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1er Sem inar io d e Geom ecanica Ap l icado y Segurid adPeru 2 009
M etod os de disposicion de relaves
Riesgo sism ico
RELAVES ESPESADOSEM M ANUEL PORNILLOS
GOLDER ASSOCIATES, LIM A PERUJ
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Manejo de Relaves de la Mina - Diseno
Use Design for Closure philosophy
System approach - Water and solids managementDesign for:
Climate conditions arctic to rain forest to desert
Geological conditions
Topography
Ore types
Mine throughputManagement method selected to suit the mine
Low density slurry
Thickened/Paste Tailings
Filtered Tailings
Co-mingled/co-disposed/Paste Rock
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Manejo de Relaves de la MinaConsideraciones
Regulatory requirements
Climate - dry or wet
Topography - natural containment
Natural hazards - including seismic events
Physical stability (static & dynamic earthquake)
Chemical stability potential acid generation & leachable contaminants
Environmental / social constraints
Decommissioning & closure - progressive closure & design for closureChemical stability potential acid generation & leachable contaminants
Mechanisms for contaminant transport groundwater, surface water & air
Surface & groundwater protection downstream users
Water management minimize water usage especially in a dry climate
Erosional stability from wind & runoff
Aesthetics especially in the closure mode
Foot print limit the area of disturbance & impact
Rheology - thickening & pumping characteristics
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Metodo de Disposion de los Relaves
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Metodo de Disposion de los Relaves
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Metodo de Disposion de los Relaves
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Metodo de Disposion de los Relaves
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Porque Desaguar el Relave?
Reduce overall water use by minimizing
water losses
Reduce Footprint or Containment Structures
Simplify Closure or Reduce Closure Period
Reduce Risk of Failure
Regulation
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Reduccion de Perdida de Agua
Slurrydensity
(% solids bymass)
Volume ofwater in the
tailings(m3/ ton of
tailings)20 4.0
30 2.3
50 1.0
75 0.3
Less water transported to
tailings area = less potential for
seepage or evaporation loss
No tailings pond = less
evaporation
Higher final density = less water
retained in voids
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Minimizar el Area o la Estructura de Contencion
Dam
Capacity for Slurry
ThickenedTailings
discharge
SlurryTailings
discharge
Slope 3 to 5 %
Note:The thickened tailings must beallowed to desiccate to be stable
Additional CapacityFor Thickened
Tailings
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Alternating, thinlayer deposition
Slopes typically
3 to 10%
Tailings discharge
Thickened
tailings
Runoff collection
Minimizar el Area o la Estructura de Contencion
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Simplificar el Cierre oReducir Periodo de Cierre Period
Denser tailings = less consolidation, less cover settlement/cracking
Denser tailings = trafficable sooner, concurrent reclamation
Less segregation = lower average permeability, less seepage, less acid
generation
Less or no water to treat at end of operation
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Reducir Riesgo de Falla
Riesgo = (Probabilidad de Falla)x(Consequencia)Consequence is a function area inundated by
tailings/water after failure
Reducing quantity of water reduces area of
inundation after failure
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Construccion Aguas Abajo Reglamentado en Peru
Date Location Incident Release Impact
March 28 1965 Chile - El Cobre Liquefaction of tailingsduring earthquake leading
to dam failure and flow
slides
New Dam 350 000 m3
Old Dam 1 900 000 m3Tailings travelled 12 kmdownstream, destroyed the
town of El Cobre and killed
more than 200 people
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Diseno de Dique con Arena Relaves Cicloneada
Sand dams constructed 3 ways
Upstream has smallestconstruction quantity, but
highest risk
Downstream has largest
construction quantity and
lowest risk
Centerline smaller quantity
than downstream, similar risk
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Diques de EnvergaduraDiques de Envergadura
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Notas y Observaciones
The tailings properties and projectrequirements greatly influence the method
that is selected for disposal.
What may be good for one type of tailings orproject location may not be suitable for
another type of tailings or project location.
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ESTABILIDADRELAVES ESPESADOS DEPOSITADOS
Segun Paste 2009 Vina del Mar
La estabilidad Se requiere deposicion en CAPAS DELGADAS
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ESTABILIDAD
Que es Deposicion en Capas Delgadas?
El depositar capas delgadas les da suficiente
tiempo para que el relave receintemente puesto the
a desicar y enduricir
De-saturar que genera una succion en los matrices que redusca la
void ratio (razon volumen/volumen)
Espesor de capa diferente para el tipo del relave, la
clima, tasa de produccion, la configuracion del vaso
El material se vuelve densa (dilativa) despues de
estar remojado/re-saturado
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Caracteristicas del Material de Relaves
Depende a:Mineralogia
Proceso estractiva del mineral yreactivos
Granulometria o grado de molienda
La S.G. de particulas
Grado de espesamiento odesaguado
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0.4
0.6
0.8
1
1.2
1.4
1.6
0.1 1 10 100 1000 10000
Void
Ratio
,e
M ean Effect ive Str ess, p' (kPa)
After Deposi t ion
Bleeding
CSL
DRY
Desiccation
Consol idation
W ett ing (un load curve)
Final St at e ofTailing s in StackW i th Dry ing
Contractiv
Di lat ive
q
Final St at e of Tail ingsin Stack W itho utDrying
After Been and Li 2009
Esquematico de Relave luego de Deposicionen un Estado mas Suelto que
en Estado Critico a Esfuerzo Bajo
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(%(% solidossolidos emem peso)peso)Variabilidad d e ConsistnciaVariabilidad d e ConsistnciaPulpa d e relaves
Relaves Espesad os
Altamen te Espesado
(Pasta)
Relave Filtrad o
< 60%
60 - 70%
70 - 78%
78 - 88%
Tecnologia de Espesamiento de Relaves(Cobre, SG=2.7)
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espessadosRejeitos
No cisallado
Pasta
Relaves de cobre tipoATorta de Filtrado
Resistenciaa
o
Fluxo
(Pa)
% Slidos
Cisallado
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0. 4
0. 6
0. 8
1
1. 2
1. 4
1. 6
0.1 1 10 100 1000 10000
Void
Ratio
,e
M ean Effect ive St ress, p' (kPa)
After Deposi t ion
Densi f icat ion/Compaction
CSL
DRY
Desiccation
Consol idation
W ett ing (un load curve)Final St ate o fTailings in St ack
Contractive
Di lat ive
q
q
Esquematico Cambio de Estado Geotecnicaen los Relaves luego de la Depositacion and Densificacion
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SLURRY DENSITY (% by weight)
TailingsSlopeAngleAchieved(%)
Li, Been, Ritchie and
Welch (2009)
Las Pendientes - Playas de Relaves Espesados
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Muchas Gracias
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