Pitfalls and the Profits in Quarry Load Out

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Pitfalls and the Profits in Quarry Load Out

by on JUNE 20, 2013

Whitepaper:

The Pitfalls and the Profits in Load outReducetime and increase your profitabilityPrepared for LOADRITE by Michael van Koeverden, QuarryMining Systems Pty Ltd,Australiawww.quarryminingsystems.com.auBackgroundLoad out within any quarry operation is an important stagethat needs to be well designed and considered. There isscope to save time and increase profits by understanding

the specific needs of your quarry weighbridge and stockpileareas and how the interface between these operationsdirectly affects your quarry productivity and profit.

From the time the quarry gates open first thing in themorning to the end of the working day, the handling ofquarry stock is a dynamic and important process thatinvolves many movements of plant and equipment and

many interactions between quarry workers and other staff.

Every time we touch quarry products with plant andequipment it increases costs in wages, tyre wear, fuel spend,machine hours etc. Therefore we need to minimise ourinteraction with quarry products by automating processeswhere possible and when manual processes are requiredunderstanding them fully to maximise production output

and quarry reliability.
http://www.quarryminingsystems.com.au/http://www.quarryminingsystems.com.au/http://www.quarryminingsystems.com.au/http://www.quarryminingsystems.com.au/


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Our quarry customers operate in a highly competitiveenvironment, where margins are tight, and they are veryfocussed on efficiencies in truck utilisation. Hauling

aggregate is most profitable when the trucks are kept full atall times. Back loads on a trucks return journey are notalways available and as a result cartage costs climb rapidlyas the trucks drive empty.

Most contracts/projects are priced on a set number of loadsper day to achieve slim margins to tight construction timeframes. When delays occur, especially within a quarry, this

is seen by our customer as unplanned delay and across ashift or day, may lead to a reduction in the number of loadscompleted and therefore customer revenue is lost.

In the following example we explore the real measurablecosts of longer cycle times within the quarry, expressed in

Australian Dollars (AUD)

The Average cost per kilometre may be broken downapproximately as follows:

Truck Driver hourly rate AUD 1.40 / kmFinance/Lease Cost AUD 0.55 / kmRoad Charges (where applicable) AUD 0.10 / kmFuel AUD 0.70 / kmTyres AUD 0.10 / kmTolls (where applicable) AUD 0.05 / kmTotal Operating Cost (TOC) per km AUD 2.90 /km

Lets say that a15% margin applies on the transport (TOC)of the quarry material supply. The truck transport cost thenbecomes = AUD 2.90 / km * 1.15 = AUD 3.34 / km


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Note: These costs are based on the truck achieving a givennumber of cycles per day. If the number of cycles are notachieved then the costs, especially for the driver will

increase.Lets review the reduced transport margin if a cycle isdropped due to truck delays.

Based on:

a cycle of 60 kilometres return, a truck is expected to undertake 7 cycles during a shift1. Total transport costs payable by client (when 7 cycles arecompleted as budgeted)

= AUD 3.34 / km x 60 km x 7 cycles= AUD 1402.80 /shiftIf due to delays the truck only manages to do 6 cycles:

2. Total transport costs payable by client (when 6 cycles

are completed due to delays)

= AUD 3.34/km x 60 km x 6 cycles = AUD 1202.40 /shiftThat equals a loss in transport cartage revenueAUD1402.80 AUD1202.40= AUD 200.40 /shift

% loss in Cartage Revenue = (AUD 200.40 / AUD 1402.80)* 100= 14% loss

Note: There will be incremental reductions in costs of roadcharges, fuel, tolls and tyres.However the truck operator is losing approximately 14% incartage revenue; which may make the business unprofitableinto the future, due to holdups in load out at the quarry.


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Therefore it is vitally important that cycle times withinquarry are reduced to a minimum.

As indicated in the example above, the cost to the truckoperating company will be approximately AUD 200 whichthey will want to recover back from the quarry operation. Incases where a company owned truck fleet is used forproduct delivery the increase in cycle times directly affectsthe profitability of the operation(s)

Load and haul cycle times are influenced by a number of

factors that need to be considered.

Time in quarryThe average time in quarry is dependent on a number offactors, most of them outside of the control of ourcustomers. Therefore it must be the quarrys task tomeasure time in quarry and put relevant Key PerformanceIndicators (KPIs) on the different elements of this process

with a plan to reduce overall times.

Time in quarry can be broken down into

Truck (TARE) weighed / recorded and travel time torelevant stockpile

Truck waiting to be loaded Truck loaded and application of tarpaulin if required Truck travel to the weighbridge and if required queuing

to be weighed before exiting the quarryStockpile/weighbridge layout reducing

bottlenecksOnce a customer has entered site, effective stockpile layoutwill minimise congestion and time spent in the stockpilearea. Having fast moving products close at hand or easily

accessible will allow for quicker loading; slow movingproducts should be given a lesser priority for position


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within the stockpile area. By having an intuitive layout thecustomer is directed to position their trucks naturally in thebest location for quick load out.

The quarrys stockpiling area should be designed to ensurethat there is sufficient room for mobile plant and customerstrucks to operate effectively. Where possible all vehiclesshould be able to move past each other with sufficient room.Pinch points should be kept to a minimum or designed out.Where there is not sufficient space for this to happen,implementing a one way system can be effective in reducing

vehicles operating in close proximity.

The design of a one way system should be intuitive. Once atruck has passed over the weighbridge and entered thestockpile area, the drivers route around the stockpileshould be easily identifiable. Providing adequate signageindicating direction of flow and general traffic rules assists,as does providing well-planned stockpile layout maps at the

weighbridge and guidance as required.

If there are cross roads where traffic merges, especially atthe weighbridge, this can add to congestion during high orpeak periods. One way systems will reduce congestion atthese points. Where possible the weighbridge should bedesigned so that dockets can be issued via a drive upwindow. This means that drivers do not have to leave theirvehicle to collect their docket which offers advantages bothin terms of reducing drivers time on site, and from a safetyperspective reduces the amount of pedestrian activity in thequarry environment.

Information sharingIn the traditional quarry environment, information sharing

throughout the site is usually done verbally by use of openchannel 2 way Ultra High Frequency (UHF) radio.


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This includes communications between the weighbridgeand the stockpile loud out area and haul trucks. While thissystem is cheap and easily expandable by simply purchasing

more hand held units, it relies on clearly spoken and clearlyheard communications.

Whether it is a bin truck, light vehicle, water cart, haul truckor loader, multiple communications across open 2 waychannels can lead to mistakes where high volume of trafficis experienced. In some cases it may be that the wrongmaterial is loaded out and is picked up at the weigh bridge

where it is returned back to the stockpile area to be tippedoff with the truck re-loaded with the correct product(s).

In the worst case the wrong product may be sent to sitewhere it may be used in the wrong application incurringpotential re-construction costs or it may simply be returnedto the quarry unpaid for. In any of these scenarios thequarry and the customer are losing profit. The importance

of clear and accurate communication can never be over-emphasised.

By adopting electronic technologies these risks may beminimised and ideally with the right balance eliminatedcompletely. If both the weighbridge and the loaderoperators can clearly see individual material productidentification, linked to a visible job number or a customerrequest, and the length of time a customer has been onsiteis visible, the management of time in quarry can bemeasured. If it can be measured it can be managed.

Clear communication between the weighbridge and thestock load-out area is key to ensuring that the correctproduct is loaded and in a timely manner. This can both

reduce the time that customers have to spend on site, andmitigate the risk of communication errors to improve both


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the accuracy and efficiency of the loading process.Dedicate communication solutions may also be soughtthrough loader bucket scales interfacing with the

weighbridge to further remove errors.

Measuring loader performanceLoader performance is a key consideration for operationsmanagement and ideally the loader should be operating atpeak capacity for as much of the day as possible. Howeverwith quarry customer traffic typically varying throughoutthe day, loader usage will also vary. Monitoring loader

performance allows operators and management tounderstand current performance, spot where improvementscan be made and to implement a plan.

Loader Operation Loading PatternsIdeally the loader should be working in a V pattern, movingin and out of the face in loading the truck, and when viewedfrom above creates a V pattern. While this is the ideal, it is

difficult to perform in many cases and relies on loaderoperators understanding of how important it is to load asclose as possible to the v-type optimum. This will ensure theminimum distance is traveled to get the truck loaded and onits way.

Figure 1: V-pattern loading for efficiency

Figure 2~4: V Pattern Loading
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Mobile equipment efficiencyTo ensure a high level of performance, mobile equipmentneeds to be carefully monitored, and for this we refer to a

common manufacturing facility evaluation tool.

How effectively a manufacturing facility is utilised isevaluated through the Overall Equipment Efficiency(OEE) protocol which was first developed in the 1960s andmeasures three factors:

Performance actual throughput vs. target throughput Availability actual plant hours vs. planned plant hours Quality product produced to specification for number

of units produced.Each of the three factors is calculated as a percentage andmultiplied together to give a top line metric. A world-classquarry may achieve 85% or higher in this metric. While amobile plant, involved in load out, is quite different thesame concept can be applied to establish existing efficiency

and work towards improving it. The three measures thatcan be used are availability, utilisation and load accuracyand they are discussed below.

AvailabilityLoaders should achieve key availability targets that relate totheir ability to work as and when required. A high score inthis measure is dependent on the maintenance regime inplace, particularly preventative maintenance. Where thereis no robust plan in place, or the quarry has purchasedproblematic mobile plant (poorly engineered, defective,cheap, and so on) this metric is expected to be low.Availability can also be affected by a shortage of operators.Having correctly trained staff on site and ready to operateequipment is a key day-to-day management issue. A lack of

available operators will adversely affect the availabilitymetric.


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The availability metric is determined by dividing thenumber of loader hours over a determined time period bythe planned number of loader hours required. The result is

expressed as a percentage.

UtilisationUtilisation is the performance of the loader operating in astock storage and load out area. However there are differentways that the metric can be calculated based on access toinformation and key stockpile area objectives.

The simplest way is to monitor the tonnage per hour thatthe mobile fleet has loaded in stockpile area operations. Byrecording the number of hours that loader(s) are working inthe stock area and dividing this by the tonnes sold per day, autilisation metric can be determined. This can be comparedwith the target tonnage for the rated performance of thestock area mobile fleet and expressed as a percentage.

Alternatively, the stock fleet utilisation metric can bedetermined by measuring how the fleet is being operated;including fuel consumption, idling time or other telematicsthat give an indication of how the equipment is beingoperated.

For example, under the Toyota Production System (TPS),idling would be considered wasteful. Beyond loading orunloading, mobile plant should be actively loadingcustomers, carting product to the stockpile (whereapplicable), undertaking housekeeping, or parked up. Idlingreduces overall mobile plant effectiveness and trainingshould be implemented to ensure that it is kept to aminimum.

The results of an on-going focus on reducing idling throughstaff training are illustrated in Figure 1. In early 2009,


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management within a given quarry operation implementeda tracking system to monitor and understand loadereffectiveness. A training plan for loader operators was

implemented as a result which led to a significant drop inidling time in the loader fleet. Over the next two years theidling time gradually increased again, but a renewed focuson idling once again reduced idling times to a targetmaximum of 5%.

Figure 5: Idle Time Monitoring brings benefitTurning off equipment when not in use requires loader

driver education because the prevailing belief is that theconstant stopping and starting of mobile equipment is notgood for general wear and tear. Staff education is vital toprovide an understanding of the real benefits in fuel savingby turning off the loaders instead of idling and theassociated wear and tear issue of loader stop / start.

In addition to the fuel saving benefits of reducing idling

time, there is also a benefit to be gained in plant hire costs.Where units are hired, this should be done on an hourlybasis, and those hours should be managed by parking upwhenever possible in order to reduce hire charges,

Load accuracyThe quarry has a duty of care to ensure that customers

trucks are not loaded beyond the maximum weight they arelegally allowed to carry. Releasing a truck that is overweight
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could have serious consequences for both the quarry andthe customer alike. It is primarily the loader driversresponsibility to ensure that customers trucks are not

overloaded, and in cases where this does happen, the loadmust be unloaded and reloaded. This can cause lengthydelays, especially at peak times.

The TPS would characterise this kind of rework as wasteful.On sites where there are issues with loading inaccuracy,operators should be given additional training/supervisionto increase their success rate. Metrics on

performance should be implemented, and discussed withrelevant staff to ensure that the performance review istransparent. Where it is being monitored there is usually aninitial performance improvement.

Example of mobile equipment efficiencyAssume that Quarry A has 3 loaders operating and has thefollowing targets in place for load out.

Rated hourly capacity of loader fleet of 360 tonnes perhour

Average daily sales of 3,300 tonnes 11 hours per operation Total loader hours of 32 hours. Operator breaks covered Total 112 trucks loaded (29.5 tonne average weight), 3

trucks reloadedAvailability- 32 actual hours / total 33 hours = 97%

Utilisation- 110 tonnes/hour per loader / 120 tonne perhour loader capacity = 92% Loader Accuracy- 109 trucksloaded to correct weight/ total112 trucks = 97%

On this given day the mobile equipment efficiency would be

87%. Typically we would be targeting greater than 85%.


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By implementing a number of the concepts and bestpractice discussed in this white paper you will be able torealise benefits to your operation.

If the stockpile area of your business is not run efficientlythe extra costs may not be immediately obvious to youroperation, but will be for your customers profit. Stockpileareas should be well considered and the loader operatorsunderstand their importance to the load out process.Adopting technologies that limit error in the load outprocess and at the weighbridge will ensure that the right

quantity of the right product gets loaded. This will providegreater returns by repeat business and satisfied customers.

Pitfalls and the Profits in Quarry Load Out

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