Conveyor Operations · Conveyor guarding is the most critical aspect of conveyor safety. Conveyors...

“Safety Starts With Me”

Conveyor Operations


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


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


Conveyor Safety


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


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


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


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


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


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


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


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.


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.


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).


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.


Conveyor Description


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.


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.


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


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


Conveyor Components


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)


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.


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.


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.


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.


Pulleys


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.


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.


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.


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).


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


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.


Conveyor Rollers or Idlers


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.


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.


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.


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.


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.


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


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


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


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


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


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


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


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


Conveyor Protection Equipment


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


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


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


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.


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


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


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


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.


Running Checks


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


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.)


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


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


• Check take up pulley lagging is secure and no wear grooves.

• Check take up tower weight tracks for build up of product.


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


• 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.


Conveyor System Trouble Shooting


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


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.


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


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


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


Material build-up or foreign body onsecondary scraper


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


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


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.


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Conveyor Operations · Conveyor guarding is the most critical aspect of conveyor safety. Conveyors...

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