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By Wen H. Su

Multiple seam mining and its associated problems are very serious in Southern West Virginia where poor planning or lack of knowledge in seam interaction often results in complete loss of coal properties. Several measures have been proposed to alleviate the interaction problems under various multiple seam conditions, but few of them are specific in terms of mining plan. Two parallel approaches are adopted for this paper. One is field investigation which consists mainly of mine site visits and gathering of data. The other is the two-dimensional finite element simulation of mine workings using the data gathered as input. Two typical cases which represent the past and present multiple seam mining practice in West Virginia were investigated. Much attention is focused on the interaction problems experienced and the important parameters controlling interaction. Several key parameters controlling interaction in multiple seam mining were analyzed. Proper mining plans, by which the interaction problems can be minimized, are proposed for the individual cases after a better understanding of the interaction mechanism was realized through finite element analyses.

Jan 1, 1984

By J. E. Nesset, J. A. Finch

A model of the fully-loaded condition of particle accumulation on the matrix of a high gradient magnetic separator is developed. The model accurately predicts the build-up profiles reported recently by Friedlaender et al. A powerful development from the model is that loading (volume of accumulated material per unit volume of matrix) is uniquely defined by a dimensionless group, called the loading number, NL. From direct measurements, NL proved superior to the dimensionless group proposed by Watson as a measure of loading. The fine size limit of hematite recovery is examined using NL.

Jan 1, 1980

By William Braden

IT is obvious that the choice of the method to be employed in the handling of blast-furnace slags and mattes depends upon local facilities and conditions which may indicate as advisable some particular plan. As a result of the variety of such conditions hardly any two smelters use identically the same method, though they be located only a few hundred feet apart. For instance, of the several plants in Leadville, Colorado, each has a more or less distinctive system. The same is true of Salt Lake City and vicinity. In view of this it is evident that the existing diversity of practice cannot be accepted, prima facia, as evidence

Jan 1, 1897

By Thomas P. Forbath

THE sudden realization that known sulphur reserves amenable to mining by the Frasch hot water process are nearing exhaustion focused attention on widely scattered surface deposits throughout the world. These deposits are not necessarily of lower sulphur content than ores located underneath Louisiana or Texas salt domes which usually aver- age about 30 pct sulphur disseminated in limestone matrix. Their near surface occurrence, however, renders exploitation by the Frasch process impossible. As is well known, the Frasch process depends on the presence of 500 to 1000 ft of overburden and cap rock above the sulphur deposits to permit melting underground sulphur in place by diffusing hot water under pressures of 200 to 600 psig in the formation and raising the molten sulphur to surface by air lift. This process renders possible the production of pure sulphur which is 99.5 pct pure without any subsequent treatment.

Jan 9, 1953

By K. V. S. Sastry

This paper summarizes recent research on the kinetic aspects and process behavior of agglomeration in balling circuits. The physical concepts underlying agglomeration, the mechanisms responsible for size changes during agglomeration, and a generalized population balance model for agglomeration systems are summarized. Experimental techniques for investigating the batch balling behavior and for simulating the balling- circuit operations are reviewed. Further, the effect of such operating variables as feed moisture, bentonite content, and the rate of feed addition are discussed. An approach to the computer simulation of the agglomerating circuits is shown and the importance of such models in process engineering is discussed.

Jan 1, 1977

By Robert Hunt

(New York Meeting, February, 1913.) I HAVE frequently stated that while the chemical composition of steel is important, yet even greater importance is connected with the mechanical and heat treatment of the metal. During the past year I encountered such a positive example of that fact that I deem it worth putting upon record. A prominent railway system divided an order for open-hearth steel rails between two steel works, both of which are under the control of the one corporation; giving to one about 18,000 tons, and to the other 7,500 tons of the same section and to be made under the same specifications. The rolling results obtained in the two mills varied so widely that a study of the figures is intensely interesting and serves to illustrate the advantages obtained by careful ingot casting, and, quite as pertinently, the possible benefits of careful subsequent heating and rolling with moderate reductions in the rolling process. The smaller order was rolled complete in four installments during the same months that the larger order was being made in six separate installments; but, to permit of exact comparisons, the totals of the four installments (completing the order with the mill which I will call A) are given with the totals of the first four installments of the larger order, made by the mill designated as B. These rolling results are:

Jan 5, 1913

By I. J. Jansen

Introduction The Surface Mining Control and Reclamation Act (PL 95-87) lays a new challenge before the surface mining industry by requiring that prime farmlands must be reclaimed to equivalent or higher levels of yield as nonmined prime farmland in the surrounding area (section 510d). We must now evaluate the situation and plan a mining and reclamation program that will achieve that objective. We must recognize that soil and land needs vary with intended land use and climatic setting. Also, various site conditions determine the potential for constructing a productive soil and the best procedures to accomplish that end. It is necessary to plan the land reconstruction program on a site by site basis in order to achieve the best results. Discussion The Prime Land Concept Terms like prime agricultural land have been used loosely for many years to refer to lands that are highly productive and well suited to agricultural use. The concept of what qualified as prime land varied considerably from one geographic area to another and from one person to another. The term prime farmland, as used in PL 95-87, has recently been defined quite

Jan 1, 1982

By Ichiro Ito

At present, in Japan, the application of in-place leaching technique to the mined-out stopes has been carried out at two copper mines in a comparatively large scale. These mines are the Kosaka mine and the Tsuchihata mine, both are situated in the north-east district of Japan. At first, the author would like to tell about the in-place leaching operations and their results at these two mines. Then, the problems involved in the application of in-place leaching technique to the Japanese metal mines and the possibility of the future development of this technique in Japan are referred, too. Next, as to the research works, the author would like to explain briefly about some of the important results obtained in the recent studies on in-place leaching as well as on bacterial leaching in Japan.

Jan 1, 1976

By Bennett Bates

NOWHERE in the world has cone classification in closed-circuit grinding with tube mills reached as high a state of development as on the Witwatersrand. In the development of the Far East section the necessity of fine grinding to obtain. satisfactory residues gave rise to a situation with which the cone could cope only at a great sacrifice in efficiency of tube-mill grinding. H., A. White1 recognized the limitation of the cone in his study of the theory of tube milling as early as 1915, but it was not until Ewing, Davis and. Willey2 carried out their tests at Springs Mines during 1920 that the advantages of mechanical classifiers' were demonstrated. During the fall of 1924 the writer supervised a series of tests with Dorr classifiers undertaken by Mr. White, Consulting Metallurgist, at the mill of the Geduld Proprietary Mines, Ltd., Dersley, Transvaal (Far East Rand). The importance of classification to obtain efficient tube-mill grinding was thoroughly demonstrated. The installation of classifiers of the above type that followed the test, confirmed the results of the experimental work.

Jan 2, 1926

By P. Nelson, K. L. Gunsallus, A. R. Ingraffea, J. F. Beech

INTRODUCTION Fracture toughness, KIC, is an intrinsic material property and is a measure of the energy required to create new surface area in a material. Fracture toughness measurements can be made for a wide range of rock types (Ouchterlony, 1980). As a measure of energy of comminution, fracture toughness might be used for more sensitive predictions of Tunnel Boring Machine (TRM) performance than are possible with other index measures in current use. This paper describes part of an ongoing, comprehensive, analytical/experimental program aimed at evaluation of KIC in such a role. The program includes efforts to: 1. Provide a firm analytical basis for a test specimen geometry: the core-derived short-rod. 2. Develop simple, inexpensive testing equipment and techniques. 3. Evaluate the accuracy of the above by testing rock and other materials and comparing the measured fracture toughness with those obtained by other methods. 4. Measure fracture toughness of a substantial number of different rocks from three ongoing TBM projects. 5. Compare fracture toughness results with other strength measures. 6. Compare all test results with observed TBM performance in the three projects. Presented here are summaries of all but the last of these efforts. Comparative evaluation of KIC as a more senstive rock property for TBM performance prediction will be the subject of the oral presentation and a subsequent paper.

Jan 1, 1982

By H. S. McQueen

THE insoluble residue method for the examination and correlation of limestones and dolomites, or other sedimentary rocks containing calcium and magnesium carbonates, originated and was developed in the laboratory of the Missouri Geological Survey. The numerous and ever-increasing problems in the field of applied geology, and the need for a tool or aid in the solution of them, led to experimental work with samples collected from deep wells, in the early part of 1924. The success attained, almost at the outset, with this method was so great that the method has now been developed from the state of the experimental to the realm of large-scale, every-day routine. In a previous paper the writer' described the procedure in detail and the characteristics of the residues obtained from certain Paleozoic forma-tions in Missouri. The purpose of the present paper is to discuss the economic application of the insoluble residue method.

Jan 1, 1936

By J. E. Ryan

TRONA, Calif., is a miniature urban community of some 3500 people, located on the northwest shore of dry Searles Lake in the extreme northwest corner of San Bernardino County, approximately 186 miles north and east of Los Angeles. Since it is situated on the Mojave Desert, a typically desert climate prevails with wide variations in temperature between day and night, extreme daytime summer heat, and cool to cold winters. Rainfall averages somewhat less than 4 in. per year, and dust storms are common. The rate of evaporation, however, is great, amounting to 6 to 9 ft of water per year. The extremely low humidity makes the summer heat of 110°F tolerable with only a mild, temporary discomfort.

Jan 5, 1951

By R. H. Wightman, C. D. Chandler, P. B. Nalle

SURFACE quarrying at the Crestmore Div. of Riverside Cement Co. in California was started in 1909. In the early 1920's it was considered that these deposits were nearly exhausted for the equipment available at that time, and in 1927 the company began a block caving system. This mine continued operating until February 1954. In 1941 trucks and crawler-mounted shovels had reached a stage of development that permitted reopening the quarries in conjunction with the underground mine. In 1948 surface reserves and the well developed limestone of the caving system neared depletion. To go deeper with the caving system was unattractive because of the economics, changes in physical structure of the rock at depth, and the perched water table

Jan 4, 1957

By Thomas W. Yardley

In many years' experience as a maker and purchaser of cast-iron coated pipe, I have never met with any standard form of specifications for such. Each water-works company, employing a hydraulic engineer, has, under his direction, prepared complete specifications for the particular conditions required; but I cannot find that any two are alike; and each foundry, in bidding for the supply of such pipe, makes the price to cover the conditions' required. I, therefore, have the honor of offering to the Institute a form of specifications for cast-iron coated water-pipe, that may be found useful to water-works companies and others requiring pipe of this kind. The conditions are all reasonable, and can be carried out by makers without additional cost, and with advantage to the purchaser. Section 1 gives the kind of pipe, with its general characteristics. Section 2 specifies that neutral pig-iron shall be used, since such iron possesses the strength required, and is uniform in its shrinkage. Section 5, requiring makers to give the brands of pig-iron used

Jan 1, 1890

By Carleton Ellis

The problem of the influence of hot surfaces upon gaseous combustion is one which, from a purely scientific standpoint, has engaged, for many years past, the attention of Prof. William A. Bone, of Leeds University and the Imperial College, London ; and as his recent work has been the direct outcome of earlier scientific investigation, it will be appropriate, by may of introduction, to review briefly the present position of science with respect to this important subject, as stated by Professor Bone. One may perhaps best arrive at an understanding of the term " flameless " or " surface " combustion by considering certain facts which differentiate it from the more familiar processes of

Jan 1, 1913

By Leon Banks

THE- Missouri-Kansas Zinc Corpn., operating in the Waco district, 15 miles northwest of Joplin, Mo., owns large tailing piles made during milling operations of the years 1918-28 by the Butte-Kansas, Acme, and Barnsdall mining companies, whose holdings have been purchased and consolidated under, the ownership of the Missouri-Kansas Zinc Corpn. These tailings had been considered too low in value to be worth retreating by the ordinary methods. C. Erb Wuensch, consulting engineer of the Missouri-Kansas Zinc Corpn., noted the difference in the type of tailing from upper-level and lower-level ore. The latter contained hard lime chats. He also found that mill losses had been due to particles of blende on the corners or sides of the chats and to the existence of soft, porous, cellular, lime chats containing varying amounts of blende. He conceived the idea that a quick grind in rolls or ball mills might change the type of the material so that jigging could make a clean tailing for discard and a partly concentrated product sufficient in blende content to justify the expense of fine grinding in ball mills to free the mineral entirely. A laboratory was equipped with the necessary machines and the writers were assigned the problem of developing a method of retreating the tailings.

Jan 1, 1929

By H. M. Howe, E. C. Groesbeck

Fig. 1 shows a volute aging break which developed spontaneously in a hardened and tempered steel helmet between 19 and 38 days after it had been tested ballistically. A similar break, shown in Fig. 2, developed spontaneously in a similar helmet about 40 days after the ballistic testing. In this case the rupture occurred abruptly and with a loud report. The path of rupture in this second case, though much the less regular, is the more interesting of the two, in that it is an approximation to two parallel volutes centered at the point of impact of the projectile, just below D. Several weeks later, after the photograph for Fig. 1 was taken, a similar doubling of the volute crack occurred in this helmet, starting from the end of the eyelash crack near A and spreading thence to the left contra-clockwise for about 1/2 in. The negatives from which these pictures are made have not been touched up in any way, save writing the letters on them. In both cases the trajectory of the bullet was normal to the initial surface at the point of impact, and in both the helmet passed the ballistic test without detectable cracking, under a velocity of impact not far below that which usually causes perforation. The initial surface itself was very nearly spherical throughout the region covered by the break.

Jan 1, 1920

By G. E. Archie

THE usefulness of the electrical resistivity log in determining reservoir characteristics is governed largely by: (I) the accuracy with which the true resistivity of the formation can be determined; (2) the scope of detailed data concerning the relation of resistivity measurements to formation characteristics; (3) the available information concerning the conductivity of connate or formation waters; (4) the extent of geologic knowledge regarding probable changes in facies within given horizons, both vertically and laterally, particularly in relation to the resultant effect on the electrical properties of the reservoir. Simple examples are given in the following pages to illustrate the use of resistivity logs in the solution of some problems dealing with oil and gas reservoirs. From the available information, it is apparent that much care must be exercised in applying to more complicated cases the methods suggested. It should be remembered that the equations given are not precise and represent only approximate relationships. It is believed, however, that under favorable conditions their application falls within useful limits of accuracy.

Jan 1, 1942

By J. H. Canterford

The adsorption of uranium onto Wyoming bentonite was measured in carbonate media over the pH range 8 to 11. Uranium was removed from solution onto the solids by a rapid reaction, proposed to be adsorption of the anionic uranyl tricarbonato complex onto edges of the clay platelets, and a slow reaction that may be precipitation of a hydroxide. The changes in uranium content of the aqueous and solid phases of a uranium ore carbonate leach slurry were also measured as the slurry was progressively diluted. There was an increase in the uranium content of the solids as the pH of the suspension was lowered, as observed with the Wyoming bentonite. Results indicate the conditions that should be met with respect to pH control to prevent the problem of excessive uranium adsorption in the counter-current decantation washing circuit of a conventional leaching process, as well as in the leaching and restoration phases of carbonate solution mining.

Jan 1, 1985

Jan 4, 1951