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By Donald R. Johnson

Apparatus developed by the Bureau of Mines for thermal analysis of oil shale was used to determine the thermal properties of shortite. Dissociation of shortite near 470° C occurs as an endothermic reaction that could consume significant quantities of heat in the oil-shale retorting process that produces shale oil. The shortite dissociation products undergo other thermal reactions that would not affect the retorting process. These reactions include crystal inversions near 365° C and 425° C and melting and decomposition endotherms above 500° C. Two separate reaction route for fusion and decomposition of the shortite decomposition products are dictated by the presence or absence of CO2 around the sample.

Jan 1, 1974

By Fred N. Kissell

The new MSHA diesel rules have stone mine operators looking hard at pos¬sible upgrades to their ventilation systems. There are existing methods to reduce diesel engine emissions (MSHA, 2001)(Head, 2001b),but many operators will decide that a ventilation upgrade is necessary is well. NIOSH hay several stone mine ventilation projects underway, but in the meantime a good information resource is the work done by the U.S. Bureau of Mines in the 70's and 80's on ventilation for oil shale mines. The Bureau conducted this research because oil shale mines were projected to be gassy and would, therefore, require a lot of ventilation air. The focus of this oil shale work was on the use of jet tans for lace area ventilation, and on stoppings that would he low Lost and leak-tight. The work also considered changes in mine design to reduce the number and size of stoppings. The findings are still applica¬ble to stone mines.

Jan 1, 2002

By M. W. Von Bernewitz, E. H. Denny

The use of oxygen breathing apparatus during rescue and recovery operations at both coal and metal mines has become so commonplace that there is a tendency for the industry not to give such apparetus the full measure of credit that it deserves in any particular disaster , therefore , the data presented herein should give some idea of what has been done in this regard during the past 15 years that is , up to 1910 by the Technologic Branch of the U. S. Geological Survey , and thence ( to the end of 1922) by the U. S. Bureau of Mines .

Feb 1, 1923

By T. C. Phalen

"Necessary Qualities There mines are located in out of the way places, where timber is scarce and its price high, the problem of protecting it from fire risk is of considerable practical importance. Scarcity of timber for mining purposes is commonly met with in the more arid parts of the country, where, also, mine timbers are most likely to become dry, and inflammable, and where, therefore, the risk from fire is accentuated. Any effective and cheap method of securing adequate protection of such timber at the lowest possible cost is worthy of careful investigation. The use of magnesite cement has been suggested in this connection.The necessary qualities for any substance for the use suggested above may be summarized as follows: It should be resistant to abrasion, and to impact and structural stresses. It should be durable when subjected to the action of the ele¬ments, and stable to any minor derangements of the base on which it is placed. It must be relatively unaffected by changes in temperature, by the action of water, and should adhere to the material on which it is placed, and it should also be free from shrinkage cracks due to setting up the material, Magnesite cement appears to fulfill the various conditions outlined above.The elasticity of such cement is the outstanding quality which makes it desirable for exterior work. It also possesses the ability to adhere to all materials in a marked degree. Its freedom from expansion and contraction after setting is one of the principal reasons for its adhesive quality. It may be applied to old brick or stone walls, even tho they have been repeatedly covered with paint, and the quality of ad-hearing to wood makes it possible to secure a weather-proof protection to the wooden casings and trim of exterior openings. The quality of adhesion and elasticity is easily proved by applying a 1/2"" layer to a 1"" board which has been first covered with metal lath. Such a board, about 8 feet long, may be repeatedly deflected about 3"" in the center without breaking the bond to the board, or causing any cracks to appear in the magnesia cement. The ability to resist fire as well as the possession of insulating qualities are also desirable characteristics of magnesia cement stucco."

Dec 1, 1919

By C. Özgen Karacan

Methane emissions from a longwall ventilation system are an important indicator of how much methane a particular mine is producing and how much air should be provided to keep the methane levels under statutory limits. Knowing the amount of ventilation methane emission is also important for environmental considerations and for identifying opportunities to capture and utilize the methane for energy production. Prediction of methane emissions before mining is difficult since it depends on a number of geological, geographical, and operational factors. This study proposes a principle component analysis (PCA) and artificial neural network (ANN)-based approach to predict the ventilation methane emission rates of U.S. longwall mines. Ventilation emission data obtained from 63 longwall mines in 10 states for the years between 1985 and 2005 were combined with corresponding coalbed properties, geographical information, and longwall operation parameters. The compiled database resulted in 17 parameters that potentially impacted emissions. PCA was used to determine those variables that most influenced ventilation emissions and were considered for further predictive modeling using ANN. Different combinations of variables in the data set and network structures were used for network training and testing to achieve minimum mean square errors and high correlations between measurements and predictions. The resultant ANN model using nine main input variables was superior to multilinear and second-order non-linear models for predicting the new data. The ANN model predicted methane emissions with high accuracy. It is concluded that the model can be used as a predictive tool since it includes those factors that influence longwall ventilation emission rates.

"""Hazard"" is the general expression used by safety engineers to denote risk, or the danger to property or human beings from the contingencies peculiar to different industries. Where a business, family, or individual is subjected to possible financial loss from any particular hazard, it is customary and is considered good practice to insure for reimbursement of possible loss. Accordingly, we take out insurance for earthquakes, for fire, for accidents, etc., and are charged a different premium for each. The premium rate is based on our relative exposure to the hazard in comparison to the total loss to our particular class of business in our geographical location over a given period.Insurance, then, must be considered as the experience of a group rather than of an individual, and any individual may be fortunate or unfortunate over stated periods. Through the law of averages, the probability of loss because of exposure to hazard is becoming more accurately measured as experience is accumulated and data are analyzed.Lion human life came to have a financial value in the eyes of the law, and employers were held liable for losses through accidents to employees while on duty, insurance companies began to underwrite the accident risks of the different employers and divided them into classes based on the amount of risk involved. Premiums for compensation insurance are based on relative exposure, which is measured by pay roll. The premium is rated in proportion to the severity of losses established by statistical studies.' It soon became evident that the accident experience of employers in the some industry varied widely; that is, there were good and bad risked in the same line of business. This resulted in ""experience rating"" of premiums, meaning thereby that an employer with experience in accident cost was premium rated in proportion to his losses over a stated period (usually three or more years)."

Feb 1, 1926

"INTRODUCTIONThe information compiled in this volume initially formed the response by the Generic Mineral Technology Center for -Respirable Dust (GTCRD) to a review of its research and technology transfer programs performed in 1990 by the Advisory Committee on Mining and Mineral Resources Research. This review for each mineral technology research center is accomplished, as required of the Bureau of Mines by the House/Senate Joint Conference Committee, through site visitation to the research institutions of the GTCRD and an in-depth questionnaire. The information provided by that questionnaire becomes an important factor in their recommendations concerning future directions of the program.The site visitations took place during January and February 1991 at the Milton S. Hershey Medical Center~ The Pennsylvania State University, West Virginia University, University of Minnesota, and Michigan Technological University, in addition to an in-mine visit conducted at the Loveridge Mine in West Virginia. The questionnaire was prepared and made available to the Advisory Committee and the Research Council for their review at the GTCRD annual project review meeting in Hershey, Pennsylvania, in April 1991.The comprehensive nature of the questionnaire and the scope of the information contained therein make it an excellent retrospective of the Center. Having a clear vision of where the Center has been and knowing where it is now helps to guide it into the future. It is believed that such a detailed view of the Center's facilities and research program will be of value to Center personnel and Advisory Committee members. Each aspect of the questionnaire was examined, answered in detail and documented thoroughly. With the completed questionnaire as a guide, this review of the Center's activities provides an update to Respirable Dust Center Research Program Review 1988, published in 1989 as the seventh of the Generic Mineral Technology Center for Respirable Dust volumes. As does that volume, this review presents the complete General Mineral Technology Center questionnaire, with the GTCRD's expanded responses and supporting documentation appended. An examination of the research program, Center personnel currently active on GMTC projects, the number of graduate degrees granted with GMTC supports GMTC publications, the degree of individual interaction, technology transfer activities, the reference center, GMTC equipment and facilities, and envisioned plans for future research directions provides updated information in these areas. In addition, this year, information has been included to demonstrate the interaction between the Center's goals and its research projects, with thorough consideration of actual research needs as specified by the National Academy of Sciences. This volume serves as a review of the years 1989 through 1990, the sixth and seventh years of the Center's operation."

Jan 1, 1990

By Scott W. Hazen

This report presents the results of a statistical analysis of a limited amount of sample and assay data from a production panel in an open - pit phosphate mine in the Phosphoria formation in Idaho . A frequency distribution analysis is shown for the assays , sample interval lengths , and products of assay and sample interval length for the millshale , furnace - shale , and main phosphate beds . Correlation techniques were used to show the relationships between assays and sample interval lengths . Within- drill - hole and between - drill - hole correlation were also examined as a means of predicting grade trends in the ore . Simulation methods , utilizing a digital computer , were used to establish assay populations that could be used for estimating grade of ore , cutoff grades , and deposit or bed identification .

Jan 1, 1964

By D. K. Dysinger

In this U.S. Bureau of Mines study, neodymium metal of 99.8 pct purity was prepared by electrolysis of Nd203 salts dissolved in a molten fluoride electrolyte. The metal was electrowon in a molten state at current efficiencies of 50 to 60 pct. Oxygen and carbon were the major impurities detected in the product. During operation of the small-scale laboratory cell, a number of technical problems including anode effect, low oxide solubility in the electrolyte, high neodymium metal solubility, reactivity of the metal with the cell materials, and back reaction of the metal with the anode gases were encountered. Approaches to improve cell operation and prospects for commercial adoption of the electrolytic production of neodymium metal are discussed.

Jan 1, 2010

By G. S. Scott, G. W. Jones

Trichloroethylene (CHC1CC12) is an important solvent for fats , resins , bitumens, rubber , sulfur , and phosphorus . It is used extensively in drycleaning because of its low order of combustibility and has recently been proposed as an inhalation anaesthetic . Its physical properties have been described by Carlisle and Levine . It is usually considered a noninflammable material ; however , substances that are noninflammable when mixed with air are not necessarily noninflammable when mixed with oxygen . Thus , Hewer's statement that " Trichloroethylene*** is not inflammable under any circumstances , nor will its vapor explode when mixed in any proportion with air , oxygen, or nitrous oxide , " requires qualification , especially in anesthesia, where pure oxygen may at times be substituted for air , This report gives the results of tests made to determine the inflammability of trichloroethylene in various mixtures of oxygen and nitrogen . The trichloroethylene used was Eastman's No. 1300. The boiling point was given as 86 ° to 87 °C . The specific gravity and refractive index of the sample measured in this laboratory were , respectively, 1.45 and 1.4759 at 25 °C .

Nov 1, 1942

Remotely monitor overburden response to longwall mining using time domain reflectometry (TDR) and a combination of hardware and software, as part of the U.S. Bureau of Mines (USBM) program to characterize subsidence. Background TDR was developed in the 1960's as a method to locate, discontinuities in coaxial transmission cables. In this method, voltage pulses sent along a cable are reflected by cable defects. The pulse reflections are used to determine the type and magnitude of the defects. The TDR concept was extended to material property measurement by embedding cables into particular materials and evaluating the cable's dielectric behavior as material properties were modified. This technique was adapted by the USBM in 1978 for use in monitoring rock movement during underground mining. The same concept is utilized today. A coaxial cable is grouted into a rock mass that is expected to deform. Progressive rock movement causes the cable to deform, as shown in figure 1, and changes to occur in the cable's electrical properties, which then produce changes in TDR reflection signatures. The technology has advanced to the point where it is now possible to distinguish shear deformation from tensile deformation and to quantify rock mass displacements by analyzing the TDR signatures.

Jan 1, 1995

Reduce the dust exposure to the operator of a longwall shearer with a novel foam spray system. Approach Discharge foam through the nozzles of a shearer drum so that foam and coal are better mixed. How It Works Bureau of Mines research showed that two very important principles for successful application of foam are: (1) moisture distribution and (2) degree of mixing. Foam can distribute a given quantity of moisture much more evenly over a large surface area. Successful Bureau tests of foam for dust control always involve a high degree of mixing between the foam and the material, Mixing, permits a greater distribution of foam throughout the mined product. The most suitable location of foam application would be at the point where the dust is generated, before the dust becomes airborne. Foam nozzles located in the cutter drum (pick face foaming or ejecting foam through scroll sprays) will suppress dust close to its source.

Jan 1, 1989

By William H. Schiffbauer, William D. Mayercheck, August J. Kwitowski

This report summarizes work sponsored by the Bureau of Mines in the development of a remote operating system (ROS) for controllng a thin-seam continuous miner (TSCM) 500 feet or more distant from the extraction face. Detail s are provided on ROS subsystems including the continuous miner, video equipment, controls and displays, the electronic control system, and the operator station.

By J. W. Eckerd

Metal production rates of 42 to 45 tons per day were obtained with hollow-core anthracite briquets in an experimental blast furnace. Tuyere pressures were about the same for both coke and briquet operations, but from 150 to 175 pounds more of briquets were required per ton of metal than were needed with coke. Furnace operations were comparatively smooth, furnace hanging occurring less often than in previous tests with anthracite briquets. Dust production was substantially higher than with coke, however, and metal quality could not be controlled by corrective burdening and moisture control.

Jan 1, 1968

By Thomas V. Falkie, R. Venkataramani

The empirical nature of this investigation required measurements of variables under operating conditions in underground coal mines. The variables to be measured were based on the postulated character¬istics of the loading function, as described in the previous chapter. One class of variables presumed to influence the loading function are geological variables. Accordingly, the sites for data collection were selected in different bituminous coal seams at dispersed locations in order that variation in geological conditions would exist. Seven mines in central and western Pennsylvania and one mine in northern West Virginia were selected as data collection sites. Five different coal seams were represented by these mines. The remaining classes of variables - geometric, mechanical, and procedural - were measured as they occurred in the mines. A description of the measurements, and the conversion of these measurements to forms which could be-analyzed for effect on the loading function is given. Mining Dimensions At the underground working face, the following dimensions were measured: a. Thickness of coal excavated. b. Thickness of shale excavated. c. Total height excavated. d. Width excavated. e. Depth of penetration of each machine cut. With the exception of the last of these dimensions, all were measured

Jan 1, 1972

"There mines are located in out of the way places, where timber is scarce and its price high, the problem of protecting it from fire risk is of considerable practical importance. Scarcity of timber for mining purposes is commonly met with in the more arid parts of the country, where, so, mine timbers are most likely to become dry, and inflammable, and where, therefore, the risk from fire is accentuated. Any effective and cheap method of securing adequate protection of such timber at the lowest possible cost is worthy of careful investigation. The use of magnesite cement has been suggested in this connection.The necessary qualities for any substance for the use suggested above may be summarized as follows: It should be resistant to abrasion, and to impact and structural stresses. It should be durable when subjected to the action of the elements, and stable to any minor derangements of the base on which it is placed. It must be relatively unaffected by changes in temperature, by the action of water, and should adhere to the material on which it is placed, and it should also be free from shrinkage cracks due to setting up the material, Magnesite cement appears to fulfill the various conditions outlined above.The elasticity of such cement is the outstanding quality which makes it desirable for exterior work. It also possesses the ability to adhere to all materials in a marked degree. Its freedom from expansion and contraction after setting is one of the principal reasons for its adhesive quality. It may be applied to old brick or stone walls, even tho they have been repeatedly covered with paint, and the quality of adhearing to wood makes it possible to secure a weather-proof protection to the wooden casings and trim of exterior openings. The quality of adhesion and elasticity is easily proved by applying a 1/2"" layer to a 1"" board which has been first covered with metal lath. Such a board, about 8 feet long, may be repeatedly deflected about 3"" in the center without breaking the bond to the board, or causing any cracks to appear in the magnesia cement. The ability to resist fire as well as the possession of insulating qualities are also desirable characteristics of magnesia cement stucco.Magnesite cement stucco should be applied in two coats, each 1/4"" thick on various surfaces such as wood lath, metal lath, sheathing board, brick, hollow tile, or stone; care being taken as regards the presence of lime, unless the same has been rendered, or become inert as with very old, walls. The first coat made up to a consistency that works easily under the trowel is applied in the usual manner. No water should be added to the liquid chloride as it would alter its density, and injure the work. The second or finishing coat is then applied. The aggregates are different in each, and no other dry material should be added to them as they come to the trade. The cement may be applied in zero weather without damage. Setting is quite slow under such conditions, but the cement ultimately becomes hard. It should always be applied to a dry surface excepting that under certain conditions it is desirable to apply a solution of magnesium chloride before using the stucco."

Dec 1, 1919

Provide minx operators with means for evaluating dust generation and bit wear effects on Production without costly and extensive underground testing. Approach Develop personal-computer-based cutting system models that will simultaneously evaluate machine, Coal seam, and mine-operator-controlled parameters for their interactive effects on dust generation, bit wear, and Production by either a longwall shearer or a continuous miner. How It Works CSM Programs have been developed to analyze relative dust generated by a double-drum, ranging arm, longwall shearer and a continuous miner. These interactive programs Provide relative dust, culling forces, and production values for any given set of mining machine parameters, specific seam conditions, and operator-controllable parameters. Expanded versions of each program provide a dynamic evaluation of the effects of bit wear, over time, on production.

Jan 1, 1989

By P. G. Pigott

This investigation by the Bureau of Mines demonstrated that building bricks can be produced by the steam-curing process from various types of industrial mineral wastes. Wastes, utilized to produce bricks, consisted of copper mill tailings, roofing granule fines, asbestos fines, and zinc mill tailings. Bonding of the wastes with either Ca(OH)2 or portland cement resulted in building bricks that met ASTM specification C73-67 for grade SW and MW bricks when evaluated in accordance with ASTM designation C67-66 on sampling and testing of brick. An economic evaluation of the process indicates the total operating cost per 1,000 bricks is about $36.

Jan 1, 1974

By G. W. Murrie, W. P. Diamond, C. M. McCulloch

It is estimated that more than 1 trillion cubic feet of methane is contained within the coals of the Mary Lee group in Jefferson, eastern Tuscaloosa, and southern Walker Counties, Ala. Most of this methane will be encountered by mining. Coals of the Mary Lee group are presently being mined at depths exceeding 1,000 feet and will in the near future be mined at even greater depths, where the problem of methane gas affecting the mining operations will be acute. It is calculated that approximately 90 pct of the methane is at depths greater than 1,000 feet, and over half of the gas is contained within only 12 pct of the study area which is under more than 1,500 feet of over- burden. Degasification in advance of mining will increase mine safety, reduce ventilation expenditures, increase productivity, provide an additional energy source, and make it possible to mine parts of deep coalbeds that probably could not otherwise be mined.

Jan 1, 1976

By Harry Dobroski, Larry G. Stolarczyk

Theoretical and experimental research sponsored by the U.S. Bureau of Mines shows that medium frequency (MF) electromagnetic (EM) signals propagate great distances in an underground environment such as a tunnel or mine. This propagation is enhanced by different mechanisms associated with the geology, and with the existence of metallic conductors in the entryways. In stratified geologies, a transverse electromagnetic (TEM) mode of signal propagation is possible if a low conducting layer is bounded above and below by higher conducting layers. In general, the difference in conductivities must be at least several orders of magnitude. Such geological waveguide conditions often exist in underground mines. Propagation via the waveguide effect is known as the "seam mode" of propagation. Another mode of propagation, the "tunnel mode," exists in underground entries with electrical conductors such as power cables, metal pipes, and phone lines. A monofilar mode of propagation exists when signals are impressed upon conductors and return via the surrounding rock. A bifilar mode of propagation exists when all signals exist only on local conductors. In a given location there is a combination of monofilar and bifilar modes that make possible an interaction between the conductors and a transmitting device in a tunnel or entryway. Signals can be impressed on or received from local conductors via magnetic dipole antennas (loops) or line couplers.