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By E. K. Landis

The question of magnetic concentration is assuming considerable importance, and the efficiency of the different concentrating-machines is widely discussed. As the amount of iron left in the tails must vary with commercial requirements, and with the nature of the minerals in the tails, the writer feels justified in calling attention to some points often overlooked. In almost every such commercial operation a point is reached beyond which it does not pay to go, the material saved by further operations being obtained at a cost too great. The amount of iron left in the tails from concentration must depend, therefore, upon the cost of crushing, the size to which the ore is crushed, the nature of the minerals in the gangue, and the nature of the ore itself. Some ores are so intimately mixed with their gangue that a large loss of iron in the tails is unavoidable. In many cases the gangue contains hornblende, pyroxene, serpentine, etc., which carry considerable iron as silicate, or otherwise combined, and this iron a magnetic machine cannot extract, since the minerals themselves are not magnetic. It is evidently unfair to charge the machine with this loss of iron; and hence a satisfactory test of any such apparatus would require that the iron present in the ore as magnetite should be determined, and the proportion in the tailings of such iron only should be the measure of the loss, as compared with theoretical efficiency.

Jan 1, 1892

"In the spring of 1927, six members of the American Institute of Mining and Metallurgical Engineers met for dinner at the Chemists' Club in New York to discuss the possibility of setting up a committee within the Institute to further the current interest in the science of steelmaking. Attention to this subject had been crystallized by a symposium held by the Faraday Society in 1925. After a prolonged discussion, ranging from thermodynamics to slag conditioning, it was decided to approach the Institute with the request that a standing committee on "The Physical Chemistry of Steel Making" be set up. This committee proposed to promote scientific and practical papers on the subject, and was designed to cooperate with the Open Hearth Committee of the Institute in bringing scientific developments to the attention of open-hearth operators throughout the country. . . . "As the life of the [Physical Chemistry of Steelmaking] Committee lengthened and general interest in the technical phases of steelmaking grew, it .became evident that there was a distinct need for a book that might serve the open-hearth interests to better advantage than standard texts whose scope is necessarily wide and whose detailed exposition of the open-hearth process is, therefore, somewhat limited. With this thought in mind, the Committee, after some years of consideration and debate, embarked on the venture of writing a manuscript on 'Basic Open Hearth Steelmaking'." The foregoing paragraphs, taken from the introduction by C. H. Herty, Jr. to the first edition, well describe the circum- stances which led to the publication of “Basic Open Hearth Steelmaking” in the spring of 1944. The book consisted of nine- teen chapters contributed by twenty-three authors and edited by the staff of Alloys of Iron Research and T. S. Washburn, H; M. Larsen, and J. S. Marsh with Frank T. Sisco as consulting editor. The Engineering Foundation and the Open Hearth Steel Committee of the Iron and Steel Division, AIME, made financial grants; steel companies and other organizations supported the publication by contributing time and expenses of staff members in their capacity as authors or editors. The volume was sponsored by the Seeley W. Mudd Memorial Fund and appeared under the

Jan 1, 1964

By S. G. Lasky

W E seem to have assumed the careless habit in recent years of treating mining geology as synonymous with exploration geology, and exploration synonymous with exploration for new deposits-to be forgetting that mining geology includes also the geologic control or guidance of day-by-day mining operation. In the publicized romantic spotlight of the search for new deposits, we forget the man with the dirty over-alls, grubbing away at the daily tasks of finding new shoots and of helping to keep production up and cost down. During 1949, as in previous years, the resident geologist continued his quiet efficient functioning while the exploration geologist continued to stay in the spotlight-although this time he shared it with what may be called the resource-appraisal geologist. Many broad problems of national import such as tax modification, the operations of the Economic Cooperation Administration, and certain international relations have come up against an unexpected factor lurking in the background, namely, appraisal of world and domestic reserves and latent resources. T. M. Broderick opened the year with his address as retiring president of the Society of Economic Geologists, wherein he analyzed the problems of exploration geology listing among them "the shortcomings of the geologists themselves, of the educators, the mining companies, our Published by permission of the Director, U. S. Geological Survey. technical publications, the Federal Survey and Bureau of Mines, and the property owners."

Jan 1, 1950

"In the spring of 1927, six members of the American Institute of Mining and Metallurgical Engineers met for dinner at the Chemists' Club in New York to discuss the possibility of setting up a committee within the Institute to further the current interest in the science of steelmaking. Attention' to this subject had been crystallized by a symposium held by the Faraday Society in 1925. ' After a prolonged discussion, ranging from thermodynamics to slag conditioning, it was decided to approach the Institute with the request that a standing committee on "The Physical Chemistry of Steel Making" be set up. This committee proposed to promote scientific and practical papers on the subject, and was designed to cooperate with the Open Hearth Committee of the Institute in bringing scientific developments to the attention of open-hearth operators throughout the country... . "As the life of the [Physical Chemistry of Steelmaking] Committee lengthened and general interest in the technical phases of steelmaking grew, it became evident that there was a distinct need for a book that might serve the open-hearth interests to better advantage than standard texts whose scope is necessarily wide and whose detailed exposition of the open-hearth process is, therefore, somewhat limited. With this thought in mind, the Committee, after some years of consideration and debate, embarked on the venture of writing a manuscript on `Basic Open Hearth Steelmaking'." The foregoing paragraphs, taken from the introduction by C. H. Herty, Jr. to the first edition, well describe the circumstances which led to the publication of "Basic Open Hearth Steelmaking" in the spring of 1944. The book consisted of nineteen chapters contributed by twenty-three authors and edited by the staff of Alloys of Iron Research and T. S. Washburn, B. M. Larsen, and J. S. Marsh with Frank T. Sisco as consulting editor. The Engineering Foundation and the Open Hearth Steel Committee of the Iron and Steel Division, AIME, made financial grants; steel companies and other organizations supported the publication by contributing time and expenses of staff members in their capacity as authors or editors. The volume was sponsored by the Seeley W. Mudd Memorial Fund and appeared under the

Jan 1, 1951

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Jan 1, 1907

THE paper on "Specific Efficiency of the Blast Furnace" by Richard Franchot, which was pub-lished in the September issue of MINING AND METALLURGY, was presented for discussion at the Pitts-burgh meeting. The session opened with a discussion among S. P. Kinney, Mr. Franchot, and J. N. Reese as to the methods and results in sampling for cyanides in the blast furnace. This is covered in detail in writ-ten discussion below. T. T. Read objected to the use of the term specific efficiency as likely to be confusing. The blast furnace has to perform the function of reducing Fe, 03 to Fe as well as that of fusing the metal and, since the reduc-tion of Fe, 0? involves a CO equilibrium, it seems mis-leading to calculate efficiency on the basis of burning the , all carbon to CO? since it is not possible. Mr. Franchot replied that he used the term in the sense defined by Richards in his "Metallurgical Calculations;" but a subsequent search failed to reveal the term in Richards, who says (page 245, 1st edition): The practical conclusion is that a blast furnace generates in itself not much over 40 per cent of the calorific power of the fuel used, and rejects nearly 60 per cent; by using part of the waste gases to heat the blast, however, some of this rejected heat, to an amount representing net 5 to 10 per cent of the calorific power of the fuel used, is returned to and injected bodily into the furnace, thus rendering available for the purpose of running the furnace about 50 per cent of the calorific power of the fuel as a maximum. The efficiency with which the furnace applies this 50 per cent usefully to the objects of the reducing and smelting is another question for investigation.

Jan 2, 1927

By K. Koneko, T. Nokoyama, S. Shibato

SEYBOLT et al.' have detected various silica films formed on a 3 pct Si-Fe alloy after heating at low oxygen potentials with the electron diffraction method, and they have made some observations on the H,0/H2 ratios required to form them. The purpose of this note is to describe the structure of the oxide film formed on either mechanically or electrolytically polished surfaces of a 3 pct Si-Fe alloy containing small amounts of manganese after heating at low oxygen potential. The samples were prepared from a Si-Fe alloy made in the laboratory using electrolytic iron, 76 pct ferrosilicon, and 76 pct ferromanganese, vacuum-in-

Jan 1, 1969

By Will Mitchell, Ford F. Miskell, C. L. Sollenberger

THE taconites in general are hard, tough ores, difficult to grind. Liberation of iron mineral constituents usually is accomplished by grinding the ore through at least 100 mesh, and often it has been found necessary to grind substantially through 325 mesh to achieve satisfactory recovery and grade in the concentration process. Because of the fineness of grind required and the enormous tonnages of material contemplated for treatment in the future, costs resulting from grinding media wear and power consumption, together with capital investment required for comminution, approach astronomical figures. Economy in any one of these elements per ton of material ground could very well reflect a considerable saving to the ferrous industry in yearly costs. With this in mind, the Research Laboratories of Allis-Chalmers Manufacturing Co. have launched a program to discover means of effecting this economy. The initial phase of the work as described here deals with a heat treatment of crushed raw ore, followed by thermal shock in cooling, for the preparation of rod mill feed. Several investigators 1-5 have noted an improvement in the grindabilities of ores treated in this manner. One investigator2 subjected low grade iron ores to heat treatment in an electric furnace. Basing his conclusions on screen analyses of crushed products, he observed that treated ore was more easily crushed than the untreated. He reported that observation of the treated and untreated ore through a microscope revealed cracks following the grain boundaries in treated ore, whereas no cracks were present in untreated ore. However, few if any have quantified the improvement in terms of total hp hours saved, reduction of wear of grinding media, or reduction of capital costs of grinding equipment involved. By means of Bond rod mill and ball mill grindabilities6 and by comparative wear tests, the conditions maintained during this investigation have been definitely evaluated. Heat treatment experiments have been made on a batch scale in a muffle furnace, followed by continuous scale experiments in a rotary kiln under various conditions of temperature, atmosphere, retention time, and quenching to determine the combination that would give the greatest improvement in the grindability of a taconite without affecting adversely the magnetic susceptibility of the magnetite. From these data, relative costs have been calculated for grinding both untreated and heat treated ore on a basis of plant capacity of 120 tons per hour. Heat requirements for a rotary kiln, as well as the kiln capacity required for the treatment, have been estimated. For these tests 50 tons of ore were obtained from the Aurora mine of the Erie Mining Co., Hibbing, Minn. The ore was reported' to have been selected from the magnetic portion of the lower chert horizons. An average chemical analysis of this portion is shown in Table I and an approximate mineralogical analysis is shown in Table II. No attempt was made to differentiate between the various silicates because the compositions vary widely on the different horizons and depend on the degree of oxidation. Minnesotite, however, is the predominant silicate. The siderite grains were dispersed throughout the ore but were essentially associated with the rock-forming minerals. In a series of preliminary tests in which batches of -6 mesh ore were heat-treated in a muffle fur-

Jan 1, 1952

By C. A. Heberlein

INTRODUCTION THE present war in Europe seems to have stimulated the demand for quicksilver. In July last, the price ranged around $35 per flask of 75 lb., while to-day it seems to fluctuate between $47.50 and $50. The use of quicksilver in the form of fulminate, containing 70 per cent., and as corrosive sublimate, containing 73.8 per cent., must be extensive and a further market advance may be expected. With such an advance, some revival in quicksilver mining maybe looked for, particularly in California, where many abandoned properties exist. What can be done with low-grade quicksilver ores under favorable conditions, particularly with low mining cost, may be seen from the following description of the Oceanic mine, near. San Luis Obispo, Cal. Its operations date back to 1876, when rich sand ores were discovered. In three years 7,400 flasks of quick-silver were produced, but since then the deposit has been only sporadically worked. Until two years ago various attempts had been made by the Oceanic Quicksilver Co. to mine the more refractory "mud rock," which was encountered lying beyond the "sand rock." Mud and sand rock in varying quantities were treated together with poor results, but operations were successful with sand rock of fair percentage. About two years ago,, when all the sand rock had been exhausted, Murray Innes purchased the Oceanic mine. He found large quantities of low-grade mud rock, varying from 6 to 8 lb. of quicksilver per ton, which at the prevailing low price of quick-silver demanded very cheap mining costs, in conjunction with high but cheap metallurgical extraction. At that time the extraction of quicksilver from mud rock ranged between 40 and 50 per cent., as far as I am able to, learn.

Jan 2, 1915

By J. H. Westbrook

IT is always of interest to document the origin of real microstructures which closely approach various idealized morphologies. Such instances constitute excellent bases for experimental studies of the effect of microstructure on properties. Typical examples include the eutectoid steels (lamellae) used by many investigators and the two phase Cu-Cr alloys (spheres) recently employed by Hibbard and Hart The present note describes a structure with cylindrical particles. In a study of certain alloys in the Cr-C system, an alloy was arc melted whose composition was very close to the aCr-Cr,C, eutectic (3.2 wt pct C, according to the latest phase diagram published by Bloom and Grant2). The alloy was not analyzed but previous experience with the melting technique employed indicates good correspondence between intended and analyzed compositions with negligible tungsten contamination from the electrode. The phases present in the alloy were identified by X-ray powder patterns as a chromium and Cr,C,. Typical micrographs, presented in Fig. 1, show unmistakable evidence of the cylindrical geometry of the carbide phase. The eutectic grains are randomly oriented and, consequently, only a few show the true fibrous nature of the carbide particles, most being cut so as to show slightly elliptical cross sections. Within any particular grain, remarkable uniformity is to be observed with respect to the size, shape, spacing, and orientation of the carbide particles. Length to diameter ratios have been estimated from the micrographs to be at least 250:1, with diameters of about lp. This alloy may be of further interest from different viewpoints. On the one hand, it might be used to check the applicability of the equations derived by Fullman3 for computing true particle dimensions of cylindrical particles from opaque random sections. On the other hand, it might be possible to extract the carbide particles from this alloy and repack them in a ductile matrix to form a synthetic structure of the type discussed by Metcalfe et al.4 With the large l:d ratio and the small diameter of the carbide fibers, it is likely that the interdefect distance in each fiber is sufficiently great to permit realization of a large fraction of the presumed high strength of the carbide. References 1W. R. Hibbard, Jr. and E. W. Hart: Dispersion Hardening of Copper-Chromium Alloys. AIME Trans., 1955, vol. 203, p. 200; Joun-nal of Metals, January 1955. 2D. S. Bloom and N. J. Grant: The System Chromium-Carbon. AIME Trans.. 1950. vol. 188. p. 41; JouRnal of Metals, January 1950. aR. L. Fullman: Measurement of Approximately Cylindrical Particles in Ooaaue Samples. AIME Trans.. 1953, vol. 197, p. 1267; Journal of Metals. ~ebtember 1953 4 A. G. Metcalfe, C. H. Sump, and W. C. Troy: Fiber Metallurgy. Metal Progress, 1955, vol. 67, p. 81.

Jan 1, 1958

By Peter Tegart

The discovery of gold in the Toodoggone River area is credited to Charles McClair who mined placer deposits in 1925, reportedly valued at $17,500. After he and his partner went missing in 1927, efforts to relocate their workings resulted in the formation of Two Brothers Valley Gold Mines Ltd. in 1933, in which the legendary Grant McConachie (first president of CP Air) played an active role. This was the age when the prospector first utilized the airplane to reconnoitre remote areas. What greeted the observer from the air was an area rich in orange and yellow colours characteristic of gossans formed by the oxidation of sulphides. However, Samuel Black, a Hudson Bay Company fur trader, had also noted in his diary as early as 1824, the unusual and many gossanous colours in the headwaters of the Finlay River. These gossans, coupled with white limestone bluffs and the presence of placer gold, attracted the first reconnaissance of the area by Cominco in 1929. Cominco was ever active in remote areas at this time. They staked and worked several base-metal showings hosted by limestone at the margins of intrusive stocks. These early workers also obtained erratic high gold assays from chalcedony float samples found in creeks draining into the Toodoggone River. However, because the samples gave inconsistent assays, no concerted effort was made to locate their source. Except for the occasional horse-supported prospecting party of the late 1940s and early 1950s, the area did not receive much attention until 1968. Work until this time focused on the base metal lead-zinc showings which contained attractive silver credits. Gold was not an attraction because of the set price established by the US government. The late 1960s saw the northward expansion of porphyry copper exploration into the Toodoggone. A program of gossan soil sampling (gossans which had attracted the early workers) was carried out by Kennco Explorations (Western) Ltd. in 1966-1967. They analysed for base metals in the field, using a cold extraction method. The Kemess copper- gold prospect was staked as a result of anomalous copper values from this early geochemical program. In 1968, Kennco continued the program of silt traversing and field geochemical testing. The samples were further subjected to multielement analysis consisting of copper, molybdenum, lead, zinc, cobalt, nickel, and silver at Kennco's North Vancouver laboratory. Several anomalous creeks, high in combinations of copper, molybdenum, and silver, were outlined. Some initial soil grids were also established. The fall of 1969 saw the return of Kennco prospector Gordon Davies and geologist Bob Stevenson to check out a well-defined molybdenum, scattered copper and silver anomaly in soils from a grid on the Chappelle claims. The subsequent analysis of several selected quartz felsenmeer floats yielded one assay which ran in the order of 0.25 kg/t (8 oz per st) gold and 2.2 kg/t (70 oz per st) silver. Subsequent trenching on the Chappelle claims exposed the source of float in a 4- m (134) wide vein of high grade gold-silver mineralization. These results led quickly to the realization that the district had precious metal potential. Subsequent exploration in the period 1969-1974 by Kennco resulted in the discovery of most of the gold and silver occurrences on the Chappelle and Lawyers properties. Several other gold and silver occurrences were found in this district by Cordilleran, Cominco, and Sumitomo, working the district during this period. Conwest optioned the Chappelle in 1973 and explored underground by adit entry as part of a one-year program. In 1974, Du Pont of Canada Exploration Ltd. optioned the Chappelle claims and in March 1980, using reserves developed on the A vein, placed the Baker mine into production at a rate of 90.7 Vd (100 stpd). The Amethyst zone on the Lawyers property, 8 km (5 miles) north of Chappelle, was found in 1973 by Kennco using continued, persistent followup prospecting of silver silt geochemical anomalies. A silt anomaly in the order of 3.4 ppm silver occurred in a stream flowing 300 m (984 ft)

Jan 1, 1985

By A. R. Gregory

A shear wave velocity laboratory apparatus and techniques for testing rock samples under simulated subsurface conditions have been developed. In the apparatus, two electromechanical transducers operating in the frequency range 0.5 to 5.0 megahertz (MHz: megacycles per second) are mounted in contact with each end of the sample. Liquid-solid interfaces of Drakeol-aluminum are used as mode converters. In the generator transducer, there is total mode conversion from P-wave energy to plain S-wave energy. S-wave energy is converted back to P-wave energy in the motor transducer. Similar transducers without mode converters are used to measure P-wave velocities. The apparatus is designed for testing rock samples under axial or uniform loading in the pressure range 0 to 12,000 psi. The transducers have certain advantages over those used by King, 1 and the measurement techniques are influenced less by subjective elements than other methods previously reported. An electronic counter-timer having a resolution of 10 nanoseconds measures the transit time of ultrasonic pulses through the sample; elastic wave velocities of most homogeneous materials can be measured with errors of less than 1 percent. 5- and P-wave velocity measurements on Bandera sandstone and Solenholen limestone are reported for the axial pressure range 0 to 6,000 psi and for the uniform pressure range 0 to 10,000 psi. The influence of liquid pore saturants on P- and S-wave velocity is investigated and found to be in broad agreement with Biot's theory. In specific areas, the measurements do not conform to theory. Velocities of samples measured under axial and uniform loading are compared and, in general, velocities measured under uniform stress are higher than those measured under axial stress. Liquid pore fluids cause increases in Poisson's ratio and the bulk modulus but reduce the rigidity modulus, Young's modulus and the bulk compressibility. INTRODUCTION Ultrasonic pulse methods for measuring the shear wave velocity of rock samples in the laboratory have been gradually improved during the last few years. Early experimental pulse techniques reported by Hughes et al.2 and by Gregory 3 were beset by uncertainties in determining the first arrival of the shear wave (S-wave) energy. Much of this ambiguity was caused by the multiple modes propagated by piezoelectric crystals and by boundary conversions in the rock specimens. Shear wave velocity data obtained from the critical angle method, described by Schneider and Burton4 and used later by King and Fate sand by Gregory, 3,6 are of limited accuracy, and interpreting results is too complicated for routine laboratory work. The mode conversion method described by Jamieson and Hoskins7 was recently used by King 1 for measuring the S-wave velocities of dry and liquid-saturated rock samples. Glass-air interfaces acted as mode converters in the apparatus, and much of the compressional (P-wave) energy apparently was eliminated from the desired pure shear mode. A more detailed discussion of the current status of laboratory pulse methods applied to geological specimens is given in a review by Simmons.8 A new shear wave velocity laboratory apparatus has been developed for testing rock samples under elevated pressures. This apparatus employs liquid-solid interfaces as mode converters. The technique for generating pure shear waves at liquid-solid interfaces was developed from studies of critical angle methods.6 Two identical transducers are placed in contact with opposite ends of the rock sample, one transducer acting as an ultrasonic energy emitter or generator and the other acting as an ultrasonic energy receiver or motor. The P-wave energy emitted from the piezoelectric crystal in the generator transducer is converted into pure S-wave energy at the Drakeol-aluminum

By G. P. Sewell

Callow-Type flotation cells, with various modifications, have been employed at the Hayden concentrator since 1917. Other flotation machines, such as matless-air and mechanically agitated types, which have been tested in competition, have failed to handle tonnages or give metallurgical results equal to the modified Callow-type cells on the Ray ores. The original type consisted of wide, deep launders with a relatively flat bottom constructed of porous concrete, through which the air was introduced into the flotation pulp. These cells were constructed to handle the tailings from the gravity concentrating process and no special attention was given to pre- conditioning the pulp ahead of flotation.

Nov 1, 1955

By J. S. Marsh

OPPORTUNITY to pay tribute to the memory of Professor Henry Marion Howe is a strenuous assignment as well as an honor. Upon recalling Howe lecturers and lectures of the past 25 years, glancing over the list of those earlier, and rereading Howe's books, I arrive at several conclusions: 1—Many lecturers either worked under or knew Professor Howe. 2—It is virtually impossible to pick a subject on which Professor Howe did not touch. 3—There is precedent for a technical paper based upon pursuit of a single subject. 4—There have been listening lectures and reading lectures. There is solid comfort only in 2: the subject field is wide open. I did not know, nor even ever saw, Professor Howe, so can supply no fitting reminiscence. As a college student I was dimly aware that he counted among the giants. Fuller appreciation of his stature came with reading his books and papers, growing acquaintance with some of his associates, and the intrinsic dignity of the climax of the Annual Meeting, beginning at four o'clock of a Thursday afternoon in the auditorium of the Engineering Societies Building in New York. As for producing the technical paper sort of thing, it is my lot to have reached an age and assignment such that to do so would be to filch information from those who did the work and whose story is theirs to tell; for this I have no enthusiasm. As for the final conclusion, Professor Howe was one of the chosen few so highly expert at expository writing that he could produce a lecture or paper that reads as though it would also have listened well. One of his tricks was the free use of words not ordinarily part of the technical vocabulary, provided that such words were likely to communicate most precisely what he had in mind. How wonderful it would be for all who must read reports by the ton if ability at exposition could be taught with the effectiveness open, say to, differential calculus! Perhaps Professor Howe should be required college reading even if for no other reason than to prove that technical writing need be neither dull nor diffuse. My assignment is clearly still strenuous. Another point to consider is the fact that metallurgy is now so tremendously diversified that hope of finding a topic of universal appeal is negligible, even if one were competent enough to be permitted free choice. That which follows is, therefore, a compromise composed of necessity and of the obligation to attempt to avoid boring to slumber those of you who are not especially interested in the general subject chosen. The Iron and Steel Div. is now essentially a process metallurgy division, heavily concerned with the smelting of iron and the making of steel. The American Iron and Steel Inst. figure for present steel capacity of this country is 125,828,310 net tons; how this is divided among processes is indicated by the production totals for 1953, shown in Table I. The glamor girls and boys make the front page and so it is with steelmaking processes. If there is an Antarctic Daily Bugle, it undoubtedly has carried stories of revolutionary development, such as oxygen processes and vacuum melting, and stories of the incomparably rosy destiny of electric arc melting. All such certainly have their place and their future; meanwhile, it is the sturdy and old reliable open hearth that accounts for the bulk of production reported back on the financial page, and it is the old reliable that is most likely to continue to account for the bulk for some perfectly sound raw material, technologic, and economic reasons. This, plus the fact that next year marks a centennial (for it was in 1856 that Frederick and William Siemens conceived the regenerative open hearth), is reason enough to talk about open hearth furnaces, but is not the real one. The real reason is that in some years of association with open hearths, I have accumulated—in addition to a genuine liking and respect for them—certain odds and ends of fact and fancy that this lecture provides a unique chance

Jan 1, 1956

By Lars Rossemyr, Terkel Rosenqvist

The equilibrium Mn + 2 IiCl = MnCl2(g) + H2 has been studied at 1090°C for pure manganese and for Mn-Si alloys. For this reoction a standard free energy of Fo1363, = - 19,700 i 300 col ioas found. Combined with other thermal data, the standard free energy of the reaction Mn(s, ß) + Cl2 = MnCl2(g) was derived: Fo=- 56,140 + 9.78 T log T - 40.10 T For the formation of the various manganese silicides the following free energies were obtained. 5 Mn + 3 Si - M1z5Si3 ?F°1363 = -41,500 i 1500 cal Mn + Si - h.lnSi ?F°1363= -10,000 i 500 cnl Mn + 2 Si = MnSiz ?F°1363= -11,500 ± 500 cal In the search for a method suitable for the study of thermodynamic properties of certain alloy systems, it was found that the heterogeneous equilibrium between the alloy and a gas mixture consisting of hydrogen chloride, hydrogen, and volatile metal chlorides has considerable advantages. In addition to giving thermodynamic information about the alloys, such measurements may be used to derive thermodynamic data for the volatile metal chloride itself. The present paper gives some results which were obtained for manganese silicides and manganous chloride. Similar studies are presently being carried out for the iron silicides. The phase diagram of the Mn-Si system is rather well known,' but no information exists to the authors' knowledge about the thermodynamic properties of manganese silicides or about the chemical activities in molten Mn-Si alloys. At elevated temperature, manganese may react with hydrogen chloride according to the equation: Mn(s, ß ) + 2 HC1 = MnC1, (g ) + H2 [ 1] with the equilibrium constant The value of K, may be determined from measurements of the gas composition in equilibrium with pure manganese. When this value is used in connection with measurements on manganese alloys, the chemical activity of manganese in the alloy may be derived. Initial calculations showed that around 1000" to 1200°C the equilibrium constant K1 has a value of a few thousand, i.e., the reaction is shifted far to the right. In order to study this rather unbalanced gas composition, a flow method was used in two slightly different modifications. For all experiments with manganese silicides and for some experiments with pure manganese the apparatus shown on Fig. 1 was used. A bed of the metal or alloy was placed in a tube furnace. The refractory tube had an internal diameter of 14 mm and the bed was 75 mm long. Electrolytic manganese of high purity and silicon, 99.95 pct Si, were used as raw materials. All alloys were prepared by melting weighed amounts of the elements in a high frequency induction furnace in argon atmosphere. The melting was done in a silica crucible which was placed inside a graphite shell. The alloys were crushed to - 10 +40 mesh and analyzed chemically. Also, for the pure elements, the same size fraction was used. A controlled gas mixture of purified hydrogen and from 3 to 12 pct HC1 was passed through the bed where it reacted with manganese according to Eq. [I]. The volatile manganese chloride was collected in a condenser placed in the cooler part of the furnace tube. The gas mixture before and after the furnace was sampled and analyzed by absorption of

Jan 1, 1962

By H. R., Collins

THE purpose of pulverizing coal before burning it is to make available every heat unit it contains. Machinery has been developed which will pulverize coal in one operation, delivering it to bins in front of the furnaces at an expenditure of about 17 hp.-hr. per ton, in a medium-sized plant. The cost of the operation depends upon the amount of moisture that must be expelled before pulverizing, the cost of labor, and the cost of coal delivered at the plant. At a small plant, requiring a pulverizer with a capacity of only ½ ton per hour, the cost per ton pulverized will naturally be greater than at a plant requiring the largest pulverizer, with a capacity of 7 tons per hour. The first step is to reduce large lumps to a size suitable for drying uniformly, before passing to the pulverizing mills; this is done in rolls, at a single pass. The second -step is the elimination of moisture, in order to facilitate pulverizing to great fineness, while also increasing the heating effect and the temperature attainable when the coal is burned. There are other mechanical advantages in the handling of, dried coal. Driers are now manufactured which are able to eliminate moisture without distilling any of the volatile combustible matter in the coal; they are fired by hand or with pulverized fuel. The heat first surrounds the shell of the drier, being confined within a chamber where complete combustion takes place; the heated gases are then led through a duct to the discharge end of the drier and enter the inside of the shell at a temperature not exceeding 300° F. This temperature is maintained by the operator and is indicated by a pyrometer. Volatile combustible matter is not likely to be distilled until the temperature rises above 400° F. On discharging from the drier, the coal is usually passed over a magnetic separator in order to prevent pieces of iron from going to the pulverizer. Two types are used: a magnetic pulley which automatically discharges its collection of iron, and a lifting type, from which the iron is removed by hand when convenient.

Jan 4, 1918

By H. Hooykaas

A few years ago Marsal published a method of predicting oil recovery as a function of time for an edge-water-drive reservoir with several rows of wells.' The method is based solely on oil- and water-production data obtained during a short period for the first row of wells and the gross productions (past and future) of all wells. This paper presents a streamlined version of the original publication and experimental evidence showing the reliability of this version. For this purpose scaled experirnents were performed in a large model (750 X 500 X 23 cm, 24.4 ft X 16.2 ft X 8.9 in.) in which edge-water-drive reservoirs with three rows of production wells were simulated. From the results of the experiments it is concluded that the method gives a fairly accurate prediction of the future production behavior of the reservoir and enables us to select the most profitable production plan. Results obtained with the method were always slightly conservative. INTRODUCTION The calculation method developed by Marsal aims at forecasting future reservoir behavior.' It can be applied to floods in which a number of down-dip wells are rapidly going to water. Essentially it is a method for predicting the future behavior of the up-structure wells on the basis of the observed behavior of the down-structure wells. As such, the method is especially useful for predicting behavior of edge-water drives toward several rows of wells. The requirement to be met for justifying the approach is identity of production mechanism in all regions of the reservoir. The attraction of the method then lies in the fact that it applies even when we have no complete description of the prevailing production mechanism. The original publication was in the German language and for this reason, perhaps, did not attract widespread attention. In our opinion it deserves to do so because it does offer in a simple way results which are in fair agreement with observed data. The aim of the present paper is to bring the method to the attention of a wider audience. The method in its most simplified form is reviewed and experimental data in support of it are presented. PRINCIPLES To show Marsal's principle. we will first write the continuity equation for very simple conditions, linear flow (in the positive x-direction) in an incompressible porous body [cross-section A(x), porosity +(x)], saturated with incompressible fluids (oil saturation S). When the oil in this formation is displaced by water, injected at x = 0 (inlet face), we get where q(t) is the total gross displacement rate and f the fractional oil flow. The equation can be solved if we make the assumptions: (1 ) that the fractional oil flow (f) is a univalent function of saturation (S); and (2) that the function is the same throughout the porous medium. Then: f = f(S) Solving this equation with the method of characteristics, we obtain

Jan 1, 1966

NEW, MEMBERS The following list comprises the names of those persons who became members during the period July 10, 1916; to July 31, 1916: BOYD, ROBERT RUSSELL Supt:,-Arizona -Commercial Min Co., Globe, .Ariz. BRADLEY, HENRY FRANKLIN, Chem, American Smelt & Ref. Co. Murray,:Utah: BROWN, THOMAS ELLIS, JR..:'. L .:.::..55 Hill, St;; Morristown, N. J. CARY, WEBSTER P., Expert Operator,-General Engineering. Co:, Salt Lake City, Utah. CLARK, ALONZO WEBSTER 3223_ Scottwood Ave., Toledo, Ohio. CORP, CLIFFORD Old Dominion Copper Min. & Smelt. 60., Globe, Ariz. CROMBIE, W. RANSOM, Min. Engr Detroit Copper Min. Co., Morenci, Ariz. DELANEY, EUGENE A., Chief Engr., Berwind-White. Coal Mining -Co., Windber, Pa ELBELT, WILLIAM HENRY, Dept. Foreman., Chino Copper Co., Hurley, N. Mex. FOSTER, L. JULIO, Mgr., Minas i Fundicion ; ?La Junta," San Bernardo, Chile, South America. GASKILL, JAMES PHILLIPS, Genl. Mgr.,.Ajo Cons. Copper Co., Ajo, Ariz., via Gila, Ariz. .

Jan 9, 1916

By Raymond B. Ladoo

TIIe milling of talc, as is the case with many non-metallic minerals, until recently, has not received adequate technical consideration, for the talc industry has become of importance only within the last decade. At first, talc was used only in the massive form, for foot warmers, griddles, and so on, and milling methods were unnecessary. As the demand for ground talc increased, producers adopted the machinery used in the milling of flour; in fact, many talc mills were rebuilt flour mills. Improvement has been slow, but today several types of grinding and separating machinery are in use; many of them, however, are still inadequate and inefficient. To determine the best methods of milling talc, it is necessary to understand the essential properties a talc must possess to fit it for a particular use. For toilet purposes, whiteness, freedom from lime and grit, fineness of grain, and good "slip" are essential. As a paper filler or coating, the talc must be white, uniform, and fine grained, have a good slip, and be free from grit and iron; freedom from lime is a disputed point. Fibrous talc is supposed to be superior to massive on account of the interlocking of grains in the paper, thus increasing its strength; this point, though, is in doubt. In general, talc for the paper industry need not be of as high quality or as fine grained as that used for toilet purposes. Talc is usually bought by sample, for which reason it is difficult to state the essential properties for use in paint, rubber, roofing, and so on. The adoption of standard screen tests and standard grades by producers is necessary before an accurate basis for manufacturing or selling standards can be established. Off-color talcs might be utilized, as in Germany and Austria, by the establishment of standard grades of colored talcs. The machinery to be used depends on whether the talc is fibrous, foliated, or massive; hard or soft; of uniform or variable grade; pure or impure. In some cases, it is possible to change the mining practice or to utilize different sections of the deposit in order to vary some of these factors, but in many cases these factors are fixed, so the milling must be designed to suit the conditions.

Jan 1, 1922

The Murray Plant of the American Smelting & Refining Company is situated seven miles south of Salt Lake City, and has a fine view of the Salt Lake Valley with its fertile farms and orchards. It is located on the Los Angeles & Salt Lake and Denver & Rio Grande Western Railroads, and has a fine electric car service, cars running every 15 minutes. The beautiful and majestic Wasatch range lies about five miles to the east and the Oquirrh Range to the west, and from these mountains a large proportion of the ores treated are obtained.

Jan 1, 1925