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Alfred Stansfield, Montreal, Canada:—In Professor Howe's paper on the position of Ae3, he shows its industrial importance in determining the temperature to which steel should be heated for " grain refining." Several years ago I carried out a research on the " burning " of steel and found that while hypo-eutectoid steel should be heated to Ae3, hyper-eutectoid steel that has been very much overheated must be reheated to the curve Sa on the carbon-iron diagram, in order to redissolve the pro-eutectoid cementite and thus to obtain recrystallization and grain-refining. This treatment was necessarily only partly successful, and I should like to ask whether the conditions of heat treatment for refining overheated high-carbon steels have been ascertained. Speaking of the &'Persistence of Solidificational Segregation " Professor Howe quotes an experiment made by Mr. Stead in which a bar of 1.2 per cent. carbon steel was immersed in a large mass of molten blast-furnace slag and allowed to cool with it. The steel was heated ; above the solidus (curve An on the carbon-iron diagram), but below the liquidus (curve AB). A drop of eutectic carbon-iron alloy, rich in carbon, had liquated out and hung below the bar. This agrees exactly with my own observations on the burning of steel, but my interpretation differs somewhat from that of Professor Howe. Professor Howe considers that the fusion of a part of the metal (rich in carbon) shows that the solidificational irregularities of composition had persisted through the rolling and heat treatment of the steel, as otherwise no part of the steel would have been sufficiently fusible to melt. It does not appear to me that such an explanation is necessary. A piece of steel represented in temperature and composition by any point within the area ABa will ultimately resolve itself into a solid phase and a liquid phase in equilibrium with each other. It may appear that if the steel were absolutely uniform no fusion could take place, but, the smallest nucleus of high-carbon, fusible alloy would ultimately bring about this separation into liquid and solid phases, by diffusion of the carbon from the solid to the liquid areas. A nucleus sufficient for the purpose might be provided by an area of pro-eutectoid cementite which had not become diffused during the

Jan 1, 1914

By Eckley B. Coxe

I DES~RE to call the attention of the Institute to two deep vertical shafts, which are now being sunk in Schuylkill County, Pennsylvania, about miles north of Pottsville. These shafts are of interest to the mining engineer, not only on account of the novelty of the method of sinking adopted, which promises to produce a revolution in that branch of mining engineering, but also as examples of the manner in which such work should be undertaken. GEOLOGICAL SKETCH OF THE TERRITORY TO BE WORKED BY THE SHAFTS AND REASON FOR SINKING THEM. The Mammoth or E Vein of the anthracite coal-measures in that part of the Schuylkill region near and north of the town of Pottsville lies at a great depth below the surface, and has, in consequence, never been worked in that locality.

By James W. Guider

Of all the technology available to the iron blast furnace operator, raw materials preparation [(Fig. 1)] is by far the most important. Superior raw materials have been basic to the success of the Japanese steel industry, and they are just as essential to the American steel industry in winning its competitive battle against foreign government subsidized steel imports. Therefore, the mine operator and the ore beneficiation engineer must strive to produce the highest quality raw materials possible to meet the precise demands of the modem blast furnace and steel plant.

Jan 1, 1982

By E. C. Harder

The situation in the United States, at the present time, regarding the supply of manganese ores and alloys of manganese is one of great seriousness and is likely to become increasingly so while the European war continues. The two principal iron-manganese alloys, ferromanganese and splegel-eisen, are indispensable in steel manufacture, being used extensively in the Bessemer and open-hearth processes. Spiegeleisen, the lower alloy, contains between 15 and 25 per cent., and ferromanganese, the higher alloy, between 60 and 80 per cent., of manganese. Besides manganese the alloys contain iron and carbon. On the market ferromanganese is usually quoted on the basis of 80 per cent. manganese, and spiegeleisen on the basis of 20 per cent. manganese. The consumption of ferromanganese has been increasing during recent years at the expense of spiegeleisen, because larger quantities of the latter must be used to accomplish the same purpose with the result that the amount of carbon introduced with it into the molten metal is frequently injuriously great. Manganese ore proper, in the form of manganese dioxide, is used extensively in many chemical industries, especially for oxidizing purposes. It is also used for the manufacture of both wet and dry electric cells and in the manufacture of paints and dyes. The manganese ore used in this country has been derived hitherto from three principal sources: Southern Russia, Southern British India and East Central Brazil. The following tables show the quantity of manganese ore imported from these countries, and (for comparison) the domestic production, during 1912, 1913 and 1914. The imported manganese ore has been used largely in the manufacture of iron-manganese alloys and in addition large quantities of the alloys themselves have been imported, chiefly from Great Britain, Germany and other European countries.

Jan 1, 1917

By Charles H. Shamel

I fear most of the Institute members are already weary of the perennial controversy about the apex law. I feel that way about it myself now, though I have been guilty of considerable contribution- to the discussion in the past. The discussion does not seem to perceptibly influence previously held views and I would not again break into print on the subject but for the urgent invitation of the Chairman of our Law Committee. This energetic and able member has firmly determined to secure a revision of the mining law and among other things to eliminate the so-called apex provision from the U. S. mining statutes. He is, however, fair about it and has invited me to make ((the strongest possible argument in its favor." I am suspicious that he is acting on the psychological principle that it is usually easier to convince an audience against a cause vigorously but unsuccessfully defended than against one wholly mute. Nevertheless, I realize that personally he wishes me no harm, much as he hates the apex law, and so am willing that the Institute have whatever benefit may accrue from my taking up again the unpopular side of the discussion. I say this because the attitude of a large part of our "articulate" membership seems irreconcilably hostile; their minds are made up; favorable consideration is foreclosed; and they become impatient and even sarcastic at any attempt to elucidate a favorable view of the apex law. The exact question for discussion at the present time is not whether on abstract, or any other considerations, the apex law is the best possible rule, but the very different proposition whether, after nearly 50 years of statutory life and much longer as a practically universal miners' custom, it is now just and expedient to repeal the apex law. At this point it seems to me that we may profitably devote a paragraph or two to the subject of the origin of law in general, as we are presumed to be considering the subject from the high viewpoint of the general welfare of the nation. The most comprehensive and accurate definition of law in the legal sense is, that it is the body of rules for the regulation of human conduct which is enforced by the State, that is, by the nation.l Legal

Jan 1, 1915

By C. G. Grant, Wm. B. Price

This investigation of low copper-nickel silvers was untiertaken to check the work of Lèon Guillet on special brasses and to determine, more accurately, the effect of the addition of nickel on the mierostructure of the binary alloys of copper arid zinc. It was hoped that the results could be successfully applied to the practical production of low copper-nickel silvers. To explain the results of his investigations on special brasses, Lèon Guillet evolved his conception of "fictitious compositions." He states,' in his general conclusions, that on the introduction of a small amount of a third metal to a copper-zinc alloy, it enters into solid solution with the normal constituents up to saturation, but by so doing it brings the ternary alloy into a state microscopically equivalent to a binary copper-zinc alloy of fictitious composition, and physically more nearly like the latter than the brass containing copper-zinc in the ratio actually present. The physical properties of the ternary alloy, when compared to the same properties of an actual brass of the fictitious composition, are modified by the natural properties of the third element. Beyond the point of saturation, a special constituent appears and the above generalization no longer holds. For example, if a 60:40 brass has 4 per cent. of tin substituted for 4 per cent. of zinc, the actual composition would analyze 60:36:4. Assuming that 1 per cent. of tin plays the same part as 2 per cent. of zinc, the proportions of copper and equivalent zinc may be stated as 60 parts of copper and 44 parts of zinc, which, figured to 100 per cent., gives an analysis of 57.7 per cent. of copper and 42.3 per cent. of zinc, the fictitious composition for a 60:36:4 tin brass. The relation between ternary alloys containing copper and zinc together with a third metal, and the microscopically equivalent binary alloy of copper and zinc, may be expressed mathematically.

Jan 1, 1924

BENEFICIATION AND CONCEN'TRATION; FROTH FLOTATION U.S. 4,069,144 - In the froth flotation beneficiation of phosphate rock using at least an acid flotation step and an amine flotation step, the crude ore is dried either during transport or storage or by air circulation immediately prior to classification, and the dried ore mixed with water and classified prior to flotation The preliminary drying substantially eliminates the usual problems with clay slimes G. C. Johnson and A. E. Schweizer, assigned to Mobil Oil Corp. Jan 17. 1978. 4 pp (209- 11) . Filed 1 1-19-75 (633,535).

Jan 1, 1979

By William P. Blake

Postscript to the paper read by Prof. William P. Blake at the Lake Superior meeting, September, 1904. POSTSCRIPT.*-Since the publication of my paper upon the blackening of the surface of rocks in desert regions, I have noted that similar views of the origin of superficial discoloration in the case of certain rocks from the Salt Lake basin of Utah have been expressed by Prof. George P. Merrill. In the pamphlet, he described the brown-coated weathered boulders from Tooele county, reaching the conclusion that the discoloration was due to the solution of the manganese and iron compounds 'in the interior of the boulder, while they were in the water, and the gradual bringing of this material to the surface through capillarity and its oxidation when exposed.

Mar 1, 1905

By Henry M. Howe, Joseph Winlock, Francis B. Foley

This investigation was undertaken for the purpose of determining, in a systematic way, the effect of the rate of cooling of steels, heated to above the transformation range, on their various mechanical properties. This paper gives the results obtained in the investigation of the heat treatment of carbon steels carried out under the auspices of the Committee on The Heat Treatment of Carbon Steels of the Engineering Division, National Research Council. The objects of this committee, of which Dr. Henry M. Howe was chairman, were to increase knowledge of the influence of heat treatment on the mechanical properties of carbon steel. The mcthod pursued was to subject specimens of steel of the carbon contents most used for engineering work, 0.34 per cent., 0.52 per cent., and 0.75 per cent., to various heat treatments, and to test the mechanical properties thus induced. The steels were the same as were used by the committee on fatigue phenomena. This project was financed jointly by the U. S. Bureaus of Mines and Standards; industries and university laboratories have cooperated. A large part of the work was done at Doctor Howe's private laboratory. The committee consisted of F. B. Foley, H. AT. Boylston, H. C. Boynton, G. K. Burgess, H. J. French, J. H. Hall, Zay Jeffries, R. S. Johnston, F. C. Langenberg, H. F. Moore, E. H. Yeirce, H. S. Rawdon, W. E. Ruder and 11. J. Stagg. The work was undertaken at the suggestion of Doctor Howe, who thought, at the outset, that steel in the sorbitic state might have properties which, for most engineering purposes, would be better than those of the usual or pearlitic state. By a systematic variation in the heating

Jan 1, 1923

By Joseph Winlock, Francis B. Foley, Henry M. Howe

This investigation was undertaken for the purpose of determining, in a systematic way, the effect of the rate of cooling of steels, heated to above the transformation range, on their various mechanical properties. This paper gives the results obtained in the investigation of the heat treatment of carbon steels carried out under the auspices of the Committee on The Heat Treatment of Carbon Steels of the Engineering Division, National Research Council. The objects of this committee, of which Dr. Henry M. Howe was chairman, were to increase knowledge of the influence of heat treatment on the mechanical properties of carbon steel. The mcthod pursued was to subject specimens of steel of the carbon contents most used for engineering work, 0.34 per cent., 0.52 per cent., and 0.75 per cent., to various heat treatments, and to test the mechanical properties thus induced. The steels were the same as were used by the committee on fatigue phenomena. This project was financed jointly by the U. S. Bureaus of Mines and Standards; industries and university laboratories have cooperated. A large part of the work was done at Doctor Howe's private laboratory. The committee consisted of F. B. Foley, H. AT. Boylston, H. C. Boynton, G. K. Burgess, H. J. French, J. H. Hall, Zay Jeffries, R. S. Johnston, F. C. Langenberg, H. F. Moore, E. H. Yeirce, H. S. Rawdon, W. E. Ruder and 11. J. Stagg. The work was undertaken at the suggestion of Doctor Howe, who thought, at the outset, that steel in the sorbitic state might have properties which, for most engineering purposes, would be better than those of the usual or pearlitic state. By a systematic variation in the heating

Jan 1, 1923

By AIME AIME

AMONG the members of the Institute there are thirty-three who have been members for a half- century or-more Some time ago a professor of psychology made a careful study of a group of unusually brilliant children to determine whether there was any truth in the general belief that a brilliant mind is usually to be found in a physically sub-normal body. He definitely proved the exact opposite and it is now known that children who are above the average in mental capacity are also above the average in physical health and strength.

Jan 1, 1929

By G. K. Burgess

§ 22. THe results published in Professor Howe's paper10 of our determinations on the Ac3 and Ar3 points for a series of commercial carbon steels " containing manganese in varying proportion, represent the average temperatures found by taking several (4 or 5) heating and cooling curves. The accompanying curves, Figs. 6 and 7, are, for each steel, the first heating and cooling curves as obtained by the inverse-rate method of Osmond, using a cylindrical chronograph sensitive to 0.1 sec. for recording time. Simultaneous observations were also taken by the differential method with a platinum neutral and plotted by Rosenhain's derived differential method and gave substantially the same results, the curves having sensibly the same contours in both cases.12 The observations were taken in vacuo on cylinders 5 by 1 in. in length bored to center with a 1/8-in. hole to receive porcelain insulated thermo-couple, and inclosed in an out- and in-glazed Berlin porcelain tube heated electrically by platinum foil wound on the tube. The vacuum was usually better than 0.1 mm. The heating and cooling of the furnace was automatically controlled by a salt-water rheostat with shaped electrodes, giving a uniform rate of heating and cooling.

Jan 1, 1914

By Donald V. Fites

In the face of an increasing demand for minerals, the resulting technological developments, and rising overburden-to-ore ratios, many open-pit mines now incorporate totally different concepts for the removal of ore and overburden. Moreover, under a growing number of these concepts, wheel tractor scrapers are being assigned a major role in material- handling systems for unconsolidated overburden removal. To say that scrapers move only unconsolidated overburden is incorrect. On the contrary, ripped phosphate rock, copper ore, iron ore, and moderately consolidated overburden are also being moved by scrapers in various areas of the world. According to the Minerals Yearbook, about one half of the material moved in metal and nonmetal mines is never drilled, blasted or broken by other means. Scrapers Find Wider Application The increased use of scrapers in open-pit mining today is due in part to improved design which has endowed these units with added versatility and in- creased their production capability. The modern scraper, which is designed as a loading and hauling vehicle, cannot be compared to the original tractor- drawn scrapers which were limited in capacity, maneuverability, and speed. Improved design of the scraper bowl ejection system has aided production. Gravity ejection has been replaced with positive, forced ejection of material by hydraulic or mechanical action. Bowl and cutting-edge design which allows for maximum load with minimum effort has also increased production. An example of this was the introduction some years ago of the low-silhouette scraper bowl which reduced the work required to lift the material.

Jan 5, 1969

By Charles E. Locke

The little stamp-mill in the mining laboratory of the Massachusetts Institute of Technology and the work done by it have been well described by Prof. R. H. Richards and E. E. Bugbee in a paper read at the Albany meeting of the American Institute of Mining Engineers, February, 1903.' As run for student class-work the mill contains a feeder, stamps, plate, and vanner. Results in the past indicate that the work of these machines is just as efficient as that of a regular mill handling the same class of ore. It has been the custom to obtain ore principally from Nova Scotia, mainly because it is the nearest source of supply, and also because there is a considerable saving in freight-cost as compared with other districts. The gold in Nova Scotia ores is notoriously coarse, and for this reason it is almost impossible to obtain satisfactory results by sampling and fire-assay, unless an extremely large lot of ore is crushed and all of the contained gold pellets are saved. A very interesting and most extraordinary example of this fact has been presented by a recent run in the Technology stamp-mill. Since the capacity of the mill is about 60 kg. per hr., and since in about 5-hr. run the students in any one section have an opportunity to make the necessary study of machines, it usually happens that several runs are made from one lot of ore. When the shipment is received it is first dried and weighed, put through the Blake breaker, set at 1 or 1.5 in., and the crushed product is piled in a cone on the sampling-floor. When the crushing is completed the ore is usually stored away in barrels for future use; it is aimed to have each barrel of

Jan 1, 1914

By Orrin P. Peterson

The decision of the Supreme Court -of the United States not to review the findings of the lower courts closes an interesting chapter in the mining litigation that has arisen as a result of the extralateral feature of the mining law. The time seems opportune to record some of the important geological features, and also some of the legal features, of the controversy, in the hope that these will be permanently accessible to members of the mining profession. After many rumors of litigation, the Utah Consolidated Mining Co. sued its neighbor for the ore that had been, it was alleged, wrongfully extracted from its so-called Yampa limestone lode. This ore lay beneath Utah-Apex surface and was claimed by virtue of the extralatera1 rights conferred on the Utah Consolidated Co. through the ownership of certain specific mining claims, one of the principal claims being the Yampa. Previous to bringing suit, the Utah Consolidated Co. had strengthened its position by purchasing the Old Yampa mine and by making an agreement with the Utah Metal & Tunnel Co., which gave it clearer title to the outcrop of the Highland Boy limestone. Access to the workings of the Utah-Apex Co. was secured and reciprocal privileges gave Utah-Apex representatives the right to enter the properties of the Utah Consolidated Co. This resulted in the Utah-Apex immediately bringing countersuit for ore alleged to have been wrongfully extracted from under its surface in the Leadville country, see Fig. 4. Six cases came up for consideration: five related to the original suit and the countersuit, and one related to the Dana extralateral claims of the Utah-Apex Co. Well-known attorneys, geologists, and mining engineers were engaged by both sides, and thousands of feet of development work were done to prove or disprove ideas that would sustain the contentions of the opposing sides. Models of wood, wire, and glass were constructed to present clearly to the court the actual physical relations. These models were also of great value to the attorneys and witnesses in clarifying hazy impres-

Jan 1, 1924

By Thomas Fraser, H. F. Yancey

The jig may be termed the standard coal-washing machine. Although exact figures on the relative tonnages of coal treated by the various coal-cleaning processes are not available, it is known that a large part of all the coal given special cleaning treatment is handled by jigs. This wide use of the jig warrants a special study of its performance. In this paper are presented the results of an analysis of work done by a three-compartment jig in treating bituminous coal from the Thick Freeport bed in Allegheny County, Pa. Certain systems of washing coal require sizing before washing, while others treat unsized coal. The prevailing practice, however, for the preparation of coking coal from the more easily washed coal is to treat an unsized or natural feed of about — 1 in. size and smaller. Under such conditions, the minimum size of particle that is beneficiated has long been and is still a matter of discussion and conjecture. In a careful laboratory investigation J?ngstl concluded that the practical limit of settling of fine coal is reached at from 0.02 to 0.008 in. On the other hand, Hancock2 has found that single-compartment jigs, used in preparing coal for the domestic market, usually allow most of the heavy (refuse) particles smaller than 1/4 in. to go into the washed coal. He also states that it is impossible with the ordinary coal jig to make any noticeable improvement in the quality of the coal finer than 20 mesh (about 1/30 in.). Because of its importance in coal cleaning, the work described in this paper was undertaken for the purpose of obtaining information on this subject, as a part of the general coal beneficiation program being carried out by the Bureau of Mines.

Jan 1, 1925

By Courtenay de Kalb

The Exposed Treasure gold-mine has, for the past four years, been one of the largest producing mines of Southern California, its annual output havirig con~tituted I per cent. of the total gold and silver production of the entire State. At the present moment the property is idle, owing to the large quantity of water encountered on the lower levels, which will require the installation of a powerful pumping-plant before operations call be recommenced. Moreover, a prompt change in the character of the ore has occurred at water-level, which makes imperative an extensive campaign of development in the region of the un-oxidized ores before a plant adapted to their treatment call be definitely decided upon. The character of the changes encountered in these deeper ores makes the geology of this deposit a matter of importance, riot only for the immediate district, but for the desert region of Southern California in general, where many mines exist having in the oxidized belt conditions that, in many respects, resemble those in the Exposed Treasure mine. The deposit is situated in an apparently isolated butte about 2.5 miles south from the town of Mojave, on the Mojave desert. The butte, though apparently isolated, is in Fact geologicallg part of an extinct volcano, known as Soledad butte, which rises out of the plain 1.5 miles SW. of' the mine, to an altitude of 4,650 ft. above sea-level. Other buttes also rise from the desert plain toward the south and east, and again to the westward, all being closely related geologically to Soledad butte,—the whole constituting a single system as to origin and time. Since the end of the period of active volcanism in this region, there has been extensive denudation, the ancient plateau having been dissected during an epoch of apparently exces-

Jan 1, 1908

By C. C. Harris

This article presents a general equation describing the xYt surface in batch grinding. This equation contains as special cases most of the relationships which have been deduced from kinetic studies. In an earlier paper an analytical solution of the integro-differential equation of batch grinding was proposed1 as a first approximation of the xYt surface.' A more general equation will be presented here, which appears to combine in a single statement many conclusions reached by experiment. A possible underlying mechanism is that the changing product fineness leads to changes in the particle crushing strength and in the probability of encounter with the crushing media.

Jan 1, 1969

By Herbert E. Field

The study of the condition and action of carbon in iron and steel is singularly complicated, because one has to consider, also, many contemporaileous reactions foreign to the one under investigation. Great difficulty is experienced in studying iron in the melted state, or during its various treatments in a solid condition, hence such an inquiry must be confined chiefly to a study of the original substance, of the conditions surrounding its treatment, and of the finished product. From a knowledge of these three things, we must form our own conclusions as to what takes place during the transition-period. Inasmuch as it is impossible to determine quantitatively the changes which take place in iron during the various processes of treatment and alteration, we are forced at once into the field of theory for an explanation of many of the phenomena for which we have to account. A recapitulation of the recognized properties of iron and carbon, and of the conditions in which they exist in iron and steel, may be useful as an introduction to the discussion of the subject. Chemically pure iron is soft, malleable and easily welded. It carmot be hardened or tempered, as these terms are understood in relat.ion to steel. In contact with a magnet, it becomes magnetic, but loses this property when the magnet is removed. It is unfitted for castings on account of its lack of fluidity. Those properties of iron which render it valuable as a commercial product must, therefore, be primarily due to foreign substances contained in the iron; and the great variety of these properties is attained by changes in the amount and nature of these impurities, and by the physical treatment of the iron while it contains them. The following properties of carbon make it a prominent factor

Jan 1, 1904

By Gordon S. Duncan

The U. S. Geological Survey, I believe, has almost completed a study of the Harney Peak quadrangle, preliminary to the publication of a report on that district. As I was engaged for some months on an investigation of the mode of occurrence of the ore-bearing formation in this area, it has seemed to me timely to make public the results of my study, as a contribution to the consideration of this subject. It seems scarcely necessary to describe the locality and general geology of the Black hills of South Dakota, for since 1846 many have contributed information concerning this region, some of the reports bearing such well-known names as those of Walter P. Jenney, Henry Newton, S. F. Emmons, and C. R. Van Hise, while me have only to glance at Bulletin No. 4 of the South Dakota School of Mines, in which Prof. C. C. O'Harra, of that institution, has given us a bibliography of contributions to the geography and geology of the section, to find that other well-known men have studied the district, and have given us the benefit of their researches. The U. S. Geological Survey has made geological maps of nearly the whole of the Black hills, the only quadrangle yet to be conlpleted being, as stated, the Harney Peak district. During the late summer and autumn of 1910, it was my lot to examine and report on a considerable area in this neighborhood, which once had been prospected, and in some cases exploited, for tin. This paper gives an account of certain geological phenomena, noted at that time, which greatly influenced my conclusions. The predominating formation of the district is pre-Cambrian, represented by a highly-cleaved mica-schist, usually very gar-netiferous, and sometimes hornblendic. Rising like an island from the surrounding schist is a large mass of granite, known as

Jan 1, 1913