Search Documents

[ ]

Jan 1, 1928

By H. R. Shidel

THIS paper summarizes the results obtained from the preliminary cementing of wells in an effort to cut off the bottom water. The object of this work was two-fold: (1) To prevent the oil sand from becoming flooded. (2) To plug off bottom water, thereby preserving the individual well and reclaiming production. Valuable suggestions and help have been given by the following named: Messrs. Kyle and La Velle, of the U. S. Bureau of Mines; Magnolia Petroleum Co.; Freed Oil and Gas Co. The cementing work was carried out under the personal supervision of L. J. Snyder. In an unpublished paper on the "Water Problem in the Augusta Field," S. K. Clark reaches the following conclusions: (1) That the great amount of water present is bottom water, occurring in the Varner sand, the main producing or the 2500-ft. horizon. (2) That the only striking connection between structure and water is in the area of the marked fault on the Ralston, E. C. Varner, and F. Varner leases in sections 8, 9, 16 and 17. (3) That the oil occurs in porous streaks, generally separated by fine-grained, well cemented sand, which is barren. Possibly two, or three such pay streaks may be found. That under a pay, fine-grained sand occurs, which is presumably barren at the time of drilling, but soon reveals water. The writer takes partial exception to the last point, because well defined shale, slate, lime, or hard sand breaks have been encountered in a great many cases, separating the pay streaks under which water is often found. This is not an invariable occurrence, as cases have been noted when the oil has been followed immediately by water in the same stratum. In an effort to overcome the water menace, the following methods of plugging were tried: (1) Plugging with wood, lead, and limit plugs. (2) Plugging with sand pumpings.

Jan 10, 1918

By H. E. N. Stone, B. L. Daniell

This paper examines the cracking behavior on chemical reduction of three types of ore/oxide briquette mixtures. The complex sintering/hardening atmosphere was replaced by 100% oxygen and the blast furnace atmosphere by a 5/95 hydrogedsteam mixture which was used isothermally at 700°C for a constant, arbitrary time. Cracking has been assessed by measurement of reduction expansion or increase in specimen diameter as a result of chemical reduction and a subjective index based on appearance and friability. Oxidized briquettes of iron ore concentrate crack on reduction'-3 in a manner which parallels the degradation of sinter in the Linder test. In the present work, the cracking behavior on chemical reduction of three types of ore/oxide briquette mixture has been studied. Firstly, LD converter fume with additions of silica; secondly, Oxfordshire ore with ferric oxide; thirdly, ferric oxide with separate additions of silica, alumina and lime. Motivation for the first-mentioned experiments lay in the improvement of the fume as furnace feed; for the second, in assessing the tolerance of a finely divided ferric oxide as a base for low melting point additions. The third series provided additional information. In this work, the complex sintering/hardening atmosphere is replaced by 100% oxygen and the blast furnace atmosphere is replaced by a 5/95 hydrogen/ steam mixture used isothermally at 700°C for a constant arbitrary time. The particular reduction conditions were known from previous experience3 to be capable of disclosing any tendency to cracking. Cracking has been assessed by measurement of reduction expansion (i.e., increases in specimen diameter as a result of chemical reduction) and a subjective index based on appearance and friability. Generally

Jan 1, 1970

By Alfred E. Hunt

The late Alexander Holley said, on returning from a careful study of the relative merits of the Bessemer and the open-hearth processes, as shown in the best European practice, that, in this country, the open-hearth process would live to attend the funeral of the Bessemer ; and he said this several years ago, when in this country the Bessemer plant and practice had been developed to far outstrip that abroad, and when, proportionately, it had reached an advancement much beyond the improvements in open-hearth plants and practice. At the same time, the prevailing idea in the metallurgical world, a few years ago, seemed to be in favor of the substitution of Bessemer for open-hearth steel for most of the higher qualities, and Bessemer enthusiasts loudly proclaimed, that as good steel for all purposes could be obtained by their favorite process as by the open-hearth. It was, in fact, confidently prophesied that very soon tool-steel and similar grades, which consumers had learned to specify, in ordering, to be made by the crucible process, would by common consent be made by the Bessemer, as best adapted to give the desired results. But these expectations have failed to materialize; not only do the crucible people keep on in the even tenor of their way and talk with pride of their comparatively large outputs of " hundreds " of tons per month, as usual, but the open-hearth people have kept fast hold of their original domain of nearly the entire amount of sheared plates, of locomotive tires, of large forgings, spring-steel, agricultural steel, steel castings and the like. Further, owing largely to one of the great advantages of the Bessemer process, which is also one of its inherent dangers, namely, its large output, it has also fallen into considerable disrepute for structural purposes. Not a few experienced engineers are now stipulating in their specifications that Bessemer steel will not be allowed to be used, especially for tension-members.

Jan 1, 1888

Jan 1, 1942

By A. W. Ambrose

The present plans for the Petroleum Division of the American Insti-tute of Mining and Metallurgical Engineers provide for two principal meetings in the year 1928. The first will be at Tulsa, Okla., in September or October, 1928, with the exact date largely dependent upon the date of the .International Petroleum Exposition. The officers wish to hold the meeting at the same time as the Exposition in order that members of the Petroleum Division of the A. I. M. E. may have the advantage of attending both meetings at the same time. It is planned that this meeting will be devoted largely to petroleum production engineering problems. A tentative outline of subjects to be discussed is as follows: 1. Repressuring New Oil Fields, and naturally in conjunction with this falls Repressuring of Old Fields. 2. Air or Gas Lift. 3. Flow Strings in New Wells. 4. Deep Drilling Technique. It is also planned to have at this meeting a general paper relating to Supply and Demand of Petroleum and its Products. The second meeting is planned for February, 1929, in New York at the same time as the annual meeting of the Institute. Special details have not been carried very far on this meeting, although it is expected the program will cover technical problems in relation to production and refining of crude oil, as well as 1928 development in foreign fields and the United States. It is planned during 1928 to cooperate with the Bureau of Mines in an attempt to compile a set of definitions on petroleum engineering. These would be of value to the petroleum engineering profession, in order to better standardize various terms used in discussion of current problems. It has also been suggested that the Petroleum Division study certain problems in which research work is needed by the petroleum industry and outline certain definite programs that could be carried out by the Bureau of Mines and the U. S. Geological Survey, as a follow-up to

Jan 1, 1928

Jan 1, 1934

By G. Sachs, E. J. Ripling, S. I. Liu, J. J. Lynch

It is a generally recognized fact that by repeated straining the fracture stress of any metal is reduced to a fraction of its value for static loading. The value of this fatigue strength depends upon numerous factors, such as the states of strain and stress, the limits of straining, and the number of repeated loadings or cycles The large volume of previous investigations on fatigue is concerned entirely with large numbers of cycles, say exceeding 10,000 and up to 500,000,000. However, the changes in fracture stress and fracture strain occurring after a small number of repeated loadings have attracted little attention. Apparently the only investigations of this type are those byLudwik4.5 who subjected steel, copper, and aluminum wire to repeated torsion. In each test the torque was varied between identical values in the two directions of twisting. Depending upon the magnitude of the moment, fracturing occurred after a number of cycles, up to 10,000. The results of Ludwik's tests will be discussed later Such torsion does not readily yield actual stress and strain values. Therefore a pre- liminary study was made of the effects of repeated direct stresses, that is, tension and compression stresses. Because such tests are considerably more tedious than torsion tests, only high stresses were used in the preliminary work, yielding definite changes in metal properties after a few cycles. It was found in these tests that strains could be controlled more readily than stresses in the investigated range of high stresses. This paper, consequently, deals with the effects of strains of equal magnitude but different signs. The metal was first prestrained in static tension by a certain amount then subjected to compression to yield the same amount of strain after unloading. This loading cycle was repeated up to a maximum of seven times. After various cycles, the stress-strain curves in tension were determined, up to fracturing. As material for these tests, the aluniinum alloy 24ST was selected because it exhibits a comparatively small amount of necking in the tension rest This alloy permitted, therefore rather accurate cont.rol at the high strains necessary to produce fatigue failures at less than seven cycles. The results of this invest~gation appear sufliciently interesting to extend the method of attack in various directions It is intended to study (11 the effects of cycles up to a tew thousands and (2) the effects of strains of different magnitude in tension and compression respectively 'The latter variable also includes a. a special case the effects of compressive strains.

Jan 1, 1949

By Norman J. Gibbs, John Sroka

INTRODUCTION At the point a company decides to begin mine development and wishes to convince lending institutions that the proposed operation will return their borrowed funds, plus interest, over the terms of the loan, communications between lender and borrower are crucial. The importance of the mine feasibility presentation should not be underplayed, especially as new projects continue to increase in size, complexity, and cost. While the content and emphasis of a report to the lender will vary according to the particular project and type of debt financing sought, there is a general base of information upon which all such studies are built. THE PROJECT'S TECHNICAL ASPECTS Here, the object is to satisfy the lender that he will not be unduly exposed to technical risks as a result of the physical scope of the project. Reserves The feasibility report submitted to financial institutions should include an adequate description of the geologic setting, mineralogy, ore types, and reserves broken down into such recognized categories as proven/probable/possible or measured/indicated/inferred. Rather than a bald statement of reserves, lenders prefer to have detailed information on: History of exploration Drilling, both percussion and core, with core recovery, drill hole spacing, analyses, and continuity of mineralization Bulk sampling, with core assay comparisons Overburden, with stripping ratios Specific methodology of reserve calculation, and Geologic reserves vs. mineable reserves. As a rule of thumb, a lender would prefer to see that reserves in the proven class alone are sufficient to support operations at the design rates until the borrowed funds are repaid. (See also Schreiber above in this Chapter.) Mining The rationale for adoption of a particular mining technique should be presented as well as descriptions and justifications for: Preproduction development Preliminary mine plan, with forecasts of grades and material movements Geotechnical test work which influenced decisions Mining recoveries and efficiencies Major equipment, with type, model, rating life, spares, replacement schedules, utilization, and productivity Manpower requirements and work schedules Design assumptions Ore stockpiling and blending Environmental requirements, and Waste disposal Processing If a new ore body is to be developed or a new process used, it is important to provide details of test work, scale up, and extrapolation factors. A basic process description with a summary of the studies which justify the intended processing route should be included with the following data:

Jan 1, 1985

THE metal iron has physical and chemical properties which are somewhat different from those of steels, but a knowledge of the pure metal is a useful starting point in studying the behavior of steels. Solid iron exists in two different crystalline forms, called alpha (a) and gamma (?) iron, the former being the ordinary form at room temperature. When heated above the "A2 point," 768 C (1414 F), the metal becomes nonmagnetic, and at the "A, point," 910 C (1670 F), it undergoes a change in crystalline form to become gamma iron. In the range 768 to 910 C, it is sometimes called beta (ß) iron to distinguish it from the magnetic alpha, but the two are identical in crystal structure. When gamma iron is further heated to 1400 C (2552 E), it changes into delta (d) iron, which is identical with beta or non- magnetic alpha iron. Pure iron melts (in an inert atmosphere) at 1537 C (2800 F); the melting point is generally lowered by alloys or impurities. PROPERTIES OF IRON AT HIGH TEMPERATURES Many of the properties of iron undergo abrupt changes at the transition temperatures.1 For example, in heating through the A, point, a sudden shrinkage in volume occurs. Similarly, melting is attended by sharp physical changes such as an increase in volume. Table 16-1 contains a summary of the measured physical properties of pure iron at several temperatures. Usually the properties change smoothly within the range of stability of a given form, but this is not always true. For example, the specific heat reaches a sharp maximum at the A2 point although no trans- formation occurs. (See Fig 14-1.) Solvent Powers of Liquid Iron. Liquid iron is capable of dissolving most of the other metals and many nonmetallic elements as well. Of the metals that are liquid at the melting point of iron, only lead, silver, and bismuth refuse to dissolve to an ap-

Jan 1, 1951

By A. Q. Tool

THE necessity of accurate temperature measurements in the glass-making industries is today being much more widely appreciated than in the past. The introduction of the modern simplified and perfected pyrometric methods in connection with exact regulation of furnace temperatures has caused a marked improvement in the glass product with a quickened rate of production. An example of the processes in which much improvement has been and still can be made is that of annealing or heat-treating the glass. This is one of the most delicate processes in glass manufacture and one that requires a most careful furnace control. The heat treatment is undertaken to decrease the possibility of breakage and, in glass for fine optical instruments, to prevent serious warping of accurately ground and polished surfaces and to make the glass more uniform throughout to the passage of light waves. These objects are accomplished by removing all the harmful stresses that exist in a piece of glass when it has been cooled too quickly or unevenly. Such stresses exist, for example, after it has been pressed, cast, or otherwise worked. Thus the process of annealing consists of heating the glass evenly to the temperature at which it softens just enough to relieve these stresses in a reasonable time and then cooling slowly and uniformly until the glass hardens again. Accordingly, the things that must be investigated and determined in order to anneal glass without loss of time are, the annealing temperature, the time that the glass should be held at this temperature while the stresses relax, and the quickest cooling procedure that will give satisfactory results. After these characteristics of the glass are known the problem is one of pyrometry and temperature control entirely. In cases when it is known that a glass article will be required to withstand some definite type of heat or mechanical shock it is often possible, by a proper heat treatment, to produce such a distribution of the stresses in the glass that it will be enabled to resist these shocks more effectively.

Jan 9, 1919

By H. Conrad, V. V. Damiano, G. J. London

The slip mode activated during the c axis compression of single crystals of commercial-purity ingot SR beryllium, high-purity (twelve-zone-pass) beryllium, and Be-4.4 wt pct Cu and Be-5.2 wt pct Ni alloys in the temperature range of 25° to 364°C was determined using two-surface slip trace analysis, slip-step height analysis, and electron transmission microscopy. All three techniques indicated the occurrence of copious pyramidal {1 122) (1123) slip in the alloys over the entire temperature range, the amount increasing with temperature. Pyramidal slip was also indicated in the high-purity beryllium by slip trace analysis and electron transmission microscopy, but the amount was somewhat less than in the alloys. For the commercial-purity ingot crystals, only a very small number of pyramidal slip lines were observed, and these were in the immediate vicinity of the fracture surface. No pyramidal dislocations could be detected by electron transmission microscopy in this material. Dislocatransmissiontions with Burgers vectors [0001] and +(ll20) were identified by electron transmission microscopy inthe (1122) slip bands, as well as those with the j (1123) vector. This was interpreted to indicate that the edge components of the 3(1123) vector dislocations activated during c axis compression dissociate upon unloading according to the reaction i (1123) — [0001] + 3(1120) THE microstrain c axis compression of single crystals of commercial-purity ingot SR beryllium (99.6 pct), high-purity twelve-zone-pass beryllium (99.98 pct), Be-5.24 pct Ni and Be-4.37 pct Cu alloys was described in a previous paper.1 This paper covers in detail the analysis of slip traces observed on two mutually perpendicular lateral surfaces of these specimens, and a detailed description of transmission electron microscopy studies performed on foils cut from the bulk crystals after they had been deformed to fracture in the c axis compression. Observation of slip traces on single surfaces of deformed single crystals are generally insufficient to positively identify slip or twinning modes. The use of two carefully cut and oriented perpendicular surfaces can greatly aid in the positive identification and index- ing of slip traces, although even this technique may be quite inadequate if more than one type of slip system operates and if an insufficient number of traces are observed on the surfaces. The problem is greatly simplified for symmetric cases like that for c axis compression of an hep crystal such as beryllium, in which the operating slip systems are all equally inclined to the direction of the applied stress, and each slip system of a given slip mode has an equal chance of operating. For such cases, the traces of any given slip mode observed on the surfaces cut parallel to the c axis are symmetrically tilted about the c axis. It is therefore possible to quickly determine whether one or more slip modes are operating. Confirmatory evidence in support of the observations made on the external surfaces can be obtained from foils cut from the deformed crystals and examined by transmission electron microscopy. This latter technique serves to identify not only the operating slip plane but also the Burgers vector of the dislocations which participate in the slip. For this purpose, a simplified technique based upon a double tetrahedron notation is used in the present paper. The planes and directions in the hep lattice are all designated by letters rather than indices and extinction conditions are easily determined if the Burgers vector lies in the plane contributing to the diffraction. RESULTS 1) Slip Trace Analysis. The standard (0001) stereo-graphic projection of beryllium is shown in Fig. 1. The two mutually perpendicular, lateral surfaces of the compression specimen are represented by the diametrical planes AA' and BB', also referred to as surface A and surface B. For the specific case represented (a Be-5.24 pct Ni specimen deformed by c axis compression at room temperature), the A surface is tilted 5 deg to the (10i0') plane and the B surface is tilted 5 deg to the (1120) plane. Two surface trace analyses may be facilitated by examining in turn the intersection of various great circle traces of specific pyramidal planes with two surfaces and comparing the angles made with the (0001) plane with those actually observed on the two surfaces. One then identifies the slip traces by trial and error on a best-fit basis. The (1122) type planes (it was found that slip occurred on these planes) are shown plotted on the stereographic projection in Fig. 1. One obtains directly the angles between the (0001) plane and the {1122) traces by measuring the angle from the periphery to the point of intersection along the lines

Jan 1, 1969

By James W. Burns

Thin, heavily doped n-type layers of GaSb have been grown on p-type GaSb substrates. Techniques have been developed for the growth of the n-type layers from a tellurium-doped gallium-rich solution. The solution used consists of 95 at. pct Ga and 5 at. pct Sb. The process consists of immersing the p-type wafer in the solution at a temperature slightly above the liquidus temperature, holding briefly to permit dissolution of the substrate surface, then decreasing the temperature to a value slightly below the liquidus to obtain 1 HE resistivity of n-type GaSb varies linearly with applied hydrostatic pressure, while the resistivity of p-type GaSb is insensitive to such pressure.1,2 The growth. Growth from a solution of GaSb in tin will also be described. In either case the substrate is clamped to a shelf at one end of a graphite boat, and immersion of the wafer and subsequent decanting of the solution is accomplished simply by tilting the furnace. The process is useful for the formation of p-n junctions in III-V compounds and has the advantage that the problems normally associated with diffusion of Group VI elements are not present. Layers up to 4.0 mils in thickness have been grown by the process. material therefore should be useful in a hydrostatic pressure-sensing device. A practical hydrostatic pressure sensor, however, requires the fabrication of GaSb sensing elements of several hundred ohms resistance. Attempts were made to prepare such elements by diffusion, taking advantage of the high sheet resistance of the thin diffused layers and depending upon the p-n junction to provide isolation from the base layer. Additionally, thin layers of conductivity type opposite from that of the base layer were pre-

Jan 1, 1969

By Fernando A. Buttazzoni, Jorge C. Munita

INTRODUCTION To provide a background for discussing long-range financial and operational planning in the mining industry, we would like to begin by describing the role of planning in Codelco. Having taken part in Codelco's planning process since its inception in 1976, we believe that useful conclusions may be drawn for the experience we shall relate. Although Codelco is a state-owned copper producer with an important role in the Chilean economy, and is consequently very much at the core of national economic planning, the following discussion is not related to government planning but to planning in an operationally and commercially autonomous business concern with all the characteristics of a private enterprise. The only way in which Codelco differs from private business is that its financial successes or failures have a more direct impact on the countryls ability to participate in international trade, to meet its international financial commitments and to achieve economic and social growth. Thus, what follows is a presentation of the conceptual features of the planning process at Codelco and a description of the current state of planning in the company. It is understood that certain conceptual components are basic to any formal strategic planning process, and that the components of Codelco's planning process are therefore generally applicable in similar companies. First, the mission and scope of operation of the company must be defined, and goals must be set to achieve leadership in the business activities in which it engages. Having set this framework, the company must constantly scrutinize those internal elements and conditions that are essential to fulfill its mission and achieve leadership. In Codelco this means considering the actions which can best serve to define future capacities, taking into account declining ore grades and determining optimal production levels; watching over the productivity and skills of its labor force, and; keeping abreast of technological developments in non-ferrous mining and processing. If the company is proficient in these three areas, it will be cost efficient and there- fore competitive. Codelco must also watch over the business environment in which it operates. The company sells concentrate, blister and fire-refined copper, wirebar, cathodes and wire rod and must study the behavior of the market to attune its product mix to the demand existing for these various commodities in the international market and the copper consuming industries in general. By examining the internal and external environment in which the company conducts its production and commercial operations, it is able to diagnose its strengths and weaknesses, to identify the hazards it must overcome to stay ahead in the copper trade, and to take full advantage of business opportunities as they arise. CHARACTERISTICS OF CODELCO-CHILE Although our subject is Codelco, readers should keep in mind that there are many other copper producing operations in Chile, all in the private sector, and many valuable deposits that may be exploited in the future. Codelco is the only public sector copper producer, although there is one other state enterprise that operates smelting and refining facilities principally to serve a large number of very small producers of copper concentrate. In the mid-19801s, Codelco is the largest copper mining company of the world and the largest producer and exporter of copper with yearly sales totalling close to US$ 1.8 billion in 1983. Moreover, it is a highly profitable copper company at a time when the world copper industry as a whole has reported losses for several years. Codelco-Chile is a fairly new organization. The history of the four mining operations it manages is much longer: El Teniente was opened in 1912, Chuquicamata in 1915, Salavador in 1959 -- with installations of the old Potrerillos mine dating from 1927 -- and Andina in 1970. Having had separate owners, the management systems of the

Jan 1, 1985

By P. D. Merica

Certain compositions of the light, i:e., aluminum-rich, alloys of aluminum with magnesium and copper have become quite well known within the past ten years under the name of duralumin. These alloys are used for rolling and forging and can be so treated as to develop quite remarkable mechanical properties. Thus a properly heat-treated alloy containing about 4 per cent. of copper and about 0.5 per cent. of magnesium, rolled into sheet or rod, will have a tensile strength of approximately 55,000 lb. per sq. in. (3866 kg. per sq. cm.) with an elongation in 2 in. (50.8 mm:) of about 15 per cent. This alloy, duralumin, was developed by Wilm,1 and its properties more fully described by Cohn.2 The authors considered it worth while to investigate the mechanical possibilities of the light alloys of two somewhat analogous ternary series; namely, of aluminum-magnesium-nickel and of aluminum-magnesium-manganese, to study the effect of variation of composition upon mechanical properties within the alumimum-rich group of the aluminum-magne-

Jan 7, 1919

By F. X. Tartaron

This paper deals with basic physical phenomena, which when combined and interpreted, lead to the same mathematical equations that describe comminution phenomena. Thus, a physical model is described that corresponds to the mathematical model presented in the writer's previous papers. '12 In the mathematical model, the energy consumed in breakage is related to the volume or weight of material broken and the size of particles broken. The equation E=2.303 Ck-a log x1/x2 was derived by multiplying the volume or weight of each size in an ideal Gates-Gaudin-Schumann size distribution by an energy factor. The product of these two factors gives the energy distribution among the different sizes in a single size distribution. The energy of breakage of a specific constant weight of one size distribution to another size distribution is given by the equation E = constant/kn-1. In this case, where the volume or weight is constant, the energy is proportional to the size factor 1/kn-1. In what follows, a physical theory will be presented showing that the energy consumed in comminution is proportional to the volume or weight of the material broken and to the reciprocal of the size of this material raised to a constant exponent. THE VOLUME FACTOR The atomic theory of matter reveals that in solids, atoms or ions are arranged so as to be in equilibrium at specific distances from one another. Although the atoms or ions are oscillating, there is a definite determinable mean distance between them and this distance is a balance between repulsive and attractive electrical forces. It therefore requires force to separate the atoms or ions and when an outside force is applied, it first produces strain in increasing the distance between the atoms or ions. This strain increases to the breakage limit on application of sufficient force. In brittle materials, there is negligible plasticity and when an elastic limit is exceeded, breakage takes place. The work done is the force applied per unit area times the cross sectional area of the ideal particle multiplied by the maximum strain per unit length at right angles to the area times the length of the particle. Thus the work done is proportional to the area times the length, which is equivalent to the volume of the ideal particle. If more than one feed particle is considered broken, each particle must be subjected to sufficient strain so that the breakage limit of its contained atoms or ions is reached in order for the particle to be broken. Thus, the energy of breakage is proportional to the total volume of the particles broken. If the particles are of different sizes, the size factor must be included to get a correct determination of energy of breakage. In the preceding, it has been assumed that there is a constant binding force between the atoms throughout the volume being strained. This, of course, is not true. It is known that there are many irregularities in the structure of matter and the binding force differs markedly in different portions. But the differences are only discernible by examining extremely small subdivisions of matter. In one order of magnitude of volume, cracks can be discerned separately from non-cracked neighboring material. In a smaller subdivision of volume, lattice dislocations can be isolated. When these situations are brought into focus, mechanisms of their behavior can be learned, leading to a fuller understanding of phenomena that occur in larger scale subdivisions of matter. Very often, however, the mechanisms that operate in small scale subdivisions have negligible effect in those of large scale, and there still is a place for deriving a mechanism for large scale conditions. The quantum theory is extremely valuable for use with photons and electrons, but is of negligible use with ordinary atoms and molecules. This paper deals with relatively large scale subdivisions of volume present in comminution phenomena. Hence, the effects of cracks, lattice dislocations, misplaced atoms, etc., are smoothed out in an average, constant for each relatively large subdivision of volume. This attitude is supported by experience. If two 10 cc samples of the same ore were ground identically, the same product would be obtained. However, if two samples, each a cubic micron, were conceived to be broken, then one sample might contain a crack and the other not, hence a different product would be obtained. Experience shows that ordinary samples used in comminution, behave as though no irregularity existed

Jan 1, 1964

By A. J. Strauss

The solubilily of lead in PbS as a funclion of lemperature has been investigated by means of Hall coej'icient (RH) measurentents OIL samples prepared by annealing and quenching Bridgman-grourz single crystals, which contain excess lead incorporated during /heir growth from the mell. For sufficiently long annealing times and sufficiently rapid quench rules, the samples obtained consist of n-lybe PbS snturated with In the semiconducting compounds PbS, PbSe, and PbTe, the point defects associated with the presence of lead in excess of the stoichio metric composition are shallow donors. The defects associated with the presence of excess nonmetal are shallow acceptors. lead at the annealing teuiperatiire, together luilh a dispersed second phase of lead microprecipitates. Due to the retrograde solubility of lead, the measured free carrier concentration (n = l/eR77) decreases with decreasing annealing tewperature (T) from- 2.4 X 10 em-3 for 1l85OK to 1.3 X 1018 cm-3 for 623°K. The dala are well-represented by the equation n =(1.08 x 102) exp[ - (0.37 ev.)/kT] cm-3 For most undoped samples of these compounds, the carrier concentration at room temperature and below is determined primarily by the stoichiometry, since the concentration of either excess lead or excess non-metal is large compared to the concentrations of intrinsic carriers and electrically active impurities. Therefore the dependence of composition in temperature and partial pressure can be investigated by means of Hall coefficient measurements, even though the deviations from stoichiometry do not exceed 0.03 at. Pct

Jan 1, 1968

By H. R. Shidel

This paper summarizes the results obtained from the preliminary cementing of wells in an effort to cut off the bottom water. The object of this work was two-fold: (1) To prevent the oil sand from becoming flooded. (2) To plug off bottom water, thereby preserving the individual well and reclaiming production. Valuable suggestions and help have been given by the following named: Messrs. Kyle and La Velle, of the U. 8. Bureau of Mines; Magnolia Petroleum -Co.; Freed Oil and Gas Co. The cementing work was carried out under the personal supervision of L. J. Snyder. In an unpublished paper on the "Water Problem in the Augusta Field," 5. K. Clark reaches the following conclusions: (1) That the great amount of water present is bottom water, occurring in the Varner sand, the main producing or the 2500-ft. horizon, (2) That the only striking connection between structure and water is in .the area of the marked fault on the Ralston, E. C. Varner, and F. Varner leases in sections 8, 9, 16 and 17. (3) That the oil occurs in porous streaks, generally separated by finegrained, well cemented sand, which is barren. Possibly two or three such pay streaks may be found. That under a pay, fine-grained sand occurs, which is presumably barren at the time of drilling, but soon reveals water. The writer takes partial exception to the last point, because well defined shale, slate, lime, or hard sand breaks have been encountered in a great many cases, separating the pay streaks under which water is often found. This is not an invariable occurrence, as cases have been noted when the oil has been followed immediately by water in the same stratum. In an effort to overcome the water menace, the following methods of plugging were tried: (1) Plugging with wood, lead, and limit plugs. (2) Plugging with sand pumpings.

Jan 1, 1920

By P. D. Merica, A. N. Finn, R. G. Waltenberg

CeRtain compositions of the light, i.e., aluminum-rich, alloys of aluminum with magnesium and copper have become quite well known within the past ten years under the name of duralumin. These alloys are used for rolling and forging and can be so treated as to develop quite remarkable mechanical properties. Thus a properly heat-treated alloy containing about 4 per cent. of copper and about 0.5 per cent. of magnesium, rolled into sheet or rod, will have a tensile strength of approximately 55,000 1b. per sq. in. (3866 kg. per sq. cm.) with an elongation in 2 in. (50.8 mm.) of about 15 per cent. This alloy, duralumin, was developed by Wilm,1 and its properties more fully described by Cohn.2, The authors considered it worth while to investigate the mechanical possibilities of the light alloys of two somewhat analogous ternary series; namely, of aluminum-magnesium-nickel and aluminum-magnesium-manganese, to study the effect of variation of composition upon mechanical properties within the alumimum-rich group of the aluminum-magne-

Jan 1, 1921

YEAR OF ELECTION 1913. FRANK DAWSON ADAMS, Montreal, Canada. 1933. KARL EIKERS New York, N. Y. 1922. FEDERICO GIOLITTI Torino, Italy. 1906. SIR ROBERT A. HADFIELD London, England. 1921. FRANK WILLIAM HARBORD London, England. 1917. HERBERT HOOVER Washington, D. C. 1941. DANIEL COWAN JACKLING San Francisco, Calif. 1939. HENRY KRUMB New York, N. Y. 1921. C. McDERMID London, England. 1913. EZEQUIEL ORDONEZ Mexico City, Mexico. 1935. ROBERT PEELE New York, N. Y. 1938. A.M. PORTEVIN Paris France 1937. JOHN V.W. REYNDERS, New York, N. Y. 1937. GEORGE S. RICE Washington, D. C. 1911. ROBERT H. RICHARDS Cambridge, Mass. 1934. T.A. RICKARD Victoria, B.C., Canada

Jan 1, 1941