European Commission DG Environment Classification of mining waste facilities No. 07010401/2006/443229/MAR/G4 Final Report December 2007 Prepared by DHI Water·Environment·Health in cooperation with SGI, Swedish Geotechnical Institute and AGH, University of Science and Technology, Krakow Final Report DHI – 54152 TABLE OF CONTENTS Foreword ..................................................................................................................................................2 Executive Summary .................................................................................................................................4 1. Introduction ..................................................................................................................................12 2. Category A classification of mining waste facilities .....................................................................13 2.1 Background and intentions ...................................................................................................13 2.2 The implications of being classified as a Category A facility................................................14 2.3 The significance of being classified as a Category A facility................................................14 2.4 Discussion.............................................................................................................................15 3. Approach and overview ...............................................................................................................16 4. Review of mining waste facility classification systems ................................................................18 4.1 Introduction ...........................................................................................................................18 4.2 Mining waste classification systems within the EU...............................................................18 4.3 Classification of mining waste facilities.................................................................................20 4.3.1 The European Union ........................................................................................................20 4.2.1 Other European countries ................................................................................................24 4.2.2 Major mining countries outside Europe............................................................................24 4.2.3 Overview of mining waste facility classification systems .................................................25 5. Review of risk assessment methodologies..................................................................................27 5.1 Risk analysis - general principles and terminology...............................................................27 5.1.1 Introduction.......................................................................................................................27 5.1.2 Terminology (EEA, 1998) .................................................................................................27 5.1.3 Risk analysis.....................................................................................................................28 5.1.4 Risk assessment ..............................................................................................................29 5.1.5 Risk as a chain of events .................................................................................................31 5.1.6 Uncertainty .......................................................................................................................32 5.1.7 Bayesian decision analysis ..............................................................................................32 5.2 Examples of risk assessment models ..................................................................................33 5.2.1 The TAC-model ................................................................................................................33 5.2.2 US EPA and Superfund risk assessment.........................................................................34 5.2.3 VROM (The Dutch Directorate General for the Environment) .........................................37 5.2.4 SEPA (The Swedish Environmental Protection Agency) .................................................38 5.2.5 Probabilistic risk assessment ...........................................................................................39 5.2.6 Performance assessment of nuclear waste facilities .......................................................40 5.3 Assessing low frequency high amplitude events..................................................................41 5.3.1 Introduction.......................................................................................................................41 5.3.2 Examples of consequence classification systems ...........................................................41 5.4 Concluding remarks on risk assessment methodologies .....................................................47 6. Major types of mining waste facilities in Europe..........................................................................49 6.1 Introduction ...........................................................................................................................49 6.2 Overriding principles – life-cycle management.....................................................................49 6.3 General description...............................................................................................................49 6.3.1 Extraction and waste-rock generation..............................................................................50 6.3.2 Mineralogy........................................................................................................................51 6.3.3 Processing and tailings generation ..................................................................................51 6.3.4 Waste management .........................................................................................................52 6.4 Waste-rock management......................................................................................................52 6.4.1 Waste-rock heaps ............................................................................................................52 6.4.2 Monitoring of waste-rock heaps .......................................................................................53 6.4.3 Closure of waste-rock heaps............................................................................................54 6.5 Tailings management ...........................................................................................................55 6.5.1 Backfilling of tailings into operating underground mines..................................................55 6.5.2 Tailings ponds ..................................................................................................................55 6.5.3 Tailings disposal into old voids.........................................................................................59 6.5.4 Co-disposal of tailings and waste-rock.............................................................................60 6.5.5 Thickened and Paste tailings and Dry stacking of tailings ...............................................60 Classification of mining waste facilities December 2007 DG Environment i Final Report DHI – 54152 6.5.6 Monitoring of tailings management facilities ....................................................................60 6.5.7 Seepage flow to surface water and groundwater.............................................................61 6.5.8 Closure of tailings management facilities.........................................................................62 6.6 Future Tailings Management................................................................................................64 6.7 European mining...................................................................................................................64 6.7.1 Metal mining sector ..........................................................................................................64 6.7.2 Industrial minerals ............................................................................................................65 6.7.3 Energy minerals extraction...............................................................................................66 6.7.4 Aggregates industry .........................................................................................................66 6.8 Discussion.............................................................................................................................67 7. The amended Seveso II Directive applied to mining waste facilities...........................................69 7.1 Background...........................................................................................................................69 7.2 Mining waste facilities falling under the amended Seveso II Directive.................................70 7.3 Likely reasons why no mining waste facilities are classified as Seveso II sites...................70 8. Proposed methodology................................................................................................................73 8.1 Introduction ...........................................................................................................................73 8.2 a): Classification based on the consequences