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By Donald F. Smith

This report describes the construction and calibration of two ice calorimeters and includes results of high-temperature heat-content measurements, made by the Federal Bureau of Mines, on rubidium fluoride, hafnium tetrafluoride, cesium chloride, and cesium iodide. The heats and entropies of fusion of rubidium fluoride, cesium chloride, and cesium iodide have been calculated at their respective melting points using equations derived from the experimental heat-content data. Hafnium tetrafluoride did not melt within the range of temperatures investigated. Heat and entropy of transition of cesium chloride from the alpha to the beta form were also determined. INTRODUCTION Free-energy data usually afford the cheapest and quickest means of determining the feasibility of experimentally untested reactions. For known reactions, free-energy data show the variation of the equilibrium constant with temperature and make it possible to calculate, without experiment, the maximum ratio of product to raw material for a given chemical process.

Jan 1, 1961

By David L. Shuck

This report was prepared for the Bureau of Mines to describe the current methods of design, construction, and development of wells for in situ leaching of uranium. The discussion includes the alternatives for well design drilling equipment and fluids, grout formulation and emplacement, well integrity testing and repair, and well development and stimulation. Current practice in these areas was determined through interviews with eight operators of commercial scale in situ facilities and is also discussed. Based on this information plus the authors' experience, recommendations are made regarding well design, construction, and development tor in situ leaching.

Jan 1, 1982

By C. B. Manula

This report is volume 5 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report describes the Subsidence subsystem of the Master Design Simulator. This subsystem uses the finite element method to simulate ground movement caused by an advancing mining face in an underground coal mine. The model is structured around the concept that the ground mass is a layered media of different thicknesses and material properties. Gob areas are considered to be unfilled with broken rock at the beginning of mining. After mining starts, the gob areas are filled with broken material which provides resistance to the lowering of the overlying strata. The model is tied to the Geology and Reserves subsystem, but it can also operate as a free standing routine. A case study is presented illustrating the application of the model. A detailed user's manual, including a program listing, is included in the appendices.

Jan 1, 1974

By G. W. Jones

As a part of its general safety program the Bureau of Mines has investigated various means useful for the elimination or mitigation of the explosion hazards in connection with combustible gases incident to the mining industry. Information has been obtained relative to the explosibility of numerous simple and complex gaseous combustible atmospheres. Although experiments along this line have pertained largely to combustible gases in the mining and allied industry, considerable information has been obtained relative to the explosive hazards of combustible gases and vapors used as anesthetics.

Jan 1, 1939

By G. W. Jones

As a part of its general safety program the Bureau of Mines has investigated various means useful for the elimination or mitigation of the explosion hazards in connection with combustible gases incident to the mining industry. Information has been obtained relative to the explosibility of numerous simple and complex gaseous combustible atmospheres. Although experiments along this line have pertained largely to combustible gases in the mining and allied industry, considerable information has been obtained relative to the explosive hazards of combustible gases and vapors used as anesthetics.

Jan 1, 1939

By J. P. Powell

The increased costs of exploration and drilling of new oil fields and the continued success of water flooding in nearly depleted oil fields have created a demand for information on the results obtained from individual projects. The Bureau of Mines has published several reports concerning water-flood activity in the Mid continent area and at the request of the industry has continued to collect and disseminate this information. This report was written in response to these requests. It describes in detail the water-flooding projects in Anderson, Franklin, Linn, and Miami Counties, Kans., and includes methods of water treating and the results obtained. The production histories of each county and many water-flood projects are shown graphically from the date of the first development. Maps of most of the major projects, showing their status as of January 1, 1953 are presented also. The practice of injecting water to stimulate oil production was legalized in Kansas in 1935, and the first water-flooding project authorized in this four-county area was initiated by the Texas Co. in December 1935 in Linn County, Forty-nine projects2/ initiated in the area to January 1953 are estimated to have recovered approximately 10 million barrels of oil that could not have been produced by methods used previously. About 7,900 productive acres had been, or are, flooded by these projects, and approximately 1.36 million barrels of water had been injected.

Jan 1, 1953

By N. A. Eilertsen

Procedures of mining high-calcium limestone underground at the Kimballton mine of the Standard Lime and Cement Co. in Giles County, west-central Virginia, are described. Drilling and blasting procedures arc discussed in detail, and direct mining costs are tabulated in percentage of total cost. Output, about 1,725 tons of limestone a day, is attained with heavy trackless equipment by the room and pillar method of ruining; modified by benching floors. Operating features include underground air compression, electric-eye control of curtained doorways, use of a single jumbo drill rig for all drilling, and an effective plan for maintenance of equipment. The company's safety program has contributed to an outstanding safe mining record. The mina is integrated with a plant on the property which converts the stone to metallurgical and chemical grade lime.

Jan 1, 1964

By A. C. Smith

The U.S. Bureau of Mines constructed a large-scaJe facility to study the self-heating of a large coal mass under conditions that simulate a gob area of a mine. The insulated coal chamber can hold up to 13 short tons (st) of coal and is provided with a forced ventilation system and computer-controlled temperature and gas measurement systems to monitor the heat and mass transfer phenomena that occur in the coalbed. Three experiments were completed with high-volatile C bituminous coals that exhibited high spontaneous combustion potentials in laboratory-scale tests. In the first two tests, a sustained heating was not achieved. In the third test, temperatures throughout the coalbed increased steadily from the start, with thermal runaway occurring near the center of the coalbed after 23 days. The thermal reaction wne then moved toward the front of the coalbed. The results of these tests showed that the self-heating of a large coal mass depends not just on the reactivity of the coal, but also on the particle size of the coal, the freshness of the coal surfaces, the heat-of-wetting effect, and the availability of O2 at optimum ventilation rates.

Jan 1, 1991

By Scott Turner

Within recent years , people have begun to realize the importance and significance of the mining and allied industries . The leading part the engineer plays in civilization is becoming recognized . However , accurate quantitative knowledge of the industrial importance of mining is still seldom possessed except by those close to this business . It is true that there are a few who go to the extreme and represent the whole progress of civilization as a reflection of man's gradual mastery of mineral utilization , but on the whole , the magnitude of the industry is underestimated . The uncertainties of mining , as evidenced by the variable results of prospecting on surface or underground , in an unknown new field or from the bottom levels of a mature mine , the ins and outs of tonnages and metal contents , the possibility of a widespread or even a sudden change between cost and realization-price , add to its picturesqueness and make mining attractive to some . To many , the fact that results are generally more uncertain and less predictable than in other industries lends added charm . The following pages may serve to call attention briefly to the importance of mining relative to other industries in the United States , in Canada , and in the world . Ordinarily , the annual primary mineral production of the United States amounts to about 5 billion dollars . The average for the last five years has been a little over 5 billion dollars . Last year , sadly enough , it was less than 34 billions . Just now , we are on the decline , and have been for the past two years . In Canada , the 5-year average was about 268 million dollars . Last year it was 227 million . Due in part to gold output ( in 1930 , for the first time , Canada's gold production exceeded that of the United States ) , the Canadian average is holding up better than ours . It has been estimated that the average world mineral production over the past five years has amounted to about 12 billion dollars , while in 1931 it was less than 8 billions . The mineral industries are as indispensable for the conduct of modern society as are those of agriculture , but , in the United States at least , they receive far less recognition from the Government . With us , agriculture is fostered by a great department that is maintained by enormous appropriations , while the mineral industries get but little financial support . In the United States , in the calendar year 1930 , the value of production by these two industries were as follows : to 1 . Agriculture ( inclusive of forestry ) 9.9 billion dollars ; mining 4.8 billions ; ratio 2 Direct appropriations by our Federal Government were 109 million dollars to agriculture and 2.8 million to mining , a ratio of 39 to 1. Obviously this is out of balance to the extent of 19 to 1 in favor of agriculture .

Jun 1, 1932

By M. R. Geer

American and European practices in cleaning fine coal are strikingly different. The tables, launders, classifiers, and pneumatic devices used in America are seldom employed in Continental Europe, where much of the fine coal is cleaned in feldspar jigs, often supplemented by froth flotation of the extreme fines. This difference in choice of cleaning equipment may be fortuitous, but in large measure can be attributed to a difference in economic factors. Coal being more costly in Europe, there is greater emphasis on efficient cleaning of all sizes, including the extreme fines, and it is common to produce a high-ash middling for "on-site" consumption to avoid any waste of fuel value. The feldspar jig has been found advantageous under these conditions. In the United States fuel coal must be prepared as cheaply as possible, and metallurgical coal must be prepared as efficiently as possible; thus in both branches of preparation practice, any cleaning device that promises greater economy or higher efficiency warrants consideration. The feldspar jig, as employed in Europe, has a much higher unit capacity than the wet table used so extensively here and therefore offers economy in the capital costs of a washery through saving in space. As pointed out by Vissac,4/ the jig operates under automatic control, and therefore can cope with fluctuations in quality of feed. Maintenance costs for a single, large-capacity unit, such as the feldspar jig, would be expected to be lower than those for a battery of low-capacity cleaners. These considerations led the Bureau of Mines to undertake an investigation of the feldspar jig to determine its possible usefulness in this country.

Jan 1, 1958

By L. G. Marshall

Gypsum mining and processing has been one of the principal industries in Iowa for more than 75 years. For most of that period, Iowa has ranked among the five leading States in the production of crude gypsum and of calcined-gypsum products. The Fort Dodge area accounted for 11 percent of the gypsum products produced in the United States in 1956. Before 1927 the output by the major companies came from underground operations, using a room-and-pillar stoping method. At present, all production comes from quarries. The quarry methods at the various properties are similar. This paper describes the quarrying, methods employed in the district and the type of equipment used by each company. The sections on history and geology are, in part abstracts from State annual reports and an Iowa Geological Survey publication.3/

Jan 1, 1959

By Jerry W. Ramsey

The Bureau of Mines examined a low-, a medium-, and a high-volatile Pennsylvania anthracite by densimetric methods using four mesh si.s of each anthracite. Using high-pressure mercury the macropore volumes and distributions of these pore volumes determined, densities in mercury were calculated, and specific pore vo1.r. ware obtained from these mercury densities in conjunction with helium densities. The helium densities were also used with the ultimate analyses of these anthracites in calculating structural parameters by statistical densimetric methods. The effect of 106 or 108 rads of gamma irradiation in the presence of air and in vacuum upon the properties studied with two mesh sizes of each anthracite. Results of the statistical densimetric method seem to show some breakdown of condensed ring structural units at the lower irradiation level, with subsequent polymerization at the longer period of gamma irradiation. The structural parameters obtained also indicated that in going from high- to low-volatile anthracite, either the number of condensed rings per structural unit increased, or the degree of polymerization increased.

Jan 1, 1965

By E. V. Potter

"INTRODUCTION The oscillator and amplifier system described in this paper was developed specifically for driving sound generators of the type developed by H. W. St. Clair and described by him in an article 3/ published several years ago in the Review of Scientific Instruments.Nevertheless, with little or no alteration it can be used to drive any vibrating system in which the vibrating member must be driven at its resonant frequency; the only restrictions are that the driving mechanism be electrical in nature and that the vibrating member be accessible so that some type of pick-up can be coupled to it. Operation of the automatic frequency-control element in the oscillator, however, depends entirely on the operating characteristics of the vibrating member; therefore, in order to completely explain the operation of the circuit, it will be necessary to describe the construction and operation of the vibrator used with it. Only the essential features and characteristics of the vibrator will be described in this article, and the reader is referred to St. Clair's 4/ report for further details."

May 1, 1943

By D. B. Dow

The presence of sulphur compounds in petroleum and its products is, generally speaking, undesirable, and the problems involved in removing such compounds are of great importance to the petroleum refiner and to the manufacturer of gasoline. There are several types of these compounds which are dissimilar in physical and chemical characteristics, as evidenced by different objectionable features which they exhibit, and special treatments have been developed to meet conditions existing in various products. This paper deals with the treatment of natural-gas gasoline for the removal of certain sulphur compounds which, if not removed, impart on objectionable odor and in addition badly discolor the product. The presence of this particular type of sulphur compounds is detected by the "doctor" test.* In some instances natural-gas gasoline is purchased on "doctor" test specifications, and the ordinary purchaser, while not buying on "doctor" specifications, is insistent in his demand for a water white product. Gasoline which fails to meet the "doctor" test, if not received by the buyer within a few weeks after time Of manufacture, may be "off color" enough to warrant a deduction from the market price.

Jan 1, 1923

By W. R. Crane

Subsidence and ground movement are phenomena common to and attendant upon practically all large-scale mining operations, and under certain conditions may occur in all workings, large and small. The interpretation of the cause of failure in rock masses involves a study of the nature of plants of weakness common to all rocks. The dominating planes of weakness can readily be determined by observation in any given locality, and in order of importance in the study of subsidence are (1) faulting planes, (2) bedding planes, (3) joint planes, and (4) other prominent planes of weakness such as thrust and shear planes and contacts. This report has mainly to do with the third item, joint planes, and is a preliminary statement which t to be followed by a more complete report in bulletin form.

Jan 1, 1931

By F. S. Wartman

The presence of magnetite, either dissolved or suspended as solid crystals, in slags from the copper reverberatory furnace is a frequently mentioned cause of an abnormally high copper content in those slags. The presence of this oxide in the slag is to be expected, since it is present in appreciable amounts in both converter slag and roaster calcine which comprise a considerable proportion of the furnace feed. Magnetite is also a product of some of the furnace reactions. These abnormal losses result in several ways. Magnetite is supposed to favor the formation and retention of copper ferrite, in the slag. Crystals of solid magnetite suspended in the slag are objectionable-because they make the slag less fluid and often entrap globules of matte. Frequently these crystals settle into a layer at the slab-matte interface which may have such mechanical strength as to create a false bottom and interfere with furnace operation by preventing separation of matte from slag. Magnetite may, by crystallizing on the furnace bottom, build the bottom to such a level that the furnace can no longer be operated.

Jan 1, 1928

By W. M. Dressel

In producing feed for a lead blast furnace, concentrates analyzing 70 to 80 pct Pb are sintered to produce a physically acceptable low-sulfur product which contains only about 50 pct Pb. Mixtures of PbS with varying amounts of SiO2, CaO, Fe 20., and ZnS were heated in an oxidizing atmosphere at 1,000° C; the products were cooled and examined to determine the problems involved in producing sinter with substantially higher lead levels. Microscopic and electron microprobe studies of the above products as well as experimental and commercial sinters indicate that sinters consist essentially of lead silicates, lead-zinc silicate, calcium zinc silicate, and spinel (ferrite). Lead oxide and lead sulfate areas appear to result from insufficient mixing of the materials prior to sintering. The data give an insight into the process and show that sintering results from a complex interaction of all constituents and that sintering is not simply a matter of diluting the mixture to control the oxidation of lead sulfide.

Jan 1, 1975

By J. J. Pfeiffer, J. W. Myers, A. A. Orning

A study was made of the feasibility of using washery refuse in the manufacture of lightweight aggregate for building materials . Preliminary caking and burning tests showed that the refuse could be converted into lightweight aggregate but that refuse passing a No. 14 U.S. Standard screen could not be used without additional processing . The aggregate was prepared by pelletizing the refuse and burning out the carbonaceous material on a chain- grate in a refractory - lined furnace . A small stationary - grate furnace was used to study the process variables involved and establish optimum ignition and combustion conditions . Maximum ignition rates were obtained at air rates of approximately 200 lb per sq ft hr , but air rates of 450 or higher were required in the burnout period to obtain temperatures high enough to sinter the ash . The data obtained from this unit were used as a guide in the operation of the chain- grate furnace . In the chain - grate furnace , satisfactory results were obtained by using primary air rates of 200 lb per sq ft hr in the ignition zone and 500 lb per sq ft hr in the burnout zone . The ignition- zone air was preheated to 500 ° F , but the air for burnout was not preheated . A total of 2-1/2 tons of aggregate was prepared in this unit and made into experimental block . A commercial development based upon the results of this study yielded a product which met the ASTM specifications C 130-42 for lightweight aggregate , and blocks made from the aggregate were of good color , durable , and light - inweight .

Jan 1, 1964

By Oliver C. Ralston

The nonmetallic minerals work of the Bureau of Mines started with the organization of the Mineral Technology Division in 1912. A special experiment station devoted to the mining, preparation, and processing of nonmetallic minerals was established in 1923 at New Brunswick, N. J., and concentration problems on nonmetallic minerals of all kinds also were studied at the Mississippi Valley Experiment Station at Rolla, Mo. In July 1936 the Nonmetals Division was organized, and in May 1937 the Nonmetallic Minerals Experiment Station at New Brunswick, N. J., was moved to and made a part of the new Eastern Experiment Station at College Park, Md. At present the Nonmetals Division operates at three points: The Eastern Experiment Station, College Park, Md., which is headquarters for the division chief; the Southern Experiment Station, Tuscaloosa, Ala.; and the Northwest Experiment Station, Seattle, Wash., where coal washing and preparation studies are included with those on nonmetallic minerals. Sand, gravel, and aggregate work is carried on by the Mining Division, as sand and gravel preparation are intimately associated with mining methods. The Economics Branch of the Bureau of Mines also prepares occasional papers on nonmetallic technologic subjects in connection with the presentation of statistics on a particular industry and reviews of the mineral industry in foreign countries for use in the monthly publication, "Mineral Trade Notes."

Jan 1, 1937

By M. R. Geer

The cleaning of fine coal, particularly for metallurgical use, is receiving greater attention. An increase in the proportion of fine coal in the run-of-mine product has been created by changes in mining practice, and a concur-rent deterioration in the quality of the fines has occurred because of more widespread full-seam mining. These two factors, augmented by the depletion of premium beds of metallurgical coal in some areas and the resulting shift to "dirtier" beds, are providing the impetus for adoption of improved cleaning techniques. For example, froth flotation, which has been used for years in a few preparation plants, now is gaining more rapidly in acceptance. Similarly, the dense-medium cyclone, which is used widely in Europe for making difficult separations, recently has been introduced to the United States. Regardless of the cleaning process employed, the finer sizes of coal can be treated with maximum effectiveness only when they are removed from the run-of-mine product and treated separately. No present process can treat the full range of sizes together with complete effectiveness. Flotation is applicable only to the coal finer than a top size ranging between 14-and 48-mesh, and cyclones require removal of all material finer than 0.5 to 0.3 mm. from the feed. Thus, the trend toward more-effective cleaning of the fine coal imposes the attendant problem of fine screening. Whereas in the past there was little need to screen finer than about l/4-in., present developments indicate that fine screening will become increasingly prevalent.

Jan 1, 1960