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By Wadaw Cybulski

The problem of coal dust explosions: Basic information about the explicability of coal dust: Main parameters of the explosibility of coal dust; Main parameters of the explosibility of coal dust; Limit explosibility of coal dust and its dependence upon the basic parameters: The effect of the initiator of the explosion-on-the explosibility of coal dust: The dependence of the course of an explosion upon the distribution of coal dust in the workings, upon the dimensions of the workings, the length of zones, the direction of the development of explosions and upon the content of firedamp in the air of the workings; Con-sequences of coal dust explosions; The ways of suppressing the danger of coal dust explosions; Stopping the developed coal dust explosions; The explosibility and explosions of lignite dust of xylite structure

Jan 1, 1975

By Olman Hee

This study investigates the identity and relative importance of factors affecting the future demand for phosphate rock, potash, and nitrogen. The main objective is to analyze demand relationships for these chemical raw materials for some specified past period, and to utilize this information to make projections of consumption into some designated future period. The end-use approach is used, which divides total consumption of each chemical raw material into agricultural, industrial, and export use. Multiple regression analysis is employed to statistically measure the relative effects of the different factors on consumption in each end use. The general method centers on the construction of a consumer demand model, the fitting of the respective equations in the model, and the interpretation of the statistical results. Direct and cross price elasticities of demand are computed for each end use of the chemical raw materials. These give an insight into expected changes in consumption with respect to given changes in price. The results of this study indicate that price, consumer income, and level of technology are factors which measurably affect consumption of chemical raw materials. For phosphate rock and potash, the agricultural and industrial end uses showed an inelastic demand, whereas for nitrogen, all end uses (including export use) exhibited an elastic demand. Among the chemical raw materials, average annual growth of consumption of nitrogen for agricultural and export uses to 1980 is expected to be notably higher than that for phosphate rock and potash.

Jan 1, 1969

Fossil fuel consumption in the United States increased markedly over recent years, and future demands expect to be even greater. Coal, this Nation's most plentiful natural fossil fuel, will play a key role in fulfilling these demands. With expectations of increased coal exploitation, the U. S. Bureau of Mines authorized this project, the objectives of whi.ch were to prepare an authoritative report on current surface coal mining technology, to define current problems and possible solutions, and to project future developments necessary to assure adequate surfaced mined coal production to meet the Nation's future energy needs. These objectives we're accomplished by an extensive review of available published literature and data gathering field visits to active surface coal mines throughout the country.

Jan 1, 1975

By Alvin Schallis

The. problem of supplying enough magnesia for the American war effort has become highly important. Before hostilities began, only about two-thirds of our, require vents came from domestic sources; now they must supply almost all the magnesia we need. A further burden is placed upon our own supply by the fact that more and more magnesia is being required, not alone to pace the war tempo of general industrial activity, but also to replace chrome ore in refractories and to make magnesium metal. The domestic magnesite and brucite industry is equipping itself to satisfy much of this greater demand for magnesia, but the remainder must be obtained elsewhere. The principal sources of magnesia are magnesite, brucite, dolomite or high-magnesium limestone, natural brines, sea water, salt-works bitterns, magnesium silicates, and magnesium salts. Although dolomite is tae subject of this paper, it should be considered in perspective with all these highly competitive sources of magnesia.

Jan 1, 1943

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in an operating coal mine, Robena No.4, located near Waynesburg, Pennsylvania. One technique measures noise over the entire electromagnetic spectrum of interest for brief time periods. With present instrumentation, the spectrum can be covered from 40 Hz to 400 kHz. It is recorded using broad-band analog magnetic tape, and the noise data are later transformed to give spectral plots. The other technique records noise envelopes at several discrete frequencies for a sufficient amount of tine to provide amplitude probability distributions. The specific measured results are given in a number of spectral plots and amplitude probability distribution plots. The general results are that at frequencies below 10 kHz, power line noise within the mine is severe. Impulsive noise is severe near arcing trolleys, and at lower frequencies near any transmission line. Carrier trolley phone signals and harmonics are strong throughout the mine whenever the trolley phone is in operation. Additional information beyond that included in this report may be obtained from the authors, who are with the Electromagnetics Division of the National Bureau of Standards.

Jan 1, 1974

Research 83 highlights significant studies conducted during the past fiscal year at Bureau facilities and offices. Readers who want more information about the projects and studies summarized here can contact the researchers whose names and locations appear with each summary, General information on Bureau of Mines programs is available from the Office of Technical Information, 2401 E Street, NW., Washington, DC 20241. A listing of principal officials, a location map of field facilities, and a selected bibliography of publications and patents issued on Bureau developments during the past 3 years are provided.

Jan 1, 1983

By W. R. Hardwick

This Information Circular describes copper mining and concentrating methods, practices, and costs at the Silver Bell Unit of American Smelting and Refining Co., Pima County, Ariz. It is one of a series being prepared by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. The Silver Bell mining district, one of the older districts in Arizona, is in the western part of the Silver Bell Mountains in Pima County, about 40 miles west of Tucson and about 20 miles southwest of Red Rock, a station on the main line railroad of the Southern Pacific Co. The Oxide and the El Tiro open-pit mines of the American Smelting and Refining Co. are in the district (fig. 1. The principal ore deposits are in T. 12S., R.8E., Gila and Salt River base line, at an altitude of about 3,000 feet. The present town of Silver Bell, established in 1952, is reached by a paved highway, the Avra Valley road, that turns west from Highway 84 at Plata siding near Rillito and extends westward 25 miles to the townsite (fig. 2). The present town is about 5 miles southeast of the old town of Silver Bell that flourished from 1900 to 1930.

Jan 1, 1963

By W. R. Hardwick

This Information Circular describes copper mining and concentrating methods, practices, and costs at the Silver Bell Unit of American Smelting and Refining Co., Pima County, Ariz. It is one of a series being prepared by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. The Silver Bell mining district, one of the older districts in Arizona, is in the western part of the Silver Bell Mountains in Pima County, about 40 miles west of Tucson and about 20 miles southwest of Red Rock, a station on the main line railroad of the Southern Pacific Co. The Oxide and the El Tiro open-pit mines of the American Smelting and Refining Co. are in the district (fig. 1. The principal ore deposits are in T. 12S., R.8E., Gila and Salt River base line, at an altitude of about 3,000 feet. The present town of Silver Bell, established in 1952, is reached by a paved highway, the Avra Valley road, that turns west from Highway 84 at Plata siding near Rillito and extends westward 25 miles to the townsite (fig. 2). The present town is about 5 miles southeast of the old town of Silver Bell that flourished from 1900 to 1930.

Jan 1, 1963

By S. S. Venkata

This volume describes a comprehensive program of research into the reliability of mine electrical power system components and the resultant reliability of the total system. The research effort encompassed analytical models, laboratory testing and field testing. The analytical work included definition of terms, fail rate functions and distributions, failure rate estimation and techniques and procedures for theoretical reliability assessment. One of the primary mine power system components addressed in the study was the ac molded case circuit breaker. This device is known to have low reliability and hence an unfavorable impact on mine safety and productivity. Ac molded case circuit breaker reliability was studied by analytical means, laboratory testing and field monitoring. A similar three-pronged' effort was made to study the reliability of undervoltage relays/releases. Particular emphasis was placed on new solid state undervoltage relays. The reliability of bulk power components, such as trailing cab les, motors, control gear, and other equipment, was assessed by gathering maintenance records from active mines. These data were compared to similar records from other industries. The work was extended to include the reliability, availability, maintainability and safety of these components.

Jan 1, 1979

By G. F. Kuncir

This volume was prepared in support of an evaluation of the Advancing Oil Shale Mining Technology Program performed by The Aerospace Corporation under a Bureau of Mines contract. The evaluation is described in part within a companion volume entitled Benefit-Cost Analysis. The economic mine models outlined herein provide a quantitative basis for the assessment of program benefits. Reference is made to estimated oil shale mine costs to delineate the beneficial impacts that can be expected to accrue for the future implementation of program developed technology. Estimated mine cost data are provided for surface, underground, and modified in situ oil shale mining operations.

Jan 1, 1977

By Shelby Z. Palya

"INTRODUCTION The Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment, and utilization of mining substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable. This issue describes reports and articles published during the period January 1, 1975, to December 31, 1979. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960; 2 the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960; 3 the 5-year lists of publicatioll3 and articles, from January 1, 1960, to December 31, 1964,4 from January 1, 1965, to December 31, 1969,5 and from January 1, 1970, to December 31, 1974; 6 and the annual lists of Bureau publications and articles from January 1 to December 31, 1975,7 from January 1 to December 31, 1976,8 from January 1 to December 31, 1977,9 and from January 1 to December 31, 1978.10"

Jan 1, 1980

By A. C. Fieldner

This report is the fourth of a series of annual summaries of research and technologic work on coal by the Technologic Branch of the Bureau of Mines. The coal research program of the Bureau has been broadened and made more flexible to adapt it to changing conditions and needs of the coal industry, and as a result information as to the properties and composition of coal has been increased and new and improved practices in mining, preparation, and utilization of coal have been devised. The present

Jan 1, 1940

By Robert C. Weisner

Current production costs and market conditions in the potash industry of the Carlsbad area were studied to determine the potential values of the potash mineral resource that would be lost or foregone if the Waste Isolation Pilot Plant (WIPP) facility is constructed on the proposed site in that area. The purpose of the WIPP project is to investigate the possibility of developing a nuclear waste disposal plant in the salt formations at the site. Analyses were made of all potash deposits determined to be in the site. Mining and processing under the most favorable recovery systems were considered. Value determinations were based upon estimated operating and capital costs of current mine-mill operations in the Carlsbad area. This study was made for the Energy Research and Development Administration (ERDA) by members of the Federal Bureau of Mines Minerals Availability System staff.

Jan 1, 1979

By W. T. Abel

The difficulties associated with wet-processing fine size coal led the Bureau of Mines to investigate a dry process for removing pyrite from coal pulverized to powerplant fineness. The dry process that was investigated consists of two cleaning steps: First, centrifugal separation is used to remove a fine, pyrite-depleted portion as a product; second, the remaining coarser, pyrite-enriched portion is taken to electrostatic separation in which pyrite is concentrated and rejected. Ball milling and Hardgrove milling were used to pulverize the coal. Three coals from the Pittsburgh seam were treated by the dry-removal process. Over 55 pct of the pyrite, which amounted to 70 pct of the available pyrite, was removed in a reject of 10 to 20 pct from one of the coals. Similar treatment of the other two coals removed about 35 to 50 pct of the pyritic sulfur, which amounted to about 70 pct of the available pyritie, sulfur from these coals. Both centrifugal and electrostatic separations were more efficient when pyrite particles were as large as possible. Separation efficiency was improved by confining the particle size of the feed to a relatively narrow range and by avoiding excessive amounts (more than 10 pct) of dust in the electrostatic range. The removal efficiency was increased with the use of stage grinding.

Jan 1, 1973

The Minerals Data Source Directory is a compilation of descriptive information on the availability, content, and location of minerals data in the Federal Government. It is intended to assist Government personnel and the general public in locating and acquiring minerals information. Included in the Directory are descriptions of data bases, publications, information systems, and information offices containing data pertaining to ail aspects of mineral production, consumption, trade, and related information. These mineral data sources include the Federal agencies such as the Department of the Interior's Bureau of Mines and Geological Survey whose major mission is the collection and dissemination of mineral information. Also included are agencies such as the Departments of Agriculture, Commerce, Labor, State, Transportation, and Treasury, the Central Intelligence Agency, the Environ- mental Protection Agency, the Federal Reserve System, the interstate Commerce Commission, and the Securities and Exchange Commission, whose primary mission is the collection of data in nonmineral subject areas, but in which the mineral industry is a component.

Jan 1, 1983

By Fraser M. Walsh

The objective of this program was to determine by laboratory experiments the kinetics and mechanics of the reactions that produce acid in coal mine drainage. The program was divided into three phases: In Phase I, five coil mines, representative of Appalachian coal mines, were chosen for sampling and an experimental design was identified suited to accomplish the program objectives. In Phase II, the five mines were sampled and test protocols applied. The results showed most pyrite weathering to be based on oxidation in the presence of water. Iron bacteria, especially Thiobacillus ferrooxidans, catalyzed the rate of pyrite weathering by a factor of three. An increase in initial iron concentration in a system that modeled the nine environment acted to inhibit bacterial catalysis of weathering. In Phase III, five tailings piles were sampled and the material obtained was used to evaluate this method of bacterial catalysis inhibition. The evaluation verified method effectiveness; inhibition of over 80% of the release of weathering products was observed.

Jan 1, 1982

By James N. Bayne

An examination and analysis of Landsat digital data in the monitoring of surface mines in selected counties of South Carolina.

Jan 1, 1979

By J. J. S. Sebastian

The process development described in this report was carried out at the Morgantown Station of the U. S. Bureau of Mines in cooperation with West Virginia University. An experimental laboratory-scale pilot unit to gasify coal dust in entrainment was constructed on the Campus of the University in Morgantown. The enormously accelerated demand for liquid and gaseous fuels and utilization of our immense coal resources require that a low-cost process be developed for the gasification of a wide variety of coals. Such a process would be a major factor in lowering the cost of synthetic liquid fuels. None of the proc3sses developed in Germany prior to and during World War II, such as the Winkler process, the H. Koppers dust gasification process, the Wintershall-Schmalfoldt process, etc., meet all the requirements for a low-cost process under American conditions. Nor has any other process designed and experimentally operated at atmospheric pressure during the post-war period in this country appeared to fulfill all of the necessary conditions for a low-cost process.

Jan 1, 1950

By Paul S. Goodman

This report examines the effectiveness of bonus plans in the coal industry. The analysis uses theoretical, literature review and empirical approaches to determine the impact of bonus plans on safety and productivity in underground coal mines. The basic finding is that the modal bonus plan in underground coal mining does not have a major impact on productivity and safety indicators. The design of the plan, or organizational factors, and the process of introducing the plan all contribute to its relative ineffectiveness. Strategies and options for designing effective plans are presented.

Jan 1, 1987

By Clayton R. Morlock

Airblasts have been monitored at four coal strip mines and at a limestone quarry. Thirty-seven production blasts have been monitored with three seismographs, resulting in one hundred and eleven complete air pressure records. Instrumentation selection use is described. Data analysis includes an assessment of the predictability of peak overpressures by means of the cube root scaled distance law. It is found that predictability for the cases studied here is not good. An extensive discussion of possible explanations is included. A detailed analysis of the frequency content of the observed airblasts, of considerable importance in evaluating potential annoyance problems, has been made for all records. A computer program has been written to simulate airblasts induced by multiple-hole blasts. A series of small experimental blasts have been detonated and monitored in order to allow an assessment of the program. It is clear that airblasts, especially when induced by very small charges and monitored at very close distances, are highly sensitive to detonation times. Retrofitting of airblast records occasionally was possible, but considerably improved field work is required to validate or refute the computer model.

Jan 1, 1983