Chapter 5

5. Prediction
Last Update: May 2012

GARD Guide Chapter 5

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One of the main objectives of site characterization is the prediction of ARD potential and drainage chemistry. Because prediction is directly linked to mine planning, in particular with regard to water and mine waste management, the characterization effort needs to be phased in step with overall project planning. Integration of the characterization and prediction effort into the mine operation is a key element for successful ARD management.

Accurate prediction of future mine discharges requires an understanding of the sampling, testing, and analytical procedures used, the future physical and geochemical conditions, and the identity, location and reactivity of the contributing minerals. All mine sites are unique for reasons related to geology, geochemistry, climate, commodity, processing method, regulations and stakeholders. Prediction programs, therefore, need to be tailored to the mine in question.

Methods available for material characterization and the prediction of drainage water quality are presented in this chapter. Predictive techniques range from overburden sampling to static and kinetic geochemical tests, hydrological investigations and modelling techniques. Tests to categorize samples as either acid forming or non-acid forming are discussed, given their importance in governing the management strategies of this material.

Table of Contents

  • 5.0 Prediction
  • 5.I Introduction
    • Introduction to CMD Prediction
  • 5.2 Objectives of Prediction Program
  • 5.3 The Prediction Approach
    • 5.3.1 Acid Rock Drainage/Metal Leaching Characterization
    • 5.3.2 Prediction during Different Phases of the Mine Life
    • 5.3.3 Water Quality Prediction
  • 5.4 Prediction Tools
      • 5.4.1 Introduction
    • 5.4.2 Geological and Lithological Investigations
    • 5.4.3 Hydrogeological/Hydrological Investigations
    • 5.4.4 Introduction to Geochemical Characterization
    • 5.4.5 Sample Storage and Preparation Prior to Analysis
    • 5.4.6 Summary of Testing Requirements
    • 5.4.7 Physical Characteristics
    • 5.4.8 Total and Near-Total Solid-Phase Elemental Concentration
    • 5.4.9 Mineralogical Properties
    • 5.4.10 Net Acid or ARD Potential
    • 5.4.11 Short-Term Leach Tests
    • 5.4.12 Laboratory Kinetic Tests
    • 5.4.13 Field Methods
    • 5.4.14 Data Management
    • 5.4.15 Quality Assurance/Quality Control
    • 5.4.16 Screening and Evaluation Criteria
    • 5.4.17 Reporting
  • 5.5 Modeling of Acid Rock Drainage, Neutral Mine Drainage, and Saline Drainage for Characterization and Remediation
    • 5.5.1 Introduction
    • 5.5.2 Geochemical Modeling
    • 5.5.3 Hydrological Modeling
    • 5.5.4 Hydrogeological Modeling
    • 5.5.5 Gas Transport Modeling
    • 5.5.6 Statistical Evaluation
  • 5.6 Conclusions
  • 5.7 References
  • List of Tables
  • List of Figures