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Your Organisation
• What triggers your organisation to perform an RCA?
• Easy… These typically cause significant production losses
• Shutdown Extensions
• Explosions or other event that may cause injury
• What triggers your organisation to perform an RCM study?
• Typically smaller losses that add up or Reliability issues on
bottleneck assets
• Poor Maintenance Strategy
• Poor Spares Management and/or Resource Levelling
• How often does your organisation review its’ maintenance
strategies?
• Answers I’ve heard in the past…
• Never
• Every 24 months
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Why Use Process Reliability
• The Weibull process reliability techniques help define a
strategic course of action for making improvements.
• The look down technique provides opportunities for
developing a strategy to solve problems.
• The method tells the nature of
problems and quantifying the
losses.
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Analysing a PR Chart
The reliability of the process is defined at
the point where the trend line, in the
upper reaches of the production, began
their losses at a cusp.
A portion of the losses appear as cutbacks.
Another portion of the losses appear as
very severe problems characterized by a
zone labeled crash and burn---both zones
are associated with reliability problems.
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Nameplate Values
• NAMEPLATE Eta
– The maximum plant capacity under assumed ideal operating and control conditions. This
value can be however obtained by taking an average of the best 15 production results.
• NAMEPLATE Beta
– Manually set to 75 (or other pre-determined value). Beta of 100 is seen to be “world class”
production, achieving highly consistent results.
– Improvement in Nameplate Values will occur as the consistency of throughput is increased
as a result of focussing on both Production and Reliability losses
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Production Values
• PRODUCTION Eta
– Production Line tonnes are based on the Weibull analysis performed using the daily production data,
returning a value where the production data line (best of fit) intersects with the Eta estimator (63.2% of
production results are below)
• PRODUCTION Beta
– The Characteristic Shape, or slope of the Weibull Distribution.
In Process analysis, this represents the consistency in the plant’s outputs. The lower the number, the
lower the consistency or increase in variability within the process.
– Production Losses are typically related to;
• Utilisation
• Efficiency
• Process variability
• Equipment Operating Characteristics
• Systemic issues
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Reliability Losses
• Total Reliability & Loss
– Reliability point is where there is a cusp in the production points plotted on the Weibull chart. This
represents the point where production becomes inconsistent or unreliable. The loss value is the
difference between demonstrated capacity and are the points at which the production values lie to
the left of that capacity line
– The cusp for the point of reliability represents probability the capacity (tonnes) is likely to be
achieved or greater.
– i.e at this point a 90.34% probability of achieving 382.3 tonnes or greater
– Losses here equate to “Given” tonnes lost per day through reliability plant issues
such as breakdowns
– Reliability losses should be targeted with a formailised RCA Defect Elimination Process with
defined trigger points to reduce variability in plant throughput. This will result in higher eta and
beta Production values which represents increased throughput consistency
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12 Month Analysis Profile
Profile
Production
Losses
Reliability
Losses 1
Dec 11 Jan 12 Feb Mar Apr May Jun Jul Aug Sep
Month
0
25
50
75
100
125
150
175
200
225
LostCapacitytonnes
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How To Improve?
• What is the issue?
• Reliability or Process?
• How to deal with those issues?
• Do those issues change over time?
• How to quantify improvements?
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Using a Reliability Block Diagram (RBD)
to Help Make Decisions
• An RBD is a logic diagram that describes a system behaviour
and easily allows different scenarios to be analysed.
1.1
Prim ary Crushing
System
(97.45)%
1.2
40,000tonneLive
Coars eOrePile
System
(95.46)%
1.3
Sec ondary
Crus herFeed
Conveyor
621-CVR-0-02
M TTF=100.6
M TTR=0.92
100%
1.4
Sec ondary
Crus hingSystem
(99.71)%
1.5
Coars eScreen
FeedConveyor
622-CRV-0-03
M TTF=144.2
M TTR=1.65
100%
1.7
HRGRFeed
Conveyor
623-CVR-0-04
M TTF=173.5
M TTR=1.15
100%
1.8
HPGRSy stem
(87.63)%
1.2.1
Coars eOrePile
TTE=96
TFL=12
100%
1.11
FineSc reening
andBallMill
System 1
(24.48)%
1.12
FineSc reening
andBallMill
System 2
(24.45)%
1.13
FineSc reening
andBallMill
System 3
(24.52)%
1.14
FineSc reening
andBallMill
System 4
(24.44)%
1.26
Coars eScreen
Feeder
623-FDV-1-01
M TTF=64.8
M TTR=0.45
35%
1.27
Coars eScreen
623-SCR-1-01
35%
1.28
Coars eScreen
Feeder
623-FDV-2-01
M TTF=64.8
M TTR=0.45
35%
1.29
Coars eScreen
623-SCR-2-01
35%
1.30
Coars eScreen
Feeder
623-FDV-3-01
M TTF=64.8
M TTR=0.45
35%
1.31
Coars eScreen
623-SCR-3-01
35%
1.32
Coars eScreen
Feeder
623-FDV-4-01
M TTF=64.8
M TTR=0.45
35%
1.33
Coars eScreen
623-SCR-4-01
35%
1.34
12WShutdown
TTF=1000000
M TTR=0
100%
1.35
1YRShutdown
TTF=1000000
M TTR=0
100%
1.36
6WShutdown
TTF=1000000
M TTR=0
100%
Copy Of1.8.17
FineOreBin
625-BIN
TTE=2.27
TFL=1.19
100%
Example of a crushing circuit
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Is there something in that system we can
target?
• Lets take a look at the problem system in detail
Example of the Secondary Crushing System
BN-003
Secondary Screen
Feed Bin 1
FE-002
Secondary Screen
Belt Feeder 1
BN-004
Secondary Screen
Feed Bin 2
FE-003
Secondary Screen
Belt Feeder 2
SC-002
Secondary Screen
1
SC-003
Secondary Screen
2
CV-003
Conveyor CV03
BN-006
Secondary
Crusher Feed Bin
1
BN-007
Secondary
Crusher Feed Bin
2
FE-005
Secondary
Crusher Feeder 1
FE-006
Secondary
Crusher Feeder 2
CV-004
Conveyor CV04
CR-002
Secondary
Crusher 1
CR-003
Secondary
Crusher 2
PP-004
Dust Scrubber
Slurry Pump
PP-010
Sump Pump
PP-011
Sump Pump
DC-003
Secondary
Screening Dust
Scrubber
AU10-PPP-CRU-BLDNG-BD002
BUILDING,
SECONDARY
SCREENING
AU10-PPP-CRU-BLDNG-BD003
BUILDING,
SECONDARY
CRUSHING
F-004.1
No Capacity
Consequence
Sub-system F-004
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What to do in the Problem System to
Improve Production?
In this example CV04 and CV03 have the biggest impact on production.
0 200 400 600 800 1000 1200 1400 1600 1800
Conveyor CV04
Conveyor CV03
Secondary Crusher 1
Secondary Crusher 2
Secondary Screening Dust Scrubber
Secondary Crusher Feeder 1
Secondary Crusher Feeder 2
Contribution to Capacity Loss (Thousand $)
Component
Contribution to Capacity Loss over 10 YRS
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Implementing The Strategy
• Reliability Block Diagrams (RBD)
– Utilise an Availability Simulation to predict production
increases with different scenarios.
How does a redundancy
scenario change production?
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Implementing Your Strategy
• Reliability Block Diagrams (RBD)
– Utilise an Availability Simulation to predict production
increases with different scenarios.
What predicted impact will a
RCM have on our production?
MTTF goes from 8760
to 4860 through RCM
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Conclusions
• Step One
– Identify room for improvement
• Step Two
– Identify the best improvement that can be made.
• Step Three
– Quantify the cost benefit in the options available for
improvement through statistical methods.
• Step Four
– Analyse the data to see what impact decisions have on the
business.