Search Documents

By D. S. Kingery

Experiments initiated by the Bureau of Mines on August 26. 1969, and recent work of others, have demonstrated the effectiveness of ventilation for controlling concentrations of respirable coal mine dust. Substantial reductions in dust concentrations have been attained by increasing the volume and rate of air movement across the face and by controlling the airflow pattern. Ventilation experiments conducted by the Bureau using high-pressure fans as auxiliary ventilation units showed that lace-generated dust could he effectively controlled in five mines employing continuous mining machines. Additional data was obtained on industry installations in two mines using similar ventilation systems. By maintaining an airflow approaching 100 fpm across the entry, the experimental system reduced the concentration of respirable dust by factors as great as 6.4. In all mines where the system was used the face-generated dust concentrations were reduced to below 3 mg/m3. Total respirable dust in two cases was above the 3 mg/m value because of the dust content of the intake air. In some mines. depending upon the type of coal being mined and other dust control factors in use, it was possible to Obtain concentrations of less than 2 mg/m Although the technology for the application of the dust control system investigated is readily available, it is evident that additional engineering studies should he made in each mine where the system is to be applied.

Jan 1, 1969

By O. M. Bishop

"SUMMARYAs a result of the increased demand for fluorspar during the war, the Bureau of Mines investigated numerous fluorspar properties in the southern Illinois field, which is centered in Rosiclare. Among these the J. J. Shelby 40-acre tract on the western edge of the district presented favorable factors that caused it to be chosen /or exploration.H. G. Spiller, formen lessee of the property, had explored the Shelby vein by means of an adit level and winze, and showed it to contain goad values in zinc and fluorspar at the depth explored. A diamond-drill hole with which Spiller explored the vein 78 feet southwest of the winze, however, failed to cut ore. After studying the field evidence, the Bureau concluded that the vein merited further exploration, particularly at a depth of about 440 feet, where the Fredonia limestone would form the foot-wall of the vein and the hanging wall would be the competent Cypress sandstone.Between October 17, 1944, and March 26, 1945, three diamond-drill holes were bored for a total inclined depth of 1,592 feet. Holes 1 and spaced approximately 500 feet apart, explored the vein at 440 feet 4 below the surface. The economic mineralization existed in the vein where cut. Hole 3 cut the fault at approximately 300 feet below the outcrop but failed to find any vein matter except stringers of calcite with small amounts of pyrite."

Apr 1, 1947

By T. F. Anstett

The Bureau of Mines evaluated the potential availability of chrysotile, amosite, and crocidolite asbestos from 42 properties in market economy countries. This resulted in the development of tonnage-cost relationships indicating the quantity of grades 3 through 7 asbestos at various average total costs of production at 0% and 15% rates of return on invested capital. The availability of grades 2 and 8 was also evaluated, but since each is produced at only one property, no analytical results were given. Total demonstrated recoverable chrysotile fiber potentially available of grades 3 through 7 from the 42 properties evaluated follow: 1.59 million t, 21.00 million t, 16.74 million t, 15.54 million t, and 19.27 million t, respectively. The total amount of crocidolite is 1.69 million t. Owing to the good potential for discovery and development of new deposits, long- term availability of fiber of all three types is not in jeopardy. However, many of the crocidolite properties evaluated in the northern Cape crocidolite field of South Africa have relatively small demonstrated resources, and new deposits will have to be exploited by the late 1990's to sustain projected levels of production.

Jan 1, 1985

By H. Polat, Q. Hu, M. Polat, S. Chander

"The electrostatic charge on spray droplets of ionic surfactant solutions and coal particles was measured and the results were correlated with the dust collection efficiency. When various surfactant were added, the magnitude of the droplet charge increased significantly and it was observed to be a function of surfactant type and concentration. The concentration of maximum droplet charge coincided with surfactant concentration where maximum collection efficiency was observed for these surfactants. Particles of coal also carried substantial amount of charge magnitude of which seemed to be a function of coal rank.Based on the results presented in this paper, it was concluded that ionic surfactant primarily act as a strong electrostatic charge inducer for droplets. Due to interactions between these highly charged droplets and naturally charged particles, the efficiency of droplet-particle collisions play a primary role when compared to the wetting and engulfment phenomenon which could only follow a successful collision. INTRODUCTIONWater spray are widely used to suppress airborne dust in mine atmospheres (Walton and Woolcock, 1960; Kobrick, 1970; Hamilton, 1974; Jayaraman et al., 1986). Several investigators have considered the use of surfactants to enhance the effectiveness of water sprays especially for difficult to wet particles such as those of coal (Glanville and Wightman, 1979). The capture of dust particles by water droplets involves droplet-particle collisions, adhesion of particles to droplets, and engulfment of particles into droplets. Surfactants affect these sub processes through their influence on droplet charge, surface tension, and wetting. The last two mechanism have been thoroughly studied in recent years (Walker et al., 1952; Cohen and Rosen, 1981; Glenville and Haley, 1982; Chander et al., 1988; 1991). However, little attention has been paid to the role of electrical charge on particles and droplets on the collision and adhesion of spray droplets and dust particles."

Nov 1, 1995

By A. R. T. Dennues

"INTRODUCTION There are presented in this report the results of limited studies by the Bureau of Mines of the firedamp safety of some powder-powered tools proposed for use underground in coal mines. This study was made to obtain general information and specific technical data for a cable splicer and some rail punches now commercially available, the aim being to keep abreast of developments and to anticipate hazards.ACKNOWLEDGMENTSAcknowledgments are made to the Mine Safety Appliances Co., Pittsburgh, Pa., for supplying equipment for these tests, and to the Pittsburgh Coal Co. for making possible observations of the use of these tools in coal mines.The assistance of other members of the Explosives Division is acknowledged: J. E. Crawshaw, for examination of ammunition and, propellant powders; H. L. Wilson, for analyses of the natural gas used in the gallery and Jerome C. P. Weinheimer and Martin Bashel, for conducting the gallery tests.GENERALDescriptions of the DevicesPowder-powered tools of the type tested utilize the energy of charge of,propellant powder accomplish tasks. They are essentially small guns adapted to special work. Of the family of such tools now commercially available from one manufacturer, two have been proposed for use underground in coal mines, namely a cable splicer known as model TI and two models of rail punch known as R40 and R60. These tools employ blank-cartridge ammunition and special projectiles to accomplish the work indicated by these descriptive names."

Jul 1, 1947

By O. C. Blade

"INTRODUCTION This report on the properties of motor fuels sold through service stations in the United States is a continuation of a series of reports made in accordance with a cooperative agreement between the Coordinating Fuel Research (CFR) Committee of the Coordinating Research Council (CRC) 3/ and the Bureau of Mines of the United States Department of the Interior. The first of these reports presented data on motor gasolines sold during the winter of 1935-36. 4/ Further reports were issued describing motor gasolines sold during the succeeding summers and winters to and including the summer of 1941. 5/ No reports were made on motor gasolines Bold during the winter of 1941-42 and during the summer of 1942. However, starting with the winter of 1942-43, the semiannual reports were resumed. 6/The present report presents analytical data for 1,499 samples, representing the products of approximately 105 companies. As in previous surveys, the companies covered by the survey include both large and small suppliers. Conforming to former reports, the data cover three groups of samples - regular-price, premium price, and third-grade gasolines.As the number of analyses submitted for samples of third-grade gaso¬line are not considered adequate to represent this type of motor fuel, data for these analyses have not been averaged, but the individual items are tabulated. The number of samples, items and brands comprising each group is as follows; Regular-price, 872 samples, 266 items, and 83 brands; -premium-price, 584 samples, 217 items, and 72 brands; third-grade, 43 samples, 32 items, and 21 brands. The meanings of those terms as used in the surveys are as follows:"

Jun 1, 1945

By R. B. Ladoo

"Present Situation:At the beginning of 1920 a general feeling of optimism was noted in many talc-producing districts. The industry seems to have recovered from the temporary depression of the first half of 1919 and many mills are running at capacity production with their entire output for 1920 contracted for. The imports of talc for 1919 were only slightly larger than in 1918 by weight and probably no more by value. Thus foreign competition has not begun to be seriously felt. Several new companies in this country have been organized, some to operate new deposits and others to continue the work done by others.An interesting phase of the present situation is the possibility of increased use of talc in paint. There is a shortage of barium sulfate used as a paint filler. Since, for some uses, talc is considered second only to BaSo4 as a filler for paint, it is possible that part of the shortage could be relieved by an increased use of talc.A series of physical tests upon all pigment materials used in the manufacture of paints is being conducted for the Paint Manufacturers Association of the United States. It is important that all types of talc be represented in these tests. Producers of finely ground talc, 200 mesh and finer, are urged to submit samples of at least two pounds each of these grades that are available to paint makers with trade name and quality data, to the Institute of Industrial Research, 19th & B Streets, N. W., Washington, D. C., where the tests are being conducted."

Jan 1, 1920

As fulfillment of the requirements of Contract H0387019 for the United States Department of the Interior, Bureau of Mines, a complete field kit, for performing on-site determinations of individual employee Time Weighted Average (TWA) exposures to nitrogen dioxide (NO2) and nitric oxide (NO), has been developed by MDA Scientific, Inc. This report provides background information and experimental data validating the use of this kit with confidence to ? 10 percent accuracy.

Jan 1, 1981

By Joseph Blake Smith

Coal resource data from published sources and company files were used by the Bureau of Mines to determine the location and extent of strippable coal reserves in Wyoming. Total strippable reserves of 23 billion tons were estimated in seven major coal areas. Seven large strip mining operations were active in 1969, and their production totaled 45 million tons of coal. Cutoffs used to define strippable reserves were (1) minimum coalbed thicknesses of 5 feet; (2) overburden-to-coal ratios of less than 10 cubic yards of over- burden per ton of coal; and (3) total overburden thicknesses of less than 120 feet, except where reserves occur in multiple beds or a single thick bed. Tertiary rocks along margins of the Powder River basin contain most of the strippable coal reserves in Wyoming. The Wyodak beds, ranging in combined thickness from 30 to 1.30 feet, crop out on the east flank of the basin and contain an estimated 19 billion tons of strippable subbituminous C-rank coals under less than 200 feet of overburden. Partings between these beds total less than 60 feet. The 100- to 200-foot-thick. Healy bed on the western flank of the basin and the 35-foot-thick School and 20-foot-thick Badger beds on the south also contain large strippable reserves. Elsewhere in Wyoming, strippable reserves. Elsewhere in Wyoming, strippable deposits are subbituminous coal of Late Cretaceous and Tertiary ages, mostly in the Hanna and Great Divide basins in the south-central portion of the State and in the Kemmerer-Hamms Fork region in the southwestern corner.

Jan 1, 1972

By Martin J. Gavin

The results of investigations of the oil-shale resources of the United States were first published by the United States Geological Survey in 1915.1 Other reports 2 have followed. These reports, investigations by private individuals and corporations, and the beginning of the development of an oil-shale industry in this country have aroused considerable interest in the possibilities of these shales as a commercial source of hydrocarbon oils. The Bu- . reau of Mines bas appreciated these possibilities, and since 1916 one or more of its engineers have given all or part of their time to investigations relating to the treatment of oil shales. A short pamphlet a containing general information on the possibilities of oil shale in this country, particularly the shales of the Rocky Mountain district, has already been published. This pamphlet gives methods for assaying the shales of oil and ammonia and contains a bibliography for the use of those desiring to search the literature.

Jan 1, 1924

By B. H. Caudle, A. D. PUCKETT

This paper summarizes precent knowledge of the ignition qualities of pure hydrocarbons likely to be present in modern Diesel engine fuels, as shown by an extensive search of the technical literature. The report also discusses the possible significance of cetane number and hydrocarbon struc- ture. Cetane or cetene numbers, and other physical properties, are tabu- lated for about 100 hydrocarbons, and a bibliography is appended. In recent years the Diesel engine has enjoyed increasing popularity due to its dependability, inherent characteristics of fuel economy, and the fact that it operates on a fuel that hitherto has been available in comparatively large quantities at a low price. These qualities have en- abled the compression-ignition engine to compete very favorably with other types of prime movers in many fields and have led to predictions of fur- ther rapid expansion in the application of Diesel power. In a survey of the field of all petroleum fuels for combustion engines, Holaday et al (9) have predicted that by 1948 railroads will be using 10 times as much Diesel fuel as was used in 1939 and that over-all consumption will have doubled that of 1939. Other estimates of the yearly demand for Diesel fuels five years hence vary from 2,6 to 5 times the amount used in 1944. Into this picture has come the question of whether the greatly in- creased production to meet this estimated demand is compatible with the maintenance and possible improvement in quality of fuels necessary to satisfy future engines. Unfortunately perhaps for the Diesel engine, factors other than those of simple arithmetical multiplication must be considered. For example, the consumption of oil in central heating plants doubled from 1935 to 1943, and a further increase of 57 percent of the 1943 demand is expected by 1950. Jet propulsion has been developed to the stage where it is entirely practical for military aircraft. Catalytic cracking plants, many of which were constructed to meet the war- time accelerated demand for high-octane gasoline, are taking their place in the refining industry. All these developments, as well as the Diesel engine, require material of approximately the same boiling range. Virgin gas oils make excellent burner fuels, perform most satisfactorily in the gas-turbine units for aircraft according to present information, and are at a premium as catalytic cracking stock.

Jul 1, 1948

By Arel B. McMahan

The U.S. Bureau of Mines investigated mines, prospects, and mineralized areas in the Owlshead Mountains Wilderness Study Area (WSA) in 1982. Within the WSA, subeconomic manganese, iron, zinc, and lead resources were identified at two mines; sample analyses indicate five other mines and prospects may have gold, silver, iron, manganese, and copper resources. Three mines examined adjacent to the WSA have identified manganese and iron resources; and sample analyses indicate manganese, iron, and gypsum resources may exist at two prospects. Greatest likelihood for future identification of mineral reserves is for manganese at the Black Magic Mine in the southeast part of the WSA. The southern half of the WSA contains nearly all identified mineral resources, and properties at which sample analyses indicate additional resources. The most significant are manganese and iron resources at the Black Magic Mine in the southeastern part of the WSA; and the Ellie, New Deal, and Owl Hole Mines adjacent to that part of the area. Manganese and iron minerals filled fractures and replaced limestone in brecciated and faulted contacts with intrusive granitic rocks. In the southwest corner of the WSA, sample analyses indicate four prospects may have gold and silver resources. These precious metals are in gouge zones along contacts where diorite has intruded volcanic rocks. A small identified resource at the Kennedy Boys Lead Mine in the western part of the WSA consists of quartz veins with zinc and lead minerals along a brecciated contact between granite and limestone roof pendants.

Jan 1, 1985

By Laurence A. Dahners

As part of the strategic minerals program, the Bureau of Mines conducted a diamond-drilling project on three barite properties in eastern Tennessee and western North Carolina during the summer and fall of 1944. These properties, the Moccasin Gap prospect and the Krebs property in Cocke County, Tenn., and the Sandy Bottom mine of the Stackhouse group in Madison County, N. C. (fig. 1), are known to have produced some barite. The Bureau of' Mines project was planned to prospect for extensions of the ore bodies. A total of 3,169 feet of diamond drilling was done in 15 holes on the three properties. Tabulations of sample analyses and drill-hole logs are presented in this report. Two other mines of interest in the area are the McCoy and the Williams in Cocke County, Tenn. The Williams adjoins the Krebs. No drilling was done by the bureau in either of these properties.

Jan 1, 1949

By Perry D. Teitelbaum

In two earlier studies the Federal Bureau of Mines undertook to explore comprehensively the dimensions of the Nation's energy balance. The first of these studies, published in 1950 as Bureau of Mines Information Circular 7582, by Harold J, Barnett, was primarily concerned with projections of future domestic energy requirements and supplies, because these related to projected growth in major fuel-consuming sectors of the economy, changing rates of energy-use efficiency, and interfuel substitution patterns. But, to provide the essential background for these projections, it was first necessary to assemble and examine in some detail the quantitative information on the size and shape of the current United States fuel economy. Among other things, Barnett's path-breaking study indicated the need to consider energy as an entity, particularly for public and private policy makers, industry and commodity analysts, economists, and others concerned with long range questions of domestic and international energy supply and demand. The study also spotlighted a gap in the fabric of current economic intelligence; no comprehensive collation and reconcilation in any single report of available published statistical information covering the origin -a disposition of all energy materials existed. In response to this latter need, the Bureau of Mines prepared the second of the two studies referred t3 above. This was published in 1951 as Report of Investigations 4805, by W, H, Lyon and D, S. Colby, and it consisted of statistical information on the production and use of each of the various fuels and electric energy in the United States for 1929, 1939, and 1947; all were presented in tabular form and on a uniform basis. The three years selected were chosen largely on the basis of data availability.

Jan 1, 1961

By Steven J. Schatzel

Prior research has suggested that the source of respirable silica dust in underground coal mines is typically the immediate top or bottom lithology adjacent to the mined seam, not mineral matter bound within the mined coal bed. Geochemical analyses were applied in an effort to identify the specific source rock of respirable quartz dust in coal mines. The analyses also demonstrate the compositional changes that take place in the generation of the respirable dust fraction from parent rock material. All six mine sites were mining coal with relatively low mineral matter content, although two mines were operating in the Fire Clay coal bed which contains a persistent tonstein. Interpretations of Ca, Mg, Mn, Na, and K concentrations strongly suggest that the top strata above the mined seam is the primary source of mineral dust produced during mining. One site indicates a mixed or bottom source, possibly due to site specific conditions. Respirable dust compositional analyses suggest a direct relationship between the quantity of mineral Si and the quantity of quartz Si. A similar relationship was not found in either the top or bottom rocks adjacent to the mined seam. An apparent loss of elemental Al was noted in the respirable dust fraction when compared to potential parent rock sources. Elemental Al is present in top and bottom rock strata within illite, kaolinite, feldspar, and chlorite. A possible explanation for loss of Al in the respirable dust samples is the removal of clays and possibly chlorite minerals. It is expected that removal of this portion of the Al bearing mineral matter occurs during rock abrasion and dust transport prior to dust capture on the samplers.

Jan 1, 2009

By W. W. Adams, T. D. Lawrence

"The National Safety Competition of 1938, the fourteenth of its kind conducted by the Bureau of Mines in which bronze trophies known as Sentinels of Safety are awarded to winning companies, has just been completed and the results are presented here.With 345 mines and quarries competing, more than in any previous year except 1931, the contest revealed low accident rates at many of the enrolled plants and, which is even more remarkable, it revealed 113 mines and quarries at which no lost-time accidents occurred during the contest year.The Sentinels of Safety trophies, provided by The Explosives Engineer magazine, were awarded to four underground mines, one open-pit mine, and one quarry. Each employee of the winning plant was awarded a Certificate of Honor by the Bureau of Mines in recognition of the employee's part in helping his company to win the trophy. In addition to the award of trophies, a Certificate of Honorable Mention was awarded to each of the mines and quarries in second, third, fourth, and fifth places in their respective contest groups and also to each mine and quarry that worked 30,000 or more man-hours without a lost-time accident. Ninety-two such certificates were awarded for 1938. Twenty-three other mines and quarries also operated without an accident but worked less than 30,000 man-hours, the minimum required by the contest rules for award of Certificates of Honorable Mention.Previous to 1938, five trophies were awarded annually in the National Safety Competition. For the 1938 contest a sixth trophy was provided by The Explosives Engineer so that open-pit mines and quarries, two classes of operations that previously had been included in one group in the competition, might have separate awards."

Aug 1, 1939

By Manuel Gomez

This report presents low-temperature tar data from studies by the Bureau of Mines of tars produced in an externally heated (entrained state) pilot-plant-scale retort. Analytical data covering 20 low-temperature tars, derived from the. carbonization of various ranks of foreign and domestic coals, are tabulated. The character of the tar is discussed in relationship to carbonizing conditions and the rank of coal. It is seen that in carbonization techniques that employ entrainment or fluidization of the coal particle, carbonization conditions are secondary to coal rank with respect to tar-oil yields and composition. The influence of distillation conditions on recoverable yields of tar products is presented. The probable yield of commercially important chemical products, based on a ton of pure (moisture- and ash-free) coal, are predicted. INTRODUCTION Low-temperature tars produced by entrainment or fluidized carbonization techniques that employ internally heated reactors represent the most nearly primary tart produced by industrial processes. In brief, such a process involves the application of a heat gradient to the coal particle "boiling" or suspended in a turbulent state in the reactor chamber. Conditions are observed so that the coal particle remains suspended within the reaction zone by a gas stream for a time interval commensurate with maximum tar-oil yield. The heat necessary for the carbonization reaction may be obtained entirely from the hot (preheated) gas stream, or it may be derived partly from the combustion of the volatile products and char by the transport gases, usually air. The volatile material moves out of the carbonizing zone at a rate that approaches the velocity of the transport gas. Carbonizing conditions are ideal when a minimum particle residence time is obtained within the reactor at a given temperature and a maximum yield of condensable volatile matter is released. In industrial practice this objective is a compromise.

Jan 1, 1957

By H. C. Fuller

A method was devised and developed by the Bureau of Mines for decomposing manganese sulfate at significantly lower temperature than that required by the conventional procedure of using heat alone. This technique, called the partial reduction method, effected decomposition at 700° to 800° C, as compared to 900° 1,000° C normally required. The process consisted of heating, in the absence of oxygen, a mixture of manganese sulfate and a controlled quantity of a reducing agent. The suitability of commercial-type equipment was tested in laboratory-size models of an externally heated rotary kiln, a r bbled muffle-hearth furnace, and a fluidized-bed reactor. The rabbled-hearth furnace gave the best results with the least operating difficulty produced a gas containing more than 80 percent SC and eliminated 96 percent of the sulfur when coal was used as the reductant. Sintering of the powdery decomposition product produced an agglomerate containing, in percent, 63.6 Mn and 0.4 S.

Jan 1, 1966

By Charles W. Huggins

To determine the nahcolite and dawsonite content in oil shales, the Bureau of Mines compared X-ray diffraction, infrared spectroscopy, thermal methods, and a previously published method by Smith and Young based on the selective solubility of sodium compounds. The Smith and Young method and a new method based on the weight of carbon dioxide produced by thermal decomposition are recommended for determining nahcolite. X-ray diffraction and the Smith and Young method are recommended for determining dawsonite. X-ray diffraction, infrared spectroscopy, and differential thermal analysis were useful for identifying other minerals in the samples.

Jan 1, 1973

Control shearer-generated airborne respirable dust on longwall mining sections. Approach Previous Bureau studies have shown that using high-pressure water can have a significant impact on the amount of airborne dust released into the face airflow while cleaning and controlling the airflow in the immediate cutting zone. The basic concept to improve the drum water spray system was to utilize high-pressure (1,200 psi) inward-facing drum sprays to improve the dust knockdown efficiency of the spray system and confine the dust to the face area. This system would minimize the exposure of the shearer operator through dust avoidance and decrease face dust levels by suppressing the amount of respirable dust that becomes airborne. System Design In-mine tests were designed to provide information that would permit evaluation of the operation with different spray orientations and water spray pressures. This was achieved by comparison with a conventional baseline wet-cutting system consisting of 26 low-pressure bit sprays, located on the hit blocks to provide pick-point flushing. Total drum water flow was 60 gpm and was maintained continuously throughout all tests. The high-pressure inward-facing drum water spray system consisted of sprays located in each bit block, oriented 15° and 30° toward the face. The inward-facing water spray system was operated at either 800 or 1,200 psi.

Jan 1, 1989