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"While control of dust-related diseases, the objective of the Generic Mineral Technology Center for Respirable Dust, is of prime importance from the human standpoint it is also essential to the economic well-being of the mining industry (FIGURE 23). Although significant progress has been made, the problem continues to be a major concern to the mining community. An increasing global demand for coal and other minerals means that production and the number of miners employed is on the rise. Therefore, the importance of this research to the mining industry cannot be overemphasized.The five areas of dust research are 1) control of dust generation, 2) dilution, dispersion and collection of dust in mine airways, 3) characterization of dust particles, 4) interaction of dust and lungs, 5) relationship of mine environment, geology, and seam characteristics to dust generation and mobility. Some experimental projects where the research is conducted almost exclusively in the laboratory may still rely on industry for imput. No industrial resources are necessary to the research of the non-experimental projects, for example computer modeling .The remaining research is classified as experimental and these projects do require interaction with industry in varying degrees. Periodic trips to mining sites in Western Pennsylvania, Southern Ohio, and West Virginia are necessary to record measurements or collect samples. Or companies may provide needed samples or equipment to the university for use in the laboratory. On several projects interaction is limited to advice or information supplied to the researcher by industry personnel."

Aug 31, 1989

By C. B. Manula, R. L. Sanford, R. A. Rivell

PART I. FLOW CHARTS

Jan 1, 1974

By G. Esterhuizen, C. Karacan

Methane can be a significant hazard in coal mine longwalling operations and extensive methane mitigation techniques are employed by coal mine operators. Reservoir modeling techniques are used to better understand the liberation and migration of methane from the surrounding rocks towards the mine ventilation system. The caved rock behind the advancing longwall face, known as the gob, can contain high void ratios, providing high permeability flow paths to the methane. The gob is progressively compacted by the weight of the overburden, resulting in a reduction in the void ratio and associated permeability. Estimating the permeability distribution within the gob poses challenges due to its complexity. The authors have developed a new methodology to determine both horizontal and vertical variations in the permeability of the gob. Variations of the permeability in the vertical direction are based on a model of caving and block rotation, which considers the effect of block dimensions and fall height on the void ratio. Gob compaction by the overburden and associated permeability changes are determined from a three-dimensional geo-mechanical model which simulates the gob as a strain hardening granular material. The resulting three-dimensional permeability distribution in the gob is then transferred to a reservoir model. The paper demonstrates the application of the method and shows that reasonable results are obtained when compared to empirical experience and measurements.

This chapter analyses the parameters influencing initial design of communication systems, for new mines and upgrading existing systems. Paragraph 5.2 outlines those variables that must be taken into account during the design stages of a new wired phone system. Recommended features, general requirements, and how they can be implemented are treated in this section. Paragraph 5.3 describes ways of improving or extending the range of trolley carrier phone systems and pager phone systems already installed in the mine. 5.2 New Phone System Design The task of designing an adequate communication, control, and monitoring system for an underground mine must be addressed on a system basis. In addition to insuring that effective voice communication is established, any new system should take into account present and future requirements of remote control and monitoring functions. Chapter 4 illustrated the drastic savings in response time that can be realized when remote control and monitoring are integrated into the overall communication system. The importance of including control and monitoring in the overall design plan for any system cannot be overemphasized. Because each mine is unique, and thus usually has its own special operating characteristics and communication requirements, there is no such thing as "the one best system" to meet the requirements of all mines. The optimum communication, control, and monitoring system for a mine must be one that has been tailored to meet the special requirements of that particular mine. Factors that must be considered during system design include- a. Type of mine and mining methods (low- or high-seam coal, deep hardrock mine, stope caving, longwall, room and pillar, etc.). b. Maximum number of working sections. c. Expected mine growth rate and eventual maximum size. d. Haulage methods (tracked trolley, diesel, belt, etc.). e. Underground power distribution system (dc, ac, or both). f. Features desired (two-way radio paging, private line capability for emergency use, etc.). g. Redundant or backup systems for use during outages of the normal system. Although no two mines are alike, the following items have been established as the main characteristics desired for any underground communication system: 1. Multiple Communication Paths to Outside--the objective here is to give all telephones a second method of communicating with the surface. 2. Audible Emergency Signaling--the communication system provides the main means of alerting miners during emergencies. The system should include means to broadcast distinct audible signals for emergency signaling. Initiation of these signals should probably be controlled from. a central outside point, such as a surface control room. 3. Emergency Override--provisions should be included to permit any conversation to be overridden with emergency communication. 4. Selective Area Page--as mines grow larger it is apparent that the entire telephone system paging mode need not be activated each time a call is initiated. When the general area of a

Jan 1, 1984

By D. Harrington

"A tabulation is printed below showing the accident record of the thirty-two mines of the Anaconda Copper Mining Co., in Montana, for the years 1915, 1916, 1917, 1918, 1919 and 1920, with summation for the six years. The table gives the number of shifts worked by each mine with the serious plus fatal accident rate for each 10,000 shifts worked.It is seen that in a total of 16,460,767.5 shifts worked by employees of the company's mines during this six-year period, there were only 2,005 serious and fatal accidents and of these, 200 were fatalities, leaving 1,805 serious accidents (a serious accident being one in which 14 or more days' time are lost). This is at a rate of 9,120 shifts per serious accident and at a rate of 82,304 shifts per fatality. Hence, if 300 days be adopted as a year's work, there would be one fatality per 274.3 years of work in these mines and one serious accident for every 30.4 years work.According to Bureau of Mines Technical Paper 286, (Metal-mine accidents in U. S. in 1919, by W. W4 Adams), during the years 1916, 1917, 1918, and 1919, the metal mines of the United States worked a total of 210,548,640 shifts and had 39,705 serious accidents. During the same years, according to the following tabulation, the mines of the above-mentioned company worked 11,958,978 shifts and had a serious accident rate of 0.995 accidents per 10,000 shifts worked. If the metal mines of the United States, working these 210,548,640 shifts, had this company's serious accident rate of 0.995 serious accidents per 10,000 shifts, the total number of serious accidents would have been only 21,000 or the country's metal-mine serious accidents would have been reduced nearly one-half, and there would be 18,705 fewer serious accidents than actually occurred."

Jun 10, 1921

By Jr. Taylor

The following heats of solution have been measured in 1.160 molal H2SO4 at 25° C: AH298, kcal./mole Be(c) + 77.44(H2SO4?47.849 H2O) H2(g) + BeSO4 (soln) -92.83 ± 0.11 BeSO4 ?(c) + 77.44 (H2SO4?47.849 H2O) BeSO4(soln) -16.45 ± 0.02 BeSO4?2H2O(c) + 77.44(H2SO4?47.849 H2O) BeSO4?2H2O(soln) -5.395 ± 0.019 BeSO4?4H2O(c) + 77.44 (H2SO4?47.849 H2O) BeSO4?4H2O(soln) 1.513 ± 0.010 Combining these data with other experimental results and data taken from National Bureau of Standards information yielded the following heats of formation at 298° K:

Jan 1, 1966

By N. S. Dalal, Xianglin Shi

"INTRODUCTIONEpidemiologic studies of workers in chromate-ore related industries, 1-3 and stainless steel welding and related occupations4 have shown that they have about 20-40 times higher risk of throat or respiratory track cancer than controls. Although the actual carcinogenic substances were not identified in these statistical studies, Cr(VI) compounds (for example, calcium chromate, zinc chromate, and lead chromate) were implicated as the causative agents, whereas Cr(III) compounds were not suspected as carcinogens. s These suggestions were supporte4 by laboratory studies wherein many Cr(VI) compounds produced sarcomas at the implant or injection sites.1,5 Squamous cell carcinomas and adenocarcinomas closely resembling human lung cancer were induced by intrabronchial implants of calcium chromate in rats, 6·7 whereas Cr(DI) oxide and Cr(lll) sulfate did not induce any tumor formation.6,7While the mechanism of the chromate-induced carcinogenicity is not fully understood, it is generally thought8 that it involves some damage to DNA. Specifically, it has been reported that: a) the chromate ion, henceforth referred to as chromate, can pass through the cell membrane and enter the cell while CR(DI) does not, 9 b) chromate does not interact with either native or denatured DNA 10 while Cr(III) does, 11 and c) the final Cr-DNA complex isolated from cellular reactions of chromate is Cr(III)-DNA, with Cr(III) binding to the phosphate groups.12,13 Thus the important question is: since Cr(DI) cannot pass through the membranes, how does Cr(III)-DNA complex form? For this to happen, Cr(VI) must be reduced to its lower oxidation states, 14 ultimately to Cr(III), by some reductants in the cellular environment. Unless this reduction occurs, the DNA would not be damaged and therefore no chromate carcinogenicity would ensue. Thus the reduction of chromate to its lower oxidation states seems to be a key step in the chromate carcinogenicity .1s One of the major reductants in cellular environments is thought to be glutathione (GSH), both outside and inside the cells.16-lB Some evidence for the role of GSH in the chromate toxicity was provided by recent studies showing that exposure of hamster cells to non-toxic levels of added selemite increases the levels of GSH as well as the Cr(VI)-induced DNA strand breaks,19 and that such DNA strand breaks in hepatocytes also change in direct proportion to the GSH content. 20,21 These observations were interpreted as implying that the reduction of chromate by GSH to some reactive intennediate is an important step in the chromate carcinogenicity. 20.21 In · the present undenaking22 we have used electron spin resonance (ESR) and spin-trap methodology to investigate the reduction of chromate by GSH and find evidence for the involvement of the glutathionyl radical (GS ·) as well as Cr(V)-intermediates."

Jan 1, 1990

By David E. Morse

Burundi, a small central African republic located between Tanzania and Zaire, remained essentially a nation of small family farms in 1978-79 with approximately 95% of the population engaged in subsistance agriculture. Coffee and tea continued as the nation's major export commodities. Mineral exports, small tonnages of cassiterite, wolframite and bastnasite, accounted for an estimated 3% of total exports in 1978 and 2% in 1979, or $2 million2 in both years. Burundi's major mineral imports in 1978-79 were cement, iron and steel, and refined petroleum products. Abnormal weather conditions, a drop in world coffee prices in 1978, and the conflict in neighboring Tanzania and Uganda in late 1978 and early 1979 combined to re-strict economic growth in Burundi during 1978-79. The gross domestic product (GDP) posted a gain of 6.7% in real terms for 1978 and an estimated 2.5% for 1979 which was significantly less than the 13.7% recorded in 1977, a time of high world coffee prices. The manufacturing and construction sectors were hard hit in 1979 by the conflict between Burundi's eastern neighbors because of transport disruptions which made building materials and manufacturing inputs almost unobtainable.

Jan 1, 1981

By Charles W. Huggins

The Bureau of Mines investigated palygorskite, a natural asbestiform material, to accumulate knowledge that might serve as a foundation for future synthesis of a similar material. Unit cell, chemical analysis, DTA, TGA, optical constants, and electron microscopy data were obtained. Selected palygorskite samples of bettor than 97-percent purity were used to obtain this information. Chemical analysis revealed the following formula: (OH2)4 (OH)2 Ca0.01Fe0.02K0 .c3Mg2.10A12.00Si7.93020.3.91 H2O. The optical constants for sodium light are a = 1.522; S = 1.530; ?=1.533; biaxially (-). The following orthorhomibic unit cell constants were determined: ao = 12.690 A, Z = 2, bo = 17.857 A, Dx = 2.327. co = 5.207 A, Identical diffraction patterns resulted from the three palygorskite samples that were studied. X-ray, chemical, DTA, TGA, and optical data were compared with literature values for similar fibrous materials. X-ray diffraction lines were indexed. Several electron micrographs were made to compare the structures of palygorskite and attapulgite with that of chrysotile. The micrographs revealed extremely short laths for attapulgite, very long flexible laths for palygorskite, and tubular structure for chrysotile.

Jan 1, 1962

By John W. Frey

This paper presents one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of Persia has been prepared from the best available information in Washington but is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers , to whom it is being referred through the courtesy of the Department of State .

Nov 1, 1929

By A. C. Fieldner

"Purpose and Nature of Tests:The rapidly increasing use of motor vehicles and trucks in the United States is creating an entirely new problem in the proper ventilation of tunnels, subways and other confined spaces through which such machines must pass. This problem has become of immediate importance because a tunnel 3,000 ft. long is being designed to pass under the Hudson River between New York City and New Jersey. Another tunnel at Pittsburgh 5,700 ft. long through the South Hills, is already under construction, and a third tunnel, 6,000 ft. between Boston and Past Boston is proposed. It is probably that other tunnels will be started in various parts of the United States in the near future.The ventilation of such tunnels is a serious matter, on account of the poisonous nature of automobile exhaust gases. It not uncommon to read about finding a man dead in his garage. Generally this happens on a cold, winter morning, after he has been running the engine with the doors and windows closed."

Mar 1, 1920

By Paul H. Mutschler

The Bureau of Mines sponsored a study of the impact of changing technology on the demand for metallurgical coal and coke to 1985. Individual technologies were analyzed to determine what effect each had on the demand for and the consequent consumption of metallurgical coal and coke in the steel industry. The domestic steel industry demand for metallurgical coal and coke for the production of hot metal will probably increase through 1985. Formcoke if implemented on a worldwide basis could begin to supplant the U.S. export market for metallurgical coal. The major technologies that have contributed to the decline in demand for metallurgical coke per ton of hot metal are (1) the increased usage coupled with higher iron content of agglomerates, (2) modification of blast furnace practices such as high top pressures and blast temperatures, and (3) increases in the injection of supplemental fuels. The projected demand for metallurgical coal and coke under current technology for 1985 are 109.4 and 76.0 million tons, respectively. With future technology implemented, the demand for metallurgical coal and coke will be 82.0 and 56.9 million tons, respectively. The projected domestic demand for metallurgical coke could further decrease by as much as 15 to 20 million tons by 1985 if formcoking proves technologically and economically feasible.

Jan 1, 1975

By G. R. Hopkins

[Apparent progress in economy at petroleum refineries, as measured by the average amount of hest units required to refine a barrel or crude oil, received a set-back in 1938, when the average rose to 567,000 B. t. u., compared with 562,000 B. t. u. in 1937 (see fig. 1). The primary factor in the rise in average heat requirement's per barrel of crude oil refined in 1938 was the decline in total runs to Invariably the average requirement increases when crude inn to stills decline, and vice versa. In other words, annual gains in fuel efficiency at refineries are masked by the degree to which the capacity is utilized. Additional crude runs give lower average heat requirements in two grays first, because they are mane with the expenditure of cc-comparatively small amounts s of auxiliary heat, and, second, because additional runs generally represent simple topping operations. In 1938 crude runs to stills declined 1.6 percent (from 1,183,440,000 barrels in 1937 to 1,165,015,000 barrels in 1938), but the total heat consumption declined only 0.4 percent, or from. 663,866 billion B. t. u. in 1777 to 660, 56 billion in 1938.]

Jan 1, 1939

By J. M. Kuchta

The chemical and thermal criteria used for predicting the spontaneous combustion hazard are briefly reviewed and data are presented to characterize the gas desorptions and self-heating tendencies of 29 U.S. coals. Closed vessel desorption experiments showed that CO, CO2, and CH4 are the main gases evolved and that the CO, CO/?O2 index, and 02 absorption rate increase with decreasing rank and increasing oxygen content of the coal. In this Bureau of Mines report, the effects of temperature, moisture, and other variables are discussed together with the application of the data to the complex conditions encountered in a mining environment. An important finding is that the presence of CO alone in a mine is not necessarily an indication of a self-heating reaction of the coal. Based upon experiments conducted in an adiabatic-type calorimeter, the self-heating temperatures of lignite and subbituminous coals can be as low as 30° C, whereas the bituminous coals require a temperature of about 60° C or more. The self-heating hazard is greatest when the coals are dried and exposed to a high humidity condition, apparently as a result of the "heat-of-wetting." Generally, the hazard is greatest with the western coals of the United States.

Jan 1, 1980

By Larry A. Haas

The U.S. Bureau of Mines investigated the use of organic binders as substitutes for bentonite in agglomerating iron ore concentrate. Over 30 organic binders were evaluated at several dosage levels in laboratory tests. The binder groups producing the greatest green pellet strengths were natural gums (guars carboxyl methyl celluloses) and gelled starches. The nongelled and alkalized starches, starch acrylic copolymers) wood-related products, and dairy products were less effective but better than bentonite. The highest wet pellet drop numbers were obtained with binders that had a medium plate water absorption value (>500 and <10)000) in distilled water and a high slurry viscosity (>75 cP) at 6 pet solids. The highest dry compressive strengths were obtained with binders that gave the highest adhesive tensile strength (>4 kg/ cm2) on iron oxide lap-joint substrates. Pellets with 0.1 pct organic binder had lower compressive strengths and reduction disintegration indices than those with 1 pct bentonite, but higher reduction rates. Pellets with carboxyl methyl cellulose and gelled starch had higher softening temperatures than those with bentonite. Overall, the most promising binder is gelled starch. Its price makes it more cost effective than carboxyl methyl cellulose, and its pellets have metallurgical properties superior to those of bentonite pellets.

Jan 1, 1989

Introduction The NIOSH Office of Mining and Construction Safety and Health Research has redesigned its Mining Safety and Health Web topic page. The updated page incorporates a significant amount of new safety and health information, plus an improved layout to better serve stakeholder needs. It also provides back-ground information about the NIOSH Mining Research Program, including research awards, core competencies, unique labs, community and educational outreach, and a brief discussion of how the research program is structured. The new Web topic page can be found at www.cdc.gov/niosh/mining. "Search" Feature The redesigned Web topic page features improved search capabilities. The "Search Mining" feature on each page lets you search only the NIOSH Mining Safety and Health Web topic page. The user can still search the entire NIOSH Web page by using the "Search NIOSH" option. New Safety and Health Topics Developers expanded the "Safety and Health Topics" and reorganized the site to make it easier to find information. Each topic link now has a significant amount of new and updated information, as well as links to related topics of interest. Safety and health topics include dusts, diesel exhaust, hearing loss, contact with electric current, fires, explosives, ventilation, emergency management, new and older workers, and education and training. All topics can be accessed from the home page (Figure 1). Publications Although the Web topic page highlights many of the most requested publications on the safety and health topic links, you can find a complete list of downloadable publications as well. More than 600 mine safety and health publications are now downloadable from the page. Short summaries let the user quickly identify publications of interest. Products The updated Web topic page offers more than 120 NIOSH mine safety and health products, including training exercises, toolbox talks, videos, computer software, guides, and checklists, many of which are downloadable. If not, instructions are given on how to obtain copies. Some of our products include: • Software to analyze horizontal stress, design pillars for longwall mines, and select roof bolts for ground control. • Educational software including the Hearing Loss Simulator, which simulates the effects of noise and aging; and Coal Country, which teaches children about coal formation, mining techniques, and everyday uses of coal. • Utility software including the HazCom Helper software to assist individuals in writing a HazCOM plan, as required by the Mine Safety and Health Administration (MSHA), to track hazardous chemicals at their mine sites. • Guides for troubleshooting roof support systems, under-ground workstation design, and seating design. • Training exercises and videos that can be used for safety training. Data and Statistics General mining statistics are used by a wide variety of stakeholders. The NIOSH Mining Web topic page offers statistical graphs, tables, maps, fact sheets, and other publications that document the mining population, injuries, fatalities, diseases, and occupational exposures for all mining commodities. If users prefer to analyze data themselves, downloadable files of MSHA data are available. These cover employment, production, injuries, fatalities, and accident data from 1983 to the present and are available in both SPSS® and dBASE® formats.

Jan 11, 2005

Reduce the hazards to which mine personnel are exposed by providing safer procedures for removing dragline wire rope terminations. Background The termination points of wire ropes used on draglines consist of a wedge and socket that lock the rope in place through friction. These components must be separated when the wire rope is changed. At present, the cannon method is the most common procedure used to accomplish this. However this method, using a small cannon and primer (detonator) cord to propel a steel projectile that will knock the wedge out of the socket, has the potential of causing injuries to mine personnel and damage to equipment. The Bureau of Mines, has devised safer, and equally efficient methods of removing wire rope terminations. The Bureau began by studying the cannon method, its merits and draw-backs. Safety guidelines were then developed for the cannon method, and two alternative methods-the pendulum ram and hydraulic pusher-were devised and tested. The Cannon Method The steel projectile used to separate the wedge and socket in the cannon method was found to be very effective. However, the method poses the inherent hazards of any explosive de-vice-hazards that could be increased by lax work procedures. There is no strict uniformity in the manufacture of the cannon or in the work procedures used in the mines employing it. Hazards could be reduced, or even eliminated, with adaption of certain manufacturing and work-procedure guidelines, such as 1) making the cannon and projectile de-signs, as well the work procedures used, uniform, 2) ensuring separate loading of the charge and detonator with insertion of the detonator through a separate port, 3) connecting electrical firing circuits only after the charge and projectile are loaded and the cannon is placed in its final firing position, 4) using approved detonating devices, 5) anchoring the cannon before firing and, 6) placing armor netting over the cannon before detonation.

Jan 1, 1986

By David F. Gearhart, Thomas M. Barczak

This U.S. Bureau of Mines report examines the roof and floor contact pressure provided by the interaction of a shield with the surrounding strata. Controlled forces were applied to an 800-ton two-leg shield in the Bureau&apos;s mine roof simulator; the distribution of forces acting on the canopy and base of the shield were measured with 24 hydraulic pressure cells. Several influential factors that affect the load distribution were investigated: (1) the magnitude of loading (leg pressure); (2) the profile of the canopy, principally the upward-sloping tip; (3) the base-lifting device; (4) horizontal load acting on the shield; and (9 compliancy of the immediate roof and floor. It was concluded that the shield does not develop full canopy or base contact without deformation of the strata. Maximum contact pressures are developed at the rear of the canopy and on the toes of the base. Less than 10 pct of the available shield capacity is developed at the canopy tip despite the design intention to ensure tip contact. Horizontal loading reduced the toe pressure acting on the base by as much as 75 pct. The base-lifting device exaggerated the inherently high toe loading, increasing the contact pressure by more than 200 pct.

Jan 1, 1992

By Tobias W. Goodman

The U.S. Bureau of Mines used a contact drilling strategy with short-collared assemblies in order to rotary drill long horizontal methane drainage holes in the Beckley Coalbed near Glen Daniel, WV. By decreasing the thrust, and increasing the rotation of the drill bit when in contact with the roof and floor rock, assemblies with 1-ft (0.3-m), 10-ft (3- m), and 144 (43-m) long collars were made in deflect and stay in the coalbed. Successful application of this procedure resulted in holes drilled full length in coal with the original assembly including bit. The test assemblies deflected away from the original bearings of the holes during drilling and arced. Four holes were drilled to depths ranging from 478 ft (145.7 m) before the strategy was developed, to 4,034 ft (1,230 m) when the strategy was applied. Total length of the holes in coal was 8,590 ft (2,618 m). After 577 days the total methane captured by the holes was 221,600,000 ft? (6,276,000 m3). The methane flow rate peaked at 805,000 ft3/d (22,798 m3/d), then decreased to stabilize at 670,000 ft?/d (18,974 m3/d) after 6 months.

Jan 1, 1989

By David F. Smith, F. A. Hartgen

"Incidental to a cooperative investigation with the Carnegie Institute of Technology and the International Combustion Engineering Corporation on the burning characteristics of a powdered coal and the powdered semi-coke therefrom, the U. S. Bureau of :alas has determined the relative temperatures at which rapid self-heating occurs in these two fuels. Determinations were made on various screen sizes of the two fuels. Chemical analyses on different sizes were made in the bureau's Coal Analysis Laboratory, of which H. M. Cooper is in charge. The true densities were determined b the method given in Bureau of Mines Technical Paper 8.4The apparatus used in the determination of the temperatures for rapid self-heating was similar to that used by Wheeler A 10-gram sample of the fuel was placed upon a screen in a glass tube enclosed in a vertical electric furnace. The tube was surrounded with sand. One thermocouple -as imbedded in the sand and another in the fuel. Measurements of the temperatures were obtained at regular intervals with a recording potentiometer, as the furnace temperature was uniformly raised. Dry air was passed down through the fuel samples at a uniform rate of 123 c. c. per minute; the temperature of the air was substantially that of the furnace."

Oct 1, 1929