Search Documents

By R. E. Phelan

WHILE 1931 was a most important year in the history of Canadian copper smelting and refining, nevertheless, due to the low price of copper and the in- ability of the International Nickel Co. to market its full capacity of nickel. the production of both copper and nickel was considerably less than the total installed capacity for the production of these metals. IIY the nor- mal course of events, 1931 should have seen a great increase in the production. of both copper and nickel in Canada, because the large extensions to both the copper smelting plants and the copper and nickel refinery capacity, which had largely been completed in the year 1930, should be showing their effect.

Jan 1, 1932

By W. H. Blauvelt

THE subject of fuel-briquetting has attracted much attention on the part of engineers and investors for the past 15 or 20 years, and especially in recent years, during which a number of plants have been built, with more or less commercial and technical success. Our technical literature contains numerous descriptions of certain processes, and discussions of the industry in general. For a history of the development of the art in the United States, and for descriptions of many of the processes which have been tried, reference may be made to the files of our Transactions, and, for more recent information, to a paper by C. T. Malcolmson, read before the First Annual Convention of the International Railway Fuel Association in June, 1909. The purpose of the present paper is to describe the briquette-plant of the Solvay Process Co. and the Semet-Solvay Co. at Detroit, Mich., which, after a period of long and costly evolution, is now operating satisfactorily on a commercial basis. I believe that it will be of interest to some of our members to have the details of operation, lower-consumption, labor, etc., as worked out on a practical and commercial scale in a going operation. The briquette industry has had a somewhat checkered career in the United States, and much the larger portion of the failures has been due entirely to commercial causes. It seems axiomatic to say that before undertaking the installation of a plant for manufacturing briquettes it is necessary that the local situation should be carefully examined : First, to determine the kind of briquettes, if any, the local market will consume; that is-to say, whether the available fuel-supply is such that briquettes would be a welcome addition, and whether the most promising field is the industrial or the domestic market. Second, if there is an available supply of raw material, as coal,

Mar 1, 1910

By W. B. Wise, H. D. Attra, W. M. Black

The purpose of this paper is to illustrate a comparatively new approach for solving a problem that has plagued oil producers for many years—how to make the most money with available field production capacity. In a very basic operation such as a top-allowable one-well field, a computer and staff of engineers are not required to determine that the best operation is to produce that well at its maximum for as long a time as it will produce. However, as the problem becomes more complex and the number of wells and number of reservoirs increase, it probably will be a wise choice to devote some engineering thought and calculation time to determine the best way to operate that field on both an ultimate and day-to-day basis. Continued developments in the field broadly referred to as "operations research" have led to a number of useful engineering analyses for optimizing field operational problems. One of these techniques, termed linear programing, is parlicularly interesting because of its potential applications to the study of complex oilfield operating problems. Linear programing is concerned with the problem of planning a complex set of interde~endenl activities in the best possible (optimal) fashion. A field application of linear programing is being used to maximize daily income from a multi-reservoir producing operation. The initial results of this study indicate that the linear programing technique (I) can be applied effectively to field problems, (2) can be used to detect unsuspected avenues for improving operations and (3) can effect a significantly improved means of controlling field operations through the use of the highspeed computer. INTRODUCTION The usual approach for studying complex field operational problems has been to look in detail at several basic plans suggested by judgement and experience and, then, to choose the best plan from those investigated. This approach is entirely satisfactory provided: (1) that judgment and experience alone will reliably pick the best or near the best program as one of the plans to be investigated; and (2), and most important, that the factors which control field production will not change. This paper deals with the large group of field operations which are at least one-step removed from a satisfactory solution using the conventional method of analysis. Problems such as pipeline- and gathering-system design, transportation studies, large field development projects and multi-reservoir producing operations fall in this latter category. To find the best program for handling these problems when the best program is not obvious, a complete optimization study is required, and high-speed computers are required to continually update the program once it is selected. Operations of this type have an extremely large number of possible solutions. However, only one will result in maximum economic return and, more important, this one program must be re-evaluated and adjusted constantly to accomodate such changing field factors as the number of producing days, the price of crude, the discovery of new reserves, declining reservoir pressure with subsequent decline in production and a host of other factors which characterize specific operations. One of the most widely used, direct methods of optimization is a numerical procedure termed "linear programing", which is designed to investigate systematically each of the possible solutions involved in a given problem, determining rapidly and uniquely the optimum answer. As implied by the name, linear programing requires that all field variables be either defined or expressed in a series of interdependent linear equalities or inequalities. These relationships are solved simultaneously, using a form of matrix solutions to determine the optimum values for each producing variable that will maximize net profits. The solution techniques used in a recent field case study is termed the "simplex method" and is discussed in full detail in Ref. 1.

By N. I. Fisher, J. Shepherd

A rapid method of determining natural fracture trends in collieries has been developed. The method will yield information that is precise enough to permit fracture domain boundaries to be delineated in a coal seam. Instead of a survey of cleat trends in a colliery taking several man-weeks or even man-months, a reconnaissance survey can be carried out in only a few man-days. At each of a sequence of sampling sites along a traverse, five measurements of trend are recorded for each set of fracture directions. A sequential plot of the medians of each fracture set is then made manually underground or by a computer in the mine office. Changes in fracture pattern can be detected easily in colliery development work if a geologist visits advancing faces regularly, and forecasts can be made about the likelihood of forthcoming faults and dykes. A full description of this method is given in Shepherd and Fisher (1981). The concept of mapping fractures rapidly in a colliery is based on using a geological traverse (Compton, 1962), along which observations can be made at chosen, regular intervals. The technique has been widely used for surface mapping across outcrops and in follow-up work in photogeological studies (Hepworth and Kennerley, 1970). In these cases, the geologist surveys the traverse line as mapping proceeds. In a colliery, however, ready-made traverse lines already exist in panels and along main roadways, often in several directions. It is thus possible to traverse a colliery in different directions and record the fracture trends at intervals, generating a reconnaissance fracture map. This can also be done on a continuing basis as mine development takes place. Generally, a sampling traverse should be longer than 0.5 km with sampling sites at relatively close-spaced intervals along the traverse. For example, in room-and-pillar mines pillars are commonly formed on 40-m centers and the sampling sites can then be arranged at 20-m intervals [(Fig. 1)]. The sites might have to be closer together for mines known to have bad mining conditions. The predominant fracture trend is normally the face cleat and the subordinate trend is the butt cleat (McCulloch et al.. 1974). Various changes can occur in the cleat or joint pattern: the face and butt sets may disappear or an entirely new set or sets may appear. Therefore, it is best to record all prominent fracture sets. Sometimes there is only one; in other cases there may be as many as three or more. An odd number of measurements of each fracture set are made (generally five or more) to enable the median value to be determined easily. The median value can be plotted underground using graph paper or a computer plot can be made in the laboratory or mine office [(Fig. 2)]. The sequential linked median (SLIME) plot draws the median trend for each sampling site as a unit line segment. The segments from successive sampling sites can be connected together to form a long chain [(Fig. 2A)]. The needle plot, on the other hand, draws a straight line to represent the traverse and then plots out the median trend for each sampling site [(Fig. 2B)]. The SLIME plot is better for visual display, as it highlights small irregularities and gross changes in trend. However, some work is required to relate the individual segments to their site location along a traverse. In this respect, the needle plot is more convenient because each segment -can be plotted-at a point corresponding to its location. Also, there is precise match-up if needle plots of face and butt cleat are compared. A description and listing of the SLIME program is given by White et al. (1981). An example of the use of this method is given for Wallsend Borehole colliery in New South Wales (Australia) [(Fig. 2)], where domains II and IV are associated with mining hazards. Domain II is coincident with a normal fault of 2.6-m throw, and domain IV with a basic dyke 12 m thick. These hazards were approached driving in a southwesterly direction, and a pronounced change in trend of the cleat to a northwesterly direction occurred at a distance of approximately 45 m from each one. The northwestern joint trend is parallel to that of the dyke and fault, and it occurs at a higher frequency close to these structures. The association of a particular joint set with faults has been found elsewhere (Shepherd and Creasey, 1979). The two minor cleat direction changes within domain V are narrow joint zones that are less than 5 m wide. The fracture trends derived from a SLIME traverse can be verified by collecting larger quantities of data at selected sites, as shown in the balloon density (rose) plots depicted in [Fig. 2C]. We are grateful for the financial support provided by Thiess Bros. Pty. Ltd. and the National Energy Research, Development, and Demonstration Program administered by the Commonwealth Department of National Development and Energy. R.W. Miller Holdings Ltd. and Thiess Bros. Pty. Ltd. are thanked for their permission to publish data from their collieries.

Jan 1, 1982

By Jack Washburn, E. R. Parker

Kinking in zinc single-crystal tension specimens was observed under conditions of low stress and high temperature. Kinking is discussed in relation to other plastic bending phenomena on the basis of dislocation theory. Experiments on the stress-induced motion of small angle boundaries are reported. KINKING was first reported by Orowan1 as a new deformation mechanism. He observed the phenomenon in cadmium single crystals loaded in compression. Glide lamellae in a local region of the rod were observed to snap over suddenly to a tilted position, resulting in a sudden shortening of the specimen. Between the tilted portion and the rest of the crystal there were fairly sharp boundaries, with the slip plane assuming approximately mirror image positions on opposite sides of these boundaries. Orowan considered the boundaries to be regions where dislocations had concentrated. Hess and Barrett' observed the formation of kinks in critically oriented zinc compression specimens. It was found that the sudden snapping over of the tilted region was not an essential part of the kinking phenomenon but rather was associated with the method of loading. Kinking was explained on the basis of the accepted mechanisms of slip and flexural glide. It was also suggested that a kink can be considered as a special type of deformation band. During a recent investigation of the effect of surface condition on creep of zinc single crystals," a similar phenomenon was observed in crystals which were loaded in tension. The specimens were 0.4 in. diam cylindrical rods with a free length of 4 in. between end connections. All of the crystals were tested at a constant load. adjusted to give an extension rate of approximately 0.05 pct per hr. Kinking, as shown in Fig. 1, occurred in some of the tests performed at temperatures above 200°C. Kinking was observed in specimens varying widely in initial orientation, scattering about a 45" angle between the slip plane and the specimen axis. The condition leading to kinking in tension appeared to be non-uniform distribution of flow along the gage length combined with the restraint imposed by the tensile load. At low temperatures and fast strain rates, the distribution of strain throughout the midsection of tension specimens was generally quite uniform; therefore, bend planes developed only near the ends as described by Miller.4 However, at high temperatures under creep conditions it was difficult to obtain specimens in which the distribution of flow was uniform. Some of the factors which may have caused differences in flow stress along the length of the crystals are: Nonuniform distribution of impurities, accidents of growth (lineage structure), slight bending or other damage during handling, surface conditions, and strain-aging characteristics due to dissolved nitrogen." Plastic flow, once started in a local region, often continued to a relatively large strain before other parts of the gage length became active. Under these conditions a series of kinks, such as those in Fig. 1, were produced. Fig. 2 illustrates how a nonuniform distribution of slip produces bending moments which- are responsible for kink formation. If no plastic bending were to occur while the rod extended by pure slip in two separate sections of the rod, it would assume a shape such as that in Fig. 2a. A specimen having this shape and being subjected to a tension load would have concentrations of stress at the concave surfaces C and lower than average stress would exist at the convex surfaces D. Therefore a bending moment is superimposed on the average stress in the regions between C and D. The positions of potential bend planes under these conditions are shown as dotted lines. Actually no such shape as Fig. 2a develops because plastic bending in the region C-D occurs simultaneously with pure slip in the intervening regions. The observed structure of a tension kink is indicated by Fig. 2b. Perhaps the best approach to an understanding of kinking as well as other related plastic bending phenomena, such as the bend planes discussed by Miller,' cell formation studied by Wood et al.,6 and polygonization,7 is consideration of the dislocation model of a bent lattice. Current theories of the slip process postulate generation or multiplication of dislocations at certain lattice imperfections. The mechanism proposed by Frank and Read8 results in continuous generation of concentric dislocation loops which spread out

Jan 1, 1953

THE CHAIRMAN (G. H. CLEVENGER, Stanford University, Cal.).¬I would like to ask Mr. Pyne if he has had any experience inn the use of chromite as refractory under conditions that are highly reducing? I am reminded of an experience I once had with an electric furnace. I imagined that chromite would form a splendid lining, but it soon disappeared; hence it seems probable that, under highly reducing conditions at a high temperature, chromite is a very poor refractory. F. R. PYNE.-In copper smelting the atmosphere is generally neutral, or slightly oxidizing; we do not use highly reducing atmospheres at all, not even in the matting furnace. You can take the chromite brick and treat it as you would an iron ore, obtaining ferro-chrome very readily, from which the copper will separate. We have done this; in fact, at one time we considered installing a small electric furnace for the production of ferro-chrome. FOREST RUTHERFORD, New York, N. Y.-During the time I was general superintendent at the smelter of the Copper Queen Consolidated Mining Co., at Douglas, Ariz., a great many experiments were made on the furnaces and settlers with different kinds of brick, and I agree with Mr. Pyne's statements about chrome brick. Their power to absorb metals is very great, and as they cannot be smelted at any temperatures obtainable in a copper furnace, to get rid of the bats and extract the metal from them is quite a problem. We finally got down to using chrome brick only for lining the settlers, out of which we often got a life of upwards of 2 years, and for lining the blast-furnace bottoms, for the reason that chrome brick can be heated and wet, or wet after being heated, without going to pieces, whereas under these conditions magnesite brick will break down very rapidly. We also used a layer of chrome brick above and below an 18-in. band of magnesite brick put on the slag line of the reverberatories, in order to separate the magnesite from the silica brick, fearing that they would slag each other and let the wall drop. The idea worked, but became unnecessary on account of a change made in the method of feeding the furnaces. Chronic brick will not stand up under pressure so well as a good Grecian or Austrian magnesite brick, on account of the poorer bonding properties of the materials from which the chrome brick is made.

Jan 4, 1918

By E. R. Shorey

FLOTATION-Mill operator's have recognized that slimes are detri-mental to the flotation concentration of zinc ores. The, presence of primary slime in many of the Wisconsin ores is largely responsible for the failures experienced in treating these ores by flotation. These failures have discouraged the adoption-of the flotation process by opera-tors in the Wisconsin zinc district. The removal of slimes by decantation seemed to be the obvious way to meet the problem of treating slimy or' clayey ores by flotation. To facilitate the removal of slime, it was decided to mix the ore pulp with sodium silicate, which acts to deflocculate the pulp.1 Deflocculation causes slime suspension, making it possible to separate the slime from the sands by decantation.2 Since the literature contains little definite information on the use of sodium silicate to deflocculate ore pulps, a series of tests was conducted to obtain the necessary information. Tests to determine the settling rates of sand and slime in deflocculated pulps were conducted on a dolomite-marcasite-sphalerite ore ground to minus 80 mesh (175 microns) and mixed with water to form a pulp. The deflocculator3 was Mallinckrodt 40° to 42.5° Bé. liquid sodium silicate (Na20 + 3.25Si02). .By microscopic analysis the suspended slimes4 were found to be minus 15 microns (approximately 1000 mesh).

Jan 1, 1934

By Charles M. Means

A thoroughly modern coal-handling system has been installed at the Pittsburgh Terminal H. H. &. Coal Co.'s new No. 8 shaft, or Cover-dale mine, about 11 mi. (17.7 km.) from Pittsburgh on a spur of the Montour R. R. The Pittsburgh scam, which is the one worked, is reached at a depth of 342 ft. (104 m.). Power is delivered to the mine at 22,000 volts over a transmission line of the bow-arrow type of construction. A private telephone line connecting the various mines and the main office in Pittsburgh is carried on the same poles. The high-tension line is brought to an outdoor, step-down, transformer substation, where three 833-kv.-a., single-phase, 60-cycle, oil-insulated, self-cooled transformers reduce the potential to 2300 volts. The transformers are protected by electrolytic, aluminum-cell lightning arresters, horn gaps, and choke coils. High and low-tension busses, together with fuses, choke coils and air-break horn-gap switches with thcir remote-control operating mechanism are mounted on a substantial structural-steel tower 25 ft. (7.6 m.) in height. Mine Substation The transformer substation is adjacent to a. pressed-brick building that houses direct-current substation equipment together with switchboards, etc., for the control and distribution of power. This building also contains the hoist for the men and supplies. Main Switchboard The 2300-volt circuit is carried underground in a conduit from the transformer substation to an oil switch in the substation and supply hoist building. This is the main switch controlling the 2300-volt busbars mounted back to a twelve-panel black-slate switchboard. From the switchboard, 2300-volt circuits are carried to transformers feeding the street and house lighting systems and to other transformers furnishing power for the elevator and lighting circuits in the store building. Other 2300-volt circuits run from this switchboard to the main hoist building, fan house and auxiliary or man-and-supply hoist. High-tension wiring,

Jan 1, 1922

By B. C. Burgess

AFTER many years of close and friendly association with talc and soap-stone, this orthographically distinguished mineral steps forth in this edition, for the first time in a chapter of its own. Pyr, the Greek for fire, and phyllite, a rock or stone, form its name and at the same time refer to the first recorded use of pyrophyllite as firestones or hearthstones. Another derivation of "phyllite" is from the Greek phyllites, "of leaves," alluding to the beautiful white radial crystal aggregates that form when pyrophyllite is heated. Pyrophyllite used by the Chinese for carving is called agalmatolite, from the Greek agolma, meaning an image. COMPOSITION AND PROPERTIES Pyrophyllite has previously been grouped with talc because of the close similarity of the minerals in physical and optical properties. They have the same space group; and chemically they are closely related, pyrophyllite being the aluminum silicate A12Si4010(OH)2 and talc the magnesium silicate Mg3Si4010 (OH) 2. Another arrangement of the pyrophyllite formula is generally given as A12034Si02H20 because it expresses the chemical composition as usually determined (alumina 28.3 pct, silica 66.7 pct, water 5.0 pct). Vanderbilt gives pH values of pyrophyllite 5.6 to 8.4.29 Pyrophyllite usually is white, pale green, cream or pale yellow, buff or light gray. It is found in darker shades and other colors principally due to oxidation of contained iron minerals. It is translucent in thin sections. In hardness it is 1 to 2 in the Mohs scale. Its specific gravity is 2.8 to 2.9. In bulk specific gravity, the powdered mineral ranges from 0.4 to 0.7. Its luster is pearly to dull; it is infusible in the Bunsen burner flame, slightly affected by aqueous solutions of sodium carbonate and hydrochloric acid. It is decomposed by sulphuric acid, with separation of gelatinous silica. It is characterized chiefly by its micaceous structure and cleavage, its softness and greasy feel. Two other varieties occur

Jan 1, 1949

By D. D. Pollock, G. P. Conard II

Equations of the form of the Mott and Jones equations for the absolute thermoelectric powers of metals are derived primarily from a thermodynamic approach. The behaviors of transition thermoelements in common use are then examined and compared with this simple theory. MOTT and ones' derived a general expression for the absolute thermoelectric behavior of metals and alloys using the approach of the solid state physicist. This expression was then applied to specific cases.1,2 The present work develops equations of the same form principally by a thermodynamic approach. These relationships are then employed to gain some insight to the behavior of the transition thermoelements in common use. I) DERIVATION OF AN EXPRESSION FOR ABSOLUTE THERMOELECTRIC POWER First consider a metallic conductor which is maintained in a temperature gradient with no current flowing. At constant pressure, there will be a gradient of the free energy (F,) given by:

Jan 1, 1963

By B. S. Butler

AN understanding of mineralizing solutions and how they carry and deposit metals is of prime importance to students of ore deposits. Lindgren states: "The whole problem surely is very complicated. One difficulty is that we know so little about the stability field of ore minerals."1 Lindgren further states: It is believed that they [the solutions] were in small part oxidized to sulphates, for instance, but in large part they were composed of hydrogen sulphide, alkaline sulphides and various halogen compounds. Doubtless, however, free carbon dioxide was present. Becker's view of the double sulphides as important constituents of the solutions probably holds good. In the fourth edition of Mineral Deposits2 Lindgren had changed his views somewhat: From the work of Day, Allen, Shepard, and others, it would seem probable that many of the volcanic gases are acid when given off but are in unstable equilibrium, and could not have preserved this acid character after having been long in contact with the surrounding rocks. It is believed that they were in small part oxidized to sulphates, for instance, but in larger part they were composed of hydrogen sulphides, alkaline sulphide, and various halogen compounds. Doubtless, however, free carbon dioxide was present. Becker's view of double alkaline sulphides as important constituents of the solution probably holds good. The writer wonders if progress would not result from an attack on the problem in steps, the steps to contribute to the attack on the whole. The initial step would deal with the simpler bodies of supposed magmatic (hydrothermal) origin, that is, those composed essentially of silicates, oxides, sulfates, and sulfides. The following discussion attempts to develop one step of a method that was proposed on a more comprehensive scale in 1929 by the writer and W. S. Burbank.3 The accompanying partial table (Table I) of the electromotive series is from a table distributed by Merck & Co. Inc., manufacturing chemists, prepared in turn from Fundamental Chemistry.& The electromotive arrangement brings together elements that in hypogene ore deposits occur: 1) in oxygen combination only; 2) in combination with sulfur as well as with oxygen; and 3) as sulfides, arsenides etc., and as native metals, see Table 11. The writer clearly recognizes that he is not qualified to discuss the formation of ore deposits as a chemical problem, but he feel that some of the relations that are met by the geologist can well be stated with the hope that the chemical explanation will be forthcoming. By consideration of a group including mainly the elements oxygen, hydrogen, sulfur and iron, complications are avoided, especially with elements of the lower electromotive group. The results can only contribute to the solution of the problem, not to the completion of it. The pH and Eh of the solutions and also temperature probably determine what minerals form. The mineral groups that contain elements high in the electromotive series are alumino-silicates, titanites, simple silicates, spinels, oxides, carbonates and sulfates, in all of which the elements are combined with oxygen. These groups are also recognized as the general order of temperature at which the minerals start to form, see Table 11. At low temperature are sulfides, arsenides, antimonides, sulfo-salts, and native metals, in all of which the elements are characteristically not combined with oxygen. The intermediate temperature group contains elements that form both oxygen compounds and sulfur compounds.

Jan 1, 1957

By J. A. Rowland, C. W. Funk

THIS investigation is a part of the United States Bureau of Mines work in conserving the Nation's resources. The isothermal sections presented were developed as a guide to a comprehensive investigation of the properties and fabricating characteristics of copper-base alloys containing manganese and tin. These alloys are being investigated as possible replacements for the commercial bronzes containing substantial quantities of tin. Development of the isothermal sections has, therefore, been limited to the area between 0 to 20 pct Mn and 0 to 25 pct Sn. Since Heusler1 reported the ferromagnetic properties of the Cu-Mn-Sn alloys in 1903, the system has been the subject of several investigations. These studies were largely concerned with correlation of magnetic properties and crystal structure.2-6 Vero,' however, established the solidus surface of the system, between 20 pct Mn and 40 pct Sn, by thermal and microscopic methods. The a, ß, and y solid solutions were also observed by Vero and reported to extend into the interior of the ternary system. For the present study, the annotated diagram of the Cu-Sn system prepared by Raynor' and the Cu-Mn diagram by Dean and coworkers9 were used as the binary borders of the ternary system. Procedure The metals used in this investigation were electrolytic manganese, washed cathode copper, and three-star tin. The manganese, produced at the Boulder City pilot plant of the Bureau of Mines, had a purity of 99.9 pct; the copper contained less than 0.004 pct Bi and 0.001 pct S; the tin contained 0.070 pct Pb, 0.070 pct Sb, 0.050 pct Fe, and 0.065 pct Si. Heats of 1 lb were melted in alundum crucibles with a 3-kw induction furnace. The heats were chill-cast in iron or copper molds to form 6-in. ingots 3/4 in. in diameter. Molds were washed with graphite or zirconia, depending on the manganese content, and preheated to 150°C. The maximum impurity content of any alloy was 0.03 pct Fe, 0.02 pct Si, and 0.02 pct Al; in most cases, they contained less than half this quantity of any of these impurities. Composition of the alloys and their treatment prior to homogenizing are shown in Fig. 1. Designations adjacent to each composition refer to the heat numbers. With a few exceptions, ingots containing 20 pct Sn or less were hot-swaged. These ingots were swaged, after a 24-hr preheat at 650°C, to obtain a total reduction of 70 pct in cross section. Intermittent reheating was necessary, and reductions were limited to either 0.025 or 0.050 in. in diameter per pass. Selection of a 200-hr homogenizing treatment was based on extensive experiments which indicated that virtual equilibrium was reached after 150 hr. Structures were retained by quenching in water. Grain sizes in the specimens homogenized at 350" and 450°C were generally small. These homogenizing treatments were preceded by a 50-hr anneal at 650°C to facilitate phase identification by increasing the grain size in these specimens. The specimens were furnace-cooled from this temperature to the homogenizing temperature, and the heat treatment was continued for the standard 200-hr period. The homogenized samples were bisected to provide an internal section for metallographic examination. Optimum definition of the microstructure was obtained by successive polishing and etching. Quarter-strength ASTM copper reagent No. 13 gave the most satisfactory results.10 Filings from interior sections of the samples were used for diffraction studies. These filings were annealed in evacuated glass tubes at homogenizing temperatures for periods exceeding 50 hr and quenched in water. During this treatment the manganese content was reduced by significant amounts, probably by vaporization. This change in composition was considered in applying the diffraction data, which were used only as a means of identifying phases where the data were consistent with the metallographic evidence. Phase Identification The a solid solution is readily distinguished by the copper-colored, twinned, polyhedral grains, as shown in Fig. 2, and a face-centered cubic X-ray pattern. Tukon indentations, using a 25-g load, indicate a Knoop hardness of 155 for a quenched from 650°C. Using white light developed by a Wratten 78 A filter, the ß grains in etched specimens have a dark brown tint in contrast to the lighter copper-colored grains of the a phase. Knoop hardness values of 284 were obtained for the ß structure in specimens quenched from 650°C. The ß structure was also distinguished from the a phase by its body-centered cubic lattice. The acicular structure appearing in Fig. 3 was evident in several alloys of higher tin content after quenching from either 750' or 650°C. Since a trans-

Jan 1, 1954

The following list of corrections has been compiled from the thirty-five volumes, with some additions: VOLUME I. Page 160. The first two sentences of the second paragraph should read as follows : " For No. II we find that 2.33 percent. A1,08 take 4.07 per cent. 8109, leaving 3.48 per cent. 8102 free, which requires 3.25 per cent. CaO." Page 160, line 14, 3.79 should be 3.25; and in the 15th and 18th lines, 48.44 should be 46.98. VOLUME VI. Page 59. The discharges of the miners' inch per second, given as .2624 and .2499 cubic feet, should be .02624 and .02499, respectively. The discharges per minute, hour, etc., are correctly given. VOLUME VIII. Page 214. 16th and 25th lines, ferric carbonate should be ferrous carbonate. Page 486, 16th line, 10,000 should be 5,000. [ ]

Jan 1, 1907

By Ernest Burchard

FLUORSPAR is found in most of the states from the Rocky Mountains westward, and commercial production of the mineral has been reported from Arizona, Colorado, Nevada, New Mexico, Utah and Washington. The map in Fig. 1 indicates the general distribution of many of these deposits but it is by no means complete. In the summer of 1926 the writer examined certain deposits of fluor-spar in Arizona, California, Colorado, New Mexico and Washington; in November, 1927, revisited the Jamestown, Colo., district, and in earlier years examined deposits in Colorado and New Mexico. Based on notes of his own and. on descriptions and other data by H. A. Aurand, H. W. Davis, R. B. Ladoo, V. C. Heikes, W. D. Johnston, Jr., and by producers of fluorspar, he prepared the following brief descriptions of deposits and estimates of reserves of fluorspar, originally for the use of the subcommittee on fluorspar of the Joint Committee on Foreign and Domestic Mining Policy and on Industrial Preparedness respectively of the Mining and Metallurgical Society of America and the American Institute of Mining and Metallurgical Engineers. Descriptions of many fluorspar deposits in various western states and districts have been published. It is not feasible to summarize this literature here, but the appended bibliography will indicate to the interested reader what papers are available.

Jan 1, 1933

The opening session of the Institute was held at the rooms of the American Society of Civil Engineers, No. 4 East 23d Street, VicePresident R. W. Raymond in the chair. After a short introductory address by the chairman, the following names were presented by the Council for election as members and associates of the Institute. They were unanimously elected : MEMBERS. Abbott, James W.,.....Lake City, Col. Abbott, J. J., Jr.,...... Lake City, Col. Bartlett, J. C.,.....Cambridge, Mass. Billings, G. H.,.....Boston, Mass. Blake, Frank C.,.....Lafayette College, Easton, Pa. Dewey, Fred. P.,.....Lafayette College, Easton, Pa. Douglass, Samuel T.,. .. . Ann Arbor, Mich. Emmons, 9. F.,.....New York City. Engle, George U.,.....Philadelphia. Harrington, Dr. Bernard J.,. .. Montreal, Canada. Hayden, Wm. B.,.....Columbus, O. Hill, Leslie C.,.....Capelton, Quebec, Canada. Land, W. J.,......Atlanta, Ga. May, Wm. A.,.....Scranton, Pa. Mills, James E.,.....St. Louis, Mo. Moore, Charles W.,.... Montezuma, Ind. Page, William Byrd,.... Lexington, Ky. Putnam, Douglas, Jr.,.... Ashland, Ky. Richards, Henry,.....Dover, N. J. Boberts, Percival, Jr.,. .. . Philadelphia. Sackett, S. G.,......Brooklyn, N. Y. Schley, Wm. S.,.....Atlanta, Ga. Setz, Gustav,......Mine La Motte, Mo. Talhutt, John H.,.....Lexington, Ky. Torrey, Herbert G.,.... U. S. Assay Office, New York City. Wernlitz, Fred. W.,..., Cartersville, Bartow Co., Ga. Wiestling, Geo. B.,.....Mont Alto, Franklin Go., Pa.

THE opening session of the Institute was held at the rooms of the American Society of Civil Engineers, No. 4 East 23d Street, Vice-President R. W. Raymond in the chair. After a short introductory address by the chairman, the following names were presented by the Council for election as members and associates of the Institute. They were unanimously elected : MEMBERS. Abbott, James W., - Lake City, Col. Abbott, J. J., Jr., - Lake City, Col. Bartlett, J. C., - Cambridge, Mass. Billings, G. H., - Boston, Mass. Blake, Frank C., - Lafayette College, Easton, Pa. Dewey, Fred. P., - Lafayette College, Easton, Pa. Douglass, Samuel T., - Ann Arbor, Mich. Emmons, S. F., - New York City. Engle, George U., - Philadelphia. Harrington, Dr. Bernard J., - Montreal, Canada. Hayden, Wm. B., - Columbus, O. Hill, Leslie C., - Capelton, Quebec, Canada. Land, W. J., - Atlanta, Ga. May, Wm. A., - Scranton, Pa. Mills, James E., - St. Louis, Mo. Moore, Charles W., - Montezuma, Ind. Page, William Byrd, - Lexington, Ky. Putnam, Douglas, Jr., - Ashland, Ky. Richards, Henry, - Dover, N. J. Roberts, Percival, Jr., - Philadelphia. Sackett, S. G., - Brooklyn, N. Y. Schley, Wm. S., - Atlanta, Ga. Setz, Gustav, - Mine La Motte, Mo. Talbutt, John H., - Lexington, Ky. Torrey, Herbert G., - U. S. Assay Office, New York City. Wernlitz, Fred. W., - Cartersville, Bartow Co., Ga. Wiestling, Geo. B., - Mont Alto, Franklin Co., Pa.

Jan 1, 1877

By John D. Hanks

INTRODUCTION Chevron's Uranium Mill is located near Panna Maria, Texas; 70 miles southeast of San Antonio. Designed by Kaiser Engineering, the Mill will process a nominal 2500 dry T.P.D. of uranium bearing ore containing 15% uncombined moisture. Earl Torgerson, San Mateo, California, is the consulting metallurgist on process design. Feed to the plant consists of a mixture of high, medium and low grade sandy day ore; the average grade of the ore will be 0.7% throughout the life of the project. The ore is delivered to the mill via truck and stored by type in individual piles on a flat storage area. The ore is fed by conveyor to a semi-autogenous grinding mill. The SAG mill discharge slurry is pumped either to a storage tank or to the first of five mechanically agitated leach tanks where both H2SO and NaC103 are added. Following leaching, the slurry is mixed with thickener No. 2 overflow before being pumped to a six-thickener, countercurrent decantation circuit where the solution containing uranium is separated from the leach residue. The residue is washed essentially free of solubilized U308 values at the sixth thickener and discharged to an adjacent tailings pond. The first thickener overflow, containing approximately 0.4 grams U308 per liter, is filtered for clarification and sent to the liquid ion exchange (solvent extraction) section. The pregnant aqueous solution is mixed with organic solvent containing amine on which the complex uranyl sulfate ions are absorbed. The immiscible aqueous and organic solutions are mixed and separated in each of the four stages of solvent extraction. The final pregnant organic is directed to a stripping section. A strip solution containing (NH4)2S04 (ammonium sulfate) and NH4C1 (ammonium chloride) is contacted and separated from the organic in each of the four mixer-settler units. The strip solution is mixed with NH3 and the uranium precipitates along with trace amounts of sulfate, chloride, and ammonia. After washing in a thickener, the uranium precipitate or yellowcake is centrifuged and dried in a multiple hearth roaster. Overflow from the yellowcake thickener is recycled back to the stripping section of the solvent extraction circuit. The dried yellowcake concentrate contains more than 98% U308; diluents include H20, ammonia, chloride, etc.. Impurity concentratons in the product are sufficiently low, after drying, to permit direct shipment to refinement installations. ORE RECEIVING Ore from one or more mines will be stored on a pad adjacent to the uranium processing mill. Ore stored in the area may total 200,000 tons or more, which is equivalent to over a two month treatment reserve for the mill. In addition to providing surge capacity, the proposed storage facility permits natural oxidation of the ore and affords an area which, in turn, improve plant U308 recovery and reduces consumption of oxidizing reagents. The uranium bearing ore is segregated at the storage area into several distinct types. One group can be identified by its sandy, clay-like matrix and will be distinguished by its U308 concentration of high, medium, or low. Other ores contain substantial quantities of carbonaceous shale, typical of ore in the area. Feed is recovered from any one or combination of piles, in accordance with operating requirements and recovery factors. The run-of-mine ore, at 15% moisture, is transferred to a stationary, 24-inch by 24-inch grizzly. Undersize material falls into a 280-ton surge hopper located below grade, while oversize material is removed for preliminary size reduction. A sump-pump is located at the reclaim hopper to recover excess mositure and ore spillage for processing. Plant feed is continuously drawn from beneath the hopper at an average rate of 120 tons per hour by means of an apron feeder. The hopper is equipped with a low level safety system to protect the apron feeder assemble. The ore is transferred to a belt conveyor, elevated and discharged into a semi-autogeneous grinding (SAG) mill. Water addition at the discharge point is automatically controlled by a feed rate, moisture analyzer system located on the belt conveyor. GRINDING Minus 24-inch ore, at a rate of 120 mosit tons per hour and cyclone underflow at a rate of 137 moist tons per hour are combined with a controlled 186 gallons per minute fresh, warm plant process water. The mixture, at an average 68% solids, is fed to the SAG mill. The viscous mass is subjected to grinding at a temperature moderately above ambient resulting from use of the 140ºF well water. The 16.5'x5.0' Marcy Mill is driven by a 500 H.P. A.C. Motor. The mill will rotate at 73.4% of critical speed or 14.06 R.P.M. Eight percent of the mill's volume will be occupied by steel grinding balls; 22% by pulp. The mill is designed to rotate in either direction, in order to obtain maximum lifter and liner life. The SAG mill is equipped with a trommel having ½ -inch slots for removal of oversize material at its discharge and the large or oversize material is collected and either recirculated periodically or discarded. The undersize slurry is diluted to 64% solids with the addition of hot well water or mine water to the mill discharge sump. The flow is automatically controlled utilizing data from a gamma density meter. The slurry from the mill discharge sump is pumped to hydrocyclones to classify the particles. Underflow from the cyclones, at 80% + 28 mesh, is recycled to

Jan 1, 1979

By James Douglas

IN discussing the waste upon which hinges, or is supposed to hinge, so largely the preservation of our national resources, the conclusions reached would be more reliable if actual ex¬perience were consulted, and fewer deductions were drawn from general statements, which are often the product of the imagination. It cannot be questioned that the value of by-products has not been sufficiently appreciated by us, and that our, tardiness in recovering the useful ingredients of the escaping gas of our coke-ovens is one of the most glaring instances of shortcoming in that direction. And yet even for that sin there is some palliation in the immature condition of affiliated industries. I presume that it is admitted, without argument, that, except under very exceptional conditions, all the elements cannot be recovered from most of the ores or natural products. which we treat. While it is a shame that the by-products from our coke-ovens should be dissipated, Edward W. Parker's report to the U. S. Geological Survey for 1906' supplies a fairly good excuse in justification of this appalling waste. He says (pp. 773 to 774.)

May 1, 1909

By Frederic Benard

PRIOR to 1936, the Ontario Refining Co. received all incoming blister copper from The International Nickel Company's smelter in the usual form of 460-lb. cakes, or slabs. These were received in open cars in lots of 250 pieces. At the refinery the cakes were unloaded onto narrow-gauge cars, for convenient handling and pickup by charging cranes. In March 1936, an investigation was started on the feasibility of trans-ferring converter copper in the molten state from the smelter to the refinery anode furnaces, a distance of 114 miles. Although common in steel practice, the transportation of blister copper in this form had not previously been attempted and a preliminary study of the various factors involved was therefore necessary. For this purpose, a series of experiments was made in which molten copper, removed at different stages during the furnace cycle, was held in a small portable holding furnace. This vessel was essentially a refractory-lined steel cylinder provided with ports for filling and emptying, heated by an oil burner. Dimensions of the steel shell were 3 ft. 10 in. diameter by 7 ft. 3 in. long, and thickness of refractories depended oil the design and combination used for the particular experiment. The vessel was filled with approximately 2 ½ tons of copper at a predetermined temperature, the lining having been preheated to a definite point by means of an oil burner. All openings were well luted and temperature readings were made every 15 min. by means of an immersion-type thermocouple. In this manner the rate of heat loss resulting with different refractory design could be developed. The ratio of exterior surface to weight of metal was taken into consideration in comparing the experimental results with what might be expected for a full-sized unit, and observations were also made on type and degree of slag accretion. It was not possible to get as much information on this latter point as desirable, but all evidence showed that the problem would be control of slag build-up rather than attack oil refractories.

Jan 1, 1938

By DIFTIGIHT E. WOODBRIDGE

(Glen Summit Meeting, June, 1911,) DURING April, May, and June, 1910, I was in charge of an examination of the greater part of the Moa iron-ore area in Oriente Province, Cuba, on the north coast, near the east end of the island. My instructions, on arrival at the properties, were to check former estimates of tonnages and grades, and to re-examine the ore comprised in claims covering 44,727 acres. This work included .the running of lines dividing the properties into co-ordinate planes, the boring of many thousand feet of holes spaced at the intersections of these co-ordinates, the taking of samples of the ore penetrated, the analysis of these samples for their various constituent minerals, and the determination of the results as to tonnages, depths, and grades, both for individual properties and for the entire group. Each section of every one of the thousand holes drilled was to be compensated for depth and grade with every other, a series of simple arithmetical calculations of no slight magnitude, the mere mechanical labor of which consumed much time, but finally resulted in giving a complete average of all the essential facts for the entire area of 18,000 hectares. Had it not been for the more than willing, active, and able co-operation of the officers of the Spanish-American Iron Co., from Charles F. Rand, President, and Jennings S. Cox, General Manager, down to the most humble water-carrier, the work would have consumed far more time than it did. Papers prepared by others, and to which my present paper may be considered an addendum, elucidate, more fully than I could hope to do, the origin and geological character of these ores. I will confine myself to the situation, method and expense of exploration, and to probable courses of development and mining, with some attention to the cost of the ore delivered in the United States.

Mar 1, 1911