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By Charles Jones

(San Francisco Meeting, September, 1915) IN any discussion of this very large subject we are confronted at the outset with so many obstacles that at best only a fragmentary and rather disconnected presentation can be made of it, and my hope is that building from the few facts I have to offer a more complete knowledge may be secured. In the whole intermountain and Pacific. Coast region, west of Pueblo, Col., and from Canada to Mexico, there is no production of pig iron, and steel production is confined to the manufacture of a small amount of open-hearth steel from scrap. When we consider the area, the resources, and the several centers of population, this condition seems anomalous, even in. the face of every counter argument as to cheap water transportation, or other means of transport from the Atlantic Seaboard or from the iron and steel centers of the Middle West. This comatose condition, if such a term may be applied, is certainly riot due to a lack of all the essential materials and factors for success in iron and steel smelting, but is rather, I think, due largely to the general fact that it is only within a comparatively few years that the centers of population on the Pacific Coast have attained a size that would entitle them to the position of distributing or freight centers, or that the "back country" has been enough built up to make it sufficiently interesting to the railroads to foster trade from the local centers to the interior points rather than seek to supply such local centers and the interior by a transcontinental haul.

Jan 9, 1915

By Samuel Gibson Frantz, G. W. Jarman

The purpose of this paper is to relate briefly the development of magnetic separation and its extension from the separation of iron into its present use in the nonmetallic field, to suggest possible future extensions of its field of usefulness and its possible cooperation with other separating methods. The engineering design of separating machines, and statistics as to the number of machines in operation, types, their location and production are outside the scope of this paper. Specific data will be given, however, on certain selected applications. A large part of human endeavor consists in separating one thing from another; the good from the bad, the desired from the undesired. In fact, a philosopher might plausibly claim that separating things into categories and choosing between them is the object of thought itself. In dealing with matter, separation is nowhere more inherently necessary to attain our objects than in mining and metallurgy. Both our desire and our ability to make separations are results of the physical differences between things. Gross separations such as removing ore from worthless rock or coal from slate are usually made visually and depend upon form and color, which are physical properties. When the desired and the undesired things are intimately mixed, however, it becomes impractical to select visually even if the individual particles are readily recognizable to the eye, and some automatic way of making the particles separate themselves on the basis of their own inherent differences in physical properties must be resorted to. Some of the physical properties which have been used as a basis of separation are: color, shape, hardness, size, density, elasticity, surface propertics (surface tension in contact with liquids, etc.), electrical conductivity, dielectric constant, and magnetic susceptibility. Differences in these properties are used in the following methods of separation: color sorting, sifting, settlement in air and in liquids, float-sink methods, flotation, electrostatic and magnetic separation.

Jan 1, 1932

By Stanley D. Michaelson

Stanley D. Michaelson retired in 1976 as chief engineer, Metal Mining Div. and director of the Engineering Center for Kennecott Copper Corp. An active consultant on mining and metallurgical assignments, Mr. Michaelson is also currently adjunct professor of mining engineering at the University of Utah. He received his B.S. degree in mining engineering from Lehigh University in 1934 and an honorary E.M. degree from the Montana School of Mines in 1961. Mr. Michaelson received AIME's Robert H. Richards Award in 1962 and was named a Distinguished Member of the Society of Mining Engineers of AIME in 1975. He has served as a Director and as a Vice-President on the AIME Board of Directors and is a Past President of the Society of Mining Engineers. He became an Honorary Member of AIME in 1978.

Jan 1, 1979

By Robert E. Green

Experiments were performed in order to investigate the influence of magnitude of driving force, recouery, and previous heat treatment on grain boundary migration in deformed aluminum crystals. The frequency of occurrence of strain-free grains possessing Preferred crystallographic orientations was studied both as a function of heat treatment and as a function of amount of deformation of the matrix crystal. Aluminum of such composition as to exhibit precipitation-hardening behavior was used. CONSIDERABLE work has been devoted to the factors influencing grain boundary migration in metals.1'52 Aust and Rutterl-9 have studied grain boundary migration into matrix crystals containing a striation substructure, which provided a thermally stable driving force during the course of the migration experiments. These authors state that, while variations in the striation pattern were sometimes observed, it was possible to obtain reasonably uniform and reproducible striation structure by careful control of the solidification conditions. Admittedly, this source of driving force is a unique one and has served well in numerous experiments. However, although the striation substructure provides a thermally stable driving force, the subject of its reproducibility from crystal to crystal is questionable. In fact, Aust and Rutter3 attribute the scatter shown in some of their experimental points and several anomalies in boundary migration rates to variations in the substructure driving force along a single specimen. A further limitation on striation-induced driving force is that the driving force cannot be varied over wide ranges in a controlled manner. More often used as a source of driving force is the strain energy stored in a crystal during plastic deformation. This type of driving force has the disadvantage that it is not thermally stable due to recovery taking place simultaneously with the grain boundary mobility measurements. On the other hand, this strain-induced driving force is very reproducible from crystal to crystal since it is very easy to grow single crystals possessing the same purity and crystallographic orientation and then to strain them identically. In order to measure grain boundary migration rates two different methods are primarily used. Most often the technique employed is the heat-cool-etch method1' which involves thermal cycling, while the other technique, developed by Graham and Cahn11 using an X-ray diffractometer and goniometer furnace, involves continuous heating only. Thus the influence of thermal cycling vs continuous heating is a factor to be considered in grain boundary migration rate measurements, particularly in cases where the source of driving force is the strain energy stored in the deformed matrix, and recovery is likely to occur. Numerous recent investigations have shown that extremely small impurity additions to zone-refined metals exert a marked effect on grain boundary migration rates1-5, 9, 12-27 and a few have considered the effect of the distribution of impurities.28-35 The concentration of impurities and their distribution as influenced by heat treatment must also be taken into account in migration-rate studies. In the present article consideration is given to the influence of the magnitude of driving force, recovery, and previous heat treatment on grain boundary migration rates. In order to vary the driving force over a large range it was necessary to use as a source of driving force the energy stored in the matrix crystal during plastic deformation. A majority of the investigations were performed on aluminum specimens which were of such compositions as to exhibit precipitation-hardening behavior.

Jan 1, 1965

Jan 1, 1911

Jan 1, 1925

By Ralph D. Parker

The Frood mine (Fig. 1) is 2½ miles north of Sudbury, at a general elevation of 1000 ft. above sea level. It includes the original Frood location, which was the No. 3 mine of the Canadian Copper Co., and the adjoining Frood Extension, which until 1929 belonged to the Mond Nickel Co. Mine Openings The mine is operated from two vertical shafts and one underground incline shaft. No. 3, for men, supplies and ore, is a vertical six-compartment shaft in the footwall of the south mining area and extends froin surface to a depth of 3045 ft. No. 4 is a vertical three-compartment shaft, 2500 ft. north of No. 3 and adjacent to the north mining area. It extends from surface to a depth of 3345 ft., and is used exclusively for hoisting ore. No. 5 shaft, inclined at 65' to the horizontal and of three compartments, is near No. 4 and extends from the 2600-ft. level to 77 ft. below the 3100 level. It is used for development below the 2800 level. The ventilation shaft, No. 1, with which this paper is directly concerned, will be described fully in the following pages. Mining Methods The orcbody is laid out in 80-ft. sections at right angles to the gcneral strike and numerically indicated from the southern extremity toward the north. Each section consists of a 45-ft. stope and a 35-ft. pillar, extending the full width of the orebody. Pillars and stopes are superimposed from level to level. The present mining territory is divided into two vertical areas, a north and a south area. Both areas have the same number of stopes on each level, the two areas being separated by 10 sections to be mined later. In a few instances, at the ends of the south area, where the orebody has narrowed, longitudinal stopes are used, of more than the usual 45-ft. width. It will thus be seen that mining operations hare been concentrated in two relatively small areas, offering

Jan 1, 1934

By James D. Reilly

13.1-1. Introduction. COAL RESERVES OF THE UNITED STATES. Bituminous coal is the most abundant fossil fuel in America. With reserves of 1,660 billion tons and assumed recovery of 5070, there is more than 830 billion tons of recoverable coal--enough to assure ample supplies of energy for centuries. Looking at Fig. 13.1-1, coal is found in a majority of the states, including [ ]

Jan 1, 1968

Jan 1, 1934

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Jan 1, 1938

By K. H. G. Ashbee, J. W. Heavens

One consequence of the distribution in orientation of Bragg diffracting planes in an elastically bent foil is that simultaneous diffraction occurs from ±g pairs, where g is the reciprocal lattice vector to a diffracting plane. If such Bragg contour pairs are indexed, then the variation in orientation with respect to the incident electron beam is known. This note describes a construction by means of which Bragg contour pairs may be indexed by inspection. Referring to Fig. 1, the Ewald sphere radius is l/h, where is the wavelength of the electron beam, and the half spacing of first-order reciprocal lattice planes is l/d, where d is the corresponding spacing in direct space. The angle subtended by the zero and first-order planes at the center of the Ewald sphere is a = sin-' Thus, to represent a pair of first-order Bragg contours on a stereographic projection, measure ±a from, and along the normal to, the zero-order plane. The traces of the required Bragg contours pass through these points and parallel to the zero-order trace. In practice, it is desirable to enlarge a stereographic projection of the zero-order planes before making the construction. As an example, a stereographic projection of first-order Bragg contours up to line 27 for an fcc crystal is given in Fig. 2; if required, higher-order contours can easily be added. Fig. 2 is, of course, a map of first-order Brillouin zone boundaries. One use of this construction is the measurement of large elastic fields in electron microscope specimens. Fig. 3(a) shows a pattern of Bragg contour pairs due to lattice distortions near a large precipitate. This particular example is of a T-phase precipitate in Hidu-minium 54 (A1 + 6 wt pct Cu, 0.5 wt pct Mn). Foil buckling is produced by annealing during observation and may be evidence for evaporation from the precipitate.' Comparing Figs. 2 and 3(0), it is evident that the axis of high symmetry in Fig. 3(a) is [lll]. The strain in a bent foil is approxinlately t/2r, where / is the foil thickness and ? the radius to which the foil is bent. From the projections of grain boundaries and of helical dislocations, it was estimated that ( - 3000A, and values for ? were obtained from the

Jan 1, 1968

By M. A. Mosher

Most modern electrolytic copper refineries have found it expedient to build and operate a complete secondaries plant for the treatment of the electrolytic slime accumulated in the cells during the corrosion of the copper anodes. In the earlier years this was done for the sole purpose of promptly recovering in marketable form the silver and gold contained in the slime. Later, improvements in refining methods made possible the recovery of the more precious metals such as platinum, palladium, osmium and iridium, and in recent years, due largely to an increasing market, many secondaries plants have undertaken the commercial production of selenium and tellurium. The complete up-to-date secondaries plant, or silver refinery as it is usually called, is therefore equipped for the production in marketable form of from six to eight metals. The physical plant and operations may be separated into six main divisions: 1. Slime treatment, in which the raw slime is treated by wet methods for the removal of its high copper content and portions of other impurities such as arsenic, selenium and tellurium. 2. Furnace refining, in which the remainder of the base-metal content of the slime is removed by fluxing and fire-refining. 3. Electrolytic parting and refining, in which the silver and gold are parted and obtained in the pure state. 4. Melting of silver and gold into marketable form. 5. Recovery and refining of the more precious metals. 6. Recovery and refining of selenium and tellurium. The Silver Refinery of the Raritan Copper Works at Perth Amboy, N. J., is a complete secondaries plant and the following description of its equipment and processes is, in a general way, typical of other plants of its kind. Slime Treatment The raw slime, pumped with a minimum amount of cell solution from the electrolytic copper refinery, is discharged into the center of circular settling tanks 15 ft. in diameter by 8 ft. deep, where the slime settles out and the solution overflows peripherally to return to the copper refinery by gravity. The slime is then dropped through a bottom outlet to a

Jan 1, 1934

By H. Colijn

Belt scales are frequently used in the mining industry because of the ability to handle large tonnages without interrupting the material flow, fitting easily into all types of bulk handling systems and being relatively inexpensive. Although manufacturers claim weighing accuracies better than Y2%, many operators experience, in practice, much larger errors and they have become apprehensive about the use of belt scales. However, in spite of these disappointing instances, a belt scale is one of the most valuable tools for process and inventory control. Since it is a measuring device, care should be given to the design and installation of belt scales. The basic components of a belt scale are: (1) conveyor belt, (2) scale suspension, (3) sensing device, (4) integrating and recording. The first component of this system is of great importance to the overall accuracy and has been thoroughly discussed in earlier papers. This paper will review primarily the various scale hardware designs currently available, and will be confined to the last three components of the system.

Jan 1, 1973

By B. G. Bunting, J. H. Johnson, H. J. Schock

This paper describes an experimental method for monitoring diesel-generated exhaust gas pollutants in a deadended drift to assess the effect of control approaches. Experiments were conducted to determine the relative merits of these ventilation configurations: no auxiliary ventilation, induction ventilation at the entrance to the drift, and ventilation of the dead-ended drift with positive displacement tubing. The drift used in this experimental work was approximately 32 m long and slightly downsloping, with an everage height and width of 2.4 and 8.6 m, respectively. For this drift, it was found that ventilation with positive displacement tubing provided the best removal of diesel-generate pollutants. Induction ventilation appeared to be the least effective of the three methods examined.

Jan 1, 1982

By J. Y. Oldshue

INTRODUCTION The field of fluid mixing involves many different kinds of process objectives. In order to classify these objectives, Table 1 gives a listing of five basic application categories, gas-liquid, liquid-solid, liquid-liquid, miscible liquids, and fluid motion. However, each of these areas can be broken up into two different concepts one involved with uniformity of solids or liquids as a criteria, and the other involved with chemical reactions or mass transfer. The things that we would do to design a fluid mixing for solid suspension are quite different from things that we would do to design a mixer for heat transfer or gas-liquid mass transfer. Therefore, there are really ten separate mixing technologies. Each of these areas has its [ ] own principles of fluid mechanics, scale-up techniques and application experience. We will take a look at each of these areas and look at some of the ways that we can handle fluid mixing applications which.

Jan 1, 1979

By 0. H. ESCHHOZ

HARMON F. FISHER,* New York, N. Y. Mr. Eschholz discusses the particular case of large precipitators installed in connection with large metallurgical operations, and receiving their high-potential energy through the conversion of alternating current to direct current by means of the mechanical rectifier. He classifies these mechanical rectifier installations, according to source of power, as follows: System A.-Applications utilizing individual alternating-current generators, either single-phase or polyphase, installed exclusively for furnishing energy to one or more transformer-rectifier-precipitator units. System. B.-Applications having no special alternating-current generators, but utilizing the existing alternating-current industrial or lighting mains to supply the energy to one or more transformer-rectifier-precipitator units. System C.-Applications receiving their energy from high-tension power circuits supplied directly to potential regulator-rectifier-precipitator units. I do not intend here to enter upon a detailed technical discussion of the foregoing classes, which would really interest only the manufacturers of electrical apparatus and the electrical engineers. A brief general discussion follows:

Jan 11, 1918

By C. O. Lee, Z. W. Bartlett, R. H. Feierabend

The Grand Isle sulfur mine is located in the Gulf of Mexico, approximately seven miles off the coast of Grand Isle, Jefferson Parish, La. The deposit is on acreage covered by oil, gas, and mineral leases originally issued in favor of Humble Oil & Refining Co. by the State of Louisiana which were continued, maintained, and redesignated by the U.S. Department of the Interior after passage of the Outer continental Shelf Lands Act. The sulfur deposit was discovered in 1949 when Humble Oil & Refining Co. penetrated more than 200 ft of sulfur-bearing limestone in a zone between 1813 and 2075 ft below sea level. In 1954, Humble drilled ten more sulfur prospect holes, eight of which encountered sulfur ore.

Jan 6, 1960

By R. B. Tippin, J. S. Browning

Inasmuch as the higher grade potash deposits are rapidly being depleted, it is important that economic beneficiation techniques be developed for recovering potassium compounds from lower grade sylvite ores and deposits containing clay materials. The Federal Bureau of Mines has conducted research to develop processes for heavy liquid concentration of potash ores, This method of concentration is discussed, and results of tests made on potash ores from New Mexico are presented. The tests demonstrated the technical feasibility of producing near commercial-grade potash concentrates, with a high recovery of the contained sylvite. The concentration of minerals based on their differences in specific gravity dates back to the very beginning of mineral dressing, and the use of heavy liquids in the laboratory to achieve optimum mineral separations has been utilized for many years. With the advent of froth flotation and its success, the incentive to develop new processes has remained relatively dormant. However, flotation refinements in the nonmetallic ores have not progressed as rapidly as in metallic (sulfide) ores because of the complexity of the deposits and the chemical similarities of the minerals.

Jan 1, 1967

By F. R. Hensel

THE absorption of oxygen by molten metals is a quick and convincing method to determine the metallurgical characteristics of various types of furnaces.1 The investigation was restricted to the use of coreless induction furnaces. A major variable in induction furnace practice is the frequency and its influence was studied by comparing melts made in a 5000-cycle and a 60-cycle induction furnace respectively.2 The authors are not aware that such a comparative study has been made before and therefore present this paper in the belief that the results will be of general interest. ANALYTICAL METHODS FOR DETERMINATION OF OXYGEN IN NICKEL An analytical procedure for determining NiO by a quick and simple, laboratory method has been worked out in collaboration with Dr. Herty, of the Pittsburgh Station of the Bureau of Mines. It was found that Dr. Herty's aluminum method as used for the. determination of FeO in iron and steel was very suitable for use with nickel if instead of hydrochloric acid a 10 per cent solution of nitric acid is used for bringing the metal into solution. Essentially this method involves deoxidizing the nickel-oxygen alloy with aluminum (2Al + 3NiO = Al203 + 3Ni) and determining the resulting Al203 by a residue analysis. The original oxygen content can then be calculated from the amount of Al-20,. The method as suggested by Dr. Herty3 is referred to in the present paper as method B. A slight modification of method Bled to the application of method A, a description of which is given below according to F. W. Beiter?:3

Jan 1, 1932

United Engineering Trustees, Inc. W. D. B. MOTTER, JR., '40 A. L. QUENEAU, '41 ALBERT ROBERTS, '39 The Engineering Foundation GEORGE D. BARRON, '40 F. F. COLCORD. '42 A. L. QUENEAU, '41

Jan 1, 1939