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Case studies from four western states are used to illustrate the impact of the environmental compliance process on the mining industry. The case studies were not chosen as a statistically significant sample of all mining operations in the western United States but were chosen as representative of operations on both public and private lands and in locations that exhibited varying degrees of involvement by governmental units, non-governmental organizations and the general public. Basically, each case study was chosen because some aspect of their environmental compliance process helped to illustrate an interesting point in the regulatory process. The criteria used to select the case studies were: mines located in different jurisdictional areas, mines located in varying geological areas~ mines located in areas having different historical relationships with mining: and operations that are in production as well as those seeking an operating permit. The variety of such projects should provide the necessary foundation to evaluate the impacts of the environmental compliance process in each location.

Jan 1, 1994

By R. L. King, J. Cervik, A. A. Campoli

The Bureau of Mines performed laboratory experiments to evaluate the triboelectric effect of particulate-laden gas streams on polyethylene pipe at various velocity, humidity, dust-size, and dust-load conditions. Charges in excess of 10 kV were produced on the outside and inside surfaces of laboratory pipe samples, when exposed to 40 pct relative humidity (RH) gas stream containing coal dust. However, no charges were produced in laboratory tests that duplicated the over 75 pct RH and dust-free gas streams found in working underground pipelines. Bare cop- per wire, which is wound around the polyethylene pipe in a 1-ft (31-cm) spacing and grounded, eliminated the charge on the outside surface of the pipe, but not on the inside of the pipe surface,

Jan 1, 1986

The Technology Transfer Seminar on Mine Communications held on March 21-22, 1973, at the Pittsburgh Mining and Safety Research Center, Bruceton, Pa., presented information about recently developed equipment, instruments, and techniques for use in mine communications systems. All of the basic ideas presented in the fine seminar are operational in the Bureau of Mines Safety Research Mine in Bruceton.

Jan 1, 1974

By A. Bartkowiak

The lower flammability limit of methane at 0 p.s.i.g. and ambient temperatures is 5.6 volume percent in chlorine, 5.2 in oxygen, and 5.0 in air. The corresponding upper limit values are 70, 60.5, and 15 volume percent, respectively, so that the range of flammable mixtures is greater in chlorine than in oxygen or air. The lower flammability limit of ethane at 0 p.s.i.g. and ambient temperatures is 6.1 volume percent in chlorine, 3.0 in oxygen, and 2.9 in air. The corresponding upper limits are 58, 66, and 12.5 volume percent, respectively. In this instance the range of flammable mixtures is greater in oxygen than in chlorine or air. Generally, the limits of flammability for both methane-chlorine mixtures and ethane-chlorine mixtures widen with increases in temperature and pressure.

Jan 1, 1960

By J. W. Horne, W. L. Finley, A. D. Bauer, D. W. Gould

"The Bureau of Mines and the State of Colorado are cooperating in an investigation of the oil shales of Colorado. in this report the yields and the results of analyses of the oil and, gas produced from a number of oil-shale samples from the principal deposits of Colorado and other oil-shale States, are compared with samples from Scotland and Australia, where the oil-shale industry has had its greatest commercial development, and also with a sample from Brazil *here extensive oil-shale deposits are found shale samples were not selected as being representative of the different deposits, but they illustrate the wide variation in the nature of the organic matter of different oil shales.A further study is being made of the chemical composition of the shale, distribution of nitrogen and sulphur. in the products, temperatures at which organic matter decomposes, and the results will be presented in subsequent Papers, With complete data available on the chemical composition of the shales, it may be possible to explain some of the differences in the nature of the products from the various shales,Most of the work described herein was done under the supervision of M. J. Gavin. L. C. Karrick, formerly of .the Boulder laboratory, assisted in the work and gave many valuable suggestions."

May 1, 1924

By Leonard Obert

[Tng occasional. rock noises in a nice caured by brc,*ing and ripping of the back, settling, and other cailscr, are well-known tc~ a11 mining en- gineers. These noises oftcn prececte certnin tpes of rock failure as such are used to e certain event a; w:,rnlngs. Senides t5ese audible rock noisee t'nere are, l?o\;evpr, even Iprger nw.iber of' s;Lba.J^;li5le rock mis~s, which must; be piclcell UT with sole type of vi-urr,tion rnicroyhoce and qli- fied in order tnnt :hey n;ny e heard. It v:zs s~v;,yestec" Ir, an evlier ? ,I a.ldible noises Ifureau of I.lines s~zb:ic;et.iod that n stud:r of t!ler;c! *- t mig!!t be useful ir. de temining roc^ movemrnt 3 preceding failure.]

Jan 1, 1941

By Thomas M. Barczak

Longwall roof behavior is characterized by strata displacements in both the face-to-waste (horizontal) and roof-to-f1oor (vertical) direc-tions. The roof support structure provides resistance to this motion by translation of these displacements into vertical and horizontal support loading. Observations indicate that the shield reacts with both a vertical and horizontal force to uniaxial convergence (displacement). However, there are different magnitudes depending on whether the displacement is vertical or horizontal. This makes it possible to use supports as monitors of strata activity and loading. The Bureau of Mines examined this behavior using a linear elastic model of the support structure with two degrees of freedom. Vertical and horizontal load reactions were related to associated displacement actions of the strata. This was done by determining the stiffness of the shield under controlled vertical and horizontal displacement motions in the Bureau's mine roof simulator. This report provides example predictions of strata convergence and isolation of horizontal support loading due to vertical roof convergence using the linear elastic shield model. The report also examines efforts to determine strata behavior by direct measurement of support displacement.

Jan 1, 1987

By M. Kanda, J. W. Adams

A system for measuring amplitude probability distributions (APD’s) of electromagnetic noise in coal mines is described and typical APD’s from an underground coal mine are presented. The APD is a basic statistic required for the design and analysis of communication systems, especially those intended for use in noisy environments, and where neither overdesign nor underdesign is acceptable. The rms and average field strengths are obtained by integration of the APD, and examples are shown at several frequencies. All field strength levels are given in absolute units. Selected frequencies cover the range from 10 kHz to 32 MHz.

Jan 1, 1973

By J. C. LaScola

Development of methanometers and anemometers for underground use in coal mines is reviewed. The first semicontinuous recording methanometer was developed in 1961 in West Germany. The Bureau of Mines developed an instrument using; pellesters that was a continuous recording methanometer. Expansion of freon gas created a vacuum which pulled the methane-air mixture through a tube to an electrically heated, catalyst-impregnated pellester where the mixture was burned. The National Coal Board of England developed a continuous recording methanometer based on the principle of the Davy flame safety lamp. A thermo-pile was used to sense the hurt output of the flame. Finally the Bureau of Mines improved its methanometer by eliminating the freon gas and using a diffuser head to a monitor methane-air mixtures. Development of recording anemometers proceeded from the use of a photo¬cell and light source to sense rotation of the Biram-type anemometer blades to the use of a Hall detector to sense, rotation by measurement of electromagnetic pulses.

Jan 1, 1969

By Maria I. De Rosa

Table 10 and figure 4 show the number of fires and fire injuries occurring at the surface of underground coal mines by state during 199&1999. Table 10 also shows by state the risk rate, employees' working hours, and lost workdays. A total of 65 fires occurred in 10 states. Thirteen of those fires caused 12 injuries and 1 fatality (the yearly average was 6.5 fires and 1.2 injuries). Four fues and one fire injury involved con- tractors. The Ewhr value was 97 x l O6 hr (Irr = 0.025); the LWD value was 6,206. Pennsylvania had the most fues (20 fues and 5 injuries), followed by West Virginia (1 6 fires and 1 fatality) and Kentucky (1 5 fires and 3 injuries). Among these states, Pennsylvania had the highest injury risk rate value (Irr - 0.095). Table 1 1, partly illustrated in figure 5, shows by time period the number of fires, fire injuries, and fire fatalities; risk rates; employees' working hours; and lost workdays. The number of fires and fire injuries show a decrease followed by an increase during the five time periods, accompanied by a decline in employees' working hours throughout the periods (see table 11 and figure 5). The Irr values follow patterns similar to those shown by the injury values. Tables 12- 17 show the number of fires by ignition source, method of detection and suppression, equipment involved, location, and burning material by time period. Figure 6 shows the major variables during 199&1999. Table 18 shows the number of fire injuries per number of fires causing injuries and total fires by year, ignition source, equipment involved, and location.

Jan 1, 2004

By Roy L. Wilfong

The linear expansion of high-purity oxides of yttrium, cerium, samarium, europium, and dysprosium was determined by the interferometric method for the temperature range 25° to 1,000° C. Single-crystal magnesium oxide and single-crystal aluminum oxide were used as reference materials. The bulk density and crystal form of the nonreference materials also were determined. The coefficients of linear expansion in the range 25° to 1,000° C were found to be 8.10 x 10-6 for yttria, 12.10 x 10-6 for ceria, 10.81 x 10'6 for samaria (monoclinic), 10.35 x 10-6 for europia (monoclinic), and 8.13 x 10-6 for dysprosia, each given in centimeters per centimeter per degree Centigrade. A detailed investigation of the interferometric technique for measuring thermal expansion in this temperature range was made. The interferometer was found to be a precise tool but only when adequate precautions were taken. These precautions are described.

Jan 1, 1963

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grindability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions2 issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor; if it is not, a price adjustment is made, Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1971

By M. J. Friedel, D. F. Scott, T. J. Williams

In an effort aimed at monitoring mining-induced stress changes that may influence ground failure, the US Bureau of Mines conducted a series of active 3-D seismic tomographic surveys at the Homestake (Lead, South Dakota) and Lucky Friday (Mullan, Idaho) mines. Existing rock bolts were used to mount geophones and as strike points for introducing seismic energy using a 3.6 kg sledge hammer. Travel time measurements were recorded spanning up to 160 m between drifts at several levels. The tomographic uncertainty was minimized by computing iso-velocity surfaces of constant probability based on statistics from multiple reconstructions and a threshold criteria. Periodic imaging using tomographic velocity surfaces demonstrated that temporal and spatial changes in the local stress field occurred in response to ground failure and stope advancement at a gold and silver mine, respectively. Keywords: Temporal imaging; Mine-induced stress; Seismic tomography; Geophysics

Sep 9, 1996

By Edward D. Thimons, Jay F. Colinet

Underground coal mining operations in the United States continue to increase productivity as mining equipment and practices are improved. Unfortunately, increased production also results in the potential for increased respirable dust generation and worker exposure. In response, US operations are applying basic controls at elevated levels and looking to emerging technologies in an effort to better control respirable dust levels. Ventilating air and water sprays remain the basis of dust control strategies for both longwall and continuous mining operations, and the level of application for these controls continues to increase. In addition, new technologies are emerging that have the potential to further reduce dust levels. The National Institute for Occupational Safety and Health (NIOSH) has been conducting research into methods to optimize existing control technologies and evaluate emerging control technologies. This paper will summarize control technologies routinely being used in underground coal mine operations, as well as provide a review of new controls that are being pursued.

By Russell C. Frith, David C. Oyler, Dolinar Dennis R., Christopher Mark

Unusual circumstances may require that a longwall retreat into or through a previously driven room. The operation can be completed successfully, but there have been a number of spectacular failures. To help determine what factors contribute to such failures, a comprehensive international database of 131 case histories has been compiled. The cases include six failures where major rock falls occurred in front of the shields, and seven even more serious failures involving major overburden weighting. The case studies suggest two types of room failure mechanism. The first is a roof fall type failure caused by loading of the immediate roof at the face as the fender or remnant longwall panel narrows. The second is an overburden weighting type failure caused by the inability of the roof to bridge the recovery room and face area, and affecting rockwell above the immediate roof. The data indicate that the roof fall type of failure is less likely when intensive roof reinforcement (bolts, cables and trusses) is employed together with higher-capacity shields. The overburden weighting failures, in contrast, occurred when the roof was weak and little standing support was used. Weighting failures were not greatly affected by the density of roof reinforcement. In one of the overburden weighting cases, in a Pittsburgh coal bed mine, stress cell, convergence, bolt load and extensometer data have been used to analyze the failure in detail. Key words: coal mining, ground control, longwall, recovery room.

By L. C. IlsLey

Cooperation between the United States Bureau of Mines and the Safety in Mines Research Board of Great Britain, continuous since 1924, has made possible this and other papers on safety subjects. Grateful acknowledgment is made to representatives of the Board for their assistance in arranging visits to several mine safety stations, and to F. R. Wynne, Deputy Chief Inspector of Mines, for arranging visits to mines in Great Britain and other countries in Europe. During the summer of 1927 the writer had the privilege of visiting the mine safety testing stations in great Britain, Belgium, Germany, and France, in the order named. All of these countries have large coal mines, many of which are rated as gassy. Therefore, when the installation of electrical equipment is contemplated, each of these countries is confronted with the same safety problem as is the United States - the development of electrical equipment that will not ignite gassy atmospheres which through neglect or accident might surround the equipment. The means employed by these countries in safeguarding gassy mines should therefore be of general interest to safety engineers in American coal mines, and it is proposed to give a brief survey for each of the four countries mentioned. The third of these surveys covers conditions in Germany.

Jan 1, 1929

By E. L. Rawlins

The Bureau of Mines, with the cooperation of the Natural Gas Association of America, has conducted a study of leakage losses from natural-gas transmission lines. This study has shorn that surveys to determine the leakage from transmission lines lead to line repair work that not only aids in the conservation of gas, but can be made to show financial returns of large magnitude.2 In order to conduct the study, it was necessary to develop accurate and reliable methods of determining the actual leakage from pipe lines. METHODS OF TESTING Three methods that were developed and used to determine the leakage losses from high-pressure natural-gas transmission lines are: (1) The "pressure-drop" method, (2) The "metering-in and metering-out" method. (3) The "metering-in" method.

Jan 1, 1926

By M. R. Geer

All the coal lands in Alaska are publicly owned, and the Federal Government is the principal consumer of coal. Therefore the Government has long been concerned with the wise utilization of the coal reserves of Alaska as well as with the availability of coals meeting the specifications for use in various Government installations. Coal preparation plays a key role in both of these areas of interest. The proper choice and operation of coal-washing equipment permits the mining of inferior deposits, minimizes waste of coal in preparation, and assures a prepared product of the best quality obtainable from the raw coal. Thus, from time to time, the Bureau of Mines has made washability examinations on most of the coals mined in Alaska. Generally, these examinations were made when new mines or new beds were opened, when construction of new preparation plants was being considered, or when the operation of existing plants could be improved by better knowledge of the raw coal. The purpose of this report is to bring together all the washability data available on the coals of the Matanuska Valley and Beluga River fields. The pattern of energy development for the rapidly growing Anchorage area is not clear at this time. Formerly coal was the only fuel available for large-scale space heating and power generation. More recently both oil and natural gas have entered the market, and several hydroelectric projects have been completed. Additional major hydroelectric projects are being considered. The role that will be played by coal in this competitive energy market is uncertain. However I if coal is the fuel used in future power plants or industrial installations, the information contained in this report will be useful in indicating the quality of the coals that can be supplied and in selecting proper preparation techniques.

Jan 1, 1962

By T. O. Llewellyn

The Bureau of Mines investigated the use of a heavy liquid in combination with fluid cyclones to separate brucite from a Nevada ore on a continuous basis, using a mixture of dibromomethane and trichloroethylene having a density of 2.44 grams per cubic centimeter. Single-stage cyclone separation produced a concentrate that contained 84 percent of the total magnesia at a grade, on a calcined basis, of 95.6 percent MgO.

Jan 1, 1974

By Leonard Obert

[Tng occasional. rock noises in a nice caured by brc,*ing and ripping of the back, settling, and other cailscr, are well-known tc~ a11 mining en- gineers. These noises oftcn prececte certnin tpes of rock failure as such are used to e certain ev';ent a; w:,rnlngs. Senides t5ese audible rock noisee t'nere are, l?o\;evpr, even Iprger nw.iber of' s;Lba.J^;li5le rock mis~s, which must; be piclcell UT with sole type of vi-urr,tion rnicroyhoce and qli- fied in order tnnt :hey n;ny e heard. It v:zs s~v;,yestec" Ir, an evlier ? ,I a.ldible noises Ifureau of I.lines s~zb:ic;et.iod that n stud:r of t!ler;c! *- t mig!!t be useful ir. de temining roc^ movemrnt 3 preceding failure.]

Jan 1, 1941