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By Fred N. Kissell, Jay F. Colinet

The two major lung diseases of miners are "blacklung" and silicosis. Blacklung, or pneumoconiosis, was first recognized as a disease of British coal miners in the 1600s. However, investigations into the cause of blacklung disease did not begin until the 1900s. The causative agent of pneumoconiosis in coal miners was thought to be silica until studies in the United Kingdom provided evidence that expo- sure to coal dust containing minimal silica could also cause pneumoconiosis. In the Federal Coal Mine Health and Safety Act of 1969, coal workers pneumoconiosis (CWP) was defined as "a chronic dust disease of the lung arising out of employment in an underground coal mine." Diagnosis of CWP is generally based on chest x-ray findings and a patient's history of working in coal mines, usually for 10 or more years. In its early stages, CWP is called "simple CWP." Miners with simple CWP are at increased risk of developing an advanced stage of the disease, called "progressive massive fibrosis" pMF) or "complicated CWP." PMF (complicated CWP) is associated with significant decreases in lung function and oxygen- diffusing capacity. PMF is also associated with breathlessness, chronic bronchitis, recurrent chest illness, and episodes of heart failure. Coal miners with silicotic lesions or PMF have an increased risk of tuberculosis and other mycobacterial infections. PMF may progress even in the absence of further dust exposure. This disease is also associated with increased mortality (National Institute of Occupational Safety and Health [NIOSH] 1995). The most recent study to determine the prevalence of CWP in coal workers was in the mid- 1990s. The average prevalence of CWP was 2.8%, but for those with 30 or more years in the industry it was 14%. For the 10-year period from 1987 to 1996, 18,245 deaths were attributed to CWP. The most frequently recorded occupation on the death certificate (70%) was mining machine operator (NIOSH 1999). Silicosis may develop when inhaled respirable crystalline silica (quartz) is deposited in the lungs. The clinical diagnosis of silicosis is based on (1) recognition by the physician that the level of silica exposure is adequate to cause the disease, (2) the presence of chest radiographic abnormalities consistent with silicosis, and (3) the absence of other illnesses (e.g., tuberculosis or pulmonary fungal infection) that may mimic silicosis. The radiographic patterns are often the same for CWP and silicosis; thus, these diseases are sometimes distinguishable only by work history or pathological examination. Chronic silicosis commonly involves 15 or more years of exposure to silica. The characteristic microscopic feature is the silicotic nodule. Chronic silicosis is often asymptomatic and may manifest itself as a radiographic abnormality with small, rounded opacities of less than 10 mm in diameter, predominantly in the upper lobes. Lung function may be normal or show mild restriction. Chronic silicosis is also associated with a predisposition to tuberculosis and other mycobacterial infections and with progression to complicated silicosis.

Acid pollution from abandoned mines causes serious contamination of major streams in coal mining areas. In Pennsylvania alone it is estimated that 3000 miles of streams are devoid of fish and plant life because of coal mine effluent.1 The pollution arises because water and oxygen react with iron sulfide in the mine cavity to produce sulfuric acid and iron sulfate, which later find their way back into surface streams. Two general approaches to the problem are possible: (1) prevent the acid-forming reaction from taking place, (2) treat the acid mine water after it is formed so that it will not be harmful to the ecology when discharged into streams and other surface waters. The work described in this report belongs in the first category - it was based on the assumption that acid formation in the mine cavity can be prevented by keeping water (one of the reactants) out of the mine. This was to be accomplished by-forming a waterproof seal over the mine cavity which would prevent the seepage of surface water into the mine. It was planned to form such a seal at or near the surface of the ground by applying latex to the soil. Ideally a dilute latex would be applied to the soil and would penetrate to a depth of two to three feet below the surface where it would be coagulated by reacting with a constituent of the soil or by other means., A seal below the surface of the soil would have several advantages over a surface seal - it would not be subject to destruction by traffic, frost or vegetation and, more important, it would allow the use of the top soil for many agricultural purposes. A preliminary feasibility experiment was performed prior to application for the present grant. It showed that it was indeed possible to form a sub-surface seal by means of latex. A core of soil was obtained locally (Wayne, N. J.) by driving a 6.5 cm inside diameter steel pipe about 100 cm long into subsoil for a distance of 71 cm. The soil was retained within the pipe for this experiment. A part of the free space above the soil in the pipe was charged with water, and the seepage rate of the soil after it had become saturated was 15 ml/min under a total head (wet soil plus supernatant column of water) of 92 cm. After the supernatant water had drained completely, 100 ml of 5% rubber latex was added and allowed to seep into the soil. This was followed by additional water and the seepage rate was found to be 2 ml/min under the same head. This seepage rate remained unchanged when remeasured on the following day. Since there was no visible evidence of the latex in the collected drain water it is presumed to have been retained by the soil.

Jan 1, 1972

Isometric strength is defined as the capacity to produce force or torque with a voluntary isometric (muscle[s] maintain[s] a constant length) contraction. The key thing to understand about this type of contraction and strength measurement is that no body movement occurs during the measurement period. The tested person's body angles and posture remain the same throughout the test. Isometric strength has historically been the type most studied and measured. It is probably the easiest to measure and to understand. Some strength researchers feel that isometric strength data may be difficult to apply to some "real life" situations because in most real circumstances people are moving - they are not static. Other researchers counter that it is equally difficult to determine the speed of movement of a person or group of persons doing a job (each moves in his or her unique manner and speed across the links and joints of the body). Thus, dynamic strength test data collected on persons moving at a different speed and/or in a different posture from the "real world" condition will be just as hard to apply. In truth, neither is better - they are different measurements. Both researchers and users should collect and use data that they understand and that fits their application. Workplace Assessment When a worker is called on to perform a physically demanding lifting task, the external load produces moments - tendencies to produce motion, also called torques - about various joints of the body.(1) Often these moments are augmented by the force of gravity acting on the mass of various body segments. For example, in a biceps curl exercise, the moment produced by the forearm flexors must counteract the moment of the weight held in the hands as well as the moment caused by gravity acting on the forearm's center of mass. To perform the task successfully, the muscles responsible for moving the joint must develop a greater moment than the combined moments of the external load and body segment. It should be clear that, at each joint of the body, there is a limit to the strength that the muscle can produce to move ever-increasing external loads. This concept forms the basis of isometric muscle strength prediction modeling.(1) The following procedures are generally used with this biomechanical analysis technique. First, workers are observed (and usually photographed or video-taped) as they perform physically demanding tasks. For each task the posture of the torso and the extremities are documented at the time of peak exertion. The postures are then re-created using a computerized software package, which calculates the load moments produced at various joints of the body as the task is performed. The values obtained during this analysis are then compared to population norms for isometric strength obtained from a population of industrial workers. In this manner, the model estimates the proportion of the population

Jan 1, 1998

By Th. G. Sahama

This paper contains some new thermodynamic data for silicates in the series Mg2SiO4-Fe2SiO4 and MgSiO3-FeSiO3 and Lives the result: of a thermodynamic attack on the problems of stability end paragenoses. Although some data are lacking, satisfactory agreement with mineralogical and petrological observations is indicated.

Jan 1, 1949

By William L. Rice

This Bureau of Mines Open Pile Report on cobalt is one of a series of minerals availability commodity deposit abstracts. Nonconfidential information from the Minerals Availability Program data base covering domestic and foreign cobalt properties and deposits has been abstracted for use in his report. Abstracts include applicable data on location, published reserves and resources, geology, mine and beneficiation systems, and operation information.

Jan 1, 2011

By W. I. Nelson

This paper which describes the milling practice of the Engels Copper Mining Co., is one of a series on milling methods being prepared for and published by the United States Bureau of Mines. ACKNOWLEDGMENTS Acknowledgment is made of the assistance rendered by J. Casagrande, mill foreman of the Engels concentrator, in collecting much of the data presented in this paper.

Jan 1, 1932

By A. F. Baker

Tests were conducted in commercial foundries to determine the suitability of calcined anthracite as a cupola fuel. The calcined anthracite performed satisfactorily at two of the three foundries where iron-melting tests were conducted. Performance at the third installation was unsatisfactory because metal temperatures deviated widely and, in general, were lower than is desirable for the type of castings being made.

Jan 1, 1963

By George T. Motock

The author prepared the following report as the result of a trip to Germany in the summer of 1945 for the Technical Industrial Intelligence Commitee Subcommittee on Metals and Minerals. The purpose of this committee, which functions under the Joint Intelligence Committee of the Joint Chiefs of Staff of the United States Armed Forces and of which the Bureau of Mines

Jan 1, 1946

By Robert H. Ridgway

This paper presents the results of the second in the series of annual canvasses on the consumption of ferrous scrap and pig iron in the United States, inaugurated in 1935 by the Bureau of Mines and published in Report of Investigations 3329. The study was undertaken in response to requests from trade organizations and others for detailed statistics on this phase

Jan 1, 1937

By G. L. Oldright

This paper is the thirteenth of the series on Smelting in the Lead Blast furnace, and the third of the series on Handling Zinciferous Charges. Two other papers have been written on the Rate of Descent of the Stock Column, and Formation of Accretions. These are Reports of Investigations 2963 and 3094, for the Tooele plant and the Bunker Hill plant, respectively.

Jan 1, 1934

By James E. Bell

Quartz crystals occur on a farm in the vicinity of Laurel Fork, Carroll County, Va., in abundance over a large area, This has been known for several years, but no work had been clone, up to the Bureau of Mines examination in 1943, to determine the amount of crystalline quartz of usable quality. Field exploration was undertaken throughout the month of June 1943.

Jan 1, 1950

By Jr. Gabler

Because of concern over the availability and reliability of an uninterrupted supply of manganese and other materials, the U.S. Congress requested that the U.S. Bureau of Mines (USBM) study the /low of strategic and critical materials in the economy to delineate and quantify the production areas where metal values are lost. As a result, the USBM developed a generic computerized commodity flow model that is readily amenable to updating. The original model developed for cobalt, with slight modifications, was used to track the flow of manganese. This report follows the flow of manganese through its metallurgical and chemical applications and highlights areas where significant losses occur owing to downgrading, export, or disposal. The study indicates that materials containing 695,000 short tons (st) of manganese were consumed domestically in 1990. Scrap recovery specifically for manganese recycling was insignificant. However, considerable manganese was recycled through processing operations as a minor component of ferrous and nonferrous scrap and steel slag. The major loss category is manganese lost in steel processing, 323,156 st or 46 pet of the 1990 apparent consumption. Most of this loss reports to steelmaking slags. Recovery from slags is technically feasible, but is not economically feasible.

Jan 1, 1995

By C. Özgen Karacan

The methane emission rate into an underground mine environment from overburden strata during longwall mining is impacted by reservoir and geomechanical characteristics of the coal measure rocks in the overlying strata, as well as the presence of any coal seam. The reservoir characteristics and how they change during mining potentially affect the performance of gob gas ventholes, which consequently impacts the efficiency of methane control in the mining environment. This study presents reservoir and elastic properties of coal measure rocks in the Lower Monongahela Group in Greene County, southwestern Pennsylvania, of the Northern Appalachian Basin. Since the source of methane in this region from underground mining is located between the Sewickley coal and the Pittsburgh coal, a specific emphasis was given to this interval. Core analyses were performed in the laboratory to determine rock porosity and permeability. Geophysical logging data (gamma, density, sonic) obtained from two exploration boreholes were used for evaluating formation boundaries, shale contents, log porosities, and geomechanical properties of formations. Permeability was also calculated using density-log data and empirical equations and compared with laboratory measurements and slug tests performed in isolated intervals of boreholes. The results presented in this study can be used as data sources for reservoir studies related to the production and control of methane.

Jan 1, 2009

By Donald I. Kurth

The Bureau of Mines conducted experimental work on comminuting coal. The size distributions of coarse fragments and fine particles were obtained under different modes of energy application--drop, impact crushing, wedge impact, compression, and shear tests. Four levels of energy application were used in the impact crushing and wedge impact tests. Airborne dust and respirable air-borne dust distributions were obtained for the impact crushing and wedge impact tests. Analyses of nonairborne dust and coarse fragment-fine particle distributions were carried out on impact, wedge, compression, and shear tests. The experimental size data on nonairborne dust were fitted to normal, log-normal, power law, Weibull, log-Weibull, and exponential distribution functions. Both the nonairborne dust and the coarse fragment-fine particle size distributions are best described by Weibull distributions. For the impact crushing tests, mean product size was found to be inversely related to specific crushing energy. The particle counts in a given size range of airborne and nonairborne dust were found to increase with increased input energy and specific crushing energy. However, in another sense the particle distributions were independent of energy level; that is, the percent-ages in a given size range were approximately constant regardless of energy level. Respirable airborne dust was related to respirable-size nonairborne dust by a power law.

Jan 1, 1975

By B. W. Jong

The Bureau of Mines studied reinforcement of sulfur concretes using glass, polyester, and aramid fibers. The objective of this research was to determine the feasibility of fiber-reinforcing the sulfur concrete to enhance the flexural properties. Optimum fiber sulfur concrete compositions were formulated with a cement-to-fiber ratio of 9.0:1 for glass-fiber and polyester-fiber sulfur concretes and 12.1:1 for aramid-fiber sulfur concretes. Test samples were prepared using techniques developed by the Bureau of Mines. Flexural strength values of up to 50 pct of compressive strength values were achieved with fiber additions. With non-fiber-reinforced sulfur concrete, the values ranged up to 20 pct. The impact strength and fracture toughness of sulfur concretes were increased sig-nificantly by reinforcement with glass or with aramid fiber and were adversely affected by use of polyester fiber. Strain tolerance was doubled and failure mode was shifted from catastrophic to noncatastrophic type by adding glass fiber. The glass-fiber and aramid-fiber sulfur concretes are resistant to acid corrosion and have proved durable in freeze-thaw cycles. This laboratory and field evaluation has shown that fiber reinforcement of sulfur concrete is feasible and that it enhances the flexural properties.

Jan 1, 1985

By R. V. Higgins

Many contributions to methods of forecasting the performance of waterfloods of a five-spot pattern have been made by investigators. In most of these forecasting methods, a previously selected sweep efficiency is used, and other simplifying assumptions are employed to obtain the objective. In this paper the calculated oil recoveries from several five-spot single- and multiple-layer stratified reservoirs were made with a minimum of assumptions, and because of the techniques used, no previously selected sweep efficiency was required. As a result, the accuracy of the forecast is increased. Permeability curves and continuously changing saturation gradients are used in every section of the pattern. By means of a potentiometric model, the flood pattern is divided into channels, the centers of which are the streamlines. The channels are divided into cells. As flood water enters, the permeability and saturation of each cell change with time. In this study the production from multiple-sand layers of different absolute permeability but with the same relative permeability-saturation relations are combined. The results are shown for a single- and 10-layer reservoir with a permeability variation of 0.60. The oil rate, water-oil ratio, and recovery are shown as functions of time for a 2- and 20-centipoise oil starting in primary phase and after fill-up.

Jan 1, 1962

By Joseph M. Singer

Ignition of hybrid coal dust - methane - air mixtures by hot- turbulent - pulsedgas jets was investigated . The turbulent jets were generated by explosions in a primary chamber of stoichiometric mixtures of methane , oxygen , and nitrogen . The hot - gas ignition apparatus provided an adjunct means of testing , on a small scale , the type of ignition that exists in large - scale galleries or in coal mines . = coal particle The temperature Ignition variables were channel diameter , channel length , size , fuel concentration , and temperature of the hot - gas jet . of the hot jet was varied by changing the oxygen indices ( OI ) of the primary explosion mixtures . Coal dust having approximately 37 percent volatile matter was used . 02 O2ટ + N₂ The hybrid coal dust - methane - air mixtures required higher jet temperatures ( higher oxygen indices ) for ignition than the single fuel component methane - air mixtures . Methane in air concentrations less than the lower flammable limit of methane could be ignited in the presence of coal dust if the jet temperatures were increased . A specific explosion transmission ( ignitability ) curve existed for each coal dust concentration . The total fuel concentrations at the lower limit of each ignition curve was always close to or greater than stoichiometric , indicating that not all the coal dust was involved in the ignition .

Jan 1, 1964

By N. A. Gokcen

This Bureau of Mines report reviews and summarizes recent studies of the rates of chlorination of aluminous resources with CO and C12 mixtures with and without COC12. No reaction mechanism could be obtained from the existing results; however, diffusional barriers in the gas and solid layers probably control the chlorination rate in thermogravimetric experiments. Fluidized beds of particles smaller than 0.1 mm appeared to show very little solid layer diffusional barrier. For optimum chlorination the particle size should probably be less than 8 mm, the calcination temperature approximately 700° C, and the chlorination temperature from 650° to 750° C. Relatively rapid chlorination with COC12 in thermogravimetric experiments was attributed partly to the simultaneous supply of reductant and chlorinator by one gas to the sample reaction site. Comparable results for chlorination of fluidized beds with COC12 are not available. Equimolar mixtures of CO and C12 produced the optimum rate of reaction. Addition to the calcine of 10 to 20 wt-pct NaCl accelerated the rate of chlorination, and addition of SiC14 to the gas mixture decreased the rate of chlorination of SiO2 drastically, but at the expense of chlorination of significant fractions of Al2O3. Further research in various areas is suggested.

Jan 1, 1983

By J. H. Holden, C. C. Shale, G. R. Strimbeck, W. S. Bowie

Electrical characteristics are presented for air in a 2 - inch pipe - type electrostatic precipitator operating under dynamic conditions at temperatures of 600 ° to 1,500 ° F and pressures of 0 to 80 psig using a negative discharge electrode . Results of this one - geometry study show that current - voltage relationships are a function of air pressure and temperature and indicate that precipitators can be used at any temperature through about 1,350 ° F over the full range of pressure . Corona starting voltage and sparkover voltage vary directly with pressure and inversely with temperature . At temperatures above 1,350 ° F use of precipitators may be limited to operations at pressures somewhat above atmospheric pressure . Theoretical derivations are presented that relate the effect of gas density on corona starting voltage and the effect of ion mobility on corona current . Deviation from the theory is noted at high current levels . Theoretical discussion is presented to explain the apparent electrical limitations for use of precipitators at high temperature , low gas density , and high corona currents , conditions at which calculated ionic velocities are extremely high . Experimental results are interpreted in terms of the theory presented . 1,500 ° F thermal ionization does not appear to be a critical factor .

Jan 1, 1963

By Susan E. Brink

The first step in determining whether Mn can be recovered by in situ leaching is to develop and test a selective lixiviant. Two column leach tests and one core leach test Were conducted by the U.S. Bureau of Mines on Mn oxide ore using aqueous sulfur dioxide (SO2) as the lixiviant. The column tests showed that aqueous S02 could selectively dissolve available Mn oxides from calcite-rich ore in a heap leach system. However, the core test showed that calcite gangue side reactions can have pronounced negative effects on the likelihood of successful in situ leaching of a calcite-rich ore with aqueous S02. Petrographic and geochemical analyses showed that both Mn (IV, III) oxides and calcite were dissolved. The abundance of dissolved Ca caused precipitation of gypsum. Acid consumption by calcite dissolution caused a rise in pH that caused the SO/S species to shift to S032-(sulfIte), which hindered reductive dissolution of Mn oxide. Gypsum precipitation did not affect complete leaching of the rock fragments in the column tests; however, it plugged the natural permeability in the core. Manganese recoveries were high for the column tests and low for the core test.

Jan 1, 2010