intense detailed pit mapping in East Pay Caro, West Pay Caro, J Zone, Rosebel, Royal Hill, Roma, Overman, and Mayo to be used in further development of the pits, identifying optimal drilling directions for MinEx and RC grade control and update geological interpretation

2017 IAMGOLD

MinEx conducted pit mapping, grab sampling, and pit testing in Koolhoven-Jzone, West Pay Caro, and Rosebel


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9.2

SARAMACCA CONCESSION


9.2.1

GOLDEN STAR AND NEWMONT (1994 – 2010)

The Saramacca concession was formerly part of a larger grants package owned by Golden Star, formerly known as Kleine Saramacca. Other concessions of the package included Moeroekreek (often referred to as the Sarafina concession) to the northwest, and the Saramacca grant (now called Brokolonko) to the northwest of the Moeroekreek concession.

Historical regional-scale reconnaissance work was performed over an extent greater than the entire package and without consideration of the concession boundaries. The exploration work performed by Golden Star and subsequently by a joint venture between Golden Star and Newmont is summarized in Table 9-2 and shown in Figure 9-1. More drilling information is presented in Section 10.

TABLE 9-2     SUMMARY OF EXPLORATION WORK COMPLETED BY GOLDEN
STAR AND NEWMONT AT THE SARAMACCA GOLD PROJECT

  Year

Type of Work

 

Comments

Golden Star
Resources
Ltd
1994

Regional airborne magnetic and radiometric survey

Over Saramacca grant package and Rosebel area concessions

1997

Stream sediment sampling on 8 to 15 km2 drainage basin for Bulk Leach Extractable Gold (BLEG)

Identification of anomalous alluvium in slopes of Brokolonko Range

1998

Stream sediment sampling on > 6 km2 drainage basin for BLEG

2002-2005

Shallow soil sampling on 800 m by 100 m grid (locally 1,200 m by 100 m) along Brokolonko Range

Several gold anomalies highlighted, amongst them, Anomaly M, which was sampled with a smaller grid defining a 4.5 km long >100 ppb soil anomaly

2005

Deep auger sampling on 200 m by 50 m grid over Anomaly M

Definition of a 2,000 m by 500 m >200 ppb anomaly

2005

24 DD holes for 1,307.24 m

Confirmation of the existence of in situ mineralization

Golden Star –
Newmont JV
2006-2007

IP Survey over geochemical anomaly and drilled area

The initial gradient array survey defined a series of linear chargeability and resistivity features, trending roughly parallel to the ridge. Following this, several dipole-dipole survey lines were done perpendicular to these features, giving a three-dimensional view of the IP characteristics of the target area

2008

30 DD holes drilled for 3,566.27 m

Confirmation of subvertical mineralized structures with a continuity along strike (130°)

2010

36 DD holes drilled for 4,419.97 m . In total 90 DD holes have been drilled for 9,293.48 m

 

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9.2.2

IAMGOLD-RGM (2016 – 2018)

Prior to 2018, exploration work conducted by IAMGOLD-RGM on the Saramacca concession was performed by the Suriname Exploration department (SurEx) focussed on exploration work conducted outside of the Rosebel mining concession. Exploration activities in the first and second quarter of 2018 were performed by the Mine Exploration department (MinEx). The main exploration activities carried out by IAMGOLD-RGM since its involvement in the Saramacca gold project include DD and RC drilling, and some mapping.

Geological and regolith mapping was completed from January to March 2017 by SurEx, over the footprint of the Saramacca resource area. Road and drill pad construction created numerous cuts in the topography to expose the regolith and enable detailed mapping on a scale of 1:500. The northern slope of the Brokolonko Ridge area is dominated by colluvium overlying saprolite, or massive to mottle clay. The colluvium comprises of unsorted clasts of iron oxide, duricrust, indurated saprolite, and pisoliths floating in a beige clayey matrix. This colluvium layer varies in thickness from 1 m to 3.5 m and is in contact with saprolite or mottled zone. The top of the ridge is covered with discontinuous duricrust carapace which can locally reach 6 m in thickness. Large blocks of ferricrete up to 5 m in diameter sit on top of the duricrust in the northwestern portion of the area.

In 2017 and 2018 IAMGOLD-RGM completed a mapping campaign coupled with IP and Mobile Metal Ions (MMI) geophysical surveys focussed along the southern extensions of the concession where new access was being built. The mapping area is commonly covered by a very thin colluvium layer (approximately 0.5 m in thickness) and recent cuts exposed a basalt saprolite. Subvertical graphitic shears oriented southeast-northwest characterized by strong graphite and kaolinite alteration with minor quartz veining were mapped and sampled. Assay results from samples collected in the northwest of Saramacca close to the Faya-Tigri road reveal no significant intercepts.

In 2017, orientation MMI surveying was carried out along section line 1650NW to determine the MMI signature of the Saramacca ore zones for future application in adjacent exploration areas. The orientation line covers both barren and mineralized portions and was conducted at a 50 m sample pit spacing. At each pit, four samples were collected at 10 cm intervals to a maximum depth of 40 cm beneath the organic layer to establish optimum sample depth. A total of 149 samples were collected, including field duplicates.

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9.3

REGIONAL EXPLORATION

Surrounding the RGM concession are Thunder Mountain, Headley’s Reef, Charmagne, LEF, Charmagne West, Moeroekreek, and Saramacca ROEs all of which are held by RGM (Figure 9-2). RGM has been engaged in a long-term exploration effort on these exploration concessions up until 2015 when the focus of exploration work shifted to the Saramacca Gold Trend on the following concessions, where exploration activities are currently underway:

  Saramacca, acquired by RGM in 2016
     
Moeroekreek concession, which was explored under an agreement with a third party, and
     
  Brokolonko concession, acquired in 2018.

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9.3.1

THUNDER MOUNTAIN RIGHT OF EXPLORATION

The Thunder Mountain concession covers a V-shaped area that is continuous with the northern, eastern, and southern boundaries of the RGM concession. Exploration targets occur within a similar geological setting and in part, cover the extensions of the Rosebel mineralized trends.

Exploration activities completed by RGM since 2004 have included; geochemical surveys, ground magnetic surveys and IP surveys, the latter focused in the northern part of the concession. Detailed geological mapping has also been carried out over outcrops found along cut lines or exposed in small scale miner’s areas. In 1990, an airborne magnetic survey flown by Golden Star, covering the whole concession, has since been reprocessed. In 2011 another airborne magnetic survey was flown by Aeroquest over the RGM concession with partial coverage of Thunder Mountain.

In 2013, in house IP equipment has been used for surveying and this has become a systematic exploration tool.

An AEM survey (2,775 km) was completed in 2014 covering the RGM concession, Thunder Mountain concession, and parts of Charmagne West, Charmagne, and Headley’s Reef concessions. IP surveys were also completed on several prospects in Thunder Mountain and RGM concession. Geochemistry was also undertaken on these prospects utilizing contractor crews for manual augering and mechanical augering in areas of savannah.

Systematic augering surveys utilizing manual and mechanical augers were used to assess priority areas selected for their favourable geological setting and location relative to the known mineralized trends extending from the RGM concession. These priority areas are: Mamakreek, Dabikwen Drainage, Compagnie Creek, and Afobaka.

Mamakreek is on the same trend as the Koolhoven and J-Zone deposits and straddles RGM concession and Thunder Mountain concession. In 2009, 35 DD holes totalling 4,850 m and 25 RC drill holes totalling 1,675 m were completed between March and November. The majority of drilling performed was within the Thunder Mountain concession and tested known near-surface mineralization, structural targets, geochemical anomalies, and anomalous geophysical responses (magnetic and IP). Drilling identified an envelope with poorly confined, scattered quartz veins. Quartz veining generally returned low levels of gold, reducing the likelihood of resource development but mineralization remains open along strike and at depth. In 2013 and 2014, the Mine Exploration department carried out brief drilling programs in the southern part of the area where previous diamond holes were drilled (see Section 10).

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South of RGM concession, the Koemboe Creek anomaly is located near the south border of the Brinks pluton. In 2010 and 2011 this gold anomaly was drilled. In 2011, DD drilling (20 holes, 3,135 m) and RC drilling (33 holes, 1,341 m) were performed in this area. In 2012, a second phase of the DD drilling campaign was performed (21 holes, 3,043 m). Between 2012 and 2013 an additional nine holes were completed for 1,275 m. A Gemcom geological and weathering model was developed in 2013 to complete an initial resource estimate based on the 50 DD holes (7,453 m total diamond drilling). Detailed geological mapping was also carried out over outcrops found along exposed small scale miners areas. Small scale mining has increased dramatically in the Koemboe area over 2012-2013. This mining is destroying outcrops and mining saprolite where gold-bearing structures had been discovered. Surface resources have been affected. Mapping and channel sampling in small scale mine workings identified an anomalous area east of Koemboe. In 2012, three reconnaissance drill holes were completed in East Koemboe for a total of 510 m.

The Compagnie Creek prospect is located at the south-east limit of the RGM concession. In 2012, surface geological mapping and a first phase of DD drilling (13 holes, 622.5 m) were carried out. In 2013, a second phase of diamond drilling consisting of 13 holes totalling 1,326 m was completed on the Companie Creek prospect. Part of this 2013 drilling campaign included completing two holes totalling 204 m on the Rosebella prospect and an additional two holes on the Intersection target totalling 196 m.

In 2012, a DD campaign (16 holes, 4,000 m) was also performed on the eastern extension of the actual Rosebel pit, outside the RGM concession in an area known as East Rosebel.

Exploration in 2014 was completed on the Afobaka and Dabikwen prospect areas. Exploration occurred along the Royal Hill trend where it extends outside the RGM concession towards the Afobaka dam. The prospect is 8 km long and was highlighted by historical anomalous geochemistry.

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Exploration activities in 2014 included deep auger (1,325 holes for 8,610 m), IP (31 line km), RC drilling (11 holes for 1,690 m), and DD drilling (11 holes for 1,767 m).

In 2015, exploration activities focused on the West Afobaka prospect and the Dabikwen prospect, both of which are located on the Royal Hill trend, an area where significant small scale mining is being undertaken. These prospects are located on the contact of the Paramaca volcanics and sediments of the Rosebel Formation, in the vicinity of late cross cutting dykes.

Exploration activities in 2014 included deep auger (254 holes for 1,614 m), mechanical auger (75 holes for 765 m), and RC drilling 14 holes for 1,740 m).

No exploration, other than target generation activities, has been completed since 2015.

9.3.2

HEADLEY’S REEF RIGHT OF EXPLORATION

The Headley’s Reef concession lies to the south-west of the RGM concession and borders the Thunder Mountain concession to the east. Exploration activities have revealed that the northern part of the concession, covering the western extension of the mineralized trend, which hosts the Royal Hill, Roma, and Mayo deposits, is underlain by a similar geology to the RGM concession. The southern part is underlain, at least in part, by volcanic and sedimentary units of the older Paramaka Formation and the granite-gneiss units of the younger Saramacca Complex.

Exploration work carried out by RGM since 2004 has involved geochemical auger sampling and geological mapping over outcrops found along lines cut or exposed in small-scale mining areas. The Golden Star airborne geophysical survey carried out in 1990 covers the entire concession. The new airborne magnetic survey flown in 2011 by Aeroquest covers partly Headley’s Reef.

The principal targets, the Kraboe Doin “A” and “B” areas, were initially defined by anomalous stream sediment sampling results and lie close to the largest known area of small-scale mining activity located at the common boundary of Headley’s Reef and Thunder Mountain concessions. Systematic deep auger sampling and detailed geological mapping defined several targets for diamond drilling. The southern extension of the Blauwe Tent trend (from the RGM concession) and the Koemboe Creek area of Headley’s Reef (direct extensions of Koemboe Creek area of the Thunder Mountain concession and north of Kraboe Doin) are additional areas where deep auger sampling and mapping have been carried out. In 2011, at Kraboe Doin, diamond drilling (24 holes, 3,605 m) and line cutting (32 km) were performed in the Kraboe Doin “A” and “B” targets. In 2012, a single hole (130 m) was completed in the Kraboe Doin “A” target as a follow-up, in late 2013, an additional two diamond drill holes were completed In Kraboe Doin “A”, for a total of 320.4 m.

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Drilling was completed at the Saisamauw project where 2,500 m of DD drilling was completed, targeting similar geological structures as the Mayo Pit. In 2012, a total of 2,500 m in 10 holes was drilled to test this geological contact.

In 2014, satellite photography and AEM was flown over the Headley’s Reef concession.

No exploration, other than target generation activities, has been completed since 2014.

9.3.3

CHARMAGNE

The Charmagne/LEF concession includes the Overman advanced project (as part of RGM resources, thus included in more detail in Section 9 of this report). In 2010, the Regional Exploration department completed 10,387 m of DD drilling in 76 holes on this advanced project.

Following the positive results of a concept study, a program totalling 10,293 m of diamond drilling in 78 holes was completed in 2011 by the Mine Exploration department for resource development purposes. In 2011, the Regional Exploration department conducted deep augering (872 holes), line cutting, MMI geochemistry, soil sampling, field mapping, airborne magnetic survey coverage by Aeroquest, and diamond drilling (11 holes, 1,774 m) in the distant extension of the silica body hosting the gold mineralization.

In 2012, the Regional Exploration team carried out surface geochemistry, augering, and diamond drilling in Charmagne/LEF ROE. In 2012, the Mine Exploration team performed 7,258.5 m of diamond drilling, specifically on the Overman project.

In 2013, the Regional Exploration team completed two deep auger programs (306 holes, 2,320 m), trenching (4), an IP ground survey (24.95 km), and diamond drilling (5 holes, 799 m) in Central Charmagne approximately 2 km southeast of the Overman project.

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In 2014 an AEM and satellite photography survey was flown.

9.3.4

CHARMAGNE WEST

The Charmagne West concession borders the Thunder Mountain and the Charmagne concessions to the South and to the East respectively. An aeromagnetic and radiometric survey was conducted in 2011 over both Charmagne and Charmagne West concessions. SRK was commissioned to develop a lithological and structural interpretation of the data; to define key controls on the distribution of gold mineralization to aid regional exploration; and to delineate target areas for follow-up exploration. One of the identified targets, interpreted as a strained intrusive, lies within the Charmagne West concession.

In 2012, the Regional Exploration team completed a concession wide stream sediment and pan sampling program (112 samples), a deep auger campaign on the strained intrusive (1008 holes, 4,499 m), geological mapping, and an IP/Resistivity ground survey (19.8 km).

In 2013, the IP anomaly identified in 2012 was followed up by deep auger (187 holes, 1,442 m), mechanized auger (126 holes, 327 m), trenching (1), and IP/resistivity (3.5 km) programs.

In 2014, an AEM (HeliTEM) survey was completed over the area, along with a satellite image acquisition.

No other exploration, other than target generation activities, have been completed since 2015.

9.3.5

MOEROEKREEK (SARAFINA)

The Moeroekreek (Sarafina) concession borders the Saramacca and the Headley’s Reef concessions to the southeast and to the east respectively. The concession is being explored under a right of small scale exploitation owned by a third party with which IAMGOLD has an agreement to conduct exploration work. The concession had been previously explored by Golden Star.

In March 2014, IAMGOLD initiated several programs on the property, such as geochemistry, field mapping, IP surveys, trenching, and drilling.

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Deep auger and manual auger geochemical program started in 2014 along the Brokolonko ridge and was mainly concentrated near the vicinity of the historical anomalies and small scale mining pits. It was carried out on an 800 m by 50 m grid, with a subsequent infill with lines at a 400 m and then 200 m line spacing. 580 holes have been augered totalling at 4,067 m. In addition, a mechanized auger program was performed on existing roads at a 50 m distance. Also, 31.75 km of IP lines covering the Brokolonko ridge were completed in 2014.

These programs helped defining new drilling targets referred to as Puma, Ocelot, and Lynx.

In 2015 and 2016, additional intense deep augering program was carried out to expand the four main targets (Tigri, Puma, Ocelot, and Lynx). XRF and ICP analysis were conducted on 7,573 deep auger and drilling pulps for a geochemical studies and geological interpretation of main lithological units. Other programs included IP lines (completed on the Ocelot prospect) and field mapping, which was carried out on road cuts, SSM pit faces and drill pads.

Those were followed up with 28 trenches, excavated between 2014 and 2016 for a target evaluation purpose on selected deep auger and IP anomalies; the trenches exposed shear zones graded up to 46.2 g/t Au (Ocelot) and multiple quartz veins.

The 2014-2016 drilling program consisted of several phases and was focussed on four prospects:

Puma was initially tested with 10 RC holes in 2014 (1,468 m) followed by six RC holes (750 m) and six DD holes (969 m) in 2015;
     
Tigri was tested by 11 DD holes (1,614 m) in 2014, followed by three DD holes (501 m) and 10 RC holes (1,470 m) in 2015;
     
  Lynx was drilled in 2014 with 10 RC holes (1,432 m);
     
Ocelot was the most intensively drilled target, with 20 DD holes in 2015 (2,470.5 m) and 19 DD holes in 2016 (2,700 m).

The drilling program returned encouraging intersects, though lacking continuity.

In 2017- 2018, the exploration activity consisted of MMI surveys around and between the four main prospects, processing of historic airborne gamma-ray spectrometry and magnetometry data obtained after the 1998 survey over the region, and reinterpretation of geological and geochemical data. Based on that information, targets for the upcoming 2018-2019 program have been selected, and the initial phase of a new drilling program is currently underway.

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Table 9-3 summarizes work done by IAMGOLD on the Sarafina concession GMD No. 233/14 since its involvement in the project area.

TABLE 9-3    MAIN EXPLORATION ACTIVITY STATISTICS PER PERIOD OF ACTIVITY

Sarafina Concession IAMGOLD–RGM  IAMGOLD–RGM   IAMGOLD–RGM  IAMGOLD–RGM
GMD No 233/14 Mar 6, 2014 to Feb 6, 2015 to Feb 6, 2016 to Feb 6, 2017 to
  Feb 5, 2015 Feb 5, 2016 Feb 5, 2017 Aug 31, 2018
Number of grab samples 129 245+ 332+ -
Number of channel samples - - 222 -
Geological Reconnaissance Complete Complete Complete -
Geology Mapping Complete In progress In progress -
Structural Interpretation - - In progress In progress
Ground IP Survey (km) 31.75 - 7.825 -
MMI (number of samples) - - - 372
Line cutting (in km) 37 54 10 23
Deep Auger (number of holes) 512 999 76 -
Deep Auger (number of samples) 3,639 6,346 259 -
Mechanized Auger (number of holes/ samples) 178 / 1263 - - -
XRF Analyses 2,505 7,573 - -
Trenches (quantity / total length, m) - - 28 / 1,440 -
RC drilling (number of holes / m) 24 / 3,477 15 / 2,220 0 -
Diamond drilling (number of holes / m) 11 / 1,614 21 / 3,310 19 / 2,700 -

9.3.6

BROKOLONKO

The Brokolonko property was acquired in February 2018 due to its high exploration potential. The property is characterized with direct signs of gold mineralization (long term alluvial and SSM operations, finding of gold nuggets, historic shafts), geochemical anomalies (soil, shallow and deep auger) after historic exploration, completed by Gold Star and Golden Star-Newmont JV, and positive results from an orientation BLEG survey.

The IAMGOLD-RGM exploration program commenced in February 2018. It includes: processing and re-interpretation of an historic (1998) airborne gamma-ray spectrometry and magnetometry survey, geology mapping on SSM pits, and a verification of an historic deep auger geochemical survey on the priority target area (Pompoekompoe). Based on positive results from this work, a drill program was carried out on the Pompoekompoe prospect, consisting of 20 RC holes at 2,942 m and 25 DD holes at 4,109 m. The program returned narrow low grade mineralization (from 0.4 to 2.8 g/t Au) in a complex, metamorphic environment cut by multiple felsic and intermediate intrusions; only minor amounts of tectonites, graphitic shear, and quartz material was observed in the holes. Two high grade intersects, up to 88.55 g/t Au over a 1.1 m interval were recovered on the outermost southeast drill line, keeping the mineralization open in both directions. Follow-up on that is considered along with exploration on other targets outside of the Pompoekompoe area, with additional geochemical, mapping, and drilling programs planned for years 2019-2020.

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Table 9-4 summarizes the work carried out on the Brokolonko concession GMD No. 1157/17 by IAMGOLD-RGM since the involvement in the project area.

TABLE 9-4     STATISTICS OF BROKOLONKO CONCESSION EXPLORATION
ACTIVITY BY IAMGOLD-RGM

Brokolonko Concession IAMGOLD – RGM
GMD No. 1157/17 February-August 2018
Number of grab samples 149
Number of channel samples 18
Geological Reconnaissance In progress
Geology Mapping In progress
Structural Interpretation In progress
Geophysical Data Interpretation In progress
Deep Auger (number of holes / m / samples) 37 / 290 /192
RC Drilling (number of holes / m) 20 / 2,942
DD Drilling (number of holes / m) 25 / 4,109

9.3.7

SARAMACCA

Exploration activity on the Saramacca concession has continued outside of the resource area. It is focused on northwest striking zones parallel to the Faya Bregi fault and characterized with elevated Au values after MMI. Other exploration targets are: potential contact with a pyroclastic unit situated northeast of the Faya Bergi fault and potential continuation of the Saramacca mineralization along the fault on its southeast and northwest extensions. The targets are characterized with magnetic features similar to those on the Saramacca deposit, identified after an unsupervised classification of an historic airborne magnetometry survey.

The exploration activity includes: processing of historic 1998 airborne magnetometry and gamma-ray spectrometry surveys, geochemical research, MMI survey on the target areas and infill lines, and diamond drilling on the northwest extension of the Faya Bergi fault, outside of the resources area. The diamond drilling commenced in August 2018 and consisted of eight DD holes totalling 1,410 m as of Sep 01, 2018 which have identified weak mineralization, which however, could be a possible extension of the Saramacca resources.

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The summary of the above-described exploration activity, which was mostly commenced in 2018 and currently ongoing, is found in the Table 9-5.

TABLE 9-5     STATISTICS OF EXPLORATION ACTIVITY BY IAMGOLD-RGM ON
THE SARAMACCA CONCESSION OUTSIDE OF THE SARAMACCA
DEVELOPMENT AREA

Saramacca Concession  
(outside of the Saramacca Development IAMGOLD – RGM
area)  
  December 2017-
GMD No. 5167/16 August 2018
Number of grab samples 59
Number of channel samples 18
Geological Reconnaissance In progress
Geology Mapping In progress
Structural Interpretation In progress
Geophysical Data Interpretation In progress
MMI (number of m / samples) 11,000 /1,272
RC Drilling (number of holes / m) 8 / 1,410

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10

DRILLING


10.1

INTRODUCTION


10.1.1

RGM CONCESSION

Intensive diamond drilling programs were carried out on the RGM concession between 1992 and 1997. Between 1998 and 2000, the Rosebel project remained on care and maintenance and no additional drilling was undertaken. Drilling resumed in 2002 with the objective of sterilizing the waste dump at Pay Caro and with additional geotechnical drilling at the mill site and tailings pond. Exploration/definition drilling resumed in 2004. Table 10-1 lists the DD drilling and RC drilling quantities by year from 2004 to 2018. Since 2004, a total of 763,811 m of DD drilling and 62,507 m of RC drilling has been carried out. Since 2018, the same drilling procedure is used at both the RGM and Saramacca projects.

TABLE 10-1     2004 – 2018 RGM DIAMOND DRILLING AND REVERSE
CIRCULATION DRILLING

Year DD (m) RC (m)*
2004 33,803 -
2005 54,854 -
2006 64,553 -
2007 52,914 -
2008 64,758 -
2009 85,843 -
2010 94,537 -
2011 88,706 -
2012 104,061 -
2013 65,557 -
2014 14,488 13,566
2015 12,229 6,234
2016 19,066 10,762
2017 8,442 31,945
2018 - -
Total 763,811 62,507

*excluding grade control drilling

Several types of drill rigs were used in the past. Major Drilling International Inc. (Major Drilling) has been the drilling contractor on the Rosebel property since 2004. Major Drilling uses UDR-200D track mounted rigs. Production is generally 50 m per shift at an average recovery rate higher than 90%. Since 2017, a RC rig has been used by Major Drilling for expansion and exploration drilling. Others types of drilling were used in the past mostly for geochemical exploration work, including: Auger and RC Scout. During 2017, one diamond drill rig and one RC drill rig were running, for alternating periods of time.

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10.1.2

PLANNING

The drill planning takes into consideration four different purposes; infill/development, expansion, exploration, and condemnation.

The infill or development drilling is targeting a better definition of the resources or reserves within the whittle shells or pit design. The spacing for infill drilling is usually 50 m or 25 m, depending on the level of geological comprehension of the deposits or on the geological complexities related to the mineralization.

The expansion and/or exploration drilling are targeting the extension of mineralization outside the pit designs, either laterally or at depth. Some exploration/reconnaissance drilling also occurs in new or less advanced exploration areas; in that case there are no reserves defined and the drilling is based on preliminary geological interpretation rather than on extension of known ore zones. There is no particular spacing in that case, as the drilling can be tight in order to make a follow up on good results, or it can be more spread out in order to cover a larger area.

The condemnation drilling is carried out to ensure that there is no mineralization where the waste dumps are planned to be located. The spacing is approximately 150 m to 200 m using staggered patterns or continuous fences, although sometimes the condemnation drilling can be useful in getting a better comprehension of the geology surrounding the deposits, and in such a situation the drilling pattern may differ.

Even though in the past three years the amount of drilling has decreased, most of the pits are being drilled every year with respect to the three main purposes presented above. The distribution of metres and targets for each pit depends on the amount of historical drilling in each pit, on the infill needed according to the geological complexity, and the potential at depth and laterally, or the open exploration.

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10.1.3

METHODOLOGY – DIAMOND DRILLING

Before drilling a hole, the field technician’s spot the planned hole by using old drill holes, as a reference, and a hand-held GPS. The Minex field technicians survey the planned locations using a ground-based high-precision Leica GPS unit. Under supervision, the contractor sets the diamond drill onto the collar and the field technician aligns the drill with the help of the front sights.

Holes are drilled using HQ size wireline equipment in saprolite, usually reducing to NQ size in transitional to hard rock. The recovery being usually very good (>90%), drill holes with unacceptably low recovery in mineralized zones are re-drilled until reaching an acceptable level of representativeness (minimum of 65% on short intervals and an average of 75-80%). Core recovery in saprolite and transition material is improved by using polymer additives combined with high concentrations of bentonite.

Drill-hole surveys are completed using Flex-IT/Reflex singleshot/multishot instrument which can also provide magnetometric data down the length of the hole. A single shot (one measurement) is always taken at a depth of 10 m to 15 m to make sure that the orientation and the dip are in line with the planned hole. If the deviation is higher (as decided by the geologist) the hole is stopped and re-started a couple of metres next to the first hole. For drill holes longer than about 150 m, a single shot is also taken every 50 m, while drilling, to ensure that the hole will meet the target. When a hole is completed, a multi shot survey is carried out starting at the bottom of the hole, by taking a measurement every 3 m. For the interval of survey taken inside the magnetic casing (generally less than 50 m), the trace is estimated from the last measurement before entering the casing and on the single-shot measurement that was taken after the first 15 m of the hole.

When the diamond drill leaves the location, the drill hole collar is identified by a 75 mm by 75 mm wood post that is placed in the hole left by the steel rods and the hole is re-surveyed. The sump containing the cutting rejects generated by the drilling processes is closed and the pad is leveled with a dozer.

Core is packed in corrugated plastic boxes at the drill site, prior to being transported to the core shack. At the core shack, the core is washed to remove the drilling fluids and to expose structures in the soft saprolite material. Geotechnical logging is carried out afterwards by recording the core recovery, rock quality designation (RQD), rock hardness, and fracture density. The core is then logged in detail (lithology, alteration, veins, etc.) and samples are identified. The drill holes are sampled continuously from top to bottom of the hole with a length generally between 1.0 m and 1.5 m. Pictures of the core are systematically taken before splitting and then the samplers start splitting the core and sampling the intervals. The second half of the core is always kept in the core racks for reference and/or further testing.

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10.1.4

METHODOLOGY – REVERSE CIRCULATION DRILLING

RC drilling follows similar procedure as for diamond drilling. Before executing a hole, the field technician spots the planned hole by using existing drill holes, as reference, and a hand GPS. The rig operator sets the RC drill onto the collar and the field technician aligns the drill with the help of the front sights. Holes are drilled using a 114 mm or 136 mm rod size. The recovery is variable and tends to increase with the depth. The RC rig can drill holes up to 150 m using a compressor to collect good quality of dry samples. Down holes surveys are taken at the end of the hole.

When the RC rig leaves the location, a wooden stick with flagging tape is used to identify the hole. The holes are surveyed with a Leica GPS. As the rig is not using water, no sumps are required.

The cuttings are going through a cyclone, a rotary splitter, and two plastic bags placed at the end for sampling. Samples are taken every 2 m and generally consist of two 5 kg bags: one bag for assaying and the other one for logging the samples and as a field duplicate and/or for re-assay. A small amount of the logging sample bag is placed on the logging table where the geologist describes the material (alteration, lithology, presence of quartz, pyrite). Pictures of cuttings are taken before placing the material in chip trays. If no picture of the cutting is taken, a picture of the chip tray is taken instead. For each interval, the sample bag for assaying is sent to the laboratory for analysis, the other bag being kept at the core shack until results are obtained and no further sampling is required.

10.1.5

RGM CONCESSION DRILLING PROGRAM 2018

In 2018, no diamond drilling was carried out on the property.

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A total of 184,450 m of RC grade control drilling was performed since the last resource update (NI43-101, June 2017) and has been used in the present resource estimate. The database was closed as of January 15, 2018 for the RGM concession.

10.2

SARAMACCA CONCESSION DRILLING

Golden Star, and later as a joint venture with Newmont, conducted three phases of DD drilling totalling 90 holes (9,293 m) between 2002 and 2010 on the Saramacca concession.

Exploration activities, consisting mainly of DD and RC drilling, resumed in October 2016 after RGM signed a Letter of Agreement with the Republic of Suriname to acquire the rights to the Saramacca gold property. In total, 442 DD holes (85,446 m) and 41 RC holes (4,986 m) have been completed on the Saramacca mineralized zone, to date, with a few holes completed on the peripheral deep auger or IP anomalies. A breakdown of the drilling, by period, and by company, up to May 22, 2018 is presented in Table 10-2.

TABLE 10-2     STATISTICS OF DRILLING CONDUCTED ON THE SARAMACCA
GOLD PROJECT TO MAY 2018

  Goldstar Goldstar/Newmont Goldstar/Newmont IAMGOLD-RGM Total
Hole Type 2002-2005 2006-2008 2009-2010 SurEx 2016-2018  MinEx 2018  
  No. (m) No. (m) No. (m) No. (m) No. (m) No. (m)
Undefined 157 1,160 241 1,905 - - - - - - 398 3,065
                         
DD 24 1,307 30 3,566 36 4,420 286 60,701 66 15,472 442 85,466
                         
RC - - - - - - 41 4,986 - - 41 4,986

10.2.1

GOLDEN STAR AND GOLDEN STAR-NEWMONT JV (2005 – 2010)

An initial program of 24 shallow DD holes totalling 1,307.2 m was carried out on soil anomaly M during 2005 by Golden Star (Figure 10-1). Boreholes were 50 to 70 m in vertical depth and did not exceed 81 m in drilled depth. Drill orientations were 215°E (grid south), except for MA020 and MA021 which were at 035° (grid north) and MA023 and MA024 which were at 250.5° . Borehole inclinations were -45° except for MA001, MA002, and MA022 which were at -55°, and MA023 and MA024 which were at -50°. Several DD holes intersected mineralized shear zones.

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Following geological mapping and an intensive deep auger program, a second phase of DD drilling was carried out from May to November 2008 under the joint venture with Newmont (Figure 10-1). A set of 30 DD holes totalling 3,566.3 m tested the strike and depth extension of the mineralized shears encountered in previous boreholes, the main IP anomalies, and other geochemical targets on the Saramacca property. The deepest borehole drilled was 200.8 m. Canadian-owned, and Suriname-based, SureCore Portable Diamond Drilling was contracted to execute the drilling activities.

Newmont performed a third phase of DD drilling comprising 36 holes totaling 4,420 m between May and November 2010 covering the extent of the mineralized footprint (Figure 10-1). Drill orientations were 215°E (grid south), except for GMDH-033 and GMDH-034 which were at 035° (grid north). Borehole inclinations were systematically -50°. The maximum borehole depth was 198 m, while the average borehole depth was 123 m. Drilling included three short boreholes (GMDH-051 to GMDH-054) that were less than 13.5 m deep to collect duricrust samples for metallurgical tests. SureCore Portable Diamond Drilling was contracted to execute the drilling activities.

Although geological and assay data were available in the data package provided by the Republic of Suriname, there is no documentation on the drilling and sampling processes.

10.2.2

IAMGOLD-RGM (2016 – 2018)

IAMGOLD-RGM drilled 180 DD holes totalling 34,225 m and 37 RC holes totalling 4,506 m in a two-phase drilling program executed between October 2016 and April 2017.

Included in the first phase of drilling, IAMGOLD-RGM twinned 17 of the 90 historical boreholes with DD holes as part of a due diligence process from October to December 2016. The program aimed to expand the mineralized footprint by testing the continuity along strike at a 50 m by 100 m spacing.

From January to April 2017, IAMGOLD-RGM followed up on 2016 drilling results and initiated an infill DD drilling program at a 50 m by 50 m spacing, with focus on delineating a potential saprolite resource. One additional historical borehole was twinned to ensure a good spatial distribution of IAMGOLD-RGM boreholes across the mineralized footprint.

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IAMGOLD-RGM has drilled an additional 176 DD holes for 43,397 m and four RC holes for 480 m since the maiden Mineral Resource model was disclosed publicly by IAMGOLD-RGM in a news release dated September 5, 2017 (Table 10-3 and Figure 10-1. The database was closed on May 31, 2018 for the Saramacca concession.

TABLE 10-3     SUMMARY OF DRILLING PERFORMED BY IAMGOLD-RGM
 BETWEEN JULY 2017 AND MAY 2018

Borehole Type
SurEx MinEx Total
No. (m) No. (m) No. (m)
DD 110 27,925 66 15,472 176 43,397
RC 4 480 - - 4 480
Total 104 19,128 66 15,472 217 38,731

10.2.3

DRILLING PROCEDURES AND APPROACH


10.2.3.1

GOLDEN STAR AND NEWMONT (2005 – 2016)

IAMGOLD-RGM did not receive information from the Republic of Suriname regarding the drilling procedures, methodology, and approach historically used by Golden Star and Newmont. SureCore Portable Diamond Drilling was contracted by Golden Star and Newmont for the 2008 and 2010 drilling programs.

10.2.3.2

IAMGOLD-RGM SUREX (OCTOBER 2016 – DECEMBER 2017)

All DD drilling was performed by Major Drilling using three UDR 200D track-mounted drill rigs. RC drilling was contracted to FTE Forage, who used one Schramm T450 RC drill rig. An ancillary support of Hurricane B6 booster and Sullair 1,350 cubic feet per minute (cfm) at 350 pounds per square inch (psi) or 1,100 cfm at 500 psi compressors was added to push off groundwater. The same procedure as for DD drilling is implemented during the pre-drilling, rig set-up, and post-drilling stages.

Borehole azimuth was typically 215°, apart from a few being scissor holes designed at 035° to confirm the width or dip of the mineralized zone, test the footwall at higher elevation, and/or circumvent areas with poor ground conditions. Boreholes were generally drilled at -50° with some between -47° and -55°. All DD holes were drilled with HQ core rods to penetrate a few metres into fresh rock. When boreholes reached solid fresh rock, they were downsized to NQ until the end of hole. DD hole length varied from 23.5 m to 483 m. RC hole diameter was 140 mm, with an average length of 121.6 m and a maximum length of 150 m.

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Prior to building drilling pads, proposed boreholes were located by hand-held GPS. In October and November 2016, boreholes were located by IAMGOLD-RGM technicians with a hand-held Garmin GPS. Starting in November 2016, a surveyor using a total station was contracted to locate all boreholes. IAMGOLD-RGM uses UTM coordinates set in Zone 21N, WGS 1984.

An inventory of trees to be cut is completed before any earthwork is initiated. Once access and pads are completed, a pre-drilling inspection is signed off for every borehole by a representative from IAMGOLD-RGM and a Major Drilling foreman. When approved, IAMGOLD’s technicians install three front sights for the rig to align along the planned azimuth. The drill rig is mobilized to the pad under the supervision of a Major Drilling foreman, and alignment is done under the supervision of IAMGOLD-RGM technicians. Once the rig is set up, the inclination of the mast is measured by a clinometer and drilling can commence.

Down hole surveys are done using a Reflex EZ-TRAC, taking single and multi-shot readings starting at 20 m, and every 50 m thereafter until the borehole is terminated by the geologist. When drilling is complete, multi-shot readings are taken every 3 m as the rods are pulled out. Down hole surveys are downloaded from the Reflex EZ-TRAC to a laptop at the Saramacca camp and the file is imported directly into the main database. From April 6 to 19, 2017, the Reflex EZ-TRAC became defective. IAMGOLD-RGM resorted to using a Tropari to perform the down hole surveys of the 18 boreholes drilled during this period.

Once a borehole is complete, a capped PVC pipe is inserted into the collar. The borehole ID is written with permanent marker on the PVC pipes and an aluminum tag engraved with the borehole ID is attached to the PVC. Contracted professional surveyors of CM-Engineering from Paramaribo, Suriname determine the final coordinates of the collar using a Total Station and the coordinates are sent to the database manager for import. At the end of the drilling campaign, 20 boreholes were re-surveyed by the same surveyor as part of validation using Differential GPS (DGPS).

Core orientation using a Reflex ACTII tool was done on 40 DD holes. The orientation point is reflected on the bottom of the core by a mark and an extended line on the side emanating from the orientation mark at the bottom. To begin measurements of structural data, the orientation mark is extended over the core, where applicable, with arrows pointing down-hole using a red china marker. Core orientation measurement is mostly done by a protractor-ruler and a wrap-around protractor. Some boreholes were measured using Reflex IQLOGGER in March and April 2017, as a first trial to test this technology.

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Throughout the drilling campaign, IAMGOLD-RGM staff continuously monitored the different facets of drilling to ensure adherence to health and safety, environmental and drilling protocols of the company.

All geological logging including lithology, alteration, mineralization, and down hole structure was performed by IAMGOLD-RGM geologists. Data entry was done directly in CoreLogger (Gems module) using Panasonic Toughbooks. CoreLogger includes some validation tools to prevent nested intervals, intervals deeper than the end of a hole and duplicate sample numbers.

All digital data generated is stored in RGM’s servers at the mine site.

10.2.3.3

IAMGOLD-RGM MINEX (JANUARY 2018 – MAY 2018)

Drilling procedures used by IAMGOLD-RGM MinEx department largely mirror that of SurEx with few minor differences.

All diamond drilling was performed by Major Drilling using UDR 200D track-mounted drill rigs with borehole azimuths typically 215°, apart from a few being scissor holes designed at 035°. Boreholes were generally drilled at -50° with some between -47° and -55°. DD hole length varied from 75 m to 453 m.

Prior to building drilling pads, the MinEx field technicians spot the hole with the assistance of older drill holes as reference, where available, and a ground-based high-precision Leica GPS unit. Drill alignment is performed under the supervision of the field technician with the help of front sights.

Core recovery is usually very good, however, where recovery is less than 65% to 75% in mineralized zones, the hole is re-drilled until the recovery is considered acceptable. Polymer additives, combined with high concentrations of bentonite, are occasionally used in the saprolite and transition material zones to increase core recovery.

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Down hole surveys are performed using Flex-IT single-shot and Reflex multi-shot instruments. Single-shots are taken at a depth of 10 to 15 m and at an interval of 50 m for boreholes longer than 150 m. Upon completion of the borehole, a multi-shot survey is carried out for the entire length of the hole, starting at the bottom and taken at intervals of 3 m.

Once a borehole is complete, a 75 mm by 75 mm wood post is placed into the collar and the collar location is resurveyed. Core is packed in plastic core trays at the drill site.

10.2.4

CORE SAMPLING METHOD AND APPROACH


10.2.4.1

IAMGOLD-RGM SUREX (2005 – 2010)

IAMGOLD-RGM did not receive information from the Republic of Suriname regarding the sampling method and approach historically used by Golden Star and Newmont.

10.2.4.2

IAMGOLD-RGM SUREX (OCTOBER 2016 – DECEMBER 2017)

Core Drilling

IAMGOLD-RGM SurEx implements standard operating procedures (SOP) of all sampling methods strictly followed by its staff and personnel. These procedures are reviewed on a regular basis dependent on site conditions and other specific requirements. All logging and sample information is stored in a secure database customized for IAMGOLD by GEMCOM.

Core boxes are brought from the drill pads to the Saramacca exploration camp by IAMGOLD-RGM technicians on a daily basis. Geotechnical and geological logging, as well as the marking of all sampling intervals, is done at the Saramacca camp by IAMGOLD-RGM geotechnicians and geologists. Core boxes are then transported to the RGM mine site for splitting and sampling of half core. Core shack leaders insert control samples, as per the geologists’ instructions, and prepare shipments to the primary assay laboratory, Filab Suriname N.V. (Filab) in Paramaribo. A chain of custody (COC) form is signed off at each step by the recipient and always accompanies the core.

Sampling interval ranges from 0.5 m to 1.5 m, however, in rare cases where core recovery is poor, the interval is extended to enclose fixed metre marks. Visual geological indicators, such as changes in lithology, weathering, alteration, mineralization and structure, and changes in hole diameter are taken into consideration in the identification of sampling boundaries. Core is entirely sampled from top to bottom. The sampling procedure is as follows:

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At the Saramacca exploration camp:

Core is reassembled and cleaned, as needed, and orientation lines are drawn by the geologist or geotechnicians with arrows along the line pointing downhole.

   

Geotechnical logging is completed by the geotechnicians, who records core recovery, hardness of the core, RQD, joints, fractures, and the weathering facies into GemsLogger software using a laptop. Meter marks are placed on the side of the core box.

   

Geological logging is performed by IAMGOLD-RGM geologists who verify the geotechnical logging, mark the sampling intervals with a red china marker, assign the sample number, and insert a sample tag at the end of each sampling interval. A vertical line is drawn with a red china marker on the side of the core box at sample boundaries with two arrows on each side pointing away from the line to indicate the beginning and end of a sample interval. In fresh rock, the same markings are done additionally on the core.

   

A black cutting line is drawn along the core and perpendicular to the main fabric by the geologist or technicians to delineate two symmetrical halves. This line serves as a guide for core splitting at the RGM mine site.

   

Where core orientation is available, the core is split along the orientation line; the orientation being preserved by the arrows along the line pointing downhole.

   

A sampling log is prepared by IAMGOLD-RGM geologists with required control samples (blanks and certified reference materials, CRM) as per quality assurance and quality control procedure. For the beginning of every hole, a rock blank is inserted. Then, CRM and blanks are inserted alternately every 10 samples.

   

Location of specific gravity (SG) determination samples are marked by blue flagging tape tagged on the side of the core tray divider, on which the geologist writes the FROM and TO of the SG sample to later be collected at the RGM mine site.

   

Preliminary core photographs of all core boxes are taken before they are transported to the RGM mine site. Boxes are loaded onto a truck owned by Vonkel, a long-term contractor who also provides field work services. The chain of custody accompanies the core boxes and is signed off at each step from the drill pad to the final delivery to the laboratory.

   

The completed digital geological and geotechnical logs are then sent through email to the database manager to be imported into the database.

At the RGM mine site:

Sampling is carried out by IAMGOLD-RGM samplers and geotechnicians under the supervision of IAMGOLD-RGM geologists and core shack supervisors who insert control samples and prepare shipment to the laboratory.

   

 

Once at the RGM mine site core shack, core boxes are sorted on logging tables.

   

Photographs of wet and dry core with inserted sample tags are taken of every core box prior to cutting.


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A machete is used to cut soft and saprolite rock in two symmetrical halves while a diamond core saw is employed for hard rock. Core is halved along cutting lines or orientation lines previously drawn at the Saramacca camp.
   

Half core is consistently collected from one side and put into a plastic sample bag with the sample ID marked and corresponding sample tag attached to bag.

   

Wood blocks are inserted in core trays at one metre intervals to secure the position of core in the boxes

   

SG samples, previously identified in core trays by blue flagging tape, are collected (10 to 20 cm of half-core) and a sample tag with a unique SG sample ID is tagged to the core tray where the sample was taken. The core shack leader writes a list of all SG samples taken with their sample ID and from and to values. The list is entered in the database by either the geologist who logged the hole or the database manager. Note that SG samples are collected after assay samples are taken to ensure entire intervals are assayed and there is no gap where an SG sample was collected.

   

Using the sampling list provided by IAMGOLD-RGM geologists, the core shack leader prepares control samples (blanks and CRM) to be inserted with core samples and takes a photograph of the control samples with their sample tags attached. The core shack leader then erases the manufacturer’s labels from the aluminum foil sachets and places tagged control samples in individually labeled sample bags.

   

 

Control samples are sequentially inserted amongst samples by the core shack leader.

   

Samples are packed in groups of four in rice bags labelled with the Company name (IAMGOLD), the sample number interval, the internal project code number, total number of samples in the bag, and the rice bag number.

   

The core shack leader prepares one submittal form per borehole so that one submittal contains only one complete borehole and then signs the chain of custody form.

   

Rice bags and accompanying submittal and chain of custody forms are transported to Filab by a truck owned and operated by Vonkel.

   

The closed core boxes are piled chronologically, per hole, on a wooden pallet and kept for future reference.

Reverse Circulation Drilling

Sampling is supervised by an IAMGOLD-RGM geologist or technician at the drill site. FTE Forage drilling personnel collect the samples from the Metzke cyclone splitter, while IAMGOLD-RGM personnel are responsible for further handling of the samples including weighing, tagging, and logging using GemsLogger on a laptop or tablet. All further sample handling in preparation for shipment to Filab is done at Saramacca camp.

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At the drilling site:

IAMGOLD-RGM’s technician and/or geologist ensures that the drill crew has all necessary material required to start drilling including pre-labelled sample bags (clearly stating only the hole number and sample interval) and nylon cable ties or flagging tape.

   

The drill crew must level the cyclone splitter before drilling to ensure drill cutting distribution between the four chutes remains constant.

   

Three samples are collected from the cyclone splitter per two- metre interval, as shown in Figure 10- 2.

   

The sample distribution in the cyclone splitter is arranged so that the assay sample weighs approximately three kilograms, while the remaining drill cuttings are collected as back-up sample.

   

The samples are collected by the drill crew with utmost care to avoid contamination. The assay and back-up samples are collected continuously from the first and second chute, and the third chute is used every 25 samples to collect a field duplicate.

   

The assay samples are weighed, tagged, and logged at the drill site (logged if a geologist is present at the drill site). A representative scoop of sample is taken from the sample bag and placed in a chip tray for future reference.

   

The back-up samples are tied, sorted in sequence with the sample bag opening folded down, covered with a tarpaulin, and left on the drill pad. Once assay results are received and quality assurance and quality control procedures are completed, the decision can be made to store or discard the back-up samples.

   

The cyclone splitter is cleaned before drilling a new hole and at each rod change to minimize contamination.

   

 

Assay samples are transported to the Saramacca camp by the IAMGOLD-RGM crew.

At the Saramacca camp:

The samples are sorted in sequence. Irregularities, such as missing samples, are reported to the IAMGOLD-RGM geologist responsible for RC drilling.
     
If not already done in the field, the geologist logs the drill cuttings accordingly, paying attention to weathering, alteration, texture, structure, mineralization, and veining. Sample weight and sample numbers are entered into GemsLogger.
     
  Control samples are inserted into the sequence by the geologist.
     
  A photo of the chip trays for each borehole is taken for future reference.
     
  Sample tags are assigned by the geologist.
     
Sample bags are placed in rice bags. The sample number intervals and total number of samples in that bag are written on the rice bag.
     
Rice bags are shipped along with accompanying submittal and chain of custody forms to Filab by a truck owned and operated by Vonkel.

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FIGURE 10-2     REVERSE CIRCULATION DRILLING SAMPLE FLOWCHART

Sample Identification

Borehole identification codes comprise four parts: the project ID (SM for Saramacca), the type of drilling (DD for core drilling or RC for reverse circulation drilling), the year (16 or 17) and a sequential sample number starting at 001 for the first DD hole drilled in 2016 to 180 for the last borehole drilled in 2017, or 037 for the last RC hole drilled. For example, hole SMDD17-101 was drilled on the Saramacca project as a DD hole drilled in 2017 and is the 101st DD hole drilled by IAMGOLD-RGM since the beginning of the drilling program.

Sample identification codes consists of only one unique sequential number comprising seven digits. For example, #1060615.

All digital data associated with sampling is stored on the Suriname Exploration computer servers at the RGM mine site.

10.2.4.3 IAMGOLD-RGM MINEX (JANUARY 2018 – MAY 2018)

Core Drilling

Core processing and logging procedures mirror that of IAMGOLD-RGM SurEx department.

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Sample Identification

Borehole identification codes comprise three parts: the project ID (SM for Saramacca), the type of drilling (D for core drilling) and a sequential drill hole number starting at 0001 for the first borehole drilled in 2018 to 0020 for the last borehole drilled in May 2018.

Similar to SurEx sampling protocol, sample identification codes consist of only one unique sequential number comprising seven digits.

All digital data associated with sampling is stored on the Suriname Exploration computer servers at the RGM mine site.

10.2.5

SPECIFIC GRAVITY

A total of 4,776 samples were sent to IAMGOLD’s Rosebel Gold Mine site laboratory for SG determination at Saramacca. SG samples comprise segments of 10 to 20 cm of half core deemed representative of their respective unit. Samples are typically collected every 10 m in soft oxidized material down to the transition zone, and thereafter every 25 m in fresh rock. The frequency may locally increase to cover rapid changes in lithology to ensure all lithotypes are sampled.

SG samples were collected from the top to the bottom of each DD hole in both mineralized and barren material. Soft samples are wrapped in plastic film and the wrapped sample with a tag is then put inside a thick paper sachet identified with a sample tag. Fresh, hard samples are not required to be wrapped.

SG is determined by the gravimetric method, where the material is covered in a paraffin wax coat and weighed in air and then suspended in water.

Once SG determination is completed, the laboratory returns the samples, which are then put back in their original core boxes. Results are transmitted electronically and entered in the database by the database manager.

As part of the quality assurance and quality control procedure, 147 samples were sent to ALS Mineral (ALS) in Vancouver (secondary laboratory) for verification in 2017.

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SG sample identification codes comprise five parts: The prefix SG-, the project ID (SM for Saramacca), the type of drilling (DD for core drilling), the year, and a sequential sample number starting at 001 for the first SG sample collected in 2016. For example, SG-SMDD17-2004 is a SG sample collected in 2017 from a core borehole drilled at Saramacca and is the 2,004th SG sample collected by IAMGOLD-RGM since the beginning of the drilling program.

10.2.6

SRK COMMENTS

SRK is of the opinion that the drilling and sampling procedures adopted at Saramacca by IAMGOLD-RGM are consistent with generally recognized industry best practices. The applied drill pattern is sufficiently dense to interpret the geometry and the boundaries of the gold mineralization with confidence. The core samples were collected by competent personnel using procedures meeting generally accepted industry best practices. The sampling was undertaken or supervised by qualified IAMGOLD-RGM geologists. SRK concludes that the samples are representative of the source materials and there is no evidence that the sampling process introduced a bias.

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11  SAMPLE PREPARATION, ANALYSES AND SECURITY

In 2018, all RGM samples (RC grade control) were analyzed using the Pulverize and Leach (PAL) procedure, and all the Saramacca samples (DDH) were analyzed using the Fire Assay (FA) procedure.

In the IAMGOLD’s and SRK’s opinion, the sample preparation, analysis, and security procedures at RGM and Saramacca are adequate for use in the estimation of Mineral Resources.

11.1

RGM CONCESSION


11.1.1

SAMPLE PREPARATION


11.1.1.1

RGM SAMPLE PREPARATION FOR FIRE ASSAY

The whole samples (4 kg) are placed in large drying pans and placed in the dryer for about four hours at 105°C in order to be completely dry. Cooled samples are first crushed to approximately 75% passing -8 mesh. One in every 21 samples is screened for percentage passing – 8 mesh. After this first step of comminution, this material is called a “coarse” sample.

The samples are then riffle split to approximately 800 g and the rest of the coarse sample is kept by the laboratory until the geology department decides which coarse rejects can be discarded. The coarse samples are then pulverized to approximately 95% passing – 170 mesh. This material is now called “pulp”. One in every 21 samples is screened for percentage passing – 170 mesh. Thirty grams of pulp are sampled and the rest of the pulp sample is kept by the lab until the geology department decides which pulp rejects can be discarded.

11.1.1.2

RGM SAMPLE PREPARATION FOR PULVERIZING AND LEACHING

The whole samples (5 kg) are placed in large drying pans and placed in the dryer for about four hours at 105°C in order to be completely dry. Cooled samples are first crushed to approximately 75% passing -8 mesh. One in every 52 samples is screened for percentage passing – 8 mesh. After this first step of comminution, this material is called a “coarse” sample.

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Technical Report NI 43- 101 – November 5, 2018 Page 11-1



The samples are then riffle split to approximately 800 g and the rest of the coarse sample is kept by the lab until the geology department decides which rejects can be discarded. Three hundred grams of coarse material are sampled for assaying.

11.1.1.3

FILAB SAMPLE PREPARATION FOR FIRE ASSAY

The SurEx 2017 campaign was analysed at Filab, an external laboratory. The procedure is similar to that used at the RGM Laboratory. The only change is the proportion of samples kept after splitting around 300g of coarse material and the 50g sent for assaying.

11.1.2

ANALYSIS


11.1.2.1

LABORATORY

After the samples have been split and put in pre-identified plastic bags, they are delivered by the core shack personnel to the RGM Laboratory or transported by a contractor to an external Laboratory in Paramaribo (since 2009). Since 2014, Filab and ENZA are used as check laboratories by RGM Laboratory for the Fire Assay process. For the PAL samples, RGM Laboratory is using, as external laboratories, CRS-Actlab, Merian Gold Mine Laboratory (Suriname, Newmont), and ENZA Analytical Services.

The RGM Laboratory, associated with the Mill, is fenced and has security posted at the entrance. As soon as they arrive at the laboratory site, samples are registered either into the Laboratory Information Management System (LIMS, RGM), are scanned and given an internal ID (Filab), and are then stored. To ensure the integrity of each sample shipment, the core shack supervisor/geologist from the Mine Exploration department, using the submittal sheet, verifies that all samples are accounted for when the samples are shipped out. A submittal sheet is forwarded, as well, to the laboratories to verify, at the receiving end, that no sample is missing.

11.1.2.2

RGM FIRE ASSAY

Approximately 30 g of the pulp 95% passing approximately 170 mesh is used for the fire assay manipulation. This pulp material is mixed with the appropriate flux and silver nitrate solution and is placed in a crucible. Fusion of the sample occurs in a furnace for 45 minutes at 900°C. When cooled, the lead-button containing gold is separated and put in a pre-fired cupel which is positioned in the furnace for 30 minutes at around 950°C. When no more molten lead is visible, the gold-silver bead stays in the cupel. The sample is ready for the atomic absorption finishing.

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11.1.2.3

RGM PULVERIZE AND LEACH SYSTEM

Around 300 g of the coarse material > 75% passing 8 mesh is precisely measured and used for the PAL manipulation. This pulp material is put in an iron container with 1,000 ml of water, two cyanide assay tabs, and with a few steel balls (two balls of 36 mm, four balls of 27 mm, and 1 kg of 12 mm). The PAL machine grinds and leaches the material for 90 minutes. An aliquot of 10 ml is collected per pot (The PAL runs 52 pots at the same time). The aliquot is sent for atomic absorption analysis after having filtered the grind media out.

11.1.2.4

FILAB FIRE ASSAY

The analysis procedure of Filab remain the same as the RGM Laboratory with the exception that 50 g of the pulp is used for the fire assay manipulation.

11.1.2.5

ATOMIC ABSORPTION AND GRAVIMETRY

The majority of the analyses are made by atomic absorption. This technique makes use of absorption spectrometry to assess the concentration of an analyte in a sample.

For Fire Assay, the gold is not analyzed directly, but rather in solution. The sample is placed in test tubes and digested into HNO3 HCL (aqua regia) before readings on the atomic absorption spectrometer.

For PAL, the solution collected out of the PAL process is read by the atomic absorption spectrometer by direct aspiration.

In case of a high concentration of gold, the sample may be subject to gravimetric finishing by directly weighing the gold. A computer is connected to the machine and records all the collected assays.

11.1.3

QUALITY ASSURANCE AND QUALITY CONTROL


11.1.3.1

BLANKS

The blanks are chronologically plotted. The safety limit is defined by two times the detection limit for pulp blank and by three times the detection limit for coarse blank. The RGM Laboratory detection limit adds up to 0.014 g/t Au.

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If any blank is higher than any of these defined safety limits, a contamination issue is detected and the batch or the sequence of samples related to this contaminated blank has to be re-assayed.

A contamination period is considered when 10% of the coarse blanks or 5% of the pulp blanks exceed the safety limit. In that case, all the assays between problematic blanks have to be assayed again and a long term investigation has to be run.

11.1.3.2

STANDARD REFERENCE MATERIAL

Different charts are used to analyze the standard reference material (SRM) assays:

A classical control chart, plotting the results in chronological order as well as the SRM reference value, the experimental mean and the experimental standard deviation (σ). This first chart is usually useful to detect quickly outliers (all values outside the interval defined by the experimental mean +/- 3*σ).

   

A bias chart with moving average of the assays plotting within confidence intervals. This visual approach highlights the portions of the moving average exceeding the limits of the confidence interval and shows up the batches that need to be re-analyzed.

If any standard fails, all the samples between this standard reference material and the next one and the previous one have to be re-assayed. If a trend or bias is observed, an investigation has to be run to solve the origin of this abnormal behavior.

11.1.3.3

DUPLICATES AND CHECK ASSAYS

Two different graphs are used to plot this kind of control:

The first one is a scatter plot of the duplicate/check assays versus the original sample assays to visually detect outliers. All the pairs of data outside the two rejected curves are considered as outliers.

   

The second one is a relative difference control chart. The relative difference is computed with the original sample assays and the duplicate/check assays. It is plotted in function of the original sample grades. A moving average is also calculated to help the reading of the chart.


11.1.3.4

MINE GEOLOGY DEPARTMENT QUALITY CONTROL PROCEDURES

Since the needs of the Mine Exploration department and Mine Geology department differ to some extent, the bulk of the procedure is the same as for the Mine Exploration department. The quality control process will show slight differences, however, the overall goal remains the same, to ensure that both departments can rely on the assay results.

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Technical Report NI 43- 101 – November 5, 2018 Page 11-4



The RGM Laboratory quality control is made internally and by the client (Mine Geology department) in order to maintain the highest possible standard controls. Quality control is provided by the Mine Geology department for the RC samples and the blast hole samples by requiring regular re-tagged coarse reject duplicates and by submitting Field Duplicates. Since the blast holes assays are not used in the resource and reserve estimations, the quality assurance/quality control (QA/QC) results will be developed only for the RC assays (Table 11-1):

Coarse Reject Duplicates: 1% of the unused fraction of the crushed rock sample has been retagged. They are used to evaluate the reproducibility of results.

   

RC Field Duplicates: 3-5% of the remaining half-split of a RC-sample is afterwards mixed / split / and retagged with a different number. They are used to verify the homogeneity of a sample after splitting out in the field.

   

Standard Reference Materiel: 0.2% of the sample send to RGM lab are SRM used to check the QA/QC of the RGM Lab.

No major bias has been observed in 2017.

TABLE 11-1     PULVERIZE AND LEACH STANDARD REFERENCE MATERIAL
 SUMMARY 2017

Mine Geology Department Quality Control
Type of samples RC
Assaying Method PAL
Number of Sample 200,498
Number of SRM 325
% of SRM 0.2%
Number of SRM Outlier 26
% of SRM Outlier 8.0%
Number of Coarse Reject Duplicate 824
% of Coarse Reject Duplicate 0.41%
Number of Coarse Reject Duplicate Outliers 34
% of Coarse Reject Duplicate Outliers 4.13%
Number of Field Duplicate 6,982
% of Field Duplicate 3.48%
Number of Field Duplicate Outliers 294
% of Field Duplicate Outliers 4.21%

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11.2

SARAMACCA CONCESSION


11.2.1

SAMPLE PREPARATION AND ANALYSES

No information exists regarding laboratories used by Golden Star and Newmont for exploration samples collected between 2005 and 2010.

Exploration samples collected by IAMGOLD-RGM SurEx from 2016 to 2018 were submitted to Filab in Paramaribo, Suriname, the representative of ALS Global in Suriname, N.V. Samples collected by IAMGOLD-RGM MinEx in 2018 were submitted to RGM laboratory (RGM lab). Umpire testing of samples from both MinEx and SurEx groups was conducted through ALS Minerals laboratory (ALS) in Vancouver, Canada. Filab and ALS are autonomous, commercial geochemical laboratories that operate independently of IAMGOLD-RGM. The RGM laboratory is an internal mine laboratory operated by IAMGOLD-RGM.

Filab and ALS have been accredited to ISO/IEC 17025 for geochemical analyses, including those used by IAMGOLD-RGM. Filab and RGM lab are audited, at least bi-monthly, by IAMGOLD-RGM staff. ALS is accredited to ISO/IEC 17025 by the Canadian Association for Laboratory Accreditation, Inc. (CARLA) with registration number A1719, including those used by IAMGOLD-RGM. RGM lab has been accredited to ISO 17025 (accreditation number A3711) and has been audited by IAMGOLD-RGM staff a total of 19 times between January and April 2018.

11.2.2

GOLDEN STAR AND NEWMONT (PRE-2016)

Sample preparation, analysis and security procedures for samples taken by Golden Star and Newmont from 2005 to 2010 are undocumented and therefore unavailable for review.

11.2.3

IAMGOLD-RGM (2016 – 2018)

Sampling procedures are described in Section 10. All samples were collected by, or under the secure supervision of, IAMGOLD-RGM personnel, from the time of sampling through to being received at the primary laboratory.

Samples are transported exclusively by IAMGOLD-RGM personnel or by an independent contractor, Vonkel, between the drill site, Saramacca camp, RGM lab, and Filab. The samples are recorded on the chain of custody (COC) form, grouped by borehole and signed off by both the sender and receiver of samples at each transportation stage between the drill site and laboratory. The signed chain of custody forms are scanned, filed, and stored, both digitally and as a hard-copy. Reference halved-core, pulps, and rejects are stored within a secured perimeter at the RGM mine site.

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11.2.4

SUREX (OCTOBER 2016 – DECEMBER 2017)

Samples collected from DD and RC drilling by IAMGOLD-RGM SurEx are transported in sealed bags to Filab where they were weighed, dried, coarse-crushed to <2.5 mm and between 350 to 450 g were pulverized to 85% passing <100 microns. Gold was analyzed in both DD and RC samples at Filab using 50 g charges by fire assay with atomic absorption finish to a detection limit of 0.005 g/t (Filab code FA50). After 2017, samples exceeding 5 ppm were reanalyzed with a gravimetric finish. The pulps from the 2016 DD drilling campaign were also assayed for a suite of 40 elements using four acid digestion and inductively-coupled plasma emission spectroscopy (ICP-ES) (Filab code ICP40). Representative samples of each rock type are taken from each drill hole for bulk density measurements.

The excess material coarse rejects and pulps of DD and RC samples sent to Filab were returned to IAMGOLD-RGM and stored securely on site. A portion of these samples (approximately 8% of total samples) were selected for check assay testing either randomly or to corroborate specific assay results at the umpire laboratory. Check assay analysis was completed at ALS by fire assay using 50 g charges with an atomic absorption finish to a detection limit of 0.005 g/t Au (method code FA-AA25).

11.2.5

MINEX (JAN 2018 – APRIL 2018)

Core samples collected through DDH drilling by IAMGOLD-RGM MinEx were submitted to the RGM Laboratory. Samples are dried in large drying pans in the dryer for four hours at 105° C. Once cooled, samples are crushed with a Bico-Badger crusher to approximately 75% passing a -8 mesh, however, a primary crusher is required if the samples are coarse (>50 mm). The samples are then rifle split to approximately 800 g. The remainder of the sample is stored in plastic bags as coarse reject.

Coarse samples are pulverized to approximately 95% passing -170 mesh with a Bico UA pulverizer. Thirty grams is homogenized by rolling and used for analysis. The remaining material is stored in a plastic bag as the pulp reject. Gold is analyzed by fire assay on 30 g charges with an atomic absorption spectroscopy finish to a detection limit of 0.014 g/t Au (RGM method code FA-AAS).

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Technical Report NI 43- 101 – November 5, 2018 Page 11-7



A sand wash is used between pulverizing samples to clean the tool surfaces and prevent contamination.

The RGM laboratory is fenced and the entrance is guarded by security. Samples are registered into the LIMS upon arrival at the laboratory to manage assay data and automatically collect assay information and store it securely on the server.

Umpire check assays were performed at ALS in Vancouver on pulp and coarse reject material by fire assay using 50 g charges with an atomic absorption finish to detection limits of 0.005 g/t Au on 50 g charges (ALS method code FA-AA25). Samples grading over 5 g/t Au are analyzed by gravimetric finish.

11.2.6

QUALITY ASSURANCE AND QUALITY CONTROL PROGRAMS

Quality assurance and quality control programs are typically set in place to ensure the reliability and trustworthiness of the exploration data. They include written field procedures and independent verifications of aspects such as drilling, surveying, sampling and assaying, data management, and database integrity. Appropriate documentation of quality control measures and regular analysis of quality control data are important as a safeguard for the project data and form the basis for the quality assurance program implemented during exploration.

Analytical control measures typically involve internal and external laboratory control measures implemented to monitor the precision and accuracy of the sampling, preparation, and assaying. They are also important to prevent sample mix-up and monitor the voluntary or inadvertent contamination of samples. Assaying protocols typically involve regular duplicate and replicate assays and insertion of quality control samples. Check assaying is typically performed as an additional reliability test of assaying results. This typically involves re-assaying a set number of rejects and pulps at an umpire laboratory.

11.2.6.1

GOLDEN STAR AND NEWMONT (PRE-2016)

There are no records of quality assurance and quality control protocols or performance for exploration work performed by Golden Star and Newmont from 2005 to 2010.

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11.2.6.2

IAMGOLD-RGM (2016- 2018)

IAMGOLD-RGM follows a quality assurance/quality control protocol which involves:

  The insertion of CRM
     
  The insertion of certified pulp and rock blanks
     
  The insertion of uncertified commercial rock blanks, which were tested to be barren
     
  Field duplicates in RC holes
     
  Check assays (coarse rejects and pulps)
     
  Periodic audits at the primary laboratories, Filab, and RGM laboratory

IAMGOLD-RGM’s procedures for quality control sample insertion rates are outlined in Table 11-2.

TABLE 11-2     STANDARD PROCEDURE FOR QUALITY CONTROL SAMPLE
INSERTION RATES, SARAMACCA PROJECT

Blanks CRMs Field Duplicates Check Assays
(Pulps) (%)
Check Assays
(Rejects) (%)
SurEx          
DD drilling 1 every 20 1 every 20 None 5% to ALS 5% to ALS
RC drilling 1 every 20 1 every 20 None 5% to ALS 5% to ALS
Failure limit 0.1 g/t +/- 3 SD* +/- 20 percent - -
Corrective action Reject or resend
(+/- 10 samples)
Reject or resend
(+/- 10 samples)
- - -
MinEx          
DD drilling 1 every 30 1 every 30 None 5% to ALS
2% to RGM
5% to ALS
2% to RGM
Failure limit 0.048 g/t +/- 3 SD* - - -
Corrective action ¼ core resampled
between two
acceptable blanks
Pulps resent between
two acceptable
standards
- - -

* Standard deviation

Commercial CRM were sourced from Ore Research & Exploration Pty Ltd Of Australia (OREAS) and Rocklabs Ltd. Of Auckland, New Zealand (Rocklabs). IAMGOLD-RGM has used a total of 11 CRM types between July 2017 and April 2018 ranging from 0.20 g/t Au to 14.18 g/t Au and include both the oxide and sulfide facies, summarized in Table 11-3.

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Blank materials 24c and 26b utilized by SurEx were sourced from OREAS with a certified value of 0.01 g/t Au. Field blank material was sourced locally from a sill known to be barren with respect to gold and is considered a coarse blank.

In the case of a failure of control samples, quartered DD or RC pulps between two acceptable CRM or blanks surrounding the significant failure are resubmitted to the primary and secondary lab respectively. New control samples are inserted at the same frequency as for primary samples.

In addition to the inserted control samples, IAMGOLD-RGM SurEx collected one field duplicate every 25 samples from RC holes. No field duplicates were systematically collected in drill core.

Check assaying of coarse reject and pulp material was performed on approximately 2 percent of MinEx samples at the primary laboratory, chosen randomly or to corroborate specific assay results. Approximately 3 percent of SurEx coarse duplicate samples were submitted for similar check assaying to the primary laboratory.

As part of the analytical data verification, SurEx and MinEx submitted sample pulps to ALS in Vancouver for umpire check assay testing between July 2017 and April 2018. The samples cover a range of gold values and were assayed by fire assay with an atomic absorption finish (ALS method code FA-AA25 or FA-AA26).

TABLE 11-3     SUMMARY OF CERTIFIED REFERENCE MATERIALS USED BY
IAMGOLD-RGM FROM JULY 2017 TO APRIL 2018

Low grade Gold (0-1 ppm)   Medium Grade Gold (1-5 ppm)   High Grade Gold (>5 ppm)
Standard
ID
Expected
Value
SD* Inserts   Standard
ID
Expected
Value
SD* Inserts   Standard
ID
Expected
Value
SD* Inserts
SurEx                          
250 0.309 0.013 288   209 1.58 0.044 296   210 5.49 0.152 126
252 0.674 0.022 228   254 2.55 0.076 30   257 14.18 0.264 7
202 0.752 0.026 385                    
MinEx                          
OXC88 0.203 0.01 157   SG56 1.027 0.033 95          
SE58 0.607 0.019 18   SJ53 2.637 0.048 67          
Total     288   Total     326   Total     133

* Standard Deviation

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11.2.7

SRK COMMENTS

SRK reviewed the field procedures and analytical quality control measures used at the IAMGOLD-RGM Saramacca gold project. In the opinion of SRK, company personnel used care in the collection and management of the field and assaying exploration and production data.

With the handover of the project to MinEx in early 2018 the samples are now being analyzed at the internal RGM laboratory. Based on SRK’s review, the RGM internal laboratory used procedures and equipment that are adequate for the analysis of gold from the Saramacca project.

In the opinion of SRK, the sampling preparation, security, and analytical procedures used by IAMGOLD-RGM are consistent with generally accepted industry best practices and are, therefore, adequate for informing Mineral Resources.

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12

DATA VERIFICATION


12.1

RGM CONCESSION DATA VERIFICATION


12.1.1

DATABASE ORGANIZATION

The whole mineral inventory is monitored through GEMS 6.7 by Dassault Systèmes which is supported by centralized SQL Server 2014 databases. These SQL databases are hosted on a virtual SQL server under the responsibility of the IT department while the databases themselves are under the responsibility of the database administrator.

GEMS is mainly used by: 1) the geologists for reserve and resource estimations, geological modelling, management of the drilling campaign, and packet design; 2) the mine planners to complete pit designs, short term planning, and whittle shells and; 3) the surveyors to record spatial information.

Each pit in the RGM concession forms a distinct GEMS project and so, constitutes an individual database. The GEMS projects are made of different workspaces which are a grouping of data within a project on the basis of type, such as points, drill holes, polylines, polygons, and triangulations (solids and surfaces). Workspaces are organized into tables, with each workspace consisting of at least one header table and potentially an unlimited number of sub-tables.

The database has a high security level administered in SQL via SQL Server Management Studio, a graphical interface of SQL 2014. The mine employees requiring the use of GEMS are first added to the SQL server users list through SQL Server Management Studio with their Domain Login names. Then, for each database, the user is added to a role, which is a SQL group of users with specific permissions.

In SQL, for each project there are six main roles having distinct permissions for each workspace (BLOCK, SUR, PLN, GEO, ENG, and OC). When a user is added to a role, he/she automatically gets the permissions attributed to this role. Special restrictions are applied for critical data: 1) the block model workspaces can only be modified by the resource geologists and the database administrator; 2) the assays table from drill holes are read-only once the results have been imported. The management of those permissions is monitored by a limited number of qualified persons.

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Backups of the databases are made daily under the supervision of the database administrator. These backups are part of a back-up plan that automatically runs every night. The last six backups are kept on the server and one backup, a week, is transferred to another server and is kept for five weeks. The IT department also carries out a complete backup of the server VROSGEMS01 every day and monthly. Daily backups are incremental and the monthly backups are stored on tape.

12.1.2

DRILL HOLE VALIDATION

The geological data from the exploration program is imported in the database via LogChief, a logging software provided by Maxwell Geoservices, which is linked to the central database.

After the logging and assaying information have been imported into GEMS through the logger, the geologist who logged the hole and his supervisor are responsible to do a validation of his data including: 1) visual validation of the drill hole in Gems; 2) cross check for overlapping and missing intervals using the Gemcom validation tool; 3) do the quality control (QC) check on the samples when the results are received.

When the QC has been completed and all of the data has been validated, confidence in this data is considered adequate to be used in the Mineral Resource estimations. Beyond this, an extra validation is completed by the resource geologist to ensure the integrity of the data used.

It is the QP’s opinion that the logging, sampling procedures, and data entries were completed to industry standards. It is the QP’s opinion that the database is adequate to support a Mineral Resource estimate on the RGM property.

12.2

SARAMACCA CONCESSION DATA VERIFICATION


12.2.1

VERIFICATIONS BY IAMGOLD-RGM

IAMGOLD-RGM employed quality control procedures and quality assurance actions to provide adequate confidence in data collection and processing. During drilling, experienced IAMGOLD-RGM geologists implemented industry standard measures designed to ensure the reliability and trustworthiness of exploration data.

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Database verifications consisted of monitoring all data imported into the database for errors, such as overlapping sample intervals or missing information. Monitoring of data was completed manually, and with the use of a database program.

Regular analysis of analytical quality control data was undertaken by IAMGOLD-RGM following the IAMGOLD Fire Assay Guidelines. These guidelines state that when a quality control failure occurs, all samples between two acceptable standards surrounding the failure must have their rejects and pulps re-assayed with new control samples, and the project geologist is notified of the failure. A quality control failure was defined by IAMGOLD-RGM as, for any given sample batch, the analysis of two standard samples outside of two standard deviations, or one standard sample outside of three standard deviations.

12.2.1.1

SUREX

As part of the analytical data verification, IAMGOLD-RGM SurEx submitted 1,188 sample pulps to ALS in Vancouver for umpire testing between July 2017 and April 2018. The samples cover a range of gold values and were assayed by fire assay with an atomic absorption finish (ALS method code FA-AA25). Additionally, routine monthly audits of Filab were performed by IAMGOLD-RGM SurEx staff.

IAMGOLD-RGM SurEx staff reviewed and documented the performance of CRM and duplicate testing in monthly internal reports. SurEx staff identified quality control material failures and investigated the cause of each, supported by laboratory audits. In March of 2018, a field duplicate bias was identified and after investigation it was reported to be due to improper alignment of the cyclone splitter during sampling and was corrected.

12.2.1.2

MINEX

Monthly internal QA/QC reports document in detail the monitoring of quality control samples performance from January to April 2018. Where MinEx personnel have identified CRM failures, sample batches have been resubmitted for repeat analysis and the new certificates were used in replacement of the originals. In March 2018, a positive bias of duplicate assay results was detected by MinEx staff. Although an investigation with the primary laboratory did not reveal any issues, 30 additional samples were sent to the umpire laboratory for repeat analysis to ensure the reliability of the assay results.

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Umpire testing by IAMGOLD-RGM MinEx in 2018 involved submitting 374 sample pulps to ALS in Vancouver for analysis by fire assay with an atomic absorption finish (ALS method code FA-AA26). Additionally, routine weekly audits of RGM lab were performed by IAMGOLD-RGM MinEx personnel.

12.2.2

VERIFICATIONS BY SRK


12.2.2.1

SITE VISIT

In accordance with NI 43-101 guidelines, Dominic Chartier, P.Geo. (OGQ #874, APGO #2775), visited the Saramacca gold project from January 22 to 26, 2018, accompanied by Caroline Laplante and Samuelle Gariepy, geologists with IAMGOLD-RGM’s Suriname Exploration department.

The purpose of the site visit was to review the updated exploration database and validation procedures, review exploration procedures, examine drill core, interview project personnel, reassess geological modelling procedures, update the geological model, and collect all relevant information for the preparation of a revised Mineral Resource model and the compilation of a technical report.

SRK was given full access to relevant data and conducted interviews with IAMGOLD-RGM personnel to obtain information on the past exploration work, to understand procedures used to collect, record, store and analyze historical and current exploration data.

12.2.2.2

VERIFICATIONS OF ANALYTICAL QUALITY CONTROL DATA

Drilling data on the Saramacca gold project between 2016 and July 2017 was verified within the 2017 Technical Report (SRK, 2017b). SRK deemed the analytical results delivered by Filab laboratory as sufficiently reliable for the purpose of Mineral Resource estimation.

SRK analyzed the analytical quality control data produced by IAMGOLD-RGM from the drilling programs conducted by SurEx and MinEx on the Saramacca gold project since the September 5, 2017 Mineral Resource estimate. All data were provided to SRK in Microsoft Excel spreadsheets. SRK aggregated the assay results of the external analytical control samples for further analysis. Control samples (blanks and CRM) were summarized on time series plots to highlight their performance. Paired data (preparation, pulp, umpire, and laboratory internal pulp duplicate assays) were analyzed using bias charts, quantile-quantile, and relative precision plots. A selection of the charted data is presented in Appendix A. The type of analytical quality control data collected, and their associated performances are discussed below and summarized in Table 12-1.

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TABLE 12-1     SUMMARY OF ANALYTICAL QUALITY CONTROL DATA
PRODUCED BY IAMGOLD-RGM ON THE SARAMACCA GOLD PROJECT (JULY
2017 – APRIL 2018)

                                  Gold
    SurEx   (%)   MinEx     (%)   Total   (%)   Comment   (g/t)
Sample Count   14,404       10,582         24,986            
Blanks   1,449   10.06   459     4.34   1,908   7.64        
Blanks – Field   378       459         837       Barren Sill    
Blanks – 26b   476                 476       OREAS    
Blanks – 24c   595                 595       OREAS    
QC samples   1,360   9.44   337     3.18   1,697   6.79        
OXC88           157                 Rocklabs   0.203
250   288       -                 OREAS   0.309
SE58           18                 Rocklabs   0.607
252   228       -                 OREAS   0.674
202   385       -                 OREAS   0.752
SG56   -       95                 Rocklabs   1.027
204   -       -                 OREAS   1.043
209   296       -                 OREAS   1.58
16a   -       -                 OREAS   1.81
254   30       -                 OREAS   2.55
SJ53   -       67                 Rocklabs   2.637
17c   -       -                 OREAS   3.04
210   126       -                 OREAS   5.49
257   7       -                 OREAS   14.18
Coarse Duplicates   433   3.01   186     1.76   619   2.48   Blind Checks    
Pulp Duplicates   -   -   205     1.94   205   0.82   Blind Checks    
Total QC Samples   3,242   22.51   1,187     11.22   4,429   17.73        
Check Assays                     2,121   8.49        
Filab and ALS   4,693*   *                     *2016 to 2017    
RGM-ALS           467     4.41   467   1.87%   Coarse Rejects    
RGM-ALS           466     4.40   466   1.87%   Pulps    

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12.2.2.3

SUREX

The performance of control samples analyzed by Filab is considered acceptable. Over 98% of the certified and uncertified blanks returned values below ten times the detection limit, indicating no apparent contamination during the sample preparation stage.

CRM performed reasonably with most of failures due to the probable mislabelling of standards. Most certified standards assayed within two standard deviations of the expected limit. Samples outside the range of two standard deviations appear to be largely due to the mislabelling of standards. Some bias, however, is observed with reference materials OREAS 250, OREAS 252, OREAS 254, and OREAS 210 and further investigation is recommended. The results indicate poor analytical accuracy for of these standards potentially due to poor calibration. Analytical bias is not detected for other reference materials used during the same time period.

Paired data of coarse reject duplicate samples submitted during the 2017 to 2018 RC and DD drilling programs indicate that Filab had moderate difficulty in reproducing the results. Ranked half absolute relative difference (HARD) plots suggest that 38.8% of the coarse reject duplicates have HARD below 10%. Poor reproducibility of coarse duplicates, however, is not unexpected for sampling mineralization characterized by this type of deposit. Results for samples grading less than 0.3 g/t Au appear to have a minor negative bias when coarse reject material is re-assayed. This affect is minimal, and no bias is detected with samples of higher grade.

Approximately five percent of samples analyzed by Filab were chosen either randomly or as representations of significant intercepts from additional pulp material and sent to ALS for repeat analysis between 2016 and 2018. Ranked HARD plots suggested that 32% of the umpire check assays conducted on pulps, had HARD values below 10%, suggesting poor reproducibility between the two laboratories. This may be due to insufficient pulp sample homogenization at the primary laboratory.

12.2.2.4

MINEX

The performance of control samples analyzed by RGM Lab Suriname is considered acceptable. All blank material samples returned values below ten times the detection limit, indicating that contamination during the sample preparation has not been identified or very minimal.

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CRM performed reasonably for an internal mine laboratory with the majority of failures monitored closely and investigated by IAMGOLD-RGM staff. Most certified standards assayed within two standard deviations of the expected limit, however failure rates for standards SG56 and SJ53 are over 30%. The results may indicate poor analytical precision or reference material homogenization in the case of these standards and the issue cannot be rectified at the lab, replacement should be considered.

Paired data of coarse reject duplicate samples submitted during the 2018 DD drilling program indicate that RGM lab had little difficulty in reproducing the results. Ranked HARD plots suggest that 63.3% of the coarse reject duplicates have HARD values below 10% with no obvious bias detected. Paired data of sample pulp duplicates indicate that RGM lab had moderate difficulty in reproducing the results. Ranked HARD plots suggest that 51.1% of the pulp duplicates have HARD values below 10% with no obvious bias detected. Poorer reproducibility of pulp duplicates compared to coarse rejects is unexpected as the pulp should be more homogeneous. The reason for the difference is unknown.

Approximately nine percent of samples analyzed by RGM Lab were chosen either randomly or as representations of significant intercepts from additional coarse reject or pulp material and sent to ALS in Vancouver for umpire check analysis. Ranked HARD plots suggested that 46% of the umpire check assays conducted on coarse rejects, and 57.7% for pulps, had HARD values below 10%, suggesting moderately poor reproducibility between the two laboratories but within expected ranges for this type of deposit.

12.2.3

SRK COMMENTS

SRK carried out a detailed quality control review including the review of analytical quality control programs carried out by IAMGOLD-RGM from July 2017 to April 2018. The aim of this review was to verify the reliability of exploration data generated during this period to be used in the Mineral Resource update and feasibility study. This review is in addition to that conducted and discussed in the 2017 report which deemed the analytical results delivered by Filab as sufficiently reliable for the purpose of Mineral Resource estimation.

In its review of quality control data, SRK identified a high failure rate for certain control samples used by MinEx and submitted to RGM Laboratory. IAMGOLD is proactive in discussing and investigating failures with all laboratories, and continued diligence in monitoring quality control data and implementing appropriate corrective action is strongly encouraged.

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In the opinion of SRK, the paired data results are mostly consistent with results expected for this type of gold mineralization. Pulp replicate results are poorer than expected for both SurEx and MinEx sampling and suggest insufficient homogenization during the sample preparation stage at the primary laboratories. The umpire check assays show that the results produced by Filab can be reproduced within acceptable limits by ALS. Umpire laboratory testing for RGM laboratory reveals the moderately poor reproducibility but within expected ranges and no bias.

Overall, IAMGOLD-RGM has a well monitored and robust quality assurance and quality control program in place for the Saramacca gold project. Laboratory audits and monthly quality control data analysis by both SurEx and MinEx departments are well documented. SRK considers analytical results from RC and DD sampling conducted at Saramacca are globally sufficiently reliable for the purpose of resource estimation. The data examined by SRK do not present obvious evidence of analytical bias.

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13 MINERAL PROCESSING AND METALLURGICAL TESTING

Metallurgical testing on the RGM deposits has been carried out since 1995 in order to understand the metallurgical characteristics of the deposits. The Rosebel Gold Mine has been in operation since 2004, hence this section summarizes the work, completed to date, to define the metallurgical characteristics of current and remaining ores in the RGM deposits.

13.1

RGM METALLURGICAL TESTING


13.1.1

INTRODUCTION

Since 1995, several metallurgical test work campaigns were carried out on composite samples from each of the pits at Rosebel Gold Mine. The test work included programs at Hazen Laboratory (1995), Mineral Resources Limited (1996), and Kappes Cassiday Associates (1999). The outcome of this test work dictated the design of the original plant.

According to the life of mine (LOM) plan and historical data, the processing plant faced new challenges in limitations to processing ore with a greater hard rock ratio (10% and up). Based on this limitation, IAMGOLD made a decision to perform numerous plant surveys and ore type characterization to better understand the bottlenecks and to predict the future mill performance. In addition to that main objective, the application of results obtained through RGM’s Plant Optimization Program (POP) has shown benefits to Rosebel mill performance, specifically recovery and throughput.

This section summarizes the major conclusions and outcomes from the metallurgical testing completed since operations began in 2004. Table 13-1 summarizes the optimization phases:

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TABLE 13-1     OPTIMIZATION METALLURGICAL TEST WORK PERFORMED

From Report Title Date Information
    An Investigation into    
  the Grindability    
 SGS1 11700-001 - Final Report Characteristics of 27-Feb- 08 Grindability tests (BWI, AL, CWI, RWI)
    Samples    
    A Plant Audit    
    Investigation into the   This report covers the grinding audit
SGS 12322-001 - Final Report #2 Rosebel 06-Dec-10 activities (Audit 1 & 2) and is an update of
    Concentrator   the report issued on 23-Dec-09
        Test work was conducted on carbon and
        pulp samples from the CIL plant at Rosebel
    An Investigation into   to determine the activity of plant regenerated
    the Efficiency of the   carbon relative to fresh carbon samples, and
SGS 12322-001 - Report 3 Rosebel CIL Plant 09-Dec-10 to conduct bench-scale characterization test
    Operation   work (including comminution, mineralogy,
      and chemical analysis) and metallurgical
        variability testing (including gravity
        separation and cyanidation).
    The Characterization    
SGS 12322-002 - Final of Rosebel Ore 08-Dec-10  
    Types    
    An Investigation into    
    the Capacity of the   The results of the surveys performed under
SGS 12322-004 - Final Report Rosebel Grinding 23-Feb- 11 SGS project 123322-001 were used to
    Circuit Throughout   develop a comminution production forecast
    the Life of Mine   model
    An Investigation into    
    the Grindability   Bond low energy impact testing of three rock
SGS 13249-002 Characteristics of 28- Jun-12  
    Three Samples from   samples from Rosebel deposit
    Rosebel Mine    
      Geology study for sample selection,
    Forecasting and   grindability test work, geostatistical analysis
    Optimization of the   of the data and distribution to the mine
SGS 13249-001 - Final Report Rosebel 31-Mar-14 blocks, reconciliation of the CEET™ model
    Concentrator Using   using historical data and throughput
    CEET™   forecasting based on the mine plan.
        Determine the amount of gold and the
    IAMGOLD Rosebel   deportment of gold within the gravity circuit,
Sepro2   Mine Gravity Circuit 10-Dec-10 as well as the proportion of gravity
    Audit   recoverable free gold at various places
        within the circuit
  Gravity Circuit    
Knelson3 101220- 0600-143   10-Dec-10 Gravity circuit modelling
    Considerations    
    PICA Carbon Testing   Audit on activated carbon quality, acid
PICA4   & Circuit Auditing 14-Dec-10 washing, elution, regeneration, and gold
    Circuit   adsorption properties
    The Grinding Circuit    
    Benchmarking and    
    CEET2 Model   Survey of the grinding circuit, update the
SGS 13249-003 - Final Report Development for the 10-Jul-18 CEET2 model and revise the LOM
    Rosebel   throughput forecasting simulations
    Concentrator  

Notes:

  1

SGS Lakefield Research Limited (SGS Lakefield)

  2

Sepro Mineral Systems Corp. (Sepro)

  3

Knelson Gravity Solutions (Knelson – now FLSmidth Knelson)

  4

PICA SASU (now Jacobi Carbons)

Figure 13-1 summarizes the main expansion initiatives since 2004 in order to increase the throughput and accommodate the amount of hard rock treated while maintaining the same gold recoveries.

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Technical Report NI 43- 101 – November 5, 2018 Page 13-2



FIGURE 13-1     MAIN EXPANSION INITIATIVES SINCE 2004

13.1.2

METALLURGICAL CHARACTERIZATION

A metallurgical characterization program, developed in collaboration with SGS Lakefield and the site laboratory was implemented at Rosebel in late 2009 to optimize the current mill and support its evolution towards the processing of higher proportions of hard rock. Sepro and Knelson also performed a gravity investigation.

As the Rosebel processing plant receives fresh ore, on average, from seven different pits per year the forecasting of throughput is very challenging due to the wide range in ore grindability. A sampling strategy was developed and executed in 2009 with the geology team on site. The objective of the first step was to take samples from available drill cores to form composites that would characterize the different deposits in terms of major geological and mineralogical ore domains. The characterization program was carried out by SGS Lakefield focussing on hard rock material.

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The information from the metallurgical characterization program was also used for the calibration of a Comminution Economic Evaluation Tool (CEET™) Model. This tool was used in conjunction with the grindability values and the mine block model to forecast the grinding circuit capability and to identify potential bottlenecks. Through this characterization program the following steps were achieved:

  1.

Drill core samples composite characterizations;

     
  2.

Plant audit, including detailed surveys with a focus on the effect of the hard rock ratio;


  a.

First audit in December 2009, consisting of three grinding surveys;

     
  b.

Second audit in March 2010, consisting of three grinding surveys;

     
  c.

Third audit in February 2012, consisting of five grinding surveys with and without pre- crushed ore;

     
  d.

Fourth audit in February 2017, consisting of four grinding surveys


  3.

Modelling of the circuit based on the ore surveyed;

     
  4.

Grinding circuit evaluation using the CEET™ Model: maximum hard rock capacity of the current plant

The outcomes are used to estimate the maximum capacity of the existing circuit based on the yearly LOM update and to determine the equipment additions required to process more hard rock, going forward. To date, based on the conclusions from these studies, several additions have been made to the mill (Figure 13-1):

  A mobile pre-crushing circuit further replaced by a permanent pre-crushing circuit;
     
  A third ball mill;
     
  A gravity circuit;
     
  An intensive leach (Acacia reactor).

13.1.3

MINERAL COMPOSITION AND DISTRIBUTION

Table 13-2 and Figure 13-2 show the average mineral abundance, by rock type, measured by QEMSCAN. QEMSCAN is an abbreviation standing for Quantitative Evaluation of Minerals by SCANning electron microscopy.

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TABLE 13-2     AVERAGE MINERAL ABUNDANCE BY ROCK TYPE

  Average Mineral Mass (%)
Sample Saprolite Transition   Hard Rock
Cu-Sulphides 0.00 0.03 0.05
Pyrite 0.13 1.41 0.96
Pyrrhotite 0.00 0.01 0.42
Sphalerite 0.00 - -
Other Sulphides 0.00 0.01 -
Quartz 36.50 39.00 28.90
K- Feldspar 0.11 0.30 0.52
Plagioclase 1.72 10.40 22.90
Amphiboles 0.11 0.20 0.72
Biotite 0.42 0.50 0.18
Clays 34.30 20.00 9.82
Muscovite 13.40 14.50 8.28
Chlorites 3.52 8.15 13.10
Mag/Hematite 1.61 0.88 0.77
Goethite 5.54 2.41 0.54
Fe- Ti oxides 2.50 1.63 1.54
Calcite 0.01 0.01 0.95
Ankerite 0.03 0.26 9.58
Siderite 0.05 0.06 0.34
Gypsum 0.01 0.02 0.01
Apatite 0.02 0.12 0.35
Zircon 0.05 0.01 0.02
Other 0.00 0.01 0.05
Total 100 100 100

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FIGURE 13-2     AVERAGE MINERAL ABUNDANCE BY ROCK TYPE

Mineral abundance analysis has indicated that there is low exposure to deleterious elements which would represent a significant impact to the process. However, operationally, it has been observed that pyrrhotite, in higher concentrations, has negatively impacted leach dissolved oxygen levels with consequences to the leach kinetics. Additionally, ores with copper in higher concentration, have seen CIL carbon copper loading increase to concerning levels. In order to mitigate the above mentioned scenarios, actions have been to limit the problematic ore type reporting to the plant, which has allowed for normalized plant operation without an impact to the process performance.

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13.1.4

GRINDABILITY TESTING


13.1.4.1

DROP-WEIGHT TESTS

From 2004 to 2017 SMC testing (Drop-weight) was performed on the hard rock samples only. The SMC test is an abbreviated version of the standard JKTech drop-weight performed on 18 samples from a single size fraction (-22.4/+19.0 mm).

13.1.4.2

BOND BALL MILL GRINDABILITY TEST

From 2004 to 2017, a total of 63 drill core samples, comprised of four saprolite samples, 22 transition samples, and 37 hard rock samples, were submitted for Bond ball mill index (BWI) testing and the Bond abrasion testing (Ai).

The results are shown as overall grindability statistics in Table 13-3 below. The average grindability results by rock type in Table 13-4. The Axb and Bond Work Index per pit as a function of rock type is shown in Table 13-5.

TABLE 13-3     OVERALL GRINDABILITY STATISTICS

          JK JK JK    
  BWI BWI   Relative   Parameter  Parameter  Parameter  MacPherson  MacPherson
  (kWh/t)1 (kWh/t)2 AI (g) Density A x b3 A x b4 ta Test (kg/h) Test (kg/h)
Average 12.0 10.1 0.235 2.71 50.1 78.2 0.33 18.49 4.69
Standard Deviation 3.5 4.5 0.143 0.21 10.7 183.3 0.12 7.11 1.40
Minimum 2.7 0.8 - 1.77 37.7 22.4 0.21 13.35 3.15
10th percentile 7.2 2.7 0.058 2.64 41.3 25.4 0.23 13.78 3.53
25th percentile 10.5 6.4 0.133 2.73 46.7 26.9 0.25 14.44 4.09
Medium 12.6 11.7 0.229 2.76 55.6 31.4 0.28 15.53 5.03
75th percentile 14.1 13.3 0.305 2.80 56.2 38.8 0.35 21.06 5.46
90th percentile 15.0 14.6 0.414 2.82 56.6 66.7 0.55 24.39 5.72
Maximum 21.5 17.9 0.618 2.84 56.8 851.5 0.61 26.60 5.89

  AWI CWI CEET™ SPI Mod Bond
  (kWh/t) (kWh/t) Ci (min) (kWh/t)
Average 7.10 19.52 8.41 101.42 12.84
Standard Deviation 4.10 1.52 9.57 77.74 3.75
Minimum 2.72 18.37 0.59 0.27 1.26
10th percentile 3.72 18.51 1.41 5.98 8.64
25th percentile 5.22 18.72 1.98 23.68 10.77
Medium 7.71 18.98 3.64 101.72 13.90
75th percentile 9.28 19.78 12.44 167.45 15.56
90th percentile 10.23 20.96 21.90 210.38 16.22
Maximum 10.85 21.75 45.90 262.83 17.07

Notes:

  1

Measured Work Index


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  2

Recalculated Work Index with fines

  3

A x b from DWT

  4

A x b from SMC

TABLE 13-4     AVERAGE GRINDABILITY RESULTS PER ROCK TYPE

Rock Type Number
of
Samples
BWI
(kWh/t)1
BWI
(kWh/t)
AI (g)
Saprolite 4 19.1 5.0 0.148
Transition 22 8.7 4.2 0.071
Hard Rock 37 13.1 13.0 0.267

Notes:

  1

Measured Work Index

  2

Recalculated Work Index with fines

TABLE 13-5     AXB AND BOND WORK INDEX PER PIT IN FUNCTION OF THE
TYPE OF ORE

      BWI, kWh/t  
Pit A x b Hard Rock Saprolite Transition
Pay Caro 28.2 13.2 2.6 4.7
East Pay Caro 29.0 13.3 2.6 6.9
Koolhoven 36.8 12.7 2.6 5.1
J Zone 60.9 9.5 2.6 4.7
Royal Hill 28.5 13.4 2.3 4.7
Mayo 25.5 15.9 2.9 4.0
Roma 26.5 14.6 2.6 4.7
Rosebel 27.1 12.0 2.6 4.7

From the whole grindability test results the following conclusions were made:

  The average relative density ranged from 1.77 to 2.84;
     
Rock hardness, Axb, varied from 25.5 to 36.8 (very hard to hard) with one sample at 60.9. According to these grindability results;

  o The BWI of hard rock varied from 9.5 kWh/t to 15.9 kWh/t (medium to hard);
   
o The recalculated BWI of transition with fines ranged from 4.0 kWh/t to 6.9 kWh/t (very soft to soft);
   
o The recalculated BWI of saprolite with fines ranged from 2.3 kWh/t to 2.9 kWh/t (very soft);
   
o Abrasion Index, Ai, varies between 0.2 and 0.45 for hard rock with an average of 0.267. This was used to evaluate the steel consumption;

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13.1.5

GRINDING CIRCUIT SURVEYS

The first audit clearly showed the limitation of the existing mill to process more than 10% hard rock. Preliminary simulations were performed using JKSimMet, initially, and resulted in some challenges to forecast and predict the impact of pre-crushing on the grinding circuit. Therefore, a decision was made to use a CEET™ model. Once well calibrated, the CEET™ model is useful to forecast production. In order to calibrate the CEET™ model, one of the metallurgical parameters required is the semi autogenous grinding (SAG) Power Index (SPI) which is determined in the laboratory. The SPI is a measure of the hardness of the ore from the perspective of semi and fully autogenous milling (SAG/AG). It measures the time, in minutes, required to grind 2 kg of ore sample from 80% passing ½” (12.7 mm) to 80% passing 10 mesh (1.7 mm). Given that SPI values were not available from previous drill core characterization, a correlation was developed to convert available Axb values to SPI values in order to perform the first simulations.

Based on positive results from simulations, by using pre-crushing and benchmarking, it was decided in March 2012 to pre-crush the ore at the aggregate plant on site from run-of-mine down to -101 mm and send it to the mill for a trial. Based on the results, pre-crushing can increase hard rock grinding capacity by about 30%. This was confirmed by using a mobile crushing unit with different particle sizes (-101 mm, -75 mm, and -50 mm). The mobile crushing unit, with a capacity of 500 tonnes per hour (tph), was installed at the crushing plant from 2012 to 2016. The processing plant was able to maintain hard rock ratio as per predicted. In 2016, a permanent pre-crushing circuit was commissioned to replace the mobile circuit. With this new circuit the hard rock grinding capacity increased by about 15%.

Based on the surveys and simulations completed, a pebble crusher was installed in 2012 to maintain the increase in the hard rock ratio.

Optimization was also performed on the SAG mill in order to increase the throughput. Hard ore throughput rates are maximized via the use of aggressive lifter designs that project the largest amount of grinding media onto the toe of the mill charge.

For all subsequent grinding surveys the samples were characterized for SPI values in order to calibrate the CEET™ model. The model was subsequently updated with these SPI values. Figure 13-3 illustrates the latest update of the CEET™ model (Project 13249-003 – Final Report). The model is used to estimate the plant throughput of three scenarios with respect to hard rock competency, i.e. 1) hard; 2) medium; and 3) soft.

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FIGURE 13-3     CEET™ FORECAST

13.1.6

GRAVITY AND LEACHING TEST WORK

In 2010, the test work program performed at SGS Lakefield consisted of 24 samples, comprised of eight saprolite, four transition, and 12 hard rock which were submitted to metallurgical variability tests. A simplified gravity test was completed on the samples using a Knelson concentrator and a Mozley table to remove the coarse gold particles. This mimics the existing process flow sheet using gravity separation before the leach/CIL circuit.

Based on historical data, different surveys and laboratory test work performed in collaboration with Sepro and Knelson, an encouraging potential was shown for gravity concentration. Figure 13-4 shows the gravity recoveries obtained at SGS Lakefield.

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FIGURE 13-4     AVERAGE GRAVITY GOLD RECOVERY BY DEPOSIT USING
MOZLEY TABLE

Based on surveys and e-GRG (Extended-Gravity Recoverable Gold), Knelson performed a simulation with Rosebel data to evaluate recoveries for different scenarios and the maximum recovery achievable for different gravity throughputs. From these tests, three Falcon gravity concentrator units and an intensive leach system (Acacia) were installed.

Regarding the overall mill recovery assumed by rock type and per pit, two groups of results were used:

Whole ore leach tests on fresh ore completed in 2008 by SGS Lakefield (project 11700- 001) on 20 samples, mainly hard rock, were submitted to 48 hours of cyanidation at 45% solid (w/w) using 0.5 g/L NaCN;
     
Gravity tails leach tests completed in 2010 on 24 samples (project 12322-002), listed above, were submitted to 48 hours of cyanidation after gravity separation at 50% solid (w/w) and 0.23 g/L NaCN.

Table 13-6 summarizes the whole ore leach test results from 2008.

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TABLE 13-6     CYANIDATION TEST RESULTS (WHOLE ORE LEACH)*

  Feed NaCN 48h Gold Residue Head Gade (g/t Au)
  Size Consumption Extraction Grade    
Grade P80 µm g/t of CN Feed (%) (g/t Au) Calc. Direct
Minimum 41 0.06 91.0 0.02 0.62 0.60
Maximum 107 0.56 98.6 0.16 5.53 5.60
Average 76 0.26 95.7 0.07 1.84 1.75

*Excluding results from RH002

Figure 13-5 summarizes the overall recovery from gravity and gravity tails leach tests from the 2010 project, by rock type and Figure 13-6 summarizes the overall recoveries, per pit.

FIGURE 13-5     OVERALL AVERAGE GOLD RECOVERY BY ROCK TYPE

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FIGURE 13-6     OVERALL AVERAGE RECOVERY BY PIT

Average gold extraction for the whole ore leach tests was approximately 96% and ranged from 77.3% (Sample RH002) to a high of 98.6% (Sample S002). Nineteen of the 20 gold extraction values were 91% or higher.

In the 2010 batch tests, the recombined Knelson + Mozley tailings from each of the 24 variability samples were cyanide leached. Overall, average gold recoveries ranged from a low of 86.8%, in the case of the Koolhoven deposit, to a high of 96.3% from the Rosebel deposit. The average is 93%. Cyanide addition and consumption values were quite low and similar, regardless of the rock type or deposit. The minimum, maximum, and average cyanide addition and consumption values for the 24 variability composite tests are shown in Table 13-7.

TABLE 13-7     CYANIDE CONSUMPTION DATA

      kg of NaCN per tonne of Leach Feed    
           Overall      Hard Rock      Transition        Saprolite
  Added Cons Added Cons Added Cons Added Cons
Minimum 0.23 0.01 0.23 0.01 0.24 0.01 0.25 0.01
Maximum 0.36 0.11 0.33 0.1 0.36 0.11 0.33 0.07
Average 0.27 0.03 0.27 0.03 0.27 0.05 0.28 0.03

Based on the results obtained from the 2007 and 2010 programs, Table 13-8 shows the assumed recoveries per rock type and pit.

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TABLE 13-8     ASSUMED RECOVERIES PER ROCK TYPE AND PIT

Pit name Mill Overall Recovery (%) per rock types
  Hard Rock Transition Saprolite
East Pay Caro (EPC) 94.8 95.4 96.0
Pay Caro (PC) 96.4 95.1 93.7
Koolhoven (KH) 88.7 85.9 83.0
J Zone (JZ) 94.0 94.5 95.0
ETR 94.8 95.1 95.4
Royal Hill (RH) 96.0 96.9 97.8
Mayo (MA) 90.0 93.0 96.0
Rosebel (RB) 96.7 96.8 96.8
Roma (RM) 94.2 95.1 96.0

13.1.7

ONGOING TEST WORK

The IAMGOLD-Rosebel mine requested SGS Lakefield to update the previous CEET™ Model. Surveys are in progress, using different blends of hard rock, saprolite, and/or transition ores. The circuit will also be surveyed, in closed and open circuit, in an attempt to quantify the impact of not recirculating the pebbles to the SAG mill. The survey results will then be used to update the model. After the survey modelling, the model will be further fine-tuned through plant data reconciliation using four to six months of plant data. Finally, LOM throughput forecasting simulations will be carried out using the updated CEET™ model.

The program has been broken-down into the following steps:

  Plant data review and survey preparation;
     
  Plant audit and circuit survey;
     
  Comminution testing;
     
  Mass balances, grinding circuit modelling, and plant data reconciliation;
     
  LOM throughput forecasting simulations.

Similar to the last survey, it has been assumed that all the survey samples will be sized and the % solids will be determined at the mine site by Rosebel personnel. The following grindability tests will be performed on the selected SAG feed survey samples so that the CEET™ model can be calibrated:

  SPI test;
     
  Bond ball mill grindability test.

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SAG mill feed sample will also be submitted for the DWT, in order to model the circuit using JKSimMet in parallel. The JKSimMet model will be required to estimate the performance of the grinding circuit for the two alternative circuit configurations. The plan also investigates options to optimize the pebble crushing circuit.

Results from this work were successfully used to continuously upgrade the mill to face an increasing amount of hard rock and to optimize gold recoveries. Rosebel is regularly updating the CEET™ model in order to forecast the mill throughput as a function of the LOM.

13.2

SARAMACCA METALLURGICAL TESTING


13.2.1

INTRODUCTION

Preliminary metallurgical testing on the Saramacca deposit was performed by ALS and a summary of this program can be found in the October 2017 SRK report (SRK, 2017b). The following samples were tested:

Three composites C1 to C3 (C1 = Saprolite, C2 and C3 = Fresh Rock) were sent for sample characterization (chemical content, mineralogical content; dynamic SIMS (DSIMS) analyses, Trace Mineral Search analyses (TMS));
     
Six composites, V1 to V6, representing variability within the rock types (V1 and V2 = Saprolite, V3 and V4 = Transition, and V5 and V6 = Fresh Rock) were sent for metallurgical testing (comminution, gravity, cyanidation).

Table 13-9 summarizes the recoveries obtained from tests results performed by ALS.

TABLE 13-9     SCOPING STUDY RECOVERIES PER ROCK TYPE

  Average
Rock Type Recovery
  (%)
Saprolite 97.7
Transition 76.3
Hard Rock 81.9

The metallurgical test program for the Feasibility Study started in January 22, 2018 under the supervision of IAMGOLD. The metallurgical test plan included both composite and variability samples. The material tested was collected from both the southeast and northwest areas of the pit and from the saddle area in between. The material also covers all rock types including duricrust, laterite, saprolite, transition, and fresh rock. The test plan aimed to determine the response of Saramacca material to the existing Rosebel flowsheet and to identify any possible flowsheet modifications required to optimize recovery.

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Table 13-10 indicates the type of tests that were performed. As indicated in Table 13-10, COREM’s laboratory in Quebec City was selected to provide the majority of the metallurgical services required, with some work outsourced to SGS Lakefield. The testwork included:

  Sample and composite preparation;
     
  Head assays;
     
  Mineralogical analysis;
     
  Comminution testing:

  o Bond low energy impact test or crusher work index (CWi);
     
  o JK Drop Weight test (DWT);
     
  o SAG Pomwer Index (SPI);
     
  o SAG Mill Comminution (SMC),
     
  o Bond ball mill work index (BWi),
     
  o Abrasion index (Ai);

  Gravity testwork (e-GRG and bulk gravity tests);
     
  Leaching testwork (bottle rolls and stirred reactor testing);

  o Baseline recovery testing: whole ore leach and gravity tails leach
     
  o Preg-robbing assessment;
   
o Optimization testwork: whole ore leach at fine grind size, flotation followed by leaching of flotation products;

  Reagent optimization tests (lime consumption tests);
     
  Thickening testwork.

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TABLE 13-10     METALLURGICAL TEST PLAN

  Test Supplier
Head assays Chemical composition of samples COREM
Mineralogy Overall mineralogy and gold deportment COREM
Grinding Bond low energy impact test (CWi) COREM
  JK Drop Weight test (DWT) COREM
  SAG Power Index (SPI) SGS
  SAG Mill Comminution (SMC) SGS
  Bond Ball Work Index (BWi) COREM
  Abrasion Index (Ai) COREM/SGS
Gravity Gravity (e-GRG test) COREM
Leaching Bottle rolls, Stirred tank reactor COREM/SGS
Thickening Settling rate SGS/SNF*

Note: *SNF Floerger

Most of metallurgical test results from this FS program can be found in COREM’s report entitled “Rosebel Saramacca Metallurgical Testing for the Feasibility Study no. T2300”, (COREM, 2018).

13.2.2

FEASIBILITY STUDY SAMPLE SELECTION

The sample selection was aimed at identifying the variability response of Saramacca ore in terms of grindability and metallurgy for each of the rock types, and then to confirm the correlation of these results with composites samples.

The variability samples were selected based on lithology, gold grade, spatial distribution, and proportionally to the in-pit resources by weathering from the 2017 SRK Technical Report (SRK 2017b). Figure 13-7 illustrates the spatial localization of the variability samples within the pit shell. There are two types of variability samples:

  CM: variability samples for comminution testing (in blue)
     
  VT: variability samples for metallurgical testing (in red)

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FIGURE 13-7     SPATIAL LOCALIZATION OF THE VARIABILITY SAMPLES

In total, 23 comminution samples (CM) and 31 metallurgical samples (VT) and were selected.

For the composites, a total of six drill holes in full HQ core were dedicated to the test work. The laterite and the saprolite were only tested for the Bond ball mill work index and extractive metallurgical tests whereas the transition and fresh rock were also tested for other comminution parameters (Bond low energy, JK Drop Weight, SPI, SMC, and Bond abrasion index) and extractive metallurgical tests. The three holes located to the northwest (NW) of the pit will be used for the preparation of the four composites by rock type and the three holes located to the southeast (SE) of the pit will be used to form also four composites by rock type. Figure 13-8 illustrates the spatial localization of the composites within the pit shell.

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FIGURE 13-8     SPATIAL LOCALIZATION OF THE COMPOSITES

13.2.3

MATERIAL CHARACTERISATION


13.2.3.1

HEAD ASSAYS

Samples from both the comminution and recovery testwork (CM, VT, and composites) were submitted for head assays in order to evaluate Au, Ag, S, and graphitic carbon content as well as specific gravity. Additional chemical analyses were performed to determine elemental concentrations of Si, Al, Mg, Ca, K, Ti, Mn, P, Co, Cr, Cu, Fe, Ni, Pb, Zn, Hg, and As. The results of some elements from the analyses are presented in Table 13-11, Table 13-12, and Table 13-13.

TABLE 13-11     CM HEAD ASSAYS

Composite Rock Type Zone Au
(g/t)
Ag
(g/t)
Graphitic C
(%)
S
(%)
As
(g/t)
Fe
(%)
Al2O3
(%)
Cu
(%)
Zn
(%)
CM001 Laterite SE 2.53 - - - 806 19.30 43.0 - -
CM002 Laterite SE 0.38 0.5 0.14 - 1,120 29.50 26.9 - -
CM003 Laterite NW 0.36 - - - 371 15.60 29.1 - -
CM005 Laterite NW 0.82 - - - 974 27.40 24.2 - -
CM006 Laterite NW 0.41 - - - 178 34.90 26.2 - -
CM007 Saprolite SE 0.32 - - - 118 0.77 19.3 - -
CM008 Saprolite SE 2.15 0.6 - - 2,500 27.20 20.5 - 0.03
CM009 Saprolite SE 2.23 - - - 278 15.70 31.3 - -
CM010 Saprolite SE 5.55 - - - 969 7.42 34.0 - -
CM011 Saprolite SE 3.07 - - - 999 12.80 30.5 - -
CM012 Saprolite SE 3.78 0.3 - - 435 5.84 35.8 - -
CM013 Saprolite NW 1.57 - - - 781 6.47 16.1 - -
CM014 Saprolite NW 1.53 0.6 - - 336 18.40 25.4 - -

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Composite Rock Type Zone Au
(g/t)
Ag
(g/t)
Graphitic C
(%)
S
(%)
As
(g/t)
Fe
(%)
Al2O3
(%)
Cu
(%)
Zn
(%)
CM015 Transition SE 1.51 - - 0.9 1,890 6.06 18.1 - -
CM016 Transition NW 10.96 - - - 1,300 9.28 9.2 - -
CM017 Transition NW 4.80 - - 3.4 3,960 12.50 12.0 - -
CM018 Fresh Rock NW 1.49 - 1.05 0.6 480 9.73 12.7 - -
CM019 Fresh Rock NW 1.72 0.3 - 1.0 103 7.93 11.8 - -
CM020 Fresh Rock NW 1.15 - - 1.6 3,610 8.44 10.9 - -
CM021 Fresh Rock NW 0.64 - - 1.5 497 6.48 8.0 - -
CM022 Fresh Rock NW 5.75 0.8 - 3.9 845 7.74 7.0 - -
CM023 Fresh Rock NW 1.43 - - 1.6 144 8.65 11.5 - -

TABLE 13-12     VT HEAD ASSAYS

Composite Rock Type Zone Au
(g/t)
Ag
(g/t)
Graphitic C
(%)
S
(%)
As
(g/t)
Fe
(%)
Al2O3
(%)
Cu
(%)
Zn
(%)
VT001 Laterite SE 0.55 - - - 453 20.40 39.0 -  
VT002 Laterite SE 1.95 - 0.10 - 1,040 22.10 45.4 - -
VT003 Laterite SE 2.02 - 0.13 - 583 19.70 40.3 - -
VT004 Laterite SE 1.58 2.2 0.13 - 692 28.50 30.1 - -
VT005 Laterite SE 8.51 - 0.15 0.10 2,280 36.80 27.7 - -
VT006 Laterite NW 1.80 0.4 - - 2,100 21.10 28.3 - -
VT007 Laterite NW 2.46 0.3 - - 716 27.20 26.3 - -
VT008 Saprolite SE 0.78 - - - 839 13.70 32.5 - -
VT009 Saprolite SE 0.34 - - - 805 12.10 33.6 - -
VT010 Saprolite SE 0.82 - 0.16 - 343 6.81 9.8 - -
VT011 Saprolite SE 0.53 - - - 519 5.52 16.1 - -
VT012 Saprolite SE 2.33 - - - 370 5.83 16.9 - -
VT013 Saprolite NW 13.67 - - - 2,490 12.90 21.4 - -
VT014 Saprolite SE 1.85 0.6 - 1.10 118 6.59 18.3 - -
VT015 Saprolite NW 2.21 10.2 - - 1,600 41.20 12.5 - 0.02
VT016 Saprolite NW 0.60 - - 0.40 72 15.60 16.8 - -
VT017 Saprolite NW 0.56 - - - 757 6.35 37.0 - -
VT018 Saprolite NW 1.06 - - - 307 6.57 21.8 - -
VT019 Saprolite NW 6.35 - - - 1,560 12.40 14.2 - -
VT020 Fresh Rock SE 7.10 - - - 1,640 7.23 19.7 - -
VT021 Fresh Rock SE 0.48 - 0.17 - 249 12.30 6.9 - -
VT022 Fresh Rock NW 3.16 0.3 - 1.60 3,930 6.25 18.5 - -
VT023 Fresh Rock NW 1.19 - - 0.80 244 3.72 - - -
VT024 Fresh Rock SE 2.33 - - 0.60 309 7.95 11.5 - -
VT025 Fresh Rock NW 2.81 0.5 0.22 1.50 3,450 5.86 9.2 - -
VT026 Fresh Rock NW 1.14 - - 0.60 154 8.54 10.7 - -
VT027 Fresh Rock NW - - - - 37 8.79 11.7 - -
VT028 Fresh Rock NW 0.61 - - 0.30 90 8.48 11.3 - -
VT029 Fresh Rock NW 6.13 0.7 - 3.80 2,110 7.54 5.4 - -
VT030 Fresh Rock NW 3.60 0.8 - 4.80 1,120 9.87 8.0 - -

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Composite Rock Type Zone Au
(g/t)
Ag
(g/t)
Graphitic C
(%)
S
(%)
As
(g/t)
Fe
(%)
Al2O3
(%)
Cu
(%)
Zn
(%)
VT031 Fresh Rock NW 2.55 0.6 - 0.70 230 8.06 11.4 - -

TABLE 13-13     COMPOSITES HEAD ASSAYS

Composite Au
(g/t)
Ag
(g/t)
Graphitic C
(%)
S
(%)
As
(g/t)
Fe
(%)
Al2O3
(%)
Cu
(%)
Zn
(%)
Duricrust 1.23 1.3 < 0.1 0.1 2,290 43.2 20.3 < 0.01 < 0.02
NW LAT 0.88 1.3 < 0.1 < 0.1 833 35.3 21.7 < 0.01 < 0.02
SE LAT 2.52 1.0 < 0.1 0.1 510 21.4 39.7 < 0.01 < 0.02
NW SAP 4.83 0.9 < 0.1 < 0.1 1,270 16.3 26.1 < 0.01 < 0.02
SE SAP 0.93 0.6 < 0.1 < 0.1 330 8.7 28.8 < 0.01 < 0.02
NW TR 6.43 0.5 < 0.1 < 0.1 1,220 11.4 16.2 < 0.01 < 0.02
SE TR 2.47 < 0.3 < 0.1 < 0.1 1,840 7.6 17.8 < 0.01 < 0.02
NW HR 0.98 < 0.3 < 0.1 0.6 132 6.4 9.2 < 0.01 < 0.02
SE HR 0.07 < 0.3 < 0.1 < 0.1 101 9.8 12.9 < 0.01 < 0.02

13.2.4

MINERAL COMPOSITION AND DISTRIBUTION

Composites representing the four rock types, laterite, saprolite, transition, and fresh rock, were prepared for each of the NW and SE zones. The composites were first submitted to gravity pre-treatment using a Knelson concentrator, and the tailings were subsequently analysed to determine each sample’s mineral make-up. Table 13-14 summarizes the mineralogy of the composites’ tails.

TABLE 13-14     COMPOSITE TAILS MINERALOGY

        Mineral Proportion (%)    
Rock Type Samples Quartz Goethite Clays Micas Carbonates Sulphides Other
                 
NW LAT VT006 1 26 34 0 0 0 2
  VT002              
  VT003 0 30 68 1 0 0 1
SE LAT VT004              
  VT013              
  VT014              
NW SAP VT015 32 20 13 32 0 < 1 5
  VT018              
  VT019              
SE SAP VT012 52 6 10 27 0 0 2.5
NW TR VT022 67 1 1 22 0 2.5 6.5
  VT023              
SE TR VT020 49 6 17 26 0 0 2
  VT026              

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               Mineral Proportion (%)    
Rock Type Samples Quartz Goethite Clays Micas Carbonates Sulphides Other
  VT029 32 0 4 16 40 5 3
NW HR VT030              
  VT031              
SE HR VT024 30 2 5 20 38 1 4

Major mineral composition in each rock type gravity tails is as follows;

  Laterite: goethite, clays, micas (negligible sulphide, carbonates and quartz)
     
  Saprolite: quartz, micas, goethite, clays, (no carbonates, sulphides)
     
  Transition: Quartz, micas, clays (minimal goethite), sulphides 0-2.5%
     
  Fresh rock: carbonates, quartz, micas, minimal clays and goethite, sulphides 1-5%.

Following the overall mineralogy and the preliminary mineralogical observation on problematic cyanidation tails, the laterite and saprolite tails were submitted to the Jackson method to dissolve limonite and part of goethite using citrate to gain better access to locked gold particles. The transition and fresh rock samples were further concentrated using sulphide flotation. The flotation concentrates were further concentrated using a Mozley table.

Sulphide concentrate in transition and hard rock samples showed that the majority of Au association is with pyrrhotite (47-73%). Over 50% of the gold grains in each sample were 1-5 micron, with the balance 5-10 micron. Negligible grains (<5%) greater than 10 micron were identified after gravity pre-treatment. Figure 13-9 illustrates the gold associations in transition and fresh rock samples. Figure 13-9 summarizes the gold associations from laterite and saprolite, transition and fresh rock samples by zone. No figure has been produced for the laterite zone since only one gold grain was observed in the NW Lat zone and no gold grains were observed in the SE Lat concentrate. Figures 13-10 and 13-11 show the distribution of gold grain size for each concentrate. In concentrate, NW Sap coarse gold grains were observed (≈30 µm).

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FIGURE 13-9     GOLD ASSOCIATIONS IN CONCENTRATES BY ROCK TYPE

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FIGURE 13-10     GOLD GRAIN SIZE FOR SAPROLITE

FIGURE 13-11     GOLD GRAIN SIZE FOR TRANSITION AND FRESH ROCK

13.2.5

COMMINUTION TESTING – SARAMACCA

The results of the comminution test work for the ores are presented in Table 13-15 and the results of the comminution test work for the master composites are presented in Table 13-16. The tests conducted at COREM were not pre-screened ahead of BWi testing. Since the laterite and saprolite samples are generally soft material, only some of CM samples were selected for Bond test.

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TABLE 13-15     SUMMARY OF SMC AND BOND COMMINUTION TEST RESULTS

Composite ID Rock Type Zone SMC
(Axb)
SPI
(min)
BWi
(kWh/t)
CM-01 Laterite SE - 24.1 12.5
CM-03 Laterite SE - 1.3 4.0
CM-08 Saprolite SE - 1.0 11.5
CM-10 Saprolite SE - 0.9 1.3
CM-12 Saprolite SE - - 4.2
CM-13 Saprolite NW - - 4.2
CM-15 Transition SE 103.0 8.0 5.5
CM-16 Transition NW 78.3 16.3 10.9
CM-17 Transition NW - 37.6 10.3
CM-18 Fresh Rock NW 40.2 70.4 17.4
CM-19 Fresh Rock NW - 118.1 15.3
CM-20 Fresh Rock NW - 131.1 15.5
CM-21 Fresh Rock NW - 104.4 12.6
CM-22 Fresh Rock NW - 84.6 13.0
CM-23 Fresh Rock NW 29.5 129.1 16.3

TABLE 13-16     SUMMARY OF COMMINUTION TEST RESULTS FOR
COMPOSITES SAMPLES

Sample   BWi AI CWI SMC SPI
Rock Type Zone (kWh/t) (g) (kWh/t) (kWh/m3) (min)
Fresh Rock NW 14.1 0.148 22.5 8.7 152.9
Fresh Rock SE 13.0 0.032 12.9 8.9 85.1
Transition NW 5.6 0.0014 6.6 2.5 15.6
Transition SE 4.1 - 3.8 1.1 5.3
Laterite NW 14.1 0.0051 - - -
Saprolite SE 4.1 - - - -
Saprolite NW 7.0 - - - -

The SMC tests were conducted using particles in the -22.4/+19.0 mm particle size range. Significant variability was observed with Axb results ranging from 29.5 to 207. The SMC test results conducted at SGS Lakefield were calibrated using the JK database. In the absence of JK Drop Weight testing (DWT) results on Saramacca material, the SMC results were calibrated against the old results from a grinding survey conducted by SGS Lakefield at the Rosebel processing plant in 2009.

SPI testing was conducted on selected laterite, saprolite, transition, and fresh rock samples. The results indicated that Saramacca transition and fresh rock samples, while considered hard, are softer than the average of the existing database of Rosebel fresh rock samples tested in the past. A comparison of SPI results for Saramacca and Rosebel is shown in Figure 13-12 (ref. Report 15306-004, SGS).

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FIGURE 13-12     SPI RESULTS FOR SARAMACCA AND ROSEBEL

Based on the BWi results, the majority of laterite and saprolite samples were classified in the very soft to medium range in terms of hardness with values ranging from 1.3 -14.1 kWh/t. The transition and fresh rock values ranged from very soft at 4.1 kWh/t to hard at 17.4 kWh/t. While the saprolite and laterite samples appear to have BWi values higher than those observed in other deposits feeding RGM, it is due to the difference in test procedure used. For RGM ores, the soft material samples were soaked in water and wet-screened on a 150-mesh screen. The tests were performed on the screen oversize and the BWi were obtained on the oversize fractions are referred as “direct” BWi. The calculated overall work indices take into account the amount of fines material that was removed.

Extremely low Ai values (<0.05) were observed for the transition and fresh rock samples tested at COREM. Duplicate samples were tested at SGS Lakefield, and the results, while higher, are considered non-abrasive as the values fall below the 10th percentile threshold of the SGS Lakefield database.

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13.2.5.1

COMPARISON WITH RGM COMMINUTION VALUES

In order to evaluate the impact of introducing Saramacca material to RGM, the average comminution results from the current Saramacca test work program were compared to historical Rosebel test work reports. A comparison of the available data is presented in Table 13-17. Saramacca results are from both comminution composites (CM) and metallurgical variability samples (VT). The comparison was focussed on fresh rock, as this is the material most likely to be problematic to the operation of the crushing and grinding circuits.

TABLE 13-17     COMPARISON OF SARAMACCA AND ROSEBEL COMMINUTION
DATA FOR FRESH ROCK

        Saramacca      
Test Unit Zone Min Max Avg. RGM
  kWh/t NW 15.0 33.8 22.5  
CWi     SE   5.4   19.2   12.9 21.8
  - NW 29.5 40.2 33.8  
SMC     SE - -   30.0 33.8
  Min NW 70 153 113  
SPI     SE -   -   85 143
  kWh/t NW 12.6 17.4 14.9  
BWi     SE - -   13.0 13.4
  g NW - - 0.148  
Ai     SE - -   0.032 0.28

Based on the comminution test work conducted and the current performance of the RGM grinding circuit, there are no indications that the RGM crushing and grinding circuit will require modifications to accommodate the introduction of Saramacca material.

13.2.6

GRAVITY AND LEACHING TEST WORK


13.2.6.1

EXTENDED GRAVITY RECOVERABLE GOLD TEST (E-GRG)

The master composites for all rock types were submitted to GRG testing. The results indicated that the amount of gravity recoverable gold was not significant (low GRG) in most samples. Good GRG values were observed for the NW transition and fresh rock samples, as well as for the SE fresh rock, however, the concentrate gold grades were relatively low at 504 g/t, 32 g/t, and 9 g/t respectively. The gravity test results are presented in Table 13-18.

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TABLE 13-18     GRAVITY TEST RESULTS

      Gravity    
      Recovery    
Composite Head Grade
Measured
(g/t Au)
Head Grade
Calculated
(g/t Au)
Weight
(%)
GRG
(%)
Concentrate
Grade
(g/t Au)
Upgrade
Ratio
NW Laterite 0.33 1.06 0.22 5.0 24 22.3
SE Laterite 2.52 2.62 0.23 15.2 21 7.9
NW Saprolite 4.83 4.52 0.22 19.4 401 88.7
SE Saprolite 0.93 1.05 0.42 17.5 39 37.0
NW Transition 6.43 7.70 0.73 63.2 504 65.4
SE Transition 2.47 2.73 1.30 16.0 32 11.9
NW Fresh Rock 0.98 1.34 1.19 60.7 54 40.3
SE Fresh Rock 0.07 0.42 1.85 47.9 9 20.5

13.2.6.2

BULK GRAVITY TEST

Prior to recovery test work, the master composites were ground to 100% passing 850 micron before being submitted to a gravity pre-treatment using a Knelson concentrator. The bulk gravity test results are presented in Table 13-19.

TABLE 13-19     BULK GRAVITY TEST RESULTS

      Gravity    
      Recovery    
Composite Head Grade
Measured
(g/t Au)
Head Grade
Calculated
(g/t Au)
Weight
(%)
GRG
(%)
Concentrate
Grade
(g/t Au)
Upgrade
 Ratio
Duricrust 1.23 1.42 1.30 13.7 15.2 12.3
Nw Laterite 0.88 0.91 1.10 11.0 8.9 10.0
SE Laterite 2.52 2.52 1.20 5.5 11.2 4.4
NW Saprolite 4.83 3.77 1.20 22.9 70.7 14.6
SE Saprolite 0.93 0.96 0.70 9.0 11.8 12.7
NW Transition 6.43 7.98 1.00 28.2 218 33.9
SE Transition 2.47 2.54 0.90 6.3 18.1 7.3
NW Fresh Rock 0.98 0.80 2.50 5.7 1.8 1.8
SE Fresh Rock 0.07 0.07 1.10 1.1 0.07 1.0

Both the GRG and bulk gravity test work results showed similar trends which suggested Saramacca material is not ideally suited for gravity recovery. Some samples demonstrated a moderate level gravity recoverable gold content. In general, this was more pronounced in samples from the NW zone when compared to those from SE. Also, samples with higher head grade tended to show higher GRG values and gold upgrade ratios.

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Further testing was performed on two samples (CT-005 and CT-007) at a P80 of 75 micron and a P80 of 850 micron each. For sample CT-005, the recovery at P80 of 75 micron was slightly lower compared to the recovery at a P80 of 850 micron, however, for sample CT-007 the recovery was significantly higher at a P80 of 75 micron compared to the recovery at a P80 of 850 micron.

13.2.6.3

LEACHING TEST WORK

The leaching test work program consisted mainly of bottle roll tests conducted in duplicate at each set of test work conditions (Table 13-20). The variability samples were tested to determine their metallurgical response to whole ore leaching (WOL) as well as to cyanidation of gravity tailings. All leaching tests conducted on variability samples were conducted with carbon (10 g/L). The master composite gravity tailings were submitted to cyanidation tests with and without carbon to assess the preg-robbing tendency of the material.

TABLE 13-20     LEACHING TEST CONDITIONS

    Variability Variability – CN of Master Comp –
Test Units – WOL Gravity Tails Gravity Tails
Carbon g/L 10 10 0/30
Pulp Density % w/w   50  
Time hours   48  
Temperature oC   20-23  
NaCN initial/maintained g/L   500/350  
DO ppm   Air saturation  
pH maintained with lime     10.5-11  

13.2.6.4

WHOLE ORE LEACHING

The results of gold recovery and reagent consumption after 48 hours cyanidation are presented in Table 13-21.

TABLE 13-21     WHOLE ORE LEACH AVERAGE TEST RESULTS

        Reagent  
         Consumption  
Sample
ID
Sub-Rock Type Rock Type Head
Grade
(g/t Au)
NaCn
(kg/t)
CaO
(kg/t)
Au
Recovery
48h
(%)
VT001 Laterite Laterite 0.55 182 12,250 94.55
VT002 Laterite   1.95 312 6,470 93.33
VT003 Laterite   2.02 257 9,786 95.05

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        Reagent  
         Consumption  
Sample
ID
Sub-Rock Type Rock Type Head
Grade
(g/t Au)
NaCn
(kg/t)
CaO
(kg/t)
Au
Recovery
48h
(%)
VT004 Laterite   1.58 297 12,610 97.47
VT005 Laterite   8.51 305 10,896 96.53
VT006 Laterite   1.80 151 3,891 91.94
VT007 Laterite   2.46 210 5,514 73.98
VT008 Pillow Basalt   0.78 162 3,589 90.38
VT009 Pillow Basalt   0.34 99 4,221 85.29
VT010 Combined FB & B Fault Zone   0.82 82 3,143 87.20
VT011 Pillow Basalt   0.53 400 2,186 89.62
VT012 Pillow Basalt   2.33 117 2,852 96.14
VT013 Pillow Basalt Saprolite 13.67 149 2,632 94.55
VT014 Pillow Basalt   1.85 242 2,802 92.43
VT015 Combined FB & B Fault Zone   2.21 493 4,091 88.01
VT016 Pillow Basalt   0.60 274 3,992 91.67
VT017 Pillow Basalt   0.55 197 2,368 94.55
VT018 Pillow Basalt   1.06 265 2,522 97.17
VT019 Fault Low Grade (Fault LG)   6.35 159 2,609 95.91
VT020 Pillow Basalt   7.10 188 2,348 99.37
VT021 Fault LG Transition 0.46 160 2,340 68.48
VT022 Fault LG   3.25 349 2,822 57.54
VT023 Fault LG   1.19 108 1,645 79.83
VT024 Pillow Basalt   2.33 609 2,901 73.39
VT025 Combined FB & B Fault Zone   2.81 435 2,722 25.80
VT026 Pillow Basalt   1.14 595 2,916 86.40
VT027 Pillow Basalt   0.07 367 2,849 71.43
    Fresh Rock        
VT028 Pillow Basalt   0.61 526 1,774 79.69
VT029 Fault LG/Fault HG   6.13 295 2,367 73.65
VT030 Combined FB & B Fault Zone   3.60 421 2,290 64.44
VT031 Fault LG   2.55 422 2,750 79.61

Note. Fault LG - Fault Low Grade

The highest gold recoveries were obtained for the laterite and saprolite ores (VT001 through VT019) whereas the transition and fresh rock ores (VT020 to VT031) exhibited lower gold recoveries. The recoveries of saprolite, laterite, and transition ores tended to improve with increasing gold grade, whereas the recovery in fresh rock ores tended to worsen with the increase of gold grade.

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The results indicate that certain samples of transition zone and mainly fresh rock reveal very low recoveries indicating the presence of partial refractoriness in the ore, which is related to the gold associations with arsenopyrite, pyrite, and pyrrhotite. It was also noticed that the low recovery samples are mainly populated in fault zone particularly in the saddle zone between NW and SE.

The mineralogy suggested that the majority of the gold is fine in the Saramacca ore, and this is confirmed during the size by size analysis of gold in the whole ore leach tails which also suggests that most of the gold in the cyanidation tailings were in the -38 μm fraction (see Table 13-22). For that reason, the effect of finer grinding on the gold recovery of whole ore in variability samples VT025 and VT029 was investigated to evaluate the opportunity to increase the gold recovery in the refractory portion of the ore. The results are provided in Table 13-23.

TABLE 13-22     SIZE BY SIZE ANALYSIS OF GOLD IN CYANIDATION TAILS OF
WHOLE ORE LEACH

        Au Repartition (%)    
Rock Type Sample
ID
+ 150 µm + 106 µm + 75 µm + 53 µm + 38 µm - 38 µm
Laterite VT001 7 5 5 5 4 75
  VT002 5 3 23 12 7 50
  VT003 14 8 10 10 10 47
  VT004 6 3 7 10 11 64
  VT005 8 1 7 6 4 74
  VT006 39 7 6 5 4 38
  VT007 37 18 14 10 7 14
Saprolite VT008 58 5 4 4 3 26
  VT009 47 5 4 3 2 39
  VT010 20 9 13 12 10 36
  VT011 10 5 6 5 4 71
  VT012 21 9 6 5 1 59
  VT013 12 13 15 11 9 40
  VT014 11 2 24 17 11 36
  VT015 15 15 13 11 8 38
  VT016 11 15 16 12 7 39
  VT017 19 2 2 2 2 73
  VT018 12 6 5 4 3 70
  VT019 16 13 11 11 7 42
Transition VT020 14 6 6 6 5 62
  VT021 12 8 7 4 3 65
  VT022 9 4 16 15 11 46
  VT023 21 17 17 15 10 21

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        Au Repartition (%)    
Rock Type Sample
ID
+ 150 µm + 106 µm + 75 µm + 53 µm + 38 µm - 38 µm
Fresh Rock VT024 8 2 13 14 12 51
  VT025 4 4 10 9 6 67
  VT026 12 11 10 18 10 39
  VT027 10 4 5 6 6 69
  VT028 16 12 11 11 7 43
  VT029 21 2 22 12 8 35
  VT030 24 19 16 9 7 25
  VT031 30 18 17 9 7 19

TABLE 13-23     GOLD RECOVERY IN FINE GROUND ORES

      Au Recovery (%)
Rock Type Sample ID Head Grade
(g/t Au)
P100 = 20 µm P80 = 75 µm
Fresh Rock VT025 2.81 43.1 25.8
  VT025 2.81 42.0 25.8
Fresh Rock VT029 6.13 83.0 73.6
  VT029 6.13 82.5 73.6

Higher gold recoveries were obtained when the ores were ground finer. An average gold recovery of 42.5% and 82.75 % was obtained as compared to 25.8% and 73.6% when the grind size was P80 = 75 μm. The lower gold recovery in VT025 was attributed to its high refractoriness (arsenic and pyrite). The gold leaching kinetics suggested that for the fine ground whole ores VT025 and VT029, the majority of the gold was leached within 24 hours.

Given the positive results described above, a set of exploratory flotation tests were planned to float sulphides followed by ultrafine grinding and leaching of the concentrate to increase the recovery of the refractory portion of the Saramacca transition ore and fresh rock.

13.2.6.5

COMPOSITES LEACHED WITH AND WITHOUT CARBON

The results of the comparison of leaching with and without activated carbon are presented in Figure 13-13. The head grade of the SE (FRESH) composite was too low and the leaching with and without carbon test was not performed.

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FIGURE 13-13     GOLD RECOVERY WITH AND WITHOUT CARBON FOR THE
COMPOSITES

Following this testing it was observed that for all the tested ores types there is no clear potential for preg-robbing.

13.2.6.6

VALIDATION OF LEACHING RESULTS

In order to confirm the accuracy of the leaching test work results obtained at COREM, selected samples were sent to SGS Lakefield for replicate testing. The repeated tests included whole ore leaching of variability samples VT001, 003, 008, 011, 013, 015, 021, 025, 029, and 030 as well as leaching of Knelson tails (KT) from variability samples VT007, 010, and 022. The comparison of the COREM and SGS Lakefield results are presented in Table 13-24.

TABLE 13-24     COMPARISON OF COREM AND SGS LAKEFIELD LEACH
RESULTS

  COREM SGS Lakefield
  Head Grade (g/t Au Recovery Head Grade (g/t Au Recovery
Sample ID Au) (%) Au) (%)
VT001 0.55 94.55 0.58 93.97
VT003 2.02 95.05 2.20 95.00
VT008 0.78 90.38 0.71 88.73
VT011 0.53 89.62 0.53 88.68
VT013 13.67 94.55 8.10 89.38
VT015 2.21 88.01 2.11 85.07
VT021 0.46 68.48 0.51 67.65
VT025 2.81 25.80 2.82 26.06
VT029 6.13 73.65 5.56 61.06
VT030 3.60 64.40 3.60 65.69

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  COREM SGS Lakefield
  Head Grade (g/t Au Recovery Head Grade (g/t Au Recovery
Sample ID Au) (%) Au) (%)
KTV007 2.64 81.28 2.68 77.61
KTV010 0.81 80.27 0.79 79.75
KTV022 3.11 53.06 3.18 56.29

In general, consistency was observed between the results of the original tests performed at COREM and the replicated tests conducted at SGS Lakefield. The majority of test results were within 5% of each other with the exception of VT029. The 17% difference observed between the gold recovery results was likely due to the high head grade of the sample.

13.2.6.7

STIRRED TESTS

Stirred tank reactor leaching was performed on the whole ores of variability samples VT008, VT021, and VT029, with and without activated carbon, to investigate the variation of gold recovery between two different systems (Bottle roll vs reactor) through a better controlled air addition and DO as well as mixing in a stirred reactor. The results of this test are displayed in Table 13-25.

TABLE 13-25     GOLD RECOVERY IN STR LEACHING AND BOTTLE ROLL
COMPARISON

Sample
ID
Rock Type Head Grade
(g/t Au)
STR Recovery %
(No Carbon)
STR Recovery %
(10 g/t Carbon)
Bottle Roll Recovery %
(10 g/t Carbon)
VT008 Saprolite 0.78 89.8 88.3 90.38
VT021 Transition 0.46 39.3 67.3 68.48
VT029 Fresh Rock 6.13 64.6 73.6 73.65

VT008 yields a similar gold recovery in the presence and absence of activated carbon, showing that VT 008 does not present appreciable preg-robbing characteristics.

VT021 and VT029 samples however showed a difference of 28% and 9% in the gold recovery in the presence and absence of activated carbon, respectively. Such a difference could be explained by the presence of graphitic carbon and/or the presence of minerals with preg-robbing properties in these two samples.

No material difference was observed between the gold recovery in bottle roll and the STR cyanidation in presence of 10 g/L of activated carbon. Overall results suggest that bottle roll tests results are reliable as no potential recovery loss could be attributed to a change in leaching regime. This remains to be demonstrated for clayish laterite ore.

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13.2.7

FLOWSHEET OPTIMIZATION


13.2.7.1

FLOTATION TEST WORK

Preliminary flotation testing was performed on four samples: SE (TRANS), NW (TRANS), SE (FRESH), and NW (FRESH) composed with VT samples, in order to identify the opportunities to recover “inaccessible” gold through a potential flotation + ultrafine grinding+ cyanidation circuit. Flotation was investigated to decrease the mass pull to ultrafine grinding, which would reduce the project costs when compared with whole ore grinding.

A total of eight flotation tests and a production test were performed in order to identify the gold form in the sample sorted by ore type and location (four tests). The analysis was for each stream, separate the talc, the sulfur minerals, and the silicate minerals (four tests), and produce enough talc concentrate, sulfur concentrate, and silicate tailing to evaluate gold leaching in those three streams. The results of these eight tests are presented in Table 13-26.

TABLE 13-26     FLOTATION FLOWSHEET SUMMARY

    Talc Concentrate Sulfur Concentrate Flotation Concentrate
      Au   Au   Au
    Au Grade Recovery Au Grade Recovery Au Grade Recovery
Test No. Sample (mg/kg) (%) (mg/kg) (%) (mg/kg) (%)
1 SE Fresh - - 14.34 63.49 0.81 36.51
2 NW Fresh - - 3.78 78.02 0.66 21.98
3 NW Trans - - 7.94 46.29 7.94 43.71
4 SE Trans - - 31.45 56.16 2.59 43.84
5 NW Fresh 3.94 43.65 12.40 20.55 1.06 35.80
6 NW Trans 5.71 29.82 14.10 18.96 1.08 51.22
7 NW Trans 15.90 17.29 7.13 56.53 0.51 26.09
8 NW Fresh 6.06 40.97 8.45 39.28 0.48 19.75
Production NW Trans 14.50 17.80 5.30 60.98 0.43 21.22

As shown by the metallurgical performances of NW (TRANS) and NW (FRESH) and the production test, addition of multiple steps of activation and numerous scavenger steps improved the recovery of sulfur and gold in the sulfur concentrate. However, it was not optimized and 21.22% of the gold was left in the tailings, and optimization of gold recovery should be performed to reduce the losses. The approach taken during this test work was to float the talc and unfortunately probably lost gold units through entrainment during the flotation. Multiples steps of talc cleaning were tried in order to reduce gold units in the talc without complete success. A complete mineralogy study is currently in progress in order to understand why the flotation was not as successful as planned and to align further testing accordingly.

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13.2.8

RECOVERY

Table 13-27 shows the weighted average of recoveries per rock type and prorated with the latest mine plan.

TABLE 13-27     OVERALL RECOVERY BY ROCK TYPE FOR SARAMACCA

  Au Recovery
Rock Type Gravity + Cyanidation
  (%)
Duricrust 95.2
Laterite 93.2
Saprolite 91.0
Transition Rock 89.6
Hard Rock 74.8

It is to be mentioned that one composite sample of duricrust was tested, however, because the amount of duricrust in the total LOM is marginal. No more extensive testing was performed on this type of ore and the recovery was not deemed problematic. An overall recovery of 94%for laterite (inclusive of duricrust) was applied for the pit optimizations.

13.2.9

THICKENING TESTING

Static settling tests were conducted at SGS Lakefield on individual laterite, saprolite, and hard rock samples from both the NW and SE zones. Based on the results of flocculant screening tests, initial settling tests were done using Magnafloc 10 on all samples. Additional tests on laterite and saprolite materials were conducted with the reagent currently used at RGM – SNF Flomin AN923VHM. The clay-like nature of the laterite and saprolite makes it difficult to settle these materials. Given that the individual Saramacca rock types tested will never be fed to the RGM thickener in the absence of Rosebel material, the thickening test work program at SGS Lakefield was suspended. During a routine visit to RGM, SNF representatives conducted preliminary tests on blends of Saramacca and Rosebel material. The SNF report entitled ‘’SNF Floerger IAMGOLD Lab Evaluation’’, May 2018 reports the testing performed. Figure 13-14 summarizes the settling rate in function of different dosages of AN923VHM.

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FIGURE 13-14     TSS IN FUNCTION OF FLOCCULANT DOSAGE

The settling characteristics observed during these scoping tests confirmed that the introduction of Saramacca ore into the plant would not adversely affect thickener performance. Further testing is planned in order to verify the settling rate for additional blends between RGM and Saramacca ore.

13.2.10

REAGENT CONSUMPTION

Major consumables in the process are sodium cyanide and lime. The average cyanide and lime consumption values per rock type during leaching of the Saramacca samples are presented in Figures 13-15 and 13-16, respectively. The latter also shows the lime consumption for Saramacca vs RGM rock types.

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FIGURE 13-15     AVERAGE NACN CONSUMPTION BY SARAMACCA ROCK
TYPES

FIGURE 13-16     AVERAGE CAO CONSUMPTION OF SARAMACCA ROCK
TYPES VS RGM ROCK TYPES

Higher reagent consumptions were observed during leaching of Saramacca samples in terms of both lime and cyanide consumption when compared to RGM, however, lime consumption for laterite and saprolite were considered excessive (with some individual samples reaching 16 kg/t particularly for laterites). A series of diagnostic tests were performed to better understand this phenomenon. It was concluded that the viscosity of laterite slurries did not allow the full dissolution of lime and therefore resulted in an apparent increase in consumption. Increased cyanide consumption could be explained due to higher levels of sulphide minerals observed in Saramacca ore. Further testing is planned using mixtures of fresh rock and saprolite/laterite to improve the rheological conditions of the slurry and to better reflect the leaching environment at RGM.

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13.2.11

CONCLUSIONS AND RECOMMENDATIONS – SARAMACCA

The metallurgical results obtained during the FS program are in-line with the results in the previous program published in the SRK 2017 Technical Report (SRK 2017b) report. Comminution results, gravity, leaching, and reagent consumption are in the same range.

The FS testwork performed demonstrate lower recoveries for fresh rock and transition ore compared to the actual RGM recoveries while treated in a similar flowsheet as the existing plant. Table 13-28 summarizes the design criteria of Saramacca compared to RMG.

TABLE 13-28     COMPARISON OF MAIN DESIGN CRITERIA FOR SARAMACCA
VS RGM

    Design Criteria
Parameter Unit Saramacca RGM
Comminution Characteristics      
(Hard Rock)      
CWi kWh/t 18.6 21.8
SPI min 109 143
Axb - 32.8 33.8
BWi kWh/t 14.7 13.4
Ai g 0.09 0.28
Gold Recovery      
Laterite % 93.2 -
Saprolite % 91.0 94.4
Transition % 89.6 94.2
Hard Rock % 74.8 94.0
NaCN Consumption      
Laterite g/t 246  
       
Saprolite g/t 173 314*
Transition g/t 186  
Hard Rock g/t 417  

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    Design Criteria
Parameter Unit Saramacca RGM
Comminution Characteristics      
CaO Consumption      
Laterite g/t 9,520  
Saprolite g/t 2,919 811*
Transition g/t 2,572  
Hard Rock g/t 2,510  

Note. *The NaCN and CaO consumption rates for RGM were calculated from projected mill throughput (mix between rock types) and mill consumables presented in the RGM NI43-101 issued on September 5, 2017.

As an opportunity, additional test work is recommended to optimize metallurgical performances for each rock type. Additional tests would also help to identify problematic zones or lithologies within the deposit.

The following tests are proposed:

  Detailed process mineralogy study to better identify the gold associations and refractoriness
     
  Stirred tests
     
  Fine grinding + leaching
     
  Flotation + leaching
     
  Flotation + fine grinding + leaching
     
  Oxygen vs. Air addition to the leach
     
  Thickening on different blends
     
  P80 optimization remains in the tests proposed
     
  Blend of Rosebel and Saramacca ore
   
Test additional fresh rock samples for comminution and metallurgical response as the update LOM integrates more fresh rock compared to the previous one.

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Technical Report NI 43- 101 – November 5, 2018 Page 13-40




14

MINERAL RESOURCE ESTIMATE


14.1

SUMMARY

The consolidated Mineral Resource Statement, at September 1, 2018 for RGM and at September 13, 2018 for Saramacca, is summarized in Table 14-1 and is reported on a 100% basis. The RGM Mineral Resource estimate was prepared by, or under immediate supervision of, Raphaël Dutaut, P.Geo., an IAMGOLD employee. The Saramacca Mineral Resource estimate was prepared by, or under immediate supervision of, Dominic Chartier, P.Geo., and Oy Leuangthong, P.Eng., of SRK. Messrs. Dutaut and Chartier and Dr. Leuangthong are QPs as defined by NI 43-101.

Mineral Resources and Mineral Reserves have been prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral Resources and Mineral Reserves dated May 10, 2014 (CIM definitions).

TABLE 14-1 CONSOLIDATED MINERAL RESOURCE STATEMENT - ROSEBEL
GOLD MINE, INCLUDING SARAMACCA GOLD DEPOSIT

Deposit Classification Tonnes
(000)
Grade
(g/t Au)
Contained
Ounces (000s)
100% Basis
Attributable
Contained
Ounces (000s)
  Measured 34,216 0.6 696 661
  Indicated 261,108 0.9 7,817 7,426
RGM Measured & Indicated 295,324 0.9 8,513 8,087
  Inferred 65,154 0.9 1,797 1,707
  Indicated 27,938 2.0 1,763 1,172
Saramacca Inferred 11,824 0.7 273 182
  Measured 34,216 0.6 696 661
  Indicated 289,047 1.0 9,580 8,598
Consolidated Measured & Indicated 323,262 1.0 10,276 9,260
  Inferred 76,978 0.8 2,070 1,889

Notes:

  1.

Attributable ounces: 95% for Rosebel (excluding Saramacca), 66.5% for Saramacca.

  2.

CIM definitions were followed for classification of Mineral Resources.

  3.

Mineral Resources reported at a weighted average cut-off grade for Rosebel (excluding Saramacca) of 0.18 g/t Au for saprolite, 0.23 g/t Au for transition material, and 0.35 g/t Au for fresh rock material. Average cut-off grades for Saramacca are 0.25 g/t Au for laterite and saprolite, 0.30 g/t Au for transition material, and 0.50 g/t Au for fresh rock material.

  4.

Mineral Resources for RGM include 2018 depletion prior to September 1, 2018.

  5.

Mineral Resources are constrained within a pit shell estimated using a long-term gold price of US$1,500/oz.


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  6.

Mineral Resources are inclusive of Mineral Reserves.

  7.

Numbers may not add due to rounding.

  8.

Effective date for Rosebel (excluding Saramacca) is September 1, 2018 . Effective date for Saramacca is September 13, 2018.

The QPs are not aware of any environmental, permitting, legal, title, taxation, socio-economic, marketing, political, or other relevant factors that could materially affect the Mineral Resource estimate.

14.2

RGM CONCESSION

For the present Mineral Resource estimate, Mama Kreek (MK), East Tailing Road (ETR), and Overman (OV) block models were not updated and, as such, remain the same as the December 31, 2017 Mineral Resources.

The MK, ETR, and OV block models will subsequently be referred to as the not-updated models. The following block models have been updated and will be referred to as the updated models: Koolhoven (KH), J Zone (JZ), Pay Caro (PC), Mayo (MA), Roma West (RMW), Roma East (RME), Royal Hill (RH), and Rosebel (RB). The Mineral Resource estimate has been completed using Geovia GEMS 6.7 (GEMS) software and GSLib software using a conventional approach, including 3D geological modelling and block modelling. Two different interpolation approaches were used, depending on the area:

for MK, ETR, OV (not-updated models) : an inverse distance cubed interpolator (ID3) was used;
     
for KH, JZ, PC, RB, RH, RMW, RME, and MA (updated models): Localized Uniform Conditioning (LUC) grade estimation was performed.

14.2.1

DATABASE

The Mineral Resources at RGM are estimated using DD hole and RC hole data. All holes have been established on a local grid and the final collar locations have been surveyed and reported in UTM WGS84 zone 21N. The current Mineral Resource database is composed of 6,213 DD holes, totalling 926,533 m for 645,138 assayed samples and 31,821 RC holes, totalling 1,479,281 m for 648,491 assayed samples. The resource database includes DD holes and RC holes within and close to the pit area.

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Table 14-2 shows the drill hole data that was collected and is available in the databases for each project. From these databases, the necessary information is prepared for Mineral Resource estimation (modelling, compositing, etc.).

TABLE 14-2     DRILL HOLE DATA COLLECTION USED FOR RESOURCES
ESTIMATION

    Diamond Drill Reverse Circulation
Pit Holes (m) Intervals* Holes (m) Samples
Koolhoven 838 117,282 77,893 9 1278 639
J Zone 456 65,147 43,195 5,157 234,741 101,372
Pay Caro 1,274 214,829 152,629 6,722 337,864 159,166
Mayo 1,004 156,985 104,388 5,357 211,532 92,396
Roma 290 44,343 31,956 3,991 192,761 62,174
Royal Hill 1,087 164,528 117,298 3,920 178,768 76,373
Rosebel 806 107,713 71,766 6,640 320,660 150,618
ETR 90 12,078 8,424 - - -
Overman 250 32,167 21,810 - - -
Mama Kreek 118 11,461 15,779 25 1,677 1,086
Total 6,213 926,533 645,138 31,821 1,479,281 648,491

* Note: some intervals do not have assays results due to core loss or equivalent.

The drill hole database contains information including: collar information, downhole deviation surveys, gold assays, multi-elements-ICP assays, lithological descriptions, alteration, structural data, mineralization, major textures, specific gravity measurements, and vein descriptions.

The GEMS database validation routines were applied to the resource database. No errors were detected in the data tables. Based on this assessment, and the checks described in Section 12, it is the QP’s opinion that the drill hole database is appropriate to form the basis of the Mineral Resource estimate for the Rosebel Gold Mine.

14.2.2

GEOLOGICAL INTERPRETATION AND MODELLING

Geologic modelling work is completed using the GEMS software package.

The main lithologies, structural elements, weathering profiles, and ore zone models of each deposit are constructed using 3D outlines created on 25 m evenly spaced cross sections. The weathering profiles, which include saprolite, transition, and rock are determined using geotechnical measurements taken on the core by the geotechnicians and geologists. The laterite profile is determined using geological observations of the core samples by the geologists and from the topography; it is generally modelled as a layer thinner than 5 m.

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Ore zone modelling is strongly guided by a project’s geological model and refers to lithological units, structural, and deformation constraints. Generally, ore zone envelopes are drawn from drill data assays which carry a gold content higher than 0.3 g/t Au. Ore zones must be at least 4 m thick in saprolite and at least 5 m thick in transition and rock; except for the Mayo deposit where a 3 m minimum thickness may occur in some areas. From the 3D rings drawn on the sections, surfaces and solids are built and validated. For deposits with production data available (Koolhoven, Pay Caro, J Zone, Mayo, Roma, Rosebel, and Royal Hill), the ore zone modelling might also consider blast hole results for geometrical purposes. The ore zone model for the Northern deposits (KH, JZ, PC, and ETR) is presented in Figure 14-1.

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14.2.3

SPECIFIC GRAVITY

In-situ bulk density samples are taken from DD holes for each weathering type (laterite, saprolite, transition, and rock) and for specific lithology units in each project. The density is calculated by the RGM laboratory by using the wax method for soft and transitional material.

Over 18,000 specific gravity measurements were used to assign densities for the various rock types and alteration profiles. Table 14-3 presents the in-pit average densities, by material type, for the actual resources.

TABLE 14-3     RGM RESOURCES – BULK DENSITY DATA

 Average Resources density by material type 
Pit Laterite Saprolite Transition Hard Rock
Koolhoven/Bigi 1.73 1.74 2.29 2.70
J Zone 1.73 1.73 2.32 2.71
Pay Caro 1.68 1.79 2.35 2.78
Mayo 1.73 1.73 2.23 2.74
Roma East 1.72 1.76 2.34 2.69
Roma West 1.73 1.74 2.29 2.70
Royal Hill 1.71 1.70 2.35 2.78
Rosebel 1.67 1.76 2.36 2.70
Overman 1.87 1.72 2.30 2.66
East Tailings Road 1.73 1.79 2.31 2.79
Mama Kreek 1.66 1.71 2.30 2.80

14.2.4

COMPOSITING, STATISTICS, AND CAPPING


14.2.4.1

NOT-UPDATED BLOCK MODELS

Three metre composites are generated from DD hole uncapped assays for ETR, MK, and OV.

The choice of composite length is mainly based on the following criteria: height of mining bench, ore zone thickness, length of assays, and reconciliation with production numbers. All composites are constrained within the ore zone and laterite solids first, and secondly, within the lithology and weathering solid limits. Poorly representative composites are not taken into consideration for resource estimation. These can include composites which are missing more than 50% of assays and/or where the composites that are less than 1 m (for 5 m composites) or 0.6 m (for 3 m composites). The smaller composites have possibly been created at the end of a solid interval or at the bottom of a hole. They are discarded from the composite data set.

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The Mamakreek deposit differs from that last rule on the minimum length of a composite. In order to ensure representative composites, if the last interval is less than the composite length, the composite length is adjusted to make all intervals equal. For this deposit, all composites, constrained in the ore zones, are used unless they are missing more than 50% of the assays.

14.2.4.2

UPDATED BLOCK MODELS

For DD holes, 3 m composites are created based on capped assays. Composites are created from collars to toes respecting the Ore zone contacts. For RC holes, 2 m assays are not composited.

The composite length of a DD hole is selected to approximately align with the volume of 2 m RC hole samples. The DD hole composite interval is assigned a null value if non-null samples account for less than 20% of its length (i.e. 0.6 m).

14.2.5

STATISTICS COMPOSITES

Gold grade statistics, from the set of composites, are calculated using GEMS Geostatistical module or GSlib-type software. Statistics for raw assays and composites, used during estimation, are presented in Table 14-4 for RC holes and Table 14-5 for DD and exploration RC hole data used. The two limits (High Grade Limit and High Grade Transition Limit) that are used in the treatment of high grade results (see Section 13 - Ongoing Test Work for details) during resource estimation are determined from these statistics. The first one, the High Grade Limit, corresponds to outliers observed in histogram plots. The second one, the High Grade Transition Limit, corresponds to inflection points representing different grade domains on the curve of cumulative probability plots.

TABLE 14-4     GRADE CONTROL REVERSE CIRCULATION DRILLING - ASSAYS
STATISTICS

Pit Type Capping
applied
to
Capped
at
Number Capped
n (%)
Raw
Mean
Raw SD Cap
Mean
Cap SD.
  Raw Assays     100,178   0.454 2.993 0.403 1.041
KH-J Zone                  
  Composites Assays 12 100,178 0.26     0.496 1.149
  Raw Assays     147,087   0.278 1.969 0.26 0.69
Pay Caro                  
  Composites Assays 12 147,087 0.08     0.258 0.66
  Raw Assays     92,386   0.402 2.464 0.365 0.986
Mayo                  
  Composites Assays 12 92,386 0.23     0.365 0.986

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Technical Report NI 43- 101 – November 5, 2018 Page 14-7




Pit Type Capping
applied
to
Capped
at
Number Capped
n (%)
Raw
Mean
Raw
SD
Cap
Mean
Cap SD.
Roma - Raw Assays     48,143   0.225 1.95 0.194 0.641
East Composites Assays 10 48,143 0.17     0.25 1.95
Roma - Raw Assays     14,030   0.395 2.177 0.33 0.937
West Composites Assays 9 14,030 0.46     0.354 1.2
  Raw Assays     76,373   0.37 2.426 0.317 1.03
Royal Hill                  
  Composites Assays 11 76,373 0.37     0.317 1.03
  Raw Assays     110,028   0.463 6.39 0.403 1.07
Rosebel                  
  Composites Assays 10 110,028 0.4     0.403 1.07

TABLE 14-5     DIAMOND DRILL HOLE AND EXPLORATION REVERSE
CIRCULATION DRILLING - ASSAY STATISTICS

Pit Type Capping
applied
to
Comps
Length
(m)
Capped
at
Number Capped
n (%)
Raw
Mean
Raw
SD
Cap
Mean
Cap
SD
  Raw Assays     - 109,994 - 0.206 1.335 0.195 0.927
KH-J Zone                    
  Composites Assays 3 22 53,323 0.07     0.197 0.693
Pay Caro Raw Assays     - 159,378 - 0.26 1.638 0.234 0.898
  Composites Assays 3 11 74,369 0.29     0.239 0.72
Mayo Raw Assays     - 104,388   0.22 4.45 0.182 0.815
  Composites Assays 3 16 50,751 0.19     0.186 0.63
Roma - East Raw Assays     - 12,917 - 0.092 0.864 0.085 0.499
  Composites Assays 3 20 6,090 0.05     0.085 0.36
Roma -                    
West Raw Assays     - 19,096   0.153 1.992 0.126 0.797
  Composites Comps 3 20 8,882 0.1     0.125 0.564
Royal Hill Raw Assays     - 113,690 - 0.265 3.312 0.227 1.171
  Composites Assays 3 20 52,748 0.21     0.228 0.834
Rosebel Raw Assays     - 71,458 - 0.224 1.542 0.206 0.907
  Composites Assays 3 18 35,487 0.11     0.207 0.664
ETR Raw Assays     - 1,685       0.61 11.11
  Composites Comps 3 9** 1,081 0.55     0.45 2.04
Overman Raw Assays     - 3,927 -     0.73 6.36
  Composites Comps 5 6** 1,136 0.44     0.63 1.27
Mama Kreek Raw Assays     - 2,130       0.35 5.35
        Varying            
  Composites Assays 3 (1 to 6) 1,037       0.26 0.64

* Laterite composites were capped at 3 g/t ** Laterite composites were capped at 4 g/t SD – Standard Deviation

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Technical Report NI 43- 101 – November 5, 2018 Page 14-8




14.2.6

BLOCK MODEL PARAMETERS

For each pit, block models are created and interpolated using the GEMS software package for the not updated block models while interpolation was run using GSLib-style scripts for the newly updated models. Block size properties and extensions are selected to cover all the interpreted Ore zones and in accordance with RGM mining equipment and practices. Block model properties are presented in Table 14-6.

All block models are coded for Lithologies, Alterations (Weathering), and Ore zones (mineralized area) using a unique rock code assigned when at least 50% of the blocks are located inside a solid.

TABLE 14-6     BLOCK MODELS PROPERTIES

    Origin     Size   Number of block
Pit X Y Z Orient.* Column Row Level Column Row Level
KH-JZ 46,181 88,486 670 -18 10 4 4 500 413 144
Pay Caro 47,335 86,843 700 -18 10 4 4 400 492 175
Mayo 42,600 80,400 580 0 10 4 5 370 393 116
Roma-East 47,300 81,050 602 0 10 4 4 150 313 138
Roma-West 46,575 80,643 602 30 10 5 6 140 220 91
Royal Hill 48,650 80,400 580 0 10 4 4 310 550 150
Rosebel 56,800 80,700 598 0 10 4 6 425 369 100
ETR 51,766 85,533 700 -18 10 4 4 140 175 150
Overman 47,367 102,657 620 -26 10 5 5 400 165 60
Mama Kreek 57,000 86,250 650 -15 10 5 6 313 240 100

* Using Gems ZXZ rotation system

14.2.7

NOT-UPDATED BLOCK MODELS

Block models for East Tailing Road (ETR), Overman, (OV), and Mama Kreek (MK) were not updated recently. The last block model updates for these deposits vary from 2014 to 2017. It was considered appropriate to not update these block models as no major new drilling was completed nor was mining information added to these deposits.

Interpolations are performed in GEMS software using a conventional anisotropic ID3 interpolation. The Au grade estimates are generally generated from 5 m composites (OV) or 3 m composites (ETR, and MK). To avoid smearing gold grades from one mineralized zone to another or into the host rock, geologic and mineralized contacts were considered as hard boundaries.

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Technical Report NI 43- 101 – November 5, 2018 Page 14-9



A three pass interpolation strategy is performed with relaxing search parameters. The first pass ellipse size was generally about 50 m in the two main directions and 25 m in the minor direction. The second pass is selected as 75 m in the major and the intermediate direction and as 37.5 m in the minor direction. The third pass is set as the double of the second pass. Ellipsoid directions were orientated according to the interpreted mineralized ore zones or the main grade orientation (ore shoot). A spherical search method is preferred to interpolate for:

  Lateritic part of each deposit to follow the original topography of the deposit.
     
  ETR deposit due to the folding shapes of the ore zones.

Interpolation is performed using ID3, with a maximum number of composites varying by pit from 12 to 20 in order to control smoothing. For each pass, the minimum number of composite is decreased to increase the number of blocks estimated. A maximum of two or three composites, from the same hole, is set to limit grade smearing. The parameters used to estimate gold grade in the block models are shown in Table 14-7.

TABLE 14-7     DETAILED BLOCK MODEL PARAMETERS.

  Interpolation parameters - ID3  
  Composites   Ellipse average ranges
  Min   Max Restricting      
Pit (Pass1- Max per    search Pass1 Pass2 Pass3
  P2-P3)   hole grade      
ETR 1 - 5 - 8 20 3  None 50/50/50 75/75/75 150/150/150
Overman 1 - 3 - 5 12 3  None 50/20/50 75/25/75 150/50/150
Mama Kreek 1 - 4 - 7 20 3  None 50/25/50 75/37.5/75 150/75/150

14.2.8

UPDATED BLOCK MODELS

Koolhoven (KH), J Zone (JZ), Pay Caro (PC), Rosebel (RB), Royal Hill (RH), Roma West (RMW), Roma East (RME) and Mayo (MA) were updated with the latest drilling and mining information; databases were closed as of December 31, 2017. For these deposits, the interpolation approach was developed with support from Clayton V. Deutsch Consultants Ltd (CVDC), an independent consulting firm based in Edmonton, Alberta (Canada).

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Technical Report NI 43- 101 – November 5, 2018 Page 14-10



The same geostatistical approach developed during previous estimate (NI43-101, September 5th, 2017) was used, consisting of a kriging or co-kriging of panel followed by a Localized Uniform Conditioning (LUC) support correction. These well-known geostatistical methods were used in an effort to better reflect the production reconciliation history of RGM and to incorporate new RC exploration and definition holes drilled since 2015.

In addition to the lithological and alteration (weathering) interpretation, a new sub-model was created to reflect the two different data types (DD and RC) and data spacing: grade control tight spacing (generally at 10 m by 5 m or 12 m by 6 m) and exploration-definition relatively sparse spacing (generally around 50 m by 50 m). In this approach all blocks were interpolated (inside and outside Ore zones). A total of five different geostatistical domains were defined and used for interpolation.

Model 1 includes blocks within approximately 12 m from RC grade control data. These holes are generally shallow (40 m to 70 m deep) and as such represent only the upper portion of the new resources.
     
Model 2 includes blocks situated within the Ore zones and at a maximum distance of 20 m from RC holes.
     
Model 3 includes blocks located outside of the Ore zones and at a maximum distance of 5 m from RC holes.
     
Model 4 includes blocks situated within the Ore zones not within the 20 m buffer from RC holes (model 2).
     
  Model 5 includes all other blocks at a maximum distance of 200 m to Ore zones or hole.

Although the vast majority of the blocks were flagged as model 5, model 5 represents only a negligible percentage of the resources (metal) above cut-off. Most blocks classified as model 5 are either not classified or assigned the Inferred category. Most of the metal is within model 1 (grade control area) and model 4 (within interpreted Ore zones wireframes).

In order to take into consideration the two different types of data at different positions (heterotopic), an Ordinary Co-Kriged (OCK) interpolation was performed using RC hole assays (2 m) and DD hole composites (3 m). As RC holes returned possibly more consistent grade than DD holes, a trend model was first built using a moving windows average method for models 1, 2, and 3; this trend model emphasized the RC holes compared to the DD holes.

The OCK was performed using a minimum of one and a maximum of data points varying between 12 and 64, although an ellipse size is selected in order to ensure that virtually all blocks were estimated with 12 composites. Table 14-8 presents the estimation parameters used during interpolation.

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Technical Report NI 43- 101 – November 5, 2018 Page 14-11



TABLE 14-8      ESTIMATION PARAMETERS USED DURING INTERPOLATION

Model 1, 2, 3

Parameter MA RB RH RMW PC JZ-KH
DDH Cap 12 10 11 16 10 12
Secondary search Y Y Y Y Y Y
Secondary cap 7 5 5 11 2 5
Secondary radius 6 8 6 5 4 8
Use trend Y Y y Y Y Y
Max data for kriging 12 24 24 12 12 12
Enforce panel grades in LUC Y N N N N N
SMU X,Y,Z 6,5,4 8,5,8 8,8,4 8,8,6 6,5,4 6,5,4
Nugget Effect (Model 1) 0.6 1 1 0.6 0.5 0.5
Nugget Effect (Model 2) 0.6 1 1 0.6 0.45 0.5
Nugget Effect (Model 3) 0.6 1 1 0.6 1 1

Model 4 and 5

Parameter MA RB RH RMW PC JZ-KH
DDH Cap 16 25 20 20 11 22
Secondary search N N N Y N N
Secondary cap       20 10  
Secondary radius Use trend N N N 20 Y 10 Y N
Max data for kriging (Model 4) 12 48 48 64 48 12
Max data for kriging (Model 5) 12 12 12 36 12 12
Enforce panel grades in LUC Y N N Y N N
SMU X,Y,Z 10,10,8 8,5,8 8,8,4 10,10,6 10,8,8 10,6,4
Nugget Effect (Model 4) 0.4 1 1 0.3 0.3 0.2
Nugget Effect (Model 5) 0.2 0 0 0.3 0 0

Kriging is applied to panels of 40 m by 40 m by level height (4 m to 6 m as reported in the block property table). Localized Uniform Conditioning (LUC) is then performed using an effective SMU size of 6 m by 5 m by 4 m for MA, RH, RME, PC, JZ, KH, 8 m by 5 m by 8 m for RB and 10 m by 10 m by 8 m for RMW.

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Technical Report NI 43- 101 – November 5, 2018 Page 14-12



In order to perform OCK, a set of three different variograms were produced: one for RC holes only, one for DD holes only, and one cross-variogram for combined RC-DD data. The variography exercise was performed on back-transformed Normal Score experimental variograms. 3D variogram models are fitted in three directions (major, semi-major, and minor) following the geological understanding. Examples of variogram models used at Rosebel, Royal Hill, and Pay Caro for model 4 (DDH only) are presented in Figure 14-2.

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Technical Report NI 43- 101 – November 5, 2018 Page 14-13



FIGURE 14-2      DDH VARIOGRAM MODELS USED FOR MODEL 4

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Technical Report NI 43- 101 – November 5, 2018 Page 14-14




14.2.9

BLOCK MODEL VALIDATION

As part of the validation process, a number of different interpolation runs were completed using various search strategy, number of composites, and alternative capping values. Alternative interpolation methods (Inverse Distance Squared, Ordinary Kriging, and Uniform Conditioning) were also used. The results of these runs were visually, statistically, and graphically compared (grade tonnage curves).

Other validation steps included:

 

Comparison of the 3D volumes and block model volumes;

     

Comparison of the basic statistics for assays, composites, and block model for each domain;

     

Verification of rock code flagging in block model attributes for consistency with 3D wireframes;

     
 

Visual check of variogram orientation along known geological features;

     
 

Naïve Cross-validation (block grade compared to input conditioning data);

     
 

Cumulative distribution function comparison of LUC to DGM methodology;

     
 

Comparison with previous grade control production data;

     
 

Visual check of the block and composite grades in plans and sections view.

Swath plots were compiled on vertical sections and plan views to check the consistency of the interpolation. For the updated block models, values were compared with cell-declustered data, Nearest Neighbour model (NN). No pits were used to constrain the data as swath plots are designed to check the overall quality of an estimate.

Figure 14-3 presents the swath plots for the Royal Hill block model. In general, the LUC model is shown to reproduce the overall trend of the declustered data. The declustered data is more variable due to the relatively limited amount of data that occurs in some bins (particularly near the edges of each plot), however, its overall trends are well reproduced.

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Technical Report NI 43- 101 – November 5, 2018 Page 14-15



FIGURE 14-3      SWATH PLOTS FOR ROYAL HILL BLOCK MODEL

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Technical Report NI 43- 101 – November 5, 2018 Page 14-16




14.2.10

WHITTLE OPTIMIZATION

Conceptual mining parameters used to generate the Mineral Resource (Whittle) shells for the various RGM deposits are presented in Section 15.

14.2.11

CLASSIFICATION

The Mineral Resources estimations for all projects are classified according to the CIM definitions. Detailed parameters used in the estimation of each resource category are presented in Table 14-6.

Measured. Blocks estimated using grade control data (model 1) were classified as Measured; blocks inside a 5 m by 10 m or 6 m by 12 m drill hole spacing pattern.

   

Indicated. All blocks from modelss 2 and 3 were coded as Indicated, as they are within 5 and 20 m respectively from an RC hole. Blocks from model 4 were classified as indicated if a minimum of four data points from a minimum of two different holes were found within an ellipsoid of 75-50- 25 m.

   

Inferred. Blocks from models 4 and 5 were classified as inferred if at least one assay (RC or DDH) was found within an ellipsoid of 100-50-25 m.


14.2.12

MINERAL RESOURCE REPORTING

Excluding the Saramacca deposit, the Mineral Resource estimate at September 1, 2018 is 295 Mt at an average grade of 0.9 g/t Au, containing 8.513 Moz in the Measured and Indicated category. There is an additional 65 Mt at an average grade of 0.9 g/t Au, containing 1.789 Moz in the Inferred category.

Table 14-9 presents the Mineral Resource estimation at RGM as of September 1, 2018. This Mineral Resource is estimated within pit shells optimized at a US$1,500/oz Au price and corresponding cut-off grades and includes the Measured, Indicated, and Inferred Mineral Resource categories. A volumetric analysis using GEMS is performed to determine the tonnage and grade of the Measured, Indicated, and Inferred Mineral Resources (MI+I) inside each of these shells. The stockpile inventory is classified as Measured and is included in the total.

The consolidated RGM Mineral Resource Statement is presented in Table 14-1.

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Technical Report NI 43- 101 – November 5, 2018 Page 14-17



TABLE 14-9      RMD MEASURED, INDICATED, AND INFERRED MINERAL RESOURCE ESTIMATION AS OF SEPTEMBER 1, 2018
Rosebel Gold Mines N.V. - 100% Basis

Measured Mineral Resources - September 1st, 2018 (Inside pit shell)
$1,500 / ounce


Deposit
Cut-off Grade (g/t Au) Laterite Saprolite Transition Rock Total
Laterite & Transition Hard Rock Tonnes Au Au Tonnes Au Au Tonnes Au Au Tonnes Au Au Tonnes Au Au
Saprolite (000) (g/t)  (000 oz)   (000)  (g/t) (000 oz) (000)   (g/t)  (000 oz)  (000) (g/t)  (000 oz)  (000) (g/t)  (000 oz) 
Koolhoven/Bigi 0.18 0.23 0.34 - - - - - - - - - - - - - - -
J Zone 0.18 0.23 0.34 16 0.5 0 37 0.4 0 2,572 0.7 54 3,222 0.9 91 5,847 0.8 146
Pay Caro & East Pay Caro 0.17 0.23 0.34 22 0.3 0 373 0.4 4 2,451 0.5 37 1,757 0.7 38 4,603 0.5 79
Mayo 0.18 0.23 0.34 - - - 3 0.5 0 54 0.6 1 1,485 0.7 34 1,542 0.7 35
Roma West 0.18 0.24 0.35 - - - 96 0.4 1 284 0.4 4 751 0.7 16 1,131 0.6 21
Royal Hill 0.19 0.23 0.34 - - - 81 0.4 1 230 0.5 4 2,741 0.8 74 3,052 0.8 79
Rosebel 0.20 0.25 0.36 2 0.3 0 342 0.4 4 285 0.5 5 1,609 0.9 44 2,238 0.7 53
TOTAL       39 0.4 0 932 0.4 11 5,877 0.6 105 11,565 0.8 296 18,413 0.7 413
                                     
Stockpiles                               15,803 0.6 283
                                     
GRAND TOTAL Measured Resources 39 0.4 0 932 0.4 11 5,877 0.6 105 11,565 0.8 296 34,216 0.6 696

Indicated Mineral Resources - September 1st, 2018 (Inside pit shell)
$1,500 / ounce

  Cut-off Grade (g/t Au) Laterite Saprolite Transition Rock Total
Deposit Laterite & Transition Hard Rock Tonnes   Au Au Tonnes  Au Au Tonnes Au   Au Tonnes Au Au Tonnes Au Au
  Saprolite (000) (g/t)  (000 oz)  (000)   (g/t) (000 oz) (000)    (g/t) (000 oz)    (000) (g/t) (000 oz)    (000) (g/t) (000 oz)  
Koolhoven/Bigi 0.18 0.23 0.34 98 0.5 2