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By W. J. Putnam, H. F. Moore

THIS paper gives a preliminary summary of results of tests on the resistance to fatigue under reversed stresses of steel subjected to cold-working and of tests to determine the effect of rest on the endurance of steel under reversed stresses. The tests of cold-worked steel were undertaken as part of an investigation by the National Research Council Committee on Fatigue Phenomena of Metals and were made by Mr. Moore; the tests to determine the effect of rest are part of an investigation now being made by Mr. Putnam. Both series of tests were made in the Materials Testing Laboratory of the University of Illinois. The preliminary results of these tests are reported now because it is believed that test data on fatigue strength should be available at the earliest possible moment; however, it should be clearly kept in mind that this paper gives preliminary results and is intended to encourage discussion rather than to give final conclusions. Before giving the data of the tests, the writers will explain the term "fatigue strength" as used in this paper and will discuss briefly the method used in interpreting the test data of repeated-stress tests. " The term fatigue strength, as applied to a material, may be defined as that maximum fiber stress that will cause fracture of the material after the repetition of any given number of cycles of stress, each cycle involving the variation of stress from a minimum to the above maximum. The fatigue strength, then, varies with the number, of repetitions occurr,ing in the lifetime of a structural or machine member and with the range of stress for each cycle of stress. The fatigue strength will be lower for a member in which the stress is completely reversed than for one in which the stress varies from zero to a maximum. In interpreting test data from fatigue tests under reversed stress, the stresses and corresponding numbers of repetitions required for failure are plotted on logarithmic cross-section paper. In 1910, Professor

Jan 1, 1920

By Edward Keller

About a dozen years ago the art of bessemerizing copper- * matte, brought to these shores from France, was first established at the smelter, in Butte, Montana, of the Parrot Silver and Copper Company, which had bought the process from Mr. Manhks, the inventor. Through the efforts of Mr. J. E. Gaylord, general manager, and Mr. A. J. Schumacher, snperintendent,, assisted by an able staff, the new method rapidly underwent, at the Parrot establishment, an evolution towards higher perfedion, and within a few years its success and its advantages were so marked that all the great works in the west followed in the footsteps of this pioneer. The converter-process has now practically superseded the reverberatory-process in this country. The latter will undoubtedly, in a not very distant future, be relegated to metallurgical history. The writer has availed himself of what was perhaps the last chance to make comparisons of the two methods, working practically on the same material on an extensive scale, the reverberatory process being that of the Baltimore Copper Smelting and Rolling Company,* while the converter-process is that of the Anaconda Copper Company—both using the matte from the latter company's works in Anaconda, Montana. For the greater portion of the material considered in this paper, the writer is indebted to the two companies. In order to understand the difference of behavior of the several elements, and the difference of the copper produced in the two processes, it is best to study and follow those elements

Jan 1, 1899

CHARLES CATLETT, Staunton, Va.-A great many important things have been said in an interesting way but the most startling, to me, is that for 25 years, the price has been in the neighborhood of $1.00, with a minimum of 86 cents and a maximum of about $1.25. It is evident that during all that time the price was inadequate. The amount paid to be divided between the land owner, the capitalist, and the laborer was too limited or too irregular to permit of a healthy condition; yet it is evident that the enormous industrial development of this country was fostered by this very cheap coal, probably the cheapest that has been provided in quantity in any country. I entered the coal business when the price was lowest and my interest and sympathy went out to the man who spent his days in the dirt and foul air of a mine and I was filled with schemes for helping. But at the end of the year, after exercising every economy and in blissful ignorance of proper depreciation and obsolescence, there was still only a profit of 1 cent per long ton for what I think is one of the best coals in the world, the best grade of New River coal. We are now paying a great deal more than we did a few years ago and probably will continue to pay more for some time; but any one who thinks we will not have low prices again is very young or very forgetful. Yet we must have larger profits if the industry is to be healthy, if the three parties to the production are to get adequate returns and be in shape to provide the improvements which will be needed to take the place of and supplement the man-power. This will come when the men are making so much money that the operator wants to replace the man by a machine, and when the operator is making so much money as to be in a shape to make the improvements. He will not put in machinery unless the machinery will save money. We have got to pay a higher prime cost for coal, but engineering skill will teach us how to handle it better and use it more economically, and the ultimate result ought to be of advantage to the public.

Jan 3, 1920

By Harlowe Hardinge, R. C. Ferguson

Laboratory and plant data covering 12 different operations show that lower than "standard" ball mill speeds increase grinding efficiency. In the case of high pulp-level mills, the gain is so great that the increase in capital cost of the larger lower speed mill will pay for itself in less than a year's time.

Jan 1, 1950

By E. H. Griswold, C. E. Beecher

DURING 1931 the petroleum industry has faced the most hazardous periods of its existence, caused by large potentials, overproduction, and demoralized markets. Two state governors actually resorted to the use of the militia in an effort to restore a semi-stabilized condition within the industry, to prevent waste of the states' natural resources, and to restore prices to a level that would yield the states a reasonable tax revenue. These conditions have made it necessary to put into effect most. stringent economies and have produced a spirit of cooperation between companies to an extent that never before existed. The necessity for unified action on such matters as proration and the advantages to be gained by unit operation are being realized by the oil industry as a whole. Fewer wells have been drilled and wildcat operations almost eliminated: development and operation costs have been greatly reduced and more attention is being paid to efficient recovery methods. The net work of oil pipe- lines has grown rapidly especially in the area of East Texas. The construction and operation of natural gas and gasoline pipelines into areas far distant from the source of supply has been one of the outstanding accomplishments. Refining efficiency has continued to increase and the public is being supplied with a better grade of gasoline at a lower price. The unreasonable tax which state politicians have succeeded in placing on gasoline has encouraged tax evasion and unfair competition by un- scrupulous dealers and has misled the public as to the true price of gasoline.

Jan 1, 1932

The following list comprises the names of those persons who became. members during the period Oct. 10, 1919, to Nov. 10, 1919. ABELL, 0. J., Pres. & Treas., Abell-Howe Co., 332 South Michigan Ave.; Chicago, Ill. ADAMI, ARTHUR E., Asst. Prof. of Min. Engrg., Montana State School of Mines,Butte, Mont. BASSETT, R. H Chief Engr., Hanna Ore Min. Co., Hibbing, Minn. BOZA, HECTOR J., Cons. Engr., Boza Aizcorbe Hermanos, Box 106, Lima, Peru. BROWN, HAROLD P., Cons. Concrete Engr 120 Liberty St., New York, N. Y. BUCHANAN, W. A Mgr., Meteor Mine, Slocan City, B. C., Canada. CAMERON, JAMES A Supt., Ellsworth Collieries Co., Ellsworth Pa. CARPENTER, CRANSTON HOWE, Electro-Met. Engr., General Engrg. Division, Westinghouse Electric & Mfg. Co., East Pittsburgh, Pa. CASTLETON, GEORGE T Assayer, Custom Office, Box 122, Eureka, Utah. CHAFFIN, C. E., Eastern Mgr., General Engineering Co., 120 Broadway, New York-, N. Y. CLARK, WALTER R., Wks. Mgr., Bridgeport Brass Co., 1875 Park Ave., Bridgeport, Conn. CLARKE, ERNEST E., Min. Engr., Vinegar Hill Zinc Co., 419 S. Court St., Platteville, Wis. COOLIDGE, E. B., Mgr., Spotted Horse Mine, St. Paul Montana Min. Co., Maiden, Mont. CORTELYOU, ARTHUR P., Resident Mgr., Potrero Min Co. Mocorito, Sinaloa, Mexico. COTTINGHAM, KENNETH, Pet. Engr., Halter & Robitaille Delmonico Bldg.,Fifth Ave. & 44th St., New York, N. Y. CREW, J. A Mgr., Research Dept., Pittsburgh Steel Co., Monessen, Pa. CUMMINGS, LISTER M., Efficiency Engr., Copper Queen Branch, Phelps-Dodge Corpn., Box 1539, Bisbee, Ariz. DANFORTH, GEORGE L., JR., Asst. Gen'l Supt., Illinois Steel Co., South Works, South Chicago, Ill.

Jan 12, 1919

By Å. Sterten, R. Tunold, J. Brun, K. Dalatun

c axis compression behavior of beryllium single crystals at three purity levels under hydrostatic pressures up to 27 kbars was determined. Extensive non-basal slip, observed by two-surface trace analysis and transmission electron microscopy, occurred under a hydrostatic pressure of about 12 kbars (175 ksi) for the high-purity (twelve-zone pass) material and at about 19 kbar (275 ksi) for the lower-purity (zone-leveled) material. Prismatic loops with a (c + a) Burgers vector were observed in association with second-phase parti- A principal factor limiting the use of beryllium is its brittle behavior when tested at the usual strain rates (E = 10-4 sec- 1) at temperatures below about 200°C and under impact conditions at temperatures in excess of 200°C. It has been proposed' that the brittle-ness of beryllium is associated with the lack of a sufficient number of independent slip modes and the absence of a slip mode with a Burgers vector out of the basal plane [presumably (c + a) pyramidal slip mode] and to the ease with which beryllium cleaves on the basal and second-order prism planes. The absence of pyramidal slip has been attributed to a high Peierls-Nabarro stress associated with the motion of dislocations with a (c + a) vector and the ease with which cleavage occurs on the basal and second-order prism planes. The experimental evidence in support of the proposed explanation for the brittleness of beryllium is far from complete; for example, that the ductile-to-brittle transition in polycrystalline beryllium is associated with the operation of profuse (C + a) slip has not been unequivocally established. The occurrence of (c + a) slip ({1122}(1123)) has been experimentally established2-5 under conditions where basal and prism cleavage are restricted in a c axis compression test. In these investigations (C +a) slip was found in high-purity beryllium single crystals tested in c axis compression* at 200°C and in Be-4.4 pct Cu and Be-5.2 pct cles in the lower-purity materials tested. The loops were related to surface "extrusions" observed on many of these same specimens. Nonbasal dislocations operating on (1122) planes with a (c + a) Burgers vector were observed. The presence of c and a dislocations together with (c + a) dislocations suggests that the (c + a) dislocations dissociate presumably on unloading or after failure of the test crystals to c and a dislocations. terial, (c + a) slip has only been observed near the the fracture4 surface in room-temperature c axis compression tests. Fracture in these tests occurs without measurable plastic flow, as determined with a strain sensitivity of 10"6. Since it has been shown for many metals that the application of hydrostatic pressure suppresses fracture,?-' it was felt that studying the behavior of unalloyed beryllium single crystals stressed in c axis compression under a hydrostatic pressure would reveal whether (c + a) can occur if fracture was prevented, and that it might elucidate the role of (c + a) slip in the ductile to brittle transition. Evidence that (C + a) slip is associated with increased ductility in a high-pressure environment has been found in stress-strain tests on poly crystalline beryllium.10 The present paper describes a study on the influence of a hydrostatic pressure environment on the occurrence of (c + a) slip in beryllium single crystals. Material of two purity levels was tested in c axis compression over the pressure range ambient to about 27.5 kbars.* 1) MATERIAL PREPARATION AND CHARACTERIZATION Two lots of low-purity single-crystal beryllium were used. The first lot was "ingot secondary refined grade" and designated lot A. The second lot (lot B) was produced by a two floating zone pass zone-leveling operation in an argon-filled sealed quartz apparatus on a 1-in.-diam by 12-in.-long bar of Pechiney secondary refined-grade vacuum-cast and hot-extruded material. The high-purity material (lot C) was made by traversing twelve floating zone passes through a similar bar of Pechiney secondary refined-grade vacuum-cast and hot-extruded material. In a series of spark cutting and lapping procedures,11 single-. crystal specimens some 0.12 in. sq by 0.30 in. high were made with the sides Parallel to the first- and second-order prism planes and the basal plane within 3' of arc of the top and bottom surfaces of the specimen. Such an accurate orientation is necessary because of the large difference in resolved shear stress

Jan 1, 1970

By E. A. Gulbransen, K. F. Andrew

Thermodynamic information on the solubility of hydrogen in exothermic metals is limited. Thus, the overall solubility decreased as the temperature rose, which suggests the heat of solution of hydrogen in the metal is negative; yet the terminal solubility in the metal phase increased, which suggests an endothermic reaction. A thermodynamic analysis, therefore, was made of the several equilibria involved when hydrogen dissolved in the metal. Equations were derived expressing the solubility, terminal solubility, and decomposition pressures of hydrogen in terms of the heat, entropy, and free energy of solution of hydrogen in the given phase. The relations between the thermodynamic functions for the a-zirconium and 8-hydride phase were developed. The thermodynamic quantities were determined experimentally by the measurement of the decomposition pressures over a broad composition and temperature range. Two new methods of analyzing the experimental data were developed for determination of the terminal solubility. STUDIES', ' of the impact strength of zirconium at room temperature indicated that small quantities of hydrogen, of the order of 10 parts per million, embrittles the metal. Micrographic' and X-ray diffraction' studies showed this embrittlement to result from the precipitation of a second phase upon slow cooling. These studies suggested that the terminal solubility of hydrogen in the metal phase increased with increase of temperature. This behavior appeared to contradict the effect of temperature on exothermic hydrogen occluders such as zirconium. For these metals, the solubility of hydrogen should decrease with increase of temperature. Before these facts could be understood, a thorough analysis of the several equilibria was essential. It was the purpose of this paper to consider the several equilibria involved when hydrogen was reacted with zirconium from both the theoretical and experimental points of view. Since the overall solubility of hydrogen in the metal has been considered by a number of workers, it was proposed to study the composition range 0 to 6 atomic pct H in detail. Literature Schwartz and Mallett' determined the terminal solubilities of hydrogen in the metallic phase from diffusion studies. They extrapolated concentration-penetration curves to the boundary between the solid solution phase and the hydride phase at the surface. Their results showed values of 2.6 atomic pct at 400°C and 5.2 atomic pct at 500°C. Extrapolations of the data to room temperature suggested very low values for the terminal solubilities. This study confirmed the hydrogen embrittlement results and indicated that the terminal solubilities increased as the temperature was raised. The solution of hydrogen in zirconium over the complete concentration range was studied by Hall, Martin, and Rees3 and by others. The results showed that hydrogen was absorbed up to a maximum composition of 66 atomic pct or ZrH This composition represented the t-hydride phase. The maximum amount of hydrogen absorbed increased with pressure and decreased with temperature. Due to this temperature behavior, zirconium was classed as an exothermic occluder." In 1930 Hägg studied the crystal structures of the Zr-H alloys over a broad composition range. Four hydride phases were found. However, the range of homogeneity of the several phases was not studied. Gulbransen and Andrew" recently studied the phase diagram of this system by X-ray diffraction methods and by a thermodynamic method based on decomposition pressure measurements. The results showed that only two hydride phases existed for low temperatures, the 6 and the .-phases of Hagg.' Both phases had broad regions of homogeneity. The lower limit of the two-phase region of a and d-phases suggested a terminal solubility of 4 atomic pct at 500°C. This value was in agreement with the results of Schwartz and Mallett.' To avoid hydrogen embrittlement at low temperatures, it was necessary to heat the metal in high vacuum at elevated temperatures. To choose the conditions of temperature and high vacuum, it was

Jan 1, 1956

By Hans Lundberg

By electrical prospecting, orebodies that do not otherwise manifest themselves at the surface may be located. Conditions favorable to success with the methods are: Favorable geological conditions, such a proportion of minerals of good electrical conductivity in the orebody as will render the latter materially a better conductor than the enclosing rock, situation of the orebody within the range of influence of the electrical currents used and in proportion to this range a sufficient area of horizontal cross section of the orebody. The result is to permit of spotting drill holes accurately and to save the expense of drilling barren ground. THE art of prospecting, like other branches of mining, has developed rapidly during the last ten years, mainly because of the advancement of mining geology, but also because of the development of "geophysical methods," which are based on the different physical characters of minerals and rocks, e. g., specific gravity, elasticity, and magnetic and electric properties. These methods have proved of great value, especially in countries where the rock is covered by soil and direct geologic investigation is out of the question. In prospecting for orebodies, the methods based on studying differences in electrical conductivity have proved most successful; for which reason, the methods of electrical prospecting have been subject to the most energetic and systematic work, especially in Sweden. This paper gives a brief description of the methods of electrical prospecting now in use, especially the new electromagnetic methods, which have not been described before. The great differences in the electrical properties, especially in conductivity, between ore minerals and rock minerals are fundamental to all methods of electrical prospecting, for which reason, the electrical conductivity of ore minerals and rock minerals has been carefully studied in connection with and previous to the development of the various methods of prospecting with electricity. Ore minerals with a metallic luster, such as chalcopyrite, iron pyrite, galena, specular iron, magnetite, etc., also graphite and a number of cows, have considerably higher conductivity than the surrounding rock and soil (see Table 1). The figures of the table denote the specific resistance W, expressed in ohms for a cube with an edge of 1 centimeter.

Jan 7, 1925

By E. S. Davenport

IT is indeed an honor and a responsibility to have been selected to present the thirty-fourth in this series of Henry Marion Howe lectures, established to perpetuate the memory of a great teacher and one of America's outstanding scientists. Previous Howe lecturers have established high standards for this annual AIME event. It has been my good fortune to have enjoyed close association with five of these former lecturers; namely, Bain, Grossmann, Johnston, Sosman, and Vilella, all of whom have been prominently identified with the research activities of the organization with which I am connected. Some years ago I had an opportunity to examine a letter written by Professor Howe in 1904. This document was particularly interesting to me since I never had the privilege of personal acquaintance with Professor Howe and do not recall even having seen him during his long and active career. In view of the fact that the letter dealt, to some extent, with matters related to the subject of today's lecture, I would like to quote briefly from it. The letter is datelined, "Bad Kissingen, June 11, 1904." The salutation reads, "Dear Bradley," which suggests that it was probably addressed to Bradley Stoughton, who, I believe, was working with Howe at Columbia University at that time. The letter reads, in part, as follows: "Austenite and Martensite. I have not examined what Osmond says in his new book. His former remarks about austenite I found very confusing, indeed unintelligible. I think we can reconcile matters well enough for the present by assuming that martensite is a transition step between austenite at one end and ferrite and cementite at the other. Above critical range for steel of 0 to 1.80 carbon, austenite is normal state; below Ar1, ferrite and cementite are normal." The letter then continues with a discussion of Osmond's ideas on metallographic nomenclature, particularly his use of the terms martensite, troostite, and sorbite, including the following pointed comment: "For common purposes it seems to me unwise to drag them in, and much simpler to confine ourselves to the end stages Austenite Ferrite plus Cementite Osmond does not really know his own mind— or does not clarify his ideas to others—as to nomenclature." Thus we see that, as far back as 1904, the transformation of austenite, and the products of that

Jan 1, 1958

By C. W. Allen, L. C. Moore

THE Mather mine, of the Negaunee Mine Co., is within the limits of the City of Ishpeming, on the Marquette iron- range in Michigan's Upper Peninsula. It is named for William G. Mather, who has served as President, and Chairman of the Board, of The Cleveland-Cliffs Iron Co. for well over 50 years. The property comprises nearly the square mile of section 2, T.47 N. R.27 W., which, except for 20 acres in the northeast corner, was leased by The Cleveland-Cliffs Iron Co. to the Negaunee company. The latter is a partnership of Cleveland-Cliffs and the Bethlehem Steel Co., organized to equip the property, retaining Cliffs in charge as operator. Shipments of ore from this area are mainly through Marquette, which is 16 miles to the northeast on Lake Superior, or through Escanaba, a Lake Michigan port, 65 miles to the south. Cleveland-Cliffs, in 1943, operated 12 mines in the Lake Superior district, with shipments of 6,635,576 tons for the year. GEOLOGY The north footwall of the Marquette Range synclinorium outcrops near the north line of sec. 2, the iron formation dipping to the south at an angle of about 40º. The south side of the trough reappears at a distance of 4 ½ miles on sec. 26 and the surface geology between shows iron formation or intrusive diorites. The latter are harder than most phases of the iron formation and, as a result of glacial action, appear as buttes or low-lying hills. The general elevation of sec. 2 is about 1450 ft. above sea level, or 850ft. above Lake Superior, and the higher diorite outcroppings about 1600 ft. above sea level. The geological structure has been complicated by a series of major and minor faults, one of which may be illustrated by the diorite sheet, which tilts south with the iron formation in the north half of the section and then reappears near the center to repeat this sequence. Sectionally the geological series includes a nearly eroded capping of Goodrich quartzite followed by the considerable thickness of Negaunee iron formation, which is cut by intrusive dikes or diorite sheets, and underlain by the Siamo slates grading into quartzites. The ore deposits occur mainly in troughs formed by the intersection of impervious dikes and the footwall slate, but include locally enriched lenses or bands in the iron formation and also interbedded with the Siamo slate. The ore is a soft red hematite with an indicated dried analysis from the surface drilling to date of 61.50 per cent Fe, 0.134 per cent P, 5.40 per cent Si, 2.87 per cent Al and 0.015 per cent S. EXPLORATION A diamond-drilling campaign started in 1937 actually had its inception in 1917, when a number of shallow test holes were put down for the purpose of locating ore that might be quickly developed and mined

Jan 1, 1945

By T. W. Bossert

MELTING is the initial step in the fabricating of all aluminum and aluminum-alloy products. Its function may be considered as threefold: to improve the metal quality, to adjust the composition, and to change the form to that required for subsequent fabrication. Because the melting operation is generally somewhat removed from the final product fabrication, its importance is frequently overlooked. Melting equipment and melting procedures can reflect materially on fabricating procedures as well as on quality and cost of final product. The selection of equipment and the establishment and control of melting procedures, therefore, should be given careful consideration. It is the purpose of this paper to present the various factors that should be considered in establishing melting procedures and in selecting melting equipment. Certain of these are the result of the inherent characteristics of aluminum and can be treated rather specifically. Others depend on the particular production requirements and hence will have to be considered more generally. This paper is intended to cover only the melting of solids, as differentiated from fines, such as borings, turnings, and sawdust. The melting of fines, in many respects, is a subject that should be treated by itself, and practices for melting fines are by no means as standardized as are those for melting solids. The melting of fines is today the subject of considerable developmental interest; hence practices discussed today may soon be replaced by new or improved ones. CHARACTERISTICS OF THE METAL THAT AFFECT MELTING Aluminum and aluminum alloys possess several inherent characteristics that affect the melting problem. Of the physical properties, density, heat content, thermal conductivity, emissivity, and melting temperatures are important because of their effect on equipment design. A list of such properties for commercially pure aluminum is given in Table r, compared with similar properties for iron and copper. The low density of aluminum as well as of the aluminum alloys is of material advantage in the design of melting equipment, in that such equipment can be considerably lighter than similar equipment for handling the heavier metals. The density, however, particularly of the molten metal, is not greatly different from that of the oxides and other nonmetallic materials that develop or become part of the melt during the melting process. Separation of such nonmetallics is not as rapid a process as with some of the other metals, and consideration of this must be made in establishing melting procedures. Sufficient holding time to permit such materials to separate out and, in some cases, fluxing treatments to aid the separation, are required. Since some of these nonmetallics settle to the bottom of the melt, provision should also be

Jan 1, 1946

By H. A. Kuhn

THE Pittsburg coal field in western Pennsylvania, is conceded to be the most important in the world. To measure its importance it is necessary to understand the extent of its service in the various industries of the country. Probably 90 per cent. of the pig iron manufactured in the United States up to the present time has been made by using coke manufactured from the Pittsburg coal seam in western Pennsylvania. This coal field is the foundation on which the city of Pittsburg rests and is the reason for the great growth of the iron industry in the Pittsburg district. Iron ore is brought to this district, not because Pittsburgh is a. natural location, over other locations, for the iron and steel industry-as its position places the manufacturer at the mercy of the railroads-but the ore is brought 1,100 miles to meet the fuel. It can be said that the illuminating-gas industry in the United States has used this coal exclusively to the same extent that the pig-iron maker has used it. It may be also said that 20 to 25 per cent. of the fuel used on railroads in the United States conies from this coal field. The Pittsburg coal field is unquestionably the center of the industrial population of the United States, for in addition to the industries of the district and those closely adjoining, it has tributary to it all the cities and industries along the Great Lakes and practically all of Canada with the exception of the extreme western and eastern ends. It supplies the industries and population west of Duluth and Superior many hundreds of miles. This coal is floated down the Ohio and Mississippi rivers, supplying the towns en route, and is delivered in New Orleans, a distance of 2,200 miles, for approximately SO to 90 c. per ton transportation cost. It is delivered on the docks of Superior and Duluth at a cost of transportation 50 c. a ton less than the cost of transporting the same coal from Pittsburg to a local consumer in Philadelphia. With other Appalachian coals it has large markets east and along the seaboard, especially for byproduct-coke making and the illuminating-gas industry. It is considered the premier railroad fuel of the world on account of the fact that this coal in a given-sized locomotive will probably haul more cars than any other coal in the

Jan 10, 1914

By H. A. Guess

Introduction. History and Production Statements. Southeast Missouri is the oldest of the large producing districts of the United States. The first recorded production from disseminated ores was in 1869, although for many years prior to that time lead had been milled from shallow pockets, and steady growth in production has been shown ever since, the greatest increases being during the past five years. The production by years for each of the operating companies from 1869 to 1907, inclusive, is given in Table I. In Table 11. is given the production by years from 1908 to 1912, inclusive, for the district as a whole, showing the tonnage of crude ore mined, yield in concentrates, average assay of concentrates; yield in metallic lead both per ton of crude ore and in total; also approximate value of the yearly production. It is interesting to note that the production for the 5-yr. period 1908 to 1912, inclusive, is practically equal to the total previous production, viz., the 39-yr. period 1869 to 1907, the summary being as follows:

Jan 1, 1915

Discussion of the paper of W. A. Forbes, presented at the New York Meeting, October, 1913, and printed in Bulletin No. 82, October, 1913, pp. 2477 to 2514.. SAMUEL K. VARNES,* Steelton, Pa.:-We have a gas-cleaning plant consisting of a, centrifugal dry dust catcher, and two rain-type wet scrubbing towers, 25 by 60 ft. each, for rough cleaning of blast-furnace gas. This plant was put in early in 1910, with the intention of cleaning gas for use in hot blast stoves and under boilers, and was so used for several months. Soon after it went into service, the blast-furnace men complained that they could not get as high blast temperatures as they had obtained when using dirty gas. It was decided to run a series of careful tests to determine if this were true and to what degree the apparent results might be affected by other conditions. About 60 tests were run, covering a period of five months, and at the end we came to the conclusion that it did not pay us to scrub the gas for stoves and boilers. The tests were all run upon a single stove, no boiler tests being made, but the conclusions of the stove tests being applied to the boilers. The furnace burden was practically the same for all the tests and averaged: Per Cent. Daquari and other hard ores 57 Nodules 13 Raw Mayari ore 25 Mill cinder and scale 5

Jan 12, 1913

MARCH 15-Industry is rapidly snapping back from another coal crisis, other business news is in general favorable and the outlook through the Spring is by most observers considered quite promising. Most industries report comfortable backlogs of unfilled orders, department store sales in recent weeks have equalled in dollars those of the corresponding period last year, retail sales of automobiles show again over the same period a year ago, and new orders for machine tools are at the highest figures since August 1946. Orders for railway freight cars have shown a very encouraging pickup, with a total of 9385 cars in January and the N. Y. Central alone ordering 4500 in February. Construction continues very active. In January new housing starts totaled 80,000 against 50,000 a year ago and the daily average contract awards, according to the Dodge reports, were 57 pct larger. In the first 22 days of February the increase in awards was 27 pct. Lumber orders since Jan. 1 have run 22 pct above last year. All of these favorable factors bolster the opinion that the upturn in industrial output and employment which began last summer has not yet spent itself and that the setback caused by the strikes will be made up when people get back to work. Only in a few lines are there indications that primary production may be outrunning the consumption of finished goods, although inventory build-up would seem to be rather modest as the National Association of Purchasing Agents reported in February that 78 pct of its members were buying for 60 days or less. Industrial prices as a whole show no significant trend despite the continued alarm over both the immediate and the long-term possibility of inflation caused primarily by the government's increasing expenditure and its inability to balance the budget. A recent advance of 1.9 pct in primary market prices is viewed by some people as the surface symptom of renewed inflation, but even so it is more than two years since the alltime high was reached by the daily index of sensitive commodities in November 1947. Over two years have passed since prices received by farmers hit their peak and about a year and a half since all wholesale prices and the consumer price index touched their highest points in August 1948. The decline in the wholesale price index has been almost continuous, interrupted only twice by slight advances in the monthly figures from February to March 1949, and, later in the year, from August to September. Of course, this continued decline in the last half of 1949 largely reflects a downward movement in farm and food prices. Wholesale prices for commodities other than farm and food leveled out after June and now stand only slightly under the June level. Farm products are down by 22 pct from January and by 18.6 pct from August 1948. Food prices are down only slightly less. Consequently, the farm price support program is in serious trouble and has imposed a heavy financial burden on the Treasury. In those commodities other than farm products only building materials, chemicals and textiles have come down as much as the average, while housefurnishings and metals and their products have fallen hardly at all. Glancing away from the domestic front, the results of the British general election indicated a highly inconvenient situation, that public opinion there is so exactly deadlocked as to divest the victors of much ability to make forceful decisions or create significant policy. It is generally considered that another election in the near future would give substantially the same result. The British people are equally divided and the politicians are not likely to precipitate another appeal to the country until there is manifest reason to believe that external and internal circumstances have changed sufficiently to permit one party or the other to obtain a decisive verdict. Because of the lack of a clear mandate steel nationalization will likely lag in Britain. In the meantime there is considerable discussion going on as to whether the European steel industries as a whole are at a disadvantage in world competition with the American industry. An article in the "Statistical Bulletin" for January of the British Iron and Steel Federation takes issue on this point with the authors of the Geneva report, observing that they wrote before devaluation, and this particular conclusion "has been overtaken by events." The "Bulletin" also contends that the statement was in any case incorrect so far as Britain was concerned, and that it was based on scanty and insufficient evidence. To support the rebuttal a detailed and extensive comparison is made of the home prices of certain steel products in Britain and in other countries of the world. The accompanying table gives a selection of the prices published. It sets out the changed position since devaluation and since the recent increases in American steel prices. These are home market prices; no doubt in competitive export business some of the price levels could be brought closer together at need.

Jan 4, 1950

By John S. Alexander

By E. H. Rose

From the more distant members and some not so distant, the plaint is often heard that they cannot justify the expense and time required to attend the AIME Annual Meeting. Almost invariably, the reason given takes this form: "I just don't see that I would get enough out of it." Often the would-be clincher is added: "Besides, the meat of it all comes out in print anyway." Not long ago, a group of us who have seldom missed a meeting in recent years fell to discussing this phenomenon, and found ourselves in emphatic agreement that anyone holding such a belief indicates by his first remark that he does not know how to attend a convention, and by his second, proves it. He is, by and large, the man who has never been there, and of him, there are many.

Jan 1, 1949

By N. A. Tiner, Saara Asunmaa

The early stages of nucleation of vacuunz-deposited gold coatings on electropolished surfaces of pure nickel and binary alloys of Ni-A1 and Ni-Ti have been studied, employing carefully controlled temperature and vacuum conditions. The preferential nucleation of gold on slip-plane edges on the crystal surfaces gave rise to a very pronounced decoration effect which was used in studying the morphology of the pain boundaries, etch pits, and slip planes on crystal faces. Characteristic surface patterns were observed with local dimensional variations. Most pronounced geometric patterns were ohserved in the pain boundaries of nickel and on the crystal faces of Ni-A1 alloy. The nucleation behauior of gold indicates contamination on the Ni-T1 alloy and the getter properties of titanium are presented as a tentative interpretation for the detected contamination. The markings and imperfections on cleavage surfaces of crystals have long been observed by optical microscopy.1,2 Surface-replica techniques are also used to detect the smallest steps and structural details on crystal surfaces by electron microscopy. Recently, Bassett3-5 and Sella, Conjeaud, and Trillat 6 have shown that, when gold is deposited onto a rocksalt cleavage surface, there is preferential nucleation at steps and slip-plane edges on the crystal surface. This gives rise to a very pronounced decoration effect which is invaluable for revealing the lattice steps on a cleavage surface. According to Bassett,3 gold atoms arriving during vacuum evaporation at the crystal surface have a certain mobility on the surface after arrival, particularly at elevated temperature. If a significant

Jan 1, 1964

By W. Griffith

The purpose of this paper is to make public record of new information in regard to the sustaining power of artificial mine-roof supports (not timber props), the result of investigations recently made in the anthracite coal fields of Pennsylvania. First.—By the "Scranton Mine Cave Commission," appointed to investigate the mining conditions under the City of Scranton. Second.—By the "Pennsylvania Mine Cave Commission," appointed by the Governor to investigate the general subject of mine caves in the anthracite region of Pennsylvania. Third.-—By the personal researches and tests made by the author in an effort to secure a better artificial mine-roof or surface support. During the progress of the work of the Scranton Mine Cave Commission, the Engineers for the Commission, Messrs. Conner and Griffith, being aware of the general lack of exact information in the engineering profession as to the strength of the ordinary artificial mine-roof or surface support, and particularly the stronger kinds, such as mine cogs, rock piers, etc., had tests made at the Fritz Engineering Laboratory at Lehigh University, to determine the sustaining power under various compressions of the several kinds of artificial mine supports in use in the anthracite region of Pennsylvania. A report of these tests wasincluded in the report of this Commission, which was published as Bulletin No. 25 of the United States Bureau of Mines, Washington. A similar series of tests, more extensive and more elaborately planned, were subsequently made for the Pennsylvania Minc Cave Commission at the U. S. Government Testing Laboratory at Pittsburgh, Pa. The report of this Commission was made to the Governor, but has not yet been published. The author, during his connection with the Scranton Mine Cave Commission, observed that of all the various devices employed for sustaining the roof of coal mines, the one universally used and the best

Jan 1, 1918