Applied ergonomics for operator compartment design in an ... · Applied ergonomics for operator compartment design in an EJC 88 XLP loader The term ‘ergonomics’ was formally established

The Journal of The South African Institute of Mining and Metallurgy VOLUME 106 REFEREED PAPER JANUARY 2006

Introduction

The mining industry in South Africa hasundergone significant changes since the 1980swith increased mechanization anddevelopment of new technologies. Despitechanges, many jobs continue to be labourintensive, physically demanding and repetitive,and human-centred design principles are oftenneglected in the design and development ofnew equipment and technologies.

This research details an ergonomic studyon the operator’s compartment of an EJC extra-low-profile loader (LHD—load-haul-dumpmachine), where human-centred designprinciples are taken into consideration in thedesign and development of this new product. Itis because of the development and evolution ofmechanized, low-seam mining in the SouthAfrican platinum mining industry that theneed for this loader, and thus this ergonomicsstudy, arose.

The market needs for extra-low-profileequipment arose at the turn of the centurywith the platinum industry’s drive towards

mechanization. The detailed market study forthe XLP (extra-low-profile) loader designstarted at the end of 2001, with the conceptdesigns being put forward in mid 2002 andthe actual prototype machines being designed,constructed and delivered by early 2003. Theprototype machines were tested, analysed andperfected until it was deemed a product inearly 2004.

This LHD had to meet the design criteriadetermined by the environment in which it hadto function. With the general consensus, at thetime of design and development, being that themachine had to operate in a stope with a widthof 1.1 m, it was determined that the machinewould be 880 mm high, meaning that theallowable space for the operator’s compartmentwas basically the size of a ‘coffin’. One canconceive that the disregard of ergonomicsprinciples in the design of this cabin could leadto severe operator discomfort anddissatisfaction, or serious bodily injury fromcontinued operation, due to the fact that thisoperator would have to operate this machinelying in a supine position.

Ergonomics

Definition

The aim of defining ergonomics is to create abetter perception of the term ‘ergonomics’, anddevelop a suitable understanding of how andwhy it should be applied to the design ofequipment, products and systems. It alsohighlights the benefits that applyingergonomics principles may have for both theorganization and the individual workers.

Applied ergonomics for operatorcompartment design in an EJC 88 XLPloaderby S. Thorley* and N.D.L. Burger†

Synopsis

In engineering design of operator’s compartments, in undergroundmining equipment, ergonomics principles are often neglected or notgiven the full recognition they deserve. This paper definesergonomics, applies it to machinery in an underground miningenvironment and describes the ergonomics analysis undertakenduring the design phase of an EJC extra-low-profile mining loader.Encompassing the design of the operator’s compartment of this newloader, this paper illustrates the importance of ergonomicsprinciples within the collective design process, ensuring that it isfully integrated into the design approach. An ultimate aim of thisstudy is to ensure that all future designs follow this route toguarantee not only the outcome of a highly efficient, cost-effectiveand productive machine but that it is also takes the human factorinto account, not only in maintenance but also in operation.Maximizing comfort will have the ultimate outcome of actuallyincreasing productivity.

* Sandvik Mining and Construction RSA Pty Ltd.† University of Pretoria© The South African Institute of Mining and

Metallurgy, 2006. SA ISSN 0038–223X/3.00 +0.00. This paper was first published at the SAIMMConference, Platinum Adding Value, 3–7 October2004.

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Applied ergonomics for operator compartment design in an EJC 88 XLP loader

The term ‘ergonomics’ was formally established in 1949by KFH Murrel from the two Greek words ergon, meaning‘work or effort’, and nomos, meaning ‘law or rule’. Literallytranslated, ergonomics means ‘the laws of work’ (Bridger,1995; Galer, 1987; MacLeod, 1995; Murrel, 1965).

The applied science of ergonomics was formallyestablished in the late 1940s. As a science, ergonomicsstudies human capabilities, limitations and othercharacteristics for the purpose of developing human-systeminterface technology. As a practice, ergonomics applieshuman-system interfaces to the design, standardization, andcontrol of systems. Ergonomics promotes human reliabilityand improved health and safety. It ensures that equipment,tasks and the physical work environment are designed totake account of the capabilities and limitations of people.

With the promulgation of the Mine Health and Safety ActREF (Act 29 of 1996) the concept of ‘ergonomics’ waslegislated into occupational health and safety. For the firsttime in South Africa specific reference was made toergonomics in legislation, that is, the application of‘ergonomic principles’. However, the responsibility waslimited to the manufacturers and suppliers of miningequipment (Section 21(1)(c)).

The objectives of ergonomics

The International Ergonomics Association definesergonomics as ‘the scientific discipline concerned with theunderstanding of interactions among humans and otherelements of a system, and the profession that applies theory,

principles, data and methods to design in order to optimizehuman well-being and overall system performance’. Themain objectives of ergonomics are therefore to decrease therisk of injury and illness, to improve worker performance, todecrease worker discomfort and to improve the quality ofwork life.

The aims or objectives of ergonomics are summarized inFigure 1.

The ultimate goal of ergonomics is to improve andmaintain the welfare of the individual worker, while at thesame time improving and maintaining the welfare of theorganization.

Anthropometric data

In order to be able to apply ergonomics principles when doinga design, and to achieve ergonomics objectives, it isnecessary to have an anthropometric database from which towork.

At the time that the study was conducted there was noapplicable anthropometric database available that specificallytargeted the South African mining population, comprisedmainly of the negroid population. A collection of readilyavailable anthropometric data from ARMSCOR primarily, aswell as the American and Chinese population, was thereforecollected and used as an initial basis from which to formulateour own data, in order to ergonomically design the operator’scompartment of the loader. Specific anthropometric data ofthe negroid mining population was also gathered, using asample population of miners currently working in theplatinum mines of the Bushveld Complex, and compiled toobtain anthropometric data for the ninety-fifth percentilenegroid miner.

The study for the design of the operator’scompartment

Previous designs

The second step in the theoretical part of the design of theoperator’s compartment, once the ergonomics study wascomplete, involved the examination and assessment ofexisting underground mining equipment. It was necessary toanalyse previous designs and to understand the issues andproblems experienced in the field with the current operators’compartments. This investigation allowed us to learn fromprevious mistakes, and take this design opportunity toprovide for possible solutions to the identified issues byapplying ergonomics principles.

In order to obtain applicable and beneficial informationfrom this sort of study it was necessary to look atcomparative equipment.

The machines’ operator compartment (Figure 2) wasexamined and assessed according to human-centered designprinciples. The objective of any ergonomic design is toposition the operator’s seat, headrest and armrests tooptimize comfort and health and safety, and also toergonomically place all the operating controls andinstrumentation to maximize operator performance,ultimately promoting human reliability. It can clearly be seenfrom Figure 2 that the design of this operator’s compartmentwas not based on fundamental ergonomic principles.

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44 JANUARY 2006 VOLUME 106 REFEREED PAPER The Journal of The South African Institute of Mining and Metallurgy

Figure 1—The objective of ergonomics (adapted from Wilson andCorlett (1990:6))

Main problems identified during the above studyincluded: positioning of joysticks and levers in relation to‘reach’ and well as armrest support; position and operatingangle of foot pedals in relation to ‘reach’ and with respect toa fixed point of reference, and positioning of the knobs andinstrumentation in relation to ‘reach’ and visibility. Insummation, the workspace envelopes were not adequatelyexamined during the design phase.

Scope

The development and design of the EJC 88XLP loader was acomplete paradigm shift from the normal type of low-profileloader. It involved not only a completely new type oftechnology, but was also far lower than any loader EJC hasever made. The move to extra-low-profile, mechanized,trackless, mining machinery has not yet been successfullyimplemented by the mining world.

It is because of the orebody being much narrower andbecause of the need to maintain low dilution levels, as wellas because of labour issues, safety and a need for increasedoutput and revenue, that low seam mining came about. Andit is from the evolution to mechanized, low-seam mining thatthe need for the EJC 88 XLP developed.

The machine on the drawing board (and as can be seenin Figures 3 and 4) was only 0.88 m in height, which meantthat the operator’s compartment was going to be longer thanit was high (approx. 2 m x 0.5 m). There were, therefore, alot more constraints and limitations that had to be taken intoaccount when designing this operator’s compartment. Theseinclude mining, health and safety, environmental and sizeconstraints (cabin envelope).

In Figures 3 and 4 a dashed, blue line outlines theoperator’s compartment. From these figures it can be seenthat this is certainly not the norm as far as operatorcompartments of mining machinery go because the operatorlies in a supine position, perpendicular to the direction ofmotion, turning his head to the left when driving forwardsand to the right when driving in reverse.

Objective

The objective was to ergonomically design and place theoperator’s seat, headrest and armrests, and also toergonomically place all the operating controls andinstrumentation according to human-centered designprinciples. The ergonomics with regards to the entrance andexit of the machine had to also be carefully considered,because the operator only had a small doorway area as canbe seen in Figure 5. The study had to be undertaken, withinthe capabilities, cost constraints and manufacturing capacityof the product company designing and assembling themachine. The ultimate objective was to design the cabin tomaximize operator performance, while ensuring operatorcomfort, health and safety and promoting human reliability.

Application of ergonomics principles in the design ofthe operator’s compartment

A useful concept in understanding the occupationalapplication of ergonomics is that of an ‘ergosystem’(Galer,1987). An ergosystem consists of three interactingcomponents, namely human, machine or technology, andenvironment (Figure 8).

Applied ergonomics for operator compartment design in an EJC 88 XLP loaderTransaction

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45The Journal of The South African Institute of Mining and Metallurgy VOLUME 106 REFEREED PAPER JANUARY 2006 ▲

Figure 3—Side view of the EJC 88 XLP

1549 mm

General Arrangement

7743 mm

3098 mm 811

mm

897

mm

Figure 2—Example of a low-profile machine

The most general approach to ergonomics is to consider aperson interacting with technology. The interaction occurs bymeans of displays whereby the machine or technologyprovides information to the user and controls and the userpasses information to the machine (Figure 7). There istherefore a complete information flow loop with a properfunctioning of all the parts. In order to ensure successful, safeand effective use, there should be no delays in theinformation flow (Galer, 1987).

The interaction between human and machine alwaystakes place in a certain workspace, which is located in aspecific physical and psychological environment (Figure 8).

The characteristics of the workspace and the environment willaffect the task performance of the human. The workspace, inrelation to this study, is described in terms of the size andlayout of the seat and its accessories, controls and display ofthe operator’s cabin. Factors such as size and layout will havean effect on the body position, body posture and reachdistance of the expected user population, and consequentlyon comfort and efficiency. Entrance and exit from theworkspace (i.e. the cabin) will also have an affect on thehealth and safety of the operator.

The environment can be described in terms such astemperature, lighting, noise and vibration. It can also be


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Figure 4—Top view of the EJC 88 XLP

2133

mm

2488

mm

2108 mm

5902 mm

3237

mm40°

Figure 6—Operator’s compartment of an EJC 88 XLP in operation

Figure 5—EJC 88 XLP in operation

described in psychological terms such as teamwork,management structure, shift conditions and psychosocialfactors, which are beyond the scope of the current research.

When one approaches the design of the operator’scompartment from an ergonomic point of view, all the above-mentioned criteria have to be considered. It can be concludedthat one must initiate an ergonomic study right at thebeginning of a project, to design a new product, and continueit right through the feasibility study, functional analysis,design phase and development of the machine, as well asafter the machine is in production. Ergonomics is an ongoingprocess and can constantly be applied to improve the workingconditions for the operator.

The detail design of the operator’s compartment

Design processThe design of the operator’s compartment started with anextensive ergonomics literature study, as discussed above. Anumber of constraints also had to be taken into accountduring the design of this extra-low-profile loader. Theseconstraints included operational, design and miningconstraints. An anthropometric database was also created inorder to aid in the researcher’s ergonomic design.

This section deals with the design of the operator’scompartment. At this point the design of the machine, as a

whole, was in its preliminary stages. The researcher had tofirstly verify the envelope size and access points, which wasdone by means of using a miniature scale mock-up. Once thiswas done, the machine parameters could be finalized, afterwhich a complete dimensional organization of the cabinterior was done, by means of using a full-scale mock-up.The dimensional organization of the cab interior includesaccess, seating, operator’s posture, layout of the controls anddisplays, and visual fields.

A miniature size, to scale (6:1), mock-up was made ofthe EJC 88 XLP’s operator compartment based on thepreliminary design dimensions. A to-scale wooden manmodel, of the 95th percentile negroid male, was also used toaid in the validation experiment (refer to Figure 9).

The mock-up seen in Figure 9 was made in order todetermine whether the proposed size of the cabin wasadequate for operator access. It was also used to confirm thatthe operator could lie comfortably and operate the machinesuccessfully. It was made as a means to confirm the proposedsize and placement of the entrance/exit and emergency exit.The model man was moved into and out of the cabin byhand, as a means of simulating the operator’s actual bodymotion.

From this investigation it could be concluded that theoperator’s compartment is not only more than adequate insize, but that the size and placement of the entrance/exit and



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Figure 7—Communication between human and machine viewed as an information flow loop (after Galer, 1987:18)

Figure 8—Human-technology-workspace-environment model (Guild, Ehrlich, Johnston, Ross, 2001)

Operator

Machine

InformationReception (input)

InformationIndicator (Output)

Control action(Output) Control mechanism

(Input)

Human Task Technology

Workspace

Environment


emergency exit are also acceptable. The operator’s visibilityfor forward and backward vehicle motion was also seen asbeing adequate.

The preliminary design was therefore approved and thefinal envelope design was then completed. The final designmeasurements were used in setting up the operatorcompartment design parameters.

Once the envelope as well as the entrance/exit sizes andplacement were verified, a full-size, to-scale, mock-up wasmade. It included a seat base and backrest, a headrest,armrests and joysticks. The mock-up was made as a meansof aiding in the design and placement of these items as wellas the instrument panel, helmet and battery pack and basiccabin accessories such as handles (Figure 10).

In defining the design parameters of the cabin (i.e.placement of the seat components, joysticks and othertrimmings), the researcher had to take into considerationease of maintenance, assembly and operation. All themeasurements, used in the design and placement ofeverything in the cabin, were obtained during the literaturestudy. The values obtained during this stage were theoretical,ideal values. During the final design phase these values werealtered and adjusted where necessary to accommodate foractual practice deviations, as well as to make the design morefeasible and thus render it practicable.

If the operator were allowed to remove his belt, with thebattery pack and rescue pack, and his helmet, entrance andexit, as well as normal operation of the machine, would be

made a lot easier. The operator would also experience higherlevels of comfort when seated if he were able to remove hisPPE. The researcher obtained DME concession to remove hisbattery pack and helmet as long as they remain within arm’sreach, but the rescue pack has to be body worn at all times.The ergonomic design of the seat and headrest wasfundamentally based on the fact that the researcher receivedthis DME concession.

Final design

➤ Seat—the seat design included the seat base, seat back,headrest and armrests. The researcher had to designthe seat to provide adequate body support and absorbas much vibration as possible so as to protect theoperator from transmitted vibrations because of theheight constraints in the cabin eliminating the optionof fitting suspension. Unlike a normal seat the backresthas to provide upper arm support because of theoperator being in the supine position and having tooperate the machine using joysticks. In the positioningof the backrest, the joystick-backrest andarmrestbackrest interfaces also had to be considered.The armrests were designed primarily to support theoperator’s forearms while controlling the joysticks. Inpositioning the armrests the backrest-armrest andjoystick-armrest interfaces also had to be carefullyconsidered. The seatback and base were designed to beheight adjustable to allow for different operators to

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Figure 9—Miniature mock-up

Figure10—Full-scale mock-up

Headrest

Backrest

Position for armrest

Seat base

alter their seat positions to maximize visibility, comfortand ultimately productivity. It will also be mostpractical if the headrest, and its mechanism, is fixed tothe backrest, thus moving in relation to the axis of theseat back at all times.Because of the placement of the operator’scompartment, in relation to the direction of travel, theseat and therefore headrest have specific designcriteria. The headrest has to support the head far morewith the operator in the supine position than in anormal sitting-up position. It has to provide completestatic and dynamic head and neck support, as well asallow for movement of the head between the forwardand the reverse driving positions. The headrest has tobe adjustable, along the z-axis, rotationally around thex- and y-axis and in relation to the backrest (y-axis),to maximize comfort for different operators. In order toachieve this desired headrest movement, a specificheadrest mechanism was designed. To satisfy all theabove stated design criteria, a curved headrest on aheight adjustable, swivel mechanism is the bestsolution.This entire seat mechanism was designed for easymaintenance and maximum durability. Theconstruction of the final seat was outsourced, thereforethe final material selection was dependent on what thesupplier had available. The accuracy of the finalmanufactured seat was also reliant on the level of toolsand skills available.

➤ Controls—the controls section initially comprised thejoysticks, pedals, emergency stop, fire suppressionsystem, instrument panel, battery pack, helmet storageand the trimmings, but after field and visibility testinga camera system comprising a screen and two cameraswere added. The positioning of all the controls wasdetermined using functional anthropometric data,obtained during the literature study, and verifiedthrough practical application.

➤ Joysticks—The specific joystick selection was beyondthe scope of this research. The joystick boxes, as wellas their positioning and mechanism for movement,however, had to be ergonomically designed andintegrated by the researcher. The box housing neededto be watertight to avoid any damage to the electronicsof the joystick as well as being as small as possiblebecause of space constraints. The working interfacebetween the operator (i.e. seat) and joysticks had to beconsidered when positioning the joysticks.

➤ Pedals—the choice and placement of the pedals did notform part of the original scope of research, but werepositioned after the machine was built. The design wasoriginally going to incorporate full dual-axis joystickcontrol but was changed at a later stage to include footpedals with the aim of increasing ease of operation forthe operator by eliminating a number of functions fromthe joysticks.

➤ Emergency stop—it is imperative to include theemergency stop as a control in the design of anoperator’s compartment. This hand-activated, push-button is undoubtedly the most important item in theoperator’s compartment and therefore had to be placedsuch that almost instantaneous activation can take

place, both during operation and maintenance. Theresearcher determined that the emergency stop beplaced on the right side of the operator to allow forquick and easy right-hand activation from both withinand outside (next to) the operator’s compartment. Inaddition, another emergency stop was placed at therear on the opposite side of the machine. By havingtwo emergency stops, we are ensuring the safety of theoperator, technicians and bystanders by allowingemergency stop activation to take place from both sidesof the machine.

➤ Fire suppression—the fire suppression system was alsoonly added to the cabin on arrival of the prototype inSouth Africa. Because of the size of the actuator andthe limited available space, it was determined that thebest position for the actuator, to allow for almostinstantaneous activation, is on the left of the operatorbetween the backrest and the cabin sidewall.

➤ Instrument panel—this control selection for theinstrument panel was set, so the researcher had towork with the designated controls. The instrumentpanel and control box placement, either together orseparately, had to be carefully thought through. Adecision-matrix method of evaluation was thereforeused to determine the best place for the panel and boxto be placed. The following selection criteria wereconsidered: available space in the cabin, instrumentpanel envelope, operator visibility, headrest-instrumentpanel interface, operator obstruction, and ease ofmaintenanceAfter looking at the above factors and using a‘decision-matrix’ approach, it was concluded that onthe left of the operator, on the back-side of the mudguard, was the best position for the instrument panel.Once this optimum position was determined, theelectronics technicians designed the layout of thecontrols on the panel and positioned the electricalcomponents. The researcher did, however, stipulatethat the visual display also be fixed at a specified angleto the plane of the face of the instrument panel, basedon the anthropometric visibility data. The instrumentpanel was designed to allow for easy access formaintenance, as well as to maximize visibility for theoperator.

➤ Accessory storage—owing to the fact that the operatorhas DME concession to remove his helmet and batterypack, a storage place for both these items had to bedetermined. After investigating all the remaining spacein the cabin, with the seat and controls in it, there isbasically only one obvious solution as to where thebattery pack and helmet should be stored. They shouldboth be placed on the left of the operator’s legs, in thecentral part of the cabin. A box frame will be weldedonto the inside wall of the cab as a storage place forthe battery pack. There will then also be a hook weldedonto the wall, next to the box, to hang the helmet on.Both the helmet and battery remain within arm’s reach.For maximum operator comfort, once the battery isremoved from the belt, the rescue pack can be movedaround to lie on the operator’s stomach so as tominimize hindrance, between the rescue pack and seat,for the operator.



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➤ Entrance/exit—in order to make the operator’s normalentrance and exit as well as emergency exit of themachine, more comfortable and safe, a number oftrimmings were to be added. Handles were to be addedinto the canopy along the edges bordering theentrance/exit areas to aid in both the entrance and exitof the machine. Another handle was added along the‘lid’ of the centre of the cab to aid the operator whenmoving into his final position after having partiallyentered the machine. Due to time constraints, towardsthe end of the prototype design the canopy was madewithout any added trimmings. After field testing theprototype, in South Africa, handles were added alongthe edge of the canopy to assist with initial entranceand exit into the cabin, as well as along the ‘lid’ of thecentre of the cabin to assist the operator withpositioning himself correctly in the seat.

➤ Camera system—after having assessed the performancein the field and conducting a visibility study, it wasdetermined that in order for the operator to be able toadequately perform his function, a camera systemwould have to be added to enhance visibility andenable the operator to load to his full capacity. Themonitor was positioned in the centre of the cabin,between the forward and reverse head positions, tomaximize visibility and minimize hindrance, withheadrest-camera interface being the most importantconsideration. The camera eyes were placed inpositions that proved to be the most obscured duringoperation—on the right side at the front and on therear left of the machine, for maximum visibility.

FeedbackFeedback was given through to the OEM with the aim of re-applying ergonomics principles to the original design andbettering it to optimize operator comfort and satisfaction. Thefeedback was based primarily on conclusions drawn duringthe trial phase, through practical operations in theunderground platinum mining environment, as well as fromergonomic and brake tests conducted and reported byindependent organizations. An assessment of whole-bodyvibration and noise levels was also conducted.

An operators’ survey was done, by means of aquestionnaire and interviews for feedback purposes. Theoutcome was that the operator’s compartment wascomfortable and that there were no complaints of unusualpain from continued operation. This design was, however, afirst of its kind, and was also made within considerablelimitations, so there will always be room for developmentwhen feedback calls for it. Ergonomics is an ongoing processthrough the research, design, development and utilizationphases of the product, so one can always improve in theefficiency of a design.

Conclusions and recommendations

The aim of this paper was to outline the ergonomics studyconducted during the design of the operator’s compartment ofa new extra-low-profile loader, with the objective of creatinga better understanding of the need and effect of theapplication of ergonomics principles on the design of newunderground mining machinery.

It has become a challenge to give ergonomics higherconsideration during the design of products. In the past,focus has always been on the performance, productivity,efficiency, effectiveness and quality of the machine itselfwhile it was forgotten that improvement in health, safety,comfort, satisfaction and convenience of the operator leads toless absenteeism and labour turnover, more involvement andcommitment and increased motivation and overall well-being, and thus profitability, of the organization.

Complaints, accidents, fatalities, occupational diseases,drops in both productivity and quality, increased runningcosts and a high downtime are just some of the consequencesof the poor design of any product that does not take man andhis role as a factor of reliability and safety into account.

Even though the operator of this machine had to belocated lying down in a supine position, it is through theapplication of ergonomics principles, in the design of thecabin, that the operators now experience a higher lever ofcomfort and satisfaction and in turn generate higherproduction rates and profitability. With the mining conditionsin these low-seam platinum mines being so demanding andstrenuous, all one can do is hope to minimize theseunaccommodating circumstances as much as is practicallypossible and practising ergonomics allows us to accomplishthis.

Although ergonomics is an evolving science, properapplication of its principles can achieve benefits that aresignificant and immediate.

Acknowledgements

The content of this paper was based on a thesis written inpartial fulfilment of a M.Eng. degree with the University ofPretoria. The author would like to thank her University ofPretoria supervisor, Mr. Danie Burger, who activelyparticipated in the progress of the dissertation studypertaining to the subject matter of this paper. The authorwould also like to thank Sandvik Mining and Construction aswell as EJC for the opportunity given to do this study andtheir facilitation in the progress of the thesis.

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GALER I.A.R. Applied ergonomics handbook (2nd edition), London,Butterworth. 1987.

GUILD, E. and JOHNSTON, R. SIMRAC Handbook of Occupational Health Practicein the South African Mining Industry, SIMRAC, 2001. p. 319.

KROEMER, H., KROEMER, K., and KROEMER-ELBERT K. Ergonomics How to designfor ease and efficiency, second edition, New Jersey, Prentice Hall. 2001.

MACLEOD, D. The ergonomics edge: Improving safety, quality and productivity,New York, Van Notrand Reinhold. 1995.

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MURREL, K.F.H. Ergonomics: Man in his working environment, London,Chapman and Hall. 1965.

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Applied ergonomics for operator compartment design in an ... · Applied ergonomics for operator compartment design in an EJC 88 XLP loader The term ‘ergonomics’ was formally established