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By Alexander L. Holley

(WITH FIGURES ON PLATE I.) A CHARACTERSSTIC, and, to Americans, an amusing discussion of the three-high rail-mill, arose out of the reading of Mr. Lauth's paper on three-high plate-mills, at the Glasgow meeting of the Iron and Steel Institute. From the report of the meeting in the English papers, it appears that Mr. Menelaus, the celebrated rail-maker of Dowlais, could not wait for the discussion of Lauth's plate-mill, but launched at once into the British objections to the three-high rail-mill, which is quite another matter. The American mill, which is very different in principle and ar-

Jan 1, 1873

By J. W. Snavely

THE part that acceleration plays in starting a belt conveyor and its effect on belt conveyor design are well understood in a general way. Its practical importance is easily overlooked, however, and under some conditions, it is absolutely necessary to give the problem of acceleration detailed study. Most handbooks on conveyor belting design adequately present basic data for the determination of acceleration values. This paper will only attempt to present practical thinking and a convenient method of treatment of acceleration in belt conveyor design. Mathematical Analysis In working out the various problems of conveyor belt acceleration, the starting point, as presented by the handbooks, is the familiar formula of "force of acceleration is equal to the mass times acceleration." By expressing these fundamental quantities in terms of belt conveyor design, it is possible to arrive at the unsuspected conclusion that the acceleration time for horizontal belt conveyors is independent of the load, and instead, dependent upon the belt speed, the type of drive arrangement and drive pulley, and the idler coefficient of friction. The mathematics leading to this conclusion are shown in Table I, which has been prepared to show, this derivation. While at first the conclusion just given may not seem to be reasonable, further reflection indicates that obviously the type of drive pulley and the type of drive do affect materially the tension in the conveyor belt, and thus, as clearly shown, the time of acceleration is dependent upon the factors mentioned. Inasmuch as all of the factors except time are predetermined by the belt conveyor design, it becomes relatively easy to establish the accelerating time and to reduce further this time determination to a simple graph from which the time in seconds can be read directly. Such a graph is given in Fig. 1. The table appearing on Fig. 1 should be explained further. For a given belt speed, the time of acceleration can be expressed as a percentage of the belt speed. The time of acceleration is also dependent on the drive arrangement, and changes in the drive arrangement consequently change the time of acceleration. It further follows that for a given belt speed, the time expressed as a percentage of that belt speed also changes with the type of drive. Obviously then, it becomes possible to graph the percentage of speed for each type of drive against the belt speed and accelerating time, after which, for a given belt speed and type of drive, the time can be read directly in seconds. Two constants were established for Fig. 1, the first one being the limiting of the maximum acceleration tension to 35 pct of the full load operating tension in the belt. The purpose of this is to limit the total tension imposed upon the belt during the acceleration period to 135 pct of the full load operating tension, which is the amount required to start or breakaway the fully loaded belt conveyor from rest. The other constant is the friction factor used for the idler equipment, which has been established as 0.022. For installations where it is necessary to establish the values of acceleration, invariably high grade idler equipment is used, and it has been established from. field experience that 0.022 for the idler friction factor is amply conservative. The use of this friction factor for idlers must be tempered with judgment, of course, for occasions will arise where more power than indicated is required to start, even with the very best of equipment, such as low temperature operations that tend to congeal the grease in the bearings and thus produce additional friction drag. An inspection of the table in Fig. I affords a convenient rule of thumb method for determining the acceleration time, which conveniently can be 5 pct of the belt speed in seconds. The 5 pct of belt speed figure is close to the average for most types of drives. In using Fig. 1 it must be emphasized that it applies accurately to horizontal belt conveyors only.

Jan 1, 1952

By Ingersoll Olmsted

These ores are of two classes, Bessemer and non-Bessemer, existing in separate, though adjoining, beds. Both are carbonates, with small admixtures of oxides and other combinations. To prepare them for market they are roasted in kilns, which have already been described by Mr. John Birkinbine at the Troy Meeting, October, 1883 (Trans., xii., 378). Concerning their size, arrangement, etc., I need, therefore, only repeat that they are 60 feet in height; have wrought-iron shells 24 feet in diameter; are lined with fire-brick, and supported by cast-iron mantel and columns.

Jan 1, 1889

HAVING described and taught you the method of assaying silver for gold in the preceding chapter, and therein having proceeded in the order and Drover wav followed in the working of quantities of gold and silver, I could have fled this task of describing to you the first part of parting. In truth, there is no other difference in the method of arriving at the end except in respect to certain precautions that must be taken against the dangers causing loss. In order that you may guard against these, I shall repeat the procedure completely, in addition to the second part of this art, which is the method of reducing the silver to its body.

Jan 1, 1942

By T. E. Schwarz

The publication of the report by Mr. F. L. Ransome1 was welcomed by many engineers who had mined in the heart of the San Juan country, braved its long and snowy winters, climbed its lofty peaks, run the gauntlet of its snow-slides, and studied its problems of geology, while making dividends for their English or American clients. This report helps one to understand why the bonanzas occurred, and why the inevitable " borrasca " presents itself where least expected. The Red Mountain district of Ouray county, a very productive section from 1884 to 1893, occupies considerable space in the report mentioned. The character of the ore-occurrence.

Jan 1, 1906

By Robert Pring

IN addition to the humanitarian aspects of a dust-control program, certain economic benefits are becoming more fully recognized and now furnish a greater incentive to the mill operator to eliminate the dust from his plant. It is well known that a favorable working environment promotes increased efficiency and improves the morale of em-ployees, with a consequent decrease in labor turnover rates. One progressive mining company estimates its direct and indirect labor turnover costs at from $40 to $50 per man; for skilled labor, such as machine operators, the cost may approach $100 per man. While these figures may not be typical of every plant, they do indicate a potential savings in operating costs. Dust signifies waste; its elimination de-creases maintenance costs of mechanical and electrical equipment; its recovery is often justified from the standpoint of values contained in the collected material, although in large-scale milling operations handling low-grade ore this may not be an important factor. Perhaps the most significant trend in industrial sanitation is that dust-control equipment and procedures are becoming recognized as integral parts of the mill flow-sheet. Exhaust ventilating systems are now afforded equal care in design and mainte-nance to that given other machinery more closely related to the process,

Jan 1, 1940

By W. A. Backofen, M. L. Ebner, D. H. Avery

Slip on (11221 planes, which do not contain a close-packed direction, has been identified on crystals strained at —190°C. Evidence is also presented to show that (1071) pyramidal slip is a mode of deformation at 25ºC in a limited orientation range. PYRAMIDAL slip (l011) <1120> in magnesium at elevated temperatures has been established for some time.1-2 More recently, Burke and Hibbard reported this mode of deformation at 25"C, but their results were questioned by Craig.&apos; Also, as far as the present authors know, slip in magnesium on pyramidal planes of the second order, Type II (1122)) has not previously been reported, although Gilman"," identified (1122) slip in another hexagonal metal

Jan 1, 1959

By Henry J. Kaiser

A few months ago I had the honor of addressing the Society of Mining Engineers annual banquet in Sun Francisco. I have since been asked to amplify some of the remarks I made at that time concerning the management policies of the Kaiser organization and various aspects of our corporate thinking. This is a difficult task for an insider like myself. I look at the different companies, and the men who run them, and it is hard to think of these men in terms of policy or procedure. Actually I prefer the term management philosophy to either policy or procedure. My father, Henry J. Kaiser, is not only the founder but the guiding spirit of our organization. His philosophy, and in turn that of the organization, centers around two concepts, service and accomplishment.

Jan 1, 1960

By M. D. Cooper

Production of both anthracite and bituminous coal in 1954 was about 16 pct below 1953. Estimates on Dec. 1, 1954, indicated 27 million tons of anthracite and 385 million tons of bituminous. Decline in production was due principally to lower demand by the steel industry and the railroads, although competition from other fuels also affected coal. The year was notable for vigorous effort by the coal industry to promote the use of its product. A Cabinet Committee on Energy Supplies and Resources Policy and an Interdepartmental Committee on the Soft Coal Industry were set up by the Administration in Washington. A Governors&apos; Fuel Conference was also organized.

Jan 3, 1955

By Armand Bur, W. R. Reichenstein

Since coal is one of the largest cost items in the production of electricity, its analysis for heat value and composition has been the subject of intensive study. Sampling started with crude hand methods, out of the railroad car or barge or from moving conveyor discharge, and progressed to reliable mechanical in-plant sampling systems. The mechanical system takes its sample from a falling stream of coal such as a conveyor discharge or crusher discharge hopper. But this has a disadvantage in that the identity of the coal is lost. Coal is shipped to the user in train-loads, often made up of shipments from various mines. When the cars are dumped into hoppers and the coal conveyed to the power station, the various shipments become mixed because residual coal remains in hoppers and chutes.

Jan 5, 1959

By Milton C. Neul

As recently as the mid-1930&apos;s, steam and rail haulage were still the primary means of moving large quantities of rock. However, 2- to 5-ton standard on-highway trucks were beginning to be used in the mining industry&apos;s efforts to lower haulage costs. It was quickly obvious that rubber-tired equipment was more flexible, faster and more maneuverable. The trend towards haulage trucks had begun. Now while savings were being realized, the severe operating conditions encountered in open pit operations proved too much for the lightly constructed frames, gasoline engines and highly inflated tires. As a result, a few years later, the first 10 to 15-ton, two-axle heavy duty trucks were designed specifically to operate under off-highway conditions.

Jan 3, 1966

By Michael Richings

Although the role of slope stability has not changed, there have been changes in the mining industry which affect the geotechnician engaged in slope stability studies. The deposits currently being mined or evaluated are technically difficult , capital intensive, and economically marginal. In addition, many mining companies are now either controlled by oil companies or are financing projects through bank loans. The mining investor or decision maker is, therefore, often more sophisticated financially, but less sophisticated in mining terms. The impact of these changes will be to force the geo- technician and mining engineer to attempt to quantify risk and financial implications of a slope design. In conclusion, this paper outlines several questions which mining engineers should be asking those engaged in geotechnical studies and indicates the necessity for the mining engineer and geotechnician to work together and quantify the financial risk associated with a geotechnical design.

Jan 1, 1983

There are not many data about early coal production in Kentucky, but some legislative reports, early geological studies and occasional newspaper articles have left some figures. The earliest production with any authentic record is that of Lee County, the coal being boated down the Kentucky River to Frankfort. While never a large producer, this county has the longest record in the State. Production is recorded in several of the western coal counties in 1820, and in several others a few years later. The early production in Greenup County was for the iron furnaces operating there. Clay County had a large salt output in the early days and this required a large output, for those days, of coal; the amount of fuel is based on the quantity of salt. It will be noticed that several counties on the Ohio River produced considerable quantities of coal before the Civil War, much of it being consumed by the river steamers. Since the end of the war, these counties have never occupied the relatively important position they had prior to that time. All of the coal produced in the eastern mountain counties moved out of them by water before the war, and during that struggle nearly all mining was stopped. The growth of the railroads after the war greatly reduced the river traffic from these counties, and in some cases it was never renewed. The coal shipped from Lawrence County prior to 1861 all moved by water; after that date there was no production excepting for local use until 1879, and since that time, all shipments have been by rail. Some of the early railroad reports have been helpful in reporting shipments, but for the early years very few of them can be found, and after about 1879 the quantities reported cannot be identified as to origin. Pres. J. B. Hill, Louisville and Nashville Railroad, furnished all of the data available for his line. Sources of data are shown on Table 61; other figures are estimated. A list of early Kentucky mines is given in Table 13.

Jan 1, 1942

By D. K. Crampton

NEARLY everyone who has not had the benefit of study in the field of metallurgy subscribes to a persistent and enthusiastic belief in the legendary lost art of hardening copper. This of course supplies a perfect introduction to a chapter of information on copper and its alloys, since the dissipation of fallacies and superstitions affecting an art probably constitutes the best method of getting at its real substance. Metals are hardened, but also embrittled, by a plurality of impurities. In the modern technology of copper-base metal products, we are familiar with a great host of materials, passing from one extreme of dead soft copper better than 99.9 pct pure, which in the form of wire about as thick as a match will stand hundreds of full twists in a 12-in. length, to an alloy containing less than 3 pct of alloyed substance possessing the strength of pretty good steel and capable of manufacture into razor blades, should we suddenly be deprived of steel; certainly a much better material for this purpose. Every copper alloy known to primitive man lies in some inter- mediate position and the ancient bronzes that have been found all over the world wherever an early civilization existed are usually contaminated by such impurities as sulfur, oxygen, antimony, arsenic, iron, or other materials, so that they could not possibly conform to any modern intelligent specification insuring the best combination of useful properties in alloys of their type and would go

Jan 1, 1953

This study of engineering education arose out of the action of a joint committee on engineering education, representing the principal engineering societies. The committee had gathered so much material that it decided the work could best be carried out by some one trained in applied&apos; science, who would devote his entire attention to the study.. The Carnegie Foundation therefore asked Prof. Charles R. Mann, of the University of Chicago, to undertake the work. After making a thorough study Prof. Mann has made a most comprehensive report. In it he says: The engineering schools of the United States began their work upon a definite teaching plan and one that had at least pedagogic consistency. But during the past half century the course of study has been overlaid with many special studies intended to enable the student to deal with the constantly growing applications of science to the industries. As a result, the load upon the student has become so heavy that there is a feeling that the students fail to gain a satisfactory grounding in the fundamental sciences and do not fulfil the expectations of engineers in d manufacturers in dealing with the practical problems with which they are confronted on leaving school. At present 60 per cent. of those who enter the schools fail to graduate, still many of them persist in engineering and make a success of it. It is evident, therefore, that the present systems of admission are not satisfactory. If a group of schools will take up the careful study of their entrance systems and experiment with objective tests and records of the students&apos; youthful interests and achievements, the percentage of elimination can be reduced to at least a fourth of its present size, with an enormous saving of time, energy, and money for both student and school. The number of required credit hours per week should be less than eighteen, preferably sixteen. The few experiments that have been made indicate that college students do their best work when not more than five subjects are studied at a given time.

Jan 1, 1919

By James C. Fisher

Traditional uranium exploration techniques were utilized and comparatively evaluated in the Front Range, Colorado uranium province. Intense surficial leaching and thick colluvial cover render traditional airborne and ground radioactivity reconnaissance prospecting useless. Radon gas emanometry and sulfur gas emanometry were slightly more effective but the long and short term variations In soil gas emanation rates make it extremely difficult to gain useful information from these systems. The technique judged most useful was Track Etch radon prospecting. The excellent definition of the technique, as well as its repeatability, indicate that it is an ideal prospecting tool for narrow vein-type deposits similar to those of the Front Range, Colorado.

Jan 1, 1976

By Fred T. Greene

(San Francisco Meeting, September, 1915) MOST of. the recent discussion of the mineral land law published in the Transactions is in the abstract-an exception being Mr. Goodale&apos;s paper, The Apex Law in the Drumlummon Controversy,1 which illustrates in concrete instances many of the practical disadvantages of what Dr. Raymond has. called "The Law of the Apex." The present paper, it is hoped, may serve a similar purpose, emphasizing the necessity for a change in our mining laws, and bringing home to mining engineers some of the defects and dangers of our present code. There are many storm centers of "apex litigation" in the Rocky Mountains; and not the least of them is the Wardner camp, where such litigation has been almost continuous since 1892, and the end is not yet. In their decisions, the courts have accepted the claims of the litigants that the " Wardner vein" is a broad zone varying from 250 to 500 ft. in width at the surface. This is the simplest theory which could have been advanced, and probably decreased, rather than augmented, the number of contests; in fact, every one of the claim owners seemed to feel that the greatest advantage would accrue to him if this theory were adhered to. The dominant structural feature of the Wardner vein is a persistent fault, striking N. 40° W., clipping about 40° to the southwest and called the "Wardner foot wall." Fig. 1 is a composite of two adjacent cross-sections of the vein and is a fair representation of the relative size and shape of the orebodies and their relation to the "Wardner foot wall." The country rock is a comparatively thin-bedded sericitic quartzite which has an average strike of N. 80° W. and clips at high angles to the north and south.

Jan 5, 1915

G. SHERBURNE ROGERS,* Washington, D. C. (written discussion ?).- Mr. Neal&apos;s paper on the petroleum hydrology of the Mid-Continent district is a welcome contribution on a subject concerning which none too much is known; it is, I think, the first published description of the chemical character of the oil-field waters of the great Mid-Continent area. When studying the oil-field waters of the California fields several years ago, the differences in chemical composition between waters occurring at various horizons seemed to be sufficient to enable the operators to use water analyses as a basis for determining the source of the water flooding a well; and it is gratifying to find that, Mr. Neal has arrived at a similar conclusion. As Mr. Neal points out, the Mid-Continent waters are very different in character from those of the California fields, and casual. inspection

Jan 3, 1919

By S. H. Ash

THE increasing need for the products of our mines, mills, and processing plants, the loss of mine manpower to plants other than those concerned with the mineral industry, and the drafting of our younger men into military service have created an acute situation in many places as to workers and production. This, in turn, has focused attention on the need for conserving manpower by conserving the health and life of our mining people. Health A world-wide tendency is noticeable in the mineral industry toward protecting the health of workmen,-particularly younger workers, as well as older workers who can continue to produce in many places where manpower is lacking. This matter was emphasized at the Geneva Labor Conference for Coal Mines at the Committee&apos;s fourth session, held in Geneva, Switzerland, May 7 through 19, 1951. Papers concerning the health of workers were presented at the annual meetings of the mining sections of the National Safety Council, the Coal Mine Inspectors&apos; Institute of America, the American Public Health Association, and other organizations. Safety Conferences Without exception, the attendance at mining-safety conferences in widely separated places throughout the country during the year was the largest to date. What is needed at the safety meetings throughout the country is more-widespread attendance by those who can sell the idea to the workers that they are the focal point in accident prevention and that safety is not going to be achieved alone or even in part by laws, decrees, or commands, but by quiet influence, unconscious suggestion, and personal&apos; guidance. If these are acquired by the workmen, a safe environment and ample, capable supervision supplied by management, accidents will be fewer and less severe. Many safety conferences attempt to develop the foregoing idea by enumerating and describing training programs for supervisors and workers alike. Nothing can replace a course in first aid for all persons employed at any mine or plant as an introductory and basic step to a successful safety program. Even in this, the shoe must fit the foot, rather than applying the order do this or else. In first-aid

Jan 1, 1952

By B. Van Voorhis

Successive changes have been made in stoping methods at the Magma mine. Factors that have made these changes advisable are: vein width, heavy and swelling wall rock, abnormal rock temperatures, ventilation, labor costs, timber costs, mining speed, and labor-saving mechanical developments. Additional localized conditions, such as low angle post-mineral faulting and selective mining, have also made changes necessary. A stoping method with enough flexibility to meet most of these conditions has been in use for the past ten years. The Magma Copper Co. was organized by the late William Boyce Thompson in 1910 and acquired by purchase and location several groups of contiguous claims, among them the Silver Queen property. The Hub and Irene claims acquired in this purchase cover the apex of the vein, and all stoping done up to 1920 was from these two claims

Aug 1, 1956