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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

By Lloyd Williams, R. E. Hershey, B. W. Gandrud

"1. The investigation shows that the Sewanee bed is the only bed of major importance in Marion County, 97 percent of the coal mined in the county having come :from this bed. There are coal reserves in minor quantity in the Battle Creek bed, and production from this bed depends on a few small truck mines. The Richland bed, or Lower Sevanee has been mined in the past, but no coal has been produced from it in late years. There are no production records of any other beds in the county, although some coal has been produced from them.2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and on l,800 tons per acre-foot of coal in place, are estimated to be 61 million short tons as of January 1, 1953. Of this total, 55 million short tons is in beds 28 inches and more thick. Areas in each bed ·were omitted from the estimate where available data relative to the bed characteristics are too meager to permit making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.3. Recoverable reserves of coal are estimated in beds 28 inches and more 'thick. This recovery is based on total thickness of coal in the bed (less partings 3/8-inch thick or more), rather than on the thickness of the coal actually mined. This thickness is about the minimum now being mined by hand loading onto conveyors in the Appalachian Region. The combined weighted average recovery for the Sewanee and Battle Creek beds in Marion County, as determined by this investigation, is 60.9 percent. Based on this, the recoverable reserves of coal in Marion County are estimated at 34 million tons."

Oct 1, 1955

By Mark Sheppard

This paper is the third of a series recording the results of tests made at various quarries throughout the United States to determine (1) the relation between the size gradation of feed to, and product from, primary crushers, (2) the particle shape of the crushed product, (3) the differences in gradation and particle shape produce- by different types of primary crushers, and (4) the differences in gradation and particle shape caused by crushing different kinds of stone. Progress reports 1 and 2 dealt with comparisons of different types of crushers crushing the seine tyre of stone. This report deals with relationship between feed and product of two different limestones, as to size distribution and particle shape, when crashed in the same crusher.

Jan 1, 1938

By E. C. Lane

This paper on the physical and chemical properties of crude oils from California fields is one of a series of reports on the oil-producing districts of the United States. The paper includes a short discussion of results, tabular data, and individual analyses of 16 California crude oils. Analyses of other oil from California have been published in Reports of Investigations 25954/, 26085/, 28466/, and 30747/. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting of the samples vas facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1937

By E. C. Lane

This paper on the physical and chemical properties of crude oils from California fields is one of a series of reports on the oil-producing districts of the United States. The paper includes a short discussion of results, tabular data, and individual analyses of 16 California crude oils. Analyses of other oil from California have been published in Reports of Investigations 25954/, 26085/ 28466/, and 30747/. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting of the samples vas facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1937

By J. E. Doo1ey

To process and use the heavy ends of petroleum effectively, the development of suitable separation and characterization procedures not currently available was required. A systematic procedure was developed by the Bureau of Mines using such techniques as isothermal and molecular distillation, chemical treatment, silica-alumina gel chromatography, gel permeation chromatography, and spectrometry. Using these techniques, the Bureau achieved a detailed separation and characterization of a 370° to 535° C distillate from Gach Saran, Iran, crude oil. Such a systematic procedure and the semiquantitative data resulting therefrom should be of value in selecting feedstocks and in optimizing petroleum processing operations.

Jan 1, 1973

By H. C. Carpenter

Data are presented comparing results obtained with 17 different catalysts in hydrogenating crude shale oil to gasoline in single-pass operation. A method is described for predicting the maximum yield of gasoline obtainable at constant pressure for each catalyst from results of a limited number of experiments at different temperatures. Operating variables have considerable influence on yields and properties of products. With most of the catalysts, at operating temperatures below 890° F. liquid yield exceeded 100 volume-percent. Above this temperature the volume of liquid product decreased rapidly. Maximum gasoline production in most instances was achieved at a temperature higher than that at which the maximum volume of liquid product was produced.

Jan 1, 1959

By S. J. Aresco

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grindability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions3 issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor; if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1968

By A. D. Hahn

The Federal Bureau of Mines examined ilmenite-bearing sands in southern Texas as part of a program to discover sources of supply for the domestic titanium industry. Deposits were examined from May 1956 through January 1959 in the outcrops of sandstone beds in the Jackson group of Eocene formations in Lee, Burleson, Fayette, and Starr Counties on the Gulf Coastal Plain; in alluvial valley fill in Brewster County in southwest Texas; in the sand beaches of Matagorda Peninsula and the Galveston, Padre, and Brazos Islands--part of the offshore chain of barrier islands along the Texas coast; and in unconsolidated sediments in Willacy County on the Rio Grande delta in the southeast Texas.

Jan 1, 1961

By A. J. Kraemer

This report on the physical and chemical properties of typical crude oils of California is the 'eighth in a series on the producing districts of the United States. It includes discussion of results, tabulated data, and individual analyses of typical California crudes. Additional analyses of crude oils from the fields of Fresno, Kern, Los Angeles, Orange, end Ventura Counties will be published later in another Serial of the Bureau, but the summary tabulations are presented here. The samples represented in this report were collected over a rather wide interval of tine, the early samples having been obtained during the fall of 1919, and the most recent ones dating from the summer of 1923. It is thought that the samples are fairly representative, both of the older settled production and of the new flush production of the southern California fields.

Jan 1, 1924

By A. J. Kraemer

This report is one of a series dealing with oil-shale-operations in foreign countries visited and studied by Bureau of Mines oil-shale technologists within the past 4 years. Many oil-shale deposits have been discovered in Brazil and studied with various degrees of thoroughness. In this report the major emphasis is upon the oil-shale concessions of Companhia Nacional de Oleos Mineraes, in the River Valley of the State of Sao Paulo, because this oil-shale deposit is one of the most promising in Brazil for large-scale utilization for the manufacture of liquid fuels and other products of oil-shale processing, and because the opportunity was afforded to examine the concession area and to study mining, retorting, and. refining operations on these shales. Results of detailed analyses at the Oil Shale Research and Development Laboratories of the United States Bureau of Mines, Laramie, Wyo., are reported, Analyses and other date dealing with other oil-shale deposits in Brazil have been compiled from many sources. As many data have been reported as could be correlated to indicate the range of variation of the several types of shale end similar material. The oil-shale deposits in Brazil differ widely in size, richness of the shale, and of the oil. Some deposits are situate& more favorably for exploitation than others.

Jan 1, 1950

By T. J. Ballard

Chromite deposits in the vicinity of Louise, Troup County, Ga., were studied y the Bureau of Mines from September 1, 1942, to March, 15, 1943. They are about three-fourths of a mile southeast of Louise and 8 miles northeast of La Grange, Troup County, Ga. The existence of chromite deposits in that area has been known for more than 75 years, but no active prospecting was done until World War I. Prospecting continued intermittently' until 1928. The Bureau became interested in the deposits in connection with its strategic minerals investigations during World War II. The chromite in these deposits occurs as grains ranging from "pin-head" size to 3/8-inch and occasionally 1 inch. Some of the material is magnetic, indicating the presence of magnetite. Of the 300 samples taken during the course of the project, 266 were analyzed. Tables showing the analyses accompany this report.

Jan 1, 1948

By Jonisha P. Pollard

In restricted vertical working heights such as low-seam coal mines, workers are forced to assume kneeling or squatting postures to perform work. These postures are associated with increased risks for the development of significant knee pathologies such as meniscal tears and osteoarthritis [1,2]. Previous research has shown an increased applied knee flexion moment when kneeling in high flexion [3]. However, these models have been applied to flexion up to 140° which neglects contact between the thigh and calf which occurs beyond 140°. In addition to thigh-calf contact, when kneeling near full flexion there may be additional contact between the heel and gluteal muscles. To the author?s knowledge, heel-gluteus contact has not been previously investigated, but thigh-calf contact has received some attention. Zelle (2007) reported thigh-calf contact forces up to 30% bodyweight (BW) [4]. Zelle (2009) reported decreased knee forces when accounting for thigh-calf contact [5]. Caruntu (2003) reported erroneous force and moment estimations when thigh-calf contact was neglected from models to determine muscle and ligament forces [6]. In this study thigh-calf and heel-gluteus contact forces were quantified to determine their effect on the externally applied flexion moment in high flexion.

Jan 1, 2009

By R. L. Crosby

From studies of wrought magnesium alloys containing rare-earth elements, data are presented on the mechanical properties of the alloys at room temperature and at temperatures of 100°, 200°, and 300° C. Results of studies of the solid-solubility of cerium and zirconium in magnesium as determined by electrical resistance measurements are also discussed and are compared with those of other investigators. The strength of magnesium-cerium alloys did not increase with the addition of vanadium and titanium dioxide. The addition of zirconium increased the tensile strength of the alloys as much as 10,000 p.s.i. at room temperature, but this increase diminished above 100° C.

Jan 1, 1962

By A. J. Kraemer

This report on the physical and chemical properties of crude oils of California is one of a series on the producing districts of the United States. It includes a short discussion of results, tabulated data, and individual analyses of California crudes. Analyses of crude oils from the fields of Fresno, Kern, Los Angeles, Orange, and Ventura Counties have been published in Serials 25952 and 26083. The analyses reported in this paper corer samples that were obtained subsequent to the publication of Serials 2535 and 2608. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting of samples was facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1927

By John B. Knaebel

This paper, describing the milling operations of the St. Joseph Lead Co. at Balmat, N. Y., is one of a series of similar papers being prepared by the United States Bureau of Mines on practice at various mills in the United States, Canada, and Mexico. The company also operates a mine end mill at Edwards, 12 miles northeast of Balmat. Mining practice in the district, as exemplified at the Edwards mine, is described in another information circular of the Bureau of Mines.3 The writer gratefully acknowledges the generous cooperation of the company officials which made this investigation possible, and wishes to thank R. J. Mechin, manager, P. W. Wolf, mill superintendent, and F. G. Kuehl, assistant mill superintendent, for their helpful assistance. Especial thanks are due J. S. Brown, geologist, for supplying information on the characteristics of the ore, and to C. F. Jackson, principal mining engineer, U. S. Bureau of Mines, for helpful suggestions.

Jan 1, 1932

? CAGER, CAGE RIDER, CAGE TENDER, SHAFT MEN All of the above job titles are variously associated with the handling of men and material at hoist stations. Generally, these classifications of personnel are involved with riding cages with personnel and in hoisting supplies into the mine. Job titles and activity description will be defined in the respective chapters. ? FLOW CHART SYMBOLS [Vertical Transportation Horizontal Transportation Storage Operation Delay ]

Jan 1, 1975

Apply state-of-the-art monitoring and computer systems technology to remotely monitor geostructural data and evaluate ground conditions in near real-time. Background Recently, the coal mining industry has progressed dramatically from a labor-intensive industry to highly mechanized and automated systems achieving significantly higher production rates. In underground longwall coal mines, production and face advance rates have increased by almost tenfold in the last 15 to 20 years. With increasingly high advance rates, geologic anomalies which affect rock mass quality are encountered more frequently, far exceeding the current rate at which ground control information can be processed and analyzed. As a result, mine operators find themselves with insufficient time or resources to cope with the rapidly changing ground conditions. To keep up with the technological advancement in mining and the associated ground control problems, the Bureau of Mines is conducting a multi-phase research pro¬gram to implement a computer-assisted Ground Control Management System (GCMS). Research is ongoing at present, but when completed the system will be designed to 1) monitor and evaluate data on rock properties, geologic conditions, and rock mechanics data from underground sensors in near real-time; 2) interpret the analyses to evaluate the interaction between various critical ground control parameters; 3) assess the structural integrity of the mine; and 4) determine failure modes and provide recommendations for control measures, design modifica¬tions, and alternative support procedures. The system will be expanded into its full capability during various phases of this research program.

Jan 1, 1991

By D. B. Taliaferro

Information regarding the pores or voids in reservoir rocks is vitally important in the scientific extraction of petroleum from natural underground reservoirs, and petroleum technologists concerned, with subsurface, conditions have devised various methods that give reasonably accurate information as to the porosities of oil and gas-bearing sands.5/ In this, work, several investigators have made use of the experience of the ceramic and other industries. The method of determining the effective porosity of oil sands described in this report falls within the general classification of gas-expansion methods. It was devised and developed at the United States Bureau of Mines Petroleum Experiment Station, Bartlesville, Okla., as a part of the research dealing with fluid and energy relations in reservoirs and improved oil-recovery methods. The apparatus and procedure are well adapted to the requirements of the Bureau, and the following detailed description has been prepared so that others may make use of the information. A tabulation at the end of the report gives the results of several hundred porosity determinations for oil sands in fields of 11 States.

Jan 1, 1937

By D. B. Taliaferro

Information regarding the pores or voids in reservoir rocks is vitally important in the scientific extraction of petroleum from natural underground reservoirs, and petroleum technologists concerned. with subsurface conditions have devised various methods that give reasonably accurate information as to the porosities of oil and gas-bearing sands.5/ In this work, several investigators have made use of the experience of the ceramic and other industries. The method of determining the effective porosity of oil sands described in this report falls within the general classification of gas-expansion methods. It was devised and developed at the United States Bureau of Mines Petroleum Experiment Station, Bartlesville, Okla., as a part of the research dealing with fluid and energy relations in reservoirs and improved oil-recovery methods. The apparatus and procedure are well adapted to the requirements of the Bureau, and the following detailed description has been prepared so that others may make use of the information. A tabulation at the end of the report gives the results of several hundred porosity determinations for oil sands in fields of 11 States.

Jan 1, 1937