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By E. H. Denny

Colorado coal-mine fatalities, which have gradually decreased since 1914, have shown a marked decline since 1924. Data on coal-mine fatalities in Colorado published by the U. S. Bureau of Mines5 indicate that the deaths per thousand 300-day workers have decreased from 9.13 in 114 to 6.14 in 1926, and that the deaths per million tons produced have decreased from 9.18 in 1914 to 4.98 in 1926. Table 1 gives fatality rates in Colorado and in the United States from 1914 to 1926 inclusive. [ ]

Jan 1, 1929

By R. Karl Zipf

In some instances, extensive room-and-pillar working scan collapse with little warning and pose a serious risk to underground miners. Traditional strength-based pillar design methods applicable to coal or hard-rock mines use a factor of safety defined as pillar strength divided by pillar stress. Factor of stability, defined as local mine stiffness divided by post-failure pillar stiffness, may offer a way to design room-and-pillar mines and eliminate collapses. Three alternative design approaches to decreasing the risk of large-scale catastrophic collapses are described: the containment approach, the prevention approach, and the full-extraction approach. Until good data on the post-failure behavior of pillars become available, the containment and full-extraction options are the safest. The limitations in our ability to evaluate both the stability of old workings and the long-term performance of room-and-pillar mines are described.

By M. S. Seehra, R. S. Pandurangi

"INTRODUCTION Silica and kaolin (a layer aluminosilicate) are among the major constituents of most coal mine dusts.' Whereas kaolin is cytotoxic in vitro but nonfibrogenic in vivo in humans and experimental animals,2-4 the cytotoxic and fibrogenic potential of silica is rather well established.5 Wallace and co-workers 6-8 have studied the cytotoxic potentials of both native and surface-modified silica and kaolin and inferred that retoxification is slow in the case of occluded silica vis-à-vis native silica. Recent epide¬miological studies indicate that silica concentration alone in a mine dust, as determined by transmission IR spec¬troscopy (TIRS), does not correlate well with the pro¬gression of coal workers' pneumoconiosis. 9 This obser¬vation has led to the suggestions that silica particles occluded by clays such as kaolin may not be fibrogenic. This proposal requires accurate estimations of kaolin, silica, and occluded silica. The current method of silica analysis in a mine dust sample employs TIRS of the 797- cm -1 band of silica, although its accuracy, as well as that of x-ray diffraction studies, is no better than 25 % , even in a laboratory-generated dust.° In this paper we have employed the techniques of diffuse reflectance spectros¬copy (DRS) and photoacoustic spectroscopy (PAS), in conjunction with an FT-IR spectrometer, for the quan¬titative determination of silica in laboratory-generated silica-kaolin mixtures.One of the main advantages of DRS and PAS is that, in these techniques, problems arising from sample prep¬aration of the KBr-based disks used in TIRS are avoided. There are, however, several other considerations (e.g., particle size effects and saturation phenomenon) which complicate the use of DRS and PAS for quantitative work. 10-25 In this paper, we have carried out a systematic comparison of the quantitative abilities of the two tech¬niques, as applied to the silica-kaolin mixtures, with par¬ticular attention to the saturation behavior of several bands with different absorption coefficients. In particular, we show that a weaker band for silica at 1875 cm-1 is suitable for quantitative purposes, and that quantitative accuracy is higher in DRS than in PAS. Details of this work are given below."

Mar 1, 1992

By H. C. Ko

Calorimetric determinations of low-temperature heat capacities and standard enthalpy of formation were made by the Federal Bureau of Mines for basic aluminum sulfite, A1203?2.0S02?5.3H20. The standard values of entropy (S°), enthalpy of formation (?Hf°), and calculated Gibbs energy of formation (?Gf°) at 298.15 K are 85.2±0.1 cal/deg-mole, -943.1±1.2 kcal/mole, and -820.7±1.2 kcal/mole, respectively.

Jan 1, 1976

By C. H. Elder, Maurice Deul

A 5-hole pattern was drilled from the surface at a site near Oak Grove, Jefferson County, Ala., to degasify the gassy Mary Lee coalbed in advance of mining. Gas and water production was monitored for 1 year, 4 months to allow gas flow to stabilize fully. A thickened water stimulation treatment was designed and applied in one hole of the pattern to evaluate this degasification technique for the Mary Lee coalbed. A gas production rate of 70,000 ft3 /day after stimulation treatment indicates that the use of vertical boreholes coupled with hydraulic fracturing in advance of mining the Mary Lee coalbed would provide for more rapid degasification and could provide a possible source of natural gas.

Jan 1, 1974

By D. J. Bauer

A primary amine extraction system was investigated for fractionating a cerium-group, lanthanide sulfate mixture. Addition of diethylenetriaminepenta-acetic acid (DTPA) to the amine extraction system resulted in separation factors as high as 5.4 for lanthanum-cerium, 8.0 for cerium-praseodymium, 3.7 for praseodymium-neodymium, and 7.0 for neodymium-samarium. In multistage studies on a cerium-free lanthanide mixture, 96 percent of the lanthanum was recovered with a purity of 95 percent.

Jan 1, 1968

By N. S. Dalal, X. Shi

"With a view of elucidating the role of glutathione (GSH) in the biochemical pathways of the chromate-exposure related carcinogenesis, we carried out electron spin resonance (ESR) spectroscopic investigations of the chromate-GSH redox reactions. The ESR measurements, employing spin-traps, provide evidence for the involvement of the glutathione (GS•) radical, as well as an isolable Cr(V)-glutathione intermediate. These results indicater a new mechanism for the reduction of chromate by GSH in cellular environment and help understand the (unexpected increase in Cr(VI)-induced DNA strand breaks at elevated GSH levels.We report here indirect electron spin resonance (EGR evidence for the involvement of the glutathionyl (GS) radical and direct evidence for a Cr(V) intermediate in the reactions of glutathione ¬(GSH) with chromate for the first time.. This work was undertaken to clarify the biochemical pathway of the reduction of chromate by GSH, since this reduction process is thought to be a critical step in the pathogenesis of the chromate-exposure related carcinogenesis. This follows from the literature reports which show that (a) Cr(VI)compounds have been proven to be carcinogens in laboratory animals as well as in human studies2-4, (b) Cr(VI) and not Cr(III) compounds are mutagenic 5-7, (c) Cr(VI) and not Cr(III) compounds can penetrate cell membranes 8.9 (d) the final state of Cr(VI) in cellular reductions is Cr(III)', (e) by itself chromate (or Cr(VI)) cannot be directly mutagenic since Cr(VI) is known not to interact with isolated DNA under physiological conditions 10, suggesting the significance of Cr(VI).reduction processes. One of the major reductants in cellular environments is thought to be the GSH, both outside and inside the ce11s 11-13. Other evidence for the role of GSH in the chromate toxicity is seen from recent studies showing that exposure of hamster cells to non-toxic levels of added selenite increases the levels' of GSH as well as the Cr(VI)-induced DNA strand beaks 14, and thatsuch DNA strand breaks in hepatocytes also change in direct proportion to their GSH content 15,16. These observations wereinterpreted as implying that the reduction of chromate by GSH, to some reactive intermediate is an important step in the chromatecarcinogenicity 15,16. The following reaction steps were,suggested 15, 16"

Jan 1, 1988

By Raymond M. Stateham

Calculations based on data obtained from measurements of smoke from coal-fired powerplants predict that infrared imagers will be useful tools for smoke vision. Infrared imagers operating in the 3-to 5-um spectral region have been evaluated for this purpose. A mine opening 110 meters long was filled with smoke from burning coal, and two men, wearing breathing apparatuses, moved through the smoke to serve as targets. The men were detected and identified at 80 meters.

Jan 1, 1976

By Wilder D. Foster

In estimating the hazardous qualities of a dusty atmosphere it is frequently desirable to determine the composition of the air-borne dust. Samples collected from ledges or from the rock itself are Likely to be unsatisfactory for this purpose owing to the possibilities of differential disintegration of the rock and of variations in settling rates of the different components of the minerals. It may be necessary, therefore, to collect samples of dust from the air. Samples collected from the air may be analyzed chemically, by X-ray diffraction, and by the petrographic microscope. Chemical methods are unsatisfactory owing to the small samples usually available and to the limitations and complexities of: present methods. X-ray technique requires expensive apparatus not ordinarily available except in research laboratories. Owing to the simplicity and rapidity of petrographic is examination of atmospheric mineral dusts, it was considered worthy of further study.

Jan 1, 1938

By Curtis A. Jones

Continuing interest has been shown in developing processes for extracting nickel and cobalt from low-grade domestic deposits of these metals and in improving existing methods. Of special concern is the nickel-recovery installation at Nicaro, Oriente Province, Cuba, operated for the General Services Administration. The Bureau? of Mines felt that a bibliography would help familiarize personnel at various Bureau of Mines stations and General Services Administration contractors with extraction methods both in the United States and in foreign countries. When this task was under way it became apparent that to compile a complete bibliography would require considerable time, so it was decided to limit the first part to the later literature and issue it independently, thus making it available sooner. The present work supplements the first part and extends the coverage to the earliest years of nickel and cobalt metallurgy.

Jan 1, 1959

By James P. Bennett

The Bureau of Mines investigated the effect of refractory oxide additions, introduced in soluble form, on the high-temperature properties of 90- and 98-pct-MgO brick. Brick samples were soaked in solutions containing Al, Ca, Cr, Co, Fe, Mg, Mn, Mo, Ni, Si, Sr, Sn, Ti, or Zr ions. Additions to 98-pct-MgO brick did not generally result in statistically significant property improvements. Statistically significant improvements were noted in hot modulus of rupture (MOR), slag resistance, and spalling resistance of the 90-pct-MgO brick for additions of Al, Mg, or Sn. High-temperature performance of treated 90-pct-MgO refractories was equal to or approached that of 98-pct-MgO brick. The marked improvements due to tin were obtained with additions of only 1.14 wt pct Sn02.

Jan 1, 1985

By John C. Machisak

INJURY DATA and experience at coal mines in the United States for 1957 are presented in this bulletin under the following general sections: (A) General injury experience: Tables 1-6: Current data on number of fatal and nonfatal injuries, frequency and severity rates, and average severity. (B) Selected injury experience: Tables 7-36: Current data on causes of injuries, distribution of injuries by part of body injured, days of disability, extent of hand and machine loading, experience by employ¬ment and production groups, and various other operating factors and physical conditions related to the occurrence of injuries at the Nation's coal mines. (C) Injury experience, by States: Tables 37-41: Data on injuries, injury rates, employment, causes of injuries, and severity rates. (D) Major disasters: Table 42: Data on major disasters from 1948 to 1957. A major disaster is defined as a single accident in which, or as a result of which, five persons or more are killed instantly or die at any time thereafter. (E) Historical coal-mine-fatality experience: Tables 43-47: Data on fatalities and their causes at bituminous-coal, lignite, and anthracite mines from the earliest records through 1957.

Jan 1, 1960

By Dennis A. Long

"The size of off-highway trucks has increased substantially over the last decade, bringing about a radical change in truck maintenance practices and procedures. As a result, surface mine maintenance mechanics today are faced with the increased hazards of working with larger and heavier tools and components and doing repairs at greater heights, thereby exposing them to a high potential for serious injury or death. Not surprisingly, the number of accidents involving truck maintenance mechanics is significantly increasing.The Bureau of Mines has assessed the haulage truck maintenance safety problem, analyzing maintenance-accident data over the 7-yr period, 1978- 84, in terms of personnel, job activities, truck components and systems, tools involved, and truck design. This assessment, based on the review and interpretation of 1,225 haulage truck maintenance accident reports, identified major factors contributing to these accidents. Overall, young, inexperienced workers are involved in most accidents. A typical maintenance accident involves a male mechanic under 33 yr old, with less than 5 yr job experience. INTRODUCTIONOver the past decade, surface mine maintenance and repair operations have changed radically. The number of maintenance personnel has grown along with the hazards of working with larger and heavier components at greater heights and with larger and heavier tools. Furthermore, transfer of skills from over-the-road vehicle mechanics is not as feasible as it once was, because of the ever increasing size of mining equipment and the complexity of its design. In short, surf ace mine equipment maintenance and repair has become increasingly sophisticated as well as labor intensive, necessitating further research and evaluation in terms of both safety and efficiency (1, 7-8) 2"

Jan 1, 1986

By Wilder D. Foster

In estimating the hazardous qualities of a dusty atmosphere it is frequently desirable to determine the composition of the air-borne dust. Samples collected from ledges or from the rock itself are likely to be unsatisfactory for this purpose owing to the possibilities of differential disintegration of the rock and of variations in settling rates of the different components of the minerals. It may be necessary, therefore, to collect samples of dust from the air. Samples collected from the air may be analyzed chemically, by X-ray diffraction, and by the petrogrephic microscope. Chemical methods are unsatisfactory owing to the small samples usually available and to the limitations and complexities of present methods. X-ray technique requires expensive apparatus not ordinarily available except in research laboratories. Owing to the simplicity and rapidity of petrographic examination of atmospheric mineral dusts, it was considered worthy of further study.

Jan 1, 1938

By M. B. Cooke

An analytical method for the determination of the gum-forming material in gasoline has been developed by the Bureau of Mines, during a study nor in progress to determine the best rays for elimination of such constituents from gasoline. This method is similar in principle to that previously described by Smith end Cooke,2 which involved evaporation of e sample of gasoline in a small glass dish. The evaporation was started on an actively boiling steam bath and completed in an air oven at 105°C. In the improved method described below, the stem bath has been replaced by a steam heated oven in which an inert atmosphere is maintained. Air is excluded from the oven, consequently the precision of the determination is increased. Furthermore, evaporating dishes different from those previously described may be used.

Jan 1, 1925

By R. A. Cattell

The Bureau of Mines recently observed its fortieth anniversary, and with the close of the fiscal year 1950 it completed 36 years of close cooperation with and helpfulness to the petroleum and natural-gas industries, whose technical problems it studies. Petroleum people likewise observed the ninetieth anniversary of the start of this truly American industry when "Colonel" Drake drilled the first well at Titusville, Pa., in 1859 (see fig. 1). Throughout the period, during which there have been many changes in the fuel and related economy of the country, this work has been carried on systematically by an organized entity of the Bureau first known as the Petroleum Division and in recent years as the Petroleum and Natural Gas Branch. Changes in the industries have been brought about partly by economic forces, partly by advances in technology, and in some measure by the impact of two world wars. As the needs of industry and the Nation have changed, so have the studies of the Bureau changed to meet these needs. Consistently, Bureau technologists and scientists have tried to keep in step with progressive movements; frequently, in fact, have taken the lead. Wherever possible, they have looked far ahead in their program of research, at the same time recognizing the needs of the hour.

Jan 1, 1951

By J. A. Sutton

In connection with, a stream-pollution-research project, a colorimetric method was developed for concentrations of 1 to 30 p.p.m, of pine oil in water. The method depends on the stable bluish-green color produced when pine oil is reacted with vanillin-hydrochloric acid reagent at 60° C. for 25 minutes. The colorimetric reaction actually determines alphaterpineol, the principal component in pine oil. Some waters may require a special preparation in which ion-exchange resins are used to remove interference. ACKNOWLEDGEMENTS The author wishes to express his appreciation to A. A. Berk, chief of the Industrial Water Branch, Bureau of Mines, for helpful advice and encouragement during the progress of this work and to B. P. Martinez, chief of the Stream Pollution Research Section, for assistance with the manuscript. Thanks are also due to W. D. Bishop of the Hercules Powder Co., Wilmington, Del., for supplying the principal components of pine oil.

Jan 1, 1953

By John C. Machisak

THE INJURY data and experience at quarries and related plants of the United States are presented in this publication under the following general sections : (A) General injury experience: Tables 1 through 3: Contain current data on the number of injuries, injury-frequency rates, location, accident agency, degree of injury, and related employment data. (B) Injury experience at different kinds of quarries: Tables 4 and 5: Contain current data on number of injuries, injury- frequency rates, location, accident agency, degree of injury, and related employment data. (C) Injury experience by States: Tables 6 through 19: Contain current data on the number of injuries, injury-frequency rates, accident agency, degree of injury, and related employment data.

Jan 1, 1959

By P. E. King

The U.S. Bureau of Mines is conducting an ongoing research project to better understand the phenomena involved within electric arcs utilized in electric furnace steelmaking. With a better understanding of the physical and electrical characteristics involved, dynamic or predictive control of electric arc furnaces may be possible. A mathematical model is presented, but not solved, and the system of coupled equations is analyzed. Characteristic parameters are used to determine relative importance. In this manner, significant quantities are dermed. The parameters found to contribute little to the system of equations of motion are ignored. A resultant simplified system is identified, and directions for further study are indicated toward control of electric arc furnaces.

Jan 1, 1990

By Clarence O. Babcock

Model pillars of limestone, marble, sandstone, and granite having length to diameter ratios of 3:1, 2:1, 1:1, and 0.5:1 were broken in axial compression to determine whether lateral end constraint affected the breaking strength. Steel rings bonded to the ends of the model pillars with epoxy provided, during the loading cycle, a lateral end constraint of about 17 to 30 percent of the average axial stress. The effect of this constraint was to increase the breaking strength of the rock as compared to cylindrical pillars without constraint. The percentage increase in breaking strength varied with rock type and increased as the length to diameter ratio decreased. The maximum increase in breaking strength was 35 percent for marble pillars having a length to diameter ratio of 0.5:1. A theory was developed which relates the expected constraint to the physical properties of the ring and rock.

Jan 1, 1968