e6vk
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549
FORM 6-K
Report of Foreign Private Issuer
Pursuant to Rule 13a-16 or 15d-16 Under
the Securities Exchange Act of 1934
For the month of March, 2006
Cameco Corporation
(Commission file No. 1-14228)
2121-11th Street West
Saskatoon, Saskatchewan, Canada S7M 1J3
(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.
Indicate by check mark whether the registrant by furnishing the information contained in this Form
is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the
Securities Exchange Act of 1934.
If Yes is marked, indicate below the file number assigned to the registrant in connection with
Rule 12g3-2(b):
Exhibit Index
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Exhibit No. |
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Description |
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Page No. |
1.
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Kumtor Gold Mine Technical Update Report dated
March 9, 2006 |
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SIGNATURE
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.
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Date: March 13, 2006
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Cameco Corporation |
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By: |
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Gary M.S. Chad |
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Gary M.S. Chad |
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Senior Vice-President, Governance, |
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Legal and Regulatory Affairs, and |
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Corporate Secretary |
TECHNICAL UPDATE REPORT
on the
KUMTOR GOLD MINE
KYRGYZ REPUBLIC
for
CENTERRA GOLD INC.
and
CAMECO CORPORATION
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March 9, 2006
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Henrik Thalenhorst, P. Geo. |
Toronto, Canada
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Strathcona Mineral Services Limited |
TABLE OF CONTENTS
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1. SUMMARY |
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1 |
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1.1 Kumtor Gold Project |
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1 |
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1.2 Arrangements with the Kyrgyz Republic |
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1 |
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1.3 Property Location and Description |
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2 |
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1.4 Kumtor Geology and Mineralization |
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2 |
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1.5 Mining Operations |
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3 |
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1.6 Mineral Reserves and Resources, Year-End 2005 |
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4 |
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1.7 Potential for Mineral Reserve Additions |
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1.8 Projected Economic Performance |
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6 |
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2. INTRODUCTION |
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2.1 Background |
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2.2 Terms of Reference |
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9 |
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2.3 Sources of Information |
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2.4 Reliance on Other Experts |
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11 |
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3. PROPERTY DESCRIPTION AND LOCATION |
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11 |
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4. ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY |
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18 |
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5. HISTORY |
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5.1 Exploration History |
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5.2 Mineral Reserves History |
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21 |
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5.3 Production History |
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23 |
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6. GEOLOGICAL SETTING |
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24 |
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7. DEPOSIT TYPE |
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32 |
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8. MINERALIZATION |
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32 |
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8.1 General Description |
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32 |
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8.2 The Kumtor Deposit |
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33 |
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8.3 The Southwest Deposit |
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34 |
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8.4 The Sarytor Deposit |
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35 |
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9. DRILLING |
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35 |
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10. SAMPLING METHOD AND APPROACH |
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36 |
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10.1 Historical Methods |
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36 |
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10.2 KOC Methodology |
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36 |
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11. SAMPLE PREPARATION, ANALYSES AND SECURITY |
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37 |
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11.1 Historical Methods |
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11.2 KOC Methodology |
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11.3 Conclusion on Sampling and Analytical Protocols |
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12. DATA VERIFICATION |
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41 |
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13. ADJACENT PROPERTIES |
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14. MINERAL PROCESSING AND METALLURGICAL TESTING |
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15. MINERAL RESOURCE AND MINERAL RESERVE ESTIMATES |
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15.1 General |
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15.2 Geological Modelling |
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15.3 Block Models |
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15.3.1 The Kumtor KS-6 Model |
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15.3.2 Southwest and Sarytor Block Models |
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15.4 Resource Classification |
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15.5 Mineral Reserve Estimation |
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46 |
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15.6 Dilution Provisions |
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15.7 Economic Pit Design Parameters |
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15.8 Pit Wall Stability and Pit Design Parameters |
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15.9 Waste Dump Design |
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15.10 The Davidov Glacier |
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15.11 December 31, 2005 Mineral Reserve Estimate |
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15.12 Accuracy of Resource and Reserve Estimates |
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15.12.1 Comparison with Polygonal Approach |
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15.12.2 Reconciliation to Mill Feed |
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15.13 Life-of-Mine Plan |
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16. POSSIBLE MINERAL RESERVE ADDITIONS |
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16.1 Kumtor and Southwest Pit Extensions |
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16.2 Underground Mining |
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16.2.1 Obligation to Evaluate Underground Mineral Reserves |
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16.2.2 Underground Mineral Resources |
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70 |
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16.3 Other Target Areas |
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16.3.1 Northeast Area |
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16.3.2 Bordoo Area |
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16.3.3 Akbel Area |
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16.4 Planned 2006 Exploration Expenditures |
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73 |
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17. ADDITIONAL INFORMATION FOR PRODUCTION PROPERTIES |
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73 |
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17.1 Mining Operations |
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17.2 Grade Control |
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75 |
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17.3 Mineral Processing |
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77 |
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17.4 Tailings Management Facility |
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80 |
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17.5 Maintenance and Services |
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81 |
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17.6 Human Resources |
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82 |
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17.7 Permits and Licences |
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83 |
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17.8 Environmental Management System |
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84 |
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17.9 Environmental Management Action Plan |
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17.10 Closure Provisions |
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17.11 Occupational Health and Safety |
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88 |
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17.12 Gold Sales |
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89 |
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17.13 Taxation |
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90 |
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17.13.1 Corporate Profit Tax |
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90 |
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17.13.2 Value Added Tax |
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91 |
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17.13.3 Other Taxes |
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91 |
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17.14 Historical Operating Cost Performance |
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91 |
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17.15 Capital and Operating Cost Estimates |
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93 |
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17.16 Financing |
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93 |
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17.17 Economic Analysis |
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97 |
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18. INTERPRETATION AND CONCLUSIONS |
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100 |
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19. RECOMMENDATIONS |
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101 |
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20. REFERENCES |
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103 |
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21. DATE AND SIGNATURE PAGE |
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107 |
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CERTIFICATE |
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LIST OF FIGURES
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Figure |
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1 Project Location and Geotectonic Framework |
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12 |
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2 Location and Access |
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13 |
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3 Concession Area and Site Map |
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15 |
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4 Geological Surface Map, Kumtor Area |
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26 |
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5 Geological Map, 3800 Level, Central Block, Southwest and Sarytor Areas |
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27 |
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6 Schematic Geological Section, Kumtor Line 122 |
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7 Schematic Geological Section, Kumtor Line 18 |
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8 Schematic Geological Section, Southwest Deposit Line 3170 |
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9 Schematic Geological Section, Sarytor Deposit Line 156 |
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10 Ultimate Pit Design and December 2005 Pit |
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11 Block Model Section, Kumtor Line 122 |
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12 Block Model Section, Kumtor Line 18 |
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13 Block Model Section, Southwest Deposit Line 3170 |
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14 Block Model Section, Sarytor Deposit Line 156 |
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60 |
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15 Longitudinal Section showing Ultimate Pit and Additional Resources |
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68 |
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16 Mill Flowsheet |
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78 |
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17 Cash Flow Sensitivities |
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99 |
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LIST OF TABLES
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Table |
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1 Coordinates of Kumtor Mining Concessions |
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16 |
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2 Summary of
Additional Drilling Completed, 1998 2005 |
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21 |
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3 Kumtor
Deposit History of Mineral Reserve Estimates |
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22 |
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4 Kumtor Production History |
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24 |
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5 Coarse Reject Check Assay Results (>0.1 g/t Gold) |
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40 |
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6 Comparison of KS-6 Model with and without External Dilution |
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48 |
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7 Kumtor and Southwest Economic Pit Design Parameters |
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49 |
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8 Ultimate Kumtor Pit Design Parameters |
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51 |
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9 Southwest Pit Design Parameters |
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53 |
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10 Kumtor Mineral Reserves at December 31, 2005 |
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56 |
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11 Reconciliation of KS-5 and KS-6 Models with Ore Mined and Milled |
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63 |
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12 Life-Of-Mine Plan and Production Forecast |
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65 |
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13 Kumtor Mineral Resources in Addition to Mineral Reserves |
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67 |
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14 Mineral Resources Considered for Underground Mining |
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70 |
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15 Major Pit Equipment Additions and Deletions, 2006 to 2012 |
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75 |
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16 Material Destination by Grade and Type |
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76 |
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17 Summary of Kumtor Personnel, December 31, 2005 |
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82 |
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18 Kumtor Personnel, 2006 to 2012 |
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82 |
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19
Historical Operating Costs, 1997 2005 |
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92 |
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20 Projected
Operating Costs, 2006 2013 |
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94 |
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21 Projected
Capital Costs, 2006 2013 |
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95 |
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22 Projected
Mine Net Cash Flow, 2006 2013 |
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96 |
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23 NPV of
Mine Net Cash Flow 2006 2013 |
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98 |
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1. SUMMARY
1.1 Kumtor Gold Project
The Kumtor gold project in the Kyrgyz Republic has been one of the most successful mine
developments in the mining industry in recent years. The project originated in 1992 when
Cameco Corporation (Cameco), while pursuing uranium prospects in the Kyrgyz Republic, was
presented with an opportunity to follow up on the discovery of gold at Kumtor in 1978 and
subsequent extensive exploration work by the USSR Ministry of Geology when the Kyrgyz
Republic was part of the former Soviet Union. The Kumtor gold project is now one of the
largest gold mines in the world, having produced between 500 000 and 750 000 ounces of gold
per year at an average cash cost of US$193 per ounce during the nine-year period from 1997
to 2005.
1.2 Arrangements with the Kyrgyz Republic
In December 1992, Cameco signed an initial agreement with the Government of the Kyrgyz
Republic giving Cameco the exclusive right to evaluate and develop the Kumtor project. In
December 1993, Kilborn Western Inc. (Kilborn), (now SNC-Lavalin Inc.), completed a
feasibility study on the project, which was amended in 1994 and 1995 (Kilborn Feasibility
Study). A final project development agreement was concluded with the Government of the
Kyrgyz Republic in May 1994 under which Cameco, through its wholly-owned subsidiary Kumtor
Mountain Corporation (KMC), acquired a one-third interest in Kumtor Gold Company (KGC), the
project owner. The remaining interest was held by Kyrgyzaltyn JSC(Kyrgyzaltyn), a Kyrgyz
joint stock company whose shares are 100% owned by the Government of the Kyrgyz Republic.
Project construction began in late 1994 and was financed by Cameco and an international
group of banks and lending agencies. The mine achieved commercial production in the second
quarter of 1997, after incurring capital expenditures of US $452 million. Kumtor Operating
Company (KOC), then a wholly owned subsidiary of Cameco, was granted responsibility to
operate and manage the project for a ten-year period to May 2007 for which KOC received a
management fee. This period has since been extended to the life of the concession pursuant
to the Kumtor restructuring described below.
In December 2003 Cameco, Cameco Gold Inc. (Cameco Gold), Kyrgyzaltyn and Centerra Gold Inc.
(Centerra) entered into the Kumtor Restructuring Agreement, under which Kyrgyzaltyn, Cameco
Gold and its affiliate, Kumtor Mountain Corporation (KMC), agreed to sell to Centerra all of
their respective shares in KGC. This restructuring was completed in June 2004. On June 30,
2004 Centerra completed its initial public offering (IPO) and commenced trading on the
Toronto Stock Exchange. As a result of the restructuring Cameco Gold and KMC hold a
Strathcona Mineral Services Limited
majority shareholding interest in Centerra of 52.7%, while Kyrgyzaltyn holds 15.7%
of the Centerra shares.
1.3 Property Location and Description
The Kumtor mine is located in the southeastern part of the Kyrgyz Republic, one of the
independent successor states of the former Soviet Union, some 350 kilometres to the
southeast of the Kyrgyz capital of Bishkek and about 60 kilometres to the north of the
international boundary with the Peoples Republic of China, in the Tien Shan Mountains, at
41º 52 N and 78º 11 E. The mill site is situated in alpine terrain at an elevation above
4000 metres, with the pit wall extending above 4400 metres. The climate is dry and
continental with a mean annual temperature of minus 8°C. Local valleys are filled with
active glaciers, and the mine area is in permafrost that extends down to elevation 3900
metres.
Mining takes place on the Concession Area, a 750-hectare parcel of land centred on the
Kumtor gold deposit to which KGC has been granted the exclusive rights to all minerals. As a
result of the recent expansion of the mineral resources and reserves, KGC has applied for
two additional mining concession areas situated to the northeast and to the southwest of the
Concession Area, respectively. To facilitate the initiation of mining at the Southwest
deposit, located outside of the Concession Area, KGC has recently been granted a temporary
concession covering the Southwest deposit (the Southwest Mining Licence), renewable after
its expiry date of July 22, 2006.
The Concession Area is surrounded by the Exploration Licence of 26 400 hectares, also
centred on the Kumtor gold deposit, in which KGC was granted the exclusive right to develop
any mineral resources. This includes the right to be granted any additional mining
concessions within the Exploration Licence on the same terms and conditions as those
specified for the Concession Area. The Exploration Licence cannot be renewed beyond its
current expiry date of December 18, 2009, but a new licence may be applied for. Partial or
complete conversion into a mining lease is possible at any time during the currency of the
licence.
1.4 Kumtor Geology and Mineralization
The Kumtor and satellite gold deposits occur in the southern Tien Shan Metallogenic Belt, a
Hercynian fault and thrust belt in Central Asia that extends from Uzbekistan in the west
through Tajikistan and the Kyrgyz Republic into northwestern China.
The mine geology in the Kumtor area is dominated by several major thrust slices with
each thrust sheet containing older rocks than the sheet it structurally overlies. The
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slice hosting the gold mineralization is composed of Vendian (youngest Proterozoic or oldest
Paleozoic) meta-sediments that are strongly folded and schistose. In most areas, the Kumtor
Fault Zone (KFZ), a dark-grey to black, graphitic gouge zone, forms the footwall of this
structural segment. The KFZ strikes northeasterly, dips to the southeast at moderate angles
and has a width of up to 30 metres. The adjacent rocks in its hanging wall are strongly
affected by shearing and faulting for a distance of up to several hundred metres. The rocks
in the structural footwall of the KFZ are Cambro-Ordovician limestone and phyllite, thrust
over Tertiary sediments of possible continental derivation that in turn rest, with apparent
profound unconformity, on Carboniferous clastic sediments.
Gold mineralization occurs where the Vendian sediments have been hydrothermally altered and
mineralized, an event that may have taken place in late Paleozoic time. Gold mineralization
has been observed over a strike distance of more than twelve kilometres, with the Kumtor
deposit being the most important accumulation. Other known occurrences along the mineralized
trend that have either mineral reserves or mineral resources are the Southwest Deposit and
the Sarytor Zone, and additional mineralization is known from the Northeast, Akbel and
Bordoo areas.
Mineralization took place in four main pulses with the mineralization being most intense,
and the gold grade being the highest, where the metasomatic activity was continuous through
phases two and three. Substantial volumes affected by such activity are represented by the
Stockwork Zone, the economic mainstay of the operation to date, and by the SB Zone, whose
recent discovery has resulted in the increase in the mineral reserves at Kumtor as
summarized in this report.
Native gold and gold-bearing minerals occur as very fine inclusions in pyrite, with an
average size of only 10 microns, which accounts largely for the partly refractory nature of
the Kumtor ore. However, the fine grain size of the gold also renders assaying of this
mineralization relatively reliable, with only a small nugget effect. Post-ore faults often
carry significant quantities of graphite, and other carbonaceous components which constitute
the source for the preg-robbing character of some of the mineralization.
1.5 Mining Operations
Mining and processing operations have had to overcome the challenges of operating in a
remote part of the Kyrgyz Republic and also in a dry cold climate at an altitude above 4000
metres. The Kumtor deposit is mined in a large open pit where total material mined in 2005
was 81 million tonnes, or about 222 000 tonnes per day. Unit mining costs have been very
low, primarily because of favourable topography for
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short haul distances for disposal of waste and delivery of ore to the process plant, but
have increased in the past two years, in line with the general global experience of large
open-pit mines.
Ore treatment has been at the rate of close to 5.5 million tonnes per year or 15 000 tonnes
per day since commencement of operations. The fine-grained nature of the gold mineralization
within sulphides has resulted in a flowsheet whereby a sulphide flotation concentrate is
subjected to fine grinding prior to cyanide leaching of the gold in a conventional
carbon-in-leach circuit with gold recovery in 2005 being 81.2%.
Gold production during the nine-year period 1997-2005 from the milling of 48 million tonnes
of ore grading 4.5 grams of gold per tonne (g/t) has been 172 tonnes or 5.5 million ounces.
Citizens of the Kyrgyz Republic represent 95% of the total workforce of 1653 employees as of
the end of 2005, and this high proportion demonstrates the successful adaptation of the
Kyrgyz citizens to the employment opportunities at Kumtor and to the training programs
instituted by Cameco and continued by Centerra. The benefits of drawing a high proportion of
the workforce from within the Kyrgyz Republic have included very good operating cost
performance, in a unique and challenging location.
1.6 Mineral Reserves and Resources, Year-End 2005
The mineral reserves and resources for the Kumtor gold mine have been estimated
by Centerra as at December 31, 2005, using a gold price of $400 per ounce.
The estimates of mineral reserves and resources have been derived from a resource block
model incorporating sample data from historical diamond drilling and underground exploration
that has been augmented by a substantial amount of diamond drilling in recent years. While
the experience of reconciling eight years of production (1997 to 2004) with the reserve
estimates for the areas mined had resulted in a high degree of confidence in previous
reserve estimates, the progress of mining into parts of the Kumtor deposit with narrower and
less continuous zones of mineralization has prompted the addition of a provision for
external mining dilution into the newest block model that was used for the estimation of the
year-end 2005 mineral resources and reserves.
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Kumtor Mineral Reserves and Resources at December 31, 2005
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Contained Gold |
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Tonnes |
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Gold |
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Ounces |
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Tonnes |
Category |
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(000s) |
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g/t |
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(000s) |
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Mineral Reserves |
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Proven |
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17 600 |
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3.7 |
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2 099 |
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65 |
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Probable |
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22 562 |
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3.9 |
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2 854 |
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89 |
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Total |
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40 162 |
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3.8 |
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4 953 |
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154 |
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Mineral Resources 1 |
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Measured |
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13 406 |
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3.8 |
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1 634 |
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51 |
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Indicated |
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10 601 |
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4.1 |
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1 387 |
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43 |
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Measured & Indicated |
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24 007 |
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3.9 |
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3 021 |
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94 |
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Inferred |
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5 475 |
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4.6 |
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803 |
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25 |
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1 |
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Mineral resources are in addition to mineral reserves. Inferred m ineral resources include both
open pit and underground resources. Mineral resources have not been proven to be economically
viable. |
The mineral reserves of 40 million tonnes with a grade of 3.8 g/t gold have increased
substantially from those of a year earlier, mainly because of the discovery of the high-grade SB
Zone in the southwestern part of the Kumtor deposit. As was the case a year earlier, the reserves
include a modest tonnage from the Southwest deposit.
The reserves are scheduled to be mined and milled over the eight-year period 2006-2013, with
low-grade stockpiles being treated in the last two years. Forecast gold production is 4.1 million
ounces, assuming a mill recovery of 83%. To gain access to the deeper parts of the SB Zone, a high
waste-to-ore (strip) ratio is forecast for the period 2007-2010, averaging 19.4. This requires the
purchase of a substantial amount of additional open-pit equipment, commencing in 2006.
Geotechnical concerns pertaining to ground movement in the Kumtor highwall, the impact of the
Davidov glacier on the expanded pit, and the continuing slow movement of the tailings dam are being
addressed.
1.7 Potential for Mineral Reserve Additions
Mineral reserve additions at Kumtor are possible from several sources. The most immediate
possibility is the expansion of the current pit in response to any new mineralization found from
drilling along the northeast extension of the Kumtor deposit. Together with a gold price higher
than $400 per ounce that was used for the current
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pit design, this may allow a layback of the current highwall, thus expanding the pit to
include additional mineral resources that are currently below the optimized pit design.
Drilling continues along the southern extension of the high-grade SB Zone, with some
additional ore being found inside the current final pit design. The recovery of additional
ore outside of the final pit is challenged by the presence of the Davidov glacier, and may
require underground mining.
If additional mineralization of ore-grade character can be found at the northeastern end of
the Southwest deposit located about three kilometres from the Kumtor pit, the overall strip
ratio of this deposit may be lowered, and a portion of the additional resources identified
down-dip of the design pit may become mineable. Initial wide-spaced drilling in the Sarytor
area has also identified gold mineralization of potential ore grade five kilometres from the
mill, and in-fill drilling may upgrade this mineralization to allow pit optimization and
partial conversion into mineral reserves.
Provided that additional exploration is successful, the areas being considered for possible
reserve additions may provide from one to two years of additional operations beyond the year
2013.
1.8 Projected Economic Performance
The performance of the Kumtor mine in achieving production and cost budgets to date has been
very good, and with mining and processing operations now well established, the mine is
expected to meet the life-of-mine (LOM) plan projections for future gold production of 4.1
million ounces at an average cash operating cost of $260 per ounce for the period 2006-2013.
The estimated unit operating costs for the current LOM plan are well founded in the
operating experience at Kumtor, and are at a level slightly higher than that experienced in
the past two years.
Capital expenditures over the life of the mine are estimated at $132 million, mainly to
enable the mine to deal with the additional waste mining required for the recovery of the
newly-found SB Zone, and to a lesser extent with the remedial action to, and additional
lifts on, the tailings dam. For 2006 and 2007, capital expenditures totalling $119 million
have been approved by Centerra.
Centerra has made a strong commitment to fund a continued exploration effort to extend the
life of the Kumtor operation, and budgets for subsequent years will be established following
an assessment of the exploration results of each year. Exploration expenditures are not
included in the capital budget and will be funded from cash provided by operations and
existing cash. For 2006, a budget of $11.4
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million has been approved, mostly for surface drilling, to identify new mineral resources,
and to upgrade existing mineral resources to a higher category or to provide the foundation
on which they can be converted to mineral reserves.
As of December 31, 2005 KGC had two loans of $10 million each, repayable to Centerra,
remaining from the original senior and subordinated debt financing arranged for the
development of the Kumtor project, and repayment is to be completed by June, 2008. All of
the remaining debt with external lenders involved in the original Kumtor project financing
has either been repaid or converted to equity as part of the initial
public offering of shares by Centerra.
Based on projected gold production for the Kumtor mine and associated operating costs for
the period 2006-2013, estimates for sustaining capital, repayment of the outstanding $20
million inter-company debt, and a gold price of $400 per ounce for the eight-year period,
KGC would have net mine cash flow of $363 million, before allocation of funds for
exploration programs. At a gold price of $500 per ounce, net mine cash flow prior to
exploration expenditures would increase to more than $600 million if that gold price was
maintained over the same period, although a sustained higher gold-price would increase the
reserve base and mine life.
A 10% increase in operating costs over the period 2006-2013 would decrease cumulative net
mine cash flow by almost $100 million if all other parameters including the gold price
remained unchanged. The possibility of a significant decrease in the gold grade from that
currently estimated in the LOM plan is considered unlikely given the good reconciliation to
date between reserve grade and the grades recorded from mining and processing.
As a consequence of our lengthy association with the Kumtor project and the resultant
familiarity with its personnel, and the policies and standards followed in the management
and conduct of mining operations, and the very good production and cost performance during
the nine years the mine has been in operation, we are of the opinion that the Kumtor mine
should be able to achieve the production, cost and economic performance targets for the
current mine plan with the possibility of extending the mine life as a result of the
commitment to further exploration in the Kumtor area.
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2. INTRODUCTION
2.1 Background
A technical report for the Kumtor gold mine has been requested by Centerra Gold Inc.
(Centerra) and Cameco Corporation (Cameco), to update the technical report of May 2004
prepared by Strathcona Mineral Services Limited (Strathcona). As of December 31, 2005,
Cameco held 52.7% of the share capital of Centerra. Kumtor Gold Company (KGC), a
wholly-owned subsidiary of Centerra, holds the Centerra interest in the Kumtor project and
the surrounding exploration area. The Kumtor mine is operated by Kumtor Operating Company
(KOC), which is incorporated in the Kyrgyz Republic and is also a wholly-owned subsidiary of
Centerra. Centerra became a publicly-listed company on the Toronto Stock Exchange in June
2004 as the result of the spin-off of the gold assets including the Kumtor project,
previously held by Cameco Gold Inc., a wholly owned subsidiary of Cameco.
The Kumtor operation is governed by an Investment Agreement entered into as of December 31,
2003, between Centerra, KGC and the Government of the Kyrgyz Republic setting out the terms
and conditions applicable to the Centerra operation and development of the Kumtor project.
The Investment Agreement has an indefinite term and shall not be terminated, except by
agreement of the parties, prior to the expiration of the fifty-year term of the Concession
Agreement, which grants the right to explore and develop the Kumtor deposit. The Concession
Agreement may be extended beyond its 50-year term, or may be terminated earlier upon
exhaustion of the Kumtor deposits and completion of mining.
There are a number of material legal documents, including the Investment
Agreement, that are briefly described as follows:
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The Kumtor Restructuring Agreement, dated December 31,
2003, among Centerra, Cameco, Kyrgyzaltyn and Cameco Gold. |
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The Investment Agreement, dated December 31, 2003, among
Centerra, the Government of the Kyrgyz Republic and KGC. |
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The Amended and Restated Concession Agreement (Concession Agreement) dated December
31, 2003 among KGC and the Government of the Kyrgyz Republic under which the Government of
the Kyrgyz Republic granted KGC a concession giving KGC the exclusive rights to the
exploration and development of the Kumtor deposits. |
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The Operating Agreement dated September 3, 1993 as subsequently amended among KGC and
KOC, under which KOC is appointed as operator of the Kumtor mine. |
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The Centerra Shareholders Agreement, dated January 9, 2004, among Centerra,
Kyrgyzaltyn, Cameco Gold and KMC. |
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The Agency Exchange Agreements, dated April 30, 2004 among Centerra, KGC and each of
International Finance Corporation (IFC) and European Bank for Reconstruction and
Development (EBRD), respectively, under which IFC and EBRD assigned the benefit of two
$10-million loans to Centerra in exchange for an equity interest in Centerra and certain
cash payments. |
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The Insurance Risk Rights Plan Agreement, dated June 21, 2004, among Centerra
and CIBC Mellon Trust Company. |
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The Priority Power Supply Agreement dated May 22, 1995 among the State Joint Stock
Energy Holding Company of the Kyrgyz Republic and KGC, under which the Kumtor project is
guaranteed an uninterrupted source of electricity. |
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The Gold and Silver Sale Agreement among KOC on behalf of KGC, Kyrgyzaltyn and the
Government of the Kyrgyz Republic under which Kyrgyzaltyn has agreed to purchase all of
the gold produced by the Kumtor project for reprocessing at its refinery in the Kyrgyz
Republic as amended by the Gold Payment Agreement, dated December 22, 2005, between
Kyrgyzaltyn, Centerra Gold, KOC and KGC, which for a limited period of time provides
Kyrgyzaltyn with a deferred payment facility; and |
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The Reclamation Trust Deed establishing the reclamation trust described in
Section 17.10 below. |
2.2 Terms of Reference
Strathcona has been retained by Centerra to provide an independent technical review and report on
the mineral resources and reserves of the Kumtor gold project as at the end of 2005. The report is
to comply with the standards for an independent technical review as set forth in National
Instrument 43-101 pertaining to Standards of Disclosure for Mineral Projects (NI 43-101). The
requirement for an independent report is due to additional mineral reserves that have been
identified in the past two years in the Kumtor deposit itself and in the adjoining Southwest
Deposit as announced by Centerra in a press release dated January 23, 2006. The operating life of
the project has been extended from mid-2009 to mid-2013. Additional indicated
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Strathcona Mineral Services Limited
mineral resources have also been reported by Centerra in the Sarytor Deposit that
may provide a basis for further production.
Strathcona has a long association with the Kumtor project, having initially been engaged as
Independent Mining Engineer to monitor the performance of the project in accordance with the
loan agreements entered into with EBRD, IFC and the Canadian Export Development Corporation
(collectively, the Agency Lenders) from 1995 until 2002, when the Kumtor debt was
restructured. As part of that assignment, Strathcona president Graham Farquharson visited
the project numerous times, and senior geologist Henrik Thalenhorst travelled to the Kumtor
site from November 27 to December 2, 1998. In preparation for the current report, Henrik
Thalenhorst visited the Kumtor project from January 8 to 14, 2006.
Strathcona was also the author of a technical report on the Kumtor mine that was required
for the initial public offering of Centerra in 2004 (Thalenhorst & Farquharson, 2004). The
2004 report contained a comprehensive description of the technical and economical aspects of
the Kumtor operation. Those items for which no or only inconsequential changes have taken
place in the interim, will only be summarized in this report, referring to the more detailed
descriptions in the earlier report.
The metric system of units is used throughout this technical report, deviating only to
report ounces of gold. The currency used is the United States dollar, unless otherwise
indicated.
2.3 Sources of Information
Following the initial discovery of gold at Kumtor in 1978, the deposit was delineated by a
Soviet-Kyrgyz geological expedition. Extensive drilling programs, surface and underground
sampling programs and studies related to the deposit and its exploitation were completed by
various Soviet agencies. The data from those studies were evaluated and verified by the
Kilborn Feasibility Study initiated by Cameco in 1993. The technical reports on the Kumtor
project prepared since 1993 have been written to contemporary North American standards.
Since commencement of Kumtor production in late 1996, additional technical studies have been
carried out by KOC, Cameco, Centerra and consultants retained by them with expertise in the
fields of geology, resource estimation, engineering, mining, metallurgy, and environment as
part of the ongoing mining operations. Such studies have included the preparation of
periodic mineral resource models and annual mineral reserve estimates and the reconciliation
of the reserve estimates to mine production, all of which have been made available to
Strathcona. Other sources of information have included geological and engineering studies,
sampling and assaying
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results, internal notes and memoranda, computer models, and monthly KOC operating reports
from December 1996 through November 2005. A list of references used in the preparation of
this report is provided in Section 20.
The mineral resources of the Kumtor project that are the subject of this report were most
recently estimated in late 2005 and early 2006 by Centerra. Drilling cut-off date was
December 14, 2005. The mineral reserves based on that resource estimate were estimated
as of December 31, 2005 using a mine plan and pit designs developed by the Kumtor mine
engineering department headed by Bolot Isidirov and Alexander Taskaev. David McNee, Kumtor
Mine Manager, coordinated and supervised the project. The resource and reserve estimates
were prepared under the supervision of Robert Chapman, Director of Mergers and Acquisitions
for Centerra by Dan Redmond, Manager of Reserves and Resources for Centerra, in
collaboration with site geological staff .
Considerable experience has been accumulated by Centerra on the Kumtor project, with mineral
resource and reserve estimates being monitored by means of reserve-production
reconciliation, the results of which are reviewed in Section 15.12.2. As the
independent qualified person, Henrik Thalenhorst of Strathcona assumes overall
responsibility for the content and conclusions of this report.
2.4 Reliance on Other Experts
The information with respect to the Kumtor property and its legal status described in
Section 3 was provided by KGC and has not been independently verified.
3. PROPERTY DESCRIPTION AND LOCATION
The Kumtor gold project is located in the Kyrgyz Republic, one of the independent
successor states of the former Soviet Union, some 350 kilometres to the southeast of the
Kyrgyz capital of Bishkek (Figure 1) and about 60 kilometres to the north of the
international boundary with the Peoples Republic of China, in the Tien Shan Mountains, at
41º 52 N and 78º 11 E (Figure 2).
Under the Concession Agreement, KGC has been granted a concession giving it the exclusive rights to
all minerals within an area of approximately 750 hectares of land centred on the Kumtor gold
deposit and with an expiry date of May 10, 2043 (the Concession Area). The present Kumtor pit, the
waste dumps and the processing plant are located within the Concession Area.
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The recent expansion of the mineral resources and reserves has resulted in the Concession
Area being too small. As a consequence, KGC has applied for a two additional mining
concession areas, one covering the Northeast Zone, the other the Southwest, Sarytor and
adjacent areas to the southwest (the Concession Applications). The Investment Agreement
provides that the Government of the Kyrgyz Republic shall grant any necessary additional
mining concessions within the Exploration License (described below) on the same terms and
conditions as those specified for the original Concession Area.
While the application for the additional areas is under consideration by the Kyrgyz
authorities, on January 23, 2006 KGC was granted a temporary concession covering the
Southwest deposit (the Southwest Mining Licence) with an early expiry date of July 22, 2006.
We have been advised by Centerra that, should the Concession Applications not have been
granted by the date that the Southwest Mining Licence expires, an extension to the Southwest
Mining Licence can be requested.
The coordinates of the Concession Area (black corners 1 to 4), the Concession Applications
(black corners 5 to 9) and the Southwest Mining Licence (red corners 1 to 8) are shown in
Figure 3.
The Concession Agreement also confirms the right of KGC to use sufficient additional lands
for the purposes of the construction and occupation of all mining and milling superstructure
and facilities, work camp and other infrastructure facilities necessary to carry out the
Kumtor project.
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Table 1 Coordinates of Kumtor Mining Concessions
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UTM Coordinates1 |
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Kyrgyz Republic National Coordinates |
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North |
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East |
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North |
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East |
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Concession Area (750 hectares)
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Corner 1 |
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4 637 478.2 |
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266 091.8 |
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4 621 033.7 |
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9 355 309.6 |
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Corner 2 |
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4 699 915.7 |
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267 840.9 |
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4 623 539.6 |
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9 356 957.5 |
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Corner 3 |
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4 636 020.5 |
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268 123.4 |
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4 619 660.4 |
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9 357 397.8 |
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Corner 4 |
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4 638 458.4 |
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269 871.0 |
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4 622 166.4 |
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9 359 046.8 |
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Southwest Mining Licence (56 hectares)
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Corner 1 |
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4 636 109.7 |
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266 582.1 |
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4 619 609.4 |
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9 354 023.0 |
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Corner 2 |
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4 636 001.3 |
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266 999.2 |
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4 619 517.7 |
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9 354 445.2 |
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Corner 3 |
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4 636 520.3 |
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267 046.9 |
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4 620 039.0 |
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9 354 471.6 |
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Corner 4 |
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4 636 582.6 |
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267 307.5 |
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4 620 112.0 |
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9 354 730.2 |
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Corner 5 |
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4 636 174.2 |
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267 644.2 |
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4 619 716.9 |
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9 355 083.7 |
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Corner 6 |
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4 635 616.6 |
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267 064.8 |
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4 619 135.5 |
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9 354 526.2 |
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Corner 7 |
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4 635 581.7 |
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266 717.4 |
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4 619 086.6 |
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9 354 179.8 |
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Corner 8 |
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4 635 878.8 |
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26 522.1 |
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4 619 367.0 |
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9 353 972.3 |
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Concession Applications (625 & 3026, total 3651 hectares)
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Corner 5 |
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4 629 608.5 |
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263 522.4 |
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4 613 068.2 |
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9 353 062.8 |
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Corner 6 |
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4 632 475.8 |
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260 655.2 |
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4 615 815.8 |
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9 350 082.2 |
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Corner 7 |
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4 638 353.3 |
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264 872.2 |
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4 621 858.2 |
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9 354 055.7 |
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Corner 8 |
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4 641 947.0 |
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269 298.3 |
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4 625 628.4 |
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9 358 331.1 |
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Corner 9 |
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4 640 489.7 |
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271 328.4 |
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4 624 255.2 |
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9 360 419.4 |
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The Investment Agreement specifies that KGC will be guaranteed such access to the Kumtor site,
including all necessary surface lands, together with access to water, power and other
infrastructure, as is necessary or convenient for the operation of the Kumtor project. The area
currently in use for such purposes is identified as Surface Rights Area on Figure 3 and covers
approximately 7000 hectares. The Surface rights Area includes the western part of Petrov Lake, the
source of water for the Kumtor project, and covers the tailings management facility, the various
roads and the camp and maintenance buildings.
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The Kumtor Concession has an area of 750 hectares, the Southwest Mining Licence has an area
of not quite 56 hectares, with the extension applied for to the north having an area of 625
hectares, and the southern extension measuring 3026 hectares.
Under the Master Agreement, the predecessor agreement to the Investment Agreement, and under
Section 10 of the Law of the Kyrgyz Republic No. 42 of July 2, 1997 On Subsoil, KGC was
granted the exclusive right to develop any mineral resources within a 7.5 kilometre radius
from the perimeter of the Concession Area. The Exploration Licence granted in 1997 initially
covered an area of approximately 26 660 hectares. This right is continued by the Investment Agreement. The Government of the
Kyrgyz Republic has also agreed to grant any necessary additional mining concessions within
the Exploration Licence on the same terms and conditions as those specified for the
Concession Area.
The licence granting the Exploration Licence was first issued on December 18, 1997. It was
initially renewed on December 31, 2002, and again on December 31, 2005. The current expiry
date is December 18, 2009, but the shape of the licence was changed during the last renewal
to coincide with the principal directions of the Kyrgyz national coordinate system, and its
size reduced slightly to approximately 26 400 hectares, and this area includes the
Concession Area, the Southwest Mining Licence, the Surface Rights Area and the Concession Applications. The Exploration
Licence cannot be renewed again, but a new licence may be requested. Conversion into a
mining lease is possible at any time during the currency of the licence.
The Concession Area, the Southwest Mining Licence and the Exploration Licence are registered
with the Government of the Kyrgyz Republic using the Kyrgyz national coordinate system to
denote the boundaries. Legal surveys are not required to establish the boundaries of the
registered areas, and accordingly, no surveys of such boundaries have been undertaken.
For ongoing work, two grid sets with local coordinates are used. The Kumtor Grid is oriented
nearly north-south/east-west, with a 6° clockwise rotation against the UTM grid, as shown in
Figure 3. For geological work including block modelling and resource and reserve estimation,
local grids are used that are aligned with the predominant structural direction in each area
of interest. The Kumtor and Southwest area geological grids are oriented northwest-southeast
(139° with respect to the Kumtor Grid), and at 25° to the Kumtor Grid at Sarytor. Section
lines are at nominal 40-metre intervals. The orientation of the local grids is indicated in
Figure 5.
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The local mine grids can be translated into the Kyrgyz national coordinate system by the
State Agency on Geodesy who have the appropriate conversion key. However, we have been
advised that there is an intermediate step involving the national 1963 grid system to
which access is restricted.
We have been advised by Centerra that all permits and licenses required for the conduct of
mining operations at Kumtor are currently in good standing. The principal permits are
described in Section 17.7 below. There are no royalties, payments or other agreements or
encumbrances related to the Kumtor mine other than the agreements noted in this report and
various forms of local taxation as set forth in Section 17.13 of this report.
4. ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY
Access to the Kumtor mine site (Figure 2) is by main road from Bishkek to Balykchy,
located on the western shore of Lake Issyk-Kul at an elevation of 1600 metres, a distance of
180 kilometres. A secondary road for 150 kilometres along the south shore of the lake leads
to the town of Barskaun. The final 100 kilometres into the Tien Shan Mountains to reach the
Kumtor mine site is on a narrow winding road that climbs to an elevation of 3700 metres
through the Sary-Moynuk Pass before proceeding eastward on a plateau through which the Kumtor River and other
seasonal rivers flow. KOC has done considerable work to improve and maintain this access road
and despite occasional avalanches and movements of gravel and till down steep slopes during
heavy rains, there has not been any lengthy period during which the road has been out of
service.
The Kumtor mill is situated in alpine terrain at an elevation of 4016 metres, while the highest
waste and glacier mining occurs above 4400 metres. The main camp, administration and maintenance
facilities are at about 3600 metres. Local valleys are occupied by active glaciers that extend down
to elevations of 3800 to 3900 metres, and permafrost in the area can reach a depth of 250 metres.
The region is seismically active as a result of the continuing convergence between India and
Eurasia, but the Kumtor area has a relatively sparse history of seismic activity. All facilities at
Kumtor, including the process plant and tailings storage dam, have been designed in accordance with
recommended seismic standards for the area.
The climate is continental with a mean annual temperature of minus 8°C. Extreme recorded temperatures vary from plus 23°C to minus 49°C, with short summers that
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last from June to September. Precipitation is low at around 300 millimetres per annum, with
the majority falling in the summer months, and snow accumulations of 600 millimetres. There
have been no interruptions to Kumtor operations because of climatic conditions.
Reflecting the high elevation and the harsh climate, sparse low vegetation is restricted to
the valley floors and lower mountain slopes, with a total absence of trees or shrubs.
Most employees of KOC are citizens of the Kyrgyz Republic. The remainder are skilled
expatriates, primarily from Canada. Currently, KOC has 1635 local staff plus 229 personnel
from contractors, and 102 expatriate staff. Employees are transported to the mine site from
Bishkek and the Issyk-Kul region using a company-owned commuter bus service. Supplies are
transported by rail to Balykchy at the west end of Lake Issyk-Kul and then trucked 250
kilometres to the mine site. A helicopter pad is available at the mine site for emergency
use.
The mine site is connected to the Kyrgyz Republic national power grid with a 110-kV overhead
power line that was constructed for the project and that runs parallel to the access road.
The mine maintains two standby generator stations in case of power outages. Fresh water for
human and industrial use is taken from Petrov Lake, situated five kilometres northeast of the mill site (Figure 3). The minimum
water inflow into this glacial lake is estimated to be in excess of 1000 cubic metres per
hour or approximately twice the average project demand.
5. HISTORY
5.1 Exploration History
Intermittent exploration in the general Kumtor area dates back to the 1920s. Debris from the
Sarytor deposit was discovered in 1978 by a geophysical expedition from the state Kyrgyz Geology
department sampling float from the frontal moraine of the Sarytor Glacier (Figure 3). The sole
outcrop of the Kumtor deposit itself was found during follow-up prospecting. From 1979 to 1989, a
systematic evaluation of the Kumtor deposit, and to a lesser extent of the Southwest deposit, was
carried out consisting of several phases of surface trenching and geological mapping, diamond
drilling and underground development on three levels culminating in a detailed sampling program of
the central upper part of the Kumtor deposit. A report entitled Results of Detailed Exploration of
the Kumtor Gold Deposit was issued in 1989,
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and an initial reserve statement was issued by the USSR State Committee on
Reserves in March 19902.
After the break-up of the Soviet Union and following the emergence of the Kyrgyz Republic as
an independent country in 1991, Cameco became aware of the Kumtor project, concluded an
agreement with the Kyrgyz Republic in 1992 and retained Kilborn Western Inc. to undertake a
feasibility study of the project (the Kilborn Feasibility Study). The feasibility work
program included data verification (by re-sampling parts of the underground openings and
re-assaying of original sample rejects), additional and definitive metallurgical testwork,
and a re-estimation of mineral resources and reserves using geostatistical methods, a block
model and pit optimization software. The Kilborn Feasibility Study was completed in 1993,
with updates in April 1994 and in May 1995.
Final agreements were signed with, and the Kilborn Feasibility Study was approved by, the
Kyrgyz authorities in 1994, financing arrangements were concluded in 1995 and project
construction was completed late in 1996. After capital expenditures of $452 million,
commercial production was achieved in the second quarter of 1997. Based on a mineral reserve
of 53.5 million tonnes with an average gold grade of 3.9 g/t, the project was forecast to
treat 4.8 million tonnes per year for eleven years, with a total gold production forecast of 5.4 million ounces (169
tonnes).
As the Kumtor deposit was being mined, KOC undertook a substantial amount of additional
diamond drilling on the deposit and on surrounding exploration targets since 1998, to
augment the limited deposit information below elevation 3950 metres, and to identify additional mineral resources and reserves that would extend the life
of the operation. The pertinent statistical data are summarized in Table 23:
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The details of this early work have been described in the Strathcona report (2004). |
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The figures in Table 2 include completed drill holes only, but omit drill holes that had to be
re-drilled. |
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Table
2 Summary of Additional Drilling Completed, 1998 2005
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Kumtor Deposit |
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Exploration Targets |
Year |
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Number of Holes |
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Length (metres) |
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Number of Holes |
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Length (metres) |
|
|
|
|
|
|
|
1998 |
|
|
|
16 |
|
|
|
3 010 |
|
|
|
|
0 |
|
|
|
0 |
|
1999 |
|
|
|
48 |
|
|
|
12 708 |
|
|
|
|
20 |
|
|
|
3 304 |
|
2000 |
|
|
|
0 |
|
|
|
0 |
|
|
|
|
20 |
|
|
|
2 977 |
|
2001 |
|
|
|
43 |
|
|
|
12 735 |
|
|
|
|
30 |
|
|
|
5 352 |
|
2002 |
|
|
|
10 |
|
|
|
2 119 |
|
|
|
|
50 |
|
|
|
8 646 |
|
2003 |
|
|
|
50 |
|
|
|
14 349 |
|
|
|
|
30 |
|
|
|
4 543 |
|
2004 |
|
|
|
65 |
|
|
|
22 263 |
|
|
|
|
66 |
|
|
|
12 684 |
|
2005 |
|
|
|
146 |
|
|
|
44 863 |
|
|
|
|
52 |
|
|
|
7 969 |
|
|
|
|
|
|
|
|
Total |
|
|
|
378 |
|
|
|
112 047 |
|
|
|
|
268 |
|
|
|
45 475 |
|
|
|
|
|
|
|
|
In the Kumtor mine area, the drill holes are now generally spaced 40 metres along strike and
40 to 80 metres down-dip in geologically complex areas, and at 80 metres along strike and 60 to 80
metres down-dip in other areas.
5.2 Mineral Reserves History
The mineral resource and reserve estimates at Kumtor have evolved over time. The principal
estimates from 1990-2005 are summarized in Table 3 which does not include the reserve estimates for
the Southwest Deposit to allow comparison with the original Soviet estimate.
When comparing the results of the individual estimates in Table 3, it should be recognized that the
cut-off grade has changed significantly through the project history, making direct comparisons
difficult. The initial Soviet polygonal estimate in 1990, given its character, over-estimated the
grade and under-estimated the ore tonnage. It also used a cut-off grade that was below a reasonable
economic level in an effort to mine as much of the Kumtor deposit as possible. The Soviet estimate
is not in compliance with past or present reporting guidelines in Canada.
21
Strathcona Mineral Services Limited
Table
3 Kumtor Deposit History of Mineral Reserve Estimates
millions of tonnes ore and waste and millions of ounces of
gold
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Mined before Date of |
|
|
|
|
|
|
Mineral Reserve In Situ - Stockpiles Excluded |
|
|
Reserve Estimate(1) |
|
|
Total Deposit |
|
|
|
Cut-Off |
|
Block |
|
Bottom |
|
Gold |
|
Ore |
|
Waste (2) |
|
|
Ore |
|
Waste (2) |
|
|
Ore |
|
Waste (2) |
|
Total |
|
Contained Gold |
|
|
|
Grade |
|
Model |
|
Bench |
|
Price |
|
Tonnes |
|
Gold |
|
Tonnes |
|
S/R |
|
|
Tonnes |
|
Gold |
|
Tonnes |
|
S/R |
|
|
Tonnes |
|
Gold |
|
Tonnes |
|
S/R |
|
Tonnes |
|
Ounces |
|
Tonnes |
Reserve Estimate |
|
|
g/t |
|
|
|
|
|
|
|
|
|
g/t |
|
|
|
|
|
|
|
|
g/t |
|
|
|
|
|
|
|
|
g/t |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
USSR State Committee, 1990 |
|
|
|
1 |
|
|
Polyg. |
|
|
3 700 |
|
|
|
?? |
|
|
|
66.2 |
|
|
|
4.3 |
|
|
Not estimated
|
|
|
No Production
|
|
|
|
66.2 |
|
|
|
4.3 |
|
|
No Data
|
|
|
9.2 |
|
|
|
285 |
|
Feasibility Study, April 1994 |
|
|
|
2 |
|
|
GSII |
|
|
3 796 |
|
|
$ |
350 |
|
|
|
53.5 |
|
|
|
3.9 |
|
|
|
273.3 |
|
|
|
5.1 |
|
|
|
No Production
|
|
|
|
53.5 |
|
|
|
3.9 |
|
|
|
273.3 |
|
|
|
5.1 |
|
|
|
326.8 |
|
|
|
6.7 |
|
|
|
209 |
|
KOC, October 1, 1995 |
|
|
|
1.7 |
|
|
GSII |
|
|
3 722 |
|
|
$ |
375 |
|
|
|
76.6 |
|
|
|
3.7 |
|
|
|
581.3 |
|
|
|
7.6 |
|
|
|
No Production
|
|
|
|
76.6 |
|
|
|
3.7 |
|
|
|
581.3 |
|
|
|
7.6 |
|
|
|
657.9 |
|
|
|
9.1 |
|
|
|
283 |
|
KOC, December 31, 1998 |
|
|
|
1.7 |
|
|
OK99c |
|
|
3 800 |
|
|
$ |
325 |
|
|
|
31.4 |
|
|
|
4.6 |
|
|
|
197.5 |
|
|
|
6.3 |
|
|
|
|
10.8 |
|
|
|
4.8 |
|
|
|
57.7 |
|
|
|
5.3 |
|
|
|
|
42.2 |
|
|
|
4.7 |
|
|
|
255.2 |
|
|
|
6.0 |
|
|
|
297.4 |
|
|
|
6.3 |
|
|
|
196 |
|
KOC, December 31, 1999 |
|
|
|
1.7 |
|
|
KS-1 |
|
|
3 800 |
|
|
$ |
301 |
|
|
|
32.7 |
|
|
|
4.4 |
|
|
|
247.8 |
|
|
|
7.6 |
|
|
|
|
18.9 |
|
|
|
4.3 |
|
|
|
90.8 |
|
|
|
4.8 |
|
|
|
|
51.6 |
|
|
|
4.4 |
|
|
|
338.6 |
|
|
|
6.6 |
|
|
|
390.2 |
|
|
|
7.2 |
|
|
|
225 |
|
KOC, December 31, 2001 |
|
|
|
1.5 |
|
|
KS-3 |
|
|
3 770 |
|
|
$ |
300 |
|
|
|
29.8 |
|
|
|
3.9 |
|
|
|
329.4 |
|
|
|
11.1 |
|
|
|
|
31.0 |
|
|
|
4.4 |
|
|
|
174.4 |
|
|
|
5.6 |
|
|
|
|
60.8 |
|
|
|
4.2 |
|
|
|
503.8 |
|
|
|
8.3 |
|
|
|
564.6 |
|
|
|
8.1 |
|
|
|
253 |
|
KOC, December 31, 2003 |
|
|
|
1.3 |
|
|
KS-4 |
|
|
3 754 |
|
|
$ |
325 |
|
|
|
26.2 |
|
|
|
3.6 |
|
|
|
352.7 |
|
|
|
13.5 |
|
|
|
|
41.0 |
|
|
|
4.4 |
|
|
|
296.5 |
|
|
|
7.2 |
|
|
|
|
67.2 |
|
|
|
4.1 |
|
|
|
649.2 |
|
|
|
9.7 |
|
|
|
716.4 |
|
|
|
8.8 |
|
|
|
275 |
|
KOC, December 31, 2004 |
|
|
|
1.3 |
|
|
KS-5 |
|
|
3 754 |
|
|
$ |
375 |
|
|
|
26.3 |
|
|
|
3.4 |
|
|
|
382.0 |
|
|
|
14.5 |
|
|
|
|
46.0 |
|
|
|
4.4 |
|
|
|
377.9 |
|
|
|
8.2 |
|
|
|
|
72.3 |
|
|
|
4.0 |
|
|
|
759.9 |
|
|
|
10.5 |
|
|
|
832.3 |
|
|
|
9.4 |
|
|
|
292 |
|
|
|
|
|
|
|
|
|
|
|
KOC, December 31, 2005 |
|
|
|
1.3 |
|
|
KS-6 |
|
|
3 620 |
|
|
$ |
400 |
|
|
|
35.3 |
|
|
|
4.1 |
|
|
|
621.4 |
|
|
|
17.6 |
|
|
|
|
52.2 |
|
|
|
4.2 |
|
|
|
452.8 |
|
|
|
8.7 |
|
|
|
|
87.5 |
|
|
|
4.1 |
|
|
|
1,074.2 |
|
|
|
12.3 |
|
|
|
1,161.7 |
|
|
|
11.7 |
|
|
|
363 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(1) |
|
Includes the low-grade stockpiled ore not yet milled |
|
(2) |
|
Includes sub-grade mineralization, waste, fill and ice |
22
Strathcona Mineral Services Limited
Geostat Systems International Inc. (Geostat) used the Soviet information to develop a block
model (GSII model) for the Kilborn feasibility study. The GSII model remained the official
reserve model until early 1999 and was in compliance with the reporting guidelines of
National Policy 2A in effect at the time. It used the original mineralized envelope as
defined by Soviet geologists, which was too broad. As a result, the grade interpolation of
the GSII block model smeared gold grades away from higher-grade areas into lower-grade
sections of the deposit, and thus over-estimated the tonnage but under-estimated the grade
of the feasibility study mineral resources and reserves.
Since 1999, a number of additional block models have been created by KOC (mostly with the
assistance of Cameco staff), each an improvement over its predecessor, by incorporating the
increasing geological knowledge about the deposit (Table 2) and about the grade distribution
experienced during mining. This process has now culminated in the KS-6 model, which
incorporates all information available as of December 14, 2005. All resource and reserve
estimates by KOC, Cameco and Centerra since 2002 (the KS-3, KS-4 and KS-6 models) are in
accordance with NI 43-101.
The mineral reserve estimates for the Kumtor deposit, before mining, have varied over time,
between 42 million tonnes grading 4.7 g/t gold with a strip ratio of 6.0, and most recently
90 million tonnes grading 4.1 g/t gold with a strip ratio of 11.9 (excluding the Southwest
deposit ) . Similarly, the gold contained in the reserves has varied from a low of
6.3 million ounces (196 tonnes) to a high of 11.6 million ounces (362 tonnes), with the
latter surpassing comfortably the original Soviet estimate of 285 tonnes of contained gold
in 1990. The variance in the reserve estimates over the years is due primarily to
fluctuations in the price of gold, a gradual decrease of the unit operating costs which
allowed for an increased strip ratio, and an improved geological model based on additional
drilling results. The recent discovery of the SB Zone has added a second, high-grade area to
the deposit that was unknown until 2004.
5.3 Production History
The Kumtor mill started processing ore in December of 1996. As of December 2005, a total of
48.1 million tonnes of ore has been milled with an average gold content of 4.5 g/t. Since
start-up, 172.5 tonnes or 5.6 million ounces of gold have been recovered. Stockpiles yet to
be milled contain 0.7 million tonnes of ore with an average gold grade of 2.8 g/t and 1.7
million tonnes of low-grade with an average gold grade of 1.4 g/t. In addition, 449 million
tonnes of waste and 3.7 million tonnes of ice had been mined for an overall strip ratio of
8.7 to 1, with the low-grade stockpiles counted as ore.
23
Strathcona Mineral Services Limited
Annual production data compiled from the monthly operating reports issued by KOC are shown
in Table 4, which uses the Kumtor reporting terminology, as more fully explained in Section
17.2. Ore is material estimated to grade above 1.5 g/t gold currently (above 1.7 g/t in
earlier years), and low-grade is material with a grade between 1.3 g/t and the
ore cut-off grade in effect at the time of reporting. Because the low-grade material is
currently being used as mill feed and will continue to be processed in accordance with the
life-of-mine (LOM) plan, it is included in reserves and treated as ore when calculating the strip ratio in Table 4.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table 4 Kumtor Production History |
thousands of tonnes of ore and waste and thousands of ounces of gold
|
|
|
|
Ore & Low-grade |
|
Waste Mined |
|
|
Ore Milled |
|
Gold Produced |
|
|
|
|
|
|
|
|
|
Strip |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Tonnes |
|
Gold (g/t) |
|
Tonnes |
|
Ratio |
|
|
Tonnes |
|
Gold (g/t) |
|
% Recovery |
|
Ounces |
|
Tonnes |
|
|
|
|
|
|
|
1996 |
|
|
|
477 |
|
|
|
4.1 |
|
|
|
13 346 |
|
|
|
28.0 |
|
|
|
|
18 |
|
|
|
1.8 |
|
|
|
58.2 |
|
|
|
10 |
|
|
|
0.3 |
|
1997 |
|
|
|
5 017 |
|
|
|
5.2 |
|
|
|
17 946 |
|
|
|
3.6 |
|
|
|
|
4 023 |
|
|
|
5.6 |
|
|
|
73.3 |
|
|
|
502 |
|
|
|
15.6 |
|
1998 |
|
|
|
5 349 |
|
|
|
4.5 |
|
|
|
26 425 |
|
|
|
4.9 |
|
|
|
|
5 254 |
|
|
|
4.8 |
|
|
|
78.5 |
|
|
|
645 |
|
|
|
20.1 |
|
1999 |
|
|
|
8 054 |
|
|
|
3.5 |
|
|
|
33 105 |
|
|
|
4.1 |
|
|
|
|
5 298 |
|
|
|
4.5 |
|
|
|
79.4 |
|
|
|
611 |
|
|
|
19.0 |
|
2000 |
|
|
|
6 518 |
|
|
|
4.1 |
|
|
|
36 763 |
|
|
|
5.6 |
|
|
|
|
5 498 |
|
|
|
4.7 |
|
|
|
81.5 |
|
|
|
670 |
|
|
|
20.8 |
|
2001 |
|
|
|
5 606 |
|
|
|
5.2 |
|
|
|
46 863 |
|
|
|
8.4 |
|
|
|
|
5 470 |
|
|
|
5.1 |
|
|
|
83.1 |
|
|
|
753 |
|
|
|
23.4 |
|
2002 |
|
|
|
5 141 |
|
|
|
3.5 |
|
|
|
49 184 |
|
|
|
9.6 |
|
|
|
|
5 611 |
|
|
|
3.7 |
|
|
|
78.1 |
|
|
|
529 |
|
|
|
16.4 |
|
2003 |
|
|
|
4 828 |
|
|
|
5.0 |
|
|
|
72 881 |
|
|
|
15.1 |
|
|
|
|
5 631 |
|
|
|
4.5 |
|
|
|
82.6 |
|
|
|
678 |
|
|
|
21.1 |
|
2004 |
|
|
|
3 428 |
|
|
|
6.2 |
|
|
|
81 427 |
|
|
|
23.8 |
|
|
|
|
5 654 |
|
|
|
4.4 |
|
|
|
82.1 |
|
|
|
657 |
|
|
|
20.5 |
|
2005 |
|
|
|
6 135 |
|
|
|
3.3 |
|
|
|
74 903 |
|
|
|
12.2 |
|
|
|
|
5 649 |
|
|
|
3.4 |
|
|
|
81.2 |
|
|
|
501 |
|
|
|
15.6 |
|
|
|
|
|
|
|
|
Total |
|
|
|
50 553 |
|
|
|
4.4 |
|
|
|
452 842 |
|
|
|
9.0 |
|
|
|
|
48 106 |
|
|
|
4.5 |
|
|
|
80.0 |
|
|
|
5 556 |
|
|
|
172.8 |
|
|
|
|
|
|
|
|
6. GEOLOGICAL SETTING
The Kumtor gold deposit occurs in the southern Tien Shan Metallogenic Belt, a Hercynian
fault and thrust belt that traverses Central Asia, from Uzbekistan in the west through
Tajikistan and the Kyrgyz Republic into northwestern China, a distance of more than 1500
kilometres (Figure 1). Along this belt, described by Cole (1992) as ... a major
metallogenic province which contains many world-class mesothermal-type gold deposits,
.... occur a number of important gold deposits including Muruntau (one of the largest gold deposits in the world), Zarmitan, Jilau and Kumtor. The Tien Shan itself
is an extremely complex fold and fault belt in which various components represent different orogenetic events that span the Phanerozoic and were later overprinted by Alpine-Himalayan
deformation . This belt is located at ...the margin of Paleozoic Asia (Baltica
and Siberia) [to the north] and the Palaeo-Turkestan Ocean (Cole, 1992).
24
Strathcona Mineral Services Limited
The general geology of the Exploration Licence is shown in Figure 4. Figure 5 provides a
composite of the main geologic features and ore accumulations of the Kumtor, Southwest and
Sarytor Areas on the 3800-metre elevation. Figures 6 to 9 illustrate the geology in the
third dimension for the three deposits, providing a good illustration of the structural complexities of the Tien Shan belt.
A comparison of the geological cross sections presented points out the progress that is
being made at Kumtor with respect to the understanding particularly of the structural
features. Assistance is being provided by SRK Consulting from their office in the United
Kingdom in this update of the structural/geological understanding of the deposit. Figure 6
is from that part of the Kumtor deposit where this process has been completed and thus shows
a more complete structural interpretation, while the other sections are interpreted based on
the traditional information on alteration and gold grade.
There are several major thrust slices comprising the mine geology, with an inverted age
relationship. Each thrust sheet contains older rocks than the sheet it structurally
overlies. The slice hosting the gold mineralization is composed of Vendian (youngest
Proterozoic or oldest Paleozoic) meta-sediments, grey carbonaceous quartz-sericite-chlorite
schists or phyllites that are strongly folded and schistose. In most areas, the Kumtor Fault
Zone (KFZ), a dark-grey to black, graphitic gouge zone, forms the footwall of this
structural segment. However, it appears that at Sarytor, the KFZ actually cuts across the
mineralization. The KFZ strikes northeasterly, dips to the southeast at moderate angles and
has a width of up to 30 metres. The adjacent rocks in its hanging wall are strongly affected
by shearing and faulting for a distance of up to several hundred metres. The rocks in the
structural footwall of the KFZ are Cambro-Ordovician limestone and phyllite, thrust over
Tertiary sediments of possible continental derivation that in turn rest, with apparent
profound unconformity, on Carboniferous clastic sediments.
25
Strathcona
Mineral Services Limited
7. DEPOSIT TYPE
Given the location astride a major fault of regional importance and owing to the strong
association of gold mineralization with a multi-phased metasomatic system at relatively high
temperatures, the Kumtor gold deposit, with its satellite deposits, is a member of the class
of structurally controlled meso-thermal gold replacement deposits.
8. MINERALIZATION
Gold mineralization of economic importance occurs where the Vendian sediments have been
hydrothermally altered and mineralized, an event that may have taken place in late Paleozoic
time, based on structural considerations (Ivanov et al, 2000). Gold mineralization has been
observed over a distance of more than 12 kilometres, with the Kumtor deposit itself located
in what is called the Centre Block with a length of 1900 metres, a vertical range of 1000
metres and a width of up to 300 metres. A buried intrusive body is inferred by geophysical
methods to occur some five kilometres to the northwest of the deposit and may be the source
of the mineralization process at Kumtor (KOC, 2002). Other known occurrences along the
mineralized trend that have either mineral reserves or mineral resources are the Southwest
Area and the Sarytor Zone, as shown on Figures 4 and 5.
8.1 General Description
According to Ivanov et al., 2000, mineralization took place in four main pulses. An initial pulse
resulted primarily in pervasive quartz-carbonate-albite-chlorite-sericite-pyrite alteration, with
little gold of economic consequence being deposited. However, this early alteration may have
stiffened the host rocks sufficiently to make them susceptible to the intensive veining,
stockwork and hydrothermal breccia development during the next two pulses that deposited all of the
economically significant gold at Kumtor.
The temperature of formation of the second stage veins was
310±15°C, according to Ivanov & Ansdell,
2002. The mineralogy during the main phases includes early K-feldspar followed by later albite, and
variable amounts of carbonate (calcite, dolomite, ankerite and siderite), quartz, pyrite, sericite,
and chlorite, in addition to small amounts of chalcopyrite, haematite, barite, strontianite and
accessory magnetite, scheelite, ferberite, rutile, cassiterite, sphalerite, galena, native gold, a
number of silver-gold, lead and nickel tellurides and tetrahedrite. The feldspars combined make up
nearly
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Strathcona Mineral Services Limited
20% of the ore, the carbonates collectively 25 to 30%, pyrite 15 to 20%, quartz 5
to 10%, and the remainder are host rock inclusions.
The mineralization is most intense, and the gold grade is the highest, where metasomatic
activity was continuous through mineralization phases two and three. This is particularly
the case for the Stockwork Zone, to a lesser extent for the South Zone, and explains their
higher-than-average gold grades. The last pulse created planar carbonate-pyrite metasomatic
rocks that are associated with zones of intense deformation of previously altered phyllites
and hydrothermal rocks.
Native gold and the gold-silver tellurides are intimately associated with pyrite to the
extent that gold grade and pyrite content are positively correlated (Ivanov et al., 2000).
The gold and the gold-bearing minerals occur as very fine inclusions in the pyrite, with an
average size of only 10 microns. This, together with the poor cyanide leach response of the
gold tellurides, accounts for the partly refractory nature of the Kumtor ore. The refractory
characteristics are reflected in the relatively low historic and forecast gold recovery of
around 80%, despite the very fine grind applied to the pyrite flotation concentrate from
which most of the gold at Kumtor is recovered. However, the fine grain size of the gold also
renders assaying of this mineralization relatively reliable, with only a small nugget
effect.
Most of the mineralization takes the form of veins, veinlets, and breccia bodies in which
the mineralization forms the matrix. In the more intensely mineralized areas, the
surrounding host rock has also been altered. Post-ore faulting is generally parallel to, or
at low angles with, the mineralized sequence. These faults often carry significant
quantities of graphite, and other carbonaceous components which constitute the sources for
the preg-robbing character of some of the mineralization. The graphitic material has been
stockpiled separately and resulted in changes in the milling procedures early in the mine
life.
8.2 The Kumtor Deposit
Within the Centre Block, a number of zones of gold mineralization have been
delineated as shown in Figure 5.
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|
Two parallel zones of alteration and gold mineralization strike northeasterly and dip to the
southeast at 45° to 60°, separated by 30 to 50 metres of barren or poorly mineralized rock.
The South Zone, with a length of 700 to 1000 metres and a horizontal width of 40 to 80 metres,
is reasonably well mineralized throughout its entire length, with an average gold grade of 3
to 4 g/t. The North Zone, somewhat more extensive along strike but with a similar width, has
lesser gold grade |
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Strathcona Mineral Services Limited
continuity and splits into a number of individual lenses that have average gold
grades in the range of 2 to 3.5 g/t.
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|
At their northeastern end, the North and South Zones coalesce into the Stockwork Zone, which
is the heart of the deposit, having the highest gold grades and the best grade continuity. Its
dimensions in the upper part of the deposit are 400 to 500 metres long by 50 to 200 metres
wide, with an average gold grade of 5 to 6 g/t, depending on the cut-off grade. The Stockwork
Zone plunges northeasterly at 40° to 50°, and diminishes in size below elevation 3900. Its
down-plunge continuation below elevation 3900 is known as the NB Zone. Geographically, the
Stockwork Zone is located closest to the pit highwall (Figure 5) and thus governs to a large
extent the overall strip ratio of the pit design. |
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In the southwestern part of the deposit, the SB Zone (structurally a part of the South Zone)
has recently been found below elevation 3900. It widens significantly below the 3800-metre
elevation, and Figure 5 therefore does not show its full significance which is, however,
apparent in cross section 18 (Figure 7). Ongoing drilling in this areas indicates this
mineralization to be similar in character to the Stockwork Zone. While its full dimension
remain to be defined, it appears somewhat smaller than the Stockwork Zone, but is of excellent
grade. It is the SB Zone that has given rise to the large increase in the mineral reserves of
the Kumtor deposit as the result of drilling conducted in 2004 and 2005 in this area. |
8.3 The Southwest Deposit
The Southwest deposit is located three kilometres to the southwest of the Kumtor deposit across the
Davidov glacier, along the Kumtor fault (Figures 4 and 5). Very little drilling has been completed
below the glacier, and continuity of mineralization between the two deposits is unknown. To the
southwest, the Southwest Zone is covered by the Sarytor glacier, beyond which additional
mineralization is known as the Sarytor deposit.
The structural/lithological framework of the Southwest and Sarytor areas is identical
to those of the Kumtor deposit, as described in Section 6 and as shown in Figure 8,
with the structural dips generally somewhat shallower than at Kumtor at an angle of 20° to 50°.
A number of individual zones of mineralization have been identified within an overall mineralized
envelope that is around 100 metres thick and has been traced by surface drilling for a strike
length in excess of one kilometre. Individual zones tend to be relatively narrow and of different
levels of intensity, and their contacts are often marked by tectonic crush zones with black fault
gouge. The footwall contacts are
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Strathcona Mineral Services Limited
generally sharp and clearly defined, while the hanging wall contacts are more gradational.
Gold enrichment along both contacts can be observed on many sections. Due to flat
orientation of the mineralized zones, their contacts have a sinuous feature in both plan and
section.
8.4 The Sarytor Deposit
The Sarytor area is located further southwest from the Southwest Area. The two zones are
probably contiguous under the Sarytor glacier. The main geological structures are common for
the Southwest and Sarytor areas.
The drill results indicate that the mineralized horizon in the Sarytor area strikes
east-west and dips south at 20° to 30°. The thickness of the mineralized envelope is
relatively consistent and varies from 80 to 120 metres, with the strike length of the known
mineralization being approximately 800 metres.
Host rocks are tectonized slates and phyllites with lenses of till-like conglomerates and
dolomitic slates. Development of background alteration is weak and represented mainly by
vein-type silicification. Host rocks do not carry any elevated gold values. The zone has
been traced by drilling for 200 to 300 metres down dip.
The mineralized envelope hosts three mineralized zones separated by zones of strongly
faulted host rocks. Alteration intensity and zone thickness increase southward. Metasomatism
is represented by banded albite-carbonate-quartz alteration with 3% to 5% pyrite. Barite and
siderite are well developed in the southern part of Sarytor. As a rule, pyrite content is
positively correlated with the gold grade.
9.
DRILLING
Since 1998, KOC have operated their own fleet of diamond drill rigs which currently
number eight. In addition, there are currently two rigs operated by a Kyrgyz contractor. KOC
drill crews are both national (Kyrgyz) and expatriate, under the supervision of a Canadian
drill foreman. International drill contractors are added when drilling requirements are high.
All of the KOC diamond drill holes are inclined and recover HQ-size core. For all of the holes,
drill collars are surveyed and down-hole deviations are measured using either a Sperry-Sun single
shot camera or a Reflex single shot camera. Limitation on set-ups dictate that a certain number of
off-section holes are drilled, particularly within the
Kumtor pit. Drill cores are logged for geological and geotechnical information, and are
photographed prior to sampling. Drill collar coordinates, down-hole deviation
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Strathcona Mineral Services Limited
surveys, assay results, and information on lithology, alteration and mineralization were
recorded in the mine or exploration drilling databases. The drilling database is used for
mineral resource and reserve estimation as described in Section 15.
Drill core recovery typically varies from 80% to 100%, averaging greater than 95%. In
certain cases where the core recovery from mineralized intervals is low, the hole is stopped
and re-drilled to achieve better core recovery. The angle of intersections between the drill
holes and the mineralization is generally such that the length of mineralized drill hole
intervals is equivalent to 80% to 100% of the true width of the mineralization.
10. SAMPLING METHOD AND APPROACH
10.1 Historical Methods
The sampling protocol employed in the years prior to 1993 is described in the Feasibility
Study. As was the case in many projects of the Soviet era, the entire core was removed for
sampling, in intervals of an average down-hole length of 1.4 metres. Core recovery was not
particularly good, averaging only 75%. Trench samples were generally one metre long,
presumably taken horizontally, but the sampling method is not described. Channel samples were
collected from the extensive underground openings approximately one metre above the floor and
varied from 0.5 to 2 metres long, with the channels reported to have measured 10 centimetres
wide by 5 centimetres deep.
10.2 KOC Methodology
For the drilling completed by KOC since 1998, the drill core was measured and checked against
the blocks inserted by the drillers in the core boxes indicating the depth of the hole. The
core is logged and photographed prior to sampling. Sample intervals are chosen based on
geological features such as veining, alteration and mineralization. Individual sample
intervals are normally less than 1.0 metre, however, in unaltered rocks the interval may be
increased to 2.0 metres. The sample intervals are chosen to be representative of the style
and intensity of mineralization. Results to date do not indicate any problems with sampling
bias.
Competent drill core selected for sampling is cut by a diamond saw into two halves. One half
is placed into a numbered bag and sent to the laboratory for assaying. The
other half is placed back in the core box and retained in permanent storage. Core intervals
that are too incompetent to be sawed are sampled with a scoop that fits
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Strathcona Mineral Services Limited
snugly into the individual rows, removing one-half of the material at the discretion of
the sampling technician.
Blasthole cuttings are sampled with a device that is placed radially away from the collar of
the hole. It collects about ten kilograms for an eight-metre bench height. Given the
relatively forgiving nature of the Kumtor mineralization with respect to sampling, this is
satisfactory, if not ideal. Since part of the mining is now below the permafrost line, some
samples are wet, and this should be noted on the sample sheet in addition to the usual
information such as the sample number, since these wet samples tend to be less
representative.
11. SAMPLE PREPARATION, ANALYSES AND SECURITY
11.1 Historical Methods
The sample preparation and analytical protocols used by the Kyrgyz geological personnel in
the years to 1989 were those prescribed by the USSR State Committee on Reserves in Moscow and
are referred to in the Kilborn Feasibility Study.
The analytical work was carried out at the Central Scientific Research Laboratory (CSRL) of
Kyrgyz Geology at Kara Balta. The sample preparation protocol is not described, but the gold
assay method was fire assay for all samples prior to 1989 (a total of 44 580 determinations),
and a more productive atomic absorption method (Feasibility Study, page 3-6) in 1989 (12
612 determinations). Internal and external duplicate assaying was undertaken.
The influence on the gold grade of the relatively poor core recovery of 75% was not
investigated by the Kilborn Feasibility Study. Kilborn concluded in the study that results of
their check assaying on 151 reject samples by a Canadian laboratory were satisfactory the
check assays tended to be slightly higher than the originals. A total of 239 samples
collected by Kilborn in Adit 2 also indicated that the original assay information from
underground sampling was reliable. Supporting evidence for these two cases of assay and
sample checking was not provided in the Kilborn Feasibility Study text.
11.2 KOC Methodology
All sample collection, preparation and assaying from the 1998-2005 drilling programs were
performed by KOC personnel at the KOC-owned site laboratory, which is not certified but is
subjected to periodic calibration and operations checks by the Kyrgyz National Accreditations
agency. Sample collection protocols are monitored by KOCs
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Strathcona Mineral Services Limited
exploration manager and the QA/QC geologist. Preparation and assay protocols are supervised
by KOCs chief assayer at the Kumtor mine. Samples are delivered to and from the laboratory
at the mine site by KOC personnel. Additional security of samples is not required in this
environment.
Since 1998, drill core as well as blast hole, mill and tailings samples have been assayed at
the mine laboratory using the following sample preparation and assaying procedures:
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Samples are received by the sample preparation section with a corresponding manifest
indicating the number of samples and the numerical sample identification. |
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Dry at a temperature of 105° C. |
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Crush the entire sample in three sequential jaw crushers to 95% passing 1.7 millimetres (10
mesh). |
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The last of the three jaw crushers directly feeds a rotary splitter that is set to obtain a
150-gram sub-sample. The remaining reject material is returned to the original bag and, in the
case of core samples, is delivered to the exploration department for storage. |
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Pulverize the sub-sample to 100% passing 106 microns (150 mesh) using a ring-and-puck
pulverizer. |
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A 30-gram aliquot of the pulp is fire assayed with a suitable flux and a gravimetric finish.
The sample weight is decreased to 20 grams for samples with high sulphide content. |
The internal quality control measures at the mine laboratory consist of the routine insertion of
internally prepared standards, certified by four independent laboratories, and a blank at a
combined rate of one standard/blank per 30 samples. The standards constitute Kumtor mineralization
(a head sample of 7.3 g/t gold, a concentrate tail sample of 4.7 g/t gold, a pyrite concentrate
sample of 33.8 g/t gold and a final tailings sample of 0.39 g/t gold). A review of data available
from January 2000 to late 2004 of three of the standards
has shown that for the first two standards, the actual results at the Kumtor laboratory are high by
7% and 9%, respectively, while the third is very close to the accepted value.
In addition, the laboratory also routinely re-assays duplicate pulps at a rate of 20% as an
internal check on assay precision. The results of these measures are monitored by the chief
assayer, the KOC exploration manager and the QA/QC geologist. KOC geological staff do not routinely
submit external blanks and standards as blind
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Strathcona Mineral Services Limited
samples with their drill core sample batches. However, bench composites are created from
drill hole intersections for check assaying and metallurgical test work, and this data
provides a check for the initial assay results.
Quality control checks on reject pulp duplicates are routinely performed by the CSRL at Kara
Balta near Bishkek which is certified by the United Kingdom Accreditation Service under ISO
17025:2005. A minimum of 20% of the total samples from the KOC drill programs have been
re-assayed using the fire assay method with a gravimetric finish. A review of the results
indicates excellent overall coincidence of the two laboratories. As a further check, a total
of 493 re-split sample rejects and 44 pulps were assayed in 2002 both at the mine laboratory
and by the local laboratory of Alex Stewart Assayers and Environmental Laboratory (AESEL)
also located in Kara Balta, which is also certified. Similarly, a small batch of 38 pulp
repeats was check assayed at AESEL in 2005.
During 1998 and 1999, KOC geological staff periodically re-assayed second splits of the
coarse rejects for entire mineralized intervals to compare against the initial assays. Since
1999, this has become standard practice for all mineralized intervals that are intersected
by drilling. The re-split samples retain the original sample number and are re-assayed at
both the mine and the CSRL.
The results of all of the coarse reject check assay program, which is the most pertinent for
the Kumtor resource estimate, are compiled in Table 5 for assay pairs averaging more than
0.1 g/t gold.
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Strathcona Mineral Services Limited
Table 5 Coarse Reject Check Assay Results (>0.1 g/t Gold)
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Pairs |
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Original KOC |
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KOC Re-split |
|
Check Results |
Period |
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Number |
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Removed |
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|
(g/t) |
|
(g/t) |
|
(g/t) |
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Coarse Reject Check Assays at Central Scientific Research Laboratory
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2003 and earlier |
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1 279 |
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8 |
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2.56 |
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2.55 |
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2.56 |
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2004 Kumtor |
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1 893 |
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29 |
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3.02 |
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3.05 |
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3.01 |
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2004 Southwest |
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1 531 |
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13 |
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2.45 |
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2.46 |
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2.35 |
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2005 Kumtor |
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4 916 |
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87 |
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4.50 |
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4.51 |
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4.38 |
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2005 Southwest |
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74 |
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2 |
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1.99 |
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2.07 |
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2.25 |
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Total |
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9 693 |
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139 |
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3.61 |
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3.62 |
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3.54 |
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Pulp Check Assays at Alex Stewart Assayers and Environmental Laboratory |
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Pairs |
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Original KOC |
|
Check Results |
Period |
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Number |
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Removed |
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|
Type |
|
(g/t) |
|
(g/t) |
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2002 |
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489 |
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4 |
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Reject |
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2.34 |
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2.42 |
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2002 |
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44 |
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0 |
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Pulp |
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2.87 |
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2.66 |
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2005 |
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38 |
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0 |
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Pulp |
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1.37 |
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1.35 |
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Total |
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571 |
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4 |
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2.41 |
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2.46 |
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The pairs removed constitute a small proportion of the overall check assay population. They
were excluded from the comparison in Table 5 because the pairs are so dissimilar as to most likely
be caused by something other than an assay accuracy problem or the natural variability (sample
error) of the material being assayed.
Detailed analysis of the KOC/CSRL assay comparison shows that the detection limits of the two
laboratories are different, with CSRL reporting higher values than KOC for values <0.1 g/t. In
the range from 0.1 to 1.0 g/t, KOC is systematically higher, typically by a factor of 10% to 15%.
Above 1 g/t, the two laboratories produce identical average results.
11.3 Conclusion on Sampling and Analytical Protocols
There were some unresolved issues with the original assay database created prior to Camecos
involvement in the Kumtor project. However, much of the deposit covered by the early sampling
programs has now been mined, and the only effect of any deficiency is the possible influence of a
faulty early database during the testing
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Strathcona Mineral Services Limited
of a block model against the mined-out, upper parts of the deposit where this data
predominates.
The sample preparation, assaying and quality control methods used by KOC are industry
standard, and the results of the check assay program indicate that the influence of the high
KOC bias in the range 0.1 to 1 g/t range has a negligible effect on the average grade of a
typical mineralized intersection, as documented in the upper part of Table 5. There will be
no material discrepancy between the current reserve model and future production due to
sampling and analytical protocols.
12. DATA VERIFICATION
During the Kilborn Feasibility Study, the information from surface trenches, underground
crosscuts and drill holes was entered into a computerized database. These data were validated
using industry standard procedures by Geostat. This database was used by Geostat to construct
the GSII model, which was the basis for the resource and reserve estimations in the
Feasibility Study, and its 1994 and 1995 revisions.
Face sample assays from the main drifts and samples from the raises were not included in the
database. The face samples were generally taken in drifts developed along the strike of the ore
zones and were thus not suitable for the quantitative aspects of grade estimation. The few short
raises provided minimal data compared to the considerable amount of data from trenches, crosscuts
and drill holes.
In 1996, the database created by Geostat was verified by Camecos mining resources and methods
department. The database was again compared to the original data contained in the 1989 Kyrgyz
Geology report and, where necessary, corrected or completed. Standard database checks are being
performed regularly under the supervision of Dwayne Melrose, Exploration Manager, who is
responsible for its upkeep and reliability. The database is continuously being verified in the
Gemcom Database Verification Module. Assay results, lithology, drill hole locations and downhole
surveys are verified back to the Laboratory Data Sheets and original data by the Kumtor QA/QC
geologist for every drill hole.
Drill holes in two areas were found to be problematic. Firstly, a series of flat holes oriented to
the northwest from the main Adit 2 drift contained intercepts that were not confirmed by the
neighbouring crosscuts. All of these holes originated in high-grade mineralization and
contamination of the samples was suspected. The assays from these holes were excluded from the
database.
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Strathcona Mineral Services Limited
A second series of drill holes testing below Adit 1 (elevation 3950 metres) of the
underground workings on section lines 61 to 64 contained thick mineralized intercepts that
were inconsistent with other drill holes in the vicinity. The higher-grade mineralization
reported in these holes influenced the Kyrgyz Geology report interpretation as well as the
GSII model resource estimation and the pit designs. This deep mineralization was referred to
as the 3900 Zone. A comprehensive drilling campaign completed during 1998 failed to
confirm the 3900 Zone mineralization. Similarly, several drill holes completed in 1999
failed to confirm other questionable intercepts. The inconsistent intercepts are
attributed to sample contamination due to the drilling equipment and techniques available
before 1988. Based on the confirmation drilling results, the database was modified prior to
the establishment of the KS-1 resource block model to exclude all questionable drill holes. A
small remnant of the original 3900 zone resources, included in the 2004 year-end estimate,
was completely removed from the current estimate.
As a result of the lack of sufficiently detailed information below elevation 3950 metres,
about 28% of the Feasibility Study reserves mineable by open pit containing one-quarter of
the total gold to be mined were substantially less well documented by sampling than the
upper part of the deposit. The large in-fill diamond drill program undertaken by KOC in the
years 1998 to 2005 from various pit benches and setups outside of the pit has now increased
the density of the drill pattern in the lower part of the deposit to that available at the
time of the feasibility study for the upper part. Except for the 3900 Zone, the in-fill
drilling generally confirmed the earlier results, and losses in one part of the deposit were
usually balanced by gains in another.
In-situ volumes of both ore and waste are translated into tonnes by applying a bulk density
factor of 2.85 tonnes per cubic metre which is well established based on direct measurements
on small and larger samples, and is borne out by the reconciliation of predicted and milled
tonnes of ore and waste. This density factor has not changed since the Kilborn Feasibility
Study.
With the in-fill drilling program complete, the database for the deposit is now reliable
down to below the 3700-metre elevation which is the bottom of the original Soviet pit
design. After the removal of previous spurious drill results based on recent drilling, the
successful completion of the in-fill drill program and mine production statistics, the data
relied upon for the estimation of the resource model appear valid.
Strathcona has not undertaken any independent sampling or check assaying as part of
verification of the data base. However, the successful nine-year period of operation for the
Kumtor mine, together with the very good reconciliation between the resource
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Strathcona Mineral Services Limited
model estimates and actual production results, has not indicated any requirement for
independent data verification.
13. ADJACENT PROPERTIES
There is only one other mineral exploration company active in the Kumtor area.
Kentor Gold Limited of Australia (Kentor) acquired exploration concessions in 2003 that tie
on to the exploration licence of Kumtor shown in Figure 3. The firm has conducted preliminary
surface exploration including overburden drilling. KOC exploration personnel are in casual
contact with Kentor personnel.
14. MINERAL PROCESSING AND METALLURGICAL TESTING
This item will be discussed in Section 17.3.
15. MINERAL RESOURCE AND MINERAL RESERVE ESTIMATES
15.1 General
The KS-5 mineral resource model previously in use at the Kumtor mine, a successor model to
the KS-4 model reported upon in the 2004 Strathcona report, was developed in late 2004 by the
Centerra mining resource group in Toronto and technical staff of KOC. In preparing mineral
resource and reserve estimates for the Kumtor project, Centerra used a block model approach
and followed procedures in accordance with Canadian reporting standards as required by NI
43-101. The KS-5 model was used to estimate the mineral resources and reserves of the Kumtor
project as reported by Centerra for the year-end 2004. For the current year-end 2005 estimate
of mineral resources and reserves, the KS-6 model was developed as described in this section.
15.2 Geological Modelling
Grade boundaries at Kumtor tend to be gradational over several metres, and the main
geological challenge in creating a viable geological model for resource estimation has been
the delineation of mineralized zones. For the Kilborn Feasibility Study in 1993, the GSII
model, an all-encompassing mineralized envelope around the main mineralized zones, was
used. This proved too vague and did not provide sufficient constraint during grade
interpolation. As a result, mineral reserve predictions that
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Strathcona Mineral Services Limited
used
the GSII model tended to be correct for the contained gold, but were high for the ore
tonnage and low for its gold grade.
For the KS-4 and KS-5 models, vein and alteration intensities together with gold grade
information were used to subdivide the gold mineralization at Kumtor into twenty-eight
mineralized zones. The delineation of each mineralized zone was completed on eight-metre
spaced bench plans and on 40-metre spaced sections,
took into account the detailed observations (geological mapping and blasthole data) on each
bench mined, and benefited from the substantial additional drilling conducted in 1998 to
2004. Wire frames were created for each zone in GEMCOM, and their volumes determined. A
limitation of the KS-4 and KS-5 models was the use of full blocks for the volume estimate
which made them less accurate in small and narrow mineralized zones.
15.3 Block Models
Block models of slightly different character were used to estimate mineral resources of the
Kumtor, Southwest and Sarytor deposits.
15.3.1 The Kumtor KS-6 Model
The KS-6 model was developed in 2005 for the Kumtor deposit and represents the
interpretation of the geology, tonnage and grade of the deposit before any mining commenced.
It is based upon the most recent drilling information, including the results of all of the
in-fill drilling completed from 1998 to the December 14, 2005 (Table 2), and the new
geologic modelling using the mineralized zones described above. The KS-6 model is based on
blocks measuring 10 by 10 by 8 metres, with the vertical dimension matching the mining bench
height. Each block is assigned to a particular mineralized zone, and a gold grade is
interpolated into the block from the surrounding assay data after assay compositing
(two-metre down-hole gold composites). Prior to grade interpolation the composites are
capped at 60 g/t gold based on cumulative frequency plots and production history, with
capping affecting fewer than 1% of the composites. This reflects the intimate association of
most of the gold with sulphides at Kumtor, which results in relatively few outlier values. A
new feature of the KS-6 model compared to its predecessor models is the inclusion of more
than one rock type in each block (partial or percentage block model), which results in an
improved block tonnage resolution compared to the wireframe volumes and allows the
manipulation of the blocks to include an external dilution provision for each block as
described in Section 15.6
All available assay results for a particular sample are averaged, and the average value is
used for mineral resource estimation. Individual assays are combined into two-metre
composites along drill holes, trenches and underground cross cuts.
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Strathcona Mineral Services Limited
Indicator variography was performed for two groups of data, separately for a South domain
(Stockwork and South Zones), and a North domain (Northeast, North and Flat Zones) at a
cut-off gold grade of 1.66 g/t, the median of the grade data. The results indicate primary
ranges of 10 to 20 metres along strike and down-dip, and of 5 to 15 metres across the dip.
Secondary ranges are 40 to 200 metres along
strike and down-dip, and 60 to 100 metres across the dip.
The KS-6 model uses a general search ellipsoid established for earlier block models (100
metres along strike, 100 metres down-dip, and 5 metres across the dip). The grade
interpolation has also remained unchanged, using ordinary kriging of the capped two-metre
composites. A minimum of two and a maximum of six composites are considered for each grade
determination, all of which may be derived from one drill hole, trench or underground
opening using the search distances determined from the variography. While the grade
information from a different mineralized zone during grade interpolation is admissible,
crossing of mineralized zone boundaries during grade interpolation is relatively uncommon
due to the significant size of most of the zones and the small number of composites used for
the grade interpolation.
For the purpose of estimating resources for possible underground mining, the KS-6 block
model used at a 5 g/t gold cut-off grade within the original wire frames established for the
various mineralized zones.
15.3.2 Southwest and Sarytor Block Models
The Southwest and Sarytor block models have a few minor differences compared to the KS-6
model:
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Capping of high values was at 20 g/t compared to 60 g/t at Kumtor, reflecting the lower-grade
character of these two deposits. |
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The interpolation technique for Sarytor was inverse distance weighting squared compared to
ordinary kriging at Kumtor and Southwest deposits because of the widely spaced drill pattern
at Sarytor. |
15.4 Resource Classification
The mineral resource classification within the KS-6 and Southwest models into measured, indicated
and inferred categories for resources considered for open-pit mining is based on the distance to
the nearest composite. If the nearest composite is within 30 metres, then a block is placed in the
measured category. If the nearest composite is at a distance larger than 30 metres but shorter than
60 metres, then the block is placed in the indicated category. All blocks having the nearest
composite at a distance greater than 60 metres are placed in the inferred category. These
45
Strathcona Mineral Services Limited
parameters
have slightly changed from previous models where the longer distance was set at 50 metres. The
distances used at Sarytor were smaller being 0 to 20 metres for the indicated and from 20 to 40
metres for the inferred class.
Given the generally good grade continuity at low cut-off grades of this large mineral
deposit, and the good reserve-mine-mill reconciliation as detailed in Section 15.12.2, this
classification approach is in accordance with the
requirements of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Resource
and Reserve Definitions as required by NI 43-101, that read in part as follows:
A Measured Mineral Resource is that part of a Mineral Resource for which quantity,
grade or quality, densities, shape, and physical characteristics are so well established
that they can be estimated with confidence sufficient to allow the appropriate
application of technical and economic parameters, to support production planning and
evaluation of the economic viability of the deposit.
An Indicated Mineral Resource is that part of a Mineral Resource for which quantity,
grade or quality, densities, shape, and physical characteristics can be estimated with a
level of confidence sufficient to allow the appropriate application of technical and
economic parameters, to support mine planning and evaluation of the economic viability of
the deposit.
An Inferred Mineral Resource is that part of a Mineral Resource for which quantity and
grade or quality can be estimated on the basis of geological evidence and limited
sampling and reasonably assumed, but not verified, geological and grade continuity.
The proof of continuity for the resources considered for underground mining at the
increased cut-off grade of 5 g/t requires a reduced drill spacing compared to what exists.
Until in-fill drilling can be completed, all of the mineral resources considered for
underground mining have been included in the inferred classification.
The
mineral resources of the Kumtor project exclusive of the mineral reserves are presented in Section 16.1.
15.5 Mineral Reserve Estimation
Mineral reserves are that part of the mineral resource that can be profitably mined given a
specific set of technical and economic parameters. These include the gold price, mine and
mill operating costs, metallurgical recovery, the forecast geotechnical behaviour of the
rocks in the future pit walls, and equipment size parameters. Computer software optimizes
the pit shape by interrogating each block of the block model as to its ability to pay for
its removal plus the incremental tonnage of waste that must be removed to mine the block.
Detailed mine planning using commercial
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Strathcona Mineral Services Limited
software then creates a number of intermittent pit designs that test the ability to access
sufficient ore to provide adequate mill feed while postponing waste mining
as long as possible. This process results in one or more pit shells which recover the
economic part of the mineral resources and which are then engineered in detail by adding
ramps for mining access and by smoothing of the pit walls.
The
CIM Resource and Reserve Definitions required to be adhered to by NI 43-101 read in part
as follows:
A Mineral Reserve is the economically mineable part of a Measured or Indicated
Mineral Resource demonstrated by at least a Preliminary Feasibility Study. This Study
must include adequate information on mining, processing, metallurgical, economic and
other relevant factors that demonstrate, at the time of reporting, that economic
extraction can be justified. A Mineral Reserve includes diluting materials and allowances
for losses that may occur when the material is mined.
A Proven Mineral Reserve is the economically mineable part of a Measured Mineral
Resource demonstrated by at least a Preliminary Feasibility Study. This Study must
include adequate information on mining, processing, metallurgical, economic, and other
relevant factors that demonstrate, at the time of reporting, that economic extraction is
justified.
A Probable Mineral Reserve is the economically mineable part of an Indicated, and in
some circumstances a Measured Mineral Resource demonstrated by at least a Preliminary
Feasibility Study. This Study must include adequate information on mining, processing,
metallurgical, economic, and other relevant factors that demonstrate, at the time of
reporting, that economic extraction can be justified.
The current Kumtor pit design identified as KS-6 LOM0106 was created in early January
2006 and was selected from a total of six different alternatives that spanned choices from
leaving the 2005 pit unchanged to the version finally adopted as offering the best
combination of mine life and cash flow (KOC, 2006). The studies undertaken by KOC and the
LOM plan subsequently adopted by Centerra demonstrate that the Kumtor mineral reserves are
the economically mineable part of a Measured or Indicated Mineral Resource as
required by the CIM Resource and Reserve Definitions.
15.6 Dilution Provisions
The block models created for the Kumtor deposit in the past, up to and including model KS-5,
had no need to provide for external dilution, in the absence of a large grade discrepancy
between model and actual mining experience. The poor reconciliation of the KS-5 block model
with the actual mining experience in the second half of 2005 (Section 15.12.2) prompted a
re-evaluation of this approach. Centerra
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Strathcona Mineral Services Limited
felt that the central part of the Kumtor deposit, with its less continuous and generally
narrower mineralized zones, was not properly estimated by the KS-5 model which die not
provide for external dilution. The major difference between KS-6 and its predecessor models,
apart from the additional drill information available, is the inclusion of an external
dilution provision.
The KS-6 model contains provisions for internal dilution by including low-grade intervals in
the composite grades used for grade interpolation. External dilution was provided for by
adding an arbitrary one-half of the waste tonnage in each block that contains more than one
rock type to its ore tonnage. Since the bulk densities for ore and waste are identical, this
represents simply a shift of the waste/ore ratio inside such a block. Comparison of the two
undiluted and diluted KS-6 models at a cut-off of 1.3 g/t gold is compiled in Table 6.
Table 6 Comparison of KS-6 Model with and without External Dilution
cut-off grade 1.3 g/t gold
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Contained Gold |
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Tonnes (000) |
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Gold Grade (g/t) |
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(000 ounces) |
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In -Pit Undiluted
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Above 1.5 g/t |
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29 402.1 |
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4.6 |
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4 310.4 |
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1.3 to 1.5 g/t |
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3 555.5 |
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1.4 |
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158.9 |
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Total |
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32 957.6 |
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4.2 |
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4 469.3 |
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In -Pit Diluted
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Above 1.5 g/t |
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30 759.8 |
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4.4 |
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4 351.4 |
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1.3 to 1.5 g/t |
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4 546.7 |
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1.4 |
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204.7 |
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Total |
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35 306.5 |
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4.0 |
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4 556.0 |
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Variance
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Above 1.5 g/t |
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5 |
% |
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-4 |
% |
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1 |
% |
1.3 to 1.5 g/t |
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28 |
% |
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1 |
% |
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29 |
% |
Overall |
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7 |
% |
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-5 |
% |
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2 |
% |
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The net effect is an increase in the total tonnage of about 7%, a grade reduction of about 5%,
and a small gain of contained gold. The performance of the diluted KS-6 model against actual
production is discussed in Section 15.12.2. External dilution was provided at the Southwest deposit
in a similar fashion to Kumtor.
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Strathcona Mineral Services Limited
15.7 Economic Pit Design Parameters
The Kumtor mineral reserves available for mining at December 31, 2005 were estimated on the
basis of the KS-6 block model, the current pit design and a gold
price of $400 per ounce. The main economic parameters for this pit design are summarized and
compared to 2005 operating data in Table 7:
Table 7 Kumtor and Southwest Economic Pit Design Parameters
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Southwest |
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2005 Actual |
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Kumtor Pit |
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Pit |
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Gold Price |
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$/ounce |
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445 |
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400 |
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400 |
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Operating Costs |
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Mine |
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per tonne ore mined |
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$ |
0.59 |
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$ |
0.60 |
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$ |
1.29 |
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per tonne waste mined |
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$ |
0.59 |
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$ |
0.60 |
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$ |
0.49 |
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Mil |
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per tonne milled |
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$ |
5.73 |
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$ |
6.50 |
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General
& Administration |
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per tonne milled |
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$ |
6.02 |
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$ |
5.69 |
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Haulage Ramps |
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width |
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45 metres reducing to 25 metres
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grade |
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10%
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Metallurgical Recoveries |
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Head Grade
(g/t) |
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Recovery
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>5 |
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60% to 90% |
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82% to 85% |
3 to 5 |
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60% to 82% |
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75% to 82% |
0 to 3 |
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57% to 69% |
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40% to 75% |
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Metallurgical recoveries are determined from the results of the bench composite assaying and
testwork described in Section 17.2, individually for each mineralized zone. The recoveries
anticipate the full impact of the new ISA mill fine-grinding installation described in Section
17.3, which is projected to improve the gold recovery by four percent. The actual performance in
2005 was 81.2% on a head grade of 3.4 g/t, mostly without the ISA mill. The recovery values are
assigned to each block based on its gold grade and the mineralized zone to which it belongs.
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Strathcona Mineral Services Limited
15.8 Pit Wall Stability and Pit Design Parameters
On July 8, 2002, a highwall failure occurred at the Kumtor mine, resulting in the temporary
suspension of operations. This was a very significant event, which led to the death of one
KOC employee and affected the pit wall over a vertical distance of 280 metres. The slide
caused a considerable shortfall in 2002 gold production because the high-grade Stockwork
Zone was rendered temporarily inaccessible. The waste rock resulting from the movement was
removed by October 2003, and the operation was back to normal shortly thereafter.
Golder Associates Ltd. (Golder), KOCs geotechnical consultant, who have been involved with
geotechnical investigations at Kumtor since the feasibility study stage, assessed the
reasons for the slide and provided guidance with respect to remedial and long-term pit slope
design criteria that would reduce the possibility of a recurrence of such a ground movement.
Concurrent with the initiation of the remedial mining, a program to further investigate the
cause of the failure was undertaken. This program involved detailed surface mapping by KOC
geological staff, the drilling of oriented core holes to attempt to intersect shallow
dipping structures, and the re-evaluation of all geological data from the area of the
failure. In all, 28 holes, with an aggregate length of 6480 metres, were drilled from the
various levels as the highwall was being excavated through the failure debris, and
systematic additional drilling is planned for the next years.
The monitoring system was greatly expanded for the remedial wall as it was being
redeveloped. Survey prisms are spaced at approximately 50 metres horizontally along the
benches and 48 metres vertically. The prisms are monitored by two robotic total stations
located on the southwest and northwest sides of the pit. Two units using time-domain
reflectometry (TDR) and two inclinometers were also installed in the wall, with the TDR
cables and one of the inclinometers. Both the robotic total stations and the TDR data report
to an alarm system in the dispatch office.
The evaluation of the data resulting from the additional investigation programs, combined
with all previous data, both Soviet and KOC, has led to a revision of the geological model
in the area of the northeast wall. The integration of the revised geology into the slope
design process has resulted in the formulation of design criteria for the current ultimate
pit. The criteria suggest that an overall angle of 34° to 36° should be used for the design
of the northeast wall, compared with 42.5° for the pre-failure slope.
In the last two years, reverse (northwest) dipping faults have been recognized in the
eastern part of the deposit that are essentially parallel with the local pit slope, as
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Strathcona Mineral Services Limited
shown in Figure 6. In early 2004, a substantial movement in the southeast wall of the Kumtor open
pit was detected and subsequently explained by the presence of one of these faults. The area
affected by the movement extended over a face length of 300 metres and a wall height of
about 200 metres. This area has now been mined out, but a similar movement occurred in
February 2006 that has been addressed by inserting an extra wide bench. To deal with these
reverse-dipping
faults, a program of geotechnical drilling in this part of the pit is continuing, together
with an ongoing detailed re-interpretation of the fault and fracture patterns of the entire
Kumtor deposit, and the slope angles have also been flattened.
For the final pit design that enclose the December 31, 2005 mineral reserves of the Kumtor
deposit, six design sectors have been used. The slope design parameters for the individual
sectors are summarized in Table 8, and the ultimate pit, the design sectors and the year-end
2005 pit are shown in Figure 10. For that part of the southwestern part of the Kumtor pit
that will be excavated within the existing waste dumps, a slope angle of 31° has been chosen
within the loose materials, which may be slightly conservative.
Table 8 Ultimate Kumtor Pit Design Parameters
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West & |
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South- |
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Northeast & |
Design Parameter |
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South |
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East |
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East |
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Northwest |
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Bench Height (metres) |
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8 |
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8 |
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8 |
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8 |
Berm Spacing (metres) |
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24 |
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24 |
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24 |
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24 |
Berm Face Angle |
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63.5° |
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63.5° |
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63.5° |
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63.5° |
Berm Width (metres) |
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21 to 28 |
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21 |
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16 to 21 |
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21 to 26 |
Inter-Berm Angle |
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31° - 36° |
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36° |
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36° - 40° |
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34° - 36° |
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The overall effect is that nearly all of the slopes are flatter than the natural angle of repose.
Movement in one area of the highwall is continuing. It is located below the original failure in the
upper part of the highwall, but is a slow event that is being held in check by the flattened pit
wall.
The
monitoring of all of the pit walls in the last two years has not indicated any large movements that would result in a substantial risk to the Kumtor reserves.
There are two final pit bottoms at elevations 3620 metres (in the southern part of the pit) and
3778 metres (in the central part) and those two lower pit areas are mined with the highest of the
overall slope angles shown in Table 8 and utilize ramps that narrow to 25 metres.
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Strathcona Mineral Services Limited
Mining of the Southwest deposit is sub-divided into two coalescing pit shells. Following
earlier recommendations by Golder (2002), the pit slope angles were reviewed by KOC (Vdovin,
2005) who adopted a more cautious approach honouring the highly tectonized nature of the
rocks. The design angles for the
Southwest deposit shells are summarized in Table 9.
Table 9 Southwest Pit Design Parameters
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Design Parameter |
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Bench Height (metres) |
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8 |
Berm Spacing (metres) |
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8 to 16 |
Berm Face Angle |
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60° |
Berm Width (metres) |
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9 to 13.5 |
Inter-Berm Angle |
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30° - 40° |
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The overall pit wall angles are in all cases equal to, or less than, 34°. Since there is no
practical experience with pit slopes at the Southwest deposit yet, the walls established early will
have to be carefully monitored.
15.9 Waste Dump Design
Two complete waste dump designs have been completed for the LOM06. The first plan represents
an attempt to minimize waste dumps hauls, and assumes that further displacement of the Davidov
glacier down the valley towards the South West Pit access haul road is acceptable. It assumes that
mining of the SW pit will be complete by the time the displaced glacier over tops the access road.
The second plan minimizes further displacement of the glacier to the southwest, and attempts to
haul waste west into the Lysii valley and to the north east. (KOC 2006, page 13). A final
decision with respect to the waste dump design will be taken in the first part of 2006.
15.10 The Davidov Glacier
The Life of Mine Plan now calls for the excavation of ore from below part of the Davidov glacier in
the southwestern part of the Kumtor deposit (Figure 10) as a result of mining of the newly-found
reserves in the SB Zone. Prior to the identification of the SB Zone, a substantial amount of waste
rock was dumped directly onto the Davidov glacier. This has resulted in the gradual displacement of
the glacier away from the pit, so that the waste, originally lying on glacier ice, now rests on the
original substratum, the basal moraine of the glacier. The new LOM plan will continue this
practice, using waste rock to displace the glacier even further away from the pit and so allow
mining of the deeper parts of the SB Zone.
53
Strathcona Mineral Services Limited
KOC has commissioned two separate investigations into the probable behaviour of the glacier
under these conditions. The two projects were carried out in late 2005 by Golder Associates
(Golder Associates, 2005), who have previously carried out glacier studies at KOC, and by
Kyrgyz rock mechanics specialist B. Chukin (Chukin, 2005). Golder and, to a certain extent
Chukin, agree that it should be
possible to engineer a flow path for the Davidov glacier away from the southern part of
the final Kumtor pit using a waste dump buttress. The two studies also agree that, provided
the glacier movement is parallel to the pit wall, the mass of waste buttress required to
displace the glacier and prevent impact on mining operations is within manageable limits. It
is further recognised that it is critical to maintain an active flow channel for the glacier
to prevent damning and possible overriding of glacier ice over the waste dump buttress and
into the working areas. It is also recognized that, where the movement of glacial ice or
overlying waste dump is towards the working areas, it will be necessary to increase waste
dumping in order to fully displace the ice, ground the waste dump/buttress and hence provide
a diverting effect.
The current design of cut-back 10 (CB-10), the last cutback in the southern part of the
Kumtor pit, reduces the glacier channel to a width of approximately 200 metres for a period
of 12 to 18 months. Following the mining of CB-10, open-pit mining in this area will be
completed, and any subsequent displacement of the waste highwall or glacier towards or into
the pit would not be an issue. CB-10 mining is scheduled for 2009-2010, allowing for a
comprehensive programme to be implemented to assess detailed mining plans, monitor the
glacier and waste buttress movement, and to verify the geotechnical assumptions inherent in
this mine plan.
The main uncertainties of this approach are in respect to three items:
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The relationship between the height of the ice and the height of the waste dump required to
keep the ice at bay is not entirely clear. Monitoring will be required, and if necessary
modification through additional waste dumping. |
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The width of the channel left during CB-10 may not be sufficient to constrain the glacier and
allow its free movement parallel with the pit. |
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The subsequent potential access required for underground mining of those parts of the SB Zone
not recoverable by open-pit mining has not been investigated. |
Because of the remaining uncertainties, all of the ore to be mined during CB-10 (14.9 million
tonnes of ore at an average grade of 3.9 g/t gold) has been placed in the probable reserve
category, including 10.5 million tonnes at an average grade of 3.8 g/t gold that were originally
classified as measured mineral resources.
54
Strathcona Mineral Services Limited
15.11 December 31, 2005 Mineral Reserve Estimate
As the data in Table 3 have shown, the estimate of the total mineable reserve tonnage for
the Kumtor deposit has changed significantly over time in response to variations in the
economic parameters. The current estimate for the Kumtor and Southwest deposits at a gold
price of $400 per ounce is summarized in Table 10. It is important to recognize that this
estimate was produced internally by Centerra, and that no estimation of mineral resources
and reserves independent of Centerra has been completed.
The
stockpile inventories are those reported in the December 2005 mine month-end report,
while the in-pit mineral reserves are those quoted by the mine development plan identified
as KS-6 LOM0106 developed in January 2006, and reflect the mineral reserve status as of
December 31, 2005.
As the Kumtor unit operating costs are well established, any remaining uncertainty with
respect to the KS-6 mineral reserves is a direct consequence of the assessment of the final
highwall pit slope, apart from any significant movements in the gold price.
Figures 11, 12, 13 and 14 show the block model and mineral reserve and resource
information for the four geology sections presented as Figures 6, 7, 8 and 9.
Because of the uncertainties inherent in the final push back phase (CB-10) in the
southwestern part of the deposit adjacent to the Davidov glacier, all of the mineral
reserves falling into this mining phase have been assigned to the probable classification as
discussed in more detail in Section 15.10, including the mineral resources originally
classified as measured.
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4
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As the result of a clerical error, the stockpile reserve statement is lower by 322 000
tonnes and by 24 500 contained ounces compared to the LOM plan, which contains the correct
figures. |
55
Strathcona Mineral Services Limited
Table 10 Kumtor Mineral Reserves at December 31, 2005
thousands of tonnes of ore and waste, thousands of ounces
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Contained Gold |
|
|
|
|
Tonnes |
|
|
Gold |
|
|
|
|
|
|
|
|
|
|
|
|
Ounces |
|
|
Tonnes |
|
Category |
|
|
(000s) |
|
|
(g/t) |
|
|
|
|
|
|
|
|
|
|
|
|
(000s) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
By Category
|
|
|
|
|
|
|
|
|
|
|
Proven |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Stockpiles |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Greater than 1.5 g/t |
|
|
|
363 |
|
|
|
3.2 |
|
|
|
|
|
|
|
|
|
|
|
|
|
38 |
|
|
|
1.2 |
|
Low-grade 1.3-1.5 g/t |
|
|
|
1 739 |
|
|
|
1.4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
77 |
|
|
|
2.4 |
|
Sub-total |
|
|
|
2 102 |
|
|
|
1.7 |
|
|
|
|
|
|
|
|
|
|
|
|
|
114 |
|
|
|
3.6 |
|
Kumtor deposit in-situ |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Greater than 1.5 g/t |
|
|
|
13 615 |
|
|
|
4.3 |
|
|
|
|
|
|
|
|
|
|
|
|
|
1 899 |
|
|
|
59.0 |
|
Low-grade 1.3-1.5 g/t |
|
|
|
1 883 |
|
|
|
1.4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
85 |
|
|
|
2.7 |
|
Sub-total |
|
|
|
15 498 |
|
|
|
4.0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
1 984 |
|
|
|
61.7 |
|
Southwest
deposit in- situ |
|
|
None |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Total Proven |
|
|
|
17 600 |
|
|
|
3.7 |
|
|
|
|
|
|
|
|
|
|
|
|
|
2 098 |
|
|
|
65.3 |
|
|
|
|
|
|
|
|
|
|
|
Probable |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Kumtor deposit in-situ |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Greater than 1.5 g/t |
|
|
|
17 124 |
|
|
|
4.5 |
|
|
|
|
|
|
|
|
|
|
|
|
|
2 452 |
|
|
|
76.3 |
|
Low-grade 1.3-1.5 g/t |
|
|
|
2 670 |
|
|
|
1.4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
118 |
|
|
|
3.7 |
|
Sub-total |
|
|
|
19 794 |
|
|
|
4.0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
2 571 |
|
|
|
80.0 |
|
Southwest deposit in-situ |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Greater than 1.5 g/t |
|
|
|
2 266 |
|
|
|
3.6 |
|
|
|
|
|
|
|
|
|
|
|
|
|
261 |
|
|
|
8.1 |
|
Low-grade 1.3-1.5 g/t |
|
|
|
501 |
|
|
|
1.4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
22 |
|
|
|
0.7 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Sub-total |
|
|
|
2 767 |
|
|
|
3.2 |
|
|
|
Waste
|
|
|
|
283 |
|
|
|
8.8 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Total Probable |
|
|
|
22 561 |
|
|
|
3.9 |
|
|
|
Tonnes |
|
|
S/R |
|
|
|
|
2 853 |
|
|
|
88.7 |
|
|
|
|
|
|
|
|
|
|
|
Total Mineral Reserves |
|
|
|
40 161 |
|
|
|
3.8 |
|
|
|
|
649 573 |
|
|
|
17.1 |
|
|
|
|
4 952 |
|
|
|
154.0 |
|
|
|
|
|
|
|
|
|
|
|
By Deposit
|
|
|
|
|
|
|
|
|
|
|
Kumtor Proven & Probable |
|
|
|
37 394 |
|
|
|
3.9 |
|
|
|
|
621 412 |
|
|
|
17.6 |
|
|
|
|
4 669 |
|
|
|
145.2 |
|
Southwest Proven & Probable |
|
|
|
2 767 |
|
|
|
3.2 |
|
|
|
|
28 161 |
|
|
|
10.2 |
|
|
|
|
283 |
|
|
|
8.8 |
|
Total |
|
|
|
40 161 |
|
|
|
3.8 |
|
|
|
|
649 573 |
|
|
|
17.1 |
|
|
|
|
4 952 |
|
|
|
154.0 |
|
|
|
|
|
|
|
|
|
|
|
Figures may not add due to rounding. The strip ratio (S/R) is calculated on in-situ materials.
56
Strathcona Mineral Services Limited
15.12 Accuracy of Resource and Reserve Estimates
15.12.1 Comparison with Polygonal Approach
In past years, the Kyrgyz State Committee for Resources required that Kyrgyz state
geologists prepare a detailed polygonal manual reserve estimate on geological sections and
plans, using the estimation methods and reporting terminology of the former Soviet Union, in
parallel with the block models being devised by KOC. While this duplication of effort
offered the opportunity to compare the results of the two different approaches, the
independent estimate by the Kyrgyz State Committee is now no longer required.
15.12.2 Reconciliation to Mill Feed
Since the start of operations, KOC staff have kept current reconciliation data that compare
the tonnages and grades predicted by the various block models being used for reserve
estimation at any given time (Table 3) with actual tonnages and grade mined from the pit as
determined by the grade control data, and with the actual mill production data. This was
done at the actual cut-off grades in effect at the time. The reconciliation is somewhat
complicated by the various stockpiles being kept at Kumtor, that effectively decouple the
mine operations from the mill. However, over longer periods, inaccuracies in the stockpile
balances become less severe.
In our 2004 report, we had presented reconciliation data for the earlier block models
for the years 1996 to 2003, and had come to the following conclusions:
|
|
|
The ore control model, based on blasthole data, is a good estimator of the mill feed. For
short-term comparisons, the ore control model can serve as a proxy for the mill. |
|
|
|
|
The overall variance between the earlier block models and the actual mill throughput from
1996 to the end of 2003 was small, although the models collectively tended to over-estimate
the gold grade of the tonnage above the cut-off grade by a small margin. |
|
|
|
|
The KS-4 model was accurate in predicting the milled tonnage and grade for the years 2001 to
2003 at the 1.3 g/t gold cut-off grade. |
|
|
|
|
For smaller tonnages (monthly, quarterly), the random variances between the block model
prediction and actual mining experience were generally quite large, reflecting the relatively
open drill hole pattern at Kumtor. |
61
Strathcona Mineral Services Limited
The challenge to create reliable short-term production forecasts at Kumtor is recognized by
Centerra and will probably become more pronounced in 2006 and 2007 as smaller, less
continuous ore lenses are being mined compared to earlier years.
The relatively poor performance of the KS-5 model in the last quarter of 2005 gave rise to
the creation of the current block model KS-6 that attempts to address the shortcomings of
its predecessor, as is more fully described in Section 15.3.
Table 11 summarizes the reconciliation data for the most recent two block models, KS-5 and
KS-6, the latter being the model used for the current resource and reserve estimates.
The upper section of Table 11 presents the reconciliation for the four quarters of 2005 at a
cut-off grade of 1.5 g/t gold, and the lower section the reconciliation for the years 2001
to 2005 at a cut-off grade of 1.3 g/t gold since there was a considerable amount of
low-grade fed to the mill particularly in 2004, which did not occur in 2005. To make
tonnages strictly comparable, the block model predictions in Table 11 are adjusted for
material delivered to the various stockpiles (because they were not milled), and the mill
figures are similarly adjusted for material received from the stockpiles that were not mined
in the periods for which the comparison is made.
The upper section of Table 11 presents the reconciliation for the four quarters of 2005 at a
cut-off grade of 1.5 g/t gold, and the lower section the reconciliation for the years 2001
to 2005 at a cut-off grade of 1.3 g/t gold since there was a considerable amount of
low-grade fed to the mill particularly in 2004, which did not occur in 2005. To make
tonnages strictly comparable, the block model predictions in Table 11 are adjusted for
material delivered to the various stockpiles (because they were not milled), and the mill
figures are similarly adjusted for material received from the stockpiles that were not mined
in the periods for which the comparison is made.
62
Strathcona Mineral Services Limited
Table 11 Reconciliation of KS-5 and KS-6 Models with Ore Mined and Milled
thousands of tonnes of ore and thousands of ounces
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Period |
|
|
KS-5 Block Model |
|
|
KS-6 Block Model |
|
|
Ore Control Model |
|
|
Mill Feed |
|
|
|
|
|
|
|
Gold |
|
|
|
|
|
|
Gold |
|
|
|
|
|
|
Gold |
|
|
|
|
|
|
Gold |
|
|
|
Tonnes |
|
g/t |
|
Ounces |
|
|
Tonnes |
|
g/t |
|
Ounces |
|
|
Tonnes |
|
g/t |
|
Ounces |
|
|
Tonnes |
|
g/t |
|
Ounces |
|
2005, Q-1 |
|
|
|
1 005 |
|
|
|
4.2 |
|
|
|
137 |
|
|
|
|
943 |
|
|
|
4.3 |
|
|
|
129 |
|
|
|
|
1 053 |
|
|
|
5.2 |
|
|
|
177 |
|
|
|
|
1 435 |
|
|
|
3.7 |
|
|
|
170 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2005, Q-2 |
|
|
|
1 119 |
|
|
|
3.8 |
|
|
|
137 |
|
|
|
|
984 |
|
|
|
3.3 |
|
|
|
104 |
|
|
|
|
1 209 |
|
|
|
4.2 |
|
|
|
165 |
|
|
|
|
1 401 |
|
|
|
3.7 |
|
|
|
167 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2005, Q-3 |
|
|
|
1 709 |
|
|
|
3.3 |
|
|
|
179 |
|
|
|
|
1 629 |
|
|
|
2.8 |
|
|
|
146 |
|
|
|
|
1 658 |
|
|
|
3.3 |
|
|
|
174 |
|
|
|
|
1 388 |
|
|
|
3.3 |
|
|
|
150 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2005, Q-4 |
|
|
|
1 991 |
|
|
|
3.3 |
|
|
|
208 |
|
|
|
|
1 699 |
|
|
|
2.9 |
|
|
|
159 |
|
|
|
|
1 465 |
|
|
|
2.9 |
|
|
|
135 |
|
|
|
|
1 425 |
|
|
|
2.8 |
|
|
|
127 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
5 824 |
|
|
|
3.6 |
|
|
|
661 |
|
|
|
|
5 255 |
|
|
|
3.2 |
|
|
|
538 |
|
|
|
|
5 385 |
|
|
|
3.8 |
|
|
|
651 |
|
|
|
|
5 649 |
|
|
|
3.4 |
|
|
|
614 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Net stockpile changes |
|
|
|
(352 |
) |
|
|
2.3 |
|
|
|
(26 |
) |
|
|
|
(352 |
) |
|
|
2.3 |
|
|
|
(26 |
) |
|
|
|
(352 |
) |
|
|
2.3 |
|
|
|
(26 |
) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Adjusted Figures |
|
|
|
5 472 |
|
|
|
3.6 |
|
|
|
635 |
|
|
|
|
4 903 |
|
|
|
3.2 |
|
|
|
512 |
|
|
|
|
5 033 |
|
|
|
3.9 |
|
|
|
625 |
|
|
|
|
5 649 |
|
|
|
3.4 |
|
|
|
614 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2001 |
|
|
|
5 307 |
|
|
|
5.3 |
|
|
|
904 |
|
|
|
|
5 232 |
|
|
|
4.8 |
|
|
|
813 |
|
|
|
|
5 606 |
|
|
|
5.2 |
|
|
|
937 |
|
|
|
|
5 470 |
|
|
|
5.2 |
|
|
|
914 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2002 |
|
|
|
4 294 |
|
|
|
4.0 |
|
|
|
552 |
|
|
|
|
4 059 |
|
|
|
3.7 |
|
|
|
486 |
|
|
|
|
5 141 |
|
|
|
3.5 |
|
|
|
579 |
|
|
|
|
5 611 |
|
|
|
3.7 |
|
|
|
668 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2003 |
|
|
|
4 817 |
|
|
|
5.2 |
|
|
|
805 |
|
|
|
|
4 694 |
|
|
|
5.4 |
|
|
|
820 |
|
|
|
|
4 828 |
|
|
|
5.0 |
|
|
|
776 |
|
|
|
|
5 631 |
|
|
|
4.5 |
|
|
|
815 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2004 |
|
|
|
2 541 |
|
|
|
6.3 |
|
|
|
520 |
|
|
|
|
2 422 |
|
|
|
6.3 |
|
|
|
492 |
|
|
|
|
2 672 |
|
|
|
6.7 |
|
|
|
574 |
|
|
|
|
5 654 |
|
|
|
4.4 |
|
|
|
802 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2005 |
|
|
|
5 824 |
|
|
|
3.6 |
|
|
|
661 |
|
|
|
|
5 255 |
|
|
|
3.2 |
|
|
|
538 |
|
|
|
|
5 385 |
|
|
|
3.8 |
|
|
|
651 |
|
|
|
|
5 649 |
|
|
|
3.4 |
|
|
|
614 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
22 783 |
|
|
|
4.7 |
|
|
|
3 442 |
|
|
|
|
21 662 |
|
|
|
4.5 |
|
|
|
3 149 |
|
|
|
|
23 632 |
|
|
|
4.6 |
|
|
|
3 517 |
|
|
|
|
28 015 |
|
|
|
4.2 |
|
|
|
3 813 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Net stockpile changes |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(2 940 |
) |
|
|
2.1 |
|
|
|
(202 |
) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Adjusted Figures |
|
|
|
22 783 |
|
|
|
4.7 |
|
|
|
3 442 |
|
|
|
|
21 662 |
|
|
|
4.5 |
|
|
|
3 149 |
|
|
|
|
23 632 |
|
|
|
4.6 |
|
|
|
3 517 |
|
|
|
|
25 075 |
|
|
|
4.5 |
|
|
|
3 611 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Totals may not add due to rounding
63
Strathcona Mineral Services Limited
From the data in Table 11, the following conclusions can be drawn:
|
|
|
Because much of the ore from 2001 to 2004 and into 2005 originated in the more continuous
parts of the deposit, both the KS-5 and the KS-6 models perform adequately in forecasting mill
feed, showing the random variances that have been noted before. |
|
|
|
|
The underlying reason for the poor performance of the KS-5 model in the less continuous parts
of the Kumtor deposit is the inadequate drill hole and thus data density in those areas. If
the short-term variance of prediction versus actual performance remains unacceptably high for
another few quarters, then a change to shorter projection distances for the classification of
the resources and reserves may be in order. The solution to this situation is to double the
existing drill hole density in the areas in question. |
|
|
|
|
It is too early to judge the adequacy of the external dilution now incorporated into the KS-6
model. One must remember that the external dilution provision
described in Section 15.6 uses arbitrary assumptions about the amount of low-grade or waste to be added to
each block. Depending on the performance of the model for a larger tonnage, adjustments may have
to be made in this regard. |
|
|
|
|
Based on the data presented in Table 11, which shows both models to slightly under-estimate
the ore tonnage and the contained ounces, both models work well in the continuous parts of the
deposit. Based on the evidence to date, KS-6 performs better in the difficult parts, and may
turn out to be adequate. There is no indication that an independent resource/reserve estimate
by an external party would perform better, and is thus not required. |
15.13 Life-of-Mine Plan
Based on the estimate of mineral reserves as of December 31, 2005 (Table 10), KOC staff have
developed a Life-of-Mine (LOM) plan for the Kumtor and Southwest deposits and that is summarized in Table 12. Figure 10 shows the resultant ultimate Kumtor pit
outline and adjacent waste dumps.
64
Strathcona Mineral Services Limited
Table 12 Life-Of-Mine Plan and Production Forecast
thousands of tonnes of ore and waste and ounces of gold
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2006 |
|
|
2007 |
|
|
2008 |
|
|
2009 |
|
|
2010 |
|
|
2011 |
|
|
2012 |
|
|
2013 |
|
|
|
Total |
|
|
Mining
Kumtor Pit |
|
Ore |
|
tonnes |
|
|
|
5 426 |
|
|
|
5 540 |
|
|
|
3 580 |
|
|
|
4 393 |
|
|
|
5 985 |
|
|
|
5 834 |
|
|
|
|
|
|
|
|
|
|
|
|
30 759 |
|
|
|
|
|
|
|
|
g/t |
|
|
|
3.2 |
|
|
|
3.4 |
|
|
|
5.0 |
|
|
|
6.4 |
|
|
|
4.7 |
|
|
|
4.3 |
|
|
|
|
|
|
|
|
|
|
|
|
4.4 |
|
|
|
Low-grade |
|
tonnes |
|
|
|
973 |
|
|
|
587 |
|
|
|
608 |
|
|
|
533 |
|
|
|
954 |
|
|
|
892 |
|
|
|
|
|
|
|
|
|
|
|
|
4 547 |
|
|
|
|
|
|
|
|
g/t | |
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
|
|
|
|
|
|
|
|
|
1.4 |
|
|
|
Total |
|
tonnes |
|
|
|
6 399 |
|
|
|
6 127 |
|
|
|
4 188 |
|
|
|
4 926 |
|
|
|
6 939 |
|
|
|
6 726 |
|
|
|
|
|
|
|
|
|
|
|
|
35 306 |
|
|
|
|
|
|
|
|
g/t | |
|
|
2.9 |
|
|
|
3.2 |
|
|
|
4.5 |
|
|
|
5.9 |
|
|
|
4.2 |
|
|
|
3.9 |
|
|
|
|
|
|
|
|
|
|
|
|
4.0 |
|
|
|
Waste |
|
tonnes |
|
|
|
82 002 |
|
|
|
114 528 |
|
|
|
100 786 |
|
|
|
113 514 |
|
|
|
116 337 |
|
|
|
94 245 |
|
|
|
|
|
|
|
|
|
|
|
|
621 412 |
|
|
|
Strip |
|
|
|
|
|
|
|
12.8 |
|
|
|
18.7 |
|
|
|
24.1 |
|
|
|
23.0 |
|
|
|
16.8 |
|
|
|
14.0 |
|
|
|
|
|
|
|
|
|
|
|
|
17.6 |
|
|
|
|
|
|
|
|
Mining
Southwest Pit |
|
Ore |
|
tonnes |
|
|
|
972 |
|
|
|
489 |
|
|
|
805 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2 266 |
|
|
|
|
|
|
|
|
g/t | |
|
|
2.7 |
|
|
|
3.1 |
|
|
|
4.9 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
3.6 |
|
|
|
Low-grade |
|
tonnes |
|
|
|
198 |
|
|
|
159 |
|
|
|
145 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
502 |
|
|
|
|
|
|
|
|
g/t | |
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1.4 |
|
|
|
Total |
|
tonnes |
|
|
|
1 170 |
|
|
|
648 |
|
|
|
950 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2 768 |
|
|
|
|
|
|
|
|
g/t | |
|
|
2.5 |
|
|
|
2.7 |
|
|
|
4.4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
3.2 |
|
|
|
Waste |
|
tonnes |
|
|
|
11 382 |
|
|
|
10 271 |
|
|
|
6 507 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
28 161 |
|
|
|
Strip |
|
|
|
|
|
|
|
9.7 |
|
|
|
15.9 |
|
|
|
6.9 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
10.2 |
|
|
|
|
|
|
|
|
Total
Mining |
|
Ore |
|
tonnes |
|
|
|
6 398 |
|
|
|
6 029 |
|
|
|
4 385 |
|
|
|
4 393 |
|
|
|
5 985 |
|
|
|
5 834 |
|
|
|
|
|
|
|
|
|
|
|
|
33 025 |
|
|
|
|
|
|
|
|
g/t | |
|
|
3.1 |
|
|
|
3.4 |
|
|
|
5.0 |
|
|
|
6.4 |
|
|
|
4.7 |
|
|
|
4.3 |
|
|
|
|
|
|
|
|
|
|
|
|
4.3 |
|
|
|
Low-grade |
|
tonnes |
|
|
|
1 171 |
|
|
|
746 |
|
|
|
753 |
|
|
|
533 |
|
|
|
954 |
|
|
|
892 |
|
|
|
|
|
|
|
|
|
|
|
|
5 049 |
|
|
|
|
|
|
|
|
g/t | |
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
|
|
|
|
|
|
|
|
|
1.4 |
|
|
|
Total |
|
tonnes |
|
|
|
7 569 |
|
|
|
6 775 |
|
|
|
5 138 |
|
|
|
4 926 |
|
|
|
6 939 |
|
|
|
6 726 |
|
|
|
|
|
|
|
|
|
|
|
|
38 074 |
|
|
|
|
|
|
|
|
g/t | |
|
|
2.9 |
|
|
|
3.2 |
|
|
|
4.5 |
|
|
|
5.9 |
|
|
|
4.2 |
|
|
|
3.9 |
|
|
|
|
|
|
|
|
|
|
|
|
4.0 |
|
|
|
Waste |
|
tonnes |
|
|
|
93 384 |
|
|
|
124 799 |
|
|
|
107 293 |
|
|
|
113 514 |
|
|
|
116 337 |
|
|
|
94 245 |
|
|
|
|
|
|
|
|
|
|
|
|
649 573 |
|
|
|
Strip |
|
|
|
|
|
|
|
12.3 |
|
|
|
18.4 |
|
|
|
20.9 |
|
|
|
23.0 |
|
|
|
16.8 |
|
|
|
14.0 |
|
|
|
|
|
|
|
|
|
|
|
|
17.1 |
|
|
|
|
|
|
|
|
Stockpile
Changes |
|
Ore |
|
tonnes |
|
|
|
740 |
|
|
|
371 |
|
|
|
-1 127 |
|
|
|
22 |
|
|
|
337 |
|
|
|
177 |
|
|
|
-1 205 |
|
|
|
0 |
|
|
|
|
-685 |
|
|
|
|
|
|
|
|
g/t | |
|
|
1.6 |
|
|
|
1.2 |
|
|
|
1.7 |
|
|
|
2.8 |
|
|
|
1.6 |
|
|
|
1.6 |
|
|
|
2.0 |
|
|
|
|
|
|
|
|
2.8 |
|
|
|
Low-grade |
|
tonnes |
|
|
|
1 171 |
|
|
|
746 |
|
|
|
608 |
|
|
|
-753 |
|
|
|
944 |
|
|
|
892 |
|
|
|
-4 452 |
|
|
|
-894 |
|
|
|
|
-1 739 |
|
|
|
|
|
|
|
|
g/t | |
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
1.4 |
|
|
|
|
1.4 |
|
|
|
|
|
|
|
|
Milling |
|
Ore |
|
tonnes |
|
|
|
5 659 |
|
|
|
5 658 |
|
|
|
5 658 |
|
|
|
5 658 |
|
|
|
5 658 |
|
|
|
5 658 |
|
|
|
5 657 |
|
|
|
894 |
|
|
|
|
40 500 |
|
|
|
|
|
|
|
|
g/t | |
|
|
3.3 |
|
|
|
3.5 |
|
|
|
4.3 |
|
|
|
5.3 |
|
|
|
4.8 |
|
|
|
4.4 |
|
|
|
1.5 |
|
|
|
1.8 |
|
|
|
|
3.8 |
|
|
|
Recovery |
|
|
% |
|
|
|
76.2 |
|
|
|
82.9 |
|
|
|
86.7 |
|
|
|
87.4 |
|
|
|
87.1 |
|
|
|
78.5 |
|
|
|
74.2 |
|
|
|
70.6 |
|
|
|
|
83.0 |
|
|
|
Gold produced |
|
tonnes |
|
|
|
14.3 |
|
|
|
16.6 |
|
|
|
20.9 |
|
|
|
26.2 |
|
|
|
23.8 |
|
|
|
19.5 |
|
|
|
6.4 |
|
|
|
1.1 |
|
|
|
|
128.9 |
|
|
|
|
|
|
|
ounces |
|
|
|
461 |
|
|
|
533 |
|
|
|
674 |
|
|
|
843 |
|
|
|
764 |
|
|
|
627 |
|
|
|
206 |
|
|
|
37 |
|
|
|
|
4 144 |
|
|
|
|
|
|
|
|
The new mine plan extends the Kumtor mining operations into the second half of 2011 while
milling operations will extend through the first half of 2013, treating stockpiles in the last
eighteen months. While the total annual tonnage (ore plus waste) mined was in the range of 30
million tonnes per year from 1998 to 2000, it increased to 50 million tonnes in 2002 and to 75 to
80 million tonnes in recent years. The LOM plan predicts a further increase in annual total tonnage
mined starting in 2006, with a maximum of 131 million tonnes of ore plus waste reached in 2007.
Much of this is the result of the inclusion of the high-grade SB Zone in the Kumtor mineral
reserves, that requires a substantial amount of pre-stripping. The strip ratio will thus increase
from 12 : 1 in 2005 to range from 17 : 1 to 23 : 1 in the years 2007
to 2010. This
65
Strathcona Mineral Services Limited
reflects the high-grade character of the SB Zone and the low unit costs for mining waste
rock that have been demonstrated at Kumtor.
Included as waste in the LOM plan and production forecast are inferred resources of 440 000
tonnes with an average gold grade of over 7g/t that fall into the final pit design but were
treated as waste during pit optimization and are not included in the reserve estimate.
A new element at Kumtor is the mining of the Southwest deposit as a satellite operation,
which will take place from 2006 to 2008. If additional drilling at the Sarytor deposit
yields positive results, then the LOM plan allows for the inclusion of this second satellite
operation starting in 2009.
The gold production forecast for 2006 and 2007 is modest by Kumtor standards, but will reach
a new high in 2009, when the best part of the SB zone will be mined. The low gold production
in years 2012 and 2013 reflects the low-grade character of the stockpiled ore being milled.
16. |
|
POSSIBLE MINERAL RESERVE ADDITIONS |
Mineral reserve additions at Kumtor are possible from a variety of sources. They include
potential extensions of the current Kumtor pit to mine additional mineralization in the
northeastern part with a higher gold price, the possibility of underground mining in parts of
the deposit that fall outside the optimized final pit design, and additions from areas of
mineralization adjacent to, and on strike with, the Kumtor deposit within the Exploration
Licence surrounding the Concession Area.
|
16.1 |
|
Kumtor and Southwest Pit Extensions |
The Kumtor and Southwest mineral resources described in Section 15 include tonnages outside of the
ultimate pit design that are in addition to the reservessummarized in Table 10. These additional
mineral resources are set forth in Table 13 and include the mineral resources for the Sarytor
deposit for which no mineral reserves have yet been estimated.
66
Strathcona Mineral Services Limited
Table 13 Kumtor Mineral Resources in Addition to Mineral Reserves
|
|
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Contained Gold |
|
Category |
|
|
Tonnes |
|
|
Gold |
|
|
|
Ounces |
|
|
Tonnes |
|
|
|
|
(000s) |
|
|
(g/t) |
|
|
|
(000s) |
|
|
|
|
|
|
|
|
|
|
|
|
Measured |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Kumtor Open Pit (>1.3 g/t) |
|
|
|
13 406 |
|
|
|
3.8 |
|
|
|
|
1 634 |
|
|
|
50.8 |
|
Southwest Deposit |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Sarytor Deposit |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Indicated |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Kumtor Open Pit (>1.3 g./t) |
|
|
|
7 639 |
|
|
|
4.4 |
|
|
|
|
1 071 |
|
|
|
33.3 |
|
Southwest Deposit |
|
|
|
1 229 |
|
|
|
3.8 |
|
|
|
|
149 |
|
|
|
4.6 |
|
Sarytor Deposit |
|
|
|
1 733 |
|
|
|
3.0 |
|
|
|
|
167 |
|
|
|
5.2 |
|
|
|
|
|
|
|
|
Total Measured and Indicated |
|
|
|
24 007 |
|
|
|
3.9 |
|
|
|
|
3 021 |
|
|
|
93.9 |
|
|
|
|
|
|
|
|
Inferred |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Kumtor Open Pit (>1.5 g/t) |
|
|
|
1 009 |
|
|
|
6.5 |
|
|
|
|
210 |
|
|
|
6.5 |
|
Kumtor Underground (>5 g/t) |
|
|
|
1 636 |
|
|
|
6.6 |
|
|
|
|
347 |
|
|
|
10.8 |
|
Southwest Deposit |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Sarytor Deposit |
|
|
|
2 830 |
|
|
|
2.7 |
|
|
|
|
247 |
|
|
|
7.7 |
|
|
|
|
|
|
|
|
Total Inferred |
|
|
|
5 475 |
|
|
|
4.6 |
|
|
|
|
804 |
|
|
|
25.0 |
|
|
|
|
|
|
|
|
Estimates of additional resources potentially mineable by an expanded Kumtor open-pit have
been based upon a cut-off grade of 1.3 g/t gold using the undiluted KS-6 resource model. They occur
in the space between the current ultimate pit design and a larger pit shell (a resource shell) that
is judged by Centerra to offer the possibility of eventually being mineable following the
evaluation of a wide range of non-engineered pit shells. This process satisfies the CIM guidelines
that require mineral resources to offer reasonable prospects for economic extraction .
The resource shell shown in Figure 15 would recover nearly all of the additional measured and indicated mineral
resources in Table 13. However, the additional ore tonnage would only be released with a large
increase in the overall strip ratio. Additional ore is needed in the highwall to lower the
incremental strip ratio together with a higher gold price than was used in the current pit design.
A
similar resource shell defines the bottom to which additional mineral resources are reported for
the Southwest Deposit (Figure 8), and the Sarytor resources are also contained in such a pit shell.
67
Strathcona Mineral Services Limited
Additional underground resources for the Kumtor deposit are reported at a 5 g/t cut-off
grade, but are unconstrained and undiluted, in contrast to their counterpart reported for
the 2004 IPO. They are located outside of the resource shell and above elevation 3600
metres.
The
partial delineation of the NB Zone below the Kumtor pit highwall has
shown that potential exists to find additional mineralization in this area, identified as the Northend Target, an area with little previous drilling because of difficult access. As Figure 15
shows, the incremental strip ratio for this material is currently too high to allow its
inclusion in the Kumtor mineral reserves, but the discovery of additional ore-grade
mineralization to the north of the NB zone, particularly if it extended to surface, could
result in the layback of the highwall becoming economic to undertake by lowering the
incremental strip ratio in this part of the pit. This would result in a substantial part of
the additional open-pit resources, and possibly also of the
underground resources, in Table 13 being converted into open-pit reserves, in addition to any new Northend
mineralization. The drill program in the northeastern part of the pit is ongoing.
As at the Kumtor deposit, the additional mineral resources of the Southwest deposit are
contained between the mining design pit and a resource shell. The mineable portion of the
Southwest deposit is strongly influenced by the adverse topographical situation (Figures 8 and 13). The additional mineral resources would carry an incremental
strip ratio of 33 to 1 if converted to reserves. The discovery of additional ore-grade mineralization to the northeast of the current reserves toward the
Davidov glacier could help with the overall strip ratio for the deposit and force the pit
deeper than is currently the case. Drilling is planned for the summer of 2006.
Most of the Sarytor mineral resources are currently in the inferred category because of the
open drill pattern. The resources are constrained by a non-engineered resource shell that
used a gold price of $400 per ounce as described above with the same slope angles as used for the Southwest Deposit pit (Table 9). There is a good likelihood
that these resources can be upgraded to higher categories by the planned program of in-fill
drilling, and partly be converted to mineral reserves and added to the LOM plan.
|
16.2.1 |
|
Obligation to Evaluate Underground Mineral Reserves |
Under the Investment Agreement Centerra has agreed to undertake exploration and conduct
feasibility studies of the development of that portion of the Kumtor deposit which requires
underground mining. As part of that commitment, KGC agreed to spend $2.5 million on
assessing the underground exploration potential during 2004 and 2005. KGC must notify the
Government of the Kyrgyz Republic at least 24
69
Strathcona Mineral Services Limited
months
before the projected termination of open-pit mining as to whether it
will undertake
underground mining. If it does not, then the Government of the Kyrgyz Republic will have the
option to require KGC either to assign to the Government an interest in the Concession Area
sufficient to permit underground exploration and development, or to surrender such an
interest in the Concession Area back to the Government.
A part of the surface drill program undertaken at Kumtor in 2004 and 2005 was for the purpose of
outlining and defining, on an initial drill pattern, potential underground resources. KOC have
informed the Kyrgyz government (Melrose, 2005), that expenditures in 2004 were $1.5 million.
Exploration drilling expenditures for underground resources incurred in 2005 amount to $3.4 million for a total of $4.9 million, although
a formal report has not yet been issued. It appears that KGC have fulfilled their commitment with
respect to this item.
|
16.2.2 |
|
Underground Mineral Resources |
As described in Section 16.1, a resource shell delimits the additional resources below the current
ultimate Kumtor pit that may be mineable by an expanded open pit and that were therefore reported
at a cut-off grade of 1.5 g/t. Below this pit shell, underground mining would be the extraction
method (Figure 15). For the purpose of reporting mineral resources for possible underground mining,
the KS-6 block model was used at a 5 g/t cut-off grade below the low-NPV pit shell, but above the
3600-metre elevation, with the results summarized in Table 14.
Table 14 Mineral Resources Considered for Underground Mining
above 3600 metre elevation
|
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|
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|
|
|
|
|
|
|
|
|
|
|
Cut-Off Grade 5.0 g/t Gold |
|
|
|
Tonnes |
|
|
Gold |
|
|
Contained Gold |
|
Category |
|
(000s) |
|
|
(g/t) |
|
|
Ounces(000s) |
|
|
Tonnes |
|
Inferred |
|
1 636 |
|
|
6.6 |
|
|
347 |
|
|
10.8 |
|
|
The cut-off gold grade of 5.0 g/t is based on the application of preliminary operating costs.
The majority of this mineralization is in the NB Zone and shows reasonable grade continuity at the
elevated cut-off grade. There is very good potential for extending high-grade gold mineralization
of the SB zone to depth and along strike to the south, and at depth to the north. Given the
encroachment of the current final pit on the Davidov glacier as described in Section 15.10, most of such additional mineralization would
have to be considered for underground mining.
70
Strathcona Mineral Services Limited
However, it is recognized that the higher cut-off grade applied to the underground resources
compared to the pit resources requires a tighter drill pattern for this mineralization than
is currently in place, and all of the underground resources are therefore classified as
inferred until in-fill drilling can be done.
The resource estimate in Table 14 does not yet fully reflect the underground mining
approach, as provisions for mining losses and mining dilution appropriate to the expected
poor ground conditions are not included. Underground mining at Kumtor would have to occur in
conjunction with open-pit mining, as an underground operation alone would not match the
capacity of the
15 000-tonne-per-day mill.
An earlier preliminary study (Cameco, 1999) had concluded, on the basis of less drill
information than is available today, that underground mining at a rate of 2000 tonnes per
day would be both technically and economically feasible, using cut- and-fill methods (both overhand and underhand). The ground conditions are expected to be
very poor, and the mining would amount to trying to recover harder ore in a very soft,
faulted and sheared environment that would require the use of extensive and expensive ground
control measures.
While drilling for underground resources centred on the high-grade SB and NB Zones is
continuing into 2006, with potential for of identifying additional resources in both areas,
KOC plans to conduct a scoping study in 2006 as the next logical step that would define an
underground mining approach, the production rate, operating and capital costs for an
eventual underground operation. The investigation would include cross-over studies with the
aim of establishing where underground mining below the ultimate design pit becomes more
advantageous than open-pit mining at a high strip ratio, and would thus investigate all
known mineralization below the KS-6 design pit.
Given the poor ground conditions, there can be no assurance that these studies will have a
positive outcome. In any event, trial underground development and mining will have to be
successfully conducted before underground mineral reserves can be reported at Kumtor.
KGC controls the Exploration Licence, which has recently been renewed as described
in Section 3 and as shown in Figure 3. There are several exploration targets along strike in
both directions from the Kumtor deposit, which will be briefly described in this section.
The areas to the southwest of Kumtor have the disadvantage of the structure that controls
the mineralization dipping at shallow to intermediate angles to the southeast, with the
surface rising in the same direction. Access to the deeper parts of gold mineralization in
this area by open-pit mining is therefore limited by the
71
Strathcona Mineral Services Limited
adverse topographical situation. However, owing to the proximity of these areas to the
existing mine infrastructure, capital costs to develop a satellite deposit would be low.
To the northeast from the Kumtor pit is the Northeast Area (Figure 4), where surface
trenching, diamond drilling and underground workings in the 1980s resulted in Soviet
determination of inferred resources mineable by open pit of 1.7 million tonnes with an average grade of 2.3 g/t gold. These figures are not in compliance
with current resource and reserve reporting requirements, but are mentioned to show the
possible scope of this area. While KOC have conducted little additional physical work,
ongoing work has included the addition of the Northeast Area data into the exploration
database, limited surface trenching and the re-interpretation of the geology and the earlier
exploration results in light of the knowledge gained at Kumtor since mining started. While a
few targets for drilling have been identified, they are of a lower priority, given the
positive results elsewhere.
Further to the southwest of Sarytor is the Bordoo area, where targets identified by
geophysical surveys conducted during the Soviet period were tested in 1999 by surface
sampling. The best results of surface chip sampling were 20.3 g/t gold over 5 metres and 3.6
g/t gold over 20 metres. There is also a previously unexplored gap of approximately three
kilometres strike length between the Sarytor and Bordoo targets. Some 850 metres of
trenching and outcrop sampling conducted in this area in 2002 has given initial encouraging
results, such as 1.0 g/t gold over 8.0 metres in trench T-BR 2 and 2.4 g/t gold over 5.0
metres in trench T-BR 13. Numerous mineralized outcrop and road cut samples have outlined an
800-metre by 50 to 70-metre zone of generally low-grade gold mineralization, with values
from 0.5 to 1.0 g/t gold over 5.0 metres (chip sample) and 8.42 g/t gold over 2.0 metres
(chip sample).
An induced polarization (IP) survey was completed over the Sarytor and Bordoo areas,
extending the historic IP coverage to the southwest. The data show the continuation of the
Kumtor Fault under the moraines covering the northern part of the Sarytor and Bordoo areas.
A geo-electrical response similar to that found at Sarytor has also been detected in the
Bordoo area, extending the possible structural target area approximately three kilometres
along strike to the southwest. The interpreted zone is covered by the moraine and needs to
be tested by drilling.
The Akbel area is situated furthest along strike to the southwest from the Bordoo area.
Reconnaissance exploration work which included geophysical surveys, geologic
72
Strathcona Mineral Services Limited
mapping and surface sampling indicated the presence of some gold mineralization, with the
best result being an assay of 3.0 g/t gold from a grab sample. This area is
currently of lower priority, but requires additional surface exploration programs. It is
of note that the activities of Kentor Gold Limited as described in Section 13 are contiguous
with the Akbel area. Current activities include the drilling of several core holes on a
geochemical anomaly some 13 kilometres to the southwest of the Kumtor mill (Kentor, 2005).
|
16.4 |
|
Planned 2006 Exploration Expenditures |
The description in the previous sections of the remaining exploration possibilities at and
around the Kumtor operation make clear that a program of additional exploration, mostly in
the form of surface drilling, is justified and required to fully evaluate the various
targets, with a good chance to add to the life of the Kumtor mine operation. KOC currently
has eight owned and two national contractor drills that, together, can complete about 75 000
metres per year. The exact number of holes drilled on each of the targets in 2006 will
depend on a combination of seasonal access, mine operational and target priority
considerations. Centerra has approved a budget of $11.4 million for these activities in
2006, with the proviso that, depending on results, additional funds may be made available.
It is likely that the approved budget will not be sufficient to account for the total drill
capacity currently available at Kumtor.
Given the ongoing success of the surface drill campaigns at Kumtor in the past three years,
the number of exploration targets that remain to be tested, and taking into consideration
that an underground development program will be required to fully evaluate the feasibility
of underground mining, substantial exploration and development commitments will be required
over the next few years at Kumtor.
17. |
|
ADDITIONAL INFORMATION FOR PRODUCTION PROPERTIES |
Mining operations at Kumtor are carried on using conventional open-pit mining methods with
2005 mine production being at the rate of 17 000 tonnes per day (tpd) of ore including
low-grade material to stockpiles, and 205 000 tpd of waste. The initial stripping of the
Kumtor orebody in 1995 had the unusual challenge of mining a portion of the Lysyi Glacier
that covered the northeastern area of the planned open pit, and lesser quantities of ice
have been removed in subsequent years as the northeast highwall of the open pit is pushed
back.
73
Strathcona Mineral Services Limited
The Kumtor open pit has had the benefit of a favourable topographical situation. The top
mining elevation in the current ultimate pit design is at about 4460 metres, and the very
deepest part will be at 3620 metres in the southwest part of the deposit
(Figure 10). The crushing plant to which ore is delivered is at about 4050 metres and ore
transport was thus downhill for the upper portion of the orebody, and will have a maximum
uphill haul of 400 metres for the lower portion.
Waste disposal has been greatly facilitated by the proximity of suitable areas for waste
dumps adjoining the pit to the northwest and to the east. In both of those areas a portion
of the waste is deposited on glaciers that exhibit some flow as a result of the increasing
load. The ice movement is measured and monitored. The special situation with respect to the
Davidov glacier and the southwestern part of the Kumtor ultimate
pit has been described in Section 15.10. The waste does not have any acid generation
potential because of its high carbonate content. The favourable topographical setting for
movement of both ore and waste is the principal reason for the low unit costs for mining at
Kumtor.
Mining is based on eight-metre benches with blast hole drilling using nine diesel-powered
Drilltech D45KsH rotary-percussion drill rigs. Recently, split-bench mining has been
introduced in areas of lower ore thickness. Charging the holes is performed with special
bulk explosives trucks delivering either ammonium nitrate with fuel oil (ANFO), or emulsion
explosives for wet holes. The explosives consumption is about 0.75 kg per cubic metre of ore
or waste.
The main loading fleet includes eight CAT 5130 B hydraulic excavators, seven of which are
configured as shovels, the other as a backhoe, and three CAT 992C front-end loaders. Nominal
bucket capacities are 11.0 cubic metres and 10.3 cubic metres, respectively. Typically, the
shovels are used for production and the loaders for ore blending, cleanup and support during
shovel maintenance.
The haulage fleet consists of 39 CAT 777 B haul trucks with a calculated load factor of 78
tonnes. Eleven tracked and rubber-tired dozers are used for the maintenance of waste dumps,
operating bench floors, cleaning of safety benches and general clean-up for shovels, on
roads and blast patterns. Seven road graders maintain roadways and bench floors. One CAT 777
B haul truck has been converted to a 30 000-litre water truck for dust suppression.
Due to the very substantial increase in waste tonnages scheduled for the years 2006
to 2011 and the mining of the Southwest Deposit (Table 12), an increase in the mining fleet
is scheduled for the next few years. This is summarized in the following table:
74
Strathcona Mineral Services Limited
Table 15 Major Pit Equipment Additions and Deletions, 2006 to 2012
|
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Additions (Deletions) |
|
|
|
Current |
|
|
2006 |
|
2007 |
|
2008 |
|
2009 |
|
2010 |
|
2011 |
|
2012 |
|
|
|
|
|
|
|
777 B Trucks |
|
|
|
39 |
|
|
|
|
0 |
|
|
|
0 |
|
|
|
-4 |
|
|
|
0 |
|
|
|
-19 |
|
|
|
-11 |
|
|
|
0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
785 Trucks |
|
|
|
0 |
|
|
|
|
8 |
|
|
|
16 |
|
|
|
6 |
|
|
|
2 |
|
|
|
0 |
|
|
|
-9 |
|
|
|
-23 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
5130 Excavators |
|
|
|
8 |
|
|
|
|
1 |
|
|
|
0 |
|
|
|
-1 |
|
|
|
-1 |
|
|
|
-1 |
|
|
|
-1 |
|
|
|
-4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Liebherr 994 B Shovels |
|
|
|
0 |
|
|
|
|
0 |
|
|
|
4 |
|
|
|
0 |
|
|
|
0 |
|
|
|
0 |
|
|
|
0 |
|
|
|
-4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Front-end loaders |
|
|
|
3 |
|
|
|
|
0 |
|
|
|
0 |
|
|
|
0 |
|
|
|
0 |
|
|
|
0 |
|
|
|
0 |
|
|
|
-1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Drills |
|
|
|
9 |
|
|
|
|
0 |
|
|
|
3 |
|
|
|
-1 |
|
|
|
-1 |
|
|
|
0 |
|
|
|
-2 |
|
|
|
-7 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Dozers |
|
|
|
11 |
|
|
|
|
1 |
|
|
|
4 |
|
|
|
-1 |
|
|
|
-1 |
|
|
|
0 |
|
|
|
-2 |
|
|
|
-9 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Graders |
|
|
|
7 |
|
|
|
|
0 |
|
|
|
3 |
|
|
|
-1 |
|
|
|
0 |
|
|
|
0 |
|
|
|
-2 |
|
|
|
-4 |
|
|
|
|
|
|
|
|
Equipment deleted will be retired or offered for re-sale.
Total capital costs for the years 2006 to 2011 are estimated at $132 million, the majority of
which will be spent to purchase the additional open-pit equipment. All major capital mining
equipment will be purchased new, as this represents the lowest unit operating and maintenance cost
option. A total of $118 million in capital expenditures will be made in 2006 and 2007.
Hydrological conditions are controlled by the presence of up to 250 metres of permafrost.
Supra-permafrost groundwater occurs in a thin thaw zone near surface, active only from July to
October. Groundwater volumes from this zone are relatively small and are included with the water
volumes handled as surface runoff and glacial meltwater. Surface waters are diverted away from the
pit using diversion ditches, sumps and gravity pipelines.
The permafrost boundary is between elevations 3900 and 3950, and parts of the pit are now in
unfrozen ground. The experience with the water handling system used in the pit has been good for
the current conditions. Water within the pit is channelled to sumps along dewatering ditches and is
then pumped outside of the pit limits. Diesel generators supply power for the pumps and spare pumps
are kept on site in the event of a pump failure.
Grade control in the pit is performed by sampling of the blasthole cuttings and blasted rock is
then sorted by grade and characteristics affecting processing and delivered to the primary crusher
or to the appropriate stockpile.
75
Strathcona Mineral Services Limited
Table 16 Material Destination by Grade and Type
|
|
|
|
|
|
Designation |
|
Gold Grade Range (g/t) |
|
|
Destination |
Ore
|
|
> 1.5 g/t
|
|
|
Crusher and crushed ore stockpile |
|
|
> 1.5 g/t
|
|
|
Refractory and carbonaceous stockpile |
|
|
> 1.5 g/t
|
|
|
Regular ore stockpile |
|
|
> 1.5 and < 2.0 g/t
|
|
|
Medium grade stockpile |
Low-grade
|
|
>1.3 and <1.5
|
|
|
Mostly stockpiled for later milling |
Sub-grade
|
|
>1.0 and <1.3
|
|
|
Stockpile, not scheduled for milling |
Waste
|
|
<1.0
|
|
|
Dumps on Davidov and Lysyi glaciers |
|
This ore-sorting program establishes the level of 1.3 g/t gold as the effective incremental
cut-off grade of the operation. At the end of December 2005, the low-grade stockpile contained 1.7
million tonnes with an average grade of 1.4 g/t gold, and the sub-grade stockpile was 2.8 million
tonnes with an average grade of 1.1 g/t gold. The cut-off grade for ore has been at the level of
1.5 g/t since 2004, and was at levels of 1.6 to 1.7 g/t from 1996 to 2000, reflecting the higher
unit operating costs and lower gold prices at the time.
Bench composites of diamond drill core are tested in the mill laboratory with respect to their
metallurgical character, and refractory and carbonaceous ore are delineated on this basis and kept
on separate ore stockpiles to allow blending. This data is also included in the block model used
for resource and reserve estimation and determines in part the value of a block. In general, the
northern part of the Kumtor deposit has the poorest recoveries, and higher grades are matched with
higher recoveries. The Southwest deposit shows recoveries that are generally inferior to those
experienced in the Kumtor deposit. The metallurgical information is included in data used for pit
optimization (Table 7).
The blasthole assay data are combined into an ore control model that is used to determine the dig
lines for the various grade categories and to estimate the monthly pit production. The ore control
model is further used for short and medium-term planning as monthly forecasts of tonnes and grade
by the resource block model have a variance that is too high for small tonnages. Finally, logging
of the blasthole chips allows the intensity of the alteration to be mapped, an important input
parameter into the definition of the structural ore zones that in turn play an important role in
the resource estimation process.
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Strathcona Mineral Services Limited
Extensive metallurgical testing was completed by Kyrgyz Geology from 1981 until
1989. During the Feasibility Study, Kilborn completed additional test work. The
flowsheet (Figure 16) reflects the fine-grained nature of the gold and its intimate
association with pyrite, and consists of crushing, grinding, pyrite flotation, and double
re-grinding of the flotation concentrate. Two separate carbon-in-leach (CIL) circuits
extract the gold from the re-ground concentrate and from the flotation tails, with final
gold recovery accomplished by electrowinning and refining. The mill was originally designed
with a capacity to process 4.8 million tonnes of ore per year. The mill throughput currently
is 5.5 million tonnes per year.
The ore to be milled is managed through a number of stockpiles that receive ore of different
metallurgical characters and of different grade ranges and thus allow blending of the mill
feed for optimum gold recovery. Ore fed to the crushing circuit is drawn from a live ore
stockpile. A gyratory crusher reduces the ore to 100% minus 30 centimetres. The ore is then
fed to a coarse ore stockpile from which it is reclaimed for grinding, first to a
semi-autogenous (SAG) mill and then to a ball mill, which together reduce the grain size to
80% passing 140 microns. A bulk sulphide concentrate representing 7 to 11% of the original
mill feed is produced with a grade of 30 to 50 g/t gold, about ten times the mill head
grade, and a gold recovery of 87 to 92% into the concentrate.
The flotation concentrate is re-ground to 90% passing 20 microns. After thickening to 60%
solids, it is once more re-ground to 95 to 98% passing 20 microns in an ISA mill that was
commissioned in October 2005. The ISA mill provides additional liberation of the fine
refractory gold (2-5 microns) enclosed in pyrite.
To ensure high-efficiency leaching of the re-ground concentrate, the number of tanks for
concentrate aeration was increased from one to two. Additional aeration is expected to
provide increased leach recovery by 2-5% without additional sodium cyanide consumption.
The concentrate is re-pulped to 45% solids, pre-aerated for 40 hours and leached for 80
hours in the CIL circuit consisting of four agitated tanks in series. Cyanide solution,
slaked quicklime and activated carbon to maintain a concentration of 14 grams per litre
(g/l) carbon, are added to the CIL circuit.
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Strathcona Mineral Services Limited
The flotation tailings with an average grade of 0.45 g/t gold are thickened to 50% solids
and subjected to cyanidation for 10 hours in a CIL circuit (three tanks) similar to the
circuit used for the sulphide concentrate but using a carbon concentration of 8 g/l. The
carbon in both CIL circuits is forwarded counter-current to the slurry flow, and the loaded carbon from the first flotation tailings CIL tank
is pumped to the third concentrate CIL tank to continue loading. Loaded carbon from the
first concentrate CIL tank is pumped to the gold recovery plant. The loaded carbon is
stripped and the gold subsequently recovered by electrowinning.
Process control is provided by the Foxboro System, which allows the monitoring and control
of the entire process. Six automatic samplers recover representative samples from all
circuits. An automatic reagent addition system optimizes the performance of the flotation
circuit. A particle-size monitor for the re-ground concentrate informs about any failures in
the grinding process in real time and thus reduces gold losses related to poor grinding. An
automatic analyzer in the CIL circuit helps to maintain the optimum levels of sodium cyanide
concentration and of the pH.
Tailings from the CIL circuits for both concentrate and flotation tailings are combined and
discharged by gravity to the tailings disposal area through a slurry pipeline (Figure 3).
Gold recovery in the CIL circuits is 30% for the flotation tailings and 90% for the sulphide
concentrate. Overall, 90% of the recoverable gold is won in the pyrite concentrate CIL
circuit, the remainder in the tailings CIL circuit.
Gold recovery during the early phase of the Kumtor operation was affected by the
preg-robbing character of some of the ore because of its active graphite which has been
moderated by adding diesel fuel and sodium laurel sulphate as masking agents to the ore
delivered to the SAG and the re-grind mills. Historically, the overall metallurgical
recovery of gold in the Kumtor mill has averaged 79%, but since 1999 has averaged 80.5% and
is expected to increase in future because of the recent installation of the ISA mill except
when low-grade stockpile ore or highly carbonaceous material is treated. Projected future
average annual gold recoveries are shown in Table 12.
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Strathcona Mineral Services Limited
|
17.4 |
|
Tailings Management Facility |
The tailings management facility is in the Kumtor River valley (Figure 3) and consists of
twin tailings pipelines, a tailings dam, an effluent treatment plant and two diversion
ditches around the area to prevent runoff and natural watercourses
from entering the tailings basin. These facilities received approval from the Government of
the Kyrgyz Republic during 1999. Each tailings pipeline is approximately six kilometres in
length. The tailings dam was designed and constructed to address the permafrost conditions
at the mine site and to standards for seismic activity in the region. The dam is
approximately two kilometres in length and up to 27 metres in height. It is constructed from
alluvial material along with a synthetic liner 100 metres on the upstream slopes. During
construction the alluvial material was compacted to the required density to provide
stability for the dam.
The tailings dam was designed to accommodate the projected requirements for tailings storage
for the life of the mine, and can readily be expanded if necessary to accommodate additional
mine production.
As of early January 2006, the tailings dam held 31.2 million cubic metres of tailings and
1.4 million cubic metres of untreated process water. The average length of the tailings
beach from the dam to the pond was 600 metres. During summer operations, some five million
cubic metres of effluent are treated and subsequently discharged into the environment.
Projected final tailings content in accord with the current LOM plan is 57.5 million cubic
metres, to be reached at the end of 2013.
An ice-rich silt layer about two metres below the original land surface has been the cause
of minor but persistent movement of the tailings dam, at a rate of 40 millimetres (mm) per
year. In 2003, a shear key was constructed for 700 metres along the toe of the dam by
excavating a trench nominally 6 metres deep and 20 metres wide and filled with compacted
granular fill. A five-metre berm of well-compacted granular fill was then constructed over
the shear key. The shear key is designed to interrupt and replace the ice-rich silt layer
along the downstream dam toe within the area of measured movement, with a high-strength,
stiff structure of sufficient width to eventually stop the movement of the dam.
Subsequent monitoring of the dam has shown that the remedial actions taken in 2003 have not
slowed the rate of creep of the dam, with the lower slope of the dam overriding the shear
key. Cumulative movement since 1998 is in the order of 200 mm, and, if it continued at that
rate, would ultimately endanger the integrity of the dam after closure of the mine.
BGC Engineering (2005b) have proposed the installation of an additional shear key in front
of the original shear key, as soon as practicable, and before any more fill is added
80
Strathcona Mineral Services Limited
to raise the tailings dam any further (BGC Engineering 2005b, page 10). KOC have
developed plans for the installation in 2006 of the additional shear key with a width of 50
metres plus a buttress that will rise 14 metres above the original ground for the central
portion of the dam. The eastern part would be built in 2007/08 to the same specification.
BGC are of the opinion that the new shear key will halt the creep within a period of time
that is still being modelled. Unless halted, the tailings dam movement constitutes a
long-term risk for the after-closure period of the operation.
Installation of the additional shear keys is estimated to cost $7.0 million from 2006 to
2008, and Centerra have indicated that these funds are firmly budgeted. Raising of the dam
to its final elevation will require an additional $5.8 million from 2006 to 2010.
|
17.5 |
|
Maintenance and Services |
The maintenance department is responsible for 87 major pieces of mine equipment, the 15
000-tonne-per-day process plant, the effluent treatment plant and the electrical
distribution system. The department is also responsible for approximately 128 pieces of
transportation equipment hauling supplies to and from the Kumtor mine site from the
marshalling yard in Balykchy.
KOC has utilized a computerized maintenance system since startup for mobile and plant
maintenance requirements. Initially schedules were set up in accordance with the
manufacturers specifications but as the component history developed, the preventative
maintenance schedules were adjusted where required. Work orders are used to control and
track all maintenance employee and materials costs.
The mechanical availability for the process plant is over 94% for the past two years and the
production mining fleet mechanical availability averages 90%. A comprehensive training
program that focuses on the transfer of mechanical, electrical, diagnostics and planning
skills from the expatriates to the national workforce has been very successful.
Power is provided from the Kyrgyz national grid under the Priority Power Supply Agreement.
Power generation in the Kyrgyz Republic is from hydro and thermal plants. A new power line
was constructed for the Kumtor project from Barskaun to Kumtor with financing arranged by
some of the Agency Lenders involved in the Kumtor project financing.
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Strathcona Mineral Services Limited
At December 31, 2005, the operation employed a total of 1653 permanent employees,
distributed by department and by citizenship as follows:
Table
17 Summary of Kumtor Personnel, December 31, 2005
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Department |
|
|
Kyrgyz Citizens |
|
Expatriates |
|
Total Employees |
|
|
|
|
Mining |
|
|
|
551 |
|
|
|
4 |
|
|
|
555 |
|
Milling |
|
|
|
130 |
|
|
|
13 |
|
|
|
143 |
|
Maintenance |
|
|
|
247 |
|
|
|
27 |
|
|
|
274 |
|
Camp & Site Administration |
|
|
|
449 |
|
|
|
23 |
|
|
|
472 |
|
Bishkek Administration |
|
|
|
200 |
|
|
|
9 |
|
|
|
209 |
|
|
|
|
|
Total |
|
|
|
1 577 |
|
|
|
76 |
|
|
|
1 653 |
|
|
|
|
|
The proportion of Kyrgyz citizens in the permanent work force is now 95%, having increased
from 82% at the beginning of the operation as a result of the training programs that KOC has
conducted, and reflects a policy of involving citizens of the Kyrgyz Republic at all levels in the
workforce as soon as the necessary skills and experience have been acquired. Under the Investment
Agreement, KGC must use commercially reasonable efforts to increase the percentage of citizens of
the Kyrgyz Republic in its workforce.
Not included in Table 17 are 229 temporary and permanent Kyrgyz contractors that perform a variety
of tasks, and also excluded are the 26 expatriate staff (mostly drillers), 58 Kyrgyz nationals, and
280 contract employees in the exploration department.
The increase in pit production necessitated by the pre-stripping of the SB Zone, and to a smaller
extent by the mining of the Southwest deposit as a satellite operation, will require additional
personnel in the years 2006 to 2010. The LOM plan projects employment at the following levels:
Table
18 Kumtor Personnel, 2006 to 2012
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2006 |
|
|
|
2007 |
|
|
|
2008 |
|
|
|
2009 |
|
|
|
2010 |
|
|
|
2011 |
|
|
|
2012 |
|
|
|
|
|
Kyrgyz Employees |
|
|
|
1 788 |
|
|
|
2 040 |
|
|
|
2 021 |
|
|
|
1 968 |
|
|
|
1 803 |
|
|
|
1 550 |
|
|
|
1 166 |
|
Kyrgyz Contractors |
|
|
|
90 |
|
|
|
94 |
|
|
|
94 |
|
|
|
90 |
|
|
|
90 |
|
|
|
90 |
|
|
|
90 |
|
Expatriates |
|
|
|
86 |
|
|
|
69 |
|
|
|
58 |
|
|
|
50 |
|
|
|
41 |
|
|
|
34 |
|
|
|
31 |
|
|
|
|
|
Totals |
|
|
|
1 964 |
|
|
|
2 203 |
|
|
|
2 173 |
|
|
|
2 108 |
|
|
|
1 934 |
|
|
|
1 674 |
|
|
|
1 287 |
|
|
|
|
|
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Strathcona Mineral Services Limited
Under this plan, the percentage of expatriates would decline from 4.4% in 2006 to about
one-half that in 2009 and remain at that level to the projected end of the operation.
|
17.7 |
|
Permits and Licences |
All mining activities at Kumtor are carried out in accordance with licenses and permits
issued by Kyrgyz government agencies based on the laws of the Kyrgyz Republic. KOC staff of
the Environmental and Policy & Compliance Departments spend considerable time and resources
ensuring that all permits and licenses are received and remain current. The Investment
Agreement provides that KGC is entitled to all licences, consents, permits and approvals of
the Government of the Kyrgyz Republic necessary for the operation of the Kumtor project,
including all matters with respect to meeting the requirements of legislation for protection
of the environment.
The Law on Protection of Atmospheric Air dated June 12, 1999 requires that each Kyrgyz
enterprise with activity that has a potential negative impact on the environment must
develop and maintain an ecological passport (Ecological Passport) providing for the basic
levels of impact on the environment, including the level of Maximum Allowable Emission (MAE)
and Maximum Allowable Discharge (MAD). The Ecological Passport is developed by an enterprise
every five years in accordance with the standards approved by the Government every five
years and must be approved by the Kyrgyz Ministry of Ecology and Emergency Situations
(Ministry of Ecology). The current Ecological Passport for KOC was developed by KOC and
approved by the Ministry of Ecology on November 24, 2004. The passport is valid for a
five-year period and is subject to renewal in November 2009.
The Ecological Passport identifies some of the permits and approvals required by KOC for its
operations, with annual permits required for MAE and MAD. The MAE permit regulates the
release of emissions into the air. There are two MAD permits regulating the discharge of
effluents into surface water bodies, one to operate the tailings area treatment plant and
the other to operate the sewage treatment plant. The MAE and MAD permits must be renewed
annually within the first quarter of each year, and are designed to ensure that the water
quality standards for communal use streams are met at the end of the mine site mixing zone
in the Kumtor River. KOC received the current MAE on April 8, 2005 and the current MAD
permits on April 26, 2005. Both are valid for one year until April 2006. KOC expect to have
the 2006 MAD permits in hand prior to commencing discharge of treated effluents or treated
sewage into the Kumtor River in May 2006.
Since May 2002, KGC has paid an environmental protection tax, for which the rate and method
of determination are defined by the Government and approved by the
83
Strathcona Mineral Services Limited
Parliament. The tax is comprised of payments for discharge of hazardous substances, air
emissions and water discharges and is forwarded to the Kyrgyz state fund for environmental
protection. In 2005, the environmental protection tax paid by KGC was $64 000.
On January 17, 2004 KOC received a license for disposal of tailings and a license for
disposal of toxic wastes to tailings areas, both valid until January 17, 2007.
Each potentially toxic chemical substance used at the Kumtor mine must be registered with
the Kyrgyz Republic Ministry of Health. The registration procedure includes a notice to be
sent by KOC each time a new potentially toxic chemical substance is used. The transportation
route for dangerous goods such as chemicals and blasting materials must be approved every
six months. The approval includes permits for the vehicles transporting the specific
material.
Blasting materials and sodium cyanide are imported from outside the Kyrgyz Republic and
require a license issued by the Kyrgyz Republic Ministry of Internal Affairs upon agreement
with a number of government departments. Such licenses are issued for one year. The current
licenses are valid until May 25, 2006.
The water usage permit for drawing water from Petrov Lake was renewed on December 19, 2005
and remains valid until December 20, 2006. This water permit covers both the site and
Balykchy marshalling yard and allows KOC to draw 6.3 million cubic metres of water per year
from Petrov Lake, which provides the requirements for milling and camp operations.
|
17.8 |
|
Environmental Management System |
In 2000, KOC developed a formal Environmental Management System (EMS) following the
ISO-14001 standards for determining and managing environmental aspects associated with its
activities. The EMS addresses all impacts of the operation on the environment and monitors
compliance with the various permits issued by the Kyrgyz authorities. The system provides
scheduled monitoring, engineering controls and reporting on the following areas:
|
|
|
effluent treatment plant; |
|
|
|
|
tailings management facility; |
|
|
|
|
mill site and mine waste dumps runoff effluents; |
|
|
|
|
acid generation potential testing and recommendations; |
|
|
|
|
dust control; |
|
|
|
|
spill incidents on site and off site; |
|
|
|
|
hazardous materials handling; |
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Strathcona Mineral Services Limited
|
|
|
environment impact monitoring; |
|
|
|
|
planning for site decommissioning and rehabilitation; |
|
|
|
|
potable water treatment system; |
|
|
|
|
sewage operation; and |
|
|
|
|
landfill operation and inventory. |
Since July 2004, KOC had two external systems audits. An EMS Audit was conducted by the Quality
Management Centre (QMC)/Pragma/USAID (Almaty, Kazakhstan) in November 2004 to confirm conformity
with ISO 14001:1996. Based on the audit of the five elements selected, it was demonstrated that the
EMS has been implemented and maintained. An assessment of the tailings management system described
in Section 17.4 was done using Mining Association of Canada (MAC) guidelines by (BGC Engineering
2005a). The results of the audit showed that KOC conformed to the MAC guidelines and that the KOC
tailings management facility is being managed comprehensively and effectively but identified a few
items where improvements are possible. The question of the stability of the tailings dam is also discussed in Section 17.4.
In May 1998, a truck operated by KOC en route to the Kumtor gold mine accidentally overturned and
spilled approximately 1760 kilograms of sodium cyanide into the Barskaun River, which in turn drains into Lake Issyk-Kul (Figure 2). This spill incident resulted
in extensive review of the mines Emergency Response Plan (ERP) and its hazardous material
transportation procedures by local authorities, lending agencies and KOC. A revised ERP took effect
December 1999. Since then, KOC has conducted quarterly mock exercises to test different aspects of
the ERP including response time, effective communications and the skills of the emergency response
team. The ERP has been updated and approved annually to ensure notification protocols remain valid
and improvements from the mock exercises are incorporated in the plan.
|
17.9 |
|
Environmental Management Action Plan |
As part of its obligations to the original lending institutions in connection with the Kumtor
project financing, KGC implemented an Environmental Management Action Plan (EMAP) in 1995. The EMAP
outlines KGCs environmental and safety commitments, including the regulations applicable to the
Kumtor project. The EMAP was updated in 1999 and again in 2002 to reflect the maturing operations.
The Investment Agreement provides that KGC will continue to be obligated to operate in accordance
with mine and operating plans that seek to limit the environmental impact of the project and
protect human health and safety in accordance with good
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Strathcona Mineral Services Limited
international mining practices. Specifically, KGC will continue to be obligated to operate
in material compliance with the standards applicable under the EMAP in effect as of the date
of the Investment Agreement, even though it may no longer be obligated to its lenders to do
so.
The standards applicable include the most stringent of :
|
|
|
The environmental laws of the Kyrgyz Republic and the current KGC Occupational Health and
Safety guidelines; and |
|
|
|
|
The World Bank Environmental Guidelines and the environmental laws of Canada and Saskatchewan
in effect as at June 15, 1995. |
KOC produced an environmental report for 2004 (KOC, 2005) that describes the programs underway.
Much of the work consists of additional data gathering ...to comply with the current EMAP and
to support the 2002 External Environmental Audit recommendation to ensure that background studies are done on Exploration target areas around the mine site. (KOC 2005). As part of this program, new stations have been added in
the EMAP monitoring program to detect any adverse impacts related to the exploration and
development of the Southwest deposit. Benthos Studies have been set up to assess any long term
impact of KOCs treated effluent and sewage discharges in the Kumtor River by comparing it to
background data being obtained from the undisturbed Bordoo and Akbel creeks, tributaries to the
Kumtor River. It was found that because of the suspended solids from the meltwater component there
was a very restricted benthic fauna in these creeks. Environmental studies are continuing,
addressing such diverse questions as waste rock characterization of exploration areas and
investigations of the Barskaun forestry.
The Kumtor project continues to be operated in compliance with all regulations and reporting
protocols outlined in the EMAP. Centerra have issued a formal letter (Lewis, 2006) stating that the
Kumtor operation ...is in full compliance with all environmental, safety legislation and
regulations of the Kyrgyz Republic and that there has been no ... exceedence of any
Kyrgyz, Saskatchewan or World Bank environmental standard, nor violation of Kyrgzy regulation...
KOC is required to update its Conceptual Closure Plan (CCP) every three years. This approach allows
for the development and adaptation of the CCP, provides a period for testing and monitoring of several years to evaluate the various options contemplated by the CCP,
and is followed by the development of a Final Closure Plan (FCP) closer to the end of mine life
that will consider the results of the testing and monitoring as well as any changes to the
environmental, regulatory and social environment that may have occurred over the life of the mine.
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Strathcona Mineral Services Limited
Under the Concession Agreement, all immovable infrastructure will become the property of the
Government of the Kyrgyz Republic at the end of the mine life. This includes roads,
buildings, mill, accommodations and any other related facilities but not the operating
machinery.
A decommissioning plan was developed as required by the KOC EMAP and by the Agency Lenders,
in accordance with generally accepted environmental practices and applicable regulatory
requirements, including World Bank guidelines and the laws and regulations of the Kyrgyz
Republic, Canada and Saskatchewan. The decommissioning plan covers all aspects of the mining
project including the open pit (which will become a lake), mill complex and surrounding
area, tailings basin, stockpiles and other surface facilities. Equipment, building and other
structures will be salvaged to the extent possible.
The 1999 version of the CCP was described in the prospectus issued on occasion of the
Centerra IPO, with the future decommissioning and reclamation costs estimated at $20.4
million. In 2004, a new draft CCP was developed (Lorax Environmental, 2004) for review by
Centerra, and translated and submitted to the Kyrgyz authorities in 2005 for their
information. The Lorax plan is more detailed and is technically different from the previous
version. It uses a hydraulically placed waste rock cover, 1.5 metres thick, for the tailings
to prevent evaporation, deals in detail with future pit chemistry and water management,
including shortcomings in the current data base, and abandons the idea of high-altitude
re-vegetation in favour of contouring with glacier till material. The Lorax report describes
the scientific knowledge available at the end of 2003. The data presented indicate that the
acid rock drainage (ARD) potential of both waste dumps and tailings is very low, but that
sulphate released from the waste dumps may present a long-term concern. The report makes
recommendations for further data collection and monitoring of the various aspects important
for the closure plan such as ice movement under the load of the waste dumps, water flow and
quality into the Kumtor pit, and re-engineering of the waste dumps to limit their
interchange with meteoric water in an effort to minimize sulphate discharge particular in
the Davidov drainage as a result of sulphide oxidation.
The Lorax plan provides a total closure cost estimate of $21 million, which is close
to the 1999 closure plan. The major cost item is the tailings cover and spillway for the
tailings dam. Since the Lorax plan developed in 2004 recognizes that the waste rock dumps
will provide neutral drainage, the increased LOM plan will not produce a significant
increase in the closure cost.
The original 1999 Closure Plan anticipated that the salvage value from the sale of plant
machinery and equipment and other moveable assets would be applied against final reclamation
costs. A trust fund was established for the future costs of
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Strathcona Mineral Services Limited
reclamation, net of estimated salvage value of $15 million. Funding is by contributions over
the mine life based on ounces of gold sold. On December 31, 2005, the balance in the fund
was $4.4 million. The current trend in the mining industry with projects comparable to
Kumtor is to assume a zero salvage value. However, Centerra continues to anticipate that a
salvage value will develop, especially with the new mining equipment purchased in the next
two to three years, and that the salvage value, together with the proceeds of the
reclamation trust fund, will be sufficient to cover all decommissioning and reclamation
costs.
|
17.11 |
|
Occupational Health and Safety |
Safety elements were incorporated in the design and operational procedures of the mine. The
open-pit operation is carried out under safe blasting procedures. Slopes are designed with a
1.3 failure factor and stability is constantly monitored for safety as well as for optimum
design. Pit design has incorporated rock fall catchment berms and an updated wall monitoring system as described in Section 15.8. The haul road is
constructed 25 metres wide to allow two haul trucks to pass safely with proper safety berms
and drainage ditches. Waste is stockpiled over ice, and waste pile height is restricted to
90 metres to avoid slope instability. Dumping berms and procedures are in place to avoid
incidents with equipment. A monitoring program is in place to ensure that waste pile
deformations due to shifting ground or weather conditions, are properly addressed. Pit
operators are properly trained in the safe handling of heavy equipment.
Process and effluent treatment facilities were designed to address issues of dust control,
noise, toxic chemicals, moving pieces of stationary equipment, potential electrical and fire
hazards.
The camp complex, providing accommodation, kitchen, dining and recreation facilities, is
equipped with heat and smoke detectors, an integrated sprinkler system and hand-held fire hoses and extinguishers.
The transportation of materials and personnel, both on- and off-site, is undertaken under
specific accident prevention and safety procedures that include speed limitations and
control signs as required. All vehicles and personnel buses are equipped with two-way radios
for emergencies. All transport equipment units are under a preventive maintenance program.
The mine site is under security with authorized entry policy enforced by specialized
personnel.
At the mine site, one doctor and one certified nurse provide first aid, routine medical
services and operate a fully equipped first-aid clinic centre. An industrial hygiene
monitoring program is conducted with analysis of samples contracted to an independent
laboratory. Two ambulances, each equipped to accommodate a
88
Strathcona Mineral Services Limited
stretcher and containing appropriate medical supplies, are on standby at the mill building.
Emergency medivac from the mine site is available as necessary.
All KOC and contractor employees are trained in the use of the Five Point Safety System and
the Work Place Hazardous Information System before commencing work at the site. First aid,
mine rescue and fire fighting training is provided at the site on a regular schedule which
accounts for approximately 70 000 man-hours of new employee and refresher training per year.
Full mine rescue and fire fighting teams are always available on site with current
qualifications and training to address any emergency. The site is equipped with a fire
truck. Hydrants were installed strategically throughout the major facility areas. Fire
fighting equipment is stored at convenient locations, ready for use.
Kumtors Safety Program has been audited internally by Cameco on an annual basis and through
two external reviews since 1999. The last external detailed review of the safety program
occurred in 2001 by Golder Associates during the development of the formal Health and Safety
Management System. Prior to this, James Pirie & Associates conducted an independent audit of
KOCs safety program and workplace conditions in 1999 and concluded that KOCs occupational
health and safety practices comply with sound international mining practices.
An internal Hazardous Identification, Risk Assessment, and Control review was carried out in
2001 with all KOC facilities and departments, resulting in a number of corrective actions
being performed. The results of a review in 2005 form the basis of departmental safety
action plans through 2006 and 2007
All action plans with both safety and environmental initiatives are tracked through KOCs
Corrective & Prevention Action Ledger system and are reviewed at site in morning meetings
and on a monthly basis.
Lost-time injuries have occurred at a rate of 2 to 8 in each of the years 1997 to 2003, with
one fatality in each of 1997, 1999, 2000 and 2002. The last such fatality occurred when a
foreman was buried by waste rock during the highwall ground movement in July 2002. The
lost-time accident frequency rate has declined from the range of 0.4 to 0.5 per 200 000
man-hours in 1997 through 1999 to a level of 0.1 to 0.3 since then. This is an excellent
record which compares favourably with large-scale open-pit operations elsewhere in the
world.
All gold doré produced by the Kumtor mine is purchased at the mine site by Kyrgyzaltyn under
the Gold and Silver Sale Agreement (including amendments) for processing at its refinery in
the Kyrgyz Republic. Under the Gold and Silver Sale
89
Strathcona Mineral Services Limited
Agreement, Kyrgyzaltyn is required to pay for all gold delivered to it based on the
afternoon fixing of the price of gold on the London Bullion Market on the same business day
on which KGC provides notice that a consignment of gold is available (the Gold Sales
Notice). If Kyrgyzaltyn does not purchase all of the gold doré offered by KGC in a Gold
Sales Notice, the Investment Agreement provides that KGC may export and sell the gold
outside of the Kyrgyz Republic without restriction. All gold doré produced by the mine to
date has been purchased by Kyrgyzaltyn pursuant to these pricing mechanisms without
incident.
The Investment Agreement stabilizes all existing Kyrgyz taxation legislation in effect on
December 31, 2003. Any future taxes levied by the Government of the Kyrgyz Republic, which
differ from those stipulated in the Investment Agreement, will be a tax law change. KGC
has the right to elect whether to be subject to any such change in tax laws or regulations
that modifies the amount or timing of tax or the manner in which tax liability is determined
or calculated, or instead remain subject to the tax in effect prior to the change for a term
of 10 years from the date of the change. If a tax law change eliminates any specified tax in
its entirety, KGC will remain subject to that tax as it existed prior to its elimination.
However, if KGC elects to be subject to a tax law change that imposes an additional burden
equivalent to that imposed by the eliminated tax, then it will cease to be subject to
the eliminated tax. If a tax law change results in a reduction in the rate of any specified
tax without eliminating it, KGC will benefit from this reduction. KGC will also continue to
benefit from an exemption from certain value-added taxes, the non-application of the road
tax to hedging revenues, and a cap on the environmental protection tax.
The following is a summary of the taxes that are applied against the operations of the
Kumtor mine under the laws of the Kyrgyz Republic.
|
17.13.1 |
|
Corporate Profit Tax |
KGC and KOC are companies resident in the Kyrgyz Republic and are subject to tax on profit
at a rate of 20%.
KGC has amended the tax bases for certain assets and liabilities in compliance with the tax
legislation of the Kyrgyz Republic. Net losses carried forward from 1999, 2000 and 2002 have
fully offset profit taxes otherwise payable in 2003, 2004 and 2005. As at December 31, 2005,
KGC had $6.1 million of tax-loss carry-forwards remaining from 2002 that it intends to apply
to reduce future profit taxes otherwise payable. This remaining tax loss carry-forward will
expire in 2007. As a result, deferred tax assets of $6.1 million have been recognized in the
KGC financial statements.
90
Strathcona Mineral Services Limited
Value-added tax (VAT) is 20% on goods and services produced in, as well as goods imported
into, the Kyrgyz Republic. The Investment Agreement extends the exemption from VAT provided
to KGC and KOC under the Master Agreement on capital equipment, operating supplies, raw
materials and management fees paid by KGC to KOC.
There is a road tax of 0.8% of gross revenue (excluding gains and losses under hedging
agreements), and an emergency fund tax of 1.5% and a mineral resource deduction tax of 5%
are levied on the value of products sold.
Under the Concession Agreement, KGC is obligated to pay a concession payment of $4 per troy
ounce of gold sold. These payments are to be made quarterly within 90 days of the end of
each calendar quarter based on gold sales that quarter by KGC.
KGC is obligated to pay 2% of its net profits into a social development fund for the benefit
of the residents of the Issyk-Kul area until its senior, subordinated and shareholder loans
are repaid in full, and thereafter, 4% of its net profits.
There is a 10% withholding tax on dividends and interest by KGC paid to nonresidents,
excluding interest paid on account of the inter-company loans described in
Section 17.16. There is a 30% withholding tax on services provided by non-resident companies
for services provided within the Kyrgyz Republic and a 5% withholding tax on insurance.
Other taxes payable by KGC, including excise tax, payroll tax, environmental protection tax,
customs fees and duties, withholding taxes on insurance contracts and non-resident services,
and local taxes are expected to average about $2.4 million per year of which about 75% would
be for customs fees and duties.
|
17.14 |
|
Historical Operating Cost Performance |
The Kumtor operation has had a good history of improving operating costs, which have,
however, increased in the past two years, an experience shared by many other mining
operations as the result of increases in energy and material costs. The
following Table 19 presents an update of data that were already included in our 2004 report.
91
Strathcona Mineral Services Limited
Table
19 Historical Operating Costs, 1997 2005
thousands of tonnes, ounces and dollars, except unit figures
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1997 |
| |
| 1998 |
| |
| 1999 |
| |
| 2000 |
| |
| 2001 |
| |
| 2002 |
| |
| 2003 |
| |
| 2004 |
| |
| 2005 |
|
| |
Total |
|
|
|
|
|
|
|
|
Production
|
Mining Ore & Waste |
|
tonnes |
|
|
|
22 900 |
|
|
|
31 900 |
|
|
|
41 200 |
|
|
|
43 300 |
|
|
|
52 500 |
|
|
|
54 300 |
|
|
|
77 700 |
|
|
|
84 855 |
|
|
|
81 038 |
|
|
|
|
489 693 |
|
Milling |
|
tonnes |
|
|
|
4 023 |
|
|
|
5 254 |
|
|
|
5 298 |
|
|
|
5 498 |
|
|
|
5 470 |
|
|
|
5 611 |
|
|
|
5 631 |
|
|
|
5 654 |
|
|
|
5 649 |
|
|
|
|
48 088 |
|
Gold Produced (Table 12) |
|
ounces |
|
|
|
502 |
|
|
|
645 |
|
|
|
610 |
|
|
|
670 |
|
|
|
753 |
|
|
|
529 |
|
|
|
678 |
|
|
|
657 |
|
|
|
501 |
|
|
|
|
5 546 |
|
|
|
|
|
|
|
|
Operating Costs
|
|
|
|
|
|
|
|
Mining |
|
|
|
|
|
|
|
21 200 |
|
|
|
25 700 |
|
|
|
27 900 |
|
|
|
26 000 |
|
|
|
28 900 |
|
|
|
33 600 |
|
|
|
37 500 |
|
|
|
40 508 |
|
|
|
47 804 |
|
|
|
|
289 113 |
|
Milling |
|
|
|
|
|
|
|
26 300 |
|
|
|
33 600 |
|
|
|
29 000 |
|
|
|
29 300 |
|
|
|
30 900 |
|
|
|
29 000 |
|
|
|
28 900 |
|
|
|
30 585 |
|
|
|
32 346 |
|
|
|
|
269 931 |
|
Site & Bishkek Administration |
|
|
|
|
|
|
|
41 600 |
|
|
|
44 500 |
|
|
|
36 800 |
|
|
|
35 600 |
|
|
|
33 300 |
|
|
|
31 300 |
|
|
|
34 500 |
|
|
|
35 743 |
|
|
|
35 611 |
|
|
|
|
328 954 |
|
Production & Revenue Taxes |
|
|
|
|
|
|
|
3 300 |
|
|
|
5 100 |
|
|
|
7 400 |
|
|
|
5 200 |
|
|
|
5 600 |
|
|
|
11 200 |
|
|
|
24 900 |
|
|
|
21 146 |
|
|
|
17 883 |
|
|
|
|
101 729 |
|
Management Fees & Others |
|
|
|
|
|
|
|
4 100 |
|
|
|
7 800 |
|
|
|
8 100 |
|
|
|
6 300 |
|
|
|
7 800 |
|
|
|
9 300 |
|
|
|
9 100 |
|
|
|
3 424 |
|
|
|
3 515 |
|
|
|
|
59 439 |
|
|
|
|
|
|
|
|
Totals |
|
|
|
|
|
|
|
96 500 |
|
|
|
116 700 |
|
|
|
109 200 |
|
|
|
102 400 |
|
|
|
106 500 |
|
|
|
114 400 |
|
|
|
134 900 |
|
|
|
131 406 |
|
|
|
137 160 |
|
|
|
|
1 049 166 |
|
|
|
|
|
|
|
|
Unit Operating Costs
|
|
|
|
|
|
|
|
Mining |
|
|
|
|
|
|
|
0.93 |
|
|
|
0.81 |
|
|
|
0.68 |
|
|
|
0.60 |
|
|
|
0.55 |
|
|
|
0.62 |
|
|
|
0.48 |
|
|
|
0.48 |
|
|
|
0.59 |
|
|
|
|
0.59 |
|
Milling |
|
|
|
|
|
|
|
6.54 |
|
|
|
6.40 |
|
|
|
5.47 |
|
|
|
5.33 |
|
|
|
5.65 |
|
|
|
5.17 |
|
|
|
5.13 |
|
|
|
5.41 |
|
|
|
5.73 |
|
|
|
|
5.61 |
|
Total per Tonne Milled |
|
|
|
|
|
|
|
23.99 |
|
|
|
22.21 |
|
|
|
20.61 |
|
|
|
18.63 |
|
|
|
19.47 |
|
|
|
20.39 |
|
|
|
23.96 |
|
|
|
23.24 |
|
|
|
24.28 |
|
|
|
|
21.82 |
|
Cash Cost per Ounce of Gold
Produced |
|
|
|
|
|
|
|
192 |
|
|
|
181 |
|
|
|
179 |
|
|
|
153 |
|
|
|
141 |
|
|
|
216 |
|
|
|
199 |
|
|
|
200 |
|
|
|
274 |
|
|
|
|
189 |
|
|
|
|
|
|
|
|
Others includes VAT and excise taxes, and customs duties. Starting in 2004, operating costs are
net of by-product revenues and include refining fees, but
exclude management fees paid to KOC when KOC became a subsidiary of the newly created
Centerra.
92
Strathcona Mineral Services Limited
17.15 Capital and Operating Cost Estimates
Based on the operating cost experience to date, and anticipating the additional haulage costs
associated with the deepening Kumtor pit and with the more distant Southwest deposit pit,
the LOM plan projects operating costs that are summarized in Table 20. Unit operating costs per
tonne milled vary from $13 per tonne range in the last two years of the LOM plan when only
stockpiled material is being milled, to $32 per tonne in 2009, when stripping requirements are
still high and production and revenue taxes are at a peak. The cost per ounce of gold produced
varies depending on the mill head grade in addition to operating conditions and averages $256 per
ounce of gold for the period 2006-2013.
The projected unit operating costs are in line with those experienced in the past two years, but
the total cost per tonne milled increases because of the additional waste being mined in the years
2006 to 2010. The cash operating costs of $260 per ounce are higher
than the historical average of $191 per ounce for the same reason along with an overall lower mill
head grade delivered from the pits, and the inclusion of much of the remaining low-grade stockpiles
in the LOM plan.
The capital cost forecast in the LOM plan is summarized in Table 21. Total capital costs amount to
$132 million, of which $110 million are mine capital items and $13 million are for the tailings
dam. Exploration expenditures (approved for 2006 in the amount of $11.4 million) are not included
in this list.
17.16 Financing
As of December 31, 2005 KGC had two loans outstanding of $10 million each, remaining from the
original senior and subordinated debt financing arranged for the development of the Kumtor project
but now treated as an inter-company debt with Centerra. The inter-company repayment program allows
for a semi-annual payment of $2.5 million against each of the two loans. The next payment is
scheduled for December, 2006, and full repayment, including accrued interest, is to be completed by
June, 2008. Interest payable during the time of debt retirement is $6.5 million. A further loan
from a Cameco subsidiary that was transferred to Centerra has been fully repaid, including accrued
interest, on December 2, 2005. All of the remaining debt with external lenders involved in the
original Kumtor project financing has either been repaid or converted to equity as part of the
initial public offering of shares by Centerra. An amount of $1.5 million per annum for risk
insurance of is included in the financing costs in Table 22.
93
Strathcona Mineral Services Limited
Table
20 Projected Operating Costs, 2006 2013
thousands of tonnes, ounces and dollars, except unit figures
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2006 |
|
2007 |
|
2008 |
|
2009 |
|
2010 |
|
2011 |
|
2012 |
|
2013 |
|
|
Total |
|
|
|
|
|
|
|
|
Production
|
|
|
|
|
|
|
|
Mining Ore & Waste |
|
tonnes |
|
|
|
101 367 |
|
|
|
131 575 |
|
|
|
112 431 |
|
|
|
118 440 |
|
|
|
123 276 |
|
|
|
100 971 |
|
|
|
|
|
|
|
|
|
|
|
|
688 060 |
|
Milling (Table 12) |
|
tonnes |
|
|
|
5 659 |
|
|
|
5 658 |
|
|
|
5 658 |
|
|
|
5 658 |
|
|
|
5 658 |
|
|
|
5 658 |
|
|
|
5 657 |
|
|
|
894 |
|
|
|
|
40 500 |
|
Gold Produced |
|
ounces |
|
|
|
461 |
|
|
|
533 |
|
|
|
673 |
|
|
|
843 |
|
|
|
764 |
|
|
|
627 |
|
|
|
206 |
|
|
|
37 |
|
|
|
|
4 144 |
|
|
|
|
|
|
|
|
Projected Operating Costs
|
|
|
|
|
|
|
|
Mining |
|
|
|
|
|
|
|
63 747 |
|
|
|
80 034 |
|
|
|
80 632 |
|
|
|
80 776 |
|
|
|
64 876 |
|
|
|
46 677 |
|
|
|
7 407 |
|
|
|
|
|
|
|
|
424 149 |
|
Milling |
|
|
|
|
|
|
|
37 466 |
|
|
|
34 995 |
|
|
|
35 082 |
|
|
|
33 904 |
|
|
|
34 104 |
|
|
|
33 033 |
|
|
|
32 367 |
|
|
|
5 118 |
|
|
|
|
246 069 |
|
Site & Bishkek Administration |
|
|
|
|
|
|
|
38 448 |
|
|
|
35 064 |
|
|
|
32 364 |
|
|
|
31 694 |
|
|
|
31 516 |
|
|
|
29 548 |
|
|
|
27 898 |
|
|
|
4 411 |
|
|
|
|
230 943 |
|
Production & Revenue Taxes |
|
|
|
|
|
|
|
15 936 |
|
|
|
17 695 |
|
|
|
22 343 |
|
|
|
27 988 |
|
|
|
25 365 |
|
|
|
20 816 |
|
|
|
6 839 |
|
|
|
1 545 |
|
|
|
|
138 527 |
|
Management Fees & Others |
|
|
|
|
|
|
|
3 647 |
|
|
|
4 412 |
|
|
|
4 612 |
|
|
|
4 857 |
|
|
|
4 188 |
|
|
|
3 312 |
|
|
|
1 311 |
|
|
|
232 |
|
|
|
|
26 571 |
|
|
|
|
|
|
|
|
Totals |
|
|
|
|
|
|
|
159 244 |
|
|
| 172 200 |
|
|
| 175 033 |
|
|
| 179 219 |
|
|
| 160 049 |
|
|
| 133 386 |
|
|
| 75 822 |
|
|
| 11 306 |
|
|
|
| 1 066 259 |
|
|
|
|
|
|
|
|
Unit Operating Costs
|
|
|
|
|
|
|
|
Mining |
|
|
|
|
|
|
|
0.63 |
|
|
|
0.61 |
|
|
|
0.72 |
|
|
|
0.68 |
|
|
|
0.53 |
|
|
|
0.46 |
|
|
|
|
|
|
|
|
|
|
|
|
0.62 |
|
Milling |
|
|
|
|
|
|
|
6.62 |
|
|
|
6.19 |
|
|
|
6.20 |
|
|
|
5.99 |
|
|
|
6.03 |
|
|
|
5.84 |
|
|
|
5.72 |
|
|
|
5.72 |
|
|
|
|
6.08 |
|
Per tonne milled |
|
|
|
|
|
|
|
28.14 |
|
|
|
30.43 |
|
|
|
30.94 |
|
|
|
31.68 |
|
|
|
28.29 |
|
|
|
23.57 |
|
|
|
13.40 |
|
|
|
12.65 |
|
|
|
|
26.33 |
|
Cash Cost per ounce produced |
|
|
|
|
|
|
|
347 |
|
|
|
325 |
|
|
|
262 |
|
|
|
214 |
|
|
|
211 |
|
|
|
214 |
|
|
|
369 |
|
|
|
306 |
|
|
|
|
256 |
|
|
|
|
|
|
|
|
Others includes VAT and excise taxes, and customs duties
Cash Cost per ounce produced includes allowances for refining fees and silver by-product revenue
94
Strathcona Mineral Services Limited
Table
21 Projected Capital Costs, 2006 2013
thousands of dollars
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2006 |
|
2007 |
|
2008 |
|
2009 |
|
2010 |
|
2011 |
|
2012 |
|
2013 |
|
|
Total |
|
|
Mine |
|
|
82 666 |
|
|
|
19 434 |
|
|
|
5 331 |
|
|
|
1 906 |
|
|
|
531 |
|
|
|
208 |
|
|
|
86 |
|
|
|
|
|
|
|
110 162 |
|
Tailings Dam |
|
|
3 244 |
|
|
|
2 724 |
|
|
|
3 033 |
|
|
|
2 310 |
|
|
|
1 212 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
12 523 |
|
Others |
|
|
7 970 |
|
|
|
1 836 |
|
|
|
|
|
|
|
62 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
9 868 |
|
|
Total |
|
|
93 880 |
|
|
|
23 994 |
|
|
|
8 364 |
|
|
|
4 278 |
|
|
|
1 743 |
|
|
|
208 |
|
|
|
86 |
|
|
|
0 |
|
|
|
132 553 |
|
|
Others includes capital expenditures for the mill, a new maintenance workshop and office
supplies.
95
Strathcona Mineral Services Limited
Table
22 Projected Mine Net Cash Flow, 2006 2013
thousands of ounces and dollars
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2006 |
|
2007 |
|
2008 |
|
2009 |
|
2010 |
|
2011 |
|
2012 |
|
2013 |
|
|
Total |
|
|
|
|
|
|
|
|
Sales Revenue
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Gold Sold (*) |
|
ounces |
|
|
|
480 |
|
|
|
533 |
|
|
|
673 |
|
|
|
843 |
|
|
|
764 |
|
|
|
627 |
|
|
|
206 |
|
|
|
47 |
|
|
|
|
4 173 |
|
Gold Price |
|
$/ounce |
|
|
|
400 |
|
|
|
400 |
|
|
|
400 |
|
|
|
400 |
|
|
|
400 |
|
|
|
400 |
|
|
|
400 |
|
|
|
400 |
|
|
|
|
|
|
Revenue from Gold |
|
|
|
|
|
|
|
192 000 |
|
|
|
213 200 |
|
|
|
269 200 |
|
|
|
337 200 |
|
|
|
305 600 |
|
|
|
250 800 |
|
|
|
82 400 |
|
|
|
18 611 |
|
|
|
|
1 669 011 |
|
Refining Fee |
|
|
|
|
|
|
|
(2 015 |
) |
|
|
(2 244 |
) |
|
|
(2 850 |
) |
|
|
(3 585 |
) |
|
|
(3 794 |
) |
|
|
(3 103 |
) |
|
|
(999 |
) |
|
|
(226 |
) |
|
|
|
(18 816 |
) |
Silver Credit |
|
|
|
|
|
|
|
1 139 |
|
|
|
1 265 |
|
|
|
1 597 |
|
|
|
2 001 |
|
|
|
2 899 |
|
|
|
2 379 |
|
|
|
782 |
|
|
|
177 |
|
|
|
|
12 239 |
|
|
|
|
|
|
|
|
Net Revenues |
|
|
|
|
|
|
|
191 124 |
|
|
|
212 221 |
|
|
|
267 947 |
|
|
|
335 616 |
|
|
|
304 705 |
|
|
|
250 076 |
|
|
|
82 183 |
|
|
|
18 562 |
|
|
|
|
1 662 434 |
|
|
|
|
|
|
|
|
Cash Outflows
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Operating Costs (Table 20) |
|
|
|
|
|
|
|
159 244 |
|
|
|
172 200 |
|
|
|
175 033 |
|
|
|
179 219 |
|
|
|
160 049 |
|
|
|
133 386 |
|
|
|
75 822 |
|
|
|
11 306 |
|
|
|
|
1 066 259 |
|
Debt Repayment and Financing |
|
|
|
|
|
|
|
9 800 |
|
|
|
13 875 |
|
|
|
7 325 |
|
|
|
1 500 |
|
|
|
1 500 |
|
|
|
1 500 |
|
|
|
1 500 |
|
|
|
250 |
|
|
|
|
37 250 |
|
Capital Costs (Table 21) |
|
|
|
|
|
|
|
93 880 |
|
|
|
23 994 |
|
|
|
8 364 |
|
|
|
4 278 |
|
|
|
1 743 |
|
|
|
208 |
|
|
|
86 |
|
|
|
|
|
|
|
|
132 553 |
|
Working Capital |
|
|
|
|
|
|
|
3 000 |
|
|
|
6 000 |
|
|
|
1 000 |
|
|
|
(2 000 |
) |
|
|
(2 000 |
) |
|
|
(2 000 |
) |
|
|
(4 000 |
) |
|
|
|
|
|
|
|
0 |
|
|
|
|
|
|
|
|
Total Cash Outflow |
|
|
|
|
|
|
|
265 924 |
|
|
|
216 069 |
|
|
|
191 722 |
|
|
|
182 997 |
|
|
|
161 292 |
|
|
|
133 094 |
|
|
|
73 408 |
|
|
|
11 556 |
|
|
|
|
1 236 062 |
|
|
|
|
|
|
|
|
Profit Taxes |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
17 410 |
|
|
|
25 140 |
|
|
|
20 533 |
|
|
|
|
|
|
|
|
|
|
|
|
63 083 |
|
|
|
|
|
|
|
|
Net Cash Flow |
|
|
|
|
|
|
|
(74 800 |
) |
|
|
(3 848 |
) |
|
|
76 225 |
|
|
|
135 209 |
|
|
|
118 273 |
|
|
|
96 449 |
|
|
|
8 775 |
|
|
|
7 006 |
|
|
|
|
363 289 |
|
Cumulative |
|
|
|
|
|
|
|
(74 800 |
) |
|
|
(78 648 |
) |
|
|
(2 423 |
) |
|
|
132 786 |
|
|
|
251 059 |
|
|
|
347 508 |
|
|
|
356 283 |
|
|
|
363 289 |
|
|
|
|
|
|
|
|
|
|
|
|
|
Net Present Value at 10% |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
224 455 |
|
|
|
|
|
|
|
|
|
|
|
(*) |
|
Gold sold includes gold in inventory and is therefore slightly more than the gold produced
shown in Table 20. |
96
Strathcona Mineral Services Limited
17.17 Economic Analysis
Using a gold price of $400 per ounce, the LOM plan projects the cash flow for the
Kumtor operation for the years 2006 - 2013 summarized in Table 22, and which totals $363
million, net of capital expenditures, financing costs and taxes. As discussed in
Section 15.13, the LOM plan is based on proven and probable reserves only. Exploration
expenditures, set at a minimum of $11.4 million for 2006 and probably continuing at that
level for another two or three years, are not included in the cash
flow in Table 22.
At a gold price of $400 per ounce and including capital expenditures, the operation will be
cash-flow negative in 2006, slightly cash-flow positive in 2007 and will be highly cash-flow
positive in the ensuing years. The capital expenditures for 2006 and 2007 in the amount of
$118 million represent 89% of the total currently anticipated capital costs at Kumtor, and
are fully repaid in 2009.
Centerra have provided cash flow forecasts for the Kumtor mine for the period 2006-2013
based on the current LOM plan, and at gold prices from $400 to $600 per ounce. The net
present values (NPV) of those cash flows at discount rates of 0%,
5% and 10% are tabulated in Table 23 and shown graphically in Figure 17.
A gold price of close to $300 per ounce is required to achieve neutral cash flow over the
presently foreseen life of the mine while meeting all anticipated requirements for
operations, capital expenditures, debt repayment, taxes and reclamation costs, but excluding
exploration expenditures. At higher gold prices, such as the current level of about $550 per
ounce, the Kumtor mine will have the potential to generate substantial cash flow.
Other than the gold price, the only other parameter that would have the possibility of
having a significant impact on mine cash flow would be an increase in operating costs, with
a 10% increase reducing cumulative cash flow over the period of the LOM plan by about $90
million at a constant gold price of $400 per ounce. Any changes in the gold grade of ore
mined in the period of the LOM plan are likely to be minimal given the good history of
reconciliation between reserve grades and the
grade of material processed in the plant, and thus the Kumtor projected cash flow is not
considered to be particularly at risk from changes in reserve grade, given good grade
control practices.
97
Strathcona Mineral Services Limited
Table
23 NPV of Mine Net Cash Flow 2006 2013
Millions of dollars
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Discount Rate |
|
|
|
|
|
|
0% |
|
5% |
|
10% |
|
|
|
|
Sensitivity to Gold Price
|
|
|
|
|
Gold Price |
|
|
300 |
|
|
|
|
52 |
|
|
|
19 |
|
|
|
(6 |
) |
($/ounce) |
|
|
400 |
|
|
|
|
363 |
|
|
|
285 |
|
|
|
225 |
|
|
|
|
500 |
|
|
|
|
674 |
|
|
|
550 |
|
|
|
455 |
|
|
|
|
600 |
|
|
|
|
980 |
|
|
|
810 |
|
|
|
679 |
|
|
|
|
|
10% Decrease in Operating Costs
|
|
|
|
|
Gold Price |
|
|
300 |
|
|
|
|
138 |
|
|
|
93 |
|
|
|
60 |
|
($/ounce) |
|
|
400 |
|
|
|
|
450 |
|
|
|
359 |
|
|
|
290 |
|
|
|
|
500 |
|
|
|
|
762 |
|
|
|
625 |
|
|
|
520 |
|
|
|
|
600 |
|
|
|
|
1 070 |
|
|
|
887 |
|
|
|
742 |
|
|
|
|
|
10% Increase in Operating Costs
|
|
|
|
|
Gold Price |
|
|
300 |
|
|
|
|
(30 |
) |
|
|
(52 |
) |
|
|
(69 |
) |
($/ounce) |
|
|
400 |
|
|
|
|
277 |
|
|
|
210 |
|
|
|
159 |
|
|
|
|
500 |
|
|
|
|
583 |
|
|
|
472 |
|
|
|
386 |
|
|
|
|
600 |
|
|
|
|
890 |
|
|
|
733 |
|
|
|
612 |
|
|
|
|
|
Note: The lower part of Figure 17 shows the case for a gold price of $400 per ounce.
98
Strathcona Mineral Services Limited
Figure 17 Cash Flow Sensitivities
99
Strathcona Mineral Services Limited
18. INTERPRETATION AND CONCLUSIONS
Our review of the Kumtor project has confirmed that the performance of the Kumtor mine
in achieving production in accordance with projections based on mineral reserve estimates to
date has been very good. The exception has been the
second half of 2005 when the KS-5 reserve model did not fully account for external dilution
in the thinner and less continuous parts of the deposit. The new KS-6 model, on which the
December 31, 2005 mineral reserves for the Kumtor operation are based, addresses this
concern in a satisfactory manner.
To the end of 2005, the Kumtor mine has recorded an average mill head gold grade
of 4.5 g/t (Table 4), which was based on the high-grade Stockwork Zone in the northern part
of the pit that is now largely mined. The year-end 2004 reserves projected a still
profitable but lower-grade future with mineral reserves of 28.2 million tonnes with an
average grade of 3.3 g/t gold.
As a result of a systematic and substantial surface exploration program, a partial
replacement for the Stockwork Zone has now been found in the southern part of the deposit in
the form of the SB Zone, that has led to a reserve increase in 2005 of nearly 15 million
tonnes. The net increase in the reserves at year-end 2005 versus 2004 is about 9.0 million
tonnes after processing 5.6 million tonnes in 2005. The increase allows an extension of the
mine life from mid-2010 to mid-2013, and the gold grade of the new reserves at 3.9 g/t
starts to approach the historical production grade.
Since the centre of the SB Zone is at some depth below surface, and is also covered with
waste dumps, pre-stripping is required in the southern part of the Kumtor pit, the footprint
of which is much larger compared to a year earlier. Total tonnage mined in the next few
years will be up to 50% higher than previously in order to achieve the stripping
requirements. The increase in waste production capacity requires a capital expenditure of
more than $100 million for mining equipment in 2006 and 2007. The
capital expenditures are repaid rapidly within the following two years (Table 22), assuming
a gold price of $400 per ounce.
Exploration expenditures for 2006 are budgeted at $11.4 million, mostly for surface
drilling, to identify new mineral resources. Centerra has made a strong commitment to fund a
continued exploration program to extend the life of the Kumtor operation with a good
possibility of success.
100
Strathcona Mineral Services Limited
As a consequence of our lengthy association with the Kumtor project, and the resultant
familiarity with its personnel, and the policies and standards followed in the management
and conduct of mining operations, our independent review of the procedures for the
estimation of the December 31, 2005 mineral resources and reserves, and the very good
production and cost performance during the nine years
the mine has been in operation, we are of the opinion that the Kumtor mine should be able to
substantially achieve the production, cost and economic performance targets for the current
mine plan with the possibility of extending the mine life as a result of the commitment to
further exploration in the Kumtor area.
19. RECOMMENDATIONS
The Kumtor mine has had a very good operating history and currently has no serious
challenges except, like all mines, to replace its mineral reserves every year. Given the
success rate of previous exploration programs at Kumtor, both on the Concession Area and on
the surrounding Exploration Licence, and given the
remaining exploration possibilities discussed in Section 16, we therefore fully support the
ongoing exploration efforts that utilize the full compliment of available drilling equipment
and that has a financial commitment of $11.4 million for 2006. Further exploration
expenditures will be required in the next few years after 2006, probably at a similar level,
but details of these, and their justification, are contingent on the results of the ongoing
2006 program.
The results of the surface exploration drilling completed in the past two years has now filled in
the hitherto missing information in the lower part of the deposit. There has been a long-standing
open question as to what to do with the substantial additional resources that have been identified
at Kumtor but that could not be included in mineral reserves because of the very large associated
incremental strip ratio. This has been a dynamic process, with the additional drilling (and the
recent increase in the price of gold), allowing a gradual deepening of the final design pit, with
the exploration results adding new reserves and resources below or beyond that pit, particularly
in the SB and NB Zones.
Apart from an outdated study in 1999, the question of underground mining at Kumtor has not been
perceived as an urgent issue. With the additional deep information now available, Centerra plans to
conduct studies into the technical and economic aspects of possible underground mining, and to
include in those studies those additional mineral resources that are currently reported at the
open-pit cut-off gold grade. Such studies will determine more definitely the cut-off grade at which
possible underground resources should be reported, and indicate the cross-over point
101
Strathcona Mineral Services Limited
between open-pit and underground mining. Time is of the essence for this undertaking, since
underground mining needs to be concurrent with open-pit mining, given the large capacity of
the gold recovery plant.
If additional ore can be found in the Northend area of the Kumtor deposit as noted
in Section 16.1, raising the possibility of expanding the pit, the existence of the
underground scoping study will allow a quicker and more accurate appraisal of where the
future pit bottom should be than is currently possible.
102
Strathcona Mineral Services Limited
20. REFERENCES
BGC Engineering Inc., 2005a
Kumtor Mine Tailings Verification Assessment and Technical Review. Unpublished report for
Centerra Gold Inc. dated September 23, 2005
BGC Engineering Inc., 2005b
Kumtor
Tailings Dam Design of Shear Key Extension. Unpublished letter report dated December 22,
2005
Cameco Corporation, 1999
Kumtor Underground Project. Preliminary Evaluation. September 1999
Canadian Institute of Mining, Metallurgy and Petroleum, 2005
CIM Definitions and Standards on Mineral Resources and Mineral Reserves (adopted by CIM Council
December 11, 2005).
Chukin, B. A., 2005
Informal letter report on the Davidov glacier and its effect on waste dumps and the southwestern
part of the Kumtor pit dated September 30, 2005
Cole, A., 1992:
Gold Mineralisation in the Southern Tien Shan, Central Asia: Tectonic Setting, Characteristics and
Regional Exploration Criteria. International Geology Review, 34, 1992, 88-94.
Diatchkov, S.A., 1994
Principles of Classification of Reserves and Resources in the CIS Countries. Mining Engineering,
March 1994, 214-217
Golder Associates Ltd., 2002a
Kumtor
Project Southwest Zone. Preliminary Slope Design
Recommendations Draft. Unpublished
letter report dated May 10, 2002.
103
Strathcona Mineral Services Limited
Golder Associates Ltd., 2002b
Slope Designs for the Northeast Wall of the OCT2002MDP Mine Plan. Unpublished letter report
dated November 7, 2002 with attached Technical Memorandum (Northeast Wall Stability
Analyses) dated September 17, 2002.
Golder Associates Ltd., 2005
Preliminary Assessment of Davydov Glacier Impacts on Proposed Southwest Pushback. Draft
letter report dated December 9, 2005.
Ivanov, S. M., Ansdell, K. M. & Melrose, D. L., 2000
Ore Texture and Stable Isotope Constraints on Ore Deposition Mechanisms at the Kumtor Lode
Gold Deposit. In: Bucci, L.A. and Mair, J.L. (eds), Gold in 2000. Poster session extended
abstracts, p.47-52. Downloaded from website http://homepage.usask.ca/~smi454/project/
articles/golkd2000_ext_abs.htm
Ivanov, S. M. and Ansdell, K. M., 2002
Mineralization Styles and Fluid Evolution at the Kumtor Gold Deposit, Kyrgyz Republic:
Textures, Stable Isotopes and Fluid Inclusions. Geol. Ass. Can. Annual Meeting, Saskatoon
2002, Abstracts.
Kentor Gold Ltd., 2005
Managing Directors Address to AGM, November 24, 2005. Slide show accessible at the Kentor
website (www.kentorgold.com/admin/upload/MD%20Kentor_AGM _2005.pdf)
Kilborn Western Inc., 1993-1995
Kumtor Gold Project Feasibility Study for Kumtor Gold Company. Unpublished document dated
November 1993, updated April 1994 and May 1995
Kumtor Operating Company
Monthly Production Reports from December 1996 to December 2005.
104
Strathcona Mineral Services Limited
Kumtor Operating Company, 2002
The Results of Additional Exploration of Kumtor Deposit in 1998-2002, Containing the
Estimate of Gold Resources as of January 1, 2002. Unpublished Internal Document dated 1st
July, 2002.
Kumtor Operating Company, 2005(?)
Annual Environmental Report 2004. Unpublished Internal Document, undated
Kumtor Operating Company, 2005(?)
Kumtor Gold Project: Expansion 2005 Technical Report. Unpublished Internal Document,
undated. Contains the justification for the inclusion of the Southwest deposit into the mine
plan of the day.
Kumtor Operating Company, 2006
Summary
Report of Kumtor Lom Expansion to Mine Great South Pit & KS6
Resource. Unpublished Internal Document dated
19th January, 2006.
Lewis, A. M., 2006
Letter to Strathcona Mineral Services Limited stating that the Kumtor operation is in
compliance with all applicable regulations and laws. Dated February 13, 2006
Lorax Environmental, 2004
Kumtor
Gold Project Conceptual Closure Plan. Unpublished Draft Report dated March 2004.
Melrose, D. L., 2003
Kumtor Exploration. Draft 5 Year Strategic Plan, 2004 2008. November 2003
Melrose, D. L., 2005
Technical Report on the Underground Program 2004-05. Review of the Completed and Planned
Drill Holes and Targets. For Kumtor Gold Mine, Kyrgyz Republic. Bilingual report dated April
20, 2005.
105
Strathcona Mineral Services Limited
Oseledko, L., Undated (probably 2002)
Expert Conclusion on the Report on the Results of Additional Exploration of Kumtor Deposit
in 1998-2002, Containing the Estimate of Gold Resources as of January 1, 2002. Report to the
Kyrgyz State Committee for Resources. Undated, probably 2002.
Savtchenko, G. A. (Undated, probably 2002)
Findings of Expert Examination of the Report on Results of Additional Exploration of Kumtor
Deposit in 1998-2002, Containing the Estimate of Gold Resources as of January 1, 2002.
Report to the Kyrgyz State Committee for Resources. Undated, probably 2002.
Strathcona Mineral Services Limited, 2004
Technical Report on the Kumtor Gold Mine, Kyrgyz Republic, for Centerra Gold Inc. filed on
Sedar, dated May 13, 2004
Vdovin, V., 2005
Conclusions on the pit wall angles for the SW pit. Internal Kumtor memorandum dated July 28,
2005
106
Strathcona Mineral Services Limited
21. DATE AND SIGNATURE PAGE
This report has been prepared by Henrik Thalenhorst, P. Geo., who is a qualified person as
defined by NI-43-101.
Submitted this 9th day of March 2006.
|
|
|
(SEAL)
|
|
|
|
|
|
|
|
|
Henrik Thalenhorst, P. Geo. |
|
|
Strathcona Mineral Services Limited
CERTIFICATE
Strathcona Mineral Services Limited
CERTIFICATE OF QUALIFIED PERSON
I, Henrik
Thalenhorst, Vice President, Strathcona Mineral Services Limited,
12th Floor, 20
Toronto Street, Toronto, Ontario, M5C 2B8 do hereby certify that:
1. |
|
I graduated from the University of Munich, Germany with a
Ph.D. in Economic Geology in 1968; |
|
|
|
I am a registered member of the Association of Professional
Geoscientists of Ontario;
|
|
|
|
I have practised my profession as a geologist continuously since graduation in 1968, and with
Strathcona Mineral Services Limited since January 1986; |
|
|
|
and therefore meet the requirements of National Instrument 43-101 for designation as a
Qualified Person. |
2. |
|
I have visited the Kumtor project in Kyrgyz Republic from November 27 to December 2,
1998, and again from January 8 to 12, 2006 to review the resource and reserve estimation
process and the data on which the estimates were based; |
3. |
|
The report of Strathcona Mineral Services Limited of March 9, 2006 entitled Technical
Update Report on the Kumtor Gold Mine, Kyrgyz Republic for Centerra Gold Inc. and Cameco
Corporation was authored by me and as an independent Qualified Person, I accept
responsibility for the contents of this report. |
|
4. |
|
I am not aware of any material fact or change that has not been disclosed in the
documentation provided by Centerra Gold Inc. and which is therefore not reflected in our
technical report. |
|
5. |
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As of the date of this certificate, to the best of my knowledge, information and belief, the
technical report contains all scientific and technical information that is required to be
disclosed to make this technical report not misleading. |
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I am independent of Centerra Gold Inc. in accordance with the requirements of National
Instrument 43-101. |
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Strathcona Mineral Services Limited
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National Instrument 43-101 and Form 43-101F1 amended as of December 30, 2005
have been read and our technical report has been prepared in accordance with the
requirements specified therein. |
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Dated at Toronto, Ontario this
9th day of March, 2006 |
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(SEAL) |
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/s/ Henrik Thalenhorst |
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Henrik Thalenhorst, P. Geo. |
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