The role of the human factor in mine accidents is not often well understood or adequately addressed. This presentation details the psychology and biases in human decision making in the face of complex mine stability problems.

2. Anatomy of Mine Failures
The Human Factor and the
Lessons
Tim Sullivan
DPI | Inaugural Mining Managers Safety Conference | 3.11.20192

3. Outline of Presentation
The role of the human factor in mine accidents is not often well understood or
adequately addressed.
The presentation covers in detail the psychology and biases in human decision
making in the face of complex mine stability problems.
The focus is on the anatomy of failures, critically examines the technical advice given
to senior mine management and their responses to those messages.
Deals with mine stability problems with large economic cost, significant injury and
fatality.
The common elements are examined, the contributing factors and causes are
highlighted and examined, including, management and corporate decision
making, cognitive dissonance, critical safety decision making and history.
The important lessons from are highlighted to provide guidance in decision making.
DPI | Inaugural Mining Managers Safety Conference | 3.11.20193

4. Lesson from Other General Australian
Engineering Experience
Canberra Hospital, HMAS Westralia and Longford.
Three factors:
Lack of technical expertise,
Inadequate engineering practice,
Failure to adequately assess competencies.
All were ‘system failures’,
Involving many players and
Many factors involved.
All these factors could equally apply equally to the examples I will
present here today.
DPI | Inaugural Mining Managers Safety Conference | 3.11.20194

5. Decision Error
Theory
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6. Decision Error Theory
All decisions contributing to an accident scenario fall into three mutually
exclusive error classes:
1. Errors of Commission.
2. Errors of Omission.
3. Errors of Mistaken Belief.
DPI | Inaugural Mining Managers Safety Conference | 3.11.20196

7. Errors of Commission
Errors made by a person who is:
Fully cognisant that a standard or rule or norm applies to a
situation,
But transgresses that standard,
For reasons generally known only to themselves, but
usually due to misplaced priorities,
Often associated with senior personnel in a position of
power or authority,
Knowledgeable and experienced,
But who believe they have discretion based on their
appraisal of the situation.
DPI | Inaugural Mining Managers Safety Conference | 3.11.20197

8. Errors of Omission
Errors made by a person who is:
Fully cognisant that a standard or rule or norm applies to
a situation,
But defers complying with the standard until it is too late.
Often attributed to:
Human factors such as fatigue, panic,
disorientation or fear; and or
Environmental factors such as heat, noise,
humidity; and or
Transgresses the standard due to competing
priorities.
Often associated with personnel in situations that are degrading
with time, they feel unable to cope or compensate.
DPI | Inaugural Mining Managers Safety Conference | 3.11.20198

9. Errors of Mistaken Belief
Errors made by a person who either:
Doesn’t know that a standard, rule or norm applies;
Or is aware of the standard,
But makes a decision(s) based on incorrect assumptions or
assessment of the real situation.
Sometimes associated with personnel who have inadequate training,
or lack of cognitive processing skills to make the correct
decision;
Or functioning in a job setting that is beyond their level of
competence.
It is my experience this is the most common reason why failures continue to
occur.
DPI | Inaugural Mining Managers Safety Conference | 3.11.20199

10. Mine Accidents and
Failures
DPI | Inaugural Mining Managers Safety Conference | 3.11.201910

11. Mine Accidents
The experience shows many large mine accidents:
Comprise decisions made over a considerable period
of time,
By all of the workplace parties,
Not just those associated with day to day operations,
Also includes corporate management,
All adversely affected by cognitive dissonance, and
Sometimes including the Regulator.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201911

12. Some Contributing Corporation Factors
A risk taking corporate culture.
An organisation that has become conditioned (immune) to risk.
Inadequate knowledge of hazards.
Mine supervision (management) with a poor understanding of
their role and responsibilities coupled with inadequate
geotechnical understanding.
A focus on mine economics and or mine production.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201912

13. The Human Factor
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14. The Human Factor
Psychological biases that distort rational decision making.
Loss aversion – The response of people to losses is stronger
than the response to corresponding gains.
- People are more sensitive to losses than
gains.
A distant problem (perceived) that requires sacrifices now to
avoid uncertain losses in the future.
Low likelihood but high consequence events.
This concept is very difficult for humans to effectively grasp.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201914

15. Bias No.1 - Loss Aversion
Mines are “noisy” environments.
Some problems are difficult, for example;
Movement of a large slope or structure.
Many times the clues are hidden, often no clearly defined
factors that give it a clear identity,
No definite time limit for when the failure will occur,
Often no single cause and
Often no single solution.
So the choice is:
“Spend $x now or risk the possibility of losing $10x at some
uncertain time in the future.”
DPI | Inaugural Mining Managers Safety Conference | 3.11.201915

16. This leads to Bias No.2 – Confirmation Bias
The tendency to either bend information or selectively choose
between facts to support existing values or prejudices or
ideas.
The construction of the best possible interpretation of the
situation.
A deliberate search (sub-conscious?) for confirming evidence.
Leads to under-exaggeration of the likelihood of events.
Particularly if large losses are associated.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201916

17. Example
Critical Examination of
Decision Making
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18. 18
Morwell
River
Diversion
2nd MRD
Northern
Batter
failure 2007
YALLOURN EASTFIELD SHOWING MAIN ITEMS
DPI | Inaugural Mining Managers Safety Conference | 3.11.2019

19. Problem Statement - Design and Setting
The 2nd MRD is a sophisticated engineering structure, with considerable
design complexity:
A highly variable, pre-existing basal topography;
Construction on top of materials with variable geotechnical
properties, fill, brown coal and soil;
Encloses some significant engineering structures; including
conveyor tunnels and diversion pipelines;
Structures were designed to deform under loading; and
Complex internal drainage and impermeable layers.
This structure carries the Morwell River and after the mine is finished
the structure will remain in perpetuity.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201919

20. Performance Status
Cracking near the embankment crest.
Cracking in the low flow channel.
Seepages on both the eastern and western sides.
A small local piping erosion.
Movement of the tunnel portal walls.
Continuing settlement.
Complex 3-D movement patterns that vary significantly along its length.
Loss of design freeboard.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201920

21. Overall Problem Statement
Mine Management has been advised there is a significant risk of failure of
the Morwell River Diversion:
“It is considered that a structure like the 2nd MRD should not
be experiencing these issues so soon after completion.”
“The concerns are not immediate stability, but performance under
critical loading events, the long term situation and the
potential for piping failure of the embankment, which is
probably the critical failure mechanism.”
If you are the Mine Management what do you do?
As the Mine Owner what would you expect Mine Management to do?
DPI | Inaugural Mining Managers Safety Conference | 3.11.201921

22. Options
1. Do nothing and ignore the warning.
2. Get another opinion.
3. Review monitoring and ground control management systems, then
bolster as assessed.
4. Provide the “warning” to the design consultants and request a
response, then do nothing.
5. Review, with design consultants, the design, design criteria and design
assumptions and cross correlate with performance factors. Then
implement remedial measures as indicated.
6. Undertake rigorous third party review in the understanding that the
major remedial works will probably be required. Include all
stakeholders, including those providing “warning”. Undertake
quantified risk studies.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201922

23. Response and Remediation Options
The option list is a continuum of responses.
Where you might progress to is influenced by a number of ‘actors’ or
possible biases in your system, including:
Degree of confidence in the design and or the designers.
Perceived ‘degree of conservatism’ of those providing the warning.
Confirmation bias regarding the post construction performance.
Technical expertise.
Experience base with these types of structures.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201923

24. Loss Aversion Bias and Confirmation Bias
Q1. What is the cost of failure of the structure?
~ $200 Million.
Q2. What is the cost of remediation?
~ $5 to 20 Million.
Q3. What is the likelihood of failure, based on the performance to date
and the complexity of the design issues?
Choice:
Which would you make:
<1 % chance of losing $200 Million?
Or
100 % chance of losing $5 to 20 Million?
DPI | Inaugural Mining Managers Safety Conference | 3.11.201924

25. Examination of the Actors and Biases
Degree of confidence in the design and or the designers?
International and National Consultants – Two companies.
But consultants have been wrong in the recent past; Northeast
Batter failure in 2007 - $240 Million loss.
Perceived ‘degree of conservatism’ of those providing the warning.
Senior people (industry leaders) with 40 years experience.
Confirmation bias regarding the post construction performance factors.
I built the structure I know it is sound.
Technical expertise of management.
Although very experienced, has only ever worked in this mine.
Not an engineer, and knows nothing about dams or river diversions.
Experience base with these types of structures.
Zero, apart from the 7 years experience with this structure.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201925

26. River Diversions
Water filled structure.
Simply open at two ends.
Like a dam.
Therefore it has all the critical design issues of a dam.
For dams there are a number of practical design considerations based
on very long world wide experience with many failures:
Never put a pipe through a dam,
The abutments and foundations are often critical, and
Most dams that fail do so on first filling.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201926

27. River Diversions - Why are they different?
Like a dam, but:
The abutments are “hidden” because the structure is
constructed on top;
First filling is rapid and associated with a peak flooding
event;
This may occur many years after the diversion has been
constructed;
May be subject to many cyclic rapid loading events over
time.
So the early time dependent performance factors are critical for
evaluating medium to long term risks.
In my experience river diversions are more demanding than a dam.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201927

28. Examination - Loss Aversion Bias
Q1. What is the cost of failure of the structure ~ $200 Million.
Q2. What is the cost of remediation - $5 to 20 Million.
Q3. What could the likelihood of failure be, if the performance to date is an
indication of real issues and the complexity of the design issues
hasn’t been fully appreciated yet?
What if the last 7 years ‘good’ performance means nothing because the
diversion hasn’t yet undergone peak loading?
Could the choice really be:
20% chance of losing $200 Million
Or
50% chance of losing $200 Million,
Versus:
100 % chance of losing $5 to 20 Million?
DPI | Inaugural Mining Managers Safety Conference | 3.11.201928

29. Options
1. Do nothing and ignore the warning.
2. Get another opinion.
3. Review monitoring and ground control management systems, then
bolster as assessed.
4. Provide the “warning” to the design consultants and request a
response, then do nothing.
5. Review, with design consultants, the design, design criteria and design
assumptions and cross correlate with performance factors. Then
implement remedial measures as indicated.
6. Undertake rigorous third party review in the understanding that the
major remedial works will probably be required. Include all
stakeholders, including those providing “warning”. Undertake
quantified risk studies.
Response was received from designers one week before failure,
advice all OK.
DPI | Inaugural Mining Managers Safety Conference | 3.11.201929

30. MORWELL RIVER
DIVERSION
The Actual Event
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31. “The peak loading event”
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32. 2.45 pm 5th June
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33. 3.11 pm 5th June
DPI | Inaugural Mining Managers Safety Conference | 3.11.2019

34. 10.29 am 6th June
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35. 11.08 am 6th June
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36. Post Collapse
Profile
DPI | Inaugural Mining Managers Safety Conference | 3.11.2019

37. 8th June
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38. The Scale of Hazards
and
Risks
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39. Stability Problems at all Scales:
• Very Large Post Failure Deformations
• Large Blocky Failures And Collapses
• Bench Failure
• Rockfall
• Small Individual Blocks
DPI | Inaugural Mining Managers Safety Conference | 3.11.201939
MINE FAILURES

40. Very Large Post
Failure Travel
DPI | Inaugural Mining Managers Safety Conference | 3.11.201940

41. DPI | Inaugural Mining Managers Safety Conference | 3.11.201941
OVERALL
VIEW
Grasberg

42. DPI | Inaugural Mining Managers Safety Conference | 3.11.201942
THE FLOW PATH
POST FAILURE

43. DPI | Inaugural Mining Managers Safety Conference | 3.11.201943
FLOW PATH
MID SLOPE

44. FLOW PATH
LOWER SLOPE
MID HEIGHT
BENCH 80m WIDE
DEATHS
OCCURRED HERE
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45. DPI | Inaugural Mining Managers Safety Conference | 3.11.201945
DRILL,
SHOVEL AND
TRUCKS

46. DPI | Inaugural Mining Managers Safety Conference | 3.11.201946
TRUCK

47. DPI | Inaugural Mining Managers Safety Conference | 3.11.201947
MONITORING

48. QUALITATIVE PROBABILITY EXPRESSIONS AND QUANTITATIVE
PROBABILITY EQUIVALENTS
Reagan, R.T., Mosteller, F., and Youtz, C. 1989. Quantitative meanings of verbal probability expressions. The Journal of Applied
Phychology, 74: 433-442. doi:10.1037/0021-9010.74.3.433. PMID:2737992.
48

49. Blocky Rock Failure
DPI | Inaugural Mining Managers Safety Conference | 3.11.201949

50. Mt. KEITH OVERALL SETTING - CUTBACK
HAUL ROAD
ON OUTSIDE
OF CUTBACK
DPI | Inaugural Mining Managers Safety Conference | 3.11.201950

51. TRUCK IN
WATER
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52. ROCK
MASS
FABRIC IN
CUTBACK
DAYLIGHTING
PLANES
SLOPE AT THE LIMIT WITH STRUCTURE PARALLEL OR DAYLIGHTING
CONTINUOUS
ROCK
STRUCTURE
FABRIC
DPI | Inaugural Mining Managers Safety Conference | 3.11.201952

53. PREVIOUS FAILURE OF SAME TYPE ON THE SAME SLOPE AT
HIGHER ELEVATION - ALSO AFFECTING HAUL ROAD
HAUL ROAD RE-ROUTED
DPI | Inaugural Mining Managers Safety Conference | 3.11.201953

54. Bench Failure
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55. LAWLERS GOLD
MINE
JANUARY 2003
DPI | Inaugural Mining Managers Safety Conference | 3.11.201955
Earlier inspection of
the wall shortly
before the event by a
geotechnical
consultant and other
staff gave no
indication that failure
was imminent.
Death of an Ore Spotter
While standing on
bench

56. Prior to
Failure
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57. Small Block
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58. Mantos
Diagrama de sucesos
Accidente Fatal
29 de octubre de 2003
Operaciones Mina Rajo Abierto
División Mantos Blancos
DPI | Inaugural Mining Managers Safety Conference | 3.11.201958

59. Zona de probable
desprendimiento de la
roca.
Berma que delimita distancia
para interactuar con el
talud del sector.
Talud 37° de pendiente.
Cargador Frontal 8703,
operado por Jorge Campos,
a quien se le iba a entregar
el material de limpieza.
Imagen frontal del sector del
suceso.
Posición final de
Camioneta siniestrada

60. Imagen tomada desde el banco
780 hacia el banco 756.
Barra de perforación,
con 6 metros de avance
aproximadamente.

61. Path of rock

62. Berma que delimita el
acecamiento a la zona
de riesgo identificado.
Imagen tomada desde el banco
756.

63. 45 mt.
25 mt.
Distancias de la camioneta hasta
el talud y berma delimitadora de
distancia.

64. Imagen tomada en el banco 684,
sector del incidente.
Fragmentos de la roca.

65. Fragmentos de la roca.
Imagen tomada en el banco 684,
sector del incidente.

66. Zona del impacto directo
de la roca en la
camioneta.
Imagen tomada en el banco 684,
sector del incidente.

67. Lessons
Role of history in stability.
Experience with moving slopes.
Understanding post failure travel potential.
Experience base used to predict future performance, is it adequate or appropriate?
Monitoring must be right.
If the environment is different will the performance be the same.
Potential risks at all scales.
Not feasible to completely remove the risk.
In mining we are always balancing safety and economics.
Fundamental importance of understanding the potential for biases affecting our
thinking.
The importance of critically examining estimates of likelihood or probability.
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68. DPI | Inaugural Mining Managers Safety Conference | 3.11.201968

69. THANK YOU
QUESTIONS
DPI | Inaugural Mining Managers Safety Conference | 3.11.201969