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By Calvin Pierson, R. S. Dean, E. P. Barrett

Wrought iron and steel have been prepared from limonite, hematite, and magnetite ores by gaseous reduction, compacting and squeezing the resulting product at high temperature and finally melting the wrought iron so formed. The structure, analyses, mechanical and magnetic properties of the products are given. It is found that the structure of iron ores is best studied by subjecting them to gaseous reduction and using metallographic technique on the resulting sponge iron. In this way the cell structure of iron ore is clearly shown. The wrought iron made by heating compacted sponge iron to 1450" C., and forging, shows a cell structure inherited from the ore. This cell structure is further preserved in melting and casting the wrought iron. The probable relation of the properties of the materials to this inherited cell structure is discussed.

Jan 1, 1935

By Calvin Pierson, R. S. Dean, E. P. Barrett

Wrought iron and steel have been prepared from limonite, hematite, and magnetite ores by gaseous reduction, compacting and squeezing the resulting product at high temperature and finally melting the wrought iron so formed. The structure, analyses, mechanical and magnetic properties of the products are given. It is found that the structure of iron ores is best studied by subjecting them to gaseous reduction and using metallographic technique on the resulting sponge iron. In this way the cell structure of iron ore is clearly shown. The wrought iron made by heating compacted sponge iron to 1450" C., and forging, shows a cell structure inherited from the ore. This cell structure is further preserved in melting and casting the wrought iron. The probable relation of the properties of the materials to this inherited cell structure is discussed.

Jan 1, 1935

By J. E. Lawver

On the basis of both laboratory and pilot-scale tests, a newly developed high-tension electrostatic process is technically and economically feasible for the production of iron ore superconcentrates containing 0.02 to 0.20% silica at iron recoveries of 85 to 90%. The process can be used to recover both a superconcentrate and a pellet-grade concentrate, from a feed containing middlings, and the system is not unduly upset from changes in feed structure and composition. The adverse affect of excess quantities of material finer than 30 microns, i.e., above 10% in quantity can be avoided by a desliming step. Finally, because of the cost of drying, the best feed for the process appears to be dry-ground ores as well as spiral, flotation, or magnetic concentrates.

Jan 1, 1970

By Jack F. Havard, John S. Lagarias

When ore bodies are faulted or mill feed turns refractory, mining managers and engineers act vigorously to convert imminent failure into eventual success. The recent proliferation of onerous environmental regulations and restraints is likewise a threat to successful mining enterprise, in some ways more insidious and dangerous than the problems presented by natural obstacles. The regulatory burden has become so heavy that a pall of pessimism covers much of the mining industry. In this paper we frankly recommend an approach that does not just "make the best of it" but rather directs the whole environmental process: first, to improve planning, engineering, and operating procedures; and, second, to demonstrate the need for modification of laws and regulations which are intolerably burdensome to both the mining industry and the public.

Jan 1, 1979

By E. W. Codington

The pebble-phosphates of Florida occur in a district roughly bounded on the north by the 28th parallel, on the east by an irregular line running a few miles east of Peace river and on the west by the Gulf of Mexico, and covering an area of about 4000 square miles. There seems to be no reason why the deposits should not extend farther south along the gulf coast. That section remains unprospected, transportation-facilities being non-existent. It is not intended in this paper to discuss the geology of these formations; but a word as to their probable origin will be perhaps the best method of giving a correct idea of their present position. Starting with a low, flat surface, with even less of superficial undulation than appears at present, an im-

Jan 1, 1896

By Nicholas M. Short

Many a geologist or driller has wished he could somehow climb into a borehole to see for himself what fractures looked like. Or why recovery was poor. Or how the bit was actually lost. Now it is possible to do the next best thing to climbing into the hole. TV cameras are being used for a close-up look at borehole conditions. Ever since television was invented, geologists and others interested in subsurface conditions have wanted a TV camera that could be used in the narrow confines of a borehole. But development of such a camera was slow, mainly because of the need for compact size. Not until the late 1950's did the technology of electronic miniaturization develop to a point where a camera satisfactory for the purpose could be put together.

Jan 1, 1963

By C. A. Hansen

INTRODUCTION It has been the experience of the writer, during some. five years' work with electrolytic zinc, that the zinc cell is perhaps more- sensitive to impurities in the electrolyte than the analytical methods as yet developed for the chemical identification and determination of these impurities; but that, when proper purification methods have been applied to a given solution, the behavior of the cell is quite independent of the original sources from which the zinc sulphate has been derived. It has also appeared that the behavior of the zinc cell is the best and surest check on the correctness and thoroughness of the purification methods used, because it indicates the presence of both current impurities. and cumulative impurities derived from the leaching of the ore; it also in

Jan 3, 1918

By R. W. Raymond

THE question, what is the best proportion among weight, fall, and speed of stamps, is one which has not yet received thorough and systematic examination. In considering the economical application of stamping machinery, we meet, at the beginning, with serious difficulties in obtaining accurate data for comparison. The weight and fall of stamps vary as the shoes and dies wear out; and this may lead to a change of speed also. Moreover, defects in engines, boilers, or machinery for the transmission of power, may occasion serious losses, which cannot fairly be charged to the arrangements of the stamps proper. Again, the capacity of stamp-mills is directly dependent, in some degree, upon the nature and extent of discharge, fineness of screens, and other peculiarities of the battery. Finally, the hardness and tenacity of the rock crushed varies so much that comparisons between different localities cannot be implicitly trusted. The safest experiments are those made in the same mill, by changing first one and then another condition of working; but this is seldom possible for such conditions as weight and lift of stamps, and only within narrow limits for their speed. We may eliminate of friction, transmission, and generation of power, in the case of stamps, by measuring the power actually developed by their fall. Thus, the weight, multiplied into the fall in feet, and the number of drops per minute, gives us exactly the number of foot-pounds exerted by each stamp. Dividing by 33,000, the number of foot-pounds per minute in one-horse power, we have the horse-power per stamp, from which the effective power of the whole mill may be obtained. Dividing the amount of rock crushed daily by the effective horse-power, gives us the daily amount per horse-power ; and this is the best measure that can be obtained for the effectiveness of the stamps. A complete discussion of the subject would require us to determine the exact influence of the discharge, etc., and the exact resistance offered by different classes of rocks, for both of which points the data are wanting. Professor J. D. Hague, in the third volume of the United States Geological Exploration of the Fortieth Parallel, gives a valuable

By H. C. Otis

DURING the past year or two considerable time and money have been spent in developing equipment for tubing large-volume high-pressure oil and gas wells without loss of production. That the efforts have met with success is proved by the fact that any properly cased well, regardless of its production or regardless of its rock pressure or working pressure, can now be safely tubed with no appreciable loss of production, provided experienced crews handle the new equipment. It is conceded that a far better gas-oil ratio can be secured by flowing a well through tubing of a proper diameter-the diameter of the tubing depending, of course, upon the volume of fluid and gas and the depth of the well-than by the more usual method of installing a choke at the mouth of the well. Where possible it is becoming the practice to bring wells in through tubing, though in the majority of instances this is not feasible. In many instances it has developed, after a well has been brought in through tubing, that the tubing installed is either too large or too small for the most efficient operation or that the well had not been drilled deep enough. The equipment described in this paper, in the hands of experienced men, permits the tubing of these wells after they have been brought in, with the size of tubing then determined by actual observation to be best suited for each particular well, and with no danger of the well getting out of control, of catching fire, of drilling itself deeper, or of any loss of production. The deeper the flowing production with the consequent future higher lifting costs, the more essential it is that the size of tubing used be such as to give the best possible gas-oil ratio. The ability to bring in these deep wells through the casing and then, immediately after their completion, regardless of volume or pressure, to tube them with the size of tubing that permits the most efficient use of the gas present will doubtless save many dollars.

Jan 1, 1929

By R. W. Raymond

THE question, what is the best proportion among weight, fall, and speed of stamps, is one which has not yet received thorough and systematic examination. In considering the economical application of stamping machinery, we meet, at the beginning, with serious difficulties in obtaining accurate data for comparison. The weight and fall of stamps vary as the shoes and dies wear out; and this may lead to a change of speed also. Moreover, defects in engines, boilers, or machinery for the transmission of power, may occasion serious losses, which cannot fairly be charged to the arrangements of the stamps proper. Again, the capacity of stamp-mills is directly dependent, in some degree, upon the nature and extent of discharge, fineness of screens, and other peculiarities of the battery. Finally, the hardness and tenacity of the rock crushed varies so much that comparisons between different localities cannot be implicitly trusted. The safest experiments are those made in the same mill, by changing first one and then another condition of working; but this is seldom possible for such conditions as weight and lift of stamps, and only within narrow limits for their speed. We may eliminate questions of friction, transmission, and generation of power, in the case of stamps, by measuring the power actually developed by their fall. Thus, the weight, multiplied into the fall in feet, and the number of drops per minute, gives us exactly the number of foot-pounds exerted by each stamp. Dividing by 33,000, the number of foot-pounds per minute in one-horse power, we have the horse-power per stamp, from which the effective power of the whole mill may be obtained. Dividing the amount of rock crushed daily by the effective horse-power, gives us the daily amount per horse-power; and this is the best measure that can be obtained for the effectiveness of the stamps. A complete discussion of the subject would require us to determine the exact influence of the discharge, etc., and the exact resistance offered by different classes of rocks, for both of which points the data are wanting. Professor J. D. Hague, in the third volume of the United States Geological Exploration of the Fortieth Parallel, gives a valuable

Jan 1, 1873

By J. W. Fuller

DURING the last 20 years, experimenters have sought to utilize pulverized coal in boiler plants, but refractory and slag troubles have usually overbalanced any, gains in efficiency that were obtained. These troubles were caused largely by lack of knowledge of the proper methods of coal preparation and lack of a furnace design that would be adaptable to pulverized-coal firing. When this information was obtained the results were so much more satisfactory that within the last 5 years approximately, 80,000 boiler hp. have been installed in plants ranging from 1000 to 20,000 boiler hp. rated capacity, which are operating at an average of 174 per cent. of rating. The first commercial installation for burning pulverized coal under boilers was made at the Parsons shops of the M. K. & T. railroad in 1916. Of eight 250-hp. water-tube boilers thus fitted, six were operated continuously for 3 yr., when oil was obtained at such a low price as to warrant its use. Since then, this plant has been operating alternately on pulverized coal and oil, depending on prevailing prices. Recently gas has been discovered within 20 mi. of this plant, so that this fuel may also be used. No change in furnace design was made when changing from pulverized coal to oil or gas firing. One of the principal advantages of this method of firing is its ability to utilize, with maximum efficiency, all kinds of coal, irrespective of quality or physical characteristics. In fact, quite a number of the present pulverized-coal installations were made for the purpose of utilizing coal that could not be marketed or used in any other way. The Pacific, Coast Coal Co., at Black Diamond, Wash., formerly hand fired the boilers, using approximately 125 tons of prepared steam-size coal daily. The Black Diamond steam coal is the best quality of coal for steaming purposes mined in that section of the country, and there is a market for all that can be produced. By installing a pulverizing plant, it was possible to substitute coal of a size and quality that had no commercial value, so that 125 tons daily of the best steam coal formerly used at the mines is now marketed.

Jan 12, 1921

By Harold Price

ONE year ago, that is in January, 1923, there had not been constructed a single oil-storage tank of 55,000-bbl. or more capacity with a completely electric welded roof and bottom. Today, there are at least fifty 80,000-bbl. storage tanks completed, or nearing completion, on which both the roofs and the bottoms are electric welded. It is the purpose of this paper to describe, in a general way, the construction of these FIG. 1.-ELECTRIC-WELDED SEAMS AND RIVETS OF BOTTOM IN 55,000-BBL. TANK AT EL DORADO, KANS., SHOWING ALSO PATCH PLATE WELDED TO BOTTOM. welded roofs and bottoms, and to give their advantages over riveted construction. All of the following data and conclusions were obtained from observations made during the welding of tanks by the Welding Engineering Co. at Texas City, Tex., and Tonkawa and Burbank, Okla. As far as can be determined, the first electric welding on large tankage was completed in May, 1922. At that time the Empire Companies of Bartlesville, Okla., discovered a badly leaking bottom in a 55,000-bbl. tank at El Dorado, Kans. They had considered concreting this bottom, but because of the much smaller cost, decided to try electric welding; so a- contract was given the Welding Engineering Co. of Bartlesville, Okla. In this instance, no new sheets were added, the bottom being repaired by electric welding of all seams and rivets, Fig. 1. In some places where the original rivets were missing, the holes were filled by welding; patch plates were also added at certain badly worn spots. This tank has since been in service over a year and half, but no other

Jan 6, 1924

By R. L. Whiting, H. J. Ramey

The basic study from which this paper was prepared was started as the result of the growing need throughout the world for increasing quantities of energy in all forms. Quite obviously, natural forms of energy that are readily available at low development cost are those in greatest demand. The underdeveloped countries — and particularly those having little or no petroleum resources — are the countries in which the most interest is being shown in the newer energy sources. One of the least expensive energy sources is natural geothermal steam.'-* Although this form of energy has been recognized for centuries, it has been only during the past 20 years that serious efforts have been made to harness it. Natural geothermal steam energy in Italy, New Zealand, Mexico, Japan, and California is now being produced through wells to drive turbines and generate electricity. Further, active exploration for natural geothermal steam is being conducted in Hawaii, Fiji, Taiwan, Chile, Russia, Greece, and Katanga. It is surprising to find that most geothermal steam exploration is in the "steam seep" stage. That is, surface studies are made and exploratory wells are drilled in the general area of steam seeps. However, in the larger geothermal steam areas, there have been efforts to apply the most modern geological and reservoir engineering principles in order to define the reservoir parameters, particularly those relating to estimates of reserves and future productivity. This paper is concerned with the development of appropriate equations and techniques to facilitate these estimates. Production of natural steam or hot water presents problems different from those experienced in the production of oil and gas. For example, steam or hot water systems may be essentially single-component systems, while hydrocarbon systems are most frequently multicomponent fluid systems. Heat effects are much larger for water than for hydrocarbon systems; and the natural steam production may or may not be isothermal, while production of petroleum reservoirs is considered normally to be isothermal. Petroleum reservoir engineering principles may be applied to natural steam or hot water reservoirs if the inherent differences in the systems are considered. The basic considerations involved in geothermal steam reservoir engineering are: thermodynamics, physical and thermal properties of water, materials and energy balances, fluid influx, and performance matching and predicting. Thermodynamics Fig. 1 is a pressure-temperature diagram for the liquid-vapor region for pure water, showing the critical point and five other points representing possible initial conditions for a geothermal steam reservoir. To generate a physical appreciation for the mechanics of natural steam production, it is helpful to consider

Jan 1, 1970

By H. O. McLeod, J. M. Campbell

Data analysis of pentane and hexane adsorption from natural gas in a fixed bed of silica gel shows that constant length mass transfer zones form, the curvature of the adsorption isotherm controls the growth of the mass transfer zone and surface diffusion of molecules inside the silica gel particle controls the mass transfer rate. Curvature of the hexane isothem is more than the curvature of the pentane isotherm. Because of this curvature the hexane adsorption zones reached a constant length. In contrast, the pentane adsorption zones were always increasing in length during each run. A procedure was developed to obtain correct mass transfer coefficients using effluent curve slopes. These transfer roefficients increase with the amount of hydrocarbon adsorbed on the silica gel particle. The characteristic shape of the hexane effluent curves also show that molecular diffusion inside the silica gel particle controls the adsorption rate of pentane and hexane. INTRODUCTION The purpose of this study was to determine the mechanisms that control the dynamic adsorption of hydrocarbons from a natural gas onto silica gel. Before one can deal effectively with multicomponent adsorption, the transfer mechanisms by which a single hydrocarbon component is adsorbed from the gas stream must be defined. Two principal investigations of this system have been published ' and indicate that diffusion through the gas around the particle controls the adsorption rate. Some of the experimental observations in each study either do not support this transfer mechanism or are inconsistent with the mathematical model used in analysis. In this study surface diffusion of molecules inside the particle controls the mass transfer rate of pentane and hexane. This mechanism is indicated by the effluent curve shape for a constant length transfer zone and by the variation of the mass transfer coefficient with concentration of the adsorbed hydrocarbon. THEORY AND DEFINITIONS — MATHEMATICAL MODELS Mathematical solutions for the isothermal adsorption of a trace component from a carrier gas are derived from three relationships: the mass balance or continuity equation, the equilibrium relationship between the gas and solid phases, and a mass transfer rate equation. The transfer rate is proportional to the adsorbate concentration gradient within either the gas or solid phase. Mathematical solutions of these equations usually give the adsorbate concentration as a function of time and distance from the bed inlet. That part of the bed in which the adsorbate concentration changes from a maximum to a minimum value is called the transfer zone. This transfer zone is directly related to a plot of the effluent concentration vs time which has a characteristic S-shape. This general shape is determined by the continuity equation and occurs in many processes of diffusional transfer.

Jan 1, 1967

By R. F. Shurtz

The problem of estimating the precision of systematic samples from a mineral deposit is attacked by interpolating the quality, or other attribute measured, by using Fourier approximation. Such approximation using trigonometric functions yields a particularly simple expression for the variance of the mean value of the attribute sampled. The increasing volume of publication in which the science of statistics has been applied to the problem of predicting the quality of an ore deposit from sets of samples taken from it might lead one to believe that engineering judgment can be replaced by statistics. There is, in fact, an implicit application of the principle of indifference or of "no advance knowledge" which has been discredited in modern statistical theory and practice. These pages will show that it is not always advantageous, efficient, or safe to apply this principle. This problem will be dealt with by using series of orthonormal functions to describe the distribution of the quality of ore in space as contrasted with the more commonly used distribution of quality as a frequency function. Mining engineers are rarely well acquainted with the use of such series or of the functions comprising them. These uses are commonplace in the fields of communication and information theory and it is not surprising that applications taken from these fields should be found appropriate for the analysis of the information contained in a set of samples from an ore deposit. It is hoped that presentation of the following basic, but incomplete, results will generate wider interest in this method and a fuller development of it as well as of the necessary computational techniques. FUNDAMENTAL PREMISES Random variables in the strictest sense are not very common in mine sampling. The sets of samples are almost always taken systematically and are, hence, not subject to all the laws governing random events. Therefore, unless there is indeed random experimental error in the determinations of quality, the treatment of systematic samples of n members as though they were random samples of n members often leads to calculation of confidence limits for the mean quality which are larger than they should be with the result that unnecessary additional sampling is done. The reason for this will emerge in the following discussion leading to Eq. 24 and its generalization. In order to inquire into such questions on a rigorous basis and at the same time avoid arithmetic complications that would obscure the concepts involved, a one dimensional distribution of quality will be assumed. The quality, Q, in suitable units is expressed as a function of the distance, x, along some straight traverse of the deposit. Such a function

Jan 1, 1967

By J. F. Shea, O. F. Tangel

Battelle Memorial Institute participated in a program for the General Services Administration aimed at developing a nickel-cobalt separation process that could be integrated in the Nicaro nickel plant. At the time the programwas being carried out, the Nicaro process was a straight-through operation, in which the ore was reduced and leached, after which the pregnant solution was boiled to produce a so-called "bulk precipitate" which contained virtually all of the nickel and cobalt which had been dissolved in the leaching step. The weight ratio of nickel to cobalt in Nicaro ore is approximately 15 to 20:l. The weight ratio of nickel to cobalt in the finished product had to be 100:l or higher to meet specifications. Because the Nicaro process embodied no nickel-cobalt separation step, the only way that a bulk precipitate of the specified nicke1:cobalt ratio could be produced was to so adjust roasting and leaching conditions that nickel would be selectively leached and most of the cobalt would be rejected with the tailings. The required selectivity, however, was achieved at the expense of nickel recovery, which was 5 or more per cent less than might have been obtained with the existing equipment, utilities, man power, etc., had selectivity been no object. The over-all purpose of the program was to develop a separation step that could be fitted into or onto the Nicaro facilities and which would permit the manufacture of a product that would meet the desired specifications and still permit the recovery of a maximum amount of nickel. Battelle suggested that this might be accomplished by reprocessing off-specification bulk precipitate and specifically suggested the process based on ammonium sulphate leaching followed by hydrogen reduction of the leach solution according to techniques developed commercially by Sherritt Gordon Mines Limited. Such a process would not only satisfy the objectives of the research but would present two additional advantages. (1) It would produce a separate cobalt product which could be further processed into metal, alloys, oxides, or salts. (2) It would yield nickel in metallic form which might be more generally marketable and command a slightly higher price per unit of nickel than the Nicaro oxide product. DESCRIPTION OF THE PROCESS Figure 1 is a flowsheet of the process. The essential features are: (1) Extraction of about 97 per cent of the nickel and about 85 per cent of the cobalt from bulk precipitate by a principal leach with ainmonium sulphate solution (Step A). Extraction of virtually all of

Jan 1, 1961

By R. Schuhmann

Jan 1, 1965

By R. J. Charles

SEARCH for a consistent theory to explain the relationship between energy input and size reduction in a comminution process has accumulated, over the years, an enormous amount of plant and laboratory data. Although some correlation of these data has been possible for purposes of engineering design and for the advancement of research in fracture, there is still great need of a means of predicting behaviour of a solid when it is reduced in size by mechanical forces. The best known hypotheses proposed to describe the energy-size reduction relationships in crushing and grinding stem from a common origin. The present article analyzes problems of comminution in the light of the precepts of this origin. Its object is to reconcile points of difference between these well known hypotheses and to present relationships more widely applicable to comminution studies.

Jan 1, 1957

By C. J. Delisio

The basic concept of tunnel boring has not changed since the late 1800's. R. Stanley of Great Britain obtained a Canadian patent as early as December 1891. Mr. Stanley's machine was a device that consisted of a rotating wheel equipped with drag-type teeth; it had a means of thrusting the cutterhead against the face or heading; it had a means of clamping or gripping the machine in its bore; it had a means of collecting and depositing the cuttings into a screw-type conveyor located near the invert of the tunnel. It even had a means of varying the speed of the forward motion of the machine to suit different hardnesses of rock encountered. This description essentially fits the latest tunnel-boring machines being built today. In short, there has been no significant advance in the basic concept in 70 to 80 years. It may well be that no significant change can be expected for some time into the future. Today's machines, while still basic in concept, offer many advances aimed at faster tunneling. Among these are 1 ) improved cutters, 2) guidance and steering devices, 3) dust-control devices, and 4) mechanisms to aid in installing tunnel supports. CUTTERS The most important part of a hard-rock tunnel borer is the cutter. If the cutter can cut the rock, it is a boring machine. If the cutter cannot cut the rock, no other part of the machine can. When Jarva, Inc. decided to build a machine, the first problem was to find a good cutter. In our search, we looked at most of the cutters on the market. We selected Reed Drilling Tools' cutter because the design of their cutter was aimed at hard-rock tunneling. We feel that they build the best cutter available and provide the best possible service to their customers. As tunnel-boring machine design advanced, the transition from drag bits to roller bits was natural because harder formations required a roller bit, and it is the goal of all mole users to bore harder formations. Roller bits

Jan 1, 1970

Robert Carl Sticht, member of the Institute since 1886, an American metallurgist of world-wide reputation, died in St. Margaret's Hospital, Launceston, Tasmania, on April 30, 1922, after an illness of eleven months, against which he fought with the highest courage and characteristic fortitude. The news of his passing came as a great shock to a host of his friends and former associates here, but on account of his long absence from the United States, exact biographical details have been heretofore lacking. Throughout Tasmania, the expressions of public sorrow were many and impressive, and the flags were flown at half-mast in Queenstown, Zeehan, and the entire Mt. Lyell district, in honor of the man who had won his place in the community as a great captain of industry and a man universally admired and loved. Sticht had been connected with the Mt. Lyell Mining & Railway Co. in Tasmania throughout its entire productive period. He had originally been induced to go to Tasmania through the good offices of the late Dr. E. D. Peters, then professor of metallurgy at Harvard University, who after personally examining the undeveloped Mt. Lyell properties, recommended Sticht as the best possible man to work out the complex metallurgical problem which that great orebody presented. Sticht had already made himself the leading authority on pyritic smelting, having taken up the idea as suggested and partly worked out by Lawrence Austin and carried it through to a certain degree of perfection in the case of limited tonnages of special ores. After studying the situation at Mt. Lyell, Sticht found the conditions there to be almost ideal for pyritic smelting, and he had the courage to adopt as the basis for a permanent, and eventually successful, solution of the metallurgical problem, a process that was then little more than a theoretically interesting possibility. The thorough studies and remarkable results attained at Mt. Lyell were published as chapters in Doctor Peters' various publications on the metallurgy of copper, Doctor Peters giving full credit to Sticht for their authorship. These chapters by Sticht practically constitute the: best literature of the art of pyritic smelting. The accuracy of observation,

Jan 1, 1923