United States Bureau Of Mines Research Articles

Infrared Analysis of Respirable Coal Mine Dust for Quartz: Thirty-Five Years

Abstract The Mine Safety and Health Administration (MSHA) analyzes respirable coal mine dust samples for quartz content using infrared spectrometry. Samples are low-temperature ashed in an oxygen plasma, suspended in isopropanol, and redeposited onto a vinyl/acrylic copolymer filter for analysis using a Fourier transform infrared spectrometer. The on-filter infrared method was developed by the United States Bureau of Mines and collaboratively tested by Stanford Research Institute (SRI) under contract to the National Institute for Occupational Safety and Health and the Bureau of Mines. The results of the collaborative study were published in 1983. Although much work has been performed since then to improve the precision of the method, details of those improvements have not always been published. Standard methods often do not discuss analytical theory and the preliminary steps necessary to achieve precise results. This paper gives a brief background of the changes that have been made in the procedures used for the analysis of respirable coal mine dust samples for quartz and discusses the current procedures used by MSHA to analyze such samples. Factors affecting the analysis such as optimization of the deposit size of the ashed sample, the importance of centering the sample in the infrared beam, baseline selection points, and peak measurement techniques, as well as the quality assurance procedure and the precision of the analysis, are discussed.

Environmentalism and the Disaster Strategy

I. INTRODUCTION Thinking about the third generation of international environmental law means trying to forecast the future. Many assume that this is an impossible task and that the rule prophecy, especially for the is to be strictly observed.(1) But it is an activity which many groups love: economists, political scientists, and social researchers on the one hand; environmentalists and environmental lawyers, on the other. However there is a difference between the two groups. For the expert of the first group, the future is not necessarily worse than the present: it could even be better. On the contrary, environmentalists and environmental lawyers constantly imagine the future ranging from bad to very bad. This attitude is not a new development. It is deeply rooted in environmental thinking. Beginning with the prediction of Malthus in 1798 that starvation in Great Britain was imminent, there has been an endless chain of predictions of catastrophe concerning irreversible environmental damage and unavoidable scarcity of food, minerals, water and other natural resources. A few examples are sufficient. In 1865 Stanley Jevons predicted the end of coal in Great Britain in a few years. In 1914, the United States Bureau of Mines reported that oil reserves would last no more than ten years. According to official reports of the US Department of Interior published in 1939 -- and again in 1951 -- oil reserves would last slightly more than one decade. In 1972 a world famous book, The Limits of Growth, predicted a coming shortage of world reserves of oil, natural gas, silver, tin, uranium, aluminum, copper, lead, zinc and many other resources. All these predictions were completely incorrect.(2) Then in 1973 the World Watch Institute started its yearly forecasts of scarcity of food production. Year-by-year, predictions go on, almost always later proven inaccurate. Since 1961 the world population has doubled. And food demand has increased rapidly: every year there are 90 million more human beings to feed in the developing countries alone. Demand also increases because people in developing countries are wealthier: they have developed a taste for meat; and to fatten livestock it takes a considerable amount of grain.(3) But food production has more than doubled. Although the greater increase of production occurred in developed countries, while the population increases mainly occurred in underdeveloped ones (this makes evident that the problem is not so much of production, but of redistribution of the resources and of protectionism measures adopted and strictly implemented by rich countries against poor ones),(4) the Food and Agriculture Organization (FAO), the International Food Policy Research Institute (IFPI) and the World Resources Institute are persuaded that agriculture can cope with a growing population(5) for many decades to come. A similar history can be traced for pollution. During the Seventies the enemy was nuclear energy; during the Eighties, chemicals and acid rain. Chemicals were considered the principal cause of the increased incidence of cancer. However, recent medical statistics agree that the rate of mortality from cancer not related to smoking has actually declined since 1950.(6) The decline of the forests in Germany and in the U.S., confidently attributed in the past to acid rain and considered irreversible, reverted its trend years ago. FAO reports that forest cover in Europe (excluding the Former Soviet Union) increased by more than four percent between 1980 and 1994 and grew in the first half of the Nineties by three percent; in the same period growth in the United States was two percent.(7) Few today attribute the previous decline to acid rain. With cautious terms, the problem is now described as follows: Over the years, scientists, foresters, and others have watched some forests grow more slowly without knowing why. The trees in these forests do not grow as quickly as usual. …

Empirical measures of wettability in porous media and the relationship between them derived from pore-scale modelling.

The wettability of a crude oil/brine/rock system is of central importance in determining the oil recovery efficiency of water displacement processes in oil reservoirs. Wettability of a rock sample has traditionally been measured using one of two experimental techniques, viz. the United States Bureau of Mines and Amott tests. The former gives the USBM index, IUSBM, and the latter yields the Amott–Harvey index, IAH. As there is no well-established theoretical basis for either test, any relationship between the two indices remains unclear.

Effect of Inerts on Layer Ignition Temperatures of Coal Dust

An experimental study into the hot surface ignition of coal dust layers has been conducted. Two coals were examined: Prince coal from the Cape Breton Development Corporation and Pittsburgh coal from the United States Bureau of Mines. The effect of admixed inerts (dolomite and limestone) on the dust layer ignition temperature has been analyzed using a steady-state thermal explosion model. The analytical procedure used for evaluating the ignition temperature of a dust layer, heated from below and losing heat from its upper surface by convection, is an extension of the thermal explosion model of Thomas (Ref. [8]); namely, that of Thomas and Bowes (Ref. [15]). To commission the hot plate apparatus and validate the model predictions, a series of experiments were undertaken using sodium dithionite. This material is known to exhibit self-heating and there have been previous layer ignition temperature studies with which to compare results. It was demonstrated that an adequate estimate of the critical ignition temperature may be readily obtained by this analytical method. Furthermore, computed values of the critical ignition parameters for layers of coal dust admixed with inerts, accounting for changes in thermal conductivity, were in reasonable agreement with experimentally determined values.

Transient testing of soy methyl ester fuels in an indirect injection, compression ignition engine

AbstractAn evaluation of the exhaust emissions from a compression ignition engine for fuels composed of 100 and 30% methyl esters of soy oil (SME) is described. These fuels were compared with a low‐sulfur, petroleum #2 diesel fuel in a Caterpillar 3304, prechamber, 75 kW diesel engine, operated over heavy‐ and light‐duty transient test cycles developed by the United States Bureau of Mines. More than 60 h of testing was performed on each fuel. The objective was to determine the influence of the fuels upon diesel particulate matter (DPM) and gaseous emissions. The effect of a modern diesel oxidation catalyst (DOC) also was determined in an effort to minimize emissions. Neat SME produced a higher volatile fraction of the DPM, but much less carbon soot fraction, leading to overall DPM reductions of 23 to 30% for the light‐ and heavy‐duty transients. The DOC further reduced the volatile fraction and the total DPM. The SME fuel reduced gaseous emissions of CO by 23% and hydrocarbons by over 30% without increasing NOx. The DOC further reduced CO and hydrocarbon levels. Mutagenicity of the SME exhaust was low. Results indicate that SME fuel, used with a proper DOC, may be a feasible emission reduction technology for underground mines.

ASSESSMENT OF THE APPLICABILITY OF AN ANOXIC LIMESTONE DRAIN FOR A SURFACE MINE IN EAST CENTRAL TENNESSEE

Anoxic limestone drains (ALDs) are a cost-effective technique for adding alkalinity to acid mine drainage. However, the applicability of an ALD is limited to a rather narrow range of mine drainage chemical conditions due to concerns about the armoring of limestone with ferric hydroxide, the plugging of flow paths with aluminum hydroxide, and the limited solubility of calcite. While the armoring and plugging potentials can be assessed with careful water quality analyses, the solubility of limestone in a particular mine water cannot, at this time, be predicted from mine water chemistry. Thus, the danger always exists that the ALD will generate insufficient alkalinity to completely neutralize the acidic water, resulting in either insufficiently treated discharge or a need for additional treatment. In order to remove uncertainty from the design of a 4,000-ton ALD, we conducted limestone incubation tests and pilot-scale ALD tests. Incubation tests were done using a modified version of the {open_quotes}cubitainer{close_quotes} procedure developed by the United States Bureau of Mines. The pilot ALD consisted of 65 tons of limestone. Hydrologic loading experiments were conducted that provided an assessment of the ALD performance under design flow conditions and flow rates four times higher than the design flow. Under design more » flow conditions, the pilot ALD discharged water with alkalinity concentrations similar to that predicted by the cubitainer tests (360 parts per million). With increased flow, concentrations of alkalinity in the pilot ALD effluent decreased, with the water becoming net acidic at a flow rate of 15 gallons per minute. The results of the pilot ALD were used to size a full-scale ALD and model ALD performance under a variety of flow conditions. « less

Solidification and solid-state transformation mechanisms in Si alloyed high-chromium white cast irons

Chromium white cast irons are widely used in environments where severe abrasion resistance is a dominant requirement. To improve the wear resistance of these commercially important irons, the United States Bureau of Mines and CSIRO Australia are studying their solidification and solid-state transformation kinetics. A ternary Fe-Cr-C iron with 17.8 wt pct (pct) Cr and 3.0 pct C was compared with commercially available irons of similar Cr and C contents with Si contents between 1.6 and 2.2 pct. The irons were solidified and cooled at rates of 0.03 and 0.17 K · s-1 to 873 K. Differential thermal analysis (DTA) showed that Si depresses the eutectic reaction temperature and suggests that is has no effect upon the volume of eutectic carbides formed during solidification. Microprobe analysis revealed that austenite dendrites within the Si alloyed irons cooled at 0.03 and 0.17 K·s-1 had C and Cr contents that were lower than those of dendrites within the ternary alloy cooled at the same cooling rate and a Si alloyed iron that was water quenched from the eutectic temperature. These lower values were shown by image analysis to be the result of both solid-state growth (coarsening) of the eutectic carbides and some secondary carbide formation. Hardness measurements in the as-cast condition and after soaking in liquid nitrogen suggest an increase in the martensite start temperature as the Si content was increased. It is concluded that Si’s effect on increasing the size and volume fraction of eutectic carbides and increasing the matrix hardness should lead to improved wear resistance over regular high-chromium white cast irons.

On the nature of eutectic carbides in Cr-Ni white cast irons

The mechanical and tribological properties of white cast irons are strongly dependent on whether they contain M7C3 or M3C carbides (M = Fe, Cr,etc.). In an effort to improve the wear resistance of such materials, the United States Bureau of Mines has studied the effects of adding 0.3 to 2.3 wt pct (throughout) Si to hypoeutectic irons containing approximately 8.5 pct Cr and 6.0 pct Ni. The eutectic carbides formed were identified by electron microprobe analysis, X-ray diffraction, and scanning electron (SEM) and optical microscopies. In addition, differential thermal analysis (DTA) was used to study the process of solidification. At Si contents of 0.3 and 1.2 pct, the eutectic carbides exhibited a duplex structure, consisting of cores of M7C3 surrounded by shells of M3C. Additionally, the microstructure contained ledeburite (M3C + γFe (austenite)). At the higher Si content of 1.6 pct, the eutectic carbides consisted entirely of M7C3, and some ledeburite remained. Last, when the Si content was raised to 2.3 pct, the eutectic carbides again consisted entirely of M7C3, but ledeburite was no longer formed. These observations can be explained in terms of the effects of Si and, to a lesser extent, of Ni on the shape of the liquidus surface of the metastable Fe-Cr-C phase diagram. The addition of Si reduces the roles played by the four-phase class IIp reactionL + M7C3 → M3C + γFe and the ledeburitic eutectic reactionL → M3C + γFe in the overall process of solidification.

Methods to identify and reduce potential surface stream water losses into abandoned underground mines

Methods to identify and subsequently seal surface water loss zones in stream channels were tested by the United States Bureau of Mines at Staub Run, a first-order stream near Frostburg, Maryland, that partially overlies abandoned coal mine workings. Conventional stream gauging was conducted to establish discharge patterns before and after stream sealing. Electromagnetic terrain conductivity surveys were performed within the stream channel to identify zones of increased relative water saturation to depths less than 15 m. Zones of increased conductivity were generally found to be associated with areas exhibiting statistically significant (P ≤ 0.05) gauged flow losses. Conversely, zones that exhibited declining conductivity delineated areas where between-station flows were not significantly different. Using this information on potential loss zones, an experimental grouting procedure was applied by injecting an expandable polyurethane grout to a depth less than one meter into the alluvial streambed over a 180-m section of the stream channel. Before grouting, the study section exhibited a 24 I/sec flow loss; first-phase grouting reduced this to a 14 I/sec flow loss; with a second-phase grouting the losses were only 3 I/sec.

Overcoring in highly stressed granite: Comparison of USBM and modified CSIR devices

An overcoring program in three nearly orthogonal boreholes, intersecting the same rock volume, was carried out in highly stressed Lac du Bonnet granite at the 240-m level of the Underground Research Laboratory (URL). The program was designed to determine if the more commonly used United States Bureau of Mines borehole deformation gauge (USBM gauge) gave similar in situ stress results as a modified Council of Scientific and Industrial Research (CSIR) triaxial strain cell. A total of 15 successful USBM tests and 17 successful CSIR tests were carried out. The measured mean stress tensor for the USBM results fell within the 90% confidence limits for the CSIR results.

Shear strength analysis of grouted coal waste materials to improve mine outslope stability: a laboratory analysis

Slope stability problems exist within the Appalachian Basin as a result of the emplacement of coal mine waste materials on mine outslopes. Prevention or elimination of slope instability problems can be costly. In an attempt to test alternative methods of slope stabilization, the United States Bureau of Mines determined some physical characteristics and shear strengths of ungrouted and polyurethenegrouted samples of coal refuse, coal spoil and natural soils collected at a number of mine outslope sites in Pennsylvania and West Virginia. The particle size distribution, per cent field porosity, per cent field water content and shear strengths of the materials were determined in the laboratory. Fifty drained direct shear strength tests were performed with the sample materials using a 0.06 m3 shear box. Tests were done at field moisture, 100% saturation and grout-infused conditions. Normal loads of 103 kN m−2, 206 kN m−2 and 416 kN m−2 were used. The grout-infused tests generally showed strength increases. An infinite slope model was used to demonstrate the potential effectiveness ofin situ grouting for a variety of field slope conditions. This modelling suggests thatin situ grouting has the potential of stabilizing slopes of up to 35° at depths of 14 m for refuse material and 30° at depths of 5 m for spoil and soil materials. The validity of these increases in material strength by grout injection will require field testing for confirmation.

Preparation of submicron titanium nitride powder by vapor-phase reactions

The United States Bureau of Mines continued research on the preparation of titanium nitride powder for potential use as a substitute for imported tungsten used in metal cutting tools and wear-resistant applications. Major emphasis was directed toward improving the purity of the powder produced by vapor-phase reaction of titanium tetrachloride with magnesium in the presence of nitrogen or anhydrous ammonia at 1000 °C. Modifications were made in powder collection, handling, and purification procedures that significantly reduced the oxygen content of the product from > >5 wt pct to <<1 wt pct oxygen. Powder samples contained oxygen contents as low as 0.23 wt pct and exhibited a median particle size of 0.28 micrometer.

The Metals Industries in the Eighties: A Preface to the Arden House Conference∗

The changing nature of the world metals industry was the subject of a three-day meeting of experts from around the world. The conference, held in May, 1986 and sponsored by the United States Bureau of Mines and the Henry Krumb School of Mines of Columbia University, included sessions on: the current status of the industries; changes in metals demand; changes in metals supply and trade; implications for the private sector; and implications for the public sector. The article introduces the issues raised at the Arden House Conference.

Test Criteria and Methodology for Evaluation of Coal Mine Monitoring and Control Systems

Field evaluation of coal mine monitoring and control systems yields data on installation and maintenance, but does not provide a full evaluation of these systems under all possible conditions. Also, the differences in installations and configurations do not allow the performance of different systems to be measured and compared. Under contract of the United States Bureau of Mines (USBM), the West Virginia University (WVU) Department of Electrical Engineering has designed criteria for evaluation of monitoring systems, and a test facility for simulation of mine conditions. This facility provides evaluation of monitoring and control systems under both normal and abnormal conditions. This paper describes the test criteria chosen, the design of the test facility, and the experiences of tests performed on mine monitoring systems to date.

In-situ stress measurement in the Carnmenellis granite—I. Overcoring tests at South Crofty mine at a depth of 790 m

A programme of overcoring rock stress measurement was conducted at South Crofty mine, Camborne, at a depth of 790 m in the Carmenellis granite to obtain information required for the Camborne School of Mines (CSM) hot dry rock (HDR) Geothermal Energy Research Programme at Rosemanowes quary in Cornwall, U.K. The measurements at South Crofty were undertaken to obtain an independent confirmation of stress magnitudes measured by hydraulic fracturing at the quarry and an indication of stress directions. Before the overcoring tests were undertaken, the geological and tectonic setting of the two sites were reviewed and it was concluded that the stress regimes should be similar. Both the Commonwealth Scientific and Industrial Research Organisation (CSIRO) of Australia and the United States Bureau of Mines (USBM) designed overcoming systems were used, with a local contractor providing the drilling services. A total of six CSIRO and seven USBM tests were successfully completed in two separate nearly horizontal boreholes with a 100° azimuth difference. Agreement between the CSIRO tests and the USBM tests was good. The mean stress tensor determined from the four best CSIRO tests was as follows (dip positive below horizontal). It is considered that the significant stress anisotropy must be due to the tectonic forces of the Alpine orogeny, and it is likely that the principal stress directions are similar at Rosemanowes and South Crofty.

Examination of the chlorate factor in electro-oxidation leaching of molybdenum concentrates using flow-through cells

A study was made of the United States Bureau of Mines' electro-oxidation process for the recovery of molybdenum from molybdenite. The investigation sought to determine operating conditions which would minimize by-product chlorate formation and the resulting loss in current efficiency. Such minimization would contribute to making the process economically attractive. It has been shown that a continuous flow-through graphite cell process produces less chlorate than either graphite or lead anode batch operations during the electro-oxidation of molybdenite at low temperatures, approximately 30°C.

Projection of diesel engine noise in mines from above-ground measurements

Underground noise levels of diesel engines were projected from above-ground measurements to set noise reduction goals meeting mine safety standards. Projection schemes applying to large spaces do not apply to most underground spaces which are tunnels (length ≫ width, height) or flat rooms (spread ≫ height). The sound-pressure level in the reverberant region of a large space is fairly constant but decreases monotonically with distance from the source along the length of a tunnel or the spread of a flat room. A method resembling that of Yamamoto [J. Acoust. Sec. Jap. 17, 26 (1961)] was used to project underground SPL for different values and combinations of the wall absorption coefficients and for various distances of the source and observer from the walls. All engines were approximated by point sources, the boundaries were replaced by an equivalent set of images, and the contributions from all sources were added in an uncorrelated fashion. Direct measurements performed at several mines support this projection method. [This work was sponsored by the United States Bureau of Mines. ]

AEROSOL DEPOSITION ON A CHARGED PLASTIC SURFACE

Annals of the New York Academy of SciencesVolume 200, Issue 1 p. 737-746 AEROSOL DEPOSITION ON A CHARGED PLASTIC SURFACE R. L. Stein, R. L. Stein Pittsburgh Mining and Safety Research Center United States Bureau of Mines, Department of the Interior Pittsburgh, Pennsylvania 15213Search for more papers by this authorW. H. Ryback, W. H. Ryback Pittsburgh Mining and Safety Research Center United States Bureau of Mines, Department of the Interior Pittsburgh, Pennsylvania 15213Search for more papers by this author R. L. Stein, R. L. Stein Pittsburgh Mining and Safety Research Center United States Bureau of Mines, Department of the Interior Pittsburgh, Pennsylvania 15213Search for more papers by this authorW. H. Ryback, W. H. Ryback Pittsburgh Mining and Safety Research Center United States Bureau of Mines, Department of the Interior Pittsburgh, Pennsylvania 15213Search for more papers by this author First published: December 1972 https://doi.org/10.1111/j.1749-6632.1972.tb40235.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume200, Issue1Coal Workers' PneumoconiosisDecember 1972Pages 737-746 RelatedInformation

Characterization of coal mine dust by computer processing of scanning electron microscope information.

Annals of the New York Academy of SciencesVolume 200, Issue 1 p. 666-675 CHARACTERIZATION OF COAL MINE DUST BY COMPUTER PROCESSING OF SCANNING ELECTRON MICROSCOPE INFORMATION* E. W. White, E. W. White Department of Material Science The Pennsylvania State University University Park, Pennsylvania 16802Search for more papers by this authorP. B. DeNee, P. B. DeNee Pittsburgh Mining and Safety Research Center Bureau of Mines, United States Department of the Interior Pittsburgh, Pennsylvania 15213Search for more papers by this author E. W. White, E. W. White Department of Material Science The Pennsylvania State University University Park, Pennsylvania 16802Search for more papers by this authorP. B. DeNee, P. B. DeNee Pittsburgh Mining and Safety Research Center Bureau of Mines, United States Department of the Interior Pittsburgh, Pennsylvania 15213Search for more papers by this author First published: December 1972 https://doi.org/10.1111/j.1749-6632.1972.tb40227.xCitations: 5 * This research was supported by the United States Bureau of Mines, under Contract No. G0101720 (MIN-40). AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume200, Issue1Coal Workers' PneumoconiosisDecember 1972Pages 666-675 RelatedInformation

Minerals: prospecting, processing and production

Abstract