Search Documents

West Virginia Geological Survey Morgantown, W. Va James D. Sisler, State Geologist. Of great importance among the publications of this Survey have been the volumes of Detailed Reports on the counties of the state These volumes take up in detail the geology, topography, soils and resources of the areas under consideration; they are profusely illustrated and each carries topographic and geologic maps Detailed Reports are available for areas as follows: Marshall, Wetzel and Tyler counties (1911) $3, Wirt, Roane and Calhoun counties (1911), $2 50, Jackson, Mason and Putnam counties (1911), $2, Cabell, Wayne and Lincoln counties (1912), $2 50, Doddridge and Harrison counties (1912), $2 50, Monongaha, Marion and Taylor counties (1913), $2 50, Kanawha County (1914), $2 50; Preston County (1914), $2, Logan and Mmgo counties (1915),12 50, Boone County (1915), $2, Wyoming and McDowell counties (1915), $2 50, Lewis and Gilmer counties (1916), $2 50; Raleigh County, Summers west of New River, and the coal area of Mercer County (1916), $2 50, Jefferson, Berkely and Morgan counties (1916), $2 50, Braxton and Clay counties (1917), $2 50; Barber and Upshur counties, and western Randolph County (1918), $3; Fayette County (1919), $3 25;

Jan 1, 1933

Solution mining got back in the news recently when Kalium Chemicals, Ltd., a joint subsidiary of Pittsburgh Plate Glass and Armour & Co. announced its plans to go full speed ahead in mining potash by the solution method in its vast holdings 30 miles west of Regina, Saskatchewan. The company is keeping the technical details of this mining technique under wraps for competitive reasons, but company officials insist that the major difficulties in solution mining of potash have been overcome and that the final product will have definite competitive advantages on the open market. Kalium's holdings in the Regina area total about 500 sq mi. The ore-primarily sylvite mixed with appreciable quantities of halite-occurs in the Prairie Evaporite formation at a depth of 5300 ft. The ore zone averages about 100 ft in thickness. Too deep to be economically mined by conventional underground methods, such as is being done at International Minerals & Chemical Corp.'s Esterhazy mine (depth about 3100 ft), Kalium gambled that it could develop a successful method of solution mining even though earlier attempts in Germany, the U.S., and Canada had failed.

Jan 6, 1964

By John F. Shaw

The Denver Mining Research Center headquartered at Denver, Colo., is typical of the new research units recently activated as a result of increased emphasis by the U. S. Bureau of Mines on research concerned with metal and nonmetal (except mineral fuels) ore extraction. The Denver Center, together with the recently established Minneapolis Research Center and the Offices of Mining Research at Reno and Spokane, and the older, well-known Applied Physics Research Laboratory at College Park, Md., share the responsibility for the comprehensive mining research program. The Denver Center specializes in two areas of research: (1) The development of engineering principles and mathematical techniques applicable to exploration, development and operational problems in mining, and (2) the study of rock mechanics as applied to ground control. The first area presently includes three categories: research on methods of ore sampling, mine-systems analysis, and applications of statistics to problems of mineral exploration. The second area emphasizes research in two main categories: laboratory investigations designed to develop a fuller understanding of how rock be- haves under the loads imposed by mining, and field investigations to evaluate stress-strength relation- ships in full-scale, operating mines.

Jan 3, 1962

By Thomas M. Plouf

Flotation, as we know it today, is a physiochemical method of concentrating finely ground ores. The process involves chemical treatment of an ore pulp to create conditions favorable for the attachment of certain mineral particles to air bubbles which are carried to the surface of the ore pulp for removal. Frother reagents, combined with air and the agitation mechanism, produce the effective bubbles in a flotation cell. A method of analysis is presented to evaluate the effect of frother reductions and additions on a bank of flotation cells, and to economically determine if and to what extent frother reductions and additions are justified. Comparative evaluations of different frother systems, as well as the amount of frother used in a given flotation machine, cannot be made on the frother cost alone. An indepth study must be made to evaluate any given frother as applied to a particular ore body. The recovery of a given mineral is as dependent on the amount of frother as on the type of frother used. An actual case study follows in which the amount of frother required by two different flotation machines was used to make a decision as to which unit performed more efficiently based on costs. This same method may be used to evaluate new frothers as well as to determine if a larger frother addition is advisable.

Jan 11, 1975

By Carl Henrich

A.. S. DWIGHT, New York, N. Y.-Mr. Henrich's paper is rather inconclusive as to the role that alumina really plays in slags. He gives a number of interesting instances of high alumina, with conclusions that he draws from the analyses, in the light of what he knows of the accompanying conditions, but the information given is hardly sufficient to permit intelligent criticism of these conclusions, for it is well known that the slag composition is not the only factor that can produce some of the furnace results favorable or disastrous, as the case may be, which he records. As a matter of fact, most metallurgists who have wrestled with this problem in connection with the smelting of lead and copper ores, usually arrived at some sort of a working hypothesis which met the local conditions fairly well, and then, being busy men, were inclined 'to leave the theoretical question very much as Mr: Henrich leaves it when he says: "A question with which I purpose dealing at some future time." It is unfortunate that in the Golden Age of the smelting industry in the West, when we were all dealing with large tonnages of complex ores, often containing large percentages of alumina in combination with other. refractory elements, the smelting companies were not generally equipped for research as they are today, and much experience that might have been,

Jan 4, 1917

By K. C. Carriere

INTRODUCTION The purpose of this section is to introduce the reader to the concepts of computer control of grinding circuits, and to flag some of the opportunities to be encountered, but without becoming overly involved in details of process, equipment or software. It is assumed that the reader has some familiarity with computer hardware and software, and in particular with the grinding process. The paper is organized into four parts: a general commentary of the need for computer control of grinding, a discussion of the process considerations involved, a more detailed elaboration on the current state of applicable computer technology, and a case study indicating one approach towards such a project. A brief installation survey and references for further reading are also given. This section will primarily deal with supervisory computer applications. Direct Digital Control and microprocessor systems are generally used as replacements for analog controls and thus are not considered in depth. Many configurations of grinding circuits exist, necessitating certain assumptions. Since many new concentrators use an open circuited SAG mill feeding a closed circuit ball mill, this configuration is used as a model although the principles stated can be extrapolated to any circuit. Motivation The use of computers for industrial control has been one of the dreams of control engineers and operators alike for many years. The concept of a plant running at optimal conditions with minimal operator involvement is very attractive from economic and technical standpoints. Accomplishment of this goal has been a long struggle, but today likelihood of success of such a project is very high, considering the reliability of modern hardware and the sophistication of available software. The primary motivation of any control system must be economic, i.e. it must pay for itself and make money for the owner, directly or indirectly. In grinding control the benefits which can be expected include: a) Higher through-put b) More uniform product in particle size, density and volumetric flog: c) Reduced operating costs including media consumption, power consumption and liner wear

Jan 1, 1982

By Carroll F. Hardy

THE position of the coal industry has been affected by a wide variety of developments in the production and use of energy. The tempo of development and change has been increasing and the end is not in sight. Legislation is currently being proposed for commercial use of atomic power, and the employment of atomic energy in significant quantity will probably occur about the same time as the decline in production of petroleum and natural gas. But these developments are in the future and have little immediate effect on utilization and marketing of coal. While no one should try to suppress or retard the development of a new and economical source of energy, both the coal and private utility industry should be allowed to question how the nuclear power is to be used, who is to use it, and who is going to pay for it. The taxpayers have a monopoly on fissionable material and the knowledge to employ it. Any commercial use must stem from this source. It is not hard to visualize either taxpayer- subsidized private utility atomic power plants on one hand and super TVA's on the other. In view of the gains of gas and oil in the home heating field, it is interesting to compare the 1940 and 1950 census reports on the kind of fuel used for heating in occupied dwelling units. Table I shows that whereas coal provided 77 pct of the fuel for central heating (furnaces and boilers) in 1940, it was down to 45.4 pct in 1950. However, only about 1 ½ million units were lost in this 10-year period.

Jan 3, 1954

By Frank Harwood Riddle

Products made from the ores of the sillimanite group, and synthetic substitutes for them, have unique properties, and service tests prove that they are playing, and will continue to play, a major part in improvements in metallurgical processes. Also, they are examples of how comparatively useless, rare, or "museum" minerals have been made available in commercial quantities. Until research developed uses for them, the minerals had been observed only in small, scattered masses, or crystals. Improvements in ceramic processes and compositions have come about very gradually. In the last 10 or 15 years, several outstanding developments have been made. Of greatest interest to the mining and metallurgical engineers are those affecting the composition, necessitating the mining of new minerals, and improvements in ceramic products used in metallurgical processes. Sillimanite and Mullite Sillimanite (Al2O3.SiO2), then known as Fibrolite, according to Dana,' was first reported in 1792. In 1796, cyanite (Al2O3.SiO2) was first described.2 In 1873, Behrens published results of his microscopic study8 of porcelain. He showed that it contained what appeared to be crystals, which dissolved less readily than quartz and glass in hydrofluoric acid. Hussak4 described the presence of needlelike crystals as occurring in some instances in small amounts in certain porcelains. In 1908, Plenske and Zoellner both studied porcelain structure.5 Plenske observed that "sillimanite" might be present in masses of exceedingly minute grains which apparently were amorphous. Zoellner advanced the theory that the needlelike crystals were formed by a molecular change in the clay,

Jan 1, 1932

By Thomas H. Sheldon

In the zeal for opening up new ore-bodies, or for extracting the ore from attractive bodies already opened up, we very often lose sight of the fact, that, after all, the operation of a mine is a business proposition, pure and simple, and, for the best working-results, should be treated upon a strict business basis. Of course, in every mine of consequence, a record is kept of expenditures and receipts, and such glittering generalities as " gross receipts," " net receipts," " mining expenses," and a per cent. profit," can be told to the cent; but does this record show economy of management, as compared either with the same record of other months, or with the record of other mines of the same class ? Moreover, if such a record shows that the cost of mining is high, does it in any way enable the manager to put his finger on the leakage ? Does it necessarily follow that a mine which makes a profit of, say, 40 per cent. on 25-dollar ore, is doing less economical mining than one which saves 60 per cent. on 80-dollar ore ? Of course the figures in the latter case look the more attractive; yet when it comes to the point of saving everything which can be saved, and of cutting down expenses to the lowest possible cost of operation, the former mine is doubtless on the firmer and more economical financial basis. But as to the relative merits of the system of mining in the two cases, nothing could be decided without a basis of detailed comparison ; if one system is more economical than the other, why is it so, and wherein does the advantage lie ? This can be shown only by keeping accurately the cost of each mining operation. And no matter how dissimilar two mines may be in character and operation, yet there are a few general heads common to all mining operations. In the first place, it is necessary to break the ore from the solid ground;

Jan 1, 1907

By J. S. Marsh

OPPORTUNITY to pay tribute to the memory of Professor Henry Marion Howe is a strenuous assignment as well as an honor. Upon recalling Howe lecturers and lectures of the past 25 years, glancing over the list of those earlier, and rereading Howe's books, I arrive at several conclusions: 1—Many lecturers either worked under or knew Professor Howe. 2—It is virtually impossible to pick a subject on which Professor Howe did not touch. 3—There is precedent for a technical paper based upon pursuit of a single subject. 4—There have been listening lectures and reading lectures. There is solid comfort only in 2: the subject field is wide open. I did not know, nor even ever saw, Professor Howe, so can supply no fitting reminiscence. As a college student I was dimly aware that he counted among the giants. Fuller appreciation of his stature came with reading his books and papers, growing acquaintance with some of his associates, and the intrinsic dignity of the climax of the Annual Meeting, beginning at four o'clock of a Thursday afternoon in the auditorium of the Engineering Societies Building in New York. As for producing the technical paper sort of thing, it is my lot to have reached an age and assignment such that to do so would be to filch information from those who did the work and whose story is theirs to tell; for this I have no enthusiasm. As for the final conclusion, Professor Howe was one of the chosen few so highly expert at expository writing that he could produce a lecture or paper that reads as though it would also have listened well. One of his tricks was the free use of words not ordinarily part of the technical vocabulary, provided that such words were likely to communicate most precisely what he had in mind. How wonderful it would be for all who must read reports by the ton if ability at exposition could be taught with the effectiveness open, say to, differential calculus! Perhaps Professor Howe should be required college reading even if for no other reason than to prove that technical writing need be neither dull nor diffuse. My assignment is clearly still strenuous. Another point to consider is the fact that metallurgy is now so tremendously diversified that hope of finding a topic of universal appeal is negligible, even if one were competent enough to be permitted free choice. That which follows is, therefore, a compromise composed of necessity and of the obligation to attempt to avoid boring to slumber those of you who are not especially interested in the general subject chosen. The Iron and Steel Div. is now essentially a process metallurgy division, heavily concerned with the smelting of iron and the making of steel. The American Iron and Steel Inst. figure for present steel capacity of this country is 125,828,310 net tons; how this is divided among processes is indicated by the production totals for 1953, shown in Table I. The glamor girls and boys make the front page and so it is with steelmaking processes. If there is an Antarctic Daily Bugle, it undoubtedly has carried stories of revolutionary development, such as oxygen processes and vacuum melting, and stories of the incomparably rosy destiny of electric arc melting. All such certainly have their place and their future; meanwhile, it is the sturdy and old reliable open hearth that accounts for the bulk of production reported back on the financial page, and it is the old reliable that is most likely to continue to account for the bulk for some perfectly sound raw material, technologic, and economic reasons. This, plus the fact that next year marks a centennial (for it was in 1856 that Frederick and William Siemens conceived the regenerative open hearth), is reason enough to talk about open hearth furnaces, but is not the real one. The real reason is that in some years of association with open hearths, I have accumulated—in addition to a genuine liking and respect for them—certain odds and ends of fact and fancy that this lecture provides a unique chance

Jan 1, 1956

The regular meeting of the Trustees of United Engineering Society was called to order at 4 P. M. Thursday, Feb. 27, 1919, in the Board Room of the American Society of Civil Engineers, Engineering Societies' Building, New York. Minutes of a joint meeting of the Finance Committee of United Engineering Society with finance committees of Founder Societies on Feb. 14, were presented. The President called attention to actions relating to the recataloging of the Library and the support of Engineering Societies Employment Bureau of Engineering Council. The activity of the Employment Bureau was approved and support by the Societies informally assured. In response to a communication from the Fifth Avenue Association, the Secretary was instructed to write favoring the continuance of the daylight saving law. As to recataloging of Engineering Societies Library, it was announced that the Mining, Mechanical, and Electrical Engineers had voted appropriations, as requested, and the action of the Civil Engineers was awaited. A list of applications for offices in Engineering Societies' Building, revised to Feb. 27, was read, showing requests for a total of 29 rooms. The President stated that a decision must be reached soon as to what reply shall he made to these applications. Charles F. Scott, one of the original trustees, who was present, remarked upon the growth of United Engineering Society and his satisfaction at its success. ALFRED D. FLINN, Secretary.

Jan 4, 1919

By Carlos G. Valenzuela

The value generally accepted for stacking-fault energy, of copper has been approximately 40 ergs per sq cm based on Fullman's2 value for the coherent twin-boundary energy and the assumption that is twice the twin boundary energy However, Thornton and coworkers8 determined that the lower limit of for copper is approximately 60 ergs per sq cm, based on measurements of dislocation-node radii. They suggested that the assumption of = 2t is invalid. It is the purpose of this note to present results which indicate that the values of obtained by measurement of twin-grain boundary intersections and the values obtained by measurement of dislocation-node radii are actually compatible. The most reliable values for of the a brasses, based on electron-microscope observation of dislocation nodes, are probably those values reported by Smallman and Green6 who applied the Siems correction (1961) to data obtained by Howie and Swann.3 These values shown in Fig. 1 give an extrapolated value of approximately 70 ergs per sq cm for pure copper. In the present work, Fullman's method for determining the stacking-fault energy of copper was extended to the a brasses. High-purity copper (99.999 pet) and high-purity zinc (99.999 pet) were mixed in proportioned amounts and melted in sealed and evacuated quartz tubes. The alloys were homogenized for a week at 750°C and chemically analyzed by means of X-ray fluorescence. These alloys, along with a specimen of pure copper, were rolled to 98 pet reduction and a thickness of 0.009 in., resealed, and annealed for 40 hr at 715°C. Values for the ratio of twin-boundary energy to the grain-boundary energy, it gb, were obtained from measurements of dihedral angles formed at the intersections of twin boundaries and grain boundaries by using Fullman's2 mechanical analogy of surface tensions acting at the intersection of an annealing twin and a grain boundary. The angles between the twin traces and the grain boundaries were measured for a large number of twin-grain boundary intersections at a magnification of X500 using a rotating mechanical stage on a Reichert metallograph. The rotary stage has a calibrated angle scale with vernier so that measurements can be made to 0.1 deg. The mean twin-grain boundary energy and standard deviation were calculated for copper and each of the brasses by the use of an IBM 7072 computer. It was found that the mean value of gb stabilized after approximately 100 twin-angle measurements. This was determined by plotting the mean against the number of angles measured. Since the measured angles deviate from true dihedral angles, a correction factor for grain orientation, discussed below, was applied. The stacking-fault energy was then calculated from these values and the values of grain-boundary energy derived by Taylor.7 The data obtained are tabulated in Table I. Values for stacking-fault energy are plotted in Fig. 1. The value of gb for the specimen of 1.03 pet Zn is close to the value obtained by Fullman2 for OFHC (99.98 pet) copper, 0.045. It is believed that the purity of the copper affects gb significantly. The 99.999 pet purity Cu used in this investigation yielded a value of yt/ygb, 0.76, which is much higher than that obtained by Fullman. Additional evidence suggesting that the purity of

Jan 1, 1965

By Michael B. Bever, Barton Roessler

The effects of deformation by wire drawing at 78OK on initially ordered and initially disordered specimens of the alloy Cu3Au were investigated. The resistivity, stored energy, drawing force, and microhardness were measured as functions of strain; microstructural changes were observed. The results are interpreted in terms of the structural imperfections and the changes in atomic configuration resulting from deformation. A few experiments on the effects of room-temperature annealing after deformation at 78°K were made; they suggest vacancy-promoted ordering in disordered alloys. BARTON ROESSLER, Junior Member AIME, formerly Graduate Student and Alcoa Fellow, Department of Metallurgy, Massachusetts Institute of Technology, Cambridge, Mass., is with Westinghouse Research Laboratories, Pittsburgh, Penn. MICHAEL B. BEVER, Member AIME, is Professor of Metallurgy, Massachusetts Institute of Technology. Based in part on o thesis by B. ROESSLER submitted in October, 1959 to the Massachusetts Institute of Technology in partial fulfillment of the requirements for the degree of Doctor of Science. Manuscript submitted April 6, 1961. IMD AN investigation of the effects of deformation at room temperature on the alloy Cu3 Au was reported in a recent paper,' which included a review of the literature on the deformation of order-disorder alloys. In general, plastic deformation of ordered alloys reduces the degree of long-range order and causes corresponding changes in their properties. Deformation of disordered alloys changes their properties in a manner characteristic of solid solution alloys; these changes can in part be attributed to the destruction of short-range order. The effects of deformation on solid solution alloys are of two kinds: 1) generation of structural imperfections, which occurs as a result of deformation in any metallic system including pure metals, and 2) changes of atomic configuration, which are characteristic of solid solutions and particularly of order -disorder systems. These two types of effect are not independent of each other and the state of a deformed solid solution alloy is determined in a complex manner by the way in which the structural imperfections cause changes in atomic configuration both during and after deformation.

Jan 1, 1962

By M. H. Loveman

THE orebody described below has been rediscovered and developed within the last 3 years. It has, however, been known and worked by the Chinese for hundreds of years. When assay values and size are considered, it contains what is probably one of the largest single bodies of zinc and lead sulphides yet found. The tonnages developed at other places, as at Broken Hill, are much greater but the average zinc and lead sulphide contents are considerably lower than at Bawdwin. Bawdwin is situated in the semi-independent State of Tawng Peng, one of the numerous units which make up the Northern Shan States. These States are under British rule and are generally considered as a portion of Burma. They are governed as a separate administrative unit, however, under the Lieutenant Governor of Burma. Each State is under its own chief, or Sawbwa, who has considerable power over his own subjects. Bawdwin is approximately in latitude N 23°6', longitude E 97°20', about 50 miles south of the nearest point on the Chinese border and 450 miles north of Rangoon (Fig. 1). The period at which mining was first begun at Bawdwin is unknown. The most reliable records have been obtained by deciphering local Chinese inscriptions and from these it is concluded that the work dates back to at least the beginning of the 15th century. The first undoubted reference to the mines by a European is by Symes in 1795. Crawford in 1827 estimated the output of silver from the mines at $600,000 annually. At about the middle of the 19th century the rebellion of the Chinese Mohammedans in the neighboring Chinese province of Yunnan so weakened the power of the Chinese that the incursions of hostile tribes (Kachins) made work extremely dangerous. The mines were finally abandoned by the Chinese about 1868. The closing down of the mines was probably not entirely due to outside causes but may have been influenced somewhat by the increasing difficulty of handling the water, as the workings gradually descended below the water level of the district. Several attempts were made by the Burmese kings, Mindon Min and Thebaw, to resume operations, but because of a

Jan 12, 1916

By Y. C. Liu, R. H. Richman

From rolling textures of polycrystalline AgCl determined as a function of temperature, changes in the amounts of the individual textural components are correlated with temperature-dependent changes in glide geometry. The preferred orientations are influenced by the slip behavior as follows: 1) pencil glide, characterized by (110) slip directions and a greater participation in the deformation the higher the temperature, leads to a(012) fiber texture; 2) low-temperature deformation, primarily on (110) (110) systems, generates the {237}-(11, 9, 7) component; and 3) slip on {111}(110), comprising a significant portion of the room-temperature deformation, generates the {135}(211) and {110}(112) components. Typical re crystallization textures are also presented and briefly discussed. SPECIFIC relations between flow mechanisms in crystals and the individual orientations or components in deformation textures are necessary for a thorough understanding of the origin of such textures. Within each ordinary class of crystal struc- tures there is insufficient variety in the observed preferred orientations to permit direct and unambiguous correlation between flow mechanism and texture. A second approach to this problem is the correlation of textural changes with some known variation in glide geometry within one substance,1 In this paper, the latter approach is applied directly to a material in which there are distinct changes in the character of glide with changes in temperature. Silver chloride, although a nonmetal, is reported to exhibit slip,2,3 fiber textures,4 and rolling textures5,6 crystallographically similar to those of the well-studied fcc metals;7,8 in addition, there is a marked temperature sensitivity of the glide planes upon which flow occurs.3 Previous investigations of textures in AgCl unfortunately did not employ methods sufficiently sensitive to define possibly important minor components in the texture, nor did they utilize the temperature dependence of the glide systems. Thus, in order to clarify the effects of changes in slip mechanism, this paper reports a survey, using semiquantitative methods, of preferred orientations in rolled AgC1. Inasmuch as the influence of prior deformation texture upon preferred orientations after annealing is also of interest, some representative annealing textures are presented.

Jan 1, 1965

By Harold W. Scott

Geological Engineering is now a recognized curriculum in most of the mining schools in United States. Graduates of these schools are scattered over the face of the earth, participating in exploration and mining enterprises of diverse character. They are engaged in the mapping of new mineral deposits, in the extension of old deposits, the estimation of reserves, microscopic analysis, and in the direction of exploitation and conservation of man's natural resources. The training of men qualified to carry out these technical phases of modern industry has fallen essentially to the mining schools. For the most part they have met the demand for technically trained men in the mineral industries. Schools Offering Geological Engineering Degree The mining schools have passed through the early stages of their development and at the present offer varied curricula covering the fields of geological engineering, mining engineering, and metallurgical engineering. Usually a B.S. degree is offered in any of these three fields. However, .there has been some tendency of recent date on the part of the Engineers Council for Professional Development to question the validity of a B.S. degree in Geological Engineering. The of this paper is to examine the curricula as offered in the mining schools, to evaluate their engineering content, and to propose minimum requirements for the degree of Geological Engineering in the mining industry. The curricula of eight institutions that offer the degree of B.S. in Geological Engineering or Mining Geology have been studied (Table 1). All except one of these schools are in or near mining districts and occur west of the Mississippi River. They are all state-supported institutions that have come into existence because of the state's need for technically trained men. A graduate from .a mining school is called upon to perform many duties of a technical nature. His initial task may be to make a geological map of a mine or the surface above, but before the map is finished he may be asked to take over the responsibility of getting the ore "on top." And finally, he might find it essential to know how to mill the ore. Certainly this requires technically trained men and the mining schools are essentially the organizations to do the job. The departments of geology in these schools are training geological engineers. Field Of Geology If we were to accept the opinions of some writers, we would be forced to conclude that all geology departments offer only a "dilettante" variety of subjects.

Jan 1, 1944

By C. O. Worden, E. K. Landgraf, C. A. Zapffe

Following the discovery of Parke and Ham that deoxidation control of cast molybdenum can be predicated upon simple fractographic examination, a special study of that metal was undertaken to investigate those patterns ascribed to forge-ability and nonforgeability. An elaborately developed system of cleavage patterns immediately rewarded the study; and they are reported here as a necessarily preliminary contribution calling attention to information which is both new in type and in origin. In general, the present observations confirm those of Parke and Ham, and Wood-side; but they also disclose a wealth of detail and correlated phenomena which greatly expand the earlier information. For example, the oxide pattern of nonforgeability is found to be complex, perhaps involving as many as three distinctive patterns, And the nature of the carbide seems to be at least twofold. In addition, transgranular facets are here shown for the first time. Elaborately complex, but in a characteristic manner, these facets depict distortion in original crystal growth which provides truly extraordinary patterns. No carbide and oxide forms display themselves transgranularly, except in profile as exceedingly thin superficial films at the grain boundaries. Crys-tallographic features are also rare—a condition undoubtedly resulting from the great substructural distortion; but occasionally registrations are found of cleavage on {00I}, and faulted areas believed to be Neumann-type deformation on I I121. Introduction Parbe and Ham,' and again Woodside,2 have reported that the forgeability of molybdenum cast by their Vacuum-electric-arc Process can be predicted with great dependability by a simple fractographic observation. They state that nonforgeability is the result of a grain boundary oxide which can be readily identified on the fracture facet at high magnification; and they convert the nonforgeable condition to a forgeable one by increasing the carbon content of the melt until the oxide structures subsequently observed in the fracto-graph become replaced by a second strongly marked pattern characteristic of carbide and coincidentally indicative of forgeability. Considerable importance immediately attaches to such observations: (I) because of their direct commercial application to one of metallurgy's inviting and relatively unexplored metals; (2) because of a general scientific curiosity regarding the nature of these characteristic markings; and (3) perhaps more important, because of

Jan 1, 1949

By T. D. Mueller

Many investigators have used the response of the "dimensionless aquifer" to a unit pressure drop or a unit fluid-withdrawal volume to calculate the performance of an aquifer in supplying water influx to an oil reservoir. In the past, these response functions have been calculated with the aid of the Laplace transform. With the advent of ultra highspeed digital computers, it becomes practical to solve for the response functions with finite-difference techniques. The computer method also permits extension of the dimensionless-aquifer concept to include the nonhomogeneous aquifer wherein the permeability and other properties vary as a function of the space co-ordinates. This paper gives results of calculating the response functions for a series of nonhomogeneous aquifers. Response functions are presented for both linear and radial aquifers whose thickness, permeability-viscosity ratio and porosity-compressibility vary. These functions are new and should prove useful to the petroleum engineer in analyzing the behavior of nonbomogeneous aquifers. Results are presented in the form of charts that can be easily used by the field engineer. INTRODUCTION Aquifers which surround many oil and gas reservoirs have the ability to supply water influx to such reservoirs as oil and gas are withdrawn. This water influx, called natural water drive, provides one of the most effective driving mechanisms for the production of oil and gas. In producing a reservoir, therefore, it behooves one to make the maximum use of natural water drive. To achieve the maximum use, the reservoir engineer must be able to predict the performance of an aquifer under a variety of production schemes that may be proposed for the reservoir. Unfortunately, the physical properties which dictate aquifer behavior often are known only within limits. Seldom do wells penetrate the porous strata of the aquifer. Even when they do, quantitative information regarding porosity, permeability and water compressibility is seldom available. It is known, however, that the water efflux from most aquifer systems is governed by a single, relatively simple, linear, partial differential equation. Also, the general physical location of the aquifer boundaries often are known. A technique originall proposed by Hurst1 and van Everdingen and Hurst2 has been found useful in analyzing reservoirs in this situation. The idea was later expanded by van Everdingen, Timmerman and McMahan3 to include the mathematical technique of least-squares fitting. This latter method will be referred to as the VTM method. The basic assumptions of the VTM method include the following. 1. The location of the physical boundaries of the aquifer are known. 2. The flow conditions at these physical bound-daries are also known. 3. The aquifer is homogeneous; e.g., thickness, permeability, water compressibility and porosity are constant throughout. In the VTM method, a material balance is made on the fluids entering and leaving the reservoir. In the balance equations, the water-influx term is represented as the product of the water influx from an arbitrarily-selected, dimensionless aquifer system times an unknown conversion number. This balance can be formed as many times as there are data points in the history of the reservoir. Each time, the conversion number can be evaluated. If the reservoir engineer has picked the correct dimensionless aquifer to represent the real aquifer, the conversion number remains constant for all balances that have been made over the history period. If such a situation occurs, the reservoir engineer can then predict the performance of the reservoir for any type of production scheme by using the function associated with that particular dimensionless system and the derived conversion number. These functions will be referred to as the response function of the aquifer. If the aquifer is nonhomogeneous (e.g., if the porosity, permeability, thickness, porosity, or

By A. R. Orban, R. B. Engdahl, J. D. Hummell

The initial phase of a research program on smoke abatement from Bessemer converters is described. In work sponsored by the American Iron and Steel Institute, a 300-lb experimental Bessemer converter was assembled to simulate blowing conditions in a commercial vessel. Measurements of smoke and dust were also made in the field on a 30-ton commercial vessel. During normal blows the dust loading from the laboratory converter averaged 0.51 lb per 1000 lb of exhaust gas. This was similar to the exhaust-gas loading of a commercial vessel. The addition of hydrogen to the blast gas of the laboratory converter caused a decided decrease in smoke density. Smoke was also reduced markedly when methane or ammonia was added instead of hydrogen. The research is continuing on a bench-scale investigation of the mechanism of smoke formation in the converter process. DURING the past 2 years, on behalf of the American Iron and Steel Institute, Battelle has been conducting a research program on the control of emissions from pneumatic steelmaking processes. The objective of the research program is to discover a practical method for reducing to an unobjectionable level the emission of smoke and dust from Bessemer converters. PRELIMINARY INVESTIGATION Although conceivably some new collecting technique may be devised which would be economically practicable for cleaning Bessemer gases, no such system based on presently known principles seems feasible because of the extremely large volume of high-temperature gases involved. Hence, the research is being directed toward prevention of smoke formation at the source. A thorough review was first made of former work to determine the present status of the cleaning of converter gases. No published work was found on work done in the United States on collecting smoke or on preventing its formation in the bottom-blown, acid-Bessemer converter. In Europe, however, a number of investigations have been made on the basic-Bessemer converter. Kosmider, Neuhaus, and Kratzenstein1 conducted tests on a 20-ton converter to obtain characteristic data for dust removal and the utilization of waste heat. They concluded that because of the submicron size of the dust, special equipment would be necessary to clean the exhaust gases. Dehne2 conducted a large number of smoke-abatement experiments at Duisburg-Huckingen in a 36-ton Thomas converter discharging into a stack. A number of wet-scrubbing and dry collectors were tried unsuccessfully. A waste-heat boiler and electrostatic collector with necessary gas precleaners was felt to be the best solution for this particular plant. Meldau and Laufhutte3 determined that the particle size was all below 1 µ in the waste gas of a bottom-blown converter. Sel'kin and zadalya4 describe the use of oxygen-water mixtures injected into a molten bath in refining open-hearth steel. They claim that with use of oxygen-water mixtures the amount of dust formed was reduced between 33.3 and 20 pct of its previous level, and emission of brown smoke almost ceased. Pepperhoff and passov5 attempted unsuccessfully to find some correlation between the optical absorption of the smoke, the flame emission, and the composition of the metal in a Thomas converter in order to determine automatically the metallurgical state in the melt. In a recent U. S. Patent (NO. 2,831,762)' issued to two Austrian inventors, Kemmetmuller and Rinesch, the inventors claim a process for treating the exhaust gases from a converter. By their method the inventors claim that the exhaust gases from the converter are cooled immediately after leaving the converter to a degree that oxidation of the metal vapors and metal particles to form Fe2O3 is inhibited in the presence of surplus oxygen. Gledhill, Carnall, and sargent7 report on cleaning the gases from oxygen lancing of pig iron in the ladle. They claim the Pease-Anthony Venturi scrubber removed 99.5 + pct of the smoke, thereby reducing the concentration to 0.1 to 0.2 grain per cu ft, which resulted in a colorless stack gas after the evaporation of water. Fischer and wahlster8 developed a small basic converter and compared the metallurgical behavior of the blow with that of a large converter. Later work by Kosmider, Neuhaus, and Hardt9 on the use of steam for reduction of smoke from an oxygen-enriched converter confirmed that the cooling effect of steam is detrimental to production. From review of all of the published information on the subject, it was concluded that a practical solution to the smoke-elimination problem had not been found. Accordingly, it was deemed desirable to investigate the feasibility of preventing the initial formation of smoke in the converter.

Jan 1, 1961

By F. Wartenweiler

Much has been written on milling and cyanidation as practiced on this gold field, therefore the purpose of this paper is to record its development only briefly and to describe in more detail the contemporary state of the science and art of this branch of metallurgy. It is a pleasing task, because a steady evolution is to be recorded. Definite trends influenced the development. Some have the stamp of original thought and observation; many have been achieved from a logical sequence of planned experimentation and research; while others have resulted from the drive of sheer necessity. The large scale of operations and capital outlay has compelled conservative progress. Banket ORe For a better understanding, a review of the characteristics of the ore may not be out of place. The Witwatersrand gold ore is named "banket" from the similarity of the oxidized outcrop ore to the Boer almond cake of that name. The inter bedded orebody is commonly called "reef." It is a conglomerate composed of various sizes of pebbles, principally non-gold-bearing white quartz, which constitute about 70 per cent of the bulk, within a matrix of cementing material consisting of fine-grained quartz, sericite, chlorite and chloritoid and containing the precious metals and mineral sulfides. Argillaceous components in the mil pulp may be as high as 32 per cent. Of the sulfide minerals, pyrite and pyrrhotite are predominant. Most base-metal sulfides are present, but sporadically and generally only found in highly concentrated mill products. In the latter, osmiridium is recovered in varying amounts; from 1 oz. in 3000 tons to 1 oz. in 10,000 tons of ore. Most of the oxidized ore has been mined, so milling is confined principally to the sulfide ore. A typical analysis of sulfide ore is: silica (SiO2), 86.76 per cent; pyritc (FeS2), 2.75; ferric oxide (Fe2o3), 2.65; alumina (Al2o3), 6.91; lime (CaO), tr.; magnesia (MgO), 0.70; sp. gr., 2.7. Milling grade at present price of gold (137 shillings per ounce) varies from 3.5 to 8.5 dwt., with one mine milling ore as high as 16 dwt. The

Jan 1, 1935