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By Nathaniel Herz

PARTING of bullion before shipment to the mint had been considered by the Homestake Mining Co. at various times, but had never been attempted before 1933, be- cause the margin of profit appeared to be too small to warrant the complications in refining. When the gold standard was abandoned by the United States in the spring of 1933, however, parting of the bullion was decided upon. The method selected was the Miller or chlorine process, which consists of the passing of gaseous chlorine into a bath of molten bullion, converting all metals other than gold into chlorides, and remov-

Jan 1, 1935

By AIME AIME

AT a joint meeting of the Tulsa Geological Society and the Mid-Continent Section of the A; I. M. E., held at Tulsa on March 21, the history of unit development in the Kettle- man Hills field was discussed. Robert C. Patterson? Super- visor for the U. S. Geological Survey at Taft, Calif., was the speaker. An abstract of some of his remarks follows: On July 1, 1923, curtailment agreement for two years was made between the operators of North Dome Kettleman and the U. S. Department of the Interior. In this it was agreed to consider a plan of unit development, or other cooperate method of developing the structure. As a result, Kettleman North Dome Association was incorporated in December, 1930, as a non-profit cooperative corporation under the laws of California. Approved in January, 1931, by California Oil and Gas Supervisor and by Secretary of Interior. On Feb. 10, 1931, it became an active organization through election of executive officers and eleven- directors. General manager chosen. Association started to function April 1, 1931. Assumed control of 10,800 acres of proved and semi-proved land, as shown in Table 1.

Jan 1, 1932

By O. E. Palasvirta

Several drum-type, low-intensity dry magnetic separators have recently been described 1,2,3,4 all of which share at least two generic similarities. The magnet consists of a multiplicity of poles of alternating polarity and, the speed of the drum shell, relatiw to the magnet, is such that the magnetics are agitated through rotation of the magnetic particles around their individual axes. The speed of the drum relative to the magnet (differential speed) determines the frequency of the field reversals. For effective agitation this frequency generally has to be above a specific value, which varies according to the mean particle size of the magnetics. With separators of small diameter, say less than 11/2 ft., a sufficient differential speed for treatment of fine magnetite can be attained only by rotating both the magnet and the drum separately; separators of large diameter may attain sufficiently high differential speeds with stationary magnets. Separators of large diameter thus have the advantage of simplicity of design. The capacity of a separator of this type is directly proportional to the speed of the shell. As the centrifugal force opposing the magnetic force increases at a slower rate than the peripheral speed of the shell when drum diameter is increased, large drums can be operated with higher peripheral speeds. Thus they have a higher capacity than smaller drums. Separation is also a statistical phenomenon, i.e. the grade of concentrate improves as the number of agitations or rotations of the magnetic particles per separation increases. As separators of large diameter have space for a large number of magnets they are best suited for production of optimum grade concentrate. The statements above are general clues For separator design. In the following an expression IS derived showing a more exact relationship between the pertinent separator variables. As both magnetic attraction and centrifugal forces are directly proportional to the volume of the affected bodies, complications in mathematical analysis, arising from variable particle size, are avoided by considering the force per unit volume of affected material. For the magnetic force per unit volume Runolinna (3) gives the following equation: V " 1 + N(ur, - 1) uo dr (1) where ur and uo stand for the relative permeability and the permeability of vacuum, respectively, N is the demagnetization factor, B the intensity of the magnetic field, and r the distance from the face of the magnetic pole. The permeability of a specific magnetite ore can generally be considered as a constant. For ground, liberated material N can also be treated as a constant, and the first simplification can be made by writing ur-1 1=k1. 1 + N(ur - 1) uD k1. Fig. 1 shows the field intensity curves for two U-magnets of different size, but of roughly similar geometry of cross-section as plotted against the distance from the plane of the pole faces. The curves

Jan 1, 1961

By Myron Read

DURING the past 25 years, mining engineers have seen the development of a multitude of specialized engineering curricula in the mineral industry field. Bachelor degrees are now !ranted in the fields of mineral dressing petroleum engineering, geological engineering, fuel technology, and many others. These fields were all, previously considered to be part of a mining enginieer's work and elementary phases of them were included in mining engineering curricula. Their emergence has left some mining engineers with the fear that nothing will he left for a purely mining engineer to teach, or that mining engineering graduates will be unable to complete in any of these fields with the more specialized students and thus will have neatly restricted employment opportunies. A secondary reaction has been that if students who began to say that the pining engineering curriculum taught everything but mining, since so many of :he subjects that had always been udedAuded in the mining engineering curriculum now were fields in their own right.

Jan 1, 1946

[Note.—The paper of Mr. Hoffman on " Practical Results in the Magnetic Concentration of Iron-Ore " (page 602); that of Mr. Langdon on "The Use of Magnetic Concentrates in the Port Henry Blast-Furnaaces" (page 599); and those of Mr. Landis on "The Determination of Iron in the Tails from Magnetic Concentration " (page 609) and "Note on Sampling Iron-Ore" (page 611), were all prepared as contributions to this discussion.] The papers of Mr. Langdon and Mr. Hoffman were presented. W. H. Hoffman, Croton Mines, N. Y.: I will add a few remarks, by way of answer to inquiries for further details. The Croton Mines are particularly well located for cheap mining. The ore-bed is very large, and so lies in relation to the railway tracks of the Harlem and other railroads that a very large proportion of our mining for several years to come can be done above these tracks. The concentrating-mill is now 400 feet from where we are working in the quarry. In blasting we never remove less than 2500 tons at a blast,

Jan 1, 1892

Jan 1, 1961

By R. C. Mahon

Operators concerned with the destruction of their piping by acid mine waters will be interested in the method by which this problem was solved at the Cardiff mine of the Homer group. Rubber lined, or acid resisting metal pipes were found too expensive. Casting concrete lining in pipe would have required a minimum thickness of one inch, thus excessively reducing the pipe's diameter, as well as taking twenty four hours per length of pipe. The Naylor Pipe Co. of Chicago, having experimented with centrifugal lining of pipe with concrete, provided information which eventually solved the problem. An experimental plant was constructed as shown, and the following procedure developed : (1) Kerosene is used to remove the interior oil coating of new pipe. Closed with blank flanges, the pipe is revolved for eight minutes at varying speeds. Stopping and starting the motor achieves a good washing action. The kerosene is then drained off, and similar washing action with caustic soda removes any excess. Swabbing in done with burlap fastened to a 1/2-in. pipe. (2) The aggregate, made of one. part quick-setting cement and two

Jan 1, 1949

By F. H. Buchella, J. F. Buchanan

The San Manuel copper deposit is located about 45 miles northeast of Tucson. The concentrator, smelter, administration building, and other plant facilities are located about seven miles southeast of the ,nine area at the new town of Sari Manuel as shown on Figure 1 (Sketch).

Jan 1, 1961

By H. I. Althulee

The mines operated by the Compañía de Real del Monte y Pachuca, Pachuca, Mexico, are in two districts, the Pachuca, and Real del Monte. The principal area of mineralization is within a rectangle roughly 10 miles from east to west and 6 miles from north to south. It contains a number of veins from 2 to 20 ft. wide, which are exploited by this mining company. The scattered position of the producing mines led to the construction of two mills between 1906 and 1908; the Loreto mill, in Pachuca, averaged 2600 tons daily, and the Guerrero mill, in Real del Monte, milled 1270 tons daily. On Feb. 1, 1929, the management decided to enlarge the Loreto mill to take the combined tonnage of both mills at that time. This economic measure required the centralization of ore delivery, which would also afford a material saving in the cost of ore transport. The centralization would give the company the following advantages over the former system of operation: 1. Beneficiation at a single mill, closer to source of materials and supplies than the abandoned Guerrero mill. The refinery is also in the Loreto patio. 2. Ore delivery to surface at one point (San Juan Pachuca shaft) instead of at four. 3. Elimination of aerial tramways. To show what would be required to effect this centralization, it is necessary to describe the means by which the ore was delivered to the two mills, prior to centralization. The heart of the Real del Monte district is roughly four miles from that of the Pachuca section. The producing mines in these two districts were: Pachuca district: Real del Monte district: Santa Ana mine La Rica group Camelia group Purisima group Santa Margarita mine

Jan 1, 1934

By C. M. Young

THE following paper has been prepared with the object of placing on record in the Transactions some facts concerning the present condition and future prospects of the coal industry of Illinois. In presenting it, the writer wishes to say that a considerable amount of the material contained is taken from the publications and records of the Illinois Coal Mining Investigations, the annual Coal Report of the State Mining Board, and the work of the State Geological Survey. Coal Beds and Mining Methods According to the latest maps of the State Geological Survey, there are only 19 of the 102 counties of the State some portion of whose territory is not within the borders of the coal measures. If outlying areas in Calhoun and Whiteside Counties are considered, the number is reduced to 17. This does not mean that all of the 85 counties that are partly or wholly underlain by coal measures will become producers, as there are some portions of the State in which the coal does not occur in beds of such thickness as to warrant the hope that it can be mined. The mining of coal is widespread, however, for in 1916 there was production from 51 of the 102 counties of the State. There seem to be no cases in which operations will be limited by depth, as none of the coal measures lie at depths much greater than those at which it has been proved that coal may be profitably mined in this field. In fact, the deepest shaft reaching a bed of bituminous coal in the United States is located in this State at Assumption, where coal only 3 ½ ft. (1.07 m.) thick is worked at a depth of 1004 ft.. (306 m.) The coal beds occur in the form of a basin which is deepest along a line extending through the central part of the State and bearing a, little west of north. The northern, western and southern borders of this basin lie within the boundaries of the State, but on the eastern side the Illinois field is continuous with the Indiana field. The glacial drift covers all except the extreme southern end of the State and the visible outcropping

Jan 9, 1917

By H. F. Silliman, Daniel R. Hull, Earl W. Palmer

THE brass-rolling industry has not had a great deal of experience with antimony in its product. There have been some recent excursions with antimony as a corrosion inhibitor in tubes, but in sheet brass it has been regarded with apprehension and generally avoided. This is not to say that [ ] contaminations have never occurred, and probably a great many brass mill men have had their own ideas on the effect of such contamination. Our own views were based upon certain experiences some years ago with strip castings that split lengthwise in the early stages of rolling. The nature of this splitting is shown in Fig. I, from a photograph taken in 1922 as a record of 20 bars of 65-35 common brass made with an antimonial brand of copper. These bars were cast 6 ¾ in. wide by 1 in. thick by 45 in. long. In the first pass through the rolls, 19 of the 20 split lengthwise throughout their length, while each half curved outward in a wide arc as it emerged from the rolls. [ ] In those days, if splitting was not a frequent occurrence, it was not unfamiliar. One can recall periods of short duration when large amounts of common brass would behave in this way. There was nothing imaginary about these spells. The affected metal would split lengthwise in the breaking rolls, and no maneuvering of mill practice made any difference. The condition would descend like a plague, demoralize the mill for several days, and disappear. It is doubtful if anyone knew the cause-however many explanations may have been current. In 1921 a quantity of split brass was traced to the use of fired small-arms

Jan 1, 1943

By HAROLD VINTON COES

MANAGEMENT has been tersely defined as getting things done through the efforts of other people; but before we proceed further, let us distinguish between administration, management, and organization. Oliver Sheldon in his book, "The Philosophy of Management," offers the following definitions: Administration is the function in industry concerned in the determination of the corporate policy, the co-ordination of finance, production, and distribution, the settlement of the compass of the organization, and the ultimate control of the executive.

Jan 1, 1943

By H. C. Schultz, F. K. Middleton Hunter

Certain local conditions were known to govern in large measure the successful adaptation of liquid-oxygen explosives to the large-scale blasting at Chuquicamata. The wide variation in hardness of the rock at this mine makes necessary the use of several types of explosives. A locally manufactured, relatively cheap black powder is used in blasting the softer waste and capping material, where a thorough displacement breaks the ground sufficiently. Before the introduction of L. 0. X., an ammonia dynamite of about 65 per cent. strength was being used exclusively in the harder underlying orebody, where a strong disruptive as well as a displacement effect is required for breaking the ore. The L. 0. X., as developed for quarry work in the United States, has a practically pure carbon cartridge material, and the explosive has an extremely high rate of detonation, which should therefore cause it to develop usefully its full disruptive effect in hard ground. The individual blasts at Chuquicamata arc large, black-powder shots which dislodge masses of rock averaging 250,000 tons each, and dynamite shots which dislodge masses averaging 80,000 tons each. It was desirable, therefore, to attempt to displace with L. 0. X. the faster, higher-cost ammonia dynamite used in the smaller blasts. It was not considered practical to attempt to displace the low-cost black powder with 1,. 0. X., as estimated costs showed no probable saving if this were accomplished. Since it was desirable to continue shooting relatively large blasts for effective operation, it was recognized that larger storage facilities than had been in use would be needed for the liquid oxygen. Because of the difficulty of transporting and discharging large storage containers of efficient design, the better plan appeared to be storage and discharge of the liquid at the place of manufacture, and transportation of the filled soaking boxes to the blast. Present Liquid-oxygen Plant An experimental unit with a rated capacity of 75 liters per hour was erected during the latter part of the year 1926 to prove the effectiveness of L. 0. X. at this mine, its cost, and possible efficiency of large-scale storage of the liquid. With this experimental unit 200,000 tons of ore

Jan 1, 1928

By Lucien Eaton

THE use of filling in mines is less common in the United States than it is in Europe, where in some places it is required by law. In most cases the filling is placed by hand, and the material used for this purpose is the waste from development and that sorted from the ore in the stopes. When these sources provide an insufficient supply, additional rock must be quarried on surface or mined underground, or some other material :st be used. In different parts of the world sand, clay, gravel, culm, nulated slag, mill tailings, and even ashes, have been used as filling material in place of or in conjunction with rock. Of all the materials used for filling the best is probably clean sand. Gravel, finely crushed rock, granulated slag and coarse mill tailings are almost as good, and the methods used for placing and confining sand will apply equally well to any of these. The advantages of sand are its comparatively slight compressibility and the ease, economy and convenience with which it may be placed. On account of the voids, which necessarily occur in fills made of coarse waste, such fills will compress 10 to 25 per cent before they develop their full strength, whereas clean sand seldom compresses more than 5 per cent. Sand is especially desirable when practically complete filling is required, and sand derived from mill tailings, especially when not thoroughly cleaned, has been remarkably effective in sealing off and extinguishing mine fires. When natural sand is available on surface, or when it can be obtained from the mill tailings or tailings dump, the cost of using this material for fill will probably be considerably less than that of rock. In this paper it is not proposed to discuss all methods of filling, butt to describe some of the methods used for placing sand fill and to make a brief comparison of their merits.

Jan 1, 1932

By R. A. Hadfield

It seems a specially fitting opportunity to present a paper on the alloys of iron and aluminum at the New York meeting of this Institute, owing to the fact that America has, more than any other country, originated and developed the manufacture of cheap aluminum. The Cowles, Castner, and Hall systems have all originated in the ever-busy brain of our cousin across the water. The problem of cheaply producing this valuable metal has been a difficult one, but to the writer it seems that the more arduous the task the greater the delight with which our American friend attempts to overcome the difficulties surrounding it, and the more vim he throws into the work. Another and equally striking proof of this is to be found in the recent appearance of the already wellknown remarkable work, The Mefallurgy of Steel, by Mr. H. M. Howe, of the Institute of Technology, Boston, Mass. It is to be hopel that this Institute will not be slow to recognize by some special mark its appreciation of this signally valuable and original work. The writer has been led to describe the following experiments, believing that so far no full and exact report has yet been presented to this Institute as to the effect of aluminum alloyed or combined with the metal iron. It has been a special object to make the material as far as possible a true alloy or combination of aluminum and iron, with as small quantities as possible of other disturbing ingredients, such as silicon, manganese, etc. In the material described in these experiments, the total amounts of other elements present (sulphur and phosphorus being disregarded as present in such small quantities) do not exceed about 0.5 per cent. Such material may therefore be probably taken as fairly illustrative of the effect of the metal aluminum upon iron. Since completing the experiments the writer

Jan 1, 1891

By Henry D. Hibbard

I. INTRODUCTION. THESE impurities are perhaps the most important things in steel-especially steel made by the oxidation processes-the effect of which has not been at least approximately determined. By oxidation processes I mean the Bessemer and Siemens-Martin, during which the metalloids in the charge are removed by oxidation. It has been truly said that it is a clear advantage to have a new name for a new thing. To secure this and to economize space, let us adopt the name sonim (plural sonims) to designate the solid non-metallic impurities existing in steel or other metal. I would define a sonim as a solid non-metallic portion of matter existing as an impurity in metal. A piece of sand, brick, clay, or such material, imbedded in metal, would be considered as a foreign body, not as an impurity, and therefore not a sonim. The studies of sonims of which the results have been published hitherto, have been made chiefly or wholly on finished or at least on cold steel, without much, if any, regard to the specific methods by which the steel was made. While many of the results so obtained are valuable, they give little help in determining the cause, effect, or cure of the disease. It is not enough, in such a study, to know merely the commercial name of the process; for within the field of each process lies a great number of possible variations, each of which will yield a result differing in some respect from all others; and the control of sonims is particularly dependent. on the metallurgical treatment of the metal, because of the inability of analytical chemistry to throw much light on their presence, condition, and effect, as they usually occur in commercial steels. The microscope aids more, perhaps, than chemistry in their study.

Apr 1, 1911

By V. E. Christensen

AT most smelting plants, forced draft, induced by high stacks or fans, is used to carry the gases away from the furnaces, roasters, or sintering plants. Gases moving under forced draft carry varying amounts of solids in the form of dust and fume. Where the weight of the solids is material, and the metal content high, it is usually profitable to treat the gases to recover these solids. Baghouses, Cottrell treaters, and settling chambers are the common forms of plants used to recover solids from gases. To check on the efficiency of these plants it is necessary to know the volume of gas leaving the plant and the amount of solids carried by the gas. As the volume of gas is equal to the product of the velocity of that gas and the cross-sectional area of the flue, the determination of the volume includes the measurement of the area of the cross section and the determination of the velocity. The velocity is generally measured by means of the Pitot tube and Ellison differential pressure gage, although low velocities are best determined by means of an anemometer. The dust concentration is determined by passing a measured volume of sample through a filter and weighing the dust caught. From this the dust concentration per unit of volume may be calculated. It is necessary to assume that the gas is homogeneous or that each cubic foot of the gas contains the same weight of dust as every other cubic foot. Having the volume of gas passing through a flue per unit of time, and the dust concentration of the gas per unit of volume, the amount of solids may easily be calculated.

Jan 1, 1935

By Ralph H. Sweetser

N Greenup and Carter counties, in the northeastern part of Kentucky, are the remains of many old charcoal furnaces built and operated during the period from 1818 to 1892. They were all included in what was called the Hanging Rock district. In the summer of 1930 I visited ten of these old blast furnaces, as follows:

Jan 1, 1931

By John H. Walthall, Raymond L. Copson, Travis P. Hignett

In October 1942, the War Production Board requested the Tennessee Valley Authority to undertake investigations to determine the feasibility of producing alumina suitable for reduction in aluminum cells, from clays and other domestic materials, by a lime-sintering, soda-ash leaching process. The work was undertaken by the chemical engineering staff of the Authority under the general direction of the War Metallurgy Committee of the National Academy of Sciences. The investigation included small-scale tests to determine the most suitable conditions for the process, and construction and operation of a pilot plant to obtain data for evaluation of the process and for design of a plant. The results of this investigation are described in the present paper. Sources of Alumina Alumina for the commercial production of aluminum is obtained from bauxite by the Bayer process. The tremendous demand for aluminum for wartime uses is causing rapid exhaustion of the high-grade bauxite deposits in the United States. On the other hand, there is an abundance of aluminous materials such as clay and lower grades of bauxite, which are not suitable for treatment by the Bayer process because of their high silica content. The Tennessee Valley Authority has conducted research and pilot-plant work for more than 5 years on methods for the production of alumina from clay and low-grade bauxite. Particular attention has been given to the high-grade white kaolin found in Carroll County, Tennessee. Exploratory drilling has demonstrated that at least 4 1/2 million tons of kaolin containing in excess of 34 per cent AlzOI is available in this area by strip-mining methods. It has been estimated that hundreds of millions of tons of clay of similar quality occur in the Tennessee Valley region. The Process The process is illustrated in the flowsheet (Fig. I), and consists essentially of the following steps: I. Heating a mixture of clay and limestone to form a sinter containing calcium aluminate and dicalcium silicate. z. Leaching this sinter with a dilute sodium carbonate solution, to form a sodium aluminate solution and a calcium carbonate, calcium silicate residue, which is discarded. 3. Treating the sodium aluminate solution with carbon dioxide to precipitate aluminum trihydrate and regenerate the sodium carbonate solution, which is recycled. 4. Heating the aluminum trihydrate to produce alumina. The process was considered promising because of the abundance and cheapness of the two raw materials, clay and limestone; and because, as compared with an acid process, smaller amounts of critical

Jan 1, 1944

By P. B. Bucky

IN previous publications1 it was shown that a scalar model of any weighty structure, where the stresses produced are mainly due to gravita-tional forces, will behave similarly to its prototype if the model and proto-type material are the same arid the model is placed in a centrifugal field of force (substituted for the gravitational field) which has been increased in the same proportion as the linear model scale is decreased. This principle is now being applied to a study of the behavior of mine structures in an attempt to determine the laws that control them. The importance of using models as a means of solving mining problems has been discussed previously, yet it may be well to reiterate here that this method of research and type of solution have been productive of far-reaching results in other engineering fields, notably those of hydraulics and aerodynamics. Model research is a comparatively cheap and time-saving method of checking practical experience. Up to the present time the best guide to what will happen underground has been the judgment of the man who has observed most and been longest acquainted with the local conditions. His experimental work underground is limited by the elements of cost, time and danger, while failure is seldom permissible. In a model, as in a test tube, all elements that affect the solution of a problem are under definite control. Each element may be varied independently at will and its effects noted. Experimental work on a small-scale model may there¬fore be performed at a comparatively small expenditure of time and money, instead of on a full scale in the mine, where the cost, time, and danger elements are necessarily great. The experiments described in this paper are to be considered as part of a progress report and a continuation of Technical Paper 425. One object of the research program is to make each experiment point the way for further research on that particular phase of the general problem. The results and conclusions presented here are therefore not to be considered as final, but are to be interpreted as

Jan 1, 1933