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By N. L. Ananthanarayanan, J. F. Libsch

A LITERATURE survey1-' of sintering metal pow-A ders and powder compacts indicates that studies have so far been confined primarily to the latter stages of sintering in relatively coarse powders. Presumably this is due to the difficult techniques associated with studies of the early stages of sintering. Recent experimental and theoretical investigationsL-" on the preparation and the magnetic properties of ultrafine ferromagnetic powders suggest the possi- bility of following the sintering process from a very much earlier stage than has previously been considered. It is now well-known that ferromagnetic powder particles which are below a critical size behave as single domains and exhibit permanent magnet qualities characterized by a very high coercive force. When the same particles are fully sintered, the coercive force decreases to very low values corresponding to those of the solid metal. Thus the coercive force appears as a sensitive parameter which may be measured to study the early stages of sintering. To determine the feasibility of this technique, experi-

Jan 1, 1954

The American Federation of Labor adopted 'the following resolution at its Atlantic City convention: "WHEREAS, scientific research and the technical application of results of research from a fundamental basis upon which the development of our industries, manufacturing, agriculture, mining, and others must rest; and WHEREAS, the productivity of industry is greatly increased by the technical application of the results of scientific research in physics, chemistry, biology; and geology, in engineering and "agriculture, and related sciences; and the health and well-being not only of the workers but, of the whole population as well, are dependent upon advances in medicine and sanitation; so that the value of scientific advancement to the welfare of the nation is many times greater than the cost of the necessary research; and WHEREAS, the increased productivity of industry resulting from scientific research is a most potent factor in the ever-increasing struggle of the workers to raise their, standards of living, and the importance of this factor must steadily increase since there is a limit beyond which the average standard of living of the whole population cannot progress by the usual methods of re-adjustment, which limit can only be raised by research and the utilization of the results of research in industry;. and

Jan 8, 1919

By S. C. Libby

Physical degradation of calcined bauxite is related to the presence of goethite in the raw bauxite and to the development of secondary gibbsite. Goethite in the bauxite matrix will shrink and decrepitate during calcining, leaving a friable matrix and allowing disaggregation of the calcined bauxite during transport and handling. A matrix consisting of cryptocrystalline gibbsite alone or mixed with hematite will not shrink during calcination, yielding a calcine with high abrasion resistance. The development of secondary gibbsite between coarse gibbsite crystals also reduces degradation of the calcine by reducing the amount of disruption between grains resulting from differential thermal expansion.

Jan 1, 1981

Jan 1, 1950

Jan 1, 1952

By R. Neilson M. E. Clark

(with map on plate I.) THE coal-beds of Canyon City are situated six miles below the town, upon the Arkansas River. At this point the Rocky Mountains have thrown out from their main ridge two spurs. The one to the north, containing Pike's Peak and Cheyenne Mountain, is known as part of the "Rim Range;" the one to the west and south is known as the `1 Green¬horn Range." Against these syenitic mountains, the later rocks are piled and uplifted; at right angles to the direction of this main uplift is the axis of a lesser plication. On the north, west, and south, the pitch is steep, gradually flattening as it approaches the centre of the basin and rising again to the east at a pitch of about 5°, thus forming a perfect basin, the centre of which is only three miles east of the base of the Greenhorn Range.

Jan 1, 1873

By W. F. Burns

(Butte Meeting, August, 1913.) ATTEMPTS were made in 1908, at the Great Falls Works, to produce ingots direct from the Butte precipitate by smelting- the material in a reverberatory refining furnace. The ingots produced in this manner averaged 99.4 per cent. of copper and 0.40 per cent. of arsenic and antimony. The copper content being considered too low, it was decided to cast the copper into anodes and to treat the anodes in the electrolytic plant. No.1 Furnace, in which the precipitate was treated, was a regular cathode refining furnace previously employed in making wire bar, cake, and ingot from electrolytic cathodes. The hearth of the furnace was 24 by 12 ft., having a capacity of 100,000 lb. of cathodes. The furnace was coal fired, and the copper was dipped by means of trolley ladles.

Jan 7, 1913

By W. V. Vietti

Actual field data from several wells are used to illustrate the application of the method of determining the average density of the fluid column in a flowing oil well in the Yates field, Pecos County, Texas. The depths of the wells in the Yates field vary from 900 to 1700 ft., depending on surface elevation and the location of the wells on structure. Production rates over 8000 bbl. per hour have been determined and many wells are capable of producing 2000 bbl. hourly. Gas-oil ratios are usually below 400 cu. ft. per barrel, but a few wells high on structure have produced over 3000 cu. ft. per barrel. Incidentally, tubing wells has cut these high ratios to as low as 400 cu. ft.' By common agreement of the operators all wells making ratios over 400 cu. ft. will be tubed. Daily production of the field is prorated to 110,000 bbl. from an open-flow potential of 5,000,000 bbl. based on hourly open-flow gages.

Jan 1, 1931

By William Kent

During the discussions at the Philadelphia meeting in February last;) several speakers expressed their doubts of the general accuracy of chemical analyses of steel made by "iron works chemists," and especially of determinations of manganese. Since the meeting, the discussion of the " practical value of chemical analyses" has been continued at some length in 'the columns of the Iron Age.

Jan 1, 1882

By S. J. Mitchell

An analysis of bolting reinforcement of several large [approximately 18 m (60 ft) cube] pillars was performed. The many overcoring stress profiles in pillars at the mine were used to produce generalized stress distributions at various stages in pre- and post-failure. A complete stress-deformation curve was estimated from this data. The effect of pillar bolting on the load-deformation behavior was extrapolated from the observed unbolted behavior. Bolting can increase pillar strength by up to 10 percent. The effect of bolting on general mine stability was examined with a short computer analysis. The computer model was calibrated against measurements performed at the mine, and produced good agreement between measured and modeled stresses. The analysis indicated that bolting increases the bolted pillar safety factors in the event of additional pillar failure by a small amount (approximately 5 percent). Progressive pillar failure is unlikely, because arching transfers most load from yielding pillars to large unmined abutments rather than to the smaller panel pillars.

Jan 1, 1984

By T. V. Falkie, Robert Stefanko

Coal Mine Health and Safety Act in December 1969, the most comprehensive law in the history of the coal mining industry went into effect. Hardly anyone will quarrel with the philosophy that all miners in the United States should be afforded equal protection under the law irrespective of the state in which they reside. Furthermore, it appears contrary to any sound judgment that a competitive advantage should appear to accrue to a mine operator because his operations are located in a state with less stringent (and costly) health and safety laws Yet it is recognized that the quality of state mine laws and inspection agencies has been extremely variable. Why, then, should there be such resentments over the passage of the Act? The Act was written In the highly emotionally charged atmosphere following the Consol No. 9 disaster: the technical expertise within the industry was discredited and largely ignored; and those directly involved in the writing of the Act were non- technical and largely nonmining people. The result was that the law incorporated certain requirements that were impossible to meet (automatic brakes are the classical example) and certain parts that were too ambiguous and consequently open to interpretation.

Jan 1, 1971

By R. S. Shoemaker, F. W. McQuiston

CAMPBELL RED LAKE MINES Balmertown, Ontario 1974 Operating Data MINE LOCATION: Balmertown, in Red Lake mining area of Ontario TYPE OF MINE: Underground mine developed by vertical shaft to 4300 feet. Mining active above 3000 ft depth. ORE DESCRIPTION: Gold and minor silver.. Sulfur content about 1.3%. Ar senopyrite , pyrite, pyrrhotite, and stibnite. CAPACITY IN TONS124 HRS: 825 ASSAY: 0.66 oz Au per ton heads MILL PROCESS: Amalgamation, flotation, roasting of concentrate and separate treatment of calcines and flotation tails by cyanide. PLANT BUILDING: Mine mill and service facilities all housed in insulated and heated buildings POWER: Total consumption, mine and mill - 100 Kwh/T WASTE DISPOSAL: Impoundment of tailings. Arsenic to sealed underground storage EMPLOYEES: Total of 300 men on payroll. Housing in Balmertown and nearby communities.

Jan 1, 1975

By W. L. Korbee, P. Hazebroek, M. Prats, E. E. Allen, C. A. 225-000-000-017 Verbraak, H. C. van Elst

In a recent paper,' one of us has presented some experimental evidence on the relationship between twinning and brittle fracture in steel. From metallographic examinations of brittle fracture it could be derived that mechanical twins and microcracks are formed already in front of a running brittle fracture. A tentative explanation based on the evaluation of the statistical distribution of mechanical twins vs various angles to the fracture was given in the above mentioned paper. It was suggested that these twins are caused by stress waves emitted by a running brittle fracture. With the aid of high-speed photography and the use of photo-stress sheet we are now able to study in more detail the propagation of a brittle fracture and the emittance of stress waves connected with fracture. A typical example is given in Fig. 1. In this figure a running brittle fracture in an ordinary Thomas steel is shown. The experiment was performed on a Robertson apparatus and the stress waves caused by the fracture were made visible with photo-stress

Jan 1, 1962

By William Kent

DURING the discussions at the Philadelphia meeting in February last, † several speakers expressed their doubts of the general accuracy of chemical analyses of steel made by "iron works chemists," and especially of determinations of manganese. Since the meeting,. the discussion of the "practical value of chemical analyses" has been continued at some length in the columns of the Iron Age. †Transactions, vol. ix, p. 529.

Jan 1, 1882

It is well to bring before you again the chief purpose of the National Research Council and of this its Division of Engineering, to stimulate others to make researches rather than to make them ourselves, because a given amount of our energy spent in inciting others will accomplish far more than if applied in executing them ourselves. This is because there are scattered through the numberless governmental, educational, and industrial laboratories of the country a very great number of investigators not only capable of being stimulated, but willing to aid in cooperative broadly planned research rather than to follow the haphazard methods of the past. Taken collectively, these laboratories and their personnel can produce an annual crop of knowledge the value of which is of the order rather of billions than of millions of dollars. I invite you to regard this potential product as a crop, to be planned, fertilized, harvested, and distributed with the sane order of statesmanship, the same breadth of view, with which we treat any other great human product or achievement, whether agricultural, industrial, or transportational.

Jan 1, 1919

By L. R. Flint, W. L. Freyberger, W. J. Howarth

W. L. Freyberger (Director, Institute of Mineral Research, Michigan Technological University, Houghton, Mich.)-The authors are to be complimented on their theoretical analysis of a column flotation process, and the comment I wish to make is not related to that analysis, but to the use of the word "countercurrent" to describe that process. Strictly speaking, the process the authors have described is countercurrent only in the sense of particle-bubble contact. That is, as solid particles and air bubbles pass through the column, the leanest flotation feed (the tailing) comes in contact with the greatest concentration of mineral-free bubbles. However, air bubbles alone do not comprise the complete extracting phase in a flotation system. A second component of this extracting phase is the collector, which is really the extractant inducing transfer of mat-

Jan 1, 1972

By Maximo Monte-Flores

A PERUSAL of the most recent literature on the subject of hydrocarbons reveals that one point seems, to have been neglected by the various theories; that is, the influence of the bed-rock on the accumulation and distribution of oil and gas. This can be seen from the following statement of the principles of the most accepted theories. ANTICLINAL THEORY The anticlinal theory claims that the accumulation of the hydro-carbons in deposits of commercial importance was brought about by the gravity of the hydrocarbons, the oil and gas being forced to the top of the porous stratum by the difference of the specific gravity of the hydro-carbons and the water. The principal factors toward the accumulation were the general stratigraphic condition of the rocks, their texture and porosity, and their water content. This theory advocated the preexistence of structural deformation as the basis of the motion of gravity, thus implying the principle that the forces that have caused the deformation have had no influence on the movement of the hydrocarbons. STRUCTURAL THEORY According to the structural theory, the accumulation is due, chiefly, to the structure of the subsurface rocks and differs from the anticlinal theory, mainly, in not considering that the motion of the liquids have been caused by the force of gravity.

Jan 1, 1920

Tars Committee is the result of a desire of the authorities in charge of the publications of the four national engineering societies to co-operate in this matter. The members of the Committee are the following: Charles WarreN Hunt, Secretary of the American Society of Civil Engineers. D. S. Jacobus, Vice-President of the American Society of Mechanical Engineers. Joseph Struthers, Assistant Editor of the American Institute of Mining Engineers. CaRy T. Hutchinson, Chairman of The Editing Committee of the American Institute of Electrical Engineers. This Committee has held several meetings; it seemed advisable, at the outset, to limit its discussions closely to the general subject of abbreviations. Further, it seemed best to formulate a few general rules to be followed in making abbreviations, rather than to compile a list of forms to be recommended. The Committee decided to limit the subject more narrowly by considering only abbreviations to be used in the text, or general reading-matter, arid not those to be used in special matter,

Jan 1, 1905

By Gerald Schroeder

The flow of gases, particularly radon and methane, into the mine atmosphere is a problem traditionally controlled by ventilation-dilution techniques. More recently, a preventative approach has been to seal underground surfaces with a polymeric coating to act as a barrier against the influx of dangerous gases. H However, a study by the Israel Government Research Station indicates that unless the rock surface is perfectly sealed, much of the labor to reduce interstitial gas flow is lost to the effects of barometric "breathing" from the rock pores. Previous research has reported the increased frequency of coal mine explosions during periods of barometric pressure minima,1 and the phenomena has been explained through correlation of the observed increase in mine gas concentrations during periods of low barometric pressure with the connective flow of interstitial gases from rock pores into the arsine atmosphere when pressure was actually falling.234 While changes ill barometric pressure arc rapidly transmitted to the mine atmosphere, response in the rock interstices is sluggish, momentarily creating a pressure differential between the mine atmosphere and the interstitial gases. Responding to the pressure gradient, this interstitial gas flows until pressures are equalized.

Jan 6, 1977

ASIDE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has four awards it may make annually, as fol¬lows: the Robert W. Hunt Medal and Prize, the J. E. Johnson, Jr., Award, the James Douglas Medal, and the William Lawrence Saun¬ders Medal. ROBERT W. HUNT MEDAL AND PRIZE The partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules 1. The award shall consist of two prizes: first of a gold medal, second of a sum of money; a certificate to accompany each prize. The money prize shall not be awarded to a member over 40 years of age, but under unusual circum¬stances, both prizes may be allotted to one person provided that he is not over 40 years of age. In general it will be understood that the Committee shall award the money- prize to the younger men, rather than the medal.

Jan 1, 1923