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By Carlton E. Brown

This report contains information on the relation between and precision or reproducibility of counts (light-and dark-field) of the dust in liquid from simultaneous impinger, midget-impinger, electric-precipitator, and filter-paper samples. The impinger was the main sampler used from about 1922 to 1939 by industrial hygienists in the United States for collecting samples of unhygienic dust from the atmospheric environment of workers. The midget-impinger, a small modification of the preceding impinger described in 1937, has been the sampler used most since about 1939. Electric precipitators5/6/ have been used to a limited extent, mainly by the Bureau of Mines in the laboratory, for obtaining results comparable to impinger results. A filter-paper sampler for obtaining results comparable to impinger results has been described by Brown. All these samplers have a high collecting efficiency for particles larger than 1 micron in diameter revealed by the usual light-field counting procedure. However, their collecting efficiencies are quite variable for the smaller particles revealed by the dark-field counting procedure used in this study. Published information on the relation between the results of these samplers is limited and scattered. Summaries of some of this information are given in this report along with some previously unpublished information.

Jan 1, 1949

By K. C. Dean

During the investigations of the occurrence of manganese in the Western United States, a Bureau of Mines examining engineer collected samples frame two properties in Beaver County, Utah. As the ores were too low in grade to be acceptable by manufacturers of ferromanganese, beneficiation studies were made to determine the amenability of the ores to concentration. The Steelville property is about 37 miles southwest of Frisco, Utah. The deposit is an example of manganese occurring as a replacement of limestone in a bedded vein or as layers in limestone associated with shale and rock decomposition products. The Susie Q deposit, about 33 miles southwest of Milford, Utah, is also a tabular replacement deposit in limestone, apparently of limited extent. Test work was done on representative samples of 2-ton lots obtained by the examining 'engineer from each of the properties mentioned.

Jan 1, 1951

By L. B. Berger

Each winter brings its toll of deaths and serious accidents from the deadly gas, carbon monoxide. Newspapers carry warnings to the public of the dangers of this gas, and frequent now items retort the finding of persons dead or unconscious from the effects of carbon monoxide, yet these accidents continue. Either those warnings are not read, or they are unheeded by people who feel that "It can't happen to me." It can happen to you - carbon monoxide is no respecter of persons, as evidenced by items appearing daily in newspapers all over the country. Carbon monoxide has been a threat to human safety as long as man has used fire to keep himself warm and to cook his food. The burning of any fuel that contains carbon may produce carbon monoxide. This is true of solid fuels such as coal, coke, and wood; of liquid fuels such as oil, gasoline, and kerosene, and of gaseous fuels such as natural or manufactured gas. In the process of combustion the carbon in the fuel unites the chemically with tat oxygen of the air to form carbon dioxide (CO2), however, if the supply of air is not adequate, combustion is incomplete and carbon monoxide (CO) will be formed.

Jan 1, 1943

By Donald W. Ross

Petroleum oils of widely different grades have long been clarified or decolorized by contact with fuller's earths. More recently, so-called activated clays have also been used for this purpose. Still more recently ouch clays have been used in the form of nodules termed "catalytic pellets." Clays of varied appearance and from different localities possess the desired bleaching qualities, but evaluation of such clays, so useful to the oil industry, has not been simple. Previous methods of identification and evaluation have largely followed procedures of production methods and were not primarily based upon the fundamental properties of the clays. Thus) a false assumption has grown up that) bleaching clays probably have no common properties on which a-method of comparison can be based. Fuller's earths and activated clays have a large absorptive capacity for the color constituents of petroleum and its products decolorizing is accomplished by bringing the oil into intimate contact with the clay and later separating the decolorized oil from the clay with its load of absorbed coloring matter. Former practice in absorbing "color" was to use the clay as granules or In' powdered form. More recent practice is to use clay pellets that are more abrasion-resistant than the granules. The oil is either filtered through a bed of clay, percolation method, or agitated on contact with the clay, contact method. Viscous oils are decolorized at an elevated temperature, so that their viscosity is lowered to the point at which thorough contact with the clay is insured. Nonhumidifying, nonoxidizing gas, such as dry steam or dry nitrogen, is used to seal such hot oil masses from the atmosphere.

Jan 1, 1948

By Robert E. Wallhagen

The froth foam seal topping system is part of a system for remote sealing of mine passages using flyash transported pnuematically from the surface. Making the final 5 percent of the seal with a foamed-in-place fire retardant polyurethane reduces the required flyash volume by 50 percent and provides a more reliable seal. Foam components are held at the surface under proper conditions of temperature and pressure; then conveyed down the borehole through individual hoses and mixed at the bottom with a static mixer. The polyol component is pre-mixed with fluorocarbon-12 which, when released from system pressure in the mixer, boils and causes the foam to expand. Difficulties in handling this particular foam formulation are offset by a flame spread index well below the 25 level by ASTM E-162 normally required for under-ground applications. Isocyanate, polyol (TDI) and catalyst are conveyed to the downhole package by three separate lines. Five additional lines operate the valving and convey solvent so that the mixer and package lines can be flushed immediately after foaming. The eight-hose bundle is provided in segments of several lengths so that bore-hole depths can be matched. Cast-in-place plastic cylinders hold the bundle together and transfer the weight of the hose through a special quick-release clamp to the crane's wire rope. The downhole package and hose bundle are deployed using a specially designed winch and crane system capable of borehole deployment to 1500 feet.

Jan 1, 1977

By D. H. Carlson, J. H. Johnson

"The U.S. Bureau of Mines and Michigan Technological University (MTU) are collaborating to develop an apparatus for measuring diesel tailpipe emissions in underground mines. A tailpipe emissions measurement apparatus (EMA) is described that dilutes diesel exhaust and measures the concentrations of diesel particulate matter (DPM), CO, CO2, NO, and NO2 at known dilution ratios.The EMA was evaluated by side-by-side comparison of its measurements with those by laboratory grade instruments. Concentrations of CO and C02 measured by the EMA were usually within ± 14 pct of concentrations measured by laboratory-grade instruments for CO and ±20 pct for C02• EMA measured DPM concentrations were, on average, 29 pct lower than those measured by laboratory-grade instruments, with the differences being fairly consistent. The CO and C02 differences are related to the method of calculating the EMA's dilution ratio, and the difference in DPM concentrations is attributed to thermophoretic and/or condensation losses related to the EMA's unheated sample probe. Preliminary analysis of data obtained with a heated sampling probe and modifications in the sampling procedures have indicated reduced variability in DPM and in the calculated dilution ratios."

Mar 1, 1992

By A. Gene Collins

This report discusses some of the chemistry and geochemistry of cesium and rubidium. Knowledge of the cesium and rubidium content of oilfield waters aids in resolving the origin of waters and petroleum, exploring for petroleum and other valuable minerals, discovering water pollution sources, and augmenting the knowledge of geologic formations. The methods described in this report permit the detection of less than 0.01 mg/l of cesium and/or rubidium in a complex oilfield brine or water. Solvents possessing high-dielectric constants were evaluated for their ability to extract cesium and rubidium tetraphenylboron from oilfield waters and for their flame emission characteristics. Nitroethane was selected and used for the extraction and flame spectrophotometric determinations because it gave the highest sensitivity. Cesium 137 and rubidium 86 were used to determine the extraction efficiencies, which were about 87 percent and 58 percent respectively using a single 10 ml nitroethane extraction from a distilled water matrix. The standard deviation of the determination was 0.0008 mg for cesium and 0.0007 mg for rubidium in the 0.01 mg range.

Jan 1, 1965

By M. R. McKenzie

This paper describing the milling methods at the Walkermine concentrator, Plumas County, Calif., is one of a series being prepared by the United States Bureau of Mines on milling methods and costs in the various mining districts throughout the United States. ACKNOWLEDGMENT The authors wish to acknowledge their indebtedness to James O. Elton, manager of the International Smelting Co., and to Henry A. Geisendorfer, manager of the Walker Mining Co., for permission to present this paper; to H. A. Geisendorfer and J. D. Roberts, shift boss, for historical facts, and to D. D. MacLellan, geologist, for geological information.

Jan 1, 1932

By F. E. Block, Stephen D. Hill

The necessity for measuring radiation dose is encountered in studying both the beneficial and damaging effects of ionizing radiation on materials . It is also necessary to know the radiation dose absorbed by the reactants in order to evaluate the efficiency of reactions or processes that are promoted by radiation . Thus , a significant effort was made at the Albany cobalt 60 facility to investigate techniques by which the exposure radiation dose can be determined . Methods including ferrous sulfate , ceric sulfate , and methyl methacrylate chemical dosimeters , ion chamber dosimetry , and an absolute radiation calorimeter were investigated . Isodose curves were constructed for several standard source configurations using the dosimetry techniques which were investigated .

Jan 1, 1964

By K. J. Liles

The U.S. Bureau of Mines evaluated the physical properties of ceramic particulate composites made from titanium nitride (TiN), alumina (AI203), and aluminum nitride (AlN) as part of a program to meet the high-performance demands on structural materials for new and emerging technologies. Samples containing from 20 to 80 wt pct TiN were pressed and fired, and their composition, Vickers hardness, modulus of rupture (MOR), and fracture toughness were determined. X-ray diffraction and scanning electron microscope (SEM) analyses showed that, depending on the amount of TiN added, the microstructure of the samples consisted of either a titanium-aluminum-oxynitride (TiAlON) particulate in a spinel matrix or a spinel particulate in a TiAlON matrix. The best results of the physical tests were achieved on a mixture of 40 wt pct TiN, 30 wt pct A1203, and 30 wt pct AIN. Sintering aids were added in 1-and 3-mol-pct increments to the 40-30-30 mixture to determine their effect on microstructure and physical properties. Results of an analysis of variancf' on a 4 by 4 factorial analysis showed significant effects on density, MOR, and Vickers hardness.

Jan 1, 1989

By A. W. Deurbrouck

This Bureau of Mines report describes the preparation characteristics of the significant coalbeds from which samples could be obtained in Upshur County, W. Va. One of the 14 samples collected was of metallurgical quality as received, 6 could be sufficiently upgraded to provide acceptable products, and 7 could not be upgraded to metallurgical quality because of their high sulfur contents.

Jan 1, 1967

By R. E. Cumings

The Bureau of Mines made electrorefining tests in inert-atmosphere, molten salt cells to develop methods for the preparation of high-purity molybdenum. Seven of the electrolytes investigated were suitable for the preparation of refined metal. The electrolytes were composed of molybdenum chloride in alkali chlorides or mixtures of alkali and alkaline-earth chlorides. An electrolyte composed of potassium chloride and potassium hexachloro-molybdate was selected for a larger scale, more detailed study on the basis of its ease of preparation, its ability to retain the molybdenum salt, and the type of deposits obtained. High-purity molybdenum in the 99.99-percent-purity range was successfully prepared as dense plate up to 80 mils thick and as dendritic crystals. The temperature of electrolysis and the current density were major factors in determining whether plate or dendritic crystals of molybdenum were obtained.

Jan 1, 1966

By F. E. Cash

Among petroleum refinery employees and officials throughout the United States there has been marked effort to reduce accident frequency and severity. For the interest and benefit of refineries both in Louisiana and in other petroleum-refining States it has been possible to obtain from five refineries, representing 70 per cent of the production of Louisiana, tae accident experience for the past 3 to 6 years. The companies concerned have requested that their names be not used. For tide reason the four plants listed and discussed are designated as refineries A, E, C, and D. The size of the plant as regards largest to smallest number of employees is indicated by the alphabetical order.

Jan 1, 1933

Unfortunate occurrences resulting in injuries, loss of life, and destruction of property by explosion, fire, and other mishaps during shaft sinking focused the attention of the Bureau of Mines on the need for safety standards For such operations. Information Circular 7810 was published to meet that need. The current revision updates and replaces IC 7810. Several States have some rules and regulations applicable to local conditions, and several Bureau publications (including some now out of print) cover the hazards that may be encountered in shaft sinking. Certain requirements of the Federal Mine Safety Code and Federal Coal Mine Safety Act may be applied, but there are no definite, uniform standards that will guide those desiring to sink a shaft safely and bring about uniform safety inspections.

Jan 1, 1968

By Gary R. Gavan

This report presents the documentation and User's Manual for a data retrieval and report generation computer program. The program operates on a data base containing over 19,000 pieces of coal mine equipment in use in 1976.

Jan 1, 1979

By E. R. Cole

This Bureau of Mines investigation was prompted by the need forr a stable anode for electrowinning metals, particularly zinc and copper, from acid solutions. The polarization behavior of Pb-Ag (1 pct Ag) anodes in H2SO4 and fluoride solutions was determined as the first step in the development of such an anode. A Luggin capillary, dc power supply, high-impedance voltmeter, and other equipment standard to an electrochemical laboratory were used in this study. It was determined that during polarization, a relatively hard, stable coating of Pb02 was formed on the surface of the lead-silver anode and the rate of formation of this coating was considerably enhanced by the presence of fluoride ions in solution. Subsequent investigations at the Bureau of Mines Rolla Research Center resulted in the development of a Pb02-coated titanium (Pb02-Ti) anode. Results of this effort were presented in Bureau of Mines Report of Investigations 8111. Additional data resulting from extensive testing of the Pb02-Ti anodes, as well as process improvements and innovations, are included in this report. The anodes were considered generally unsatisfactory for zinc electrowinning because of lower conductivity, higher oxygen overvoltages, and shorter in-cell life as compared with the Pb-Ag anodes now being used in industry. However, the PbO2-Ti anodes were used successfully to oxidize waste chromium solutions and to electrowin copper.

Jan 1, 1981

By David E. Siskind

A Bureau of Mines survey of noise from quarry production blasting was conducted at seven crushed-stone quarries, providing information on close-in noise generation, comparative instrumentation, and evaluation of the sound levels as related to blasting parameters and existing State and local noise standards. The results from this preliminary survey will be useful in the design of a complete investigation of the problem of noise from blasting. There exists an immediate need for technical guidelines for noise pollution control agencies presently working on the regulation of impulsive noise sources. This survey and results from previous work by other researchers are used to derive interim recommendations on weighting scales, generated sound levels, and instrumentation. These recommendations are based on the limited data presently available and may be modified with subsequent investigation of noise generation, propagation, structural damage, and human tolerance.

Jan 1, 1974

By J. J. Sammarco

Light emitting diodes (LEDs) are emerging as viable replacements for incandescent-based cap lamps used in mining. The photometric and energy characteristics of these light sources differ in important ways. The present paper describes the performance of LED and incandescent sources in cap lamps in terms of correlated color temperature, color rendering, light output, electric power, ambient temperature and airflow, and light source aging. Importantly, these characteristics can influence a miner?s ability to spot mining hazards thus impacting safety. Secondly, some of these characteristics interact with the operating life of the cap lamp?s battery power, such that differences between LED and incandescent sources can be magnified toward the end of a 10­hour battery discharge cycle. Empirically, we have determined that after 8 hours at an ambient temperature of 25 °C, the average light output of an incandescent cap lamp can decrease to about 69% of its initial value when powered by a lead-acid battery and it can decrease to about 65% of its initial value when powered by a nickel-hydride battery. An LED-based cap lamp using a constant current drive circuit can maintain about 96% of its initial value when powered by a nickel-hydride battery. Real-world tests addressing the effects of ambient temperature and airflow on the light output of an LED and incandescent cap lamp were conducted in the NIOSH Safety Research Coal Mine (SRCM). The LED cap lamp yielded a vertical average illuminance improvement of approximately 9.5% and the INC cap lamp yielded a vertical average illuminance degradation o f approximately 4%. The differences between LED and incandescent cap lamps were further quantified by the calculation of ?mesopic luminance? data that indicated for the same photopic luminance (i.e., as measured using a conventional light meter) the LED cap lamp could be up to 38 % more efficient than the incandescent cap lamp with a lead-acid battery at the end of the 10-hour driving cycle. Lastly, accelerated life tests were used to empirically determine light output depreciation as the incandescent light source age approached its useful life. There was about a 35% decrease in light output. This is quite considerable, especially given that the light output will decrease an additional 30% to 45% over the period of a 10-hour shift. The implications of the differences between LED and incandescent sources are discussed. This information is crucial in determining how visual performance could be affected for real-world conditions where batteries discharge during the work shift and as the light source ages. To date, only idealized conditions have been used for LED and incandescent cap lamp visual performance research.

Jan 1, 2008

By Oliver Bowles

From the most remote periods of civilization, stone Las been used to perpetuate the memory of individuals or to immortalize their noble achievements. Ancient memorials ranged from simple piles of stone (cairns) or single markers to great obelisks and pyramid or magnificent mausoleums. The Taj Mahal at Agra, India, built of white marble by Shah Jehan in memory of the Empress Mumtaz Mahal, is one of the most beautiful and costly memorials ever built. It was erected between 1632 and 1050 at a cost estimated at a: high as $50,000,000, and it is today an object of unusual attraction for travelers. Other magnificent memorials, both ancient and modern, are to be found in many lands. Memorials of varying design have characterized the passing centuries and have found an important place in the New World. In early days, monuments were chiefly imported into America, but gradually an extensive memorial stone-manufacturing industry developed on this side of the Atlantic. Sales value of domestic memorials, f.o.b. quarry or mill, attained a maximum of $17,488,755 in 1920, and retail sales, of course, reached a much higher figure. Modest markers and tombstones are to be found in almost every rural community in the United States, and there are many elaborate and costly monuments in and near urban centers.

Jan 1, 1938

By A. J. Kraemer

This report on the physical and chemical properties of crude oils of California is one of a series on the producing districts of the United States. It includes a short discussion of results, tabulated data, and individual analyses of California crudes. Analyses of crude oils from the fields of Fresno, Kern, Los Angeles, Orange, and Ventura Counties have been published in Serials 25952 and 26083. The analyses reported in this paper corer samples that were obtained subsequent to the publication of Serials 2535 and 2608. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting of samples was facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1927