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By Edward Sayre

IN shaft sinking for coal mines, the cost item greatly influences the method adopted. This holds true especially when soft material must be traversed. The average life of a coal mine is short. This is clue either to the limited area of the coal basin or to the great expense of maintenance and haulage underground when the entries are extended a considerable distance from the hoisting shaft. Therefore, the engineer in opening a coal mine is confronted with the fact that the cost must be kept within certain bounds else the venture will prove unprofitable. For this reason he may be prohibited from adopting certain safe, but expensive, methods that are used in sinking caissons for foundations, driving transportation tunnels, or other work of permanent construction. A common method of sinking through difficult ground employs the aid of a steel shoe pushed ahead of the shaft timbers. Another is the drop-shaft method. These two methods were used in sinking the main shaft and the air shaft of the Eagle No. 3 mine, at Des Moines, Ia., and the following data show the relative success and cost of the two methods of sinking under the same conditions. A drill log of the material to be penetrated was as follows (see Plate 1, Fig. .1)

Jan 9, 1916

By W. L. Austin

THE advance made in recent times in this branch of metallurgy is indicated y the attention the subject is receiving from important American copper-producing companies. Reference to the files of publications devoted to the mining industry discloses that some 20 American companies are actively investigating the amenability of their ore, or other material, to leaching methods, and that plants of varying capacities up, to 10,000 tons per day are under construction or are projected. Several leaching works are in commercial operation. It has been frequently pointed out that no method of leaching is universally applicable, for the reason that each ore differs in some particular from apparently similar ore found elsewhere, and also because local conditions are rarely the same even where the ore closely approximates in character that being worked at some other point. For this reason the older companies are approaching the matter in a conservative manner, experimentally determining for themselves the salient features in each instance. In considering a leaching proposition three factors at once fix the attention: (1) disengaging the metal from mineralized forms in Which it is found in nature; (2) recovering the metal in a commercial state after it has been dissolved; (3) the apparatus best adapted to carrying out the several operations.

Jan 8, 1914

By D. M. Jamieson, M. P. Pearse, E. R. A. Plumstead

In 1948 the shaft sinking record in the Republic of South Africa was held by the Van Dyk Consolidated Mines Ltd. for a ventilation shaft with a footage of 461 ft sunk during the month of August 1941. This record remained for some ten years; but in the ensuing nine years it was broken no less than 13 times. Table I gives shaft sinking records throughout the world for the 21 years, 1940 to 1960. History shows that the wide, deep, timbered rectangular shaft had passed its peak of popularity by 1948, although it still had a great deal to commend it, both from the sinking and operational points of view. In sinking, it is easy to clean manually, and water can be handled by bailing when wet ground has to be negotiated; its shape also lends itself to equipping concurrently with sinking. In operation it provides the most convenient "in line" hoisting arrangement, and if the ventilation requirements so demand, it offers the simplest solution in that it can be divided into upcast and downcast sections. Furthermore, in the case of a multi-level mine, the shaft compartments can be reduced conveniently if the full area of the shaft is not required to serve all levels.

Jan 4, 1963

By J. B. Clemmer

PRODUCTION of magnesium metal in the United States during the past decade has increased from less than 600,000 lb. in 1928 to more than 4,800,000 lb. in 1938.1 The growing industry has stimulated interest in methods of production and in sources of raw material. All of the present domestic production is from brines. However, the availability of large tonnages of magnesite in the state of Washington, together with the possibility of cheap power, have created interest in the utilization of magnesite for the production of magnesium metal as well as for other purposes. Magnesite, the carbonate of magnesium (MgC03), usually is associated with lime-stone (CaCO3) and dolomite (MgC03 CaCO3). It occurs in crystalline and microcrystalline (sometimes termed amor-phous) forms.2 The more common crystal-line mineral is found in various shades of white, gray, yellow and brown, the colors being due to impurities, chiefly iron. Magnesite has a hardness of 3.5 to 4.5 and a specific gravity of 3.0 to 3.1. It forms rhombohedral crystals in the hexagonal system, having a vitreous, pearly luster. The quarries and mines of the Northwest Magnesite Co. near Chewelah, Wash., are large producers of magnesite for refractories.

Jan 1, 1940

By A. Donald Kelmers, Forest G. Seeley, B. Zane Egan

INTRODUCTION Coal ash, presently the fifth most abundant of the solid minerals produced in the United States, is expected to become the fourth most abundant by the end of this decade (1). The production of fly ash from the combustion of pulverized coal amounted to a total of 44 million metric tons (Mt) in 1977 and is expected to Increase to 91 Mt by 1985. Coal ash, which results from the Inorganic clay and mineral content of the coal, contains several elements and thus can be considered as a mined and crushed mineral resource rather than a waste material Furthermore, potential problems associated with fly-ash disposal ponds and the leaching of potentially hazardous elements through groundwater infiltration and/or rainfall provide additional incentive for processing fly ash for environ- mental control as well as for the recovery of certain metal values. Fly ash could provide an abundant domestic source of aluminum and several other metals Aluminum is now recovered from bauxite, and over 90% of this ore is imported since domestic sources are limited and cannot meet the U.S. demand There is a close relationship between the aluminum content of fly ash and the domestic consumption of this metal (Table 1).

Jan 1, 1981

By H. Hanemann

THE application of other than mechanical methods to the study of the mechanical-physical properties of metals has become in the last few years a topic of investigation of ever-increasing interest, both from the theoretical standpoint and from that of the engineer and constructor. Besides the investigations which have been made of 'the magnetic properties of ferromagnetic metals, in their relation to the mechanical properties of these metals, which will be discussed more in detail below, there have been made studies of other phenomena in the same relation, and methods for the mechanical testing of metals have even been suggested, for example, the microscopic method of Tammann,1 and the thereto-electric, method of Turner2 for determining elastic limits. The application of all such methods, which are based upon the dependence of some physical, crystallographic, or possibly chemical property, upon the mechanical state of the metal, must be preceded by close and careful correlation of these various "test" properties with the known mechanical state of the different metals or materials. It is with this view that the present work, as well as that of many previous investigators of, what .may be termed in the interests of brevity, the mechanical-magnetic properties of ferromagnetic materials of construction, has been done.

Jan 12, 1915

By J. F. Sepulveda, J. D. Miller

Tar sand deposits in the state of Utah contain more than 25 billion bbl of in-place bitumen. Although 30 times smaller than the well-known Athabasca tar sands, Utah tar sands do represent a significant domestic energy resource comparable to the national crude oil reserves (31.3 billion bbl). Based upon a detailed analysis of the physical and chemical properties of both the bitumen and the sand, a hot-water separation process for Utah tar sands is currently being developed in our laboratories at the University of Utah. This process involves intense agitation of the tar sand in a hot caustic solution and subsequent separation of the bitumen by a modified froth flotation technique. Experimental results with an Asphalt Ridge, Utah, tar sand sample indicated that percent solids and caustic concentration were the two most important variables controlling the performance of the digestion stage. These variables were identified by means of an experimental factorial design, in which coefficients of separation greater than 0.90 were realized. Although preliminary in nature, the experimental evidence gathered in this investigation seems to indicate that a hot-water separation process for Utah tar sands would allow for the efficient utilization of this important energy resource.

Jan 9, 1978

By J. Charles Miller

THE expansion of facilities for rapid transportation of perishables by train, truck and airplane has necessitated consideration of refrigerants of a minimum weight and volume per pound of cooling and has stimulated the use of solid carbon dioxide commercially. The gas probably has not had wide application in the past in air-cooling equipment for mines, theaters or buildings, owing to its thermodynamic properties, as will be deduced from examination of Table 2. However, consumption of the liquid in carbonating beverages remains a dominant factor. In addition to these uses, carbon dioxide is employed to a limited degree as an explo-sive in the liquid form, as a freezing agent in plumbing, in laboratories for low-temperature work, and in the manufacture of golf balls. SOURCES The principal sources of the gas at present are coke ovens, lime kilns, breweries and other fermentation plants, all of which are within easy reach of markets. Natural sources, however, have not received the consideration they merit, mainly because of their isolation. It is asserted by some manufacturers that the carbon dioxide gas produced from wells is unsatisfactory because it often contains impurities that are difficult to remove, while that produced as a byproduct is much purer or contains impurities that are easier to remove.

Jan 1, 1936

By L. J. Gurevich

IN the course of the examination, at the Bureau of Standards, of fusible tin boiler plugs for the Steamboat Inspection Service, it became evident that an investigation should be undertaken to determine the precautions necessary in the manufacture of acceptable plugs. The results of the tests of these plugs show that their manufacture has improved, though at present not all of the plugs tested are satisfactory. Table 1 gives the result of tests of some 1500 plugs from about 100 makers. Records of the tests show that several of the makers were able to produce satisfactory plugs with every pouring. The Steamboat Inspection Service has the following specifications for fusible plugs: "Fusible plugs for use in boilers of steam vessels under the Jurisdiction of the Steamboat Inspection Service shall be made of bronze casing with the bore tapering continuously and openly from end to end, and filled from end to end with tin not less than 99.7 per cent. pure and to contain not more than 0.1 per cent. of lead and not more than 0.1 per cent. of zinc. The small end of the bore may be countersunk not more than 1/32 in. in depth and width, but no recess, thread, or cavity other than this countersink shall be allowed."

Jan 8, 1919

By George J. Young

Discussion of the paper of George J. Young, presented at the San Francisco meeting, October, 1911, and published in Bulletin No. 59, November, 1911, pp. 839 to 872. ASKIN M. NlCHOLAS, Melbourne, Australia (communication to the Secretary) : * Professor Young deals with quite a variety of machines and methods, but, strangely enough, makes no mention of the work done by me, although he concludes with the remark that the " thin-cake continuous filters are a decided improvement over the thick-cake filters." As those interested in slime-treatment may consider that I did nothing more than to patent a process, I submit Fig. 1, showing the working-drawings of a machine, made, tested, and proved to work satisfactorily by me early in 1905. This time is prior to any work done in slime-filtration with rotating filters by E. L. Oliver or others. I maintain that a number of appliances now in use for slime-filtration infringe my patents. And after most exhaustive inquiry, I know of no machine or process, prior to my description in 1899,1 that embodied getting rid of the residues by holding them on the cloth with the vacuum, and then discharging them with back-pressure, so as to form a cycle of the operation, the result being continuous treatment. I therefore think that any paper dealing exhaustively with this subject is not complete without a reference to the work that I have done. * Received Mar. 11, 1912. 1 U. S. Patent No. 619,211, Feb. 7, 1899.

Aug 1, 1912

By E. H. Dix

The purpose of this paper is to introduce the subject of Stress-Corrosion Cracking at the Joint Symposium of the American Society for Testing Materials and the American Institute of Mining and Metallurgical Engineers. In this Symposium we are concerned with spontaneous cracking which results from the combined effect of high, prolonged stress, and corrosive attack. Stress-corrosion cracking may be considered a specific phase of the more general subject of the effect of high constant stresses in accelerating the rate of corrosion of metal products. The kindred subject of corrosion fatigue in which the life of a metal part under repeated stresses is reduced by corrosive attack is not a part of this Symposium. Likewise "creep," the failure of a metal part by high constantly applied stress, in the absence of a corrosive environment, is not to be included. How- ever, corrosive influences may have more effect on creep failures than is sometimes realized. The penetration by molten metals such as often occurs during tinning or soldering operations, or by mercury, frequently causes cracking when the part is stressed. Strictly speaking this is not stress-corrosion cracking. However, the committee has decided that this phenomenon should be included in the Symposium. The penetration by molten metals such as often occurs during tinning or soldering operations, or by mercury, frequently causes cracking when the part is stressed. Strictly speaking this is not stress-corrosion cracking. However, the committee has decided that this phenomenon should be included in the Symposium.

Jan 1, 1945

By C. O. Babcock

In this Bureau of Mines report, the authors present the results of laboratory tests on the burst proneness of coal. Many researchers have studied the violent breaking of large coal masses in underground mines, called bursts, but the causes remain uncertain. They have often assigned to geology and gas pressure the causative roles. The objective of this work is to show that stress can produce bursts in many coals if constraint is necessary for pillar survival and is suddenly lost. We tested coal samples from 15 mines, in 11 coal seams, in six states in the laboratory, and 13 were made to burst. These bursts were produced in several ways, but segmented steel platens were used in the tests reported. Two parameters analogous to the momentum and kinetic energy were used to rank the burst proneness of the coals tested. Tangential strains over the lower surface of the model coal pillar were measured to reveal a periodic slipping prior to the burst. High-speed motion pictures (350 frames per second) reveal the burst behavior in slow motion. We propose a modified Mohr-Coulomb stress-failure criterion to describe the burst behavior. When the horizontal constraint is suddenly lost with little change in the vertical stress, the Mohr stress circle increases in size dynamically, exceeding the static failure condition. When the inertia of the coal mass is overcome, a burst occurs. We conclude that most coals can be made to burst and that such bursts can be expected in mining at increasing depths.

Jan 1, 1984

IT will be recalled that the first professor of metallurgy in the United States, appointed in 1855, never really gave any instruction in metallurgy and gradually turned into a professor of mineralogy. Metallurgy was included with mining in the early curricula, two students who took the B.S. in mining engineering from the Polytechnic College of Pennsylvania in 1863 wrote their graduation theses on the metallurgy of copper and zinc, respectively. Even after Columbia School of Mines established, in 1868, a separate curriculum leading to the Ph.B. degree in metallurgy, very few students elected it,* preferring to take the mining degree, since they received in its curriculum nearly all the metallurgical instruction they would have in the metallurgical curriculum. For many years a large proportion of the men who attained prominence in metallurgical enterprises had taken mining rather than metallurgical degrees. METALLURGY Clifton Sorby's study of thin sections of rocks under the micro- scope, beginning in 1850, and its subsequent development by Zirkel and others, had made microscopic petrography a recognized department of, geological research as early as 1873. It was inevitable that the idea of studying polished metal surfaces under the microscope by reflected instead of transmitted light would occur to investigators. Sorby himself did it in 1864, and Adolph Martens and Floris Osmond may be especially named ', among the many European workers who, by the late eighties, had so developed the necessary techniques that they were able to photograph polished metal surfaces at magnifications as high

Jan 1, 1941

By Wayne A. McCurdy

Seldom in history has any industry undergone such radical and rapid change as that experienced by coal. Since 1947, when bituminous coal production reached an all-time high of 631 million tons, the industry has faced market problems not believed possible prior to the build-up of the great market demand occasioned by the wartime emergency and post-war recovery period. Subsequently, it suffered practically complete loss of the formerly huge railroad fuel market to dieselization; natural gas expansion ate into many markets; and oil took a heavy toll. Although anthracite, on the other hand, did not have a record year in 1947, it did attain a production figure of 57 million tons. Competitive forces since then have hit this fuel harder than bituminous coal. As we are aware, most prognosticators have pointed to a glowing long-range future for coal, with some forecasters estimating coal production by 1975 to be as high as 800 million tons. The largest increase in the use of coal in future years is expected to come from expansion of the industry's two largest growth markets-steel and the electric utilities. Optimists would have us believe that coal need merely bide its time to be carried to prosperity by the increased demands of these two basic customers. But the coal industry knows from bitter experience that even "assured" markets-as the railroads and domestic consumers once were-can be lost through lack of progress and lack of research. And coal's projected growth markets are not “assured.”

Jan 9, 1962

By Svend Rordam

THE development of a cement that will resist the destructive action of sea water and other corrosive waters is a problem that has occupied cement chemists for the past one hundred years. It has been found that of the various salts that commonly occur in corrosive waters, sodium sulphate, magnesium sulphate and magnesium chloride are most destruc-tive to cement. Many investigations have been carried out in the United States, in Canada, and in Europe to solve the problem of what constitutes a sulphate-resistant cement, and during the past 10 years some of the findings give definite information in this respect. COMPOSITION OF CEMENT Portland cement is composed of four major compounds: 1. Tricalcium silicate 3CaO.Si02 (C3S) 2. Dicalcium silicate 2CaO.Si02 (C2S) 3. Tricalcium aluminate 3CaO.Al203 (C3A) 4. Tetracalcium aluminoferrite 4CaO.Al203.Fe203 (C4AF) The two calcium silicates are the main contributors of strength. The tricalcium aluminate contributes some to the early strength of the cement but has the least resistance of the four compounds toward the attack of sulphate waters. The tetracalcium aluminoferrite does not contribute very much to the strength, but is far more resistant to sulphate waters than the tricalcium aluminate. When hardened cement is exposed to water containing sodium or magnesium sulphates, these salts will react with the hydrated tricalcium aluminate in the cement and form compounds that will cause a swelling, disruption and crumbling of the hardened cement.

Jan 1, 1939

By F. Julius Fohs

A comparative balance sheet for 1924 and 1925 follows: 1925 1924 Barrels Barrels Gross production..................................... 763,000,000 714,000,000 Imports of crude oil.................................. 62,005,000 77,776,000 Imports of refined oil................................. 16,263,000 16,470,000 Total......................................... 841,268,000 808,246,000 Surplus supply....................................... 25,000,000 30,246,000 Indicated domestic demand........................... 704,465,000 667,000,000 Exports crude oil.................................... 13,353,000 17,913,000 Exports of refined oil................................. 98,450,000 93,087,000 Total......................................... 816,268,000 778,000,000 Stocks, Dec. 31 (crude 410,654,000).................... 538,000,000 513,000,000 These figures show an increase of 49,000,000 bbl. in production and little change in oil imported; 37,000,000 bbl. greater apparent domestic consumption and actually greater utility in consumption, due to increased gasoline production by cracking; and 1,000,000 bbl. more crude and refined oil exported in 1925 than 1924, representing a total apparent increased demand of 38,000,000 bbl. The excess of demand over supply in 1925 was 25,000,000 bbl. The increase of stocks over those at the close of 1924 was 25,000,000 bbl. Of the stocks on hand at the close of 1925, about 82,000,000 bbl. in California were not refinable. Imports from Mexico and South America It would not be surprising if, by 1930, we should actually welcome the imports from Mexico, Venezuela, Colombia, Peru, Argentina and Trinidad. If these States produce 155,000,000 bbl. and use, perhaps, 30,000,-

Jan 1, 1927

By Colin MacDonald

The choices of an uranium mill flowsheet are pri- marily determined by economic feasibility with plant location and regulatory bodies playing a lesser but still important role in this determination. The host ore bodies will determine the leach pro- cess to be used for basic uranium extraction. Im- mediately following this decision, the method of leaching has to be determined. These can be: - Atmospheric leaching - Pressure leaching - In-situ leaching - Heap leaching The three previously stated criteria lay important parts in this decision. In the case of atmospheric or pressure leach and once the soluabilized uranium has been liberated from the host gang material, liquid solids separation becomes the major criteria. Three process flowsheets are available; they being: -Countercurrent decantation - Countercurrent or co-current filtration - Resin in pulp Following liquid solids separation, concentration and precipitation become the next variable choice. They being: -Solvent extraction - Fixed bed ion exchange - Fluid bed ion exchange Lastly, washing and drying of the precipitated product to remove impurities can be carried out by either filtration or centrifugation. With the exclusion of milling circuits, grinding circuits, flotation circuits, and calcining processes, we have 240 variations of the flowsheet between leaching and a dry washed precipitate. Of this total, filtration in one form or another and in single or multiple applied forms has application in 144 streams. This paper intends to discuss four (4) facets of the total flowsheet in which filtration is applied, following grinding and prior to calcining. They are: - Leached pulp liquid solid separation - Tailings dewatering - Pregnant solution clarification - Yellow cake washing and dewatering

Jan 1, 1980

By William Glenn

Early in the last century, Isaac Tyson, Jr., of Baltimore, was a miner of ores of chromium, iron and copper, and a manufacturer of their products. He was first to erect in America, for the reduction of copper-ore, a German blast-furnace, which was copied largely, and the improved successors of which are now universally used in this country. Dying in 1862, he left his manufacture of alkali bichromates to his eldest son, Jesse, while his work in the departments of mining and smelting descended to his second son, James Wood Tyson, the subject of this notice. The father had mined chrome-ores in Maryland and Pennsylvania and manufactured their products at Baltimore; he had mined and reduced copper-ores in both these States; iron-ores at Tyson Furnace in SW. Vermont, and copper-ores in the northern and central parts of that State. Among his holdings was what later became the Ely mine, now called Copperfield. The son extended this work to central Georgia, and carried the family mining interests to the Pacific coast, where he took up chrome-mines in Oregon and elsewhere, as far south as southern California. On December 3, 1900, in the 73d year of his age, James Wood Tyson passed away, in his native city of Baltimore, charging his third son, James Wood Tysou, Jr., with the labors which, 38 years before, his father had resigned to him. Thus was the work of father and son in mining and metallurgy, continuing without interruption through almost

Jan 1, 1902

C. A. Stetefeldt, San Francisco, Cal. (communication to the Secretary): In view of Mr. Louis's statement that the balance and weights employed in his experiment were '(by no means first-rate," the results can scarcely be entitled to weight. And if a slight variation in specific gravity were to be accepted as proof of the existence of allotropic modifications, we should be obliged to conclude that every metal existed in such modifications. When the observed specific gravity of an alloy (as is often, and perhaps generally, the rase) differs from the calculated one, it seems more reasonable to explain the difference (apart from errors of determination) by assuming that actual chemical combination takes place between some atoms of the metals. MR. Louis (communication to the Secretary): In reply to the criticisms with which Mr. Stetefeldt has favored me, I beg to point out to him that, in the first place, I do not myself attach very much weight to the results I have obtained. I merely claim to have pointed out that amorphous gold obtained from dissolving up the alloy with silver has a higher specific gravity than common gold—a result corroborated by the quoted results of Rose. At any rate, it is easy to repeat my observations, and I hope this may be done by men who have better opportunities than myself for this investigation. Surely it is worthy of attention from assayers at the mints. I am not prepared to say that I should regard slight variations in specific gravity as absolute proof of allotropism, but I do consider

Jan 1, 1894

By D. W. Fuerstenau

THE object of this article is to point out the experimental relationship which exists among contact angle, adsorption density, zeta potential, and flotation rate data. In each of the experiments discussed in this article, the surface properties of quartz, as a function of pH, were measured in solutions to which constant quantities of dodecylam-monium acetate were added. Morrow1 and deBruyn2 worked with solutions containing 4.08x10-5 moles per liter, whereas Fuerstenau3 and Seele worked with solutions containing exactly 4x105 moles per liter, but this difference is not significant. The pH of the solutions was regulated with HCI or NaOH in all cases. In each case, the addition of collector was constant, but the concentration of dodecylammonium ions decreased because of the formation of dodecylamine at higher pH values.2 Contact Angles: Gaudin and Morrow1 presented data for the contact angle of quartz in solutions containing 4.08x10-5 moles of dodecylammonium acetate per liter between pH 2 and pH 10.15. Using the same captive bubble techniques, the writer measured contact angles on quartz in solutions containing 4x105 moles of dodecylammonium acetate per liter at pH values ranging from 9.9 to 13.2. Both sets of data are presented in Fig. 1, in which the contact angle in degrees is plotted as a function of the pH of the solution. From pH 2 to about 8, the contact angle

Jan 1, 1958