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By James Aston

Three years ago the writer presented a paper on the trend of development in the wrought iron industry,' wherein was described a process in the development of which he has been a factor, which at that time had passed through several years of progressive experimental development but which had not then been put upon a commercial scale of operation. The present paper deals with two years of observation and experience in the commercial operation of a plant by the A. M. Byers Co. at Warren, Ohio. It will not enter into the controversial field of the relative merit of wrought iron and steel in various classes of service, nor will it elaborate upon the characteristic services or fields of utility to which wrought iron is particularly adapted. It is sufficient to state that the wrought iron industry is upon a substantial basis and that the material finds service in pipe, where its advantages are in superior corrosion, fatigue, welding and threading qualities; in bar iron for staybolts, engine bolts, and rivets, demanding maximum service against corrosion and fatigue; in plates for corrosion service; and in chains, because of welding and shock-resisting characteristics. In short, ability to withstand the stresses of shock and vibration, or the ravages of corrosion, to hold protective coatings, and to give maximum efficiency in welding, are its features of relative superiority. If these features were not well recognized, the wrought iron industry would have shrunk to insignificance in the face of high costs and acknowledged limitations in manufacture. To charge that this industry is built upon a structure of assumption, psychology, and improperly weighed evidence is an impeachment of the integrity or belittling of the powers of observation of users through many centuries of service experiences. In a history which extends to prehistoric time, and which is linked up with the earliest records of ferrous products, the dominant method of manufacture, as we have known it for little over a century, occupies a very small niche in the span of years that mark production and use of wrought iron. Puddling, the outstanding manufacturing method of

Jan 1, 1929

By Research Staff ? Verde Copper Mines

FLOTATION is now commonly practiced in alkaline ore pulps, yet little is known regarding the action of the alkaline solutions on the ore particles beyond the fact that films of oxidized material form. We wish to chronicle our discovery of the presence of soluble reducing agents in alkaline ore pulps of the United Verde, and present some data on lime consumption. During the grinding and flotation of a pyritic ore containing small amounts of ferrous sulfate and other soluble salts, an excess of lime was added to precipitate the salts, and filtered samples of the solution were titrated with standard permanganate solution. Even in pulps of high causticity an appreciable permanganate titration was always obtained, in spite of the fact that the solutions were shown to contain little iron. Investigation of the cause brought about the discovery of several previously unsuspected compounds in flotation pulps made from pyritic ore. Not only the reducing agents present had to be identified, but also the amount of dissolved oxygen, and a survey was finally made of the free oxygen content and reducing agents of the mill pulp in the concentrating mill at Clarkdale. A great many compounds might form, caused by oxidation of pyrite or other metal sulfides or by reaction between a lime solution and pyrite. The most probable compounds considered were calcium sulfides; polysul-fides, thiosulfates, and polythionates. Later it was discovered in the literature that in alkaline pulp polythionates do not exist and if introduced. are decomposed into sulfites and thiosulfates.1 Any precipitated sulfur is changed by alkali into thiosulfate and polysulfide. Sulfites and sulfides react to form thiosulfate, so that in the end it is possible to have in an alkaline solution only thiosulfate and an excess either of sulfide or sulfite. Confirmatory tests were made and it was finally established that the alkaline mill pulps made from the United Verde ore contained

Jan 1, 1929

By COURTNEY DE KALB

IRON ore is the cause of the present trouble in Morocco. At least three nations are interested in the outcome and private syndicates have been active. The iron deposits are found in that mountainous northern coast line known as the Rif. This is an uplift that has been cut through, by the northward drainage, representing an ancient land surface. Erosion has produced .a fiordlike coast, which circum- stance has aided contraband' traffic to the tribes dominated by Abd-el-Krim, the chief of the clan of the Beni Urriaguel, near the center of 'the north coast, opposite Alhucemas. The iron deposits are extensive in the territory of the Beni Urriaguel. They were "located," if such a term is permissible, many years ago. The first arrangements, through direct contracts with the tribal chieftains, have been reinforced by compliance with the subsequent code under the Spanish protectorate in 1914. Under those terms, the location had to be made through the Arbitral Commission sitting in Paris. These locations, or "denouncements," were made by the I-louse of Mannesmann, of Hamburg.

Jan 1, 1925

By I. F. Jackson, H. L. Hartman

Hard-metal inserts have received considerable attention in the mining industry recently for a variety of excavating and penetrating purposes. Their use in percussive drilling and in coal cutting machines is well known, but attempts to utilize them in cutting materials such as dimension stone have been discouraging because of excessive tool wear and failure. Particular attention is given to those properties of hard-metal inserts that affect their resistance to wear. A consideration of the actual wear mechanism shows the importance of correct mounting of the inserts and of the selection of suitably powered driving motor so as to achieve minimum tool wear and maximum tool life. Comparisons are made between the performances of types of hard-metal inserts, relating their inherent properties with results obtained in laboratory tests. As part of a broad program to improve the quarrying and processing of industrial minerals, The Pennsylvania State University has been investigating the machinability of slate under laboratory and field conditions. It should be emphasized that the results of the research presented in this paper are also applicable to other natural structural materials, and particularly to the more workable ones such as limestone and sandstone. Improvements which accrue in cutting and sawing should prove of benefit to all the dimension stone industry. Further, it may be pointed out that the results reported here are applicable to rotary drilling (with drag bits) as well as to cutting and sawing of rock. INVESTIGATIONS IN RELATED FIELDS The investigation was initiated with an extensive survey of available literature related to metal cutting and to rotary drilling. The following similar features between metal cutting and slate cutting became evident: 1) Hard-metal inserts are widely used as a cutting tool in both cases. 2) The forces acting on the tool may be resolved into normal and tangential components. 3) Rate of penetration and tool wear are important criteria in each case. On the other hand, important differences also exist: 1) Most metals, exhibit plastic behavior, while slate (and most rock) is a brittle material under normal conditions. 2) In metal cutting the component of force acting parallel to the surface of the workpiece is considerably greater than the force holding the tool against the workpiece. 111 slate cutting, this situation is reversed. Similarities between drag-bit rotary drilling and slate cutting are as follows: 1) In both casts, a tool, usually of the hard-metal insert type, is used to penetrate a brittle material. 2) The drilling forces and related variables, such as rotation speed, are similar. 3) Chip formation in each case is essentially the same. 4) The shape of the tool is similar in rotary drilling and slate cutting. Important differences are also apparent: 1) The objective of drilling is to produce a directed hole, while in cutting it is to form a kerf. In core drilling, however, a kerf is also produced. 2) The horizonta1 component of force in rotary drilling decreases from the center to the outside of the tool, whereas in slate cutting the component is almost uniformly distributed across the width of the tool. 3) The power absorbed in the drill rod is greater in rotary drilling. 4) The clogging action of chips, if excessive power is applied to the tool and if flushing is insufficient, is more serious in rotary drilling. Because of the striking similarities between metal cutting and slate cutting, and between rotary drilling and slate cutting, it was considered that the findings of investigators in those fields would serve as a guide for experimental studies of slate cutting. The following is thus devoted to a discussion of those aspects of metal cutting and rotary drilling pertinent to the present investigations.

Jan 1, 1962

By William Kranz

Discussion of the paper of WILLIAM G. KRANZ, presented at the San Francisco meeting, September, 1915, and at the New York meeting, February, 1916, and printed in Bulletin No. 101, May, 1915, pp. 927 to 930. J. W. RICHARDS, So. Bethlehem, Pa.-At the present time I believe there are 35 electric steel furnaces under construction in the United States, and many more in operation. The United States Steel Corporation, for example, is putting up for one firm a plant of eight electric furnaces. The principal increase in use of the electric furnace at the present time is based on its superiority for making steel for shrapnel and for munitions of war. I understand that electric steel has been found far more reliable and suitable than ordinary steel for these purposes in Europe.

Jan 5, 1916

By K. Kobayashi, K. Ueda, K. Yamaguchi

Lead concentrates from Kuroko (black ore) mines, which contain 4-7% Cu, 55% Pb, 3-777, Zn, and 0.5-0.9% As, are pretreated by a hydrometallurgical process before electric furnace smelting with other lead resources from Kuroko. The hydrometallurgical pretreatment involves sulfuric acid leaching in the first stage and ferric leaching in the second stage. This paper describes the short history of lead recovery from Kuroko and the performance of laboratory tests and pilot plant and commercial operations.

Jan 1, 1985

By S. Korman, S. B. Tuwiner

THE purpose of this study is to investigate the effect of agitation upon the flotation of chal-cocite. It is believed that the concentration of collector which is required to produce a water-repellent surface upon the mineral is determined among other things by the rate of collector diffusion through an impeding film of more or less stagnant fluid. Its thickness depends upon the intensity of agitation. In the first part of this study a method is developed for determining the thickness of the fluid film upon a polished surface of synthetic chalcocite. The film thickness is then determined as precisely as possible under three readily reproducible condi-tions of agitation intensity. These determinations serve as a quantitative evaluation of agitation. In Part 2 it is demonstrated that in solutions of lime at PH 10.5 and in the absence of air or dissolved oxygen the concentration of collector required to develop water-repellency upon the surface in any given time is a function of the fluid film thickness, and that after about 10 min the relation becomes linear. This points to the possibility that the collector ions may be involved in a diffusional process through the fluid film. In Part 3 it is shown that where air is present more collector is required to produce water-repellency than for the case in which air is excluded. Next, it is shown that for the latter case the most minute amount of sodium sulphide suffices to preclude development of water-repellency. Both oxygen and sulphide are in a sense, therefore, depres- sants for chalcocite in a lime solution at PH 10.5. When oxygen and sulphide are present simultaneously there is a region of minimum critical collector concentration for water-repellency which is very markedly lower than the concentration where oxygen alone or where sulphide alone is present. Moreover, this minimum appears to be identical with the collector concentration which is required where sulphide and oxygen are both excluded. This would appear to indicate that in certain ranges of concentration of oxygen and sulphide, each cancels the effect of the other. The range of concentration of solution for this effect in solutions saturated with oxygen is a function of the agitation intensity. Thus we are led to believe that a chemical reaction involving sulphide and oxygen occurs at the surface of the chalcocite. Part 4 of this study is a further development of this idea and some of its consequences from an electrochemical standpoint, while in Part 5 the disappearance of sulphide from pulps of several minerals is noted with an indication that both dissolved oxygen and the mineral are necessary, the reaction being catalytic or pseudocatalytic. Part 1. Determination of Fluid Film Thickness The Fluid Film Concept: The hindrance to the diffusion of collector to the surface of the chalcocite is a barrier of stagnant fluid in the vicinity of the surface. It is the same barrier that limits the rate of transfer of heat, the rate of solution of dissolving crystals, or any of the other rates pertaining to chemical engineering unit operations in which the film resistance to diffusion plays a principal role.' Fluid films are present upon the surface to an extent which varies with the geometry and intensity of agitation. They result from the fact that in the region within the fluid near a surface, motion is entirely parallel to it. From the standpoint of transfer to or away from the interface the effect is as though the fluid were stagnant. Outside of the film, movement of the fluid may be streamline or turbu-

Jan 1, 1951

By S. Korman, S. B. Tuwiner

THE purpose of this study is to investigate the effect of agitation upon the flotation of chal-cocite. It is believed that the concentration of collector which is required to produce a water-repellent surface upon the mineral is determined among other things by the rate of collector diffusion through an impeding film of more or less stagnant fluid. Its thickness depends upon the intensity of agitation. In the first part of this study a method is developed for determining the thickness of the fluid film upon a polished surface of synthetic chalcocite. The film thickness is then determined as precisely as possible under three readily reproducible condi-tions of agitation intensity. These determinations serve as a quantitative evaluation of agitation. In Part 2 it is demonstrated that in solutions of lime at PH 10.5 and in the absence of air or dissolved oxygen the concentration of collector required to develop water-repellency upon the surface in any given time is a function of the fluid film thickness, and that after about 10 min the relation becomes linear. This points to the possibility that the collector ions may be involved in a diffusional process through the fluid film. In Part 3 it is shown that where air is present more collector is required to produce water-repellency than for the case in which air is excluded. Next, it is shown that for the latter case the most minute amount of sodium sulphide suffices to preclude development of water-repellency. Both oxygen and sulphide are in a sense, therefore, depres- sants for chalcocite in a lime solution at PH 10.5. When oxygen and sulphide are present simultaneously there is a region of minimum critical collector concentration for water-repellency which is very markedly lower than the concentration where oxygen alone or where sulphide alone is present. Moreover, this minimum appears to be identical with the collector concentration which is required where sulphide and oxygen are both excluded. This would appear to indicate that in certain ranges of concentration of oxygen and sulphide, each cancels the effect of the other. The range of concentration of solution for this effect in solutions saturated with oxygen is a function of the agitation intensity. Thus we are led to believe that a chemical reaction involving sulphide and oxygen occurs at the surface of the chalcocite. Part 4 of this study is a further development of this idea and some of its consequences from an electrochemical standpoint, while in Part 5 the disappearance of sulphide from pulps of several minerals is noted with an indication that both dissolved oxygen and the mineral are necessary, the reaction being catalytic or pseudocatalytic. Part 1. Determination of Fluid Film Thickness The Fluid Film Concept: The hindrance to the diffusion of collector to the surface of the chalcocite is a barrier of stagnant fluid in the vicinity of the surface. It is the same barrier that limits the rate of transfer of heat, the rate of solution of dissolving crystals, or any of the other rates pertaining to chemical engineering unit operations in which the film resistance to diffusion plays a principal role.' Fluid films are present upon the surface to an extent which varies with the geometry and intensity of agitation. They result from the fact that in the region within the fluid near a surface, motion is entirely parallel to it. From the standpoint of transfer to or away from the interface the effect is as though the fluid were stagnant. Outside of the film, movement of the fluid may be streamline or turbu-

Jan 1, 1951

By W. V. Youdelis, W. H. Bear, G. Cochrane

HERETOFORE, there has been very little study of the effects of various metallurgical factors on the behavior of thermoelectric materials, the need for which is evident if optimum processing and design of thermoelectric devices is to be realized. Accordingly, we have undertaken such an investigation on the thermoelectric materials bismuth and Bi-Sb alloy and in this paper present some preliminary results which merit consideration, in particular the relatively high thermoelectric power and figure of merit values obtained for the Bi-12Sb (at. pct) alloy powder compacts. The thermoelectric parameters for ingot and powder compact specimens are determined and the results are compared with published data for single crystals. Preparation of Materials. The bismuth and antimony used in this investigation are six nines pure. Melting and casting of the ingots was carried out in air for expediency, since most oxidation unavoidably occurs during the preparation of the powder by filing of the ingots. Chill cast ingots of pure bismuth were prepared by pouring the melt into split copper chill molds, and unidirectionally solidified ingots of bismuth and Bi-Sb alloy were obtained by slow directional cooling in pyrex tubes. All melts remained bright during melting and casting, indicating minimum oxidation. Powder for the powder compact samples was obtained by filing the ingots with a fine and coarse file to give a variation in the particle size of the compacts. The particles in the fine powder compacts varied in size from approximately 28 pct less than

Jan 1, 1970

By Forrest K. Pence

Bentonite deposits are known to occur in Texas within the Jackson group of formations. This group represents the uppermost Eocene age sediments found in the coastal plain area of Texas. It outcrops across this area of the state in a narrow band of some 4 to 20 miles width. The outcrop pattern roughly parallels the present Gulf of Mexico shore line and is some 100 miles inland from the Texas shore, Fig 1. The principal bentonite deposits are found in the areas where this outcrop pattern cuts across the south-central Texas counties of Karnes, Gonzales, and Fayette. In these deposits, the better quality bentonite is found in the lower or bottom layers of the volcanic ash deposits in which they occur. Some of these better quality benton-ite~ develop very light colors upon firing and therefore justify their being classified as "white firing." The deposits in Karnes and Gonzales Counties apparently occur in commercial quantity, whereas the white firing strata so far uncovered in Fayette County have been too thin to be classified as yet as "commercial." A study of the ceramic properties of the weathered ash in Gonzales and Karnes Counties was reported in 1941.' Commercial development of the deposit in Gonzales County, 7 miles east of Gonzales, Texas. was started earlier by the Max B. Miller Co. for the purpose of marketing the material as a bleaching clay, and this operation has developed to very sizable proportions. In recent years, this company has offered a specially selected grade of the Gonzales material as a suspending agent in glaze slips. The white firing property especially adapts the material to use in white cover coat enamels. The strata in the deposit are practically horizontal and consist from top to bottom of approximately 2 ft of soil overburden, 10 ft of brown bentonite, 2 ft of coarse white bentonite, and 4 ft of waxy white bentonite overlying a he grained sandstone. The & being made in the quarry is approximately one-half mile in length. Only the bottom 4 ft of waxy bentonite is being recovered, the upper layers being stripped and wasted, Fig 2. It may appear somewhat surprising that the very bottom strata appears to have been the one most completely altered. To confirm this, samples from top to bottom of the various strata were studied microscopically by R. F. Shurtz. Professor of Ceramic Engineering, University of Texas. His interpretation is to the effect that the lower part of the seam was deposited at a much earlier date than the top, and that the lower part was chemically altered to a considerable extent before the upper part of the seam was laid down. The conclusion to be derived from these examinations may be stated briefly to he that the alteration in these strata or parts of strata has proceeded independently of the alteration in other parts of the strata during a considerable geological period. The presence of gypsum and iron stain throughout all of the strata indicates that alteration is now proceeding more or less uniformly throughout. It is contended that the alteration of the original ash to montmorillonite is not a result of the presently operating processes. A deposit which occurs approximately 7 miles southeast of Falls City and just south of the village of Casta-howa, has been explored and leased by J. R. Martin, of San Antonio. Mr. Martin has conducted mining and marketing operations in bentonite for a period of many years and asserts that the white firing strata found in this deposit occurs in commercial quantities. His pit, which is shown in Fig 3, exposes 2 ft of soil overburden, approximately 5 ft of white bentonite having coarse texture, and approximately 5 ft of waxy white bentonite which in turn overlies a brown sandy clay. Here, as in the Gonzales deposit, the most completely altered portion is found at the bottom of the seam, as per following report of microscopic examination by Mr. Shurtz. Sample No. 1: This sample was taken from the top stratum which is one foot thick. It is grayish in color and it contains visible fossilized plants. The color is probably the result of fine carbonaceous material in the rock. Under the microscope the sample is seen to consist of glass and feldspar; the amount of glass predominating. Both these substances are slightly altered. No montmorillonite or other clay mineral can be identified definitely; however, the products of the slight alteration mentioned are probably montmorillonite or mineral gel. Sample No. 2: This sample was taken from the stratum second from the top. This stratum is fourteen inches thick. The sample is light gray. It shows numerous veinlets of greenish translucent material ranging from one-eighth inches wide down to the limit of visibility with the unaided eye. It has the smooth, sub-conchoidal fracture characteristic of some bentonites. Microscopically the sample consists mainly of aggregates of clay minerals. The birefringence of the aggregates is lower than would be expected if the

Jan 1, 1950

By AIME AIME

THE following compilation of State bureaus and officials that deal with mineral resources is compiled in part from a new "Check List of State Agencies and Officials Concerned with the Management of Natural Re- sources," compiled for the National Resources Committee, Washington, D. C., by Clifford J. Hynning. Alabama-Geological Survey of Alabama, University. Walter B. Jones, State Geologist. Chief Mine Inspector: W. B. Hill- house, 614 Lincoln Life Bldg., Birmingham.

Jan 1, 1939

By Fred McConnell

FROM beginning to end, the processes of coal stripping are of great interest. From the time the prospector enters upon the property to examine it and to prove it, until the coal is loaded into railroad cars, every step must be taken with careful thought and planning. In proving the merits of a prospective property, an examination and computation of the overburden is of almost equal importance to the determination of the extent and quality of the coal bed itself. Is the overburden hard, and will it require drilling and shooting? How many yards of it will have to be handled to produce a ton of coal? Will it remain in place when .put in the spoil bank, or will it spread and run back into the pit? Are the drainage problems serious, and what will it cost to handle the water? Does the coal have bad dips, and what will be the grades and curvatures for haulage? These are a few of the physical problems that confront the prospector, and they can be ascertained only by adequate and careful drilling and engineering of the property to be considered. The engineer is an ever-present necessity, not only in the prospecting but in the daily operation of the property after it has' been approved and developed. The first step in operation after the location of the tipple is the contouring of the surface to be stripped and the laying out of the pits for operation, having in view again adequate room for spoil, drainage, haulage and other problems. If the overburden is hard, as much of it is in the larger stripping areas, it must be drilled for shooting with churn or well drills, the holes continuing from the surface down to or near the coal bed. The location of these holes should be made, and marked with stakes, by the engineer, acting in conjunction with the shooting foreman. The usual practice is to drill holes 6 in. in diameter, although the present tendency is to increase the diameter of these holes so that they will hold, without springing, a larger charge of explosive. With the use of the old method of shooting, the holes were sprung or chambered several times with charges of dynamite, and in the cavity thus made, the explosive was placed, largely at the bottom of the hole; but with the use of liquid oxygen as an explosive, and with the later

Jan 1, 1931

By D. J. DeLazaro, W. Rostoker, R. E. Riley, M. Hansen

KNOWLEDGE of the isothermal transformation behavior and the TTT chart method of graphically summarizing such information has been of invaluable aid to the ferrous metallurgist in understanding and developing heat treatments intended to provide specific mechanical properties. It is to be expected that similar lines of study directed to titanium-base alloys will be as profitable. This paper summarizes, on conventional TTT charts, the isothermal transformation products and pertinent reaction rate data for binary alloys of titanium containing 1, 3, 5, 7, 9, and 11 pct Mo, respectively. The results so presented were derived from metal-lographic examination. Some X-ray diffraction work was done to clarify certain points of question. Ti-Mo System To the authors' k.nowledge, TTT charts have only been used to describe the reaction rates of eutectoidal decompositions. It would seem that the kinetics of decomposition of any unstable solid solution might be conveniently described in this manner. The equilibrium diagram of the Ti-Mo system' is shown in Fig. 1. The similarity with the Fe-Ni system will be recognized. Additions of molybdenum serve to stabilize the /3 phase to increasingly lower temperatures. The solubility of molybdenum in the a phase is restricted to less than 1 pct at 600°C. Under normal conditions. a homogeneous ,8 structure quenched to a, temperature in the a f & field will reject a of invariant composition. The rate at which this occurs depends on the degree of undercooling and the degree of supersaturation of /3. The structural character of the rejected phase may also be expected to be related to the undercooling. Materials and Experimental Methods A sponge titanium was used which has a nominal impurity content as reported in Table I. The nominal composition of the molybdenum used is also included. The alloys were prepared in 150 g melts by arc melting in an evacuated water-cooled copper crucible of the type reported in an earlier paper.' The pancake-type ingots were forged to 1/4x1/4 in. bars and homogenized for 24 hr at 1000°C in evacuated Vycor bulbs. Specimens Vi in. thick were cut from these bars for heat treatment. The heat treatment cycles followed an invariant procedure. The specimens were soaked at 1000°C for 20 min under a helium protective atmosphere prior to quenching into a lead bath held at a temperature corresponding to a chosen degree of undercooling. After a prescribed period of time at this temperature, the specimen was removed and water quenched. A series of specimens so treated for progressively longer periods served to establish the times for initiation and completion of the decomposition of the /3 phase at a particular temperature. Although heat treatment of unprotected specimens in a lead bath does permit surface contamination by lead diffusion, this method is necessary to insure sufficiently rapid quenching rates. As long as the bath treatments were of less than 1 hr duration. the contaminated surface was not unduly deep and could be removed without excessive grinding. Metal-lographically, the contaminated zone could be readily distinguished from the pure binary alloy. Transformation Characteristics of Ti-Mo Alloys Metallographic examination showed that a supersaturated p phase may decompose by one of two processes. Alloys containing 1 to 9 pct Mo, when quenched in water from the homogeneous /3 field,

Jan 1, 1953

By D. U. Deere, F. D. Patton

Introduction A close relationship exists between the geologic investigation and the stability analysis of the slopes of an open pit mine. One significant result of this relationship is that the stability analysis is no better than the assessment of pertinent geologic factors that enter into the analysis. In some slope stability problems the engineering solution becomes obvious once the geologic framework is established. In other cases, establishing the geologic framework is only the first stage in the process of analysis. However, even in these cases the geology should not be neglected once the analysis is made. The geology should be periodically reviewed when new slopes are excavated. This will help ensure that the basic assumptions for the analysis have not changed and will permit changes when new conditions are encountered. In recent years improved methods of stability analysis have been accompanied by advances in laboratory testing techniques and new knowledge of the shear strength of rock discontinuities. At the same time there have been improvements in field geological descriptions. As more experience is gained in analyzing and predicting the stability of rock slopes, the importance of certain geologic factors has become more apparent. Some of these factors were described in a paper given at the Open Pit Mining Symposium in Johannesburg, South Africa in September 1970 (I). This paper includes many of the points covered at that meeting but with additional emphasis on the significance of the major geologic structures. Other papers given at the South African symposium also considered geological and hydrogeological factors in slope stability analysis (2) (3) (4) (5) (6). This paper first describes the approach to a slope stability problem including assessment of the relative roles of field geology studies, laboratory testing, stability analyses, and continued slope monitoring studies. Next, is described a framework which has been found useful for classifying or separating the several types of slope stability problems encountered in open pit mines. The principal geologic factors in slope stability problems in rock are discussed and brief comments are made on how these factors distinguish stability problems in rock slopes from those normally encountered in soil slopes. The over-riding control of major geologic structures, especially faults, in most slope stability problems is emphasized. In this regard the relative importance of statistical studies is contrasted with knowledge of the positions of key structural

Jan 1, 1971

By John F. Blandy

ALTHOUGH the question of the "waste of anthracite coal mining" has been so frequently discussed, and a committee was appointed at the first meeting of this Society to consider and report upon the subject, still but little progress seems to have been made in arriving at a conclusion as to how it can be reduced. That committee made a preliminary report at the August meeting, 1871, in which it divided the question into three parts, namely Waste in mining, in preparing for market, and in transportation. I shall not here refer to the first item, as so much depends upon the peculiar features of each separate mine, and the skill of those in charge; but in reference to the second, that of preparing the coal for market in breaker and screens, I wish to make some remarks. There is no use considering the question, whether the coal should be broken up to suit the fancy of consumers; all miners are satisfied that it should not be, but the consumers decide that they want it that way, and the miner must submit, and simply utter his maledictions upon the head of the man who first suggested a breaker or screen, if that is any consolation to him. What is called waste in this process of preparation, is the dust and fine coal, which results from the breaking and screening, and, as we all know, this is a very important percentage of what passes from the slope to the top of the breaker. Now, if this dust and fine coal can be utilized-the slate which is' picked out is not to be taken into consideration as waste-then we get rid of this item entirely. There is no question in my mind that this article can and will be used as a steam generator at least, and I think, therefore, that in depositing

Jan 1, 1877

By L. A. Rapoport

This paper is intended as an aid in the perfornzance and interpretation of experimental studies of multi-phase flow in porous tnedia. The mathenmatical formulation of incompressible, two-phase flow phenomena in a three-dimensional porous medium is presented. The resulting equations which account for the effects of gravitational and capillary forces are used to derive general scaling laws permitting accurate representation of water-oil displacement processes by means of experimental flow models. The significance of the scaling laws is examined in the light of the physical concepts of micro-behavior of fluids in porous media. Formulations of scaling con(litions obtained by application of dimensional analysis are reviewed. The principles of application and the limitations of flow model studies are discussed. INTRODUCTION Most of the problems facing a reservoir engineer involve three-dimensional, two-phase flow systems. influenced by the effects of gravitational and capillary forces. Present computational procedures generally do not permit the evaluation of such systems without introducing greatly simplifying assumptions. The actual reservoir configuration is usually replaced by one or a combination of several "equivalent" linear systems, and the effects of capillarity and gravity are considered to be negligible. While these assumptions may in many instances be justified, there are a number of important practical problems for which the results obtained on the basis of such simplifications remain open to question. An alternate approach to the problems that are not amenable to analytical treatment consists of seeking their solution by experimental laboratory investigations. The main difficulty of such investigations lies in the fact that multiphase flow phenomena subjected to gravity and capillary forces proceed differently at different rates and in systems of different dimensions. Therefore, unless great discrimination is exercised in selecting the conditions and interpreting the results of laboratory tests, such tests may be entirely misleading in regard to field applications. The purpose of this paper is to present a theoretical background for the performance of laboratory tests that are more nearly representative of field behavior. It will be shown that simulation of field behavior can be achieved by conducting laboratory tests under conditions selected in accordance with definite scaling laws. The formulation of conditions required for the scaling of two-phase flow experiments in porous media has been presented in the literature on several occasions.12,3,4 One of these formulations advanced by Leverett1, cannot be considered applicable to most practical cases inasmuch as it does not cover generally the regime of laminar flow. An adequate treatment, based on the consideration of dimensional analysis, was presented by Engelberts and Klinkenberg.2 Their treatment, however, is concerned primarily with the scaling of linear flow systems, and hence somewhat limited in scope. Accordingly, the formulation of more general scaling laws, applicable to three-dimensional systems, appeared to be warranted. It appeared, furthermore. desirable to establish this formulation on the basis of a mathematical treatment, rather than by application of general principles of dimensional analysis, to permit more explicit

Jan 1, 1956

By H. S. Ten Eyck

Fertilizer normally is spoken of as having three main components: nitrogen, phosphorus and pot- ash. Certainly, however sulfur must also be considered a basic component of fertilizers, even though in many instances it does not end up as a part of the end product. In addition, with heavier cropping and the resultant drain of plant foods from the soil, we have now reached a point where the minor elements necessary for plant growth have become a major factor in the fertilizer industry.

Jan 7, 1967

By Henry D. Hibbard

A noted ordnance engineer once said to a friend, in speaking of the production of great steel guns, " How is it ? We design our guns with a factor of safety of eight, and the guns burst." The vague way in which internal stresses and strains in iron and steel are often considered and spoken of makes it worth while to examine them, as to their nature, their causes and results, how they may, for useful purposes, be advantageously dealt with, and how, when detrimental or dangerous, they may be reduced or kept within harmless proportions. Rankine defines " strain " as a change of form or dimensions of a solid or liquid mass produced by a stress. This definition seems intended not to cover strains due to internal stresses, and it will help us in the present inquiry to consider strain as a tendency to change as well as an actual change of form. Internal strains in iron and steel are the result of stresses within the mass of the piece, some parts pulling and others pushing in resistance to them; or, in other words, some parts are in tension and some in compression, each part striving to relieve itself from strain and make the piece assume a form in which all parts are at rest. Subdivision, so that each part could relieve its strain by motion relative to the other parts, would, if carried out far enough, practically obliterate strain. The internal strains we are now to consider are not those due to the stresses of the service which the piece is rendering, either alone or as a part of a structure, which may be termed service-strains, but those which originate or at least are contained in the piece itself. Internal stresses in a piece of metal are, like action and reaction, always equal and in opposite directions. The stresses

Jan 1, 1907

By A. D. Rovig, D. W. McGlashan, Donald M. Podobnik

Crystal-chemical and stntctural properties of sulfide minerals are considered. The information gained is to be used to interpret (I ) freshly broken mineral surfaces, (2) modifications of the mineral surfaces, and (3) reactions at the mineral surfaces. From these basic disciplines, concepts with regard to the changes that surfaces undergo, reactions that might take place, the geometry of the interface, the state of different atoms and ions in the interface, and other physical and chemical properties of an interface must be developed, weighed and applied. The authors first deal with these conceptual considerations from which hypotheses are set forth to describe the environ men tal-interfacial relationships for several sulfide minerals. Qualitative and quantitative explanation of par-ticulate solid separations are unknown entities because of the lack of adequate models and mathematical relationships to explain the activity occurring between the solid and liquid phases. It is a transitional region in which it is difficult to ascertain the mechanisms of adsorption of ions, molecules, etc., on mineral surfaces, as well as other secondary reactions which occur in interfacial regions. Thus, in this paper the authors deal with conceptual considerations from which hypotheses are set forth to describe the environmental-interfacial relationships for sulfide minerals. GENERAL CONSIDERATIONS Interfacial Reactions:Interfacial reactions are the cruxes of flotation schemes as well as other processes such as thickening, filtration and hydrometallurgy. However, as noted by Klassen and Mokrousov: 1 "The problems concerning the surfaces of natural minerals, the laws governing simultaneous adsorption from aqueous solution on these surfaces of a whole series of reagents, the laws of the surface reactions and the properties of water layers separating the minerals, are all known to a first approximation only." An investigator has the privilege of postulating methods of solid-liquid interfacial reactions. REACTIONS WITH WATER - Water consists of hydronium (H3 O 4) and hydroxyl (OH-) ions in the ionized state. That this is so forms the basis for the postulated reaction of the hydrated hydrogen ion with net-negative mineral surfaces as depicted in Fig. 1. In this case water is bonded to mineral surfaces through hydrogen-bridge-type bonds - possibly hydrogen bonds. Although bonding of the van der Waal type may be responsible for this reaction, it is most likely that stronger bonds are involved. Once firmly bonded to the surface, the water layer is known to be quite tenacious. It is further speculated that a shear plane exists at some distance (see Fig. 1) away from the mineral surface. Exact location of this plane is not known, but in all probability it will be positioned across a weak bond of the hydrogen-bond type where the surface-attached water is coordinated to the original hydrated hydrogen ion. REACTION WITH METAL IONS - Klassen and Mokrousov ' state: "The presence of an ion in water leads to an immediate formation around that ion of a highly condensed atmosphere of water dipoles and thus to hydration of the ion." The fact is known that multivalent cations are strongly hydrated, usually by six or eight molecules of water, and that anions are not so strongly hydrated. Conceding the fact that thermodynamics, concentration, pH, and physical considerations are of utmost importance in truly explaining a mechanism of metal ions reaction with a hydrated mineral surface, it does seem logical that the mechanism illustrated in Fig. 2 is feasible. In this reaction, the metal ion (M) is coordinated in one dimension - to the mineral-surface hydration layer. Note also that explanation of this reaction requires that the shear plane move to a less stable bond configuration; that is, the shear plane has moved to a position between the metal ion and the other coordinated water molecules which are more free to dissociate. Reactions as depicted in Fig. 2 should cause the formation of an apparent mineral surface which is net-positive. Immediately, it must be noted that measurements of apparent-mineral surfaces serve - within limits - to indicate a degree of ion-surface reaction capability. The major limiting factor he re is one related

Jan 1, 1970

By J. B. Newkirk, D. L. Martin, A. H. Geisler, R. Smoluchowski

A FUNDAMENTAL investigation of the mecha-nism of the ordering reaction and of the accompanying changes in properties has been undertaken, since an extensive study of this process could well contribute to the knowledge of phase transitions in alloys. Cobalt-platinum alloys were chosen for the study since they exhibit interesting and unusual permanent magnet properties.1,2. In addition, the ordering reaction in cobalt-platinum alloys is a convenient one to study experimentally because of the high maximum ordering temperature, the large difference in the X-ray scattering power of cobalt and platinum atoms, and the relative ease with which the alloys can be plastically worked into wire and strip. In the early stages of this study, it became apparent that the published phase diagrams&apos;, &apos; of the cobalt-platinum system contained questionable features, in the region of 40 to 60 atomic pct Co, which were considered in another publication by the authors.4 That portion of the research reported elsewhere on the equilibrium states of cobalt-platinum alloys does not confirm the presence of a previously reported, high temperature disordered tetragonal phase and a low temperature body-centered cubic phase. On the other hand, the structure of the ordered phase is face-centered tetragonal with an atomic distribution analogous to that of CuAu.4 This lattice forms from the disordered face-centered cubic phase in such an orientation that the <100> directions are parallel to the <100> direc-tions of the disordered phase. At compositions other than the ideal 50 atomic pct the ordered phase can exist in equilibrium at high temperatures with the disordered phase. A Widmanstatten pattern of plate-like particles of the ordered phase parallel to (110) planes of the disordered matrix is observed when an initially disordered alloy is held at these temperatures. The temperature range of the two-phase region has been determined for three alloys by X-ray diffraction analyses, microscopic examination, and electrical resistivity measurements, and these results are incorporated with some of those of Gebhardt and Köster in the revised phase diagram of fig. 1. The purpose of the investigation reported here was to examine the mechanism of ordering in co-balt-platinum alloys by X-ray diffraction and metal-

Jan 1, 1951