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By Oliver Bowles

STRIKING new developments in the field of industrial minerals include the employment of lime, salt, coal, and air for the manufacture of stockings, and the substitution of paper for granite and marble in making tombstones. Certain minerals that have heretofore been regarded as valueless except as museum or laboratory specimens, are now being applied commercially. Serpentine, in forms neither fibrous nor ornamental, massive topaz, pinite, and zoisite are examples. For certain other minerals, notably pyrophyllite, bentonite, vermiculite, and sulphur, extension of established uses into new fields has occurred. Substitution takes a toll in many industries, but producers of industrial minerals as a class have gained more than they have lost in recent years. Encouraging progress has been made in developing at long last a suitable substitute for certain of the uses of mica, the only industrial mineral on the strategic list of commodities established by the War. and Navy Munitions Board. Some of the more important developments in process, equipment, and use .that have come

Jan 1, 1940

By N. J. Sather

A detailed description is given of Bunker Hill's concentration process employed at the company's lead-zinc property in the Coeur d'Alene district, Idaho. The plant is equipped to process 3000 tpd of Pb-Zn ore. The history of the Bunker Hill mine dates back to Aug. 26, 1885, when Noah S. Kellogg found the outcrop of the Bunker Hill orebody on the hillside of Milo Gulch above the present town of Wardner, Idaho. A small concentrator was erected in 1886, and before the railroad came, the mine output was transported by mule teams to the head of navigation on Coeur d'Alene Lake. After ten years of production, an interest was purchased in the Tacoma smelter at Tacoma, Wash., to which the entire output was shipped. In 1916 and 1917, a modern lead smelting plant and refinery was erected, and a modern electrolytic zinc reduction plant was built in 1927-1928 by the Sullivan Mining Co. which was 50 pct owned (and now totally owned) by the Bunker Hill Co. The first concentrator, a 100-tpd capacity plant, was built in 1886 near the Reed Tunnel in Wardner. The treatment consisted simply of crushing ore to 2 in. and then to 1/2 in. through rolls in closed circuit with a bucket elevator and trommel screen. The undersize was further sized in trommels to 10 mm and 3 mm. Oversize from the latter was treated in Hartz jigs. The 3 mm undersize was classified in crude hydraulic classifiers furnishing sands to sand jigs, the overflow being dewatered in a long V tank which supplied sands to a Cornish buddle and to Frue vanners. The concentrates were of excellent grade, old records showing assays of 69 pct lead and 29 oz. of silver per ton. Tailings were high inasmuch as the provision for treating the slimes was inadequate. Since the erection of the first mill, the Bunker Hill plant has gone through many changes and improvements. In succeeding years, the flowsheet was enlarged somewhat with Huntington and Chilean mills, vanners, tables, ball mills, and flotation cells being progressively added. In the transition period to the present day practice, the object was not only to improve the equipment for better mechanical performance, but to add new equipment whenever practicable so as to improve both grade and recovery of the product at a lower cost. For the modern plant and flow-sheet, see Figs. 1 and 2. The history of flotation at Bunker Hill dates back to 1913 when experimental work was done in a cell in which the pulp was circulated through a centrifugal pump set outside the cell and discharged against a baffle in the cell. The cell was built with a spitzkasten, and the quiet zone in the latter tended to let the froth break down before it got to the overflow weir. To remedy this situation, a belt drag with light metal flights was arranged for drawing off the froth over a ramp in each cell. Recovery of lead was not as high as present day practice, but was so much better than the vanners that the cells were multiplied gradually to eight cell units. The mill men called them mud hens. Flow between the cells was controlled by a weir, which determined the pulp level in each cell. These early machines were called Bunker Hill machines. The tailings were later treated in pneumatic scavenger flotation machines in a series, producing concentrates for retreatment in the Bunker Hill cleaners as well as the final tailings. This system of flotation served with minor changes until the Fahrenwald machine was developed at Bunker Hill during the period from 1921 to 1925. In 1925, the Fahrenwald flotation machine gradually replaced the Bunker Hill machine, although the Hearing pneumatic scavengers for retreatment of the tailings from the Fahrenwald machines were retained in the lead section until 1928. The use of the Hearing pneumatic machine for cleaning the rougher concentrates was begun in 1924. In 1941, plans were made for remodeling and modernizing the concentrator, the goal being a modern concentrator employing the latest equipment and milling practices. The old wooden building was to be replaced by a steel and concrete structure. Shortly after preliminary work got under way, the United States entered World War II and the demands for metals increased. To meet this requirement, the management decided to increase the capacity of the concentrator to 1800 tpd. This was accomplished in record time by the construction and operation of a sink-float plant. Installation of this plant was the first step in the general plan for modernization. In 1947 the concentrator (including the sink-float plant) was enlarged to handle 3000 tpd. Milling operations today are at the rate of 2300 tpd, five days per week. During 1959, 453,000 tons of ore was beneficiated. The Bunker Hill concentrator is in three sections: the crushing plant, a 3000-ton capacity storage bin, and the concentrator building. The crushing plant is of wood design with a gunnite coating on the exterior.

Jan 1, 1961

By John Hall

SOME months ago one of the authors was asked to write a paper on the heat treatment of steel castings that would be more comprehensive than other matter lie had published; this is an attempt to present in condensed form the results of experimental work and actual practice carried out for the most part in 1907, 1908; and 1909. It is not a laboratory research and the work done was carried out for the express purpose of putting in practice the processes discovered as fast as possible. Most of the tests are the result of commercial practice and not of bars annealed in our laboratory; most of the micrographs were made for our own records and not for publication. Certain of the micrographs, therefore, are not as clear as we may wish but they were good enough for our purpose at the time they were made. The tests and micrographs are selected from several thousands in our files. All of these micrographs are magnified 60 diameters. These experiments were conducted almost entirely on steel made in a 3-ton bottom-blown converter, and most of the steel illustrated analyzes about 0.05 in phosphorus and sulfur. Unfortunately, a certain number of specimens are shown of which we do not have the complete analysis, but in most cases in which the phosphorus and sulfur vary much from the figure just given that fact is noted. For purposes of comparison, we have included a certain number of micrographs and tests of steel made in the electric furnace, some of which were from specimens made in other shops and some in our own shop, and some tests of acid open-hearth and tropenas steel.

Jan 9, 1919

By Gen-ichi Nakazawa, Masamichi Fujimori, Ichiro Doi

INTRODUCTION The major products of nickel industry in Japan are the electrolytic nickel (E-Ni), the ferro-nickel (Fe-Ni) and the nickel oxide sinter (NOS), totaling in production to 90 - 100 X 103 tons/year in terms of pure nickel content, and sharing approximately 20% for E-Ni, 10% or less for NOS, and the rest for Fe-Ni. The raw materials to be used for these products depend totally upon the imports from abroad; matte, the raw material used in the production of E-Ni, is from Australia and Indonesia; matte for the NOS is from Indonesia and New Caledonia; and garnierite, the raw material for Fe-Ni, is imported in bulk from New Caledonia, Indonesia and the Philippines. This report describes the acquisition of these raw materials, the production processes, trend of supply-demand, problem areas and the measures taken, and so forth, in connection with the nickel industry in Japan. ELECTROLYTIC NICKEL 1. History The nickel industry in Japan began in 1939 by the Sumitomo Metal Mining Co., Ltd. (SMM) with 150 tons E-Ni/month under the blast furnace smelting and the metal anode electrolysis. This was temporarily suspended after the end of last World War II, but resumed in 1952 with garnierite of New Caledonia as a raw material. Since then, the production capacity has been expanded incidentally to the increase of demand. However, since the smelting of garnierite contained about 2% nickel was very costly, the smelting process had been changed to smelt the briquettes of the mixture of garnierite and nickel sulfide concentrate imported from Canada and Australia. In 1975, this smelter was closed, and SMM's nickel refinery used matte from Western Mining Corp. (WMC) of Australia as a raw material. The refining process had been the metal anode one. The crude nickel oxide derived from roasting the high grade nickel matte had been melted and reduced with coke in the electric furnace and cast into anode. In 1970, a new refinery was constructed to produce 1,000 tons Ni/month under the matte anode process, and further, in 1976, the old refinery was converted into the matte anode process, thus resulting in the total production capacity of 1,690 tons Ni/ month today under the matte anode process. Shimura Kako Co., Ltd. began in 1951 to produce a little of E-Ni, and in 1955, they constructed a shaft furnace smelter with New Caledonian garnierite as a raw material to begin the E-Ni production under the matte anode process. Its monthly production reached 400 tons in 1957, but it discontinued its smeltering in 1963 to convert to the matte import from S. Le Nickel, WMC and INCO. In 1979, it changed the source of matte supply from the above to Soroako of Indonesia, discontinued the E-Ni production in 1979, and arranged for a total toll contract with Sumitomo. Meanwhile, SMM has developed a very distingished process for nickel-cobalt separation and refining by a solvent extraction method from nickel and cobalt mixed sulfide generated as a by-product in the nickel recovering process from laterite under the Nicaro process. Nippon Mining Co., Ltd. (NMC) also developed its own process. The plants under these processes were constructed in 1975, with the monthly production capacity of 230 tons of nickel and 130 tons of cobalt by SMM, and 300 tons of nickel and 110 tons of cobalt by NMC. SMM imports the raw material from the Marinduque Mining and Industrial Corp. of the Philippines, while NMC from Queensland Nickel Pty. Ltd. of Australia. 2. Production Status 2.1 Producers and materials Today, SMM holds the monthly E-Ni production capacity of 1,920 tons, of which 1,690 tons are from the matte anode process, and the remaining 230 tons are from the mixed sulfide as a raw material. NMC also uses the mixed sulfide as a raw material for a production of 300 tons/month. [ ] Most of SMM's raw material, nickel matte, is imported from WMC of Australia, partly using the Soroako matte from Indonesia. An example of material analysis is given in Table 1. Matte is a raw material for E-Ni and NOS, and the major sources of matte supply at present are Australian WMC and Indonesian Soroako, occupying ap-

Jan 1, 1982

By S. Norton, S. LeFevre

In the West, capitalists have expended many millions of dollars developing the low-grade porphyry ores of copper. Half a dozen of these great enterprises have proved to be wonderful commercial successes. They have demanded improved crushing and concentrating machinery and consequently it has been developed. Many improved methods, cheap power, superior business organization, all these have contributed to this success, but the main feature is the handling of the material in enormous quantities, on a manufacturing scale. The mining chance of "striking it rich" has been eliminated by the manufacturing certainty of handling large quantities of material of known value, which while of relatively low grade, is available in large tonnages, assuring a supply for many years' run of the mill. Then the returns on the money invested are sure. The concentration of low-grade magnetic iron ores, separating the magnetite crystals from the gangue by the use of magnets, is a field of work in which the lessons taught by the development of the porphyry coppers can be studied to advantage. Large-scale operations, and the liberal expenditure of enough money at the start to insure the most economical operations, are the means of securing the desired results. The problem is to utilize millions of tons, and we may safely say billions of tons, of now worthless iron-bearing rock and to produce from it 10,000,000 to 20,000,000 tons per year of high-grade ore carrying 60 per cent. iron or higher; to take the lean material as found in nature, varying widely in iron content, and bring it up to a uniform standard of shipping ore. At present these ores are mined carrying from 25 to 50 per cent, iron, and the shipping product is brought up to 60 or 65 per cent. Fe. If future economies of operation make it possible to extend this process so that 15 per cent. iron in the crude ore can be treated as a commercial success, the additional tonnage available will be enormous. A 15 per cent. Fe crude ore raised to 60 per cent. Fe concentrate with 5 per cent.

Jan 1, 1917

By Archiblad MacMartin

The Kunigin-Marien-Hiitte is the only works in Germany where the Bessemer process is carried on by the direct method. The Besserner plant there, is arranged after the true English type, and the only resemblance to the Swedish mode of 'procedure is the dispensing with the use of spiegeleisen at the end of the "blow." In a new department of the establishment, started within three years, each of the converters is turned by means of a very neat and compact reversible engine, the steel shaft of which is an endless screw, which turns against the oblique cogs of a large wheel attached to the shaft of the vessel. An advantage which this arrangement possesses over the ordinary English hydraulic arrangement, is the fact that the endless screw suffices to turn the vessel, in either direction, any number of complete revolutions; while even the latest American improvements, so clearly explained to us by Mr. Holley at the opening session of this meeting, do not secure even one complete revolution without changing the angle of inclination of the hydraulic piston. In the endless screw arrangement, there being no limit to the working of the motor in either direction (no return-stroke necessary), the vessel can always, unless outside reasons demand the contrary, be turned around to any desired position by the shortest cut, whether backwards or forwards. Also, the diameter of the cogwheel attached to the vessel can be made sufficiently great to avoid all unevenness of motion. In the old department the motive-power still continues to be hydraulic. If reports be true, the new department produces spiegelized steel, for the manufacture of all-steel rails. But the old department is still, as from the beginning, devoted to the production by the direct method of steel for steel-headed rails. The most remarkable fact connected with this direct steel is the ease with which it welds to the iron 'of the rail-packets, although no borax or other fluxing agent is used to facilitate the welding. It is very rarely that an exception occurs, and an ingot or a charge is discarded by the rail-mill. The mixture of pig-iron used for the production of this steel is melted in cupolas of very interesting construction (not to be de-

By J. Avraamides

Many of the current methods for producing metallic silver particles having specific characteristics involve several steps, are time consuming and subject to contamination. The novel non-aqueous chemistry of silver and copper is used in a simple two step process capable of producing high purity silver powders of specific size and shape. The chemical basis of the process involves the manipulation of the equilibrium -- Cu(I1) + Ag [=]Cu(1) + Ag(1). The addition of at least 50% (V/V) acetonitrile (CH3CN) stabilizes both Cu(1) and Ag(1) ions in aqueous sulphate medium, and the metallic silver dissolves. Removal of the volatile nitrile by distillation reverses the equilibrium and silver powder is precipitated. The nature of the powder depends on the presence of additives such as gelatin, thiourea and polyacrylamide.

Jan 1, 1984

By F. A. Forward, V. N. Mackiw

The paper relates to the laboratory and pilot plant studies that have been carried out by Sherritt Gordon Mines Ltd., Metallurgical Research Div., in developing the ammonia pressure leach process for extracting copper, nickel, cobalt, and sulphur from high grade nickel concentrate produced from Lynn Lake ores, and describes in some detail the chemistry of the process. IT is well known'.' 2 that copper, nickel, cobalt, zinc, ferrous iron, and a number of other metals combine with ammonia in aqueous solution to form complex ions of the form [Me(NH,)x]"+. The stability and solubility of these ions depend on the concentration of the metal ion in solution, on the amount of NH, present, and on the amount and type of anions present, e.g., OH-, C0;-, NO,, C1-, SO;-. If ammonia is partially or completely removed from such solutions, for example by boiling, the soluble ammines tend to decompose and the metals precipitate as basic salts. These properties of metal ammines have found practical application in the commercial recovery of copper, nickel, and cobalt from a variety of ores. In an operation formerly conducted at Kennecott"" the mill tailing containing 0.80 pct Cu as copper carbonate was leached by percolation with an ammonia-ammonium carbonate solution to dissolve the copper as the ammine. At Calumet and Hecla0-" With a mill tailing containing about 0.4 pct Cu as metallic copper, it has been found necessary to aerate the ammonia-ammonium carbonate leach solutions between stages to oxidize the solubilized copper. At Nicarol"-" where nickel and cobalt occur as oxides and silicates which are not soluble in ammonia, the ore is heated to decompose silicates and to selectively reduce the nickel and cobalt to metal, leaving the iron as Fe,O,, and is then leached with ammonia-ammonium carbonate solution accompanied by aeration to dissolve nickel and cobalt as ammines. In each of these leaching operations, the anion present is CO, and the metals can be precipitated from the leach solution as oxide (copper) or hydroxide and carbonate (nickel and cobalt) by boil- ing off NH, and C02 both of which are recycled to treat a subsequent ore charge. The products-—oxide, hydroxide, or carbonate—can be treated by conventional smelting, calcining, or electrolytic methods to convert them to refined metals. Thus the procedures mentioned utilize the properties of the ammines to extract copper, nickel, and cobalt from nonsulphide ores and separate them from the leach solutions. These processes have the advantage that they can be carried out in closed vessels at atmospheric pressure, that the leaching solutions are specific for the desired metals, that the metals can be recovered as relatively pure compounds by the boiling operation, and that the NH, and CO, can be recycled. Also, as the leach solutions after boiling and filtration are substantially free of metals, NH,, and CO,, they can be discarded, thus facilitating the control of the water balance in the leaching circuit. When, as is the case with Sherritt Gordon concentrates, sulphides are treated with ammonia solution in the presence of oxygen, the leach solution contains SO,--, and an entirely different set of conditions is encountered. The ammine sulphates (of nickel, for example) are more soluble than the carbonates and can be only partially decomposed by boiling. The SO, and NH, in the solutions can not be recovered by boiling. Thus, despite the more favorable leaching conditions resulting from high solubility of the ammine sulphates, the recovery of metals, NH,, and SO, from the solutions must be effected by other means. Sherritt Gordon Nickel Concentrate Treatment The Ni-Cu-Co flotation concentrate produced at Lynn Lake'" contains 12 to 16 pct Ni, 1 to 2 pct Cu, 0.2 to 0.5 pct Co, 33 to 40 pct Fe, 28 to 34 pct S, 8 to 20 pct insoluble, and less than 0.02 oz per ton precious metals. The nickel is present chiefly as pentlandite, the copper as chalcopyrite, and the iron as pyrrhotite and pyrite. Most of the cobalt is thought to be present in pentlandite, although it is known that a small amount occurs as Co-Ni-pyrite.

Jan 1, 1956

By H. O. Jahns

This paper describes the application of regression analysis for obtaining a two-dimensional areal description of heterogeneous reservoirs from short-term pressure-time data such as that obtained in interference tests. The method replaces the time-consuming trial-and-error procedure commonly used to match field data on an electric analyzer or digital computer with a systematic search which is programmed for a computer. The computer program adjusts the properties of a reservoir model automatically until a least-squares fit is obtained between observed and calculated pressure data. The reservoir is simulated by a single-phase, compressible, two-dimensional model. It is divided into a number of homogeneous blocks whose transmissibility (kh/F) and storage (Fch) values are varied to obtain the least-squares fit. The reliability of these values is determined from their standard deviations and correlation coefficients. Although the method is rigorously applicable to single-phase flow only, multiphase flow can be handled provided saturation changes are small during the test. Possibly the method can also be used to obtain a reservoir description from pressure-production history, but this application is outside the scope of this work. The paper includes, in addition to a description of the numerical procedure, a discussion of some of the problems associated with the method. Rules are given to help in selecting the number of homogeneous blocks and deciding upon their arrangement. The uniqueness of a reservoir description is considered. Finally, the use of the method is illustrated by the interpretation of field data from two interference tests. INTRODUCTION Pressure data from short-term transient tests, such as single-well and interference tests, are widely used to obtain reservoir properties. These tests are usually analyzed by assuming a simple reservoir model; very often, a homogeneous one is used. As a result, analysis of the transient data from each well frequently gives different values for reservoir properties. The problem then arises to combine all these differing results into a more detailed picture of the reservoir. One technique is to simulate the reservoir with a digital computer or with an electrical analyzer and to adjust the reservoir parameters by trial and error until the simulated pressure data are in reasonable agreement with the observed pressure data for all wells. Although this method has been used for both transient tests and pressure-history data, it is time-consuming and subjective. A second technique uses regression analysis to replace the trial-and-error procedure with a systematic search that can be programmed for a digital computer. Use of regression analysis in reservoir description was proposed recently by Jacquard and Jain.1 They divided the reservoir into a number of homogeneous blocks whose properties are varied until a least-squares fit is obtained between observed and calculated pressures. However, they did not consider their technique to be operational, mainly because of ".. .(I) the lack of experience in using the method .. . notably for the improvement of convergence; and (2) limitations imposed by the insufficiency of available computers". 1 While the analysis presented in this paper applies the same general principle used by Jacquard and Jain, the specific method is significantly different. Some differences are (1) the regression problem is solved in a different way which requires less computer time in most cases; (2) a stepwise solution, in which the detail in the reservoir description is increased from step to step, is used to improve convergence; and (3) the reliability of the estimated reservoir .properties.. as measured by their standard deviation and correlation coefficient, is estimated'

Jan 1, 1967

By Carl J. McHargue

Rods of 99.99 + pct Al which had initial orientatzons of <001>, <118>, <115>, <111>, and random were swaged at room temperature. Changes in orientation as a function of deformation were studied on axis distribution charts. The <001> orientation appeared to be relatively stable due to the inhomogeneity of the deformation process. near the <100> zone were quickly reoriented towards <001>. Orientations on the <110> zone between <118> and <115> appeared to be stable to reductions of about 50 pct, then were reoriented toward <001>. At very high reductzotzs. movement away from the <111> orientation was observed. the requirement that a circular cross section be maintained. In addition to these mechanical factors, there are grain-boundary effects in poly crystalline materials which are not yet understood. Hartmann and Macherauch conclude, for example, that multiple slip occurs for all orientations in fine-grained aluminum and copper and that the choice of operative slip systems has no simple relationship to orientation.? Many investigators have attempted to avoid problems of interpretation caused by an initial texture by treating the starting material to obtain as ran- IT has been generally accepted that the deformation texture obtained at high reductions, e.g. 90 pct, will not be noticeably affected by a prior texture; whereas, that obtained at reductions of 40 to 50 pct may be significantly influenced by the specimen history.&apos; Some recent studies, however, have been interpreted as showing that an initial texture strongly influenced the deformation textures in rods at reductions greater than 90 pct. Freda and Cullity suggested that the <001> texture in a heavily cold-worked copper rod was due to a <001> texture in the original casting. McHargue, Jetter? and Ogle concluded that the <001> component in an aluminum rod extruded at liquid nitrogen temperature was remanent from a <001> texture in the cast extrusion billet.3 Most of the published work on the effect of initial orientation on deformation textures has been for cold-rolled or compressed single crystals,4-6 The primary interest in these studies was to examine various orientations with regard to their stability under flow? thus determining the possibility of such orientations being stable end orientations. There appears to be no published studies on the effect of initial orientation on fiber textures in polycrystalline specimens. A recent study, however, is concerned with the reorientation of individual grains in polycrystalline specimens pulled in tension.? Although the reorientation of single crystals loaded in simple tension is well known, the movements in the forming of wires and rods would be expected to be different due to the circular array of radial-compressive stresses exerted by the die walls or the rolls, and to

Jan 1, 1962

By David B. Brooks, William A. Wallace, James R. Dunn

As the conflict between the mineral industry and preservationists steadily increases, it becomes urgent to determine as precisely as possible the costs of developing vs. not developing our domestic mineral resources so that enlightened mineral policy decisions can be made. A simple discounted cash flow equation is suggested as an approach to assigning a public-interest dollar value to mineral resources. Present value of a piece of land underlain by a mineral resource is taken as equal to the discounted cash flow derived from the resource corrected for present and future surface land values. The equation is effective as a base for mineral aggregate resource planning for metropolitan areas if transportation cost differences are substituted into the cash flow component. Suitably modified, the equation can be fitted readily into an existing computer simulation program for aggregate mineral resource planning in metropolitan areas. However, because of the lack of accurate input, the equation is less effective for other mineral commodities such as base metals and coal. Nevertheless, within a somewhat philosophical context, the equation still has utility and is effective in defining the problem of public interest values for minerals other than mineral aggregates.

Jan 1, 1972

By C. J. Hicks

The labor policy of the Standard Oil Co. (New Jersey) is founded first of all on paying at least the prevailing scale of wages for similar work in the community; on the eight-hour day at the refinery, with time and one-half for overtime; one day&apos;s rest in seven; sanitary and up-to-date working conditions; just treatment assured each employee; opportunity for training and advancement; payment of accident benefits beyond the amount prescribed by the State compensation law; health supervision by a competent medical staff; payment of sickness benefits after one year&apos;s service; coöperation with employees in promoting thrift and better social and housing. conditions; and assurance of a generous annuity at the age of 65, guaranteed for life after 20 years of service. Most of these features have been a part of the company&apos;s policy for many years, but it is only during the past two years that the cooperation of employees in determining these matters has been definitely assured through industrial representation. Industrial representation, in the Standard Oil Co. (N. J.), is a principle rather than a procedure. It is built upon the belief that personal association of those interested in any problem leads to a mutual understanding and a fair decision as to what is right. Fully believing in this principle, representatives of employees and representatives of management evolved a simple plan, the basis of which is that it gives every individual employee representation at joint conferences on problems and fundamental principles affecting all those interested in the industry. It is based on cooperation, not antagonism; its operation makes perfectly clear both to management and to employees that their interests are identical, and not at variance with the interests of the stockholders, and that mutual understanding and cooperation insure progress and success for all. Furthermore, experience has definitely shown that representatives of the employees are not only alert for the employees&apos; interests but are as keen as the representatives of the management in determining and insisting upon fairness to the employer. Though the plan has been in operation nearly two years, it is an experiment, in that, being based on a principle rather than on cut-and-

Jan 1, 1921

By William R. Chedsey

ALTHOUGH few changes can be reported in educational methods at the mineral technology schools during 1940, other events have taken place of direct interest to, and that will have a profound effect upon, mineral industry education on the United States. In the erection of new buildings, some notable changes have been made on the campus, The U.S. Bureau of Mines Experiment Station at the University of Utah, Salt Lake City, was dedicated on May 20. The construction and equipment of this building cost between $300,000 and $400,000. It will be the general headquarters for the metallurgical division of the Bureau and will have a pronounced effect upon the mineral industries research program at the University.

Jan 1, 1941

By Henry Lloyd Smyth

In 1891-92 1 was entrusted with the geological survey of part of the large area lying between the Marquette and Menominee iron-ranges in the Upper Peninsula of Michigan, and extending from the Republic trough on the north, through portions of the valleys of the Michigamme and Fence rivers, to and including the intermediate Felch mountain range on the south. Until a few years back the larger part of this area has been very difficult of access, and much of it is difficult still. The rock-surface is for the most part covered with swamp, forest and glacial deposits of various kinds, and therefore has not invited geological study. For these reasons the district, as a whole, with the exception of the Felch mountain range, remained almost unknown from a geological standpoint until our work in 1892. Our main object was to map the pre-Cambrian rocks, particularly the iron-bearing formations of Algonkian or Huronian age, and to obtain as much information as possible with reference to their sequence and structure, In carrying out this purpose, the use of simple magnetic instruments was found to be of the greatest assistance, and indeed indispensable. In this paper the results of our experience in tracing magnetic rocks by means of the disturbances produced in these instruments, have been brought together in systematic form, with such references to the particular area as are necessary in order to illustrate general principles, with the hope that they will prove useful to other workers in the same region, or in other regions where similar conditions may be encountered. The writer was efficiently aided in the field-work by Messrs. Samuel Sanford and Charlea N. Fairchild for nearly the whole period, and E. B. Mathews and H. F. Phillips for part of it,

Jan 1, 1897

By Zay, Jeffries

THE effect of thoria (ThO2) on grain growth in tungsten was discussed in some detail in a paper presented before this Institute by one, of the authors in 1918.1 In that paper it " was assumed that the, thoria was present in the tungsten entirely as a mechanical mixture. There was no indication in the experiments described that even a trace of the thoria was in solid solution in the tungsten. Langmuir,2 however, observed that thoriated-tungsten filaments under certain conditions showed electron emissions many thousand times greater than unthoriated tungsten at the same temperature. He concluded from his studies that a slight amount of the thoria had dissociated on heating the filament to a temperature near 220°. C. At this temperature and higher, part of the thorium diffuses to the surface of the filament where it evaporates at. a much faster rate relatively, than the tungsten, and also at a rate, nearly as fast as it is brought to the surface by diffusion: If the temperature is lowered to say 1800°,. C., diffusion of the thorium atoms to the surface is more rapid than evaporation, sown adsorbed film of thorium atoms is produced on the surface of the tungsten filament. The electron emission is governed by the outside layer of atoms so the emission from such a filament might be expected to approxi¬mate that of a thorium filament at the same temperature. PRESENCE OF METALLIC THORIUM IN THORIATED TUNGSTEN If the filament containing the adsorbed film of thorium. is heated to a sufficiently high temperature, the thorium atoms evaporate: rapidly and the electron emission becomes more nearly that of tungsten. On cooling again to 1800° C., or thereabouts, the emission &apos;builds up gradually to a maximum. The filament containing the adsorbed layer of thorium atoms is said to be "activated." By studying the rates of activation under different conditions of prior thermal treatment and at different temperatures, Langmuir was able to arrive at an estimate of the

Jan 1, 1927

By John F. Allan

This paper does not pretend to advance any facts or improvements not known to many members of the Institute, but is intended merely to give a few practical hints on preliminary tests, and to call attention to a possible enlarged field for the cyanide process in the treatment of some silver-ores, which merits investigation. Broadly considered, the choice of a process for the treatment of silver-ores in Mexico is confined to the following alternatives: (1) Concentration for treatment by smelting; (2) milling and pan-amalgamation; (3) the patio and Ortega process; [4) chloridizing roast and lixiviation; (5) chloridizing roast and cyaniding; and (6) cyaniding of the crude ore. These methods of treatment may also be combined, and cyaniding or concentration, or both, may be introduced, at what-ever stage it is found to be most advantageous. The characteristics of the ore (especially its gold-content) and local conditions, such as distance from railway, cost of fuel, amount of water available, vary so much that it is impossible to make general comparisons between the different processes, either as to extraction or cost. Concentration and subsequent smelting may be made very expensive by long-distance transportation of concentrates; pan-amalgamation is undoubtedly expensive; and the patio process is barred when the ore contains appreciable amounts of gold, by reason of its poor extraction of that metal; yet there are many ores for which each of these processes is especially adapted, and the expense of treatment is compensated by the results obtained.

Jan 1, 1905

By C. O. Fairchild

ONE of the fundamental principles of efficiency is the use of adequate and permanent records. The rapid increase in the manufacture and use of recording pryometers is a proof of the appreciation of efficiency principles on the part of the manufacturers engaged in the various technical industries. Where recording pyrometers are not employed in an industry in which temperature measurements are necessary, one will generally find that a printed form is used upon which is written, periodically, the temperatures measured by an indicating instrument. It is no serious condemnation of the workman to state that such records are often "doctored," but it is rather a reflection upon the executive who puts such temptation in the way of a workman. One of the well-known "tricks of the trade" is to "force." a furnace so that it will be at the proper temperature during the periodic trips of the foreman or other official. Indicating instruments and recorders may be used together to great advantage. The recorder furnishes .a printed record and a check upon the operator of the furnace, and a record of value in correlating properties of the finished product with the heat treatment. The indicator should be of assistance to the operator in controlling the furnace or oven. Modern practice requires a temperature-recording instrument that is as simple as possible, rugged, reliable, and sufficiently accurate. Of these qualifications reliability is paramount, particularly in cases where the recorder is used for controlling the temperature automatically. By a reliable instrument is meant one that will run continuously with little attention and with a consistent degree of accuracy. That is, if it is in error by 5 per cent. one day, it must be in error by a like amount on any other clay, and not by 2 per cent. or 10 per cent. The earlier forms of recorders were complex and delicate, or mechanically unsatisfactory and inaccurate, and required considerable attention to keep them in operation. Within the past few years, however, the development in the manufacture of temperature recording devices has been highly satisfactory and many excellent instruments are now available. .

Jan 9, 1919

By K. C. Hong, R. B. Jensen

The problem of determining the optimum set of steam volumes and cycle lengths for a single well undergoing multicycle steam stimulation in order to maximize the cumulative discounted net income has been formulated mathematically and programmed for a digital computer. The mathematical fonnulation of the problem and the method for its solution are discussed in this paper. The oil production performance during each stimulation cycle was simulated by either a constant percentage or a harmonic decline. Using simple analytical expressions for production performance, the cumulative discounted net income and cumulative time of operation were related to the pertinent process and cost parameters and two principal process control variables (cycle length and steam injection volume). The discrete maximum principles was used to transform the equations for cumulative time of operation and cumulative discounted net income into a set of simultaneous equations. The simultaneous equations then were solved by trial and error on a digital computer to determine the set of cycle lengths and stem injection volumes that gives maximum cumulative discounted net income over the project life. INTRODUCTION Steam stimulation is a process for improving the oil recovery rate from wells producing high-viscosity crudes. The process is applied on an individual well basis and is executed in a series of cycles, each consisting of three phases: steam injection, soaking (steam condensation), and production. Significant increases in production rate following the stimulation operation result from heating the reservoir around the wellbore. As heat is removed with produced fluids and dissipated into nonproductive formations, the production rate declines, usually to near the prestimulation value. Typical production responses are given in case histories reported by Owens and Suter,l and are depicted in Fig. 1. Duration of the production phase is equal to the time for the oil production rate to decline to some specified value and is called the cycle length. (Cycle length is defined as the producing portion of the cycle and does not include the downtime required for steam injection and soaking operations.) Termination of the production phase coincides with the start of steaming for the next cycle. The process is continued, cycle by cycle, until it becomes unprofitable. Models 2-4 have been developed to simulate behavior of a single well during one cycle of steam stimulation and have been used to investigate the effects of system and operating conditions on the production responses. However, these investigations have not shown how the models can be used to determine a most profitable set of operating conditions for a multicycle stimulation project. Perhaps these models are too complicated mathematically to be adapted readily to an optimization study. This paper presents a method for optimizing a multicycle steam stimulation project based on simple production performance models. First, the performance of a steam-stimulated well during each cycle was simulated by either a constant percentage or a harmonic decline model. Using these simple analytical expressions for production performance, the cumulative discounted net income (before tax) and cumulative time of operation for each cycle were related to the pertinent process and cost parameters and two process control variables—the cycle length and the steam injection volume. Finally, the profit function to be maximized was formed. The analogy between the above problem and problems of optimizing multistage decision processes that have been reported extensively in the chemical engineering literatures5-10 in recent years has led this investigation to the use of the discrete maximum principle.5-7 This principle was used to transform the equations for cumulative discounted net income and cumulative time of operation into a set of simultaneous equations characterizing the optimum operating conditions in terms of the two control variables. These equations

Jan 1, 1970

By C. S. Matthews, J. L. Mahaffey, W. M. Rutherford

This paper gives results of an experimental study of the sweep efficiency of a miscible displacement in a five-spot. The study was carried out in a parallel-plate glass model in which effects of diffusion were scaled at or near the molecular diffusion level. The experiments show that very early breakthrough (25 to 35 per cent of pore volume (PV) injected) may be expected in miscible floods because of the unfavorable viscosity ratio. However after 1 PV of displacing fluid is injected, the sweep rises to a reasonable value (50 to 60 per cent). Photographs show that small slugs of less than 10 per cent of PV tend to dissipate before breakthrough. A minimum slug size of 15 per cent of PV would appear to be necessary even in a relatively homogeneous formation. Presence of a slug whose viscosity is inter-mediate between that of oil and gas increases the sweep efficiency of the oil-gas system. In a typical system the sweep at breakthrough rose from 26 to 37 per cent of PV for a 25 per cent slug. The increase in sweep brought about by use of a large slug could well pay for the extra deferment cost of the additional slug material. INTRODUCTION Most miscible displacement processes involve the displacement of oil with fluids of much lower viscosity and density. The displacement process at these adverse viscosity and density ratios is dominated by instability phenomena, i.e., viscous fingers and gravity tongues. These phenomena have highly adverse effects on oil recovery. Although a number of laboratory studies have been made to determine the effect of adverse viscosity ratios on five-spot sweep patterns,l,2 the scaling of diffusion effects is uncertain. In the series of scaled model studies reported herein, an attempt was made to scale diffusion. Model studies of miscible displacements in which molecular diffusion predominates are per-mitted by controlling the parallel plate spacing which reduces convective mixing to arbitrarily small levels. To decide how this scaling relates to any particular Geld displacement necessitates an estimation of diffusion effects for the natural rock being considered and conditions under which displacement will be conducted. The approach normally taken is to extrapolate data obtained from stable miscible displacements performed in the laboratory, such as those presented by Brigham et al.3 The validity with which such an extrapolation can be applied to an unstable flow system has yet to be established. If this approach is accepted, a family of oil recovery curves can be generated for a single viscosity ratio based on Brigham&apos;s observation that the magnitude of the dispersion coefficient is dependent, among other things, upon specific rock properties. Objective of our test was to define the lower limit of this range by presenting the case where dispersion effects were reduced to the molecular diffusion level in both the transverse and longitudinal directions.

Jan 1, 1967

By W. A. Klikoff, I. Fatt

The concept of fractional wet wattability is examined. Fractional water wettability of a reservoir rock is defined as the fraction of the internal surface urea that is in contact with water. Capillary pressure and relalive permeability of unconsolidated sand are shown to be functions of fractional wettability. INTRODUCTION The petroleum industry has long recognized that wettability of reservoir rock has an important effect on multiphase flow of oil, water and gas through reservoirs. As early as 1928 the American Petroleum Institute sponsored a study of wettability as part of API Project 27 at the U. of Michigan.&apos; Despite 30 years of research, there is still little exact knowledge of the wettability of reservoir rocks. There are two parts to the wettability problem. After agreeing to a uniform nomenclature in regard to wettability,&apos; the first question to be answered is, "What is the in situ wettability of a given reservoir rock?" If this can he answered the next question is, "What part does wettability play in determining the characteristics of multiphase fluid flow through the rock?" This paper represents an oblique attack on the problem of wettability. No attempt is made here to answer the basic question of wettability in situ. instead the consequences of the concept of fractional wettability are examined. Multiphase flow in sandpacks is shown to he highly influenced by fractional wettability. Jennings&apos; has given 3 definition of wettability and the other terms used in discussing wettability. These terms must be applied to the physical situation existing In reservoir rock. A survey of the pertinent literature from 1928 to 1956 indicates that the concept of a contact angle was applied to reservoir rock in the same way it would be applied to a flat, homogeneous surface. Attempts were made to state quantitatively the wettability of a reservoir rock in terms of a contact angle which was presumably constant at all points on the very rough and heterogeneous interior surface of a porous rock. Calhoun, et al,3-6 prepared synthetic consolidated and un-consolidated porous media in which they claimed there was a known uniform contact angle. They then showed the effects on the capillary pressure and relative permeability characteristics of varying this angle. The API Project 47 at the U. of Texas&apos; and others&apos; have made extensive studies of an indirect approach to the contact angle through the use of heat of wetting data. Even if successful. however, this approach also states the wettability of porous rock in terms of a contact angle which is uniform over the entirc surface. If the angle varies from one part to another on the internal surface, there is no way of determining from the measurements the area distribution of contact angles. In 1956 Brown and Fatt5 suggested that the concept of a contact angle, as applied to reservoir rock, be abandoned. This suggestion was made because it is known that the internal surface of most reservoir rocks is composed of many different minerals, cach with a different surface chemistry and a different capacity to adsorh surface active materials from reservoir fluids. Furthermore, the operation of a contact angle in determining the form of a fluid-fluid interface is difficult to picture in the very complex geometry of a pore. Brown and Fatt proposed that the wettability of reservoir rock be stated in terms of the fractional internal surface area that is in contact with water or oil. All surfaces on which there is water are called water-wet; surfaces on which there is oil are called oil-wet. The fractional water wettability is then stated as a number which represents the fraction of the internal surface that is in contact with water. A symmetrical statement can be made for the fractional oil wettability. The concept of a fractional wettability as previously stated has in its favor the recognition of the heterogeneous mineral composition of most reservoir rocks. Another point in its favor is that fractional wettability can be measured quantitatively with relative ease. Hol-brook and Bernard10 se a simple dye adsorption test to obtain fractional wettability of reservoir rocks. Amott11 uses a combination of imbibition and displacement to arrive at a wettability index of reservoir rocks which seems related to fractional wettability in the range 0.25 to 0.75 fractional water wettability. Jennings" has shown the changes in relative permeability that take place when a porous material is changed from unity to zero fractional water wettability. He also shows that reservoir rocks in their natural state, but at room temperature and atmospheric pressure, have relative permeability characteristics which would indi-