CementEngineers' HandbookOriginated LabahnFourthEnglishedition . KohlhaasandU. Binder . BomkeG.Funke . . Klein-Albenhausen . f lF. MechtoldD.OpitzG. SchaterH.-U. Schater . SchmidtG. Schmiedgen . Schneider . Schuberth . Schwake . SteinbiBH.XellerTranslated . vanAmerongenfromthesixthGermaneditionBAUVERLAG GMBH WIESBADEN ANDBERLINCIP-Kurztitelaufnahme derOeutschenBibIiotheklabahn, Otto:Cement engineers' handbook/ originated OttoLabahn.Transl. vanAmerongenfromthe6. Germaned. - 4. Engl. ed. / Kohlhaas. . , - Wiesbaden;Berlin:Bauverlag, 1983.Ot. Ausg. u.d. Labahn, Otto: Ratgeber furZementingenieureISBN3-7625-0975-1NE: Kohlhaas, Bernhard First edition OttoLabahn, 1954Secondrevisededition OttoLabahn, 1965Thirdrevisedandenlargededition W. Kaminsky, 1971Forthedition Kohlhaasand16other authors, 19831983BauverlagGmbH, WiesbadenandBerlinPrinted WiesbadenerGraphischeBetriebeGmbH, WiesbadenandGuido Zeidler,WiesbadenISBN3-7625-0975-1PubIisher's forewordSincethe pubIication of the first edition of "Cement Engineer's Handbook"28years ago,thisbook has gainedanestabIishedreputationas"Labahn"in thecement industry. In its conceptionit hasits originalauthor. In formandcontentsit hasbecomeanentirelynewbook, however. Thischange reflects thegreattechnical developmentsthat havetakenplaceincement manufactureinthe years.Thefirst editionwas, withtheexceptionof thechapter quarrying, writtenentirely OttoLabahn. ThefullyrevisedfourthGermaneditionof 1970wasstill withintherange of oneindividual author, WilhelmAndreasKaminsky, whoundertook the revision. When it was decided to produce the present sixth edition,it soonemergedfromthepreliminarydiscussionsthat inthisageof specializ-ationthepreparationof thenew text for book of thisscopewouldhave to entrusted to team comprisingauthors from wide variety of technologicai dis-ciplinesassociated withcement manufacture.Inthis effort wehavebeenfortunateinhavinghadtheservicesof BernhardKohlhaasas editor, co-ordinatorandauthor. provedindefatigabIeinseekingsuitabIeco-authorsfor thisproject andhehimself undertooktherevisionof number ofthemanuscriptssupplied. Theseduties made greater claims uponhis timeand attention thanhadbeen expected.We indeedgrateful tohimfor hisunflaggingdevotiontothetask.Theguidingprincipleofthisneweditionisthesameasthat which Kaminskyenunciatedintheprefaceto theeditionwhichhehadrevised:Thesubject matter of thebookas wholecorresponds approximatelytotherangeofprobIems whichconcerntheengineerengagedinpresent-day cementmanufacturingpractice. Theguidingprincipleremains: topresent all that ises-sential andimportant in convenientlyassimilabIeform. At thesametime,thisapproachrulesout anyverydetailed treatment ofindividual subjects.BauverlagGmbHBiographical notes theauthorsIng. UlrichBinderBornat Helmstedt in1946. From1967 to1971, studiedat theStateCollege forConstructional Engineering, Huttental-Weidenau, specializingin the process gineeringof therockandmineral productsindustry. Project andcommissioningengineer with the firmof Gebr. Hischmann, 1971 to 1977. Commissioningengineer with & Orenstein&Koppel AG, Ennigerloh, 1977 to1981. Since1981, headof theprocessengineering, pilot plantsand laboratorydivisionof& Ennigerloh.Address: &Orenstein&Koppel AG, 4722Ennigerloh, W. Ger- ErichBomkeBorn at Beckumin 1923. Studied mechanical engineeringandeconomicsattheTechnological Universityof Karlsruhe. In1953, full partner andtechnicalhead of the Bomke & leckmann cement works (Iater renamed Readymix Zement-werkeGmbH& KG)at Beckum.Supervisory board member of that 1974 to1977. Member of the"Process engi(1eering"committeeof theGermanCementWorks' Association. PubIications.Address: Sonnenstrasse18,4720Beckum, W. Germany.Obering. GerhardFunkeBornat Bremen in1924. Studied mechanical engineeringat the EngineeringCollegein that city. From 1950, five years'service as production engineer at twocement works. Head of the air pollution control divisionin theResearchInstituteof theCement Industry, Dusseldorf, since1955. PubIications.Address: Flandrianstrasse24, 5653Leichlingen, W. Germany.Heinrich Bornat Gelsenkirchenin1934. Studied at theEngineeringCollege at Kiel. From1960 to 1975, staff member and technical head of the pit and quarry engineeringdivisionof plantengineeringfirm. Since1976, partnerandtechnical directoroftheengineeringfirmof IBAUHAMBURG, Hamburg, anditssubsidiariesinParisandNewYork.Address: Leinpfad33, 2000Hamburg60, W. Germany.Prof. Dr. rer. nat. Dietbert Bornin1936. Studied science(mineralogy, chemistry, geology), takingdoctor'sdegree in 1962. Several years as head of department in the construction materialsindustry(concernedmainly withcement researchandconsultancy). From1969to1978, headof thelaboratoryfor constructional chemistryat theUniversityof Siegen; then, 1978 to1980,attheStuttgart University of Technology. Since1980, headof thelaboratoryfor constructional andmaterialschemistryat theUniversltyof Siegen (principal fieldsof work: mineral materials, attackof vBiographical notes theauthorsterials, conservationof buildings); professor at theUniversities of Karlsruhe andMarburg; chairman or member of several workingcommittees; swornexpertfor constructional chemistry (materials, corrosion, conservation of buildings).Pu ications.Address: Hermann-Pleuer-Strasse18, 7000Stuttgart 1, W. GermanyObering. BernhardKohlhaasBornat BadGodesbergin1911. Studiedgeneral electrical engineering. From1932to1954, productionengineer, subsequentlymember of technical centraldepartment of PortlandZementwerkeHeidelbergAG; seniorexecutivein1948andappointmentas chief engineer. From1954 to1975, headof the designandsales department for cement works installations with Humboldt Wedag AG,Cologne; appointment to seniormanagerial statusin1960.Address: Gartnerstrasse1, 7290Freudenstadt, W. GermanyDr. Mont. Fritz MechtoldBorn at Monchengladbach in 1928. Studied mechanical engineering at the Tech-nological Universityof Aachen. Tookdoctor'sdegreeinminingtechnologyatthe Universityfor Mining Engineering, Leoben. Since1955, staff member ofAUMUND-FordererbauGmbH, Rheinberg; nowtechnical directorof thatfirm;accreditedexpert liftingandhandlingappliances. PubIications.Address: Heinrich-Doergens-Strasse 9,4150Krefeld1, W. GermanyDr. Dieter Opitz at Chemnitzin1935. Studiedengineeringmaterials technology for timeattheUniversity for BuildingConstruction, Weimar, thengraduatedinrockandmineral products technology at the Technological University of Aachen(Springormmedal). From1963 to1973, intheResearchInstitute of theCementIndustry, processengineeringdivision, Dusseldorf. Tookdoctor'sdegreeinthefacultyformining, metallurgical technologyandmechanical engineering. Tech-nological Universityof Clausthal (subject: 'Thecoatingringsinrotarycementkilns") in 1973. Since 1974, head of department for fuel and power in thetechnical divisionof RheinischeKalksteinwerkeGmbH, Wulfrath.Address: RheinischeKalksteinwerkeGmbH, Wilhelmstrasse77, 5603Wulfrath,W. GermanyDipl.-Ing. Dr. Gernot SchaterBornat Lubeckin1939. Studiedminingandeconomicsat theTechnologicalUniversity of Aachen, where hetook hisdoctor'sdegree in economics. Since 1974,managingdirector of Beumer Maschinenfabrik KG, Beckum, andof thesub-sidiariesintheU.S.A. andFrance. PubIications.Adress: Beumer Maschinenfabrik KG, Oelderstrasse 40, Beckum, W. Ger- Biographical notes theauthorsDr. nat. Heinz-UlrichSchaterBorn at Bietigheim, Wurttemberg, in 1949. Studied geology at the TechnologicalUniversityofClausthal,wherehe tookhisdoctor's degree. From1971to1974,engagedinbasic geological research; then two yearsinfieldexploration of rockandmineral deposits. Since1976, with DHumboldt WedagAGasprocessengineer for rawmaterialspreparationandfor thegeochemical assessment ofrawmaterialsforcement manufacture.Address: Pastor-Loh-Strasse3,4018Langenfeld, W. GermanyIng. DietrichSchmidt at Radebeul, Saxony, in1933. From1954to1960, staff member inthechemico-mineralogical department of theResearch Instituteof theCement dustry, Dusseldorf. Then head of laboratoryat cement works at Wetzlar andHardegsen; studied chemical technology side side with his professional duties.Since 1979, works manager of theHardegsen cement works of Nordcement AG,Hannover.Address: Sonnenberg16, 3414Hardegsen, W. GermanyObering. Gunter Schmiedgen atLeipzigin 1935. Studied electrical engineering. Since 1955 withthe firmof Siemens, where, since1972, hehas inchargeof thedepartment forprocess engineeringandautomationfor thecement industry. PubIications.Address: Heuschlag21,8520Erlangen, W. GermanyDipl.-Ing. Horst SchneiderBorn at Schlaney in 1925. Studied mlnlng engineering at theTechnologicalUniversity of Aachen, 1949 to 1954. Then assistant in that University's Institutefor PreparatoryProcessing,Coking andBriquetting. From 1959 to 1961, head ofthe cement department inthe experimental division ofFriedr. KruppMaschinen-undStahlbau, Rheinhausen. From1961to1969,scientificstaff member inthedepartment for plant engineering inthe Research Instituteof theCement dustry, Dusseldorf. Then technical director of the engineering firmof Gebr.Hischmann, 1969to1977. Since1977, technical directorof & Orenstein& AG, Ennigerloh. PubIications.Address: &Orenstein & AG, Postfach 25, 4722 Ennigerloh, W.Ger- Dipl.-Ing. BergassessorHermannSchuberthBorn atKulmbachin1934. Studiedmining at theClausthal Academy of Mining.Major government examination1962. Since1963, with RheinischeKalkstein-werke, Wulfrath, initiallyasassistanttotheworksmanagement, theninchargeof opencast miningandpreparationengineering; senior departmental headforprocessingandplanning, alsoactingworksmanager, inthat firmsince1974.Address: Metzgeshauser Weg21, 5603 Wulfrath,W. GermanyVIIContentsBiographical notes the authorsObering. Paul SchwakeBorn in1924. Studied mechanical engineeringat theGovernment School ofEngineering,Konstanz. From 1949 to 1957, designer with firm at Krefeld.Since1957, designer anddevelopment manager of Haver &Boecker, Oelde, wherehehas headof the researchanddevelopment department withtherankofchief engineer since1968. Appointment toseniormanagerial statusin1976.Address: Mozartstrasse12, 4740Oelde 1,W. Germany . Introduction. . Kohlhaas . Rawmaterials. 3Dipl.-Ing. EberhardSteinbissBorn at Wiesbaden in 1941. Studied general mechanical engineering at the Tech-nological Universityof Darmstadt. ' 1969, scientificstaff member inthe searchInstitute of the Cement Industry,Dusseldorf. With Humboldt WedagAG, Cologne, since1982. PubIications.Address: UerdingerStrasse25, 4000Dusseldorf 30,W. GermanyDipl.-Ing. Horst l l Bornat Biberach/Riss in 1935. Studiedmechanical engineeringat theTech-nological Universityof Stuttgart. Since1960, productionengineer invariouscement worksand inthethermal engineeringsectionof thecentral technicalofficeof Heidelberger Zement. PubIications.Address: larchenweg 1,6906leimen,W. Germany1. Geology, raw material deposits, requirements applicate to the deposit,exploration of the deposit, boreholes, evaluation of borehole re-sults,calculationof reserves. . . . . . . . . . . . . . . . ... 3 H.-U. Schafer1 Rawmaterials andquarryingmethods. 42 Exploration 6References . . . . . . . . 2511. Quarryingthe rawmaterials . 27 . Schuberth1 Guidelines for quarrying 282 Overburden. . . . . 303 Breakingout the rock 324 loading . . . . . . 465 Haulage . . . . . . 506 Mobile crushingplants. 557 Siterestoration 57References . . . . . . . 62111. Rawmaterials storage, bIendingbeds, samplingstations. . Schmidt1 Introduction. . . . . . . . . . . . . . . .2 BedbIendingtheory. . . . . . . . . ...3 Machinery andprocessengineeringmethods.4 Sampling stationsReferences . . . . . . . . . . . . . . . . .6465667393100 . Cement chemistry- cement quality. . . . . . . . . . . . . . . 101 . f lVIII1.11. istorical introductionRawmaterials andtherawmix103105' ContentsContents1 Rawmaterials . 105 4 Supply andidentificationof cements 1632 Rawmix: proportioningandanalysis 109 5 Quality control 165References119 6 Suggestions for theuse ofcements 165References 166111. Chemical, physical andmineralogical aspects of the cement burningprocess.119 Cement testing 1661 Drying 121 1 Fineness 1672 Dehydrationof clayminerals . 121 2 Setting times 1683 Decompositionofcarbonates . 122 3 Soundness 1684 Solidreactions(reactions below sintering). 123 4 Strength 1695 Reactionsin thepresence of liquidphase(sintering) 123 5 Heat of hydration 1696 Reactionsduringcooling . 124 References 1707 Factors affecting theburningprocess 125 CementStandards. 170References 128 References 171IV. Portlandcementclinker. 1281 Clinkerphases. 128 Manufacture of cement. 1772 Judgingthequality of clinker. 133References 137 1. Materialspreparationof cement . 179V. Finishgrinding 137 Schneider andU. Binder1 Thematerialsinvolvedinfinishgrinding. 137 1 Primaryreduction 1792 Fineness andparticle size distribution 141 References 2133 Mill atmosphere. 142 2 Size classification 2144 Grindingaids 144 References 238References 145 3 Grinding 239References 266VI. Storage of cement . 145 4 Rollermills 2661 Storagein thecementworks 145 References 2762 Storage theconstructionsite 146 5 Grindinganddryingof coal 277References 146 References 293VII. Hydrationof cement (setting, hardening,strength) 146 11. Rawmeal silos 2951 General. 146 2 Hydrationof theclinkerphases. 1493 Hydrogenof slagcementsandpozzolaniccements. 153 1 General. 295References153 2 Batchwisehomogenization. 2953 Continuous bIending. 297VIII. Relations between chemicalreactions, phase content and strength of4 Combinedsystems. 304portlandcement . 153 5 Summary. 304References 158 References 305IX. Types, strengthclasses, designationandquality control of cements. 158 111. Cement burningtechnology. 3071 General. 158 1 Kilnsystems. 3072 Classificationanddesignationof cements 160 SteinbiB3 Constituents of cements . 163 References 319 Handlingandfeedingsystems- Continuous conveyors. . . . . . 515 F. MechtoldContents2 Preheaters andprecalcining. Steinbir..References . . .3 Clinker cooling XellerReferences . . .4 Firingtechnology Steinbir..References . . . .5 Refractorylinings OpitzReferences . .320326328417421440442458F.1.3 Loadingof clinker andcrushedstone4 "Bigbag"despatch . . . . . . . .5 Shrinkwrapping. . . . . . . . . .6 Automationof despatchprocedures.References . . . . . . . . . . . . .General introductionContents503503506512512515IV. Clinker storage. Kohlhaas1 General .2 Forms of constructionandspace requirements .3 Selectioncriteria. . . . . . . . . . . . . . .4 Design .5 Fillingandemptyingsilos andother storage structures6 Storagebuildings andoutdoor stockpilesReferences .V. Cement silos. 1 General .2 Large-capacitysilosReferences . . . . .45945945946346446546547147247247247611. Belt andbandconveyors .1 Belt conveyors . . .2 Steel bandconveyors111. Bucket elevators. . . .1 General explanation .2 Belt bucket elevators.3 Chainbucket elevators .4 Swingbucket elevators.IV. ChainConveyors. . . . .1 Flight conveyors. . . .2 Continuous-flow conveyors3 conveyorsV. VibratoryconveyorsVI. Screw conveyors..516516523523523525529535539539541543550556 1.Packingandloadingfor despatchPacking .... Schwake1 Introduction.2 Types of packaging477477477478VII. PneumaticConveyorsVi 11. Feeders. . . . . . . Weighingequipment .References . . . . .55957057858211. Despatchofcement . Bomke andG. Schafer1 Despatchinsacks. . . .2 Bulkloading . . . . . .490490495G. Process engineeringandautomation. . . . . . . . . . . . . . . 585 G. Schmiedgen1. General............................ 585 Contents Contents11. Measurement andprocesscontrol .1 Measurement . . .2 Closedloop control . .586587591 . Workshopsandspareparts store . Kohlhaas.. 709111. ProgrammabIecontrollers.IV. Monitoringandoperation.596600L. Water supply,compressed air. . . . . . . . . . . . . . . . . . 717 . KohlhaasV. Process computers. . . .1 Development anduse of process computers2 Computerizedcontrol centre3 Hardwareandsoftware.4 Microprocessors. . .VI. Process control system.References . . . . . .6056056086126136146191. Water supply forcement works1 Estimatedquantitiesrequired .2 Rawwater .3 Supplysystem.coolingwater circuit, water storage .4 Wastewater disposal11. Compressedair supply .717717719720722722 . Environmental protectionandindustrial safety . . . . . . . . . . 621 G. Funke . Personnel requirements. . . . . . . . . . . . . . . . . . . . . 725 . KohlhaasLubricants,storageandconsumption . . . . . . . . . . . . . . 729 . Kohlhaas1. Environmental protection.1 Preventionof airpollution2 Noise control . . . . . .3 Groundvibratio!1sdue tobIasting .References . .622622658680685N.1. General .... 72911. Industrial safety1 Accidentpreventionregulations.2 Promotionof safetyincementworks3 Safetyru les.References . . . . . . . . . . . . .68868869069269311. Types oflubricants.111. Storage of lubricants.1 Deliveryandhandling2 Storage .3 Issue of lubricants toconsumers4 Distribution of lubricants to themachines730730730734741742695695696697704J.1.Maintenance andwear. . . . . . . . . . . . . . . . . . . . . 695 . KohlhaasMaintenance . . . . . . . . . . . .1 General .2 Spares andrenewabIepartsplanning3 Determining thecost ofmaintenanceReferences . . .IV. .Lubricants consumptionReferences . . . . . .Firefightingequipment . . Kohlhaas74374374411.XIVProbIemsof wearReferences . . .705705 . Laboratoryequipment . . . . . . . . . . . . . . . . . . . . . 749 . KohlhaasXVContents . Introduction1. Introduction . 749 . Introduction11. Proposedoutlinespecificationforequipment of individual rooms. 752 . KohlhaasV. Chemicals......... 779IV. General laboratoryapparatus 771111. Laboratory equipment withapparatusandmeasuringinstruments. 761Subject Index. . . . . . . . . . . . . . . . . . . ...XVI..... 785The first edition ofthe Cement Engineers' Handbook was pubIished in 1954. Uptothat time suchreferencebook for theengineer or technicianincement workspracticehadbeenavailabIe. Althoughfour subsequent editionsappeared, thedemand for the book continued as brisk as ever. The major developments that hadmeanwhiletakenplaceinthecement industryinGermanyandothercountriesjustifiedthedecisiontoproduceanentirely neweditionthat wouldtakedueaccount of thelatest cement manufacturingtechnology.Thetext for this newedition has been written teamof experts intheirrespective fields of specialization relating to cement manufacture and themachinery usedat all stagesof theprocess. Someof thechaptershavebeensubstantially enlarged andupdated from those contained in the earlier editions ofthe Handbook. number of new chapters have moreover been added. The entiresubject matter has been extensively recast and rearranged, as will apparent fromthecomprehensivetabIeof contents. Eachchapter isaccompanied list ofliterature references enabIing the reader to consult detailed pubIishedinformation matters of particular interest to him. Thenames of the authors givenatthebeginningof thechapters.Thefollowinginformation thesectionsandchaptersinto whichthebookisdividedwill helpthereader tounderstanditslayoutandtouseit withgreaterconvenience. . Raw materials1. Geology, raw material depositsThis section is of especial significance in connection with setting up new cementworksandensuring long-termsupplyofgood-qualityrawmaterials.11. Quarrying theraw materialsThemoderntechniques of winningtherawmaterials quarrying miningoperations described. The restoration of worked-out quarry sites in the interestsof landscapeconservationalsoreceivesattention. . Raw materials storageTherawmaterialsneededfor cement manufactureare seldomfoundin theidealchemical compositionin their natural state.Besides, quarrying operations usuallystopattheweek-ends, whereascement productionproceedscontinuously. withthehighproductionratesof moderncement plantsandkeepthemsupplied with materials, capaciousintermediate storage facilities required,soas tomake theplantsindependent of thequarryoperatingrhythm. . Introduction . Cement chemistry- cement qualityAfter presenting historica/ introduction, the author of this section deals in detailwith the cement rawmaterials, their suitability and the calculationof the rawmixproportions. The chemical, mineralogical andphysica/ processes associated withburningthematerialsinthekiln described.Portlandcement clinker andtheassessment of itsquality discussed. Othersections deal with cement grinding, storage and hydration. The types and strengthclasses of cement, as well as cement testing procedures and associated matters, also considered. Finally, some information standardspecifications for cementinvariouscountriesisgiven.These matters dealt with much morefully than in earlier editions of theHandbook, with theobject of givingthemechanical andelectrical engineers(including those concerned withprocess control and instrumentation)in cementmanufacture betterunderstandingoftheprobIemsinvolved. . Rawmaterials 1. Geology, deposits . Raw materials1. Geology, raw material deposits, requirements l i to the deposit,exploration of thedeposit, boreholes, evaluation of boreholeresults,CalCiJlation ofreserves H.-U. SchaferD. CementmanufactureThis chapter is devoted to the actual process of making cement. The various stages described. The wet process and the shaft kiln only briefly considered. theother hand, thedry processwith rawmeal preheatingandtheprecalcinationprinciple treatedin some detail, as the preparation of the raw materials, thestorageand homogenizationof therawmeal, andthecoolingof thecementclinker.This latest edition of the Handbook moreover contains up-to-date information firingtechnology, kilnsystemsandrefractoryliningconstruction.Clinker storage now has separate section allotted to it. / view of today's withenvironmental pollution prevention, the dust-free storage of large quantitiesofclinker isveryimportant.Present-day methods of packing and despatch loading described (Chap-ter ) .Whereas the subject of materials handling and conveying(ChapterF)was rathersummarily dealt withinearlier editions, it has nowreceivedmuchmore detailedtreatment. Feedingandproportioning alsoincluded.Process engineeringandautomation of suchimportanceinmoderncementmanufacturing technology that theyhave separate chapter devoted to them, inwhichtheprincipal aspects consideredinsome detail (ChapterG).Thesubjectsof environmental protectionandindustrial safety (Chapter ) now likewise fully dealt with in the Handbook for the first time. These subjectsof great importance in connection with modern cement manufacture, whichindeed carriedout onlyif the statutory and other requirementsrelatingtothem duly compliedwith.The book contains some further chapters devoted to various matters that thecement worksengineer: maintenanceandwear; workshopsandsparepartsstore; water supply, compressed air; personnel requirements; lubricants; firefight-ingequipment; laboratoryequipment.21 Rawmaterialsandquarryingmethods.2 Exploration . . . . . . . . .2.1 Explorationprocedure . . . .2.1.1 Trial pitsandsurfacesamples .2.1.2 Drilling .2.1.2.1 drillinginlimestone.2.1.2.2 barrels2.1.2.3 Flushingmedia . . . .2.1.2.4 drillinginclay ..2.1.2.5 Treatment ofthecores.2.1.2.6 Testingof drilledcores.2.1.2.7 Rotarypercussivedrillingwithcrawler-mountedmachines.2.1.3 Stratigraphicinvestigations.2.1.4 Tectonics .....2.1.4.1 Limestone deposits ...2.1.4.2 / component. . . . .2.1.4.3 Overburdeninvestigations2.1.5 Geophysical investigations2.1.6 Hydrogeological investigations2.2 Laboratoryinvestigations. . .2.2.1 Chemical investigations ...2.2.2 Mineralogica/andpetrographicinvestigations2.2.2.1 Limestone.......2.2.2.2 Claycomponent. . . . . . . . . . . . . .2.2.3 Physical investigations. . . . . . . . . . .2.3 Evaluationof theresu Its oftheinvestigations.2.3.1 Geochemical evaluationwithquarryingoperationsplanning.2.3.2 Calculationandclassificationofreserves. .2.4 Organizing explorationproject. . . . .2.5 Using computerin explorationproject.References. . . . . . . . . . . . . . . . . . . .46678991112121314141515161617202020212122222223232425253Rawmaterials 1. Geology,depositsQuarryingmethods1 Raw materials and quarryingmethods 1 : Nomenclature of clay. silt. etc. in accordance with particle sizedistribution(DIN 18123)Therawmaterialsfor cementwhich thesubject of geologicalexploration mainly limestonesandclays. thegeological senseboth sedimentary rocks which may occur as hard dense material (commonly knownas "rock") softer soil deposits. They may of geological age. Limestonesmostly intheformof rock, sometimesconstitutingwholemountainousformations. Europe, moreparticularlytheDevoniangranular limestones, theJurassic and Triassic limestones oftheAlpine region and the Cretaceous limestonedeposits ofimportance.Whereas the limestone deposits of the Precretaceous period usually composedof fossil limestoneswhich inmany instancesweresubjectedtometamorphicchange (e.g., marbIes, siliceous limestones), the younger and mostlyPostcretaceouslimestonesoccur bothasfossil depositsandaslimestone-clay The latter referred to as lime marl (calcareous marl) marl,depending the limestone/clay ratio of the mixture (see Duda, Vol. 1, Section 1).These limestones also include the so-called cements in which Si02,

and

present in suchproportions that the lime standardis around1OOand the desired moduli obtained bythe addition ofonly small quantitiesof correctivematerials. Suchdeposits however, The youngest recent andsub-recent limestonesinclude coral limestones, whichoccupy in some cases intermediate position (consolidated) rock andunconsolidated material. Deposits of shells, which also used in the of cement clinker, belongtothelast-mentionedcategory.The clay mineral component used for cement manufacture will generally soft material: clays, silts, sands with high content of clay minerals.Thesematerials classifiedaccordingtoparticlesizedistributionrather thanmineralogical composition 1).Rock-type clay materials may occur as clayslate, shale and(to some extent)crystalline slates. Subject to chemical suitability,such rocks as granites, gneisses, basalts and basaltic tufas pozzolanas may alsoserveas claymineral components.Additive materials for ciinker production may needed for correcting thechemical composition of the raw mix, e.g., materials providingFe, Si02

moreparticularlythemost inexpensiveonesthat servethe e.g.,roasted pyrites low-grade iron laterite, quartz sand quartziferousweatheringproducts of metamorphicrocks, andbauxite.claysiltsandgravelstones463mm 2: limits imposed the MgOcontent of portland cementmaterials Standards in various countrjes (according to Cembureau.1968)Country max. % MgO weightRumania 2.5Belgium, Denmark 3Italy, Mexico, NewZealand, Pakistan, Portugal,Great Britain 4Australia 4.2Bulgaria 4.5Argentina, Austria, Canada, Chile, Cuba, Finland, France,GermanDemocratic Fed. ofGermany, Greece,Hungary, Indonesia, Ireland. Israel, Japan, Netherlands,Norway, Poland, SouthAfrica. Spain, Sweden,Switzerland,Taiwan, USSR, Venezuela,Jugoslavia, People's ofChina 5Brazil, Czechoslovakia. India, USA 6Theassessment of the suitability of therawmaterials forcementisbasedchiefly their chemical composition. Forlimestone components the so-called lime standard is used as criterion, giving information the content aswell as the"hydraulic"constituents Si02,

and

It isin casepreferabIe toassessingthematerials merely thebasis of content.The rocks to used as clay mineral components most suitabIy assessed calculationofthe silicaratioandthealuminaratio.For deciding the suitability of raw materials it is furthermore essential to performmix proportioning calculations in order to ascertain the content of alkalies,sulphates, chloridesandMgOintroducedinto therawmix.ThepermissibIelimit valuesforthecontentofsulphates, alkaliesandchloridesmust conformedto.The content of magnesiumthat permitted is laid down in standardswhich vary from country to another 2).ltwill haveto decided in eachparticular case whether anything in excess ofthe standard specified content allowed, since there suitabIe raw materials that fulfilthe requirement of,inmost cases,not exceeding about 4-5% MgO weight) in the cement. Undercertaincircumstances, too, economicreasonsmay constitutedecidingfactorinjustifying departure fromthestandardlimit.Explorationof limestoneandclaydepositsfor cement clinker manufacturehasthreeaims:(1) verifyingthequality of therawmaterials;5Rawmaterials 1. Geology,deposits(2) estabIishing the range of variationin quality of the rawmaterials throughouttheworkinglife of thedeposit;(3) verifyingtheworkabIereservesof rawmaterials.For the technological planning of the machinery for cement manufacturing plantit isof major importancetoascertaintherangesof variationof individual rawmaterial constituents in the deposit throughout the operating life of the plant, foronly in this way operation yielding final product of good quality ensured. Variationsof relativelyshort duration, rangingfrommonthsuptoabout half should also known in good time, so that suitabIe precautionsin terms of machinery andprocesstechnology taken otherwise, intheligbt of economic considerations,correctiveingredients that will help maintainproduct ofunvaryingquality quarried purchased.Explorationforlimestone andclaymineral componentsfor cement manufacturemainly comprisesgeochemical investigations, thoughthe bedding conditions ofthedeposit alsoplay important part withregardtosubsequent planningofthequarryingoperationstomeet therawmaterial requirementsof thecementworks.Besidesqualitativeconditions, thedeposit will alsohavetofulfil quantitativeconditions more particularly in connection with the method of quarrying digging to employed.Cement works withclinker outputs of between1000 and 6000t/dayneed rawmaterialinput of 2000 to 12000t/day(assuming clinker production 330 daysandquarryingoperations 260-280days about 50-90%of thisquantitybeinglimestoneand 10- 50% claymineral material.2 Exploration2.1 ExplorationprocedureThe exploration procedure will always have to suited to the particularconditions of the deposit under investigation, so that it is here not possibIe to givemore than general outline description.Generally speaking, the exploration of cement-grade deposits will comprise threestages:Stage 1: Field inspection of number of deposits, surface tests, limited number ofexploratory borings (including core borings, if necessary), simple hydrological andtectonicinvestigations, large-areamapping.Theobject of this first stageof exploration, which referred to asreconnaissanceprospecting,is to select or more deposits for further detailedprospecting. In this connection the quality of the deposit is especiallyimportant,whileprobIems of mining or quarrying aregivencomparativelylittle attentionatthisstage.Stage2: completionof thefirststage, ormoredepositsare selectedfordetailed investigation. the basis of comprehensivedrilling programthe6Explorationprocedure: Trial pitsandsurfacesamplesdeposits broadly studied with view to ascertaining their chemical characteris-tics over extensive areas. In conjunction with the borings, further investigations arecarried out for determining the bedding conditions, ground water and possibilitiesof workingthedeposit, theobject beingtoassessthesuitabilityof siteforquarrying or open-cast working. More particularly, the second stage aims to findthe most suitabIe area for siting the quarry or to select the most favourabIe of two ormoredepositspotentiallyavailabIeforsupplyingtherawmaterials.Stage 3: Thisis the stage of detailedexploration, using gridof closelyspacedboreholes for the purpose of determining chemical properties of the rawmaterialcomponents and their variations over short distances, in order to gear the processengineeringdesignof thecementworkstotheseconditions.Furthermore, special investigations for planningthe quarrying operations carried out. Thestructureof thedeposit is studied in detail. Inaddition, thepossibility of working the material ripping may, for example, examined. Whiletheseexploratoryoperations inprogress, assessment of theresultsalreadyavailabIe is undertaken, so that probIems emerging therefrom fed backto the exploration work andduly takeninto consideration. completion of thethird stage of exploration, the deposits are fully known as regards their qualitative,quantitative and mining or quarrying engineering features and got ready foropening-up.2.1.1 Trial pits andsurface samplesTaking samples from trialpit is usually form of surface testing, because it is notpossibIe economically todigshafts of great depthintolimestonerock. theother hand, withclaysoilsit is possibIetobasetheexploration comprehensivegridoftestshafts. However, iftheclaydeposit is of substantialthickness, it is better to use drilling techniques, as the digging of deep shafts is veryexpensive.Mostly combinationof the twomethodsisadopted.Withlimestone, pits duginplaceswherethesolidrockiscovered othermaterial which has to removed in order to expose the limestone for testing. Suchexploration alsoaffords opportunity of testing theoverlying material andassessingitspossibIeusefulness.When the surface of the rock has exposed excavation, or if it occurs as outcrop, material for examination sampledintwoways: either asspotsamples from locally limited of exploration or as continuous samples takenalong line (or long exploration trench) extending at right angles to the strike.Withcontinuoussamplingit isimportant that thesamplesshould properlyrepresentativeof therockstrata under investigation. This most simply achieved excavating cut fromwhich, for approximatelyunvaryingcross-section, constantquantity of samplematerial perunitlengthis obtained.If cut is too expensive or indeed impracticabIe, it will alternatively necessary totakefromthestratainquestion samplequantitywhichbears appropriaterelationtotheirdepthandextent.7Rawmaterials 1. Geology, depositsWhen trial excavationis made, sampling andtestingshould,as faraspossibIe,not confined just to the surface of the limestone, but should extend down to atleast below the top weathered layer of rock. most cases this will require the aid of heavy excavator rockbreakinghammersand compressor. youngchalklimestones corallimestones ripper evenlighter equipment suffice forthepurpose. caseitmust investigatedwhetherthelimestoneisliabIetoundergochanges in its chemical character as result of atmospheric influences, weathering,circulating underground water, ground water occurring close to the surface. Inthelast-mentionedcase thechemical properties of theground water also ofconsiderabIeimportance.If clay occurs in the formof loose-textured soil-type deposit, exploratoryexcavations(trial pits,etc.) made withsimple means.The stability of thewalls of such excavations should given due attentionin view of the danger to working in the excavation, to machines stand ing at the edge thereof, arisingfrom sudden collapse of wall. If necessary, timbering will have to installed.The arrangement of trial pits andtrenchesin clayis similar inprinciple to thatinlimestone.The sameis true of thesamplingprocedures.It isadvantageoustohavehermeticallyclosabIejars canistersavailabIeforstorage of the rock soil samples with their in situ moisture contentbecause particularlywithclaysthemoistureconditions importantdecidingwhat typeof preparatoryprocessingmachineswill haveto used.Where excavating machinery is used for digging the trial pits, the experience thusgained provideuseful indicationswithregardtothep/anningofthefuturequarryingoperations(Iumpiness, stickness, distintegration, suitabilityfor vation means ofpower shovels, wheel loaders, etc.).2.1.2 DrillingThe selection of the most suitabIe drilling boringmethodin terms of technicalsuitability and also of is the fundamental condition for successfulexploration. themain, there threedrilling techniques tochoosefrom: drillingofcuttings circulating water other flushing wlthcontlnuous extraction; percussive rotary drillingwlthremoval of cuttlngs means of compressedair. drilling with rotary bits and removal of cuttings with the flushing mediumIS sUltabIe only in exceptional cases for exploratory drilling in solid rock deposits. Ifthismethodisused, itshould knowninadvancewhether itwill not causechanges in the chemical character of the samples, g., the dissolving of solubIecompounds(alkalichlorides,for example) failing toreveal the presence ofmarl strata clay enclosedwithintherockunderinvestigation.Similar considerations applicabIetopercussiverotarydrillingwithcrawler-mountedmachines of the typeusedforthe drilling of bIastholes. This methodisunsuitabIe fordeposits consistingofloose-textured soil-type deposits. drillingis the most reliabIemethod of obtaining samples for assessment.this technique continuous is extracted over the full depth of the hole, so that,8Explorationprocedure: Drillingifthedrillingoperations carriedout suitabIyexperiencedpersonnel, thegeologist obtainfull information of all details of thelimestone deposit at alllevelsbelowthesurface.2.1.2.1 drillinginlimestoneFor successful exploration withtheaid of drilling thecorrect choice of drillbits, barrelsandf/ushingmediaisof majorimportance.For borings inlimestone thediameter should not less than75 Withsmaller diametersthereis riskthat jammedcoreswill pulverizethinsoftintermediate strata, that the hole will choked cavingandthat material fromsome strata removedalongwiththeflushingmedium. limit tothe diameter isimposed considerationsof Diameters of 120 and upwards seldomused, except under criticalconditions where drillinghas to done withwater flushinporous rock and, employing large diameter, washing-out of solubIe compounds preventedat least in the interior ofthe the other hand, cores which too small willmake the evaluating geologist's task awkward, while the halves into whichthe specimens split for the purpose of possibIe supplementary follow- tests thenratherunsuitabIe forthepurpose.Thechoiceof suitabIedrill bit will depend therock itself: thebedding,fissuringandtectoniccharacteristics of thedeposit, andtheabrasiveness of therock. Carbide-tippedas well as diamonddrill bits used.Withlarge diametersandheavily fissuredrock the risk that parts of the will tilt and jamin the barrel is greaterwith carbide bits; besides, the is exposed to the action ofthe flushing medium than with diamond bits. such cases the choice of the mostsuitabIebit will depend theforeman-driller'sexperience.2.1.2.2 barrelsThreetypes of barrel availabIefromwhichtomake choice:the single tube, the doubIe tube and the wire line type. addition, there specialtypes of barrel, which have to used under exceptionally difficultconditions.Thethreetypes illustratedschematicallyinFig. 1. Thesingletube isprovided, itsbottomend just abovethe bit, with catcherring whichgrips thedrilled duringextractionof thedrill rodandthuspreventsit fromdropping down the hole. The basic condition for successfully using the single tube is that the rock is of such kind(massive and uniformly strong)that indeed drilled from it. If the limestone is composed ofthin plate-like strata if it easily disintegrates during drilling, there will risk that part of the willfall back into the hole extraction. Furthermore, in such cases the geological andgeochemical assessment andanalysis of thesampleisrather difficult,sincethesample consists merely of fragments which make it impossibIe to out all thenecessaryin detail. Another and very serious drawback of the singletubeisthatthe isenvelopedin flowofflushingmediumalongits entire9Rawmaterials 1. Geology, depositsExplorationprocedure: DrillingFig.1: Types ofcore single tube barrel (1), doubIetube barrel (2),grappledevice(3) withwirelinebarrel (4) (based informationfromAtlas Special doubIe tube barrels equipped with bits which so designed thattheflushingmediumdoesnotemergefromthegapbetweentheinnerandtheouter tube, but is discharged to the outside before within the cutting edge of thebit. Insidethebit (Fig. 1) theinner tubeisinsuchclosecontact withit, thatpractically water get tothe sample.If borings carried out in very soft and shattered material (though firm enough to stabIe hole to drilled), it is possibIe to use specialdoubIe tube barrel in which third tube, made of plastic, inserted into the inner tube. The isthenremovedtogether withtheplastictubefromthebarrel, sothat substantia/lyundisturbedsampleforassessment is obtained.If the deposit consists of material in which it is not possibIe drill stabIe hole evenwithmudflush, wirelinebarrel used.With thewire line barrel thewhole drill rod isofthe same diameter as the barrelitself. The inner tube, however, is not permanently connected to the outer tube ball bearings, but is gripped in it means of catcht.he of corresponding to the length of the barrel has drllled, wlre wlthkind of grapple is loweredinto the hole and releases the catch, enabIing the tubecontaining the sample to drawnup. This procedure offers the advantagethat the drill rod need not extracted in order to extract the sample from the hole,sothat theriskof cavingand bIockageof the holeisobviated. Besides, theoperationof extracting the tubetakesless timethanit does withtheothersystems. There also special wire line barrels in which the flushing mediumemergesbeforethecuttingedgeof thebit, sothat thereishardly contactbetweenthe andthemedium.2.1.2.3 FlushingmediaThe choice of the flushing medium for borings in limestone is of major importanceinconnection withthe subsequent geochemical investigation of thesamples.It has already noted that with fluid medium for flushing the borehole there is risk that clay andmarl strata, as wellas sandand silt inclusions, will washedout and that solubIe constituents of the limestone willlikewise lost. principle, distinctionis to drawn between air andliquid flushing media. all cases airflush ispreferabIe, becauseit ensuresthat constituentswill removed washing dissolving action. With air flushit is often unnecessary to use doubIetube barrel, for in the single tube the samle is enveloped only in stream of air,thoughadmittedlytherateof drill bit wear is thenhigher.With water flush the pressure of the water should kept as low as possibIe. Thehigher the pressure, the greater is the risk of disturbing the sample washing outsome of the material. For the purpose under consideration water is the only suitabIeliquidflushingmedium otherwiseonlysuchmediawhoseconstituents afterwards, in the chemical analysis of the rock samples, unambiguously identifiedashavingoriginatedfromtheflushingmedium.In connection with water flush, the porosity of the limestone is of majorimportance. In case the water used for the purpose should analysed to makeAuBenrohrouler lube U SpUlflUssigkeitflushing medium(f(uid)2 Iflushingmedium (fluid)Kernrohr ifIIlength, so that, especially if water flushis employed, fine stone chippings and sandy, silty clayeyinclusions likelyto washedout.With the doubIe tube type of barrel the inner tubeis connected throughballbearings to theouter tubeandthereforedoes not revolvewiththelatter (whichcarriesthedrill bit). Inthiswaythe remainsatrest andthussubstantially The most important advantage of thedoubIe tube, however,is thatthe is not enveloped in the flushing medium, which is, instead, forced throughtheannular spacebetweentheinner andtheouter tube. The comesintocontact withthe flushingmediumonly at thelower endof thebarrel,where theinner tube terminates and gap for the passage of the medium exists between thetwo tubes.Because of this limited of contact, very little of the is washedout, though of course some dissolving of solubIe constituents in this cannot avoided.1011Rawmaterials 1. Geology,depositsit possibIe subsequently to draw conclusions as to effect that it may have had the samples. For example, if salt water is employed, it will in case difficultto distinguish between the alkali content of the limestone and the alkali introducedwiththeflushingwater.Inhighlyporouslimestone which suspectedof having highcontent ofalkali, chlorineandsulphate the drilling technique withair flushis the onlypossibllity of obtainingsuitabIe samplesforgeochemical investigation.2.1.2.4 drillinginclayIfthe clay mineral componentfor cement manufacture occurs in the form of solidrock (shale, slate, etc.), thesamedrillingtechniquesasfor limestone applied.However, if it occurs as non-cohesive soil, other methods will have to chosen. such cases, as rule, percussive drilling will used and the hole will casedas drillingproceeds, soas toprevent caving extraction of therod.Thesar:npling device usedin borings of this type is usually spoon sampler which, extracted, closes its lower end and thus prevents the soil sample from fallingout. The sample obtained in this way is however, so that the informationit gives beddingconditions, etc. may questionabIe.This technique also applied tocohesive soils, but in such soils it isalternativelypossibIe touse rotarydrill,equippedwith carblde-tippedblt. If samples required, barrel ofthedoubIetubetype used. manyinstances, however, single tube barrel will adequately servethe if water flush dispensed with. Drilling operations liabIe to particularly difficult, even if little water is used, in clays containing minerals whict1swell and thus cause narrowing of the hole.Under such conditions it is certainlynecessarytocasethehole directlyabovethedrill blt.Drilling in friabIe material should, if at all possibIe, performedwithout flushingmedium. especially difficult cases the drilling operations may carried out with doubIetube barrels wire linebarrels equipped with plastic inner tube forenclosingthesample. Theplastictubeiswithdrawnalongwiththesampledmaterial andserves alsoasitscontainer fordespatchtothelaboratory.2.1.2.5 Treatment of thecoresThecoresextractedfromtheboreholes stored inboxes. If they to transported freight overlong distances, theboxes should made of suitabIystrong materlal and strengthened with metal. Cores obtained fromloose-textureddepositsshouldadditionally protectedinplasticbags.1nthefield, thecoresshould recorded thegeologist directly theirremoval from the barrel. Such records most suitabIy supplemented photographs of each Fieldsrecords should as comprehensiveaspos.sibIe so as to the samples also to correlated with supplementaryborlngsthat may madelater withtheactual conditionsencountered 12Explorationprocedure: Drillingopening-up the quarry. The drilling report should contain technical data relating tothedrillingoperationsandalsogeological data, sothat, whenthegeochemicaltests resultsbecome availabIe, complete diagram for eachborehole is obtained.Eachreport shouldcontaininformation thelocation, altitude of thestartingpoint and designation of the borehole.For each drilling depth, the diameter of thehole, the type of barrel, the type of blt and change of blt, amount of covered, flushing losses and rate of drilling progress should noted. With the aidof this information it will, in the event of subsequent additional investigations, possibIetodiscusswhetherdrilling donemoreeasilyandcheaplywithdifferent equipment. the foreman-driller should keep record of theease difficulty withwhichthe rock drilled. Althoughthisis matter ofsubjective judgment, it facilitate the work of correlating the profiles in rock ofmacroscopically veryuniform character.The correct geological description of the samples comprises the designation of thetypeof rockpenetrated, the of therock, itsgranularity, information inclusions of foreignrock mineral inclusions, porosity andhardness,bedding, andinformation faultsencountered.eachdrillingreport shouldrecordthesamplestakenfromthe drillingrun,unless the is dividedand half is retained for possibIe reference. Ifinformation approximatestratigraphicclassificationisavailabIe,this too should includedin the report. Under certain circumstances, field testsmay performed thecores in order tocheckthe content thesuspected presence of MgO. The results of these tests likewise to added tothe report. graphic representationof the conditions encounteredis in casenecessary.2.1.2.6 Testingof drilledcoresForthe of testing, thecores dividedintosections thebasisofmacroscopiccriteria. Eachsectionisthensubdividedintoportionsforanalysis,withdueregardtothemethodof quarryingto employed. Inthecaseof relativelythindeposit, i.e., of limiteddepth, whichwill haveto worked ripping if ripping has to applied for other reasons), the length of the analysisportionsshouldnot exceedtwicetherippingdepth. theother hand, if benching isto employed, theportionsfor completeanalysis shouldnot more than5 mlong.If at possibIe, the should dividedin halves, half being retained forreference, whiletheother issent tothelaboratory. Coresof very largediametermayalso quartered.If such division of the is not possibIe, the whole must despatched tothe laboratory, where it may have to comminuted crushing. such cases the portions shouldnot exceed1 m inlength, in order to keep down the cost ofanalysis(seebelow).13Rawmaterials /. Geology,deposits2.1.2.7 Rotarypercussivedrillingwithcrawler-mountedmachines supplement the borings and to fill in the network of boreholes in solid rockdeposits, additional drilling carriedout inexpensivelywiththeaidof drillingmachine,of the typeused alsofor the drillingof large-dlameterholes forbIasting.The. drill bit, operating rotary percussiveaction, shatterstherock, andthecuttlngs removedfromthehole airissuingfromthebit.Thedustcarriedoutof theholewiththisflushingair trappedin dustcoll.ector, whichismounted thedrillingmachine. It comprises cycloneinwhJch thecoarser particles precipitated, whilethefiner ones retainedinspecial filters. Thesuction extractor isconnectedto flexibIetubewhichterminatesin plasticsleeveforming airtight closureoverthemouthof the?orehole, sothat all thedust collected. For testing thesamples it is not onlytoanalysethedust precipitatedinthecyclone, but alsotoInclude thefineparticlestrappedinthe filter equipment.With borings of this type it often occurs that the dust is collected without the aid of suction extractor, merely p/acing sheet of plastic around the top of the holeand collecting the dust, discharged from the hole, this sheet. This methodis to u.nl.ess the object of such borings is merely to obtain approximategUldlng If It IS desired, quickly to obtain details of the chemical compositionat partlcular point in deposit which reliabIe information isalreadyavailabIe.Clay intercalations, sandinclusions soft moist limestone strata forced aside the rotary percussive drill bit and remain sticking to the wall of the borehole, so sampleofsuchmaterial isnotobtained. Norisit possibIetoget the presence of cavities in the rock. The most serious drawbackof rotary percussive dri/ling, however, is that it offers possibility of sampling therock as such and thus forming reliabIe picture of the occurrence of limestone inthedepositunderinvestigation.2.1.3 Stratigraphicinvestigations prospectingfor rawmaterialsfor themanufacture ofcement onlysecondaryattaches to stratigraphicinvestigations, because the suitability of therawmaterlalsdependsmainly chemical featuresandisnotconfinedto particulargeological age. stratigraphic investigations usually limited to macroscopic of the drilled cores and to assigning characteristic datum horizons forcorrelatingtheindividual borings. important, the otherhand,is the chemostratigraphic examination of theborehole profiles, especially if thedeposit appearsto of very unvaryingcharacter theevidence of fieldobservationsandof thecores.Quite oftenit is only in this way that differences in facies ascertainabIe whichwouldotherwiseremain undetected. Suchdifferences nevertheless ofconsiderabIe importance in connection with the subsequent planningof the14Explorationprocedure: Tectonicsquarryingoperations, e.g., iftheaverage contentof thelimestoneisonlyabout 46% andthereis markedshift tolimemarl facies.2.1.4 TectonicsOf greater importance than stratigraphicinvestigations in the present context investigations the bedding conditions and structure of the deposit. The preciseinterpretationofthesefactorsconstitutesthebasisforthereliabIegeochemicalevaluation of the results of the borings and for planning the quarryingprocedure.2.1 .4.1 Limestone depositsThe investigation begins with surveying the availabIe exploration points relating tothe deposit. The bedding features and faults affecting them observedand measured there.Particular attention should paid to "micro-tectonics", i.e.,the structural characteristics and their variations within distances of the order of fewmetres indeedof decimetres, sincesuchcharacteristics of majorimportanceindeterminingthealignment of thequarryface. Furthermore, theexploration points provide information the presence of strain zones whichmanifest themselves in variations inbed depth whichhave causedfoliation ofthelimestone.Fracturingandfaultswhichextendas lessstraight planesthroughthelimestone important inconnectionwithfurther planning. Younglimestonedeposits, in particular, often penetrated such fractures whose faces oftencrusted with calcite and coated with thin of clay. Such planes should receiveparticular attention in quarry p/anning, because ground vibrations due to bIasting liabIe tocause subsequent rock slips along these p/anes, resultingin suddencollapseoflargeportions of thequarry face.If theexploration pointsavailabIefor thedeposit not sufficient topermitcompletemappingof itsstructural features, photogeological mapping helpful, provided that aerial photographs in thescale range from1: 5000to1 : 15 000 obtainabIeandthevegetation theterraindoes indeedallowphotogeological interpretation.Another valuabIeaid in assessingthestructural conditions of the deposit isprovided the results of borings. For these, correlation based primarily the stratigraphic description of theindividual borings.Suchcorrelation must notwaittill thedrillingoperationshave completed, but shouldproceedat thesametimeas thoseoperations, inorder tomonitor and, ifnecessary,correct thelocations chosen for the further exploratory boreholes in the light of the structuralassessments.Interpretationofthemacroscopicstratigraphic drillingrecordsislinkedto sections along the network of boreholes and to maps indicating the depthsat whichparticularstratigraphichorizonsoccur. thisway goodideaofthestructure of deposit obtained, which supplemented with the resultsof geochemica/ investigations.15 . Rawmaterials 1. Geology,depositsThe chemical data of eachborehole,like the stratigraphic details, are recordedinprofiles andsub-surface contourmaps,sothat then, combinationof the twosets of evaluated data, the tectonic and the geochemical structure of the deposit isclearlyapparent.The tectonic data are especially important in case where, as result of secondaryactions, changesinthechemical propertiesof thelimestonehaveoccurred either side of fault. Although such variations are of locally limited character, theyareliabIe to cause entirely different rawmeal conditions for time duringquarryoperationandmaterial processing.2.1.4.2 ClaycomponentIf theclay component occurs as solid rock-type material, therequirementsapplicabIetothe tectonicinvestigations arethesameasthose for limestone.' deposits consisting of softer material thorough tectonic investigationis moreparticularlynecessaryifadjacent or underlyingstratashow distinct deviationfrom thechemical character of the clay mineralcomponent. Furthermore, water-bearing horizons affected faults encountered during excavation. Also,the stability of slopes is often affected tectonic conditions, which give riseto difficulties in excavating the material, especially in countries with heavyrainfall.2.1.4.3 OverburdeninvestigationsThe layer of material which overlies the deposit should included in theinvestigation, in order to decide whether such material is to discarded as uselessoverburden or utilizedin theproductionprocess, e.g., aspart of theclaymineral component oras sandadmixture.The overburden investigated with shallow borings, soundings (penetrationtesting) ortrial trenches.Samplingisdone the samemethodsasthose for looserockorsoil.If theoverburdenissolidrockor similar consolidatedmaterial, it isespeciallyimportant to assess its potential usefulness, for otherwise its removal as mere wasteisboundto cost-intensiveoperation(e.g., bIasting).If the object is only to investigate the depthof overburden, geophysical methods advantageously applied. ' casewhere theoverburdenis of loose orfairlysoft character, seismicmeasurements, moreparticularly meansof thehammer bIow technique,are very suitabIe,as they performed quickly andinexpensively. However, this technique does require relatively level surface ofthelimestone. If thesurfaceisveryirregular,e.g., as result of undergroundwaterpercolation,thismethod of investigationcannot used. Theapplication of thehammer bIow technique inconjunction withpenetrationtestsis especially to recommended.With greater overburden thicknesses it is alternatively possibIe to use geo-electricmethod (based contrasts in the electrical resistivity of strata), which veryeffectivemoreparticularlywhen used in combinationwiththehammer bIowtechnique.16Explorationprocedure: Geophysical investigationsFor interpreting and evaluating the overburden investigations it is most suitabIe touse which lines of equal overburden depth have drawn, unless thedepthisuniformandverysmall.2.1.5 Geophysical investigationsHammer bIow and geo-electric methods represent two simple geophysicaltechniques which used with relatively little effort and expense fordetermining the depthof overburden,the thickness of consolidatedanduncon-solidated strata, the detection of waterbearing strata, and ascertaining the groundwater tabIe. ' addition, determination of the velocity of sound transmission in thegroundprovidesindicationsastowhether thematerial brokenout ripping.The hammer bIowmethod isespeciallysuitabIe incaseswherethedepthofexploration is limited to 10-15 . The seismic shock (setting up vibration in theground) isproduced with heavyhammer whichautomatically switches theelectronic measuring equipment. seismic detector(geophone) responds to theground movements and displays them oscillograph. The time it takes for thefirst shock wave to travel from the hammer to the detector is measured(Fig. 2). Ifthe distance from the hammer to the detector is large enough, the wave produced thehammer will refractedat the stratumboundary penetratinginto theunderlying material, moreparticularlythe bedrock. Thedistancebetweenthehammer and the detector is progressively increased, and in each position the wavepropagationtimeismeasured.'L::==_..5578 ,Fig. 2: Propagation and refraction of seismic waves, and time-distancediagram17Rawmaterials 1. Geology,depositsExplorationprocedure: Geophysical investigationsThe results to begin with, represented graphically, the propagation time beingplotted against the hammer-to-detector distance. The points inthegraph connected to another straight lines which show changes in slope accordingtothe number of strata involved. Thereciprocalsof theslopesof these linescorrespond to the wave velocities in the respective strata. The velocities mostquickly calculatedfrom thelinear regression of the measured values,omittingthe values close to the"breaks"(changesin direction) because those values unreliabIe account of transitioneffects: = + where = timeaxis(t) = distanceaxis(s) Seismic velocitiesresidual (weathered) soilsand, gravel,drysand, gravel,wetclayshalelimestonesandstone300- 600 m/s450- 900m/s600-1500 m/s750-1500 m/s1200- 2000 m/s1600-3000 m/s1600-4000 m/sWhen the lines have calculated, their intersections determined and thedistances from these "breaks" the graph to the origin(point then workedout. With this distance and the velocities in the two stratait is possibIe to find thedepthat whichtheinterface boundary surface of thestrataislocated:Another geophysical method, somewhat elaborate as regards its applicationandinterpretation, isthat ofgeo-electricexploration, whichhas substantiallygreaterrangeindepth(toabout distinctionisdrawnbetweengeo-electric mapping, comprising substantial areas of the subsoil, and soundingswhichgivein-depthinformationat specificexplorationpoints.Inbothcasestheso-calledfour-point arrangement isusuallyadopted(Fig.3),comprising outer pair of electrodes to which voltage is applied and innerpair ofelectrodesS(probes) across whichtheresultingvoltageismeasured.In thesoundingtechnique,the distancebetweentheelectrodesisprogressivelyincreased, so that changes in the electric potential distribution in the ground occurand measured,thusenabIingtheapparentresistanceto calculated.The potential distributionin the ground depends substantially the thickness ofthestratawithequal electrical resistivity.If strata differing in their resistivity present, the pattern of potential distributionat thesurfaceof thegroundisaltered. Theinterpretationof theresultsof thev= velocityinthestratum.1v, ---2 V2 + v,whereD= depthof interface= distancefrom"break"topoint Vn= velocityinstratum Sincethismethodof seismicexplorationoperateswithonly limitedinput ofenergyfor producingthegroundvibrations, it usedonlyfor depthsnotexceeding about 10-15m and comprising not than three strata.For greaterdepths it will necessary to use explosive charges for producing the vibrations.The advantage of the hammer bIow methodis that the equipment with the cabIesand accessories weighs only about 25 kg and that, operated two it iseasilypossibIetomeasure10-15profiles day. Quiteoftenthismethod suitabIy used for the mapping of sand marl horizons the ground water tabIeinclaydeposits. important requirement is that the velocities in the respective strata 3) sufficientlyfar apart, i.e., differinginmagnitude, to themto reliabIydistinguishedfrom another.Fig. Current paths and potential distribution in geo-electricmeasurements = electrodes. S= probes)1819Rawmaterials 1. Geology, depositsmeasurements with progressively increasing electrode distances enabIes theresistivityandthickness oftheindividual stratato determined.If geo-electric mappingis required, the electrode spacings kept constant andthe whole set-up is moved along to different locations. this way showinglinesof equal resistivity isobtained, e.g., enabIing largesand inclusions, thesurface of water-bearing stratum the undersurface of raw material deposit to mapped.2.1.6 Hydrogeological investigationsForplanningthe quarryingoperationsitisnecessary toknowthegroundwaterlevel thesiteto worked. Themost convenient methodof obtainingthisinformation is observing the water level in the boreholes. If the water flushtechnique is used, it is necessary to wait some time until the water introduced intotheholeduringdrillinghasdispersed. In case, thewater level observationsshould continuedover full soas toinclude seasonal variations.Hydrogeological observations liabIe to particularly elaborateinlimestonedeposits with karst characteristics, where comprehensive network of water levelobservation points will needed. If the boreholes fail to provide adequateinformation groundwater level, geo-electricsoundings employed,which moreover supplemented geo-electricmappingof thegroundwater tabIe.Explorationprocedure: LaboratoryinvestigationsMgOin thelimestone, 5i02,

and

in the clay mineralcomponent.testing the limestone the amount of residue insolubIe in shouId always also stated, becausethisresidue containminerals whichsignificantlyaffect theMgOcontent.After the resultsfor the1 mportions have determined, mixtures of theavailabIe samples prepared, thus providing composite samples comprisingseveralmetres of borehole depth. Complete analyses performed these. Forthis purpose it to begin with, suffice to perform only limited number of suchanalyses for overall guidance,. If these show the alkali content to substantiallyuniform, thealkali analyses reduced in number soastocompriseeven larger samplequantities, i.e., representativeof material from greater lengthof borehole. In case the compounds 5i02,

andMgOshould determinedonlyforsamplesectionsofsuchsizethatit ispossibIetoalter thequarryoperationsplanningaccordingtothegeochemicalrequirements. For example, if bench height of 15 m is intended, it is, with sectionsof 5possibIe to shift the level of bench upwards downwards, in order thus tokeep the quarrying geared to, as far as possibIe, equal geochemical conditions. fluorescenceanalysishasprovedveryuseful foranalysingrelativelylargequantities of limestone and clay samples in short time. The alkali and the sulphatecontent will have to checked wet chemical analysis,however,because theresultsof fluorescenceanalysistendto unreliabIeexcept whensuchanalysis is performed very experienced personnel. Wet analysis willin case neededfor determiningthechloridecontent. connection with the exploration of limestone for cement manufacture,mineralogical andpetrographicinvestigationshave lessimportantpart toplaythanchemical investigations.Quite often the limestone occurs in natural mixture with clay, andin such casesthe designation based thechemical analysis,using thenomenclaturegiven KLihl (1958) (cf. Vol.ll, Chapter 2of his book "Zement-Chemie"). ineralogical investigations of interest if the aim is to separate the raw materialinto lime-rich and clay-mineral-rich components respectivelyg., for themanufactureof whitecementclinker, involvingtheremoval oftheconstituentscontaining

5uchinvestigationsassumegreater importanceindealingwithsiliceouslime-stones. For such materials it is necessary to ascertain the distribution of the quartzin the limestone matrix. The type of intergrowth and the grain size of theconstituents determinedinthinsectionsunder themicroscope.TheresidueinsolubIein shouldalso examined. This most simply done dissolvingawaythecalcareousmatter withmonochloroaceticacid formicacid, followed examination of theresidual material.Furthermore, the distribution of dolomite investigated means of staining2.2 Laboratoryinvestigations2.2.1 Chemical investigationsBesides theborings,thechemical investigationsassociatedwith explorationproject of the kind described here responsibIe for the major part of the expenseinvolved. Thisbeingso, it isdesirabIetouseeverypossibIemeansofworkingeconomically suitabIyclassifyingthe samples.For the evaluation of exploration project for the detection of raw materials forthe cement industry it is, as rule, necessary to know thecontent of eachof thefollowing:

MgO,

Na20, andUnder certaincircumstances it will also necessary to determine the content oforganicmatter inthelimestoneandintheclaymineral component, becauseittendstoundergooxidationinthepreheaterandthus, causingreductionof

giverisetoincrustations whichtendtoclogtheequipment.The samples divided into sections the basis of macroscopic criteria. There is,however, risk that variations which important in connection with quarryoperations planning remainundetected within particular portion for analysis.Forthisreasonthesampleswill preferabIy subdividedintoportionsof 1 mlengthforprocessinginto theactual samples foranalysis. For each of these 1 msamplesthetotal carbonatecontent isfirst determined, inorder thustoobtaininformation the variations of the most important constituents, namely, and2.2.22.2.2.1Mineralogical andpetrographicinvestigationsLimestone20 21Rawmaterials 1. Geoiogy,depositsmethods applied to thin sections. However, for practical purposes of assessingmaterial deposits it is usuallysimpler to obtain this information chemlcalanalysis. .In addition, mineralogical information very useful in predicting the severltyofwearthatwill occurinthecrushingandgrindingmachinery. cases the quickest way to obtain adequate information thecal compositionis examinationof thefine structure of thematerlal.2.2.2.2 ClaycomponentMineralogical and petrographic investigations the clay m.ineral of interest both in the choice of preparatory processing machlnery and In obtalnlnginformation theburningbehaviour of thematerial inthekiln.In both cases the mineralogical form ofthe silica, determined chemical analysis,plays significant part.Large amounts of free quartz will cause heavy mechanicalwear abrasiveaction andwill, incontrast withtheclay minerals, reactiveonlyat hightemperatures.Swelling clays liabIe to cause troubIe in storage and in extraction from storagecontainers stockpiles.Information themineralogical mode ofoccurrenceof alkalies, sulphatesandchlorides providecluestopossibIecirculationsinvolvingthesesubstancesinthecementplant.These investigations most simply carried out methods.Alternatively, differential thermal analysis has proved very suitabIe for thepurpose.2.2.3 Physical investigationsThe physical investigations towhich the rawmaterials subjected usuallycomprise only the determination of the natural moisture content of the freshrockandthemaximumwaterabsorption.Grindability and weartests performed in connection w!th theand designof thecrushing, grindingandotherpreparatory In some cases it is also necessary to determine the particle size distribution of clay sand.2.3 Evaluation of theresults of theinvestigationsThe availabIe results of the investigations should so processed that all variationsinchemical characteristics, workabIequantities, materialsmixture, andtypeofmachinery to used in quarrying the deposit ascertained fromtheinterpretationandevaluationof thedatathatemerge. .It is of major importance that the analyses should yield average values for materlalquantities corresponding to between and five years' production. Largerquantities falsify the overall picture, so that useless parts of the deposits wrongly ratedasuseful.22Explorationprocedure: Evalutionsof theresultsof theinvestigations2.3.1 Geochemical evaluationwithquarryingoperationsplanningThe first step, inconjunction withplanning the quarryingoperations, consistsindetermining the average chemical composition. Then follows the calculation of therawmix composition. With the results of this calculation the proportion oflimestone from the first quarry bIock requiredin the mix determined. thisvaluehas determined, the preciseworking lifeof thebIock calculated.It is possibIe that the composition of the materials, other than limestone, added tothe mix willundergo some change during this period of time, so that shift in themixproportionswill occur. Thismust ofcourse takenintoaccount, sothatduringtheexcavation of the firstbIockit well that variationsinthe dailyquantities oflimestoneproducedwill necessary.Similar considerations apply to variations in the composition of the limestone itself.If, for example, very marly limestone is encountered in fault zone, it will have to ascertained how muchhigher-grade limestone from another part of the quarrywillhave to addedin order to obtain the requiredraw mix composition. It indeed occur that, as result of such changes in the chemical characteristics of thelimestone, theadditionof clay to therawmix entirely dispensedwithforfairlylongintervals.In that case there must of course sufficient plant availabIefor producing, handlingandpreparingtheextra limestonerequired. Thisextrademand for limestone will reduce the working life of the quarry in comparison withtheinitial estimate.If, in such cases, operations planning is based average values over long periods,it occur that the quarry machinery capacity originally provided will turn out to inadequate for daily output requirements in course of time. Under suchcircumstances crusher, for example, compensate for this shortfall in capacityonly workinglongerhourseachday.Suchcalculations showfurthermore that cementplant whichisoperatedwithonly two raw material components in the first few years of its working life asresult of changes in the average composition of the limestone as quarryingproceeds furtherinto the deposit,require additional correctivecomponentsafterseveral years. Alternatively, special arrangements necessary such as,for example, the installation of bypass system to with increasing contents ofchlorideandalkali.Also, thebasisof such evaluationofthegeological investigations, it ispossibIe to direct the quarrying operations in such way that certain masses of rockin whichsome of the constituents exceed the permissibIe limits nevertheless usefullyquarriedandprocessed. For example, varyingthefloor level of bench working intermediatebenchit possibIe so to control theoperationsthat thelimitingconcentrationisnever exceeded.2.3.2 Calculationandclassificationof reservesTheinformationconcerningreserves whichis containedinthe final report of explorationfor rawmaterials intendedfor cement manufactureshouldalwaysrelatetoworkabIe(recoverabIe) reserves.23Rawmaterials 1. Geology,depositsMaterial excavatedfortheconstructionof haulageroads, turningareas, accessramps and safety zones, where production of rock for processing done,should deducted. Also, some allowance for waste or loss in quarrying should made.The total reserve quantity and the working life thereof is obtained simply addingup the quantities in the respective bIocks and the estimatedlives of these bIocks.Such calculationshouldcomprise theprovedreserves.The classificationprocedure for the pit and quarryindustryis generally similar tothat recommended for ores theGesellschaft Deutscher Metallhutten- undBergleute(Associationof GermanMetallurgical andMiningEngineers, 1981)."Proved reserves"(categorycomprise reserves which have the subject ofdetailedexplorationand have fully investigatedwithregardtochemicalfeatures andtheir range of variation,bedding, tectonics, preparatoryprocessing,hydrogeological conditionsandthelegal aspects associatedwithquarryingthematerialsconcerned. Category relatesto"probabIereserves", i. thezoneswhichlieadjacent to depositcontainingcategory reservesandwhichhavealready explored borings to such extent that inferences as to chemicalfeatures, bedding conditions and structure, hydrogeological conditions andpreparatory processing drawn from the experience gainedininvestigatingthecategory reserves.These last-mentioned reserves should ascertained as the result ofthe third stageof explorationproject inconnectionwithwhichthereservesassignabIetocategory arealso estimated."Indicatedreserves" (category 1) determinabIeat theendofthesecondstage of exploration project for cement rawmaterials. These have investigated thebasis of network01 widelyspaced thetypes ofrockandtheir chemical characteristics substantiallyknown, as alsothestructure andbeddingconditionsinbroadoutline.Final'y, the"inferredreserves" (category 2) arethosewhich tentativelydetermined as the result of the first exploration stage, in which the deposit has prospected means of fimited number of individually located boreholes, so thatthe chemical characteristics and structure of the deposit known in approximate andgeneral way.2.4 Organizing explorationprojectThe various activities involved in prospecting for raw materials for the manufactureof cement, as described above, comprise than just the work of the geologist geological institution. order totacklethetasksuccessfully, it isnecessarytoemploytheservicesof teamof expertsfromtheveryoutset. It isespeciallyimportant that this team should include mining engineer and process engineerfamiliar with the cement industry, for only in this way will it possibIe to sure ofavoidingseriousmistakeswhichmight otherwise committedalreadyintheplanning stage of the exploration project. particularly, the participation of theprocess engineer is of majorimportance inorder toensure that thegeochemicalinvestigations properly gearedtothecementindustry'sneeds.24Using computerin explorationproject2.5 Using computerin exploration projectTheevaluationof thegeochemical dataobtainedfromtheexploration substantially speededup means of suitabIe computationsystem.The chemical analyses of the drilled cores stored section section, withassociateddatarelatingtotheco-ordinatesoftheborehole, thedepthandthethicknessof thedeposit. makinguseofappropriateprogramsit ismoreoverpossibIe to store theresultsobtainedfrominclinedboreholes andfromtrial pitsand, with due regard tothe dipof thestrata, to obtain strata-related presentationof thegeochemical conditions.Since the benches in the quarry usuallyhorizontal, the computer via thestandard deviation, determine coefficients of variation and limiting concentrationsfor selected areas of the deposit. From this information the bench height and benchsections theninturn obtained.Thisdatacollection regularly updated andsupplementedwithfurtheranalyses during the subsequent actual quarrying operations, so that pred ictions ofthe chemical composition of the material encounteredin the individualstages ofquarrying reliabIy made.It isalsopossibIetolet thecomputer producemapsindicatinglinesof equalchemical concentration, whichprovideinformationfor determining the directionof quarrying.Calculations of reserves, evaluations of geophysical investigations and analyses ofthebeddingconditions then carriedout.References1. Bender, F. rsg.) : Angewandte Geowissenschaften. - Stuttgart: Enke- Verlag1981.2.Cembureau(Hrsg.): Cement Standards of the world(portland cement and itsderivatives). - Paris1968.3. D1N 18123 Baugrund: Untersuchung von Bodenproben, - Berlinund Beuth-Verlag1971.4. Duda, W. Cement Data Book. InternationaleVerfahrenstechnikenderZementindustrie, 2. Auflage. - Wiesbaden und Berlin: Bauverlag GmbH1978.5. Engelhardt, W. v. / Fuchtbauer, / Muller, G.: Sediment-Petrologie, TI.II:Fuchtbauer / uller: Sedimente und Sedimentgesteine. Stuttgart:Schweizerbart'scheVerlagsbuchhandlung1970.6. Flathe, / Homilius, J.: Geoelektrik. In: Schneider, (Hrsg.): DieWassererschlieBung, 2. Auflage. - Essen: Vulkan-Verlag1973.7. GDMB Gesellschaft Deutscher Metallhutten- und Bergleute (Erzmetall)(Hrsg.):Lagerstatten der Steine, Erden und Industrieminerale 1981.- GDMB, 13392Clausthal-Zellerfeld.25Rawmaterials 1. Geology,deposits8. Kuhl, Zementchemie. - Berlin: Verlagfur Bauwesen1958.9.Schater, - U.: Prospektion aufKalksteinlagersti:ittengezeigt Beispiel zurErkundung von Rohstoffen zur Herstellung von Zementklinker. - In:Aufbereitungs-Technik2. u. 3/1979.10. Schi:ifer, H.-U.: Prospecting Methods in Ceramic Raw Material Exploration.- Interceram. Vol. 28, No. 4/1979.26Rawmaterials 11. 11. Quarrying the raw materials Schuberth1 Guidelines for 281.1 Layout of open-cast operations. 281.2 equipment 292 Overburden. 302.1 Overburdenremoval 302.2 Storage of overburdenmaterial 313 Breakingouttherock 323.1 DrillingandbIasting . 323.1.1 Drillinglarge-diameterholes 323.1.1.1 Single-rowbIasting 333.1.1.2 SurfacebIasting. 353.1.1.3 Drillingtools 353.1.1.4 Drillingmachines 363.1.2 Blasting. 363.1.3 Cost 403.1.4 Tunnellingmethod. 403.1.5 Seriesfiringof small-diameterbIastholes. 413.1.6 SecondarybIasting. 413.1.7 Storage of explosives 423.2 Ripping. 433.3 Stripping 454 Loading. 464.1 Development trend. 464.2 Loadingmachines. 464.2.1 excavators 464.2.2 Hydraulicexcavators . 474.2.3 Wheel loaders . 484.2.4 Crawlerloaders 495 Haulage 505.1 Rail haulage. 505.2 Haulage rubber-tyredvehiclesandothermeans 505.2.1 Heavy trucks 505.2.2 Belt conveyors 525.2.3 Loadand 535.4 Aerial ropeways . 546 Mobile crushingplants . 55271 Guidelines for quarryingRaw materials for the cement industry usually obtained large-scale cast ( open-pit) mining quarryingoperations. Depending theintendedclinker production quantities, quarry outputs may to severalmillion tonnes ofmaterial . Inorder to avoidmisdirectedcapital expenditure ;tis thereforeimperative to obtain reliabIe information the raw material deposit, moreparticularly in terms of quality and quantity. Such information yielded geological exploration is of decisive importance with regard to the conduct of thequarryingoperations. ' addition, however, variousstatutoryrequirementsandobIigations have to fulfilledconcerningtheexcavations themselves, accidentpreventionandenvironmental protection. ' manycasesthesesodominatethepicture that purely economic and technical considerations of winning the materialbecome secondary tosatisfyingthestatutoryconditions. . Rawmaterials 11. Quarrying7 Siterestoration . . . . . . . . . .7.1 The situationinthecement industry .7.2 Quarries andlandscaping.7.3 Restorationfeatures ..7.3.1 Hillsides.......7.3.2 Bermsandquarry faces7.3.3 Final quarry floor7.3.4 Waste tips . . . . . .7.3.5 Settlingponds. . ...7.4 Noiseanddust emission7.5 CostReferences575758585859595960606162Guidelinesfor quarryingthe rock. It will then usually necessary to out the quarrying operations inseveral benches and at several working points simultaneously, so that thecomposition of the raw material controlled. It will only rarely that thedeposit will consist of material having ideal composition for cement manufac-ture, enabIing the quarrying operations to confined to single face and singleworkingpoint. With subsurface quarryingin latitudes it will usually necessary to control the inflow of ground water pumping other means. Thecost of thismustnot underestimated.The various quarry floor base levels should connected to another and tothesurrounding general ground level means of ramps, sothat machines,equipment, operating personnel and repair gangs readily move from levelto another.If the ramps moreover used as haulage roads for heavy trucks, theyshould not moresteeply inclined than 1 in 1 and should sufficiently wide sothat twovehiclestravelling inoppositedirections convenientlypasseachother. Narrower rampsfor single-linetrafficwith passing bays not to recommended except perhaps for small quarries with only few vehicles. The bestdirection of quarry face advanceis alongthe strike of the bed. ' this wayit willmost easily possibIe tomeet thesafetyrequirement that hazardous effects ofrockpressure instabilitymust avoided. If particular reasonsnecessitate different direction of faceadvance, e.g., diagonallyinclined, either ascending descending, the danger of falling rock fromoverhanging parts should counteracted increasing the batter of the working faces. It should also in mind that surface water is liabIe to collect , and off along, such bedding partingplanes, thus forming possibIe causeofrockslips.The height of the working face is, for example in the Federal RepubIic of Germany,subject to statutory regulations with regard to permissibIe maximumvaluesdepending the method of quarrying the size of machines used. The slope andwidth ofthe benches should suited to the nature and stability of the rock and tothemethodof quarrying.1.1 Layout of open-cast operationsThe most widely used method of quarrying is based the conventional benchingtechnique, inwhichthematerial inthedeposit isquarriedinseveral benchesC'steps"), above the other, with predetermined heights of face. If the depositis located above the level of the cement works, thus involving "hillside quarrying",it isadvantageoustousethemaximumpermissibIefaceheights, becausethematerial broken out of the face falls gravity to thehaulage level, . g.,if large-holebIastingisemployed. Therestrictingconditions faceheightmay theaccessibility of the top part of the face the attainabIe bIasthole drilling depth.Conversely, with"subsurface quarrying",i. . , if the deposit islocatedbelow thelevel of the cement works, it will generally advantageous to work with relativelylow faces, so as to keep to minimum the expensive work of raising the quarriedmaterialfrom the workingfloorlevelto thelevel of the surroundingground.Thelowfaceismoreover advantageous incaseswherequarryinghasto doneselectively in order to compensate for variations in the chemical characteristics of281.2 equipmentThe mechanical equipment of the quarry, more particularly the number and size ofthe machines, will depend the intended rate of production and the haulagedistance. With regard to the economy of the operations it , roughly speaking, saidtoimprove withincreasing size of themachinesemployed, providedthat sufficiently high rate of production in the quarry will correspondingly highdegree of plant utilization to achieved.ln many cases, however, fulfilmentofthisrequirement is restricted quality considerations, more particularly when certain constant average quality ofthe outputfrom the quarry has to obtained thecontrolledcombiningof variousgrades of rock.Of especial importanceis the interadjustment of themachines employed,i. . , ensuringthatthey dulysuitedtofunctionefficientlywith another,moreparticularlyin theoperations of loading, haulageandcrushing.Thus, theloadingmachineshould sosuitedtothehaulagetrucks, andviceversa, that thenumber of loadingbucket operatingcyclesfor filling truckis29Rawmaterials 11. Quarryingbetween three and eight, the larger being applicabIe to the smaller bucket.From th.e economic P?int of view it is important not to allow the capital tied inthe and gear of the vehicles to remainidle for toolongperiods.Theymust theirkeep! the other hand, the receiving capacity of the crusher shouId large enough to thefullof haulagetruckdischargedinjust dumping the sizeof therockpilefragments fedtothecrushershould solargeas tocausejamminginthefeedopening.In plannlng the quarry, the need for providing intermediate storage directly before after the primary crusher should considered.Such buffer capacity makes therate of quarrying to some extent independent of the rate of further processing and thus invaluabIe in maintaining continuity of supply in the event oftemporaryhold-upsinquarryingactivities(seealsoChapter 111).2 OverburdenIt will only seldom that rawmaterial depositisnot covered layer of that the overburden directly excavated and processed alongwlth the actualdeposit because the chemical composition fitsin withthat of theraw mix case the overburden will have to removed separately fromthem.aterlal ofdeposit. It will either haveto dumpedasunprocessabIewlth unwantedinclusionsandimpuritiesfromthedepositItself) stockpiled, so that it reclaimedin controlled quantitiesandmixedintheright proportionwiththemainmaterial fromthedeposit.2.1 OverburdenremovalThe method of removal will depend thefollowing factors relating totheoverburden:strengthandhardness; soil solidrock;thicknessof the haulagedistance;loadbearingcapacity;susceptibility toweathering.Prov.ide.d that rock overburden suitabIy broken drilling and bIasting thefollowing conventional types of machine usedfor itsremoval:backactingexcavator (back-hoe);dragline excavator;bulldozer. general, theground surfacewhich isas yet intact will, account of its have better bearing capacity for loads than ground that has already hadItStoplayer removed. Asindicated, thepreferredmachinesfor topsoil digging- nowadays mostly with hydraulic controls- the backacter and the dragline.30OverburdenThe backacteris better to removeunconsolidatedmaterial from fissures,crevices dolines(swallow-holes). the other hand, the dragline has largeroutreach and greater digging depth. Besides, the dragline bucket, suspended loosefromits swerve to miss obstacles roughrocky surface, so that theexcavator is not subjected to excessive wear and tear. If the material to handledis fragmentedrock,thepieces will have to fairlysmall, however.Withboth types of excavator it is necessary to use some form of haulage machineforremovingtheexcavatedoverburdenmaterial. most cases, varioustypes oftruck used for suchpurposes. Multi-axle articulated dump trucks withmulti-wheel drive have found most suitabIe because of their good manoeuvrability thegenerally badground whichthey havetotravel. Alternatively, theexcavated material loaded, via suitabIe feed devices, onto belt conveyors incases where these economically usedin order to withlarge handlingquantities tomeet otherrequirements.Thebulldozer suitabIy used as meansof overburdenstrippingif thehandling distances not too great, if there is only limited thickness ofoverburden if highly cohesive soilleaves alternative to this method withoutnecessitating extensive additional measures (construction of roads).