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By R. S. Dean

The development of metallurgical processes may be divided into periods : First , the discovery of a basic reaction which brings about the production of the desired product from the available raw material ; second , a long stage of mechanical development during which little or no attention is paid to the reaction itself ; and third , a careful study of the reaction . Most metallurgical processes are to -day approaching the end of the second period . This we may illustrate by the steel process . The reaction of carbon with iron ore to produce pig iron and the subsequent refinement of the pig iron by an oxidation reaction is very old . Development in modern times has been almost entirely mechanical , the development of the blast furnace , furnace , the Bessemer process , the Siemens process , and even the Aston process for wrought iron being mechanical improvements almost entirely . Metallurgy is now entering a phase where the reactions are being considered . The question of how far can they be made to proceed is being repeatedly asked . As mechanical processes are improved , we approach a limit to which our basic reactions can be pushed which is determined by the nature of the reactions themselves . We want to know : How far can iron be decarbonized by iron oxide ? How low can the oxygen of copper be reduced by any given reaction? How efficiently can the fuel in a zinc reduction process be used ? The demand for purer metals and lower production costs has forced these and similar questions upon us . How are we to answer them ? The determination of these equilibria or end points of metallurgical reactions by direct means is fraught with difficulty because here we must overcome mechanical difficulties which too often become the limiting factors even in the laboratory and we do nottherefore get the actual limit to which the reaction itself may be carried . Further , there are so many reactions of metallurgical materials that to survey each separately is a job to give pause to any experimenter or group of experimenters .

Dec 1, 1930

By Scott Turner

We have gathered here in Pittsburgh, at the Nineteenth Annual Safety Congress, in order to advance the cause of safety. Although my personal inter- est in this movement alone would have been sufficient to insure my presence here, specific duties have brought me to this congress in an official capacity. My responsibilities as the head of the United States Bureau of Mines, which makes the promotion of safety in the mining and allied industries one of its major activities, necessitate my attendance. My obligations as president of the Joseph A. Holmes Safety Association, an organization closely allied to the bureau and which has for one of its objects the public recognition and reward of outstanding achievements in safety, require that I be present at this time. This morning, my job is to present the Holmes safety certificate to the Lehigh Portland Cement Co. First I will remind you of the nature of this safety association, named in honor of the first director of the Bureau of Mines. After Mr. Holmes' death, in 1915, a number of influential organizations banded together to commemorate the name of this leader in the conservation of human life. In order that you may appreciate the significance of an award by the Joseph A. Holmes Safety Association, I shall read you the list of 24 national organizations which comprise its membership:

Nov 1, 1930

By E. Wittenau

This paper describing the concentrator practice of the Copper Queen Branch of the Phelps Dodge Corporation at Bisbee, Ariz., is one of a series of papers on milling methods and costs being prepared by the United States Bureau of Mines. The Copper Queen Concentrator treats 4,000 tons of copper ore daily by preferential flotation, whereby the copper sulphides are floated and considerable iron pyrite is depressed. During 1929 the heads to the concentrator averaged 2.15 per pent of copper, the recovery was 91.32 per cent of the total copper, and the concentrates produced contained 12.92 per cent of copper.

Jan 1, 1931

By Allan J. Clark

This paper, describing the milling practice of the Homestake Mining Co., is one of a series being prepared by the Bureau of Mines. The author acknowledges the assistance of T. G. Chapman, one of the consulting engineers of the Bureau of Mines, in arranging this paper for publication.

Jan 1, 1931

By Chas. F. Jackson

This paper is one of a series dealing with mining methods and costs, prepared and published under the sponsorship of the United States Bureau of Mines and made possible through the cooperation f many mining companies in the United States and foreign countries. The preparation of this paper follows a field study of top-slice mining during which the author visited and discussed with operating officials a large number of iron mines in the Lake Superior region. During this study special note was made of changes in top-slicing practice during the past decade, prior to which the author had acquired several years experience with the method through active connection with a number of mines employing top slicing.

Jan 1, 1931

By R. D. Currie

A study of the accident statistics in the coal mining industry convinces one that an organized effort must be put forth to prevent the vast destruction of human life in this industry . The fatality rate in Pennsylvania has not improved in the past several years and during 1928 it was higher than the average for the period 1916 to 1927 , inclusive . Although the accident rate for this State is less than that of the coal mines of the United States as a whole , nevertheless the rate is unduly high ; however , there are many companies which have exceptionally good records as regards both fatal and nonfatal accidents . A study of the methods used by some of these relatively good- record companies to reduce accidents in their mines shows that they exert an organized effort to prevent accidents , and that their safety organizations usually affect every employee in and about the mine from the highest official to the check boy . The chief executive must be actively and personally interested in accident prevention if real safety results are to be obtained ; when he shows this interest it is almost invariably reflected in the officials under him and throughout the organization . Safety organizations vary in form and are readily changed or adapted to the varying conditions found in the bituminous field . The companies whose organizations were studied in preparing this report are all getting good results , and it is their opinion that the safety organizations have been a big factor in obtaining these results . At their request the identity of some of the companies whose organizations were studied has not been divulged in this paper , but this does not affect the value of the information concerning their safety organizations .

Mar 1, 1931

By Wm .. O. Vanderburg

This paper describing the mining practices at the Block P mine of the St. Joseph Lead Co. at Hughesville , Mont . , is one of a series of similar papers being prepared by the Bureau of Mines on mining practices , methods , and costs in the various mines of the United States .

Mar 1, 1931

By Wm. O. Vanderburg

This paper describing the mining practices at the Block P mine of the St. Joseph Lead Co. at Hughesville, Mont., is ore of a series of similar papers being prepared by the Bureau of Mines on mining practices, methods, and costs in the various miner of the United States. ACKNOWLEDGMENTS In the preparation of this paper the writer acknowledges the assistance of R. H. Willcomb, general manager, William Thorson, mine superintendent, and B. P. Bellport, mining engineer, of the Hughesville division of the St. Joseph Lead Co.; and of E. D. Gardner; supervising engineer, U. S. Bureau of Mines, Southwest Experiment Station, Tucson, Ariz.

Jan 1, 1931

By D. Harrington, C. W. Owings

The mining industry is gradually realizing that safety education and safety inspection are economic factors that may not be overlooked as a means of reducing operating costs . Many mine operators , however , have failed to realize the benefits of safety , and the efforts of the more progressive mining companies are offset by the carelessness of neighboring companies when the accident records of a community or a State or the nation as a whole are considered . This tendency is indicated by the data collected by the safety division of the United States Bureau of Mines . During the fiscal year ended June 30, 1930 , relatively definite information: was secureä concerning 34 mine explosions , 24 mine fires , and 29 miscellaneous accidents ; these accidents are by no means all of the explosions , fires , and miscellaneous accidents which occurred in the mines of the United States during the period; but the data on the fires and explosions constitute a record of all of those types of accidents that were called specifically to the attention of the safety division , and the miscellaneous accidents include those on which definite , detailed data were obtained by the safety division .

Jan 1, 1931

By R. G. O'MEARA, Alexander M. Gow, W. T. SCHRENK

Lime is used extensively in the various industries. The National Lime Association in an excellent and recent bulletin lists 23 important in- dustries in which lime plays a vital role; and it thereby justifies the statement that "Lime is one of the most versatile and widely used reagents in the chemical and industrial world." There is, however, one application of this "universal" reagent which has not been mentioned. It is the use of lime in the flotation of ores. An appreciable percentage of the lime produc- tion is consumed by ore-dressing plants. The uses of lime throughout all the industries are more or less re- lated, but "lime" is a broad term; the varieties of lime are more mumerous than the limestones from which it is made, and its use involves a complicated technique. The interrelated application and growing importance of lime in flotation warrant this additional publication on the various "limes," with emphasis on those uses related to the function of lime in flotation. ཁྐྲ་ Lime in water treatment, cyaniding, and amalgamating will be men- tioned, after which its use in flotation will be taken up. This compendium was prepared by the Mississippi Valley Experiment Station of the United States Bureau of Mines and the Missouri School of Mines and Metallurgy, Rolla, Mo.

Apr 1, 1931

By John D. Sullivan

The recovery of copper by leaching from relatively low grade ores containing both oxidized and sulphide minerals is rapidly gaining in commercial importance. There is an economic limit below which certain ores can not be treated by concentration methods, and material with values below this limit must be discarded, possibly to be treated later, or the copper must be extracted by wet processes. Heap leaching has been carried out by the Phelps Dodge Corporation, Copper Queen Branch, for several years, and to-day its plant is a large producing unit. The Ohio Copper Coy at Bingham, Utah; has been leaching in place since 1919. Many other leaching operations are also being; carried out in various parts of the United States and in foreign countries. The plant at Rio Tinto, Spain, may be considered the father of heap leaching.

Jan 1, 1931

By Worthen Bradley

This paper describing the metallurgical practice and costs at the reduction plant of the. Sulphur Bank Syndicate, Clearlake, Calif., is one of a series of papers on the treatment of ores being prepared by the Bureau f Mines. The reduction plant and mine of the Sulphur Bank Syndicate are on the eastern shore of Clear Lake, in Lake County, Calif., 4 miles from the town of Clearlake and 125 miles north of San Francisco.

Jan 1, 1931

By Arthur H. Redfield

The expansion of city street laving which characterized the ten years ended December 31, 1929, according to a survey of 201 representative cities, made by the bureau of Mines, reached it climax in 1927, with decreases reported for 1928 and 1929. The upward trend, followed by a decline, was general in cities of all sizes included in this study, but was most pronounced in cities of 40,000 to 100,600 inhabitant and in the Northeastern, Southeastern, and Southwestern States. In the North-Central States the trend of paving; was downward from 1925 to 1929; in the Pacific, and Rocky Mountain States it was generally upward. Over the nation as a whole, bituminous types of paving continued to lead, furnishing two-thirds of the total street pavement laid in the 201 cities from 1925 to 1929. The actual yardage of bituminous pavement laid in these cities, however, was 3.8 per cent less in 1923-than in 1925, and the ratio of bituminous pavement to the total pavement t dropped from 70.4 per cent in 1925 to 62.1 per cent in 1928, rising to 65.1 per cent in 1929. The area paved with Portland-cement concrete amounted to only one-fourth of the total, pavement laid in these cities from 1925. to 1923., but the yardage of Portland-cement pavement increased by half during the period, and its share in the total pavement grew from 19.3 per cent in 1925 to 30.0 per cent in 1928, declining to 29.5 per cent in 1929. Brick, block, and stone pavements, which constituted the remaining one-twelfth of the total pavement laid in the 201 cities, decreased one-third in yardage, and declined in relative importance from 10.3 per cent in 1925 to 6.6 per cent in 1929.

Jan 1, 1931

By Ronald A. Vary

This paper is one of a series prepared by the United States Bureau of Mines dealing with milling methods and costs. In view of the current revival of interest in gold mining, information dealing with practices and costs in the development of gold properties is apropos. Milling practice at a small gold property in the prospect stage is described where, with a small outlay for plant and equipment, development has been carried on for about 20 months on the proceeds of the mill operation with little additional expenditure. The paper shows about what may be expected as to costs at a small property operated under northern climatic conditions and with rigid economy throughout the plant.

Jan 1, 1931

By M. W. Von Bernewitz, J. J. Forbes

"In the United States there are hundreds of underground and surface (inside and outside) inclines at coal mines on which trips of cars are continually being run with coal, rock, supplies, and men. The safety of the men and prevention of damage to the slopes depend, excluding the personal element of the hoist-man, on the strength and condition of the wire cable, draw bars, and the couplings, and on the links of chains and pins as well. Within a recent period of four weeks there have been two runaway trips, one on the surface and one underground; it seems desirable to call attention of mechanical engineers and others at coal mines to the need for closer and more frequent inspection of the cable, draw bars, coupling links and pins, derailing devices, wheels, brakes, and other parts of cars or trips on which men are hauled on inclines. This bureau has never published anything on this class of accident heretofore.How frequently runaway trips occur is not known. If no serious injury or fatalit has to be reported to the State authorities, a number of such happenings may occur and not be mentioned outside of the immediate vicinity of the mine.Runaway trips can and do result in considerable loss of life, in injuries, and damage, either at or near the place of the break, or throughout a mine by causing an explosion of gas or coal-dust or both, This report is restricted to a study of the mechanical and physical phases of car trip construction and of the metal of couplings and ropes; derailed trips are not included and may be the subject of another paper. There is no need to mention gas accumulations, coal-dust and rock-dusting, open lights, protected power lines, and permissible equipment, because these have all been well covered in Bureau of Mines publications which have been widely distributed and partly or wholly reprinted by others.Most of the items regarding the runaway trips tabulated have been abstracted from reports made respectively by Clarence Hall, W.O. Snelling, and J. W. Paul; D. Harrington and J. J. Forbes; H. C, Howarth and G. S. McCaa; K. L. Marshall and E. H. Denny; J. J. Forbes, G. W.- Grove, and R. D. Currie; S, P .Howell and K. L. Marshall; and .J. W. Paul, H. D. Mason, and G. E. McElroy, all of the mining and safety divisions; and C. H. Herty, jr., and G. R. Fitterer of the metallurgical section of the Bureau of Mines. W. J. Fene, K. L. Marshall, and S. P. Howell of the safety division, and J. F. Lessig, mechanical engineer, and G. St. J. Perrott, superintendent, Pittsburgh Experiment Station, read the text and offered sugges¬tions. W. J. McGregor, coroner for Allegheny County, and P. F. Nairn, State Mine Inspector of Pennsylvania, contributed valuable information."

Mar 1, 1931

By Paul M. Tyler

Magnesite is of importance primarily as a refractory material for lining steel furnaces , although substantial amounts are used in the production of flooring compositions and other building materials and for certain chemicals , notably epsom salts . Since consumption for all of these purposes is largely in the eastern United States and domestic deposits are situated in California and Washington , this country's magnesite mining industry , which was created largely by war- time conditions , has subsequently been sustained by tariff protection .

May 1, 1931

By PALMER LARSEN

INDEX TO GEOPHYSICAL ABSTRACTS

May 1, 1931

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 T. W. Quayle

This paper describing mining practices at the United Verde copper mine, Jerome, Ariz., is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts f the United States. At present mining operations are being conducted both underground and by electric shovels in an open pit. The open-pit work has been described by E. M. J. Alenius in a previous publication of the Bureau of Minos;3 the present paper will be confined to a description of the underground mine. The underground methods comprise horizontal cut-and-fill, shrinkage with delayed filling, horizontal square-set, inclined square-set, and top slice. The normal daily production of the underground mine is 3,000 tons of copper ore per day, requiring the employment of 900 men underground.

Jan 1, 1931

By JOEL H. SWARTZ

During a series of resistivity measurements carried out in 1929 and 1930 a number of questions arose concerning the effect of topography on the character of the curves and the depths attained , the ratio of true depth to certain radii interpreted as representing depth , etc. To answer these questions it was decided to undertake a series of experimental investigations on artificial strata . It is the purpose of the present paper to present the results of the studies thus undertaken .

Feb 1, 1931