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By C. W. MacGregor

IN the testing of materials there exist various methods of recording graphically the behavior of a material subjected to tensile stress. Prob-ably the most common method is to plot the tensile stress So, obtained by dividing the load P by the original area of cross section AO at the start of the test, as a function of the strain ?o, which is obtained by dividing the ?Lo or the change in the gauge length by the original gauge length Lo. A list of the symbols used here is given in Table 1. This method, while it has proved useful in the routine testing and comparison of various materials, does not have a very sound physical basis, as was first pointed out by P. Ludwik1, and consequently does not afford a very deep insight into the true physical behavior of the material under stress. Among the objections to this method may be mentioned: (1) that by dividing the load P at any stage of the test by the original area Ao a fictitious stress is obtained, which does not actually exist; (2) that the strain ?o = ?Lo /Lo is not an exact expression for the true strain for large values of ?Lo in per cent of Lo; (3) that when necking starts the strain varies considerably along the gauge length and the above expression no longer gives the true strain existing at any point on the outside of the bar; and (4) that the axial strain varies over the cross section of the necked portion and ?o does not represent an average of these strains over the cross section. Stresses taken from such a diagram would be only approximate and, if used to compare results of a test on a given material under simple tension with results obtained under combined stresses, certain errors would he thus introduced. In order to overcome some of these objections, various methods have been suggested, both as to the quantities to be measured and as to their graphical representation. In some cases the so-called "true stress," obtained by dividing the load P by the actual area of cross section A existing when the load P was applied, is plotted as a function of the strain

Jan 1, 1937

By R. W. Ph. D. Raymond

PROFESSOR W. P. BLAKE, in a note to his Catalogue of California Minerals, pointed out that the mining districts of the Pacific slope are arranged in parallel zones, following the prevailing direction of the mountain ranges. This interesting generalization has been more fully illustrated and connected with the geological history of the country by Mr. Clarence King, who sums tip the observed phenomena as follows: "The Pacific coast ranges upon the west carry quicksilver, tin, and chromic iron. The next belt is that of the Sierra Nevada and Oregon Cascades, which, upon their west slope, bear two zones, a foot-hill chain of copper mines, and a middle line of gold deposits. These gold veins and the resultant placer mines extend far into Alaska, characterized by the occurrence of gold in quartz, by a small amount of that metal which is entangled in iron sulphurets, and by occupying splits in the upturned metamorphic strata of the Jurassic age. Lying to the east of this zone, along the east base of the Sierras, and stretching southward into Mexico, is a chain of silver mines, containing comparatively little base metal, and frequently included in volcanic rocks. Through Middle Mexico, Arizona, Middle Nevada, and Central Idaho is another line of silver mines, mineralized with complicated association of the base metals, and more often occurring in older rocks. Through New Mexico, Utah, and Western Montana lies another zone of argentiferous galena lodes. To the east, again, the New Mexico, Colorado, Wyoming, and Montana gold belt is an extremely well-defined and continuous chain of deposits." These seven longitudinal zones or chains of mineral deposits must

Jan 1, 1873

By H. M. Howe

The tenacity with which a bad name adheres to a process is well illustrated by the prevalent belief in the irregularity of the product of the Bessemer converter. We have been lately told by an eloquent member that lack of uniformity is the name of Bessemer steel, and that uniform soft steel can only be made in the Clapp-Griffiths Bessemer converter. Yet I believe that, however irregular the percentage of carbon in Bessemer steel may have been formerly, to-day it is well-nigh completely under control. Indeed, the results of a large number of analyses that I' have studied go to show that the

Jan 1, 1887

By K. V. S. Sastry, M. Cross

A summary of recent progress in understanding the main factors affecting the pelletization of fine particles is presented. A scheme for categorizing the mechanisms responsible for pellet growth is out- lined and laboratory methods to both identify the important growth mechanisms and quantify the effects of the major factors influencing the rate of pelletization are described. Next laboratory and mathematical simulations of the commercial process involved in pelletizing iron ore concentrates, are presented. The operational instabilities associated with this pelletization process are described and subjected to a control theory analysis. This analysis, in conjunction with the mathematical models, is used to both explain existing control problems and assess the effectiveness of possible circuit redesigns at producing a more stable and controllable operation. Although much of the discussion is in the context of iron ore pelletizing the approach developed to analyze the agglomeration behavior of these concentrates should apply to most other fine particle systems.

Jan 1, 1980

By Donald W. Gentry, John F. Abel

This paper presents some of the results of a rock mechanics instrumentation program designed for, and implemented at. longwall panel 4N at the York Canyon Mine near Raton, New Mexico. The objective of this particular instrumentation program was to determine the response of the rock mass to longwall mining of a thick coal seam utilizing shield-type supports. Measurements were made in the rock along the ground surface, above the coal seam, in the coal seam, and immediately below the coal seam. Longwall test panel 4N had a total developed length of 762 m (2500 ft) and a face width of 168 m (550 ft), [Fig. 1]. The seam mining height in the panel area was approximately 3 m (10 ft). The average depth of overburden above the panel is 107 m (350 ft) although it ranges from 73-134 m (240-440 ft). Roof support at the face was provided by 116 Hemscheidt 320 HSL shields. These shield-type supports weigh 11.4 metric tons each.

Jan 1, 1979

By Byron B. Boatright

The energy which causes oil and gas to flow from a reservoir formation into a well depends upon a differential between the formation pressure and the pressure at the well face. This differential pressure may be the result of any one of at least three forces, or a combination of them. Gas under pressure in an oil-producing formation (part of the gas may be in solution and part in contact with the oil) is the principal source of energy for producing oil in most fields. In some fields, however, hydrostatic pressure due to water in contact with the oil and/or the force of gravity may be important factors in causing oil to flow into a well. Still another force affecting oil movement is suggested by some students of the problem; the force dependent upon the phenomenon of capillarity. Hydrostatic pressure is seldom the only source of energy in an oil sand, but it is commonly an adjunct to the compressed gas in the formation. Where this condition prevails, increased production may be obtained provided the water encroachment is properly controlled. In addition to the water-drive effect, the hydrostatic head may tend to maintain pressure in the formation by progressively reducing the volume of the reservoir as withdrawals to the surface are made through the producing wells. The action of the force of gravity on the oil in a formation is of relatively small importance, from an energy standpoint, until the last stage of the productive life of a well is reached. This force is the only remaining natural source of energy in some of the eastern fields, but in most of the deep wells of the Mid-Continent and California districts the force of gravity can be precluded as a source of energy, because the wells reach their economic limit of production before the force of gravity becomes an important factor in moving oil to the wells. Since the majority of fields produce oil chiefly by reason of the gas pressure in the oil horizons, the following treatment deals mainly with factors that influence gas-energy relationships. Gas-energy Relationships Formation Pressures The gas pressures existing in oil-producing formations may be the result of a combination of several contributing factors. All fluids under

Jan 1, 1932

By C. S. Chang

Replacement of active groups in corn starch, as shown by results of the starch derivatives tested, impairs rather than improves the value of corn starch as a selective iron oxide depressant. Increased ability to depress iron oxides is generally accompanied by a parallel ability to depress quartz. PEARL starch, a corn starch prepared with a minimum of alteration, is a good selective depressant for iron oxide minerals.' From what is known of the complex chemistry of corn starch, there is evidence that it consists of a mixture of saturated giant polymeric molecules, both straight and branch-chained, the constituents consisting of glucose units with hydroxyl radicals as active or polar groups. To add to the existing knowledge of the chemistry of the flotation process, it is desirable to ascertain the effects on the corn starch as an iron oxide depres-

Jan 1, 1955

By W. J. Garmoe

The Carr Fork mine is located approximately 50 kilometers southwest of Salt Lake City, Utah, in the Bingham or West Mountain District, adjacent to the Bingham open pit copper mine. Applied geology at Carr Fork, by Anaconda Minerals Company personnel includes detailed geologic mapping and sampling of underground workings, logging and sampling of drill core and cuttings, and the preparation and posting of geologic maps and cross sections for geologic interpretation, ore reserve calculation, mine operations, and long range planning. Accurate and easily understood graphic recording of Carr Fork geology is essential for optimum use by operating and engineering personnel. The design and implementation of exploration, development and definition drilling programs, research into geological spatial relationships, and analysis of structural complexities of the Carr Fork deposit are a1 so integral parts of the applied geology program.

Jan 1, 1984

By R. P. Marshall, L. P. Costas

The solid solubility of lithium in aluminum was determined by two independent techniques, electrical resistivity and microhardness, and the results are in close agreement. The solubility limits X-ray diffraction studies of the intermetallic compound LiAl indicate that its composition is nearly independent of temperature when in equilibrium with the terminal solid solution of aluminum. THE investigation of the aluminum-rich portion of the aluminum-lithium system at the Savannah River Laboratory was prompted by the observation that over-aged alloys consistently differed from the equilibrium states predicted by the latest published diagrams. Chemical analyses of these alloys showed their impurity contents to be quite low; therefore, the results obtained should have very nearly coincided with true equilibrium. A survey of the literature disclosed that previous studies had been made with metallographicig or electrical resistivity methods,4'5 but that agreement between results and technique was poor as evidenced in Fig. 1, which also includes the present results for comparison. The discrepancies have been attributed to impurities,3 and this is undoubtedly true in the early work.1'4'5 The latest Studies,''~ conducted with starting materials of higher purity, employed metallographic analysis, a technique that is quite sensitive to local homogeneity and depends strongly on subjective interpretation. In the present work the problem of defining solubility limits was approached in two ways. The first measured a physical property, electrical resistivity, at the equilibrium temperature. The second, a micro-hardness characterization of a diffusion zone, is a room temperature evaluation of a mechanical property under conditions removed from equilibrium. A close correlation between two such basically different approaches would strongly justify confidence in the results. I) MEASUREMENT OF SOLUBILITY OF LITHIUM IN ALUMINUM BY ELECTRICAL RESISTIVITY Experimental Procedure. Alloys for electrical resistivity measurements were made by melting and

Jan 1, 1962

By Wilson B. Emery

The discovery well in the Rock River field, in Carbon County, Wyoming, came in May 1, 1918. The field is on a large anticline having more than 1500 ft. of closure and production is obtained from three sands of the Dakota group. At its peak, production approximated 10,000 bbl. daily and is now averaging 2200 bbl. Total production to Jan. 1, 1930, exceeded 12,500,000 barrels. So far as known to the writer, Rock River was the first light oil field in the Rocky Mountain region to be produced under what we now term unit operation. Though this type of operation was not popularly acclaimed by the oil industry, the Federal Government and the public until many years after the inception of development at Rock River, the officials of the Ohio Oil Co. when acquiring this property were fully cognizant of the economies to be effected by unit ownership and the consequent elimination of competitive drilling and producing of wells, and had this in mind at the time. Thus unit management was introduced in this field at an early date by this company. Area and Management Fig. 1 shows the location of all wells drilled on the Rock River structure and the outline of the productive area as now defined, which amounts to 1380 acres. The hachured line indicates the area now under unit ownership; originally a much larger area was so owned but leases have been canceled as progressive development indicated their lack of oil. The management and operation of the entire productive area is handled by the Ohio Oil Co., which owns the majority working interest. The Continental Oil Co. with a 20 to 35 per cent. interest in much of this acreage, and smaller interests owned by others in some of the leases, constitute the remainder of the ownership. The fee rests in the State of

Jan 1, 1930

By H. Evans, L. A. Hunt

The raw materials used in the blast furnaces at the Geneva Works of U.S. Steel Corp. have a high degree of variability in size-consist and chemical content. To overcome the problems caused by the use of highly variable raw materials in the blast-furnace operation, large blending piles are used. An investigation of the blending system showed that variability was significantly reduced by the use of these blending piles. This paper describes the blending system, the method used to evaluate the effect of the blending system, and the results of the investigation. The remarkable improvement in blast-furnace performance since World War II has been in large measure due to the use of beneficiated burdens to reduce the variation of both chemical analysis and size consist. This practice allows the operator better control of his blast furnace, enabling him to operate more economically and to produce chemically uniform hot metal. Planning for uniformity usually begins during mining by extracting ore from several locations within a pit to produce a final product with a specified analysis. Another approach is to stockpile ores having widely varying analyses in individual piles and then drawing the required amounts from each stockpile to provide a blend with a predetermined analysis. A further improvement in blending procedures is to take ores from several sources, bedding them horizontally in layers and reclaiming by vertical slicing from the blended pile. The last procedure, when properly executed, is one of the best methods for achieving maximum uniformity with highly variable ores. U.S. Steel Corp.'s Geneva Works initially obtained iron ore for their blast furnaces from the Cedar City area of southern Utah. These ores were formed primarily by the replacement of limestone and siltstone formations with solutions containing iron and several other elements. The original iron content of the ores in the ground varied from a high of 70% to practically zero with a minimum acceptable iron content for shipping of 37%. Substantial amounts of silica, calcium, magnesium and alumina were found in the ores along with minor amounts of copper, lead, zinc, nickel, titanium, manganese, phosphorus and sulfur which were sometimes present in detrimental amounts. Iron-to-silica ratios varied considerably throughout

Jan 1, 1968

By L. W. Saperstein, W. B. Wells, L. B. Phelps

Several strip mine spoils are being examined to better understand their physical nature. The spoils were core drilled and each hole was logged using a nuclear geophysical tool to obtain bulk density data. Bulk density is an important property which provides insights into spoil porosity as well as other characteristics. The holes were drilled in spoils representing a variety of overburden removal methods, spoil ages, spoil depths, and area lithology. The relationship between bulk spoil density and mining method, spoil age, spoil depth, particle size, and lithotype is presented.

Jan 1, 1984

By Morris Cohen

It has been known for several years that in certain age-hardenable alloys precipitation of finely divided particles occurs simultaneously with the changes in physical properties; while, in other alloys, these changes take place prior to, or without any, precipitation. The silver-copper alloys are generally considered to be the classical example of the first group, and the aluminum-copper alloys (duralumin) are typical of the second group. The two types of aging are explained by the precipilation theory and the knot theory respectively.‡ It is well recognized now that these theories do not conflict with each other; the one used for a given aging system depends upon which way the alloy in question happens to age-harden. However, previous work on the aluminum-copper al1oys1,2 has shown that if the aging temperature is raised sufficiently the hardening will be accompanied by actual precipitation. In fact, it is quite probable that all of the so-called knot-hardening alloys will harden by precipitation at elevated temperatures. Therefore, a combination of the knot and precipitation theories is necessary to give a complete picture of the agehardening of these alloys, and indicates that knot formation and precipitation are not independent processes. To test the generality of this concept, it is necessary to show that the alloys that commonly harden by precipitation will harden prior to precipitation if the aging temperature is sufficiently lowered. For this reason, it would be well to carefully re-examine the aging characteristics of the silver-copper alloys at aging temperatures somewhat below those used by previous investigators. If hardening can be detected prior to precipitation in these alloys, it will lend great weight to the idea that knot forma-

Jan 1, 1937

By Magnus Troilius

The following is a very rapid method for determining copper in steel. I have found it to give results very closely agreeing with those obtained by galvanic precipitation of the copper. Five grams of steel are dissolved in a mixture of 100 C.C. of water and 10 C.C. of sulphuric acid. When all is dissolved, add 2 C.C.

Jan 1, 1883

By Leslie C. Richards

The competitive position of producers of industrial minerals depends upon the delivered price of their product. Freight charges are a major factor in the sales to consumers. A comparison of freight rates on movements of limestone and silica rock in the Pacific North-west shows a wide variance in mills per ton mile for like hauls, thereby favoring some localities over others.

Jan 2, 1950

By C. S. Barrett

WhEN a collimated beam of protons or other energetic particles is scattered by a single crystal, the emerging particles produce patterns that contain much crystallographic information. Calculations of the trajectories of individual particles can predict with reasonable accuracy the complete pattern (which is related reciprocally to channeling, now studied in detail6) but the task is a lengthy one which has been completed for very few cases. A many-beam dynamic diffraction calculation of the patterns would be even more difficult and in some cases may be invalid. Because of these complexities, simple methods that will predict to a rough approximation the relative intensities of the lines in films of the back-scattering patterns of a given crystal are wanted. I have found a method which, although it is not a valid computation of intensities or of film darkening by either dynamic or kinematic diffraction principles or by trajectory calculations, nevertheless is found to be useful in practice. It has been tested on several crystal types,7 and is here tested on additional ones. The method consists in first calculating the structure factor F(hk1) for the (hkl) plane, of spacing d, by the familiar equation: where the summation extends over the atoms in the unit cell and fj is the atom scattering factor of the jth atom (using tables computed for electron diffraction, preferably those computed without exchange). Then the F values are squared and summed over all the orders, n, for which F2 has an appreciable value, giving a quantity: Finally, I, is expressed as a percentage of Ic for the

Jan 1, 1970

By John Reynders

Our entry into the World War suddenly brought home to us in a startling way the vital importance of manganese. Since the war, much has been written and said upon the subject of manganese and a great deal of time and money have been spent in attempts to find an adequate substitute for this metal in the manufacture of steel; none has been found. It is true that ways are known by which it is possible to make small amounts of good steel without manganese; but taking into consideration the diminishing quality of iron ores and fuels. as' well as the increasing exaction of specifications for finished products, it may safely be assumed that high-grade manganese ore will be more and. more a necessity in the production of steel as time goes on. Taking world resources as a whole it may be well to point out that the problem of obtaining needed supplies of manganese from a strictly commercial viewpoint is now less serious than it was before the war. Formerly it was feared that world resources of high-grade manganese ore might be exhausted in a relatively short time, but, largely as a result of the stress laid upon the importance of manganese during the war, the world's available supply of high-grade manganese ore has been greatly augmented by new discoveries and fuller development of previously known deposits.

Jan 5, 1927

By Oscar M. Kucus

In January and February of the current year, at the Tooele plant of the hternational Smelting Co., Tooele, Utah, a modification of the usual method of converting, for the treatment of copper-lead matte from lead blast furnaces, was developed and put into successful operation. In brief, the method consists in blowing molten matte direct from the blast furnaces in basic-lined converters, without the addition of siliceous fluxing ores, to the almost complete elimination of the lead contained, and to the production of copper bullion, the resulting lead fume being recovered by the filtration of the converter gases through woolen fume bags. The process is carried out in conjunction with the converting of rever-beratory copper matte, the heavy iron slag, together with the copper precipitated, being transferred to converters blowing copper matte. The purpose of this transfer is to reduce the copper oxide formed, due to the necessary overblowing of the lead-matte charge, and to utilize, as far as possible, the value of iron from the lead matte, for the fluxing of siliceous dry ores. The final slag from the copper converters is then skimmed off and transferred molten to a reverberatory smelting furnace treating copper ores. This variation from general converting practice was the outgrowth of results obtained during 1913 when it was endeavored to convert copper-lead matte in the usual manner, with the direct addition of siliceous fluxing ores. To make clear the reasons lying back of the process it is necessary to recount at some length the results of operations during that year. In the design of the lead plant it mas planned to treat the copper-lead matte from the furnaces by direct converting without reconcentration and thereby to recover the copper, silver, and gold as quickly as possible. A converter plant of ample capacity, treating copper matte, already being in operation, it was only necessary to install a bag house, a fan, and the necessary flues to complete the equipment. The bag house constructed has a bag-cloth filtering area of 136,000 sq. ft., provided by 960 fume bags, 18 in. in diameter by 30 ft. in length. A No. 20 Sirocco fan of 180,000 cu. ft. capacity delivers the gases from

Jan 1, 1915

By Peter M. Anderson

IN recent years many prophets have arisen who hold that gold has outlived its days and that its monetary use is now an anachronism. These prophets include well-known politicians, economists and businessmen. Some of them have called it a joke that metal should be dug up at heavy cost in Africa and elsewhere and shipped to the United States of America only to go underground again at Fort Knox. Others have claimed that all the gold in the world could be sunk in the ocean without anyone being the poorer. The fact that you have invited me to address you on the future of gold may perhaps reflect the fears caused by these various predictions. At present the prophets' taunts show no sign of coming true. The demand for gold is greater than ever before, although stocks held are the largest in history. Nearly all governments have gone to great lengths to suppress any demand that might be made by the public; they have reserved to themselves the right to hold gold and have lost no opportunity of satisfying their own demands. Where the public has been allowed to buy gold, the demand has proved impressively strong. In India the price of gold equals about $82 per fine ounce, having been $90 earlier in the year; in Egypt $65 to $70, after having been $87, and elsewhere it is even higher. In Palestine, for instance, the golden sovereign is traded at about £5, equivalent to $86 per fine ounce, having been nearly £6, equivalent to some $100 per fine ounce, earlier in

Jan 1, 1947

By E. C. Pechin

AT the September meeting of the Iron and Steel Institute of Great Britain, Mr. Charles Wood, of the Tees Iron-works, read an interesting paper on "Further Improvements in Blast-Furnace Hearths," which was followed by an animated and instructive dis¬cussion. If the durability of hearths and in-walls is a matter of interest in England, where furnaces stay in blast from eight to twenty years, it

Jan 1, 1876