Charla Magistral Sostenibilidad

8/16/2019 Charla Magistral Sostenibilidad

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Jochen Smuda: Desarrollo sostenible en la minera

I. Definición y motivaciónII. Mineria polimetalicaIII.Problemas ambientales principales

de mineriaIV. Gerenciamiento del manejo

ambiental

V. Desarrollo sostenible de la actividadminera


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Motivaciones



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10 g oro


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1 ton

2% pirita

2% pirita=> 20 kg pirita= 167 molespirita=> 667 moles H+

=> 333 molesH2SO4 = 32,67 kg H2SO4 0.5 g oro/t



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CHUQUICAMATA DEPOSITEEXOTICA DEPOSITE

LEACHED ZONE

OXIDATION ZONE

ENRICHED ZONE

MINERALIZED BEDROCK

MINERALIZED GRAVEL

BARREN GRAVEL

6 km 4.5 km

PRIMARY ZONE

PRIMARY ZONE



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Mining

Waste-dump

SULFIDE-ORE Tailings impoundment

Waste material of

Crushing

Milling

Flotation

Cu-sulfide-ore99 %

Gold-ore99.9 %

Including“non-economic” sulfides E.g., pyrite, enargite, galena, ...



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J h S d D ll ibl l i


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After Mining Waste-dump

Tailings impoundmentPit-lake

ORE

ORE


J h S d D ll t ibl l i


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Differencias entre relaves y botaderos

relaves botaderos

O2 O2H2OH2O


J h S d D ll t ibl l i


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Procesos que producen acidez

Oxidación de sulfuros (e.g. pirita)FeS2 + 7/2O2 + H2O --> Fe2++ 2SO42- + 2H+

Fe2+ + 1/4O2 + H+ Fe3++ 1/2H2O (catalizado vía bacterias e.g.,

A.ferrooxidians)

FeS2 + 14 Fe3+ + 8H2O --> 15 Fe2+ + 2SO42- + 16H+ (2H+)

Hidrólisis

Fe3+ + 3H2O --> Fe(OH)3 + 3H+

Transformación (jt & sh => gt)

KFe3(SO4)2(OH)6 = 3FeO(OH)+ K+ + 2SO42- + 3H+

Fe8O8 (OH)6SO4 + 2H2O = 8FeO(OH)+ SO42- + 2H+




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Neutralización

CarbonatosCaCO3 + H+ = Ca2+ + HCO3- calcita

pH 7

FeCO3 + H+ = Fe2+ + HCO3- siderita pH 5

Hidróxidos

Al(OH)3 + 3H+ = Al3+ + 3H2O gibbsita

pH 4.3

Fe(OH)3 +3H+ = Fe3+ + 3H2O ferrihydrita

pH 3.5

Silicatos

2KAlSiO3O8 + 9H2O + 2H+ = Al3Si2O5(OH)4 + 2K+ + 4H4SiO4

K-feldespato caolinita

pH

Fe(OH)3

Al(OH)3

siderita

calcita

73 4 5 6




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pH

SeO42-

S

O

42-

CrO42-

HVO42-

AsO43-

Cr3+Pb

2+Cu

2+

Cd2+

Zn2+

Ni2+

Ca2+

HMoO4-

8 10 12642

6 7 85430

20

40

6080

100

0

20

40

60

80

% b

o u n d

t o s u r f a c e

% b

o u n d t o s u r f a c e

after Dzombak & Morel, 1990;

Mo data from Goldberg & Forster, 1998

oxyanions

bivalent cations

Liberación de metales



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Melanterite

(Fe2+

, Cu, Zn) SO4·7H2O

Jochen SmudaJochen Smuda: Desarrollo sostenible en la minera


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Jochen Smuda Jochen Smuda: Desarrollo sostenible en la minera



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Jochen Smuda

Step Name Description

1 Establish the context Define policy, purpose, objectives, success criteria, assessmentendpoints, and receptors

2 Identify the risk Define sources, pathways, concerns, and consequences

3 Analyze the risk Calculations (identify concerns and possible outcomes); certaintyand uncertainty

4 Assess and prioritizerisks

Compare with criteria; prioritize

5 Manage (treat) therisks

Mitigation, communication; develop and implement contingency andmanagement plans

6 Review and monitor Risk management plan; continue reviewing and monitoring; assesseffectiveness of treatment




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Formación de aguas ácidas (ARD)

Capturación de ARD Instalación de un

muro reactivo

(precipitación de

súlfuros)

Instalación de una

cubierta

Tratamiento

(hydrometalúrgico)

Wetlands

(precipitación de

súlfuros)

Retratamiento y

depositación segura

Muy caro

Costos a largo

plazo




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ARD Treatment - Treatment

Plant

precipitation

e.g. BaCl2Ion exchange

sorption

settling or filter

purified wate

dam

AMD

Advantages: recovery of most metals

possible, sometimes economically

Disadvantages: expensive, long term,

toxic waste

well

J



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ARD Treatment - wetlands(natural or constructed)

purified water

dam

AMD

Advantages: sulfide precipitation of

metals, economical

Disadvantages: no selective recovery,

long term, toxic waste which

has to be maintained anoxic

SO42- + 2CH2O => H2S +

2HCO3-

Me2+ + HS- => MeS(s) + H+

sulfate reducing bacteria

(SRB)

J


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Sulfur Excreting Thiobacillus



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ARD Treatment - permeable

reactive barrier

Advantages: passive in-situ treatmentPrecipitation of metals as sulfides,

economical

Disadvantages: no selective recovery,

long term, limited lifetime,

toxic waste has to be maintained anoxic

AMD plume

dam

sulfate reducing bacteria

(SRB)

SO42- + 2CH2O => H2S +

2HCO3-

Me2+ + HS- => MeS(s) + H+

purified water

J



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Remediation Advantages: - no eolic transport

- limitation of O2 and H2Oinput

Disadvantages: - expensive

- can not be used for

oxidized tailings

AMD plume

1. cover

AMD plume

2. revegetation Advantages: - green -> ecological

image

- may limit eolic transport- can be applied on a soil

cover

Disadvantages: - expensive (lime, fertilizer)

- no limitation of

AMD formation



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Clasificación de la roca

de mina en AP y NPe.g. súlfuros, carbonatos,

alteración

Flotación de los

relaves(pirita)

Evitar la oxidación

mezclar

Material

geoquímicamente

seguro

Evitar la

movilización

Prevención de aguas

ácidas Material de la mina

Mucho más economico

Menos NP

necesario



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Desarrollo de estrategias sostenibles

Relaves frescos

2 7pH

0 20

FeS2 + 7 /2O2 + H2O --> FeSO4 + SO42- + 2H+

FeS2 + 14 Fe3+ + 8H2O --> 15 Fe2+ + 2SO42- + 16H+ (2H+)

Fe2+ + 1 /4O2 + H+ Fe3++ 1 /2H2O (catalyzed e.g., T.ferrooxidans)



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Cubierta de suelo

Cobertura geomembrana

Relaves primarios

pH

2 7

0 20

Geomembrana (HDPE)



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Cobertura fosphate de fierro

Tailings with 40 -60% Fe sulifdes e.g. pyrrhotite, pyrite

Pyrite rich material => additon of PO4-rich material and carbon-rich material

Formation of a cemented zone

2 7pH

0 20

FePO4•2H2O (e.g. strengite)



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Cobertura con carbonato

Relaves no mezclados

Relaves con carbonatos

pH2 7

0 20



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Cobertura con carbon orgánico

Relaves primarios

Relaves con carbon organico

=> consumo del oxigeno via bacterias heterotrofas

pH

2 7

0 20

Cubierta de suelo



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Relaves desulfrizados

Relaves primarios

Relaves sin sulfuros

=> Substrato sostenible

pH

2 7

0 20

Relaves sin sulfuros y con suelo/materia organica


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Mineria de Lignita, Alemania

d l


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Mineria de Lignita, Alemania


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ARDManagement

Risk ManagementProcess

Focus Areas for Risk Management Example Risk Assessment Tools

Probability Consequences UncertaintyCharacterization Risk assessment Sampling Heterogeneity RepresentativenessTesting methods

MineralogyTemporal variability

Spatial variability

Potential problem assessment (PPA)Tier approach

Prediction Risk assessment Testinginterpretation

Seepage characteristics Assessment criteriaTesting duration

Particle size effect

Ecological and human health riskassessment

Prevention Risk management System malfunction Seepage characteristicsEffluent quality

Waste variabilityClimatic variability

Engineering reliability analysis (e.g.,FMEA)

Treatment Risk management System malfunction Effluent quality Sample holding time

Sample preservationTesting interferencesQuantitation limits

Treatment effectivenessInfluent quality

Influent quantity

Engineering reliability analysis (e.g.,

FMEA)

Monitoring Risk management Sourcecharacteristics

pathway analysis

Assimilative capacityreceptors

Sample holding timeSample preservationTesting interferencesQuantitation limitsSeepage variability

Assessment criteria

Ecological and human health riskassessment

Performanceassessment

/management

Risk managementContingency planningEmergency response

Human errorManagement error

System error

KPIsEffluent quality

Receiving water quality

Applicability ofperformance measures

Management system audit

Communication Risk communication Stakeholder views Stakeholder acceptance Stakeholder Values Stakeholder mapping and surveys

Sustainabilityaspects

Risk acceptance Impacts and benefits Environmentalsocial

economicgovernance

Sustainability Balance Sustainability risks and opportunitiesassessment



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Jochen Smuda


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Discipline Typical Involvement

Geology To define the geological distribution of rock types and mineralogy, for developing the geological model on which the geochemicalzones and their characterization are developed.

Mineralogy To identify minerals that control the oxidation and neutralization potential and products.

Geochemistry To evaluate the oxidation and neutralization processes, dissolution, and solubility controls that determine mine water quality,modeling of ARD, and the determination of ARD control requirements.

Mining engineering and planning To develop the mining methods and schedules for waste extraction and ore placed in stockpiles and waste rock dumps, and forintegration of the ARD management plan into mining operations.

Mineral processing/metallurgy To determine the characteristics of the heap leach, milled wastes or tailings and the control technologies that can be applied inprocessing to minimize ARD potential.

Analytical chemistry To support mine and metallurgical operations by implementing proper test methods for sample handling.

Water treatment To design water treatment plants to remove deleterious constituents in ARD and supervise water treatment plant operations.

Geotechnical engineering To design pit slopes and waste storage facilities such as tailings dams and waste rock piles, covers, and erosion stability of the postclosure drainage system and landforms.

Social sciences To ensure effective and open communication with stakeholders and to ensure that their concerns are integrated into themanagement plan.

Hydrogeology To evaluate groundwater inflows to underground and open pit mines and groundwater flows that have contact with ARD sources.

Hydrology and limnology To determine flood flows and water balance required for design water management facilities.

Soil sciences To design and implement surficial soils (covers) in the closure landscape to facilitate growth of self sustaining vegetation.

Agronomy/botany forestry To evaluate sustainable vegetation to meet the management plan and closure objectives.Biology/ecology To evaluate ecological impacts of residual surface and groundwater contamination and establish conditions for ecosystems of

restored lands that meets operating and closure objectives.

Environmental law To determine the regulatory requirements that the mine needs to comply with

Accounting and financialmanagement

To estimate and monitor costs, and make appropriate provisions for funding the management plan and sustain post-closuremonitoring and maintenance requirements.

Contract management To ensure that ARD management plan issues and measures are incorporated into all relevant contracts that the mine enters into with suppliers and contractors.

Project management andsupervision

To manage and supervise all aspects of management plan development and implementation, including long-term post closureactivities, where applicable.

Senior management To ensure management plan adherence, implementation and continuous improvement are incorporated into the key performanceindicators of all relevant personnel.



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Los retos futuros... Mejorara el uso de los recursos

... Minar los desechos (... reciclar...)... Desarrollar nuevas tecnologias de trabajar maslimpio... Desarrollar nuevas estrategias para cierres

sostenibles... Incorporar el desarrollo sostenible de lascomunidades vecinos



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Charla Magistral Sostenibilidad

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