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By P. G. Clites

This study was conducted to determine the patterns of heat transfer to water-cooled copper crucibles during vacuum arc melting. Values of heat flux from the ingot to the crucible were determined during nonconsumable electrode vacuum arc melting of zirconium and during consumable electrode vacuum arc melting of titanium) zirconium) and steel. The results of these studies con-firm the existence of a high thermal resistance between the ingot and the crucible wall which results from the shrinkage of the ingot as the metal solidifies. Maximum heat flux occurs near the top of the ingot where maximum values of heat flux of 1.4 X 106 Btu/ft2 hr were observed during small-scale consumable electrode arc melting of zirconium and titanium. The maximum heat flux for consumable electrode arc melting of 8-inch-diameter ingots was 0.5 X 106 Btu/ft2 hr. The effects of electrode material) electrode diameter) arc current) and arc potential on heat flux from the ingot to the crucible were studied. Data were also obtained on crucible wall temperatures and on the effect of very narrow annular water jackets.

Jan 1, 1967

By W. N. Poundstone, W. M. Merritts, B. A. Light

A joint investigation by the Bureau of Mines and the Christopher Coal Co. at the Humphrey No. 7 mine, operating in the Pittsburgh coalbed in northern West Virginia, was undertaken to gain more insight concerning the hazardous emission of methane gas in mining. This report describes the equipment, procedure, and results. Horizontal bleeder holes drilled in the faces drained large quantities of methane, eliminating downtime of mining equipment. Also, larger quantities of methane were removed by forcing 14 to 25 g,.p.m. water at 25 to 200 p.s.i. 5 pressure into the bleeder holes. In one infusion test a fluorescein dye was added to the infusion water; in later mining operations, the infusion water was traced for a distance of 1,500 feet. With vacuum pump applied to the horizontal hole the gas-flow rate increased, and the methane content decreased. Tests indicated that methane and water infused in bleeder holes traveled along the bedding planes of the Pittsburgh coalbed at a faster rate than across the planes. Methane associated with coalbeds is produced by the slow decomposition of carbonaceous material in the absence of air and the presence of water. It is lighter than air and, depending on its concentration, forms an inflammable or explosive mixture with air. It is believed that methane is entrapped in and around the pores of the coal and adjacent strata--often under great pressure. In many cases where the strata have been disturbed by geologic movements the

Jan 1, 1962

By H. L. Burmeister

These properties were examined by a Bureau of Mines engineer in 1949. During 1950, these mines were studied by the Bureau to determine the possibility of increasing the production and augmenting the supply of fluorspar. As a result of this study, it was decided to core-drill the Knox-Yingling vein to test the continuation of fluorspar to a greater depth than that reached by mine workings. It also was desired to relate the present deposit with the Rosiclare formation. Development work by the Bureau of Mines was performed from February to May inclusive in 1951. Four diamond-drill holes aggregating 2,733 feet were drilled in the hanging wall of the vein.

Jan 1, 1952

By Noel N. Moebs

Five LANDSAT lineaments in the coal mining region of southwestern Pennsylvania were investigated by the Bureau of Mines to determine their geologic character, relation to subsurface conditions, and the means of discriminating one from another. The investigation included earth resistivity and very low frequency (VLF) electromagnetic traverses, soil moisture sampling, and a correlation with coal mine roof conditions. The lineaments could not be detected by the methods used, suggesting that they might be a surface phenomenon unrelated to subsurface geologic structures or roof stability in coal mine workings beneath.

Jan 1, 1987

By Robert W. Freedman

In the Bureau of Mines study, a filter with a 20-by 20-inch-square cross section was inserted into the exhaust ducting of a 4-stroke-cycle, 90-hp diesel engine, and the efficiency of removal of total particulate was measured gravimetrically as a function of time. Removal efficiencies were close to 90 pct during the main portion of several extended runs employing several combinations of filter beds. Variations in engine load had little effect on collection efficiency. Particle size as measured by a Bureau-developed online instrument centered on 0.07 m based on number count. Removal efficiency increased rather sharply for both larger and smaller particles.

Jan 1, 1979

By E. L. Litchfield

Descriptions are given of the techniques and apparatus used by the Bureau of Mines for determinations of flat plate ignition quenching distance and minimum spark ignition energy. The descriptions include discussions of reaction vessel materials, shapes, and sizes and discussions of electrode configurations. Spherical, hemispherical, or flat plate electrodes are recommended. The preferred metal in electrodes and electrode supports is stainless steel; the flat plate electrodes incorporate flanges of low electrical conductivity which are most frequently formed from glass. Various aspects of the electrical energy supply system are discussed and suitable arrangements of components are indicated. The concept of a thermal relaxation time is introduced as a basis for the choice of a minimum interspark time during the testing of a gas mixture. The following indicate the varied conditions under which these tech were utilized: Mixture pressures between 10 mm Hg and 45 psig, initial temperatures between -78° and +198° C, and gaseous mixtures representing wide ranges of cL.. D reactivity and corrosiveness. Minimum ignition energies were determined which varied from about 10-7 joule to nearly 103 joule.

Jan 1, 1967

By D. J. Parker

This report is based on data collected in and about the Liberty mine of the Liberty Fuel Co. by D. J. Parker and W. W. Kessler on December 13 and 14, 1933. An important phase of an examination to determine the general condition of a mine with respect to safety is the collection of dust samples from rock- dusted areas. Definite conclusions, based on intelligent interpretation of the analyses of such samples, can be reached only when the general condition of the mine is known. A similar examination and report were made on this property in January 1930 by D. J. Parker and R. I. C. Manning. Since that time much has been done by the management to improve safety conditions in this mine. The changes made will be noted in the course of this report. The mine is in Spring Canyon at Latuda, Carbon County, Utah, and is served by a branch line of the Denver & Rio Grande Western Railroad about 7 miles long and connecting to the main line near Helper, Utah. The writer desires to express his sincere appreciation for the many courtesies and helpful cooperation extended by Superintendent George Schultz and Mine Foreman F. W. Koelling.

Nov 1, 1934

By Paul W. Johnson

An evaluation is made of a lime-soda sinter process for extracting alumina from anorthosite. In this process, alumina is extracted by sintering anorthosite with soda ash and limestone, and then leaching the sinter with a dilute sodium carbonate solution. The sodium aluminate solution formed during leaching is separated from the residue and treated with lime in autoclaves to remove dissolved silica before alumina trihydrate is precipitated with carbon dioxide. The trihydrate is then calcined to a-alumina. Two options, dry grinding and wet grinding, are used in the sintering step. For plants producing 1,000 tons of alumina per day for the dry grinding and wet grinding options respectively, the estimated operating costs are $75.40 and $74.36 per ton of alumina when charging $2.50 per ton for anorthosite and $1.00 per ton for limestone. The fixed capital costs based on a Marshall and Stevens chemical equipment index of 240.0 are $76 million and $70 million respectively. This process, when treating anorthosite, using either option, is not competitive under current economic conditions with the Bayer process treating bauxite to produce alumina.

Jan 1, 1968

By David Montgomery

The feasibility of building a calibrator for the DuPont D-100 audio dosimeter is discussed. The desired specifications are used as guidelines but the possibility of their relaxation is also considered. Commercially available equipment is surveyed and found to not satisfy the guidelines. Several alternate concepts are investigated, and recommendations for further work are presented.

Jan 1, 1974

By A. B. Hooker, L. C. IlsLey

"Field inspections and data relative to the use of rubber-sheathed trailing cables in mines show that much cable is ruined or its probable life shortened by being overheated in service.The length of cable required to make connection from a source of supply to a machine at the face workings may be 100 to 500 feet. As a rule, the cable is carried on a reel and unreeled as required; and thus in most cases soma of the cable is not removed from the reel. The overheating generally occurs in that part of the cable which is left on the reel.Factors that determine the heating of trailing cables are:1. The size of the conductors in the cable.2. The maximum energy to be supplied through the cable, based upon the horsepower of the motor and the degree to which the motor is loaded.3. The voltage of the supply and the variation of the voltage at the receiving end.4. The time length of current flow and whether continuous or intermittent.5. The kind of current (direct or alternating).6. The amount of ca· le left or the reel.7. The type of cable used.8. The kind of reel used.In connecti0n with an investigation of the general performance of rubber-sheathed trailing callas, the Bureau of Mines has made a limited study of some of these factors, including the following points:"

Jul 1, 1931

By David M. Hyman

The Bureau of Mines has developed two experimental designs for deter- mining the volumes and relative proportions of the various gas species, particularly methane (CH4), occluded in rock salt. To date, the rock salt samples analyzed have been relatively small (400- to 1,000-gram) grab samples from Louisiana Gulf Coast domal salt mines. The results obtained are comparable to results in Polish domal salt mines, in terms of occluded gas volumes per mass of rock salt. The notable difference between the Louisiana and Polish occluded gas mixtures is in the relative proportions of the individual gas species. The two methods used by the Bureau are ballmill crushing and dissolution. Of the two, the dissolution method appears to be more versatile because it can be performed in situ. The relevance and applicability of data on the occluded gas contents of rock salt are dependent on sample size, sample collection method, geologic context of the sample, and the correlation with gas emissions that occur as a result of mining-induced fractures and pressure differentials.

Jan 1, 1982

By William O. Vanderburg

This paper describing the practice at the Wolf Pongee concentrator at Federland, Colo., is one of a series on similar subjects being published by the United States Bureau of Mines. The author acknowledges the assistance of Loach, manager of the Wolf Tongue Mining Co., and of W. G. Roseborough, superintendent of the golf Tongue mill, in the preparation of this paper.

Jan 1, 1933

By L. J. Kane

Several processes being developed by the Federal Bureau of Mines to provide new and more efficient uses for coal require practical methods for removing dust from hot gases. Filters provide such means. The efficiency of filters made of aluminum silicate fibers and porous stainless steel was determined. The results obtained with the fibers were previously reported.5 In this investigation tests were made with three porosities of stainless steel filter material (grades C, D, and E) at a gas flow of 1,000 std. c.f.h./sq. ft. of filter, temperatures of 75° and 1,000° F., and dust loadings (as represented by cumulative dust fed) of 100, 1,000, and 10,000 gr./sq. ft. of filter. Pressure drop during the runs ranged from 0.1 to 21 in. of mercury, and dust removal from 25 to 99.93 pct. Filters having the finest pores gave the greatest pressure drop and percentage of dust removal; however, their dust-holding capacity was slightly lower. Usually, their ability to remove a higher percentage of dust at the same pressure drop more than compensated for the slightly lower dust-holding capacity. With increase in temperature, for the same weight rate of flow of gas, the pressure drop increased and the percentage of dust removal decreased. The effect of temperature was probably due to the accompanying change in the linear velocity and viscosity of the gas.

Jan 1, 1961

By Richard F. Hewlett

Computing average grade and tonnage either for an entire ore deposit or for individual blocks of ore is a continuing problem in mining. As part of a research program, investigating application of statistical techniques to mine sampling, Bureau of Mines engineers at the Denver Mining Research Center have made extensive use of an electronic digital computer for developing mine sampling theory, simulation of ore deposits, and analysis of mine sample and assay data. This report is one of a series describing use of the digital computer for rapid solution of computing problems in the mining industry.3 4 Development of a computer program to compute ore reserves by the commonly used triangular method was necessary so that results could be made available for analysis within hours.

Jan 1, 1963

By Charles Vaught, Warren G. Lacefield, Ronald D. Wasielewski, Philip K. Berger, Henry P. Cole, John V. Haley, Shannon L. Price

A comprehensive review of published research was carried out to identify methods for teaching and assessing critical but nonroutine skills needed for coping with emergency situations. Computerized searches of the relevant data bases were carried out, along with identification of relevant articles and materials by personal contact with experts in many fields. The citations listed in this bibliography resulted from this systematic literature search and review. The computer searches and an analysis of this literature are described in technical report 1. Specific methods for assessing critical skills proficiency in aviation, medicine, organization management, the military, and other industrial/ technical workplaces were described. The potential application of these methods for teaching and assessing (1) critical first aid and (2) self-rescue and escape skills to underground coal miners in annual refresher training was explored. Research and development activities that may improve mine health and safety training were suggested. Most of the entries in this bibliography were assembled in 1984 through 1985. Study of these materials contributed to the completion of the project research that followed. This later work is reported in the project technical report 2 and the final report. This bibliography is most useful when combined with examination of technical reports 1 and 2 and the final project report.

Jan 7, 1988

By Arno C. Fieldner

Forty years have elapsed since the Bureau of Mines was established on July 1, 1910, by Act of Congress. The convocation of this Sixth International Conference of Safety in Mines Research Directors, 24 days after our 40th birthday, seems to be an appropriate time for reviewing our contributions to mine safety research and the problems yet to be solved from the American point of view. Actually research on safety in coal mines was started by the United States Government in the Technologic Branch of the U. S. Geological Survey of the Department of the Interior in 1908, as a result of a succession of disastrous coal mine explosions in which many lives were lost. In 1910 this work was transferred to the newly created Bureau of Mines. 394 lives were lost annually per 100,000 men employed in the coal mines of the United States in the 5-year period ended in 1910, as compared to 203 lives lost annually in the 5-year period ended with 1949. In 1908 no safe, permissible types of explosives and no certified permissible equipment of any kind were used in American coal mines. Black powder was in universal use and open oil or acetylene lights were common in all but mines known to be gassy. Rock dusting was not practiced to limit propagation of explosions, nor was ventilation in many mines adequate, Our safety practice lagged behind that of foreign coal- mining countries and therefore one of the first steps in carrying out the Congressional Authorization of 1908 to investigate the causes of mine explosions was to obtain assistance from the leaders of mine safety research in foreign countries. At the request of Dr. Joseph H. Holmes, director of the Technologic Branch of the Geological Survey, James R. Garfield, Secretary of the Interior, obtained the cooperation of the Governments of England, Belgium and Germany in sending Captain Arthur Desborough, Inspector of Explosives in England, Mr. Victor Watteyne, Inspector-General of Mines in Belgium, and Mr. Carl Meissner, Counselor for Mines in Germany, to visit American mines and make recommendations for increasing safety and efficiency in mining coal in the United States.

Jun 1, 1950

1. Data from the Mine Safety and Health Administration (MSHA) indicate that a total of 241,502 employees worked in surface mining locations in 2003, corresponding to 212,113 full-time equivalent (FTE) workers. • Surface employees accounted for 84.6% of all mining employees. • The majority of surface employees (73.7%; n = 177,927) were mine operator employees as opposed to contractor employees. • Stone operator employees comprised the greatest percentage (27.2%; n = 65,743) of surface employees.

Feb 1, 2005

By G. S. Rice, R. V. Wheeler

"FOREWORDThe cooperative mine safety research program was carried on successfully in the year 1930 in a manner similar to that described in the report for 1929It is believed that the results of such fundamental work as is being done are unquestionably of great benefit in their application in coal-mining operations, in the saving of life and health of minera. The research result compared and checked by investigations in the two organizations, and further by large-scale tests, as in the Experimental Mine, give confidence to mine operators, miners and State mining officials in the findings of the various researches.The annual report of the contact officers of the United. States Bureau of Mines and the British Safety in Mines Research Board to the Director of the Bureau and the Chairman of the Board respectively, follows:Annual Reports for 1930 To: The Director, Bureau of Mines.The Chairman, Safety in Mines Research Board."

Sep 1, 1931

By Oliver C. Ralston, Foster Fraas

The electrostatic separation of solids utilizes the forces exerted when electrically charged particles of the solids are present in an electric field . The charges may be acquired by various means (5) , and when the acquisition or loss of charge depends on the property of the particle , separation can be obtained between particles having different properties . A property commonly utilized in present - day separators in conductance . Charging also may be accomplished by bringing the particles into intimate contact with various surfaces . This is sometimes described as a " frictional electrical effect. The charge , or specifically the polarity of the charge , in this latter case evidently depends on the property known as the contact potential , as has been explained in the discussion of a paper (7) and in several other papers (10) . Separation by this method is accomplished in two steps - a charging step , in which the particles are brought into intimate contact with an electrification surface , and a separation step , in which the charged particles are separated in an intense electric field . Descriptions of such methods may be found in the literature (2) , (7) , ( 8) . Even as early as 1909 , Blake and Morscher (2) described the charging of particles by intimate contact followed by separation in an electric field . They also state that the polarity of the electrical charge acquired by the particles depends on their composition . O'Brien ( 8) presented several designs of apparatus . He obtained electrification by means of a wiping action , either on inclined plates or in rotating cups , in which a centrifugal force was imparted to the particles .

Nov 1, 1942

By F. W. Lane

[The rapid expansion of the petroleum industry, the steadily growing use of oil fuel or steamships, the increasing transportation of oil in tankers and the extensive use of petroleum oils for many land industries, has resulted in pollution of our coastal eaters by these oils. On account of the great importance of this problem to the petroleum and shipping industries its, the Bureau of Mines, in cooperation with the American Petroleum Institute and -he American Steamship Owners Association has undertaken to ascertain the extend of petroleum oil pollution along the coasts of the United States and to indicated the principal so arcs of such pollution. Certain typical methods and devices in use and proposed for the separation of oil from water, and for the disposal of oily castes from ships and industrial plants have been studied. An attempt has also been made to point out the nature of the fire hazard resulting from oil pollution and to indicate the effect of such pollution on bathing beaches.]

Jan 1, 1924