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By Clintford R. Jones, Om P. Pande

This chapter presents a survey of instrumentation and control systems used on ball mill circuits from the past to the present. It is based on the concept of optimization of plant practice, and addresses the influence of the circuit design on the control strategy and on the instrumentation philosophy. Methods of optimization of the grinding circuit, within the constraints of the mill design requirements, are reviewed. The modern use of automation and circuit optimization is critically reviewed for known and possible conceptual control loops. A comparative study of circuit variations due to instrument hardware, location and installation is provided. Future trends i.e., computer control (DDC) and the effects on both the control stratagems and the optimization stratagems are described.

Jan 1, 1982

By F. O. Shuck, F. E. Butler

A diaphragm diffusion cell suitable for use with liquid metals was designed and tested by measuring the diffusion coefficients for a Hg-10 pct In alloy at 25°C. The binary diffusion coefficient and the coefficients for In and Hg tracers were measured at this composition. The measured coefficients for both tracers were less than the binary diffusion coefficient. When these coefficients were combined with the activity correction term of Darken, the predicted binary coefficient was somewhat higher than the experimental value. In recent years a number of investigators have been studying diffusion of liquid metals in order to gain a better understanding of the liquid state and to examine possible applications to liquid metal processing. The bulk of this work has involved either self-diffusion or diffusion of low concentrations of solute metals in an essentially pure solvent metal. The most common experimental technique employed has been the capillary-reservoir method of Anderson and saddington1 since it is well-suited to measurements involving low concentrations of solutes. As an expansion of previous studies, an investigation of the variation of diffusion coefficient over large composition ranges has been undertaken in this laboratory. Although it is possible to modify the capillary-reservoir method for such measurements, the technique loses its principal advantage of requiring only small quantities of solutes. Therefore, it was felt desirable to investigate other possible experimental techniques applicable to measurements over large composition ranges. A technique which has been used widely in measurements of other liquid systems and seemed potentially applicable to studies of liquid metals was the diaphragm cell. This method has been found to combine relative simplicity of operation with accurate and reproducible results. In use with normal liquids, the tyiical diaphragm cell utilizes a porous glass disk. However, because of the high surface tension, it is not possible to use a diaphragm of such fine pore structure with liquid metals. Furthermore. projected use at high temperatures makes the use of glass undesirable. Consequently, the first problem was the search for an appropriate cell design. EXPERLMENTAL Diaphragm Cell. A number of possible cell designs were examined. Prototypes of several were constructed and tested. The final design is shown in an exploded view in Fig. 1. The cell consists of two identical chambers, one on either side of a 0.20-in.-thick partition. The chambers are 0.15 in. deep and have a volume of 3.45 cu cm. Each chamber is provided with two small threaded holes for filling and emptying. The filling holes may be sealed with stainless-steel screws. Drilled lengthwise through the center partition is a 0.250-in.-diam hole. Inserted into this hole is a rod having seven 0.059-in.-diam holes drilled radially through it. The total "hole" volume is 0.078 cu cm. When the rod is properly aligned, the holes in it constitute the "diaphragm" through which diffusion occurs. The center section was of Teflon and the rod and face plates were of Plexiglas. Four such cells were constructed and used in this study. Subsequent to this investigation, a similar cell constructed entirely of iron was fabricated and tested at higher temperatures. Several considerations led to this final design. It is desirable to minimize the volume of the cell chambers to decrease the time required for a measurement. However, the total volume of metal in the diaphragm must be small in comparison with that in the chambers. To facilitate filling and emptying it is desirable to have a diaphragm which may be closed.

Jan 1, 1970

By J. Marshall Downey

The most fortunately situated U. S. potash producer-whether in New Mexico, California, or Utah--once simply took from the ground a mixture of sodium chloride and potassium chloride, crushed it to a maximum of 10 mesh, and separated the two salts by physical methods. He piled the sodium chloride on the desert and sold the potassium chloride to fertilizer mixing companies. Seven companies in the Carlsbad basin of New Mexico now use at least three basic processes for making the separation and at least three more processes have been or are under investigation. In addition, two companies outside the basin use two methods for taking KC1 from natural brines

Jan 12, 1958

By E. P. Pfleider, E. G. Malmlow, F. Landau

Friction drive hoists, long popular on the Continent, are now being installed in the U. S. and Canada by the Swedish firm of ASEA. Invented by C. F. Koepe and used first in 18.77, the principle is the same as that in elevator installations throughout the world. Inherent advantages of this system of hoisting were not fully developed until the recent introduction of the multiple-rope principle and design of concrete tower installations. Operators have a choice of independent operation of single skips and cages using counterweights, or use of skips or cages in balance. Also, hoisting control may be automatic, push button, or manual.

Jan 1, 1955

By C. M. Brown

Selection criteria for the instrumentation employed in semi-autogenous grinding circuits are reviewed. Instruments in use for grinding mill and related process equipment start- up, shutdown, protection, monitoring, control, and performance reporting functions are discussed with examples given of current industry practice. The quantity and type of instrumentation used vary from operation to operation, but today many semi- autogenous circuits are highly instrumentated, and employ automatic process control for both circuit stabilization and optimization of economic performance. Examples of analog and digital based control systems exist, and are described.

Jan 1, 1982

By R. R. Unterberger

Three different physical techniques have been used to see through or probe into rocks, so miners might know what is ahead or overhead. These are radar, sonar, and a unique type of sonar called nonlinear sonar. Five radar systems have been developed. The highest frequency used is 4300 MHz for detecting small fractures at close range. This gives the best resolution. For longest range (over 2000 m, or 6560 ft) we use the 30 MHz radar for finding faults ahead of mining or ranging to salt dome flanks. Two types of salt, dome and bedded, are recognized. Radar works well in dry (dome) salt, but not in bedded salt which contains small amounts of water. The dipole moment of water absorbs energy from the radar. Thus was born the 30 MHz radar system and sonar probing systems. These can probe to 100 m (328 ft) even into wet salt. All probing systems measure data in time, which are converted to distance by measuring the time of travel of radar or sonar through salt pillars of known thickness. Ranges of probing in salt are from less than 1 m (3.3 ft) to more than 2000 m (6560 ft). Uses of radar and sonar probing in mines include mapping the top of salt above a mine; mapping salt dome flanks; finding impurities in salt such as anhydrite, sandstone, or potash stringers; locating old boreholes in salt pillars; locating fractures in salt; and finding faults or water zones ahead of mining.

Jan 1, 1985

Jan 1, 1908

On July 25, the first copper ore From American Smelting & Refining Co.'s Mission open pit nine was sent into the new 15,000-tpd concentrator : three clays later, the first rail cars containing the Mission concentrate were sent north to the smelter at Hayden, Ariz. Thus two y,ears after stripping was started, Asarco's new mine, located south of Tucson. went on stream several months ahead of schedule. The plant, designed and constructed by Western Knapp Engineering Co., is expected to be operating at full capacity about September 1. with present plans calling for the copper concentrate from Mission to be shipped to Asarco's smelters at Hayden and El Paso.

Jan 9, 1961

NEW MEMBERS. The following list comprises the names of those persons who became members during the month of March, 1913 BAECHTOLD, CHARLES A., Engr 9G Liberty St., New York, N. Y. BRANTLY, JOHN E., Instructor in Geology Tuscaloosa, Ala. CADDY, JAMES P., Net., ,Lake View & Star, Ltd Fimiston, West. Australia. LONERGAN, PHILIP J., JR., Prof. of Mining, Government University, Peking, China. MCKANNA, EDWIN A., Min. Engr P. 0. Box 834, Oklahoma City, Okla. MACDONALD, ANGUS W., Supt. Labor Dept., Dominion Coal Co., Ltd., 21 Queen St., Sydney, N. S., Canada. TSUBOI, Yoshio, Min. and Met. Engr., Kosaka Mine, Fujita Co., Akita-ken, Japan.

Jan 4, 1913

By AIME AIME

CORROSION of tanks, pipes and other equipment in the oil fields is becoming worse as the production of high- sulfur crudes in the Texas panhandle and west Texas areas increases. It has been estimated that .in certain fields of that State one tank out of every five has to be replaced every year because of the high sulfur content of the crude. One suggested method for combating tank corrosion is the use of .materials which have a high resistance to the corrosive action of hydrogen sulfide and high-sulfur crudes; aluminum is one of these materials. As a result, the United

Jan 1, 1929

Discussion of the paper of CLARENCE A. WRIGHT, presented at the St. Louis meeting, October, 1917, and printed in Bulletin No. 130, October, 1917, pp. 1565 to 1591. H. A. WHEELER, St. Louis, Mo.-This paper by Mr. Wright is one of the most thorough and exhaustive studies that has been made of the milling practice in the Joplin district. Mr. Wright spent about two years there, in behalf of the U. S. Bureau of Mines and the Missouri Geological Survey, and this paper, which is the result of his work, will, repay careful reading by any student of ore dressing and is invaluable to an operator in that district.

Jan 1, 1918

By Bruce A. Lamberton

In U. S. underground mines concrete work is not widely used. Timber and steel are cheaper, and there are few serious water problems. But in the Union of south Africa men dig deeper, more persistently, and probably more profitably than anywhere else on earth. Some gold mines near Johannesburg are below the 10,000 level and employ as many as 35,000 natives on a single property. Underground substations, pump chambers, and air conditioning plants have capacity to serve small cities. The complexity and extent of underground operations and the heavy subsurface water flows, especially in the new Free State gold fields, require heavy in a Deep concrete installations.

Oct 1, 1956

By E. P. Pfleider

IT is generally believed that the amount of diamond drilling will increase appreciably in the next decade, as the search for minerals throughout the world becomes more difficult and intense. An attendant problem may be one of short diamond supply, resulting in higher bit and drilling cost. With this background, the U. S. Bureau of Mines1 and the School of Mines at the University of Minnesota2 have established comprehensive research programs in diamond drilling. One of the several aims is the design of a more efficient bit, which would lower diamond consumption and increase rate of advance, both essential in reducing drilling costs.

Jan 2, 1953

By C. M. Wayman, J. F. Breedis

The crystallography of the martensitic transformation in the Fe-30 Ni alloy was reinvestigated. The scatter in the habit Plane as determined from measurements on the mid-rib plane was smaller than reported previously, and the orientation relationship was determined from a martensite plate having known direction cosines. From agreement with crystallographic theory and from observations of the morphnlogy of the martensite plates, it is suggested that the mid-rib plane represents the starting region of the transformation. THE crystallography of the martensitic transformation in the iron-nickel system has been the subject of many investigations.&apos;-7 However, for iron alloys containing approximately 30 wt pct Ni, a wide scatter in the reported habit planes exists. In only one instance has a Laue determination of the orientation relationship been made, but the habit plane of the martensite plate studied was not determined experimentally. Because the most successful thermodynamic and kinetic analyses8 of the martensite transformation have been based on Fe-30 Ni alloys, it was considered desirable to reinvestigate the crystallographic features of the transformation in this alloy. Lieberman9 suggested that the most significant information for use in a theoretical treatment involves the determination of all the crystallographic observables from a single plate of the product phase. This was first done in essence by Greninger and Troiano10 for Fe-22 wt pct Ni-0.8 wt pct C, and is the method followed in this investigation. Some theoretical approaches11-13 in describing the martensitic transformation consider the overall transformation distortion to be comprised of a Bain distortion, or lattice deformation (PI, which produces the structure change, and a lattice invariant deformation (G), such as twinning, which together leave the interface or habit plane un-distorted. The incorporation of a rigid body rotation (R) results in a transformation distortion (E) such that the interface plane is left both undistorted and unrotated. In matrix notation, E = RPG where the lattice invariant deformation has "taken place" in the austenite. Bowles and Mackenzie14-16 in formulating a theoretical approach proposed an adjustable scaler quantity, denoted as 6, which represents a uniform dilation in the interface plane. This dilation acts to adjust the lattice spacings of the parent and product structures at the plane of contact. Using the dilation parameter as a variable, these authors were able to account for a continuous variation of habit planes in steels along a curve in the stereogram between {225}A and {259}A. she invariant line strain14 of the transformation is 6 RP, and the corresponding transformation distortion is E/6.) With the dilation parameter known, the invariant line is computed as the triple coincidence of the habit plane, the shear plane of the lattice invariant deformation, and the initial Bain cone.14 The contraction axis for the Bain distortion can be taken9&apos;17 as [010]A, and the correct permutation of the habit plane indices used. Kelly and Nutting 18 have established the shear plane (of twinning) in the tetragonal martensite of Fe-22 Ni-0.8C to be {112)M by means of transmission electron microscopy. The reasonable shear system is then {112}M which is equivalent to {011}A <01l>A. The as-

Jan 1, 1962

By Hiroshi Kato, Shin’ichi Nagashima, Hiroshi Takechi

The preferred orientations detleloped during cold rolling, annealing, and hot rolling of low-carbon steel sheets have been investigated by means of an inverse pole figure technique. And X-ray line profile meas-urerrlents were made for the study of the factor which causes the textural changes between cold-rolled and recrystallized sheets. From ND (sheet normal divection) and RD (rolling direction) inverse Pole figures tlze axis detisity change with increasing cold reduction was measured and the Preferred orientations were analyzed. These results can be explained by crystal rotation due to slip during rolling deformation. The ND axis density change during annealing of cold-rollitig sheets is contrary to the change observed in the case of rolling. It was found that the orientation dependency of stored strain energy resulting from cold rolling apparently corresponds to the textural changes during recrystallization. The texture in hot-rolled sheets was found to be influenced by finishing tenlperatltre. In a sheet kol-rolled below the Ar, temperature a significant differernce in texture between the surface and central layers was obtained, the former having {hkl}(111} and {110 )(uvw) orientations and the latter having {pqr}( 110) orientation. A large number of investigations1 6 have been made on the textures of iron and low-carbon steel sheets, and, since it was shown7 13 that preferred orientations are closely related to deep drawability of steel sheets, studies14" 7 on the influence of production processes upon textures have been made from the standpoint of industrial interest. Generally, the textures in low-carbon steel sheets have several components of preferred orientations, but the overlapping of poles makes it difficult to analyze texture quantitatively from pole figures. On the other hand, an inverse pole figure directly expresses quantitative values of components of preferred orientations as the density of a certain sample axis with respect to the crystallite coordinates. Such a texture representation is desirable for a study of deep drawability. The purpose of the present work is to use both inverse and conventional pole figures, with emphasis on the former, to clar~fy the textural changes ~n low-carbon steel sheets by the production processes of hot rolling, cold rolling, and annealing. And the factor causing the textural changes during annealing is studied using an X-ray diffraction line profile technique. EXPERIMENTAL PROCEDURE Sheet specimens for study of cold rolling and annealing textures were taken from a hot-rolled strip of rimmed steel 2.7 mm thick. The chemical composition is shown in Table I. Although the study of cold-rolling textures requires a suitable material with random orientation, it is difficult to produce a perfect random one. But the used specimens, obtained from the hot-rolled strip with a finishing temperature higher than Ar3, were nearly random, such as shown in Fig. 15. These were cold-rolled to various reductions by a 4-high rolling mill with 150-mm-diam work rolls and 300-mm-diam backup rolls. The influence of hot-rolling conditions such as finishing and coiling temperatures on textures of hot-rolled strips was studied. The chemical compositions of these hot coils are given in Table I1 and the hot-rolling conditions are given in Table 111. inverse Pole ~i~ure -~easurement. Two methods for determining inverse pole figures with high precision have been proposed. The first, by Jetter et a1.,18 consists of obtaining mean densities of divided regions in a unit stereographic triangle by solving simultaneous linear equations to approximate the integral relation between conventional and inverse pole figures. The second, proposed by ~oe&apos;~-&apos;~ and Bunge,22&apos;23 consists of determining an expanded series of spherical surface harmonics which express axis densities from several sets of pole distribution data. Both methods require laborious numerical calculations which make them unsuitable for practical use. However, the axis densities of the locations corresponding to low Miller indices in a unit stereographic triangle can be obtained

Jan 1, 1969

By C. B. Barlow, T. A. Mekelburg

Due to a tight ash constraint on the clean coal product and difficult middlings washability characteristics, a considerable amount of coal was being lost in the jig middlings at the Monterey No. 2 Mine. An investigation was conducted into circuitry to recover this lost coal with minimal effect on the total clean coal ash. A reverse two-stage hydrocyclone system cleaning at low specific gravities was selected. This system is currently recovering approximately 5.8 kg/s (23 stph) of 11.5% to 12.5% ash coal. The specific gravity of separation for the system is about 1.5 and the probable error is 0.13.

Jan 1, 1986

By Prof. B. Hopkinson

Introduction.-A short time ago Professor Stoughton asked the writer if he would present a paper for the February meeting of our Institute. In reply to this suggestion, some notes have been prepared relating to the subject mentioned in the title. It is to be hoped they may be of interest to our members. The research now described is the joint work of Prof. B. Hopkinson, F. R. S., and the writer. Those interested in the subject will find further data in a paper entitled The Magnetic and Mechanical Properties of Manganese Steel, which will probably be read at this year&apos;s May Meeting of the Iron and Steel Institute in London. This paper was submitted to the Institute in October last, and advance copies will shortly be available. The present paper has been drawn up by the writer on this side the water, and he has not had time to communicate with Professor Hopkinson with regard to the statements or opinions expressed herein. While the writer believes that Professor Hopkinson would in the main agree with the statements herein set forth, it should be understood that apart from the actual work described he is not otherwise responsible. The experiments described have been carried out on the material known as manganese steel, which one of the writers of these notes discovered in 1883. A paper by him describing this material was read before this Institute in 1893, entitled Iron Alloys, with Special Reference to Manganese Steel. It is not necessary to describe manganese steel nowa-days; its qualities are so well known, and its use throughout the world is on a very extensive scale.

Jan 3, 1914

NEW MEMBERS. The following list comprises the names of those persons who became members during the month of October, 1913: Members. BARNES, KENNETT F., Secty Granby Min. & Smelting Co., St. Louis, Mo. BILLINGSLEY, PAUL, Geol 526 Hennessy Bldg., Butte, Mont. BLANCHORD, RALPH C., Geol 3 Lombard St., London, England. BOYLE, ALBERT C., Jr., Prof. of Min. and Met., University of Wyoming, Laramie, Wyo. BRADFORD, JULIUS S., Min. Engr Chiksan Mining Co., Chiksan, Korea: CLEMES, ALFRED W., Min. Engr P. 0. Box 6,88, Moronic, Ariz. COPELAND, DURWARD, Met Cia. Estamifera de Llallagua, Bolivia, So. America. CRAWFORD, JOHN, JR., Mgr Noble Elec. Steel Co., Heroult, Shasta Co., Cal.

Jan 11, 1913

By Duane N. Goens, Clifford R. Porter

A 91 kg/h (200 lb per hr) pilot plant was constructed according to "Magnex" design. A non-compliance eastern coal which would generate more than 0.85 kg of S02 per GJ (2.0 lb of SO2 per million Btu.) upon burning was brought into compliance less than 0.52 kg of SO2 per GJ (1.2 lb SO2 per million Btu) during continuous operation of the pilot plant. Approximately 85% of the pyritic sulfur was removed while recovering 90% of the Btu of the feed coal. Pilot plant operation is summarized and preliminary economics presented. Present status of the Magnex design program is reviewed.

Jan 2, 1979

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period Apr. 10 to May 10, 1915: William W. Elmer, Tuttletown, Cal. R. R. Freeman, Jr., Wollaston, Mass. Lawrence Addicks, Douglas, Ariz. Francis R. Pyne, Elizabeth, N. J. W. F. Durand, Stanford Univ., Cal. George B. Pickett, Ophir, Colo. S. P. Cooper, New York, N. Y. R. V. Norris has been elected President of the Columbia School of Mines Alumni Association. Robert C. Sticht has been elected President of the Australian Insti¬tute of Mining Engineers.

Jan 6, 1915