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Provide d comprehensive source of up-to-date information about technology for revegetating coal mined lands. Approach A great deal of activity and research in the field of coal mine revegetation has been reported in technical literature, both before and after the passage of Public Law 95-87, the Surface Mining Control and Ruclamation Act of 1977 (SMCRA). This information is widely scattered throughout books, scientific journals, periodicals, Government reports, and other sources, and there has been a need to develop a method of accessing it quickly and efficiently. At the request of the Office of Surface Mining Reclamation and Enforcement which promulgates and enforces regulations implementing the act, the Bureau of Mines has prepared a document that identifies literature relevant to coal mine revegetation. Most of the literature available on this subject has been published during the past 15 years. To tap this reservoir of information, 14 data bases were accessed from DIALOG SDI (Selective Dissemination of Information) Service using three keyword combinations (surface mining and reclamation, strip mining and reclamation, and revegetation). This procedure generated over 7,000 listings. The U.S. Department of Energy's ENERGY data base was selected from the 14 DIALOG bases, both for its large number of listings and for its broad coverage of literature. This data base contains all the unclassified information that passes through the Technical Information Center of the Department of Energy, including reports, journal articles, conferences, patents, books, monographs, theses, and engineering materials relating to energy development.

Jan 1, 1986

Improve the reliability and accuracy of subsurface images using constrained tomography with enhanced ray-tracing capabilities. Background Geophysical tomography is a technique for imaging the structure of a rock mass using seismic or radio waves, in the same way that medical CAT scans image human tissue using X-rays. Tomography has found numerous practical applications related to mining, including lithologic and structural characterization, fracture detection and fluid monitoring, void detection, and evaluation of stress state and integrity of mine structures. Problems Two fundamental problems have largely prevented geophysical tomography from enjoying the tremendous success achieved by medical tomography. The first is a consequence of practical limitations on the placement of sources and receivers of wave energy: ideal resolution can be attained only when the region being imaged is entirely surrounded by sources and receivers, so that it is crossed by rays traveling in all possible directions. When such coverage is impossible or impractical, the inversion becomes underdetermined: there id not enough information in the measured data to provide a mathematically unique solution. The second major problem in geophysical tomography is the necessity for detailed ray tracing. Commercial software, as well as previous U.S. Bureau of Mines (USBM) software, employs a ray-shooting algorithm that may be unable to model some ray paths when velocity contrasts are larger than about 100%. These ?shadow zones" result in loss of data and degradation of reconstructed images.

Jan 1, 1994

This report describes magnetic field measurements in the Helvetia Coal Co. Lucene #8 Mine for purposes of deriving a mapping of the magnetic field strength covering the major haulageways which contain conductors. The measurements were performed by Terry S. Cory, P.E. under U.S. Bureau of Mines purchase order P0372716. Assisting in performance of the measurements were personnel from the Bureau of Mines, PMSRC, and Helvetia Coal Co. Acknowledgement is given to Engineer Tom Strong of Helvetia Coal Co. who accompanied the measurement team and who lended support in performing the measurements and in supplying valuable engineering information for use in evaluation of the results. The results of the testing at medium frequency show that coverage of the entire mine area containing conductors can be achieved employing wireless radio techniques whereby radio signals are coupled into and are carried by these conductors. These results confirm earlier qualitative testing of the Collins Mine Wireless Radios in this mine. These results, performed over the frequency range 71-2890 KHz, illustrate the effect of frequency on the radio propagation with the conclusion that the best overall coverage is obtained at frequencies approximating 1000 KHz. This report presents all the raw data and the reduced data in the form of magnetic field strength contour maps. Sufficient information is provided to enable independent reduction of the data. A summary of observations which can be made directly from the contour maps is given.

Jan 9, 1977

By Roy H. Grau

Increased awareness of a healthy work environment is common to all industries and the stone industry is no exception. The presence of operating diesel equipment, welding, stone production blasting, and silica dust in a working environment all contribute to air quality issues in underground stone mines. Particularly recognized is the exposure of workers to diesel particulate matter (DPM). Recent regulations call for a DPM standard of 160TC ug/m3 (TC = Total Carbon). The National Institute for Occupational Safety and Health (NIOSH) has conducted research to improve the ventilation of these mines and consequently reduce the exposure of workers to harmful airborne contaminants. The results have shown that the ventilation of underground stone mines can be significantly enhanced using improved ventilation controls and techniques. Large-opening stone mines present specialized ventilation challenges because their entries are much larger than in other types of mines. Most stone mines have entries about 40 feet wide and up to 30 feet high, with bench areas that may extend even higher. These large entries present the positive opportunity to move large air quantities at relatively low mine fan pressures resulting in lower fan horsepower and reduced operating costs. However, the difficulty in ventilating large-opening mines is that even with large air volumes, the air velocity is often less than 100 feet/minute. Higher ventilation velocities more quickly dilute and remove contaminants from the face areas. Higher ventilation airflow velocities can be achieved by effective ventilation planning and proper choice of ventilation fans.

Jan 1, 2009

By Harold C. Pierce

"INTRODUCTION During the years 1941 to 1945, the United States produced less than one-half of one percent of all primary nickel, whereas the nation's consumption of the metal amounted to nearly three-fourths of the world's supply. Although postwar nickel consumption probably will be less than wartime consumption, trade- estimates for the next 10 years are well above the average established during the 1930-1940 decade. The greatest consumption is expected in nickel alloys, particularly nickel-alloy steels. 3/ The greater use of nickel cast irons and nickel-clad metals also signifies an expanding nickel market. In anticipation of the postwar demand for nickel, and realizing the seriousness of the ""have not"" position of the United States with respect to this metal, the Bureau of Mines, sent an engineer 4/ into the lower Copper River region of Alaska during the summer of 1944 to investigate the nickel deposits near the head of Canyon Creek. Samples from the Spirit Mountain nickel prospect were sufficiently encouraging to justify more intensive exploration. As a result, a program of surface trenching, systematic sampling, and detailed mapping of the property was adopted and directed by a Bureau of Mines engineer 5/ in the summer of 1945."

Aug 1, 1946

By Earl R. McMillan

"Coal washing commands the thoughtful attention of a steadily incre in number of people. Clean coal is not merely a luxury but is rapidly becoming a necessity in some industrial operations.Coal seams in the Northeast are rarely free from ""bone"" and shale or clay partings which vary from a fraction of an inch to several feet in thickness. Nearly all of the coal measures are folded and faulted, the coal seams dip at various angles, and in some cases are badly broken. In mining these seams fragments of the roof and floor, as well as partings of impur-ities within the seams, unavoidably become mixed with the coal, so that the raw coal as it comes to the surface often contains as much as 50 per cent, by weight of waste.At the Bureau of Mines experiment station at Seattle, the washing of this coal in order to improve it for commercial use has been studied. Since the process of coal-washing depends upon differences in specific gravity between the clean coal and, its associated impurities, the first problem undertaken was that of determining the specific gravity of the clean coal and of each parting of impurity contained in a large number of representative seams.It was found that the freshly-mined coal is practically saturated with water, this being observed in determining the effect of moisture content upon the specific gravity of the coal particles, selected from samples of coal varying from low-grade subbituminous up to semianthracite, all of which are found in the State of Washington. The specific gravity values determined for the cleanest particles varied from 1.28 to 1.35; in general, the higher the rank of the coal the hither the specific gravity."

Nov 1, 1920

By R. L. Grayson, T. Simonyi, R. A. Andrel

"The purpose or this paper is to disclose analytical, statistical, and observational results relating to mineralogy and trace elements in respirable dust samples collected from two different mines in West Virginia. Samples were taken from longwall panels, and the panels operated in different coal seams, one located in the northern part or the state and the other in the southern region. Mining conditions and equipment arrangements on the panels will be described along with dust control techniques used. Results from sample analyses are summarized with emphasis on relationships between mineralogy, trace elements and mineral particle size to worker locations. Correlations are made between micro x-ray diffraction and energy dispersive x-ray analyses for sample mineralogy.IntroductionThrough the work of many researchers worldwide, the health of coal miners in modern societies is now protected from harmful exposure to respirable coal mine dust. A vast amount of research culminated in the exposure-response model of Jacobsen, et al, (l) which has been used to establish the 2 mg/m3 exposure limit in the United States. According to the model exposure to respirable dust for 35 years at this level or less could prevent the occurrence of a clinically significant case of coal workers' pneumoconiosis (CWP) in a miner. The exposure limit, of course, must be adjusted whenever greather than five percent free silica exists in the respirable dust.The Jacobsen model was built around a mean mass concentration exposure, which generally showed the highest correlation with both incidence and progression of CWP. As Morgan, et al noted, however, the quantity of respirable dust inhaled is not the only significant factor. 2) They noted that although mass of respirable dust correlates highe.st with the incidence of CWP, it is not a causal factor. Admittedly, the insidious processes causing the disease occur at the lund cell-dust particle level."

Mar 1, 1989

By B. Dimitriades

Data on smog-forming reactivities of exhaust aldehydes are scarce. Such data were obtained by irradiating in a smog chamber typical exhaust aldehydes, individually and in exhaustlike mixtures. Observed reactivity manifestations were rate of nitrogen dioxide formation (RNO2) and yields of oxidant, peroxyacetyl nitrate, and formaldehyde. Results showed that exhaust aldehydes vary widely in reactivity. Formaldehyde showed high RNO2 reactivity but low oxidant yield; benzaldehyde, [m]-, and [p]-tolualdehyde were totally unreactive when irradiated individually; [o]-tolualdehyde was reactive. In mixtures, benzaldehyde manifested reactivity in terms of peroxybenzoyl nitrate yield. Exhaust aldehydes as a group are judged to be as reactive as the exhaust olefin group. The importance of the aldehyde contribution to exhaust reactivity and methods for assessing such contribution are discussed.

Jan 1, 1971

By Jerry W. Ramsey

The Bureau of Mines studied two Pennsylvania anthracites using low-temperature carbon dioxide adsorption. A modified form of the Brunauer-Emmett-Teller equation was used to calculate specific surface areas. Two mesh sizes of each anthracite were used to determine how gamma irradiation at 106 and 108 rads, both in vacuum and in the presence of air, affected the carbon dioxide surface areas. Results show that anthracites have a system of pores that are essentially all interconnected rather than isolated; that anthracites differ from one another in specific surface, which may correlate with density; and that irradiation in vacuum has no discernible effect on specific surface of anthracite, but irradiation in air does produce changes in specific surface.

Jan 1, 1966

By Dennis R. Dolinar

The danger to personnel, equipment, and pillar structure created by the spalling of a coal rib can be minimized by installing rib bolts. To assure that a configured support system will maintain a coal rib, the U.S. Bureau of Mines developed a rib bolt system based on a nonpreventable failure concept. A statistical equation quantitatively relates the amount of rib retained to the bolt spacing and the width of the spalled material. Laboratory test results show that the equation accurately predicts the amount of material retained and confirm the validity of the support concept. The examination of rib bolting at a coal mine experiencing rib sloughage provides evidence that the effectiveness of the support can be related to the failure pattern of the spalled material. An analysis of roof and roof support reaction to rib sloughage at the mine indicated that the rib sloughage had little effect on roof stability. Although supporting ribs might not affect roof stability, laboratory test results indicate that the material retained by the support can sustain a load up to 20 pct of the intact compressive strength of the material.

Jan 1, 2010

By Liming Yuan

In order to reduce fire hazards caused by spontaneous combustion in longwall gob areas, a computational fluid dynamics (CFD) study is being conducted by National Institute for Occupational Safety and Health (NIOSH) to simulate the spontaneous heating of coal in longwall gob areas. A CFD model was first developed to model the spontaneous heating process in a two longwall panel district using a bleeder ventilation system with a stationary longwall face. The spontaneous heating is modeled as the low-temperature oxidation of coal in the gob using kinetic data obtained from previous laboratory-scale spontaneous combustion studies. Heat generated from coal oxidation is dissipated by convection and conduction, while oxygen and oxidation products are transported by convection and diffusion. CFD simulations were then conducted to model the spontaneous heating in longwall gob area with a bleederless ventilation system. A single longwall panel with a bleederless ventilation system was simulated. The effect of gob permeability on the spontaneous heating was also investigated.

Jan 1, 2009

By Jack E. Fraley

The Bureau of Mines has successfully developed and tested a machine for spraying sealant onto coal mine roof and ribs. Dry material is transported pneumatically to a water-adding nozzle designed to provide dust-free spraying while being nonplugging and self-cleaning. The machine is self-cleaning, 35 inches in height, and capable of applying l/2-inch-thick coatings at over 1,000 ft2/hr.

Jan 1, 1978

By Robert D. Thomson

Sheet mica is an important material in the manufacture of electronic and electrical equipment. Large quantities are consumed each year as an essential component in generators, transformers, radios, television sets, radar, electric lighting equipment, and electrical appliances. The nature, structural imperfections, and impurities determine to a great degree the usefulness of sheet mica. Proper processing and classification add greatly to its market value. This report is designed to assist producers in understanding the complexities of marketing muscovite sheet mica. ACKNOWLEDGMENTS Special acknowledgment is due S. A. Montague, of Spruce Pine Mica Co. and G. A. Purcell, mica consultant, General Services Administration, for their critical review and many helpful suggestions in the preparation of thin report. Assistance from other industry and Government representatives is acknowledged with thanks.

Jan 1, 1955

By Thomas E. Marshall, Patrick A. Kinek, Gerald L. Finfinger

The purpose of this investigation was to evaluate the integrity of the existing shutoff valves and actuators used under high-temperature conditions in the Bureau of Mines' horizontal borehole methane drainage pipe- line system and to determine the potential for improvement in the system. In the field tests, both fire-safe ball valves and standard brass ball valves were initially subjected to a 30-min pan fire without thermal protection. Neither valve could maintain line pressure beyond 11 min in a fire that reached temperatures between 500° and 700° C. Based on the test results, it was concluded that the brass ball valve used in the Bureau's methane drainage pipeline system can be retrofitted with an inexpensive "fire bag" to substantially increase its integrity under mine fire conditions.

Jan 1, 1986

By E. H. Denny

"Reduction of mine accidents appears to depend upon essentially the same fundamentals, whether considered from the viewpoint of the mine operator, miner, State mine inspector, or safety engineer. Conditions of mine operation with respect to safety are governed in most States by a mining law, usually somewhat general in its provisions but more specific than laws dealing with other industries, Methods of mining development and practice evolved through experience have been handed down from generation to generation; many of these are intended to avoid injury to men and also loss of property. To carry out the intent of these bases of law and experience relating to safety supplemental measures and conditions are necessary. Among these may be: (1) Planned safety rules adapted to the mine and compliance by both officials and Miners with such of these rules as pertain to their work; (2) a supervisory force adequate and competent to ¬administer the mining laws and safety rules; (3) discipline adequate to secure compliance with safety measures; (4) safeguards against mechanical, electrical, falling, and other hazards; (5) mining operations planned with respect to safety of workers; (6) an active safety organization of officials and employees; (7) education of officials and employees in safety practices; and (8) an active sustained interest in safety by management and employees.This paper presents the viewpoint of the safety engineer, though a safety engineer connected with a specific mine or group of mines would be in a better position than the writer to present the industrial engineer's thought. The application of the mine safety fundamentals just outlined will be given consideration from observations of methods used by safety engineers and supervisors.The term ""safety engineer"" includes men of various duties, various degrees of experience, and various authority. Depending upon the size of the operation or the interest of the management in safety, the safety engineer may have accident prevention as his sole duty; he may be the head of a sizable safety organization; or he may be in part a claim agent; a statistician compiling figures for the enlightenment of the company, the public, or a mining institute meeting; a surveyor who must convince the miner that his scale of 10/10 equals 1 foot does not defraud the miner of 6 inches to every yard measured; or he may be by heaven¬ly gift an orator capable of assuring the employees that ""all's right with the world""; he may be a young engineer gaining, experience while checking the observance of company rules and investigating accidents; or he may have the physical ills frequently resulting from several decades of mining experience and instead of a pension, the position of safety engineer has fallen to his lot. He may have mine-operating authority to correct immediately a dangerous condition or practice or he may have his recommendations officially disregarded at the monthly meeting or when the bottom of the desk basket is reached. He is likely to find that his viewpoint on accident reduction is considered unsound today because of youth and inexperience and unsound later because of old age and senility. He is likely to find the easiest course to be that of attributing to Providence and the carelessness of the worker the mishaps that result in the removal of a man to the hospital or the morgue."

Dec 1, 1936

By Oliver Bowles

Wire saws have been used for many years in European travertine, marble, and slate quarries. This method of sawing found very limited use in America until 1927 when it was accepted as standard equipment in elate quarries in Pennsylvania where it has been remarkably successful. Details of its operation in slate have been published in a recent bureau report.3 The very limited extent to which the wire saw has been employed in limestone and marble quarries in the United States and the seeming lack of interest even in experimental work to determine its advantages are difficult to explain in vied of its wide use in cutting similar rocks in Europe and its unquestionable advantages in sewing slate in America. In order to encourage improvement in quarry practice the United States Bureau of Mines has endeavored to obtain information as to the extent to which wire saws are used in Europe together with data on the rate and cost of sawing. The information at hand is by no means complete either in territory covered or in details of operation; it nevertheless brings out certain significant features that may be of interest and advantage to quarrymen in the United States.

Jan 1, 1931

By Van E. Shaw

Fusion of an 86-percent euxenite concentrate with ammonium sulfate was investigated by the Bureau of Mines. Reaction for 4 hours at 400° C results in conversion of both the rare-earth elements and the titanium-columbium components to water-soluble compounds. Similar results are obtained with ammonium bisulfate. Stirring the fusion mass decreases the reaction time substantially. Alternatively, treating the fusion product with a 3-hour, 650° C calcining step renders the non-rare-earth constituents insoluble, thereby allowing selective leaching of a pure rare-earth fraction with an overall yield of 97 percent.

Jan 1, 1967

Lower workers' dust exposures during bag stacking while ergonomically improving the bag stacking process. Approach Install a new pallet loading dust control system which uses a push-pull ventilation technique along with a hydraulic lift table to control the pallet loading height throughout the entire loading cycle. How It Works A low-volume, high-velocity blower system operating at approximately at 120 cfm blows a stream of air over the top layer of bags on the pallet. The blower system is composed of two 3-inch air jets (approximately 1,200-ft/min velocity) directed toward an exhaust system on the opposite side of the pallet. As these air jets travel across the pallet, they en-train dust generated during bag stacking. The dust laden air is then captured by the exhaust ventilation system which draws approximately 2,500 cfm through an exhaust hood on the opposite side of the pallet.

Jan 1, 1989

By Eric G. Zahl, John P. Dunford, Hamid Maleki

Coal bumps are influenced by geologic conditions, the geometric design of coal mine excavations, and the sequence and rate of extraction. Researchers from private industry and government agencies around the world have studied mechanisms of violent failure and have identified individual factors that contribute to coal bumps. To develop predictive tools for assessing coal bump potential, the authors initiated a comprehensive study using information from 25 case studies undertaken in U.S. mines. Multiple linear regression and numerical modeling analyses of geological and mining conditions were used to identify the most significant factors contributing to stress bumps in coal mines. Twenty-five factors were considered initially, including mechanical properties of strata, stress fields, face and pillar factors of safety, joint spacings, mining methods, and stress gradients. In situ strength was estimated in 12 coal seams where uniaxial compressive strength exceeded 2,000 psi. Allowances were made for favorable local yielding characteristics of mine roof and floor in reducing damage severity. Pillar and face factors of safety were calculated using displacement-discontinuity methods for specific geometries. This work identified the most important variables contributing to coal bumps. These are (1) mechanical properties of strata, including local yield characteristics of a mine roof and floor, (2) gate pillar factors of safety, (3) roof beam thickness, joint spacing, and stiffness characteristics, which influence released energy,(4) stress gradients associated with the approach of mining to areas of higher stress concentrations, and (5) the mining method. By combining the strength of both analytical and statistical methods, new capabilities were developed for predicting coal bump potential and for building confidence intervals on expected damage.

Jan 5, 1999

By James R. FitzSimmons

This report describes an instrument developed by the Bureau of Mines as an improved device for examining roof rock in bolt holes. The unit consists of a commercially available fiberoptic unit adapted for use as a flexible stratascope. Field testing in both metal and coal mines has shown the instrument can be easily transported and used by a single operator. The size and flexibility of the instrument eliminate the need for specially drilled holes.

Jan 1, 1979