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By Sarkis G. Ampian

The Bureau of Mines has developed a method for identifying fine particles of beryl in mineral samples by preferentially staining the beryl grains. The sample is first subjected to a heated sodium hydroxide solution to etch the beryl particles, which are subsequently stained an intense blue color in a boiling alkaline solution of quinalizarin. Positive identification of beryl grains permits quantitative analyses by microscopic techniques. INTRODUCTION Beryl, a beryllium aluminum Silicate, is the principal ore mineral of beryllium. The only known commercial concentrations of this mineral are found in pegmatite dikes of granitic composition. Normally beryl is associated with muscovite mica, quartz, and the sodium-and potassium-bearing feldspars (orthoclase, microcline, and albite). Other beryllium-bearing minerals which are found occasionally in minor amounts with beryl are phenacite, a beryllium silicate, and chrysoberyl, a beryllium aluminate.

Jan 1, 1962

By S. H. Ash

"INTRODUCTION Mine fires have occurred since underground mining of minerals began, and they are still occurring. The technical literature is replete with papers relating to mine fires.Means and methods for controlling and extinguishing mine fires and preventing explosions and other accidents require the collection and analyses of samples of the atmospheres surrounding the fire. Such atmos¬pheres are complex mixtures of gases (1, 3, 4, 15, 21, 23).3/SUMMARYExperiences at mine fires (1, 3, 4, 15, 21, 23) have proved conclusively that mine-air analyses furnish the only means of judging what is going on in a mine fire area. Mine-air analyses give evidence of conditions that require immediate protection, govern the order and control the manner in which a fire is fought, show the necessity of bulkheads and establish the places to construct them, indicate whether or not a fire is being controlled or is being extinguished, and govern procedure in sealing and unsealing mine fires.It is commonly believed that danger to life and property from mine-fire atmospheres is greatest in coal mines; this is true only to the degree that the explosion hazard is greater in coal mines than in noncoal mines because of the presence of combustible gases. The problem of gas poisoning is greater in noncoal mines because of the more frequent occurrence of poisonous and innocuous gases, oftentimes the lack of controlled ventilation, and usually greater difficulties in sealing mine-fire areas. Sulfide minerals present a serious hazard in many metal-mine fires when sulfur dioxide is formed. The country rock or ore body itself may contain or be limestone, which may be calcined. Emanations of carbon dioxide are found."

Dec 1, 1950

By J. E. Pahlman

One of the goals of the Bureau of Mines is to develop metallurgical pro-cesses that conserve energy and/or that take advantage of abundant domestic energy sources. Western lignites and subbituminous coals can be used for firing pellet induration and metallization furnaces. However, the refractory linings of these furnaces must be able to withstand attack from corrosive alkali metal oxides present in the ash of many of the low-rank fossil fuels. The Bureau of Mines conducted dynamic and static slag tests on high-alumina and alumina-silica refractories to determine their resistance to lignite ash slags. The investigations showed that increased alkali content in the lignite ash caused increased corrosion and erosion of the tested refractories. The degree of corrosion decreased with increasing alumina content, with the 99-percent-alumina refractories having the highest resistance. In general, the matrix phase was attacked preferentially to the alumina grains. Also, porosity reduction and tar impregnation enhanced the corrosion and erosion resistance. The 90-to 99-percent-alumina refractories are recommended for use as furnace linings in alkali slag environments.

Jan 1, 1979

By Paul S. Lewis

Bench-scale experiment~ by the Bureau of Mines showed the gross effect of retention times ranging from 0.1 to 14.5 minutes on the conversion of high-volatile C bituminous coal to liquids and gases. The uncatalyzed coal was hydrogenated at 400°, 450°, and 538° C. and 500, 1,000, and 2,000 p.s.i.g. The percent coal conversion increased rapidly during the initial 3 minutes and asymptotically approached a maximum within 7 minutes at all conditions. Reasonably good correlations of coal conversion with time, pressure, and temperature were obtained. Temperatures up to 900° C. and retention times of about 1 minute are recommended for future experiments with the objective of producing only gaseous hydrocarbons and partially devolatilized coal suitable for use as solid fuel. The reactor contained 13 semicircular ledges, and the retention time was controlled by the rotation of scrapers which swept the coal from ledge to ledge. Only coal feeds that did not adhere to the internal mechanism could be used.

Jan 1, 1961

By J. R. Welty

High-temperature thermodynamic data have, in recent years, become increasingly important for the extractive metallurgist. The extraction of metals from their ores previously was based on trial and error methods, involving hours of testing and often costly equipment fabrication. Using thermodynamic data it is frequently possible to predict the feasibility of a proposed metallurgical process as well as the optimum operating conditions for the process with reasonable accuracy. Such predictions can save consider-able tim~ and expense. Widespread use of thermodynamic analyses has been handicapped by lack of dependable experimental data. Investigators, notably K. K. Kelley (4)4. have devoted many years to determining and compiling such data. These investigators, although prolific in their production of thermodynamic values, have been unable to meet all the needs of industry and other branches of science. This becomes obvious when one considers the aeronautical and nuclear fields, in which previously unimportant, therefore uninvestigated, substances have become of prime importance.

Jan 1, 1962

By R. H. Grau, S. B. Robertson, R. B. Krog, T. P. Mucho

Stone mines represent the highest percentage of operating underground nonmetal mines in the United States. With the introduction of stricter Diesel Particular Matter (DPM) regulations, large-opening underground room-and-pillar stone mine operators are faced with implementing one or more alternative methods to reduce concentration levels including: install and maintain an effective ventilation system; install lower DPM emission diesel engines; the adding of DPM filters. The National Institute for Occupational Safety and Health (NIOSH) is actively researching various aspects of fan and stopping designs in an effort to improve the ventilation of these mines. NIOSH has identified and further developed three alternative ventilation methods for use in large-opening underground mines: split-mine, perimeter, and unit-ventilation. This paper describes the implementation of the three methods with respect to their use in mines of various levels of development.

By J. F. Barkley

As part of the work of serving as Chairman of Subcommittee 3, Health and Industrial Requirements, of the American Society of Mechanical Engineers' Committee on Air-Pollution Controls, the author assembled the following information on accepted maximum permissible concentrations of air pollutants from the standpoints of health, damage to vegetation, damage to property, and requirements of industrial processes. A search in technical literature was made followed by direct inquiry to all State governments as to their regulations. The subcommittee membership - G. D. Clayton, senior sanitary engineer, Public Health Service, United States Department of Health, Education, and Welfare, Detroit, Mich., Dr. L. Greenburg, commissioner; Department of Air Pollution Control, New York, N.Y., Dr. M. Katz, Defence Research Chemical Laboratories, Ottawa, Ontario, Canada, and Dr. H. H. Schrenk, research director, Industrial Hygiene Foundation of America, Inc., Mellon Institute, Pittsburgh, Pa. - reviewed the information and made very helpful comments and corrections.

Jan 1, 1954

By G. H. Hopkins

Like most industries, the refining industry has in recent years been confronted with the problem of a decreased martin of profit, due both to a general lowering of prices and to rising costs. This has resulted in accelerating a program of increased efficiency an evidenced by improved methods and the installation of equipment designed to affect a number of economies hitherto regarded as unimportant. Perhaps the most important of these has been that of fuel economy for, as is not often realized, a refinery consumes about one-tenth as much fuel as it produces. A recently completed canvas., made by the Bureau of Mines for the purpose of determining the trend of fuel consumption at refineries in the United States, showed the following outstanding points, (1) a decrease in the use of oil for fuel in 1926 of approximately 4,000,000 barrels as compared with 1925; (2) a small decrease in the use of coal; (3) a material increase in the use of gas, both natural gas and refinery gas; and (4) a considerable increase in the use of petroleum coke.

Jan 1, 1927

By G. W. Reimers

Metastable pyrophoric wüstite (FexO, with x between 0.89 and 0.95) was found to be much easier to grind to colloidal state than were its stable disproportion products magnetite or iron. The grinding of polycrystalline magnetite appears to be complicated by the magnetic flocculation arising from interparticle attraction. This is superimposed on the attraction of a fluctuating electric dipole for a neighboring induced dipole. More than 85 pct of the tumbling time was saved by grinding antiferromagnetic wüstite instead of the ferrimagnetic oxide of iron (Fe304). Disproportionation of colloidal wüstite to the stable ferromagnetic and ferrimagnetic colloidal particles of alpha-iron and magnetite, respectively, was accomplished rapidly at temperatures above 250° C but below 570° C, the eutectoidal stability point of the wüstite phase.

Jan 1, 1972

By S. D. Maksimovic

The Bureau of Mines identified and evaluated major sources of quartz dust during overburden drilling at a surface coal mine, The relative contribution of each source to the total dust hazard was estimated, using personal gravimetric and instantaneous dust-sampling devices. No attempt was made to determine actual dust generation rates. The major sources of dust at the drill rig during dry drilling opera-tions were the collector dump, drill shroud leakage, and drill stem seal leakage, These sources contributed 90 pct of the respirable dust and 89 pet of the respirable quartz dust generated during drilling, The collector dump cycle (21.6 pct of total drilling time) accounted for 38 pct of the respirable dust and 41 pct of the respirable quartz dust, with peak dust concentrations reaching 68 mg/m3. Shroud and drill stem leakage contributed 28 and 24 pct of the respirable dust and 32 and 16 pct of the respirable quartz dust, respectively. A dragline and second drill rig contributed the remaining 10 pct of dust and 11 pct of quartz dust. Gravimetric dust samples collected inside the drill cab and outside, near the cab door, averaged 1.65 and 1.43 mg/m3, respectively, with 6 pct respirable quartz.

Jan 1, 1985

By Oliver Bowles

[In an endeavor to promote greater efficiency in the lime industry, the United States Bureau of Mines is preparing a series of preliminary reports dealing with particular problems of the industry. Through the circulation of these reports, it is hoped that sufficient interest may develop among lime-plant operators to prompt them to discuss with the bureau their our experiences with these problems. By such an interchange of ideas, it is believed that conclusion may be reached which will be of practical benefit to try entire industry. The first report, "Stripping problems it Limestone quarries of the Shenondoah Valley", Serial No. 2401, was issued during October, 1922. This report t is the second of the series. It is hoped that may operators will contribute additions to the information now at hand.]

Jan 1, 1922

By Sidney Katell

This report is an economic evaluation of the production of hydrogen in a continuous system by the steam oxidation of partially reduced iron oxide in a fluidized bed at 7 atmospheres using producer gas to reduce the iron oxide. The oxidation-reduction step is based on experimental data obtained by the Bureau of Mines at the Pittsburgh Coal Research Center. The estimated capital requirement for a plant producing 30 million std. c.f.d.3 of 99.8 percent purity hydrogen at a discharge pressure of 450 p.s.i.g. is $13,100,000, using January 1961 equipment cost data. Based on a 330-day operating year, the operating cost before profit and taxes with coal price as a variable is estimated to be:

Jan 1, 1962

By R. V. Lundquist

The work described in this report, part of the Bureau of Mines long-range program to develop methods of utilizing submarginal domestic sources of aluminum, was undertaken to investigate the effects of iron in the lime soda sinter process, The approximate Fe2O3 content in a sinter for maximum alumina and soda recovery was 8 to 9 percent. Fe2O3 appears to inhibit gelation, and 15.5 percent Fe2O3 produces effects similar to those produced by 1 percent sucrose. In the lime soda sinter process, aluminum silicates are sintered with limestone and soda ash to yield dicalcium silicate and sodium aluminate. The sodium aluminate is extracted by leaching in caustic solution. The solution is purified by heating in an autoclave with lime to remove silica, and alumina trihydrate is precipitated with carbon dioxide. The reactions involved in sintering and leaching are complex. A number of studies by the Bureau of Mines4-9 and others1 indicate that the iron content of sinters influenced the recovery of alumina and soda and the gelation characteristics.

Jan 1, 1962

By Michael D. Fenton

Social and political movements that had been gathering momentum over several years continued in 1993 to dramatically affect and inspire uncertainty on the global mineral industry. Privatization of government-controlled mineral industries continued throughout the world, especially in Africa, Asia, Central Eurasia, Eastern Europe, Latin America, and Western Europe. The reasons for privatization varied among regions and countries, but the trend was universal and was not expected to end soon. Regional trade blocks were being developed and expanded. The European Union (EU), the North American Free Trade Area (NAFTA), the Association of Southeast Asian Nations (ASEAN) , the Asia Pacific Economic Cooperation (APEC) , and the Latin American Southern Cone Common Market (MERCOSUR) were expected to contribute to reduced internal tariffs and increased minerals trade. Minerals consumption within the politically unstable former Soviet Union (FSU) decreased significantly without a simultaneous cutback in production, while its exports flooded the world's mineral markets. These exports into Western Europe and Japan, still in economic recession, depressed minerals and metals prices worldwide, especially for aluminum, magnesium, nickel, and potash. Increasingly restrictive environmental laws and land-access limitations in Australia, Canada, Western Europe, and the United States tended to discourage mineral resource development. However, the number of undeveloped countries in Latin America and Asia that encouraged exploration and development by revising mining and tax laws and regulations increased, thereby increasing investment opportunities for foreigners.

Jan 1, 1995

By B. E. Blair

Accelerometers of various types, velocity gages, and a displacement meter are shown to give reliable date when measuring seismic pulses generated in rock by the detonation of explosive charges. Displacement and velocity records are differentiated and shown to compare with velocity and acceleration records. Velocity and acceleration records are integrated and shown to compare with displacement and velocity records, respectively. The experimental data are shown to satisfy the scaling laws developed by dimensional analysis. Propagation laws are developed for peak amplitudes of the first pulse of displacement, velocity, and acceleration. These propagation laws are shown to be independent of the gage used to obtain the data. As a result, the usefulness of the various gage types can be extended. For example, accelerometers, because of their high frequency and amplitude limits, can be employed near the shot to measure acceleration and/or velocity (by integration), Velocity gages, because of their higher sensitivity, can be employed at relatively larger distances from the shot to measure velocity and displacement or acceleration (by integration or differentiation).

Jan 1, 1954

By Henry G. Dorsett

Dust explosion data obtained in laboratory tests by the Bureau of Mines are presented for 73 chemical compounds and mixtures, 29 drugs, 27 dyes, and 46 pesticides. Information is given on ignition temperatures of cloud and layer, minimum igniting energy, minimum explosive concentration, percent of inert dust required to prevent flame propagation, limiting oxygen concentration in the atmosphere to prevent ignition, and pressures and rates of pressure rise at dust concentrations of 0.1, 0.2, 0.5, 1.0, and 2.0 ounces per cubic foot. Explosibility indexes are computed where data are available to permit comparison of the relative explosion hazard. Variations of explosibility parameters with chemical composition are discussed. General means for minimizing the dust explosion hazard are reviewed.

Jan 1, 1968

By D. K. Dysinger

In this U.S. Bureau of Mines study, neodymium metal of 99.8 pct purity was prepared by electrolysis of Nd203 salts dissolved in a molten fluoride electrolyte. The metal was electrowon in a molten state at current efficiencies of 50 to 60 pct. Oxygen and carbon were the major impurities detected in the product. During operation of the small-scale laboratory cell, a number of technical problems including anode effect, low oxide solubility in the electrolyte, high neodymium metal solubility, reactivity of the metal with the cell materials, and back reaction of the metal with the anode gases were encountered. Approaches to improve cell operation and prospects for commercial adoption of the electrolytic production of neodymium metal are discussed.

Jan 1, 2010

By Charles L. Kimbell

While the statistical summary focuses on 1991 data, this update and outlook section draws on information available to the author as of the date of final preparation in early 1993. For all the press notoriety associated with the shift in the Near East crisis from the defensive posture of Desert Shield to the restoration of Kuwaiti sovereignty through Desert Storm, this was not the dominant event governing global economic thinking in 1991 and the first half and more of 1992. From the global perspective, the momentous political changes in the area that was the U.S.S.R. and in the smaller emerging transitional economy states of Eastern Europe will have even greater current and long-lasting effects on world mineral industry activities than the crisis in the Near East.

Jan 1, 1993

By L. B. Pankratz

The heat content above 298.15° K was determined for crystalline vanadium silicide of the composition V3Si. This substance has a minor thermal anomaly (probably a heat-capacity maximum) near 560° K; the extra heat absorption is about 50 cal/mole. The original heat-content data are presented, and smooth values of the heat content and the corresponding entropy increments are listed for the temperature range from 298.15° to 1,500° K. Equations representing the heat- content values and derived heat capacities are also included.

Jan 1, 1963

By T. W. Beck

The National Institute for Occupational Safety and Health (NIOSH) conducratory and field tests to evaluate the effectiveness of dust collector bags for reducing dust liberation and operator exposure from a roof bolter’s dust collection system. The laboratory tests evaluated the bag’s effectiveness to contain dust and the effect on canister filter loading in both a bag and bagless condition. The dust emissions from the collector’s exhaust were also measured in each condition during laboratory testing and show that nearly 100% of the test dust fed into the collector was captured by the dust bags. Loading and pressure drop on the dust collector’s canister filter is greatly decreased when using the bags, enabling longer periods of drilling without filter removal/cleaning. The field results showed that, even though dust standards were met, respirable dust in exhausted emissions was reduced around the bolter. Laboratory and field results show that benefits from use of the bags are realized in all areas of operator exposure.