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By Clarence Zener

THEORETICAL considerations by one of the authors have led1 to the prediction that the dynamic internal friction of annealed metals has a broad maximum at a certain grain size. This prediction they have veri-fied2 for alpha brass. In the present paper the theory is extended to include the precise manner in which the internal friction varies with grain size on either side of the maximum. New experimental data are pre¬sented to test this extended theory. The physical basis for the type of internal friction that is being investi-gated lies in the interplay between stress and temperature. Just as local fluctuations in temperature give rise to local fluctuations in stress, so like-wise fluctuations in stress give rise to fluctuations in temperature. But temperature gradients give rise to necessarily irreversible thermal cur-rents, and hence to internal friction. The theory for this type of internal friction has been developed quantitatively,3 and has been experimentally verified,4,5 for the particularly simple case of the transverse thermal cur-rents accompanying transverse vibrations. Of more fundamental impor-tance are the intercrystalline thermal currents accompanying all types of vibration. The variation in stress across grain boundaries arises from the elastic anisotropy and at least partial random orientation of the individual crystallites. An exact quantitative treatment of the internal friction due to these thermal currents is of course out of the question. However, much information can be obtained from general arguments.1,6 Thus when the frequency of vibration f is low, or when the grain size d is small, adja-cent grains remain nearly in thermal equilibrium, and vibration proceeds isothermally with little internal friction. Again, when the frequency is high, or the grain size large, the heat flow per cycle is small, the vibration proceeds adiabatically with little internal friction. The internal friction will become a maximum in the transition region. The degree of adiabatic-

Jan 1, 1940

By George W. Riter

A distinguished engineer, the active head of a large mining company, has said that surveying attains the dignity of a profession only in the hands of a few men—the few who know how to keep notes that will be understood by even a novice without further word of explanation. Of all mine-records, survey notes are perhaps the most important. The maps made from them serve as a working-guide, and as framework for other data; and when, from any cause, access to underground workings is shut off, the surveyor's record often becomes invaluable. So seldom docs a surveyor have a chance to check underground surveys by making a closure, that he is compelled to rely on the precision of each step of his work for the accuracy of the final result. When data are fully recorded on the spot, the notes, even in the hands of second parties, become evidence of the care and precision with which the surveying was done. It is worth a great deal to be able to pick up the work of a former surveyor where it was left off, and to be able to carry it forward without rctracing from the beginning. The purpose of this paper is to describe the survey-note system of a mine now under my direction, in which underground surveys had to be relied upon entirely for the proper division of rich ore-bodies between neighbors, thereby placing a premium on accurate surveying and permanent records. In survey-work, it soon turns out that paper is the least item of expense, and that little is gained by trying to economize note-book space. For many purposes it is best to record notes on cards or loose-leaves, which may be left in the office at the end of the day's work, and need not be carried into the mine again, there to become smeared with grime and grease. With the loose-leaf or card system, all notes relating to the same local-

Jan 1, 1911

By Richard A. Arnold

The evolution of planning processes in the United States from the early 1900's is briefly examined. From one year operating budgets, planning processes have evolved into sophisticated analyses of alternative long-term future strategies and the management issues and practices which relate to their implementation. Increasing complexity within the business environment has led to numerous planning methodologies and extensive use of computers to analyze operating and financial information. All of these developments, however, have not supplanted the real need for decision-makers to continue to give important weight to the intuitive or soft data inputs into the planning process.

Jan 1, 1985

By G. Don Sullivan

Surface mine operators have organized a voluntary group known as the Mined-Land Conservation Conference for the specific purpose of developing and expanding reclamation programs on mined land. As a part of the Conference program, a Voluntary Industry Program was adopted and subscribed to by its membership. This program stated: "The basic approach to a sound conservation program is the restoration of mined land to its most practical and productive use within the shortest possible time . . . reclamation of mined lands, including planting to grasses or tress, should be done on a planned basis, under technical guidance by personnel trained in this field."

Jan 7, 1965

By Horace Pops, J. F. Libsch

THE discovery of SAP alloys (sintered aluminum powders) by lrmannl has stimulated investigations in other alloy systems.23 Not only do such alloys have good room-temperature properties, but they maintain high strength after prolonged service at elevated temperatures. In addition, they show high structural stability, including unusually high recrystallization temperatures. These characteristics are secured by dispersion hardening. For this investigation, Zn-ZnO alloys were selected. Practically, the fact that commercially pure zinc recrystallizes near room temperature prohibits strengthening and hardening by cold deformation and therefore limits the application of zinc where mechanical strength is important. Similarly, the poor

Jan 1, 1961

By A. K. Burton

This paper reviews transportation trends in large base metal open-pit mines in recent years. Particular attention is paid to the unprecedented increases in the cost of oil and its effect on operating costs. Fuel conservation and measures to improve trucking efficiency are considered. The paper also discusses viable alternatives for reducing or eliminating the use of trucks. Various advantages and disadvantages of using conveyors to transport shot rock from the mine are reviewed. The paper concludes with some observations on current policies and trends primarily aimed at mitigating the high cost of energy.

Jan 1, 1983

By R. A. Wyman

KYANITE schists in the Sudbury area have been generally described by Haw,1 who has also given particular information on preliminary treatment of three large samples from Dryden township, Ontario.2 Kyanite, garnet, biotite, quartz, and feldspar comprise the main ingredients of this ore. Kyanite is the valuable mineral. About 5 ½ tons of -35 +200 mesh product, made by dry rod milling, screening, and separation on the Exolon magnetic separator, were available for treatment by flotation. Magnetic separation had effectively reduced garnet and biotite so that flotation feed consisted essentially of kyanite, quartz, and feldspar, the kyanite content averaging 32 pct and representing about 86 pct of the kyanite in the original ore.

Jan 1, 1958

THE Howe Memorial Lecture, in memory of Henry Marion Howe, Past President of the Institute, was authorized in April, 1923, as an annual address to be delivered by invitation under the auspices of the Institute by an individual of recognized and outstanding attainment in the science and practice of iron and steel metallurgy or metallography, chosen by the Board of Directors upon recommendation of the Iron and Steel Division The following were the Howe lectures and lecturers for the years indicated 1924 What is Steel? By Albert Sauveur 1925 Austenite and Austenitic Steels By John A Mathews 1926 Twenty-five Years of Metallography By William Campbell

Jan 1, 1952

By G. H. Clamer

Page Bronze Bearing Metals. By G. H. Clamer............... 162 Pennsylvania Railroad Anti-friction and Bell Metals. By F. M. Waring .. 166 The Tin-plate Industry. By D. M. BUck. Discussed by G. H. ClameR, J. W. RICHARDS............................ 168 The Aluminum Bronze Industry. By W. M. Corse............ 171 Bronzes, Bearing Metals, and Solders. By G. K. BURgess and R. W. Woodward. Discussed by G. H. Clamer, R. T. Roberts......... 175 Babbitts and Solder. By G. W. Thompson................ 184 The Cadmium Supply of the United States. By C. E. Siebenthal. Discussed by M. L. Lissberger, C. W. Hill, F. F. ColcoRd.......... 185 Solder, Its Use and Abuse. By M. L. LissbergeR............ 192 Bronze Bearing Metals G. H. ClameR,* Philadelphia, Pa.—Unfortunately, prior to the war no serious attention was given to the conservation of tin, notwithstanding that this country is practically dependent upon outside sources for its entire tin supply. Tin is of vital importance in many industries, but it is surprising how many and how excellent are its substitutes when we become acquainted with them. Tin has always been a relatively high-priced metal, and it is part of the human attitude to associate high prices with high standards; it is not until the price of a commodity becomes well-nigh prohibitive that we hunt for substitutes, because the idea of substitution seems always to involve an assumption that the substitute must necessarily be inferior. The history of the development of bearing bronzes is a striking example of this policy. In the early days, copper-tin alloys were almost universally used, the idea then being prevalent, which is still held by many, that a bearing to resist wear must be hard, and the harder the better. The favorite bronze bearing contained 90 per cent. copper and 10 per cent. tin; frequently, in service which was considered severe, even higher proportions of tin were used. Such hard alloys have great resistance to compression, but as a rule they had a very wide factor of safety in this

Jan 1, 1919

By John Birkinbine

An item of considerable importance to the producers of pig-iron is the disposition of the slag or cinder from the blast-furnace; and various plans have been adopted at different works to care for the rapid accumulation of this generally waste material. The charge per ton of iron made which must be allowed for the care of cinder is sufficient in times of business depression to give plants having facilities for disposing of their slags an advantage over others less favorably arranged, and to allow iron to be produced profitably in the one case and prevent a profit in the other. The varied methods employed and the means of conveyance utilized need not be detailed. It is sufficient to say that the large outputs of American blast-furnaces, and consequent rapidly augmenting dump-piles, have brought into general favor the use of cars carrying the slag in a liquid condition. The advantages of this method are the prompt removal of the slag, the reduced space occupied by the dump-piles, and the facility of converting the slag into such forms for use as may be desired. The progress in iron-manufactlire is also marked by a more general adoption of methods by which molten metal is carried in vessels away from the point of its production; and, anticipating the prospective advance in pig-iron manufacture, it does not seem unreasonable to prophesy the early abolition of casting-houses at blastfurnaces, particularly where several are grouped together; or the casting of steel ingots away from the converters or furnaces. In some large blast-furnace plants, the iron is carried molten from the blast-furnaces to the converters or other furnaces. Even where it is cast into pigs, casting-sheds removed from the immediate vicinity of the furnace-stack would, perhaps, be superior to casting in beds in front of the furnaces. The idea of casting-sheds appears to present the following advantages : 1st. The equipment of boilers, hot-ovens, and blowing-machinery could be closely grouped around the blast-furnace stacks, permitting

Jan 1, 1887

All indications point to a most interesting and successful meeting in Chicago on Sept. 22-27. Already 140 papers have been submitted to the Committee on Papers and Publications. Of this number 46 deal with pyrometry, 17 with iron and steel, and 24 with coal. The tentative program is as follows: PROGRAM OF CHICAGO MEETING Monday. Morning-Registration. Oil. Afternoon-Technical Sessions. Coal. Milling, Industrial, and Iron Geology. Evening-Smoker. Tuesday.- Morning and Afternoon-Excursion by boat to Gary and trip through United States Steel Co.'s plant. Technical session on Ferrous Metallurgy on the boat, return trip Evening-Technical Session. Wednesday. Morning-Technical Sessions {Ferrous Metallurgy. Mining. Afternoon-Technical Sessions {Ferrous Metallurgy. Non-ferrous Metallurgy... Evening-Banquet, Congress Hotel.

Jan 7, 1919

By Robert E. Goodwin

There are four main requirements to be considered in selecting a wire rope that will provide the best service. A proper choice is made by correctly estimating the relative importance of each of these requirements and choosing a rope with qualities that will best enable it to withstand the combination of destructive forces expected under continued service. A Good Rope Choice Matches Strength with Stress A wire rope should be (1) strong enough to sup- port the maximum load anticipated with a proper safety factor, (2) able to withstand bending and to resist bending fatigue without failure of the wires, (3) able to withstand surface abuse such as abrasion, pounding, and wire scrubbing, and (4) able to take abuse such as crushing and distortion.

Jan 5, 1969

By M. T. McDonough

THE data relative to the effect of metal depth on slag volume was obtained from the operation on two acid electric furnaces in which heats of various sizes were produced. The furnaces used were of 3 and 5-ton rated capacity; the heats investigated ranged from 6 to 8 tons. Heats of 7 and 8 tons were made in the larger furnace; heats of 6 tons in the smaller one. Bath depths and diameters were measured on the furnaces when cold and each is accurate to one inch. Both the metal charge and the slag were weighed on a track scale accurate to ± 25 lb. All other components added to the furnace were weighed on a wheelbarrow scale accurate to ±5 lb.

Jan 1, 1947

By D. M. McFarland

A FEW years ago a novel electric detonator known as the split-second or millisecond delay electric blasting cap was introduced for use in quarry blasting. Regular electric blasting caps fired in series may be depended upon to fire within a millisecond or so from the first to the last in a series. Regular delay electric blasting caps are provided that fire one period after the other period in intervals of 1/2 to possibly 1 l/2 sec. Most split-second or millisecond delays are designed to fire one period after the other period in possibly 25 to 50 millisecond intervals. The ear is not capable of detecting time intervals of this magnitude.

Jan 11, 1950

By William J. Millard

The Island of Trinidad has much the same geological history as the continent of South America. There are present in this area Cretaceous, Tertiary and Quaternary rocks, which were deposited in a basin covering eastern Venezuela and Trinidad, very much as rocks of the same age were deposited in the Maracaibo Basin in western Venezuela. Along the north coast there are metamorphosed and semimetamorphosed Cretaceous rocks which are found as semicrystalline limestone, schists and quartzites, etc. Both the Cretaceous and Tertiary rocks are petroliferous and are responsible for the production of oil in Trinidad and eastern Venezuela. The geological column in the oil-bearing region of Trinidad is shown below.

Jan 1, 1931

By Walter F. Pond, Kendall E. Born

Production of crude oil in Tennessee during 1935 approximated 20,000 bbl., an increase of about 5000 bbl. over 1934. The total production for the state is an estimate, since the only definite figures available are those for Scott and Morgan counties, where 12,377 bbl. were marketed during 1935, an increase of 4305 bbl. over the preceding year. The oil fields of Scott and Morgan counties are near the eastern margin of the Cumberland Plateau where Pennsylvanian sediments rest uncon-formably upon the Mississippian. Near Glenmary, in Scott County, the production is from the middle Mississippian, probably near the top of the St. Louis limestone. Accumulation is due to a low, east-west anticline which has been cut by a fault. This field is now 20 years old and only a few wells are pumped at present. Oil was Struck along Boone Camp Creek in Morgan County in 1924 and there has been small production since that time. The oil comes from the middle of the Fort Payne formation of lower Mississippian age at a depth of 1400 ft. Geologic work in the area has shown that a terrace and porosity conditions in the Fort Payne formation account for the accumulation. The production figures on a number of small producing wells in Clay and Overton counties are not available. As pointed out by Glenn1, the installation of small local skimming or topping plants in the fields has curtailed the shipment of crude oil out of the state and as a result it has been impossible to secure accurate production figures in these counties. The operators, in most cases, are reluctant to give information, and there is no state law requiring them to do so. Based upon information available to the writers, it is believed that between 7000 and 8000 bbl. is a fair estimate of the production in Clay and Overton counties during 1935. More than 500 wells have been drilled in Clay County, the majority of which were drilled east of Cumberland River. Some eight small oil fields have been developed in the county within the past 12 years, a

Jan 1, 1936

By Kendall E. Born, Walter F. Pond

Production of crude oil in Tennessee during 1935 approximated 20,000 bbl., an increase of about 5000 bbl. over 1934. The total production for the state is an estimate, since the only definite figures available are those for Scott and Morgan counties, where 12,377 bbl. were marketed during 1935, an increase of 4305 bbl. over the preceding year. The oil fields of Scott and Morgan counties are near the eastern margin of the Cumberland Plateau where Pennsylvanian sediments rest uncon-formably upon the Mississippian. Near Glenmary, in Scott County, the production is from the middle Mississippian, probably near the top of the St. Louis limestone. Accumulation is due to a low, east-west anticline which has been cut by a fault. This field is now 20 years old and only a few wells are pumped at present. Oil was Struck along Boone Camp Creek in Morgan County in 1924 and there has been small production since that time. The oil comes from the middle of the Fort Payne formation of lower Mississippian age at a depth of 1400 ft. Geologic work in the area has shown that a terrace and porosity conditions in the Fort Payne formation account for the accumulation. The production figures on a number of small producing wells in Clay and Overton counties are not available. As pointed out by Glenn1, the installation of small local skimming or topping plants in the fields has curtailed the shipment of crude oil out of the state and as a result it has been impossible to secure accurate production figures in these counties. The operators, in most cases, are reluctant to give information, and there is no state law requiring them to do so. Based upon information available to the writers, it is believed that between 7000 and 8000 bbl. is a fair estimate of the production in Clay and Overton counties during 1935. More than 500 wells have been drilled in Clay County, the majority of which were drilled east of Cumberland River. Some eight small oil fields have been developed in the county within the past 12 years, a

Jan 1, 1936

By J. Ostachowicz, B. Holynska, M. Lankosz

The paper presents an analyzer and the method for the continuous determination of weight percentage of ore grains with diameter smaller than 75 µm in mineral slurries. The method is based upon the measurement of characteristic x-rays of copper excited by primary radiation of two different energies 16.5 keV and 60 keV from Pu238 and Am241 sources respectively. Additionally the backscattered primary radiation is measured in order to correct the variations of the solids content in the slurry. Since the particle size distribution of slurry can be described by the Rosin-Rammler formula, some calculations have been carried out in order to evaluate the influence of distribution parameters upon the results of the measurements of weight percentage U75 of particles smaller than 75 µm. The influence of solids content and of the copper concentration variation on the results has been also evaluated.1 It resulted from the calculations that the ratio rl/rz, where rl and r2 are the relative intensities of copper characteristic x-rays excited with 16.5 keV and 60 keV photons respectively does not depend on the copper content within the range 1 % to 4% of copper and is slightly dependent on the solids weight fraction and its chemical composition. The change of the dispersion parameter of the Rosin- Rammler distribution from 0.5 to 0.9 results in a change of value of U75 of approximately 3.0%. The results of calculations have been confirmed by the results of laboratory experiments. Therefore, a prototype of industrial analyzer for continuous determination of weight percentage of particles smaller than 75 µm has been designed and made. Its schematic drawing is shown in [Fig. 1]. Slurry is flowing down through steel flow-cell of the length equal to approx. 2 m. In the center, two XRF measuring heads (1) and (2) are located. Each of the heads comprises a rigid waterproof cover (3) with the mylar window (4), in which a proportional counter of resolution 15% for 6.4 keV is mounted with a preamplifier (5). The low- energy isotope source (6) is centrally located above the detector

Jan 1, 1980

By John Howe Hall

The recently announced run of three years, nine months and eleven days made by a crucible steel melting furnace of the Columbia Tool Steel Co., which is claimed as a world's record, brings forcibly to our attention the great improvements that have been made in the design, construction and operation of the Siemens regenerative crucible melting furnace since its introduction in this country. Credit for this advance should be given to the furnace designer, the manufacturer of refractories, and the operators, of the furnaces, whose persistent efforts and intelligent co-operation in attacking the problem have resulted so satisfactorily. There are three factors that determine the life of a crucible furnace, or any other furnace for that matter: Design, nature of refractories, and conditions of operation (including the nature of steel melted); and to some extent these factors are interdependent. Thus, for instance, if a crucible furnace is to be operated single turn and allowed to cool off considerably at night, in order to save fuel, the use of clay-brick melting holes may be advisable, since silica brick is not well adapted to endure repeated heating and cooling. But the total life of a clay-brick melting hole is necessarily short. Again, if local conditions such as danger of flood make necessary the building of the furnace largely above ground, so that the radiation of heat is promoted, the cooling down of the furnace over the week ends, when no steel is melted, will be considerable—and the contraction of the furnace that results tends to wrack it to pieces. The character of the metal being melted affects the life of the furnace to a great extent. Low-carbon steels and steels made from iron and charcoal require higher temperatures and much longer melting time than high-carbon steel or steel made largely from scrap; the life of the furnace will be shorter, and the number of heats melted will be much less, when such materials are melted. The figures available, showing the life of furnaces, are for this reason especially not strictly comparative, since the variations in the steel melted undoubtedly affect the life to a greater or less extent. Probably, however, the method of handling is as important a factor

Jan 1, 1914

By Garfield Schnee

MACHINERY has not taken the place of manual labor in steep pitch coal in the anthracite field and there is a shortage of miners experienced in this type of work. To overcome these difficulties several coal companies have resorted to different types of mining such as the diamond or zig-zag method, the slant method, long hole drilling, and several other variations. For the past 5 years the diamond shape method has been used extensively in the heavy pitching beds of both the Knickerbocker and Yatesville basins at Knickerbocker colliery of the Philadelphia & Reading Coal & Iron Co.

Jan 10, 1950