Original EA Amendment

Abbreviations .................................................................... iii

Tableof contents

1 Introduction ............................................................. 1

1.1 Background................................................................................ 1

1.2 Purpose of this report ............................................................... 2

2 Site description ....................................................... 3

2.1 Site geology ............................................................................... 3

3 Record of site visit .................................................. 4

3.1 Purpose of visit.......................................................................... 4

3.2 Weather....................................................................................... 4

3.3 Observations.............................................................................. 4

4 Basis of design ........................................................ 5

5 Dam break and Consequence Category

assessment.............................................................. 7

6 Tailings and water management ............................ 8

6.1 Water storage............................................................................. 8

6.2 Deposition .................................................................................. 8

6.3 Decant pond ............................................................................... 8

6.4 Spillway ...................................................................................... 8

7 Concept design ..................................................... 13

7.1 Site access ............................................................................... 13

7.2 Foundation preparation .......................................................... 13

Upper ........................................................................................ 13

Mundic Gully rock-slope stability .......................................... 13

7.3 13

7.4 Tunnel plug .............................................................................. 13

7.5 Embankment staging .............................................................. 13

7.6 Seepage management............................................................. 14

7.7 Spillway .................................................................................... 15