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By O. W. Walvoord

Mill design of the past will not necessarily dictate mill design of the future. There have been many advances and changes in the last few decades, many of which have been extensive and remarkable. Almost certainly, there will be still greater changes in the near future. Minerals beneficiation, for example, as it relates to future mill design, is likely to experience the greatest progress. Gravity separation, though one of the older arts, is in a continuous state of refinement. Flotation, having celebrated its 50th anniversary in 1961, has yet to be surpassed in its contribution to the art of mineral dressing. Ion-exchange, too, will flourish.

Jan 1, 1971

By J. B. Darby, P. A. Beck

IN a previous publication,' the 1200°C isothermal section of the Cr-Mo-CO system was surveyed. It was found that starting from the binary (Cr,Co)a, the u phase extends deep into the ternary system in the form of a narrow band, which, when extrapo-

Jan 1, 1956

By J. G. McCullough

The paper is a general description of the U.S. lead and zinc industries as they are now compared to ten years ago and the effect of recent world-wide developments. Topics of interest concerning lead are the present and potential growth of the lead-acid battery business, the potential hazards of having one outlet for a major proportion of production, the expanding U.S. secondary lead production, the hardships of stringent hygiene and environmental regulations and the future supply and demand outlook. The present poor condition of the U.S. zinc industry caused by an oversupply of zinc metal - mostly in Europe - is discussed and also the shifting markets influenced by the automotive programs to reduce the weight of cars and the continuing high mine production due to the mixture of metals contained in the massive sulphide deposits which contain a major portion of the zinc metal reserves. This is all tempered by technical advances in die casting and the emphasis on the protecting of steel with zinc to prolong its useful life. New U.S. mine and smelter production facilities will be restrained due to lower cost foreign zinc from better grade ore deposits and the insistence by Governments for refining capacity to be constructed in the country that the ore is mined.

Jan 1, 1977

By Harold B. Foxhall

THIRTY per cent of the mineral wealth of the United States is obtained from seven states: Arkansas, Kansas, Louisiana, Missouri, New Mexico, Oklahoma, and Texas. This area, which produced 84,727,156,000 worth of minerals in 1948, constitutes an almost complete economic unit in relation to mineral resources essential to industry. All of these states are producers of fuels and some of metallics, but in the field of important nonmetallic industrial minerals the picture is near perfection-a mineral any one of the seven states lacks, one of the others has in quantity.

Jan 5, 1951

The Institute maintains a dual relationship with students: (1) an individual relationship with a Student Associate; and (2) a relationship with local organizations of students, known as Affiliated Student Societies or Student Chapters. 1. The conditions of Student Associateship are set forth in Section 9, Article I, of the Bylaws of the Institute (see page 61 and following pages). During 1934, sundry amendments were made for the purpose of improving

Jan 1, 1939

Albert R. LEdoux, New York, N. Y.—I can add a little to the information which has been given, by saying that it has been our business for some years, among other things, to inspect outgoing copper from some of the works here in the East, and to find out why there are variations not only in the conductivity of the wire-bars, but also in the character of the cathode-copper shipped; and we have found two things: These impurities which have been mentioned are largely upon the surface of the cathode. Samples taken of the inside, even of the nodules or " berries " which grow on the outside of the cathode, show that they do not contain more impurities than the denser material in the interior. In other words, it is a superficial deposit or contamination. There is still another reason for impurity in some of the copper which finds its- way to the manufacturers, namely, carelessness in the handling of molds or in casting. We have found copper which was comparatively pure, as far as the copper itself was concerned, but contained, mechanically intruded in the interior of the ingots,

Jan 1, 1913

By David R. Maneval

At the turn of the century, 90% of the energy output in the United States was generated by coal, and Pennsylvania was the ranking producer of this fuel. With the huge resources of easily accessible coal found by its early settlers, the Commonwealth was the nation's chief powerhouse for nearly 100 years. In 1928 alone, Pennsylvania mined a billion dollars' worth of coal-or enough to fill a train reaching more than twice around the world at the State's latitude. Coal constituted nearly 67% of the freight of Pennsylvania and was responsible for the State's $4-billion iron and steel industry. Pennsylvania was slow to take up its position as the greatest coal-producing state in the union, but the knowledge of its coal assets was not slow in accumulating. In fact, long before the white man arrived, the Indians were aware that many of the hills were underlain by black stones that would burn. But awareness was not enough. The early Pennsylvania settlers confined themselves to the southeastern corner of the State and had little need or concern for resources further inland.

Jan 1, 1971

By D. W. Fuerstenau

Locked-cycle grinding experiments on mineral mixtures provide a means to study circuit performance in simulated continuous grinding systems. Such experiments with calcite/quartz mixtures revealed that approximately twenty-five 2-minute cycles are required before the composition of the circuit product and the recycle material attain steady state. The circulating load, after steadily increasing during the first 15 cycles, continued to fluctuate over a narrow range. Previous batch ball mill grinding of mineral mixtures has shown that breakage rate functions of minerals are time- independent but composition-dependent. In the closed-circuit grinding of ores with constituents having different grindabilities, the grinding rate parameters for the components also would therefore change during the transient period. With fluctuations in feed composition occurring randomly every half to one hour in processing plants, it is quite likely that the grinding circuit can be in unsteady state perpetually. The significance of these observations is discussed in this paper in the con- text of the models used in control schemes for the grinding circuits

Jan 1, 1984

By C. G. Dunn, P. K. Koh

TWO recent review papers have considered the origin of primary and secondary recrystalliza-tion textures from the point of view of oriented nucleation and oriented growth theories."' Both theories require nuclei for primary recrystallization but provide no unequivocal answer to the question of what nuclei are. The answer to the same question regarding secondary recrystallization, however, often is that nuclei are certain primary recrystallization grains or primaries. The two theories differ, however, in specifying what the certain primaries are. In support of the oriented growth theory Beck and Hua originally stated "It may be assumed that in a re-crystallized material, even with a strong texture, there always are present some grains of practically any orientation. These may serve as nuclei for the coarse grains, provided that conditions are favorable for their growth." In commenting on this statement one would say that there are two restricting conditions: namely, that 1) the certain primaries (nuclei) are large enough to grow, and 2) their boundaries have high mobility. More recently Beck2 has con-

Jan 1, 1958

By R. G. Garlick, H. B. Probst

Tungsten single-crystal specimens of various orientations were deformed in tension at room temperature. Slip traces indicated both (112)(111) and (110) (111) slip; however, about 10 pct plastic dejormation was required bejore these traces could he seen. Resolzled shear-stress considerations indicated that at least some of the particular systems observed were not those on which slip initiated hut were secondary systems. This is highly probable, considering the high plastic strains involved. Analysis of the stress data with respect to possible slip systems indicated that slip must have been initiated at stresses below the proportional-limit stresses measured. ALTHOUGH there is general agreement that slip deformation in fcc and hep metals takes place on the plane of close packing and in the direction of close packing, there is no such agreement for slip in bcc metals. It is generally agreed that the close-packed direction (111) is the slip direction, but investigations have led to conflicting descriptions of the slip plane. As Hoke and Maddin1 point out, there are essentially four points of view. 1) Deformation in bcc metals is composite shear on (112) and (110) planes or on nonparallel (110) planes, and any apparent slip on other planes can be accounted for completely by slip on these planes. Chen and Maddin have reported this to be the possible case for molybdenum." 2) Slip occurs in the (111) direction and is limited to {110), {112), and (123) planes (the three closest packed planes of the lattice). 3) Slip occurs in a (111) direction, but not necessarily on planes of close packing (banal slip). 4) Slip occurs in those directions and on those planes for which ß, the ratio of Burgers vector to interplanar spacing, is a minimum. The slip systems of the bcc metal tungsten have never been fully determined, although several investigators have reported pertinent results.3"7 The present work was initiated to determine the active slip systems in tungsten at room temperature, the critical resolved shear stresses associ- ated with these systems, and the orientation dependency of operative systems. These features of tungsten deformation at room temperature have never been reported in the literature. The authors find this somewhat surprising, particularly in view of the availability of tungsten single crystals since the advent of electron-beam zone-melting techniques and the widespread interest in refractory metals. It would seem apparent that such work has been attempted but the results have not been reported, possibly due to the conflict with deformation theory. The results of the present work conflict with any straightforward description of deformation based on the proposed explanations of slip in bcc metals. Although these conflicts have not been resolved, a presentation of the problem seems in order and should be of value to others working in this field. MATERIALS AND PROCEDURE Single-crystal tungsten rods of 1/8-in. diameter were grown from undoped commercial rod by one-pass electron-beam zone melting in apparatus previously described by witzke.8 Representative analyses of the rod before and after melting are given in Table I. There was no detectable zoning of impurities during melting. Buttonhead tensile specimens, as shown in Fig. 1, were machined from single crystals. Two flats 90 deg apart were ground in the gage length of each specimen. These flat surfaces facilitated the analysis of slip traces. No attempt was made to position these flats with respect to the crystal orientation. The worked surface layer of the machined specimens was removed by electrolytic polishing in a NaOH solution. Tensile-axis orientations were determined by standard Laue back-reflection techniques. The sharpness of the Laue spots indicated that the crystals were free of strain.

Jan 1, 1964

In their presentations Dr. Puddington and Dr. Stratton-Crawley have concentrated on spherical agglomeration and two-liquid extraction respectively. I should like here to complete the picture by putting these two techniques together in context with other techniques in which non-polar oils are used in the concentration and separation of minerals. Although these techniques are invariably treated separately and have been studied in isolation, there is a lot to be said for considering them together and trying to systematize their similarities and differences. This I take as a principle guideline in my introduction to this discussion. Four processes can be distinguished on the basis of the dosage of oil required: --simple flotation with collector-extender --agglomeration (emulsion) flotation --spherical agglomeration --two-liquid separation Dr. Stratton-Crawley has suggested that "pigment flushing" could find application in the treatment of ores. This is an interesting suggestion. However, the process can be regarded as a variant of two-liquid extraction, and it is convenient for me to do so in this discussion. Table 1 sets out some main features of these techniques. The first, in which the oil is used to enhance the strength and reduce the dosage of the collector is not designed for and has no special advantages in the treatment of fines, and therefore will not be further treated here. To add to the details appearing in the Table, thumbnail sketches of the other three, which all do show particular efficacy in the treatment of fine particles, are given below.

Jan 1, 1979

By P. Levesque

IN the process of alloying two metals to obtain a single-phase alloy, the end product is nearly always a cored structure. The mechanism of solid-

Jan 1, 1955

By D. M. Given

HOW much can the mine operator afford to spend on his coal burning boiler plant? The usual answer is as little as possible and still get the job done. Thus, attention must be focused on the spot where excessive costs are most likely to arise - the materials handling end of the job. Boiler plants consuming less than 30,000 tons of coal annually can be controlled to the point where costs for handling coal and ashes are under $1.00 per ton. There is a wide selection of coal and ash-handling systems that can be used in smaller boiler plants to provide labor savings and convenience required if management is to accept coal as fuel.

Jan 7, 1953

By L. G. Huntley

The entire production of Colombia for 1927 was that from the Tropical Oil Co. concession. Production was approximately 14,000,000 bbl., of which 12,081,000 bbl. were exported from the Mamonal terminal of the Andian National Corp. near Cartagena. The balance represents that refined and used or marketed within Colombia. As production in 1926 was only 6,443,540 bbl., the increase has been more than 100 per cent. This is partly due to the looping of the pipe line from the concession to the coast, and the resultant increase in capacity to 50,000 bbl. per day, and also to increased domestic sales. The refinery at Barranca has been doubled in capacity, and it is understood is now handling 5000 bbl. of crude daily. This gives the producing field a potential outlet of 55,000 bbl. daily. The Tropical Oil Co. completed 82 wells in 1927, with one abandoned for drilling difficulties. The average daily initial production was 1136 bbl. per well. The largest well is reported to be No. 173 La Cira, rated as 5000 bbl. initial. Most of the wells were drilled on the Infantas and La Cira structures, the latter located en echelon to the northwest of the main Infantas anticline, and separated from it only by a low saddle. Drilling operations on the Llanos fold, also en echelon with Infantas but to the southeast, and at San Luis, bearing about the same relationship to the Umir Hills uplift, are still more or less in the exploratory stage. The four structures mentioned cover approximately 15,000 acres, on which there are at present 223 producing wells. Drilling has been better than 92 per cent. successful since starting operations on this concession. Allowing 15 acres per well, which is 50 per cent. more than good practice in the Mid-Continent fields, there is thus room for 1000 wclls, which at the recent rate is a 10-year drilling campaign. This does not take into consideration the known deeper oil zones, which have not been prospected, but which are uniformly petroliferous at their outcrops to the eastward. It is estimated that with the enlarged pipe line capacity, as well as increased domestic consumption, the production for this country will be about 20,000,000 bbl. for the current year of 1928. It is possible that

Jan 1, 1928

By Carroll F. Hardy

The day by day loss of industrial plants to gas and oil is chiefly by default. The coal industry is not selling its superior economy, safety, and other advantages to its customers. THE position of the coal industry has been affected by a wide variety of developments in the production and use of energy. The tempo of development and change has been increasing and the end is not in sight. Legislation is currently being proposed for commercial use of atomic power, and the employment of atomic energy in significant quantity will probably occur about the same time as the decline in production of petroleum and natural gas. But these developments are in the future and have little immediate effect on utilization and marketing of coal. While no one should try to suppress or retard the development of a new and economical source of energy, both the coal and private utility industry should be allowed to question how the nuclear power is to be used, who is to use it, and who is going to pay for it. The taxpayers have a monopoly on fissionable material and the knowledge to employ it. Any commercial use must stem from this source. It is not hard to visualize either taxpayer-subsidized private utility atomic power plants on one hand and super TVA's on the other. In view of the gains of gas and oil in the home heating field, it is interesting to compare the 1940 and 1950 census reports on the kind of fuel used for heating in occupied dwelling units. Table I shows that whereas coal provided 77 pct of the fuel for central heating (furnaces and boilers) in 1940, it was down to 45.4 pct in 1950. However, only about 1 1½ million units were lost in this 10-year period. In the non-central heating category, which principally includes stoves, the percentage declined from 39.2 to 25.6, but the units declined about 2½ million in number. The big increase was in heating units designed to burn gas and oil. Use of wood for central heating declined about one-third. Data on amount of fuels used for residential heating are not available, but information is on hand for residential and comnlercial space heating, see Table 11. Commercial space heating includes office buildings, churches, schools. and similar structures. The annual use of bituminous coal in these two categories declined about 1 million tons in the 10-year period. Other forms of solid fuel showed greater losses, except wood, which remained the same. Domestic stokers reached their high point in 1948 with about 1,200,000 in use. At the end of 1951 there were approximately 1,116,790 stokers in use. Conversions to gas and oil have been from hand-fired heating plants in the ratio of about 7 to 1 compared to stokers. In other words, for every one stoker which has been converted to gas or oil, seven hand-fired units have been converted to gas or oil. A bare recital of these data would indicate that the coal industry is holding its own reasonably well. However, 93.4 pct of the new homes built in 1951 were heated by gas or oil. Oil-burning equipment was installed in 37.8 pct and gas equipment in 55.6 pct of the new homes. This indicates that the public prefers gas when it is available, and that oil is second choice, with all forms of solid fuel apparently used when it is unavoidable. It must be pointed out, however, that during the period of rapid expansion of gas pipelines gas has been sold for house heating at prices that are in some cases actually lower than coal prices, or very nearly on a par. Gas has been sold at wells at far below the comparable price for oil produced from the same wells, and far below its actual worth. This situation is being remedied at the present time by increases in gas prices at the wells. For example, the wellhead price of gas in Texas averaged 7.494 per Mcf in 1952. In 1949 it was 4.59c per Mcf. This increase in price is being reflected in pipeline gas prices, and in most of the markets served by the pipelines the tendency is to get it out of the bargain basement type of sales. The American Gas Association estimates that at the end of 1952 there were in the United States about 11 million customers for gas house-heating, and the Association expects additional gains each year until around 18 million homes will be heated by gas in 1975. By 1975 there should be 60 million dwelling units to be heated in the United States, if dwelling units increase at the same rate as the population. If the gas industry heats 18 million dwelling units by that time, this still leaves 42 million units to be heated by some other fuel. If oil is used to heat 18 million dwelling units in that same year, 24 million would of necessity be heated by coal, coke, wood, electricity, or another fuel. The total number of dwelling units using coal listed in the 1950 Census was 18,776,000, so it would appear that coal has a chance at least to stand still in the tonnage sold for domestic use. In the first quarter of 1953, 2044 domestic stokers

Jan 1, 1955

State of Indiana, Department of Conservation, Division of Geology, Indianapolis, Ind. W. N Logan, State Geologist A list of the publications will be sent upon request. A series of yearly reports have been issued, with a few early exceptions, since 1869, up to and including the 41st (1916) Five of these are issued free, 18 are out of print, and the rest may be obtained at a quoted price. Beginning in 1917, the administrative reports of the State Geologist have been published in the Indiana Year Book. In 1919, the Department of Geology and Natural Resources became the Division of Geology in the Department of Conservation and separates of later reports in the Year Book are available, as follows. 3rd Report (1921), Gold in Indiana, 4th (1922), The New Albany shale, peat deposits of Indiana; 5th (1923), Petroleum conserva¬tion, 6th (1924), Conservation of natural gas; 7th (1925), Coal losses of Indiana, 10th (1928), Geological conditions in the Siosi oil field, 11th (1929), The mineral fuel resources of Indiana, 12th (1930), Oil and gas developments in 1930. (Titles of lesser interest are omitted ) The following Special Reports have been printed as publications of the Department of Conservation: Special Report 6, Kaolin of Indiana (1919), free; 21, Handbook of Indiana geology (1922), $5 to nonresidents and $3 to residents, 42, Geologic conditions in the oil fields of southwestern Indiana (1924), 75 cents to non-residents and 50 cents to residents; 55, Geology of the deep wells of Indiana (1926), $1; 75, Geology of the Silurian rocks of northern Indiana (1928), $1, cloth bound, 8125, 78, Indiana oolitic limestone map of Monroe-Owens counties (1928), $1, 79, Indiana oohtic limestone map of Lawrence County (1928), $1; 90, The geologic history of the vertebrates of Indiana (1929), $1, cloth bound, $125, 91, The ceramic materials of Indiana (1929), free, 98, The Borden (Knobstone) rocks of southern Indiana (1931), $1 25, cloth bound, $150, 101, Insoluble residue studies of Mississippian limestones in Indiana (1931), 25 cents

Jan 1, 1933

By Morris Cohen

This paper deals with the calculation of the composition of the infinitesimal trace of alloy that transfers from the liquid to the solid state at each temperature during the equilibrium solidification of a binary solid solution, and which thereby enables the compositions of the coexisting liquid and solid phases to follow along the liquidus and solidus lines respectively during the cooling. A general expression for the composition (d) of the liquid-to-solid transfer at each temperature has been derived: d = ZLXL(XL - P) + Zsxs(P- ZL(XL - P) + Zs(P - Xs) where ZL and Zs are the slopes of the liquidus and solidus lines at the given temperature, XL and xs are the composi-tions of the stable liquid and solid phases at the same temperature, and P is the composition of the alloy under considera-tion. The d equation is valid for the process of equilibrium heating as well as cooling, and may be applied to vapor-to-liquid, vapor-to-solid, liquid-to-liquid, and solid-to-solid transfers if the corresponding equilibrium diagrams are known. The d -versus-temperature curves for two alloys Pl and P2 are shown in Fig. I. In each case, the liquid-to-solid transfer has the same composition as the stable solid FIG. I.-GENERAL SOLID SOLUTION DIAGRAM SHOWING S CURVES FOR ALLOYS P1 AND P2. phase only at the temperature of the be-ginning of solidification, and has the same composition as the stable liquid phase only at the temperature of the completion of solidification. At each intermediate tem-perature, the composition of the liquid-to-solid transfer differs by a finite amount from those of the two coexisting phases. Therefore, during equilibrium cooling, the transfers must merge into the solid phase from the liquid without forming a transition phase; otherwise the condition of equilibrium would be violated. At any given temperature during solidification, the composition of the liquid-to-solid

Jan 1, 1940

By A. D. Hughes

C. W. MERRILL*—Mr. Hughes' paper not only is very well presented but is most timely in that it covers a subject of vital interest to the United States. Tin is one of the strategic metals which has not been found here in appreciable quantities. The total United States tin output since the first recorded production over 100 years ago would not supply current consumption for a fortnight. On the consumption side, tin is extremely important in national defense because of its use in tin plate which, in the form of tin cans, makes it possible to feed properly the armies that the United States recruits from its civilian population in emergencies. Moreover, the internal combustion engines so important in powering tanks, planes, and other war machines, require large quantities of tin alloys for bearings and for soldering. These considerations, along with the fact that Malaya, historically, has been the leading source of tin to the United States, make the kind of information that Mr. Hughes has presented so ably. a matter of vital interest. Your Chairman, Mr. Romanowitz, in his introduction, referred to the fact that I had been a member of the United States delegations to the three meetings of the International Tin Study Group. Some cominents on the Group's objectives and deliberations may be of interest. When it appeared that the International Tin Committee, the prewar producer's cartel, might soon revive its operations and extend its control agreement beyond the expiration date of Dec. 31, 1946, the United States Government became interested in some kind of an international trade organization concerned with tin which would give the consumers' interest equal representation with the producers' interests. An international meeting was called in London in October 1946 to consider this problem. I did not attend that meeting hut the result of the meeting was the organization of the International 'Tin Study Group which

Jan 1, 1950

By A. H. Daane, W. J. Wunderlin, B. J. Beaudry

In an earlier study at this laboratory,' the authors investigated the solid solubility of holmium in copper, silver, and gold, and also the melting point of the first eutectic on the noble-metal-rich side in these systems. In a more recent study of the solubility of rare-earth metals in gold at this laboratory. Rider, Gschneidner, and McMasters2 noted that the reported eutectic temperature in the Ho-Au system was lower than the corresponding eutectics in systems of dysprosium and erbium with gold. A redetermination of the eutectic temperature in the Ho-Au system with the same alloy used in the original study showed the eutectic temperature to be 810°C instead of 778°C as originally reported. (The eutectic temperatures in the Ho-Ag and Ho-Cu systems were also redetermined and were found to be 795" and 864°C compared to 787° and 868°C, respectively, which were reported originally.) Since this large change in eutectic temperature made the solubility data appear questionable, new alloys were prepared, heat-treated, and examined metallographically. The procedure of sample preparation and heat treatment used in the original work' was followed except longer heat treatments were used ranging from 7 days at 600°C to 6 hr at 900°C. The results obtained are shown in Fig. 1. There is good agreement between the two studies in the maximum solubility of holmium in gold. Since the slope of the solvus is less pronounced in the present study, the extrapolation to 550°C shows a solubility of 1.6 wt pct Ho in gold compared with 1.0 wt pct in the original work. Since additional data were obtained and longer heat treatments were used in the present study, the larger value is believed to be more accurate. The authors wish to express their appreciation to P. Rider and K. A. Gschneidner. Jr., for bringing this discrepancy to their attention, and also to D. Thompson for assisting in the present study.

Jan 1, 1965

By E. E. Brownson

This paper will be confined to the treatment of methods as applied in the laboratory of the Boston and Montana Reduction Department of the Anaconda Copper Mining Co. at Great Falls, Mont. As the electrolytic plant of this company operates at a current density of approximately 35 to 40 amperes per square foot when running up to capacity, the arsenic and antimony content of the anodes delivered to the plant is of considerable importance as bearing on the purity of the refined cathodes turned out. Owing to the rather high relative percentage of antimony, it has always been the custom to determine antimony as well as arsenic in all forms of copper. Thus, anodes have been analyzed in which the antimony was about equal to the arsenic, although the average shows about 2 parts of arsenic to 1 of antimony. In the refined copper the relative proportions of the two impurities vary considerably, but probably in the average are about equal. In this latter case, the percentage of the two is SO small that ordinarily no attempt is made to separate them, the report of analysis showing percentage of As and Sb combined. Although rapid and exceedingly accurate determinations of arsenic may be made by means of various distillation schemes, the determination of antimony, either by itself or together with arsenic, has always been more or less cumbersome and has required a considerable amount of time. By the methods, details of which follow, the determination of arseluic and antimony, either separated as in the case of anodes or together in case of refined copper, is accomplished in 24 hr. from the time the sample is received by the chemist. As to the accuracy of the results obtained, it can be quite positively stated that in this respect these methods are very satisfactory, much more so than any heretofore employed in our work, and when the rapidity of determination is considered, the results are very accurate.

Jan 1, 1914