Tailings Facility Management Plan In accordance with the provisions of STAS 4273-83 "Hydrotechnical

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  • Tailings Facility Management Plan

  • Roşia Montană Gold Corporation S.A. - Report on Environmental Impact Assessment Study Tailings Facility Management Plan

    Table of Contents - iii -

    Table of Contents 1 General Data................................................................................................................ 7

    1.1 Introduction ........................................................................................................... 7 1.2 Identifying Information........................................................................................... 8

    Project Name: .................................................................................................................. 8 Information on the Title Holder, Designer, Expert............................................................ 8 TMF Location................................................................................................................... 8

    1.3 TMF Functions Class and Category of Importance Technological Parameters.... 8 TMF Functions................................................................................................................. 8 Class and Category of Importance .................................................................................. 9 Technological Parameters ............................................................................................... 9

    1.4 TMF Components and Staged Construction Characteristics................................ 9 Secondary Containment System (SCS) Dam and Sump .............................................. 13 Slope Runoff Diversion Channels.................................................................................. 14 TMF Service roads ........................................................................................................ 14 Electrical Power Supply ................................................................................................. 14 Monitoring System ......................................................................................................... 14 Emergency Response System ...................................................................................... 14 Semi-passive Seepage Treatment System, after TMF closure ..................................... 15

    1.5 TMF Operation.................................................................................................... 15 2 Site Characteristics and Completed Investigations.................................................... 16

    2.1 Geology............................................................................................................... 16 Regional Geology .......................................................................................................... 16 Surficial Geology............................................................................................................ 16 Geological Basement..................................................................................................... 19 Structure ........................................................................................................................ 20

    2.2 Hydrogeology...................................................................................................... 20 2.3 Geotechnical Conditions ..................................................................................... 22

    TMF Main Dam (Corna Dam) ........................................................................................ 22 Secondary Containment Dam Site ................................................................................ 23

    2.4 Seismicity............................................................................................................ 24 3 Tailings Geochemistry................................................................................................ 26

    3.1 Available Data..................................................................................................... 26 3.2 Tailings Characterization .................................................................................... 26 3.3 TMF Decant Water Chemistry ............................................................................ 30

    TMF Decant Water Chemistry ....................................................................................... 30 Cyanide Degradation Chemistry in the TMF Decant Water........................................... 31

    3.4 Seepage Chemistry and Modelling ..................................................................... 35 Starter Dam Seepage .................................................................................................... 35 Final Dam Seepage ....................................................................................................... 37 Secondary Containment Dam Seepage ........................................................................ 38 Modelling of Contaminant Transport.............................................................................. 39

    4 TMF Technical Characteristics................................................................................... 41 4.1 Design criteria for TMF ....................................................................................... 41 4.2 Dam Raises (Lifts) Construction Data and Material Specifications..................... 42 4.3 Seal and Drainage Works ................................................................................... 45

    Starter Dam: .................................................................................................................. 46 Final Dam ...................................................................................................................... 48 Secondary Containment Dam........................................................................................ 49

    5 TMF Operation ........................................................................................................... 51 5.1 TMF Preparation for Operation ........................................................................... 51 5.2 TMF Start-up Procedures ................................................................................... 51 5.3 Normal Operating Procedures ............................................................................ 53

  • Roşia Montană Gold Corporation S.A. - Report on Environmental Impact Assessment Study Tailings Facility Management Plan

    Table of Contents - iv -

    Tailings Delivery and Distribution System. .................................................................... 53 Process Water, Precipitation and Upstream Flood Management.................................. 54 TMF Seepage Management .......................................................................................... 55

    6 TMF Organizational Structure And Monitoring System.............................................. 57 6.1 Configuration, Roles and Responsibilities of Various Organizational Structures 57 6.2 TMF Monitoring System and Actions .................................................................. 60

    Construction Phase Monitoring...................................................................................... 60 Operational Phase Monitoring ....................................................................................... 60 Inspections and Reporting ............................................................................................. 64

    6.3 Closure Phase Monitoring................................................................................... 65 6.4 Post-closure Phase Monitoring ........................................................................... 65

    7 TMF closure ............................................................................................................... 67 7.1 Assessment of Water Management Associated with the TMF during Closure and Post-closure ...................................................................................................................... 67

    Supernatant Water Management and Treatment .......................................................... 67 TMF Seepage Management and Semi-passive Treatment during Closure and Post- closure [ ......................................................................................................................... 69 Cyanide.......................................................................................................................... 70 ARD Water and Metal Content ...................................................................................... 70 Sulphate......................................................................................................................... 70 Seepage Collection and re-pumping system and return pipes ...................................... 70

    7.2 Tailings Cover and Revegetation........................................................................ 71 8 Utilization of Best Available Techniques (BAT) and Best Environmental Practices (BEP) 73

    8.1 General Principles of BAT:.................................................................................. 73 8.2 Management throughout the Project Life............................................................ 73

    Design Phase ................................................................................................................ 73 Construction Phase ....................................................................................................... 75 Operational Phase .........................................................