Planning best practice
tailings disposal,
management and
rehabilitation strategies
Presented by
Mike Gowan
The Simple Early Mining Life
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Before TSFs – Sand Dumps
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The Simple Life – Cocopan Haulage
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Before Tailings Pumping Systems
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Early TSF Construction
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TAILINGS STORAGE FACILITIES
 Named a TSF
 Includes:
Storage walls and footprint
Slurry pipelines
Return water dam
Return water system
 But they do not always “store” the
tailings
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Kalgoorlie before Kaltails
Wind and Water Erosion
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TSFs
 Largest dams ever built – seen from
space
 Unlike water dams, have to last “for
ever”
 Normally built progressively over a long
period – up to 50 years
 Often built with non-engineering
materials
 Should be considered as a living entity
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20 Years On using Tailings!
Upstream raised gold TSF
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Mining Realities
 Mining a continuous operation
 TSF at the back end of the operation
 Generally “out of sight and out of mind”
 A cash consumer, not a cash contributor
 A source of “constipation” when they go
wrong
 Do it right the first time!!!
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TSF Failures
 At least 2 TSF failures reported
annually
 Many more not reported
 Failure includes:
Wall failure
Wall breach
Overtopping
Release of contaminated liquor
Contaminated seepage
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Unreported Wall Failure
Out of Sight
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Unreported TSF Failure
No Injuries
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Unreported Contaminated Flow
“Contained”
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In-River Tailings Disposal
In river
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Result of Failures?
 Poor public perception
Omai
Baie Mare
Marcopper
Los Frailes
 Leads to a lack of trust
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Failures
 No TSF failures are unexpected
 All failures can be predicted with
hindsight
 Failures due to one or more of:
Poor design
Poor construction management
Poor operation
Changing management during
operation
Lack of rigorous and regular
inspection
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OUR DUTY AS DESIGNERS
 Carry out a rigorous design
 Provide the owner with clear
operating guidelines
 Stand-up for our role
 Record, assess and advise
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Appropriate Tailings Disposal
 Design must:
Meet project requirements
Satisfy legislative standards
Follow current engineering
knowledge
Look to better environmental
expectations
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Transportation
 Low solids content slurry
 High solids slurry
 Paste
 Cake
 Dry
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Ash - 12% Solids
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Diamonds - 45% Solids
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Gold - 70% Solids
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Tailings Placement
 Pumping
Low solids content
High solids content
 Conveying
 Trucking or railing
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Conventional
2 Stage Pumping for Codisposal
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Paste
1 MW Diaphragm Positive
Displacement Pump - Flyash
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Conveying
Dry
Flyash
Flyash
Dewatered
Tailings
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Trucking
Flyash
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Why Change?
 The drier the tailings the lower:
Water losses
Chemical losses
Risks of environmental contamination
Rehabilitation costs
 Increased risk of:
Dust
Erosion
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Dust & Erosion
Dust
Erosion
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Understand the Tailings
 Seepage
 Water quality
 Dust
 Radiation
 Instability
 Geomorphological processes
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Seepage in a Dry Environment
HDPE Liner to reduce Seepage
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Radiation
Subaqueous to reduce Radiation
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Accidents do Happen!!
The Human Element
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Mine Expansion
 Two mining realities:
The full tonnage is achieved well
ahead of schedule
More ore is found
 SO:
Plan for full tonnage earlier
Consider expansion
• Do not limit expansion through
design
• Consider the next TSF site
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Conclusion
 Endeavour to place tailings back
in mine
Legislated in California
 Plan for tailings retreatment
 Provide comprehensive
Operational Management
Documentation
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Coal Tailings In Final Void
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Paste Backfilling Underground
Paste Backfill
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In-Pit Codisposal - Gold
Tailings
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Waste
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The End
My thanks to:
Fraser Alexander for old photos
Mining clients for use of project photos
Various authors quoted without reference
My colleagues who keep me on my toes!!??
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