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By W. J. PRIESTLEY

WHEN during the war the Navy Department decided to build an armor-plate and gun-forging plant of its own at South Charleston, W. Va., one of the most important units of the equipment proposed was a 14,000 gross ton forging-press to be used for forging, bending, and rectifying battleship armor-plate and making hol¬low forgings for large caliber guns. A press suitable for doing this kind of work was put into operation in the fall of 1921 and was operated successfully on armor-plate and large forgings until the closing down of the ordnance plant following the Limitation of Armament Conference held in Washington, February, 1922. PURPOSE OF THE PRESS There are three methods by which armor-plate can be made, namely, hammering, forging, and rolling the ingot. Each method produces a different result in the mechanical working of the steel. The hammer was eliminated as impractical from an operating standpoint. The first armor-plate made in this country was worked under a hammer at the Bethlehem Steel Co., between the years 1891 and 1893, but was superseded by forging when the large press was completed in 1893. Harry T. Morris of the Bethlehem Steel Co. informs me that the 1.25-ton steam hammer began operations in 1891 and was in operation for about two years. The Carnegie Steel Co. and the Midvale Steel and Ordnance Steel Co. also forged armor-plate. Certain European manufacturers rolled the plates from large slab ingots, after removing the sink-head and giving the body of the ingot a light pass under a hydraulic press. While rolling accomplished more mechanical work on the surface of an armor plate, forging, on the other hand, resulted in a greater amount of work in the interior of the plate. Either type of equipment involved an enormous expendi¬ture, so it was deemed advisable to adopt the method which would make it possible to use the equipment for more than one purpose. Since g large rolling-mill could be used only for the single operation of rolling armor-plate, a press was decided on, for the reason that it might be designed so as to forge armor, as well as bend and rectify it, and also be used in the forging of ingots for large caliber guns, both in the form of hollow forgings and also solid shafts.

Jan 1, 1926

By Forrest K. Pence

BENTONITE deposits are known to occur in Texas within the Jackson group of formations. This group represents the uppermost Eocene age sediments found in the coastal plain area of Texas. It outcrops across this area of the state in a narrow band of some 4 to 20 miles width. The outcrop pattern roughly parallels the present Gulf of Mexico shore line and is some 100 miles inland from the Texas shore, Fig 1. The principal bentonite deposits are found in the areas where this outcrop pattern cuts across the south-central Texas counties of Karnes, Gonzales, and Fayette. In these deposits, the better quality bentonite is found in the lower or bottom layers of the volcanic ash deposits in which they occur. Some of these better quality bentonites develop very light colors upon firing and therefore justify their being classified as "white firing." The deposits in Karnes and Gonzales Counties apparently occur in commercial quantity, whereas the white firing strata so far uncovered in Fayette County have been too thin to be classified as yet as "commercial." A study of the ceramic properties of the weathered ash in Gonzales and Karnes Counties was reported in 1941.1

Jan 1, 1949

By Strathmore R. B. Cooke

On the basis of experiments con- ducted on quartz using a bubble pick-up method, it was shown in an earlier paper1 that this mineral will preferentially adsorb hydrogen, calcium, or sodium ions, depending on the relative concentrations of those ions in the solution in which the quartz is immersed. For quartz particles ranging in size from 0.2 to 1 mm, it was demonstrated that the concentration of calcium in solution (assumed present as ions) necessary to completely activate quartz for flotation is given by the expression: In this expression, ionic concentrations are in mols per liter. It was further shown that the pick-up method is apparently more sensitive to changes in reagent concentration than the standard captive-bubble method, and that induction times are apparently much reduced. Since completing these earlier tests, a new type of cell has been constructed; this is shown in Fig 1 and 2. In Fig 1, A is a ground joint, B is a ceutral tube reaching to within a few millimeters of the bottom of the cell, and C is a stopper which may be removed for re- agent addition, and serves the further purpose of excluding carbon dioxide from the air during the test. The entire cell is constructed of Pyrex glass, and does not give the trouble experienced with the earlier cell, in which activating ions were released from the glass at high pH values. The only critical factor in the construction of the cell is the clearance between the central tube and

Jan 1, 1949

By Jay F. Smith

The Alan Wood BOF Shop consists of two 140 ton furnaces with a rated yearly capacity of 1-1/4 million ingot tons, he hot metal for the BOF Shop is supplied by two 18 foot blast furnaces which produce an average of 2000 tons per day, To achieve the rated ingot ton capacity with this limited supply of hot metal, the preheating of scrap is necessary. This is accomplished in the furnace by using an oxygen-natural gas burner. Piping Arrangement The natural gas and oxygen are piped into the Shop through 8-inch lines to their respective valving stations. As can be seen from Figure 1, the flow of natural gas passes through a flow control valve which is common to both furnaces, after which it divides into two 6-inch lines forming two identical and independent gas control lines, one for each furnace.

Jan 1, 1972

In the January Bulletin a list was published of Societies' publications, magazines, etc., which were duplicates and were discarded at the time of-the consolidation of the libraries of the three Founder Societies. A second list published herewith includes text books which are duplicates and which will be disposed of about April 1, 1916, by the Board of Directors of the Institute through the, Library Committee.. If, meanwhile, members desire to secure some of these books, they are asked to communicate at once with the Secretary as. this is an unusual opportunity to secure books at an extremely low price. Airy, George Biddell.-Magnetism, London, 1870, Bd. Alberti, Friedrich von.-Halurgische geologic. Erster Band. Zweiter Band. Stuttgart, 1852, Bd. American Iron and Steel Association.-Ann. Rep. of the Sec'y. Statistics of American and, Foreign Iron Trades, 1877. Phila., 1877, Bd. Same, for year 1878. Phila., 1879, Bd. American. Telephone and Telegraph Co.-Ann. Rep. of Directors to Stockholders, 1911. N. Y., 1912, paper. Armagnat, H.-Induction Coils. Trans. by Otis Allen Kenyon, N. Y., 1908, Bd. Armstrong Cork Co. Insulation Dept. Nonpareil Corkboard Insulation. Pittsburgh, 1909, Bd. Associazione fra gli Industriali Metallurgici Italian.-The Metallurgic industry of Italy. Description of some of the principal works. Milan, 1911, Bd.

Jan 2, 1916

By K. A. Pauly

(Wilkes-Barre Meeting, June, 1911.) COMPRESSED air has been and is still very extensively used in connection with mining-operations, but its application in the past has been almost entirely confined to supplying power to underground machinery. Its introduction was due to the difficulty of taking care of the steam which is exhausted underground, rather than to any advantage in efficiency to be gained by its use. The ease with which electric power may be carried to the remotest parts of the mine and the high efficiency of the electric motor have long been appreciated by mine-operators, and electric power is now extensively used underground in the more recent developments, while many of the compressed-air engines in the older workings are being rapidly replaced by electric motors. Recently, however, it has been suggested to use compressed air for driving the large shaft-hoists, the air for the engines being supplied by electrically-driven compressors, and an installation of this character is being erected at Butte; Mont. It is the object of this paper to compare the compressed-air system of hoisting with the various electrical systems, from the stand-points of first-cost and cost of operation. However, before entering into a discussion of the various systems, it will be well to consider briefly the conditions affecting the choice of a system of hoisting in which electricity is the ultimate source of power. The power required by a mine-hoist is extremely intermittent and fluctuates between very wide limits, the all-day average consumption of power not exceeding from 5 to 15 per cent. of the maximum demand during hoisting. The cost of supplying power for such a fluctuating load is necessarily higher than that for supplying an equal amount of

Dec 1, 1911

By Christopher J. Bise

Introduction In August 1977, the federal Surface Mining Control and Reclamation Act was signed into law. It stated that: "The Congress finds and declares that because of the diversity in terrain . . . and other physical conditions in areas subject to mining operations, the primary governmental responsibility for developing. authorizing, issuing, and enforcing regulations for surface mining and reclamation operations subject to the Act should rest with the States." Section 516 of Title V (Control of the Environmental Impacts of Surface Coal Mining) of the Act deals with the surface effects of underground coal mining operations. "Each permit issued under any approved State or Federal program pursuant to this Act and relating to underground coal mining shall require the operator to adopt measures consistent with known technology in order to prevent subsidence. causing material damage, to the extent technologically and economically feasible, maximize mine stability, and maintain the value and reasonable foreseeable use of such surface lands, except in those instances where the mining technology used requires planned subsidence in a predictable and controlled manner: Provided, that nothing in this subsection shall be construed to prohibit the standard method of room and pillar mining." This section raises many questions. Precisely what is the "reasonably foreseeable" future as far as land use is concerned? And what is the "standard method of room and pillar mining"? The first part of the paragraph seems to rule out longwall mining, but isn't longwalling a "predictable" manner of "planned subsidence"? Does the Act take into account variations among mining methods in differing regions or coal seams? With these questions and the need to comply with the Act's provisions in mind, many states may turn to the Pennsylvania Bituminous Mine Subsidence Act of 1966- the only comprehensive subsidence act passed by any state-as a model for their own programs. Thus, it is very important to evaluate Pennsylvania's Act to see whether its basic assumptions can accommodate national application. This paper will note the Subsidence Act's provisions and guidelines, briefly analyze the current state-of-the-art in subsidence damage prevention and control, and list several recommendations for altering the Act's application guidelines for different mining areas.

Jan 1, 1982

By William G., Pariseau

There are important phenomena in rock and soil mechanics that cannot be explained in terms of theories of homogeneous, isotropic materials. Subsidence of strata about mine openings is an example. In-situ stress measurements in nonisotropic sedimentary, and metamorphic rocks is another. Patterns of joints, faults, fractures, and similar geologic features impart directional mechanical properties to rock masses that are locally isotropic or anisotropic. On the geologic scale, the non-homogeneity of composite rock masses may, in certain instances, be dealt with as homogeneous anisotropy. The mechanics of large rock masses can, therefore, be expected to involve considerations of anisotropy. The source of the anisotropy is not relevant. Once the scale of observation is selected and the material is defined accordingly, the analysis of stress and deformation proceeds without regard to the numerical values of the material constants. There are also important phenomena in rock and soil mechanics that cannot be explained in terms of linear elasticity, theory. For the mechanical description of anisotropic geologic materials capable of de- forming beyond the limit of purely elastic strains, a plasticity theory is required.

Jan 1, 1972

By A. Lubinski, C. R. Stewart, K. A. Blenkarn

Storage porosity has been considered one of the important pore geometry characteristics of heterogeneous-porosity limestones. Storage pores are only containers for fluids, in contrast to flow channel pores which both contain fluids and provide continuity for fluid flow. The concept of another geometry characteristic, "poro-striction", is presented as a second pertinent variable in describing limestone pore space. In simple terms, poro-striction is a measure of the flow resistance between storage and flow channel pores. Alternating-flow core-testing theory provides flow relationships which can be used to divide the pore space of heterogeneous-porosity media into flow channel and storage pores and to measure the "porostriction" of the latter. Experimental application of this theory to naturally occurring heterogeneous limestones shows that "porostriction" and the ratio of storage to flow channel pores can be estimated. Porostriction and porosity ratio are microscopic characteristics which should influence oil-recovery efficiencies during certain types of displacement processes. A knowledge of pore geometry should be valuable in designing or selecting the most effective oil-recovery process for heterogeneous limestones containing storage porosity. INTRODUCTION The primary and secondary recovery of oil from limestone (carbonate) reservoirs has been and will continue to be a major source of the world's supply of petroleum. Oil recovery from this type of formation is strongly influenced by the size, shape and arrangement of the pore spaces which hold the formation fluids. Therefore, it is expected that better knowledge of pore geometry would lead to design of more effective recovery processes. The concept of storage and flow channel pores has been presented as an important characteristic of limestone porosity.1 In this concept, storage pores are only containers for fluids, whereas flow channel pores are those pores which both contain and transmit the fluids. The work reported herein involves the concept of an additional pore characteristic called "porostriction". This characteristic can be visualized as the flow resistance between the storage and flow channel pores. This resistance is an important pore geometry characteristic because it determines how easily gas and oil can replenish fluids removed from the flow channel pores. Fatt and co-workers at the U. of California have studied the effect of storage porosity and a factor similar to porostriction on transient-flow response of models of porous media during a pressure build-up or drawdown test.55 These models consisted of porous sandstone cores with artificially simulated storage pores. It is the purpose of this paper to describe tests which permit the storage porosity and porostriction of actual reservoir core samples to be estimated. The tests used for this purpose involved not transient tests but, rather, an alternating-flow technique in which pressure and flow are varied according to a sine-wave relationship. This technique may offer advantages over transient methods. THE POROSTRICTION CONCEPT Before discussing alternating-flow (A.F.) tests in core samples, it is necessary to define the porostriction parameter. For this purpose attention is focused upon an elemental volume v representative of a porous medium having both flow channel pores and restricted-access storage pores. For such an elemental volume, it is considered that the storage porosity is combined to form a single pore and that the access into the storage porosity may be represented by a single capillary tube connecting the single pore to the flow channels of the elemental volume. Let the radius of the capillary tube be designated as Rc and its length as L,. When fluid flows into or out of the pore, the following equation (Poiseuille's law) relates flow rate q to pressure drop p, and the physical characteristics of the tube and the fluid of viscosity jx.

By Thomas A. Steven

Most mineralized areas in the central San Juan Mountains, Colorado, are associated with the youngest subsidence structures in a large volcanic cauldron complex that formed concurrently with eruption of the surrounding ash-flow field. Two local types have been recognized: (1) fissure-vein deposits along faults characterized by relatively late movement, and (2) hydrothermally altered and mineralized areas associated with postsubsidence Fisher Quartz Latite centers. The first type has provided most production in the past; the potential of the second type has yet to be adequately tested.

Jan 1, 1968

By T. Fraser, R. L. Sutherland

Under a cooperative agreement between United States Bureau of Mines and the Truax-Traer Coal Company, some operating-scale experiments have been made with the cyclone thickener in the preparation plant of the Shamrock No. 1 mine at Kayford, West Virginia. These tests were made with a 14-in. cyclone of the type developed by the Dutch State Mines in Limburg. It was applied experimentally to the thickening of solids in washery water to obtain performance data to show the range of sizes that may be recovered and other operating characteristics that would indicate the field of usefulness of this device in coal preparation practice. This is a progress report only. It covers results obtained in a series of 17 tests of the operation of what has been considered a unit of commercial size operating on suspensions of fine coal mixed with a relatively small amount of freeimpurities. The underflow material, after further dewatering in centrifuges, is a marketable grade of coal.

Jan 1, 1949

Jan 1, 1924

Jan 1, 1947

Jan 1, 1947

By N. D. Policow, J. S. Orphanos

Dewatering fine clean coal fractions, -595µm (-28 mesh), represents one of the most difficult and costly separations in typical plant circuits. Since 1969, the screen bowl centrifuge has offered an economical alternative to filtration/thermal dyer combinations. The performance of screen bowl centrifuges has been continuously modified and improved to dewater not only coarser coals, but also today's variety of ultrafine material. Test comparisons with alternative methods show the screen bowl centrifuge to be most cost effective and efficient when all factors are considered.

Jan 1, 1984

Jan 1, 1897

Jan 1, 1968

Jan 1, 1891

By N. F. Mott

Jan 1, 1961

By John W. Cahn

IT is well established that the pearlite reaction is a nucleation and growth reaction, and that pearlite nucleates on grain boundaries or intersections of grain boundaries. It is also known that while the

Jan 1, 1958