Cleaning Near Moving Conveyors
Presenter: Jeroen Maaren
COALTECH RESEARCH ASSOCIATION
ANNUAL COLLOQUIUM
22 July 2011
Problem Statement
•
Current conveyor regulations promulgated 2008
− Prohibits cleaning any conveyor belt installation as
long as any of its parts are in motion
•
Only three changes are sought
− Distinction between high risk and other areas
•
•
•
Drives, take-ups, snub & tail pulleys and transfer points
No change – other than concession – use HP water jet
What about mechanised cleaning
g systems?
y
− Other areas routinely cleaned while running
•
•
Appropriate procedures in place
M
Manual
l labour?
l b
?
− Tracking & alignment set while belt’s in motion
•
Appropriate
pp p
procedures
p
in place
p
Problem Statement
•
Many mines battling sever production pressure
− To meet targets – have to keep running
− Comply
p y with regulations
g
by
y cutting
g back on shutdowns
•
•
Reduced cleaning and maintenance
Resulting snow-ball effect
− Urgent intervention needed to prevent meltdown
•
Coaltech devised this research p
project
j
to define
this very problem and seek solutions
Introduction
•
Project purpose
− Define the moving conveyor cleaning problem
− Identify
yp
practical & safe means to clean all areas of
moving conveyor systems
•
•
Especially including high risk areas
Found that industry facing a big problem…
Research Methodology
•
Data sources
−
−
−
−
•
Internet based background literature study
Legislative
g
appraisal
pp
Industry wide consultation interviews
Review of typical operating conditions
Solution categories
− Existing cleaning options
− Options
O ti
to
t reduce
d
cleaning
l
i load
l d
− Options to reduce spillage
Learning
•
Two mines report ‘no’
no conveyor problems
− What are they doing that works?
− At first – No discernable difference
•
•
All seemed to have the same sort of policies and
procedures in place, doing much the same thing
Then became clear
− Difference seemed to come down to ATTITUDE…
•
•
•
•
•
Using
g available passive
p
belt cleaning
g devices
Keeping passive devices in pristine working order
Apply strict cleaning and maintenance schedules
Seeing con
conveyors
e ors eq
equally
all important to prod
production
ction
Appointing employees with a passion for belting
Learning – What
What’s
s going wrong?
•
Definitions
− Fundamental aspect
•
•
Large array of passive belt cleaning devices available to
industry
Even if all implemented right
−
−
WILL still have Carry-back
y
past passive
p
p
belt cleaning
g
devices
WILL have fallout along length of conveyor return
− First rule: Proper design
− First hurdle: Installing and maintaining min. set of
recommended passive belt cleaning systems
− Second hurdle: Implementing effective cleaning
processes
Learning – Fundamentals
•
What’s
What
s happening
happening…
− All mines design conveyor systems to accepted std
•
But few expand design criteria to specifically address
and assist cleaning – breaking the first rule
− All mines have passive cleaning devices in place
•
•
Most mines visited moderately to poorly maintained
Falling over first hurdle
− All mines have cleaning processes in place
•
•
Most mines visited showed clear signs of accumulated
waste under and around conveyors
Falling
g over second hurdle
− Are the fundamentals in place?
Results – Data base
•
Available Cleaning technologies
−
−
−
−
Passive belt cleaning systems and devices
Manual labour aids/utensils
Machinery suitable for immediate niche application
Promising base cleaning machinery platform
•
Requiring further development
Results – Data base
•
Heard of a book called ‘Foundations
Foundations 4
4’?
?
− 500+ pages on one topic only
•
•
Cleaning conveyor belts!
Only 1 of 22 conveyor experts interviewed
− FREE PDF download
Data Base – Passive belt cleaning
devices
•
Passive belt cleaning systems/devices
− Contains everything important related to passive belt
cleaning devices and systems
•
Defining belt cleaning load and efficacy
− Carry-back
•
•
•
Stuff clinging to belt after passing tipping point
Quantified – g/m2
Exact value vary
yp
per installation
−
•
Belt material/coal properties, age, moisture content, etc
Foundations 4, p231-232: R. Todd Swinderman’s
performance based scale referenced
−
Defines 3 levels of cleanliness
Data Base – Passive belt cleaning
devices
•
Cleaning efficacy
− Level 1
•
•
•
•
Least effective cleaning level
Hardly any passive belt cleaning devices properly
maintained ALL the time
250+ g/m2 Carry
250
Carry-back,
back, 75 % fallout
1.2 m belt, 83 % loaded (1 m), moving 3.5 m/s
−
•
Fallout accumulation: 2.4 ton/hr or 14.4 ton/6hr shift
6 of 8 mines visited seemed to clean at this level
Data Base – Passive belt cleaning
devices
•
Cleaning efficacy
− Level 2
•
•
•
•
Cleaning much better – have minimum recommended
passive belt cleaning devices in place
ALL passive belt cleaning devices properly maintained,
ALL the time
100 g/m2 Carry-back, 50 % fallout
1.2 m belt, 83 % loaded (1 m), moving 3.5 m/s
−
•
Fallout accumulation: 0.6
0 6 ton/hr or 3.6
3 6 ton/6hr shift
2 of 8 mines visited seemed to clean at this level
Data Base – Passive belt cleaning
devices
•
Cleaning efficacy
− Level 3
•
•
•
•
Level 2 devices, PLUS wash bays in place (single & multistage wash areas)
Cleanliness systems become exponentially expensive
with increased level of cleaning
10 g/m2 Carry-back, 25 % fallout
No mines cleaning to this level
Data Base – Passive belt cleaning
devices
•
Special mention
− Designated loading zones
•
•
•
Ostensibly at any point where belt direction suddenly
changes, increased roller pressure causes highly
accelerated carry-back fallout
Observation shared and discussed during mine visits
If done deliberately, designated loading zones result
−
−
•
Location chosen – Can then be managed
Could reduce fallout elsewhere
Requires further scientific quantification
− Belt turnovers
•
•
Costly, bulky, etc. – out of favour
Areas where one cannot clean daily/weekly
−
Level 3 cleaning needed – comparable efficacy to
wash boxes, without adding water treatment
problems
Data Base – Manual labour
•
Utensils – shovels and scrapers
− Developed for cleaning near moving conveyors
•
•
Improved safety – difficult to grasp firmly
Inefficient – now the industry standard
− Manual labour – industry accepted norm
•
•
•
•
Simple, flexible,
Simple
flexible adaptable
Considered inexpensive
Laborious, thankless and repetitive task
Cost effective?
−
−
Hidden costs?
Unproductive,
p
risk prone,
p
tiring
g
− Need mechanised alternative to clean areas
•
Practically NO ONE seems to be conducting
serious R&D into mechanised cleaning!
Data Base – Suitable Machinery
•
Miniaturised machinery
− Found four remote control machines
•
•
Brokk
Two demolition robots operating off electrical
tethers
•
Husqvarna
… found many more!
Data Base – Suitable Machinery
•
Miniaturised machinery
− Found four remote control machines
•
Other two diesel powered
•
Kanga
Data Base – Suitable Machinery
•
Miniaturised machinery
− Found four remote control machines
•
Other two diesel powered
•
Dugless
Data Base – Suitable Machinery
•
To be miniaturised!
− Truck and trailer mounted vacuum systems
Data Base – Possible cleaning
platforms
•
Base platform machinery holding promise
− Array of miniaturised earth moving machinery
− Over 200 manufacturers worldwide
− Mini defined as machinery weighing 0.7 to 7.5 tons
•
•
Tracked or trackless
Skid steered
t
d or centre
t articulated
ti l t d
− Four categories
•
•
•
•
Mini Excavators
Mini Loaders
Mini Dumpers
Mini Backhoes
Data Base – Possible cleaning
platforms
•
Mini Excavators
Data Base – Possible cleaning
platforms
•
Mini Loaders
Data Base – Possible cleaning
platforms
•
Mini Dumpers
Data Base – Possible cleaning
platforms
•
Mini Backhoes
Operational Considerations
•
Three types of conveyor systems considered
− Underground, overland and plant
•
Overshadowing factors
− Underground: Confinement, isolation and undulation
(floor & wall)
− Overland: Occasional spillage, relative ease of access
− Plant: Working at heights, confinement and narrow
walkways
•
Focus
Foc
s on underground
ndergro nd conveyors
con e ors (in all its
facets)
− We all know what these areas look like…
Summary Conclusions
•
Only viable means to clean majority of conveyor
systems is manual labour
− Mechanised support – in niche applications only
•
Some mines coping well under current
regulations
− But not all mine able to duplicate this feat
•
•
Hardly anyone conducting serious R&D into
mechanised cleaning to replace manual labour
Only technical developments taken place in
passive belt cleaning systems
− Fundamental
F d
t l limitation
li it ti – always
l
have
h
Carry-back
C
b k
− ALWAYS need to clean along conveyor length
Summary Conclusions
•
Most mines only cleaning belts to Level 1
− Best managing Level 2 – Still significant fallout
•
Seeking changes to legislation to allow manual
labour cleaning while belt is moving
− Fails to redress the need to find viable alternative to
manual cleaning
•
Currently – No viable mechanised cleaning
systems
− Four remote controlled mini-machines found
− None flameproof and generally applicable
− Local skid-steer machines flame proofed – perform
supportive roll to augment manual cleaning
Summary Conclusions
•
Potential base technologies found
− Truck and trailer mounted vacuum systems
− Over 200 mini earth moving
g machinery
y manufacturers
•
Structured approach that works…
−
−
−
−
1: Upgrade passive system to best affordable
2: Maintain passive systems in pristine condition
3: Make cleaning as important as production
4 E
4:
Establish
t bli h strict
t i t regular
l cleaning
l
i
& maintenance
i t
schedules
− 5: Establish/Invest in mechanised cleaning
g R&D
− Note: No mention of regulation changes…
Recommendations
•
•
Ensure fundamentals in place
Conduct R&D into mechanised cleaning
− Augment, but later replace, manual cleaning
•
Starting point concept – a combination of…
− a horizontally
y mounted excavator arm
− mated to mini cyclone filtration and vacuum systems
− mounted on various miniaturised machinery support
vehicles
hi l (breakout,
(b
k t cleaning,
l
i
collection,
ll ti
dumping)
d
i )
− operating remotely/autonomously
− ... should yield promise
•
Lot of potential to conduct mechanised cleaning
R&D
Thank you!