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By H. W. Schreiber, H. R. Babitzke, R. E. Rodriquez, Patterson J. A., C. D. Masters, J. J. Schanz, R. B. McCammon, E. A. Noble, P. M. Krishna

A five-year effort by the ASTM subcommittee E10.14 on uranium resource evaluation has culminated in the approval of E901-82, Classification System for Uranium Resources (ASTM Standard E901-82, April 1983). The standard classification was prepared with participation of representatives from the US Department of Energy, the US Department of Interior's Geological Survey and Bureau Mines, utilities, and consultants. The classification a resource is based on level of knowledge and the economic producibility of the resource at a given time. Alphanumeric identifiers are used rather than words to avoid confusion with existing terms, definitions, and classifications. An example demonstrates the dynamic nature of the process of classification and attests to the necessity of addressing both the aggregate needs of broad-scale resource planning and the specific needs of individual property evaluation. Problems that remain infixing the classification a given uranium resource include uncertainty in estimating the quantity of undiscovered resources and resolving differences that may exist in deciding when the drill-hole spacing is adequate to determine the tonnage and grade of discovered resources.

Jan 1, 1985

By R. S. Shoemaker

Mines are closed for two reasons; exhaustion of ore or insufficient price for the mineral. On the other hand, the reopening of an old mine can be the result of any one of three events; the discovery of more ore, a sudden rise in the price of the product or the use of a new low-cost method of mining or milling the ore. Examples of the latter would be the open-pitting of an orebody previously mined underground as recently happened at Tyrone, N.M., or the adoption of acid leaching of an old pit as has been done at Miami, Ariz. The unique native copper mines of the Keweenaw Peninsula of upper Michigan have not been so fortunate. These deposits, which were first worked by prehistoric Indians, have been mined continuously from the early 1840's to 1968 when the last mines of Calumet and Hecla were closed and the Ahmeek mill. still using eight Nordberg steam stamps, was shut down. There are two types of deposits from which native copper is obtained; amygdaloid, which is a lava flow, and conglomerate, a sedimentary deposit of sand, rock fragments and pebbles cemented together. "In the amygdaloid, the copper is disseminated, or distributed much like the raisins in a cake; but in the rich Calumet conglomerate, the copper is more like a malleable rope or thread cementing the pebbles together." (C. Harry Benedict. Red Metal: The Calumet and Hecla Story, (Ann Arbor, Michigan, 1952), p. 42.) These deposits produced almost all of the copper used by the North in the Civil War and were substantial contributors to the copper needs of the United States in both World Wars. Some were mined to depths of as much as 9500 ft along the dip of the vein structure and 7500 ft vertically. Few of the mines ever really became worked out, but became uneconomical because of depth, pinching of veins or grades which dropped to about 1%.

Jan 5, 1972

By M. G. Corson

INFORMATION regarding the use of manganese alloys has hitherto been incomplete and available only from widely scattered sources. This paper attempts a systematic description of properties .and uses of alloys other than manganese bronze, manganin and duralumin, which are probably the only non-ferrous alloys associated with manganese in the minds of most metallurgists.1 PROPERTIES OF MANGANESE Manganese can react either acid or basic; it is hard to obtain in the pure state; it has two different crystalline lattice structures, both of the cubic system, one stable above 850° C. and the other below 650° C., both coexisting in the intermediate range. Although the commercial product is hard and brittle, the pure metal seems to be ductile. In fact Zhemchuzhny, in Russia, was able to obtain ductile manganese and draw it to fine wires by the simple expedient of adding about 3 per cent. copper to the alumino-thermic product. Copper most probably brings the silicides, aluminides, nitrides and carbides present in the commercial product into a much less harmful form of distribution. One industrial use that can be foreseen for wrought manganese articles is as anodes for electrolytic processes in sulfate and nitrate solutions, particularly with high voltages. A practically insoluble skin of manganese peroxide is likely to form in such cases and an insoluble and strong anode material will be available.

Jan 1, 1927

By L. F. Engle, M. A. Hewedi

SUMMARY Initial interest in using solutions of ammonium salts to leach native copper was documented in notes from an AIME meeting in 1871; By 1916-1917, application of the NH3-CO2-H2O system to recover nonferrous metals attained commercial significance, when it was used as a process for copper recovery by Kennecott Copper Corporation and Calumet & Hecla Mining Company. The Caron work in the early 1920s, Freeport Sulphur Company’s achievements leaching Cuban laterites during World War II, out- standing accomplishments in both eastern and western Canada, recovery of manganese related to the work of Dean -- all serve as landmarks as this One Century Review surveys a base for future technology. Current emphasis on compatibility of metals-producing systems with the need to meet environmental protection criteria provides special encouragement to researchers and engineers to find accept- able ways of recovering metals. The ever-present demand of management to design, build and operate facilities on a profitable basis provides additional impetus to apply information from the technical literature to that need. Examination of the general approach to this paper will reveal much that is firm and positive with respect to empirical results -- extractions, recoveries, amenability to familiar proven equipment and materials of construction common to the industry. Although there are many references, there are gaps in the basic scientific data that if filled could lead to even more usefulness; the paper attempts to indicate where further information is needed.

Jan 1, 1973

By Richard E. Chism

The metric system is now in official use in the Republic of Mexico, having been adopted by the Government in the year 1862. Athough it is used to compute all customs and other duties to be paid to the General Government, in the measurement of public and private lands arid in all freight and other transactions on the railroads, and is taught exclusively in the public schools, the system has made but slight head way among the people,and has not succeeded in displacing the old-time weights and measures, which are still used in ordinary commerce. The latter were founded on old Spanish models, but, owing to the inexactness of the first standards and to subsequent changes, differ at present very widely from their originals. As to local modifications, weights are the same all over the Republic, but measures of the same name differ greatly in capacity in different States, and even in neighboring towns. The value in the metric system here assigned to each denomination of the old weights and measures is that fixed by the Mexican Government at the time of the adoption of the metric system. The equivalents in American weights and measures were calculated by me from data found in Trautwine's Pocket-Book as to the comparison between the French and American weights and measures, and are believed to be correct. I shall be thankful for early notice of any error that may be detected, that it may be corrected before the final publication of this paper in the Transactions. Linear Measures. Kilometers. Miles. 1 legua (league) = 5000 varas . = 4.19 2.604375 Meters. Feet. 1 vara (yard) = 3 pies.....= 0.83800 2.749578 1 pie (foot) = 12 pulgadas.....=0.27933 0.916526 Inches. 1 pulgada (inch) = 12 lineas . = 0.02328 0.916526 1 linea (line).......= 0.00194 0.076577 The vara is also divided (for dry-goods-selling) into palms or cuartas (palms or quarters). Meters. Feet. Inches. 1 palmo or cuarta .. .. = 0.209500 =0.687394 = 8.248728

Jan 1, 1887

By Gerald V. Jergensen

Does an idea have merit? What does it cost to implement? Can the concept be implemented successfully? The ultimate proof is to try, then see. However, when there are many millions of dollars at stake, blindly building and trying requires considerable courage. Owners and investors in retrospect might choose other less complimentary words. So we might ask, "How might we establish the feasibility of an idea or concept before committing large sums of money to the ultimate test?" From this basic and prudent question, has evolved the engineering concept of the feasibility study. A feasibility study is simply a systematic evaluation of an idea or concept to determine the prospects for success. In a literal sense, a feasibility study considers an idea in terms of its data base, "builds" the idea on paper, "operates" that idea, calculates the cost and benefits, then measures the probable success in terms of some economic, technical or financial standard. Feasibility studies can be quite modest in scope yet provide useful insights as to the viability of an idea. A study might be initiated only to examine the completeness or validity of the metallurgical data base. Another study could be a search for a workable idea or solution to an already-identified possibly troublesome problem. In this latter case, the question, "Will it work?" may be far more important than, "How much will it cost?" Feasibility studies are sometimes global in scope, involving several dozens of specialists and examining an entire "grass roots" mining complex. Other studies may be less ambitious but equally important in examining an expansion proposal or developing new operating techniques. Studies may be commissioned to remove plant bottle-necks, solve maintenance problems and so on. The terms study and feasibility study are used interchangeably in this chapter. They denote a systematic method to examine a proposed concept or idea. DATA BASE Typically, studies are initiated with a minimum amount of specific information and a maximum number of assumptions. As the work proceeds and the data base expands, assumptions are replaced

Jan 1, 1982

Jan 1, 1932

By Charles Fettke

IN THE present day manufacture of glass nearly pure quartz sands are used almost exclusively as the source of the silica, which is the major constituent of all common varieties of glass. Ordinary soda-lime, such as bottle, common tableware, plate, and window glasses, contain from 65 to 75 per cent. of silica. OCCURRENCE Glass sands occur in nature either in the form of loose, unconsolidated sediments or in deposits in which the individual grains have been more or less thoroughly bound together by some cementing agent so as to form sandstones. While deposits of sand and sandstones occur both widely and abundantly distributed, deposits that are sufficiently free from other constituents than quartz grains, so that they can be employed in the manufacture of the better grades of glass, are, comparatively speaking, of rare occurrence. The major portion of the glass sand produced in the United States comes from sandstones. In order to be suitable for glass sand, they should be rather friable. The rock should break down readily along the cementing material between the grains and should not break across the grains rather than along the bond. Some of the sandstones used are so friable that only light shots of slow-burning dynamite are necessary to disintegrate them sufficiently for hydraulic mining, while others have to be passed through crushers in order to disintegrate the rock into its individual grains.

Jan 2, 1926

By Yinchang Wang

1. INTRODUCTION 1. Subject, and Scope The formation of the oxidized ores of zinc has been recognized as a subject of great importance in economic geology. For many years these ores have been much sought, partly because they are more desirable for metallurgical treatment and partly because they are apt to be freer from gangue than is the sulphide of zinc. Up to very recent years the oxidized ores were the principal source of the metal and at present they still furnish a large portion of the commercial production. . The oxidized ores of zinc include six minerals, as shown in the-following table

Jan 9, 1915

By M. R. Tek, K. H. Coats, D. L. Katz

The nature and the limits of validity of Darcy's law US applied to the flow of natural gas through reservoirs has been considered in order to resolve some controversial aspects of the effect of turbulence on pressure drops. The equivalence between various concepts and viewpoints advanced in the past by several investigators to explain how and why a gas well does not necessarily perform according to Darcy's law is shown. Starting with generalized equations of flow of fluids through porous media, a partial differential equation has been derived which accurately represents the flow at all rates. This equation has been numerically solved using an IBM 704 digital computer. The results permit plots of unsteady radial pressure distribution curves from which specific isochronal backpressure curves may be constructed. These back-pressure curves show the effect of the ,8 factor on the slope of the back-pressure curve. The calculations further indicate that the drainage radius for a gas well in turbulent flow propagates at a rate dependent upon the rate of production at the wellbore. This is quite different from the case with liquid flow or natural-gas flow in laminar regime. Additionally, the effect of reservoir inhomogeneities and crossflow between layers of different permeability on the back-pressure performance of gas wells has been conridered. In light of the current numerical results the significance and linlitation of the rate of flow function Y proposed by Smith" has been discussed. INTRODUCTION The relationship between the pressure drop and flow rate in problems of fluid flow through porous media is known to be affected by the nature of flow through the porous matrix. It has been observed by many that, for a range of flow rates, the pressure drop remains proportional to the rate of flow. When some flow rate is reached, however, it is usually observed that the pressure drop gradually begins to increase more than proportionally to the flow rate. It is well known that this phenomenon was first observed by Osborne Reynolds in 1901 in experimenting with flow through pipes. In his classical experiments, Reynolds made visual observations on the condition of streamlines evidenced by injecting a dye into water flowing through glass tubes. In these experiments, the abrupt transition between steady, "streamline, laminar" flow and unsteady random turbulent flow was found to be a function of the dimensionless group (Dvp/u), now known as the Reynolds number. During these experiments, in addition to observations on the nature of flow regimes, the proportionality between flow rate and pressure drop in laminar flow was contrasted with the nonlinearity between these variables in turbulent flow. Fancher and Lewis' reported data on various consolidated and unconsolidated sands in 1933. Their conclusions were that ". . . the flow of fluids through these porous materials closely resembles that through pipes; that there is a condition of flow in porous systems which resembles viscous flow, another which corresponds to turbulent; that the change from one type to the other takes place at a definite and reproducible condition for each system". In 1947, Brownell and Katz published a method to predict the laminar and turbulent flow behavior from the particle size, bed porosity and the particle sphericity, employing the friction factor-Reynolds number charts for pipes. Several investigators have verified the work of Fancher, Lewis and Barnes and presented their data as friction factor-vs-Reynolds number plots.' The equation which would represent the pressure gradient over the whole range of velocity must have an added term over that represented by Darcy's law. Accordingly, the pressure gradient necessary to sustain flow at the velocity (v) through a porous medium may be represented by the following equation, suggested by Forscheimer." The nature and the range of validity of Darcy's law has been the subject of studies by many investigators over the past years. While everyone seemed to agree on the need for a quadratic correction term to Darcy's law to make it effective over the range of velocities, the concept of inception of turbulence and the use of the term "turbulent flow" remained controversial. Some fluid dynamicists define turbulence as a flow

By J. Poijärvi, J. Rastas

Recently, when increasing attention has been paid to mercury for environmental reasons, the interest of several plants is directed to the removal of mercury from roaster and smelter gases. When Outokumpu Oy built its zinc plant at Kokkola in 1969, intensive development work was started to find an efficient and economic method for mercury removal from roaster gases. A process was developed, after laboratory research and pilot plant tests, to eliminate and completely recover mercury from the roaster gases. The process was commissioned in 1970. The behaviour of mercury in the roasting process and several possible methods of removing it from gases are discussed in this paper. Theoretical investigations and empirical tests show that the removal of elemental mercury from gases by sulphatization is very efficient. Further, it is stated how the technical process was built on this idea. The zinc sulphide concentrates contain small quantities of selenium, chlorine and fluorine. The role of selenium in the process is described. Similarly, the behaviour of chlorine and fluorine in the roasting, sulphatizing and scrubbing units has been discussed. Finally, the recovery of purified mercury and selenium from the precipitates is described.

Jan 1, 1973

By R. E. Collom

VARIOUS chapters already written in the history of development of the North Dome of Kettleman Hills are monotonously identical in the one underlying theme of conservation of oil and gas. Discovered on Oct. 4, 1928, by Milham Exploration Co. with its wildcat Elliot No. 1, the field has been subjected to practically every modern form of produc-tion restraint in the name of conservation. The record thus far developed shows that conservation was had for a time, at a price; and that unitiza-tion must he blessed by single ownership or 100 per cent participation to be effective. In fact, incomplete unitization places a heavy handicap upon its participants in the competitive development that follows.

Jan 1, 1937

By H. Kenyon Burch

INTRODUCTION THE Inspiration Consolidated Copper Co.'s plant at Miami, Ariz., was designed and built to make possible the profitable working of a low-grade, finely disseminated copper deposit containing 100,000,000 tons of ore averaging 1.64 per cent. in copper. From the-beginning it was evident that the-plant could not, be kept integral but that a break would have to be made somewhere in the flow-sheet, removing at least the concentrator to a site more suitable than any available near the mine. It was finally decided, after considering numerous arrangements, to do the coarse crushing at the mine, to store the crushed ore in a bin from which it could be loaded into railroad cars and to haul it to the concentrator, an excellent site for which was available about 1 ¾ miles from the mine. The original intention was to equip a plant to treat 7,500 tons of ore per clay, but through the acquisition and proving up of additional ore reserves, the introduction of the Ohio caving system, and the excellent results obtained in the test mill (which made it possible to treat a lower-grade ore than had been thought possible) it was evident that a plant of much greater capacity should be supplied. It was, therefore, decided to treat approximately 15,000 tons of ore per day, the duties of the four main divisions to be as follows:

Jan 9, 1916

By R. L. Slobod, B. H. Caudle, R. A. Erickson

In predicting the sweepout pattern efficiency to be expected in a .secondary recovery operation, the reservoir engineer is often confronted with a situation in which part of the producing formation lies between the last row of wells and the reservoir boundary. To date, there has been little or no reference in the literalure to sweepout pattern efficiencies in such areas. This paper presents the results, of a laboratory study in which the area contacted around the edge of a reservoir injected in a five-spot pattern was determined. The X-ray shadowgraph technique was used in this study. It was found that surprisingly large portions of the reservoir area lying outside the well network are conracted by the injected fluid before, abndonment conditions are reached. In fact, it can he said that at least 00 per cent of the circa lying outside the last row of wells and within a distance of one well spacing of these wells will ultimately be contacted by the injected fluid in the case of most water floods. Frorn the results given in this paper, it is possible to estitilate not only the extent to which encroachment into these areas will occur but also the injection volume necessary to produce the wells to abnndonment conditions. INTRODUCTION While considerable work has hern done in recent years1.?.'.''.' evaluating the fraction of the reservoir contacted as a function of the mobility ratio for several different well patterns, there has been practically no mention of what happens to the oil in that portion of the reservoir which lies between the last row of wells and the reservoir boundary. In fact, the assumption is generally made that little or no recovery can he expected From this area. This assumption is incorrect and in many cases will lead to seriouq errors in calculating reservoir performance. The fraction of the area outside the regular well pattern contacted in a five-spot injection system has been studied using the X-ray technique5 to follow the progress of actual floods in porous models of reservoir elemental areas. In this paper, the method for carrying out such a study and the results showing the fraction of the area in question swept as a function of mobility ratio and the produced fluids are presented. THE REPRESENTATION OF A RESERVOIR BY ITS ELEMENTAL AREAS She portion of the reservoir lying between the edge of a reservoir and a line connecting the outermost wells may be roughly designated as the part of the reservoir outside the regular well pattern. An example of such an area is shown as the shaded portion in Fig. 1. The case of a square reservoir utilizing a five-spot injection program and with one full well spacing between the outermost wells and the boundary (Fig. 1) was selected as the single example which would provide the most insight into

Jan 1, 1956

By George A. Morrison

THE Columbia Chemical Division of the Pittsburgh Plate Glass Co. is at Barberton, Ohio, 35 miles south of Cleveland. For many years large tonnages of limestone have been brought to the Barberton plant from distant points. The stone is here burnt in vertical kilns, the resultant product then hydrated and the hydrated lime used in chemical processing. To eliminate the expense of these shipments, the company decided to investigate a limestone bed known to exist on company property at Barberton, where the stone is used. The bed lay at a depth of more than 2000 ft. and was known locally as the "Deep Lime." Chemical analyses of sludge from churn-drill holes made some years ago proved that the limestone was of sufficient purity to warrant diamond-drill exploration. Four diamond-drill holes were put down at well-spaced intervals, to represent fairly an area of four miles by one mile. Cores logged as to chemical and physical conditions were found to compare closely, and to corroborate the earlier evidence that the limestone was of superior quality for chemical use. A plant of 300 tons per hour was subsequently decided upon. SITE The yard at the chemical plant was already so congested that location of the projected mine within its area could not be considered. Eventually a site was selected 2 miles northwest of the plant, near the main line of the Erie Railroad. Here 412 acres were owned outright by the company and stone rights were obtained on 250 additional acres. This location required a transportation line of nearly 2 miles (8800 ft.), crossing two major highways, and to avoid interruption of deliveries to the plant, overpasses were planned. GEOLOGY The limestone in the immediate vicinity lies about 2200 ft. below the surface. Geologists* identify this stone as Delaware of Devonian age. It is overlain by 18 ft. of unconsolidated (sand and gravel), 100 ft. of water-bearing sandstone, and finally 2080 ft. of shale into which sandstone in thin layers is interbedded. The contact of shale and limestone is abrupt, flat-lying and very pronounced. Berea sandstone, often found at 520 ft., is absent, but Euclid sandstone was encountered, together with a seepage of oil and a small amount of methane gas. The limestone bed itself is 345 ft. thick, and overlies 200 ft. of gypsum. The lower part becomes dolomitic as it approaches the gypsum. A detailed study of the drill cores indicates that the upper 50 ft, are highest in lime and reasonably low in silica. The physical make-up shows several separating cherty layers. These occur at definite horizons and cause distinct partings, which become horizontal planes of

Jan 1, 1943

By Luis Emylnn Salas

If the ordinary wet method be attempted for silver-bullion containing tin, much trouble is experienced, varying with the amount of tin present. Even with a percentage as low as 0.05, the end-point is masked by a persistent turbidity, while with amounts ranging from 0.5 per cent. upward, the determination of the exact end-point is impossible, owing to the finely divided or colloidal metastannic acid resisting all efforts to cause it to settle, or to give a clear supernatant liquid. The object of the following experiments was to seek a remedy for these difficulties, and to find the conditions whereby the Gay Lussac method might be applied directly to these bullions. Material containing tin is met with frequently in bullion from Mexico or Bolivia; and tin is carried (sometimes in large quantities) in jewelers' sweeps. 1. A bullion was prepared containing Ag, 74; Cu, 25; and Sn, 1 per cent. A weighed amount was treated by the humid assay-method as if it were an ordinary bullion free from tin. Ten cc. of HNO, (1.21) was added, and the bottle was heated until all traces of

Jan 1, 1913

By J. Gurland

The wmk is concerned with the estimate of the degee of continuity of a particulate phase dispersed in a matrix. The first section is a verieu: of the parameters nzeasurable by quantitative rnetallogvaphy, namely the contact area and, under certain conditions, the number of contacts between particles of one phase. In the second section, the frequency of particle contacts is related to the degee of continuity of a randomly embedded phase orz the basis of the lattice-percolation model of Hamrnersley and others. THE extent of continuity of the constituent phases may greatly influence the structure-sensitive properties of phase mixtures, particularly if the phase properties differ significantly. An example from the literature1 is shown in Fig. 1. The marked decrease of the electrical resistivity of sintered silver-alumina bodies near 25 pct by volume of silver presumably occurs because the more conductive phase changes from a discontinuous to a continuous structure. Other example of electrical- and thermal-conductivity transitions are cited by kingery In view of these observations, a knowledge and understanding of the connectivity of the microstructure may be of considerable practical importance. This study is concerned with one aspect of the genera1 problem, namely the estimate of the degree of continuity of a particulate phase dispersed in an opaque matrix. The first section reviews the parameters measurable on a polished cross section by auantitative metallography, such as the contact area and under certain conditions, the number of contacts between particles of one phase. In the second section, an attempt is made to relate the frequency of particle contacts to the degree of continuity of a randomly embedded phase. For the purpose of this discussion, the aggregate has two constituents: the particulate phase and the matrix. The latter is considered to be homogeneous. The term "particle" is used with the meaning of "grain", i.e., a minute unit of matter which is usually a single crystal of a readily distinguishable substance within the confines of a simply connected boundary. While many of the concepts which are used here to describe the structural variables characterizing the microstructure of phase mixtures are qualitative and ill-defined, they are presented with the intent of stimulating further work of a more general and rigorous nature. I) PARTICLE CONTACT, CONTIGUITY, AND MEAN FREE PATH 1) Measurement of Contiguity. The fraction of the total internal surface of a phase a shared with particles of that same phase in a two-phase mixture of and $ is indicated by the contiguity ratio:3 whereis the area of the interface between o particles, and Sap is the area of the interface between a particles and matrix P, per unit volume of mixture. The contiguity ratio ranges from 0 to 1 as the distribution of the a phase changes from a completely dispersed to a completely agglomerated structure. The interfacial areas may be obtained from simple intercept measurements on a random plane, after Smith and Guttman where and N are the numbers of intercepts between a random line of unit length on a plane of polish and the interparticle and interphase interfaces, respectively. The equations are valid for any distribution of particle sizes and shapes.

Jan 1, 1967

By E. R. Stover, J. Wulff

A tentative 870°C isothermal section, the solidus equilibria, and the solubility of Tic and graphite in the nickel solid solution have been determined with arc-cast specimens. Each of the Ni-Ti intermetallics forms two-phase fields with Tic; only Ti,Ni has a measurable solubility for carbon. A quasi-binary eutectic exists between Tic: and a titanium-rich nickel solid solution; ternary eutectics occur on either side, with TiNis or with graphite. Graphite is in equilibrium with a nickel solid solution containing a ratio of Ti/C which increases below the solidus. DURING the past decade, titanium-carbide cermets containing nickel or cobalt alloy binders have been widely studied for high-temperature and wear-resistant applications. Recent work has emphasized control of the carbide grain size and distribution2's and the thermal exparision match between the phases/ The present study was initiated to determine the phase compositions during the sintering or infiltration process, and during subsequent heating. Although the effects of additives and impurities in commercial compositions are important, it was necessary to consider first the pure ternary, Ni-Ti-C. Emphasis was placed on the nickel corner, since the nickel solid solution is the continuous phase in compositions having highest strength. Early metallographic work by Zarubin and Molkov- showed that solid solubility at either end of the section Ni-Tic is small. Edwards and Raine reported that nickel dissolves between 3 and 5 wt pct Tic at 1250° C, on the basis of microstructures of annealed, vacuum-melted powder mixtures. Although the solubility of nickel in Tic has not been measured, Tic formed by the menstruum process in liuid-iron solution contains as little as 0.06 wt pct Fe. BINARY SYSTEMS The most recent determinations of the three binary systems are summarized in Fig. 1. Titanium carbide (6) is predominant among the binary phases, and it melts above the boiling point of nickel. The Ni-C binary is based on separate liquid solubility' ) and solid solubilitylo measurements. The eutectic temperature, 1328OC, is taken from the solidus determination described below. However thermal analysis data by Morrogh and williams also show eutectic arrests in this vicinity in the absence of supercooling. The Ni-Ti binary is taken from the work of Poole

Jan 1, 1960

By W. C. Schroeder

PRACTICAL experience has shown that at elevated temperatures solu-tions containing sodium hydroxide may attack stressed steel in a manner that cannot be explained in terms of ordinary corrosion. Because the ductility of the metal has been greatly reduced during the reaction, the entire phenomenon is usually called "embrittlement." Thus, after several years of operation caustic evaporators have been so badly embrittled that rivets could be cracked off with the blow of a hammer. Since fine intergranular cracks are almost always present in the zone of fracture, it has often been assumed that a process of selective corrosion in grain boundaries was responsible for the failure, although this has not been clearly proved experimentally. Concentrations of sodium hydroxide below those necessary for the uniform, rapid attack of the steel surface are reported to be most effective in producing embrittlement2,3. In the operation of steam boilers a similar type of failure has been found, mainly in riveted seams or other capillary spaces where the solu-tion may concentrate and where high stresses may also exist. It is believed that in such localized areas the dissolved solids may reach a value many times the few hundred parts per million prevalent in the body of the boiler. While this type of boiler failure has been the subject of investigation for a period of 20 years', an understanding of its mecha-

Jan 1, 1936

By S. A. Hovanessian

Analytical solutions are obtained for calculating the pressure distribution in rectangular fields due to injection and/or producing wells located anywhere within the field. The field is assumed to be homogeneous with either constant pressure or no-flow boundaries. These solutions are extended to include the calculation of average reservoir pressure and permeability from pressure build-up curves. Numerical examples are given to illustrate the application of equations to practical problems. INTRODUCTION Pressure distribution analyses are of considerable importance in the field of reservoir mechanics. A number of papers dealing with this subject have appeared in the petroleum literature. perrinel in 1956 presented a summary of the methods available for pressure build-up calculations and discussed the applicability of each in some detail. More recently (1958), Hazebroek, et a1,2 discussed a theoretical method for obtaining pressure distribution in a radial field. Also in 1958, Nisle3 gave a theoretical solution of the pressure distribution in a field extending to infinity with a partially penetrating line source at the origin. Mathews, et a1,4 applied the method of images to existing solutions for pressure distribution in radial fields and obtained expressions for calculating pressures in bounded reservoirs. However, a literature survey revealed that a general analytical solution for the pressure distribution in a rectangular field, with injection and/or production wells located anywhere within the field, was not available. Such a solution could be used to approximate the pressure distribution in a field the shape of which is nearly rectangular. Furthermore, it could be applied to pressure calculations pertaining to a single well taken from a system of wells which were drilled in a rectangular pattern. In this case the boundaries of the well drainage area are considered to be the perpendicular bisectors of the lines joining the well and its nearest neighbors. The basic problem considered in this paper consists of a rectangular field with either constant-pressure 01 no-flow boundaries and with either an injection or production well located anywhere within the field. The physical properties of the rock and fluids present are considered to be constant. Analytical expressions are obtained for the pressure distribution within the field during the production or injection periods. These expressions, which are infinite series, can be used to evaluate pressure at any point within the field as a function of time and position. For fields containing more than one well (production and/or injection), the solutions for each well acting independently are superposed. That is, at any point in the field, the pressures due to each injection 01. production well acting alone can be algebraically added to give the pressure resulting from all wells acting simultaneously. Evaluation of the series solutions given in this paper is readily accomplished by means of an electronic digital computer; and, in most cases, sufficient accuracy is obtained by setting the upper limits of summation at 20. These solutions are extended to include the calculation of average reservoir pressure and permeability from build-up data. A number of numerical examples are given to illustrate application of the solutions to actual field problems. ANALYTICAL SOLUTIONS The partial differential equation representing the pressure distribution in a homogeneous rectangular field (see Fig. I.), having a single source or sink of strength (2, can be written*