The organization and management ofa large · tBig Equipment 194 MARCH1975 JOURNAL OFTHESOUTH...

The organization andmechanized colliery

management of a large

by G. C. THOMPSON*, B.Sc. (Min. Eng.) (Witwatersrand), M.B.L. (Member),and P. G. HENDERSONt, B.Sc. (Min. Eng.) (Pretoria), M.B.A. (Member).

SYNOPSISUsutu Collieries Limited, at present the largest single producer of coal in South Africa, supplies Cam den power

station. and produces 435 000 tonnes per month by conventional mechanized methods from bord-and-pillar workingsin three mines. The thickness of the seams averages 2 metres, and the depth below surface varies from 15 to 150metres.

Each mine depends to a different extent on certain common facilities and services. Two of the mines are locatedon the same coalfield, and their rationalization would possibly be advantageous.

Production policy is one of productivity with flexibility. The double-loader system is widely used, and one sectionat each mine is worked on single shift. Pillar extraction is practised where possible.

In addition to lubrication and inspections, planned maintenance of mining equipment consists of sub-assemblyreplacements and overhauls. Conveyor and tractor/trailer transport is used underground. but trolley-wire loco-motive haulage is being considered.

The organization is such that co-ordination is relatively difficult, and certain changes could possibly improve thefunctioning of the engineering and mining departments. Technical and management training is carried out.

Long-term planning will make use of a computer programme and will involve the investigation of other miningmethods. Five-year and twelve-month plans are prepared, the planning of coal quality being based on the viewthat the mine and the power station together constitute a system.

Control information systems make use of a remote computer terminal located at the mine. An improved integratedsystem is being investigated.

SAMEVATTINGUsutu Koolmyne Beperk, tans die grootste enkele steenkoolprodusent in Suid-Afrika, voorsien steenkool aan

Camden kragsentrale en produseer 435000 metrieke ton per maand deur gebruik van konvensionele gemeganiseerdemetcdes in kamer en pilaar werke in drie myne. Die steenkoollae is gemiddeld 2 meter dik en die diepte onderdie oppervlak wissel van 15 tot 150 meter.

Elke myn is in 'n wisselende mate afhanklik van sekere gesamentlike geriewe en dienste. Twee van die myne is opdieselfde steenkoolveld gelee en dit sal moontlik voordelig wees om hulle te rasionaliseer.

Die produksiebeleid is ingestel op produktiwiteit met buigsaamheid. Die dubbellaaierstelsel word tot 'n grootmate gebruik en een afdeling by elke myn word op 'n enkelskofbasis gewerk. Waar moontlik word pilaarafboutoegepas.

Benewens slT"ering en ondersoek bestaan die beplande instandhouding van mynboutoerusting uit die vervangingen opknapping V2n substelle. Vervoerband en trekker /sleepwavervoer word ondergronds gebruik maar vervoermet trollielokomctiewe word oorweeg.

Die organisasie is van so 'n aard dat koordinasie betreklik moeilik is en sekere veranderings kan moontlik diefunksionering van die ingenieurs- en mynbou afdelings verbeter. Daar word tegniese en bestuursopleiding gegee.

Langtermynbeplanning sal van 'n rekenaarprogram gebruik maak en sal 'n ondersoek na ander mynboumetodesinsluit. Daar word vyfjaar- en jaarplanne opgestel; die beplanning van steenkool gehalte behoort van die standpuntuit te gaan dat die myn en die kragstasie saam 'n stelsel uitmaak.

Die beheerinligtingstelsels maak gebruik van 'n afstandsrekenaarterminaal by die myn. Daar word ondersoekingestel na 'n verbeterde ge"integreerde stelsel.

INTRODUCTION

Operations at Usutu CollieriesLimited, at present the largestsingle producer of coal in SouthAfrica, are highly mechanized. Aproduction of 450 000 tonnesper month from bord-and-pillarworkings in coal seams only 2metres thick is possible with a totalmine complement of only 200 Whitesand 1840 Blacks.

Usutu is the sole supplier of coalto Camden, Escom's largest fdly

*General Mining and Finance CorporationLimited (formerly Usutu CollieriesLimited).

tTransvaal Navigation Collieri83/NewClydesdale Colliery (formerly UsutuCollieries Limited).

commissioned power station, whichis situated 20 kilometres south-eastof Ermelo. Installed generatingcapacity at the power station is1600 MW, consisting of 8 sets of200 MW each. The last set wascommissioned in June 1970.

The mine must be able to supplythe station with 435 000 tonnes ofcoal per month, the price per tonnebeing determined on a cost-plus-profit basis. A maximum size ofcoal and a minimum content ofvolatile matter are specified, andpenalties are imposed for low heatvalue and high surface moisturecontent.

Abrasive index and ash-fusiontemperature are important para-

JOURNAL OF THE SOUTH AFRICAN INSTITUTE OF MINING AND METALLURGY

meters of coal quality that affectthe operation of the station.

Usutu Collieries actually consistsof three separate underground mines:West, South, and East. The originalreason for establishing three mineswas to ensure continuity of supplyto the power station in the event ofa possible emergency involving theloss of one mine. By working theremaining two mines for threeshifts per day instead of the usualtwo, the supply of coal to Camdencould be maintained in such anemergency.

During 1972-73 it was decided toenlarge the open stockpile of coalat Camden. The stockpile supple-ments the 100000 tonne capacity

MARCH 1975 193

Target

I

Shuttle

I

CoalMine Production sections tonnejmth Type Loaders cars cutters

West Mine 1 double loader double shift 75000 *Small equipment 2 4 21 double loader double shift 75000 Small equipment 2 4 21 single loader single shift 15 000 Small equipment 1 2 1

---165 000---

South Mine 1 double loader double shift 45000 *Small equipment 2 4 21 double loader double shift 45000 Small equipment 2 4 21 single loader single shift 15 000 Small equipment 1 2 1

--105 000---

East Mine 1 double loader double shift 75000 tBig equipment 2 4 21 single loader double shift 25000 Small equipment 1 2 11 double loader single shift 35000 Big equipment 2 4 2

Double loader double shift}35000 Small equipment 2 3 2Pillar extraction

-170 000

---Spare equipment 5 2 5(including that being

overhauled)TOTAL: 22 35 22

Loader Shuttle car Coal cutter(1) Joy 14 BU 10 llCN Joy 10 SC 15 Joy lORD(2) Goodman 970 Torkar 48AC

Joy 14 BU 10 31BN Joy 10SC l5B Joy l5RUTorkar 52AC

staithes at the station, which arefor short-term production and/orconsumption surges, and for theweekend coal requirements of thestation when the mine is not pro-ducing. The stockpile acts as anemergency reserve and as a bufferbetween mine and power station toreduce the effect of fluctuations indemand for coal by the station. Aminimum emergency level of 150 000tonnes and a maximum practicablelevel of 300000 tonnes were selected.

ARRANGEMENT OF PRODUC-TION UNITS AND SERVICE

FACILITIES

The coal reserves at Usutu coveran area roughly 120 square kilo-metres in extent, which contains anumber of coal seams of varyingthicknesses. For mechanized bord-and-pillar working, the minimummineable thickness is assumed to be1,5 metres at this stage. The field issplit in two by a dolerite sheet, whichis 50 metres thick and overlies the

eastern portion, and which dipsthrough the seam horizon to elevatethe western portion.

The uppermost seam, known asthe B, is developed throughout thefield. Next is the C-Upper, which isof mineable thickness in the westernfield and the northern portion of theeastern field. The least-developedseam, known as the C-Lower, at-tains mineable thickness only inthe south-western portion of thewestern field.

Seam partings are not consistentand vary from less than 1 metre to15 metres. The seam horizon isrelatively deep in the eastern field(100 to 150 metres). Owing to thetopography, the seam horizon inthe western field outcrops in streambeds and deepens to approximately100 metres in the deepest areas.

Location of Mines and Distribu-tion of Production Tonnage

The West Mine, located on thewestern field, is some 5 kilometres

TABLE I

DEPLOYMENT OF PRODUCTION SECTIONS AND EQUIPMENT

from the South and East Mines,which are located close together onthe eastern field. It was originallyintended that the three mines shouldproduce roughly equal tonnages,with the South Mine producingslightly more than each of the othertwo. Exploration by means of under-ground working and the drilling ofboreholes has since revealed thatmineable reserves are now distri-buted as follows:West Mine , 43,5%South Mine

"""""""""

24,1%EastMine

"""""""""

32,4%

At present the three mines areequipped to produce as follows:West Mine. . . . . . 165000 tonnes per

month (37,5%)South Mine. . . . . . 105000 tonnes per

month (23,9 %)East Mine. . . . . . 170 000 tonnes per

month (38,6 %)

The relatively high tonnage beingproduced from the East Mine, thenewest of the three, is due to develop-ment requirements. The arrangementof production sections is shown inTable I.

*Small Equipment

tBig Equipment

194 MARCH 1975 JOURNAL OF THE SOUTH AFRICAN INSTITUTE OF MINING AND METALLURGY

4 24 2

6 or 8 43 or 4 2 or 3

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CommonArrangement ofService Facilities

None of the mines could functionas a separate complete mine sinceeach depends to a different extenton certain common facilities andservices. These common facilities arelocated at the South Mine, whichadjoins the power station.

The following central facilities andservices are used by all three mines:

1. Administration (general mange-ment, secretarial services,accounting and time-keeping)Mine storesHospital for BlacksTraining facilitiesSurveying departmentCentral engineering workshopsand maintenance-planning de-partment.

Facilities shared only by the Southand East Mines are as follows:7. Hostel for Blacks and its associ-

ated administrative services8. Lamp-room9. 5000-tonne coal stockpile and

coal-preparation plant.In respect of hostel facilities forBlacks and the administrative ser-vices associated with them, theWest Mine is independent.

2.3.4.5.6.

Design of the Mines

Shaft SystemsEach of the three mines has its

own vertical upcast shaft and in-clined coal-hauling shaft. At theEast Mine, this inclined shaft is alsoused for all downcast air, men, andmaterial. The West Mine is providedwith a 350 inclined shaft for per-sonnel and downcast air, while theSouth Mine has a vertical downcastshaft equipped with a service eleva-tor.Development and Panel Layout

The layout of the South and EastMines, situated on a common field,is illustrated in Fig. 1. Primarydevelopment for each mine consistsof 18 roads, two sets of 9 roads eachbeing separated by a continuousbarrier, the eventual purpose ofwhich is to separate the main intakeand main return airways of themine. Secondary development iscarried out at intervals of approxi-mately 1500 metres, panels thusbeing worked parallel to the maindevelopment. The purpose of this is

to secure a continuous barrier be-tween the panels and the maindevelopment, which is consideredparticularly important where pillarextraction is practised in panels.

A policy of maximum possiblepercentage extraction consistentwith sound mining practice hasalways been followed at Usutu. Per-mission to extract pillars and toundermine surface structures hasfrequently required protracted andcomplicated negotiations with sur-face owners and with State andProvincial Departments, and suchnegotiations have not always beensuccessful. Where they have been,the mine has been able to demon-strate the ability to achieve in-creased extraction without incident.An example is the successful lower-ing, by pillar extraction, of thesurface occupied by power-linepylons.Ventilation Circuits

Continuous barriers between mainintake and main return airwaysresult in reduced leakage. In thesecondary development and in thepanels, at least two return airwaysare normally carried on each flank.Workings must be ventilated in theinterval between initial mining andpillar extraction. Bleeder entries arenot employed in pillar extraction;

i.e., the goaf is not ventilated,which reduces the possibility ofspontaneous combustion of pillarstumps.Rationalization of South and EastMines

With the change in distributionof the exploitable coal reserves andtherefore of the required productionemphasis, thought has been givento the rationalization of the Southand East Mines. This rationalization,which would require the approvalof Escom, is discussed later.

Mining Methods

Policy.. Productivity with FlexibilityFrom Table I it can be seen that

extensive use is made of the double-loader system, which is more pro-ductive in respect of labour than isthe single-loader system. Utilizationof equipment nominally in use (i.e.,not nominally 'spare') is lower thanit would be with single-loader sys-tems only, but less equipment is idle.

Double shifts are worked as faras possible, but it is policy to workat least one section at each mineon single shift to enable productionteams to work in different sectionsat short notice when necessary. It isalso policy to equip standby sectionswith conveyors so that these can

SECTION LABOUR COMPLEMENTS

TABLE II

Double loader Single loaderPillar extraction(Double loader)

Miner ..Section team leader. . . . . .Safety team leader. . . . . .Loader ................Shuttle car ............Jackhammer ..........Roofbolts installation. . . .Roofbolting machine. . . .Timber support.. . . . . . .Coal cutter ............Duffremoval..........Electricdrill............Blasting ,...Tamping ..............Tailend or feederbreaker

attendant............

Total ................

Miner ..................Rockdrill and roof bolts. . . .Blasting..................Scoopdriver..............


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MARCH 1975 195

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be brought into full production with-in one shift. This flexibility isnecessary at Usutu because of thelarge number of dolerite intrusionsencountered, which would otherwiseadversely affect total production.Double-loader Systems

There are 9 to 17 road ways, 6,5metres wide at ll-metre to 21-metremining centres, that are mined in180- to 250-metre wide panels (Fig.2). A 42-inch or 36-inch conveyor iscarried in the centre road with

complete switchgear on either sideto accommodate the following:

2 loaders4 shuttle cars2 cutters2 compressors3 or 4 electric face drills8 auxiliary fans1 stoneduster.

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breakdowns, machines overlap wherenecessary.

These sections are capable ofproducing between 190 and 250tonnes per hour, depending onequipment, bord centres, and miningconditions. Labour complements areshown in Table H.Single-loader Systems

Single-loader systems are used indevelopment or in remnant blockswhere the limited number of roadsdoes not justify the application of

MARCH 1975 197

the double-loader system (Fig. 3).These sections produce between

90 and 150 tonnes per hour, theoutput frequently being restrictedby the number of working facesavailable. Labour complements areshown in Table n.Pillar Extraction

This method of securing a higherpercentage extraction (85 to 95 percent within panels) of coal reservesis standard practice where possible.It is being carried out in seam heightsthat average 1,8 metres, with an

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approximate depth of cover of HOmetres.

The double-loader system is inuse for pillar extraction. Equipmentis not utilized to the same extent asin normal bord-and. pillar mining,but the availability of this equipmentmakes for a high rate of extraction.Pillars are removed in numericalorder, and in two rows as depictedin Fig. 4.

Two sets of equipment, eachlocated between the panel centreand barrier pillars, are used. Each

pillar is split before the remainingribs of coal on either side areremoved as rapidly as possible, butno pillar is completely split unlessthe adjacent pillar has been re-moved. A production rate of ap-proximately 80 tonnes per hour ismaintained, the labour complementfor a pillar extraction section beingshown in Table n.Stonework

Stonework, i.e. roof or floor brush-ing and development through dykes,is done by one or two teams of 1

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JOURNAL OF THE SOUTH AFRICAN INSTITUTE OF MINING AND METALLURGY MARCH 1975 199

White and 6 Blacks. Rock is loaded,hauled, and dumped by means ofbattery-powered scoops.

Experimentation and Innovation

Hand loading of duff from theface after cutting is a physicallydemanding task, especially in com-paratively low seams, where a largenumber of cuts are made per shiftto achieve the desired tonnage. Tomechanize this operation and toimprove labour productivity, a 'mini-scoop', designed in conjunction withUsutu personnel, was built locallyand is on trial at the mine at present.A belt conveyor that moves on afilm of air instead of conventionalidlers is being developed at the mine,and an 'in-line' coal breaker origin-ally developed at Usutu is being usedon a number of underground con-veyor systems in the industry.

Maintenance of Mining Equip-ment

An effective system of plannedmaintenance is essential to thesuccess of a highly mechanizedoperation, but at the same time it isimportant to avoid costly 'over-maintenance'. The cost problem isaggravated at Usutu by the fact thatthe workings are relatively low and,for the same tonnage as in higherworkings, cutters must make morecuts, loaders must load out morefaces, more flitting must be done,and,because shuttle car payloads arelower, more trips between face andtip are required. The amount ofmaintenance to be carried out istherefore critical. Apart from checksand inspections, a modified 'sub-assembly system' of maintenance isapplied to major mining equipment.This system implies that a machineis 'broken down' into a relativelysmall number of major sub-assem-blies, the bodywork being regardedas one such sub-assembly. For eachof these sub-assemblies, a target lifeis determined, and, when this lifehas been attained, the sub-assemblyis thoroughly examined and, ifnecessary, replaced. If not replaced,it is closely checked until replace-ment is necessary. When the body-work must be rebuilt, the entiremachine is brought to surface. Allsub-assemblies that have attainedmore than 75 per cent of their

200 MARCH 1975

target lives are then replaced, asare others that exhibit undue wear.All sub-assemblies that are replacedeither underground or on surfaceare overhauled in the surface work-shops.

Accurate records of the work doneby each whole machine and by eachsub-assembly are kept by the main-tenance planning department. Targetlives for each type of sub-assemblyare statistically determined but arerevised quarterly on the basis ofrecommendations made by main-tenance personnel to the planningdepartment. Information concerningsub-assemblies is supplied to under-ground foremen every week toassist them in deciding what sub-assemblies should be replaced whenthe monthly machine maintenanceis done. Monthly maintenance, whichalso includes a thorough examinationof the machine and the replacementof the necessary oil seals, etc., iscarried out by a team oftwo fitters,one electrician, and sometimes oneboilermaker for each mine. Theteam is assisted, where possible, bythe artisans in the section on theproduction shift, although sometimesthe work must be carried out inunderground workshops.

Daily maintenance, consisting ofa thorough visual check and therectifying of obvious faults on allmachines in a section, is carried outby the artisans responsible for thatparticular section on production.Where two shifts are worked, eachproduction shift is responsible forlubrication of specific machines.

Overhaul and rebuilding of amachine in the surface workshop in-volves breaking the machine up intoits component sub-assemblies. Theworkshop foremen decide whichsub-assemblies are to be replaced,and the bodywork is completelyrebuilt to the original standard.Electrical work involves the ex-amination, and replacement if neces-sary, of wiring and the overhaulingof switchgear.

Monthly and daily maintenance iscarried out according to schedulesprepared by the maintenance plan-ning department. Major overhaulsare scheduled to fit into the produc-tion pattern and to suit availablelabour and spares, critical-pathscheduling techniques being em-

ployed. to assIst in this. The workperformance of each machine be-tween major overhauls is alsographically represented to illustrateits utilization and to assist in thescheduling of overhauls. The main-tenance planning department alsocontinually analyses the cause ofmachine breakdowns to assist inreducing their frequency.

Transport of Coal, Men, andMaterial

The South and East Mines areequipped with 48-inch main con-veyors, while the West Mine, origin-ally planned to produce not morethan 100 000 tonnes per month, has42-inch main conveyors. To alleviateproblems resulting from the useof 42-inch conveyors, feeder-breakersare being constructed for the double-loader sections. 42-inch secondaryconveyors, and 42-inch and 36-inchpanel conveyors are employed, butthe use of 36-inch conveyors is to bediscontinued.

Battery tractors and trailers areused for transporting material; themain underground roads at U sutuare concreted, and diesel tractors areused to draw the specially con-structed personnel carriers at 25kilometres per hour. Investigationshave been conducted into the feasi-bility of using trolley-wire loco-motive haulage for transportingcoal, men, and material in themain roads of the South and EastMines. This is discussed later.

ORGANIZATION

An abridged form of the organiza-tion chart (for White salaried staffonly) appears in Fig. 5.

Production, Work Study, andMining Training

The Underground Manager, WestMine, in addition to being responsiblefor production from that mine, isresponsible for work study for Usutuas a whole. This is because of thesmall size of the work study depart-ment and because of the relativelysmall scope of his production respon-sibilities. He is also responsible in afunctional capacity for training with-in the whole mining department.The training of Blacks within themining department is the direct


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responsibility of the Training Officer(Mining Labour), who is accountableto the Administration Officer(Labour).

Investigation and Planning

The post of Mining Engineer is adevelopmental one, and the investiga-tions undertaken are those involvingthe interests of Usutu as a whole.These, and the planning, are of along-term (life-of-mine) nature, andthe work is therefore guided directlyby the Mine Manager. In accordancewith the principles of decentralizedmanagement, this investigation andplanning work provides a frameworkfor more specific investigation andplanning by departments, and in noway replaces it.

Engineering Department

The Resident Engineer carriesdirect legal responsibility for surfaceengineering installations, while thecorresponding direct legal responsi-bility for underground is carried bytwo assistant engineers.

The Surface Electrical Foremanand the Surface Mechanical Fore-man are in charge of all surfaceinstallations, except for the WestMine surface installations, includingthe 5-kilometre-long overland con-veyor to the South Mine complex.These are the responsibility of theWest Mine Shaft Foreman.

One training officer is functionallyresponsible for the technical trainingof White artisans in the whole of theengineering department, and theother for the training of artisans'Black aides. White artisans arefully involved in the training ofaides and assist as examiners.

Surveying

In addition to his normal duties,the Mine Surveyor is functionallyresponsible for mine ventilation andstonedusting. His department isresponsible for the necessary ventila-tion measurements and for stone-dust sampling, and he advises pro-duction officials when action isrequired, keeping the Mine Managerinformed as required.

Labour AdministrationThe Administration Officer

(Labour) is specifically responsible

202 MARCH 1975

for the South/East hostel and associ-atOO administrative services, as wellas being generally responsible for thesame facilities and services at theWest Mine, where the Section Ad-ministration Officer is specificallyresponsible. The AdministrationOfficer (Labour) is directly respon.sible for training within the miningdepartment, and the labour ad-ministration department carries outrecruitment, selection, and placingof Black labour for the mine.

Technical Training

Mining Department

A comprehensive set of instruct-ions on all aspects of miningoperations has been drawn up forWhites, all the mining officials beinginvolved in their compilation. Mineoverseers and shift bosses are respon-sible for ensuring that White minersare aware of these and that they areimplemented.

All new Black workers receiveinstruction in Fanakalo, the dis-ciplinary code, and safety and work-ing standards. Their Dudec rating isdetermined by the ClassificationTest Battery.

All of those men that are betweenthe ages of 24 and 45 years undergoa mechanical aptitude test on the'General Mining Battery'* for thepurpose of selecting potential mobilemachine operators, and those whoare successful are allotted to under-ground production sections for train-ing. Basic training begins withinstruction in the handling of cablesand the operation of switchgear.After two days, the learner replacesthe second driver and learns toinspect and operate the machinethat he is normally permitted tocontrol under supervision after oneweek. After a month, the averagelearner is issued with a licence thatpermits him to drive on his own.

Those who are not successful inthe 'General Mining Battery' testare placed according to their poten-tial ability, their own preferencebeing taken into account as far asis possible. They also receive com-prehensive instruction according to

*The 'General Mining Battery' wasdeveloped by Industrial PsychologicalServices (Pty) Ltd especially for theCoal Division of General Mining.

a defined syllabus both from theirown team leaders and from instruct-ors accountable to the TrainingOfficer (Mining Labour).

Engineering DepartmentArtisans undergo one week's full-

time training at the training centreon the surface. This is devoted tothe maintenance of undergroundequipment, with special emphasis,in the case of fitters, on hydraulicsystems. Diagrams and actual com-ponents are used for illustration, butthe most effective training aids areconsidered to be the 16-millimetrecine films made on the mine, forwhich the mine possesses sophisti-cated professional equipment. Forelectricians, particular emphasis isplaced on electrical-wiring diagramsand the tracing of faults. Switch-gear is available in the centre fortraining purposes.

Artisans' aides are selected frommen with a Dudec rating of notmore than 5 as determined by theClassification Test Battery, prefer-ence being given to South AfricanBlacks. Newly-selected aides workas artisans' helpers for two months,after which they spend two weeks inthe training school on the surface.During this time they learn howto inspect and lubricate machines,and how to change wheels, replacedefective hydraulic hoses, and mendbroken flight chains, and so on.

Management Training

The philosophy of decentralizedmanagement is being implementedwithin the General Mining group.Seminars, based on the books byDr W. J. de Villiersl, 2, ManagingDirector of General Mining, areheld at the group training centre atStilfontein. At this stage, practicallyall officials at Usutu have attendedthese seminars. Managers in theGeneral Mining group are also re-quired to attend a 'LeadershipOrientation' seminar, based on theconcept of the Managerial Grid de-veloped by Blake and Mouton3. Inthe Coal Division, this has so farbeen extended to underground-manager level.

Lectures and discussions havebeen started at the mine as thefirst step in extending the pro-gramme of management training.Problems for individual solution and


case studies for group discussionhave both been used, and theprinciples covered in these sessionshave been applied in practice wherepossible.

PLANNIN G

Long-term Planning

Large areas of the coal seams atUsutu cannot be practicably minedby the methods and equipment atpresent in use; nor can they beeconomically mined at present. Newdevelopments could alter the posi-tion to the extent that it may be-come more economical to mine theseareas, thereby limiting geographicexpansion of the workings andexpenditure on services. Owing tomining operations taking placearound them, these areas couldbecome inaccessible with time. It istherefore considered necessary forany long-term plan to allow bothfor flexibility and for the necessityof evaluating alternative courses ofaction at various stages in time.

Although Usutu does not yethave a formal long-range plan, long-term planning has been started bythe assembling of the necessarydata for the PRODUCTION SIMU-LATOR computer programme4,which was developed by the CoalMining Research Laboratory of theChamber of Mines and by the CoalDivision of General Mining. Thisprogramme provides an ideal methodfor the evaluation of alternativeplans.

The two main variable componentsof such alternative plans are:(1) method of mining, and(2) sequence of mining.Alternative methods of mining areas follows:(a) thin-seam bord-and-pillar min-

ing, i.e. below 1,5 metres inheight and with or withoutpillar extraction,

(b) longwall mining, and(c) opencast mining.

The most important output of theprogramme consists of calculatedannual cash flows and the estimatedlife of the mine.

Five-year Planning

A five-year plan for Usutu isprepared before the end of each

financial year in June, the purposebeing to record, for use by manage-ment, the objectives and decisionsbased on the investigations thatbegin not later than April. Theseinvestigations include a review ofperformance in relation to the ob-jectives set the previous year. Theplan follows the form used by themines of the Coal Division of GeneralMining, and includes full revenue,expenditure, profit, and capital bud-gets. It covers production and theutilization of resources such asmanpower, equipment, property, andcoal reserves. Aspects, such as man-power training and development,equipment utilization and mainten-ance, productivity and methods ofincreasing the percentage extractionof coal reserves, receive specialattention, as do topics such asaccident prevention, anti-pollutionmeasures, and proposals for im-proved housing and recreation. Theplan is detailed month by month forthe first twelve months and quarterlyfor the second twelve months, andis presented on a twelve-month basisthereafter.

Production requirements for eachmine are governed largely by thedistribution of reserves but also byother factors such as the amount ofdevelopment necessary, the panelsavailable for pillar extraction, andthe capacities of existing engineeringinstallations. Production require-ments are thus determined by theManager and underground managers,together with the Mine Surveyor andthe Resident Engineer.

For the first twelve months of theplan, the detailed monthly require-ments for underground geographicexpansion are determined by theunderground managers and assistantengineers, together with the mineoverseers and shaft foremen. Labourand ordinary stores requirementsare determined by the mine over-seers and shaft foremen, with partici-pation by shift bosses and foremen.The Mine Manager and the ResidentEngineer are particularly involvedin decisions regarding extraordinaryexpenditure, which requires the ap-proval of the Operations Managerfor the Transvaal Area of the CoalDivision. Underground planning forthe remaining four years is done bythe underground managers, together

JOURNALOF THE SOUTH AFRICAN INSTITUTE OF MINING AND METALLURGY

with the engineers and the MineSurveyor. The whole document iscompiled by the Mine Secretary andco-ordinated by the Mine Manager,with other departments such aslabour administration participatingin the preparation of relevant sec-tions.

A portion of this plan is revisedbefore the end of December eachyear, when a twelve-month plan isprepared. This is found to be mostuseful in practice, since a fairlydetailed plan for just more than sixmonths ahead is available during theperiod when planning is being re-vised.

Twelve-month PlanningProduction requirements are re-

vised, and geographic expansion isrescheduled. Budgets are thus alsorevised. Participation in the prepara-tion of the twelve-month plan is thesame as for the five-year plan.

Monthly Production Planning

Short-term changes are frequentlynecessary because of fluctuations inthe demand for coal and changingmining conditions due, for instance,to the number of dykes intersected.Fluctuations in the demand forcoal can often be absorbed by thelarge moving stockpile, but changingmining conditions require themonthly planning to be done care-fully.

Production targets are set foreach section at the beginning of themonth, and depend on the equip-ment available, mining dimensionsand conditions, and travelling timeto and from the section. The shiftbosses plan the performance andmaterial requirements in physicalunits from this and from the costbudget incorporated in the twelve-month plan.

Extraordinary PlanningRevisions

Fluctuations in the demand forcoal (or in production) can sometimesnot be absorbed by the movingstockpile, and it is necessary to stopor move sections, or to start upadditional sections. It is the pre-rogative of an underground managerto stop or move sections as he con-siders necessary, but the decision to

MARCH 1975 203

commission additional productioncapacity or to reduce productioncapacity must necessarily be madeby the Mine Manager.

CONTROLProduction Control

Production from each mine iscalculated from the conveyorweightometer readings every day.Progressive figures for the month arekept, and weekly outputs are com-pared with targets (production tar-gets are expressed in weekly termssince the mine does not produceduring the week-end, when thepower station is consuming coal).

Figures for the consumption ofcoal by the power station are ob-tained from Camden daily, andprojected burning rates for thefollowing week are obtained at theend of each week. If these differsignificantly from previously sup-plied information, the Manager, afterconsultation with the undergroundmanagers and Resident Engineer,may decide to alter the rate ofstockpiling or reclamation from thestockpile, or to revise productioncapacity. Comprehensive productioninformation for each section isavailable at the end of each monthafter measurement by the surveyors.In the revision of production plans,the policy of productivity withflexibility, coupled with reliabilityof coal supply to the station, ismaintained.

At supervisor level, the standardslaid down in training are strictlyapplied. Because of this and thepolicy described, there has been noneed to 'push for production', evenin the face of heavy and unexpecteddemands for coal by the powerstation. Shift bosses maintain adaily progressive record against planof cars, cuts, and holes.

During the period April 1973 toMarch 1974, the frequency of acci-dents was reduced by 40 per cent.All accidents, after thorough in-vestigation by the officials concerned,are discussed at a meeting of allsenior officials held monthly by theManager, and again at meetings ofall officials held monthly at eachmine by the underground managers.

Records of the work done by themachines and of the maintenancecarried out are compiled by the

204 MARCH 1975

maintenance planning departmentfrom daily reports submitted bymine overseers and shaft foremen.These records provide the informa-tion for control of the plannedmaintenance system already de-scribed. Machine-utilization recordsare used by senior officials to controlutilization and so facilitate correctscheduling of major overhauls.

Cost Control

Changes in the complements ofdepartmental personnel agreed forthe five-year and twelve-month plansrequire the approval of the MineManager. Overtime budgets, basedon the amount of overtime allowedfor in the planning, are preparedmonthly by the officials responsiblefor specific work to be done duringthe following month. The actualtime worked is compared with thisevery week. Daily the shift bossesrecord the physical quantities ofstores consumed and compare pro-gressive totals with a budget for themonth.

True responsibility costing is pos-sible with a system employing anI.B.M. 2780 remote terminal in-stalled at the mine and on-line to theGeneral Mining group system 360computer located at Stilfontein.Daily and progressive expenditureson stores are compared with budgetsadjusted for tonnage; the figuresare available on both a process-centre and responsibility-centrebasis. Aggregated responsibility costsare available for successively higherlevels in the organization.

Extraordinary expenditure, finan-ced through provision accounts toeliminate unrealistic monthly fluctua-tions in working costs, is reviewedmonthly by the Mine Manager andMine Secretary, and is controlledagainst the working cost budget.

Product Quality Control

As far as possible, production isscheduled to give the requiredblend of the important qualitycharacteristics as determined fromborehole analysis. These character-istics (heat value, moisture, abrasiveindex, and ash-fusion temperature)are determined daily by Escom fromsamples of the coal entering thestaithes but, only when a problemarises, are the same determinations

carried out on coal from specificpoints underground.

CONCLUSION

U sutu was the first of the large'captive' collieries to supply Escompower stations of more than 1000MW generating capacity. In somerespects, therefore, the mine was apioneer, and the undoubted successof the operation is due in no smallmeasure to the sound initial planningdone at Head Office and the mine.Experience has since shown certainchanges could be made in methodsand organization that could resultin improvements applicable to theeven larger collieries of the future.

The Three-mine Principle andStockpiling

The South and East Mines couldpossibly be rationalized. Feasibilitystudies have indicated possible largesavings in personnel and in thecosts of services such as power andwater supply, pumping, ventilation,and the conveying of coal, men, andmaterial. The original principle ofthree separate mines is no longerconsidered to be as valid as whenUsutu was planned. Safety pre-cautions based on knowledge arisingout of research and experience haveinvalidated some of the reasons forthe adoption of the original principle.

A minimum stock of 150 000tonnes for emergencies is now main-tained at the power station andcould be increased if necessary.Proportionately far larger stockpilesare being considered for the newestEscom stations.

At this stage it is considered thata suitable output for a singleseparate underground mine supply-ing a power station, either on its ownor in combination with other mines,is of the order of 250 000 tonnes permonth. Subject to considerationof the reserves suitable for methodsof mining other than those at presentemployed, this could be the outputrequired from the South and EastMines together.

In the event of rationalization, itis envisaged that the shafts andmain roads of the South Mine couldbe used for coal hauling, men andmaterial transport, and intake ven-tilation, with the roads and shaftsof the East Mine being used forreturn air.


Mining Methods

It is considered that the outputfrom the PRODUCTION SIMULA-TOR programme should provide agood guide to the selection of futuremining methods. It is thought thatmechanized pillar extraction shouldcontinue as the principal high-extraction method at this stage.However, longwall mining offersdistinct possibilities for thin seamsand seams separated by thinpartings. Because of potentiallyhigher labour productivity, longwallshould also be investigated as amethod to replace the bord-and-pillar system.

Transport Systems

The eastern coalfield at Usutu islong and fairly narrow (roughly 15by 3 kilometres). Two parallel 48-inch trunk conveyor systems servethe South and East Mines. Becausethese trunk conveyor systems willeventually become extremely costlyto operate and maintain, coupledwith the fact that floor gradientsappear suitable for trolley-wire loco-motive haulage, the feasibility ofemploying this method for the mainhaulage of coal, men, and materialwas investigated. Subject to furtherconsiderations such as the implica-tions of multi-seam mining, thereappear to be decided advantages inemploying trolley-wire haulage,especially if the South and EastMines are rationalized.

Organization

The basic organization design atUsutu is traditional and is inheritedfrom other collieries of smaller sizeand different geographical arrange-ment. However, there are manyfunctional relationships, which re-sult from a combination of thefollowing factors:(I) the existence of three mines, two

of which are in close proximityto each other,

(2) a high degree of mechanization,resulting in a relatively smalllabour force, and

(3) the sharing of certain servicefacilities, some by two minesand others by all three.

Co-ordination is hence rendereddifficult, more especially for theactivities of the production andengineering departments. Rational-ization of the South and East Mines

could streamline the organizationto a certain extent, but it is con-sidered that the span of responsi-bility of underground managersshould be extended to cover allunderground activities, includingengineering, on their particularmines. Senior foremen were origin-ally appointed as shaft foremenbecause of the shortage of certifi-cated engineers and because of anattempt to decentralize on a geo-graphic basis. It is considered thatthese men are quite capable ofhandling the normal activities of theunderground engineering depart-ment on each mine, and that theyshould be directly accountable tothe underground manager for this.Only one assistant engineer shouldthen be necessary for the mainten-ance of engineering standards inunderground operations at Usutu.Another newly certificated or partlycertificated engineer could worktogether with the Mining Engineeron special investigations and long-term planning.

It is considered that implementa-tion of the above proposals couldresult in improved integration of theproduction and engineering depart-ments.

A senior personnel officer isto be appointed to be responsiblefor, and to co-ordinate, on a func.tional basis, all personnel activitieson the mine.

Training

Training will be one of the mainresponsibilities of the new seniorpersonnel officer, and it is proposedthat training efforts should be fur-ther intensified: a new trainingcentre is being built, and the trainingof team leaders and artisans' aidesis receiving special attention. Theprogramme of management trainingshould continue to assist in augment.ing management resources for ex-pansion of the Coal Division of theCorporation. A future possibilitycould be the extension of thistraining to miners, artisans, andteam leaders, as is being successfullydone at Sigma Colliery.

Planning

Five-year planning should bebased on a sound long. range plan,and the final four years of the planshould be characterized by a deliber-ate attempt to plan for improve-


ments in methods and increases inproductivity.

Control

Information SystemsThe present management-

information system is not altogethersatisfactory for a number of reasons:(a) too much detail is reported at

too high a level in the organiza.tion,

(b) not enough information is re-corded on a progreesive basisfor periods long enough forthe information to be regardedas representative, and

(c) there appear to be distinctadvantages in regarding theweek, or multiples of a week, as'information periods' (as is doneat present at Sigma Colliery).

Any new information system wouldhave to be integrated with that forthe Coal Division of General Mining;the total system is at present beinginvestigated.Accident Prevention

Additional positive measures toprevent accidents could include(i) the adoption of a formal system

by which potential sources ofaccidents are identified andeliminated, and

(ii) the adoption of a scheme basedon awards for accident-free per-formance by small teams ofworkers such as those in produc-tion sections.

Product Quality ControlThe effect of variations in the

important coal-quality character-istics on the operating costs of powerstations should be positively identi.fied. This should enable betterdecisions to be made, for exampleabout the mining of areas where thecoal quality is not high but whereproduction costs are relatively low.Such information would also be ofgreat value in deciding on the appli-cation of higher-extraction tech-niques, and could be used both in thePRODUCTION SIMULATOR pro-gramme and in shorter-termplanning.

This approach recognizes that themine and power station in combina-tion should be regarded as a system.Changes that are contemplated in theoperation of either should thus beevaluated in the light of theirpossible influence on the system as awhole.

MARCH 1975 205

ACKNOWLEDGEMENTS

The authors wish to express theirappreciation to the management ofthe Coal Division of General Miningand Finance Corporation Limitedfor permission to present this paper,and to thank those members of thestaff of Usutu Collieries Limited and

of the Coal Division who assisted inits compilation.

REFERENCES

1. DE VILLIERS,W. J. Principles ofdecentralised management. Johannes-burg, Federale Mynbou-General Min-ing Group, 1971. 80 pp.

2. DE VILLIERS, W. J. Principles of de-centralised management: supervisory

training course. Johannesburg, FederaleMynbou-General Mining Group, 1972.49 pp.

3. BLARE, R. R., and MOUTON, J. S. Themanagerial grid: key orientations forachieving production through people.Houston, Gulf Publishing, 1964. 340pp.

4. DEIST, H., et al. The development andapplication of a computer system toaid in the planning of production inmines. J. S. Afr. Inst. Min. Metall.,vo!. 73, no. 5. Dec. 1972. pp. 149-160.

Discussion of the above paperH. EASINGWOOD*

The authors are to be commendedon their presentation, with its luciddescription of mechanized coal-production systems in conjunctionwith some pillar extraction. Manage-ment techniques are well coveredunder the headings of Organization,Planning, and Control. It is pleasingto note the significant reduction inaccident incident over a twelve-month period.

The Conclusions and the paragraph

*New Clydesdale Colliery.

entitled Experimentation and I nnova-tion have whetted the appetite formore information. Could more tech-nical information be given aboutthe belt conveyor that moves on afilm of air, and are savings in capitaland operating costs expected withthis system or is it too early to say?

The positioning of 'in line' breakersis of significance - should they befeeder breakers at the receiving endof the conveyor system or withinthe system and, if within thesystem, how frequently are theymoved forward?

An investigation into the use oflocomotive haulage has been made.This is coupled with the rationaliza-tion scheme for the South and EastMines. What hauling distance isrequired before locomotives can com-pete economically with conveyorbelts for main haulage in this longeastern coalfield?

Finally, the suggestion that themine and the power station shouldbe regarded as one unit has merit.Have there been discussions betweena private company and a publicutility on this matter?

Company AffiliatesThe following members have beenadmitted to the Institute as Com-pany Affiliates.

AE & Cl Limited.Afrox/Dowson and Dobson Limited.Amalgamated Collieries ofS.A. Limit-

ed.Apex Mines Limited.Associated Manganese Mines of S.A.

Limited.Blackwood Hodge (SA) Limited.Blyvooruitzicht G.M. Co. Ltd.Boart & Hard Metal Products S.A.

Limited.Bracken Mines Limited.Buffelsfontein G.M. Co. Limited.Cape Asbestos South Africa (Pty) Ltd.Compair SA (Pty) Limited.Consolidated Murchison (Tvl) Gold-

fields & Development Co. Limited.Doornfontein G.M. Co. Limited.Durban Roodepoort Deep Limited.East Driefontein G.M. Co. Limited.East Rand Prop. Mines Limited.Free State SaaiplaasG.M. Co. Limited.Fraser & Chalmers S.A. (Pty) Limited.Gardner-Denver Co. Africa (Pty) Ltd.Goldfields of S.A. Limited.The Grootvlei (Pty) Mines Limited.

Harmony Gold Mining Co. Limited.Hartebeesfontein G.M. Co. Limited.Hewitt-Robins-Denver (Pty) Limited.Highveld Steel and Vanadium Corpo-

ration Limited.Hudemmco (Pty) Limited.Impala Platinum Limited.Ingersoll Rand Co. SA (Pty) Ltd.James Sydney & Company (Pty)

Limited.Kinross Mines Limited.Kloof Gold Mining Co. Limited.Lennings Holdings Limited.Leslie G.M. Limited.Libanon G.M. Co. Limited.Lonrho S.A. Limited.Loraine Gold Mines Limited.Marievale Consolidated Mines Limit-

ed.Matte Smelters (Pty) Limited.Northern Lime Co. Limited.O'okiep Copper Company Limited.Palabora Mining Co. Limited.Placer Development S.A. (Pty) Ltd.President Stern G.M. Co. Limited.Pretoria Portland Cement Co. Limit-

ed.Prieska Copper Mines (Pty) Limited.Rand Mines Limited.

Rooiberg Minerals Development Co.Limited.

Rustenburg Platinum Mines Limited(Union Section).

Rustenburg Platinum Mines Limited(Rustenburg Section).

St. Helena Gold Mines Limited.Shaft Sinkers (Pty) Limited.S.A. Land Exploration Co. Limited.Stilfontein G.M. Co. Limited.The Griqualand Exploration and Fi-

nance Co. Limited.The Messina (Transvaal) Develop-

ment Co. Limited.The Steel Engineering Co. Ltd.Trans-Natal Coal Corporation Limit-

ed.Tvl Cons. Land & Exploration Co.Tsumeb Corporation Limited.Union Corporation Limited.Vaal Reefs Exploration & Mining Co.

Limited.Venters post G.M. Co. Limited.Vergenoeg MiningCo. (Pty) Limited.Vlakfontein G.M. Co. Limited.Welkom Gold Mining Co. Limited.West Driefontein G.M. Co. Limited.Western Deep Levels Limited.Western Holdings Limited.Winkelhaak Mines Limited.

206 MARCH 1975 JOURNAL OF THE SOUTH AFRICAN INSTITUTE OF MINING AND METALLURGY

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