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By Robert L. Virta

This U.S. Bureau of Mines paper discusses the structure of the talc industry, talc production, processing of talc ore, applications and demand for talc, and the outlook for the talc industry.

Jan 1, 1989

By Bernard Baum

Combined preservative/fire retardant systems were pressure impregnated into Douglas fir and Ponderosa pine samples and evaluated for decay, flammability, and mechanical properties. The objective of the evaluation was to identify cost-effective systems for use with mine timber, and to provide an information and data base from which Federal code regulations could be established. Thirty systems, based on combinations of commercially available preservatives and fire retardant impregnants and coatings, were applied to Douglas fir samples and evaluated for decay and flammability. The ten most promising systems were ap¬plied to both fir and pine and reevaluated for decay and flammability before and after water leaching. The five best systems were given a thorough laboratory evaluation using both pine and fir. Evaluations included flame spread, smoke density, toxic gases, decay, compressive strength, flammability after artificial weathering, and cost. All systems had acceptable toxic gas levels and smoke densities, but flame spread was only borderline acceptable for most of the samples tested. A trade-off analysis showed Acid Copper Chromate/Fyrprufe with Albi-107A/144 intumescent paint and Koppers NCX to be the-best systems. Recommendations are made for further large-scale testing using the two best Systems.

Jan 1, 1978

By Robert H. Peters

This U.S. Bureau of Mines report identifies the types of serious accidents that occur most frequently at small underground coal mines and describes the strategies that could help prevent these accidents. A wide variety of methods for improving safety are suggested, including improvements in the design of equipment, work procedures, work schedules, safety programs, and emergency response plans, as well as techniques for diagnosing the potential hazards associated with new technologies and work procedures. Some of the papers in this volume focus on preventing specific types of mining accidents--ones associated with materials handling (primarily back injuries), equipment maintenance, improper machine guarding, and ground failure during retreat mining. Although the recommendations in this volume are heavily influenced by research performed at underground coal mines in the Appalachian coalfields, most of the papers contain advice that is equally pertinent to almost any type of mine.

Jan 1, 1994

By W. H. Young

The thickness of the coal seam is one of the more important items influencing the productivity and general overall efficiency of operation of a coal mine. The average thickness of coal seams mined in the United States has changed very little in the past 40 years. The first measurement of thickness of bituminous coal and lignite seams was made for 1920, when the average thickness was 5.3 feet.4/ The average thickness for later years was as follows: 1945, 5.4 feet; 1950, 5.3 feet; 1955, 5.2 feet; and 1960, 5.5 feet.5/ Table 1 includes data on number and production of bituminous coal and lignite mines classified by I-foot intervals of seam thickness mined in 1920, 1945, 1950, 1955, and 1960. Though bituminous coal and lignite are mined today from seams of exceedingly variable thickness -less than 2 feet to more than 50 feet - a large majority of the production, 62 percent in 1960, came from seams 3 to 6 feet thick. This is not surprising since the coal seam of moderate thickness presents the least mining difficulties.

Jan 1, 1962

By Patricia R. Devine

This appendix documents the mathematical approach to deriving the components of change presented in this report. The formulation closely follows that contained in Chapter IV of the documentation for the BEA 1977 Input-Output Tables.' The basic elements for the calculations include the "use" matrix (U), the "make" matrix (M), and any of the ten columns of final demand (generically represented by the symbol y). The use matrix contains information about changes in the technological processes of production, while the make matrix describes the nature of secondary product production in each industry. We adhere to BEA conventions in maintaining careful distinctions between commodity output (c) and industry output (x). The industry-by-industry 1-0 tables supplied by NYU for use in this analysis are square matrices, with the number of commodities and the number of industries both equal to 85. The BLS table for 1982 (commodity by industry) was aggregated and adjusted to be consistent with the earlier tables. The three basic steps for estimating components of change proceed as follows for each column of final demand. 1) Calculate the actual change in output of each commodity for each of the four time periods: 1963-72, 1972-77, 1977-82, and 1963-82.

Jan 1, 1988

By M. A. Trevits, J. E. Urosek, A. C. Smith, M. P. Valoski

The National Institute for Occupational Safety and Health (NIOSH), in partnership with the Mine Safety and Health Administration (MSHA), is conducting research to test, evaluate, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

By G. Huang, S. Vytla

Computational fluid dynamics (CFD) is a continually developing numerical technique by which complex fluid flow problems can be solved on computers. To be able to transfer CFD expertise to analyze and design a face-ventilation system, a comprehensive validation study of current CFD tools against mining-related benchmark experiments is required. In the last four years, such studies, funded by National In¬stitute for Occupational Safety and Health (NIOSH) under Grant #R01 CCR415822, were conducted in the Department of Mining Engineering at the University of Kentucky. A wide array of ventilation schemes and mining configurations were considered. Recently, an additional study was performed in cooperation with the NIOSH Pittsburgh Research Laboratory. This study was dedicated to the methane behavior in the empty (containing no equipment) face area with a blowing curtain and a 10. 7-m (35-ft) setback. In this paper, the authors present and discuss the computer-simulation data and compare them with data collected during the laboratory studies at the NIOSH lab.

By Meliton M. Garcia

The volume of gases produced in major and trace amounts following the detonation of two water gel and two emulsion explosives in a mine were determined. The volume .of the major gases (CO, CO2, NO, and NO2) was measured immediately following detonation, during the mucking operation, and following the removal of the muck. Tests to identify and quantify the gases produced in trace amounts were performed following the detonation only. The volume of each major gas per pound of explosive (ft /lb) ;ranged as follows: CO, 0.0424-0.3231; CO , 0.6819-1.5632; NO, 0.0129-0.1320; and NO2, 0.0019-0.1111.. An approximate average of 95% of the gases produced was found in the test chamber immediately following the detonation, while less that 2% was found in the chamber following removal of the muck. Benzene was the most significant compound found to occur in trace amounts. Scaling tests performed with a water gel and an emulsion explosive suggest that the volume of the gases per unit mass of explosive detonated diminishes as the amount of explosive per blast increases.

Jan 1, 1986

By Larry Joe Linley

The Department of the Interior, Bureau of Mines is reviewing explosion protection methods for use in gassy coal mines. This performance criteria guideline is an evaluation of three explosion protection methods of machines electrically powered with voltages up to 15 000 volts AC. A sufficient amount of basic research has been accomplished to verify that the explosion-proof and pressurized enclosure methods can provide adequate explosion protection with the present state of the art up to 15 000 volts AC. The routine application of the potted enclosure as a stand alone protection method requires further investigation or development in order to clarify performance criteria and verification-certification requirements. An extensive literature search, a series of high voltage tests, and a design evaluation of the three explosion protection methods performed at White Sands Test Facility indicates that the explosion-proof, pressurized, and potted enclosures can all be used to enclose up to 15 000 volts AC, if the performance criteria and verification-certification requirements recommended in this guideline are implemented.

Jan 1, 1982

By Kenneth Eilerts

[Efficient and econonic production of ?etroleum requiros knowledge of the propertios of rescrvoir fluids a:$. their characterintics of flow throayh porous forclntions. The cllanga in propertie s and flow characteri s- tics of fluids when their corosition is altercd cs a rnsult of reservoir- pressure decliae is of 'mecial i~ortenct? ir, planning wall-spaAng pro.yama and production schedules. Rct~ntion of the ~eatent poscible quantity of dissolved gac in the rescrvoir liquid gnneml'y is recognized cs ess~ntisl to mxim ultimzte recoverj of oil fro3 the underground reecrvoir. Ilo:rever, pro6uction mothodn tending to mintain gis in solution in the oil and re- sulting in the optimm ocolo~ic recgvery of oil not only vary from field to fiold but also my have to be changed from time to time in a given field as it is being depleted of its recoveraklo oil. Const vestly there is need tc investigztc tY.e propertiec of resa:-voir f kids corresponding to successivc stages of reservoir depleJ&ion with the view of obtnining infomation oacential to efficient prcriuctian practices.]

Jan 1, 1939

By J. C. Duchon

The U.S. Bureau of Mines is conducting human factors research for the purpose of reducing accidents and improving the person-machine interface found in surface and underground mining operations. Miners are exposed to a variety of environmental stressors, e.g., extreme heat, noise, vibration, and adverse illumination, throughout the workday. Exposure to these environmental stressors has been noted in the literature to affect performance on vigilance tasks. Since impaired performance at vigilance tasks can lead to industrial accidents, further investigation of the effects of environmental stressors on human performance is warranted. A brief description of the environmental conditions present in the mining workplace is followed by a review of experiments dealing with the effects of environmental stressors on vigilance task performance. The applicability of past research to actual mining operations is considered.

Jan 1, 1989

By D. T. Holmes, W. G. Sandell

"INTRODUCTION Three representative lots of ore wore obtained from the Aguila minim district in Arizona during the Bureau's exploration of manganese deposits there. Since only selectively mined ore from this district will meet commercial-grade specifications, the ores were studied to determine their amenability to concentration.Although the purpose of the investigation was to determine the possibilities of the district as a source of commercial-grade manganese, testing was sufficiently comprehensive to indicate the response of the ores to several different types of treatment. Many data of secondary importance have been omitted, end only the more pertinent tests are presented in detail.At the beginning of the investigation of manganese-ore beneficiation in December 1940, the only product marketable to. Metals Reserve Company was ferro-grade manganese, grade B, the requirements for which follow: Mn, min., 48 percent; Fe, max., 7 percent; Si02, max., 10 percent; P, max., O.18 percent; Al12O3, max., 6 percent; Zn, max., 1 percent.Later the specifications were modified gradually. As of May 15, 1943, manganese products were acceptable if they contained over 35 percent manganese and less than 3 percent zinc and 1 percent phosphorus. Prices were based upon material containing 48 percent manganese, 6.O percent iron, and. 11 percent silica plus alumina. Premiums were paid for manganese con¬tent over 48 percent and iron content under 6 percent, penalties being imposed upon products containing loss than 48 percent manganese or more than 6 percent iron or more than U. percent. silica plus alumina.. The specifications for commercial manganese further required that the maximum particle size be 12 inches and that 75 percent of the product be coarser than 20-mesh. Therefore, fine material, such as table and flotation concentrates, had to be nodulized or sintered. In addition, carbonate manganese ores were not acceptable unless calcined.."

Aug 1, 1948

By D. P. Schlick

As of June 30, 1970, Federal regulations required the operator of each underground coal mine to maintain the average concentration of respirable dust below legislative standards. As of March 1, 1971, over 152,000 respirable dust samples have been processed by the Bureau of Mines. Approximately 75 percent of underground working sections are being sampled in accordance with Federal regulations. Results indicate that 72 percent of the sections which have completed at least one basic sampling cycle are below 3.0 mg/m3, the standard in effect under the Federal Coal Mine Health and Safety Act of 1969 (P.L. 91-173). Notices of Violation were issued on 1,670 underground mines for failure to begin a sampling program; Withdrawal Orders were issued in 64 of these instances. Notices of Violation were issued on 1,121 sections where applicable dust levels were exceeded; Withdrawal Orders were issued in seven of these instances. There are 381 mining sections currently operating on permit; from the interim Compliance Panel.

Jan 1, 1971

To improve a miner's chances for survival in an emergency by providing an improved self-rescuer device that functions in a toxic or oxygen-deficient atmosphere. The Approach: Development of a compact, lightweight apparatus which produces oxygen by using the wearer's breath in a chemical reaction. How It Works: The device is designed to cause the user's breath, which contains water vapor and carbon dioxide, to react with potassium superoxide (K02) to produce oxygen in quantities sufficient to sustain the wearer for one hour. The system is a closed circuit and does not depend on "screening" of noxious gases. To use the device, the miner opens the top and

Jan 1, 1974

By R. B. Ladoo

"Present Situation:At the beginning of 1920 a general feeling of optimism was noted in many talc-producing districts. The industry seems to have recovered from the temporary depression of the first half of 1919 and many mills are running at capacity production with their entire output for 1920 contracted for. The imports of talc for 1919 were only slightly larger than in 1918 by weight and probably no more by value. Thus foreign competition has not begun to be seriously felt. Several new companies in this country have been organized, some to operate new deposits and others to continue the work done by others.An interesting phase of the present situation is the possibility of increased use of talc in paint. There is a shortage of barium sulfate used as a paint filler. Since, for some uses, talc is considered second only to BaSo4 as a filler for paint, it is possible that part of the shortage could be relieved by an increased use of talc.A series of physical tests upon all pigment materials used in the manufacture of paints is being conducted for the Paint Manufacturers Association of the United States. It is important that all types of talc be represented in these tests. Producers of finely ground talc, 200 mesh and finer, are urged to submit samples of at least two pounds each of these grades that are available to paint makers with trade name and quality data, to the Institute of Industrial Research, 19th & B Streets, N. W., Washington, D. C., where the tests are being conducted."

Jan 1, 1920

This publication summarizes, for potential contractors and other interested parties, the research, development, and demonstration contract projects programed by the Bureau of Mines for fiscal year 1979 (October 1, 1978-September 30, 1979) under its Mine Health and Safety Research program. The objective of these projects is to provide an ordered and sequenced series of advances toward the Bureau's overall goal of providing the system technology required to create a healthier and safer working environment for the Nation's miners.

Jan 1, 1979

By David E. Siskind

The U.S. Bureau of Mines and the State of Indiana cooperated with AMAX Coal Co. and its consultants to determine the effects of coal mine overburden blasting on nearby pipelines. Five pressurized 76-m pipeline sections were installed on the Minnehaha Mine highwall near Sullivan, IN, for testing to failure. Four 17-to 51-cm-diameter welded steel pipes and one 22-cm PVC pipe were monitored for vibration, strain, and pressure for a period of 6 months while production blasting advanced up to the test pipeline field. In contrast to previous studies of small-scale, close-in blasting for construction, these tests involved overburden blasts of up to 950 kg per delay in 31-cm blastholes. Analyses found low pipe responses, strains, and calculated stresses from even large blasts. Ground vibrations of 120 to 250 mm/s produced worst case strains that were about 25 pct of the strains resulting from normal pipeline operations and calculated stresses of only about 10 to 18 pct of the ultimate tensile strength. No pressurization failures or permanent strains occurred even at vibration amplitudes of 600 mm/s.

Jan 1, 2010

By R. A. Cummings

Certain roof shales in coal mines deteriorate upon exposure to the atmosphere, causing difficulties in the mining operations and adding to the cost. This report presents the results of both field investigations, in a West Virginia mine, and laboratory studies on the effects of atmospheric moisture on roof shales. Based on these observations, a conceptual procedure is presented on how shale deterioration might be predicted during exploration, and guidelines are given as to how air tempering or conditioning chambers may be designed to reduce moisture effects. Recommendations for further studies are included. An annotated bibliography of the literature constitutes the second volume.

Jan 1, 1981

By William C. Cooley

This report includes a review of all relevant data on underground hydraulic coal mining technology collected during Phases I and II of the contract. Data collection and analysis procedures are discussed. Information is included on past and existing underground hydraulic coal nines in the USSR (27 mines), Poland (1 mina), Germany (1 mine), Japan (1 mine), Canada (1 mine), China (1 nine), as well as underground tests conducted in the United Kingdom (2 mines), and in the United States (5 mines). Data is also included on Czechoslovakia and New Zealand. In all operational hydraulic mines, coal is transported underground in flumes. In most cases, bituminous coal is broken by monitors with nozzle diameters larger than 16 mm (0.63 in.) and jet pressures of 50 to 125 atm (710 to 1780 psi). Technical design and performance data are included on all key types of equipment and components which have been developed for, used in, or which could be potentially be used in hydraulic coal mining systems. Data sheets are presented on 180 types of equipment, divided into 24 major categories. Where available, sketches, drawings, photographs, and price estimates are included. Data are included on pitching coal seams in the United States which potentially can be mined by hydraulic methods. Preliminary conclusions are presented, subject to revision as a result of economic feasibility studies to be completed during Phase III. An outline is presented of the final report, which will include economic studies and recommendations for research and development.

Jan 1, 1975

By R. Marshall

Electrical trailing cable handling techniques and practices used in metal and non-metal surface mines were investigated by obtaining information through actual visits to the mine properties located in a variety of geological areas and climatic conditions. An analysis was made of all accidents related to cable handling which are cataloged by HSAC* for the period from 1971, through June 1980. Information was also collected from mine operators concerning near accidents and non-reported accidents. The results of this investigation were presented to the U.S. Bureau of Mines in an effort to outline recommended practices for cable handling in surface mines and to recommend additions and/or changes in the present regulations now being enforced by MSHA** field inspectors. These recommendations are also intended to assist the U.S. Bureau of Mines in evaluating the need for assisting the mine operators in the areas of training and distribution of information related to material handling of trailing cable. * Health Safety Analysis Center ** Mine Safety & Health Administration

Jan 1, 1980