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By George Boulter

Draglines 8.2-1 Introduction. The nature and characteristics of rock and rock derivatives forming the crust of the earth vary so greatly from place to place that it is impossible to use the same numerical factors to show the, productive ability of excavating equipment on different jobs or projects. Factors for each project must be developed individually and applied as the conditions and requirements dictate. TYPES' OF DRAGLINES. Types of draglines are differentiated by the propelling method used and are generally divided into four classes, as follows: 1. Wagon mounted 3. Crawler mounted 2. Truck mounted 4. Walking Figure 8.2-1 shows a truck-mounted dragline. This type is considered to be the most mobile unit. In order to increase stability over the side, outriggers are installed as part of the truck chassis. This feature is not shown in .this figure. Figure 8.2-2 shows a crawler-mounted dragline. The long, wide crawlers are used to increase the stability and reduce the bearing pressure of this unit. These features allow for use of these units on surfaces too soft for the wagon- or truck-mounted types. Figure 8.2-3 shows a walking-type dragline. The large diameter tub and the well-supported boom through the gantry gives high stability for rugged works over a long life. BASIC PARTS OF A DRAGLINE. The basic parts of a dragline are illustrated in Fig. 8.2-4. A deck layout is shown in Fig. 8.2-5 with the main components named. OPERATION OF A DRAGLINE. Following is a description of the steps and controls present in a typical cycle of operation of a large dragline having independent hoist and drag motors. Starting the cycle with positioning the bucket on the ground under the point of the boom, the next step is

Jan 1, 1968

By AIME AIME

DURING my senior year at college a professor said to his class that a student who failed to obtain a passing grade in that certain subject could not graduate with his class and that his diploma would be withheld until the failure had been removed. In that way for four years a diploma had been made to appear to us as the objective in attending college. We grew up to think that a diploma was the means of providing employment; consequently, a diploma could not be jeopardized and, heeding the professor's remarks, we resolved to put forth special efforts and make good. During one of our class periods this same professor digressed briefly from his prepared lecture in metallurgy and advised the boys to join a national technical society. He spoke with earnestness and sincerity. After class we students discussed those remarks. We concluded that the professor had not convinced us. We were already members of technical societies at school and saw no need of joining another. In fact, even up to that moment a society had never indicated to any of us that joining it had any relation to landing a job, and we were fully aware that joining another society meant paying out more money, for fees and dues, which money we then needed to buy food, clothes, and perhaps a new slide rule. Furthermore, we knew that joining a society was not part of the curriculum and, therefore, the diploma could not be withheld if we did not follow the advice. Our conclusion was that we would not join but would concentrate on our work that assured getting our diplomas.

Jan 1, 1936

By Haakon Styri

In discussion of Dr. Fitterer's paper on electrolytic separation of slag inclusions, some results from experiments on electrolyzing high-carbon steels at the SKF Research Laboratory were given. l We had been working for a number of years on chemical methods of separating the inclusions but could not find any solvent that would dissolve the steel without attacking some of the inclusions, particularly the sulfides in which we were mostly interested at the time, nor any that would dissolve all sulfide or silica in filings as fine as 300 mesh without attacking the iron. Electrolytic methods had also been tried without any real progress until we learned from the Bureau of Mines about the use of the collodion membrane around the anode. Our early difficulties were to some extent different from those of the Bureau of Mines, perhaps because of experimenting on steels of higher carbon content, but most of our difficulties were of the same nature as those of the Bureau. Formation of large quantities of basic hydroxides was traced to the use of impure and oxidized ferrous sulfate. To protect from oxidation from the atmosphere during electrolysis, after purer chemicals were obtained, a thin layer, 54 in. or less, of molten paraffin was poured over the surface of the cathode liquid, where it solidified. It was found desirable also to hold the cathode chamber slightly acid by initial addition of 0.1 per cent acid (sulfuric or hydrochloric) to prevent precipitation of the hydroxide. This acidity would decrease gradually and the cathode chamber would become neutral before the end of the electrolyzing. The increase in acidity in the anode chamber during our early experiments had appeared to cause attack of the precipitated sulfides in the residue, which originally was analyzed by volumetric method for sulfur, and for this reason a 10 per cent sodium citrate solution was substituted for the sulfate in the anode chamber. With the use of the more reliable Eschka method for sulfur determination (as in coke), there was however no serious attack on the sulfides in the anode chamber with a variety of different liquids, as shown in Tables 2 and 4. The Eschka method gives a higher sulfur value than

Jan 1, 1933

By J. D. McBeth, G. M. Potter, Ramon Pizarro

Heap leaching is used by the Carlin Gold Mining Co., Carlin, Nev., to supplement conventional processing of gold ore by agitation-leaching and countercurrent decantation. Selected open-pit ore containing about 0.072 oz Au per ton is crushed to 3/4 inch, dumped by truck on an asphalt pad, and leached by sprinkling with dilute cyanide solution for 7 days. The heap is then drained and removed by front-end loader to tailings disposal. About 70 percent of the gold is dissolved. Leach solution from the heap joins the pregnant solution from countercurrent decantation for gold recovery by zinc precipitation. Four leach pads, each with a capacity of 1,400 tons of ore, are in use. About 10,000 tons of ore are heap leached monthly from about April through October. Heap leaching is recessed during freezing weather. Labor, equipment, and reagent requirements for heap leaching are presented.

Jan 1, 1974

By C. S. Matthews, H. M. Girner, C. D. Williams, M. J. Edwardson, H. R. Parkison

Quantitative interpretation of electric logs requires knowledge of formation temperature. In this paper, methods are developed for computing changes in formation temperature caused by circulation of mud during drilling operations. The basis of the method is the mathematical solution of the differential equation of heat conduction. The solution of this equation is presented in a series of graphs. These graphs are used to determine formation temperature disturbance at various radii for arbitrary mud circulation histories. Example comparisons with field results show reasonable agreement. It is concluded that, in general, the temperature disturbances caused by circulating mud are small beyond 10 ft from the wellbore but are quite significant near the wellbore. INTRODUCTION Quantitative interpretation of electric logs requires knowledge of the formation temperature in order to establish the resistivity of the formation water with accuracy. To determine the formation temperature, the temperature disturbances produced by circulating drilling mud must be evaluated. -The objective of this investigation was to develop a method for the numerical determination of these temperature disturbances at any distance from the wellbore as a function of time. The first step was to solve the differential equation describing the temperature behavior in the formation during and after mud circulation. This solution was used to calculate a series of curves relating temperature disturbance to shut-in time for various circulating periods. An "exact" method for computing formation temperatures with the use of these temperature-disturbance plots is described, and the results of an application of this method to a well in Montana are presented. Procedures for approximating formation temperatures are also discussed. BASIC EQUATIONS AND ASSUMPTIONS With the assumptions that (1) cylindrical symmetry exists, with the borehole as the axis, (2) heat flow is 1. The formation can be treated as though it is radially infinite and homogeneous in extent, as regards heat flow. 2. The presence of mud cake can be disregarded. 3. The effect of heat generated by bit action is negligible. 4. After mud circulation ceases, the rate of radial heat flow at the wellbore is negligible and is assumed zero for purposes of calculating temperature change with time. These assumptions are believed to be reasonable because of the agreement achieved between calculated and measured borehole temperature in a well, to be discussed later. Further, the agreement at the wellbore indicates that temperatures in the formation were also approximately correct. since it is the formation temperatures that determine wellbore temperature after ceasing circulations SOLUTION OF THE DIFFERENTIAL EQUATION AND ITS APPLICATION The solution of Eq. 2 for the temperature behavior during and after a single period of mud circulation is

By C. H. Li, R. J. Stokes, T. L. Johnston

Dislocation half-loops, artificially introduced by sprinkling with carborundum, were subjected to stress using three-point loading. The different stages of loop expansion and multiplication were then correlated with the macroscopic stress-deflection curve. Loop expansion started at approximately one-third of the "yield stress," defined here as the motivation stress. Above one-half of the "yield stress" simple multiplication commenced while about two-thirds of the yield stress gross multiplication developed short slip-line segments. These values were not affected by the age of surfaces exposed to both dry and wet air. Slip was not detected on unsprinkled crystals below two-thirds of the "yield stress." Thus the stress to activate intrinsic sources, defined here as the activation stress, was approximately twice the motivation stress. This relationship was independent of the strain rate used. It is concluded that lattice resistance takes the form of a viscous drag rather than a static type of force. THE importance of surface condition and environment as one of the more significant factors controlling the mechanical properties of ionic solids has recently received renewed attention.1-4 In some materials, notably the alkali halides, exposing freshly cleaved specimens to the atmosphere results in a progressive hardening and embrittlement of the crystals. This has been attributed to the surface layer becoming "aged," thereby restricting the motion of dislocations in such a way that pileup and eventually fracture results. It is necessary therefore in studying the mechanical properties of ionic crystals to inquire first into the density and distribution of dislocations in the normal cleaved surface and to understand the role these dislocations play in the onset of plastic flow. Knowledge of the effect of environment on this behavior will then assist in understanding the mechanism of embrittlement on aging. In the work reported here a method is described for studying the initiation of plastic flow from dislocation sources in the surface of magnesium oxide crystals. Preliminary results are described of the influence of surface age on this behavior. EXPERIMENTAL TECHNIQUES The magnesium oxide used in this investigation was obtained from the Norton Co. and had a nominal purity of 99.5.pct. Single-crystal specimens, having dimensions typically 1/4 by 1/8 in. cross section and 1 in. in length, were prepared by cleavage over (100) planes from the parent crystal. They were deformed under three-point loading with 3/4 in. spacing between the two end supports and a constant rate of deflection at the center of 0.001 in. per min. The maximum strain rate therefore was 1.5 X 10-5 sec-1. Reasons for choosing this particular form of loading will become apparent in a later section. In addition, a number of confirmatory type tests have been performed at higher loading rates where the maximum strain rate was increased to 1 x 10-3 sec -1. Following deformation the crystals were etched to reveal the dislocation distribution. In a previous paper5 we described a satisfactory etching solution consisting of 5 parts of saturated ammonium chloride, one part of sulfuric acid, and one part distilled water. Immersion of the crystals for 1/4 hr at room temperature developed reproducible conical etch pits at the points where dislocations emerged through the surface. It should be mentioned that dislocations freshly introduced by room temperature deformation gave sharply pointed etch pits which generally distinguished them from the almost flat-bottomed pits obtained on "grown-in" dislocations. The distinction is obvious in the photomicrograph included in Fig. 5(b). Annealing crystals at 1000°C for 12 hr on the other hand gave sharper etch pits on the grown-in dislocations and the distinction was no lower -possible; a similar observation has been reported for lithium fluoride. We have succeeded furthermore in chemically polishing magnesium-oxide crystals. Boiling in fresh 85 pct ortho-phosphoric acid for only 1 min resulted in a microscopically smooth surface which could again be etched to reexamine the dislocation distribution. This boiling time was sufficient to remove the surface damage introduced by cleavage (see next section). SURFACE DISLOCATION SOURCES There are a number of ways by which dislocations may be introduced into cleaved surfaces to act later

Jan 1, 1960

By R. G. Lazzell

THE British are worried about the postwar possibilities of their coal mining industry. Indeed, there are causes for this worry, with the aver- age 1943 cost of production at about $5.40 per long ton, compared to $3.20 in 1938. Average production per man day has dropped from 1.12 in 1938 to 1.03 long tons in 1943. As a comparison, production per man day in the United States is approximately 5 long tons. The average day wage in the British mines is now a little aver $4; in 1938 the average day wage was about $2.25. Great Britain produced 227 million long tons in 1938 from their deep mines, and in 1943 production was 194.5 million, with an additional 4.5 million from strip mines. To meet present wartime needs, output is being supplemented by the production of strip- mined coal, an industry that did not exist prior to the war. Strip mining is now producing at the rate of 15 million long tons per year.

Jan 1, 1944

Report of the Secretary TO THE BOARD OF DIRECTORS AND THE MEMBERS OF THE AMERICAN INSTI¬TUTE OF MINING AND METALLURGICAL ENGINEERS GENTLEMEN As will be shown by the special reports of the Finance, Membership, Library, Papers and Publications, Increase of Membership, and other standing Committees, together with that of the Treasurer, the year 1927 was one in which the Institute made very satisfactory progress in a number of directions. In total numbers the membership is no larger but in revenue from dues there has been a marked increase. This has been due to the promotion to full membership of Junior Associates of earlier years, to the larger proportion that come in originally as members rather than juniors, and to the keener interest in the work of the Institute reflected in prompter payment of dues. The latter is important, since experience shows that of those who fall behind a large number must ultimately be dropped for non-payment. Conditions in the mining in¬dustries have been healthy though not booming. It has been much easier for members to find employment and meet their financial obligations but there has not been that flow of young men into mining, and hence in part into the Institute, that characterized certain earlier years. Rather the tendency toward centralization and larger industrial units has re¬stricted the number, though not the scope, of opportunities for technical men in the mineral industries. The Institute is constantly receiving resignations from members crowded out of mining into other lines of activity. On the other hand, those who remain in mining and metal¬lurgy have a greatly increased necessity for information and contacts with technology. A few years ago many superintendents and most foremen were non-technical men. Today the reverse rule obtains and shift bosses and men who occupy even lower positions in industrial units are called upon to know and to apply such an amount of technical knowl¬edge that graduate engineers are the rule rather than the exception. The curious situation has obtained that with a much smaller enrollment of students in the schools of mining and metallurgy there has been at times an actual shortage of young engineers for beginners' jobs. The young men retort that the conditions of employment and pay offered in mining are not equal to those in other lines and, while it is undoubtedly true that the young engineer beginning in mining is able to start under conditions markedly better as to pay, living, and responsibility than did the men who are now leaders, they are required to know much more and have usually spent more in time and money to qualify for their jobs. The whole matter is one which warrants much more attention than has been given to it. For the Institute it is important since the young men

Jan 1, 1923

By C. R. Swarts

The use of compressed air or gas in oil wells for raising crude oil to the surface has, within the last year, become a dominant factor In production engineering. Previous application of this principle was largely confined to oil wells that had been pumping for a considerable length of time. In the Seminole area, the gas-air lift has been applied to wells imniediately after natural flow has ceased and in some cases while the wells were still flowing. This early application of the gas-air lift has been watchcd with intense interest by the petroleum industry, both with respect to methods of application and mechanical installations and to the effects on immediate and ultimate production. Methods of Application The Seminole pool at its inception contained sufficient gas associated with the oil to cause natural flow. As no frce gas was found in the main productive horizon, the Wilcox sand, all the gas present was dissolved in the oil, hence the natural flowing life was short, rarely lasting over 45 days. When natural flow ceased, high fluid levels were common, and as depth and crookedness of holes were obstacles to efficient pumping, the gas-air lift was used almost exclusively in raising the oil to the surface. Because of the high gravity of the oil, 41" A. P. I., and its high gasoline content, and also because of the desire to obtain production before offset wells became productive, quantity of production was the aim of the operators and a method of flow was used whereby this aim could be fulfilled. One of the outstanding features of this method consisted in flowing the wells through the annular space between the tubing and rasing. By this means a greater quantity of fluid could be handled than by flowing through the tubing of the size in ordinary use. Wells that would produce only a few hundred barrels on the pump were by this rnethod made to produce as high as 7000 bbl. on the lift. A few days or wreks of production at that rate meant a large recovery of oil. Casing of 636 in. diameter was commonly used as a production string with a 5 3/16-in. liner set on top of the oil sand. Upset tubing for irtro-

Jan 1, 1928

By E. C. Bohlen, H. l. Burghoff

THE work reported in this paper was carried out to supplement the existing information concerning directional properties and recrystallization textures of annealed brass sheet and strip. These characteristics are of direct interest when the forming and drawing properties of such material are being considered. Among those who have made contributions in this field are Bass and Glocker;1 Bauer, Göler and Sachs;2 Phillips and Samans;3 Pratt;4 Price;5 Cook;6 Richards;7 Brick;8 and Brick and Williamson.9 These investigators have found, in general, that in brass strip that shows directional variations in properties, tensile strength has a minimum value and elongation has a maximum value at 45° to the rolling direction. The most pronounced directional properties have been found in material given the greatest reductions in rolling followed by high annealing temperatures. Recrystallization texture of brass has been variously reported as (113)[112], (001)[100], and a combination of (110)[115] and traces of the primary rolling texture, (110)[112]. The directional studies have been very informative, but actual tests appear to have been confined to material in its final condition. Tests at intermediate stages have received little attention although previous history of some materials has been partly considered. Perhaps the most comprehensive investigation was made by Cook,6 who studied the directional properties of 70-30 brass strip for which the final and penultimate, or next to the last, anneals and the final reductions were varied. He found that, for any given combination of penultimate anneal and final reduction, the tendency toward the development of directional properties was reduced as the temperature of the final anneal was decreased. In addition to drawing cups and making tensile tests of the finished material at various angles to the rolling direction, he measured the frequency and the angles of twins in grains for several specimens. Plots of his twin counts showed directionality for the materials that produced eared cups. TEST MATERIALS AND EQUIPMENT For this investigation, one commercial heat of 68-32 brass was cast in the form of bars for cold-rolling, 13 ½ in. wide and 1 ½ in. thick. The analysis was as follows: 68.83 per cent copper, 0.04 per cent lead, 0.01 per cent iron, 31.12 per cent zinc (by difference). The bars were so processed to the final thickness, 0.020 in., as to obtain on this thickness all possible combinations of the variables listed below except those involving the sequence of 84 per cent penultimate reduction and 84 per cent final reduction: I. Penultimate reductions of 37 per cent, 50 per cent and 84 per cent; 2. Penultimate anneals at 800°, 900°, 1050° and 1200°F.; 3. Final reductions of 37 per cent, 50 per cent, 69 per cent and 84 per cent;

Jan 1, 1942

By William S. Springer

A NEW preparation plant has been put in - operation to treat coal from the recently opened Concord mine, located about 15 miles west of Birmingham, Ala., by the Tennessee Coal, Iron & Railroad Co., a U. S. Steel subsidiary. The mine produces metallurgical grade coking coal from the American seam for use as coke in the company's blast furnaces at the Fairfield and Enseley works. The capacity of the operation is 1000 tons of run-of-mine per hr, approximately half of which is delivered to the by-product coke plant at Fairfield after beneficiation to metallurgical grade. The remaining portion of the mine run is rock and refuse removed during preparation. No boiler coal or other fuels are produced by this mine. Preparation of the coal is done both under- ground and on the surface. The underground primary crushing station removes some tramp iron, and screens and crushes the oversize, most of which is rock, to protect the main slope conveyor. The surface plant consists of a crushing and screening plant, large blending bins, a two- process washing plant, a water clarification and

Jan 1, 1950

By John J. Egan, A. B. Kinzel, Walter Crafts

The demands of the petroleum and chemical industries for steels to be used in pressure vessels and similar structures at artificially low temperatures are continually increasing, and the writing of proper specifications with suitable tests becomes increasingly important. Likewise, the selection of suitable steels for such applications is of increasing concern to the metallurgist. It is generally recognized that highly alloyed steels of the austenitic stainless type retain their properties even at very low temperatures and represent the best technological solution of the low-temperature steel problem. However, in many instances less expensive carbon or low-alloy steels suitable for service within limited temperature ranges are available. The problem thus becomes one of defining the various factors involved in the production and fabrication of these less expensive steels and determining the temperature ranges in which their properties justify engineering application. Most of the applications involve welded structures, and the heat effect of welding as well as the nature of the weld metal are matters of prime concern. The first problem that the metallurgist faces is the determination of the type of test to be used as a criterion of the performance of the steel in low-temperature service. It has been generally recognized that the static properties of steel as determined in the ordinary tensile test undergo a gradual and relatively slight change as the temperature of test is lowered in the range of current interest; i.e., from room temperature to minus 120' C. It is further generally recognized that the behavior of steel under impact involving notch sensitivity is definitely affected at the lower temperatures. While the major subject of this paper is the effect of grain-refining deoxidizers, of low-alloy additions and of welding on the low-temperature notched-bar impact properties, an inquiry into the general behavior of steel under low-temperature impact testing is included. This is a pertinent portion of the investigation and the results thereof are

Jan 1, 1937

By Verne D. Johnston

ALTHOUGH the stocks of Lake Superior iron ore on dock or at furnaces at the beginning of the year were about 6,000,000 tons less than at the beginning of 1938, the steel industry was operating at only 52 1/2 per cent of capacity and continued at approximately this rate to about Aug. 1. Consequently the iron mines in the Lake Superior district during the winter and spring period were almost all on a curtailed production basis, governed mostly by the needs of the communities rather than by anticipation of ore demands. Many of these properties gave extra employment by prosecuting heavy strip- ping programs, and the underground mines by shaft sinking and rock development. All underground mines re- turned to full operation in September, mostly two-shift, five days per week. A few operated the sixth day. The ship- ping schedules were increased so that the actual delivery for the year exceeded early expectations by about 20 per cent. Final Lake shipments were slightly in excess of 45,000,000 gross tons.

Jan 1, 1940

By David J. Mack, Dennis R. O’Boyle

The mechanical properties of three polycrystalline intermediale Phases that have the y bvass structure were measured in compression between 400° and 900°K. At the lower testing temperatures— termed Region I— no plaslic deformalion occurred prior to brittle fracture. A1 higher temperatuves— lermed Region III—the three phases deformted plaslically for all strain rules from 1.5 to 36.0 x 10-4 sec-1. The homologous temperature for the inilialion of plaslic flow increased in the same order as tile atomic size difference between atoms in each plmse (0.50Tmp for y AgZn, 0.62Tmp for y CuZn, and 0.76 Tmp for y CuCd). The increased flow resistance oj. y CuCd above 0.50Tmp is explaitzed in terms of the more random arrangement of copper and cadmiwn atoms on the laltice sites of&apos; the y bvass slrilctlire. Plaslic deformation of the three intevmiediate phases in the smooth plaslic flow region appears to be controlled by oacancy-induced dislocation climb. RESULTS are reported in this paper on the mechanical properties of three binary intermediate phases having the complex cubic y brass structure (D82, 143m) containing fifty-two atoms in the unit cell. The structure of the prototype y brass phase, y CuZn, was first analyzed by Bradley and Thewlis&apos; based on the X-ray work of Westgren and Phragmen.2 The y brass structure can be visualized as an arrangement of twenty-seven body centered cubes (3 by 3 by 3) into a unit cell containing fifty-four atoms. From this cell the center atom and the four corner atoms are removed and the remaining fifty-two atoms are slightly displaced, resulting in the y brass structure. Approximately thirty-five binary intermediate phases that have an electron to atom ratio of 21:13 have been reported to form the y brass structure. The three y brass intermediate phases selected for this study are formed from elements in groups IB and IIB of the first and second long period. Each compound exists over a composition range that includes the stoi-chiometric composition A5BB (Cu5Zn8, Ag5Zn8, Cu5Cd8). y CuZn (a0 = 9.944A) has solubility limits extending from 57 to 67 at. pct Zn at 500°C apd melts peritecti-cally at 834°C; y AgZn (a0 = 9.326A) has a solubility range from 58 to 63 at. pct Za and melts peritectically at 661°C. y CuCd (a, = 9.596A) melts congruently at 563°C and has a maximum range of solubility extending from 58 to 64 at. pct Cd. In order to minimize coring and microporosity during solidification, the composi- tion of the compounds that form peritectically (y CuZn and y AgZn) was chosen so that the temperature difference between the liquidus and the solidus is only a few degrees centigrade. In selecting y brass compounds for this study, phases were avoided that contained a transition element or that had an electron to atom ratio greater than 1.70. Hume-Rothery et a1.3 has observed that, when the electron to atom ratio of y brass intermediate phases exceeds 1.70, atoms begin to drop out of the unit cell to maintain a constant electron to unit cell ratio. EXPERIMENTAL PROCEDURE Each of the three intermediate phases was prepared from elements having a purity >99.999 pct. Only trace quantities of impurities (<0.0001 pct) were detected by spectrographic analysis of the four elements. A master alloy of each compound weighing approximately 130 g was prepared by melting the elements in evacuated sealed quartz tubes heated in an electric furnace. Specimens having the desired diameter for the mechanical property measurements were obtained by remelting the master alloy in a Vycor tube under argon and drawing specimens from the melt into 4-mm-diam quartz tubes. To obtain a smooth surface on specimens drawn from the melt, the inside of the quartz tube was coated with a thin layer of graphite formed by thermally decompositing acetone. All specimens were imbedded in sealing wax and cut to the proper length with a diamond-impregnated cut-off wheel. The individual specimens (4 mm diam by 8 mm long) were then sealed in evacuated Pyrex tubes and homogenized at 500°C for 72 hr. Chemical composition, variations over the length of the rod (10 cm long) were generally less than 0.2 pct and the analyzed composition differed from the desired composition by less than 0.5 pct.4 Metallographic evaluation of the specimens after homogenization showed no evidence of a second phase in any of the compounds. The average grain size of the specimens after homogenization was 1 to 2 mm. All mechanical property measurements were carried out in an argon atmosphere using a compression apparatus described previously.5 Prior to applying the load to the specimen, the test apparatus was evacuated, back-filled with argon, and heated to the test temperature for 20 min to establish thermal equilibrium. EXPERIMENTAL RESULTS Mechanical properties measured as a function of temperature and strain rate for each of the three y brass phases were similar. From room temperature to the ductile-to-brittle transition temperature, only elastic deformation was observed prior to fracture.

Jan 1, 1968

By ARTHUR THACHER

PRIMITIVE man supplied his wants as they arose; as he became more civilized he anticipated them by producing more regularly and storing the products for future use. This tended to cheapen&apos; production and prevent &apos; violent fluctuations and therefore tended to increase consumption. In order to anticipate our wants, we must know what these wants will be, and this can be .determined only by statistics. &apos;While we have made great progress in gathering statistics, they are still far from what they should be; especially metal statistics. We determine fairly, well the amount produced, but this does not answer all inquiries because of the erratic conditions of mining, it is necessary to carry larger stocks of metals than of most other articles; moreover, as metals are more or less durable, it is difficult to determine the actual consumption. We often count under consumption what is being produced and sold, while the actual consumption is what is being worn out.

Jan 1, 1921

By Joseph E. Pogue

NEW economic forces are at work in the petroleum industry.. In order to visualize these forces and clearly see their bearing on the producer, refiner and marketer, it is necessary to see in perspective the economic evolution of the business. For several decades prior to 1913 the outstanding feature of the petroleum industry was a trend toward integration, culminating in a huge combine, the Standard Oil Co. An important aspect of this integrative trend, however, was its concentration on the combination aid control of refining and marketing, leaving crude oil production, for the most part, to the exigencies. of small-unit competition. It is a noteworthy coincidence that during this era the law of oil and gas was formulated and applied, whereby these substances had to be reduced to possession to establish ownership; and the forces of competition in crude oil production were thereby intensified. It was to the interest of an industry, safeguarded in its control of manufacturing and markets, to have supply stimulated by legal convention as well as by individual initiative in order that the growing demand could be met without interruption. And so over-production of crude oil during this era was no handicap, but rather an aid, to the progress of the industry.

Jan 1, 1929

By C. B. Alcock, M. G. Hocking

The kinetics of the growth of sulfate layers on blocks of Cu20 has been studied between 688" and 800°C. At 788c the over-all weight increases followed the parabolic rate law, with k = 216 30 sq mg per cm4 min, using a 1:1 entering gas mixture of SO2:02. At 757 after an initial linear period the parabolic rate law was followed, with k = 57.8 10 sq mg per cm4 min. The gas mixture required a platinum catalyst to produce the maximum SOs pressure. The sulfation rate at 757&apos; and 788c was high until all the CUZO had changed into a core of CuO, when it became very much lower. At 757°C marker experiments showed that the sulfates (CuO. CuS04 and CuSO4) grow outwards from the oxide surface, but CuO. CuS04 mixed with CuO was found beneath the markers. At 688 markers were found at the CuO. CuS04/CuS04 interface. Visual observations at 757 showed a liquid eutectic moving beneath the sulfate surface. causing very rapid sulfation and extruding to solidify as thick &apos;needles" up to 8 mm long. Marker experiments have shown conclusi.cely that CuO grows on Cu20 in air by the outward migration of copper. ThermODYNAMIC measurements on the sulfate and basic sulfate of copper, reported recently,&apos; are followed here by measurements of the rates of formation of these sulfates on cuprous oxide, in order to provide a background for the understanding of roasting processes. peretti2 and McCabe and Morgan3 have shown that the phase Cu20 lies next to Cu2S when the sulfide is roasted under conditions where sulfates will be formed. Since this would present too complex a system for kinetic study, the present work4 has been based on the kinetics of sulfation of the oxide phase. The results of a study of the kinetics and mechanism of the sulfation of cobaltous oxide have recently been reported.4,5 Results on the sulfation of cuprous oxide have also appeared,6 but are at variance with those to be reported here. This seems to be because the previous workers6 did not obtain constant SO3 pressures from the SO2/O2 sulfating gas mixtures used, as will be discussed later. Wadsworth, Leiter, Porter, and Lewis found that the sulfates produced when SO2/O2 mixtures are passed over Cu20 at red heats are CuS04 and the basic sulfate CuO.CuSO4. When the decomposition of CuS04 was followed&apos; by differential thermal analysis, a stage corresponding to CuO .CuS04 was reached before decomposition into the oxide occurred. APPARATUS The vertical furnace used for quantitative studies was a conventional resistance-heated and propor- tionately controlled furnace with an even zone (1 deg) which was 4 cm long. The gas mixtures of SO2 and 02 were made by mixing measured flows from capillary flowmeters and drying over phosphorous pentoxide before passing them into the Pyrex top-piece of the furnace assembly. A mullite tube of bore 2% cm was used as reaction vessel and at the bottom of this tube was a trap for SO3, which condensed as a colorless liquid. The residual gas was led into a fume cupboard for ventilation to the atmosphere. The furnace used for visual observations of needle growth and other phenomena consisted of a transparent silica reaction tube of bore 3 cm, having an optically flat silica window sealed into its wall. The reaction tube was clamped vertically, inside a mullite tube of bore 4 cm and length 42 cm which was heated by Kanthal windings. The window in the silica reaction tube was arranged opposite a hole 3 cm wide and 2 cm tall which had been cut in the wall of the mullite winding tube 19 cm from its top end. A binocular microscope was used to look through the window, illumination being provided by a focusing microscope-lamp offset sideways and downwards. The oxide block to be sulfated was suspended from the removable Pyrex top-piece to the reaction tube, by means of which it was inserted at the start of the experiment, and through which entered the S02/02 gas mixture. The variation of the temperature inside the reaction tube with horizontal and vertical displacement from the window was investigated, and, while it can be said that the temperature was constant 1 deg, its value at a given position was known only to 12 deg. In both furnaces, the oxide block to be sulfated was suspended from a small silica hook immediately downstream from a platinum thimble used as catalyst, which was held on a long silica rod from a Pyrex spring attached to the removable Pyrex top-piece of the furnace. The spring was only included in the quantitative sulfating furnace; its sensitivity was 1.4 cm per g and it was found to be free from creep in a 16-hr test when carrying the working load. The extensions were followed by a cathetometer which could be read to 0.001 cm, corresponding to i0.7 mg. Extensions of the spring were measured on adding weights between 5 and 500 mg to the working load (thimble + oxide block), and Hooke&apos;s law was closely obeyed. SAMPLES Cuprous oxide blocks were prepared by oxidizing Johnson Matthey "Specpure" copper sheet of 1 mm thickness (impurities: iron at 3 ppm, silver at 2 ppm, lead, nickel, sodium, and silicon each at 1 ppm, calcium, chromium, magnesium, and manganese each at less than 1 ppm) for 6 days in air at 1000°C in a re-crystallized alumina boat. It has been reported7 that when Cu20 is prepared by heating copper sheet for 1 day the central plane of the blocks produced consists

Jan 1, 1967

By John D. Sullivan

ALUMINUM and magnesium plants in the United States underwent enormous wartime expansion which made many wonder if ghost plants would result when industry swung back to a peacetime basis. Production capacity of primary aluminum ingots was stepped up from 150,000 tons annually to about 1,150,000 tons; magnesium production increased from 2500 tons in 1936 to nearly 200,000 in 1943, with a production capacity of some 300,000 tons. Not only was primary metal production enlarged but also the capacity of prime fabrications such as castings, forgings, extrusions, and sheets was correspondingly increased. In mid-December it was estimated that production of primary aluminum ingots in the United States in 1946 will be about 410,000 tons while consumption will be about 500,000, close to half of the wartime consumption. The 1946 estimated consumption of secondary aluminum is 200,000 tons. The critical shortage of soda ash is hindering production of primary metal, and the outlook for an early relief of this shortage is dark.

Jan 1, 1947

By Harlowe Hardinge

AN extensive recent trip throughout the mining districts of the Southwest, Central West, an Northwest,&apos; reveals a numbes of interesting conditions that have influenced operators, in both large and small mills, to modify their flow sheets insofar as they pertain to crushing and grinding. The changes made and planned for the future should be of interest. It is interesting to note when traveling through the country, how ideas change and practice is modified, and it is rather amusing to see how milling methods seem to run, more or less, in cycles. New ideas and developments are brought about which run through the industry and are taken up by many of the best and most well informed operators. Some of them will change, sooner or later, back to their old practice; for, like everything .else, what will work well in one place will not necessarily be suited to another. On the other hand, it is often difficult to establish. other practices known to be of value, owing to the natural resistance to make a change, but on the whole, the western mill men seem to be more alive to possible benefits of various modifications than any other engineers with whom I have come in contact in all parts of the world. Mill men in other parts of the world always keep in con- tact with what is being done in the western part of the United States, but it does not necessarily follow that those in the western part of the United States are always right. Some of these changes that have been made and afterward abandoned will be referred to later.

Jan 1, 1929

By Ottey M. Bishop, William G. Peryam, Fred E. Johnson

THE Lepanto Consolidated Mining Company is the largest copper producer in the Philippines, and the only one that makes a concentrate valuable principally for its copper; also, it has the only productive copper mine situated at considerable distance from the sea, and is the only one in the islands operating its own smelter. The Lepanto mine is in the Municipal District of Mankayan, sub-province of Benguet, near the heart of the Mountain Province of Northern Luzon. It is 165 km. from its shipping point at San Fernando, Province of La Union, on the shore of the China Sea. Elevations at the property range from 3200 to 4500 ft. The climate is very mild; temperatures are seldom below 50° or above 80°F. Annual rainfall approaches 170 in. and is mainly confined to a rainy season lasting from May to October. The months from December to April, inclusive, are usually extremely dry. This climatic pecularity entails the problems of landslides on the roads during the rainy season and water shortage during the dry season. The Mountain Trail, an improved rocksurfaced toll road maintained by the Commonwealth Government, gives access to the property. The 105 km. over this road may be traveled in about 4 ½ hr. during the dry season. Very few sections of the road are straight for more than 100 meters, and about one third of it is a one-way road controlled by gates. All freight for the property is delivered by the Manila Railroad Company to Bauang, La Union, 45 km. west of Baguio and at sea level, where it is picked up by freight trucks and hauled via Baguio to Lepanto. Granulated matte is hauled in bulk from Lepanto in four-ton lots on freight trucks to the storage bins at San Fernando. Freight rates from Bauang to the property amount to [P]8.oo per ton, and from the property to San Fernando the rate is [P]16.00 per ton. The company pays the road toll, [P] 1.00 per truck, each way. THE CAMP The company maintains a modern camp, well separated from the mine and reduction plant. Comfortable and sanitary living quarters, water, and light, as well as free medical service are provided all employees. A hospital staffed by a doctor and two nurses takes care of all medical treatment. Considering recreational facilities of great importance, the company has provided two tennis courts, two basketball courts, and badminton courts for employees. Bowling alleys and a motion picture theater are operated by the company, the profits being expended for other recreational purposes. A moderate sized recreation hall serves for barrio dances, meetings,

Jan 1, 1942