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In 2004, a total of 4,401 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA). Stone mines comprised 30.4% of all mining operations.

Sep 1, 2007

By F. Chen, L. J. Gaydos, L. M. Demers, D. C. Kuhn, S. C. Sun

"In this report, we demonstrate that NF-KB, a ubiquitous transcription factor, plays an essential role in silica-induced inflammatory mediator production in the mouse macrophage cell line RAW 264.7. Compared to the effect of lipopolysaccharide (LPS), silica mediated a stronger activation of NF-KB p50/p50 homodimer at early phase of poststimulation. Furthermore, activation of NF-xB by silica and LPS appears to be mediated by different signal transduction pathways. Both silica and LPS increased mRNA expression in these cells for cyclooxygenase II, inducible nitric oxide synthase, tumor necrosis factor-a and interleukin- I a. This expression was attenuated along with the inhibition of NF-KB activation. It is well documented that exposure of alveolar macrophages to silica can initiate excessive production of inflammatory mediators and cytokines from several early response genes (1-3). At the DNA level, a common structural characteristic of these genes is the presence of one to five NF-lCB binding sequences (KB) in the 5'-flanking region (4-6). In resting cells, NF-KB is retained in the cytoplasm in an inactive form by binding to inhibitory protein known as hcBcx, hcB~. p 105 (precursor of p50) and p 100 (precursor of p52) (7-9). Upon cellular stimulation, these inhibitory proteins are proteolytically degraded or processed by certain proteases, which allows the liberated NF-KB to translocate into the nucleus as an activated form to initiate or regulate early response gene transcription by binding to its consensus element (GGGRNNYYCC)(7).In this report, we demonstrate that silica can efficiently induce NF-lCB activation in RAW 264.7 cells, and that silica displays different characteristic from LPS in the activation of NF-KB, both with respect to NF-KB subtype composition and the signal transduction pathway that leads to the activation of NF-KB. In addition, abrogation of NF-KB activation by inhibiting the protease can dramatically reduce the mRNA expression of cyclooxygenase II, inducible nitric oxide synthase, tumor necrosis factor-ex (TNF-o.) and interleukin-lex (IL-lex). These findings strongly suggest that NF-KB plays an essential role in silica-induced inflammatory mediator production in the monocyte/ macrophage cells."

Dec 1, 1996

By R. Hogg, S. Chander

"The distribution of the wettability of coals of different rank was determined by measurements of contact angles for individual particles. The contact angle was estimated from the equilibrium partitioning of a particle at the water/air interface. Using this technique contact angles were determined for a larger number of particles from a given sample and a frequency distribution of contact angle was obtained. The contact angle distribution was broad for all the coals tested with included an anthracite, a hvA bituminous and a sub-bituminous coal. In comparison, spherical particles of polymethylmethacrylaie gave a much narrower distribution. The distribution for irregular polyethylene particles was somewhat broader than that for the polymethylmethacrylate spheres but broader than that for the polymethylmethacrylate spheres but considerably narrower than that for coal. The broader wetting distribution for coal was attributed to differences in surface chemical properties.INTRODUCTIONA knowledge of the wetting properties of coals is very useful in coal cleaning by flotation and other processes in which separations are based on differential surface properties. The various methods available for measuring wetting characteristics include: contact angle, 1-2 time, time, 3-5 bubble attachment, 6 film flotation,7 displacement pressure, 8-9 penetration rate, 10-11 bubble pick-up, 12 induction time, 13 imbibition time, 14 and calorimetry. 15-16 Of all these methods, however, the measure¬ment of contact angle by the sessile drop and captive bubble techniques have been most widely used. Brady and Gauger"" demonstrated through the use of the contact angle method that the natural hydrophobicity of coal varied greatly from sample to sample. Subsequent experiments showed that this difference correlated well with rank, the larger contact angles generally being associated with the higher rank coals. 18-19 More recent studies by Aplan and co-workers' show that the wettability of various ranks of coals as determined by sessile drop and captive bubble methods is a more complex function of rank. The hydrophobicity of coal usually increases with rank up to about 80% fixed carbon (dmmf) and then decreases."

Mar 1, 1992

A preliminary research and development program dated April 25, 1974, was prepared for Development Engineering, Inc. (DEI) for laboratory, field and other engineering studies on the disposal of retorted oil shale. This program was revised and published as a final document dated December 17, 1974. The document included discussions on the peculiarities of retorted shale materials to be investigated and discussions of the various laboratory and field tests which would need to be conducted to define their physical and chemical properties. The proposed research and development program was divided into eight work phases as follows: I Program Development. II Exploratory Laboratory Tests on Old U.S.B.M. Retorted Shale. III Laboratory Tests on Pilot Plant Retorted Shales. IV Laboratory Tests on Retorted Shales from the Semi-Works Plant.

Jan 1, 1976

By Lloyd A. Morley

This report abstracts project work performed under USBM Grant GO155003 during the period 4 November 1975 to 3 November 1976. The research was funded, as a continuance of previous support from USBM Grants GO133077 and G0155003, to gain further knowledge in mine electrical system safety. Five reports have been separately produced, all under the grant title, "Coal Mine Electrical System Evaluation," and are as follows: 1. Volume I - Continuous Monitoring, 2. Volume II - Transient Analysis, 3. Volume III - Shielded Cables, 4. Volume IV - Computer Modeling, and 5. Volume V - Battery and Battery-charging Safety. Abstracts of these comprise the balance of this document with one exception. The task ?d-c offsett currents," does not fall under the scope of the other report volumes and, further, the material to be presented does not justify a separate report. Hence, this subject concludes the Executive Summary.

Jan 1, 1977

By W. R. K. Wu

Studies are reported on the structure of coal and coke with the graphical , statistical densimetric method based on the relation between the molecular volume per carbon atom ( M / C ) and the atomic hydrogen - carbon ratio ( H / C ) . Previous work , mostly from chemical and physical investigations , is critically reviewed . Difficulties in evaluating the ring increment are demonstrated for coal and coke for the statistical densimetric method based on the additivity of atomic volumes of constituent elements . A new diagram is presented for the graphical method . Methods are introduced for correcting M /C and H/C for the presence of minor constituents in coal and coke . With the graphical method , the fractions of aromatic carbon atoms in the total carbon atoms are estimated for a coal , a resin , and 5 petrographic components ; the types of condensed structure in the fundamental units of molecules are discussed for these substances , 28 coals , and 6 " average " cokes at 500 ° to 1,000 ° C. It is also shown that the number of rings in the fundamental units of coal generally increases with increasing rank and that of coke , with increasing carbonization temperature .

Jul 1, 1960

By T. L. Iapalucci

To determine the behavior of chlorine in coal combustion, the Bureau of Mines burned 10 chlorine-containing coals, high-, medium-, and low-volatile, in a laboratory-scale pulverized-coal combustor. At carbon-combustion efficiencies of 94 to 98 percent, 1.6 to 7.1 percent of the chlorine or an average of 4 percent of the chlorine in the coal was retained in the ash; the balance, predominantly hydrogen chloride, was evolved in the combustion gas. Sulfur retention in the ash ranged from 2.3 to 10.7 percent or an average of 6.3 percent, Addition of alkali and alkaline earth carbonates to a medium-volatile coal containing 0.27 percent chlorine by preferentially reacting with the chlorine increased the Cl/S atom ratio in the ash, Lithium carbonate addition at 0.43 percent and K2C03 at 1.59 percent increased the C1/S ratio in the ash from 0.2 to 0.6.

Jan 1, 1969

By Arnold B. Hubbard

This report describes a method of concentrating the insoluble organic material (kerogen) in a rich Colorado oil shale without any apparent alteration of its original chemical form. The method involved treating finely pulverized shale with dilute acetic acid at room temperature to remove the carbonates, which act as a cementing agent for the shale, and cause the shale particles to partly disintegrate into the organic and inorganic components. The acid-treated shale then was centrifuged in different liquid mediums ranging from 1.4 to 1.15 gravity to effect a mechanical separation. From a Colorado oil shale containing 48.0 percent ash, kerogen concentrates containing 43.3 to 8.7 percent ash were obtained. The carbon:hydrogen ratios of the kerogen in the original shale and the different concentrates were essentially the same. The oil:kerogen ratios calculated from Fischer assays of the above samples were essentially the same, regardless of the organic or inorganic contents. This was also true of the assay water:kerogen ratios of the same samples. These data indicate that no significant change occurred in the kerogen during the concentration process.

Jan 1, 1952

By K. E. Stanfield

The Bureau of Mines oil-shale program, initiated in April 1944, is concerned with the future utilization of oil shale in the United States as a source of liquid fuel. One phase of this program is the accumulation of information on the location, extent, and richness of oil-shale deposits that may be suitable for processing to oil and related products. A previous publication5/ presented, by means of logs, the oil yields of sections of the largest known oil-shale deposit in this country -the shales of the Green River formation occurring in adjoining portions of the states of Colorado, Utah, and Wyoming. This present supplementary report presents the oil yields of cores from 48 holes drilled during 1952 to 1954 in the Green River formation of Colorado, which is distributed over an area of more than 1,000 square miles. The oil yields of the 48 oil-shale sections, involving the assay of 9,651 samples, representing 22,451 feet of core, are presented by means of logs. In addition, the oil yields of samples comprising the maximum sections of 15 gallon-per-ton shale are tabulated for these cores and for the 28 cores from Colorado which were logged in the previous report.

Jan 1, 1957

By W. P. Diamond

Coalbeds exhibit a directional permeability, with the maximum permeability oriented parallel to the face cleat. Thus, the most efficient pattern of vertical degasification holes for a coalbed is dependent upon cleat orientation. Surface joints, infrared photolinears, and Ronchi grating photolinears were investigated as potential estimators of subsurface cleat orientation. Cleat orientations were measured in 18 mines, in the Pittsburgh coalbed in southwestern Pennsylvania and northern West Virginia to be used as a standard against which prediction techniques would be evaluated. Two cleat systems with a strong geographic segregation were measured in the study area: N 670 W -N 280 E (950 separation) for the north, and N 76° W -N 17° E (930 separation) for the south. Directional data obtained from the three techniques investigated yielded satisfactory regional predictions of cleat orientation. Analysis of surface joints was the only technique considered sufficiently reliable on a local basis. Prediction of cleat orientation is based on the pairing of the principal directional sets into all reasonable combinations of fundamental systems. The system or systems composed of the most dominant sets nearest to 90° separation are likely to be a reliable prediction of cleat orientation. The most dominant set of the system selected is likely to be the face cleat.

Jan 1, 1976

By J. Roger Loebenstein

This report presents a U.S. Bureau of Mines study of the flow of arsenic-containing materials in the United States, based on the best data available in 1991, includes a consideration of arsenic as a byproduct of the processing of nonferrous metals, the fate of arsenic in manufacturing wastes, the quantity of arsenic used in products, tile fate of arsenic in dissipative uses, and the useful life of discarded products. Where possible, estimates are given of the amounts of arsenic lost from the materials flow. Arsenic byproduct of mining nonferrous metals. Historically, most U.S. production has been from the states of Montana, Washington, and Utah. The smelters in these states are believed to be the areas of the country where arsenic is most concentrated in the soil, tailings ponds, and waste dumps. Since the closure of the last domestic producer of arsenic in 1985, all arsenic has been derived from imported sources. Historically, arsenic was important in agricultural applications as an insecticide, herbicide, and cotton desiccant. As the environmental movement gained momentum and the toxicity of arsenic became better understood, most of the agricultural uses for arsenic were banned. Beginning about 1975, the use of arsenic as a wood preservative began to grow. After 1980, wood preservative uses became more important than agricultural applications. By 1990, 70% of the arsenic consumed in the United States was used by the wood preservative industry and 20% by the agricultural industry. The major source of domestic arsenic emissions in 1989 was from the U.S. copper processing indus¬try. About 7,800 mt/yr of arsenic was discarded in leach dumps, tailings, and slag. Another 800 mt/yr was liberated to the atmosphere and 1/100 mt/yr was exported in copper concentrates. On the consumption side, 9,200 mt/yr was lost, mostly from dissipative agricultural uses and the disposal of obsolete arsenical products.

Jan 1, 1994

By Philip Thompson

A part of the Bureau of Mines mission is to help improve the Nation's mineral posture by providing the technology for utilizing low-grade ores. In this regard, laboratory testing by the Bureau of Mines has shown that the removal of insoluble slimes using selective flocculation and flotation is a viable method for treating low-grade potash ores that have a high content of water-insoluble impurities. Results indicated that over 82 percent of the insoluble slimes could be removed from sylvinite ore containing 5 percent water insolubles and 13 percent K20 by using nonionic or cationic polyacrylamide flocculants and cationic, anionic, and/or nonionic collectors. Subsequent potash flotation recovered 87 percent of the potash in rougher concentrates containing 57 percent K2O. Sizing and cleaner flotation of the rougher concentrates upgraded the products to 60 percent K2O. Filtration of the water-leached insoluble-slimes flotation concentrates on a bed consisting of leached insoluble-slimes concentrate mixed with potash flotation tailings recovered 80 percent of the brine. Filtration rates using the mixed bed were nine times faster than filtration rates obtained when the insoluble-slimes flotation concentrates were filtered separately.

Jan 1, 1979

By Ronald A. Munson

Samples of the naturally occurring zeolites phillipsite, clinoptilolite, erionite, and chabazite have been surveyed for their gas adsorption, ion exchange, and other characteristics. Chabazite and erionite, which are generally more stable, also have higher methane adsorption capacities than do the other natural zeolites. Both natural erionite and natural chabazite are classified as small-port zeolites on the basis of their inability to adsorb chlorotrifluoromethane. In the range of 8 to 100 mesh, the adsorptive capac-ity of natural zeolites is improved only slightly by a decrease in particle size. The capacity of natural clinoptilolite to adsorb methane is increased by cation replacement by the hydrogen ion and decreased by exchange with calcium ion. Natural phillipsite, which is easily decomposed by heat, adsorbed methane to a limited extent.

Jan 1, 1973

By D. Harrington

For several years, or from about 1932 to 1935, inclusive, the coal industry of the United States had an excellent record as to coal-mine explosions. In 1937 and in 1938 to date there has been a definite increase in the number of explosions attended by considerable loss of life and property damage. In most of these explosions one important underlying and contributing cause has been lack of sufficient (or at least efficient) ventilation to properly dilute and remove explosive gas from the mine. This increase in explosions indicates that. the lesson taught through bitter experience, many times in the not far-distant past, of the need for good ventilation is frequently being overlooked, partly because the relatively good experience of the industry in the past several years has made many mining people forgetful. Moreover mining practices are rapidly changing, and in some instances the changes are being made with little if any regard for safety. It appears, therefore, that a review of some ventilation principles and practices should be of value in preventing further disasters; this paper has been prepared with that object in mind. In coal mining the need for thorough ventilation of all underground working places is recognized by both mining practice and law; such ventilation is generally obtained by the use of fans that circulate a quantity of air much in excess of the quantity of coal produced, by weight as well as by volume. For example, in a relatively small mine producing 1,000 tons of coal per day and circulating 100,000 cubic feet of air, which is by no means abnormal, 2,000,000 pounds of coal and approximately 10,900,000 pounds of air would be moved out of the mine every 24 hours. Because of the need for adequate dilution and removal of methane issuing or likely to issue from mine strata and for removal of the carbon dioxide formed by coal and timber oxidation up-to-date coal mines usually provide an air volume which if adequately coursed not only removes these gases but also the gaseous products of the detonation of explosives (which may include carbon monoxide, hydrogen sulphide, nitrogen oxides, carbon dioxide, and nitrogen) and the carbon

Jan 1, 1938

By W. B. Berwald, T. W. Johnson

"The United States Bureau of Mines, in cooperation with the Natural Gas Department of the American Gas Association, has been studying actively for the past several years the flow of natural as through high-pressure pipe lines. 4 This report deals with that part of the study involving the design of pipe-line systems consisting of lines laid parallel to each other. The lines are referred to as the original line and the parallel line. The paralleling lire may or may not extend the entire length &f the original line; however, the parallel line is connected at its two ends to the original line.As a result of the large expansion of the natural-gas industry almost all markets within economic distance, from the developed as fields have at least one pipe line supplying them with natural gas. Small increases in the consumers' demand for natural-gas can be met usually by increasing operating pressures, but any marked increase in demand necessitates paralleling sections of the existing systems. It is believed that to a large extent future expansion in the natural—gas industry will consist of paralleling the present lines. The several formulas given in this report have been developed to aid in the design of such systems. Curves and tables were prepared from these formulas to simplify the calculations materially and to facilitate determination of the sizes of pine to be used in paralleling various diameter lines to give the most economical design. The formulas are presented without detailed derivations, as a complete report on the flow of natural gas through pipe lines is being prepared which will contain the derivations of these formulas. Examples included here show the detail of application of the several formulas to problems of design of parallel lines."

Jun 1, 1934

By T. F. Mitchell, Walter J. Long

"SUMMARYThis report is one of a series giving results of laboratory and pilot-plant investigations of the concentration of western manganese ores begun in December 1940. Data given summarize results of laboratory investigation of three samples of complex oxide manganese ores from the Madeline property, Lake View, and Victory claims, Clallam County (Olympic Peninsula), Wash. The samples represented an extremely intimate and complex association of manga¬nese oxide minerals with silica and iron.Owing to the complex nature of the ores, no effective concentration by ore-dressing methods was possible. No high-grade manganese concentrates were produced and the highest recovery at minimum accountable grade was only 55 percent on one of the ores tested.Since the Clallem County ores did not respond to ore-dressing methods, leaching processes were investigated, results of which are to be published in a separate report.INTRODUCTIONOre-beneficiation tests were conducted on three samples of manganese oxide ere from the Madeline, Lakeview, and Victory claims, Clallam County, Wash. The ores are extremely complex because of the unusually small size of manganese mineral particles, their mode of occurrence, and relationship to the gangue. None of the three ores was amenable to the production of high-grade manganese products by ore-dressing methods."

Dec 1, 1945

By Jr. Kauffman

The data contained in this report were obtained incidental to the Bureau of Mine's investigation of the lime-soda sinter process as applied to the recovery of alumina from siliceous bauxite, kaolin, and other high aluminous materials. The Bureau of Mines was charged by Congress to investigate processes for the production of aluminum from domestic low-grade ores. The Eastern Experiment Station at College Park, Md., conducted laboratory and pilot-plant investigations of the recover-y of alumina by the lime-soda sinter process. Reports by the College Park staff covering the recovery of alumina from these sources have been published. The lime-soda sinter process involves the sintering of the finely ground siliceous bauxite or clay with limestone and soda ash in a rotary kiln. During the sintering the alumina supposedly reacts with the soda ash to form soluble sodium aluminate and the silica combines with the lime to form the insoluble orthosilicate. In the early stages of the investigation it was considered desirable to know the temperatures at which the phase changes occurred during the sintering operation. The total time involved in the passage of any given portion of the charge through the kiln was 28 minutes. The exposure time of the charge to temperatures above 600° C. (decomposition temperature of kaolinite) was, roughly, half the total. The exposure to the full temperature of the kiln, 1,100° C was only 3 minutes. (Subsequently, the maximum kiln temperature and retention time were increased.)

Jan 1, 1949

By A. R. T. Denues

"INTRODUCTION The Explosives Division of the Bureau of Mines, United States Department of the Interior, is investigating cushioned blasting at the Explosives Testing Station, Bruceton, Pa. The general interests of this investigation are practical and relate particularly to safety. The immediate concern is an application of cushioned blasting in coal mining.In cushioned blasting, various means are employed to reduce the intensity of the application of energy in an explosive action in a borehole. The primary object is to increase the efficiency of the use of explosives. Cushioned blasting is designed to save the energy usually lost in excessive shattering and in this way to effect economies and to produce increased proportions of desirable lump coal. That this saving should lead to greater efficiency is indicated by an analogy with the theory and experience of size-redaction by crushing or grinding from which it is known that a large proportion of the energy consumed is expended in producing the smaller sizes (26),3/. Aside from these considerations, increasing the yield of lump coal is important in practice because larger sizes of coal usually sell at higher prices. Some statistics published in England in 1934 (63) illustrate the economic origin of the interest in increasing yields of lump coal; these indicate for three sizes of coal that as the size decreases the value decreases in the approximate series 3:1.5:1, thus:"

May 1, 1940

By William J. Campbell

The Federal Bureau of Mines provided five test materials--amosite, short-and long-fiber chrysotile, crocidolite, and nonfibrous tremo1ite--to the National Institute of Environmental Health Sciences (NIEHS) for studies on the biological effects of orally ingested asbestos-related materials. An inter-agency agreement between the Bureau and NIEHS made possible this program to characterize these test materials. The Bureau in turn received support through contracts with the Ontario Research Foundation for the milling of amosite and crocidolite, and with the University of Maryland for microscopic measurements. The five test materials, which were supplied in quantities of 960 to 1,200 pounds each, were characterized by chemical-instrumental analysis for elemental composition, surface area, density, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, mineralogy, and particle size analyses. Particle size distributions were emphasized because of the current theories relating adverse biological effects to length-width characteristics of durable elongated particles.

Jan 1, 1980

By Lowell Stroud

Since 1929, the Helium Activity of the Bureau of Mines has operated a helium-extraction plant at Amarillo, Tex. The natural gas that supplies this plant is obtained from the Cliffside geologic structure 12 miles to the northwest and over the years, has become known simply as "Cliffside gas," There is need for published data on the low-temperature phase equilibria of helium-bearing natural gases. To date, little information has been published on the equilibrium phase compositions, solution of helium in condensed natural gas, condensation characteristics, or equilibrium vaporization coefficients for methane, nitrogen, and helium in helium-containing systems. A windowed phase equilibrium apparatus (8)6 was used to obtain 105 equilibrium samples, representing 35 experimental conditions of condensed Cliffside gas at pressures of 100, 200, 300, 400, and 500 p.s.i.a. and temperatures from 0° to -270° F. Data on equilibrium vapor-liquid composition for Cliffside gas are presented in both tabular and graphic form and are discussed in detail to show their relationship to certain criteria that must be met to effect an efficient separation of helium from natural gas by means of low-temperature processes. Facts about condensation characteristics and solution of helium in the liquid phases are included, The important relationship of these two factors in decreasing the percentage of total helium lost by solution in the liquid phase is discussed.

Jan 1, 1961