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By R. H. Sprute

The Federal Bureau of Mines conducted full-scale field tests in electro-kinetic dewatering and consolidation of slimes in cooperation with the Hecla Mining Co. at two of the firm's underground mines in north Idaho. To test the technique on new deposits, 4,000 ft3 of slimes from a collection sump, pumped into a watertight stope equipped with electrodes, were treated in two steps. Immediately after placement, direct current was applied using a floating electrode to hasten settlement of suspended fine particles. After removal of clarified water, the residue was further dewatered and hardened with electrokinetic treatment. In 25 hours, the material had become firm and dense with a surface capable of supporting workmen. In testing old deposits, 10,000 ft3 of slimes, placed in an unused tail drift 10 to 12 months previously, were treated. This material was sufficiently consolidated by electrokinetics to allow its removal from the mine with standard ore-handling equipment. In both tests, electrokinetic treatment densified slimes in a relatively short time with moderate power consumption.

Jan 1, 1976

By H. W. St. Clair

In about 1930, Degussa applied for a patent on a process for the of oxides, carbides, sulfides, and other nonmetallic impurities by filtration in the molter state. The filtering media listed were wire screen, coke, and ceramic materials, and quartz. It was also suggested that filtration might be combined with chemical reaction between the metal and the filter medium or that might be added to the system. No patent was granted on the general scheme, but several years later a patent was granted on a continuous process purification of crude light metals, especially or alkali earth and their alloys. The melt was stirred at 1 temperature at which the impurities (such as oxides and salts) remained solid and the metal was drawn through a filter tube. The impurities collected under the filter and were removed by a screw conveyor. Crude sodium was purified by this process in Degussa's Knapsack plant. During the last war, when the refining of scrap became a very urgent Problem in Germany, experimental investigations were extended to separation of other metals and metallic compounds by filtration. Preliminary experiments seemed to confirm the opinion of Dr. L. Weiss that the principles of wet chemical filtration might be applied to a great extent in the purification of metal and alloys.

Jan 1, 1949

By A. J. Kraemer

This paper is the second and concluding report of the results of the twenty-fourth semiannual survey made by the Bureau of Mines of motor gasoline marketed in the United states. The first report on this 1931 survey gave the results of the examination of the gasoline samples in accordance with the new Federal specification for United States Government Motor Gasoline. The present paper reports results of the examination of the gasolines for color, doctor test gravity, end point, per cent recovered copper-dish gum, and steam-oven gum. The retail price and the tax at the time each sample was taken are also reported.

Jan 1, 1932

By J. R. Thoenen

The objective of this circular is threefold: First, to describe briefly the various modes of occurrence of sand and gravel. Second, to emphasize the need for adequate prospect¬ ing and exploration prior to the expenditure of funds for development and plant construction. Third, to describe various methods of prospecting and exploration and their application to the several modes of occurrence of sand and gravel. Sand and gravel may be found in nearly every county or township in the United States. Commercial deposits, however, are by no means so widespread. The introduction of concrete and the consequent impetus given to consumption of gravel and sand aggregates has seriously depleted deposits in some congested areas. Increasing re¬ strictions in the specification requirements for marketing sands and gravels have further narrowed the economic areas. On the other hand, the combination of increasing transportation costs and decreasing selling prices has forced the decentralization of gravel production. As a result smaller, intermittently operated, and widely scattered portable or semiportable unit plants have been encroaching on the territory formerly supplied from centrally located pits with large tr.atment plants. Generally speaking, the small portable plant can not produce any great variety of ma¬ terials to as exacting specifications nor as economically as the large permanent plant.

Dec 1, 1932

By A. J. Kraemer

The twenty-fourth of a series of semiannual surveys pertaining to motor gasoline marketed in the United States was made by the Bureau of Mines in August, 1931. The first part of a report giving the results of that survey as they pertain to specification data is given in this paper. A companion report, Part II, is in preparation and will discuss the results of other determinations made on the samples, including octane number ratings on the individual samples (to be made by the Bureau of Standards) and results of the determination of gravity, color, doctor test, and "gum" content by the copper dish method and the Bureau of Mines steam-oven method. The retail price and the tax at the time each sample was taken will also be reported.

Jan 1, 1932

By Robert L. Lagace

This final report documents the work done by Arthur D. Little, Inc. (ADL) on behalf of the U.S. Bureau of Mines, Pittsburgh Mining and Safety Research Center (PMSRC), on Contract R0122026 (which began in August of 1971). Under this contract ADI provided technical assistance to the Bureau on a task basis on virtually all aspects of the Bureau's programs related to present and planned emergency and operational communications and miner location systems for underground coal mines. The work consisted of independent investigations, analyses, experiments, breadboard and prototype hardware development, workshops and technology transfer seminars on mine communications, and on-going evaluations and guidance related to the Bureau's contracted programs on electromagnetic noise, mine communications systems, and trapped miner location. This final report documents the work in two volumes, Volume I, "Emergency and Operational Mine Communications," and Volume II, "Seismic Detection and Location of Isolated Miners." The Tables of Contents of both Volumes are included in each Volume. Phase I of the contract was devoted to performing an in-depth assessment of electromagnetic noise measurements taken by several contractors and other investigators, and then defining a new noise measurement program and instrumentation system tailored to obtain the necessary but missing noise data. These data are required for use in the design of new emergency and operational communication systems. This work, and the follow-on coordination and guidance activities of ADL on this noise measurement program in subsequent phases of the contract, are treated in Part One of Volume I.

Jan 1, 1974

By Charles A. Sorrell

This Bureau of Mines publication reviews the structural characteristics of crystalline phases and phase equilibria data for the system NaC1-KC1-AlC13-NaF-KF-AlF3, which encompasses a large number of molten salt fluxes currently used in aluminum recycling. Its purpose is to provide guidelines for research into the relationships between molten salt compositions and their physical properties, notably vapor pressures, densities, surface tensions, and viscosities, knowledge of which is essential to maximizing fluxing efficiencies and metal recovery and minimizing hazardous emissions and disposal problems. In addition, this report describes experimental determinations of sub-solidus compatibility relationships in the system, which is of the quaternary reciprocal type, containing 12 different stable 4-phase assemblages in the solid state. The compatibility diagram serves to define the important compositional planes across which important changes in properties are likely to occur.

Jan 1, 1986

By Austin Gudmundsen

"The smoke nuisance, like many other undesirable and longstanding features in our present civilization, is still with us. On reviewing the situation we are astonished to find no authentic record of a major smoke-abatement campaign that has succeeded in eliminating a smoke nuisance, in spite of the fact that the problem has been with us since the use of bituminous coal began. We might well ask ourselves where the trouble lies; is the problem impossible of solution? We can not blame the average citizen for harboring this thought as a conviction. He has been urged for so long but sees so little evidence of progress. He has repeatedly been assured by the scientist and the engineer in most convincing terms that smoke. is unnecessary, that it can be avoided; small wonder is it that he is beginning to distrust so-called authority on the subject.On the other hand, the scientist and engineer are entirely within their rights. We all know that even high-volatile coal can be and is now being burned with no visible smoke. We know that even small domestic heating furnaces, with favorable conditions and with proper care, can be fired by hand without producing much smoke. And we know that when such equipment is fitted with suitable stoking devices, little or no smoke results. What, then, is the answer?Perhaps we may learn something from a critical examination of a typical smoke-abatement problem. Probably one of the most enlightening campaigns that has been waged in the United States is that of Salt Lake City, Utah; therefore, the purpose of this paper is to discuss the important aspects of this particular case."

Apr 1, 1930

By R. W. Geehan

The Bureau of Mines has been investigating deposits of critical and essential minerals in the United States since 1939. Bureau engineers made a preliminary examination of the Morefield mine early in 1943 and recommended investigation by trenching and diamond drilling, The Bureau of Mines conducted work from August to December of 1943, which indicated that the Morefield mine was a favorable location for an experimental mining program. The Bureau of Mines carried on such a program from September 1947 to March 1949. The property investigated is 30 miles southwest of Richmond in Amelia County, Va. (fig. 1). During World War II mica and beryl were shipped from the Morefield mine, but after the high prices and premiums paid during the war years were not available the mine was closed.

Jan 1, 1953

By L. D. Schmidt

Now that the war is over, there is a great revival in popular demand to decrease pollution of the atmosphere in our cities. Great cities, such as Pittsburgh, are starting to enforce laws against violators of smoke ordinances. The substitution of low-temperature coke for bituminous coal in household heating is a most promising field for helping to eliminate the smoke nuisance. This Information Circular is written to assist in the very worth-while effort to reduce atmospheric pollution. Herein are de- scribed recent German developments in the production of low-temperature coke. Operating and cost data are given on German commercial-scale low- temperature carbonization plants.

Feb 1, 1947

By Irving Hartmann

As part of the continuing effort by the Bureau of Mines to promote mine safety, research work is being conducted at the Experimental coal mine, Bruceton, Pa., on the prevention of coal-mine explosions and on other mine-safety problems. The principal subjects studied during the past 2 years are briefly described in this paper. Although at present these problems are relevant particularly to the mine layout and to high-speed mining practices in numerous American coal mines, it is hoped that the findings will prove interesting and useful also to our European research colleagues. Some of the investigations treated here will be presented in greater detail in forthcoming Bureau of Mines reports. 1. UNDERGROUND STORAGE OF COAL CUTTINGS The seams in mist American bituminous-coal mines are undercut, shear-cut, or top-cut before blasting. The cuttings arc generally loaded out with the balance of the coal. However, in some mines it is not economical to load and remove cuttings from the mine. This applies especially if the cut section of the seam is of appreciably lower grade than the rest of the coal, or if the cut is made partly into an adjacent stratum that is high in incombustible content. In such mines the cuttings are sometimes stored in random heaps in rooms or other areas, along the ribs of mine entries, or in layers on the floor of rooms or entries.

Jan 1, 1956

By Fred A. Williams

The cause of many deaths and extensive property damage in coal mines resulting from explosions and mine fires has been directly attributable to electric cable failures (including splice failures). The Federal Bureau of Mines data show that out of 355 underground coal mine fires investigated from July 1952 to January 1960, 103 (29 percent) were directly related to trailing cables. These cable failures resulted in the death of 7 men and injuries to 37 others. These potential hazards have become greater, obviously, through the widespread adoption of mechanized mining methods with electric-driven machinery powered through trailing cables according to Young,4 68.1 percent of the total bituminous and lignite production of the United States was mined underground in 1959. About 85 percent of this production was attained by mechanized loading methods. A large majority of the mines using the hand- loading methods also used equipment with trailing cables such as cutting machines, drills, and gathering locomotives. The problem of minimizing the loss of life, resources, and equipment from cable failures should be of concern to the management of all coal mines. It would be misleading to imply that no consideration has been given to the problem and its associated hazards. Through research cable manufacturers have endeavored to develop trailing cables that will withstand the severe service imposed by underground mining conditions. Technical research groups have undertaken studies for determining improved procedure and materials for field splices. Coal companies have instituted cable maintenance programs with a view toward the reduction of cable failures and consequent improvement in safety and efficiency of operations. Safety agencies are alert to unsatisfactory cable handling practices, poor workmanship in field splicing, mechanical

Jan 1, 1962

By N. E. Hanna

The current list of permissible explosives includes 124 different brands. Fifteen of these are gelatinous, and the rest are the more commonly used granular ammonium nitrate type. Their rates of detonation range from 1,300 to 5,600 meters per second, and the weights of 1-1/4 x 8-inch cartridges range from 86 to 244 grams. The list of permissible blasting devices includes 1 Cobra, 2 Hydrox, and 9 Cardox models. All of these devices are based on discharge of high-pressure gas from a pressurized shell in a shothole. INTRODUCTION To be approved for use in underground coal mines in the United States, explosives and blasting devices must pass certain schedule tests prescribed by the Bureau of Mines. The explosives listed here were tested under Schedule 1-G,3 which has since been replaced by Schedule 1-H;4 the blasting devices were tested under Schedule 26A.5

Jan 1, 1962

By Maurice E. Bailey

The purpose of this study is to determine worker acceptance of modified mine equipment at various intervals during a twelve month period. A survey instrument was administered to the workers by two experienced miners in four interviews. All four interviews showed a significant positive response to all modifications, except the small size of the cab of the shuttle car; however, the small size produced significant negative responses with respect to comfort in each of the four interviews. Initially, (interviews one and two), there were significant negative responses with respect to manufacturer receptivity to operator suggestions and program management follow-through on operator suggestions; however, the third and fourth interviews showed no significant negative responses with respect to these items. Likewise, there were significant neutral responses in the first two interviews; however, the third and fourth interviews showed no significant neutral responses with respect to these items.

Jan 1, 1975

By Bureau of Mines Staff

Coal research and related activities in 1964 by the Bureau of Mines resulted in many advances in the production, preparation, and utilization of this valuable natural resource. Mining research during the year was marked by work on hydraulic mining, coalbed degasification, mine drainage control, mine sealing, strip-mine rehabilitation, and quenching of mine-refuse fires. Bureau research continued to produce information leading to increased safety in underground mining. Such research included roof and rib control via bolting and bonding, pressure monitoring of coal and mine rock during mining operations, and development of safety devices for detecting conditions leading to roof falls. Other safety work was continued on methane detectors, coal-dust suppression, and mine venti lation equipment and techniques. Mine explosion and explosives research, mine equipment and materials, safety rule modernization, and safety education and training of mine workmen were continued. Coal storage and preparation work in 1964 ranged from freezeproofing of lignite for rail shipment, through washability studies of coals and washing equipment, to research on new ways to remove ash and sulfur from coal. Electric power production, which ,accounts for a major portion of the market for coal, received further study. Unique power generation systems, inc luding coal-burning gas turbine and megnetohydrodynamic generators, were intensively investigated. Conventional power systems were improved through continuation of work on furnace performance, powerplant stack gas purification, and engineering and boiler water service.

Jun 1, 1965

By C. W. Sill

[In the original Norris and Fay method for determining selenium, selenious acid is reduced by an excess of standard thicsulfate in accordance with the following reaction: H2Se03 + 4Na2S203 + 4HC1 = Na2SeS406 + Na2S406 + 4NaC1 + X20. (1) The excess thiosutfate is then back-titrated with standard iodine solution. The disadvantages of ouch a method are obvious. On an unknown sample, the quantity of thiosutfate required would be difficult to determine; a definite excess is required, but large back titrations would be undesirable. Inasmuch as thiosulfate is decomposed by acid, considerable error may be introduced in this method, the amount depending on the acidity, temperature, concentration of excess thiosulfate, duration of contact between thiosulfate and acid, and other factors, In a critical study of the Norris and Fay method, Coleman and McCrosky3/ show that the method is accurate to less than .1 part per thousand if the excess of this sulfate Is not greater than 5 ml. of 0.1 N solution (in 1.0 ml. of 0.x4 N sulfuric acid) whether the titration is made at 0° or 20°C. A greater excess produced unsatisfactory values at either temperature. Coleman and McCrosky regulated the excess thiosulfate by adding 5-ml. portions of thiosulfate solution followed by the addition of 1 to 3 drops of 2.5 percent potassium iodide in the presence of starch. If a starch-iodine blue color formed locally around the drops of potassium Iodide, the reduction of selenious acid was not complete. On stirring the solution, the local blue color fades and another 5-ml. portion of thiosulfate is added. When addition of potassium iodide fails to produce a local blue color, reduction of selenious acid is complete, and the excess thiosulfate is then back-titrated with standard Iodine solution. The number of equivalents involved in the reduction of selenious acid by either thiosulfate or iodide is the same, and therefore no correction need be made for the potassium iodide. This procedure is much better than the original Norris-Fay titration, but acidity and time would stilt be rather critical factors subject to variation with individual technique. Also, the method still requires the lose of two standard solutions, a rather undesirable factor from the standpoint of routine application.]

Jan 1, 1954

By S. S. M. Chan

The Bureau of Mines has investigated the structural aspects of shafts and support systems using the finite-element technique. In situ field measurements in deep, vein-type metal mines show that rock stresses are often higher in the horizontal direction than the vertical, and unequal in the horizontal plane. These data and laboratory and field-determined physical properties were used as input to analytical studies. Various design and construction parameters were investigated to deter-mine the effect on shaft stability. Rectangular shafts were studied in detail to determine the effects of applied stress ratio, shaft orientation and dimension, influence of interbedded quartzite and argillite, and rock fracturing. Various support systems were analyzed, including concrete lining, timber, and steel sets. Circular configurations were investigated to evaluate yield zones and liner thickness. Elliptical shafts and time effects were briefly evaluated to illustrate shape and time effects and demonstrate the methodology. It is shown that the magnitude, direction, and ratio of applied stress and rock mass anisotropy are keys to determining shaft stability. A realistic conceptual framework was developed with which to examine the rock and support interaction in deep mine shafts. Structural analysis techniques overcome some of the historical difficulties with shaft de-sign by defining the field data requirements and structural sensitivity of various design and construction parameters.

Jan 1, 1985

By R. A. Friedel

THE UTILIZATION by the Bureau of Mines of infrared and ultraviolet-visible spectrometry in connection with coal research has led to some basic improvements in methods, including a calibration method, a quantitative assessment of infrared spectral energy sources, and the development and perfection of infrared filters and cells. The adoption of a micropipet method to flush organic samples into absorption cells permits the investigation of vapors from organic liquids and the identification of volatile organic compounds. The spectral method has been used to investigate the infrared spectra of metal chelates, the charge-transfer complexing properties of aniline and nitrobenzene, an infrared method for determining the presence of methane in coal-mine air that has been adopted for use in enforcing the regulations of the National Coal Mine Safety Act, and atmospheric pollution including smog and odor-causing oxidation and decomposition of organic materials. Correlation of spectra and structure of organic compounds, particularly aromatics, was studied.

Jan 1, 1966

By R. G. Gürtunca

Over the past century coal miner safety and health has seen tremendous improvements, the fatality and injury rates continue to decrease while productivity continues to increase. Many of the hazards that plagued miners in the past, such as coal bumps, methane and coal dust explosions, ground fall accidents and health issues have been significantly reduced. The contribution of NIOSH research includes products for prevention and survival of mine fires, methane control measures, design procedure for underground coal mines, methods for excavation surface controls, methods and procedures for blasting, laser usage in underground mines and prevention of electrocution from overhead power lines that have reduced accidents and injuries in underground coal mines. Health research has produced products such as the personal dust monitor, noise abating technologies and ergonomic solutions for equipment operators. Research priorities at NIOSH are set by considering surveillance statistics, stakeholder inputs and loss control principles. Future research in coal mining is directed towards respiratory diseases, noise induced hearing loss, repetitive musculoskeletal injuries, traumatic injuries, falls of ground and mine disasters. The recent spate of accidents in coal mines resulted in the Miner Act of 2006 which includes a specific role for NIOSH in future mine safety research and development. The mine safety achievements in the USA reflect the commitment of industry, labour, government and research organizations to improving the safety of the mine worker.

By H. J. Coleman

Knowledge of the types of naturally occurring sulfur compounds in petroleum is of both theoretical and practical interest to petroleum chemists and geologists. This knowledge has been extended by the identification of 77 sulfur compounds, including 36 thiols, 23 chain sulfides, and 18 cyclic sulfides in a 111° to 150° C boiling range distillate of Wasson, Texas, crude oil. The characterization procedure used in separating and identifying these compounds included isothermal distillation, vacuum fractionation, liquid-solid chromatography (alumina adsorption), chemical treatment, gas-liquid chromatography, microdesulfurization, and infrared analysis. The procedural steps described represent a systematic method of sulfur compound analysis considered applicable for determining the nature and concentration of the sulfur constituents present in any straight-run petroleum distillate of the above-boiling range.

Jan 1, 1966