2. Dr. Gavin Mudd
Associate Professor at RMIT
University
Duane Thompson
Head of Water
MINETEK
Nick Deeks
GHD | BE (Civil & Environmental)
Technical Director - Hydrology
Lourenço Mendonça
Technical Sales Water
MINETEK, Brazil
OUR SPEAKERS

3. “THERE HAS BEEN
A STAGGERING RISE
IN THE NUMBER OF
EXTREME WEATHER
EVENTS OVER THE
PAST 20 YEARS.”
YALE ENVIRONMENT 360,
REPORTING ON A STUDY FROM
THE UNITED NATIONS.

4. The information presented in the following graphs is from a
publication called “The human cost of disasters: an overview of
the last 20 years.” By the Centre for Research on the
Epidemiology of Disasters, the United Nations Office for Disaster
Risk Reduction (UNDRR.)
Major disasters: 4,212 compared to 7,348.
These are disasters which have killed ten or more people; affected
100 or more people; resulted in a declared state of emergency, or a
call for international assistance.
Deaths per million: 1.19 million lives compared to
1.23 million lives
People affected per billion: 3.25 billion compared to
4.2 billion people (many on more than one occasion.)
The global economic loss from disaster: Disaster has cost us
US$1.19 trillion in economic losses compared to $2.97 trillion.
What can explain the sharp increase?
Much of the difference is explained by a rise in climate-related
disasters including extreme weather events: from 3,656
climate-related events (1980-1999) to 6,681 climate-related
disasters in the period (2000-2019).
The last twenty years have seen the number of major floods
more than double, from 1,389 to 3,254, while the incidence of
storms grew from 1,457 to 2,034.
Floods and storms were the most prevalent events.

5. THE HUMAN COST OF DISASTERS
5
4212
7348
0
1000
2000
3000
4000
5000
6000
7000
8000
MAJOR DISASTERS
1.19
1.23
1.17
1.18
1.19
1.2
1.21
1.22
1.23
1.24
DEATHS
PER MILLION
3.25
4.2
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
AFFECTED PER
BILLION
1.63
2.97
0
0.5
1
1.5
2
2.5
3
3.5
GLOBAL COST
PER TRILLION
1980-99 2000 - 19

6. THE RISE IN EXTREME WEATHER EVENTS
6
3656
6681
0
1000
2000
3000
4000
5000
6000
7000
8000
CLIMATE & EXTREME
WEATHER EVENTS
1389
3254
0
500
1000
1500
2000
2500
3000
3500
MAJOR FLOODS
1457
2034
0
500
1000
1500
2000
2500
STORMS
1980-99 2000 - 19

7. “FLOODS AND
STORMS ARE
THE MOST
PREVALENT
EVENTS.”
CENTRE FOR RESEARCH ON THE
EPIDEMIOLOGY OF DISASTERS, UNITED
NATIONS OFFICE FOR DISASTER RISK
REDUCTION.
While a rise in other areas including
drought, wildfires, extreme temperatures
and earthquakes has also been noted –
Floods and storm events were the most
prevalent.
This trend needs to be considered when
approaching mine water management.
How do you plan for this increase,
and how can we mitigate risk?

8. UNDERSTANDING TAILINGS
DAM DISASTERS
PRESENTED BY DR. GAVIN MUDD

9. Mining is both a large consumer of water as well as a large producer of
water. Dr. Gavin Mudd has been working in the space of quantifying the
footprint of mining for many years.
MINING NOW GENERATES
~9 BILLION TONNES OF TAILINGS ANNUALLY
We need to consider both the quantity (ie. Hydrology - flood risks) and
quality (the chemistry - pollution) of tailings dams when looking at mine
water management. In Australia many mines have to deal with pollution
risks or flood risks, and often both.
It’s important to not cause another problem by only considering one of
these issues in mine water management strategies.
Recent major mining-related disasters around the world have turned
attention to the links between mine water management and tailings dam
safety and related issues.
MINING DISASTERS & THE IMPORTANCE OF WATER

10. 10
In the last 10 years we have seen an increase in
accidents in mining.
These articles are two examples from more than 5
years ago. Even before the major dam collapses
most people know (in Brumadinho and Minas
Gerais) we’ve had some big floods effecting many
areas of mines in Australia.
Hunter Valley, Bowen Basin, Mount Morgan Mine to
name a few. Many flood risk mines are near national
parks or places of cultural significance.
We need to consider a solution. These cases should
make us stop and think about better solutions.
Engineering, monitoring hydrological estimates and
maintenance and monitoring and especially the
management systems we have in place.
EXAMPLES OF DISASTERS IN AUSTRALIA

11. 11
SOME TSF MODES: THE IMPORTANCE OF WATER
RAPID WATER RISE
DYNAMIC LIQUEFACTION
PIPING
OVERTOPPING
These graphics of common tailings dam failure modes come from the WISE Uranium Project, which includes the only independent synthesis
of information on tailings dam failures. The most common causes of tailings dam failures include over-topping, foundation failure,
static or dynamic liquefaction, piping or wall failure.

12. THE MOST COMMON FAILURES OF TAILINGS
DAMS COME BACK TO WATER.
BUDGET, BALANCE AND WATER QUALITY.

13. 13
COUNT BY SEVERITY CODE COUNT BY SEVERITY INDICATORS
DECADE
VERY SERIOUS
FAILURES
SERIOUS
FAILURES
MINOR FAILURES
POTENTIAL
FAILURE
CONDITION
ALL FAILURES
POTENTIAL
FAILURES
CUMULTIVE
RELEASE
CUMULATIVE
RUNOUT (KM)
DEATHS
1 2 3 4 Count M Cub m Km Count
2010-2019 12 14 19 0 45 102.7 859.6 486
2000-2009 12 11 12 1 36 14.1 292.3 342
1990-1999 12 12 25 3 52 68.2 169.2 72
1980-1989 6 8 31 3 48 103.1 48.9 316
1970-1979 7 8 16 1 32 24.7 284 838
1960-1969 8 4 21 2 35 19.6 59 1050
1950-1959 8 2 3 0 13 19.3 51.1 303
Total/ Average 55 63 95 10 233 155 845 2004
DAM FAILURES BY DECADE (1915-2020)
This information comes from “world mine tailings failtures.org,” which sources Dr. Gavin Mudd’s work, including a world waste survey for the
joint study groups, UNEP’s 2019 and Geo6.
This data shows that we haven’t improved in any aspects of dam failures.
Based on available compilations an apparent 43-50% of all existing tailings are in “high hazard potential” TSFs and that percentage is not
expected to change over the next 5 years with over 90% of all new depositions going to already existing standard above ground storage
facilities.

14. 14
THE TAILINGS DAM LANDSCAPE
The world’s 29,000-35,000 {1} existing active, inactive and abandoned tailings storage facilities (TSF) contain approximately 223 billion tonnes (534
billion cubic meters.) The increasing volumes of total waste to product is directly attributable to the mining of ever lower grades across all minerals.
This does NOT mean we are “running out” – it simply means geology, technology, economics coincide to keep mining (mostly) profitable.
But there are more tailings per unit metal / mineral. - Quote & graphs from worldminetailingsfailures.org

15. 15
TREND OF INCREASING FREQUENCY
AND SEVERITY OF FAILURES
“THIS IS THE CHALLENGE. THIS IS
WHAT WE HAVE TO RESPOND TO.
NOT JUST THE NUMBER OF FAILURES,
BUT ALSO THE CHARACTERISTICS, IN
TERMS OF THE SEVERITY AS WELL.
HOW DO WE TALK ABOUT DERISKING
OUR TAILINGS DAMS TO ACHIEVE OUR
SAFETY GOALS? I THINK THAT’S A
REALLY IMPORTANT POINT.”
- Dr. Gavin Mudd

16. The previous data is some of the only work on gathering tailings
dam failures, noting important factors that make up these disasters.
We need to understand the volume of waste, where it is, how it’s
being managed and if there is a disaster.
Where are the tailings, and what are the risks.
We have not been asking these questions as rigorously as we
should.
Looking at the data; the number of instances relative to the number
of tailings, it shows is that there is an increasing trend.
The data collected shows an upwards trend in disasters.
What this suggests is that our efforts in managing mine waste are
not keeping up with the scale of mine water.
We need to learn how to get better outcomes and mine water
management plays a large role in this.
“WHAT THIS
SUGGESTS, IS THAT
OUR EFFORTS IN
MANAGING MINE
WASTE ARE NOT
KEEPING UP
WITH THE SCALE OF
MINE WATER.”

17. THE NUMBER OF
TAILINGS DAM
FAILURES HAS
DOUBLED IN THE
PAST 20 YEARS.
WHY HAVE SO MANY TAILINGS DAMS
FAILED IN RECENT YEARS? EMAP
SCHOOL OF APPLIED MATHEMATICS,
FUNDACAO GETULIO VARGAS, RIO DE
JANEIRO, BRAZIL
The most important question is “why?”
Once we know why things fail, we can come up with solutions.
To quote Albert Einstein, You can’t solve a problem with the same thinking
that created it. Therefore, we need to make sure we understand our water,
climate, and weather event risk.
If the airline industry had this same outcome with flying, no one would be
flying at all. If we take that industry as an example, we have a lot more
flights, a lot more people, however their safety record is going up. It’s a
great example that says, Yes, we can achieve great goals in safety.
This safety thinking is not something that’s unusual in mining. From
occupational health and safety in mining to process mining. Many
departments already think strategically about safety outcomes.
We need to think about how we can apply this same kind of rigorous safety
thinking to our tailings dams, so that in another 20 years time, instead of
accidents doubling, we’ve reduced that number.
By 2050: Get our target down to zero.
Hopefully, that’s a target we can all get on board with.

18. THE RESULTS
OF DAM COLLAPSE

19. WORST CASE SCENARIO
When things go wrong with a tailings dam, we aren’t looking at something
small like a pause in operation.
When things go wrong, they can go horribly wrong.
We need to get better at thinking What will happen if things do go wrong?
We need to fix these ‘what if’ things first, before going to market.
We know tailings dams can kill people, cause extreme environmental
impacts and more. We need to make sure we are asking these questions.
There are also multi-million-dollar costs.
Regulation, and independent regulators are one of the key processes for
success. We need to make sure we are having these independent checks.
At the site of the Brumadinho disaster, they were compliant with the legal
obligations, but those criteria weren’t good enough.
We have to start asking these same questions across every tailings dam and
water storage facility.
Before we install a new tailings dam, we have to ask ourselves “What
could go wrong.” “What can we do to mitigate these risks.”
We need to not only get the engineering right, but regulations right, and
the funding right, which is something not often talked about in these
conversations.
BRUMADINHO DAM COLLAPSE

20. 270 LIVES LOST
$7 BILLION PAYOUT THE LARGEST
SETTLEMENT
IN BRAZILIAN LEGAL HISTORY.
$3.7 BILLION ADDITIONAL
EXPENSES IN VALE’S 2020 RESULTS.
HOMICIDE CHARGES FILE FOR 16
PEOPLE INCLUDING THE FORMER
CHIEF EXECUTIVE.
BRUMADINHO DAM COLLAPSE

21. DROP IN SHARES IMMEDIATELY AFTER THE DISASTER.
ONGOING FALLOUT WITH REGULATORS, COMMUNITY AND
INVESTORS. ADDITIONAL LAWSUITS BETWEEN MINERS
AND LOCALS. ASSESSMENT AND EVACUATION OF 3
OTHER SITES. PLANS TO IDENTIFY AND DISMANTLE 30
OTHER STRUCTURES BUILT THE SAME WAY AS
BRUMADINHO. ONGOING ENVIRONMENTAL AND TOURISM
DAMAGE. AND MORE…
BRUMADINHO DAM COLLAPSE

22. WHY HAVE SO MANY TAILINGS DAMS FAILED IN RECENT YEARS?
EMAP SCHOOL OF APPLIED MATHEMATICS, FUNDACAO GETULIO
VARGAS, RIO DE JANEIRO, BRAZIL
INCREASES IN PRODUCTION PUTS PRESSURE ON TAILINGS
FACILITIES.
PRODUCTION INCREASED AT LOS FRAILES, MT POLLEY, SAMARCO
AND BRUMADINHO BEFORE THE TAILINGS DAM FAILURES.
COMPENSATION PACKAGES FOR MET OR EXCEEDED KPI’S OFTEN
ENCOURAGE MANAGERS TO TAKE RISKS.

23. CLICK TO WATCH
THE FULL WEBINAR
ON DEMAND.

24. 1. The human cost of disasters: an overview of the last 20 years (2000-2019) | UNDRR
2. Extreme Weather Events Have Increased Significantly in the Last 20 Years - Yale E360
3. 3 - Changes in Climate Extremes and their Impacts on the Natural Physical Environment (ipcc.ch)
4. World Mine Tailings Failures—from 1915 – supporting global research in tailings failure root cause, loss prevention and trend analysis
5. Why have so many tailings dams failed in recent years? – ScienceDirect
6. Vale Agrees to $7 Billion Settlement for Brumadinho Dam Collapse – WSJ
7. Brazil court accepts homicide charges over dam disaster | News | DW | 15.02.2020
SOURCES

25. THANK YOU