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By Anthony Iannacchione, Christopher Mark

Residents of Maxwell Hill, a suburb of Beckley, West Virginia, reported from January until March of 1988 a series of earth tremors. The tremors rattled dishes, and the noises associated with tremors were sometimes loud enough to wake people at night. These events were puzzling because Beckley is in an area of low seismic activity. Maxwell Hill is located above abandoned coal mines, though no direct subsidence damage to surface structures has been documented. A research program was initiated to determine whether subsurface ground movements associated with the abandoned mines could be responsible for the seismic activity experienced at the surface. A hypothesis is proposed which states that seismic disturbances can be caused by abandoned mine failure when two conditions are met. First, some instability must exist at the mine level. The most likely cause of instability is the failure of pillars of coal that were left for support at the time of mining. Second, subsurface movements can result in significant seismic activity only when the rock above the mine contains at least one very strong and brittle layer that is prone to fail violently through rupture or fault slip movement. Analysis of the data indicates that both hypothesized conditions for mine-related seismicity appear to have been satisfied in the case of Maxwell Hill. It has therefore been concluded that the earth tremors experienced by Maxwell Hill residents probably are related to the abandoned mines. Analysis of the potential magnitude of these events indicates that they are unlikely to cause significant surface danlage. The probability that future events will disturb the residence of Maxwell Hill should be quite low based on the identified mechanism.

By Louis P. Domingues

As part of a study on high-temperature ceramic materials, the ammonium sulfate, carbonate, nitrate, oxalate, and sulfate salts of yttrium, lanthanum, and cerium were analyzed thermogravimetrically. The temperature ranged from room temperature to 1,500° C. Each salt was decomposed by heating at a rate of 2.5° C. per minute, and some of the salts were subjected to additional rates of 5° C. per minute or 10° C. per minute. The decomposition sequences have been identified, and the temperatures of formation of intermediate compounds and of the oxides have been determined. The minimum oxide formation temperature of a given lanthanum salt exceeds that for the similar salt of yttrium, and both exceed that for the same salt of cerium except for one cerium carbonate. Variation of the heating rate indicates a thermal lag in the materials and produces the shift of formation temperatures to higher values and loss of resolution in the weight-loss distribution as the heating rate increases.

Jan 1, 1962

By E. V. Deshayes, W. E. Young

"INTRODUCTION The Camp Bird mine was investigated by Bureau of Mines engineers 3/ September 22 and 24, 1942, and April 29 and 30, 1944. In a subsequent report and supplement, it was recommended that core drilling be done below the 14th. level to determine if commercial ore existed at greater depths, and particularly if ore existed in the vein or adjacent thereto where it passes into the sedimentary formations estimated to underlie the volcanics approximately 400 feet below the 14th level.Seven diamond-drill holes aggregating 3,956 feet were drilled. Four of these holes were under the Hematite ore body and three were under the Big Discovery ore body. Two holes under, the Hematite ore body wore directed at angles but little steeper than the angle of dip of the vein and penetrated the sedimentaries beneath the volcanics close to the vein. Enough low-grade ore was found at the base of the Telluride conglomerate to indicate the presence of a large body of low-grade zinc sulfide ore. Two holes were directed to crosscut the vein at a depth of approximately 125 feet below the 14th level. No commercial ore was cut, but the vein showed the average width and same general characteristics as at the 14th level. One hole under the Big Discovery ore body was directed to crosscut the vein and test the base of the Telluride conglomerate in the footwall block. No commercial ore was found in either the vein or the sedimentary horizon. One hole was directed to test the base of the Telluride conglomerate in close proximity to the vein in the hanging-wall block. This hole was lost approximately 100 feet short of its objective, and a third hole was drilled to accomplish this same thing. The third hole was stopped approximately 50 feet short of its objective when failure of equipment caused a recess of the"

May 1, 1948

By Richard G. Geyer

One aspect of a program to improve the chances of survival following coal mine disasters is the development of a communications sys tem which will allow surviving miners to make their circumstances known to rescue teams. At present, it appears that an electromagnetic system may be most practical. The development and design of an effective electromagnetic communications link for signalling between mine workings and the surface requires knowledge of pertinent physical properties of the rocks overlying the mine workings and the characteristics of the ambient noise against which a communications signal must be recognized. Knowledge of the overburden electrical transmission properties is useful not only for determining a practical operating transmitter frequency at a given mine, but also for ensuring the best possible electromagnetic coupling for routine or emergency communication purposes. Field studies of the electrical transmission properties of the overburden of coal mines in Colorado, Illinois, and Pennsylvania generally show that a relatively uniform and unimodal electrical conductivity distribution exists provided that the region has not been subject to considerable structural or metamorphic deformation such as that observed in the Gary District of West Virginia. Measurement s of ambient surf ace electromagnetic noise levels at several mines in Colorado, Illinois, and West Virginia were taken and analyzed and are presented in the form of amplitude histogram plots both as a function of frequency and time of day. These amplitude histograms may be used in conjunction with overburden resistivity data in implementing an uplink communications beacon system which will yield a specified signal- to-noise ratio at the surf ace. Numerous C .W. field transmission tests were made in various coal mining environments with use made of either a buried vertical-axis transmitting loop or a short insulated grounded current line. These transmission tests were made from 20 Hz to 20,000 Hz in frequency and at several geographic surface receiving sites. The results of these field measurements show, in general, good agreement with theoretically calculated results. Since the produced surf ace magnetic field from a buried vertical-axis loop source or the produced surface horizontal electric field from a buried horizontal current line show better agreement with theoretical results, they could be used for beacon location system. One criterion would be in detecting the equatorial and polar null lines of the horizontal electric field component which is normal to the direction of emplacement of a buried transmitting line current source. A second criterion would be in the surface mapping of the maximum in the vertical magnetic field directly over a vertical-axis loop transmitter and the associated null is the vertical magnetic field at a horizontal offset distance which is about 1.4 times the depth of burial of the transmitter. Finally, a third criterion would lie in the surface mapping of the null in the horizontal magnetic field directly over the vertical-axis beacon and the associated maximum in the horizontal magnetic field at an offset distance from the transmitter axis of half the depth of burial of the loop transmitter. In mapping the vertical magnetic field over a buried vertical-axis loop transmitter, the size effect of the transmitter loop must be taken Into account when the separation distances between the transmitter and receiving sensor are less than ten times the effective radius of the source loop; increasing the size of the transmitting source relative to the source-receiver separation distance shifts the null in the vertical magnetic field to greater offsets. In mapping either the vertical or horizontal magnetic field over a buried vertical-axis loop transmitter, care should be exercised in ascertaining that measured nulls and maxima are along radials through the axis of the buried source loop. For the main part, coupling experiments show that ambient electromagnetic noise in coal mining districts is less of a problem above 1000 Hertz. But secondary and perhaps undesirable maxima and null phenomena (as well as penetration problems) would occur in many coal mine provinces in the behavior of the surface horizontal magnetic field (over a buried vertical-axis loop transmitter) if transmission frequencies as high as 10 kHertz were used.

Jan 1, 1974

By Jack Wasserman, Don Wasserman, Logan Mullinix, Shekhar Khanal, Kelly Neal

This paper presents current finding on truck driver average exposure to acceleration for several different manufacturer’s cab-over trucks on a variety of roads in different countries. The predominant time, for this aspect of the study has been spent in the area around London, England and Warsaw, Poland. The ECE directive 2002/44/EC has provided specific guidelines for vehicle operators 8 hour average acceleration exposure. The primary considerations have been on truck design including the air-ride driver’s seat. The truck manufacturers have produced truck cabs that have some separate suspension from the truck frame. The truck seat manufacturers have been producing air-ride suspension seats for the cab. Both of these designs have had the objective of meeting the ECE directive and providing the vehicle drivers with some degrees of comfort. This paper will provide some information on the ability of the vehicles to operate on a variety of roads and meet the objectives. Method The primary method for evaluation of the driver’s exposure has been the use of a seat pad attached to the driver’s seat. Although this sensor system provides the critical information for the driver, an understanding of the reasons for the values requires additional measurements. The initial study in England used both driver and passenger seat pads, as shown in Figure 1, as well as triaxial accelerometers mounted on the base of the seat. The latest studies used significantly more transducers to better understand the relative rotations and translations on the truck frame, the cab, and the driver. [ ]

Jan 6, 2006

By W. R. Hardwick

This information circular describes open-pit mining methods and practices of the Bagdad Copper Corp., Yavapai County, Ariz. It is one of a series being prepared by the Federal Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. A brief history of the Eureka district and of early developments at the [gdad] mine is given, and the are deposit is described with particular emphasis on those characteristics (physical, economic, or engineering) that affected the choice of mining methods. Prospecting, exploration, and sampling and estimating the tonnage and grade are outlined. Development of the open-pit mine is shown. Mining methods, including breaking ground, primary drilling and blasting, secondary drilling and blasting, loading, transportation, engineering, and operating control, are described. A brief summary of mining equipment is given. Percentage of extraction, production rate, mine drainage and water supply, wage, contract, and bonus systems, safety and fire prevention, and the processing plant also are described. The last section gives a breakdown of such costs as are available for publication.

Jan 1, 1959

By William M. Knuth

This study involved a review of bonding and bond release practices in the states of the Eastern and Midwestern Coal Provinces. Data was collected from regulatory authorities and site visits to document the bonding and release procedures in the states related to achieving successful reclamation. The regulations related to PL95-87 were reviewed. The analysis included suggested modified or new bond release criteria, a review of applicable bond release inspection techniques was prepared, a conceptual graduated bonding system and incentive procedures for reclamation of surface mine sites to alternative or higher land uses. A number of conclusions and recommendations for further research were included. A detailed bibliography and a glossary are included in the report.

Jan 1, 1978

The annual reports of the supervising engineer of the seven sections comprising the Mining Division are assembled in the following pages and form the annual report of the division. In planning activities, the aim has been to adapt the work to changing conditions and needs of the mining industries and to avoid becoming bound to any particular type of investigation when others are found to be of more pressing interest.

Jan 1, 1939

By Paul Hatmaker

"The Bureau of Mines recently has issued a general information circular covering briefly the origin and occurrence, properties, uses, exploitation, and marketing of diatomite. Since this publication was prepared, additional information has become available regarding one of the newer uses of diatomite — that as a filler in battery boxes. As this market is rapidly becoming one of the important outlets, a brief discussion of such use may be of interest.Diatomite is a mineral substance composed principally of the skeletal remains of diatoms. The skeletons of these microscopic flowerless water plants are made from silica present in the water in which these tiny plants live. The minute shells or ""casts"" accumu¬late in the bottom of lakes, ponds, or inland seas, and eventually become more or less consolidated into beds of diatomite.The uses of diatomite depend largely upon its peculiar properties. Diatomite is a highly porous substance and possesses marked absorptive powers. The large percentage of pore space makes the material very light in weight. It is relatively insoluble in most solutions.The largest deposits in the world are found in California, but diatomite occurs in many other Western States and also is found in a number of places along the Atlantic seaboard. Outside of the United States diatomite occurs in many countries; Algeria and Germany are among the largest producers.Usually diatomite is mined either by underground or open—cut methods. In some instances it may be dredged from lake and swamp bottoms. It must be dried prior to grinding or other preparation for market, and for many purposes must undergo a complex sizing and grading system for removal of such impurities as sand and clay and for classification of the material to the various sizes desired,"

Mar 1, 1931

The compliance sampling method for coal mine dust in the United States has not changed appreciably in the last 30 years. A call for more frequent sampling with immediately available results is leading to new instruments that may supplement or replace the existing sampler. This report discusses two such instruments that provide immediate results of dust levels. The first, called the Respirable Dust Dosimeter (RDD), is designed to supplement the existing U. S. cyclone compliance sampling method. It uses the pressure drop across a filter to provide an inexpensive screening type of measurement. The RDD has been tested in the laboratory and a limited number of coal mines. Side by side testing has compared the RDD performance with personal coal mine samplers in triplicate area sample measurements. Results show that the differential pressure of specific filtration media can be an effective surrogate for respirable mass. Data show that there is a dependence on coal type and an effect of relative humidity. There also appear to be two distinct responses related to coal type. For specific coals the coefficients of determination, R2, are better than 0.9. For general use the detector tube, using laboratory generated calibration curves, can be used to estimate respirable dust levels. However, a calibration to a specific coal type may substantially improve the accuracy. Another sampler in development is called the Personal Dust Monitor (PDM). Designed to give compliance quality accuracy, the PDM uses the frequency change of a vibrating element to measure dust and give immediate feedback of results. Results of laboratory comparison of the prototype PDM sampler to personal gravimetric samplers indicate R2 values of better than 0.99 for three different coal types. Work is in progress to package the components into a person-wearable unit combined with a cap lamp system with a total projected weight of less than 1.4 kg (3 lbs).

By R. S. McClain

The Federal Bureau of Mines investigated residues from aluminum plants, to determine if carbon could be removed by flotation while recovering fluorine and aluminum compounds for recycling to the reduction process. This publication summarizes studies on samples representing three types of plant waste products, supplied by three aluminum-producing companies. Samples of flue dust, pot skimmings, and pot linings from the various plants all responded to a simple turpentine flotation scheme to reject 90 to 97 percent of the carbon. Aluminum compound recoveries ranged from 42 to 94 percent on the flue dust, were about 95 percent on the pot skimmings, and ranged from 75 to 89 percent on the pot linings. Fluorine recoveries from the same samples ranged from 35 to 63, 92 to 95, and 77 to 86 percent, respectively. The pot linings contained soluble salts of aluminum and fluorine which were recovered by precipitation with sodium aluminate and carbon dioxide gas. Composites of residues from each plant responded to flotation much the same as the individual samples. Aluminum is produced by the electrolysis of alumina in a molten cryolite bath. The electrolytic reduction cell consists of a carbon-lined box containing a pad of molten aluminum which serves as a cathode, a carbon anode, and an electrolyte of molten cryolite in which the alumina is dissolved. Alumina is reduced to aluminum at the cathode, and carbon is oxidized at the anode.

Jan 1, 1961

By C. O. Karacan, S. J. Schatzel, W. P. Diamond

In coal mining, longwall mining is a preferred method to maximize production by extracting large blocks of coal that have been outlined with a set of development entries. In U.S. mines, longwall panels are typically 305 m (1,000ft) wide (with a continual trend towards even wider panels), and usually over 3,050 m (10,000ft) in length. The increasing size of longwall panels, while helping to increase coal production, may also increase methane emissions due to the exposure of the mining environment to a larger area of fractured, gas-bearing strata. Thus, understanding the impact of increased panel widths on methane emissions, and designing gob gas ventholes and bleeder systems accordingly, can enhance the safety of the underground workforce by reducing their exposure to potentially explosive accumulations of methane/air mixtures. As part of its mine safety research program, NIOSH’s Pittsburgh Research Laboratory has initiated a reservoir modeling effort to better understand the interaction of the various geotechnical factors influencing gas flow within and to the underground longwall mining environment. A focus of this modeling effort has been 1) the prediction of the incremental amount of methane emissions to be expected due to increasing longwall panel widths, and 2) optimizing gob gas venthole completion practices to capture more of the gas in the subsided strata above longwall panels before it can enter the ventilation system of the underground workplace. The history matching phase of the study has been carried out on a 381-m (1,250ft) wide panel in the Pittsburgh Coalbed. Simulations have also been completed for a 442 m (1,450ft) wide panel to estimate the incremental increase in methane emissions and the performance of current gob gas venthole placement configurations. Additional venthole placement configurations were simulated to investigate options for optimizing methane capture from the subsided strata above the wider longwall panel.

By J. C. Edwards

A series of four coal combustion experiments (I)' was conducted at the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory in the Safety Research Coal Mine to evaluate the response of optical and ionization smoke and CO sensors to a small 0.61 m square smoldering coal fire which transitions to flaming combustion in the presence of diesel emissions. With the increased utilization of diesel engines in underground coal mines, it is important to be able to discriminate fire products-of-combustion (POC) from diesel emissions. One proposed method to accomplish this is the deployment and interpretation of multiple sensors.

Jan 1, 2010

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 Keith D. Rosbury

The basic objective of this project was to determine the cost-effectiveness of dust control used on unpaved mine haul roads. Field testing was conducted at three surface coal mines (two in Wyoming, one in southern Illinois) for a total of 20 weeks. The highest control efficiency measured for a chemical dust suppressant, 82 percent, was for calcium chloride two weeks after application. Generally, however, the control efficiencies hovered in the 40 to 60 percent range over the first two weeks since application, and then decreased with time. After the fifth week, the limited number of data points suggest a control efficiency of less than 20 percent. Composite watering data were fairly uniform. Watering once per hour resulted in a TSP control efficiency of approximately 40 percent. Doubling that application rate increased the control effectiveness by about 15 percent to 55 percent. Chemical dust suppressants (primarily salts and lignons) can be shown to be more cost-effective than watering under some conditions. Data summaries and the analysis of data are contained in Volume I. Volume II contains basic data.

Jan 1, 1983

By Lynn L. Rethi

This U.S. Bureau of Mines report summarizes common obstacles found when attempting to implement health and safety strategies in small mines and small businesses in general industry. Recently, the U.S. Mine Safety and Health Administration focused much of its attention on addressing health and safety issues at small mines. Some of the more innovative interventions practiced by small businesses in general industry are discussed for consideration of their applicability to the mining industry. The most effective intervention strategy that was developed for small businesses is the Occupational Safety and Health Administration Consultative Program. The details of this program and other intervention strategies used by small mines and small businesses are presented.

Jan 1, 1995

By P. M. Ambrose, A. C. Fieldner

This , the 11th annual report of research and technologic work conducted by the Bureau of Mines on coal and coal products , is issued following the closing of the Bureau's war work on fuels and contains references to most of the published articles containing results of war investigations . The few remaining papers will be discussed in next year's report . The trend in coal research in the Bureau of Mines was discussed in Mechaniza- tion . This publication , covering the period from the close of armed con- flict to resumption of normal coal -research activities , includes a section never previously presented . There is included for the first time a discussion of the Bureau's activities in the Liquid Fuels and Lubricants and the Solid Fuels Subcommittees of the Technical Industrial Intelligence Committee . This report does not replace the more comprehensive ones prepared by individual authors and listed as footnote references in this publication . purpose is to bring to the reader a résume of the work for the fiscal year ended June 30 , 1946. The material presented herein is based largely upon publications , but the results of some research and testing, which would not otherwise be published in the near future, are presented in detail .

Jul 1, 1947

By F. L. Wideman

This paper is one of a series on mining methods being published by the Bureau of Mines. It describes briefly mining practices at the Sunrise iron mine of the Colorado Fuel & Iron Corp., Platte County, Wyo. The Sunrise mine is in the Hartville iron district in east-central Wyoming (fig. 1). The district covers part of the Hartville Mountains, a region of moderate relief in which erosional features have been formed by the dissection of a low plateau. Altitudes vary from 4,300 feet along the North Platte River to 6,000 feet in the uplift. The climate is semiarid, with hot summers and winter temperatures below zero for short periods. Grasses, cacti, yucca, and low desert shrubs grow at lower elevations. Cottonwood and boxelder trees and willows grow along permanent streams; juniper and coniferous trees are confined to the higher elevations.

Jan 1, 1956

The Bureau of Mines is active in programs pertaining to solid waste disposal and land reclamation. Nine reclamation projects of mining companies and six projects of the Commonwealth of Pennsylvania were investigated to provide information on the procedures, costs, and results obtained from reclamation projects of bituminous coal-waste disposal areas. Refuse disposal costs of mining companies ranged from 9 to 28 cents per ton-mile, and quantities disposed of ranged from 600 to 4,500 tons per day. Spreading and compacting the refuse at the dump site ranged from 3 to 20 cents per ton. Cost of covering with soil and planting ranged from $750 to $1,646 per acre. Total costs of reclamation for the Pennsylvania projects ranged from about $1,800 to more than $15,000 per acre. Refuse preparation costs ranged from $772 to $5,550 per acre. Soil covering and planting costs ranged from $1,083 to $5,086 per acre. The best results were obtained by soil preparation and conditioning prior to planting. The type and depth of soil and effect of climate were also factors.

Jan 1, 1973

By E. S. Leaver

The gold that is not recovered by a particular process is refractory to that process. A study to determine how the refractory gold is associated in the ore constituents usually indicates the needed improvement in the process or additional methods for bettering recovery. In preliminary work, segregation of the various minerals, gangue or impurities, and data showing the reactions of each in the recovery method readily confines the refractory gold to a certain part on which extensive research can be directed. In this dissecting plan, the microscope is an important aid in locating the refractory gold but should be supplemented by chemical tests.

Jan 1, 1934