conveyor operations · conveyor guarding is the most critical aspect of conveyor safety. conveyors...
TRANSCRIPT
“Safety Starts With Me”
Conveyor Operations
“Safety Starts With Me”
This presentation covers the conduct of conveyor
operations in the coal and metalliferous mining
industries. It includes: planning and preparing for
conveyor operations, operating conveyors and
carrying out operator maintenance.
This unit applies to the movement of material via a
conveyor system in the extractive process and is
appropriate for those working in operational roles
and worksites within: coal mining and metalliferous
mining.
Overview
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Conveyors are the most common method of
transporting material from one location to another
because they are often the most cost effective and
practical. They are adaptable to conditions,
locations and type of material to be transported.
Conveyors come in many types; some are used to
transport luggage, people and wet or dry material.
Conveyors in a processing environment must not be
used for transporting people. Serious injury or death
could result.
Introduction
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Conveyor Safety
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Whilst belt conveyors are an efficient method of transporting ore, if safe operating and maintenance practices are not followed, conveyors
have the potential to be one of the most dangerous pieces of equipment in a mining operation.
The Mines Safety & Inspection Regulations require that conveyors MUST be fitted with appropriate safety guards and other safety
equipment and procedures/instructions that provide for the protection of personnel working around them. Conveyor safety requirements
can include but are not limited to:
• Guarding to prevent access to moving parts / nip points
• Conveyor stop/lanyard rope switches
• Emergency Stop buttons
• Restricted access areas
• Properly maintained access ways
• Safe Procedures/Instructions for working on or around conveyors
Conveyor Safety
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Conveyors are a major hazard in the workplace. Always take extreme care when
working around conveyors.
Even when guarding is securely in place, some conveyors will have exposed
moving parts. Avoid getting any part of your body, loose clothing or anything you
are holding too close to moving machinery.
As well as moving parts, conveyor systems will often produce hazardous levels of
dust and noise. Appropriate controls, including personal protective equipment,
must be used before working in these hazardous areas.
Some of this work may include work at heights or in confined spaces. Ensure that
all safety procedures are followed and the appropriate permits issued prior to the
commencement of work.
Conveyor Safety
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Please obey the following rules for working around conveyors:
STOP the conveyor if life or equipment is in danger
NEVER step on or ride on conveyor belts
NEVER attempt to remove material from moving conveyors
NEVER take short cuts under or over moving conveyors, or a conveyor that has not been isolated, locked and tagged by an
Isolation Officer and yourself.
NEVER put anything past the pull wire….ANYTHING!
NEVER adjust a roller when a conveyor belt is in operation
NEVER work on a stopped conveyor without following the correct isolation and tagging procedure
NEVER remove guards without following the correct isolation and tagging procedure
NEVER operate a conveyor when the guards are removed or missing
NEVER wear loose clothing when working or walking around moving conveyor belts
NEVER shut down a conveyor if there is smouldering product underneath
NEVER shut down a conveyor if a roller is red hot
Conveyor Safety
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Operator’s Responsibilities
The primary responsibilities of the process operator are to ensure that safety; throughput, production and quality standards are
maintained. The operator must have a good understanding of the function and operation of the conveying systems within their
area. This includes:
• What each type of conveyor does
• What each conveyor’s carrying capacity is
• The importance of each conveyor in relation to the area’s processes
Procedures for Working with Conveyors
• Each plant area has safe work procedures or instructions for working around conveyors. They are to ensure your safety
while performing the task and MUST be complied with.
• As with all tasks, regardless of whether or not there is a procedure or work instruction, you must perform a pre-task hazard
analysis. If you are unsure about the safety of a particular task, contact your supervisor.
Conveyor Safety
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It is BCS policy, as well as a Mines Safety & Inspection Act & Regulation requirement that where there is a risk of exposure to
the hazards of moving equipment/machinery, all safety guards must be in place prior to the operation of any equipment.
Conveyor guarding is the most critical aspect of conveyor safety. Conveyors are in continual motion and have many moving
parts/nip points. A nip point is where the moving belt is in contact with a revolving support roller or pulley (see below). Anything
that gets caught between the belt and the roller willed be ‘nipped’ and get pulled in.
Guarding
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Guards are in place to eliminate
potentially life-threatening situations
by preventing contact with moving
equipment.
A typical conveyor guard set up is
shown right.
Guarding
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Access walkways are designed to provide safe passage
around conveyors. Because of their close proximity to
conveyors, all access ways must, as far as is practicable,
be kept free of trip hazards. Trip hazards may include
hoses, ore spillage, equipment and tools.
Where it is possible to get access to a conveyor, there
must be a readily available emergency stop. This will be
a lanyard rope switch along the full length of the
accessible section of the conveyor.
The rope switch is a plastic coated wire cable connected
to a switch box. Pulling the rope switch will crash stop
the conveyor.
Conveyor Stop/Lanyard Rope Switch
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The switch box initiates the conveyor crash stop. To reset the conveyor for operation, the activated switch box must be
located and reset. Prior to any reset, the cause of the conveyor stoppage must be identified and addressed.
Switch Box
Pull Wire Switch Boxes
Rope switches are emergency stopping devices only. They are not to be used as conveyor isolating devices.
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Emergency Stop Buttons
Emergency Stop buttons for conveyors are part of a conveyor’s Local Stop/Start station and are usually located adjacent to the
conveyor drive. They can also be located at strategic locations along a conveyor. Pushing in the stop button on the local Stop/Start
station will also crash stop conveyors. To reset, simply pull the stop button out.
WARNING: Emergency stop buttons are NOT conveyor isolators.
Note: The Start button will only work when Local is selected on Scada mimic. The selector switch MUST NOT be operated unless the
conveyor has stopped.
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Restricted Access
On some conveyors there are areas where there is restricted access. Generally, these areas have moving conveyor belts or
associated equipment, e.g. take up weight areas, or a conveyor tail areas (below).
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Audible and Visible Start up Alarms
All conveyors have pre-start sirens and amber flashing warning light. The siren will sound and the light will start flashing
approximately ten seconds before the conveyor is about to start.
Note: They are a warning device only and offer no protection.
If a conveyor starts up without the siren sounding or the light flashing, you must report it to your team leader.
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Conveyor Description
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Belt Conveyors
Belt conveyors are one of the most important components of mineral processing. They are a material handling system that
provides the means of transporting dry or semi dry ore through the various stages of processing.
Conveyors are generally trouble free, running continuously for long periods without breaking down. The simple design of an
endless belt supported by rollers and drive motors ensures a reliable method for transporting materials.
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Conveyor Applications
Conveyors are designed for a specific purpose, however most
have the same basic components; a head pulley, a tail pulley,
drive system, a belt, rollers, support framework and safety
devices.
Feed systems for conveyors are designed to deliver material to
the moving conveyor without spillage or damage to the
conveyor.
The conveyor carries the material at the end of one process
and discharges at the beginning of the next process. The
beginning of the next process can be a stockpile, a bin, a
transfer chute or actual loading of ships, trains and trucks.
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Work Requirements
All operational and maintenance work on and associated with conveyors must be performed in accordance and compliance
with:
• BCS and Client requirements; this includes but is not limited to Standards, Procedures and Work Instructions
• Occupational Health and Safety Acts and Regulations, and licensing requirements for operation of specific equipment.
• Other relevant legislation; including the Mines Safety & Inspection Act and Regulations.
• Manufacturers guidelines and specifications
• Australian Standards where applicable
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Speed Sensing
Conveyor speed sensing is done with proximity switches at the conveyor non-drive end pulley. The switches detect flags
rotating on the pulley. There are two proximity switches and each of the switches detects each of the pulley flags separately.
The high speed counter has a separate counter for each of the switches.
Each of the counters generates a count rate value and the two are compared to determine the correct operation of the
proximity switches. The VSD speed signal is also used in the speed comparison in order to detect a conveyor under speed
condition that will trip the conveyor.
Proximity Switch
Target Ring Flags
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Conveyor Components
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Conveyor Components
A belt conveyor is an endless looped belt that transports material from a source (feed point) to a destination (discharge point);
it is usually driven by an electric motor connected to a reduction gearbox through a coupling.
The top side of the belt is supported every metre by a set of trough idlers and every seventy-three metres guided by a set of
tracking idlers. At the feed point, impact idlers are positioned to absorb the impact of ore falling onto the belt. The return side
of the belt is supported by return idlers and guided by return tracking idlers.
The major components of a belt conveyor are:
• Belt
• Framework/Walkway
• Head Pulley
• Drive System
• Gravity/Counterweight and Pulley
• Bend Pulleys
• Tail Pulley Hold back brake
• Belt cleaning devices (primary scraper)
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Belt
The belt consists of one or more layers of material. They can
be made out of rubber. Many belts in general material handling
have two layers. An under layer of material to provide linear
strength and shape called a carcass and an over layer called
the cover.
The carcass is often a cotton or plastic web or mesh.
The cover is often various rubber or plastic compounds
specified by use of the belt. Covers can be made from more
exotic materials for unusual applications such as silicone for
heat or gum rubber when traction is essential.
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Drive System
The drive system is the point of contact between a power
transmission belt and its pulley. A conveyor belt uses a wide belt
and pulleys and is supported by rollers or a flat pan along its path.
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Conveyor Head
The head/discharge end of the conveyor is often
the drive pulley and it is where the belt begins its
return journey to the tail end.
Immediately behind the head/drive pulley is a snub
pulley which increases the “wrap” of the belt
around the drive pulley. If the drive pulley is
located elsewhere, the drive/snub pulley
arrangement still applies. There is no snub pulley at
the tail end. The tail end of the conveyor is usually
just before the feed point; the tail pulley is where
the belt begins its return journey to the head end.
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Belt Feeders and Apron Feeders
A Belt or Apron feeder generally has a much slower belt speed than a conveyor, but transports heavier/larger
loads over a shorter distance (below). Depending on the feeder, belt tension and tracking are adjusted either by
screws or hydraulic rams attached to the tail pulley.
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Pulleys
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Pulleys
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Tail Pulley
The Tail Pulley at the rear of the conveyor turns the belt towards the discharge end of the conveyor. It may be a
drive pulley or an idler pulley.
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Head Pulley
The Head Pulley, at the discharge end of the conveyor, turns the belt towards the tail of the conveyor.
It may be a drive pulley or an idler pulley.
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Snub Pulley
A Snub Pulley is an idler pulley, positioned to increase the contact arc or “wrap” between a belt and a
drive pulley and reduce belt slippage.
When used in a wrap drive, it has the added function of changing the direction of the return belt travel.
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Drive Pulley
The Drive Pulley is coupled to the conveyor drive gearbox and transmits energy from the drive unit to the belt. It may
act as the Head or Tail Pulley or be located anywhere else within the conveyor system. Fluid coupling is only applicable
to direct drives and are not used on conveyors with Variable Speed Drives (VSD).
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Bend Pulley
The Bend pulley is an idler pulley used to change the direction of travel of the belt other than at the ends of the
conveyor.
Normally found as part of the “Take Up” section of the conveyor system
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Tension or Take-Up Pulley
To prevent belt slippage and tracking problems, the conveyor belt must have tension applied to it. Tension is applied to
the conveyor belt by a gravity weight, suspended from a counterweight pulley, or by a winch tension system. Because
the counterweight pulley can move without warning it is housed and guarded inside a take up tower.
Above the counterweight pulley are bend pulleys which support the counterweight and change the direction of the belt.
For feeder and stacker belts, tension is applied by forward or backward adjustment of the tail or head pulley.
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Conveyor Rollers or Idlers
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Conveyor Rollers or Idlers
Throughout the length of each convey or feeder the rubber belt is supported, shaped and guided by rollers or idlers of
different types (below). Each type of idler serves a specific purpose. Some of these types are shown on the following
pages. Certain idlers/rollers are suspended from the framework instead of being mounted in frames.
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Transition Rollers (Idlers)
As the conveyor belt leaves the tail pulley, the belt profile is flat, but has to change to a trough shape before the loading
point to reduce spillage. This change in profile is carried out by sets of transition rollers. The transition rollers are
usually in sets of two but can be one set & are also used at the head end to aid in the transition to a flat profile again.
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Trough Rollers (Idlers)
As the name suggests, these rollers sit in a frame that forms the shape of a trough (below). The shape allows the belt
to carry ore without spillage. They are constructed from light steel, and spaced approximately one metre apart. They
also give the belt rigidity and help control direction.
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Impact Rollers (Idlers)
Impact rollers are located and spaced at 25cm centres under the belt at each loading point. They have a ribbed rubber
outer to absorb the impact of falling ore. Because of their rubber construction they are also fitted under magnets and
metal detectors.
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Tracking Frames and Servo Rollers
Every 73 metres of a conveyor belt, tracking frames, are installed on the topside (trough shape), and on the return side
(flat shape). These frames are pivoted in the middle and are fitted with servo rollers for tracking purposes.
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Return Rollers
The return rollers are fitted at 3 metre centres underneath the full length of the return strand of the belt. They are
usually a single roller the full width of the belt (below).
On very wide conveyors they may be made up of two shorter rollers with a slight trough profile. This type is
occasionally found above the return strand, just before a bend pulley, to aid in tracking
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Each conveyor feed chute is constructed to fit centrally over the conveyor belt to assist tracking. Most chutes are lined with
replaceable molybdenum wear plates and have built in rock ledges to reduce the impact of falling ore onto the belt.
Feed chutes are fitted with skirts to prevent ore spillage and to contain the dust, which in some cases is drawn out by a
dust extraction system. The skirting is either rubber or linatex.
The skirts are fitted to just contact the belt and can be adjusted to compensate for wear. Adjusting of wedge and spring
clamped skirting is achieved by loosening the clips (remove wedge/release spring) and moving the skirt down to contact the
belt and re-tighten clips. The strip washer direct bolted skirting is replaced whenever it is worn to a point where it no longer
prevents spillage and dust containment.
Feed Chute
Skirting Arrangement
As with any conveyor maintenance or adjustments,
the conveyor MUST be isolated, locked and tagged
out.
N.B. Worn skirting needs to be replaced ASAP to
prevent spillage and to help with dust extraction and
must be disposed of into the appropriate ‘rubber’
skips
Chutes and Skirts
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Primary Scraper
The primary scraper unit is installed at the head pulley and the
blades are adjusted to fit hard up against the belt just below the
stream of discharging ore (right). It removes the majority of
material stuck to the belt after ore discharge.
Secondary Scraper
The secondary scraper removes any residual material the primary
scrapers have not removed. They are normally positioned behind the
head or snub pulley.
Belt Cleaning Devices
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Vee or Plough Scrapers are usually located before bend or tail pulleys. As the name suggests the Vee Scraper is shaped like a
V and sits across the belt (right).
The plough Scraper is angled across the belt. They are deflectors that prevent rock from passing between the pulley and the
belt.
Belt Scrapers are safety devices for conveyors. They are designed to minimise the build-up of material around pulleys and
rollers and prevent damage to the belt caused by the material or ‘drifting’.
Regular visual inspections of all belt scrapers in your area must be a part of your daily checks.
Vee/Plough Scrapers
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Each conveyor motor has an electrically operated, hydraulically driven,
thruster brake on the coupling, between the motor and the gearbox. Each
of the motor's thruster brakes is driven by a DOL motor and brake
solenoid. A pressure transmitter in the hydraulic system is used to detect
the brake lifted condition and to cycle the motor at a slightly greater
pressure to keep the brake lifted:
• Pressure alarm low- low (PALL) - brake lifted condition
• Pressure alarm low (PAL) - brake motor ON pressure control point
• Pressure alarm high (PAH) - brake motor OFF pressure control point
The brakes are lifted before the conveyor main drive is started. The brake
lifted signal must be received by the PLC before the conveyor drive
accelerates from zero speed. The brakes are applied at the same time
the conveyor stop signal is activated. When the brake is applied the brake
motor and brake solenoid are de- energised
Conveyor Brakes
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Each motor brake has a local BRAKE TEST pushbutton station that
enables the brake to be energised locally. The test function will only
operate with the brake motor in JOG mode.
Note: When the brake motor is in JOG mode, a process interlock is
activated on the conveyor drive changing it to the faulted status and
generating the relevant alarm on the SCADA.
The brake motor JOG mode is disabled if the conveyor is running. The
brake motor LOCAL/MANUAL and REMOTE/MANUAL modes are always
disabled.
Conveyor Brakes
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The belt weighers send a tonnes/hr value as well as other status information to the site PLC system via a Profibus DP
communications link. This link also provides the capability to perform an online calibration of the Belt Weigher.
The belt weigher tonnes/hr and totaliser values are used for the following functions in the PLC control system:
• Reference signals for moisture and iron analysis sensors
• Tracking of ore on the plant conveyors for control of feeders and bin level control systems
• Sample station sequence control
Belt Weightometers
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Status and alarm information is transferred over the communications network between each of the belt weighers and the
PLCs. The main process data reads as follows:
• Instantaneous mass flow rate (kg/hr - Note: translated to t/ph in the PLC) at the belt weigher location
• Totalised tonnage counter value
• Instantaneous mass flow rate at the conveyor head end
• Conveyor belt speed
• Mass value kg/m for moisture analyser interface
This data enables control decisions based on ore movement through the plant to be made by the operator at the control
system. In addition, commands to carry out basic calibration functions of the belt weigher are sent from the PLC. Each belt
weigher provides status information on running and alarm conditions that indicate whether the belt weigher is faulted, or
whether the weighing operation of the belt weigher has been turned on. This status information is used to generate belt
weigher ready and running signals in the PLC so that the PLC can determine whether the operational data read from the belt
weigher is valid for decision-making.
Belt Weigher Operation
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Conveyor Protection Equipment
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The Under speed detection method on most conveyors is
a barrel-type proximity switch that senses a ten flag
target ring mounted on the tail pulley. The Under speed
proximity switch monitors the rotation of the boom
conveyor bend pulley. This ensures that the boom
conveyor and the machine are not overloaded. The belt
speed is monitored ten seconds after starting for motion
(minimum 5% of nominal speed). If it is not achieved, an
alarm is raised on SCADA and the conveyor drive is
tripped. The belt speed is checked fifteen seconds after
the drive starts to ensure the speed is within 85% of the
normal speed. If it is not, an alarm is raised on SCADA
and the conveyor drive is tripped. This occurs in all
modes. During operations, the control system protects
the conveyor from excessive belt slip. If the speed is less
than 87% or more than 115% of its normal speed the
control system:
1. Raises an alarm in the control room to warn the
operator.
2. Trips the boom conveyor drive
Conveyor Underspeed
Proximity Switch
Target Ring Flags
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Belt rip detectors are used to identify loose rubber and/or steel cord wires that could, if not repaired, catch on the
conveyor frame and tear large sections of the belt. Belt rip detectors are located at the head and tail pulley areas of the
conveyor and are “SAFE-T-RIP” type models comprising a heavy-duty stainless steel wire cable with a plug and socket
arrangement at one end. When the cable is struck, the plug is pulled from the socket shutting down the conveyor. Reset
the switch by plugging the plug back into the socket.
Belt Rip Detection
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The belt drift switch is used to ensure that the belt remains within limits that will prevent spillage and damage to the belt
or support structure. Positioned on either side of both the loaded side and the return side of conveyor, the belt drift
switch will trip the conveyor drive if the belt moves across and activates the switch.
The belt drift switch is a small guide roller attached to an arm pivoted on a switch (right). As the belt drifts across it will
push against the roller, which in turn will push the arm. Once the arm has reached the switch limit, the conveyor drive
will stop.
Belt Drift Switch
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WARNING
Electromagnets generate a strong magnetic field that could adversely affect the operation of heart pacemakers or other medical equipment.
Tramp Metal Magnet
Metal from surrounding structures that enters the process stream is
called ‘tramp’ metal. Tramp metal will damage conveyor belts and
other equipment. Large electro-magnets are positioned over the
conveyors and as the tramp metal passes the metal detectors, it
activates the Belt magnet which attracts the metal and discharges it
away from the product conveyor using its own conveyor and
discharge chute.
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Blocked Chute Sensors
Material overflowing from a blocked chute can enter the conveyor tail pulley area or the head pulley area and cause significant
damage to the belt. To prevent this, blocked chute sensors are used to trip (stop) the belt feeding the chute in the event of a
blockage.
There are two types of detectors used on conveyors at Cape Preston
Mercury tilt switch
Explosion door
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Mercury Tilt Switch
The Mercury Tilt Switch is located inside the transfer chute behind the impact plate and away from the ore stream. The mercury
tilt switch is suspended on a chain. If the transfer chute blocks the rising level of ore inside the chute touches and ‘tilts’ the
mercury switch causing the conveyor to trip.
Tilt Switch
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Explosion Chute
The Explosion door is located at the bottom of the transfer chute. If the transfer chute blocks, the rising level of ore in the chute
pushes against the door. A striker plate secured to the door activates the proximity switch as the door opens, causing the
conveyor to trip.
Proximity Switch & Striker
Plate
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Cyclone Tie-Down
WARNING
Starting a conveyor with a Cyclone Tie-Down component holding the belt down will result in significant damage to the belt .
Cyclone Tie-Down equipment are used to
prevent conveyor belts from lifting off the
carry rollers in cyclonic wind conditions.
Wind hoops are positioned above the belt
and are swung down to the centre of the
belt and pinned in place. A counter levered
arm assists in moving the wind hoop.
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Running Checks
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Pre-Start Checks
Prior to any item of plant or equipment being started, checks must be carried out to ensure a safe start-up. The checks ensure personell safety, avoiding
damage to the conveyor and auxiliary equipment.
The pre-start checks include a visual inspection to ensure that maintenance or other shutdown or housekeeping requirements are complete.
Conveyor pre-start checks include, but are not limited to:
• No personnel working on conveyor
• Clear of equipment, tools, rubbish or other obstructions on or near the conveyor
• All safety guards and other protective devices securely in place
• All rope switches reset
• Belt in good repair and centred on carrying rollers
• All belt cleaning devices secure and in place
• All pulleys secure and bearings in good condition
• All inspection hatches closed
• Tracking frames clear of debris and able to pivot freely
• Belt weighers free from build-up
• Belt scrapers in place
• Belt cleaning water sprays on
• Chutes free of build-up
• Where applicable, chute high level probes free of build-up and hanging clear
• Where applicable, chute curtains in good repair
• Counterweights/take-up weights and pulleys have free travel and have guards in place
• Conveyor skirting in place
• Drive system gearbox oil level okay
• Drive system guarding securely in place
• Conveyor(s) de-tagged and de-isolated
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Checks
Operating Checks
Once all the pre-start checks have been completed, ore is then fed into the system. When the conveyor system and
other process systems are on feed, the operator, using both the monitoring system and in field checks, has to ensure
that the conveyor systems have:
Monitoring System Checks
• Sufficient discharge bin levels (note levels to compare with actual)
• Auxiliary equipment such as shuttles ready to feed to the appropriate priority bin
• Upstream processes on feed
• Tonnages on conveyors balance with bin levels and capacities. Allow time for the process to become fully
operational and there is a true flow of ore. Any large discrepancies will require in field investigations- (belt
weighers, speed sensors, belt slipping etc.)
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In Field Checks
• All belts are tracking accurately
• Ore loading onto the centre of the belt- (off centre loading causes belt drift)
• No blockages in chutes or other discharge points
• No tears or excessive wear on belts or delaminating
• Splice not lifting
• No oil leaks from drive systems
• No bearing noise or excessive heat. Most bearings cannot be safely touched to check for excessive heat and
should be left to condition monitoring personnel, however, if you feel heat radiating from the bearing, it is
excessively hot)
• All rollers in contact with the belt run freely - no collapsed bearings
• Wear plates and rock ledges etc. in chutes and hoppers are not excessively worn. Ore spillage is an indicator of
excessive wear
• Belt scrapers secure and working efficiently
• No excessive lagging wear or build up on pulleys (Head, Tail, Bend, Snub, Counterweight, Drive etc). Pulley build-
up can cause belt drift
• No ore contamination (oversize ore, oil, other material etc.)
• Belts not excessively overloaded
• Check idler bearing temperatures
• Check pulley bearing temperatures
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In Field Checks
• Ensure skirting is in good condition (no spillage or belt damage)
• Counterweights/take-up weights are free to travel on slides
• Rail mounted conveyor components have no build up on tracks and can move freely
• Dust suppression/extraction systems are operating efficiently
• Safety guards and protective devices in good condition and securely in place
• Belt weighers free of build up
• Speed sensors (tachometer, vane) rotating freely
• Check temp of bend pulley bearings- drive and non drive ends. If over 50 degrees report to supervisor. Clear off
dust build up on bearings.
• Check bend pulley #8 lagging is secure and no wear grooves.
• Check temp of take up pulley bearings- drive and non- drive ends. If over 50 degrees report to supervisor. Clear off
dust build up on bearings.
• Check take up pulley lagging is secure and no wear grooves.
• Check take up tower weight tracks for build up of product.
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In Field Checks
• Check bend pulley lagging is secure and no wear grooves.
• Check temp of bend pulley #5 bearings- drive and non drive ends. If over 50 degrees report to supervisor. Clear off
dust build up on bearings.
• Visually check gearbox for oil leaks and clean off dust build up around breather and gearbox shafts and seals.
• Check gearbox temperature at output shaft.
• Check drive motor fins are free from build up (10 deg C in temp reduces life of motor by 50%) record bearing temp
- drive and non drive ends.
• Check brakes for build up.
• Check brake hydraulics for leaks and build up on electric motor fins.
The frequency of these checks will be dictated by operating parameters and condition of equipment. Some checks
will require more frequent monitoring.
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Conveyor System Trouble Shooting
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Conveyor Rope Switch Trip
Cause How to Fix
Emergency situation Immediate emergency response procedure, contact security
Spillage from beltCheck belt, re-set rope switch, check for belt overloading or off-loading, drifting
and carry back
Worker accidental grabbing or knocking rope
switchCheck worker safety and condition of belt, re-set rope switch
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Blocked Chute
Cause How to Fix
Foreign material blocking chute (metal,
timber etc.)
Isolate, lock and tag conveyor belt. Clear the chute by digging, crowbar,
air/water spear
Belt tripsStop belt, switch to Local at Stop/Start Station and run to clear blocked
chute. Locate and fix cause of belt drift
Large flat rocksIsolate, lock and tag conveyor belt. Clear the chute with crowbar,
air/water spear, jackhammer
Upstream processes oversize rocks
Isolate, lock and tag conveyor belt. Clear the chute using crowbar,
air/water spear, jackhammer. Advise upstream process operator and CCR
of cause of blocked chute
Wet, sticky oreIsolate, lock and tag conveyor belt. Clear the chute with shovel, crowbar,
and air/water spear. Investigate cause of wet sticky ore
Excessive build-up in chuteIsolate, lock and tag conveyor belt. Clean out chute with shovel, crowbar,
and air/water spear.
“Safety Starts With Me”
Belt Drift
Cause How to Fix
Ore loading off centre onto belt Fix off centre loading (could be partially blocked chute)
Build-up of material on pulleys and or rollers Clear materials from pulleys and or rollers
Seized or worn rollers Isolate, lock and tag conveyor belt and change Roller
Build-up on return side of belt Check belt cleaning devices and adjust as needed
Excessive water on belt Locate source and adjust
Misaligned drive or tail pulley Advise OCC and maintenance personnel
Misaligned counterweight Inspect and free-up counterweight
“Safety Starts With Me”
Belt Tears and Splits
A belt tear is a split that is in the same direction of travel as the belt. A rip is running across the direction of travel of the belt.
Belt tears and splits have the potential to cause spillage and serious damage to belts. Stop belt immediately if it is being
damaged. All tears or splits must be reported to the CCR immediately and the cause identified, where possible. Temporary
repairs can be made using patches or belt clips.
Tears and splits can be caused by:
• Flat rock or tramp metal jammed in discharge chutes
• Falling rock puncturing the belt
• Excessively worn belt
• Rollers worn through creating cutting edge
• Belt tracking into steel supports
“Safety Starts With Me”
TroubleshootingEFFECT CHECK AREA POSSIBLE CAUSE SOLUTION
Belt Damage Longitudinal grooving, gouging oftop cover of belt
Transfer chute Material build-up behind skirt Remove skirts, clean and reinstall
Skirt passing (material rolling under skirt) Adjust or replace skirts
Material build-up in steel skirt area Clean skirt area
Skirt or skirt clamp / bracket dropped down Remove if faulty
Tramp metal caught in impact chute or headchute
Remove and investigate source
Material build-up or foreign body onprimary scraper
Remove and investigate source
Material build-up or foreign body onsecondary scraper
Remove and investigate source
At magnet Trampmetal hung up on magnet Remove
Whole conveyor on return run Seized / missing roller Replace roller
Whole conveyor underneath return belt Material build-up under belt Remove build-up
Counterweight structure Build-up on counterweight Remove build-up
Longitudinal grooving, gouging ofbottom cover of belt
Whole conveyor Build-up on cross beams under carry side(i.e. between carry and return belts).
Remove build-up
At ploughs (return belt scrapers) Rock jammed in plough or damaged plough Remove rock / replace plough
Belt edge rubber damage Whole conveyor Belt rubbing on structure Track belt
Regular gouges on top cover, i.e.regular “cookie-cutter” typepattern
Pulleys in contact with top cover, e.g. bend pulleys atcounterweight, snub pulley/s at drive
Rock caught in pulley lagging Remove rock
Regular gouges on bottom cover,i.e. regular “cookie-cutter” typepattern
Pulleys in contact with bottom cover, e.g. head, tail, driveand counterweight pulleys
Rock caught in pulley lagging Remove rock
Structure under the trough in the loading zone Impacting of the belt onto structure or idlerframe
Repair / modify structure
“Safety Starts With Me”
TroubleshootingEFFECT CHECK AREA POSSIBLE CAUSE SOLUTION
Belt Damage Chatter marks on top cover (corrugatedpattern)
Transfer chute Scraper vibrating and chattering Adjust tension, replace scraper
Belt rip alarm Belting Edge rubber or patch hanging off belt Trim belt / replace patch
Belt delamination Trim delaminated cover
Steel cord protruding Trim steel cord / repair
Tail pulley Material build-up on tail pulley Clean tail pulley
Build-up / Spillage Rubber dust on ground or conveyorstructure
Whole conveyor Seized / missing roller Replace roller
Belt tracked off & rubbing structure Investigate source & track belt
Material build-up under the belt Remove build-up
Foreign body rubbing on belt Remove foreign body
Spillage on floor Transfer chute Skirts worn Replace skirts and remove spillage
Hole in chute Patch chute and remove spillage
Chute overflowing Clean chute and throat (steel skirtarea)
Spillage before discharge due to surge load Adjust load rate and clear spillage
Inspection door not shut Shut door and remove spillage
More at head end, return rollers Scrapers not effective causing “ant hills” Adjust / replace scrapers, removeant hills
Whole conveyor Belt tracking off Investigate source and track belt
Whole conveyor, return rollers Seized return roller Replace roller and remove build-up
Belting Hole / split in belt Repair belt
Excessive material on return of belt Head / launder Head / launder scraper worn or damaged Replace scrapers
Belt wash sprays not working Inspect sprays, water supply,solenoids etc.
Belting Hole / split in belt Repair belt
“Safety Starts With Me”
Troubleshooting
EFFECT CHECK AREA POSSIBLE CAUSE SOLUTION
Excessive Noise Whole conveyor Collapsed roller Replace rollerBelt rubbing Track beltFlat spot on roller Replace roller
Pulleys Pulley lagging worn / damaged Replace lagging / pulley
Motor overload Drive / transfer chute Belt overloaded – too much weight Inspect
Drive Motor worn Replace motorHot motor Hose the cooling finsDropped phase Inspect phase lights on module
panel
VSD tripped Reset VSDBelt slip Tail Material on tail pulley Identify source and rectify
Whole conveyor on return Excessive water on return of belt Reduce / isolate water, drain sumpsetc.
Mud on bottom cover of belt Clean beltSplices and counter weight Insufficient tension Inspect splices and tension belt
Underspeed sensor Faulty Underspeed detector Replace sensorPulleys Worn pulley lagging Replace laggingDrive / transfer chute Overloaded belt Investigate source of overload,
inspect weighers etc.
Chute overflow Chute Material build-up in chute Clean chuteDirty/ damaged / hung-up chute overflowsensor
Clean / replace sensor
Material build-up on steel skirts Clean steel skirt areaUpstream conveyors Overloaded upstream belt Investigate source of overload,
inspect weighers etc.
“Safety Starts With Me”
Quiz
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