Chapter 4

4.0 DEFINING THE PROBLEM – CHARACTERIZATION 1 4.1 Introduction 1 4.2 Site Characterization Approach 4 4.2.1 Conceptual Site Model Development 4 4.2.2 Mine Phases 6 4.2.2.1 Exploration Phase 9 4.2.2.2 Mine Planning Phase 12 4.2.2.3 Construction and Commissioning Phase 13 4.2.2.4 Operational Phase 13 4.2.2.5 Decommissioning Phase 14 4.2.2.6 Post-Closure Phase 15 4.3 Sources of Acid Rock Drainage, Neutral Mine Drainage, and Saline Drainage 15 4.3.1 Surface Mining – Open Pit 17 4.3.2 Underground Mining 20 4.3.3 Waste Rock and Ore Stockpiles 22 4.3.4 Tailings Piles and Ponds 24 4.3.5 In Situ Solution Mines 26 4.3.6 Heap Leach Piles 27 4.3.7 Coal and Uranium Mining Specific Acid Rock Drainage Sources 28 4.4 Components of Site Characterization 28 4.4.1 Geo-environmental Models 29 4.4.2 Source Material Geochemical Characterization 29 4.4.2.1 Laboratory and Field Testing 29 4.4.2.2 Sample Selection 32 4.4.2.3 Number of Samples Required 34 4.4.3 Watershed Characterization – The Hydrologic Cycle 36 4.4.3.1 Climate 37 4.4.3.2 Hydrology 37 4.4.3.3 Hydrogeology 38 4.4.3.4 Site Wide Water Balance 40 4.4.4 Watershed Characterization - Assimilative Capacity of the Receiving Environment 42 4.4.5 Watershed Characterization – Biological Receptors 42 4.4.6 Watershed Characterization – Archaeology and Cultural Value 43 4.5 Selected Characterization Tools 43 4.5.1 Geophysics 43 4.5.1.1 Introduction 43 4.5.1.2 Remote Sensing 43 4.6 Summary 44 4.7 References 44