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By Oliver Bowles

When a new type of equipment revolutionizes methods of quarrying one kind of stone, producers of other kinds focus their attention on its potentialities in their particular fields. The purpose of this paper is to discuss the accomplishments of the wire saw in slate, to show its more limited attainments in other kinds of stone, and to point out the possibilities of much wider application. A wire saw consists of a 3/16-in. or ji-in. three-strand wire cable that runs as a belt and cuts the rock by abrasion. (Fig. 1. The teeth of the saw are sand grains carried in the grooves between the strands. Accomplishments in Slate† Initial experiments with wire saws by the U. S. Bureau of Mines in the Colonial Slate Quarry, Wind Gap, Pa., in 1926, attained success so immediate and pronounced that within two years in virtually every quarry in the neighborhood of Wind Gap, Pen Argyl and Bangor, the most productive slate area in the United States, wire saws were substituted for channeling machines. An 80-ft. cut in slate is shown in Fig. 2. The technique of operation has been described in several reports (references at the end of the paper). The present purpose is to summarize the accomplishments in a large, typical slate quarry after nine. years of experience. Parsons Bros. Slate Co., at Pen Argyl, Pa., substituted two wire saws for six channeling machines in 1927. The following comparisons are made between the present method with wire saws and the former channel-ing-machine method. Rate of Sawing.—The average rate of cutting with a wire saw in the early days of its operation, as determined by the Bureau of Mines', wits 14 to 17 sq. ft. per hour. Parsons Bros. Slate Co. estimates the present rate of cutting at about 25 sq. ft. an hour, whereas the channeling-rnarhirle

Jan 1, 1938

By Rossiter W. Ph. D. Raymond

(From the President's Address at St. Louis, 1874.) IN the course of this address, President Raymond referred to the law, said to have been discovered at the French works of Terrenoire, that the amount of phosphorus may be increased without injury to steel, if the amount of carbon be proportionately decreased. The works named have been for more than a year, it is said, manufacturing in the open hearth, by the Martin process, steel rails containing as high as 0.35 per cent. of phosphorus, with about 0.15 per cent. of carbon, which were not found inferior to Bessemer rails. It is not claimed by the manager of the works that phosphorus is an ingredient to be preferred, or purposely introduced; but only that materials containing it (such as old iron rails, etc.), can be succesfully employed. Other parties have apparently a higher opinion still of the new manipulation, and are prepared to claim for "phosphorus steel" superior qualities. Mr. I. Lowthian Bell alluded to the subject in his recent address as President of the British Iron and Steel Institute, but without expressing a positive opinion. After pointing out that the commercial value of the process turned on the cheap manufacture of ferro-manganese, by means of which only could the necessary amount of manganese be introduced into the Martin bath, without increasing its contents of carbon, Mr. Raymond proceeded to say that the principle alleged to have been discovered at Terrenoire was already known years ago, in this country, at least. Not only had steel been manufactured here, containing high percentages of phosphorus, coupled with low percentages of carbon, and suitable for use in rails, boiler-plates, etc., but the reason of its surprising qualities had been distinctly surmised, if not widely proclaimed. The following analyses and extracts from private letters prove these assertions. Some of them assert a similar principle in -the case of wrought iron ; but the analyses, and the remarks based upon them, have reference solely to the steel manufactured under the superintendence of Mr. Slade, at the works of the New Jersey Steel and Iron Company in Trenton.

Jan 1, 1875

By Clarence Thom

This chapter presents, in summarized form, standard procedures for making separations of minerals from their ores by the froth flotation process to produce marketable concentrates. These are typical mineral separations which are being made commercially with the reagents and conditions generally used in the mining industry. Typical separations are presented for 17 metallic and 11 nonmetallic ores. The review of each includes a brief description of the mineral and the particular problem presented, general market specifications for its concentrates, an outline of treatment method, and kinds and quantities of reagents usually employed. This chapter does not include de- tails about ore preparation (crushing, grinding, and classification), elements of ore and pulp transportation (conveying and pumping), or concentrate preparation for market (thickening, filtering, and drying). In each presentation it is assumed, if not detailed further, that the ore is ground to the economical point of liberation of the minerals to be separated. Specific information, such as ratio of concentration and recovery, that depends upon the grade of ore being treated is considered beyond the scope of this chapter. Effective flotation separations that produce marketable concentrates may produce widely varying results in terms of percent recovery and still be economically profitable operations. Details of plant practice on specific ores are presented in Chapters 16 and 17. In this chapter the chemical names of the reagents are given. The extent to which different reagents are used in flotation plants in the U. S. is presented in Chapter 4. A compilation of the various flotation reagents, their trade names, manufacturers, and use has been prepared by H. T. Spedden. ANTIMONY The principal ore mineral of antimony, stibnite (Sb2 S3), is generally found in the U. S. in ore bodies in association with other valuable minerals such as galena (Pbs), sphalerite (ZnS), chalcopyrite (CuFeS2), or tetrahedrite (3Cu2 S – Sb2 S3), The sulfo-salt minerals of antimony, such as tetrahedrite or pyrargyrite, are often associated with high silver values, so that the presence of antimony may indicate economic importance even though the actual antimony content is low. Antimony is also significant to the mineral economy because of its occurrence in some ores where lead, gold, and silver are the

Jan 1, 1962

By J. H. Faulk

An examination is made of the various factors influencing drilling rate and drill bit life in various diameter holes. It is concluded that drill bits in the size range 4% to 6 1/4 in. can be used to attain substantially the some daily drilling progress as conventional size bits in soft rock drilling operations. An examination of the most important factors influencing "hazard of losing the hole" in the different hole size results in the conclusion that the smaller hole sizes can probably be drilled at reasonably low risk. However, this risk will be somewhat greater in the smaller diameter holes, requiring that special drilling and mud engineering practices be used to make small diameter holes practicable in soft rock drilling operations. An engineering analysia is made of the power and hydraulic requirements of several drill string-hole combinations to test the feasibility of drilling .small diameter holes in soft rock areas. Large econormies in rig power requirements appear possible by drilling .smaller .size holes in these operations. INTRODUCTION The industry now is re-examining the utility of small diameter holes in the light of substantial technical advances made in recent years. Faced with increasing cost of finding reserves and with proration after developing them, the industry must either develop methods of economizing or receive a lower rate of return on investments. Small diameter holes appear to involve an attractive method of economizing. Our objective is to determine if this is technically possible in soft rock operations. Soft rock, as used in this report, refers to those formations of a "drill-ability" corresponding to that of all Gulf Coast formations shallower than and frequently including much of the Eocene rock system. An important phase of technology which we shall examine is relative drilling rate and bit footage which may be obtained with various size bits. Rig operating efficiency, particularly as influenced by hazard, is also discussed in detail. The technical conclusions resulting from these examinations are used to develop sample drill string design and rig horsepower requirements for drilling holes as smaH as 4 3/4 in. and larger. The principal criterion used for the drill string design is that approximately the same daily drilling progress would be possible in all size holes in soft rock operations. This facilitates a comparison of rig size required for drilling the hole sizes in the range between 4 3/4 and 8 3/4 in. BROAD PROBLEM OF DRILLING RATE AND BIT FOOTAGE The three factors controlling daily drilling progress are: (1) drilling rate of bit while on bottom turning, (2) bit footage, and (3) rig operating efficiency. Let us look now at the first two of these factors. Drilling technology has progressed to the point that a semi-quantitative analysis of the effect of various operating variables upon these factors can be made. Those factors which apparently limit both drilling rate and bit footage for bits now in use are: (1) bit design, (2) weight on bit, (3) hydraulic cleaning capacity for bit cutting surfaces and hole bottom, and (4) rotary speed. (We neglect the effect of mud and formation properties because these factors arc the same for the various size bits.

Jan 1, 1957

By Don B. Shupe, John K. Berry

The handling and disposal of mine water is a much larger problem than is apparent at first glance. Many more tons of water are removed from underground coal mines in the United States each year than tons of coal. In the old anthracite region of Pennsylvania the average was around 32.7 t (36 st) of water for each ton of coal produced, while bituminous mines average about 4.5 or 5.4 t (5 or 6 st). Water encountered in the mines may come from several different sources. In mines with light cover and without a firm solid roof, rain may seep directly into the workings. This is also true of deeper mines where pillar falls have broken the roof to the surface. The top under creek beds is generally faulty and broken and water comes through the roof at this point. Deeper mines are frequently overlain by water-bearing strata and pillar breaks and faulty top can admit water, while places running to the dip often accumulate water which comes up through the bottom. In all cases, except where passing under a year-round stream, the amount of water made is usually pretty closely connected with the weather-more water during the rainy season, less in the dry, although the deeper a nine is, the longer it is before changes in rainfall are felt. Another source of water, not connected with seasonal changes, is old water, accumulated over a period of time in abandoned workings of the mine, or from flooded adjacent mines. Here the water filters through the coal, the parting, or comes up through cracks in the bottom. Similarly, core holes, drilled to prospect the property, can be a source of unexpected water and modern safety requirements for dust-allaying water at the working faces can turn a pleasant working area into a soggy mess over the weekend if the system is not properly maintained and operated. Why water must be disposed of is obvious. If allowed to accumulate, sooner or later the mine will fill up, or at least it will become "roofed" in low places, blocking ventilation and traffic. It must be controlled long before it reaches this stage. Water standing in the working faces is

Jan 1, 1981

By L. J. Buteau, R. E. Reed-Hill, W. A. Slippy

In a zirconium {1121} twins tend to have coherelzt boundaries and thus do not usually taper to a point when they intersect a grain boundary. Under the proper conditions, a (1121) twin may deform a boundary in such a manner as to clearly rcveal the twinning shear. Measurements of these grain-bounrlary rotatzons yield a value of 0.63 for the (1151) twinning shear. The magnitude of the observed shear and its shear sense are in excellent agreement with the assumption that the second undis-torted plme (K2) for this form of twinning is the basal plane (0002). The present value of the tzvinninz shear, which is approximately three limes larger than Rapperport&apos;s value? is in excellent agreement with reported results of Sokuskii and Prolsenko.5 RECENTLY westlake&apos; reported a study of the twinning modes of zirconium based on ~ap~er~ort&apos;s2 values for the twinning elements. He observed that two of the modes, (1012) and {1122), can be explained by relatively simple dislocation models. A workable model for (1121) twinning, however, proved to be very complex and questionable. Because Rapperport&apos;s second undistorted plane, (K2), for (1121) twinning has large indices, {ll2l6), it is possible that the difficulty in defining a model for (1121) twinning lies in an incorrect value for K2. A measurement of this twinning element has therefore been made, using a method based on observations of the shear displacement of grain boundaries at positions where they are intersected by (1121) twins. EXPERIMENTAL PROCEDURES The zirconium specimens were deformed in tension on an Instron machine either at the temperature of liquid nitrogen (77ºK), or prestrained at liquid nitrogen temperature and then further deformed at room temperature. Straining at 77°K was employed in order to nucleate (1 121) twins in large numbers, since simple ropm-temperature tensile deformation favors (1012) twinning. Specimens were machined from 1/2-in.-thick plate. The material was arc-melted sponge zirconium annealed to an ASTM grain size 4 and containing, in parts per million, 380 Fe, 880 0, <40 Hf, 32 N, and < 5 H. The specimen gage length and diameter were 1.25 and 0.130 in., respectively. To insure a gage section initially free of twins, the last 60 thousandths of the specimen diameter was removed by acid machining.

Jan 1, 1963

By A. U. Seybolt

As is well known, many questions affecting the properties and uses of a metal cannot be answered without careful consideration of the state of purity realized in the various operations of preparation, refining, or special treatment that have brought the product to its final state. The occurrence of an impurity in minute quantity offers no guarantee that its effect will be inconsiderable because dissolved substances often modify the properties of a metal quite out of proportion to their concentration. In such cases the determination of solid solubility must be accepted as a problem of considerable difficulty, requiring the use of especially purified materials and methods not ordinarily used in the metallurgical laboratory. This aspect of the equilibrium between metals and their oxides is especially important and a search for fundamental data reveals little except .conflicting opinion even concerning the systems of common occurrence and interest. Rhines and Mathewson1 in 1934 studied the solubility of oxygen in solid copper by annealing to equilibrium in air and gave reasons for the failure of other methods, notably the ordinary procedure of heat-treatment followed by microscopic examination, to yield reliable results. In this paper, a similar study has been made of the solubility of oxygen in cobalt. The simple theory of this method is outlined below.

Jan 1, 1935

By C. M. Loeb, T. E. Norman

The use of ball, rod and tube mills for grinding ore, cement and other materials has grown so rapidly during the past forty years that the world&apos;s annual consumption of ferrous grinding media for these mills is now estimated to be between one half million and one million tons per year. Ferrous grinding balls constitute the major portion of this tonnage. Obviously they represent sufficient value to justify thorough studies of the factors governing their performance. The selection of grinding balls is governed principally by: I. Quality (wear resistance, impact resistance, soundness, and the like). 2. Sources of supply and delivered cost. 3. Grinding characteristics or efficiency in the ball mill. This paper deals principally with the quality of ferrous grinding balls. In the study of these factors certain data relative to the fundamental nature of ball wear in ball mills have been obtained. These data are also presented and discussed briefly. The Development of a Suitable Wear Test A study of the fundamental factors governing the quality of grinding balls has been hampered seriously by the fact that a competent test has, in the past, involved the purchase of several hundred tons of balls of a specific type which were then run in one or more ball mills for a period ranging from several months&apos; to several years&apos; duration. Often, during the period of test, it became necessary to change operating conditions or the character of the ore fed to the test mill with the result that the rate of ball consumption changed and the test figures became of little value. Under such circumstances, progress in the development of better grinding balls, has been necessarily slow. Economic factors and variations in the quality of balls produced by different sources of supply generally make it necessary for each mill operator to determine for himself the most suitable type of balls for his mills. In our own ball mill grinding operations at Climax, Colo., we were faced with this problem. After we had run a few large scale wear tests at considerable expense we decided to investigate the possibilities of a small scale wear test which would be capable of testing numerous types of balls within a relatively short time. The most important requirement of any test is, of course, that it give results which can be used to predict accurately the wear in full scale operations. It was known that Ellis and his associates1,2 had developed a method of testing grinding balls by small scale tests run at the Ontario Research Foundation. Ellis&apos; method of testing was used as a starting point in our investigations. In the course of our tests a number of modifications of the original method were found to be desirable so that, by an evolutionary procedure, a method of small scale

Jan 1, 1949

By Donald D. Carr, Lawrence F. Rooney

Perhaps no other mineral commodity in this volume has as many uses as limestone and dolomite. These carbonate rocks are the basic building blocks of the construction industry, the material from which aggregate, cement, lime, and building stone are made. Carbonate rocks, and their derived products, are used as fluxes, glass raw material, refractories, fillers, abrasives, soil conditioners, ingredients in a host of chemical processes, and much more. Although the use of limestone and dolomite goes back before recorded history, new uses and products are continually being found. Carbonate rocks form about 15% of the earth&apos;s sedimentary crust and are widely available for exploitation. Found extensively on all continents, they are quarried and mined from formations that range in age from Precambrian to Recent. Reserves of carbonate rock are large and will last indefinitely, although high-purity deposits may be absent or have limited availability in certain areas. Limestone and dolomite are so useful and so abundant that in 1981 about 644 million tons were produced in the United States. In fact, about 75% of all stone quarried or mined in the United States was carbonate rock. Sand and gravel was the only mineral commodity produced in greater quantity. In this chapter we have sought to provide the general reader an overview of carbonate rocks, their composition, distribution, production, and uses, with emphasis on developments since 1960. In doing so we borrowed extensively from our report on the applied geology of limestone and dolomite (Rooney and Carr, 1971). The literature on the limestone and dolomite resources of the United States and Canada is so vast and diverse that one can easily become mired down in print. We tried to list those references that are easily accessible and that provide the economic geologist with a starting point for more intensive study. The table listing selected references on limestone and dolomite resources in Canada and the United States reflects our attempt to be selective rather than exhaustive and to direct the reader to the best sources of detailed information. Geology Mineralogy The principal carbonate rocks used by industry are limestone and dolomite. Limestones are sedimentary rocks composed mostly of the mineral calcite (CaCO3) and dolomites are sedimentary rocks composed mostly of the mineral dolomite (CaCO3 • MgCO3). Aragonite (CaCO3), which has the same chemical composition as calcite but a different crystal structure, is economically important only in modern deposits, such as oyster shells and oolites. Aragonite is metastable and alters to calcite in time. Some other carbonate minerals, notably siderite (FeCO3), ankerite (Ca2MgFe (CO3)4), and magnesite (MgCO3), are commonly found associated with limestones and dolomites but generally in minor amounts. Because of their similar physical properties, the carbonate minerals are not easily distinguished one from the other. Specific gravity,

Jan 1, 1983

By G. E. Steudel

THE study of the possibility of effecting a lower cost in the manu-facture of pig iron reveals the importance of the ever present question of slag chemistry and volume. Factors that determine slag chemistry and volume are the impurities in the ore available, the ash-sulphur content of the coke, and a flux material necessary to promote removal of sulphur. Of these, the ores present by far the major source of impurities and what may prove to be the lowest practical slag volume with desired chemistry in one locality may be considered low or high in some other center of iron manufacture. The Chicago district is not only blessed with ores of high quality, but with excellent coke and flux materials as well. It is the intent of this paper to discuss slag problems at the South Works only, where burdens consist of Mesabi ores, Michigan stone, and coke ranging from 7 to 9 per cent ash and containing an average of 0.57 per cent sulphur. Early in the development of modern blast-furnace practice, the con-sideration of slags was secondary to the many adjustments of mechanical difficulties, such as furnace lines, stock distribution, stove design for obtaining higher blast temperatures, improved chemical segregation and size of raw materials. Furnace operators, after making these improve-ments, turned their attention to the study of other refinements in practice, of which slag chemistry appeared to be the most important. It is only within the last two decades that operators have become familiar with the various aspects of slag compositions. The industry, while rather slow in its recognition, is indebted to such investigators as Rankin,1 Wright,1 Feild,2 Royster,2 McCaffery,3 Kinney,4 Holbrook,5 and Joseph5, whose researches concerning the elimination of sulphur within the blast furnace and the effect of slag composition upon melting point, viscosity, and desulphurizing power have established criteria for the selection of slags of the requisite quality.

Jan 1, 1939

By J. A. Stachura

Continuous mining machinery provides the coal industry with one way to compete for a larger share of the total energy market. Various types of machines are discussed and some of the problems with continuous miners, encountered by operators, are reviewed. Equipment manufacturers are working with mine personnel to provide solutions for problems that arise. While coal production over the past 25 or 30 years has been on a horizontal plane, coal&apos;s share of the total energy market has declined. To participate more effectively in this total energy market, it is necessary to produce coal more efficiently. It is the obligation of all management, employes, and mining departments to gear the deep mining industry to the rapid progress and changing of today&apos;s modern industry. This can be accomplished in the near future with the selection of the proper type of continuous miner best suited to each operator&apos;s individual situation. In most mining operations there is tremendous incentive to undertake the continuous mining program. It can reduce the size of the mine greatly by permitting a minimum of working places; it makes pillar recovery work more efficient from the standpoint of overall cost, amount of coal recovered, and safety. The work force can be reduced materially permitting closer and more efficient supervision. It simplifies maintenance because equipment can be more readily standardized. The trend of the coal market favors the use of continuous mining machines. Although there appears to be a general feeling that continuous mining is still a relatively new program and will be slow in replacing conventional mechanical equipment, the fact is that tremendous strides have been made since the first machines were installed in 1948. This program is advancing at approximately the same rate that mobile loading machines replaced hand loading. From 1948 to 1955 there were approximately 450 continuous mining machines in service. In October 1959, a survey revealed that there were more than 700 continuous mining machines in service. Many operators have expressed a desire to undertake this program, but they feel that they could not do so at this time because of one or more of the following reasons: 1) the thickness of their coal seams, 2) seam characteristics, 3) soft bottoms, 4) bad roof conditions, 5) size consist, 6) insufficient flexibility in machines, 7) difficult ventilation problems, and 8) high maintenance costs. With the realization on coal about the same today as it was in 1948, or slightly less and since coal is still failing to participate to a greater degree in the total energy market, it is not surprising that the coal industry is desperately exploring more economical methods for deep mining. The manufacturers are aware that the coal industry is willing to invest in continuous miners if the equipment is built for maximum flexibility, will produce higher tons per man, and assure long life between overhaul programs. CONTINUOUS MINING MACHINES Before discussing details regarding the selection of a continuous miner, let us have a preview of some of the continuous mining machines which are available to the coal industry today. Jeffrey Manufacturing Co.: The machine shown is the Jeffrey 76 A.M. Colmol. This is their most widely used miner, and has been particularly successful in central Pennsylvania and in high-wall mining in western Kentucky. One of the outstanding features of this auger-type miner is its portability. The entire mining range can be changed from its lowest point to the maximum height without stopping the mining operation. Jeffrey 76 B.M. Colmol: This machine is similar to the 76 A.M. model; however, it is built bigger and stronger for a mining range of 50 1/2 to 72 in. This is the model that is now available (Fig. 2). Jeffrey has added two arms to the top row, omitted the odd arm in the bottom row, thus permitting a 50 pct larger throat opening. This eliminates one

Jan 1, 1961

By J. E. Hilliard

It is proposed that shape anisotropy in the internal structure of materials be defined by distribution functions which specify what fraction of the total line length or boundary area lies in a given direction. Methods are descriibed for determinirg these distribution functions from measurements on sections through an opaque material. New derivations, that have certain advanifages over those given previously, are Provided for well-known expressions used in estinzating the total density of lineal or areal features. INCREASING attention is being given to the quantitative description of imicrostructures in metals and other materials. This interest stems from the recognition that the structure often provides a convenient half-way point between the properties on the one hand and the processing variables on the other. Such cross correlations become increasingly desirable as materials become more complex and the demands on them more stringent. One of the principal aims in structure analysis is therefore to find parameters that are readily measurable and specific enough to be correlated with other properties of the material. Certain properties, such as magnetic and mechani cal behavior, are strongly influenced by structural anisotropies; in order to relate such properties to the structure it is obviously necessary to have means of specifying and measuring the type and degree of anisotropy. For the determination of preferred orientations in crystal structure, X-ray diffraction methods are available and are widely used, but scant attention has been given to the estimation of anisotropy in the shape of grains and particles. It is the latter problem that will be considered in this paper. It is evident that shape anisotropy can be describe in terms of preferred orientations of lineal and area elements of the structure. It will be shown that these preferred orientations can, in turn, be specified by distribution functions that define what fraction of the total line length or boundary area lies in a given direction. Methods will be given for determining the distribution functions from measurements on sections through the structure. Even when the orientation distributions are of no interest per se, they still have an important bearing on the measurement of the total line length or boundary area by means of an intercept analysis. The treatment in terms of orientation distribution functions leads to new derivations, that have certain advantages of those given previously, for the well-known expressions used in estimating the total density of lineal or areal features. The treatment is divided into two main sections. The first deals with the orientation distribution of a two-dimensional array of lineal features such as occurs in the projected image of dislocations in electron transmission microscopy. The other section treats the estimation of the distribution of lineal and areal features dispersed in three dimensions.

Jan 1, 1962

By B. L. Landrum, P. B. Crawford

Theoretical and potentiometric model studies have been made of the effect of non-uniform lateral permeabilities on pattern sweep efficiency and production capacity in waterflood and gas-cycling programs. It is shown that a diflerence in directional permeability by a factor of three may result in a sweep efficiency of only 43 per cent for a five-spot pattern or a sweep of either 79 or 38 per cent for a direct line-drive square pattern, depending on the direction of the line-drive flood. Changes in the pattern conductivity varied from about 0.8 to 1.34 over this same permeability variation, depending on the pattern used. It is suggested that measurements be made to determine the possible magnitude and extent of the directional permeability phenomenon early in the field developinent and certainly prior to the initiation of any fluid-injection progmm. INTRODUCTION Irregularities in reservoir sand properties long have been a major difficulty to anyone attempting to explicitly describe the field characteristics of oil production. In particular, it is well known that vertical and lateral permeabilities often differ appreciably; however, the existence of large regions with lateral permeabflity variation is not widely recognized. A number of years ago, extensive studies were conducted by the Secondary Recovery Research Labcratory of the Pennsylvania Grade Crude Oil Association, primarily on the Bradford field. Johnson and Hughes&apos; reported a permeability trend in the northeast-southwest direction. They indicated that flow in the preferred direction may be 25 to 30 per cent greater in that direction than in the northwest-southeast direction. They also reported that similar effects may be found in other nearby fields. The origin of the permeability variation has been discussed by Griffith Hutchinson&apos; described the results of labora- tory tests on limestone cores, pointing out that per-ferential directional permeabilities were significant in one-half of 10 formations studied and that the average permeability ratio was 16:1. Barfield, Jordan and Moore analyzed the fluid-injection displacement performance in the Spraberry and reported that the effective ratio of permeability parallel to the major axis to the permeability perpendicular to this axis was 144:l and that it inclined along an angle of about 30". To prevent the reduction of sweep efficiency which would normally result from flooding or cycling in such reservoirs, well spacing could be varied from the customary square to a diamond-shaped pattern. Johnson and Hughes&apos; presented a method for determining the desired shape. Another method will be discussed in detail in the next section. It is the purpose of this paper to investigate quantitatively the effect of directional permeability upon the sweep efficiency and production capacity of the five-spot and line-drive well patterns. Information currently in the literature will be applied to this particular problem and augmented by a potentiometric model study. It is stressed that the effects herein discussed may or may not be of great importance because field data on this phenomenon are far too scant to form such an opinion. It is suggested that, if conditions similar to those found by Johnson and Hughes frequently exist (as may well be the case), more consideration cdrtainly should be given to this problem.

By W. J. Leas, L. A. Rapoport

As a preliminary, consicleration is given to the conventional definition of relative permeability and to the conditions governing the simultaneous flow of oil and gas through porous media. For the conditions of flow prevailing throughout most of a gas drive reservoir, the oil and gas can reasonably be supposed to be in capillary equilibrium with each other. Under these conditions, and these conditions only, the relative permeability to liquid can be expressed as a function of saturation. The relative permeability to liquid in that case is dependent upon the distribution of fluids which itself is shown to be related to the capillary pressure, and, in turn, to the saturation. As a consequence, relative permeability to liquid can be expressed in terms of the volume and surface area of a network of liquid channels bounded by the rock and the gas phase. While the volume of this network can be evaluated accurately, the surface area cannot. However, for any such volume, maximum and minimum values of the corresponding surface area can be calculated from capillary pressure data. It is then possible to establish for any saturation the limits within which the value of the relative permeability to liquid must lie. As a consequence of the theoretical development, the validity of an experimental method for measuring relative permeability to liquid which utilizes a stationary gas phase is demonstrated. In this method capillary barriers are cemented to the ends of the core sample to permit the maintenance of capillary equilibrium between the two phases. At the same time, this procedure eliminates undesirable secondary phenomena such as end effects, fissure effects, etc., the presence of which adversely affect the results of other laboratory methods. The results obtained by theoretical calculations, and experimentally, are discussed. In view of the overall precision that can presently be obtained in reservoir calculations, the agreement between the calculated and measured relative permeability to liquid data can be considered satisfactory. In conclusion, for reasons of economy and simplicity, the procedure of calculating limiting relative permeability to liquid curves from capillary pressure data is indicated for general engineering purposes. It is shown that the above procedure can easily be extended to the cases where connate water is present. Its use for reservoir studies is particularly recommended in conjunction with the method for measuring relative permeability to gas&apos; which simultaneously yields the capillary pressure data necessary for the calculations. THEORETICAL Definition of Relative Permeabilities — Basic Equations for Heterogeneous Flow The equations by which the relative permeability concept is defined and upon which the formulation of all of the gas-oil flow problems rests at the present time are expressed as: V, = — Grad PL = — Grad PL ....(la) PL µL, k k KG VG = —K - Grad PG k- Grad Pc .... (lb) Mo where ,. and G refer to liquid and gas; V is the volumetric rate of flow per unit gross area. µ the viscosity, Grad P the potential gradient. and k the specific permeability of the porous medium.* (For horizontal flow, Grad P becomes the pressure gradient; otherwise, gravity must be included.) According to these expressions, each of the constituent phases is considered similar to a homogeneous system where the volumetric rate of flow is proportional to the pressure gradient, and for each of which the constants of proportionality, k, and kG, are termed effective permeabilities. by analogy to the specific permeability as defined by Darcy&apos;s law in its original form. In order to obtain a convenient basis of comparison, the effective permeabilities are referred to the specific permeability, k, of the considered porous medium, with the help of the relations: k1. = KI. k kQ = Kn k..........(2) K,. and Kr. are defined as the relative permeabilities to the liquid and to the gas phase respectively, and frequently expressed in per cent of specific permeability. It may be seen that Equations (1); which appear to be a direct generalization of Darcy&apos;s law, correspond to the assignment at any given time of a set of "local" permeabilities to each point of the porous medium, and represent in a differential form the two fluid flow system as a simple superposition of the individual single flow systems. The above interpretation implies that the effective or relative permeabilities are independent of pressure or rate of flow,

Jan 1, 1951

By L. A. Rapoport, W. J. Leas

As a preliminary, consicleration is given to the conventional definition of relative permeability and to the conditions governing the simultaneous flow of oil and gas through porous media. For the conditions of flow prevailing throughout most of a gas drive reservoir, the oil and gas can reasonably be supposed to be in capillary equilibrium with each other. Under these conditions, and these conditions only, the relative permeability to liquid can be expressed as a function of saturation. The relative permeability to liquid in that case is dependent upon the distribution of fluids which itself is shown to be related to the capillary pressure, and, in turn, to the saturation. As a consequence, relative permeability to liquid can be expressed in terms of the volume and surface area of a network of liquid channels bounded by the rock and the gas phase. While the volume of this network can be evaluated accurately, the surface area cannot. However, for any such volume, maximum and minimum values of the corresponding surface area can be calculated from capillary pressure data. It is then possible to establish for any saturation the limits within which the value of the relative permeability to liquid must lie. As a consequence of the theoretical development, the validity of an experimental method for measuring relative permeability to liquid which utilizes a stationary gas phase is demonstrated. In this method capillary barriers are cemented to the ends of the core sample to permit the maintenance of capillary equilibrium between the two phases. At the same time, this procedure eliminates undesirable secondary phenomena such as end effects, fissure effects, etc., the presence of which adversely affect the results of other laboratory methods. The results obtained by theoretical calculations, and experimentally, are discussed. In view of the overall precision that can presently be obtained in reservoir calculations, the agreement between the calculated and measured relative permeability to liquid data can be considered satisfactory. In conclusion, for reasons of economy and simplicity, the procedure of calculating limiting relative permeability to liquid curves from capillary pressure data is indicated for general engineering purposes. It is shown that the above procedure can easily be extended to the cases where connate water is present. Its use for reservoir studies is particularly recommended in conjunction with the method for measuring relative permeability to gas&apos; which simultaneously yields the capillary pressure data necessary for the calculations. THEORETICAL Definition of Relative Permeabilities — Basic Equations for Heterogeneous Flow The equations by which the relative permeability concept is defined and upon which the formulation of all of the gas-oil flow problems rests at the present time are expressed as: V, = — Grad PL = — Grad PL ....(la) PL µL, k k KG VG = —K - Grad PG k- Grad Pc .... (lb) Mo where ,. and G refer to liquid and gas; V is the volumetric rate of flow per unit gross area. µ the viscosity, Grad P the potential gradient. and k the specific permeability of the porous medium.* (For horizontal flow, Grad P becomes the pressure gradient; otherwise, gravity must be included.) According to these expressions, each of the constituent phases is considered similar to a homogeneous system where the volumetric rate of flow is proportional to the pressure gradient, and for each of which the constants of proportionality, k, and kG, are termed effective permeabilities. by analogy to the specific permeability as defined by Darcy&apos;s law in its original form. In order to obtain a convenient basis of comparison, the effective permeabilities are referred to the specific permeability, k, of the considered porous medium, with the help of the relations: k1. = KI. k kQ = Kn k..........(2) K,. and Kr. are defined as the relative permeabilities to the liquid and to the gas phase respectively, and frequently expressed in per cent of specific permeability. It may be seen that Equations (1); which appear to be a direct generalization of Darcy&apos;s law, correspond to the assignment at any given time of a set of "local" permeabilities to each point of the porous medium, and represent in a differential form the two fluid flow system as a simple superposition of the individual single flow systems. The above interpretation implies that the effective or relative permeabilities are independent of pressure or rate of flow,

Jan 1, 1951

By Edwin Ludlow

THERE has been so much misinformation sent out through the newspapers, and I find so few people who are really acquainted with the true facts in regard to the coal strike, that I feel it would be advan-tageous to present the facts as I have been able to gather them. One of the great points that the miners are now mak-ing is the fact that the operators of the central competi-tive field, consisting of the states of Illinois, Indiana, Ohio and Pennsylvania, have refused to meet them in a joint conference such as has been customary in previous years. There are two reasons why the operators de-clined to hold such a meeting. In the first place, the last time they held a meeting of this kind they were all indicted under the Sherman Act for making an agree-ment in restraint of trade. In the second place, the miners at their convention did not authorize their dele-gates to negotiate a new contract, but instructed them that nothing less than a scale based on the present wage, with the addition that there should be a six-hour day, a five-clay week, time j and a half for over time, and double time for Sundays, would be accepted. These additions would very much increase the cost of coal over the present wage scale. The operators could not consider renewing a contract on the present scale, as it would mean ruin for them, and as the miners were not authorized to negotiate a new scale on a fair basis that would enable the operators to mine coal in competi¬tion, with the open-shop mines the operators did not feel that there was any use in meeting the delegates. Thirty per cent. of the output of bituminous coal comes from the open-shop mines of West Virginia, Alabama and Pennsylvania. During the strike, in 1919, this 30 per cent. was increased to 50 per cent. and it has affected the operations of the union mines to such an extent this year that they have been able to run only 15 to 30 per cent. of their time, while the open shop mines have run from 60 to 80 per cent. as the wages in these mines had been reduced to the 1917 scale.

Jan 5, 1922

By Frank Alfred Fahrenwald

MetallURgical research has discovered many an alloy possessing properties not combined in any single metal, and progress still consists chiefly in the investigation and utilization of alloys. In the case of iron, the demands of automobiles, high-speed machines and high-duty engines have led to the production of special iron alloys which will meet any reasonable specifications in that field. In like manner, the bronzes, brasses and other alloys of copper have been brought to remarkable perfection, and for nearly every industrial purpose some alloy has been , found more suitable than the pure metal. Less complete success has attended the attempt to find substitutes for gold, platinum, and the other precious metals. Indeed, it is not likeiy that a material can be produced which, will possess all the properties of any one of them; yet it is reasonable to hope that, for any given use, the properties required may be found in some less expensive material. Thus, in incandescent electric lamps, the wire passing through the thick glass neck of the bulb was, until recently, almost universally made of platinum, for the single reason that no other known material, suitable as a conductor, had the same coefficient of expansion as glass. But a comparatively recent investigation of the iron-nickel series1 has shown that alloys of those metals maybe produced, the coefficient of expansion of which can be accurately controlled between that of iron or nickel and zero. Thus, in that particular industry, a substitute for platinum has been found. According to statistical reports, not only considerable quantities of gold and iridium, but also more than one-third of the annual supply of platinum, are used (and, in the nature of the case, irrevocably lost) by dentists. Platinum is thus employed in several forms. As a thin foil, it serves various purposes for which its high melting point, pliability, chemical resistance, and other properties—including the ease with which it may be soldered—are invaluable. But it is most extensively used in

Jan 1, 1916

By W. N. Best

Crude oil attracted attention because of its excellence as a fuel for openhearth furnaoes; for making crucible steel and brass; for melting copper, lead, tin, zinc, nickel, silver, malleable iron, gray iron; and for the production of steam in all sizes and types of boilers. For heating furnaces, mold-drying ovens, core ovens, ore roasters, calciners, hotair furnaces, sand drying, asphalt road work, etc., its superiority over other fuels is due to the fact that the heat is at all times under perfect control, so that a constant temperature may be attained and maintained at the will of the operator. This mcans a maximum amount and uniform quality of work. Crude oil is of two kinds, paraffine base and asphaltum base, and varies from 11 to 46 gravity BaumB. The light-gravity oil does not require heating before use; but oil of less than 20 gravity Baumé should be heated to just below its vaporizing point, in order to reduce its viscosity and to obtain the highest efficiency of combustion. Heavy California oil vaporizes at 230". F., Mexican crude oil at from 175" to 210" F., and Beaumont, Texas, oil at 142" F. Fuel oil vaporizes at 130" F. Scientific Installation Essential The burning of oil is an art based on science, and the "rule of thumb" should never be employed, especially in heating heavy crude oil. Thermometers should be used on both suction and supply pipes so that the fireman or smith will at all times know the temperature of the fuel. The indicators on such thermometers should be large enough to be readily seen by the operator, night or day. It is necessary to have an unvarying pressure of steam or air through the burner, to atomize the fuel. Also, the air used to support combustion should be delivered through a nozzle under the burner at a constant pressure. The oil pressure must not fluctuate; under no eircumstances should it vary more than 1 1b. The oil pump, which should be brass-lined, with the aid of the pulsometer and superheater, will insure a constant

Jan 1, 1916

By P. Gobin, J. Perez, P. Peguin

The strain-amplitude- dependent part of the internal friction of alluminum after several ther momechanical treatments has been measured in the I-cycle range and at the ambient temperature. The internal friction in the outer layer of the torsional specimen us stress is computed from the experimental data. The curues obtained are analyzed in tevnzs of u coirzbinntion of AH and p, which aye, respectively, due to the vecersible unpinning from weak pills and to the plastic strain. Considerirlg the notion of thermally activated unpinning and repinning, it is shown that in our experimental conditions tlze dislocation lines acl as in the H model of Granato and Liiclze. It is also seen that the internal friction p which appears at higher- strains call be described by a simple expression which is in good agreement with our results. A qualitative interpretatiorz is proposed by combining these new types of intelpnal fviction. We define the internal friction 6 as half the ratio of the dissipated energy aW during one cycle to the maximum supplied strain energy W of a material submitted to a periodic stress. Experiment and theory show that internal friction varies with stress above a critical value.&apos; Below this value the internal friction is strain-amplitude-independent and is often masked by an experimental background; so we shall call it AB. ~bove this critical value, the internal friction is strain-amplitude-dependent. This quantity is usually called aH:&apos; and it can be explained as a thermal unpinning of dislocations.3-6 Furthermore, at higher stresses, a rapid increase of internal friction appears. This phenomenon could be caused by the plastic strain,&apos; so we shall call it Ap. It seems interesting to us to study the influence of several t her momechanical treatments on the curve internal friction 6 vs strain E, in order to study the variation of AH and p with the concentration and the repartition of linear and point defects. In order to try to explain the results obtained, we shall propose and discuss models for H and hp and shall show that we obtain a combination of these two types of internal friction. 1) EXPERIMENTAL PROCEDURE 1) Preparation and Treatment of Specimens. We

Jan 1, 1968

By Thomas L. Garwood, F. C. Menk

IT is generally, accepted that no method of coal cleaning except froth flotation is effective in cleaning dust. In the majority of coals mined in the United States the dust sizes contain a high percentage of impurities, hence the removal of the dust from the coarse sizes lowers the impurity content of these sizes. Dedusted coal is desired as a means of providing a better feed to cleaning plants because of increased efficiency in both dry and wet plants. In dry-cleaning plants, a dedusted feed makes for a pervious and uniform bed. With a dusty feed the fines tend to segr6gate in the feed stream and pass en masse over the air separators, causing a lack of uniform aeration and fluidity of the bed necessary to efficient cleaning. In wet-cleaning plants dedusting of the feed often decreases the sludge problem to the point of eliminating the necessity of wasting wash water. It may be advantageous to eliminate sludge-settling equipment in favor of dedusting equipment, to provide the advantages of a dedusted feed to the wet-washing process. Dedusting advantages may include: (1) the removal of fusain, especially advantageous in plants washing coal intended for metallurgical coke; (2) prevention of the gradual build-up of solids in the wash water, with a consequent variation in the washing ability of the system; (3) prevention of the loss of dust to the sludge ponds, providing instead a fuel for local consumption or special markets. DEDUSTING The practice of dedusting, sometimes called aspirating, has presented a problem in disposing of the dust and intermediate small sizes recovered in the process. It has been found that no difficulty is experienced in disposing of the intermediate sizes, since they are free of fine dust and burn freely on grates built for small coal. They handle well, flowing freely from bins and hoppers and into conveyors, and pulverize easily. They have a low angle of repose. In tests made on this size as a feed to coke ovens, the results have been excellent, in that the natural breakdown of .coal in handling and shooting in the mine gives this small-size coal good

Jan 1, 1943