Erosion and Sediment Control Assessment Report Rev. 0 This is an uncontrolled copy if photocopied or printed from the Intranet. Copyright © 2016, SouthernSkies Environmental Ltd. All rights reserved. Page 3 of 30 CONTENTS 1. INTRODUCTION.......................................................................................................................................4 2. PROJECT DESCRIPTION........................................................................................................................4 2.1. Overview..........................................................................................................................................4 2.2. Wharekirauponga Underground Mine .............................................................................................5 2.3. Gladstone Open Pit .........................................................................................................................8 2.4. Northern Rock Stack........................................................................................................................8 2.5. Tailings Storage Facility 3................................................................................................................9 2.6. Earthworks Summary ....................................................................................................................10 3. RECEIVING ENVIRONMENTS ..............................................................................................................11 3.1. Summary of Environments ............................................................................................................11 4. STATUTORY CONSIDERATIONS.........................................................................................................13 4.1. Resource Management Act ...........................................................................................................13 4.2. Overview of National and Regional Policy Directives....................................................................14 4.2.1. National Policy Statement for Freshwater Management 2020 .........................................14 4.2.2. Waikato Regional Policy Statement..................................................................................14 4.2.3. Waikato Regional Plan......................................................................................................15 4.3. High Level Analysis of Statutory Matters.......................................................................................15 5. Assessment Methodology .......................................................................................................................15 6. Erosion and Sediment Control Principles ...............................................................................................16 6.1. Design Standard ............................................................................................................................16 6.2. Construction Water Management Objectives and Principles ........................................................16 6.3. Design of Erosion and Sediment Control Devices ........................................................................17 6.3.1. Erosion Control - Construction Staging and Sequencing .................................................17 6.3.2. Erosion Control - Clean Water Control .............................................................................17 6.3.3. Sediment Control – Sediment Retention Ponds ...............................................................18 6.3.4. Decanting Earth Bunds .....................................................................................................18 6.3.5. Silt Fences and Super Silt Fences....................................................................................18 6.3.6. Chemical Treatment..........................................................................................................18 6.3.7. Dewatering and Pumping .................................................................................................18 6.3.8. Dust Control ......................................................................................................................19 6.3.9. Streamworks .....................................................................................................................19 7. Erosion and Sediment Control Implementation ......................................................................................19 7.1. Site Specific Erosion and Sediment Control Plans........................................................................19 7.2. Pre-construction Site Meeting .......................................................................................................20 7.3. Construction of ESCs - Supervisions ............................................................................................20 7.4. As-built Certification.......................................................................................................................20 7.5. Monitoring and Maintenance .........................................................................................................20 7.6. Decommissioning ..........................................................................................................................20 8. Monitoring and Responses .....................................................................................................................20 8.1. ESC Monitoring..............................................................................................................................20 8.2. Performance Targets .....................................................................................................................21 9. Assessment of Effects ............................................................................................................................22 9.1. ESC Design ...................................................................................................................................22 9.1.1. Willows Road Site .............................................................................................................22 9.1.2. TSF3 .................................................................................................................................23 9.1.3. NRS...................................................................................................................................23 9.1.4. Gladstone Open Pit...........................................................................................................24 9.2. Estimate of Sediment Yield ...........................................................................................................24 9.3. Streamworks ..................................................................................................................................26 9.4. Monitoring and Targets..................................................................................................................26 10. Conclusion ..............................................................................................................................................27 Appendix A: Chemical Treatment Management Plan ....................................................................................28 Appendix B: Erosion and Sediment Control Monitoring Plan .........................................................................29 Appendix C: Site Specific Erosion and Sediment Control Plans ....................................................................30
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