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Modelo de acidente de ruptura de

barragem

Ildeberto Muniz de Almeida

Agradecimentos: AFT Mário Parreiras

AFT Ivone C Baumecker

Min do Trab e Emprego (MTE)

Setor de Vigilância

MS - SUS

Auditoria do MTE

Hierarquia de Estruturas de Controle de Segurança

Governo, políticas & orçamento

Corporações reguladoras, sindicatos e associações

Planejamento, orçamento e governo Local

Gestão e planejamento da Empresa

Processo físico e atividades dos atores

Equipamentos & em torno

Políticas e práticas da empresa

Sindicatos de Empresas

e empregados

Gerente da empresa

Min de Minas & Energia

Min do Meio Ambiente

CREA

Aprovação e gestão dos projeto de barragem e

de sua ampliação

Gestão da construção e ampliação da barragem

Gestão de SST

Gestão da operação da barragem

Motoristas de caminhões Operadores de escavadeiras e máquinas pesadas

Gestão da produção da mina

Unidade de Meio

Ambiente

Unidade de Meio Ambiente (FEAM)

MTE


MS - SUS

Auditoria do MTE

Hierarquia de Estruturas de Controle de Segurança e constragimentos

Governo, políticas & orçamentoCorporações reguladoras, sindicatos e associações

Planejamento, orçamento e governo local



Equipamentos & entorno

Políticas e práticas da

empresa

Sindicatos de Empresas e empregados

Gerente da empresa



CREA

Aprovação e gestão dos projeto de barragem e de

sua ampliação


Gestão de

SST




Unid de MA


Política Nacional

Legislação de M-A Legislação de SST

Concepçao de

polit. e estrat de

auditoria/ vigilânciaConcepçao de polit. e

estrat de auditoriaAprovação de projetos de

construçao e ampliação

S

N

Pol. de SST

Audit externas, inspeções e anál. de acidentes

Pol local/reg de MA

RIMAARTSubmeter projetos

Boas técnicas

Dec.

internas,

superv,

audit, anál.

Acid. e vig.

Boas técnicas

Controle de Ql

Supervisão

da

percolagem

Supervisão

da injeção de

rejeitos

Condições da barragem,

superv de planos de

implementar /aumentar,

Aspectos boas técnicas: padrões de segurança, est. geotécnicos,

cálc estruturais, sist de percolagem, análise de riscos, etc.

Projeto

Determinação das ações de

controle inadequadas e que

falharam em manter o necessário

constrangimento de segurança

MTE


MS - SUS

Auditoria do MTE

Hierarquia de Estruturas de Controle de Segurança, constragimentos (“enforcements”) e adaptações locais

Governo, políticas & orçamentoCorporações reguladoras, sindicatos e associações

Planejamento, orçamento e governo Local



Equipamentos & entorno

Políticas e práticas da

empresa

Sindicatos de Empresas e empregados

Gerente da empresa



CREA

Aprovação e gestão dos projeto de barragem e de

sua ampliação


Gestão de

SST




Unid de MA


Política Nacional

Legislação de M-A Legislação de SST

Concepçao de

polit. e estrat de

auditoria/ vigilânciaConcepçao de polit. e

estrat de auditoriaAprovação de projetos de

construçao e ampliação S

N

Pol. de SST

Audit externas, inspeções e anál. de acidentes

Pol local/reg de MA

RIMA

Projeto não

submetido

*

.

* Ausência de adesão a aspectos boas técnicas

Falha no leiaute de dutos de drenagem; elevação feita em cima de área já elevada

*

Adaptation: Map of the accident analysis according Rasmussen suggestion.

Government, policy & budgeting

Regulatory bodies, & Associations

Local Area goverm, planning & budgets

Company planning & Mngmnt

Physical process and actor activities

Equipment & surroundings

National policy

General environment protection requirements

National Envir. Protection Policy

National work Health & Safety Guidelines & policy

Design of HS audits policy / strategies

Design of E audits policy / strategies

Dam construction/raising project approval?

Budgets Regional and local policy

(objectives, priorities, resources,

etc): audits, inspections and

accident analysis

Design of HS policy / strategies

Dam raising safety plan effective?

Resources and staff effective

NoYes

No Yes

Only architectonic

project had been

elaborated

Loc or reg Envir policy

Project not

submitted to Min Previous FEAM inspections

detects no problems in Dam

project or execution

No HS inspection

during Dam raising

NoYes

Dam

instability

No

percolation

project

Critical event:

Dam raise is

made over area

already raised

Failure in

lay out of

drain tubes

Int Safety Env plans and

oversight effective?

NoYes

Crit event:

Dam wall

infiltration

Delay in problems

recognition

No study

about geo

techn stability

Dam’s percolation

isn’t supervised

Reject is being

bombed into trench 1

Trucks and “tracked

excavator” are over

dam’s wall

Dam

rupture

3 trucks, 1 tracked excavator are

destroyed

The river is affected

1 Km area is covered by rejects

5 workers died

Workers and equipment

over the dam’s wall

Mngnmt, Envir and Safety policy and practices effective?

No Yes

Wall heighted

13 m over the

planed

Competence & education

Worker’s plan effctive?

Yes No

Determine the various explanations for the

inadequate control based on the standard

components of a control loop

Alças de controle e falhas estabelecer e no “fazer cumprir” medidas de prevenção

1. Alça controle do projeto da barragem – nível de planejamento e gestão da empresa:

1. Falha na solicitação de projetos (gestor de projeto)2. Falha na designação de responsável pelo projeto

1. Recém formada3. Falha na supervisão/acompanhamento de projeto

(UM-A; GSST; Gerência empresa ...)1. Projeto só arquitetônico2. Ausência: de cálculos estruturais; de estudo

geotécnico; de projeto de percolagem; de análise de perigos e riscos

4. Falha na definição de variáveis a serem acompanhadas na execução do projeto e operação da barragem:1. Ausência controle de percolagem e infiltrações

...

Falhas em alças de controle para fazer cumprir medidas de prevenção

• Alça Governo–Empresa:

– Ausência de responsável pela aprovação do projeto de barragem

• Alça Regulador (CREA)-Empresa:

– Checa apenas profissão do responsável pelo projeto.

Falhas em alças de controle para fazer cumprir medidas de prevenção

• Gestor da empresa / gestão de produção:

– Falha na explicitação de modelo de processo (quem designar e que pedir sobre barragem a construir?) e;

– Modelos de comportamento do sistema (Considera risco de ruptura? Como controla?)

– Falha da definição de feedback do processo.

• Gestor de desenvolvimento e execução de projetos

– Falha na definição de variáveis a serem acompanhadas na construção, elevação e operação da barragem

Possible Partial Control Diagram to Dam project - 1

Project development manager

Model of

process

Model of interfaces: good techniques,

health, safety and environmental compliance

Reports and formal communication

Disturbances

Process output:

Projects (partial or final)

Process inputs: press bottom

Dam construction and raising projects

Models of

process

Company manager or Dam operation mngmnt

Models of the system

behaviour

Actuators: No automatic devices

Hazards: dam rupture, material loss, environmental impact

Constraint: percolation monitoring, raising inspections, etc.

Process: dam raising

Demand

of project

Feed back: reports about

project development

and final project

Variables controlled: structural

calculus, geotechnical analysis,

plans for percolation and control

of infiltrations, hazard analysis,

evaluation of stability of dam wall,

etc

Possible Partial Control Diagram to Dam project - 2

External Project development manager

Model of

process




Disturbances

Process output:

Projects (partial or final)


Dam construction and raising projects

Models of

process



behaviour





Demand

of project


project development

and final project

Variables controlled: structural calculus,

geotechnical analysis, plans for

percolation and control of infiltrations,

hazard analysis, evaluation of stability of

dam wall, etc

Possible Partial Control Diagram to Dam project –Local adaptation

External Engineer hired to sign dam / raising project

Model of

process




Disturbances

Process output:

Project signed by external engineer


Dam construction and raising projects signedModels

of process



behaviour





Demand

of project

Feed back: reports

about final project

Variables controlled: structural calculus,

geotechnical analysis, plans for

percolation and control of infiltrations,

hazard analysis, evaluation of stability of

dam wall, etc

Environmental controllers:

Model of process: emphasis on Env. impact

Model of interfaces: “in situ” (mainly oversight of environmental rules compliance. Secondary (?) aspects may involve

percolation, infiltrations,

documentation analysis, etc


DisturbancesProcess inputs: press bottom

Models of

process

Dam operation mngmnt


behaviour





Demand

of control

Variables controlled: Percolation

conditions, infiltrations, hazard

analysis, stability of dam wall, etc

Environmental rules compliance

Are there environmental risks?

Feed back: reports about compliance or

no compliance,

possible consequences

Process output:

If Yes, establish recommendations or

procedures and present to dam

operation mngmnt or other responsible.

Possible Partial Control Diagram to Dam construction and oversight - 1

Environmental controllers:

Model of process: emphasis on Env. impact

Model of interfaces: “in situ” (mainly oversight of environmental rules compliance. Secondary (?) aspects may involve

percolation, infiltrations,

documentation analysis, etc



Models of

process



behaviour





No

Demand

about

control


conditions, infiltrations, hazard

analysis, stability of dam wall, etc

Oversight Environm rules compliance

Are there environmental risks?

Feed back: No reports about no

compliance with good

techniques in dam raising

process

Process output: oversight of

environmental rules compliance not

exploring technical aspects of dam raising process.

Possible Partial Control Diagram to Dam construction and oversight – 1: local adaptations

Safety manager controller:

Model of process: emphasis on Env. HS risks

Model of interfaces: “in situ” (mainly

oversight of health and safety

compliance. Secondary aspects may involve

percolation and infiltrations analysis


Disturbances

Process output:





Oversight Health-Safety compliance

Are there health and safety risks?

Models of

process



behaviour





Controls


conditions, infiltrations, stability of

dam wall, etc


no compliance,



Safety manager controller:

Model of process: emphasis on Env. HS risks

Model of interfaces: “in situ” (mainly

oversight of health and safety

compliance. Secondary aspects may involve

percolation and infiltrations analysis



Oversight Health-Safety compliance


Models of

process



behaviour







dam wall, etc


No

Demand

about

control




process

Process output: oversight of Health

and safety compliance not

exploring technical aspects of dam raising process.

Dam operation controller:

Model of

process

Model of interfaces: “in situ” direct oversight of project, H, S & E rules

compliance including good techniques

application, percolation and infiltrations analysis, etc.


Disturbances

Process output:





Project compliance


Models of

process

Company manager


behaviour





Controls



dam wall, etc


no compliance,



Dam operation controller:

Model of

process

Model of interfaces: “in situ” direct oversight of project, H, S & E rules

compliance including good techniques

application, percolation and infiltrations analysis, etc.



Oversight of project compliance

Are there flaws or risks?

Models of

process

Company manager


behaviour







dam wall, etc


No

Demand

about

control




process

Process output: No oversight of good techniques

compliance.

Workers controllers (truck drivers and others)

Model of

process

Model of interfaces: bring raw materials

using trucks, control of technical aspects and

safety constraint, etc …



Dam wall being raised

Models of

process

Dam operation manager ?


behaviour





Variables controlled: trucks and

excavators circulation, dam height,

qt of material used, etc

Possible Partial Control Diagram to Dam raising and oversight:

Demand

dam

raising

Process output: Dam reaches

planned height.


project development

Workers controllers (truck drivers and others)

Model of

process



Dam wall raised 13 m over the

planned

Models of

process

Dam operation manager ?


behaviour





Variables controlled: flaws in

control of trucks circulation, dam

height and stability, etc

Possible Partial Control Diagram to Dam raising and oversight: Accident situation

Demand

dam

raising

Process output: Dam rupture

Feed back: No reports

about project development

Model of interfaces: lax control of

technical aspects and safety constraint, etc

…

Contextual aspects: no control of dam percolation, no detection of dam wall

infiltration, project has no structural calculus, etc. External Environmental protection Agency

audit detects no problem related to dam stability.

Risk of dam rupture

Risk of being reached in case of dam rupture

Dam raising project approval

Project

compliance

to safety

standards

Project

compliance to

hazards

analysis

Previous

Geotechnical

studies

Project with

previous

structural calculus

Percolation

oversightDam conditions

and raising plans

implementation

oversight

Project with

Percolation

system

Oversight dam

feed plans

(rejects

injection)

Oversight dam

conditions and dam

raising plans

Oversight

rejects

injection.

RIMA

approval

External

inspections

Compliance to

the project

Ad equation

of

inspections

plan

+++

+

+

+

Elaboration

of (only)

architectonic

project

_

+

+

_

__

_

_

_

+ +

++

+

+

++

+

++

+

A system dynamics model for the dam raising.

+

+

+

+

Percolation

evaluation

plan

+

+

+

+

+

+

Risk of dam rupture

+

A system dynamics model for the dam raising.

Raising dam

without

structural

project

Raising

Dam

without

compliance

of safety

standards

Raising dam

without

hazards

analysis

Raising dam

without

geotechnical

studies

Raising dam

without structural

calculus

Raising dam

without project of

percolation

system

Raising

dam

without

RIMA

Dam raising project approval

__

__ _

_

No

percolation

oversight

No oversight of

Dam conditions

and raising plans

implementation

No plans about

oversight dam

feed (rejects

injection)

No plans about

oversight dam

conditions and dam

raising

No oversight

of rejects

injection.

No plan

about

percolation

evaluation.

External

inspections

Ad equation of

inspections

plan

Enterprise

fear of

punishment

Enterprise

safety culture

Dam raise is

made over area

already raised

Failure in

lay out of

drain tubes

Dam wall

infiltration

++

+ ++

++

Delay on

infiltration

detection

+

+

+ ++

++

+ ++

++

++

Cascade (Falls) of positive

influences going to the accident.

++

+

+

Conclusions

Conclusions

Control flaws leading to Hazards: Dam rupture• 1.2) Inappropriate, ineffective, or missing control actions for

identified hazard

• 1.2.1 ) Design of control algorithm (process) doesn’t enforce constraint,

• Flaw(s) in creation process,

Min of Mines and energy

• Flaws in control of technical aspects of project: previous approval? Specific guidelines?

• Reason: Failure in model of process: Underestimation of risk of HE? Risk “normalization”? (Brazilian aspect) Production pressures?

Min of Environmental Protection

• Flaws in program to control risks/losses in Dam constructions

Min of Transport, Min of Health and Min of Labour:

• Flaws in program or plan to control safety in Dam constructions.

• Reasons: Failure in model process. Cultural aspect: technical requirements of the process aren’t considered as safety problems.

CREA (engineer’s council)

Control flaws leading to Hazards: Dam rupture

• 1.2.1 ) Design of control algorithm (process) doesn’t enforce constraint,

• Flaws in creation process

Company manager

• There’s no enforcement to establish safety constraint during dam’s project elaboration and implementation. Neither constraints (technical, safety and environmental requirements, trainings, oversight …) nor responsibilities are clearly established. Construction and raising were developed only with an architectonical project.

• Incorrect modification or adaptation:

Company manager (Dam operation, Safety and Environment mngmnt)

• Project establishes dam raising over area already raised.

• Reason: Failure in model of process

• 1.2) Inappropriate, Ineffective or missing control actions for identified hazards. (Cont):

• 1.2.2) Process models inconsistent, incomplete, or incorrect (lack of linkup)– Flaws in creation process:Min of Mines & Energy:– Dam construction and operation weren’t monitored.

• Reasons: inadequate mental model about the process? Contextual factors as lack of resources (budgets reductions?) Conflicting policies? …

– Flaws in updating process (asynchronous evolution):Company management:– ..


• 1) Inadequate enforcement of constraint (control actions) (cont).

• 1.2.3) Inadequate coordination among controllers and decision makers:Min of Labour, Min of Health and Min of Environmental Protection (federal,

regional and local levels).– Lack of constraint to establish oversight of the dam construction and

raising. There’s overlap of attributions among national, regional and local HSE authorities without ways to coordinate the actions of these three areas. None of these institutions oversights technical aspects of dam construction or raising.

• Reasons: Contextual factors conflicting policies? Lack of resources? No enforcement to coordinate actions …

Company management (Company manager, …)

– There’s overlap of attributions related do technical and safety compliance among Dam operation, Safety and Environmental managements. None of them assumed the responsibilities maybe thinking that they belong to the others

• Reasons: Inadequate mental models about process (underestimation of risks?). Safety and environmental areas are not considered as interlocutors during project elaboration and implementation (Organizational/cultural aspect).


2) Inadequate Execution of control action:• 2.1) Communication flaw:

Company management (Company manager, Dam operation manager, safety and environment management …)

• No enforcement to establish communication process about the risk of dam rupture and ways of prevention

Min of Labour, Min of Health and Min of Environmental Protection (federal, regional and local levels)

• There’s no exchange of information among them in relation to dam construction/raising oversight.

• Reasons: inadequate mental models about process and about furnace operation? Safety culture problems?


• 2.2) Inadequate actuator (automatic and Human?) operationMin of Labour, Min of Health and Min of Environmental Protection (federal,

regional and local levels)– Audits from Environmental protection agency didn’t identify neither

projects problems nor implementation problems (no percolation evaluation, no infiltration oversight, raising been made over areas already raised etc) ??

– Health and Safety area had no previous inspection on the dam area.Company management (Company manager, dam operation, Safety,

environmental management– Lack of enforcements to technical and safety constraints: dam wall raised

over area already raised; dam wall heighted 13 m over the planned; wall infiltration not detected, percolation not oversighted …

• Reasons: Inadequate mental model about process. Safety culture problems?


• 3) Inadequate or missing feedback:Company management, Dam operation, safety and environmental

management– 3.1) Not provided in system design:– Design of control system didn’t establish percolation and infiltration

oversight as kinds of feedback managers and operators would receive.• Reasons: Inadequate mental model about the system? Competence/

training problems? Safety culture/organizational problems? Risk normalization (Brazilian aspect: normalization without risk analysis).

– 3.2) Communication flaw– In the region there were previous dam ruptures. Why the lessons

weren’t learned?• Reasons: Safety culture problems? Failure in accident analysis

practices? Cultural aspects: accidents tends to be explained as technical phenomenon and as a consequence, managerial and organizational aspects that are part of accidents origins aren’t considered as causes.

– 3.4) Inadequate sensor operation (incorrect or nor information provided)

– Warns about flaws in dam percolation and dam infiltration couldn’t be detected. (discuss: 3.1 or 3.4???)

• Reasons:


Comments

• Most important causes seem related to lack of enforcement enterprise to establish safety constraint since begin of dam project elaboration.

• Continuous degradation of safety during a long period without enforcement of safety constraint or good techniques of dam construction are in the origins of the accident.

• Lack of supervision (oversight) of technical development of the project, lack of internal safety or environmental inspections and audits related to the risk of dam rupture contributes to avoid early detection of the problems. This problem is more important because there were previous dam ruptures in the same state (region).

• This can be pointed as aspect of Brazilian heterogeneity of safety situation, maybe his worst face. The persistence of enterprises handing with high risks technologies without any compliance related do good techniques and legal safety constraint. In these kind of enterprises Health and Safety management seems to be fragile (technical, organizational and political) structures to face this kind of challenger. Mainly in situations where they live besides these problems for long periods.

• Maybe flaws in external environmental protection agency audits of the dam raising had contributed to this process because they didn’t find any problem related do dam wall stability.

• This aspect points to the existence of flaws in government actions. Maybe there are problems in competence / training programs and the need of better coordination among the different agencies involved in audits/inspections of systems that are handling high risks technologies.

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