“Antamina Closure Plan:

A Top Level Practice”

Eng. Antonio Mendoza, M.Sc., MBA Environmental Manager

2010

Content

• Evolution of Environmental Regulation

• Closure Process

• Antamina Closure

Evolution of Environmental Regulation

Current Regulation

1990 1993 1998 20082002 2003 20051996

Environmental

Code Ley de

Tierras

Ley de Áreas Naturales Protegidas / Orgánica para el

aprovechamiento sostenible de los recursos naturales

Ley Gral.

de RRSS

Ley del

Sistema EIA

(SNEIA)

Ley Gral. del

Patrimonio

Cultural de la

Nación

Ley General

del

Ambiente

Reglamento

Ambiental de

Actividades

Minero

metalúrgicas

LMP para

efluentes y

emisiones

mineras

(2010)

Reglamento

Ambiental

Actividades de

Exploración

Minera (2008)

Public

Participation

Regulations

(2008)

Mine Closure

Regulations /

Environmental

Legacies

Environmental Regulatory Development in the Mining Sector

Peruvian Environmental Regulatory Development

Law establishing the

Ministry of

Environment / National

Water Authority /

Implement Water% Air

Quality Standards

Compromiso Previo

con el Desarrollo

Sostenible /

Mine Closure Law

New regulation

for Closure

Plan and

Mining

Exploration

Fiscalización

Minera

OSINERGMIN

(2010)

2009

Nueva Ley de

Recursos

Hídricos /

Implementan

ECA s Agua

2010

New Maximum

Permissible

Limits for

mining effluents

OEFA

2007

Reglamento

Ley de

Recursos

Hídricos

Ley del Sistema Nacional de Evaluación y Fiscalización Ambiental

(SINEFA) / Rgto. de la Ley del SNEIA / Política Nacional del Ambiente

ECA s Aire

Medidas para

Remediación

Ambiental

Environmental management in mining

1994

1993

1996 20082002

2001 20031995

Environmental Impact Assessment

Closure Plans

Monitoring

Preliminary Environmental Assessment - EVAP

Presentation and approval of PAMA

Life of

mine

Mining PAMA

Creation of the Adjustment Programme and Environmental Management

1997

1998 2000

1999

2004

2005

2006

2007

Mining PEMA

Running of PAMA in smelters and refineries

Public Participation

2009

2010

New Maximum Permissibble Limits for mining effluents

Closure Process

Closure Regulation

• According to Closure Regulation each mine must choice Authorized Consultant to develop a closure plan– Klohn Crippen Berger Consultants elaborated the

Antamina Closure Plan

DS No. 039-2005-MEM/AAM.

Closure Objectives

• Safety for local people

• Geotechnical Stability for mining facilities;

• Reclamation of landscape

• Water protection of receiving water from mining process

• Post closure land uses as comparable as preoperational uses

Main Steps of Closure

Closure plan has these main steps:

i) Progressive Closure, during the life of mine;

ii) Temporary Closure, in case of temporary stop of activities.

iii) Final Closure, Activities to guarantee the best performance when

the mining activities ceased.

iv) Post - Closure, Monitoring of performance after closure. No less than

five years.

Objectives of Closure

The Final Closure objective is to recovery all the impacted areas and

check the following items:

a) Physical Stability in Long Term.

b) Chemical Stability in Long Term.

c) Reclamation of impacted areas.

d) Alternative uses of recovery areas of facilities.

e) Evaluate the future options of recovery area and facilities.

Peruvian regulation about Closure Guarantees

According to the Mine Closure Regulation, financial guarantees for the

closure plan are:

a) Letters of guarantee or other equivalent financial mechanisms

b) Bond Policies and other insurance, without benefit of discussion,

issued by top level national or foreign entities

c) Third-party joint bond

d) A combination of these.

Antamina Closure Plan

Antamina Location

• Mine site : Located in the Peruvian

Andes, Callejón de Conchucos,

district of San Marcos, province of

Huari, region of Ancash.

270 Km. North-east of Lima.

• Altitude: 4100 to 4700 meters above

sea level.

• Port Facility: Punta Lobitos

Pacific Coastline

300 km North of Lima.

Lima

Minesite“Punta Lobitos”

Project History

Long history of artisan mining operation

1996 Privatization process

1996 Exploring Assessment

1997 Metallurgical Pilot Plan

1998 Project Start Up

2001 Operations begins - May

2001 Commercial Goal – October

Main Closure objectives

The closure goals include:

General

• Accomplish of Peruvian regulation.

• Accomplish of additional EIA commitments

• Accomplish of additional commitments with communities and other third

parties.

• As far as possible, the design of the closure plan will offer a "passive"

closure condition and will minimize the care and maintenance

requirements to.

Closure Criteria

Open Pit

• The pit will not be filled out at closure.

Waste Rock Dump

• Rock dump overall slope should be stable in the long term.

Tailings Dam

• Verify that the slope stability of the dam is sufficient to withstand the

maximum credible earthquake.

Criterion for the Geochemical Stabilization

The objectives of water quality for site effluents are the maximum

permissible levels of mining effluent discharge, set out in the effective

legislation.

Closure Criteria

Criteria for Revegetation

• Revegetation is carried out according to defined land use at closure.

Criteria for Aquatic Habitat Rehabilitation

Maintain the quality of surface water bodies located near the project area.

Social Programs

Includes the development of optimal social programs in order to mitigate

and / or prevent potential negative social impacts related to project

closure.

Community participation in the implementation of land use at closure is

important to ensure sustainability of the ecological environment.

Closure Criteria

• Table 1.8 Design criteria for physical stability

Closure Criteria

Criteria for Revegetation

• We will be able to update

the water Quality

standards according to

new regulation

Post-Closure Criteria

Criteria for Post-Closure stage

• Implementing monitoring programs of surface water and groundwater.

• Passive maintenance of reshaping works after the first rainy season.

• Surveillance of the study area during the monitoring and maintenance.

• Social monitoring of the surrounding communities and the radius of

influence of the study area.

• Evaluation of environmental quality results in soil and water

components after the first year of remediation of environmental

legacies.

Antamina approach

Antamina is developing the following researches:

• Waste Rock Research

In collaboration with The University of British Columbia and Teck.

Geochemical and hydrological behavior of waste rock.

Antamina has implemented a research with field experimental

waste

rock piles and field cells under site conditions.

Input to improve the waste management during the operational

activities.

• Cover Study Research

To identify the most efficient cover to reduce the oxygen diffusion and

water infiltration.

• Test Plots Study

To identify the best option for revegetation using the less tick

of top soil

to be used during closure

Waste Rock Study

Test Plot

Antamina approach

To prevent failures in the closure plan, Antamina has decided to:

• Identify the components of greatest impact on the closure plan:

Tailings dam Physical impact / Chemical impact

Waste Dumps Physical impact / Chemical impact

Open pit Physical impact / Chemical impact

• Develop studies and activities required to manage the physical impact:

likely to be built and maintained in the long term.

• Develop self-research to control the chemical impact of the closure plan.

• Confirm the sustainability of activities in the long term.

Closure Components

According to the Mine

Closure Law

It is the duty of the mining

companies to provide

financial guarantees for the

closure of mines.

Financial Guarantee of Closure

amendozaz@antamina.comThank You!

Av. El Derby 055, Torre 1, Piso 8. Santiago de Surco. Lima 33 - PerúTelf. (51-1) 217-3000

www.antamina.com