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6.0 Chapter 6: Prevention And Mitigation (Ward Wilson)

6.1 Introduction

6.2 Objectives of Prevention and Mitigation

6.3 The ARD Prevention and Mitigation Approach

6.4 Relevance of ARD Source

6.5 Consideration of ARD Factors

6.6 ARD and Metal Leaching and Sulphate Production

6.7 Climatic and Other Factors

6.8 Phased Approach

6.9 Overview of Methods

6.9.1 Remining

6.9.2 Special Handling Methods

6.9.2.1 Incorporation in Mine Plan

6.9.2.2 Segregation

6.9.2.3 Desulphidization

6.9.2.4 Compaction and Physical Tailings Conditioning

6.9.2.5 Encapsulation and Layering

6.9.2.6 Blending

6.9.2.7 Co-disposal

6.9.2.8 Permafrost and Freezing

6.9.3 Additions and Amendment Methods

6.9.3.1 Passivation

6.9.3.2 Alkaline materials

6.9.3.3 Organics

6.9.3.4 Bactericides

6.9.4 Water Management Methods

6.9.4.1 Hydrodynamic controls

6.9.4.2 Dewatering

6.9.4.3 Diversion

6.9.4.4 Filling

6.9.4.5 Seals

6.9.5 Dry Cover Methods

6.9.5.1 Organic

6.9.5.2 Soil

6.9.5.3 Limestone and Alkaline

6.9.5.4 Synthetic

6.9.5.5 Gas

6.9.5.6 Vegetation

6.9.6 Water Cover Methods

6.9.6.1 Subaqueous

6.9.6.2 Partial water cover

6.9.6.3 Wetland covers

6.9.7 Impact Mitigation

6.9.7.1 Attenuation

6.9.7.2 Dispersion

6.9.7.3 Stream Flow Regulation

6.9.7.4 Water recycle and reuse

6.10 Secondary Impacts

6.11 Evaluation of Alternatives

6.12 Design and Construction Considerations

6.13 Maintenance and Monitoring Considerations

6.14 Closure and Long-term Considerations

6.15 ARD Prevention and Mitigation FAQ's

6.16 References