Tecnologias para o monitoramento de rejeitos – experiência da Fugro no
desastre de Bento Rodrigues e desenvolvimentos recentes
Alessander Kormann
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Samarco Project - Locations
Source: www.samarco.com/rompimento-de-fundao/
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Samarco Structures – Germano Mine Complex
Germano Mine
complex before
Fundão dam
failure
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Setup of Fundão Dam System, early 2015
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Overview of Germano Complex after Dam Failure, 2016
Sela Dike
Tulipa Dike
Baia 3 Dike
Germano
Main Dam
Selinha Dike
Germano
Buttress
Auxiliary Dike
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Design Principle of Fundão Dam System
A) Initial design of
Fundao-dam system
with separation of course
grained sands and fine
grained suspensions
(slimes)
B) Planned layout
of Fundao-dam system
following upstream
method of construction.
Drainage system within
sandy tailings
Source: Fundao Tailings dam Review Panel
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Fundão Drainage System, 2008
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Source: Fundao Tailings
dam Review Panel
Redesign of Drainage with Blanket Drain, 2009
Installation of
1st Blanket Drain for
drainage of tailings
above an elevation
of 826m
Secondary drainage
galleries not working
properly, detected
2010
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Construction of Setback Crest, 2012
Source: Fundao Tailings dam Review Panel
In 2012 it becames evident
that secondary drainage
gallery at left abutment is
out of function.
A setback crest was con-
structed and a second
blanket drain installed at
Plateau elevation 865
Installation of piezometers
in 2014 showing increasing
saturation of the dam, even
above elevation 865
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Fundão Dam: Principle Stress Situation
Pore water pressure [u]
Load [Mean Total Stress]
Source: Fundao Tailings dam Review Panel
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Fundão Dam: Process of Failure at Left Abutment
σefective = σtotal - u
u ≥ σtotal → σefective = 0
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Principle Stress States, Drained & Undrained
UNSTABLE
STABLE
STEADY STATE
SHEAR STRENGTH
(σ1+σ3)/2 [Mean stress]
CONCEPT OF THE COLLAPSE SURFACE
(σ1-σ
3)/
2 [S
he
ar
str
ess]
5
4
3
2
1
STRESS PATHS INHERENT FROM AN INITIALLY STABLE CONDITION
(σ1+σ3)/2 [Mean stress]
(σ1-σ
3)/
2 [S
he
ar
str
ess]
Adapted from: MARTIN & Mc ROBERTS, 2012
STRESS
PATH
BEHAVIOUR ON
STRESS
ANALYSIS
METHOD
1-2-3 Contractive USA
1-4 Contractive ESA
1-4 Dilative ESA
1-5 Dilative USA
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Technologies for Site Characterization and Monitoring of Tailings
• Geotechnical Investigation (Active):
‒ Drilling (rotary and SPT)
‒ CPT
‒ Vane Tests
‒ Seismic CPT
• Geophysical Survey:
‒ GPR
‒ Electrical Resistivity
‒ Magnetometry
• Geotechnical Instrumentation (Passive):
‒ Casagrande Piezometer
‒ VW Piezometer
‒ Water Level Indicator
‒ Inclinometer
• Laboratory:
‒ Earthworks control
‒ Index tests
‒ Advanced tests
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Cone Penetration Testing (CPT)
signal cable
connection piece
for rod
water proof casing
O-rings
calibrated steel rod
with strain gauges
Inclinometer
Friction sleeve
As = 150 cm²
calibrated steel rod
with strain gauges
O-rings
Cone
Ac = 10 cm²
Penetration of the CPT
cone (hydraulic) into the
ground with a constant
speed of 2 cm/sec
Simultaneous and
continues measurement
of the total penetration
resistance, which is
divided in cone
resistance (qc) and local
sleeve friction (fs)
Additional parameters
can be measured with
added tools
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CPT – Lithologic Interpretation
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Seismic CPT
t = t0
t = t1
t = t2
Δs
Calculation shear wave velocity
t2 – t1 = Δt vs = Δs / Δt
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Degradation of Shear Modulus with Increasing Strain
G0 gemessen mit SCPT
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Germano: Main Dike and Germano Buttress – Performed Investigations
Service
Before
Fundão
Breach
After
Fundão
Breach
Drilling (m) 759.28 1476.52
Water level
indicator
(unit)
4 6
VW
piezometer 0 16
Casagrande
piezometer
(unit)
11 35
Inclinometer
(unit) 0 3
CPT (m) 362.94 134.91
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Cava de Germano – Performed Investigations/Measurements
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Case Study: Tailing Characterization for Re-mining
CPT based Technology
Deliveres geotechnical data
XRF technology - provides metal concentrations
High resolution – real time
3D modelingof resources for remining
Old tailing for remining / resource estimation
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Typical XRF-CPT profile
at Tailing1
CPT-XRF: How it Works
> 1% Cu Target Horizon
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3D Resource Estimation
Metal Distribution within Tailing Body
Metal bearing zone
> 1% Copper
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GeODin
O GeODin foi desenvolvido inicialmente por geólogos e hidrogeólogos para organizar
dados de campos e permitir seu compartilhamento. Atualmente, a Fugro usa o GeODin
em escala global, como ferramenta padrão de gerenciamento de dados.
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Estrutura
Gerenciamento de documentos
Sistema GeODin
Dados dinâmicos Estações meteorológicas
Pontos de controle de rede
Poços
Sondagens
Pontos de monitoramento
Monitoramento
Dados estáticos
GIS
Gerenciamento correto
Servidor do portal
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Monitoramento hidrogeológico com interface WebGis
Túnel Itália - Áustria
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Aquisição de Dados e Integridade
Coleta e exame dos dados: como estão organizados (estrutura), relações entre
conjuntos de dados & realidade física (topologia), origem (metadata).
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Dados Dinâmicos, Análise & Estatísticas
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Rotinas Automatizadas para Relatórios
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Município de Berlin, Alemanha
Gestão de dados regional (130.000 furos de sondagem, 8.000 poços de
monitoramento, piezômetros, qualidade da água subterrânea).
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Base de dados aberta
Dados dinâmicos
Sistema de alerta
Gerenciamento de Barragens, Alemanha
Oito barragens e reservatórios (463 milhões de metros cúbicos). Maior sistema
fluvial integrado do país.
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Companhia Siderúrgica do Atlântico, Brasil
Gestão de dados do
subsolo e de
geomonitoramento
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Considerações Finais
• Importância de abordagens integradas de investigação e
monitoramento de estruturas de disposição de rejeitos.
• Informações integradas: geográficas, geológicas,
meteorológicas, hidrogeológicas, geotécnicas, estruturais
(monitoramento).
• Evolução tecnológica: aumento da segurança na cadeia
produtiva da mineração.
Obrigado!