tailings storage facilities insights - types, failures, tailings … · 2020. 12. 17. · tailings...

Tailings Storage Facilities; From Recent Lows to New Heights

Tailings Storage Facilities Insights - Types, Failures,

and Management Guidelines Update

52nd IMIA Conference

19th to 23rd October 2019

Hotel Savoyen, Vienna, Austria

Richard Stahl

Director International Forensics

Jensen Hughes UK Ltd.

21 October 2019

Advancing the Science of SafetyCopyright © JENSEN HUGHES. All rights reserved.

• Tailings and Processing

• Tailings Storage Facilities Overview

• Failure History Dashboard

• Mount Polley, Samarco, Newcrest, Brumandinho (Feijão)

• Upgrading Guidelines or Practices Towards Zero Failure

OVERVIEW

2


MY BACKGROUND

• B.Ap.Sc. (Civil) UBC: 1987

• Klohn Leonoff Ltd. 1987 to 1990

• U of A (Alberta) M.Sc. (bypassed) Ph.D. Geotechnical: 1990-1991, 1993-1996

• AMEC Inc.: 1993 to 1993

• GWA then Golder Associates (HK): 1996-2001

• London Business School: 2001 to 2003

• Golder Associates Ltd. 2003-2006

• Giffin Koerth then -30- Inc. 2006-2017

• Jensen Hughes UK Ltd. 2017

• P.Eng. (Canada), CEng., FICE (UK)

3


SUMMARY PROCEDURES IN MINING PRODUCTION

Grinding

Leaching HeatingConcentration

Dewatering

Concentrate EmulsionProduct

4

Ore

Waste Tailings


TAILINGS DEWATERING RANGE AND CONSISTENCY

Tailings Type Consistency

Water with Sand/Silt/Clay

Sandy Yogurt

Wet Sand

Thin Milk Shake

Moist Sand

De

creasin

g Wate

r Co

nte

nt

Pu

mp

able

No

n-P

um

pab

le

• Likely lowest operating cost• Least efficient water

conservation• Containment dams required• Potential seepage issues• Water management

considerations

Unsaturated

Saturated

Tailings Slurry

Thickened Tailings

Paste Tailings

Wet Filtered Tailings

Dry Filtered Tailings

• Water conservation • Negligible seepage • Progressive reclamation• More stable tailings mass• Minimal containment berms• Simpler water management• High operating costs 5


AN ILLUSTRATION OF TAILINGS VOLUMES - GOLD

6


• 1 g/gold/metric tonne of rock (on average)

• 2018, 3,260 metric tonnes of gold = 3.3B metric tonnes of rock mined

• Rock density of 2.6 g/cm3, bulking factor of 1.6, ►2B m3 of tailings

VOLUME OF TAILINGS PRODUCED FOR GOLD IN 2018

7

X 2 or 620 m


OPEN PIT DISPOSAL

8


DAMS PLUS TOPOGRAPHIC RELIEF

9


RING DAMS FOR FLATTER TERRAIN – OILSANDS 2016

10

Mildred Lake Tailings Pond18 km circumference

40 m (avg) to 88 m (max) high


THICKENED TAILINGS DISPOSAL

Ref.: Thickened Tailings Disposal at Xstrata Copper Canada, Kidd Metallurgical Site

Shiu Kam, David Yaschyshyn , Michael Patterson and David Scott11


PASTE TAILINGS – SURFACE & UNDERGROUND

12


FURTHER DEWATERING THROUGH DRY STACKING

13


CO-DISPOSAL OF TAILINGS WITH WASTE ROCK

14


PROGRESSION IN DEWATERING TECHNIQUES

15Ref.:Davies, M.P, & Lupo, J. & Martin, T. & McRoberts, E. & Musse, M. & Ritchie,

D., 2010, Dewatered Tailings Practice – Trends and Observations. In proceedings

of Tailings and Mine Waste ’10, Balkema.

Most filtered facilities ≤ 6,500 tpd

emphasis within arid climates


Dewatering Technology

Typical Processing & Transport Cost

($/t)

Typical Dam & Water

Management Cost ($/t)

Typical Total ($/t)

Range of Cost ($/t)

Relative Increase in Typical Total Compared to Conventional

Unthickened(conventional)

$0.20 $1.00 $1.20 $0.50 to $2.50 100%

Thickened $0.30 $1.00 $1.30 $0.50 to $2.50 110%

High density thickened

$0.50 $0.90 $1.50 $0.75 to $2.50 125%

Paste $1.50 $0.50 $2.00 $2.00 to $8.00 170%

Filtered $5.00 $0.20 $5.20 $4.00 to $12.00 430%

RANGE OF PROCESSING & INITIAL STORAGE COST

16

De

creasin

g Wate

r Co

nte

nt

Notes: 1. Costs are site and project specific and are indicative only

2. Cost per tonne typically decrease with increased tonnage due to economies of scale

3. Capital and closure costs not included.

“No universally ideal tailings dewatering technology or facility types…the ideal solution will depend on the

tailings properties, production scale, site characteristics, available technologies and facility types.”

Ref.: Mining Environment Neutral Drainage, October 2017


TAILINGS DAMS – FOUR MAIN APPROACHES

Embankment Construction

• Constructed to full height prior to deposition, likely under 1 contract/contractor

• Good permanent water storage suitability

• Any type of tailings

• Good seismic resistance

• Requires natural soil

• Relatively high embankment cost

17Ref: Vick, S.G. (1990). Planning, design, and analysis of tailings

dams. Vancouver, B.C.: BiTech Publishers Ltd., 369 pgs.

WATER

TAILINGS



Downstream Construction

• Constructed progressively using tailings, mine waste, or natural borrow materials

• Good permanent water storage suitability

• Any type of tailings

• Good seismic resistance

• Relatively high embankment cost (compared to centerline & upstream methods) spread over life of facility



TAILINGS



Centerline Construction


• Good temporary water storage ability

• Sands or low plasticity silts

• Acceptable seismic resistance

• Raising rate restrictions may apply

• Moderate embankment cost (less than downstream methods) spread over life of facility



TAILINGS



Upstream Construction


• Majority of all tailings dams worldwide

• Lowest embankment cost compared to above methods

• Sand requirements of 40% to 60%

• Not suitable for significant water storage

• Poor seismic resistance

• Raising rate restrictions of 15 -30 ft (4.6-9.1m) per year may apply



TAILINGS


TAILINGS DAMS’ RELATIVE EMBANKMENT VOLUMES

Upstream Construction

Centerline Construction

Downstream Construction

Area A1

Area A2 = 2A1

Area A3 = 3A1




GROWTH AND EVOLUTION WITH TIME – LL DAM 1988

97C

22

1988:

120 m tall

1,100 m Crest


GROWTH AND EVOLUTION WITH TIME – LL DAM 2010

97C

23

Circa 2010:

180 m tall

2,500 m Crest


GROWTH AND EVOLUTION WITH TIME – LL DAM 45 YEARS OLD

AND GROWING

Approx. footprint of 1988 structure

97C

24


TAILINGS DAMS ARE/CAN BE COMPLEX STRUCTURES

25

Water

Resources

Tailings

Dam

Versus

Ref.: ITRB Report on Mount Polley Tailings Storage Facility Breach, 30 January 2015


ACCIDENTS AND FAILURE EVENTS OVER TIME

26Ref.: Conclusions From Evaluation of Tailings Dam Incidents”, Strachan, C.,

and Van, R., USSD April 2018

≈10/YEAR ≈2/YEAR

3500 tailings operating dams in 2000• 1:1,000 Failure Frequency• 1:100 Event Frequency

By Comparison:For earthfill and rockfill dams in the U.S. constructed after 1960 (H 15 m to 90 m), estimated annual failure frequency is1:10,000 (Martin & Davies 2000)

• Greatest proportion of failures through Overtopping, Spillway, and Erosion


REPORTED CAUSE OF FAILURE

27Ref.: Conclusions From Evaluation of Tailings Dam Incidents”, Strachan, C.,

and Van, R., USSD April 2018


Samarco

Cadia

Brumandinho

Volume of Roman Colosseum

Channel Tunnel Excavation Volume

Volume of Olympic Swimming Pool

Mount Polley

1,000

10,000

100,000

1,000,000

10,000,000

100,000,000

1,000,000,000

1,000 10,000 100,000 1,000,000 10,000,000 100,000,000 1,000,000,000

Tail

ings

Re

leas

e V

olu

me

(m)

Tailings Storage Volume (m3)

VOLUME RELEASED VS STORED VOLUME

28Ref.: CIGB-ICOLD Bulletin No. 121 titled “Tailings Dams, Risks of Dangerous

Occurrences – Lessons Learnt from Practical Experiences” 2001, 146 pages.,

http://www.wise-uranium.org/mdaf.html


Mount Polley

Samarco

Cadia

Brumandinho

0.1

1

10

100

1000

1,000 10,000 100,000 1,000,000 10,000,000 100,000,000

Tail

ings

Tra

vel (

km)

Tailings Release Volume (m3)

Rio

Par

aop

eba

VOLUME RELEASED VS RUNOUT DISTANCE

29Ref.: CIGB-ICOLD Bulletin No. 121 titled “Tailings Dams, Risks of Dangerous




Ch

ile -

20

0 d

ead

or

mis

sin

g

Bu

lgar

ia -

48

8

Wal

es, U

K -

14

4

Zam

bia

-8

9

USA

-1

25

Sou

th A

fric

a -

12

Zim

bab

wa

-1

Jap

an -

1

USA

-1

Ital

y -

26

8

Ch

ina

-1

9

Ch

ina

-2

0

Per

u -

6

Sou

th A

fric

a -

17

- -P

hila

pin

es -

12

Ch

ina

-1

15

Bra

zil -

5

Ch

ina

-1

7

Ch

ina

-2

54

Ch

ina

-3

Hu

nga

ry -

10

Ru

ssia

-1

Bra

zil -

3

Bra

zil -

19

Mya

nm

ar -

11

5C

hin

a -

3M

exic

o -

7-

Bra

zil 2

70

- - - Mya

nm

ar -

57

-

-

50,000,000

100,000,000

150,000,000

200,000,000

250,000,000

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

30,000,000

35,000,000

40,000,000

45,000,000

50,000,000

31-D

ec-5

8

31-D

ec-6

0

31-D

ec-6

2

31-D

ec-6

4

31-D

ec-6

6

31-D

ec-6

8

31-D

ec-7

0

31-D

ec-7

2

31-D

ec-7

4

31-D

ec-7

6

31-D

ec-7

8

31-D

ec-8

0

31-D

ec-8

2

31-D

ec-8

4

31-D

ec-8

6

31-D

ec-8

8

31-D

ec-9

0

31-D

ec-9

2

31-D

ec-9

4

31-D

ec-9

6

31-D

ec-9

8

31-D

ec-0

0

31-D

ec-0

2

31-D

ec-0

4

31-D

ec-0

6

31-D

ec-0

8

31-D

ec-1

0

31-D

ec-1

2

31-D

ec-1

4

31-D

ec-1

6

31-D

ec-1

8

Cu

mu

lati

ve V

olu

me

Re

leas

ed

(m

3)

Vo

lum

e R

ele

ase

d P

er

Inci

de

nt

(m3

)

Date

Reported Volume Released Per Incident

Cumulative Reported Volume Released

>2,280 Reported Dead or Missing

Ref.: CIGB-ICOLD Bulletin No. 121 titled “Tailings Dams, Risks of Dangerous



EVENT AND CUMULATIVE VOLUME AND LIVES LOST

30


31

MOUNT POLLEY 4 AUG 2014

Ref.: ITRB Report on Mount Polley Tailings Storage Facility Breach, 30 January 2015


MOUNT POLLEY 4 AUG 2014 - VIDEO

32Ref.: ITRB Report on Mount Polley Tailings Storage Facility Breach, 30 January 2015


MOUNT POLLEY - LAYOUT AND CROSS-SECTIONS



MOUNT POLLEY - IMAGES SUPPORTING FOUNDATION FAILURE



MOUNT POLLEY TAILINGS TRAVEL DISTANCE

≈22 km from breach

36


MOUNT POLLEY EXPERT PANEL FINDINGS

“The design did not take into account

the complexity of the sub-glacial and

pre-glacial geological environment

associated with the Perimeter

Embankment foundation. As a result,

foundation investigations and

associated site characterization failed

to identify a continuous

Glaciolacustrine (GLU) layer in the

vicinity of the breach and to recognize

that it was susceptible to undrained

failure when subject to the stresses

associated with the embankment.”



SAMARCO FUNDÃO TAILINGS DAM FAILURE 5 NOV 2015

38Ref.: Fundao Talings Dam Review Panel Report on the Immediate Causes of the

Failure of the Fundao Dam, 25 August 2016,

https://blogs.agu.org/landslideblog/2015/11/08/samarco-1/

Ref.: Fundão Talings Dam Review Panel Report on the Immediate Causes of the

Failure of the Fundão Dam, 25 August 2016,


FUNDÃO TSF – APRIL 2005

39

SANTAREM DAM AND RESERVOIR

GERMANO TSF GERMANO

DAM

SELA DYKE

TULIPA DYKE

FUTUREFUNDÃO TSF


FUNDÃO TSF DESIGN INTENT

40

SLIMES

SAND TAILINGS

Sand Tailings (70%)40% to 60% fine sand, 40% to 60% Silt,


FUNDÃO TSF SAND TO SLIMES RATIO

24% 25%

64%

48%

67%63%

58%

65%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

-

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

8,000,000

9,000,000

2008 2009 2010 2011 2012 2013 2014 2015

PER

CEN

TAG

E O

F SA

ND

TA

ILIN

GS

VO

LUM

E O

F SA

ND

OR

SLI

MES

(M

3)

YEAR

Sand Tailings Dyke 1 Reservoir

Slimes Dyke 1 Reservoir, Sand and Slimes Dyke 2 Reservoir

Percentage of Sand in Dyke 1 Reservoir to Total Tailings

DESIGN INTENT 70% SAND, 30% SLIMES

Ref.: Fundão Talings Dam Review Panel Report on the Immediate Causes of the Failure of

the Fundão Dam, 25 August 2016., Federal Public Service, MJ-Federal Police Regional

Superintendents in the State of Minas Gerais, Technical Scientific Sector (2016). Report No.

994/2016 – SETEC/SR/PF/MG – Federal Forensic Report (Engineering).


FUNDÃO TSF – SEPT 2011

42

FUNDÃO DAM (DYKE 1)

DYKE 2

FUNDÃO TSF


GERMANO TSF GERMANO

DAM

SELA DYKE

TULIPA DYKE

SELINHA DYKE


FUNDÃO TSF – MAY 2013

43


DYKE 2

FUNDÃO TSF


GERMANO TSF GERMANO

DAM

SELA DYKE

TULIPA DYKE

SELINHA DYKE


FUNDÃO TSF – AUG 2014

44


DYKE 2BURIED

FUNDÃO TSF


GERMANO TSF GERMANO

DAM

SELA DYKE

TULIPA DYKE

SELINHA DYKE


FUNDÃO TSF – JULY 2015

45


FUNDÃO TSF


GERMANO TSF GERMANO

DAM

SELA DYKE

TULIPA DYKE

SELINHA DYKE

DYKE 2BURIED


FUNDÃO TSF ELEVATION VIEW OCT 2015

46

Right Abutment

Left Abutment

Initial then Second Setback

Dyke 1 Starter Dyke

Dyke 2 (covered)

Ref.: www.mining.com/why-samarco-tailings-dam-failed/


FUNDÃO TSF DYKE 1 FAILURE – APRIL 2009

• Failure 4 months following sand tailings

deposition, ± 10 month following slimes

deposition

• Dyke 1A constructed u/s to investigate

• Gross construction defects with respect

to foundation drains

• Foundation drains abandoned

• Replaced with blanket drain at El. 826 m

Ref.: Fundão Talings Dam Review Panel Report on the Immediate Causes of the Failure

of the Fundão Dam, 25 August 2016., Federal Public Service, MJ-Federal Police Regional

Superintendents in the State of Minas Gerais, Technical Scientific Sector (2016). Report

No. 994/2016 – SETEC/SR/PF/MG – Federal Forensic Report (Engineering).


FUNDÃO TSF DYKE 1A – SLIMES WITHIN DYKE 1 RESERVOIR






FUNDÃO TSF FAILURE OF DRAINAGE GALLERIES

Secondary Gallery November 2012Primary Gallery July 2010






FUNDÃO TSF SLIMES MIGRATION

Overflow Channel Operational

Period:

▪ February 2011 – July 2012

(18 Months)

▪ July 2013 – December 2013

(6 Months)

50

Crest of Fundão Dam Oct 2015

Former Dyke 1A

Overflow Channel – Slimes from Dyke 2 to Dyke 1 Reservoir





Designed and constructed alignment up to ~El. 855m

Actual dam alignment at the DOL

Projected designed alignment on El. 900m

Former Dyke 1A

Limits of Blanket Drain

Slimes Retained By Dyke 1A

Slimes From Overflow Channel

January 2012

March 2012

September 2011





Design Water Table

Range of Actual Water Tables Interpreted From Piezometers




53

FUNDÃO TSF FROM RIGHT ABUTMENT NOV 2015




FUNDÃO TSF FROM RIGHT ABUTMENT POST FAILURE

54Ref.: www.theguardian.com/world/2018/


FUNDÃO TSF FROM LEFT ABUTMENT PRE & DURING FAILURE

55




FUNDÃO TSF FAILURE ORIGINATING FROM LEFT ABUTMENT -

VIDEO

56



Reduction in

Confining Stress on

Loose, Saturated

Contractive

Tailings….Causing

Collapse


FUNDÃO TSF DOWNSTREAM IMPACT

57Ref.: https://blogs.agu.org/landslideblog/2015/11/08/samarco-1/,

https://www.unenvironment.org/news-and-stories/story/dam-or-be-damned-mining-

safety-under-scrutiny


FUNDÃO TSF DOWNSTREAM IMPACT – SANTAREM DAM

Before After

58


FUNDÃO TSF BENTO RODRIGUES - 7 KM D/S - VIDEO

00:01:07

00:03:40

00:05:40

00:00:00

?


FUNDÃO TSF TAILINGS TRAVEL DISTANCE

60

November 22, 2015

650 KM IN 17 DAYS

• 35 Mm3 of Tailings Evacuated

• 20 Mm3 of Tailings Remained

• 19 Lives Lost

• 600 People Displaced

• Samarco’s Operations Suspended Now

For 3 Years (PD $MM, BI $B)

• 22 Criminal Indictments


NEWCREST CADIA VALLEY OPERATIONS 9 MAR 2018

• NTSF PRIOR TO FAILURE

• 91 m maximum embankment

height

• 3,900 m crest length

• 9 m crest width

• 450 ha area

• 160 Mm3 tailings stored

• 170 Mm3 tailings capacity

61Ref.: Newcrest Market Release 12 March 2018, 27 March 2018, 3 April 2018


CADIA NTSF REPORTED EVENTS PRIOR TO FAILURE

8 March 2018:• M2.7 Earthquake occurred

9 March 2018:• Cracking (morning), then

embankment slumped (19:00)

• Tailings deposition stopped

10 March 2018:• Suspension of all mining and

processing operations

• Geotechnical monitoring including radar and cameras established

“Prior to slump”• Relocated residents of 2 houses

• Briefed landholders below tailings dams and requested restricted access

62Ref.: Newcrest Market Release 12 March 2018, 27 March 2018, 3 April 2018


CADIA NTSF FAILURE DIMENSIONS AND CONTAINMENT

63

Dimensions Reported/Estimated:

• ≈ 270 m wide

• ≈ 60 to 90 m high

• ≈ 100 m u/s

• ≈ 200 m d/s

• ≈ 1.3 Mm3 of soil

• Limited flow liquefaction propagation

• Construction of 2 km of containment

bunds/berms

• Mining resumed 17 days after

slump, processing resumed 22 days

after slump

Ref.: Ref.: Newcrest Market Release 12 March 2018, 27 March 2018, 3 April 2018,

www.mining-journal.com/research/news/1316689/cadia-tailings-dam-failure-to-hit-

guidance


CADIA NTSF AND STSF JUNE 2016

64

Pond located away from future failure

Location of Failure


CADIA NTSF PRECURSOR DEFORMATION (DEC 2017 to MAR 2018)


!!

CADIA NTSF PRECURSOR DEFORMATION (DEC 2017 to MAR 2018)

December

2017


CADIA NTSF PRECURSOR DEFORMATION (9 MAR 2018)

67Ref.: Independent Technical Review Board Report on NTSF Embankment Failure,

Cadia Valley Operations for Ashurst Australia


CADIA NTSF POST FAILURE 9 MAR 2018




CADIA NTSF POST FAILURE 9 MAR 2018

69

Progressive upstream construction from starter ring dyke

Ref.: www.mining-journal.com/research/news/1316689/cadia-tailings-

dam-failure-to-hit-guidance

Starter dyke material has displaced and partially raveled

downslope

Tailings initially contained by slumped starter dyke material

Horizontal lips reflect previous upstream

constructed lifts from starter dyke or upstream raises


CADIA NTSF CROSS-SECTION

70

1998-2000

Ref.: Independent Technical Review Board Report on NTSF Embankment Failure,


2005-2016

2016-Dec 20172000-2005


CADIA NTSF CROSS-SECTION

71

Dec 2017-Failure

Stage 10 Completed in Area of Collapse by 31 July 2017

Buttress 1 Installed In Area of Collapse 15 Dec 2017 to 5 March

2018 – 4 days before failure

Buttress 2 Not Installed In Area of Collapse Prior to Failure

2007 Initiated Buttress Not Installed

in Area of Collapse

Estimated Toe Excavation in Area of Collapse in January

2018 and Left Open

Ref.: Independent Technical Review Board Report on NTSF Embankment Failure,



1. Progressive failure in the foundation soils as upstream raises cause outward horizontal movement in the foundation.

2. Foundation movements reduce the lateral support to the tailings while increasing yielding (deformation) in the tailings.

3. When yielding in the tailings progresses to the instability locus or point of collapse, the tailings behavior reverts from a drained to an undrained strength, causing a rapid approximately 2/3rds reduction in their strength.

4. The loss of strength in the loose saturated tailings due to their liquefaction resulted in a further increase in the lateral load to the dam wall, causing accelerated and larger scale movements.

ITRB REPORT ON NTSF FAILURE




BRUMANDINHO - CÓRREGO DE FEIJÃO – DAM 1

73


CÓRREGO DE FEIJÃO – DAM 1

74Ref. TÜV-Süd Periodic Dam Safety Review Technical Report, Ref. SP-RC-117/17,

265 pages

• Initial Starter Dyke 18 m high constructed in 1976

• Ten (10) upstream lifts in various stages, reaching a height of 86 m by 2013

• Stopped receiving tailings in 2016

• Undergoing reclamation at time of failure

• Failure on 25 January 2019



75

Da Silva, W. P., Gomes, R.C., 2013. Tailings Liquefaction Analysis Using Strength Ratios

and SPT/CPT Results. ABMS – Brazilian Association for Soil Mechanics and

Geotechnical Engineering, SPG – Portuguese Geotechnical Society, Vol. 36, No. 1,

January – April 2013, pgs. 37- 53.

• Initial 2013

?

?

??

Interpreted Contractive (Liquefiable) Tailings

Interpreted Dilative (Non-Liquefiable) Tailings


CÓRREGO DE FEIJÃO – DAM 1 – 25 JAN 2019 - VIDEO

76

12:28:23

12:28:29

12:28:37

12:28:55


BRAZIL CUIABÁ METROPOLITAN REGION - 1 OCT 2019

79Ref.:https://blogs.agu.org/landslideblog/2019/10/04/nosso-senhora-do-livramento-tailings/


BRAZIL CUIABÁ METROPOLITAN REGION - 1 OCT 2019

80Ref. https://www.issoenoticia.com.br/post/barragem-de-mineracao-se-rompe-na-

regiao-metropolitana-de-cuiaba-veja-fotos-e-video


RUSSIAN MINING DAM FAILURE - 19 OCT 2019

• “At least 15 people have died and 13 others are missing after a dam collapse at a gold mine in Siberia.”

• The dam, on the Seiba river in the region of Krasnoyarsk, burst after heavy rain on Saturday, flooding cabins where workers lived.

• "The hydro-technical facility was self-constructed and, I believe, all rules I can and cannot think of were violated," Yuri Lapshin, the head of the Krasnoyarsk regional government, was quoted by RIA news agency as saying.

81Ref.:https://www.bbc.com/news/world-europe-50108413


Canadian Dam Association (CDA)▪ CDA Dam Safety Guidelines

Mining Association of Canada (MAC)▪ A Guide to the Management of Tailings Facilities

International Congress on Large Dams (ICOLD)▪ Bulletins Specific to Tailings and TSF: 44A, 45, 74, 97, 98, 101, 103, 104, 106, 121,

139, 159

Australian National Committee on Large Dams (ANCOLD)▪ ANCOLD Guidelines on Tailings Dams

European Commission▪ BAT for Management of Tailings and Waste-Rock in Mining Activities

South African National Standards (SANS)▪ SANS Code of Practice – Mine Residue

US Federal Emergency Management Agency (FEMA) & US Army Corp of Engineers (USACE)

LEADING INTERNATIONAL STANDARDS & GUIDELINES

82


ICMM COMMISSIONED REPORT (2016) FOUND:

• Best of currently available national and international guidance documents all provide excellent good practice guidance and provide foundation for good practice in company guidance documents.

• Based upon the three recent failures, they concluded that:

…if one were to focus on these and other such case histories through consideration of a greater number of failures and investigation results over the last 20 or so years, and ask the question is there anything missing from existing standards and guidance documentation that if known and applied could have forestalled such events, then the answer might be as follows:

Existing published guidance and standards documentation fully embrace the knowledge required to prevent such failures. The shortcoming lies not in the state of knowledge, but rather in the efficacy with which that knowledge is applied. Therefore, efforts moving forward should focus on improved implementation and verification of controls, rather than restatement of them.

INTERNATIONAL COUNCIL ON MINING AND METALS (ICMM)

83Ref.: https://www.icmm.com/tailings-report


ICMM 2016 POSITION STATEMENT

10 Guiding Principals For Preventing Catastrophic TSF Failures, with the following Commitments:

• Accountabilities, responsibilities and associated competencies are defined to support appropriate identification and management of tailings storage facilities risk.

• The financial and human resources needed to supportcontinued tailings storage facility management and governance are maintained throughout a facility’s life cycle.

• Risk management associated with tailings storage facilities, including risk identification, an appropriate control regime and the verification of control performance.

• Risks associated with potential changes are assessed, controlled and communicated to avoid inadvertently compromising facility integrity.

• Processes are in place to recognize and respond to impending failure of facilities and mitigate the potential impacts arising from a potentially catastrophic failure.

• Internal and external review and assurance processes are in place so that controls for facilities risks can be comprehensively assessed and continually improved.

84https://www.icmm.com/tailings-ps, https://mining.ca/our-focus/tailings-management/tailings-guide/

December 2016


MINING ASSOCIATION OF CANADA (MAC) TSF GUIDELINES 2017

Third Edition Included New Guiding Principals:

• Risk-Based Approach for managing physical and chemical stability considering:

• Rigorous risk assessment and transparent decision making

• Best Available Technologies (BAT)

• Best Available Processes (BAP)

• Critical Controls for identification, implementation and performance monitoring to manage high-consequence risks

• Engineer of Record (EOR) with the owner having responsibility to identify and retain for design, construction and performance monitoring throughout lifecycle

• Objective independent third-party independent review on behalf of owner of all aspects from planning, design, construction, operation, maintenance

“This new Guide provides an outstanding document to influence the organization and governance protocols needed to ensure safe tailings management from the conceptual stages through to closure.” (Morgenstern 2018)

9 September 2019: Brazil Instituto Brasileiro de Mineração (IBRAM), announced that it will adopt the Towards Sustainable Mining (TSM) initiative, a corporate social responsibility program developed by the Mining Association of Canada (MAC). IBRAM joins six other mining associationsaround the world, including the second in Latin America, in adopting TSM, an increasingly internationally recognized standard for responsible mining.

85Ref.:https://mining.ca/our-focus/tailings-management/tailings-guide/,

https://mining.ca/press-releases/brazil-adopts-canadas-towards-sustainable-mining-

initiative/, https://www.icmm.com/tailings-report

https://mining.ca/press-releases/brazil-adopts-canadas-towards-sustainable-mining-initiative/https://www.icmm.com/tailings-report


27 March 2019:

ICMM, UN Environment Programme and Principles for Responsible Investment Agree to Co-convene Mine Tailings Storage Facilities Review

London, UK – The International Council on Mining & Metals (ICMM), the United Nations Environment Programme (UNEP) and the Principles for Responsible Investment (PRI), today announced that they will co-convene an independent review that will establish an international standard on tailings storage facilities.

While the standard would become an ICMM company member commitment, the co-convening partners will encourage others to join in advocating for it to be accepted more broadly.

This initiative is in response to the recent tragedy at Brumadinho and will be informed by evidence and lessons from earlier mine tailings dam failures. The aim is to complete this work by the end of the year.

The PRI will be represented by the Church of England Pensions Board and the Council of Ethics of the Swedish National Pension Funds, who are both PRI signatories.

As a next step the co-convenors will jointly appoint an independent chair and a multi-stakeholder advisory panel. There will be a further update once the chair has been appointed.

ICMM, UN AND PRI PENDING GUIDELINES

86https://www.icmm.com/en-gb/news/2019/tailings-review


“To this end, it is recommended for any specific project that the operator be required to develop, for regulatory approval and subsequent execution, a tailings management system for Performance-Based, Risk-Informed Safe Design Construction Operation and Closure of the proposed tailings storage facility (PBRISD). Many single elements combined in PBRISD have been identified before, but the required integration presented in the following is perceived as necessary to impose more rigorous direction, supported by critical levels of review at various stages of the process.”

• Stage 1 (Conceptual) involving a qualified operator, established independent review board, uncertainty assessment, potential problem analysis (PPA), and multiple account analysis (MAA)

• Stage 2 (Feasibility) involving engineer of record (EOR), designer, design basis memorandum (DBM), risk assessment, quality management, documentation

• Stage 3 (Construction and Operation) involving safe construction and operations dictated by the operation, maintenance and surveillance manual (OMS)

• Stage 4 (Closure) planning considered during all previous stages, with increasing levels of detail with time

“Instead, the underlying principle for the tailings management system advocated here (PBRISD) is accountability. This is achieved by multiple layers of review, recurrent risk assessment, and performance-based validation from construction through closure.”

TOWARDS ZERO FAILURES (Morgenstern 2018)

87Ref.: Morgenstern, 2018, Geotechnical Risk, Regulation and Public Policy,

The Sixth Victor de Mello Lecture, 9th Portuguese –Brazilian Geotechnical Congress

Salvador, Bahia, Brazil, 30 August 2018.


SOME FINAL COMMENTS

• Major failure rates of 2 events/year unlikely to lessen in short term

• Various innovations in dewatering and storage of tailings reducing risk of collapse and downstream consequences (mobility)

• Lessons are being learned from major failures such as Mount Polley, Samarco, Cadia, and Feijão (technically, operationally and managerially – reduce risks and consequences)

• Available national and international guidance documents provide excellent good practice guidance in design, construction, operation, and closure

• Guidelines being upgraded with support of ICMM, UN, and PRI, which are being informed based upon Performance-Based, Risk-Informed Safe Design Construction Operation and Closure

• “Tailings dams are complex systems that have evolved over the years. They are also unforgiving systems, in terms of the number of things that have to go right. Their reliability is contingent on consistently flawless execution from concept to completion.” (Mount Polley Expert Panel Report)

88


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tailings storage facilities insights - types, failures, tailings … · 2020. 12. 17. · tailings...

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