Document da8qbRqkN9ROnOgz3vqJ5ngg0

FILE NAME: Trade Publications (TR) DATE: 1932 Oct DOC#: TR023 DOCUMENT DESCRIPTION: Trade Journal Article - Dust Hazard in Rock Products Industry Recognized the World Over as the Leader in Its Field With which is Incorporated CEM ENT E W S Founded 1896 Entered as second-class matter, July 2, 1907, at the Chicago, 111., postoffice under the Act of March 3, 1879. Copyrighted, 1932, by Tradepress Publishing Corporation Contents fo r O ctober ,22 1932 A M odern M aterial H andling P lan t............................. 7-9 St. Louis Material and Supply Co. has new plant for the storage and delivery of sand. C em ent Industry in 1 9 3 1 ............................................ .38-39 Final government figures shoiu cement shipments were 0% less than in 1930. Opening a New Q u arry............. ..................................... 9 W ater C ontrol o f D ry M ixed C on crete....................... 42-43 The M an u factu re o f Portlan d C em ent................... ..10-11 P art V II--Properties of cement and effects of components ( continued). By S. E. Hutton. Crushed Stone Plant of M oderate Size with Un u su al F e a tu re s ...............................................................12-13 Cerulean Stone Co., Cerulean, K y., has dust collecting system and uses Diesel engine power. D ust H azard in Rock P rodu cts In du stry...................14-17 Only dusts containing silica are dangerous-- digest of papers and discussion at the National Safety Congress. Chemical A nalyses of the Particles of V arious Size s o f Ground C em ent.................................. 18-19 By E. T. Carlson and P. H . Bates. Hudson River Stone Corp. New Plant Inspected by C onstructors and E n gin eers................... 29 Cem ent M an u factu rers T a k e L ead in g 'P a rt in D rive fo r S a f e r H ighw ays......................................... 34-36 Will give society benefit of personnel made " safety conscious." Otho M. G raves Elected Chairman, Quarry Sec tion, N ational S a fe ty C ouncil................... 36-37 By G. W. Gleeson. Departments C h em ists' C orn er ................................................................18-19 H ints and H elps fo r Su perin ten den ts........................ 20-21 Rock P rod u cts C linic........................................................ 22-23 E d ito rial Com m ent ....................................................... 24-25 Fin an cial News and Com m ent................................. .26-27 Ed. Sh aw 's News L e tte r from Los A n g e les.............. 28 F oreign A b stra cts and Paten t R eview .......... ........ 30-31 Traffic and T ran sp o rtatio n .......................... 32-33 P ortlan d C em ent Production, Sep tem b er___ ___ .40-41 C em ent P rodu cts .................................................-- ....... 42-43 P rices o f M a te ria ls........................................ 44-47 New M achinery and Equipm en t.................................... 50-51 The In dustry ....................................................................... 54 C lassified D irectory of A d v e trise rs.............................56-57 (R o ck P roducts is indexed in the " In dustrial A rts In dex," which can be fou n d in any Public L ib rary ) TRADEPRESS PUBLISHING CORPORATION 542 South Dearborn Street, Chicago, Illinois, U. S. A. Nathan C. Rockwood, President; Fred S. Peters, Vice-President T. I. McKnight, Secretary I. H. Callender, Treasurer NATHAN C. ROCKWOOD, Editor and Manager EDMUND SHAW, Los Angeles, Calif., Contributing Editor EARL C. HARSH, WALTER B. LENHART, H. 0 . HAYES, Associate Editors A. M. STERN, Assistant Editor FRED S. PETERS, Advertising Manager JO S. J. KOLAR, Production Manager 'M BSCRIPTION--Two dollars a year to United States and Possessions. $4.25 a year to Canada (including duty) and $4.00 to foreign countries. Twenty-five cents for single copies E. H. PAULL, Eastern Representative 250 Fifth Ave., New York City. Tel. Ashland 4-4723 CEORGE M. EARNSHAW, Central Advertising Manager 522 Citizens Bldg., Cleveland, Ohio. Main 2559 L. C. THAON, Western Representative Chicago. Tel. Wabash 3714-3715 TO SU BSCRIBERS--Date on wrapper indicates issue with which your subscription expires. In writing, to have address changed, give old as well as new addles The A. B . P. is a nonprofit organization whose m em bers have p ledged them selves to a w orkin g co d e o f a p rac tic e in w hich the in terests o f the m en o f A m erican in d u stry , trad e a n d p r o f e s s io n s a r e p l a c e d f ir s t ----a c o d e d e m a n d in g u n b ia s e d e d i t o r i a l p a g e s , c la s s if ie d an d verified p a id su b sc rib e rs, an d honest ad v ertisin g o f d e p en d ab le p ro d u cts. The /.B .C . is an o rg a n isa tio n which a u d its an d verifies p u b lish e rs' circu latio n claim s an d record s. it <1 1 > I ht , ! 14 3Roo3k P ro d October 22, 1932 Dust Hazard in Rock Products Industry Only Dusts Containing Silica Are Dangerous--Digest of Papers and Discussion at the National Safety Congress TH E R E C E N T at Washington, National D. C., Safety Congress included a sym posium on the dust hazards to health in in dustry, a subject of particular interest to some rock products producers at this time because of the activity of a certain type of lawyer in promoting lawsuits for damages, running (in the aggregate) to millions of dollars. Dr. Leonard Greenburg, Yale Univer sity, New Haven, Conn., presided as chair man. The first paper by Dr. L. U. Gardner, director of Trudeau Laboratory, Saranac Lake, N. Y., dealt with the kinds of dust encountered in industry and their effect upon the lung tissues. The second paper by J . J. Bloomfield, U. S. Public Health Service, Washington, D. C., followed with a discus sion of the methods of determination of dust as to particle size and concentration in the air. The third paper by Dr. A. E. Russell, U. S. Public Health Service, Washington, D. C., discussed clinical and statistical studies in various dusty trades. In the fourth paper, Theodore Hatch, of the Harvard School of Public Health, Boston, Mass., discussed the various methods of dust control in industrial plants, and in the fifth paper, Prof. Philip Drinker, Harvard School of Public Health, outlined the various methods for protecting the worker against dust inhalation. Dr. L . U. Gardner said in p art: "'At first it was thought that all dusts were capa ble of producing disease, but with further study it became obvious that different types of dust produced different effects. With fur ther study it became obvious that dusts con taining silica were particularly harmful and that they produced definite changes in the lung tissues. Today we recognize silicosis as a form of disease which is quite definite. There are other forms of changes in the lung tissues which are produced by the in halation of dust about which we know little. "We know many of these dust conditions are associated with a factor of infection in the lung. Some believe that silicosis can not exist without a background of latent infec tion. However, this is an extreme view, as we know we can produce experimentally a true silicosis in animals by the inhalation of silica alone. 'Much has been written about coal miners and the factor of infection due to inhalation of dust. Pneumonia rates are excessive among coal miners, but probably the tuber culosis rate is lower than in other indus tries. This seems to end with different groups, and much more work must he done before we can talk definitely. Lime Dusts Not Injurious OCK PRODUCTS took an ac tive interest in the dust prob lem in its industries a s early as 1921, when the editor heard from various producers that lime and limestone dust had been regarded in the industry for generations not only as not harm ful, but actually helpful in the treatm ent of tuber culosis. In the January 14, 1922 issue is a 6-page article on " Lime and T aberculosis" containing a symposium o f the experience and opinions o f numerous lime manu facturers and a summary of exist ing literature on the subject. The subject has been continu ously discussed in Rock Products since that time. In the Jun e 28, 1924, issue is a 5-page article on the use o f both lime and gypsum dusts as possible preventives and cures for tuberculosis. These a r ticles received wide notice and Dr. Miriam Iszard w as led to make her thesis for her m edical degree at John s H opkins University on the subject. Her conclusions were not very specific as to the effect of these dusts as cures or preven tives, but Were qu ite definite that lime and gypsum dusts were not causes of tuberculosis, or silicosis, as are dusts containing silica. In the course o f these 10 years Roch Products collected and pub lished much inform ation in regard to experience and experim ents with lim e, lim estone and gypsum dusts which should be very help ful to any producer fa c e d with law suits as a result of alleged in ju ry to health due to exposure to these dusts. The great preponder ance o f evidence is that the " lime salt" dusts are dissolved in the lungs and provide calcareous m ate rial to heal the lesions o f tubercu losis.-- The Editor. " All dust, when inhaled, mechanically in jures the lung tissues, and the small par ticles injure the cells. We know that the type of injury varies with the nature of the dust particle." Dr. Gardner showed a number of lantern slides illustrating the effect of dust on the lung tissues: " If coal dust is present in ex cessive quantities and silica in relatively in significant amounts, we have a distribution which is comparable to that of pure coal. If silica is in excess and coal not abundant, we have a nodular type similar to silicosis "As far as asbestos is concerned, we do not know the whole story. \ n autopsy re port of an individual dying of asbestosis has shown a tuberculosis complication. Until we have more statistics of people working in asbestos dust we should not say too much about the part played by tuberculosis in asso ciation with this condition." A nalyses o f Mineral Industry Dusts J. J. Bloomfield said in part: During the past nine years he had made numerous investigations of the dust hazard in many industrial establishments. H e presented a summary which showed that the highest dust exposure was in talc mines, slate fin ishing mills, quartz (silica) grinding plants, coal mining and granite cutting operations. Owing to the high percentage of silica pres ent in the dust of quartz grinding and gramite cutting plants he found these to be the most hazardous of the occupations which he had studied. "A knowledge of the dust content of the industrial atmosphere is required," said Mr. Bloomfield, "not only for the purpose of de termining the extent of the hazard involved in various manufacturing processes, but it is also useful in measuring the efficiency of protective devices which may be used in the elimination of the dust hazard." In discussing the health hazard, he said : " It is now well established that the inhala tion of certain types of dust, such as granite dust, will in time produce fibrosis of the lungs, at times associated with tuberculosis. In other cases exposure to dust may result in the production of a far less degree of fibrosis without notable tendency toward subsequent tuberculosis; this is true of ce ment dust. And finally, there are certain types of dust as typified by marble dust, which in the quantities and lengths of ex posure so far observed produce little lung fibrosis. In general it has been found that those dusts which are high in silica content are the ones which produce a disabling fibrosis of the lungs most readily. Hence, the necessity for knowledge concerning the chemical and mineralogical composition of a dust is obvious. "With reference to the quantity of dust present in the air of a workroom, it is ap parent that when the dust concentration is high the exposed person will inhale a greater quantity in a given period of time than he will when the dust concentration of the at mosphere is relatively low, and since the rate of production of the disease is partially dependent upon the rate at which the dust is inhaled, this latter fact plays an impor tant role in predicting the relative danger of different environments. Hence the need for the evaluation of the quantity of dust in the industrial atmosphere is obvious " In general, it has been found that the harmfulness of a quartz-containing dust is in direct proportion to its quartz content. For this reason, in attempting to evaluate the harmfulness of a dust, it is of the utmost importance to ascertain its exact mineralogical composition. It has been our experience that to determine accurately the exact mineralogical composition of a dust one must resort to a combined chemical and petro graphic analysis. It is our practice to have such an analysis made by an expert in petro graphic geology." Dr, Bloomfield displayed a table which indicated the percentage of quartz content of dust obtained in the various industries which he had studied, as follows: Rock drilling dust (bituminous coal mine) ....................................................... 54.0% Granite cutting dust................................. 35.2% Rock drilling dust (anthracite coal mine) ..................................................... 31.0% Brass foundry dust....................................19.0% Dust from raw mills in cement plant. . . 6 5% Slate mill dust (Vermont red slate)... 3.0% Silverware polishing dust....................... 1.7% Anthracite coal dust................. 1.5% Bituminous coal dust............................... 1.2% Cement dust ............................................. 1.0% Slate mill dust (Vermont green slate)., trace Talc mill dust........................................... none Marble cutting dust................................. none " It is evident," said Dr. Bloomfield, "from this table that rock drilling occupations in the coal mining industry and certain occu pations in the granite cutting industry and in brass foundries would be in the hazardous class as judged by the proportions of quartz in the atmospheric dust." Silica Dust the "A rch Offender'' Dr. A. E . Russell said in p art: " The dust which produces the greatest damages are inorganic dusts, and silica is the arch offender. I have seen workers in dusty trades where silica is almost absent. E x posure to dusts will produce fibrosis of the lungs. A statement recently appeared in the `Cement Bulletin' that fibrosis in one case is not comparable to another. " I have visited marble workers. The men are apprenticed, going into the industry for a life work. I was anxious and very glad to see this group of workers. Dust counts revealed that marble workers are exposed to a smaller amount of dust than granite workers. We found that quite a number had more fibrosis than usual. Some had signs of tuberculosis. Dr. Rogers of Vermont State Sanitarium stated that he did not have marble workers as patients at his hospital unless they had previously worked in gran ite. We found no active cases of tubercu losis among this group in the marble in dustry. " Considering, silica, it has been my ex perience that one of the first and last com plaints is that it shortens the breath. A patient described it to me recently, saying that he had lost his second wind and did not have the usual reserve. Tuberculosis com plicates the cases in the various stages. A child can not live around an adult case with out being infected. They developed silicosis much more rapidly than those who did not have this infection " Silicosis is one of the foremost diseases. People all over the country are worked up over it. Many cases are coming before the juries. I believe in time they will have to subsidize hospitals in the larger cities and in most manufacturing cities. Diagnostic service should be provided. This proposition of submitting the evidence to lay juries is dangerous." Dr. Russell then presented several slides showing the results of coal, slate, marble, cement, asbestos and granite dusts on lung tissues. Physical Exam ination of Employes N ecessary Theodore Hatch said in p art: " The health hazard associated with exposure to industrial dusts varies with the industry and depends upon a number of factors, chief of which are the physical characteristics of those exposed, the chemical and physical properties of the dust, and its concentraton in the atmosphere of the work places. " The evaluation of the hazard in a given industrial plant must therefore be based upon a thorough investigation of the factory con ditions and a careful interpretation of the results. The investigation should include physical examinations of the men and a study of morbidity and mortality statistics, chemical examination of the dust, and deter minations of its physical properties such as particle size. "The most direct means of controlling the hazard is by reducing the dust concentration to which the workers are exposed. The efficiency of the required dust control de pends upon the allowable concentration in the atmosphere, which in turn is determined by the toxicity of the dust and the tolerance of those exposed. The standard of permis sible dustiness may be increased by careful selection of the men, by means of physical examination, and limiting their exposures through a system of rotation of employment. It may be further increased by reducing the percentage of toxic material in the dust and otherwise controlling its chemical and physi cal characteristics. " In the absence of definite knowledge, the safe course is to consider all dusts dangerous until proved innocent. "The dusty processes encountered in in dustry differ widely and exhibit a consider able variation in the restrictions placed upon the design and operation of the devices for the control of the dust. No single method of control can be universally applied; on the contrary a number of methods have been developed to meet the needs of the dusty trades and the choice of method must be based upon a thorough study of local con ditions. The common methods follow : "Substitution of .Von-hazardous Processes'. The silicosis hazard has been reduced in a number of industries by substituting for the dusty process one which is dust-1 ice or which produces a relatively haimlesa (hot In the granite industry the surfacing ma chine, a heavy dust producing tool, has In-on replaced to some extent by the gang and the artificial abrasive wheel. These are wet processes and have reduced the dust concentration associated with the surfanng of the stone to a figure well below the hygienic face limit. Control of Dusty Operations " Isolation of the Hazardous Process It is possible to isolate the dusty process m many cases. This may consist merely m confining the hazardous stages of manufac ture to a separate building or room, the-ehj reducing the number of men exposed to t ie dust (and these men may be protected by m asks), or it may mean complete isolation from the workers in an enclosed space. " General Ventilation: In a few instances of generalized dust production throughout the factory the use of general ventilation may prove satisfactory as a means of dust control. Under such conditions the in troduction of large quantities of dust-free air serves to reduce the dust concentration by simple dilution. This method is used in certain mining operations, also for purposes of removing heat and toxic gases as wed as dust. In general it involves the installation of large fans and is expensive to operate This method should be looked upon as an adjunct to other methods of control rather than an independent method. " Control of Dusts at the Origin: Effec tive control of the dust at the point of gen eration prevents it from reaching the breath ing zone of the worker and hence offers a positive means of reducing the dust hazaid. It may be effected by the use of water or other liquids for capturing the dust or by means of local exhaust ventilation. The use of water for laying dust is an old method of control. It undoubtedly reduces the dust concentration, but investigations have shown that it does not always give the high degree of protection required. Local exhaust ven tilation consists in removing the dust through a suction hood placed close to the point of generation. This method of control is widely used in industry and is most effective when applied to a stationary dust-producing ma chine or when it is attached to a moving tool, thus keeping it at a fixed distance from the point of dust origin. Its general appli cation has been recognized and most states have incorporated specifications for the de sign of local exhaust systems in their in dustrial code." P rotective D evices fo r W orkers Prof. Philip Drinker said in part: " Pain ful as the cure may be, it consists of two perfectly definite steps: (1) Medical examina tions of new employes and routine examina tions of all persons exposed to dangerous dust concentrations; and (2) reduction of dust concentrations breathed by worker:- to what are considered to be safe limits. 16 October 22, 1932 `'If dustiness can be controlled by local exhaust fans and dust-collecting equipment, protective devices such as respirators or positive pressure helmets have no place ex cept as emergency equipment. However, many processes like abrasive (sand or steel) blasting, paint and enamel spraying, porce lain manufacture, stone cutting, sand grind ing, and the like, will not, in all probability, be made reasonably dust free for some years to come In work of this type, respirators and other protective devices have an impor tant place. The safety man should under stand thoroughly what can be expected of protective devices and, above all, should be able to check and observe whether the work men are getting the protection they require. "One sees occasionally statements to the effect that respirators have no place in in dustry because they filter out only large particles and let pass the small ones which are always the more harmful. Against this is the indisputable fact that the dust catching efficiency of several makes of respirators exceeds 90% on silica dust with particles less than two microns A careful measure ment of the size of dust particles entering and leaving respirators shows a slight but unimportant reduction m average size of the dust particles." Professor Drinker reviewed the specifica tions for respirators which have been for mulated by the U. S. Bureau of Alines and paid glowing tribute to the high caliber of its work and its importance to the safety movement. Also he outlined the require ments for testing sand blast helmets and paint spray masks. "The manufacture of protective equip ment," he said, " should be allowed all pos sible license in modifications and improve ments having to do with appearance, ob struction to vision, comfort, ruggedness and practicability of his equipment. If the manu facturer desires his product to be certified as to its performance under the conditions for which he designed and built it, the pro spective purchaser and safety engineer is equally desirous of knowing the performance data." D iscu ssio n Discussion was withheld until all papers were read. Chairman Greenburg then called upon various people for comment. Follow ing this the meeting was thrown open for general discussion and then the original speakers called on for replies, Dr. Pancoast, pathologist, University of Pennsylvania, said in part- "I have been interested in silicosis for a number of years. We have the tery best wav of finding out what changes are taking place in the lungs by x-rays. There can be no dispute to that question. We also have one of the best ways of determining the incapacity of the individual, but most of these examinations are not carried out thoroughly and the in formation is not given. The x-ray exam ination is only one small part, and that is something that is overlooked so frequently. A physician who has little knowledge of the subject will present x-ray pictures--and diagnose silicosis as the cause! It takes all of the ability of many witnesses who know something about the subject to counteract the few words he may say. Many here know that. We must know the kind of dust, dust counts, chemical constituents of the dust, clinical aspect of the case, time of work, how long he works each day, whether he is breathing the general atmosphere of the room or a more concentrated atmosphere. Previous occupation is often overlooked. All of these different sides to the question must be taken into consideration m every instance in which a man is charged with lack of capacity for work." Dr. McConnell, M etropolitan Life In surance Co., said: " Dr. Russell made a very important point in calling our atten tion to the necessity of having authority to decide cases. This is a matter of consider able interest to the meeting, and much thought should be given to it." Mr. Cunningham said: " The whole sit uation lias been presented very thoroughly. Two things have occurred to me: (1) Those stone cutters who have cut limestone for 15 or 20 years and who have tubercu losis, in eacli case have cut sandstone previ ously. Whether a short exposure a long time ago is important 20 years later is im portant. (2) Examination of workers who have been exposed simultaneously to silica and alkali. Reports have been made show ing silicosis may develop rapidly. 1 am in terested in the presentation of the situation regarding the control of dust because it is the real problem ahead oi us." Dr. Lloyd, (J. S. Bureau of Standards, sa id : " Dr. Drinker fold us how they test the respirator and pointed out the impracti cability of using positive air pressure as a dust eliminator. A definite opinion is de sired as to what type of respirator is ade quate under bad dust conditions and within acceptable operating limits for protecting a man." Dr. Drinker: "I certainly do not con sider respirators adequate under such cir cumstances. Supposing you have a dusty atmosphere of, say, 50,000,000 count and you want to reduce it to 20,000,000. If your respirator is 90% efficient it would get the dust concentration down to 5,000,000, but eight hours a day constant use will be ob jectionable. In jobs in places like foundries, mines, sand blasts, etc., the exposure is not continuous. In such cases the respirator is not worn continuously-." Dr. Knutsen, W isconsin Industrial Com mission. said: "Tw o or three of the speak ers made mention of the decision of claims which are made as the result of men be coming incapacitated in working in (lusty occupations. "This, to me, has been one of the most interesting sections I have attended in over 10 years of Safety Council meetings. The problem of silicosis and tuberculosis has been before us in Wisconsin since 1917, because of the fact that at that time our compensa tion law was amended providing compensa tion benefits for any disease or disability resulting from an occupation. I appreciate that one or two states have such provisions. I suggest one way of deciding a case is to have compensation laws amended covering all diseases of occupations so that claims may be decided by the industrial commission rather than by juries as the result of civil claims being filed. "I will relate briefly difficulties we have. I do not wish to make a statement reflecting on the medical profession. The difficulty is th is: Oftentimes a claim is presented to us for compensation by some individual because of a disability allegedly resulting from sili cosis. In many of those cases we have mem bers of the medical profession testify in behalf of the clients, who we personally are satisfied are not specialists or competent along those particular lines. The discourag ing thing to us is that in hearing the evi dence we have men before us who have specialized for years in lung diseases, men who are engaged in private practice and are at the head of tubercular institutions, testify ing one group on one side, that the results of physical findings and x-rays show that the patient is disabled as a result of silicosis. Others equally qualified testify to the con trary. We have had some of these cases when we heard testimony and the individual didn't have long to live. We withheld our decision until the individual passed away and suggested an autopsy. We can not force an autopsy, but we are privileged to withhold our decision. After the autopsy, these two groups of doctors take specimens, examining them microscopically, and we hear them tak ing the same position that they had in the first hearing. That, I want to say, is mighty discouraging." Dr. Roach, compensation commissioner for the state of New Jersey, said in part: "I am very much interested in the subject, because silicosis is a thing that we are veryr much concerned about in New Jersey at the present time. I might say that vve have some experience in compensation cases in the state parallel to that described by Com missioner Knutsen from Wisconsin. It doesn't require much evidence to prove that certain quantities of silica are harmful to the human system. After an exposure continu ous over a period of time long enough, per manent physical damage is hound to result, maybe to the point of the extinction of the individual. There are certain things that I am very much concerned about m connection with this subject of dust To find some workable productive device that will safe guard the men who are exposed in 60 or 70 different industries to silica dust. It is not easy. It nun be that in the laboratory ex- periment-, under rather favorable conditions, a piece of apparatus may be developed which is satisfactory Respiratory devices that might be good on some may not work so well on others." Dr. J. G. Cunningham, com m issioner of hygiene, Toronto, Out., said in p art: "Many cases in mining come from physicians when examining miners for employment. All cases are referred to a compensation board. When the claim is received by the board it makes its arrangements to insure that all other re quirements of the act have been met. In Ontario a miner must be exposed for five years. Other occupations have various ex posure time limits. After these provisions have been met the cases are referred to a referee board, which is composed of three members, two of whom must see the case and complete the examination. Decision must be unanimous, and is final, and the claim is referred back to the compensation board." Dr. Russell: " Dr. Cunningham spoke of finding among his limestone workers that they had worked in sandstone years before. If you will remember in the `Granite-Cutting Bulletin' the death rate for manufacturers was almost equal to that of granite cutters. In most instances he (the manufacturer) was not exposed to dust. He did not work at it eight hours a day. The story is that the majority of manufacturers started out and learned the stone business by being granite cutters. " In these days of law suits it is surprising how quickly experts can develop. I think commissioners and their boards should pay more attention to the qualifications of their experts." Dr. Sayers, U. S. Public Health Service, said in p a r t: " I have in mind two cases. The men both had silicosis and tuberculosis for 19 years. Both of them are still at work We have examined them periodically right along during the period. They are not in good condition, but they are at work. I do not believe we are in a position to say whether a man has susceptibility to tuber culosis. Throughout the time the informa tion was available, it looks as though suscep tibility to tuberculosis continues for at least 20 years." Dr. Lawrence Greenburg: "Will some one say something regarding the so-called acute cases of exposure? Most of us have the idea it is a matter of long gradual ex posure." Dr. Russell: "A cute silicosis is a prob lem that is facing industry'. I personally can not think of silicosis as anything but chronic, my first experience being with granite work ers. One case of silicosis had eight months' exposure. In a tuberculosis sanitarium the superintendent was kind enough to give me an x-ray. It is sometimes impossible to demonstrate physically or with laboratory evidence a case of active tuberculosis. In The Journal of the American Mdirai A sso ciation, an article by Dr. Chapman of Boston tells of exposure extended to three year-. They were considered as acute cases." Management of Labor in Mining Operations I TOW some of the mining companies ha\e ^ ^ developed efficient organizations is d e scribed in Information Circular 6050. "M an agement of Labor in Successful Metal Mine Operations," recently published by the U. S. Bureau of Mines. This 35-page bulletin summarizes the data contained in some 80 information circulars on individual mines and discusses the advan tages and disadvantages of various systems of paying and handling labor. Since the cost of labor is more than 60(/< of the cost of mining, the development of efficient, willing workers is of the greatest importance Organization, responsibility and planning are also discussed. According to the circular, 40% of the mines described operate entirely on a contract or bonus sys tem, 44% operate partly on contract or bonus and partly on a day wage basis, and 16% operate on a day wage basis. Increasing Cement Kiln Output * I 'H E use of chains in the feed end of a wet process cement kiln is described in an article by E. Schirm in the September issue of Cement and Cement Manufacture. The first of.the accompanying illustrations shows an arrangement of chains to effect heat transfer and to expedite the passage of F ig. 1. A rran gem en t o f long' ch ains the material along the kiln. The chains are attached in groups (three groups only being shown in the illustration) in a spiral forma tion, ihe curtain of hanging chains forming a spiral surface which moves the material forward as the kiln revolves. This arrange ment gives a good exchange of heat between the gases and the material. The second illustration shows another ar rangement where short hea\y chain- a e used. They are hung in spiral formation -u that they may move the material along t ie kiln more effectie ely. but the greater .art of the kiln section is left open so that t icie is not as much transfer of heat H m u u r , Fig. 2. Arrangement of short chains it is stated, t'le lung light chains can be used along with the short heavy chains, or each kind can he used in alternate zones. The article states that the use of chan s and other devices in the upper zones has considerably increased the output and tint it has been found that the clinkering /one can readily handle more than the normal quantity of material which would pa-s through a plain kiln. It is also stated that the radiation lo-s from a kiln depends upon the shell dime isions rather than the amount of material passing through and that the loss per nmt of output is reduced by working at higucr capacity. These methods in the wet process and similar methods in the dry process are stated to be an important advance in that one kiln can he made to do the work of tvw Rubber Sheathed Cables A C C O R D IX G to the Bureau of Mine'* * thereriias been a marked improienh'in in recent years in the construction and p.-r formance of rubber sheathed trailing cabU used with electrical equipment. While some failures are due to kinking and overheat im. when on a reel, most are caused by crushing as a result oi being run o\er by a ear or being struck by falling material. Crushing tests made by the bureau, using a 7-ton car, indicate that twin or duplex-type cables withstand sucli crushing better than concen tric types. Full information covering these investig..tions is contained m a 52-page booklet pub lished by the Bureau of Mines, U. S. 1>cpartment of Commerce, as Bulletin 3s,X. which may be obtained from the Supeni tendent of Document.-, Washington, D. C Canada Asbestos Production A S B E S T O S production in Canada dm ^ ^ ing July amounted to 7171 toils, a d i cline of 10.1% from the June shipments ami 47.3% from the July, 1931, total. During the seven months ending July. Canadian pro ducers shipped 60,753 tons as compared w th 93,386 tons ir the corresponding pel md <i 1931. K .ailFS2it; October 22, 1932 Announcing The 44WDW Well Drill Sharpener The "WD" Sharpener has behind it Ingersoll-Rand's twenty years of ex perience in building drill steel sharp eners. In addition, it has two years of successful field operation actually sharpening well drill bits before it was offered to the trade. C lam p in g Dollying Swaging G au gin g 100 per cent ream ing edge T ru e enttinii edte One quarry reports the "WD" Sharpener has cut their drilling costs 61 per cent. Two other quarries report cuts of 50 per cent in drilling costs. All three quarries report a saving of 50 per cent in sharpening costs. O ur nearest branch will be glad to give you fu rth er inform ation. Ingercoll-Rand <|f 1 1 Broadway, New York City J8M!S8 Steam Turbines, for all speed and steam conditions; capacities up to 15,000 hp. C atalog D149. Helical G ears. C atalog R149. Centrifugal Pum ps, lor all capac ities. Catalog B149. Centrifugal Blow ers and Com pres so rs. C atalog F14. Worm Reduction G ears. C atalog R149. Flexible Couplings. C atalog K149. W ater W heels. C atalog T149. A L L E N Cones and Tanks For Wet Grading of Sands Will economically produce clean, accurately graded sands, and enable you to meet sand requirements of the most rigid specifications. Write fo r details. Allen Cone and Machinery Corporation 30 Church St. E N G IN E E R S New York, N. Y. Complete Quarry and Gravel Plant E Q U I P M E N T From Crushers to Bin Gates Write today for Bulletin 266 Smith Engineering Works, 5 0 8 E. C ap ito l Drive, M ilw aukee, Wis. TELSMITH Ti m i PERFORATED SCREEN SECTIONS AND PLATES The name C R O SS represents a standard of quality in perforated metals. Always glad to quote prices on round, square, slots or any design perforat:on punched from special or ordinary steels for revolving, vibrat ing and shaking equipment. Perforators-- Fabricators-- Machminuists 4 CROSS ENGINEERING COMPANY M anufacturing P lan t and G eneral Offices CARBONDALE, PA. pL lM U sA riO N ol "^stuffing box haa done a w a y wi t h many troubles common to cen trif ugal pumps. Pump m a i n t a i n s extraordinary effi ciency. W earing p arts un usually heavy, in s u r i n g long life. Cleaning out pump or changing w ear ing p a rts requires only a few m in utes. D escribed and illu strated in our new C atalo g No. 8 A. R. Wilfley & Sons, Inc., Denver, Colo., U. S. A. October 22, 1932 THE MERRICK CONVEYOR WEIGHTOMETER A ny m aterial which is con veyor-handled can be weighed without additional handling or loss of time by the Merrick Conveyor Weightometer. An Autom atic-- Continuous-- Accurate Record MERRICK SCALE MFG. COMPANY Passaic, N. J. SCHAFFER ELECTRIC VIBRATOR KEEP YOUR FINE M A T E R I A L S IN STORAGE BINS FREE FLOWING BY INSTALLING SCHAFFER ELECTRIC BUN VIBRATORS PROPORTION BY WEIGHT If you have a mixing prob' em you would like to handle autom atically and accurately it will pay you to investigate S C H A F F E R PO IDOM ETERS. W rite fo r B u lletin A SCHAFFER POIDOMETER CO. Pittsburgh, Pa. 61 The severest duty to which you can put any air hose is taken as part of the day's routine by Goodyear Emerald Cord Air Hose. It withstands the pulsating pressure, withstands vibration, and stands up ruggedly under abra sion and wear. Its central tube is specially compounded to resist the action of both warm and cold lubricating oils. Its body of double-braided stoutest Goodyear Cord withstands pressures from within and with out, and also resists vibration. Its firm, tough cover is staunchly resistant to the abrasion encountered on sharp rock and rough surfaces. Goodyear Emerald Cord Air Hose, Style M, and Wingfoot are specified to your particular service by the G.T. M.-- Goodyear Technical Man. You will find you get more efficient hose, and also save considerable money in hose replacements, if you have the G .T . M. handle your hose re quirements. To get in touch with him, write to Goodyear, Akron, Ohio, or Los Angeles, California, or call your nearest Goodyear Mechanical Rubber Goods Distributor. All Goodyear products are constantly under develop ment and test fo r furth er improvement. Each new advance is completely mill- or mine-proved when offered for industrial service. BELTS October 22, 1932 MOLDED GOODS HOSE PACKING 55 Do You Know Your Drying Costs? First cost, reduced to interest and deprecia tion at 16% per year is usually 15% of the operating cost. Therefore, 85% of your thought should be given to operating costs. Do you know yours? Ruggles-Coles Dryers are unquestionably the most economical and the most efficient on the market. Where else can you dry Clay from 23% to 2% mois ture for $0,351 per ton? Or Sand from 6% to 0 for $0,105 per ton? Or Coal from 9% to 1% for $0,172 per ton? Write for facts on Ruggles-Coles installations Hardinge Company, Inc. York, Pa. New York--122 East 42nd Street Chicago-- 205 West Wacker Drive San Francisco--235 Montgomery St. INDEX TO ADVERTISEMENTS A Allen Cone & Machineiv Corp. . .. 61 American Steel Sc Wire C o .................... 3 B Babcock & Wilcox Co................... 6 Bradley Pulverizer Co................................. 59 Brodgrick & Bascom Rope Co................... 58 Bucyrus-Erie Co. 5 C Chicago Blow Pipe Co. . . .. 60 Chicago Perforating Co............................... 62 Clark Dust Collecting 'Co. ........ 60 Classified Advertisements ...................... 62-63 Classified Directory of Adveitisers........56-57 Cleveland Wire Cloth & Mfg. C o........ 60 Cross Engineering Co. .............................. 61 D De Laval Steam Tmhine Co . . 61 E Easton Car & Construction Co. . 62 Ensign Bickford Co............. .......... 62 Ai F Fail banks, Morse & Co............. 1 Fate-Root-Heath Co............................... 61 Frog, Switch & Mfg. Co............................. 62 Fuller Co........................................................ 62 G GoocKear Tue & Rubber Co., Inc. . H Hardinge Company ................................... 64 Harmschfeger Corp...................................... 58 Harrington & King Perforating Co....... 59 Hayward Company ................................... 59 Hazard Wire Rope Co.............................. 53 Hendrick -Mfg. Co..................................... "8 I TngersoII-Kand Co.......... Inside Fiont Co\e> L Luonus Machine Co.............. .. 62 M McLanahan & Stone Corp................ 60 Metrick .Scale Mfg. Co.............................61 N Moidberg Mfg. Co ........ Inside Back Cover P Pennsylvania Ci usher Co........................... 60 Plymouth Locomotive Works................... 61 R Ruggles-Coles Eng. I)iv. of the Hard inge Co., Inc........................................... 64 Ryerson, Jos. T., & Sons, Inc................. 60 S Schaffer Poidometer Co............................. 61 Smidth, F. L ., & Co................................... 4 Smith Engineering Work1 ................... 61 U Universal Vibrating Screen Co................ 60 Used Equipment ...................................62-63 W Welch, F. M., Eng. Service, Inc............. 7 Wiifley, A. R., & Sons, Inc.................... 61 Rock Producta