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By C. R. Holmgren

A large consolidated sand core was used in this investigation. Four groups of experiments including gas drives, water drives, and water drives combined with gas injection, were made. The results of the gas-drive experiments indicate that greater ultimate recovery may be obtained by higher pressure gradients. However, other considerations challenge the absolute veracity of this conclusion. Results indicate that with connate water present and a low pressure gradient during a gas drive, less gas is required to produce a given amount of oil. The saturation gradient determined during a gas drive is presented. Results of the water-drive experiments indicate that the recovery of oil is not a function of either gradient Or input rate. The presence of initial gas saturation resulted in a slightly lower final oil saturation. Injection of sufficient gas to maintain the initial gas saturation during a water drive resulted in lower final oil saturation. Introduction With the demand for petroleum products reaching an all-time record high and the location and exploitation of new reserves becoming more difficult and expensive, the oil industry must look to more thorough and efficient methods of producing the petroleum already located. Much of the previous work along these lines is exploratory and suggests a more complete investigation. For example, a great amount of laboratory work has been done on flooding sands initially saturated roo pct with oil. Since sands saturated roo pct with oil rarely, if ever, exist in nature, and because the water content is a vital factor in the ultimate recovery from the sand, laboratory investigations on cores without water must be supplemented by comparable work on cores with water present.1'2 Other investigators have done a considerable amount of laboratory work using gas and water drives.3 Krutter and Day4 have reported results of investigations using cores saturated IOO pct with oil and have concluded that " the ultimate recovery obtained, using air drive, from a completely oil-saturated core depends on the pressure gradients used. The higher the pressure gradient, the greater will be the recovery until a certain Pressure range is reached above which the reward of increased recovery is much smaller for similar increments in pressure." Yuster and Day6 conclude that less gas and less time are required to produce a given quantity of oil at high pressure gradients than at low pressure gradients; they also conclude that an increase in the viscosity of the oil requires a proportionate increase in the gas needed for recovery. Their results indicate that the gas required to produce a given quantity of oil is greatly reduced by the presence of connate water. R. C. Earlougher2 concluded, based on results of water-flooding a large number of

Jan 1, 1949

By D. H. Davis

There are two general types of oil flotation processes, froth and bulk-oil. In froth flotation, the coal concentrates are removed in the form of a froth or foam composed of air, liquid, and solids. Mechanical or pneumatic agitation of a coal slurry with suitable frothing agent causes a selective action of the bubbles to the coal particles which are carried to the upper portion of the pulp in the flotation cell; the refuse is wetted by the water and does not rise with the froth, but goes out as tailings. The other type of flotation process, bulk-oil, consists of thoroughly mixing the slurry or pulp with 30 to 50 pct of its weight of oil. The coal agglomerates with the oil and drops to the bottom of the cell while the refuse is wetted by the water and is carried away in suspension. The concentrate granules may be screened and drained to 12 to 15 pct moisture. The minus 200 or 300-mesh is very effectively treated by this process. The Trent process is a bulk-oil type which has been used for coal cleaning on a commercial basis, but its use has been discontinued in this country. Froth flotation of bituminous coal should be subdivided into two distinct fields: (I) separation of a dry coal product such as recovered from an aspiration system; (2) separation of a minus 48-mesh slurry such as produced from a thickener in a wet cleaning plant. The capacities, performance, and general operating characteristics are very different in these two fields. The recirculated slurry in a washery becomes oxidized and is much harder to treat than a dry dust. It is difficult to clean a slurry containing an appreciable percentage of plus 48-mesh without also floating some high-ash clays minus 200-niesh in size. On the other hand, while working with an aspirated dust, good results have been obtained in floating coal as coarse as 3/16-in. Because of the relatively low capacity of flotation machines as compared with conventional fine-coal cleaners .and because of the greater quantity of reagents required to float coarse coal, there is usually no point in considering flotation on bituminous coal for anything coarser than approximately 48-mesh. In some coal-cleaning plants, good separations are being made down to 80 or even 100-mesh by a less expensive system of coal cleaning than flotation. The Pittsburgh Coal Co. carried out extensive tests on laboratory batch machines and on small units of both pneumatic and mechanical agitation types from 1930 to 1935 and have operated six, eight, and then twelve mill-size mechanical subaeration cells from 1932 to 1944 This paper will deal with some of the operating phases and results of coal-flotation practices as derived from this experience, and more specifically with the flotation practice at the Champion No. I preparation plant. The experience gained from the research and initial experimental work contributed greatly to the successful operation of the mill-sized flotation units at Champion.

Jan 1, 1949

By M. L. Hammond, G. M. Bowers

Silicon dioxide films have been prepared on silicon wafers by the oxidation of SiH, near 400°C. Results previously reported by Goldsmith and Kern7 have been qualitatively corrobovated using a system of different geometry, and significantly greater deposition rates have been achieved. The deposition rate is independent of thickness and nearly independent of the O2/SiH, ratio over a wide range; however, the rate is strongly temperature-dependent. The structure of the deposit depends upon the cleanliness of the substrate, and the electrical field strength of the deposited oxide depends upon the nature of the electrodes. MULTILEVEL interconnects in integrated circuits using aluminum metallization require an insulator that can be deposited at low temperature. Because the A1-Si eutectic is only 577°C, the maximum deposition temperature must be below about 500°C to prevent reaction of the aluminum with the silicon and with other materials in the integrated circuit. Many methods of depositing insulating films of SiO, and other dielectrics have been reported'-6 but the technique described by Goldsmith and Kern7 offers the simplest method of preparing SiO, films. The technique involves the reaction of SiH, and 0, to form SiO, films in the 300" to 500°C temperature range. Previous work using this gas system has been reported8 and the initial development work at Philco Microelectronics was done at the East Coast R&D Laboratories. 9 This paper corroborates some of the results of Goldsmith and Kern,7 shows that much higher deposition rates can be obtained than previously reported, and presents some observations on the structure of deposited SiO, films. EXPERIMENTAL CONDITIONS Fig. 1 is a schematic drawing of the apparatus used in this study. It differs from that of Goldsmith and Kern in that 1) the gases are mixed before they enter the reaction chamber, 2) there is no fritted glass diffuser, and 3) the wafers are stationary during deposition. The control thermocouple was in a well located 0.06-in. from the substrate, and three gas supplies were used: 1 pct SiH4 in N 2, O 2, and N 2. Water vapor must be excluded from the plumbing to prevent the formation of colloidal SiO, and the SiH4 must be diluted with an inert gas because SiH4-0, mixtures are extremely flammable above about 4 pct SiH The wafer temperature was determined by attaching a thermocouple to a test wafer and the temperature was maintained to +5 C. The conditions used in this investigation are listed in Table I. The temperature range was chosen for compatibility with the A1-Si system. The volume ratio of 0, to SiH4 is the actual volume of 0, delivered to that of SiH4, taking into account the initial dilution of the SiH4. This ratio, which was used by Goldsmith and Kern,7 is a useful indicator of the experimental conditions. The active/inactive ratio is the ratio of the volume of active gases, SiH4 and O2, delivered to the volume of dilution gas. The active/inactive ratio is an important parameter to specify for deposition rate determinations since it determines the amounts of reactants that arrive at the sample per unit time. Fairly high dilution ratios were necessary to achieve uniform deposits of SiO,. Most of the process characterizations were performed on the polished (111) face of 3 to 5 ohm-cm, n-type silicon wafers which were 0.009 in. thick; but the data approximately apply to deposition of SiO, on thin films of aluminum. It is difficult to obtain accurate deposition rate data over aluminum films because of coarsening the aluminum surface during exposure to 300" to 400°C. The deposited SiO, film fol-

Jan 1, 1969

By Matsubara, A.

THE problem of the equilibrium between iron, carbon, and oxygen was first carefully investigated by E. Baur and A. Glaessner,1 who determined the equilibrium conditions of the two reactions Fe304 + CO ? 3FeO + C02 (1) FeO + CO ? Fe + C02 (2) within the range of temperature of 350 to 900° C. The next series of investigations was made by R. Schenck and his co-workers,2 who sought to check the results of Baur and Glaessner's work within the range of 550° to 700° C. and to elucidate the conditions of formation of iron carbide. The equilibrium conditions at the higher temperatures, however, are generally understood to be much more complicated, owing chiefly to the formation of solid solutions between iron, its oxides, and carbide; nevertheless their determination is of much more practical importance than those at the lower temperatures. It is well known that each of the reactions is reversible; equilibrium is established when the partial pressure of oxygen in the gaseous phase has become equal to the dissociation pressure of magnetic oxide in equation 1 and that of ferrous oxide in equation 2. These equilibria are subsequently designated by "the Fe304-FeO equilibrium" and "the FeO-Fe equilibrium," respectively. As the Fe304-FeO equilibrium has three phases with three components, it must be bivariant. But the reaction involves no pressure change in the gaseous phase, hence the final composition of the latter is practically unaffected by pressure. To know, the equilibrium conditions, the compositions of the gaseous phase at different temperatures must be determined. At the higher temperature, however, iron and its oxides dissolve one another in various proportions forming solid solutions; in many cases the content of oxygen in the solid phase becomes a new independent variable.

Jan 2, 1921

By E. P. Mathewson

DURING the past 35 years it has been my privilege to deal with hundreds of recent graduates from engineering schools all over the world. In consequence, I, feel that I have learned something about the training of, engineering students. In the first place, I believe that too great specializa-tion is a mistake. A student should receive general training in engineering for at least three out of the four years of the course, and any specializing that may be required should come in the fourth year. Too great emphasis can not be laid upon the fact that the four years' training does not make an engineer; on the contrary, the graduate is only fitted to enter the pro-fession. He becomes an engineer in the true sense of the word only after years of practice; the college train-ing merely shows him where to look for information and develops his intellectual powers. Some of our engineering schools have lengthened the term of study to five years and talk of increasing it still further. This, in my opinion, is a mistake. A young man who spends more than four years in college is apt to become too academic and theoretical. It is better to stiffen the matriculation examinations than to prolong the years of study in college. No matter how good the faculty may be and how carefully selected the course of study, the graduate can never become an engineer unless he has some natural qualifications for the vocation. There are one or two subjects in which most recent graduates seem to be weak; these are accounting, the command of English, and training in the writing of reports. A short course in general accounting should always be included in the curriculum. To this should be added instruction in the preparation of estimates and cost statements. In making reports it should be borne in mind that these reports are to be submitted to busy men,-and not to technical men. The busy man wants the gist of the report summarized on the front page of the report. He wants to know that if he expends a certain sum of money in a certain way, he will get certain results and make so much profit. This should be put clearly before him in short statements, free from technical terms. The details of the report can follow .at greater length; it should be remembered that the employer is not going to read these details, but will confine his attention to the summary.

Jan 1, 1923

By C. Norman Bowers, Blaine B. Wescott

MARKED improvement in the serviceability of sucker rods has been effected in the last two years, partly because of the insistent necessity for greater economy in the operating costs of crude oil production growing out of the general industrial depression and partly because many of the recently developed fields have imposed more severe operating conditions upon both surface and underground equipment. The latter is particularly true of Kansas, where practically all of the oil produced. is associated with damaging amounts of hydrogen sulfide brine and where the method of establishing potential production demands equipment capable of being operated at maximum capacity without interruptions. The decline of flush production in the Oklahoma City field created new problems in deep-well pumping on a scale heretofore unequaled and the increased proportion of water it has been necessary to produce in the fields of the Greater Seminole area presented conditions that were acutely in need of betterment. The problem in the latter fields was complicated by the shift towards sulfide characteristics, which accompanied water encroachment, and it is probably true that nowhere, at the present time, are pump¬ing conditions generally as severe as in this territory. The Mid-Continent district, therefore, has become the proving ground for the numerous materials that have been proposed for sucker-rod fabrication. The information that ultimately will be obtained from an unprecedented amount of field experimentation will pay ample dividends when the decline of East Texas increases the demand for the vast reserves of sour crude in West Texas. It is a rare occurrence in industry that the use of such a simple piece of equipment as a sucker rod presents so complicated a problem for solution. As proof of this, it is only necessary to consider the numerous types of sucker rods on .the market at the present time and contrast this condition with that of less than four years ago, when it was the common aim of manufacturers to develop a single sucker rod for all conditions of

Jan 1, 1935

By H. H. Lowry

SCIENCE attracts the attention and interest of an individual or an industry in general only in proportion to the apparent direct application to its immediate welfare or benefit. Engineering accomplishments, as applied science, therefore receive more recognition than the scientific discoveries on which they are based. Even self-evident truth needs endless repetition before recognition: engineering as applied science cannot advance beyond the science on which it is founded. Scientific research, and discovery, is sometimes forced by the limitations recognized by those active in its development for the use of society and industry and sometimes results from an apparently superficially illogical curiosity about natural phenomena. Research has received inadequate support except in industries born in the laboratory, the chemical and electrical industries, from which many lessons might well be drawn by their elder associates. The rapid growth of these industries has been largely due to close cooperation of scientists and engineers. Most rapid advance is made when the research worker and the engineer keep in close touch with each other's ideas and problems. Many of the developments of modern industry are based on dis-coveries buried for years in scientific journals because the "time was not ripe" at their discovery. The situation with regard to utilization of coal is quite the opposite. The fundamental facts in regard to the scientific aspects of the problem of developing the energy from coal are scarcely known. The engineer, without much scientific cooperation, has accom-plished much in increasing the number of kilowatt-hours per pound of coal from 0.31 in 1919 to 0.69 in 1934, in increasing the 1000 gross ton-miles of freight hauled from 6.1 to 8.3 per ton of coal in the same period, in fuel economy in production of coke, and in developing the production of motor fuel in Germany and England by hydrogenation of coal. This lack of scientific research on the utilization of our most important natural resource, coal, has been due undoubtedly in large part to the reluctance of investigators to study the interrelationships involved in, the complicated processes in which coal is used. These complexities are made

Jan 1, 1936

By H. H. Lowry

Science attracts the attention and interest of an individual or an industry in general only in proportion to the apparent direct application to its immediate welfare or benefit. Engineering accomplishments, as aphlied science, therefore receive more recognition than the scientific discoveries on which they are based. Even self-evident truth needs endless repetition before recognition: engineering as applied science cannot advance beyond the science on which it is founded. Scientific research, and discovery, is sometimes forced by the limitations recognized by those active in its development for the use of society and industry and sometimes results from an apparently superficially illogical curiosity about natural phenomena. Research has received inadequate support except in industries born in the laboratory, the chemical and electrical industries, from which many lessons might well be drawn by their elder associates. The rapid growth of these industries has been largely due to close cooperation of scientists and engineers. Most rapid advance is made when the research worker and the engineer keep in close touch with each other's ideas and problems. Many of the developments of modern industry are based on discoveries buried for years in scientific journals because the "time was not ripe" at their discovery. The situation with regard to utilization of coal is quite the oppositre. The fundamental facts in regard to the scientific aspects of the problem of developing the energy from coal are scarcely known. The engineer, without much scientific cooperation, has accomplished much in increasing the number of kilowatt-hours per pound of coal from 0.31 in 1919 to 0.69 in 1934, in increasing the 1000 gross ton-miles of freight hauled from 12.2 to 16.4 per ton of coal in the same period, in fuel economy in production of coke, and in developing the production of motor fuel in Germany and England by hydrogenation of coal. This lack of scientific research on the utilization of our most important natural resource, coal, has been due undoubtedly in large part to the reluctance of investigators to study the interrelationships involved in the complicated processes in which coal is used. These complexities are made

Jan 1, 1936

By H. H. Lowry

Science attracts the attention and interest of an individual or an industry in general only in proportion to the apparent direct application to its immediate welfare or benefit. Engineering accomplishments, as aphlied science, therefore receive more recognition than the scientific discoveries on which they are based. Even self-evident truth needs endless repetition before recognition: engineering as applied science cannot advance beyond the science on which it is founded. Scientific research, and discovery, is sometimes forced by the limitations recognized by those active in its development for the use of society and industry and sometimes results from an apparently superficially illogical curiosity about natural phenomena. Research has received inadequate support except in industries born in the laboratory, the chemical and electrical industries, from which many lessons might well be drawn by their elder associates. The rapid growth of these industries has been largely due to close cooperation of scientists and engineers. Most rapid advance is made when the research worker and the engineer keep in close touch with each other's ideas and problems. Many of the developments of modern industry are based on discoveries buried for years in scientific journals because the "time was not ripe" at their discovery. The situation with regard to utilization of coal is quite the oppositre. The fundamental facts in regard to the scientific aspects of the problem of developing the energy from coal are scarcely known. The engineer, without much scientific cooperation, has accomplished much in increasing the number of kilowatt-hours per pound of coal from 0.31 in 1919 to 0.69 in 1934, in increasing the 1000 gross ton-miles of freight hauled from 12.2 to 16.4 per ton of coal in the same period, in fuel economy in production of coke, and in developing the production of motor fuel in Germany and England by hydrogenation of coal. This lack of scientific research on the utilization of our most important natural resource, coal, has been due undoubtedly in large part to the reluctance of investigators to study the interrelationships involved in the complicated processes in which coal is used. These complexities are made

Jan 1, 1936

By C. R. Knopp

Gas-oil relative permeability ratio is an important relationship in oil reservoir predictive calculations. A correlation has been developed from 107 gas-flood k/k tests on Venezuelan core samples. The correlating parameter is based on restored-state water saturation tests and' is applicable to both consolidated and poorly consolidated sandstone reservoirs. Data of the correlation show that there are no distinguishah1e differences between the mass-data groupings for the two c1assifications A procedure is recommended for running .sufficient relative. permeability analyses to compute a geometric mean of the sample group. The geometric mean is more representative of the total core, and probably the entire reservoir. For example, while only one in four of the k,,/k,., test curves agreed closely with the resultant correlation of this report, the geometric mean curves of the 16 suites (three samples or more). showed good agreetment ill three cases out of four. INTRODUCTION The gas-oil relative permeability ratio is an important, fundamental relationship in most oil reservoir predictive calculations. Predictive calculations are made to estimate future reservoir production characteristics and ultimate oil recovery. The k1,/k2, relationship is specifically needed to relate the surface gas-oil ratio to the reservoir oil and gas saturation, and to calculate the relative movement of these phases within the reservoir whenever some of the more complex driving mechanisms are present. Laboratory k1/k2, tests are not generally run as a routine analysis. Consequently, k1/k2 data often are not available when needed because the cost of laboratory work could not be justified or the need for such data had not been properly anticipated. When laboratory k1/k2, data are available, they are often very difficult to interpret. For example, wide divergence is sometimes shown in a family of k1,/k1, tests representative of the producing horizon in a single well. With these considerations in mind, a study was made to determine if a relationship might exist between the k1,/k2, curve and some other simple laboratory test criteria. The most probable k1/k2, curve correlation for Venezuela described in this paper is the result of the investigation. The presented correlation defines the most probable gas-flood k,,/k,, curve through the medium of air-water capillary displacement and centrifuge water saturation tests. The laboratory procedures of these tests are. relatively simple, and inexpensive; test data should be. widely available- from routine analysis. DATA AVAILABLE, LABORATORY METHODS The report correlation utilized 107 gas-Hood k1/k2, tests run on sandstone cores of Venezuelan reservoirs. Table 1 is a general tabulation of data pertinent to the tests, while Table 2 summarizes the data. Thetests include 96 from Western Venezuela and 11 from Eastern Venezuela. Eighty-two- of the 107 test samples were sandstones that varied from poorly consolidated to-unconsolidated; 25 were consolidated. The average sample porosity was 26.7 per cent and the average permeability was 1,121 md; these values typify the better sandstone reservoirs of' Venezuela. The Welge gas-flood technique,' based on fundamental Buckley-Leverett frontal displacement theory, was introduced in about 1952 and is widely accepted in the industry. The laboratory procedure is relatively simple, rapid, and can be performed on small core samples. While there have been some minor variations in sample preparation and laboratory procedure in the tests used for the correlation, these tests can be generally summarized as follows. The core sample was first sol vent-extracted and dried. Connate-water saturation was restored by the oil-flushing or evaporation-blow down methods. At the beginning of gas flood the hydrocarbon pore volume was completeiy saturated with the test oil phase. Unsteady-state gas-oil displacement then began with the injection of nitrogen or helium. while the displaced oil and gas phases were incrementally metered at the out-flow face. From the test data, the k,,/k,, curve was calculated by the Welge method.' The individual oil and gas relative permeabilities were also calculated." CORRELATING PROCEDURES In attempting to establish a basis of correlation, we found that broad mid-range sections of 105 of the 107 k,,/k,, test curves could be closely duplicated by a straight line. Only two curves did not show a degree of linearity in this region. Correlation-curve definition parameters were subsequently developed from this observation of consistent mid-range linearity. Possible correlating variables were limited to the physical properties measured on core samples that (1) were widely available as common test data and (2) could be easily and cheaply obtained through future laboratory work. The more obvious possibilities were porosity, permeability and

Jan 1, 1966

By C. P. Melloy

INTRODUCTION Ventilation practice at Isa Mine has been evolving since underground mining began in 1931. Much fundamental work has been conducted and reported regarding the primary ventilation system [Mathews K.E. et a1 (1967) and Brown J.R., Fisher T.H., Gibson K.L. (1979) 1. However, ventilation networks for subsystems such as open stopes, have evolved with experience. This paper outlines current ventilation practice for open stoping. Mount Isa Mine The mine is located in semi-arid North-West Queensland, Australia, and currently produces 20 000 tonnes of copper ore and 10 000 tonnes of silver-lead-zinc ore daily in each five day working week. Mining extends over a north-south strike length of 3.5 km with a maximum width across dip approaching 1 km, and is to a depth of 960 m (Figure 1). At present approximately 90% of the mine's copper production is from the 1100 Orebody, which contains ore reserves of 121 million tonnes of 3.2% copper. Open stoping is currently the mining method employed, and is used for primary stoping and pillar recovery adjacent to cement fill walls. The development of stoping methods in the 1100 Orebody has been documented by Kirkby R.W., Blair J.R., and Hutton R.C. (19781, Hornsby B. and Sullivan B.J. (1978), and Alexander E.G. and Fabjanczyk M.W (1981). As many as thirteen open stopes may be producing concurrently in the Orebody (Figure 2). The multiple silver-lead-zinc orebodies containing reserves of 54 million tonnes of 150 g/t silver, 6.4% lead and 6.5% zinc, are mined by open stoping, and cut and fill techniques. These methods have been documented by Goddard I.A. and Bridges M.C. (1977 1, and Goddard I. A. (1981 1. Only the ventilation of the 1100 Orebody open stopes will be discussed. However, the same ventilation philosophy is employed in open stope design in the lead orebodies.

Jan 1, 1981

By Walter Crafts

Tests carried out at the Union Carbide and Carbon Research Laboratories, Inc., on the effects of grain-refining deoxidizers are in substantial agreement with the data presented by Mr. Comstock. Notable is the observation that, although boron and aluminum increased hardenability, the steel was of poor quality in comparison with the other boron-treated steels to which at least two grain refiners were added. The effect of zirconium in improving the ductility of the chromium-nickel steel is in agreement with our experience that zirconium is specifically beneficial to chromium steels. In order to amplify Mr. Comstock's results and to indicate some of the basic principles of special deoxidation, the primary observations of our study have been summarized. The effect of boron in increasing hardenability was described by R. Walther, U. S. Patent No. 1519388, Dec. 16, 1924, but effective amounts in incompletely deoxidized steel are sufficient to harm hot workability and room-temperature ductility. Work at the Union Carbide and Carbon Research Laboratories, Inc., has shown that in order to obtain deep hardening without using such large amounts of boron as to result in impairment of ductility, the steel must be thoroughly deoxidized. This may be accomplished by a high silicon content or a grain-refining addition of strong deoxidizers. The degree of grain refinement and hardenability are inclined to be erratic when only one grain-refining element is used, although aluminum, zirconium, titanium, and vanadium have been used singly and resulted in increased. although somewhat erratic, hardenability. The ductility likewise was inclined to be inconsisterlt when only one grain-refining deoxidizer was added. By combinations of grain-refining elements, it was found possible to combine the specific virtues and counteract some of the defects of each clement. In addition, the complex deoxidizers gave more consistent grain refinement and hardenability. When used in combinations, each element adds its own specific influence as well as modifying the character of the other elements. The function of aluminum is primarily to give consistent results and to minimize abnormalities resulting from too

Jan 1, 1943

By Walter Crafts

Tests carried out at the Union Carbide and Carbon Research Laboratories, Inc., on the effects of grain-refining deoxidizers are in substantial agreement with the data presented by Mr. Comstock. Notable is the observation that, although boron and aluminum increased hardenability, the steel was of poor quality in comparison with the other boron-treated steels to which at least two grain refiners were added. The effect of zirconium in improving the ductility of the chromium-nickel steel is in agreement with our experience that zirconium is specifically beneficial to chromium steels. In order to amplify Mr. Comstock's results and to indicate some of the basic principles of special deoxidation, the primary observations of our study have been summarized. The effect of boron in increasing hardenability was described by R. Walther, U. S. Patent No. 1519388, Dec. 16, 1924, but effective amounts in incompletely deoxidized steel are sufficient to harm hot workability and room-temperature ductility. Work at the Union Carbide and Carbon Research Laboratories, Inc., has shown that in order to obtain deep hardening without using such large amounts of boron as to result in impairment of ductility, the steel must be thoroughly deoxidized. This may be accomplished by a high silicon content or a grain-refining addition of strong deoxidizers. The degree of grain refinement and hardenability are inclined to be erratic when only one grain-refining element is used, although aluminum, zirconium, titanium, and vanadium have been used singly and resulted in increased. although somewhat erratic, hardenability. The ductility likewise was inclined to be inconsisterlt when only one grain-refining deoxidizer was added. By combinations of grain-refining elements, it was found possible to combine the specific virtues and counteract some of the defects of each clement. In addition, the complex deoxidizers gave more consistent grain refinement and hardenability. When used in combinations, each element adds its own specific influence as well as modifying the character of the other elements. The function of aluminum is primarily to give consistent results and to minimize abnormalities resulting from too

Jan 1, 1943

The income of the Institute is derived mainly from dues, advertising in MINING AND METALLURGY and sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion constituting endowments for especial purposes. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd Memorial Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization.

Jan 1, 1939

By E. J. Freeh, W. E. Horst, R. C. Kellner

A technique useful in the important area of process-model building is described. The procedure is illustrated in the development of a mathematical model to describe the unsteady-state process of batch ball-mill grinding. The influence of certain assumptions relative to model structure are quantitatively evaluated and reviewed.

Jan 1, 1969

JOHN W. BELL (communication to the Secretary*).-I have to thank Mr. Merrill not only for his very kind remarks, but for the weight of his implied opinion that the work accomplished probably has an important practical aspect. I think there is a distinct although unuttered impression among engineers, that it will be time enough for them to begin to take an interest in the law of crushing when it emerges from the cloud of violent and even vituperative controversy that has hovered over it during the last 6 or 7 years. I have a very confident feeling that as the result of the work done by Mr. Gates, by me and by Messrs. Mitchell, Baily and Cockfield, who so loyally helped me to obtain the necessary data, at least the practical law of crushing has emerged; that it is ready and available for use by our fellow engineers, and that it will help them to unravel a number of the many practical problems they are con¬stantly confronted with. In regard to Mr. Gates' discussion, I would indeed like to believe that McGill could claim, as a minor achievement, the credit which Mr. Gates so generously bestows of having established the "law" of crushing. I think that more work would be required to establish this claim in the, strict sense of the word, as there is a fairly large gap between the coarse and fine crushing results. I am not worried about that gap, because the reason for it is quite clear to me; at the same time I-think it will be well to bridge it by a series of tests, and I am bound to admit that the testing machine is the most promising machine right at hand to work with, although whether the minute amounts of power required to crush small quantities of rock can be so accurately integrated as to insure high accuracy in the final result is still a question in my mind. If we had an Amsler-Laffon machine I would certainly try it. Mr. Gates' remarks about choke crushing are extremely interesting. He compels me to wonder, too. It is a new and probably a very important factor to be considered in this connection. I am in perfect accord with Mr. Gates about the desirability of the determination of crushing constants, because when this is accomplished the efficiencies (not relative mechanical, but real efficiencies) of different types of rock-crushing plants in any part of the world will then be comparable. For this reason it would, seem desirable that the American Institute Committee should not only consider ways and means for accom-

Jan 6, 1917

By Akira Ishizu, Nobuo Matsui, Hideo Yamamoto, Tatsuya Nagahama

At Kamioka Mine of Mitsui Mining & Smelting Co., Ltd., Japan there are three mills, treating a total of 6400 t/d of lead-zinc Ore. In the lead-zinc bulk differential flotation at Shikama Mill the addition of reagents is automatically controlled by the feed rate, the lead and zinc content in feed, froth and tailing, the pH and the concentration of cyanide ion in the pulp. As the zinc thickener overflow at Shikama Mill contains CU(CN)3--, ZnS, CdS, CN-, xanthate and frother, all the ingredients in the over- flow other than CN are floated by using the Nagahm flotation machine, and the water containing only CN- is effectively recycled to the lead- zinc differential flotation circuit. In the lead-zinc straight differential flotation at Mozumi Mill, the overflow of tailing pond is recycled especially to the cleaning flotation circuit by decreasing the pulp density. Thus the integrated recycling of wastewater greatly reduces environmental problem and in addition, it generates sizeable profit.

Jan 1, 1977

By Nicholas Kowall, K. L. Clark

Maximum furnace efficiency and close control of final steel composition demand that the steel melter be able to follow closely the variations in the carbon content of the bath. For many years, the fracture test has been used by melters for estimating carbon, because it requires only a very short time to pour a sample into a chill mold, cool it in water, break it with a sledge hammer, and observe the fracture. After long experience gained from the observation of such fractures, most melters are able to estimate the carbon content of steel with amazing accuracy, particularly in the lower carbon ranges. Notwithstanding the utility of the fracture test, there has been widespread interest in other methods for rapid carbon determination to supplement it and to ensure against possible errors in human judgment. Several methods, based upon measurement of magnetic properties as functions of carbon content, have been described in the literature1-6 and have been found to give reasonably reliable results in plant practice when scrap composition is known and controlled. A difficulty encountered in the use of analyzers of the magnetic type is that alloying elements do change the relationship between carbon content and magnetic properties and it becomes necessary to establish calibration curves for all the expected combinations of alloy residuals that are not oxidized in the bath. The work reported here is of an investigation of a method that is independent of alloying elements normally present in constructional steels, being based upon the relatively well-known fact that in plain carbon and low-alloy steels martensitic hardness is a function of carbon content alone. Work oF Other Investigators In I938, Burns, Moore and Archer published & curve? that showed that the hardness of martensite is a function of carbon from 0.10 to 0.50 per cent and is independent of grain size or alloy content, at least within the rallge found in construc-tional S.A.E. compositions. Some of the deeper hardening types investigated, however, contained carbon to a maximum of only o.2o per cent. Using this principle, Kern8 developed a method of rapid carbon determination for S.A.E 43xx steels, His procedure consisted of chill-casting a test bar that was large enough to give a a that could be prepared for Brinell indentations. The test piece was quenched immediately after solidi fication was complete and hardness readings were taken, so that the carbon content could he read from an experimentally determined curve giving the relationship between as-quenched hardness and carbon. Experimental Work Although Kern's work had been done with a relatively deep-hardening steel, it

Jan 1, 1944

By K. L. Clark, Nicholas Kowall

Maximum furnace efficiency and close control of final steel composition demand that the steel melter be able to follow closely the variations in the carbon content of the bath. For many years, the fracture test has been used by melters for estimating carbon, because it requires only a very short time to pour a sample into a chill mold, cool it in water, break it with a sledge hammer, and observe the fracture. After long experience gained from the observation of such fractures, most melters are able to estimate the carbon content of steel with amazing accuracy, particularly in the lower carbon ranges. Notwithstanding the utility of the fracture test, there has been widespread interest in other methods for rapid carbon determination to supplement it and to ensure against possible errors in human judgment. Several methods, based upon measurement of magnetic properties as functions of carbon content, have been described in the literature1-6 and have been found to give reasonably reliable results in plant practice when scrap composition is known and controlled. A difficulty encountered in the use of analyzers of the magnetic type is that alloying elements do change the relationship between carbon content and magnetic properties and it becomes necessary to establish calibration curves for all the expected combinations of alloy residuals that are not oxidized in the bath. The work reported here is of an investigation of a method that is independent of alloying elements normally present in constructional steels, being based upon the relatively well-known fact that in plain carbon and low-alloy steels martensitic hardness is a function of carbon content alone. Work oF Other Investigators In I938, Burns, Moore and Archer published & curve? that showed that the hardness of martensite is a function of carbon from 0.10 to 0.50 per cent and is independent of grain size or alloy content, at least within the rallge found in construc-tional S.A.E. compositions. Some of the deeper hardening types investigated, however, contained carbon to a maximum of only o.2o per cent. Using this principle, Kern8 developed a method of rapid carbon determination for S.A.E 43xx steels, His procedure consisted of chill-casting a test bar that was large enough to give a a that could be prepared for Brinell indentations. The test piece was quenched immediately after solidi fication was complete and hardness readings were taken, so that the carbon content could he read from an experimentally determined curve giving the relationship between as-quenched hardness and carbon. Experimental Work Although Kern's work had been done with a relatively deep-hardening steel, it

Jan 1, 1944

The income of the Institute is derived mainly from dues, advertising in MINING AND METALLURGY and sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion con- stituting endowments for especial purpose?s. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd Memorial Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization.

Jan 1, 1937