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By A. E. Bellis

The time effect in reheating certain steels below the critical range is very marked. The increased toughness, shock-resisting power, and machinability of steel subjected to a long, high drawing temperature has been thoroughly demonstrated and is of practical importance, particularly in the manufacture of L'smokeless" rifle-barrel steel. The time effect in tempering is most important when a maximum drawing effect is desired, in which case the highest physical properties as well as ease of machining are important considerations. These are the conditions in drilling a rifle barrel. A hole, 0.30 in. in diameter and 24 in. long for the Springfield rifle, and 30 in. long for the Russian military rifle, has to be drilled in the heat-treated material. This barrel-drilling operation is probably the most difficult one in rifle manufacture, and anyone who has been connected with rifle manufacture knows how seriously production is affected when "hard" or non-uniform steel for barrels is encountered. The importance of high physical properties (tensile strength, toughness and resilience) in a rifle barrel is obvious. The physical properties of two different lots of barrel steel are given below. The first lot, No. 1, gave serious trouble in the drilling operation; the second gave no trouble at all. No. 1 No. 2 Elastic limit, lb. per sq. in.................... 117,450 116,800 Tensile strength, Ib. per sq. in................. 132,500 131,750 Elongation, per cent........................ 16.0 20.0 Reduction of area, per cent................... 42.1 51.0 Impact strength, ft.-lb. per sq. in.............. 450.0 520.0 This difference in machining and physical properties was due entirely to the time of reheating. The first lot was given a reheating time of 30 min., the second lot remained at the reheating temperature 2 hr. Both

Jan 1, 1918

By AIME AIME

FEW mining schools possess an art gallery and certainly none can equal the collection of paintings depicting the mineral industries now hanging in the comparatively new building of the School of Mineral Industries at The Pennsylvania State College. Dean Steidle, who conceived the idea, early this spring boasted of 55 paintings in the collection, by 24 different artists, the gallery being appraised at $18,000. Since then, eleven additional paintings have been added. Opportunity will he presented for an inspection at the meeting of the Industrial Minerals Division, to be held at the College, Sept. 24-26.

Jan 1, 1936

By AIME AIME

THOUGH Frank Wardlaw was born in the East- at Schroon Lake, N. Y., on July 14, 1887-and was educated in New York City-Columbia, E.M., 1916 he has spent his entire professional life in the West, and is still there, as assistant general manager of the Inspiration Consolidated Copper Co., in Arizona. His first jobs were as miner and surveyor for the Utah Consolidated Mining Co., at Bingham, where he worked under A. S. Winther, now general manager of Inspiration's adjoining big neighbor, the Miami Copper Co. After rising to the position of chief engineer and geologist, Mr. Ward- law left Utah Consolidated to go to Chile for two years with the Braden Copper Co. Then he returned to his

Jan 1, 1940

"The cleanliness and system evidenced in the accompanying photographs of the West Steward change-house will appeal to all mine operators. This design is the most efficient in use at Butte. It is the standard which will probably be used in Butte in all future construction and is the result of a long period of investigation and experimenting. It is important that such a structure be as nearly fire-proof as possible, because of the frequent fires originating within the lockers from matches, etc., in the men's clothes. The concrete floors permit the thorough washing of the building whenever necessary.The lockers are roomy and well ventilated. They are constructed of sheet steel and are warmed from below by steam pipes."

Jan 1, 1913

By R. A. Feemster, C. M. Rader

Because of the necessity for taking regularly occurring open-flow tests in prorated high-pressure oil fields, much gas is turned to atmosphere by way of vertical vent lines leading away from the oil and gas separator. In the past, measurement of such gas has been accomplished by several methods, usually by use of the open-flow Pitot tube. The use of the closed-flow Pitot tube has been avoided apparently chiefly because the ordinary vent-line hook-up makes it necessary to apply the instrument closer to a bend, valve, or obstruction in the pipe than is recommended by rules of good practice. The many advantages that would result from the application of the closed-flow Pitot tube prompted investigation of the actual effect upon quantity rate of flow measurements computed from data obtained with the tube in a normal working position, which is closer to the tee at the base of the vent riser than is usually considered as giving highly accurate results. An effort Was first made to compare the results thus obtained to those under ideal conditions and at high velocities To make this comparison, knowledge of the characteristics of gas flowing at very high velocities is essential. Research for such information indicated that little or no work had been done that would give data necessary for such a comparison, therefore the problem was changed to a test designed to determine the relationship between quantity rates of flow as measured by an orifice meter and a Pitot tube placed at the center of a pipe eight diameters from a tee or ell at the base of a vent riser, through which gas is flowing under low pressures at very high velocities. To determine this relationship, a series of tests was run on a number of 8-in. iron-pipe vent riser., in which the Pitot tube data were taken at the position as stated above. Gas from a wet-gas gathering system was passed through an orifice meter setting and thence to atmosphere by way of the vents. Data were taken simultaneously from the orifice meter and Pitot tube from which computations for comparisons were made. The actual method of comparison is discussed later in this paper. Since Pitot-tube information is usually given in general terms, and not readily usable, it will be the purpose of this paper to discuss the applica-

Jan 1, 1934

By William Kent

In a paper by Mr. Frank Firmstone, published in vol. iv, of the Transactions of the Institute, on " Comparison of Results from Open-topped and Closed-topped Furnaces," the regularity of the average grade of pig iron procluced by the furnace under different conditions is expressed by means of a curve or diagram. The object of this note is to show that the graphic method, or that of representing variations by plotted curves or diagrams, is capable of a much more extended application to blast-furnace records, making a valuable auxiliary to the " furnace hook," and that by it the practical metallurgist may obtain at a glance information concerning the variations of the furnace during long periods, which could be found in the furnace book only after a tedious search. Plate XII is a graphic record of an anthracite blast furnace for one month. The table on page 554 gives the figures obtained from the furnace book, together with a record of temperature of the atmosphere, barometric pressure, and moisture in the air, which was obtained from a meteorological observatory not far from the furnace. In the records of a furnace, two of the variable qualities are final results, viz., the quantity of pig iron produced, and its grade; all the other variables are antecedent causes which produce the final results. Of these variable callses which contribute to the quantity of product and its grade, some are partially under the control of the furnace manager, others depend upon the state of the atmosphere, and still others are accidental. Of the first class are the character of the materials charged, and their relative proportions, their mechanical conditions, as wetor dry, large or small pieces, etc., the revolutions of the engine, the heat and pressure of blast, and the distribution of the charge. Of the second class are the number of pounds of air blown into the furnace for each stroke of the engine, the amount of moisture in the air, and the condition of the chimney draughts. These vary largely with the season of the year. Of the third class is the leaking of a tuyere or a temporary stoppage. To keep a record of this kind for a whole year, it is only necessary to procure a sheet of common profile or cross section paper, about 38 inches long and 8 or 10 inches wide, with cross lines ruled about 0.1 of an inch apart. The vertical lines, or those in direction of the

Jan 1, 1879

By J. J. Brown

The ore-hearth was the earliest type of furnace used in smelting Mississippi Valley lead-ores, which are very pure, and low in silver-content. The first smelters made no attempts to recover lead from the smoke; and since about 15 per cent. of the lead in the charge escaped in this manner, early practice with the hearth was decidedly wasteful. At most of the large smelting-plants blast-furnaces with auxiliary roasters were substituted for the hearths long ago. But, upon the introduction of the Lewis and Bartlett bag-process for collecting fume, the ore-hearth was used by companies engaged in the manufacture of pigments, simply on account of the large percentage of fume made by it. In fact, the extraction of lead mas kept down by the use of hot blast and other devices. During recent years, however, several smelting companies have realized that the preliminary roasting of galena for the blast-furnace is not economical, and have, therefore, replaced the roasting-furnace with a modification of the old Scotch hearth, in which a large percentage of the lead in a charge is

Jan 1, 1912

By Helen L. Cannon

BOTANICAL methods of prospecting for metalliferous ores are based on the premise that deposits at depth may be reflected chemically in surface vegetation. For the past several years, on behalf of the Atomic Energy Commission, the U. S. Geological Survey has investigated on the Colorado Plateau the application of botanical methods to uranium prospecting. Results suggest that orebodies may be found under a considerable cover of barren sandstone through the absorption of uranium and associated trace elements by plants growing at the ground surface. Plant physiologists have demonstrated that uranium is a necessary nutrient for plant growth and therefore is present in all plants.' The amount present is small but measurable. The absorption of uranium by plants growing over ore deposits forms

Jan 1, 1955

By G. W. Toop

Jan 1, 1965

By Howland Bancroft, Louis S. Cates

WE have come a long way since the order of the day was the chance discovery of mineral deposits, breaking rock with fire and water, melting metals in open fires in holes in the ground or in primitive furnaces, digging pits to collect. oil seepages, burning eroded coal outcrops to develop heat, and so on. During the past 5500 years, gradual improvements in methods and equipment have come about, explosives have been developed and used, steel has been used in increasing quantities and effectiveness as its physical and chemical characteristics, and composition have been altered and made to serve specific ends, hand equipment has given way to almost completely mechanized operation Thus, by the aid of mechanical equipment, one person is now able to move several thousand times as much material as one person was able to move a relatively few years ago. When this Institute was formed 75 years ago, the Suez Canal had been open to traffic but three years. It had taken ten years to complete and was built under the direction of French engineers by workers of whom many were girls. During the first four years of construction, these workers dug up the sand with their fingers, threw it into rush baskets, carried the load a hundred feet or so and dumped it 2 (With the termination of forced labor, dredgers completed the digging of the channel.) At the present time there is in use in the United

Jan 1, 1947

By Walter Dake

THE mining engineer is being more generally called on to examine and report on properties where the introduction of mechanical loaders is proposed, and as the use of these labor-saving devices presents an entirely different problem from that of hand-loading, an outline of procedure is herewith pre¬sented based on five years of intensive field experience in making such studies. It is impossible to outline an examination which will cover every condition but the most important variables are noted and the re¬port may be amplified or abridged to suit individual mine requirements. There are, of course, exceptional cases in which a single minor variable will determine the final conclusion; the result of mechanical loader application can be, estimated within close limits by considering all variables listed and taking into account the sum of all those found to be applicable to the property under examination. It is necessary that a high degree of accuracy be exercised in the analysis of conditions, and that a relatively narrow margin be figured on all estimates of tonnage outputs and costs. In making an examination for this purpose the data as to company name, business address, name of mine, geographical location, rail or water connections, type of mine (whether shaft, slope, or drift), and the name of seam should, of course, be included, to be followed by the minimum, maximum, and average thickness of seam, a brief description of the charac¬teristics of the coal, the impurities contained, location of regular impurities or partings, together with nota¬tion as to quality, uses, and-markets for the coal. It is also necessary to make cross-sections of the seam so that face preparation may be studied in an effort to eliminate all regularly-occurring impurities at the working place. The possibilities for further cost re¬ductions by the removal and gobbling of partings under¬ground before mechanically ? loading out a face are sufficiently great to warrant careful study and analysis. The classification of the mine from the standpoint of gaseous or non-gaseous operation will determine the general type of electrical equipment needed. A notation regarding the power whether generated at the mine or purchased, together with the amount, voltage, and type of current available is necessary since these matters determine the exact type of elec¬trical equipment to be used. A brief description of the ventilating system, giving type of fan, amount. of air delivered, water gage, and whether force or ex¬haust type, will enable the engineer' to figure venti¬lating requirements per man under mechanical loading practices. The pitch of seam in degrees, the pitch of working faces, and a brief description of rolls or horsebacks should be included, as these affect the efficiency of mechanical loading and, therefore, the economic re¬sults obtainable. -Notations should be made as to the amount of water found in working faces, and whether pumping, sprinkling or rock-dusting methods should be considered. As the character of the floor affects the operation of the machine at the face if a cater¬pillar-tread type, its hardness should be determined, and also whether impurities consisting of floor ma¬terial are likely to be loaded with the coal. The char¬acter of the roof and overlying stratification determine the mining system and width of roof span at work¬ing faces. It therefore directly regulates the amount of tonnage to be loaded by machines without a move from one place to another.

Jan 12, 1927

Henry D. Hibbard, High Bridge, N. J. (Communication to the Secretary): There is one chemical factor which has not been considered in the author's tabulation of tests, but which is none the . less important because it cannot be practically estimated, and that is the element oxygen. This element has been, and probably will continue for some time to be, one of the great causes of the continual discrepancies between the chemical and physical properties of steel. Probably oxygen occurs, in important proportions, only in soft steel, such as that which we are now considering. In this steel its physical effect is to diminish tensile strength and elongation. The percentage of oxygen in the steel, under working-conditions that are as uniform as possible, is likely to vary inversely as that of the manganese, or perhaps, and more probably, it may bear even an inverse geometrical ratio to the manganese-content. At all events, to follow the author's plan, the line representing the loss of strength due to oxygen is probably a curve. Plotted by itself, the line would probably be straight; that is, the decrease in strength would be proportional to the increase in oxygen, but if the results were superposed on the percentages of manganese, they would give a curve, because the percentages of oxygen increase faster than those of manganese decrease. Were the oxygen-line to be developed and added to the diagram, it would seem that the manganese-line should then be straight. Due allowance for the effect of oxygen, therefore, would modify two features of the paper. It would increase the figure for the strength of pure iron from 38,000 to about 45;000 pounds per square inch, and it would straighten out the manganese-curve. The manganese-line in the paper is curved between 0.50 and 0.20 per cent. Above 0.50 per cent. it is straight, which may be ascribed

Jan 1, 1893

Jan 1, 1969

By Rossiter W. Raymond

The 12th of April, 1877, witnessed the celebration, at Freiberg, Saxony, of an event profoundly important for the ancient mining industry of that district, and full of interest to mining engineers throughout the world—namely, the connection of the famous Roth-

Jan 1, 1879

The Institute is custodian of funds for support of numerous gold medals and prizes and has representatives on boards awarding still others. Details regarding the Institute Awards are given below. The Institute is represented on the boards of the John Fritz Medal, the Hoover Medal and the Washington Award, in connection with the three national societies of Civil, Mechanical and Electrical engineering; and, also, in the case of the Washington Award, with the Western Society of Engineers.

Jan 1, 1923

By John M. Bostwick, James C. Bradbury

Bitumen is a general term for a group of materials composed of mixtures of hydrocarbons that are fusible and soluble in carbon disulfide. Included in the group are petroleum, asphalts, asphaltites, and mineral waxes. Asphalt is a dark-colored, cementitious solid or semisolid, which generally softens on heating and resumes a more viscous or solid state when cooled. It is found in native form in fissures and pore spaces in rocks and as lakes. It is also obtained from the residues produced in petroleum refining. Asphaltites are black, naturally occurring solid bitumens. They are generally shiny and break with a conchoidal fracture. Common asphaltites are gilsonite (uintahite), grahamite, and glance pitch. Mineral waxes are solid or semisolid, relatively nonvolatile bitumens of various colors, having an unctuous feel and waxy luster, Of the native waxes, ozokerite is the best known. Montan wax is also classed as a natural wax, although it never occurs in the pure state and must be extracted from lignite or cannel coal (Ladoo, 1920). Mineral waxes may also be obtained by pyroprocessing of petroleum, lignite, and peat. Pyrobitumens are dark-colored, solid hydrocarbons that are infusible and relatively insoluble in carbon disulfide. They are so-called because they will yield liquid and gaseous hydrocarbons only when heated. Asphaltic pyrobitumens are defined as "substantially free of oxygenated bodies" and include wurtzilite (elaterite), albertite, and impsonite (Thrush, 1968). Nonasphaltic pyrobitumens contain oxygenated bodies; examples are coal and peat. The nonasphaltic type will not be discussed further. Petroleum Asphalts Asphalts refined from crude petroleum have almost completely replaced the native types. Refineries can produce asphalts in every desirable grade more economically and in greater quantity than the native types and with a variety of properties that meet the requirements of the various manufacturers using them. For all practical purposes, it is estimated that more than 95% of the asphalts consumed in the United States are refined from crude petroleum (private communication). Native Asphalts Native asphalts are dark brown or black, semisolid or solid substances that, in theory, formed by slow, natural fractionation of crude petroleum at or near the surface of the earth (Goulston, 1938). They are colloidal systems of high molecular weight components dispersed in a medium consisting of low molecular weight components (Pracy, 1954). Native asphalts may occur as lakes, as impregnations of rock (rock asphalt) or as deposits consisting of mixtures of natural asphalt and mineral matter in various proportions (Stern, 1960). Practical use of native asphalt dates to about 3000 B.C. It was mined from surface pits or lakes and used, then as now, for masonry mortar, waterproofing aqueducts and tunnels, binders for road construction, and as an article of commerce (Miller, 1938). Generally the native asphalts find little commercial use today except where they are geographically abundant, easily mined and transported, or have specific or special application. Petroleum-refined asphalt is produced by unusually economical techniques and is much less costly to use. The largest and best known of the lake deposits is that on the Island of Trinidad, where the lake covers an area of 114 acres and is 285 ft deep at its center (Stem, 1960). The lake asphalt is refined by heating to evaporate in-

Jan 1, 1983

By Charles P. Williams

THE determinations of the specific gravities of a number of samples of lead produced in Missouri, which form the subject of this note, were undertaken with the view of ascertaining if any approximation to the purity of such leads could be reached in this manner. The results would seem to indicate that, whatever value the method may have in the case of the crude and more impure

Jan 1, 1877

By Charles P. Williams

The determinations of the specific gravities of a number of samples of lead produced in Missouri, which form the subject of this note, were undertaken with the view of ascertaining if any approximation to the purity of such leads could be reached in this manner. The results would seem to indicate that, whatever value the method may have in the case of the crude and more impure

Jan 1, 1922

Jan 1, 1922