Search Documents

[Contents AH-Metal Mining and Industrial Minerals Pipeline Transportation of Phosphate. (Paper by I. S. Tillotson, R. B. Burt, and J. A. Barr, Transactions AIME, 193, 273; Mining Engineering. March 1952. Discussion by Howard Howie.) 1066 B-Minerals Beneficiation The Effect of Zinc Deleading Operations on Lead-Zinc Selectivity at the Parral and Santa Barbara Mines. (Paper by C. L. Boeke an G. C. Gunther, Transactions AIME, 193, 495; Mining Engineering. May 1952. Discussion by I. M. Symonds, L. H. Lange, Norman Weiss, H. S. Wildman, C. F. Zeuch, E. H. Crabtree.) 1067 Jaw Crusher Capacities, Blake and Single-Toggle or Overhead Eccentric Types. (Paper by D. H. Gieskieng, Transactions AIME, 190, 971; Mining Engineering. November 1951. Author s supplement.) 1069 Screened Ore Use for Fine Grinding at Lake Shore Mines. (Paper by Bunting S. Crocker, Transactions AIME, 193, 499; Mining Engineering. May 1952. Discussion by Fred C. Bond, J. Myers, Norman Weiss, Harlowe Hardinge, Oscar Johnson, L. E. Djingheuzian.) 1069 The Third Theory of Comminution. (Paper by Fred C. Bond, Transactions AIME, 193, 484; Mining Engineering. May 1952. Discussion by Milton C. Shaw and Donald R. Walker; R. J. Russell.)1071 Flotation Rates and Flotation Efficiency.t (Paper by Nathaniel Arbiter, Transactions AIME, 190, 791; Mining Engineering. September 1951. Discussion by Gregoire Gutzeit and Porter Clements.) 1074]

Jan 1, 1952

By Horace V. Winchell

The laws here referred to are those which define the status of the prospector for mineral deposits in the soil or beneath it, establish his methods of procedure, protect him in his possession while searching for the subterranean treasures, and give him assurance of title when all required conditions have been fulfilled and valuable minerals discovered. Regulations for the operation of mines and the safety and health of mine employees are likewise subjects of Federal and State legislation, but are not within the scope of the present program. Various features of our present laws will be discussed in detail by able students of the subject, and specific remedies will be proposed for the most glaring defects. It is my purpose to present in this paper a summary review of the reasons why revision is needed and demanded by the great majority of those in daily contact with the industry. Reason Number One The first objection to the continuance of the present law is that it was not planned by its framers and the Congress which passed it to apply to many of the kinds of mineral deposits, nor to the mining conditions, which are controlled by it to-day. In 1866, under the title, "An Act granting the right of way to ditch and canal owners over the public lands, and for other purposes," was surreptitiously smuggled into existence our first mining law (14 Stats. at Large, Chap. 262, p. 251). This law provided that "whenever any person or association of persons claim a vein or lode of quartz or other rock in place, bearing gold, silver, cinnabar or copper, having previously occupied and improved the same according to the local customs or rules of miners in the district where the same is situated," etc., a patent might be granted an certain conditions. This was evidently an Act intended to validate claims already initiated, and to accord Federal recognition to mining locations made in

Jan 1, 1915

THE problem of reaction rates in the open-hearth process is essentially that of trying to form a fairly clear picture of the "chemical mechanisms" in the bath. Quantitative data on reaction rates would not be very useful even if they were available; however, what few , approximate data there are, can be used in combination with data given in Chapters XVI and XVII to sketch a picture of the "chemical mechanics" of the open-hearth process that is consistent with essentially all the present available evidence. The result may later be found incorrect in many details but even so it will illustrate certain useful methods for obtaining a clearer understanding of the process. As discussed in the last portion of Chapter XIII chemical reactions in general involve the following factors: 1. The reacting molecules are mixed together in space in such fashion as to favor collisions among them. 2. A certain number of collisions occur per unit time among the reagent molecules, depending on their concentration and on temperature. 3. A certain percentage of these collisions result in reaction, these being the collisions between those molecules possessing at the moment energy levels above certain minimum values. The temperature factor enters mainly through (3), and its effect is very marked. (What is called temperature is really the mean energy content of all the molecules of the substance involved; at any one temperature a certain proportion of the molecules will have much higher energy content than the mean value.) Various reaction rates measured at around room temperatures have been found to be speeded from 1.6 to 4.0 times by an increase of only 15 to 20°F., simply because increasing temperature produces a rapidly increasing percentage of molecules with energy levels above the minimum needed to produce chemical reaction in a collision.

Jan 1, 1944

Abbey, Robert Graham, District Mgr.. The W. W. Sly Mfg. Co., 50 Church St.. New York, N. Y. '21 Abbott, A. N., Mines Supt., Mazapil Copper Co., Ltd Concepcion del Oro, Zac., Mexico. '28 Abbott, Argyle Campbell, Dev. Dept., E. I. du Pont de Nemours & Co., Wilmington, Del. '29 Abbott, Clarence E., V.P., Charge of Raw Materials, Tenn. Coal, Iron & R. R. Co., 1242 Brown-Marx Bldg.. Birmingham, Ala. '04 Abbott, Louis Benjamin, Chief Engr., Elkhorn Div., Consolidation Coal Co., Jenkins, Ky. '16 Abeel, George H., Jr., Cons. Min. Engr Box 427, Santa Monica, Cal. '18 Abel, Albert E., Asst. to Pres., Valley Mould & Iron Corp Hubbard, Ohio. '19 Abel, Raymond L., Asst. Prof., Dept. of Pet. Refin., Univ. of Pittsburgh Pittsburgh. Pa. '28 Abeel, Leo M., Research Engr., Sullivan Concentrator Chapman Camp, B. C., Canada. '31

Jan 1, 1932

By I. R. Kramer

Studies of the effect of size of the specimen on the change of slopes of Stages I and 11 by surface removal showed that the change of Stage I was independent of size with respect to the polishing rate; however, the change in the slope of Stage 11 with polishing rate increased directly in proportion to the surface area. The removal of the surface during the test affected the plastic deformation characteristics of gold, aluminum, and zinc single crystals and polycrystalline aluminum. The apparent activation energy of aluminum was found to be decreased markedly by removing the surface during the deformation process. In previous papers1-3 it was shown that the surface played an important role in the plastic deformation of metals. By removing the surface layers of a crystal of aluminum by electrolytic polishing during tensile deformation, it was found that the slopes of Stages I, II, and III were decreased and the extents of Stages I and II were increased when the rate of metal removal was increased. By removing a sufficient amount of the surface layer after a specimen had been deformed into the Stage I region, upon reloading, the flow stress was the same as the original critical resolved shear stress and the extent of Stage I was the same as if the specimen had not been deformed previously. The slope of Stage I was decreased 50 pct and that of Stage 11 decreased 25 pct when the rate of metal removal was 50 X 10"5 ipm. These data show that in Stage I the work hardening is controlled almost entirely by the surface conditions, while in Stages 11 and III both surface conditions and internal obstacles to dislocation motion are important. It appears that during the egress of dislocations from the crystal, a fraction of them becomes stuck or trapped in the surface regions and a layer of a high dislocation concentration is formed. This layer would not only impede the motion of dislocations, but would provide a barrier against which dislocations may pile up. In this case, there will be a stress, opposite to that of the applied stress, imposed on the dislocation source and dislocations moving in the region beyond this layer. It has been found convenient to refer to this layer as a "debris" layer. The "debris" layer may be similar to the dislocation tangle observed by thin-film electron microscope techniques.4 Reported in this paper are the results of studies on the effects of removing the surface during plastic deformation on aluminum crystals of various sizes. The effects of the surface on the yield point behavior of gold and high-purity aluminum crystals as well as the creep behavior were also determined. The effects of surface removal on polycrystalline aluminum (1100-0 and 7075-T6) are also reported. EXPERIMENTAL PROCEDURE For those portions of the investigation involving creep and tensile specimens, single crystals, having a 3-in. gage length and a nominal 1/8-in. sq cross section, were prepared by a modified Bridgman technique using a multiple-cavity graphite mold. The single crystals were prepared from materials which had initial purities of 99.997, 99.999, 99.999, and 99.999 pct for Al, Cu, Zn, and Au, respectively. The aluminum specimens for the size effect studies were prepared through the use of a three-tier mold in which crystals having a cross section of 1/8, 1/4, and 1/2 in. were grown from a common seed. The mold design was arranged so that one 1/2-in. crystal, two 1/4-in. crystals, and four 1/8-in, crystals of the same orientation could be cast. With this technique, it was possible to obtain only one set of crystals with the same orientation. Because of this limitation, it was not possible to determine both the changes of extent and slope of the various stages since a large number of crystals of the same orientation would have been required. Instead, only the change of slope as a function of the rate of metal removal was studied by abruptly altering the current density of the electrolytic polishing bath at various strains within the regions of Stages I and 11. The experimental techniques used for the tensile studies were essentially the same as those used previously.1,3 The specimens were deformed in a 200-lb Instron tensile machine, usually at a rate of 10-5 sec-5. A methyl alcohol-nitric acid solution was used as the polishing bath for aluminum. The temperature was maintained constant within ±0.l°C by means of a water bath. The tensile machine was

Jan 1, 1963

By Paul Tyler

THE ferroalloying elements are connecting links between the steel industry and the nonferrous metal industries. Although ferroalloys are distinctly nonferrous themselves, they serve the steel industry either in the manufacturing process or in modifying the product-in some cases so that it may compete in the markets with nonferrous metals. Of the 92 elements generally accepted by chemists as constituting the primary building blocks of matter, all but the very rarest have been investigated with a view to employing them in steel manufacture. The surprising thing is that so few have been found commercially acceptable. Despite the relatively small number of elements involved, the employ-ment of alloys in steelmaking is one of the most complicated and probably one of the least well understood of modern industrial enterprises. A great deal has been written regarding the action of individual elements and a profuse and somewhat acrimonious literature covers pretty much the whole field of ferroalloy ore supplies. In the middle ground between the miner and the steelmaker developments are less carefully watched by most observers, and except for an occasional description of the technique of some conversion process or the tariff hearings in Congress, very little is said about them. The purpose of the present paper is to describe in relatively nontechnical terms this highly complex industry and to study its relations to our national progress.

Jan 1, 1933

By Raymond D. Sloan

During 1944, substantial gains were recorded in practically every phase of the petroleum industry in Oklahoma. With the spotlight of activity focused on other states during the more recent years, the production momentum that was achieved in Oklahoma through the discovery and development of such outstanding pools as Oklahoma City, Fitts. and major pools in the Seminole area during the late 1920's and early 1930's was practically spent by the end of 1943. However, with much of the industry's exploratory efforts greatly reduced in Illinois, Indiana and Kentucky, the strong demand for Mid-Continent crude and the optimism created by some discoveries in the state toward the end of 1943, Oklahoma has again become the recipient of much activity and interest, with its 1944 drilling activity, production and refinery runs to stills registering substantial gains over the preceding year. Development and Exploration Since the discovery of the West Edmond pool in April of 1943, with the substquent drilling and development boom, the scene of exploratory activity has shifted from the central. south and east portions of the state to the general trend of the . Granite Ridge, where leasillg and wild-catting were greatly activated within a wide radius of this high subsurface feature. Leasing activity, however, jumped the confines of the Granite Ridge trend and extended into all of the northwestern counties in the state. Seismograph activity at once began following and keeping pace with this shift in the leasing and exploration locale, by the concentration of a large number of seismograph crews in the area. At one time during the year,35 crews were concentrated in Oklahoma, the majority being west of the Granite Ridge and extending into the northwestern counties. To illustrate the increase in geophysical work done in the state during the year, records indicate that 377 crew months were worked in 1944, which is a 21 per cent increase over the 311.5 crew months activated in 1943. With the discovery in 1943 of several encouraging prospects and the finding of West Edmond as an incentive, drilling operations increased some 54.3 per cent, for a total of 1986 completions during the year. This is compared with a figure of 1287 for wells drilled in 1943, an increase of 699 wells. The industry, with a total of 1064 oil producers, enjoyed a success percentage of 53.6 per cent. Gas wells completed were 223, while 699 dry holes were drilled. In 1943, completions included 587 oil wells, 127 gas wells, and 573 dry holes. The number of oil producers completed during the Year was almost double the numher of wells in 1943. Of the total drilling wells completed in the state, 350, or 17.6 per cent, were wildcat operations—an increase of 5.1 per cent over the 194.3 total of 333. The wildcat success percentage was 13.4 per cent, 47 successful wells being completed for an average initial potential of 160 bbl. In the state, 23 gas wells were completed with an average initial production of

Jan 1, 1945

By Gerhard Derge

Metallurgists have used borax as a fluxing agent traditionally, but until recently elemental boron has played an insignificant role as an alloying element. Neither the metal nor its compounds have been regarded as important metallurgical materials and there is a surprising lack of knowledge concerning their metallurgical behavior. The new applications to steel-making of both boron and borates, which arose in part from wartime incentives and restrictions, have been seriously handicapped by this lack of data. For example, rasorite, a naturally occurring sodium borate, has been shown to be an effective substitute for aluminum as a ladle deoxi-dizer in rimming steels.' Likewise, the effectiveness of boron as an alloying agent has been demonstrated,2,3 giving deep hardening when used in restricted amounts. The exploitation of both of these uses has been retarded by the difficulty of attaining suitable metallurgical control. Recognizing that the most important information required was a knowledge of the equilibrium between boron and oxygen dissolved in liquid iron. Gurry4 calculated this relation from the best thermal data available. However, estimates of the entropy of melting of boron, the activity coefficient of boron in liquid iron and the activity coefficient of B2O3 in slag were involved, and experimental work on this problem was obviously desirable. The experiments to be described were planned to establish the boron-oxygen relations in liquid iron and to demonstrate at the same time the ferroborate slag compositions in equilibrium with various amounts of oxygen in liquid iron. Accordingly, slags containing varying proportions of iron and boron oxides were held in contact with molten iron, and samples of both slag and metal were analyzed. The limitations upon the accuracy of the data will be considered, but in a practical sense the oxygen levels that can be attained in iron by iron borate slags, and the amounts of boron in iron at these oxygen levels were established. Experimental Procedure No entirely suitable refractory was found for the mixtures of iron oxide and boron oxide used as slags. Crucibles of silica, magnesia, Ramix, beryllia, and zirconia were all tried unsuccessfully. The must satisfactory method discovered for handling them was the rotating-crucible technique, which creates a parabolic crucible of liquid iron.5,6 Even this was not entirely successful, for at steelmaking temperatures (1600°C.) the slags had such a low surface tension that they crept up to the refractory and slowly dissolved it. These difficulties made it impossible to maintain a constant slag composition for an unlimited period Of time. However, by using the rotating technique, short runs could be made in

Jan 1, 1947

By Gerhard Derge

Metallurgists have used borax as a fluxing agent traditionally, but until recently elemental boron has played an insignificant role as an alloying element. Neither the metal nor its compounds have been regarded as important metallurgical materials and there is a surprising lack of knowledge concerning their metallurgical behavior. The new applications to steel-making of both boron and borates, which arose in part from wartime incentives and restrictions, have been seriously handicapped by this lack of data. For example, rasorite, a naturally occurring sodium borate, has been shown to be an effective substitute for aluminum as a ladle deoxi-dizer in rimming steels.' Likewise, the effectiveness of boron as an alloying agent has been demonstrated,2,3 giving deep hardening when used in restricted amounts. The exploitation of both of these uses has been retarded by the difficulty of attaining suitable metallurgical control. Recognizing that the most important information required was a knowledge of the equilibrium between boron and oxygen dissolved in liquid iron. Gurry4 calculated this relation from the best thermal data available. However, estimates of the entropy of melting of boron, the activity coefficient of boron in liquid iron and the activity coefficient of B2O3 in slag were involved, and experimental work on this problem was obviously desirable. The experiments to be described were planned to establish the boron-oxygen relations in liquid iron and to demonstrate at the same time the ferroborate slag compositions in equilibrium with various amounts of oxygen in liquid iron. Accordingly, slags containing varying proportions of iron and boron oxides were held in contact with molten iron, and samples of both slag and metal were analyzed. The limitations upon the accuracy of the data will be considered, but in a practical sense the oxygen levels that can be attained in iron by iron borate slags, and the amounts of boron in iron at these oxygen levels were established. Experimental Procedure No entirely suitable refractory was found for the mixtures of iron oxide and boron oxide used as slags. Crucibles of silica, magnesia, Ramix, beryllia, and zirconia were all tried unsuccessfully. The must satisfactory method discovered for handling them was the rotating-crucible technique, which creates a parabolic crucible of liquid iron.5,6 Even this was not entirely successful, for at steelmaking temperatures (1600°C.) the slags had such a low surface tension that they crept up to the refractory and slowly dissolved it. These difficulties made it impossible to maintain a constant slag composition for an unlimited period Of time. However, by using the rotating technique, short runs could be made in

Jan 1, 1947

By Walter C. Lawson

The primary objective in laying track in panel sections is to reduce the number of track laborers required. This is possible because the work is mechanized. Moreover, because the work is mechanized and each of the operations needs only a few men, and each is self-contained, the work can be carried on at night as well as in daylight; therefore, the method provides a means of preparing tracks on more than one shift. The laying of tracks in open pits and quarries in panel sections is not new but new methods have been made possible by the introduction of new types of equipment. The purpose of this paper is to describe the methods that are followed in the Morenci open pit. General Mining Operations Full-scale ore production at Morenci is about 50,000 tons daily. The normal yearly output of ore and waste is 32,000,000 tons, of which 30,000,000 tons is handled by rail haulage. This requires the building of approximately 47 miles of loading and other temporary tracks during a 12 months' period (Fig I). Broken ore and waste is loaded into 90-ton capacity dump cars with 5-cu-yd full-revolving electric shovels. Shovel banks are uniformly 50 ft high. They are blasted with churn drill holes and the broken material from a blast is loaded out with two shovel cuts, the first one being called (locally) the "splatter" cut and the second one the "clean-up" or "face-up" cut. When a shovel is making its clean-up cut, the loading track is about 70 ft from the toe of the bank and, under normal conditions, a bank is blasted against it without removing the track. It is thus evident that each track is used for two shovel cuts before relocation is necessary, inasmuch as a single position serves for both the clean-up cut prior to blasting and for the splatter cut following the blast. The normal advance of a solid bench by a single blast is 40 ft (Fig 2). Preparation OF Panel Grade In preparation of panel grades bulldozers and rooters are used for the bulk of the work and an auto-patrol road grader for the final stage. At Morenci, bulldozers have always been used for track-grade preparation, but before the introduction of the other two types of equipment grades were uneven and irregular at best, and always necessitated a big gang of track laborers to hand-block under the ties with rocks after a track was laid into place. High blocking also made poor track because of instability and caused frequent derailments. Under these conditions derailments were generally bad as re-railing became difficult. Much track was torn up and many tics broken in the process. The inadequacy of the hand-blocked track, together with the inefficiency of hand blocking, constantly pointed, to the desirability of reducing the amount of labor required, so various means were tried to improve conditions, such as wood

Jan 1, 1949

By H. J. Levinstein, H. J. Guggenheim, C. D. Capio

An optical incestigation of the phase transformations in RbFeF, has been conducted. Details of the ferromagwetic phase transition and the metamagnetic state are disczrssed. The three-dimensional magnetic domain structure existing in bulk crystals of RbFeF3 is described, as well as the effect of the magnitude and direction of the applied magnetic field on the domain struclure. The strong magnetoelastic interaction in RbFeF, is demonstrated. The results of the direct observation of the role of dislocation subboundaries and slip bands as nucleation sites and as pinning sites for magnetic domain walls are reported. THE perovskite compound RbFeF, has recently been shown to exhibit three magnetic states.''' Above 102°K it is paramagnetic, between 102" and 87°K it is antiferromagnetic. and below 87°K it is ferromagnetic (i.e., exhibiting remanence) with a modification of the magnetization occurring at 40°K. The changes in magnetic structure at 102o, 87°. and 40°K are accompanied by shear transformations to successively lower crystal symmetry classes.3 At 102°K a second-order phase transformation to a tetragonal crystal structure occurs. The c/o ratio increases with decreasing temperature to a value of 1.0034 at 87°K where the crystal undergoes another shear transformation to an ortho-rhombic crystal structure. The magnetic modification at 40 K is also accompanied by a shear transformation to a lower crystal symmetry. RbFeF3 is unique in that in the ferromagnetic state it is transparent in the bulk to visible light, has a low saturation magnetization, a large magnetic rotation. and has good optical properties.' All these features make it an ideal material for the investigation of magnetic domain structures in bulk crystals. In addition a dislocation etch has been developed which reveals the point of emergence of dislocations with the (100) surfaces of RbFeF3,5 making it possible to determine the dislocation arrays in the material. As a result domain wall dislocation interactions can be observed in the bulk crystal. In this paper we report on 1) the crystallography of the phase transformations in RbFeF3. 2) the domain configurations as a function of magnetic field and crystal orientation. 3) the interaction of dislocations and magnetic domain walls in RbFeF,. EXPERIMENTAL PROCEDURE Since the temperature range of interest is below room temperature the dewar shown in Fig. 1 was employed. It was designed to fit on the stage of a Leitz panphot metallograph, and permitted examination of the sample at a magnification up to 150 times. The dewar consists of a double-walled glass cylinder bent into an L shape. The space between the walls is evacuated. The viewing wirldows were made of four optically flat quartz discs aligned parallel to each other and sealed to the sides of the concentric cylinders. The specimens were mounted in a holder attached to a flexible plastic shaft. Various holder designs were employed depending upon the type of observations to be made. For studies of the phase transformation between the antiferromagnetic and ferromagnetic state the holder shown in Fig. 2(d) was employed. This holder permitted accurate temperature control at 82" to 88°K by balancing the heat input from the carbon resistance heater against the heat loss to a heat sink immersed in liquid N2. Magnetic field studies were conducted by employing the holders shown in Figs. 2(a) and (b). The holder shown in Fig. 2(n) has a solenoid imbedded in it. such that the magnetic field direction is in the same direction as the incident light. The magnetic field provided by the holder in Fig. 2(b) is perpendicular to the incident light direction. The holder in Fig. 2(r) was employed when observations of the specimen were desired while an elastic bending stress was applied to the sample. The stress was applied to the sample by pulling a wire from outside of the dewar. The wire was attached to a lever pivoted on the holder. which caused the knife edge of the lever to push against the sample. The crystal growth and the sample preparation were described previously.' PHASE TRANSFORMATIONS The first phase transformation in this system is from the cubic perovskite structure to n tetragonal

Jan 1, 1970

By H. Kazemi

An ideal theoretical model of a naturally fractured reservoir with a uniform fracture distribution, motivated by an earlier model by Warren and Root, has been developed. This model consists of a finite circular reservoir with a centrally located well and two distinct porous regions, referred to as matrix and fracture, respectively. The matrix has high storage, but low flow capacity; the fracture has low storage, but high flow capacity. The flow in the entire reservoir is unsteady state. The results of this study are compared with the results of the earlier models, and it has been concluded that major conclusions of Warren and Root are quite substantial. Furthermore, an attempt has been made to study critically other analytical methods reported in the literature. In general, it may be concluded that the analysis of a naturally fractured reservoir from pressure transient data relies considerably on the degree and the type of heterogeneity of the system; the testing procedure and test facilities are sometimes as important. Nevertheless, under favorable conditions, one should be able to calculate in-situ characteristics of the matrix-fracture system, such as pore-volume ratio, over-all capacity of the formation, total storage capacity of the porous matrix, and some measure of matrix permeability. INTRODUCTION The analysis of flow and buildup tests for obtaining in-situ characteristics of oil and gas reservoirs has received considerable attention in the past decade. Most of the available techniques result in reliable conclusions in macroscopically homogeneous reservoirs or in the homogeneous reservoirs with only certain types of induced and/or inherent heterogeneity (such as wellbore damage, etc.). In general, the greater the degree of heterogeneity, the less the reliability of the information deduced from the pressure transient data. A commonly encountered heterogeneous system is a naturally fractured reservoir where two types of distinct porosities occur in the same formation. The region containing finer pores may have high storage and low flow capacities. This is called the matrix. The remaining region may have high flow capacity with low storage. The latter region is generally the set of interconnecting fractures and fissures of the rock, and for this reason it is called the fracture. Ordinarily, we wish to obtain the permeability and porosity of each region and perhaps the frequency of the fracture distribution in a reservoir. Such information is necessary for reservoir engineering. Other information, such as wellbore damage, will be useful in evaluating possible remedial work for such fields. Few authors have suggested theories to aid in calculating the in-situ characteristics of a naturally fractured reservoir similar to what we have described above. Pollardl suggested that a naturally fractured reservoir contained three distinct regions: a damaged or an improved region surrounding the wellbore, and the two remaining regions the same as described earlier. He suggested that the flow was taking place from the tight matrix into the highly conductive fractures, then into the we wllbore region and finally into the well column. He concluded that the average pressure buildup in each of these distinct regions can be expressed approximately in terms of an exponential decay function of time. He also hypothesized that the decay coefficients for each of these functions were significantly different from each other; consequently, each of these functions became dominant in turn, in the process of pressure buildup. Thus, by a proper graphic plot of the logarithm of wellbore pressure differences vs buildup time, each of these functions could be determined (see Fig. 1). Pollard suggested methods of determining the wellbore damage and fracture volume. Later Pirson and Pirson2 extended

Jan 1, 1970

By Arvid Anderson

THE weathering of copper-bearing ores with the formation of a water-soluble salt and the recovery of the metal by leaching and evaporation or precipitation, are processes long known, which have at various times been utilized with more or less commercial success. It is commonly assumed that the technical principles involved are quite simple and their application to a particular case easy. If these assumptions were true, we should anticipate a long list of uniformly successful leaching operations, which is not the case, and one would be justified only in calling attention to either unique or peculiar features of any particular enterprise; whereas, in studying the problems of the recovery of copper from the old workings of the Ohio Copper Co. in the light of available descriptions of other leaching projects, we have not found the assistance hoped for to guide us to the best realization of our own opportunities. It appears desirable, therefore, to call attention to these guiding principles, together with a description of the facts of accomplishment. Justification lies in the fact that the leaching and precipitation of copper at the Ohio Copper Co. mine in Bingham Canyon, Utah, is successful. This success is measured by an average monthly production of 600,000 lb. of copper at an average operating cost, to date, of 3.85 cents per pound at the company's workings, or 6.32 cents per pound after paying shipping and smelter charges on the finished copper. A total of 17,076,099 lb. of copper had been shipped to the smelter from the beginning of operations, August, 1922, to April 1, 1925. Probably these results can be bettered with further study and realization of the factors involved and the devising of methods of meeting them. It is now an assured fact that the enterprise will have a relatively long and continuously profitable life and that its reserves will not, nor cannot, be suddenly and permanently depleted.

Jan 9, 1925

By H. Shaw

Gravitational measurements made by means of the Eotvos torsion balance over any area enable a representation to be obtained of the total gravitational effects over the surface of that area arising from the combination of all sources of gravitational disturbance. The investigation of gravitational anomalies occurring in the upper layers of the earth's crust, in this way, has been attended with considerable success, and, especially in areas in which no undesirable disturbing factors were present, it has been possible to locate geological structures and mineral deposits with remarkable accuracy and also to delineate their confines and to indicate their depth below the surface with a certain amount of precision. Before this can be done successfully, however, it is necessary to determine the gravitational effect arising from all other extraneous anomalies in order that these may be satisfactorily eliminated. Disturbing features giving rise to these gravitational anomalies may be divided into two classes, according to whether they are situated at or below the surface. The former are determined readily by a detailed leveling of the ground surface, and may be satisfactorily eliminated provided the specific gravity of the terrain material is known, but the latter are generally unknown, and can only be ascertained with difficulty. When, therefore, the observations obtained by means of the Eotvos torsion balance have been corrected for all surface irregularities, known as terrain and topographical effects, there remain residual gravitational values which are due entirely to subterranean conditions. The. task of interpreting these results consists in disentangling the various subsurface anomalies, and subsequently in computing and recombining the effects of these various masses in order to verify the interpretation. When the gravitational anomalies are due to large and comparatively simple structures it is a matter of little difficulty to arrive at a satisfactory interpretation of the subterranean conditions, but in more complex areas, where the geological conditions are more complicated and several irregular features exist, the process of disentangling the various constituents of the complex mass arrangement is more difficult and requires the expenditure of considerable time and labor. When the subterranean effects have been obtained, they are subjected to a critical examination, and an effort is made to recognize and

Jan 1, 1932

By Charles Smeal, Robert J. Schafer, Max Quantinetz

Normally metal powders cannot be ground to sub-micron sizes because of welding and agglomeration phenomena. Through the use of selected grinding aids and grinding fluids, nickel and other metal powders have been ball-milled as fine as 0.1 It was found that certain inorganic salts are more effective grinding aids for metal powders than conventionally used surfactants. METAL and alloy powders are used to produce reagents, pigments, coatings, solders, brazes, and parts for industry by powder metallurgy techniques. They are also combined with refractory compounds to produce cermets and dispersion-hardened products. One of the interests at the Lewis Research Center has been to explore the potentialities of the dispersion strengthening process. Since the work of Ir-mann, many investigators have shown that the strength of dispersion-hardened products may increase with decreasing interparticle spacing.24 One approach to achieving small interparticle spacing is to combine fine refractory compounds and metal powders, preferably below 1 in size. In attempting to obtain fine metal powders, it was found that until very recently the best that could be obtained from commercial suppliers, particularly of ductile metals, was about 1.0 . Interest was therefore developed in providing finer metal powders for dispersion-hardening studies. Information obtained from the literature, from others working in the field, and from prior experimental work performed at NASA, led to a consideration of ball-milling as a technique to produce the desired materials. Some of the variables associated with ball-milling are the size, material, and nature of construction of the grinding container; the nature and amount of the grinding material and material to be ground; and the nature and amount of the grinding liquid and grinding aid, if employed, and the grinding time. In all ball-milling, welding and agglomeration can oc- cur as well as grinding. Because of the tendency of ductile metals to weld together, they are difficult to grind.5 The ultimate particle size obtained on grinding is generally the one at which the rate of grinding becomes equal to the rate of welding. To help delay welding and thus obtain smaller particle sizes, grinding aids are often employed. The principal objective of this investigation was to produce submicron metal powders by ball-milling the powders with selected grinding aids and grinding fluids. A secondary objective has been to attempt to explain the variations observed in grinding behavior by considering possible grinding mechanisms and correlating various parameters with grinding effectiveness. Three groups of ball-milling experiments were run; one in which the grinding aid was varied, a second in which the grinding fluid was varied, and a third in which the material being ground was varied MATERIALS, APPARATUS, AND PROCEDURE In the first group of experiments in which the grinding aid was varied Inco Carbonyl Grade B nickel powder initially 2.5 (all sizes refer to average particle size as measured by Fisher Sub -sieve Sizer) was used as the material being ground and 200-proof ethyl-alcohol as the grinding fluid. Surfactants, representative of typical organic structures, were selected as grinding aids. Inorganic salts used as grinding aids were chosen on the basis of the size and valence of their ions. Water soluble salts were used in order to facilitate their removal from the slurry after grinding. In the second set of experiments, grinding of the 2.5- Ni powder was tried in four different grinding liquids; water, cyclohexane, n -heptane, and methy-lene chloride. In this study seven grinding aids selected from those tried in the first group of experiments were employed. In the third group of experiments 200-proof ethyl alcohol was again used as the grinding fluid to mill Cu, Cr, Fe, Ag, and Ni powders of various initial particle sizes' All mill charges contained 300 ml of grinding liquid and 3000 g of 1/2 in. stainless steel balls. When inorganic salts were used as the grinding aid, 70 g of salt and 210 g of metal powder were employed, and with surfactants 6 g of grinding aid and 300 g of

Jan 1, 1962

By Russell W. Dayton

The metallurgical polarization microscope has been utilized in several researches in the last few years, thus attaining a fair degree of prominence, but little has been written in a manner suitable to a metallurgist concerning the theory of this instrument. In this investigation the theory was carefully studied, and the results are presented here in a detailed manner, yet as simply as possible. The theory is discussed with particular reference to the three chief functions of the instrument: (1) determination of anisotropy; (2) effect of strain; and (3) identification of inclusions. Each of these is investigated experimentally, with especial attention to the mechanism of producing any effect. Where possible, the discussion is supplemented by photomicrographs. The instrument used had numerous defects as a polarization microscope; these and their remedies are discussed. In the microscopic study of transparent mineral sections (chalcography) the use of polarized light has aided tremendously in the identification of a mineral. The determination of strain in transparent substances (photoelasticity) by the use of polarized light has lately become a commercial process, used in testing finished glass articles. The success of the use of polarized light with opaque materials has not been so great. The magnitude of the effects obtained is much less than that of the corresponding effects with transparent materials, and the mechanical difficulties are much greater. Königsberger,"' i in 1909, was the first to apply polarized light to the microscopic study of opaque substances; Endell and Hanemann(2) were the next, in 1913. In 1919 and 1920, Wright(3,4) prepared two papers on the subject. In the first he developed the detailed mathematical theory from the viewpoint of the electromagnetic theory of light, and in the second described the various methods in use, giving improvements of his own. Schwarz(5)

Jan 1, 1935

By Russell W. Dayton

The metallurgical polarization microscope has been utilized in several researches in the last few years, thus attaining a fair degree of prominence, but little has been written in a manner suitable to a metallurgist concerning the theory of this instrument. In this investigation the theory was carefully studied, and the results are presented here in a detailed manner, yet as simply as possible. The theory is discussed with particular reference to the three chief functions of the instrument: (1) determination of anisotropy; (2) effect of strain; and (3) identification of inclusions. Each of these is investigated experimentally, with especial attention to the mechanism of producing any effect. Where possible, the discussion is supplemented by photomicrographs. The instrument used had numerous defects as a polarization microscope; these and their remedies are discussed. In the microscopic study of transparent mineral sections (chalcography) the use of polarized light has aided tremendously in the identification of a mineral. The determination of strain in transparent substances (photoelasticity) by the use of polarized light has lately become a commercial process, used in testing finished glass articles. The success of the use of polarized light with opaque materials has not been so great. The magnitude of the effects obtained is much less than that of the corresponding effects with transparent materials, and the mechanical difficulties are much greater. Königsberger,"' i in 1909, was the first to apply polarized light to the microscopic study of opaque substances; Endell and Hanemann(2) were the next, in 1913. In 1919 and 1920, Wright(3,4) prepared two papers on the subject. In the first he developed the detailed mathematical theory from the viewpoint of the electromagnetic theory of light, and in the second described the various methods in use, giving improvements of his own. Schwarz(5)

Jan 1, 1935

By Haydn H. Murray

The term clay is somewhat ambiguous unless specifically defined because it is used both as a rock term and as a particle size term. Actually most persons using the term clay realize that it has a double meaning and in most instances define it. As a rock term, clay is difficult to define because of the wide variety of materials that compose it so that the definition has to be general. Clay is a natural, earthy, fine-grained material composed largely of a limited group of crystalline minerals known as the clay minerals. Many definitions state that a clay has the property of plasticity when wet, but some clays are not plastic, i.e., halloysite and flint clay; however, most clay materials are plastic when wet. As a particle size term, clay is used for the category that includes the smallest particles. The maximum size particles in the clay size grade are defined differently on some grade scales. Soil investigators and mineralogists generally use 2 microns as the maximum size. The Wentworth scale' defines clay as material finer than approximately 4 microns. Grim' has found it convenient to use the term clay material for any fine-grained, natural, earthy, argillaceous material and in this way can include clays, shales, or argillites, and some soils if they are argillaceous. Even though no standard definition of the term clay is accepted by geologists, agronomists, engineers, and others, still the term is generally understood by all who use it. Clay is an abundant natural raw material and has an amazing variety of uses and properties which will be discussed in this chapter. In order to understand better the relationships between the clays and their uses, a brief discussion of the structure, chemical composition, and identification of the clay minerals is given. Mineralogical Composition of Clays Clays are composed of certain groups of hydrous aluminum, magnesium, and iron silicates that may contain calcium, potassium, and other ions, which are called the clay minerals, and other minerals of variable composition, which are nonclay minerals. Both clay minerals and nonclay minerals influence the properties of a clay material. In order to understand the relationship between clay minerals and the properties of a clay material, a short summary of the structure and composition of clay minerals is necessary. Any scheme of classification tends to impose a certain rigidity and as new and additional data become available it is necessary to revise classifications. Brindley3 has discussed the classification and structural mineralogy of clays in very lucid fashion and chose a classification based on structural features and chemical composition. Grim2 proposed a tentative classification which is based on the structural attributes of the various clay minerals. This classification is relatively simple and workable, and is shown as follows: I. Amorphous Allophane group II. Crystalline A. Two-layer types (sheet structures composed of units of one layer of silica tetrahedrons and one layer of alumina octahedrons). 1. Equidimensional Kaolin group kaolinite, dickite, nacrite 2. Elongate Halloysite group

Jan 1, 1960

By D. H. Newland

During the year 1907 an investigation of the Clinton formation in New York has been carried out under the direction of the State Geologist, and a full account of the results has been prepared for publication.' The more important economic features of the report are summarized in the present paper. Previous knowledge of this, the type, section of the Clinton has been contributed mostly by Hall and Vanuxem in their reports for the Natural History Survey of New York, which were issued in their final form in 1842-43. Brief accounts of the ore-occurrences have been given by 13. T. Putnam? J. C. Smock: A. H. Chester: and E. C. Eckel.5 Prof. C. H. Smyth, Jr.,6 has discussed the origin of the Clinton ores in two papers, which, so far as the local occurrences are concerned, have removed all doubt that may have existed on that subject. Distribution of the Clinton Formation. The Clinton strata in New York State are restricted to a single belt, which extends from the eastern central part to the Niagara river, which it crosses, and thence continues for some distance into the province of Ontario. The New York

Jan 1, 1910

By Walter Renton Ingalls

Vague references to tin-deposits in Mexico are scattered throughout technical literature, and that country has been looked to as a likely source of a part of the world's supply of till at no very distant date; but thus far nothing but occasional small lots have come forward, so that the notion has arisen that these mines are either mythical or unworkable. So far as I am aware, there has not yet been published any description of the tin-deposits of Mexico except a few brief references; and this paper, based on a study of them made in 1892, is therefore offered.

Jan 1, 1896