Introduction to Tailings Management

Introduction to Taili Tailings ngs Management Management

March 15, 2011

Components of a Mine

Access Roads Mill or Processing Plant

Open Pits & Underground Workings

Tailings Impoundment

Process Ponds & Water Supply Waste Rock Dumps Reclamation Soil Stockpiles

What are Tailings?  Waste product from ore

grinding & mineral extraction  Rock ground to sand and silt

sizes to maximize liberation of  metals in extraction processes

What are Tailings?  Two ore more stages of crushing typical •

Primary crushing to 12 mm

•

Fine grinding circuits

Function of Tailings Impoundments Operations:  Safe storage of tailings solids &

process water  Sedimentation & clarification

of water for reclaim to process plant  Store & attenuate floods at

mine site  Mitigate Acid Rock Potential

Function of Tailings Impoundments Closure:  Safe storage of tailings solids &

water  Polish water for release to

environment  Reclaimed to meet post-

closure land uses  Mitigate Acid Rock Potential

Challenges

•

•

Tailings dams are now largest dams in the world

Focus of intense environmental scrutiny

Tailings Management Studies Main Components Site characterization Climate Hydrology studies Geotechnical & geology studies Hydrogeology studies

Tailings Management Studies Main Components Tailings characterization Geotechnical properties Geochemical properties Technologies assessment Thickened tailings Paste tailings Filtered tailings

Tailings Management Studies Main Components Design criteria Factors of safety Seismic design parameters Design flood events

Tailings Management Studies Main Components Engineering Design Tailings staging plan Dam structures Water balance Surface water management plan

Tailings Management Studies Main Components Risk Assessment Continuous evaluation of 

environmental risks at each project development stage Enables tracking of risk

mitigation throughout design process Failure Modes and Effects

Analysis (FMEA) technique

Tailings Management Studies Main Components Environmental Management Plans

Tailings Management Studies Main Components Closure Plans Meet long-term land uses

(agriculture, industrial, etc.) Stable against landslides and

seismic loading 

erosion

Tailings Management Studies Main Components Quantities & cost estimate Initial Capital costs Sustaining Capital costs Operating costs Closure costs

Process of Design Studies

Conceptual

Pre-Feasibility

Feasibility

Preliminary Economic Assessment (PEA)

Initial project financial assessment (go/no go)

Bankable feasibility cost estimates Permitting support document 

Project Timelines Exploration -30

t = 0 yr

2

Preliminary Economic Assessment

3 Pre-Feasibility

4 Feasibility

Engineering Studies 3+ mths Conceptual Engineering

6+ mths Pre-Feasibility

12+ mths Feasibility

Environmental Studies Baseline Studies

EIA

Preguntas?