Technological Changes in the Cement Manufacturing Industry. By- Wesson, Carl E

REPOR TRESUMES

ED OM 582 VT 003 669 TECHNOLOGICAL CHANGES IN THE CEMENT MANUFACTURING INDUSTRY. BY- WESSON, CARL E. CALIFORNIA STATE DEPT. OF EMPLOYMENT, SACRAMENTO BUREAU OF EMPLOYMENT SECURITY, WASHINGTON, D.C. PUB DATE OCT 66 EDRS PRICE MF-$0.25 HC-$1.32 31P.

DESCRIPTORS- *TECHNOLOGICAL ADVANCEMENT, *AUTOMATION, *CEMENT INDUSTRY, JOB ANALYSIS, COMPUTERS, EMPLOYMENT TRENDS, EMPLOYMENT OPPORTUNITIES, *OCCUPATIONAL INFORMATION,

THE PURPOSE OF THIS STUDY IS TO PRESENT A PRELIMINARY PICTURE OF OCCUPATIONAL CHANGES BROUGHT ABOUT IN THE MANUFACTURE OF CEMENT AS A RESULT OF INTRODUCING AUTOMATED EQUIPMENT. ONE AUTOMATED AND SEVERAL CONVENTIONAL TYPE CEMENT PLANTS WERE STUDIED. ANALYSIS OF DATA OBTAINED THROUGH RESEARCH AND DATA COLLECTED DURING THE STUDY REVEALED THAT MANUFACTURERS OF CEMENT, LIKE THOSE IN SO MANY OTHER INDUSTRIES, ARE AUTOMATING THEIR MANUFACTURING PROCESSES. THE CEMENT INDUSTRY IS GOING THROUGH ONE OF THE GREATEST REMODERNIZATION ERAS THAT COULD BE EXPERIENCED BY ANY INDUSTRY. INFORMATION IS PROVIDED ON THE OCCUPATIONAL STRUCTURE OF THE CEMENT PLANT BEFORE AND AFTER INTRODUCTION OF A COMPUTER CONTROL SYSTEM, THE JOSS ELIMINATED AND NEW JOBS CREATED, THE KIND OF WORK THE NEW JOBS ENTAIL, THE KINDS OF KNOWLEDGE AND SKILLS THE NEW JOBS DEMAND, AND THE SOURCE OF WORKERS FOR FILLING THE NEW JOBS. HISTORICAL MATERIALS, *PROCESS FLOWCHARTS, AND OTHER PERTINENT INFORMATION ARE PRESENTED FOR EACH PROCESS IN THE AUTOMATED PLANT DESCRIBED. CHANGEOVER TO AN AUTOMATED SYSTEM IN THE ABC CEMENT COMPANY INDICATED A DECREASE IN EMPLOYMENT OF ABOUT 13 PERCENT. AVERAGE PRODUCTION WAS INCREASED. (PS) United States Employment Service October 1966 Technological Changes in the Cement Manufacturing Industry

Department of Employment State of California

U. S. DEPARTMENT OF LABOR CALI FORM A STATE EMPLOYMENT SERVICE W. WILLARD WIRTZ, SECRETARY ON idled ii ith U. S.1 m No\ nic IIISe'ri'icc

MANPOWER ADMINISTRATION Edmund G. Brown 1UREAU OF EMPLOYMENT SECURITY Governor C.0 WASHINGTON, D. C. 20210 (I) .1 lbert B. T ieburg Director C U.S. DEPARTMENT OF HEALTH, EDUCATION & WELFARE

OFFICE OF EDUCATION

THIS DOCUMENT HAS BEEN REPRODUCED EXACTLY AS RECEIVED FROM THE

PERSON OR ORGANIZATION ORIGINATING IT.POINTS OF VIEW OR OPINIONS

STATED DO NOT NECESSARILY REPRESENT OFFICIAL OFFICE OF EDUCATION

POSITION OR POLICY. TECHNOLOGICAL CHANGES IN THE CEMENT MANUFACTURING INDUSTRY

CALIFORNIA STATE EMPLOYMENT SERVICE DEPARTMENT OF EMPLOYMENT ALBERT B. TIEBURG, Director TABLE OF CONTENTS

Page Foreword

History of Cement 1

Processes in the Manufacture of Cement: Traditional Procedures 2 Isometric Chart: Processes in the Manufacture of Cement 4

Discussion of Computer Control System 5 Processes in the Manufacture of Cement: Automated Procedures 6

Staffing Requirements 12

Jobs Created by Installation of Automated Equipment 13 Arrangement and Content of Job Descriptions. 14 Job Descriptions and Worker Requirements 15 Summary 21 Bibliography 22

Index of Occupational Titles 23 Appendix 24

iii FOREWORD

The purpose of this study is to present a preliminary picture of occupational changes brought about in the manufacture of cement as a result of introduction of automated equipment. In investigating the changes that occurred in the plant, the questions formu- lated were restricted to providing information in the following areas: occupational structure before and after introduction of the equipment; the jobs dis- placed and new jobs created; the kind of work the new jobs entail; the kinds of knowledge and skills the new jobs demand; and the source of workers for filling the new jobs. The findings of the study relate only to the automated plant described and do not necessarily reflect the experiences of other plants in the industry. His- torical material, process flow charts, and other pertinent information are presented for each process to provide for a better understanding of the processes discussed. Additional data for the study was obtained from conventional-type cement plants and from articles and other secondary sources. Although this study is limited, we believe that even with its limitations it can be helpful to public employment offices and others through adapting the information it contains to similar situations and circumstances in their own com- munities. The study was prepared by Carl E. Wesson, occupational analyst, under the supervision of Kenneth J. Bohn, field center supervisor of the California Occu- pational Analysis Field Center of the California State Employment Service in cooperation with the Branch of Occupational Analysis of the United States Employment Service. Grateful acknowledgement is made to the organizations and their staff who cooperated in the preparation of this brochure. Without their contributions and assistance it would not have been possible. HISTORY OFCEMENT Ever since man started to build, at the dawn of quarries on the Isle of Portland, England. Joseph Asp- civilization, he has searched for better bondingagents din is given credit for making the first portlandce- with which to hold together the rocks andstones used ment, and he is generally recognized as the father of in construction. The Egyptians used impuregypsum the modern portland cement industry. 2 plaster as mortar in pyramid construction. Slaked lime Aspdin appears to have been the first to realize that was used by the Greeks, and the Romans probably superior hydraulic propertieswere obtainable by learned of its utility from them. Both the Greeks and harder burning, that is, to proper fusion, instead of Romans made a pozzolanic mortar by mixing finely solely by calcination aswas long the practice. How- ground volcanic material with lime, sand, andwater. ever, he followed the previous practice of pulverizing Pozzolana hardens by reacting chemically with the by slaking and removing by hand larger pieces ofun- lime. The name derives from the Italiantown Pozzuoli, slaked harder-burned clinker. It remained for Isaac where a suitable volcanic tuffwas found. The Romans Johnson to discover, about 1845, that the harderpar- also used powdered pottery fragmentsas pozzolana. ticles after weathering and suitable mechanical grind- The pozzolanic cements made by mixing suchmate- ing yielded a cement of superior qualities. Johnson, rials with lime and waterwere found to be resistant if therefore, is more nearly the discoverer of theport- exposed to water, andwere for a long time the only land cement we know. cements known to be suitable for such exposure. The cement industry in this country began with Pozzolanic cement was used in such structuresas the the discovery in 1818 of a natural-cement rocknear Pantheon, the famous Appian Way, the great system Chitenango, New York, by Canvass White, an engi- of aqueducts, and the Colosseum. neer on the Erie Canal. In 1825 cement rock was found Despite the early use of these materials, littlewas in Ulster County, New York, and in 1828a mill was known of their chemistry, andno substantial advance built in Rosendale, New York. In the spring of 1866 was made in the manufacture of lime and cement from three men from Allentown, Pennsylvania, formed the the time of the Romans until 1756. In thatyear John Cop lay Cement Company and locateda mill near that Smeaton, who had been employed by the Englishgov- city. Mr. Saylor, one of the partners, beganto experi- ernment to build a lighthouse in the English Channel, ment on portland cement from the rock in the quar- discovered that an impure or clayey limestone, when ries. After a great number of experiments,true port- burned and slaked, would harden intoa solid mass land cement was produced in 1875. Thiswas the small under water as well as in air. This discovery of beginning of the American portlandcement industry. Smeaton's led the way to rapid improvement and development in the lime and cement industries. Modern portland cement is a finely pulverizedma- In 1796 James Parker, of Northfleet, Engl&nd, ob- terial consisting principally of certain definitecom- pounds. tained a patent for the manufacture ofcement, which he aptly named "roman cement." Parker'sprocess Methods of production have naturally changed consisted of burning certain stoneor clayey products greatly over the years. Early firing was in stationary, called "nodules of clay" inan ordinary limekiln, and intermittently operated kilns. Productionwas on a then grinding the clinkers toa powder. Cement made small scale and the cementwas ground with millstones. in this way did not absorbwater and crumble. The Kilns underwent various changes, but the most strik- process rapidly gained favor among engineers and ing was the introduction of the rotary kiln. In 1877 builders, and natural-cement plantssprang up all over T. R. Crampton obtained a British patenton a rotary the continent of Europe, in England, and later, about kiln process for cement, but itwas not a success. 1818, in the United States. Frederick Ransome obtained British and U.S. patents in 1885 and 1886 for a process that achieved first In 1824 Joseph Aspdin took outa patent in England suc- for the manufacture of cess in the United States and led eventually to com- an improved cement, produced plete adoption of the rotary kiln for production of by calcining a mixture of limestone and clay. To the portland cement in this country. In Europe the resulting powder he gave thename "portland cement," con- because when it hardened it produced tinuously operating shaft kiln has remaineda com- a yellow-gray petitor. mass resembling in appearance a stone found in various 2 Calcination: A process in which volatile material, such as carbon dioxide, 1 Clinker: The product resulting from calcining raw, pulverized stone in is expelled from limestone by the application of heat to reduce the a kiln of a cement plant to a point of incipient fusion. limestone to a powder.

1 PROCESSES IN THE MANUFACTURE OF CEMENT

TRADITIONAL PROCEDURES The basic steps in the manufacture of cement are as material leaves the primary crusher in pieces no larger follows: than seven inches in diameter. 1. Excavation of raw materials Depending on the moisture content of the raw ma- 2. Transportation of raw materials to plant terials, they are either passed through a drier prior to 3. Crushing of raw materials the secondary crushing process, or dried from the 4. Blending of raw materials heat generated in the secondary crushers. 5. Pulverizing raw materials The crushed materials are then fed into the second- 6. Burning raw materials to produce clinker ary crushers to further reduce materials to % to 1/2 7. Grinding of clinker into cement inch in diameter. These secondary crushers are of a type called hammer mills. The hammer mill is a steel Cement is manufactured by the wet or dry process. cylinder inside of which are a number of heavy pieces Factors such as source and type of raw materials, of steel anchored to a revolving metal shaft. As the moisture content of raw materials, cost of fuel and shaft revolves, the free ends of the "hammers" fly out- power, and the availability of water and waste-water ward and crush the rock against a metal breaker plate disposal facilities dictate the type of process used and and grid. The crushed rock leaving the hammer mill sequence of steps in processing materials. is passed over a vibrating screen allowing rock of small sizes to pass through while the oversize rock is Excavation returned to the mill for further reduction. The usual The excavation of raw materials is the first step in size of the rock leaving the secondary crusher is from the manufacture of cement. Raw materials are exca- %to Y2 inch in diameter. The crushed materials are vated by quarrying or digging from open pits, mining then conveyed on belt conveyors to stockpiles, bins, from underground workings, and dredging from de- or silos for storage. posits covered by water. Primary and secondary blast- After the materials have been crushed, representa- ing is required in quarrying operations. Holes are tive samples of the materials are taken, ground in lab- drilled into the bed or rock and charges are placed oratory mills, and analyzed to determine their chem- and fired to break up the rock mass. When the size of ical properties. From this analysis the proportions of the blasted rock is such that it cannot be handled, it each type of raw material needed are computed by an must be broken up further by additional drilling and algebraic equation. secondary blasting. Materials such as clay and shale do not require blasting and are excavated by means of Raw Grinding (Pulverizing) and Blending power shovels of various types. Mining from under- The crushed materials are then drawn from storage ground workings is performed in a manner similar to in the proportions specified so that the cement made mining coal. Deposits of marl, oyster shell, or sand from them will be of the right composition and uni- covered by water must be recovered by floating form quality and conveyed to the grinding mills for dredges of thehydraulic,dipper,clamshell, and raw grinding. Up to this point the processes to pre- bucket-ladder type. pare the raw materials have been essentially the same whether the plant uses the dry or wet process. The Transportation materials are blended and ground in the same operation in either process. However, in the wet process, After the materials are excavated they are trans- water is introduced into the mill along with the ma- ported to the processing plant on dump trucks, rail- terials. The mills used for milling the materials in road gondolas, mine hopper cars, ships and barges, or either the wet or dry process are the same type. The by belt or bucket conveyors. Most plants are located primary mill is a ball mill, and the secondary mill a near the source of raw materials. tube mill. Sometimes these mills are combined into a single mill, called a compartment mill. In the dry pro- Crushing cess the materials arc generally fed into the kiln feed The primary crushing of quarried materials is per- bins after they are milled.Inthe wet process the wa- formed in one of three types of processing machines ter-mixed material (slurry) is pumped to slurry basins rotary crushers, jaw crushers, or roll crushers. The by centrifugal pumps, Sedimentation and segregation

2 of the slurry is prevented by constant agitation. Me- inch per foot of length) and rotate at a speed of chanical agitators, compressed air,or combination from 50 to 90 revolutions per hour. The combustion mechanical-air agitators continually agitate the slurry. of coal, gas, or fuel oil at the lower end of thekiln A unique illustration of the extreme flexibility of wet provides the temperatures required for incipient fusion processing is the application of flotation to remove of the materials. The temperatures at thelower end undesirable or unneeded constituents in the raw ma- of the kiln range from 2600° F. to 3000° F. terials, thus making possible utilization of material The raw materials, either dry or wet, are fed into sources which otherwise would beuseless. However, the kiln at the upper end of the kiln. As thekiln dry processing has its advantages also, namely greater revolves the materials roll and flow toward the lower fuel economy with shorter, therefore less expensive, end. As the materials flow toward the lower end they kilns. encounter higher and higher temperatures.Gases are driven off between 2600° F. and 3000° F., and in- Burning cipient fusion occurs forming small, glossy, hard balls of a new substance. This substance, called clinker, is Allof the processing operations up to this point are cement when ground to powder.Maintaining almost to prepare and blend the variousmaterials for burning constant conditions, such as rate offeed, rotation of in the kiln. This is the key process in the manufacture kiln, temperatures and pressures, is necessary to pro- of cement and the kiln must be controlled with the duce a uniform clinker. The clinker emergingfrom greatest of care to produce a uniformproduct. Two the kiln is cooled by air coolers and conveyed by pan shaft kiln used types of kilns are used: the vertical or and belt conveyors to storage. during the infancy of the cement industry, and still used in Europe in modernized versions; and the rotary kiln, used almost exclusively in the cement industry in Grinding (Finish Milling) the United States. The final step in manufacturing cement is the grind- The rotary kilns vary in diameter from 6 to 181/2 ing of the clinker into a very fine powder.Ball mills feet, and in length from 60 to 610 feet. Wet process and tube mills of the type used in millingthe raw kilns are somewhat longer than dry process kilns inas- materials are used to perform this function. After the much as from 1/4 to 1/5 of the length is required for finished cement leaves the finish mills it is conveyed drying or evaporating the water from the material. by pneumatic pumps to storage bins untilpacked or The kilns are inclined a few degrees (about 1/2 to 3/4 shipped in bulk.

3 MANUFACTURE OF PORTLAND CEMENT Isometric Flow Chart OVERBURDEN /4 LAST HOLE SHALE,COMBINATIONS OYSTER OF SHELLS, LIMESTONE, RAW MATERIAL P>,, SLURRYPUMP...77 -WASH MILL CLAY (TOP SOIL DRILLING RIG EXPLOSIVESSLAGCLAY, K4ARL.& SILICA IRON SAN ORE, MAGAZINE 1 4/ 40:ces7 64; 411' s r /%' CLAY TRUCKDUMP CLAY PIT te ELEVATOR SHOVELPOWER VIBRATING SCREEN CC-AY £. ROCK DRYER I VIBRATING SCREEN FEEDER-1'SLURRY 401 4 0 SLURRYSLURRYBASINSTORAGE POWERSHOVEL 4.1 TRUCKDUMP HAMMER e;A.r PROPORTIONING ...- - - TUBEMILL *I MILLBALL ADDED R6 EQUIPMENTPORTIONING 400 PULVERIZED COAL, OIL OR GAS FUEL MILL SA- %. NO TUBE MILL ; 4. \ VERTICALGRINDING EQUIPMENT ,AN.0 _kG 4.0.011m, "Nt..0-- 41111%, 1.10\ PUMP RAIL DELIVERY OF SH MILL 0, /I Go, IRON ORE, SLAG, SILICA SAND. GROUND RAW BLENDING SILOS, DRY MIXING S.. .01 I I, PNEUMATIC-SEPARATOR (tXt* 44 .10Mi reWiri ct) > CLINKER STORAGE GYPSUM & FUEL STORAGEMATERIAL I (1 s*..f-IPUMP TANKSAND BLENDINGSLURRY MIXING PUMPPNEUMATIC '1441h SLURRYPUMP RK FLOW OF' COOLARCLINKER TUBEMILL BALL MILL CLINKER j--GYPSUM STORAGE SLURRY BASINS /0- HOT GASES 'C I I 1:-:-.S.-EPAARIARTOR EQUIPMENTPROPORTIONING 1111111 \N. /44,-., FEEDERKILN 90C REPAIR SHOP ROOMSLOCKER ' ISPORTLAND SHIPPEDLOADING CEMENT IN BAG5....// BULK FOR *\°' OFFICELABORATORY Ex, STACK COLLECTOR DUST RAWFLOW MATERIAL OP STOREROOM AND IN BULK Scale el he! SAFETY TROPHY FLAG & MMMMP3Z-9MM'ErAMMse.StMM.MUMse:MM.=-t.MM.Sr.-IIMM 11 N. no SUB-STATION 33 West Grand Avenue Portland Cement Association Chicago 10, Illinois DISCUSSION OF COMPUTER CONTROL SYSTEM Theuse (or operation) of thecomputer control rate. The equations in the regulation program are systemcan best be explained with adiscussion. time-dependent, and they include the history of meas- urements and control actions. A variation in the feed Blending rate, for example, that occurred hours before (and The computer is used to assist in making the cal- is long forgotten by the operator) is used by the con- culations; using linear programming techniques to op- trol system to eliminate its adverse effect on clinker timize both raw material 'selection and pile composi- quality. The calculations and manipulations of data tion. The computer is "told" the analysis of the raw performed just before the set points are readjusted mix desired. This remains in the "memory" of the would require half a day if done by an engineer with machine until the pile is complete. Analyses of the a desk calculator. The computer performsthis cycle materials going into the pile and their costs are stored every five minutes. At the same time the flexibility of up by the machine. Finally the computer is asked the computer control system allows these calcula- how to combine to obtain the desired mix at the tions to be based on all pertinent data, including that lowest cost. The computer is usually asked to solve the blending problem once a day. received from the kiln instrumentation and from the laboratory analysis. Controlling Kiln Finish Milling Acomputer program is written for the control and regulation of the kiln. This program is designed The computer continuously records data from the to maintain the manipulated variables at levels which ball mill instrumentation. These readings are then will keep burning-zone conditions constant. used to calculate those operational changes which With its memory and ability to act at high speeds must be made to maintain clinker grinding at maxi- the computer can keep the kiln at desired production mum efficiency under all conditions.

os, PROCESSES IN THE MANUFACTURE OF CEMENT

AUTOMATED PROCEDURES

Crushing Central Control The crushing system is operated by the CRUSHER The nerve center of the plant is central control OPERATOR who where the CENTRALCONTROL OPERATOR and the ASSISTANT CENTRAL OPERATOR CRUSHER OPERATOR r CENTRAL-CONTROL OPERATOR Controls the operation of primary and secondary ASSISTANT CENTRAL-CONTROL OPERATOR crushers and related equipment from a panelboard. He presses switches and buttons to start in pre- Control the operation of conveyor system, feeders, scribed sequence such equipment as primary and raw grinding mills, rotarykilns, finish mills, and secondary reducing mills, vibratory screens, con- auxiliary equipment to process the material from veyor feeders, and conveyors. During the operation storage silos into finished cement.The worktzs he monitors the panelboard and equipment. serve closed-circuit television,electronic and eke- trical recorders and indicators, and read printouts from a computer to detect equipment malfunctions The materials are dumped directly into the primary and to determine _operating efficiency. crusher from quarry dump trucks. A 60-inch gyra- tory crusher accepts huge rocks from the quarry weighing as much as nine tons, and in minutes its Translated into mathematical language of the com- powerful, continually gyrating pestle crushes the huge puters, the entire process ofcementmaking is pro- rocks against the manganese steel side plates, reducing grammed into an "on-line digital computer," thus them in size to pieces of less than six inches in diam- becoming a continuous in-line, integrated materials eter. This crushed rock then drops into a surge bin processing and handling system. The result is that the where it is fed onto an automatic conveyor by a plant is completely automated for maximum efficiency, vibratory wobbler feeder. This feeder allows the finer increased output, and constant quality control. Each pieces of rock to be deposited on the belt conveyor plant area and operation has its own controlpanel, first, thereby cushioning the belt, before the larger arranged clockwise around the control room in order pieces are fed upon it. The belt conveyor conveys of material flow. A schematic diagram with indicator the crushed materials to a screening tower where it is lamps shows process and material routing at all times. deposited onto a closed loop screening system. The Controller recorders, electronic and electrical instru- rock that is crushed to less than 3/4 inch in diameter mentauon, and closed-circuit televisionfurnish a con- (called fines) passes through the screens and is dis- tinuous record of process behavior and computer charged onto conveyors leading to rock-storage facil- action, as well as data for engineering studies. All ities. Oversized rock (larger than 3/4 inch in diameter) instruments, switches, and control button sections of is fed into two 600-horsepower hammer mills where a the panels have "manual-auto" sw itches to permit, op- series of hammers hinged to a central axle act like eration independent of the computer. whirling sledges to further crush the rock until it is small enough to pass through the fine screens. The Blending hammers are equipped with electronic sensors that The directions for blending crushed rock are printed automatically control the rate of feed into the sec- out by the computer fromthe information obtained ondary mills. If the feed is too great for the mills to from the rock analysis of materials performed in the crush the materials, the sensors send a signal to the laboratory, and from the tonnage of rock being proc- vibratory feeders to slow down the tonnage until the essed as indicated by automatic .weighing scales. The hammer mills can handle the feed. As the crushed printout designates the type and composition of mate- materials are conveyed to the rock storage silos, sam- rials required to obtain the specified chemical compo- ples are taken from the conveyor for laboratory sition for the manufacture of cement. Controls are set analysis. by the operator to add these materials to the crushed

mfr. 4. L.a. .4 rock on the belt conveyor as it conveys the materials of the kiln, kilns operated by manual control are sub- to rock storage from segregated-rock storage bins. ject to human error, By placing the operation of the When the materials reach the 80,000-ton rock storage kilns under computer control and electronic instru- building, automatic trippers deposit the materials in mentation that constantly transmits all operating data layers as the trippers move back and forth. to the computer, the factor of human error is in a large sense eliminated. The computer analyzes the data Blending and Final Adjustment of Raw Mix and with operating specifications in the memory banks The final blending and adjustment of the raw mix prints out the adjustments to be made. The finely prior to grinding is exercised by withdrawing mate- ground raw materials are fed into the high end of the rials from any or all of eight 2,000-ton silos. The kilns (kilns are 490 feet long, 13 feet wide, and slope material is withdrawn from selected silos by vibrating 7/17-inch per foot from high end to low end). As the feeders over automatic scales onto the belt conveyor kilns rotate (1/3 turns per minute) the finely ground system leading to the raw grinding mill feedbin which raw material rolls and slides toward the low end of is capable of storing 150 tons of material. Adjustments the kilns. The materials are exposed to higher and are made by the operator by varying the flow rate of higher temperatures as they travel toward the low any one of the vibrating feeder-belt scale combina- ends of the kilns. During the two hours it takes the tions in the system. material to travel the length of the kilns, the materials are dried, heated, calcined, and clinkered. The materials first become incandescent and change in color Raw Grinding from purple to violet and finally to orange. As the The grinding of the raw materials into kiln feed heat increases, carbon dioxide and other gases are is the next process. The feed of materials into the ball driven off and the original limestone, shale, clay, and mills from the mill feedbin is controlled by a vibratory iron oxide are changed into other minerals, such as feeder which discharges the blended materials into dicalcium and tricalcium silicate, tricalcium aluminate, two huge ball mills containing thousands of forged- and tetracalcium aluminoferrite. This incipient fusion steel grinding balls measuring from one to four inches takes place in the lower third of the kiln at a tempera- in diameter. As the ball mill rotates, these balls are ture of 2700° F. The new minerals called clinker pass carried part way up the side by steel ridges along the over grates through which air is forced by centrifugal interior of the mill,, The balls then cascade down on fans to cool the clinker. The clinker is then broken the raw mix pulverizing it until itis about 1/1300 into marble-size fragments by chunkbreakers and fed inch in size. onto vibrating conveyors which move it to clinker storage. Homogenizing Raw Mix Into Kiln Feed The fine-powdered materials from the raw grinding Clinker Storage mills are then pumped into homogenizing silos. As the The cooled clinker conveyed from the kilnsis raw mix is being pumped to the homogenizing silos, an stored in huge sectional bins having a capacity for analysis of the composition of the mix is made. Each silo floor is divided into four sections or quadrants, storing 350,000 barrels of clinker and over 7,000 barrels kind low-pressure compressed air, fed from the bottom, of gypsum. A worker operates a bridge crane equipped causes the dry powdered material to flow .upward with a six-cubic-yard clamshell bucket to move and. almost like a liquid from one section to another. In this stack the clinker or gypsum ready for delivery to manner a rollover action is created within each quad- the finish mills. rant. Each quadrant is rotated on a regular time cycle controlled by a timer in the central control room. The Finish Milling materialsarecompletelyhomogenizedandthen The finish-milling system is similar to the raw grind- pumped by pneumatic conveyor to the kiln feed silos. ing system in that the mills are ball mills. However, these mills are longer and are charged with 160 tons Burriing of forged-steel grinding balls. It is at this stage of the All the preceding processes were performed to pre- process that gypsum is added which regulates the pare a kiln feed of highest quality anduniform chem- setting time when cement is used to make concrete. ical composition. The burning operation is the heart The proportions vary according to use, but in general, of the cement manufacturing process, and the more 3 percent to 5 percent gypsum is added to the clinker control that can be exercised over this operation the as it is milled. Automatically controlled conveyors are better the product can be manufactured. Because of used to keep the feedbins continuously filled, and vi- the large number of operating variables, such as rate brating feeders and load-cell belt scales control feed of feed, ratio of fuel and air, temperature, and rotation rate and accurately proportion gypsum and clinker.

7 1111=11

Chart I. CRUSHING SYSTEM'

Raw Materials From Quarry

Vibrating Screens

CRUSHER OPERATOR

Sampling Stations

Segregated Mixed Rock Rock Storage Storage

$ This and subsequent material -flow diagrams indicate the directional movement of the material being processed. INOMPINIMW,-.1.110-1/WW.P.ORMR.M.C7.3.117,

v. IMUMNII111

Chart ILCOMPUTER-CONTROLLED PROCESSES FROM CENTRAL CONTROLROOM

Raw Materials From Crusher System

Segregated Mixed Rock Blending Rock Silos Storage Storage

Raw Mill Feed Bins

Raw Mill Feeder CENTRAL CONTROL ROOM CENTRAL CONTROL OPERATOR AND Raw Mills ASSISTANT

Homogenizing Silos

Kiln Feed Silos

Kiln Kiln Rotary (linker Clinker Feed Kilns Cooker Storage Bins Feeder

Finish Finish Finish Mill Mill Feed Mills Feeders Bins

Cement Storage Silos

9 Bulk Cement Storage then moves controls to position loading spout and to The bulk cement storage system is the last of the operate scales. The operator then selects the loading operations controlled from the central control room bin containing the type of cement specified and starts by the CENTRALCONTROL OPERATOR. The pumps and conveyor systems to draw bulk cement storage system consists of 35 silos having a total capac- from the loading bin and pumps the cement into the ity of storing 400,000 barrels of cement. The entire railroad car or truck. Weights are automatically typed silo complex is interconnected by a system of elevators, on dray tickets or bills of lading. air slides, and pumps so that cement from the finish Each storage silo is equipped with a conveyor sys- mills can be directed to any silo or series of silos. tem and feeders that are electrically operated. The switches that control the operation of this equipment Bulk Handling and Loading are mounted on the control console panelboard in the scale room. These switches, however, are always After the finished cement has been stored in silos, locked and can only be unlocked by supervisory per- all control exercised by the CENTRAL-CONTROL sonnel from the packhouse or laboratory departments. OPERATOR ends. The automated bulk-handling and Whenever the packhouse silos or the bulk-loading bins loading functions are controlled by the LOADING- need refilling, supervisory personnel designate the stor- AREA OPERATOR, who age silo from which the cement is to be withdrawn and unlocks the interlocking selector switch. The op- LOADING AREA OPERATOR erator is then able to start the conveyor system, open air slides, and pump the cement to either the pack- Controls the operation of weighing hoppers and house silos or bulk-loading bins. With this system, feeder and conveyor systems from panelboard to cement may also be recirculated from one silo to weigh and load finished cement into tank trucks or another or between several silos. railroad cars, transfer cement to packhouse silos, or to recirculate cement between storage silos. He Packing pushes buttons and turns controls to operate equip- The packing of cement is still done in the traditional ment and monitors panelboard to determine opera- manner. Bags have self-sealing filling valves and and tion efficiency. when the valve of the bag is placed on the filling spout, 94 pounds of cement is automatically forced into the bag. A lever is then tripped by the worker The bulk-loading facility has two drive-through and the filled bag of cement is discharged onto con- scaleways equipped with seven-foot platform scales. veyors leading to any of four preselected shipping sta- Railroad cars or trucks are loaded with cement and tions. Twelve to 15 bags of cement are packed every weighed on the scaleways. The LOADING- minute. One of the shipping stations is equipped with AREA OPERATOR directs the LOADING-AREA automatic palletizing equipment. This equipment auto- HELPER to spot a railroad car or truck on the desig- matically stacks a specified number of bags on a pallet nated scale and under the loading spout. The operator ready for shipment.

10 Chart HI.BULK LOADING AND HANDLING

Storage SON

Bulk Loading Packhouse Bins

LOADING AREA OPERATOR

Sacking

Palletizing 111 Tank Railroad Shipment Tracks Cars '617 41i

11 STAFFING REQUIREMENTS

Conventional-type cement plants were studied to requirements of a conventional-type cement plant. The provide a picture of staffing requirements. Staffing can staffing of the plants reflect only the occupations that best be illustrated by comparing the staffing require- are directly concerned with the processing stages in ments of the automated cement plant with the staffing the manufacture of cement.

. ,

JOBS REQUIRED JOBS REQUIRED PROCESSES CONVENTIONAL PLANT AUTOMATED PLANT r Primary crusher operator Secondary crusher operator Crusher operator CRUSHING Secondary crusher helper Crusher oiler Reject operator I Oiler

Raw miller Raw miller assistant Car dumper operator Screenman Crane operator Kiln burner BLENDING, Assistant kiln burner RAW GRINDING, Kiln oiler Central- control operator BURNING, Kiln drier tender Assistant central-control operator FINISH MILLING Cooler dragman Grinding unlityman Flue chamberman Overhead craneman Finish miller Ball miller Bin tender Poidometerman Tunnelman Feederman Laborers

Siloman BULK LOADING F.K. pump operator Loading-area operator AND STORAGE Bulk loader Loading-area helper Laborers

12 JOBS CREATED BY INSTALLATIONOF AUTOMATED EQUIPMENT

CRUSHER OPERATOR ing was required for the worker to learn operating Initially when all operations in the crushing system procedures and to acquire experience in adjusting and were combined and placed under the control of one performing operational maintenance on equipment. worker, the job was filled by CRUSHER MAN from KILN UTILITYMAN either the primary or secondary crusher. The workers selected for this job were from the The worker promoted to this job had 1 1/2years' MAINTENANCE-MECHANIC HELPER group experience in crushing system operations with at least who had from one to two years' experience in the nine months as an operator of either the primary or maintenance and repair department assisting others in secondary crusher. The worker was given three weeks the repair and overhaul of kiln equipment and auxil- of on-the-job training to learn the operation of the iary equipment, such as conveyors and material feed- new system. ers. Approximately two to three months of on-the-job training was required for the worker to learn operating CRUSHER OILER procedures and to acquire experience in the adjust- This job was filled from the MAINTENANCE- ment and operational repair requirements to become MECHANIC HELPER group by workers who indi- proficient. cated a preference for processing jobs. Approximately four to six months of on-the-job training was required LOADING AREA OPERATOR for the worker to learn the operation of the system BULK-CEMENT LOADERS were selected for and the adjustments required to keep the system in this job who had from one to one-and-a-half years' operation. experience related to bulk-loading and weighing operations with at least six months' experience as operator CENTRAL CONTROL OPERATOR of the bulk-loading and weighing equipment. The Former KILN BURNERS were selected to fill this workers selected were given two months' on-the-job job and were given specialized training. During the training on the new equipment and transfer system latter stages of the installation, and while the control during its installation and were proficient in its opera- system was being given preoperationaltests,the tion when it became operative. workers were given extensive and comprehensive LOADING AREA HELPER training in both operational procedures and actual operation of the system. The duration of the training No previous experience was required for this job. varied from six to nine weeks, depending on the Two weeks to one month was required for the worker learning ability of the worker. to become proficient. Workers in the LABORER classification were selected.

ASSIS PANT CENTRAL CONTROL OPERATOR COMPUTER MAINTENANCE MAN Former KILN BURNER HELPERS were selected Workers selected to fillthis job were recruited to fill this job. Requirements were that the worker from the journeyman ELECTRICIAN classification. must have experience in assisting others in controlling The workers were given extensive training on mainte- firing of the kilns, and that the worker must have nance and repair of the computer and electronic a good overall knowledge of all the production proc- theory by the computer manufacturer. The duration esses, and lastly, understand the functions and opera- of the course was approximately two months. On-the- tion of all the various production equipment. These job training was also provided during installation and workers were given two months' on-the-job training preoperative tests. by the CENTRAL-CONTROL OPERATOR under actual production conditions. ELECTRONIC MAINTENANCE MAN The workers selected to fill this job were recruited GRINDING UTILITYMAN from the journeyman ELECTRICIAN classification. The workers selected for this job were from the No formal training was given to these workers, but MAINTENANCE-MECHANIC group who had the manufacturer's representative gave informal in- from one to two years' experience in the maintenance struction to the workers on maintenance and repair and repair department assisting others in the repair and procedures for the various electronic systems as the overhaul of such equipment as material feeders, sepa- systems were installed. This instructioncontinued rator valves, air-slide equipment, and conveyors. Ap- until the workers could perform the required mainte- proximately two to three months of on-the-job train- nance and repair functionsproficiently. 13 .74

ARRANGEMENT AND CONTENT OF JOB DESCRIPTIONS The occupational descriptions are arranged alpha- fication of the aptitudes contained in the general apti- betically according to their titles. After the title, there tude test battery developed in the Bureau of Employ- appears first the code number which identifies the job ment Security. Those aptitudes were selected which within the classification structure of the Dictionary of seem to be significant in the job, and were identified Occupation Titles, third edition, published in 1965. in terms of specific work situations. The factor of Immediately following this code, there appears in intelligence, however, was not rated because of the parentheses a second code number. This is the occu- difficulty in writing meaningful descriptive statements pational code in the second edition of the Dictionary (ref. appendix). published in 1949. It is presented here only to save Interests:This component is defined as a preference time and minimize inconvenience in converting from for certain types of work activities or. experiences, the codes in the second edition to those contained in with accompanying rejection of contrary types of the third edition of the Dictionary. activities or experiences. Five pairs of interest factors The narrative portion of each job description is are provided so that a positive preference for one arranged as follows: factor of a pair also implies rejection of the other Job Definition.This provides a brief description of factor of that pair (ref. appendix). the duties involved in a particular job. It provides an Temperaments: The temperament component con- understanding of the tasks that are performed and the sists of 12 factors defined in terms of specific work skills and knowledges that are necessary to the per- situations that suggest different temperament-trait re- formance of these tasks, The job definitions will be quirements. Each work situation describes a type of essentially in the same form in a future release of the activity that demands a different adjustment on the Dictionary. part of the individual workers. Those temperament Education, Training, and Experience.This section factors were selected that appeared to be significant provides an indication of the amount of education and in the job, and were identified in terms of specific the level of training and experience usually required work duties (ref. appendix). for employment in the occupation. Physical Activities and Environmental Conditions: Special Characteristics.This section provides some These refer to (a) the physical activities required to estimate of the worker trait requirements pertinent to be met by the work, and (b) the working environ- ment which makes specific demands upon a worker's P. the specific jobs. physical capacities. There are six physical activities Aptitudes:These are the specific capacities or abili- factors and seven environmental conditions factors. ties required of an individual in order to facilitate the Those factors were selected that were significant in the learning of some task or job duty. This component is job in the sense that they met established criteria of made up of 11 specific aptitude factors, and is a modi- essentiality for successful performance (ref. appendix).

14 .71,

11110111140115.74

JOB DESCRIPTIONS AND WORKER REQUIREMENTS

ASSISTANT CENTRAL CONTROL OPERATOR CENTRAL CONTROL OPERATOR 579.782 579.782 (*6-67) (*6-67) Job Definition Job Definition Assists CENTRAL-CONTROL OPERATOR in Controls the operation of conveyor systems, feeders, controlling the operation of raw grinding mills, rotary raw grinding mills, rotarykilns, finish mills, and auxil- kilns, finish mills, and auxiliary equipment to produce iary equipment, from panelboard in central room to finished cement: Monitors area of panelboard desig- convey, grind, and blend raw materials, fuse raw nated by CENTRAL-CONTROL OPERATOR dur- materials into clinker, and to grind clinker into finished ing equipment startupor adjustment procedures. cement, following on-line processing computer data, Observes operating equipment for evidence of malfunc- and observing closed-circuit television and electronic tion and reports corrections, adjustments, or repairs and electrical recorders and indicators: Presses buttons needed to operator. Adjusts separator valves and air- and moves controls to start rock-storage conveyor slides as directed, using handtools. Occasionally re- system to convey crushed limestone, shale, and clay lieves CENTRAL-CONTROL OPERATOR during to storage bins, draw raw materials from storagebins brief absences from control room. for blending purposes, and to convey materials to raw mill-feet silos. Observes signal lights, level indicators, Education, Training, and Experience and weightometer reading to detect equipment mal- High school graduate is preferred. functions in system, determine bin levels, and to deter- Source of workers: Experienced kiln-burner helpers. mine rate of flow of materials, and adjusts controls, as Workers selected would be given two months' addi- required,toobtainspecifiedoperatingefficiency. tional on-the-job training. Such training is usually Presses buttons to start raw grinding mills and auxiliary given by experienced central control operators. equipment, such as conveyor system, and feeders, to proportion, blend, and grind raw materials. Presses SpecialCharacteristics buttons and switches to start rotary kilns and auxiliary Aptitudes: Verbal ability is required in understand- equipment, such as draft fans, kiln feeders, preheaters ing oral directions relating to operations given by and cooling systems in prescribed sequence to prepare CENTRAL-CONTROL OPERATOR and in com- for burning operations. Observes gages, indicators, and prehending written matter in operating and manufac- recorders on panelboard and inside of kilns through turing manuals. Clerical perception isrequired in closed-circuit television and adjusts kiln controls fol- monitoring panelboards. Form perception is required lowing data recorded on printout of online processing to detect equipment malfunctions. computer to \obtain highest quality clinker. Presses buttons and moves controls to start conveyor systems Interests: A preference for working with machines to convey clinker through coolers to storage silos, and and processes to continually operate and monitor the to draw clinker from storage silos and convey it to equipment that comprises the automated system. Inter- finish mills. Presses buttons to start finish mills. Turns est in activities of concrete and organized nature to controls to regulate rate of clinker f,-e,d into mill so consistently operate equipment according to specific that cement of specified fineness is obtained. Presses and detailed oral instructions. buttons and turns controls to control operation of dust Temperaments: Performs a variety of tasks requir- collector and separator systems and to reclaim salvage- ing frequent change to monitor equipment. Follows able materials. Presses buttons and turns controls to specific instructions to operate equipment. pump finished cement into storage silos. Notifies super- Physical Activities and Environmental Conditions: visory personnel when equipment requires major re- Work is sedentary and only occasionally is the worker pair work. Gives work direction to ASSISTANT required to exert physical strength in making adjust- CENTRAL-CONTROL OPERATOR in performing ments to such equipment as separator valves and air duties. slides. Reaching and handling of controls in control room is involved when making adjustments on operat- Education, Training, and Experience ing equipment. Near acuity of vision is required when High school graduation is usually required. monitoring sections of panelboards to read recording Source of workers: Experienced kiln-burners. Such and indicator. instruments. workers selected would receive two months' additional *MU' job is new to 1!..t.- economy. It did not exist in the time of the 2nd edition (and hence was not included in theDOT).

15 training by representatives of the manufacture of the resistors, and capacitors. Writes reports showing main- machine. Workers without this specific experience tenance work performed. Cleans accessible partsof would not be qualified for this occupation. computer daily with solvent.

Special Characteristics Education, Training, and Experience Aptitudes: Verbal ability is required to comprehend High school graduation is usually required. operating instructions from operation manuals and Source of workers: Journeyman electricians. Work- manufacturer's guides. Numerical ability- is required at ers selected would receive anadditional two months the level of arithmetic to prepare operating records. of on-the-job training given by representatives of the An understanding of data processing symbols is essen- manufacturer of the computer. tial to discuss operating difficulties with maintenance personnel. Clerical perception is required to adhere to Special Characteristics operating instructions. Manual and finger dexterity is Aptitudes:Verbal ability is required to compre- required to operate controls of panelboards. hend technical data from manufacturer's operating and repair manuals and confer with operating personnel Interests: A preference for working with machines regarding computer malfunctions. Numerical ability and processes to continuously operate and monitor the is required to prepare and solve formula requiring use equipment that comprises the automated system. In- of algebra and trigonometry. Spatial ability is required terest in activities of concrete and organized nature to to visualize circuitry of computerfrom schematics and operate equipment according to operating instructions diagrams. Form perception is required to recognize in manuals and manufacturer's guides. computer components in relationship toother com- Temperaments: Performs a variety of tasks subject puter components and to detectmalfunctions. Finger to change in the operation of panelboards. Adheres to and manual dexterity is required to use small tools and high level of accuracy to operate systems effectively. a variety of electrical andelectronic equipment in main- Applies specified predetermined actions in the event of taining computer in specified operation. Clerical per- equipment malfunctions. ception required to perceive print-out data. Color discrimination required to recognized color-coded wiring. Physical Activities and Environmental Conditions: Interest: Interest in scientific and technical subjects. Work is sedentary as physical effort is limited to push- Keeps abreast of development in field by reading tech- ing buttons and adjusting controls. Frequent walking nical journals concerned with the repair of electronic and standing is required in reading indicators and recorders in the various sections of the panelboards cov- equipment. ering three sides of the control room. Reaching and Temperaments: Performs a variety of tasks to diag- handling of controls is involved to start up, adjust, or nose equipment failureusing test equipment such as change operation of systems. Talking and listening is voltmeters, oscillators, and oscilloscopes. Makes de- involved in the direction of the ASSISTANT CEN- cisions concerning performance of equipment based TRAL-CONTROLOPERATORand other workers on reference manuals and tests.Works to precise and stationed at kiln and grinding stations. Near accuity established standards of accuracy following specifica- of vision is required to read instruments and recorders tions. while adjusting controls. Work is performed in an en- closed air-conditioned control room that is soundproof. Physical Activities and Environmental Conditions: Work islight, but involves frequent standing and COMPUTER MAINTENANCE MAN walking, and requires lifting of tools and equipment 828.281 weighing up to 15 pounds. Reaching and handling (5-83.444) involved in repairing computer or installing compo- Job Definition nents. Near visual acuity requiredwhen installing components and tracing out circuits, and inreading Inspects, tests, adjusts, and repairs electronic digital precision measuring instruments. Work is inside. computer and related electronic instrumentation used to control automated processes in manufacturing cement, following schematics, diagrams, andhandbook CRUSHER OILER instructions: Inspects computer and related instrumen- 570.885 tation to locate causes of malfunction. Solders faulty (*6-67) or loose connections, files contacts, oradjusts phasing, Job Definition using handtools and soldering iron. Tests suspected Performs the following duties involved in crushing circuits and components, using oscillators, signal gen- raw materials, such as limestone,clay, and shale, in an erators, oscilloscopes, and following schematicdia- automated cement plant: Starts crusher system equip- grams. Replaces defective parts, such astubes, coils, ment, such as secondary crushers, vibratory screens, * This job is new to the economy. It did not exist in the time of the 2ndedition (and hence was not included in the DOT).,

16 feeders, and conveyors, as directed by CRUSHER fled size for making cement: Presses buttons and OPERATOR. Observes operating equipment for in- switches to start, in prescribed sequence, such equip- dications of malfunctions and notifies CRUSHER ment as primary reducingmills and secondary reduc- OPERATOR of irregularities found. Adjusts equip- ing mills, vibratory screens, conveyor feeders, and ment as directed. Performs minor equipment repairs, conveyors. Signals workers to dumpmaterials into using handtools. Assists maintenance and repair per- crusher. Observes composition of material dumped into sonnel during major repairs of equipment. Greases crusher to detect variations in the amount of clay, conveyors, feeders, and other equipment of the crush- shale, or limestone and notifies supervisory personnel ing system using greasegun and fillsoil reservoirs. as required. Observes lights onpanelboard to insure Occasionally relieves CRUSHER OPERATOR for that equipment isoperating in prescribed manner. short periods. Clears chokeups in crusher with bar or directs operator of crane in clearing choketips. Inspects equipment at Education, Training, and Experience prescribed intervals to detect operating irregularities High school graduation is preferred. and notifies supervisory personnel when conditions Source of workers: Experienced maintenance help- require attention by other personnel. Directs other ers. Such workers selected would receive four to six workers inoiling and greasing equipment. Writes months' on-the-job training to learn the operation of daily report on tonnage of rock crushed. Occasion- the system. Generally, any worker having this type of ally operates overhead crane to clear chokeups. experience in the cement industry would qualify. Education, Training, and Experience Special Characteristics High school graduation is usually required. Aptitudes: Verbal ability is required to confer with Source of workers: Experienced primary or second- operating personnel regarding equipment startups and ary crusher operators. Workers selected would re- equipment malfunctions. Manual dexterity is required ceive additional on-the-job training of three weeks to in making minor repairs to equipment with handtools learn the operation of the system. Workers without and in starting equipment. this specific experience would not qualify.

Interests: A preference for working with machines SpecialCharacteristics and processes to continually maintain and adjust conveyors, feeders, and other parts of crushing system. Aptitudes: Verbal ability is required to comprehend Interest in activities of concrete and organized nature work orders regarding crushing operations, and in di- to maintain and repair equipment according to specific recting workers concerned with oiling and greasing instructions. equipment in crushing system. Manual and finger dexterity is required in adjusting controls and in clearing Temperaments: Performs a variety of tasks to repair chokeups in system with prybars. equipment and start equipment following specific instructions. Works to precise standards of repairing Interests: A preference for working with machines equipment indicated by repair manuals and instruc- and processes to continually operate and monitor tions. crushing equipment. Interest in activities of concrete and organized nature to consistently operate equip- Physical Activities and Environmental Conditions: Work is medium, involving almost continuous walk- ment according to established operatipg procedures. ing, standing, and lifting parts and tools weighing up Temperaments: Follows work orders and set pro- to 20 pounds. Worker is required to climb a ladder 125 feet to the top of the screening tower to inspect cedures to crush cement. Works to precise and estab- vibratory screens and feeders. Reaching and handling lished standards in operating crushing system to crush involved in adjusting equipment of system and in using rock to specified size. tools to make repairs. Working area is continually noisy due to vibratory screens and crushers operating. Physical Activities and Environmental Conditions: Dust continually in air from crushing and screening Work is sedentary. Some physical exertion is required operations. in clearing chokeups in system with prybar weighing about 15 pounds. Worker spends most of the time CRUSHER OPERATOR 570.885 either standing or walking. Reaches and handles con- (6-67.030) trols to adjust operation of system. Near acuity of Job Definition vision is required to read gages and indicators. 'Work Controls the operation of primary and secondary area is noisy fromequipment operating, making it crushers, and related auxiliary equipment from panel- difficult to conduct conversation in ordinary tones. board, to crush quarried limestone and shale to speci- Atmospheric conditions are dusty. ELECTRONICS MAINTENANCE MAN seven or eight feet and balances self when repairing 828.281 equipment. Reaching and handling of tools is involved (5-83.444) in maintenance and repair of electronic equipment and Job Definition instrumentation. Near visual acuity is required when Installs, calibrates, and maintains electronic equip- installing electronic components, tracing out electronic ment such as closed-circuit television systems, ampli- circuitry, and in reading precision measuring equip- fiers, level-indicator devices, and electronic instruments ment. Worker performs duties around operating used in controlling the manufacturing processes in a equipment where noise frequently exceeds 90 decibels. cement plant, following layout diagrams, schematics, Worker is subject to shocks when working on high and installation manuals: Installs and alines equipment, voltage equipment. such as cameras, transmitters, receivers, and amplifying and indicating devices' in various plant locations, such GRINDING UTil.ITYMAN as central control room, kilns, bins, and silos, using 921.883 signal generators, oscillators, and handtools, and apply- (7-88.210) ing knowledge of plant layout. Tests installed equip- JobDefinition ment and instruments, using oscilloscopes, tube testers, voltmeters, and analyzers, and makes adjustments as Maintains grinding machinery and auxiliary equip- necessary. Diagnoses malfunctioning equipment and ment in an automated cement manufacturing plant: repairs or replaces defective parts such as tubes, coils, Observes and inspects operating equipment such as condensers, and capacitors. Solders loose connections. feeders, conveyors, separators, and air slides for evi- Writes report showing maintenance work performed. dences of abnormal conditions such as lubrication leaks, material chokeups, material spills, and other failures. Education, Training, and Experience Repairs or replaces defective parts that can be made safely while equipment is operating, using handtools. High school graduation is required. Notifies supervisory personnel or CENTRAL-CON- Source of workers: Journeyman electricians. Work- TROL OPERATOR when equipment needs major ers selected would receive additional on-the-job train- repairs. Adjusts operating equipment, such as air slides, ing in maintaining the various electronic equipment in separator valves, and other flow apparatus as directed the plant until they become proficient. Generally, by CENTRAL-CONTROL OPERATOR. Greases other workers having experience in maintaining indus- equipment such as material feeders and conveyors, trial electronic equipment would qualify. and fills bearing reservoirs with oil. Unclogs chokeups Special Characteristics with bar and cleans up material spills with shovel. Assists maintenance and repair personnel during major Aptitudes: Verbal ability is required to comprehend repairs. technical data from manufacturer's operating and repair manuals. Numerical ability is required to prepare Education, Training, and Experience and solve formulas requiring use of algebra and trig- High school graduation is preferred. onometry. Spatial ability is required to visualize circuitry and components of the various equipment from Source of workers: Experienced maintenance help- blueprints and schematic diagrams. Form perception is ers. Such workers selected would receive two to three required to recognize equipment malfunctions. Finger months' on-the-job training to learn the maintenance and manual dexterity is required to use small tools and of the system. Generally, any workers having mainte- a variety of electrical equipment installations, nance experience in the cement industry would qualify.

Interests: Interest in scientific and technical subjects. SpecialCharacteristics Keeps abreast of development in field by reading technical journals and manufacturer's catalogs concerned Aptitudes: 'Verbal ability is required to confer with with the repair of electronic equipment. operating personnel regarding equipment malfunctions. Spatial ability is required to detect malfunctions in Temperaments: Performs a variety of tasks to diag- equipment. Manual and finger dexterity is required in nose equipment failures. Makes decisions in regard to using handtools to repair and adjust air slides, separator causes of malfunctions based on own knowledge, test valves, and other flow apparatus. data, and manuals. Must perform maintenance and re- pairstoexacting standards indicated by written Interests: A preference for working with machine specifications. and processes to continuously maintain and adjust Physical Activities and Environmental Conditions: grinding machinery and auxiliary equipment. Interest Work is light. Frequent standing and walking, and in activities of concrete and organized nature to main- lifting of tools and equipment weighing up to15 tain and repair equipment according to specific oral pounds are involved. Frequently climbs to heights of instructions.

18 Temperaments: Performs a variety of tasks to repair tivities of concrete and organized nature to maintain equipment, following work orders and oral instruc- and adjust equipment according to specific instructions. Works to precise standards of repairing equip- tions. ment indicated by repair manuals and instructions. Temperaments: Performs a variety of tasks to repair Physical Activities and Environmental Conditions: such equipment as feeders, coolers, and conveyors, fol- Work is medium. Constant walking throughout kiln lowing work orders and oral instructions. Works to area to observe and inspect the operation of equip- precise standards of accuracy indicated by repair ment is involved. Lifts and carries tools and parts manuals and instructions. weighing up to 25 pounds. Frequently climbs to various levels in the kiln area to inspect and repair Physical Activities and Environmental Conditions: equipment. Reaching and handling are required in Work is medium. Constant walking throughout the adjusting and repairing equipment. Work area is noisy grinding department to observe the operation of the due to machinery and equipment in operation. machinery and equipment is involved. Duties also require the worker to lift and carry tools and parts KILNUTILITYMAN4 weighing up to 25 pounds. Worker frequently climbs 921.883 to the various operating levels in the grinding depart- (7-88.210) ment to inspect and repair equipment. Reaching and Job Definition handling are required in adjusting and repairing equip- Maintains rotary kilns and auxiliary equipment in an ment. Working area is noisy due to machiner"- and automated cement manufacturing plant: Observes and equipment in operation. inspects the operation of kilns and equipment, such as kiln feeders, preheaters, clinker coolers, fans, feed LOADING AREA HELPER and clinker conveyors for evidences of abnormal con- 914.887 ditions, such as lubrication leaks, material chokeups, (8-67.01) and material spills. Feels bearings for evidence of over- Job Definition heating. Repairs or replaces defective parts that can Performs the following duties as directed by the be made safely while equipment is operating, using LOADINGAREA OPERATOR: Opens doors or handtools. Notifies CENTRAL CONTROL OPER- handhole plates on railroad cars or tank trucks and ATOR when major repairs are required. Unclogs inspects their interiors for cleanliness. Washes interiors chokeups with bar and cleans up material spills with with water when necessary. Spots railroad cars on shovel. Adjusts the operation of conveyor and feeders railroad scales using powered car mover or directs asdirected by CENTRALCONTROL OPERA- spotting of tank trucks on truck scales for bulk loading TOR. Greases conveyors, feeders, and other equip- of cement. Closes and fastens doors and handhole ment with greasegun and fills bearing reservoirs with plates and affixes seals to tank cars or railroad cars after oil. Assists maintenance and repair personnel during they have been loaded with cement. Sweeps loose major repairs of equipment and relining of kilns. cement from tops of cars and trucks. Cleans area around truck and railroad scales with power sweeper. Education, Training, and Experience High school graduation is preferred. Education, Training, and Experience Source of workers: Experienced maintenance help- High school graduate is preferred. ers. Such workers selected would receive two to three Source of workers: Generally, no experience re- months' on-the-job training to acquire experience quirements for entry into this occupation, but any maintaining kiln equipment. Generally, any worker experience in lower level jobs in the cement industry having maintenance experience in the cement industry is desirable. would qualify. Special Characteristics Special Characteristics Aptitudes: Manual dexterity is required in perform- Aptitudes: Verbal ability is required to confer with ing cleaning duties and spotting railroad cars. operating personnel regarding equipment malfunctions. Spatial ability is required to detect malfunctions in Interests: A preference for activities of a routine equipment. Manual and finger dexterity is required in concrete, organized nature to continuously perform using handtools to 'repair machinery and to adjust the duties involved in washing trucks and railroad separator valves or air-slide equipment. cars, spotting railroad cars, and cleaning work areas, according to specific instructions. Interests: A preference for working with machines and piocesses to continuously maintain and adjust Temperaments: Worker must adjust to a repetitive rotary kilns and auxiliary equipment. Interest in ac- work routine following specific oral instructions.

19 Physical Activities and Environmental Conditions: can be drawn from other silos.Prepares daily report Work is heavy, involving constant physical exertion of loadingactivities.Gives work instructions to due to the nature of the job. The worker is constantly LOADINGAREA HELPER. standing or walking, and lifting tools and materials weighing up to 20 pounds. The worker is frequently Education, Training, and Experience required to climb on and off railroad cars in perform- High school graduate is preferred. ing duties. Reaching and handling are involved in Source of workers: Experienced bulk-cement load- cleaning duties and in using power sweeper. ers. Workers selected would receive twomonths' on- the-job training to learn bulk loading and transfer LOADING AREA OPERATOR system. 914.885 (6-67.130) Special Characteristics Job Definition Controls the operation of weighing hoppers and Aptitudes: Verbal ability is required to understand feeder and conveyor systems from panelboard to oral and written instructions to perform duties. Cleri- weigh and load bulk cement into tank trucks orrail- cal perception is required in noting dray tickets and road cars, and transfer cement from storagesilos to bills of lading to load cement from specified bins. packinghouse silos, or to recirculate cement between Finger and manual dexterity is required to flip switches storage silos, following work orders:Reads dray ticket and move controls to perform loading operations. or bill of lading todetermine the type and tonnage of Interests: A preference for working with machines cement to be loaded. Signalsworkers to spot tank truck and processes to continuously weigh and load bulk on truck scale or to spotrailroad car on railroad scale. cement into railroad cars and trucks. Interest in activi- Moves control to lower loading spout into opening on ties of a concrete and organized nature to weigh and top of truck or railroad car. Sets selectorswitch to draw load cement following specific work orders. cement from specified bin and pushesbuttons to start feeder and conveyor system to load truck or railroad Temperaments: Follows written or oral instructions car with specified tonnage of cement.Stops equipment specifying type and tonnage of cement to load. 'Works when cement has been loaded and pushes buttons on to established standards of accuracy in loading cement. scale control panel to automatically weigh and record tonnage of cement loaded. Turns controls to start up Physical Activities and Environmental Conditions: feeder and conveyor systems to transfer cement from Work is light. Reaching and handling are involved in storage silos to packinghouse silos or to loadingbins or setting selector switches and moving controls to start to recirculate cement between storagesilos. Observes conveyor systems and feeders.Near visual acuity is level indicators and notifies supervisory personnel required in reading gages and indicators and setting when silos are running out of cement so that cement speeds of equipment. Work is performed inside.

";, SUMMARY hoists, Analysis of data obtained through researchand data materials handling equipment such as conveyors, collected during the study reveals thatmanufacturers and feeders. With the development of reliableelectronic and of cement, like those in so manyother industries, are control systems, In fact, it electrical instrumentation and remote automating their manufacturing processes. even more radicalchanges occurred. The on-station may be stated thatthe cement industry is going worker is no longer needed to operate ormonitor this through one of the greatest remodernization erasthat latest equipment. could be experienced by any industry. In automating its cement manufacturingplant, the Management of one of the companies stated,"When ABC Cement Company's goal was toachieve the in- one of the companiesin this area becomes fully auto- dustry's highest standards of quality.The greatest mated, all the rest of us must do likewise toremain in single element responsible for the companyreaching a competitiveposition." There are several reasons for that goal was the installation of anon-line digital com- this trend, but one of the most important isthe very puter to keep a watchful eye on everyfacet of the rigid standards established by the constructionindustry cement-making process. Many otherbenefits, in addi- and the government for the quality andcharacteristics tion to a far more rigid control onthe quality of of the cement the companies produce.Cement is being cement produced, werederived. Some of these benefits used more and more in the constructionindustry and were: Kilns wereoperated more efficiently; nonpro- more uses are beingdeveloped every year. Architec- ductive downtime for maintenanceand repair was 1,- tural designs using concrete that would havebeen fan- duced; costs of maintenance and repair werereduced; tasy in yesteryears are, infact, reality today. and average production was increased, Stringent quality control practices are not new to In comparing the staffing requirementsof the ABC the cement industry. The industry hasalways leaned plant with the conventional type cementplant staffing toward highly mechanized equipment for quality con- requirements, it is obvious that certainworkers are not trol purposes. When highly mechanizedequipment was necessary in acompletely automated cement plant. installed a few years ago, workers were requiredonly Available employment figures of the ABCplant indi- monitor this type of equipment. cate a decrease inemployment of about 13 percent. to manually operate or industry im- This type of equipment eliminated workersthat were Changeover to automated systems in this feeding materials into various equipment oroperating plies a definite reduction of on-stationworkers.

21 BIBLIOGRAPHY

Books Blanks, Robert F,, and Kennedy, Henry L.The Technology of Cement and Concrete. New York: Wiley, 1955. Witt, J. C.Portland Cement Technology. Brook ly:2, New York: Chemical Publishing Co., 1947.

Articles "Digital Computer to Automatic Cement Rock Crushing and Blending." Pit and Quarry, January 1959, pp. 138-139. Sauer, J. M., Weeks, L. W., Fleeman, P. J., and Kaiser, V. A."Riverside Puts Kilns Under Closed Loop Computer System." Pit and Quarry, July 1962, pp. 57-67. Utley, Harry F."Electronic Computer Controls Cement Production Variables." Pit and Quarry, March 1959.

. "Riverside's New Automatic Crushing, Storage and Blending Sys- tems." Pit and Quarry, July 1959.

Brochures Portland Cement Association.Cement and Concrete Reference Book.1939. Portland Cement Association.Cement and Concrete.1963.

22 INDEX OF OCCUPATIONAL TITLES

Page ASSISTANT CENTRAL-CONTROL OPERATOR 15 CENTRAL-CONTROL OPERATOR 15 COMPUTER-MAINTENANCE MAN 16 CRUSHER OILER 16 CRUSHER OPERATOR 17 ELECTRONICS MAINTENANCE MAN 18 GRINDING UTILITY MAN 18 KILN UTILITY MAN 19 LOADING-AREA HELPER 19 LOADING-AREA OPERATOR 20

23 APPENDIX

Worker Traits Aptitudes: 6. Motor Coordination.Ability to coordinate eyes, 1. Verbal.Ability to understand meanings of words and hands or fingers rapidly and accurately in making and ideas associated with them, and to use them effec- precise movements and with speed. Ability to make tively. To comprehend language, to understand rela- a movement-response accurately and quickly. tionships between words, and to understand meanings 7. Finger Dexterity.Ability to move the fingers of whole sentences and paragraphs. To present infor- and manipulate small objects with the fingers rapidly mation or ideas clearly-. or accurately. 2. Numerical.Ability to perform arithmetic op-, 8. Manual Dexterity.Ability to move the hands erations quickly and accurately. easily and skillfully; to work with the hands in placing 3. Spatial.Ability to comprehend forms in space and turning motions. and understand relationships of plane and solid objects. May be used in such tasks as blueprint reading and in 9. Eye-Hand-Foot Coordination.Ability to move solving geometry problems. Frequently described as the hand and foot coordinately with each other in the ability to "visualize" objects of two or three di- accordance with visual stimuli. mensions, or to think visually of geometric forms. 10. Color Discrimination.Ability to perceive or 4. Form Perception.Ability to perceive pertinent recognize similarities or differences in colors, or in detail in objects or in pictorial or graphic material. shades or other values of the same color. To identify To make visual comparisons and discriminations and a particular color, or to recognize harmonious or con- see slight differences in shapes and shadings of figures trastingcolor combinations,or tomatc13colors and widths and lengths of lines. accurately. 5. Clerical Perception.Ability to perceive pertinent 11. Intelligence.General learning ability. The abil- detail in verbal or tabular material. To observe differ- ity to "catch on" or understand instructions and under- ences in copy, to proofread words and numbers, and lying principles, Ability to reason and make judgments. to avoid perceptual errors in arithmetic computation. Closely related to doing well in school.

Interests: 1. Situations involving a preference for activities vs. 6. Situations involving a preference for activities dealing with things and objects. concerned with people and the communication of ideas. 2. Situations involving a preference for activities vs. 7. Situations involving a preference for activities of involving business contact with people. a scientific and technical nature. 3. Situations involving a preference for activities vs. 8. Situations involving a preference for activities of of a routine, concrete, organized nature. an abstract and creative nature. 4. Situations involving a preference for working for vs. 9. Situations involving a preference for activities people for their presumed good, as in the social welfare that are nonsocial in nature, and are carried on in rela- sense, or for dealing with people and language in social tion to processes, machines, and techniques. situations. 5. Situations involving a preference for activities vs.10. Situations involving a preference for activities resulting in prestige or the esteem of others. resulting in tangible productive satisfaction. Temperaments: The five degrees of physical activities factor No. 1 are as follows: 1. Situations involving a variety of duties often char- acterized by frequent change. (a) Sedentary WorkLifting 10 pounds maximum and occasionally lifting and/or carrying arti- 2. Situations involving repetitive or short-cycle op- cles, such as dockets, ledgers, and small tools. Al- erations carried out according to set procedures or though a sedentary job is definedas one which sequences. involves sitting, a certain amount of walking and 3. Situations involving doing things only under spe- standing is often necessary in carrying out job duties. cific instruction, allowing little or no room for inde- Jobs are rated sedentary if walking and standingare pendent action or judgment in working out job required only occasionally and all other sedentary problems. criteria are met. (b) Light WorkLifting 20 pounds maximum 4. Situations involving the direction, control, and with frequent lifting and/or carrying of objects planning of an entire activity or the activities of others. weighing up to 10 pounds. Also,even though the 5. Situations involving the necessity of dealing with weight lifted may be onlya negligible amount, a people in actual job duties beyond giving and receiving job is rated in this category (1) when it requires instructions. walking or standing to a significant degree;or (2) when it requires sitting most of the time but entails 6. Situations involving working alone and apart in pushing and pulling of arm and/or leg controls. physical isolation from others, although activity may (c) Medium workLifting 50 pounds maximum be integrated with that of others. with frequent lifting and/or carrying of objects 7. Situations involving influencing people in their weighing up to 20 pounds. Consideration (2) under opinions, attitudes, or judgments about ideasor things. light work may apply here. 8. Situations involving performing adequately under (d) Heavy WorkLifting 100 pounds maximum stress when confronted with the critical or unexpected with frequent lifting and/or carrying of objects or when taking risks. weighing up to 50 pounds. (e) Very Heavy Work--Lifting objects inexcess 9. Situatieris involving the evaluation (arriving at of J00 pounds with frequent lifting and/or carrying generalizations, judgments, or decisions) of informa- of objects weighing up to 50 poundsor more. tion against sensory or judgmental criteria. 0. Situations involving the evaluation (arriving at 2. Climbing and/or Balancing.These activities are generalizations, judgments, or decisions) of informa- defined as follows: tion against measurable or verifiable criteria. ClimbingAscending or descending ladders, stairs, X. Situations involving the interpretation of feel- scaffolding, rampsfpoles, ropes, and the like, using ings, ideas, or facts in terms of personal viewpoint. feet and legs and/or. hands and arms. BalancingMaintaining body equilibrium to prevent Y. Situations involving the precise attainment ofset falling when walking, standing, crouching, running limits, tolerances, or standards. on narrow, slippery, or erratically moving surfaces; or maintaining body equilibrium when performing Physical Activities Factors: gymnastic feats. 1. Lifting, Carrying, Pushing, and Pulling.These 3. Stooping, Kneeling, Crouching, and/or Crawling. are the primary "strength" physical requirements, and These activities are defined as: generally speaking a person who engages in one of StoopingBending the body downward and for- these activities can and does engage in all. Specifically, ward by bending the spine at the waist. each of these activities can be described as: KneelingBending the legs at the knees to come to LiftingRaising or lowering an object from one rest on the knee or knees. level to another; includes upward pulling. CrouchingBending the body downward and for- CarryingTransporting an object, usually hold- ward by bending the legs and spine. ing it in the hands or arms, or on the shoulder. CrawlingMoving about on the hands and knees or PushingExerting force upon an object so that hands and feet. The activities in this factor involve the object moves away from the force. This includes full use of the lower extremities as well as the back slapping, striking, kicking, and treadle actions. muscles. Therefore, stooping rarely is rated when PullingExerting force upon an object so that the the worker is performing this act while in a sitting object moves toward the force; includes jerking. position.

25 4. Reaching, Handling, Fingering, and/or Feeling. Accommodation is the adjustment of the lens of These activities involve the tise of one or both of the the eye to bring an object into sharp focus, This upper extremities and are defined as follows: item is especially important when doing near-point ReachingExtending the hands and arms in any work at varying distances from the eye. direction. Color vision is the ability to identify and distinguish HandlingSeizing, holding, grasping, turning, or colors. otherwise working with the hands or hand (fingering not involved). Environmental Condition Factors: FingeringPicking, pinching, or otherwise working 1. Work Location with the fingers primarily (rather than with the InsideProtection from weather conditions but not whole hand or arm as in handling). necessarily from temperature changes. FeelingPerceiving attributes of objects such as OutsideNo effective protection from weather. size, shape, temperature or texture by means of re- Inside is rated if the worker spends approximately ceptors in the skin, particularly those of the finger 75 percent or more of his time inside. Outside is to tips. be rated if the worker spends approximately 75 percent or more of his time outside. Those job-worker 5. Talking and/or Hearing.These activities are situations which may occur inside or outside are defined as follows: rated "B." Inside or outside should be interpreted as TalkingExpressing or exchanging ideas by means being synonymous with indoors or outdoors. of spoken words. 2. Extreme Cold With or Without Temperature HearingPerceiving the nature of sounds by the Changes.These conditions are defined as follows: ear. Extreme cold Temperature sufficiently low to The ability to talk is important for those job- cause marked bodily discomfort unless theworker worker situations in which the individual must im- is provided with exceptional protection. part oral information to clients or to thepublic, and in those situations in which he must convey detailed Temperature changesVariations in temperature or important spoken instructions toother employees which are sufficiently marked and abrupt to cause accurately, loudly, or quickly. marked bodily reactions. Hearing is important for those job-worker situa- 3. Extreme Heat With or Without Temperature tions which require the ability to receive detailed Changes.These conditions are defined as follows: information through oral communication, and to Extreme heat Temperature sufficiently high to make fine discriminations in sounds, such as making worker fine adjustments on running engines. cause marked bodily discomfort unless the is provided with exceptional protection. 6. Seeing.Seeing is the ability to perceive the na- Temperature changesVariations in temperature ture of objects through the eye. The moreimportant which are sufficiently marked and abrupt to cause aspects of vision are: (1) acuity, far or near; (2) depth marked bodily reactions. perception; (3) field of vision; (4) accommodation; and (5) color vision. These aspects of vision are de- 4. Wet and/or Humid. These conditions are defined as follows: fined as follows: Acuity, far is sharpness of vision at a distance of 20 WetContact with water or other liquids. feet or more. HumidAtmospheric condition with moisture content sufficiently high to cause marked bodily dis- Acuity, near is sharpness of vision at 20 inches or comfort. less. 5. Noise and/or Vibration.For this factor to be Depth perception is three-dimensional seeing and is rated, there must be sufficient noise either constant or an important factor in judging distances and space intermittent, to cause marked distraction or possible relationships so as to see objects where and as they injury to the sense of hearing and/or sufficient vibra- actually are. Two-eyed vision is involved here. tion (which is the production of an oscillating move- Field of vision is the area that can be seen up or ment or strain on the body or its extremities,from re- down or to the right or left while the eyes are fixed peated motion or shock) to cause bodily harm if on a given point. endured day after day.

26 6. Hazards.This category includes a variety of in- OdorsNoxious smells, either toxic or nontoxic. dustrial hazards, such as proximity to moving mechanical parts, electrical shock, working on scaffolding and Toxic conditionsExposure to toxic dust, fumes, high places, exposure to burns and radiant energy, and gases, vapors, mists, or liquids which cause general exposure to all types of explosives, all of which involve or localized disabling conditions as a result of inhala- the risk of bodily injury. tion or action on the skin. 7. Fumes, Odors, Toxic Conditions, Dust, and Poor DustAir filled with small particles of any kind, Ventilation.These conditions are grouped because such as textile dust, flour, wood, leather, feathers, they all effect the respiratory system or the skin and etc., and inorganic dust, including silica and asbes- are defined as follows: tos, which make the workplace unpleasant or are the source of occupational diseases. FumesSmoky or vaporous exhalations,usually odorous, thrown off as the result of combustion or Poor ventilationInsufficient movement of air caus- chemical reaction. ing a feeling of suffocation; or exposure to drafts.

printed itscALtronNtA°p.m!!Or STATZ PRINTING 70883-3505-66800