Search Documents

By David E. Kaslow

In sampling dust laden air by drawing the medium into an inlet, some larger particles fail to follow the air and a true sample is not obtained. Inertia prevents particles from accelerating with the air as well as from turning sharp bends; also the particles' weight causes them to fall relative to the air. An analytic solution to the sampling efficiency calculation by Levin gives particle paths and sampling efficiencies for various particle sizes when the inlet can be treated as a point sink. However, the flow field in the neighborhood of an aspirating tube is quite different from a point sink flow. Employing Levin's solution in the outer field, trajectories in actual flow fields have been calculated by computer to locate the critical trajectories separating the entering particles I paths from those paths where the particles hit the tube wall or escape. Sampling efficiencies are presented in terms of 3 variables--a dimensionless particle size coefficient, a dimensionless orifice size coefficient and the tube orientation--for the no-wind case. Over most of the range of sampling conditions, the Stokes drag law can be used and dependence on the variable--particle Reynolds number--can be ignored. A procedure for achieving maximum efficiency in design of a sampler is proposed. Whether these results apply when typical room-sized eddies constitute the ?calm air? environment is not known.

Jan 1, 1974

By D. Bienstock

As part of the development of the hot-carbonate scrubbing process by the Bureau of Mines, the corrosion rates of steel in boiling solutions of potassium carbonate saturated with carbon dioxide and hydrogen sulfide were determined, and the effectiveness of various inhibitors was evaluated by Bureau researchers. The highly corrosive solution of carbonate saturated with carbon dioxide can be inhibited with a 0.2-percent concentration of either potassium chromate or sodium metavanadate. Solutions of carbonate saturated with carbon dioxide and hydrogen sulfide are mildly corrosive, 0.01 inch per year. Complete absence of corrosion is obtained with 0.2 percent sodium metavanadate or 0.15 percent vanadium pentoxide. Oxidizing inhibitors such as potassium chromate are destroyed in the alkaline sulfide mixture, N-alkyl trimethylene diamines, at a concentration of 0.1 percent, lower the corrosion rate to about 0.005. Sodium metasilicate, at a concentration of 0.6 percent, completely inhibits the corrosion but may deposit free silica in the system. Commercial cladding materials such as the epoxy coatings also prevent corrosion.

Jan 1, 1962

By D. Harrington

Probably over 95 percent of the coal production of the United States depends upon the use of explosives before it can be placed in the railroad car at the mine, and up to the present time it has been impossible to obtain Pry kind of practicable explosive that isn't dangerous unless handled carefully. In other words, no "foolproof" explosives have been found to date and inspection of the accident records of the coal mines of this country indicates that the use of explosives in coal mines has taken a sad toll of lives. ACCIDENTS PROM EXPLOSIVES IN COAL MATES Of the 2,000 to 2,500 persons killed annually in the coal mines if the United States, 100 to 125 have been killed from explosives without an explosion of gas or dust; these accidents have been due to misfires, hangfires, premature blasts, or accidental setting off of explosives through carelessness or otherwise (but chiefly through carelessness in some form). In this type of accident the flame character of the explosive is not necessarily involved, although an unexpected or premature blast is initiated much more easily with black blasting powder, which has a long flame, than with a permissible explosive, which has a flame much shorter and of briefer duration. By far the greater number of such accidents are caused by black blasting powder or dynamite rather than by permissible explosive.

Jan 1, 1936

By Richard L. Rains

The Bureau of Mines made a study of mines and prospects of the Benton Range RARE II area (No. 5056), Mono County, California in October and November 1980. The study area is west of Owens Valley and 30 mi (40 km) north of Bishop, California. The mineral deposits were evaluated by examination of mines, prospects, and mining claims by the Bureau of Mines. Geological, geochemical, and geophysical studies were conducted by the Geological Survey. The principal mineral commodities of the Benton Range RARE II area are gold and silver but tungsten deposits may also extend into the area. Properties with resources are listed in table 1; their locations are shown on figure 1.

Jan 1, 1982

It is not uncommon to find large quantities of combustible materials in underground metal and non-metal mines. Support timber is the predominant combustible material. Spontaneous combustion, welding and cutting, shorted or overloaded electrical cables and careless smoking are common ignition sources. More recently, there is increased use of diesel mobile equipment that requires fuel storage and transfer areas. Diesel fuel spillage on hot engine manifolds and motors can result in rapid flame growth and heavy smoke accumulation in a matter of seconds. In-expensive, reliable fire detection and suppression systems are available to provide early warning of fire conditions and to isolate and extinguish fires that originate in fuel storage and transfer areas. This report presents an example of how technology developed and demonstrated under Bureau of Mines Contract H0242016, Mine Shaft Fire and Smoke Protection System, may be applied to protect underground diesel fuel storage and transfer areas. The area application described in this report is a representative example only; the fire protection described includes the concepts of ? Early warning and alarm ? Isolation ? Extinguishment ? Control

Jan 1, 2011

By Fermont F. Clarke, Others, Paul Zinner

"INTRODUCTION The Edison mine comprises workings on two irregular spodumene-bearing pegmatite dikes which outcrop near the town of Keystone in the southern portion of the Black Hills of South Dakota. The Bureau of Mines conducted an investigation of the Edison mine as part of a comprehensive study of the lithium mineral-production possibilities in the Black Hills area. The work was undertaken during the Second World War, when the demand for certain lithium salts and compounds exceeded the then small productive capacity of the industry.During the course of the project, the Bureau of Mines completed 13 diamond core-drill holes, aggregating 2,114.5 feet of drilling. Twenty-six cannel samples were taken from the main Edison shaft, and 13 miscellaneous samples were obtained to permit analysis of the efficiency of phases of mining and sorting operations. Metallurgical tests were made by the Bureau of Mines to investigate the feasibility of beneficiating spodumere-bearing ores from the Edison mine. 3/"

Apr 1, 1948

REFERENCES AND FOOTNOTES 1. U.S. Department of the Interior, Office of Surface Mining. Surface Coal Mining Reclamation: 10 Years of Progress: 1977-1987. Washington, D.C. August 3, 1987.48 pp. (For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington D.C. 20402.) 2. The Rural Abandoned Mine Program (RAMP), authorized by Section 406 of SMCRA, provides for the control and prevention o f erosion and sediment damages from unreclaimed abandoned mine lands. 3. The Small Operator Assistance Program (SOAP), authorized by Section 401(b)(1) and 507(c) of SMCRA authorizes up to 10 percent of the fees collected for the Abandoned Mine Reclamation Fund to be used for technical assistance to help qualified small mine operators obtain techincal data needed for permit applications. Operators who produce fewer than 300,000 tons of coal per year are eligible for assistance. 4. OSM regulations 30 CFR 816.42 and 817.42 require water from areas distrubed by mining activities be in compliance with all applicable state and federal water-quality laws and effluent limitations for coal mining established by the U.S. Environmental Protection Agency. 5. Sourse: Abandoned Mine Lands Fee Collection System, Data from OSM-1 form. 6. Sourse: Abandoned Mine Lands Fee Collection System, Data from OSM-1 form. 7. Source: OSM Field Office Annual Reports. 8. Johnson, W. and G.C. Miller, Abandoned Coal-Mine Lands: nature, extent, and cost of reclamation. U. S. Bureau of Mines, 1979,29 pp. PHOTOGRAPHIC CREDITS Front cover, pp. i, 1, 2 bottom, 7 right, 10 bottom left, l 1 top, l l bottom right, 12 top, 13 bottom, 14 bottom right, 15,16 bottom, 17 top, 17 bottom right, 18 bottom, 19, 20 bottom, 21 top, 22, 23, 24 bottom, 25 bottom, 26 bottom left, 26 bottom right, 27, 28, 29 top, 30 bottom, 32 bottom right, 33 top, 34 top, 35 top left, 35 bottom left, 35 bottom right, 36 top, 37, top right, 37 bottom, 38 bottom, 39, 41, 42 top, 43 bottom, 44 bottom left, 44 bottom right, 45, 46, 47, and 53: Chuck Meyers, OSM. Page 2 top and center: Tony Fuhs. Page 3: John Sharkowicz, OSM. Page 6 left: North American Coal Corp. Pages 6 right, 7 left, l l bottom left, 13 top left, 13 top right, 17 bottom left, 21 bottom, 25 top left, 25 top right, 29 bottom, 30 center, 32 top, 32 bottom left, and 38 top: Bob Welch, OSM. Page 10 top left: Donald Stump, OSM. Pages 10 right, 14 top right, 14 center right, 18 top, and 44 top: Ron Hill, EPA. Page 12 bottom: Texas Utilities Co. Pages 16 top, 20 top, 24 top: Tennessee Valley Authority. Page 26 top right and 26 center left: Richard Dick, U.S. Bureau of Mines. Pages 30 top, 33 bottom left, 33 bottom right, 35 top right, 36 bottom, 37 top left, 40 top, 40 bottom, 42 bottom, 43 top left, and 43 top right: Jim Boyer, OSM. Page 31 top left, and 31 top right: Bruce Wage, Western Energy Co. Page 31 bottom: Rex Wilson, OSM. Page 34 bottom: West Virginia Division of Abandoned Mine Lands. Page 35 center: William Weist, Jr., OSM.

Jan 1, 1992

By Robert L. Lagace

The objective of this task was to perform theoretical analyses related to identifying and increasing the understanding of wireless propagation mechanisms in mines, and for predicting the performance ranges and limitations of proposed systems. This was to be achieved by building on and extending previous ADL work* and utilizing experimental data as they became available in the radio frequency bands of interest. B. TASKS Theoretical radio wave propagation investigations undertaken on this task centered on three areas. The first area dealt with extending previous UHF wireless propagation results*: to estimate the losses caused by the presence of haulage vehicles such as trains in coal mine tunnels; to estimate the propagation losses and wireless communication ranges expected along a longwall coal face tunnel; and to assess the applicability of previous analytical approximations to tunnels having reduced crossectional dimensions, such as those found in low coal and in the presence of haulage vehicles. The second area dealt with the development of a suitable propagation model to adequately explain the unexpected, highly favorable LF to MF band wireless radio wave propagation behavior experimentally observed in Consolidation Coal Co.'s Ireland mine. The third area dealt with the formulation of a model for evaluating the overall system transfer function and transmitter requirements for a hoist shaft LF communications system, taking into account the hoist rope/shaft transmission line characteristics, the cage and sheave wheel line terminations, the signal inductive couplers, and hoist shaft signal and noise data.

Jan 1, 1975

By W. R. Hardwick

This paper describes mining methods and practices of the Chino Mines Division, Kennecott Copper Corp., Grant County, N. Mex. It is one of a series being prepared by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. A similar program was conducted from 1928 to 1939, which helped to improve the efficiency of mining operations. The primary purpose of the program is to promote development and conservation of our mineral resources by disseminating technologic information on methods, practices, and related features in mining mineral deposits. It is expected that the program will: (1) Promote efficiency in operating mines; (2) assist operators and engineers in evaluating and developing new mineral deposits; (3) provide data for engineering curriculums in mining schools; and (4) furnish performance and cost data for revising engineering handbooks and for inclusion in engineering textbooks.

Jan 1, 1958

By S. J. Rodgers

MSA Research Corporation, Division of Mine Safety Appliances Company, was awarded a contract to conduct a survey of past and present methods used to control respirable dust in noncoal mines and ore processing mills. The survey covered information reported in mining journals, and U.S. Bureau of Mines Circulars, dust inspection reports, on-site evaluation of dust control methods and systems, and contact with manufacturers of dust control equipment. Both surface and underground mining operations were visited. Fifty mines and 51 processing plants were included in the survey. Dust control methods for the following types of ores or mines were studied: [ ]

Jan 1, 1974

By Douglas Ketcham, Thomas Jetzer

While the neurological and vascular aspects of Hand-Arm Vibration Syndrome (HAVS) has been generally accepted as a medical condition, the medical criteria and the clinical findings used to establish the diagnosis has been more difficult to bring to consensus. The criteria was first quantified by the Taylor-Palmear scale.1 This criteria was subsequently modified in 1986 at the 1st Stockholm Workshop2,3 to included more acceptance for the neurological effects that characterized the predominate findings in some workers. The relationship between hand-arm vibration and Carpal Tunnel Syndrome was defined in NIOSH 97-1414. While the aforementioned documents have defined the clinical entities associated with hand-arm vibration exposure, agreement on the clinical findings and test to confirm the diagnosis has be been more difficult to bring to consensus. Clinicians assessing HAVS has relied on a number of varied neurological and vascular tests. The neurological testing has focused on assessing damage to the sensory capability of the fingers for the neurological component including tests to measuring ability to sense vibration, cold or other end point finger sensor functions. However, the vascular testing has been traditionally focused on the ability to either measure vascular function or to reproduce the vascular blanching that occurs in HAVS with cold water provocation. Recent assessment of this testing in the United Kingdom Coal Miner’s study has questioned the value of this testing especially in reviews by McGeoch.5 In an attempt to provide some type of definitive testing to substantiate vascular damage from hand-arm vibration exposure, angiography is an alternative or adjunct to cold water provocation testing. The standards that have been established to predict the level, type and incidence of HAVS have been based on clinical studies and reports that have essentially been all male populations. However, the recent entry of women into more vibration intensive jobs has brought about the exposure of some women to high levels of vibration previously only previously experienced by men. However, there have been only few studies that look at HAVS in women6. Although exposed the same vibration levels, it has not been clear that the latency and type of pathology of HAVS in women will be the same as for men. The purpose of this study is to look at recent case studies of men and women exposed to jobs with high levels of hand-arm vibration with extensive clinical testing for both the neurological and vascular components of HAVS as well as other associated upper extremity conditions such as Carpal Tunnel Syndrome.

Jan 6, 2006

By John A. Kiefer

Ground fault and overcurrent protection criteria for coal mine a.c. distribution systems were examined under a Bureau of Mines funded investigation. The report begins with a literature review which discusses relaying topics including instrument transformers, ground-fault pickup methods, static relaying, and comparison of relaying techniques. A chapter on ground-fault relaying provides recommendations for maximum and minimum pickup levels as a function of maximum ground current and power system line-to-ground capacitance. Research in the area of phase overcurrent protection has resulted in a complete set of procedural recommendations for the selection and setting of overcurrent relays and current transformers, molded-case circuit breakers, and distribution system fuses in coal mine power systems. The final chapter, which discusses relay system maintenance, introduces a unique test set which was developed by KETRON and used to test the performance of relaying systems in coal mines.

Jan 1, 1980

By Charles Zahn

Direct mass spectrometric determination of alcohols in the presence of hydrocarbons has not been possible because of the similarity of hydrocarbon and alcohol mass spectra. Experiments have demonstrated that by converting the alcohols to their trimethylsilyl derivatives, characteristic mass spectra are obtained free of interference from hydrocarbon ion fragmentation. Hexa- methyldisilazane is the reagent selected for the conversion, An improved method of preparing the reagent is given, Mass spectrometric determination of alcohols as trimethylsilyl ethers now is not only possible without prior separation from other materials, but the range of the room-temperature mass spectrometer is also extended to include the C10 alcohol region. Water does not interfere because it is converted to hexamethyldisiloxane, which has its own distinctive mass spectral peak, Experience indicates that other compounds such as glycols, amines, and phenols probably could also be determined by mass spectrometry of their trimethylsilyl ethers. Studies on the similar detemination of phenols in coal oils have been started, When mass spectrometry is not available, gas-liquid chromatography of alcohols before and after their conversion to the trimethylsilyl derivatives probably could be performed. The preparation and properties of the trimethylsilyl derivatives of 23 alcohols, 2 glycols, 3 amines, and 1 mercaptan are detailed. INRODUCTION During investigations by the Bureau of Mines at the Pittsburgh Coal Research Center relative to the development of Fischer-Tropsch processes, complications were encountered in the mass spectrometric analysis of alcohols in hydrocarbon oils. The fragmentation peaks of the alcohols and the hydrocarbons were so similar that an accurate analysis was not possible, Since involved separation techniques are necessary to isolate alcohols from hydro-carbons for separate determinations, efforts were turned to the search for a

Jan 1, 1962

By Don M. Coulter

"INTRODUCTION Bauxite, in Appalachian Alabama, occurs in the Rock Run and Goshen Valley districts in Cherokee County; in Nences Creek Valley near Jacksonville; near Anniston in Calhoun County; north of Fort Payne in DeKalb County; near Ashville in St. Clair County; and near Talladega in Talladega County.In February 1942, Preston E. Cloud, Jr., assistant geologist, Federal Geological Survey, began a study of these bauxite deposits and the geology relating thereto.The Bureau of Mines established field headquarters at Piedmont, Calhoun County, in July 1942. Mineral agreements covering a total of 11,097 acres were executed with 15 landowners in the Rock Run district; 38 in the Goshen Valley district, covering 7,575.5 acres; and 3 in the Nances Creek Valley district, covering 988.5 acres. Drilling was done on the properties of 9 land¬owners in the Rock Run district, and on the property of 1 landowner each in the Goshen Valley and the Nances Creek districts. Drilling began October 26, 1942, and ceased on May 17, 1943.Power drilling was supplemented by a labor crew that drilled hand-auger holes in shallow deposits and sampled .old shafts, mines, and mine dumps.In all, 222 holes for a total of 13,250 feet were drilled. Of these holes, 88 penetrated bauxite but too low in grade to constitute ore."

Mar 1, 1948

By R. G. Warncke, J. H. East, D. Harrington

The mining industry of the United States has long been severely criti- cized because of its high rate of accident occurrence, not only as compared with other industries of the United States but also with the mining industries of other countries, particularly Europe. Statistics, often not strictly com- parable, indicate that the accident-frequency rate in all mining is currently about three times and the accident-severity rate is about seven times as great as the average for general industrial work in the United States. These fig- ures are by no means comforting to humanitarian mining men, irrespective of their status in the industry, and they constitute a challenge that certainly cannot continue to be ignored much longer. The picture becomes much darker when the above statistics are augmented with data indicating that on an exposure basis our mines (more particularly our coal mines) have accident rates two, three, or even more times as great as more or less similar mines in Europe, particularly England, Wales, Belgium, France, and Germany. The sting is alleviated to some extent by the knowledge that our coal mines produce about 4 to 5 times as much coal per man day as is produced in at least some European mines. However, all of these foreign acci- dent statistics should be analyzed carefully before we become very much con- cerned about them, because they are not strictly comparable, for several reasons, not the least of which is the fact that foreign methods of compiling or recording accident statistics often differ materially from ours. Moreover, foreign mining and other conditions are definitely dissimilar to ours in many phases, and numerous other factors affect the comparability of foreign mine- accident statistics with those of the United States. Unquestionably, it should also be taken into consideration that the accident rate of the 140,000,000 or more constituting the populace of the United States as a whole is much higher than that of any other major country in the world and is two, three, or more times the rate of the European countries that have more favor- able mine-accident rates than those of the United States (table 1). Moreover, it is significant that the mine-accident-severity rate of British mines is about six times the average accident-severity rate of the major industries of the British Isles, or but little more favorable than the comparable figures in the United States; namely, that mining has an accident severity rate about seven times the average of about 30 of the major industries of this country.

Apr 1, 1949

By Oliver Bowles

Sandstone, a widely distributed siliceous sedimentary rock, is the third most popular building stone in the United States. It is formed by the breaking down of preexisting rocks by weathering, subsequent segregation of the detrital quartz grains into discrete deposits by the sorting action of water or wind, and finally cementation of the quartz sand into a coherent rock. The homogeneity and resistance to weathering of the resultant sandstone make it suitable for exterior construction. Its excellent wearing properties explain its popularity for flagging and stair treads. However, quarrying and dressing methods and costs are adversely affected by the abrasiveness and hardness of sandstone especially as compared to limestone.

Jan 1, 1963

By Louis E. Dalverny

U.S. Bureau of Mines research to develop diagnostic methods to locate and evaluate fires in abandoned mines and waste banks and techniques to extinguish such fires was applied to an abandoned 60-acre underground bituminous coal mine (Renton, Allegheny County, PA) to locate and extinguish three separated fire zones. Mine fire diagnostics interpret changes from baseline values in subsurface pressures, temperatures, and mine gas composition under imposed pressure gradients induced by a borehole exhaust fan. The effective gas sampling area surrounding each borehole is greatly enlarged. Sampling iterations, using a "communicating" boreholes set, provide "fire signature" information for locating both heated and cold areas. Time-dependent monitoring differentiates heating and cooling periods resulting from combustion front movement and/or fire extinguishment activities. A water injection with fume exhaustion extinguishment effort involved injecting water through boreholes to quench the heated zones while exhaust fans actively removed heated gases from the mine. The technique was ineffective as implemented, primarily because of inadequate spreading of water from the injection points. The Bureau's diagnostic method determined the fire locations and the effectiveness of the water injection with fume exhaustion extinguishment technique.

Jan 1, 2010

This report is a compilation of all information obtained in accordance with the requirements of contracts S0122076 and H0232056. A series of eight coal mines were visited to determine their communications usage and requirements. Presently available equipment was surveyed and evaluated to determine its applicability to the needs of the mines. The equipment studied includes that made by the following companies: Anaconda Telecommunications Division Andrew Antenna Bendix Communications Division Collins Radio Group of Rockwell International Executone Communication and Sound Systems Gai-tronics Mine Safety Appliances Company Motorola Communications and Electronics, Inc National Mine Service Company Plessey Communications Systems Corp Pye Electronics Limited Reach Electronics Set Com Corporation Sonex Incorporated

Jan 1, 1974

By Stephen C. Tadolini, Thomas M. Barczak, Paul McKelvey

A new generation of hydraulic mine support prestressing devices has been developed. These thin-walled steel shells are machine-welded and can be inflated with water or any liquid to provide prestressing for a wide variety of roof support products ranging from Can supports to props and cable bolts. With an expansion capability of several inches, depending on the geometry and size of the unit, they can also establish roof contact eliminating the need for wooden wedges or crib blocks that are commonly employed with several standing roof support products. Capable of withstanding pressures from 1,000 to 6,000 psi, these cells are able to transfer roof loading into the support structure without rupturing. A recent development has been the addition of an inexpensive yield valve that provides control of the maximum pressure and load development on the support. This paper examines the performance capabilities of these inflatable prestressing units and the impact they have on the performance of various support systems, including an evaluation of the overall stiffness of the support system and the load control during yielding of the prestressing unit. Recommendations are made regarding the design requirements of the prestressing unit to optimize the support performance. A summary of mine applications using this technology is provided with general comments regarding their impact on ground control.

By Joseph Daniels

[Adequate supplies of suitable coal and coke are prime requisites in many industries, particularly those dealing with the utilization of mineral resources, recently interest has been focused on the possibilities of using electricity produced at Bonneville and Grand Coulee, Wash., in many electrochemical and electrometallurgical processes, in which core or some form of carbon is necessary in addition, discussion has been revived on the possibility of making iron and steel by the conventional methods employed in blast and open-hearth furnaces. The subject also is important at this time because of its relationship to industrial preparedness for national defense. A supply of coke from local sources on the Pacific coast is necessary in any program of production for strategic sufficiency of certain materials. An anal trio involving tae establishment of such industries should include detailed data on available supplies of coal, the quality and properties of the coke produced, and the technologic and economic factors involved in manufacture of echo and disposal of byproducts.]

Jan 1, 1941