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Maps and Mining Data for the Library. I suggest that the Institute Library can increase its usefulness by systematically soliciting from the engineers and mining companies all published reports and maps, and parts of reports and records, not of a private or confidential nature. If this is done an engineer assigned to report on a well-known property or district may depend on finding at the library a large amount of preliminary data and general information from these official and engineering reports relating to his prospective investigation. In many mining reports a large part of the report is of a general technical and scientific character, and there could be no good objection on the part of either the engineer, or his client to making such information thus of record. I believe there would be a great deal of information furnished by the engineers if they were properly solicited under this plan. I have found on different occasions that much work could be saved by such records now in the Library. The plan would also have the advantage of keeping the Library in closer touch with the active engineers, a feature to be desired. I also have in mind that the Library should undertake to collect all the prospectuses and financial literature which is issued in connection with mining. Of course a great deal of this is unreliable, but even this is valuable for record in the matter of legal and other investigations. I shall be glad to co-operate with you, and do anything I can to develop more in detail the general ideas above noted. Yours very truly, KIRBY THOMAS NOTE.-The Library of the Institute makes a specialty of collecting and filing material of this character, and the letter printed above is brought to the attention of members in the hope that they will co-operate by sending in copies of maps, reports of properties, etc.

Jan 11, 1913

By B. L. Sackett

IN a general way, the situation in copper smelting is quite similar to that of lead smelting. In other words, the introduction and successful flotation of copper ores has tended to decrease greatly the tonnage to be handled by the smelter and therefore has resulted in curtailed smelter operation. However, copper production has increased rather than decreased. The general effect of flotation has been to decrease the number of furnaces operating, but it has also increased to a considerable extent the difficulties in handling the material, just as was outlined in the case of lead smelting. In copper smelting, the flotation concentrates must be roasted and prepared for the reverberatory furnace. HANDLING FLOTATION CONCENTRATES The handling of copper flotation concentrate, which is more or less wet and mucky, is more difficult than was the handling of the old gravity concentrate. Also, the roasting of the concentrate and the handling of the calcine produced is more difficult. That is mainly because the material is extremely fine and the tendency to higher dust losses is greatly increased. The draft in the roasting furnaces must be kept as low as, possible, and the feeding of the calcine into the reverberatory furnace must be done carefully, so that dust losses may be kept at a minimum. TRANSITION STAGES OF CONCENTRATION AND SMELTING The general process through which the copper smelter has gone as a result of flotation has been somewhat as follows: In the relatively old days, when copper ores of low grade were first treated, a large number of furnaces were required, and naturally comparatively poor recoveries were made. Also, the profits on low-grade ores were small and the handling of those ores was possible only because of the large tonnages. Then came gravity concentration, which was a great improvement but which only incompletely removed the gangue material, the insoluble and the iron, from the copper ore, and made comparatively poor copper recoveries. This still left a considerable amount of insoluble and iron, as well as the copper itself, to be treated at the smelter.

Jan 1, 1928

By Thomas M. Drown

IN the course of some experiments on the analysis of pig iron, I heated, in a platinum crucible, some borings of a graphitic pig iron with sodium carbonate. When the crucible was at a full red heat and the carbonate was thoroughly fused, I noticed a lively ebullition of the mass, and an escape of gas, which burned on the surface. On investigation this gas proved to be carbonic oxide, and on examining the borings in the bottom of the crucible after an hour or two, they were found to be perfectly malleable, although unchanged in general form and appearance. Analysis showed that the carbon was completely removed. I then repeated the experiment, to ascertain whether the silicon and phosphorus were affected, and found that these elements too were largely removed, and could be found in the fused mass as alkaline silicates and phosphates. In order to ascertain whether the removal of the silicon and phosphorus was merely a surface action or whether the reaction really extended into the mass of the iron, I tried the following experiments : A number of bars of pig iron were cast about one foot long and planed down-accurately to one inch section. These were immersed in a large wrought-iron pot full of molten sodium carbonate made by fusing the commercial bicarbonate of soda. Through the kindness of Mr. Frank Firmstone, Superintendent of the Glendon Iron Works, Easton, I was enabled to keep this pot at a reasonably constant high temperature for a long time in one of the hot-blast ovens. One of the bars was removed from the pot every twenty-four or forty-eight hours, according to the rapidity of the action, and after cooling was broken and the fracture examined. The change from pig iron to malleable iron was progressively inwards and always sharp and easily recognized, the rate of progression being in a decreasing ratio with the time. The temperature of the oven had evidently

Jan 1, 1879

By Edwin Ludlow

ONE of the most unusual features in connection with the strike of the union coal miners in the bituminous fields, now in its sixth week, is that the public interest seems to have completely died out. There is nothing on the front page and very little on any other page of the daily newspapers in connection with the strike. The United Mine Workers' officials must be rather disappointed to find that the only way in which they are being featured in the papers at present is in the reports of the trial for treason that is going on in Charlestown, West Va., against the local leaders of that organization for their responsibility in connection with the attack of the miners' army last summer against the non-union mines of Logan and Mingo Counties. Recent reports state that there are 13,000 cars of coal standing on the sidings at union mines for which no billing has yet been found. The output of the non-union mines has been gradually increasing but has never reached the maximum that they are capable of producing, owing to their inability to obtain enough orders to make it possible to run full operating time. The, present output is estimated at, 4,500,000 tons a week. It is possible, with a full car supply and full demand, to bring this output up to approximately 6,000,000 tons per week, and it is very doubtful whether, at this season of the year when probably there is less consumption of coal than, at any other season, the requirements of the country are greater than the 6,000,000 tons which the non-union mines are capable of producing. It would appear, therefore, that there is no immediate prospect of any settlement of the bituminous strike, and there is certainly no reason why the operators of the union mines should show any anxiety to begin operations as long as they have unbilled coal standing on their sidings.

Jan 6, 1922

By Leonard Waldo

PROBABLY some of the views advanced in this paper will appear, from a metallurgical standpoint, little less than revolutionary. It is with considerable hesitancy that I venture to offer a few thoughts concerning what, seems to me to be perhaps the most important development of metallurgy since the introduction of Bessemer steel. Dr. John Percy, with that rare insight which characterizes the epoch-making man, described in a communication to the Royal Society, about 1855, an alloy of duminum and copper which he called aluminum-bronze. The name has "stuck." The term "bronze" has been so variously used that I confess I do not know exactly what constitutes a bronze; but I know that in the great materials of engineering simplicity of composition is a cardinal excellence; and I wish to venture the suggestion that aluminum-bronze is not an alloy of aluminum and copper in any such sense as the compounds of tin and zinc with copper (except the copper-tin compound SnCn3) are alloys. There are several reasons which lead me to this view. In the first place, if a series of bars be prepared containing varying percentages of aluminum and copper, and the electrical conductivity of these bars be carefully determined, a curve of conductivity will be obtained, as shown in Fig. 1, which represents the result of such experiments. While I am not sure, at this time, that the values of conductivity shown in this diagram are wholly dependent upon the percentage of aluminum added, the assumption is a probable one; and the curve indicates that an extremely small percentage of aluminum affects the conductivity in a ratio out of all proportion to the amount of that metal. Another reason is drawn directly from experience in the foundry. If we take from the furnace a crucible containing melted aluminum and one containing melted copper, both at a little more than a red heat, and pour them together, the reaction is so intense that the

Jan 1, 1895

By H. Ries

IN THE marketing of mineral products, it is always highly desirable for both the producer and the consumer to be able to discuss things in a common language, and this can only be done if there are standard methods for expressing the properties of the raw materials. Having developed such a form of expression, the next step would be the making of specifications, which may serve as a basis for selecting raw materials. Considering the large number of non-metallic minerals that are used, there are not a few for which there are no standard laboratory tests to be used in determining their properties, or even standard specifications on which grades or market price may be based. Indeed in many cases the consumer simply requests the producer to submit samples, and rejects or accepts them without any explanation. Could the producer know in advance just what the consumer needed, time and money might often be saved. It appears to the writer that it is of the highest importance to devise standard laboratory tests wherever possible, as this enables the consumer to state definitely what he needs, and is of great assistance to the producer. It should also work to reduce misunderstandings and disputes. 'In the case of sands, we find that they show a wide variation in their character, ranging from those that are so coarse as to be of gravelly nature to those that are so fine that they might be classed as silt; and from very clayey ones to those that are practically free from clay. For this wide range of sands, we have a corresponding variety of uses, which are based mainly on the physical properties of the sand, although these are not always very definitely stated. The chemical composition need rarely be considered, if the sand is of siliceous nature. To determine and express these properties there should be standard tests, which are to be followed in all cases where the material is tested in the laboratory.

Jan 1, 1926

By G. Czupryna, S. Natansohn

Electrowinning is the prevalent technique for recovering silver from wastes generated in silver-tungsten electrical contact fabrication. Such scrap is placed in a permeable plastic basket, which constitutes the anode compartment, and is suspended in a larger cell where the cathode is mounted. A silver nitrate solution is used as the electrolyte and, upon application of an electric field, the silver migrates to the cathode where it deposits. At times, there is tungsten migration to the cathode compartment and consequent co-deposition with the silver. This W contamination, which may amount to several thousand mg/L (oz per gal), necessitates additional purification of the deposited Ag and its removal would, therefore, be advantageous. Eliminating the W impurity also extends the operating period of the cell with corresponding increases in the Ag output and savings in labor costs. The solution to this problem lies in the selective removal of the W from the AgNO3 electrolyte either by liquid-liquid or liquid-solid extraction. Although W extraction in the liquid-liquid mode with a quaternary amine or other reagents as extractants appears feasible, particularly in view of the low pH (about 1.5) of the system, this approach was not considered because it is essentially a batch-type process. It is a more elaborate industrial operation than extraction by ion exchange resins. Implementing the latter process consists of passing the electrolyte from the electrowinning cell through an ion exchange column which would extract the tungsten selectively and returning the tungsten-free stream to the cathode compartment. This process continues until the W extraction efficiency decreases (as a result of resin loading) below an acceptable value. The electrolyte is then directed through another, similar column while the W values are eluted off the first one and the resin is regenerated for another cycle. Thus, two columns in a parallel flow pattern provide the means for continuous processing of the electrolyte feedstock.

Jan 1, 1984

By H. M. Howe

One of the little electric-resistance magnesia crucible-furnaces which I designed for the metallurgical laboratory of the School of Mines of Columbia University is shown, in vertical section, of full natural size, in Fig. 1. The furnace itself consists of two semi-cylinders of magnesia, A A, with a cover of magnesia, B B, and a stopper, C, also of magnesia, which is perforated to admit the leads x, y, of a thermo-electric couple. The furnace is heated by the spiral of platinum wire, D D (entering and departing by the openings I and K), through which a current of any desired strength is passed, bringing it to incandescence, and to ally temperature, not above the melting-point of platinum, which may be desired. The crucible E, actually used in this furnace, is also of magnesia. I have heard of some unsuccessful attempts with furuaces of this general class, and have attributed these failures to the use of siliceous materials for the furnace-walls. Of course such a result is what we should expect, since the silica mould readily be electrolysed by the current, and the resultant silicon would alloy with platinum ; but the little magnesia furnace here clescribed seems to be wholly free from this objection. It has been used in my laboratory for some months, and temperatures, up to 1100° C, hare been developed in it over considerable periods of time—indeed, it has been held near 1400" C. for about two hours—without indication, thus far, of any deterioration of the platinum. In the section shown, F F are a pair of steel disks, bound together, but separated by the inverted thermo-junction, N, of the thermo-electric pyrometer. This arrangement permits the observation and record of retardations in the heating and cooling of F F—in other words, the determinations of the cooling curves of steel—a purpose for which the furnace has been used, thus far, more frequently than in the determination of meltingpoints. For the latter operation, however, it is also suitable.

Jan 1, 1902

By Walter Larsh

The Ruth orebody, so far developed, is roughly oval in plan, major and minor axes about 1600 ft. (487 m.) and 1200 ft. (365 m.) respectively, average thickness about 120 ft. (36 m.), and with a general dip of about 15° to the northwest. According to the generally accepted theory, the ore is a secondary enrichment of the porphyry due to leaching in situ by meteoric waters. Copper occurs as chalcocite, chalcocite coating pyrite, and a little chalcopyrite. The leached zone, or capping, covering the ore varies in thickness from 110 to 540 ft. (33 to 164 m.), average about 410 ft. (124 m.). The ore is blue gray in color, and the capping, light yellow to brown. Ore was first discovered in quantity in the workings from the Ruth shaft, now caved. Further development work was done by churn drills, and the outline of the orebody, as stated above, determined in this manner. Drilling is still being carried on. The porphyry area is entirely surrounded by sedimentaries, lime-stones and shales; and, in so far as the underground workings have shown, the porphyry' itself, the sedimentaries near the contact, and the country underlying the ore (igneous or sedimentary) is very soft, heavy, and in places swelling ground. All openings have to be carefully and stoutly timbered, and, after once driven, they have to be constantly eased off and repaired. The mine is at present served by two shafts, the Star Pointer, the main working shaft; a vertical, and the Ingersoll, an incline used for waste and material. The two shafts are about 2600 ft. (792 m.) apart, connected on the 500 level; a connection is now being driven on the 600 level. (Dec., 1917. This connection is now completed.) The 300 level, which is finished, and the 400 level which is nearly completed, are accessible only from the Ingersoll and connections with the 500 level.

Jan 1, 1918

By G. L. Craig

COPPER containing a small amount of arsenic has been used extensively abroad, and a number of reports, particularly those by English workers, have indicated that such copper is better suited for certain uses than high-conductivity copper. Inasmuch as a large percentage of the copper fabricated is used for nonelectrical purposes where high conductivity is not at all essential, it has been suggested that arsenical copper might be at least as suitable as high-conductivity copper for many purposes. An investigation spon-sored by the Calumet & Hecla Consolidated Copper Co. at Battelle Memorial Institute was therefore undertaken with the object of determin-ing the effect of small amounts of arsenic (up to 0.75 per cent) on the properties of copper. In this work the effect of arsenic on the basic properties of tough-pitch and of phosphorized copper have been critically studied and many data collected from laboratory experiments which have been supplemented by mill-scale tests. The results of these tests, with coppers of the type referred to, in the annealed condition and after various degrees of reduction, show that the basic properties of copper are not greatly affected by small amounts of arsenic, an increase in strength being observed with increasing arsenic with no corresponding decrease in ductility. It is well known that the evaluation of material for plastic deforma-tion, on the basis of laboratory tests, may not be directly comparable with its performance in commercial operations. In order, therefore, to substantiate the data obtained at the Institute, the cooperation of the Wolverine Tube Co. was obtained for a series of production tests on the fabrication characteristics of phosphorized arsenical copper in the manu-facture of seamless copper tubing. In these tests the behavior of the arsenical coppers was carefully observed in comparison with that of representative types of phosphorized arsenic-free copper, which were fabricated under the same conditions.

Jan 1, 1933

By Thomas M. Drown

In the course of some experiments on the analysis of pig iron, I heated, in a platinum crucible, some borings of a graphitic pig iron with sodium carbonate. When the crucible was at a full red heat and the carbonate was thoroughly fused, I noticed a lively ebullition of the mass, and an escape of gas, which burned on the surface. On investigation this gas proved to be carbonic oxide, and on examining the borings in the bottom of the crucible after an hour or two, they were found to be perfectly malleable, although unchanged in general form and appearance. Analysis showed that the carbon was completely removed. I then repeated the experiment, to ascertain whether the silicon and phosphorus were affected, and found that these elements too were largely removed, and could be .found in the fused mass as alkaline silicates and phosphates. In order to ascertain whether the removal of the silicon and phosphorus was merely a surface action or whether the reaction really extended into the mass of the iron, I tried the following experiments : A number of bars of pig iron were cast about one foot long and planed down 'accurately to one inch section. These were immersed in a large wrought-iron pot full of molteu sodium carbonate made by fusiug the commercial bicarbonate of soda. Through the kindness of Mr. Frank Firmstone, Superintendent of the Glendon Iron Works, Easton, I was enabled to keep this pot at a reasonably constant high temperature for a long time in one of the hot-blast ovens. One of the bars was removed from the pot every twenty-four or forty-eight hours, according to the rapidity of the action, and after cooling mas broken and the fracture examined. The change from pig iron to malleable iron was progressively inwards and always sharp and easily recognized, the rate of progression being in a decreasing ratio with the time. The temperature of the oven had evidently

Jan 1, 1879

By A. F. Banks

INTRODUCTION Selective flocculation-flotation as a method of desliming potash flotation feed has been practiced in the Cominco Ltd. potash plant since November. 1974 when it was installed to replace a less efficient mechanical desliming process. The plant was designed for a consistent feed containing 4.5% insolubles. In practice the quantity and quality of the insoluble material is quite variable. This variability led to serious problems in the deslime circuit and consequently had an adverse effect on sylvite flotation performance. A costly mechanical solution to the problem was being seriously considered when it was drawn to our attention that a selective flocculation-flotation process had been developed. The process was tried first in the laboratory on the Cominco Ltd. ore, then on a pilot basis on 25% of the mill feed and finally full scale. The time from being informed of the process to full scale operation was 18 months. It has since been incorporated into a tailings regrind circuit. The original mine design called for the mining of an 11 foot height up to the top of the three clay seams. These had to be taken as they were a zone of structural weakness. It also assumed that the beds would be uniform with only a few disturbances. Very soon after the initial start up it was found that permanent openings had to take in the layers right up to the upper clay seams and because of the mining process that this material would have to be milled when encountered. The number of disturbed areas in the mine is greater than the design anticipated. In operation the insoluble content of the mill feed varies from 4.5% to 8% plus with the peaks being very short- term to relatively long, from hours to day. In terms of quality, the insolubles in the mining horizon are relatively soft and easily liberated, whereas those above are hard and liberate slowly.

Jan 1, 1979

By C. W. A. Newey

I would like to make the following points in connection with the studies of the deformation of NiAl reported in the recent paper by Wasilewski, Butler, and Hanlon. 1) Much of their paper is concerned with demonstrating that slip occurs on either {110)(001) or {100)(001) systems. In their discussion they state "the existence of (001) as the basic slip direction can thus be considered established." This fact was established by the earlier studies of Ball and Smallman.32 Ball and Smallman also concluded that the slip plane was of the type (110) and they showed that cross slip or pencil glide on orthogonal (110) planes could produce macroscopic slip on planes of the (001) zones, e.g., (100). Wasilewski et al. refer to this paper by Ball and Smallman but not in connection with the slip system determinations. 2) Wasilewski et a!. eliminate the possibility of (111) slip in NiAl on dubious grounds. Their statement that ('the very high yield strengths of the (100) oriented crystals", in which (001) slip is constrained, "immediately ruled out the possibility of {110)(111) slip" cannot be accepted unequivocably; it would be reasonable if the crystals were completely brittle but they are not, as Wasilewski et al. and others33734 have shown. Their elimination of the possibility of (111) slip in a crystal compressed along [227] is misleading since there is no obvious reason why (111) slip should occur in a crystal of this orientation. In fact, from an analysis of the macroscopic surface markings on deformed (100) stoichiometric crystals, Pascoe and Newey34 have deduced that slip occurs on systems of the type {211)(111) and {321)(111). 3) Polycrystalline NiAl is known to undergo general deformati~n.Having emphasized that general deformation is impossible if only (100) slip occurs, it is a pity that Wasilewski et al. do not attempt to account for the disagreement between theory and their experimental results. Of course, (111) slip can provide the additional independent systems required for general deformation.

Jan 1, 1969

By Arthur Notman

THE matters I had intended to present to you ap-peared in the March 12 issue of Engineering and Mining Journal over the signature of George J. Young, so that although I should like to talk to you for about three hours on this subject, unfortunately it has all been done before. The subject originally sug-gested to me was the trend in mining methods. You will find that fully set forth much more clearly than I could hope to do, in Mr. Young's article, so that I shall confine my attention to a few points of interest in specific cases. You are undoubtedly familiar with the problem that was presented to the Miami Copper Co. when they had exhausted their so-called high-grade orebody. They had what appeared to be a large tonnage of material which their preliminary development work and such drilling as was done indicated contained one per cent copper or a-little over, and how to mine that profitably by underground methods was the question. It was somewhat complicated by the fact that the nature of the ground made them doubtful of their ability to cave it successfully. It was unquestionably harder ground than that of the more highly mineralized sections of the Miami and Inspiration- ore zone which had been mined. However, they had kept very accurate and complete records of past accomplishments and knew what they had to work with and what modifications with respect to costs would be necessary in order to solve this problem. Under the old method of working, they were extract-ing about 71/2 tons per man employed in the mining department; that is to say all labor, direct and indirect required to put the ore in the mill bins, and this, with the grade of ore which they had, resulted in a satis-factory financial outcome. Under their modified method now in use, they have raised that output per man to 29 tons per man shift. That is almost four times what they were doing with the old method.

Jan 4, 1927

By Morris Muskat

In preparing a well for pumping, observations are often made of the fluid level in the well bore or bottom-hole pressures at various times before equilibrium has set in. From a qualitative point of view one may immediately infer that if the rise in the bottom-hole pressure or fluid level is rapid the permeability of the sand about the well bore is large, and converse conclusions may be drawn if the rise is slow. However, a more quantitative estimate will give additional information of value, as will be shown in this paper. To derive such an estimate we may proceed as follows. Let h be the fluid height, above the sand face, at time t, and let yo be the average density of the fluid that enters the bore. The bottom-hole pressure, for a fluid height h will therefore be p = rogh, neglecting, of course, the friction drop in the well bore, while the fluid is rising, as may be justifiably done for most pumping wells. If a is the free area of the open-flow string—assumed to be uniform— the rate of production from the sand during the rise of fluid will be: where the last part of the equation merely indicates that, in general, the production rate Q must be considered as a function of the back pressure, and is determined by it alone. In fact, equation 1 shows that if the rate of rise of the pressure or fluid level is determined as a function of the height of rise, or p, for a number of values of the latter, this functional relation between Q and p will be immediately given. Conversely, if we know this functional relation, the rate of increase of p or h may be predicted, or, by observing the rate of rise of p or h some of the constants of the sand may be determined. Thus we may approximate the production from a well in a pumping state by that of a dead

Jan 1, 1937

By J. L. Gissy, G. H. Schippereit, J. B. Schroder

THE existence of mechanical anisotropy in hexagonal metals is well known.' One possible method of measuring the degree of anisotropy in a metal is to make hardness measurements on the different planes of a single crystal. So far as is known, no single-crystal hardness data have been reported in the literature for alpha titanium. To obtain an estimate of the variation in hardness with crystallographic direction in titanium, Knoop hardness measurements were made on single crystals of electrorefined alpha titanium obtained from the Bureau of Mines, Boulder City, Nev. The hardness of arc-melted ingots prepared from this material was 64 Bhn (1000-kg load, 30 sec). Crystals of sufficient size were mounted in epoxy resin with the basal plane exposed. They were then polished and etched to remove excess plastic resin and work-hardened surface material. The crystals were then examined by x-ray diffraction, using the back-reflection Laue technique to insure that the crystals were properly oriented and strain free. After Knoop hardness readings (100 or 200-g load) were taken on the exposed surface, the crystals were remounted to expose a prismatic face and the foregoing procedure was repeated. Hardness values for various orientations are listed in Table I. The data show a difference between the hardness of the basal planes and that of the prismatic planes, as anticipated. More striking is the hardness difference observed between different orientations of the indentor on the prismatic planes as shown in Table I and Fig. 1. All of the indentations shown in Fig. 1 were made with a 100-g load. The long axis of indentation A is parallel to the unique (c) axis of the crystal. The deformation marks visible around indentations A and C of Fig. 1 are probably slip traces of the (10.0) system reported by Rosi, et al. The greater hardness observed when the long axis of the indentor was perpendicular to the unique axis of the crystal (indention B) is probably caused by the opera-

Jan 1, 1959

By J. W. Turrentine

SECONDARY fertilizer minerals include borax, gypsum and sulphur and such compounds as the sulphates of copper, magnesium, manganese and zinc; also the carbonate and oxide of magnesium. Potash, phosphates and nitrogen are generally considered to be primary fertilizer materials. The growing plant, under the average conditions of growth, is able to get from the soil the mineral elements required for the completion of its life cycle. The elements taken up are numerous and the vital functions of some of them yet remain to be determined. However, in the commercial growing of the plant (farming) something much more than the mere completion of a life cycle is required. There the maxi- mum possible growth of plant or yield of seed or fruit are the objective and for that objective the average soil is deficient in some elements, and additions from artificial sources are desirable. Commercial fertilizers (15,000,000 tons in 1946) are designed to supply those deficiencies. Long experience has taught that nitrogen, phosphorus, and potassium are the elements most apt to be required and in a greater degree, and to supply them is the-basic function of the fertilizer industry. Thus nitrogen, phosphate, and potash are designated as the major plant-food materials. But other mineral crop nutrients may likewise be deficient in varying degrees as determined by diagnostic techniques, soil tests, plant analysis and foliar symptoms,3 calling for their addition from artificial sources if maximum crop yields are to be obtained. Because used in lesser amounts and frequently in relatively minute amounts as compared with the major three, they are designated either as "minor elements," or, if used in larger amounts, as "secondary elements." Thus, included under the two designations, in alphabetical order, are: borax; copper sulphate; magnesium carbonate, oxide and sulphate; manganese sulphate, and zinc sulphate. Obviously, the sulphates of the metals copper, manganese, and zinc cannot be considered as "industrial rocks," but they are given brief mention for whatever interest may pertain there to.

Jan 1, 1949

By C. P. McCormack

THE Cuyuna manganiferous iron ores can be a principal source of manganese for the iron and steel industry in the United States, provided metallurgical methods as a whole are adjusted so as to use run-of-mine ore. The use of manganese in steelmaking is growing. Increasing amounts of impurities in raw materials call for more manganese, a constant cheap supply of which is wanted. There are few deposits of ore in the United States carrying over 35 per cent. manganese that can be mined and marketed at a profit in normal times. We are largely dependent on foreign ores. The small domestic deposits should rightly be held in reserve for an emergency, such as a war, when importation might cease. Even the production from lean ores, concentrated it may be, might not carry us through a protracted stringency. The Cuyuna district is, therefore, during normal times capable of supplying a large total of manganese. The ores are iron ores containing 5 to 25 per cent. of manganese with the inverse range of 52 to 28 per cent of iron. The manganese costs no more per unit in the ore than the iron, because cost of mining, largely by open-pit methods, is not affected by the manganese content. The manganese units should, perhaps, command a higher price, but as their value is contingent on metallurgical practice, a higher price may be justified only when a shortage in manganese occurs. Manganiferous iron ores can never entirely supplant straight manganese ores though methods are employed that will permit them to do so partly. For the manufacture of ferromanganese, ores carrying above 42 per cent. manganese are needed. Ores with manganese running between 20 and 42 per cent. are used for making spiegeleisen. But established practice in certain plants, based on the admixture of manganiferous iron ores to straight iron ores has greatly lessened the consumption of high-priced, scarce, manganese alloys with good results.

Jan 2, 1925

By H. M. Merry

The graphic methods and records described in this article have been developed, with satisfactory results, for the use of executives of the Chino Copper Co., in Hurley, N. Mex. Particular attention is directed to the use of large wall-charts, the quick reference display of large charts, the scale notation of metallurgical charts shown in Pig. 3, and the inclusion of mesh extraction on screen analysis diagrams. To properly comprehend the operation and metallurgical results from a concentrating plant, a daily record of essential data is kept, usually involving the dry weight of ore milled or treated, dry weight of concentrate or metal produced, assay values of heading, assay values of tailing, assay values of concentrate, and percentage of extraction or recovery. In addition it is often necessary to record moisture, pulp density, or dilution, percentage of weight of oils and reagents employed; screen analyses of grinding conditions, oversize, etc.; assay values of non-valuable or interfering substances; cost data; and such special information as may be required. GRaphic Presentation . Close analysis is necessary of a daily operation involving such a number of factors, the relation and influence of which may be of great importance in the treatment scheme. When the analysis is made from a numerical tabulation, the chance for one or more obscure, but perhaps important, factors to escape notice is considerable, therefore the need for an accurate, readily digestible presentation of metallurgical data is obvious.. Graphic records of milling operations are frequently used, but owing to the wide range of magnitude and values, and the number of factors involved, the customary practice of assigning different values to the same ordinates, as in Fig. 1, results in a complex and intricate record which makes little appeal to a busy operating official. The methods shown in Figs. 2 and 3 are devised to display such data in a clear and legible manner, without confusion.

Jan 1, 1920

By H. W. Paxton, G. M. Pound

A method is outlined for taking into account variation in chemical potential of both components in evaluating capillary effects at growing interfaces. The results are compared with experiment, and seem to be in reasonably good accord for Widman-statten ferrite growing in austenite. ENERY pointed out that during the steady-state growth of phases with a rather small radius of curvature at their advancing edge capillarity cannot be neglected. By proper application of the Laplace equation a correction must be made to the activity gradients down which diffusion occurs. Subsequent workers have concerned themselves with attempts to evaluate specific cases by the use and modification of the principles laid down by Zener.2-5 To solve the problem in its simplest form it is necessary to assume thermodynamic equilibrium at the interface and to select some criterion which will allocate the available free energy between reversible and irreversible processes. Zener chose to assume that the division should be made such that the new phase grew at the maximum rate. Other workers have used the same2,3 or different assumptions, e.g., maximum rate of free-energy dissipation,4 minimum rate of entropy production.5 Li6 has proposed that the "thermokinetic potential" should be a minimum at steady state. The purpose of this presentation is to note that most prior treatments have considered variations due to capillarity only in the chemical potential of the mobile constituent, and that a more consistent treatment must involve a consideration of the variation of chemical potentials of both solute -and sol- vent in a binary system.* As an example, the way in which this arises for ferrite growing from austenite may be illustrated by reference to Fig. l(a). The line OABC shows a typical variation of carbon activity with composition at one atmosphere pressure (at a transformation temperature below A3). In the tip of a growing ferrite plate with a hemi-cylindricab leading edge of radius ?, the pressure due to capillarity is*

Jan 1, 1963