Search Documents

By Graham W. Marks, RALPH MILLS, FRANK COSSEY

To determine the focal length of lenses or the performance of lens systems before mounting them permanently , it is desirable to have a device in which one or more lenses can be mounted easily and their positions relative to a light source and screen changed readily . We have designed and constructed such an optical bench and lens holder . The bench is similar to that of Houstoun5/ but has been modified , whereas the lens holder is , we believe , a new design .

Jan 1, 1948

By A. U. Miller

For many years Illinois has been one of the leading coal producers in the United States and as such its safety record has compared very well with the other large coal producing States , both in tons produced and millions of man -hours of exposure per fatal accident . ( See Table 25 in Bureau of Mines Bulletin 293. ) During the 10-year period from 1917 to 1926 , inclusive , the average production in the United States per fatal accident was 278 , 109 tons . The aver age for the State of Illinois for the same period was 409,249 tons . Illinois produced 450,464 tons per fatal accident, and in 1928 produced 390,630, tons , or an average of 419,721 tons for the 12- year period from 1917 to 1928 , inclusive . In 1927 During the year 1929 , the shipping mines of the State made a decided improvement in their record over any previous year . Table 1 shows the monthly production and the tons produced per fatal accident . During 1928 and 1929 safety work was actively carried on in Illinois . Safety meetings were held with mine officials , representatives of the State. De partment of Mines , and the United States Bureau of Mines . At these meetings mine hazards and accidents were discussed and remedies suggested for : their elimination in the future . It is believed that first - aid training was to a considerable extent instrumental in reducing accidents and in making the good safety records in Illinois during 1928 and 1929. During these years ( as well as in 1926 and 1927 to a somewhat less extont ) en intensive rirst-aid training campaign was con ducted in Illinois by the officials and members of the United Mine Workers of America , coal companies, State Department of Mines and Minerals , and the U. S. Bureau of Mines , Every first -aid class was made a safety meeting ; where accidents and general safety were discussed freely while teaching first aid. During this time , anproximately 25,000 persons were trained in first aid, and 17 coal companies were issued certificates for having 100 per cent of their employees. trained in first aid. Since January 1 , 1926 , more than 40,000 have received first -aid training in and around Illinois mines , and including those who received training previous to this date , it is believed that at least 90 per cent of the miners in Illinois have received first -aid training . This state ment is based on the fact that the labor turnover in Illinois is not large .

Apr 1, 1931

By G. W. Jones, R. E. Kennedy

Most gasolines and naphthas are mixtures of paraffin- series hydrocarbons and comprise such substances as pentane , hexane , heptane , octane , and others up to perhaps dodecane . Many of these hydrocarbons , when mixed with the proper proportions of air and ignited , are highly explosive . It is due to this characteristic that gasoline has become so important as a fuel in internal -combustion engines . Gasoline and naphtha also are used in the industry as solvents and cleaning agents . Because of their explosive properties they are dangerous to use unless the composition is so chosen that the vapor pressure of the mixture is not high enough to produce explosive mixtures with air at the temperature at which they are used . Hydrocarbon mixtures may be made less hazardous by adding some incombustible liquid , such as carbon tetrachloride . Barrier reports the amount of carbon tetrachloride that must be added to different naphthas to render such mixtures free from fire and explosion hazards . He found that the amount of carbon tetrachloride that must be present in the final mixture of naphtha and carbon tetrachloride varied with the density of the naphtha . Of the naphthas tested the amount of carbon tetrachloride necessary to render such mixtures free from fire and explosion hazards ranged from 30 to 70 percent . .. Determination of the fire and explosion hazards of carbon tetrachloridehydrocarbon mixtures would be easy if the boiling points and vapor pressures of the two were the same at any given temperature . The fact that carbon tetrachloride boils at 76° C. while the boiling points of the hydrocarbons found in gasoline and naphtha may range from 37° , the boiling point of pentane ,

Nov 1, 1934

By Will H. Coghill, Fred D. DeVaney, R. S. Dean

Part I CONTENTS

May 1, 1934

By McHenry Mosier

The application of diamond drills for blast holes is limited to the special Job of extracting floor and stope pillars, and therefore their operation is intermittent. The zinc ore drilled occurs in metamorphosed dolomitic limestone. The mining method is sublevel open-stoping on 200- foot lifts. Ample fresh air is provided by mechanical ventilation. Diamond drilling blast holes began in August 1944. Drills were mount- ed on a 3-inch quarry bar. The contract price for labor for operating equipment owned by the company was $0.23 per foot. The diamond bits were cast-set at the factory in a sintered tungsten matrix. Bit replacement costs were $0.15 to $0.20 per foot drilled. The feet drilled per bit ranged from 87 to 258. The feet drilled per diamond-drill shift ranged from 121 to 129. Holes were loaded with 60-percent special gelatin dyna- mite and fired electrically. In percussion drilling, the estimated feet drilled por machine shift with hand-held sinkers was 65. The tons broken per machine shift averaged 40 throughout the mine. Detachable bits have been adopted recently. The principal advantage of diamond-drilling blast holes at the Balmat mino is the extraction in a safe manner of ore not minable by short-hole drilling. The principal disadvantago is the greater cost per foot of holo in comparison with percussion drilling.

Jun 1, 1947

By R. S. Dean

A general survey of the metallurgical work of the U. S. Bureau of Mines has been given in an article in the Missouri School of Mines Alumnus, and a somewhat more detailed review of the bureau work on lead and zinc will be found in the Mining Congress Journal. C. C. Furnas has contributed one general mathematical article. Dean, R. S. U. S. Bureau of Mines. 4, 1930, pp. 7-8. Program of Metallurgical Investigations of the Missouri School of Mines Alumnus, vol. 4, No. Investigations of the U. S. Bureau of Mines on the Milling and Smelting of Lead and Zinc. Min. Cong. Jour., vol. 16, 1930, p. 799, 808. Furnas, C. c. Evaluation of the Modified Bessel Function of Am. Mathematical Monthly, vol. 37, the First Kind and Zeroth Order. No. 6, 1930, pp. 282-287.

Apr 1, 1931

By Nan C. Jensen, Oliver Bowles

Stone , the foundation of the continents and the floor of the oceans , is one of the most substantial and enduring of all substances that constitute the material universe . Stone furnished rude shelter for aboriginal man , and through all succeeding ages it has provided a lasting and serviceable structural material . Limestone is one of the most widely used building stones .

Oct 1, 1947

By R. R. Sayers

That the maintenance of proper air conditions is a most important factor in the control of occupational hazards is shown by the large amount of material presented each year through the technical journal's on the effects on workers of injurious dusts, gases, and variations in temperature and humidity.. SUMMARY OF RECENT LITERATURE ON EFFECTS ON WORKERS OF EXPOSURE TO DUSTS The subject of the control of dust and dust diseases continues to be a matter of serious concern in most of the industrial countries of the world, as indicated by the following summary of reports published in a number of foreign countries as well as in the United States. Australia. The Workmen's Compensation Act of 1920 for New South Wales3 provided for the promulgation of schemes for the compensation of workers dis- abled by silica or other dust. In 1924 the prevalence of silicosis and tuberculosis among Sydney stonemasons, quarrymen, sewer miners and rockchoppers was investigated by a Technical Committee of Inquiry, appointed upon the recommendation of the New South Wales Board of Trade. The findings of this committee were published by the Government in 1925. No scheme was promulgated by the Government and in 1926 the Act was amended limiting its scope to workmen disabled by disease caused by silica-dust. This was promulgated and gazetted on September 16, 1927, and applies to men working in sandstone as stonemasons, quarrymen, rockchoppers, and sewer miners in the County of Cumberland.

Feb 1, 1931

By R. W. Smith, S. H. Ash

Marked progress in safety has characterized the operation of coal mines in general in the State of Washington during the 5- year period 1928-1932 , particularly during the years 1931 and 1932. Physical conditions such as steep pitches , inherently bad roof and floor , prevalence of gas , and explosibility of the dust of Washington coals present certain definite hazards . Although advances have been made in accident reduction in Washington , the State still has far to go in that direction . The State has endeavored to reduce its coal -mine accidents by the usual method of making certain definite safety requirements mandatory . The value of education has not been underrated , but the educational method used has not altogether achieved the res lts desired by the industry itself , particularly within certain imdividual organizations . The past 2 years have witnessed a growth , in certain instances , of the essential ideas that the observance of safety precautions on the part of all is demanded if accidents are to be reduced , and that the initiating and carrying out of any program to promote and obtain desired results in accident elimination must begin and function from the top downward . Mining operations of Washington mines have been described in various publications of the United States Bureau of Mines .

Jun 1, 1933

By H. B. Humphrey

In the 39 years from 1891 to 1929 , gas and dust explosions in the coal mines of Tennessee caused 413 deaths , or one- third of the fatalities in the mines for that period . Inasmuch as explosions caused but about 15 per cent of mine fatalities for the whole United States for this same period it is evident that the Tennessee coal mining record is by no means good , as far as explosion fatalities are concerned . Since 1926 , Tennessee has had a clear record as to fatalities from explosions ; this fact may be credited very largely to the improved conditions and safer practices in Tennessee's coal mines which have been brought about by the work of the State Inspection Department and of the Southern Appalachian Coal Operators Association directed toward adoption of safety precautions and practices most of which are advocated by the United States Bureau of Mines . Chief among these improvements are the replacement of black powder and dynamite by permissible explosives , improved ventilation , and the installation of rigid methods of inspection for gas . With the present tendency for operations to pass into the hands of responsible and informed management , and with unrelaxed care and inspection , the good record of the past several years should be maintained .

Apr 1, 1931

By E. P. Youngman

The rapidly growing demand for titanium pigments has aroused new interest in actual and potential sources of supply of titanium- bearing ores , which only a comparatively few years ago were almost unmarketable . This paper , which supplements a general circular entitled " Titanium" ( Information Circular 6365 ) , represents a summary of current trade literature and Government reports , together with some hitherto unpublished material that has accumulated in the files of the Bureau of Mines . The purpose of this pamphlet is simply to indicate the commercial possibilities of the deposits , and the discussion is confined almost entirely to the three commercial ores , ilmenite , rutile , and magnetite ( titaniferous iron ore ) .

Oct 1, 1930

By A. L. Murray

First -aid training as an adjunct to safety is receiving more wide spread recognition in the industries every year . Moreover , the adoption of a program for giving firstaid training to practically all employees at a mine or plant is based upon the experience gained and good results obtained from standard first -aid instruction during the past two decades . In the near future industries that desire to maintain a low accident rate , to decrease compensation costs , to reduce lost time , and to build up an efficient , loyal working force , will recognize that training in first aid is one way of attaining these results with little expenditure of time and effort . Progressive organizations will require every man from the superintendent down to take first - aid training and not , as heretofore , only a small percentage of the working force . When employees learn that first - aid training can be applied not only at their daily tasks but in their homes and on tthhee highways ,, they will welcome the opportunity of learning how to care for injuries and perhaps save lives . In a limited way first - aid instruction was given to miners as early as 1899 . Later , in 1904 , a few of the companies in the Pennsylvania anthracite district inaugurated the distribution of first - aid packets to their employees and instructed them in the use of the contents . It remained , however , for a branch of the United States Government to grasp the real significance of widespread first - aid training as an effective means of saving life and minimizing suffering from the large number of accidents among workers in the mineral industries . The United States , owing to its vast resources , both natural and human , for

Jan 1, 1930

By L. C. IlsLey

The Bureau of Mines has collected field data and made laboratory investigations of trailing- cable performance in the hope of developing a better and safer cable for use with permissible mining machines . Because of their better insulation and performance , only rubber- sheathed cables were finally considered . The cables tested represented the product of six manufacturers . : After consideration of the results of the preliminary investigations , the conditions under which cables are used in mines , and the better performance of the later types of cables that were submitted as the investigation progressed , the bureau formulated a performance - test requirement and notified the cable manufacturers as follows : The hazards of the trailing cable are such that the bureau has been unable to extend beyond the machine its formal approval to cover the cable as at present developed . However , in the attempt to reduce the hazard as much as possible , cables passing certain tests will be recommended for this service and it is hoped that several cables will be developed to meet this requirement .

Sep 1, 1930

By E. J. Kloos, R. H. Schutz, B. I. Ferber

To protective devices, the Bureau of Mines has established five schedules of minimum performance requirements for the approval of respirators. The current revisions of these schedules include 13D for self-contained breathing apparatus, 14F for gas masks, 19B and the amendments to 19B for supplied- air respirators, 21B for dust, fume, and mist respirators, and 23B for chemical cartridge respirators. Copies of these schedules may be obtained from the Bureau of Mines, Publications Distribution Section, 4800 Forbes Avenue, Pitts- burgh, Pa., 15213. Approval tests on respirators are performed only at the request of the manufacturer of the respirator and at his expense. If the device meets the approval requirements, a certificate of approval is granted on the complete respirator. This certificate states that as long as the respirator is manufactured as originally approved, or in accordance with any changes covered by an exten- sion of the original approval, the manufacturer may advertise and sell his respirator as being approved by the Bureau of Mines. Many industries and regulatory agencies require that respirators approved by the Bureau of Mines be used where respiratory protection is needed. The Bureau of Mines, how- ever, has no regulatory power over the use of the respirators that it approves. It acts as an impartial testing agency to insure the availability of suitable and safe respirators. At frequent intervals, the Bureau of Mines purchases approved respirators and replacement parts on the open market. These are examined for conformity to the approved status, and are checked to insure that the manufacturer's pro- duction facilities are maintaining a satisfactory quality control.

Oct 1, 1965

By G. S. Scott. R. L. Grant

Ammonium nitrate (NH4NO3), a white crystalline chemical compound composed of 35 percent nitrogen, 60 percent oxygen, and 5 percent hydrogen, has again attracted attention, due largely to the recent catastrophe on April 16 and 17, 1947, at Texas City, Tex. The fire and subsequent explosion on the steamship Ocean Liberty, outside the harbor of Brest, France, on July 28, 1947, has fur- ther increased the interest in the properties of ammonium nitrate. As a result of the Texas City disaster, several laboratories have undertaken research to determine more certainly what causes ammonium nitrate to detonate and under what circumstances. This is not the first time that ammonium nitrate has been involved in a disaster, and its properties reviewed from the standpoint of safety. The disaster at Oppau, Germany, in 1921, which involved an equimolec- ular mixture of ammonium nitrate and ammonium sulfate, prompted an intensive study in Europe and in America. In the United States the properties of am- monium nitrate are now of especial concern because very large quantites are being manufactured and shipped in interstate commerce and abroad. Many an- monium nitrate factories, which were built during the war, will manufacture increasing amounts of this compound for use as a fertilizer. It is the purpose of this report to present a brief summary and biblio- graphy of the published experimental facts about the properties and behavior of ammonium nitrate. The reader is referred to original publications for greater details of the investigative work, and for theoretical discussions. This report also includes a survey of ammonium nitrate fertilizer of the type involved in the Texas City explosions. In the past, authorities have not always agreed on the degree of hazard involved in the manufacture and handling of ammonium nitrate, as the following quotations from the literature indicate: Munroe (82) quoted the following from Turner's Chemistry (a book pub- lished in 1835): "When this salt is exposed to fire, it liquefies, emits aqueous vapor, dries and detonates." Berthelot (14) in his book, Explosives and Their Power, 1983, wrote: "Ammonium nitrate from the point of view of its volatility, and cn account of many considerations, may be regarded as a typical explosive substance."

Jun 1, 1948

By E. P. Youngman

The mining laws of Russia (Collection of Laws, vol. 7, 1912) are still in force in Latvia. The Free State of Latvia (declared independent on November 8, 1918) is composed chiefly of the Baltic Provinces of the former Russian Empire, which are ethnographically Lettish: The Province of Courland, four districts of the Province of Livonia, and three districts of the Province of Vitebsk. Since the establishment of its independence, Latvia has not felt the need of a special mining law, inasmuch as mining so far has not been found profitable in that country. A supplement to this paper, entitled "Mineral Resources," is a brief summary of the minerals found and utilized in latvia. RIGHTS OF FOREIGNERS A foreign individual is permitted to explore for minerals and to own and operate mines in Latvia on equal terms with Latvians. A foreign corporation is required to establish a branch in Latvia, which shall be subject to the corporation laws of the country. A certain number of the partners or incorporators must be citizens of Latvia.

Nov 1, 1931

By D. Harrington

Along with other phases of mining , the ventilation of metal mines has been affected by the business depression of 1930. As might be expected , some of the results are favorable , and some are distinctly disadvantageous to progress . Probably the worst effect of the recession of mining activity is that , as usual , one of the first departments of almost any industrial establishment ( and this is especially true of mining ) to be curtailed is that which concerns what might be called welfare work , such as safety , health , etc. , and ventilation : in consequence , a number of men who were employed mainly on ventilation work in metal mines are now out of employment and their former duties either are being handled by others as only part of a crowded routine or are being allowed to lapse . On the bright side of the picture is the following paragraph from a letter by the ventilation and sarety engineer of the United Verde Copper Co. , Jerome , Ariz . , indicating that money and effort expended on ventilation during " flush " times give results which aid in money savings when depression comes : The desirability of absolute control over the ventilation system has again been demonstrated at this mine . Under full operation we have been using approximately 500 hp . to drive our big fan . Under curtailed operations we naturally do not require as much air , so by sending the air only where needed and airing out all other places periodically to keep timber , etc. , in good condition we have been able to economize in the quantity of air required . The fan speed has been reduced and the power dropped to 300 hp . , thus effecting a material saving in the power bill , and still maintaining an efficient ventilating system . "

Jul 1, 1931

By E. P. Youngman

This digest, based upon a translation" of certain portions of the 1930 law, covers the pertinent points of what has been termed "The New Mining Law of Luxemburg," the Grand Ducal Order (Arrêté) of April 26, 1930, concerning the exploitation of "mines, minières, and carrières, 4 and abrogating the order of January 2, 1891, concerning the same subject." The Duchy of Luxemburg, which between 1735 and 1815 was French, adopted as its basic mining law the French Law of April 21, 1810, and an Imperial Decree of January 3, 1813. The Luxemburg Government later supplemented and modified this legislation by the laws of June 12, 1874, April 30, 1890, and May 10, 1898, which, with article 36 of the Constitution, are to be taken into consideration in a complete survey of mining legislation. The order of

Apr 1, 1933

By E. P. Youngman

In this island, which is a Crown colony of the British Empire, and where remarkably extensive remains of ancient mining operations-- mainly for copper--exist, the mining law of Turkey governs, rith such modifications as were made necessary by the transfer of the country in 1878 from Turkey to Great Britain, and with such fer ameliorations thereof as have since been ordered by the local authorities. The Turkish law to which Van agenen refers is, no doubt, "2 Shaban, 1285," which though subsequently repealed with respect to Turkey is still in force in Cyprus, inasmuch as the mines regulations (amendment) law of 1925 "is to be read in connection with 2 Shaban, 1285" (articles 61 to 67 of which were repealed by the law of 1925): In the preparation of this digest; access was had to the mines regula- tions (amendment) Iaw, No. 5 of 1882; which Van Wagenen does not mention. Other Cyprian laws, passed since the publication of Van Wagenen's work in 1918, are the following: Eines regulations (amendment) law, 1925, No. 12 of 1925; mining-prospecting permits; notification, No. 539 of 1927; mines regu- lations 1926, No. 1006 of 1926; mines regulations (amendment) rules of court, 1926, No. 144 of 1926; mines regulations (amendment). 1a, 1928, ko. 3 of 1528 (as amended by No. 32 of 1928). Most of these làrs are concerned with the regulation of actual mining operation--safety and sanitary provisions; and, therefore, they ado little important information. The Cyprian Government's official publication says: It is considered that the laws regulating mining in Cyprus are inadequate and antiquated, and a thorough revision is necessary to bring them up to a standard of modern mining practice and to encourage mining ventures in the island. As a preliminary to this the mines regulations, 1926, were issued to govern the workings of the larger mines; and serious attention is now being given to the regulating of prospecting, quarries, machinery in mines, and generally to the bringing of mining in Cyprus into conformity with the other mining countries of the world.

Jan 1, 1933

By IRENE AITKENS

The emerald is the most costly of all gems , due to the scarcity of flawless stones . This fact gave rise to the ancient axiom , " As rare as an emerald without a flaw . The finer gems not only command the highest prices at all times , but when flawless are considered the most highly prized of all gem stones . George F. Kunz divides emeralds into two distinct classes : " Exceptional specimens , " which bring as much as $ 6,000 a carat ; and " fine- quality specimens , " which bring about $ 1,000 a carat .

Jul 1, 1931