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By C. J. Thompson

Two sulfur compounds--the 2,2,5-trimethyl- and the 2,2,5,5-tetramethyl derivatives of thiacyclopentane--were identified in Wilmington, Calif., crude oil, using microdesulfurization and gas-liquid chromtography techniques.

Jan 1, 1963

By F. W. Wood

The method described may be used to delineate irregularities, inclusions, porosity, or shrink holes in ingots up to 43 inches in length. Rou¬tine testing does not require technical personnel, and the equipment is easily maintained. INTRODUCTION For a number of years, the Northwest Electrodevelopment Laboratory of the Bureau of Mines, Albany, Oreg., under contract with the Atomic Energy Commission and the Naval Reactors Division of the Bureau of Ships, has studied the production of zirconium and has adopted the Kroll magnesium-reduction process3/ as the, most economical means of producing high-purity zirconium sponge in quantities commensurate with demand. Consumable-electrode arc melting4/ provides a practical means of melting the sponge without increasing the impurity content. The ultimate application for which the metal is intended requires that strict specifications be met to insure workability and maintain the nuclear properties and corrosion resistance. The control measures employed to satisfy these specifications include chemical, spectrographic, and metallographic analyses, mechanical and corrosion tests, and ultrasonic inspection of the finished ingot. The primary purpose of ultrasonic inspection is to augment the other control measures by checking the soundness of each ingot leaving the laboratory. An incidental but important function has been the revelation of information leading to better understanding of the arc-melting process. For example, information obtained through ultrasonic inspection relative to the occurrence and distribution of porosity in ingots has resulted in a. modification of melting practices that minimizes the occurrence.

Jan 1, 1955

By A. C. Fieldner, W. A. Selvig

Information concerning the fusibility of coal ash has become of considerable value to the consumer of coal, mainly in connection with the troublesome formation of clinker resulting from the melting of the ash constituents of the burning coal. The growing interest in such data has led the Bureau of Mines to make a general survey of the "fusing" or "softening" temperatures of the ash from coals of the United States. It is hoped that this information when used together with the large number of coal analyses published 1 by the bureau will assist the consumer of coal in comparing different coals, and in selecting the coal best adapted for his purpose.

Jan 1, 1922

By D. Harrington

Correct ventilation of underground workings whether in coal or in metal mines consists in establishing such control of air currents that the miners may work in safety, with maximum comfort and efficiency, and without impairment of health; also in controlling the air flow so that the mine workings may at ordinary times be kept reasonably free of harmful gases or dusts, and so that in time of emergency, as when a fire or an explosion occurs, there may with minimum delay be maintained as much or as little air flow as is desired throughout the mine in its entirety or in certain parts of the mine. Control of air flow is the essential point of any mine ventilating system, and is obtained only by the installation of mechanically operated fans, and other ventilating devices such as doors; overcasts, regulators, etc. Every mine, large or small, coal or metal, should from the outset be equipped with a fan. Much has been written about natural ventilation, and many claims have been made that in specific mines or parts of mines there is sufficient natural air flow. As a matter of fact, there are actually very few if any mines, coal or metal, where natural ventilation creates atmospheres anything like adequately safe or healthful for underground workers even at ordinary times or under ordinary. conditions; and at the time of a fire or an explosion mines depending upon natural ventilation are practically helpless, and are decidedly dangerous for the unfortunates forced to be in them either at the time of the disaster or afterwards when trying to handle conditions arising from the emergency.

Jan 1, 1929

By S. R. B. Cooke, J. Bruce Clemmer, F. P. Diener

"The limestone deposit utilized by one of the plants of the Universal Atlas Cement Co. is covered in part by a stratum of cherty limestone. If this overlying deposit could be utilized by removing the excess of chert economically, quarry costs could be reduced and the amount of rock economically available would be increased greatly. On account of the distribution of flint and limestone, a product fairly free of flint can be obtained until the quarry face is about 50 or 55 feet high. As the face is worked farther back into the hill, the comparatively clean stone is overlain with a constantly increasing amount of high-flint limestone. If this flint remained with the limestone, there would be a prohititively high silica ratio in the finished cement; if the flinty layer were removed as overburden a very large tonnage would be handled and much good stone lost. Consequently it was felt that means should be devised for separating the flint from the limestone after it reaches the plant.The investigation was undertaken by the Mississippi Valley Experiment Station of the United States Bureau of Mines in cooperation with the Universal Atlas Cement Co. and the Missouri School of Mines and Metallurgy, Rolla, Mo.CONSIDERATION OF PROCESSESMany schemes for the separation of Minerals are based on differences in the specific gravities of the minerals to be separated. In this case the flint has a specific gravity of approximately 2.62 while the limestone averages about 2.70. This differential is not large enough to permit separation by any method based on specific gravity. Furthermore, all the limestone particles in any given sample are not alike; usually about 10 percent of them have a specific gravity the same as, or lower than, the flint."

Mar 1, 1935

By Alla D. Mah

Energies of combustion of vanadium nitride (VN) and vanadium carbide (VC) were measured. Correcting to vanadium tetroxide (V204) as the final state, the heats of combustion were ?H298.15=-118,700±100 cal/mole of vanadium nitride and ?H298.15=-240,270±360 cal/mole of vanadium carbide. With vanadium pentoxide (V205) as the final state, the heats of combustion were ?H298.15= -133.440±100 cal/mole of vanadium nitride and ?H298.15=-255,020±360 cal/mole of vanadium carbide. Combining these results with vanadium oxide data, the heats of formation obtained were ?298.15=-51,880±200 cal/mole of vanadium nitride and ?H298.15=-24,350±400 cal/mole of vanadium carbide. Heats and free energies of formation of vanadium nitride and carbide were calculated to 2,000° K.

Jan 1, 1963

By James S. Browning

The Bureau of Mines conducted laboratory batch and small-scale continuous flotation tests of weathered mica pegmatite ores from Alabama and North Carolina to determine the technical feasibility of recovering commercial-grade mica concentrates. A new anionic-catonic method was developed for recovering mica in the presence of clay slimes. In continuous tests, concentrates containing 98.1 percent mica were obtained from the Alabama pegmatite ore; the North Carolina pegmatite ore concentrates contained 97.2 percent mica. The recoveries were 83.8 and 81.6 percent, respectively.

Jan 1, 1965

By L. Cheng

This report describes a laboratory investigation of the effectiveness of low-pressure steam and a steam-water spray sequence for the collection of airborne respirable (<10 µm) coal dust. Comparison of present results to previous results obtained with water spray alone indicates that the use of steam in a steam-spray sequence increases the collection efficiency by about 14 percent over that obtained by water spray alone. However, the use of steam to collect airborne dust requires cooling the steam-dust mixture in order to achieve condensation of the steam, and steam does not appear to be an attractive approach for collecting airborne dust in underground coal mining operations.

Jan 1, 1974

By R. Clark Lantz, Charles Stanley, David E. Hinton

Morphometric examination of lung alterations following exposure to toxic and pathogenic substances is invaluable in detecting subtle changes which might otherwise be overlooked. Results, from evaluation of initial structural alterations, support and guide subsequent nonmorphological techniques and, when coupled appropriately, can lead to a better understanding of the pathogenesis of a disease. Morphometry is a technique which can be used to determine, quantitatively, the site, extent, development, and progression of a disease state. Determination of the extent of tissue and cellular involvement in the response to inhalation of silica has been performed in order to gain a better understanding of the development of fibrosis following inhalation of this toxicant. In addition, since silica has been postulated as one of the important pathogenic minerals in coal mine dust' it is important to understand the lung tissue response to silica prior to evaluating the effects of inhaled coal mine dusts. Male Syrian golden hamsters were placed in Hazelton 1000 inhalation chambers and were exposed to either filtered air (controls, n = 24) or filtered air plus 30 mg!m3 silica (Min-U-Si110,95%ofparticles < 5 um,n =24)for16hours per day, five days per week, for two weeks. Animals were returned to the animal quarters prior to subsequent tissue processing at 1, 4, and 12 weeks following exposure. This schedule was designed to allow time for the development of fibrosis. Lungs were fixed by intratracheal perfusion of ½ strength Karnovsky's fixative at a pressure of 20 cm H20 and tissues were taken for embedment and analysis at the light level. Determination of site, extent, and development of alterations was performed using a multitiered approach. Changes in large structures (airways, blood vessels) was determined prior to evaluation of changes at the septal tissue level. Data will be presented outlining the progression of changes. Results indicate the usefulness of morphometric analysis of lungs following inhalation of toxic substances in quantitatively defining the structural alterations.

Mar 1, 1989

By Eugene T. Sheridan

The 25th annual survey of the peat industry by the Bureau of Mines, United States Department of the Interior, disclosed that 79 companies produced and sold peat from 81 operations in 21 States in 1958. Peat is a carbonaceous deposit, formed under water or in a water-saturated environment from plant material. It is the first stage in the development of coal and, when properly dried, can be used as fuel. Although 98 percent (estimated) of the total world production is used for energy purposes, the status of peat in the United States is somewhat unique in that none is used for fuel, and practically all is consumed as an agricultural product, chiefly for soil improvement purposes. The domestic peat industry has expanded rapidly since World War II, and production in 1958 was 327,813 net tons valued at $3,445,767. More than one-half million ton of peat was consumed in the United State in 1958, however, as 269,096 tons was imported.

Jan 1, 1959

By I. L. Nichols

Volatilization of cesium from pollucite ore was investigated as an initial step in the production of purified cesium metal or cesium salts. High recovery of cesium and rubidium as chloride sublimates was accomplished by 2-hour roasts in a tube furnace using charges containing 1 part ore, 2 parts limestone, and 0.23 part calcium chloride. Recoveries of cesium in the sublimate product were 89.1, 92.9, and 95.2 pct, respectively, using 1,100° C and vacuum, 1,250° C with an air sweep, and 1,250° C without an air sweep. Most of the lithium, sodium, and potassium sublimed with the cesium and rubidium, but virtually none of the calcium, aluminum, and silicon in the charges was volatilized.

Jan 1, 1966

By D. B. Gawthrop

"One of the properties of an explosive, of interest to the user, is its ability to transfer detonation across an air gap to another explosive charge. This Property is of particular importance with permissible explosives used in coal mines, since they are relatively insensitive to detonation when compared to many of the commercial dynamites used in metal mining.An essential characteristic of an explosive is that it shall always be sufficiently sensitive to propagate detonation completely. An insensitive explosive constitutes a hazard because of (1) the danger of drilling into unexploded portions of charges of explosives which have partially misfired, and (2) the likelihood of a low order of detonation, or the burning, of all or part of the charge in a hole prepared for blasting. The latter condition not only usually produces large volumes of poisonous gases, but it is particularly hazardous in gassy or dusty coal mines where explosions may result.The Bureau of Mines and manufacturers of explosives determine the sensitivity of explosives to detonation over an air gap by means of a [(halved-cartridge gap test,"" for which the ends of the cartridges of explosive exposed to one another, are cut off. Since in blasting, the crimped ends remain on the cartridges used, this investigation has been made to ascertain the effect of the crimped paper ends on the distance detonation is propagated over an air gap as compared with the propagation distances obtained when the crimped-paper ends are removed."

Nov 1, 1932

By L. B. Pankratz

Heat contents, measured above 298.15° K, and derived entropy increments are presented in tabular and equation form for the two crystalline forms of zinc sulfide (sphalerite and wurtzite) and for four solid solutions of iron and zinc sulfides having the compositions Zno.,,6Fe0.302S, Zno.750Fe0.250S, Zno.650Fe0.3505, and Zno.498Feo.502S.

Jan 1, 1965

By A. B. Hooker, P. G. Guest, E. J. Gleim

"From time to time the United States Bureau of Mines has received reports of gas explosions alleged to have been caused by correctly assembled flame safety lamps. In most of the mines where the explosions occurred the lamp was in use at a working face where the velocity of the ventilating current would be relatively low. The inference has been that the lamp was correctly assembled but that the gauze became sufficiently overheated to ignite the surrounding atmosphere.As part of its routine investigation of flame safety lamps the Bureau of Mines subjects each lamp to a test in still and moving atmospheres to determine its safety. Heretofore, as long as the lam, successfully passed this and other tests no determinations as to the margin between success and failure were made; hence, in attempting to answer inquiries concerning the reported explosions it was found desirable to be able to give actual gauze temperatures as a measure of the comparative safety of lamps under various conditions. The previous laboratory tests of flame lamps in still mixtures were made in a chamber or ""gallery"" of relatively small volume where the lamps might have been subject more or less to the smothering effect of the combustion products. It was therefore decided to make a special series of tests to obtain the gauze temperatures of both bonneted and unbonneted lamps in still and low velocity mixtures, using a larger gallery to offset any smothering effect.These tests are believed to represent the first attempt at measuring gauze temperatures by means of themocouples. The results will not only be of interest but will also be helpful to many in determining the status of flame safety lamps relative to gas ignitions in mines."

Feb 1, 1929

By R. R. Schehl

The Bureau of Mines analyzed the structure of a high-grade metallurgical coke, carbonized at different temperatures in the range 500° to 1,000° C, through X-ray diffraction studies. Growth in the crystallite size with increasing coking temperature was calculated from profile analysis and compared with values obtained from the radial distribution function. The carbonization temperature appeared to have little influence upon the stack height, whereas the layer diameters more than doubled in size between 500° and 1,000° C. These results are comparable to those obtained from other studies of poorer quality cokes.

Jan 1, 1974

By R. C. Annear

This report describes open, sublevel, and shrinkage stoping at the Greenwood mine, operated by Inland Steel-Co. The iron ore mine is in Marquette County, Mich., about 6 miles southwest of Ishpeming (fig. 1). The Greenwood is one of three active underground hard-ore mines on the Marquette range, the others being the Cliffs-Shaft and the Champion mines. The operation reflects an achievement in exploiting small, difficult-to-mine hard-ore bodies lying beneath a 200-foot overburden of glacial drift, which is partly water bearing. This report can indicate only briefly the efforts of personnel in overcoming adverse conditions in mining more than 2 million tons of ore, 80 percent of which was in lump form, for open-hearth production of steel. Significant data presented include descriptions of the principal mining methods employed, sublevel and shrinkage stoping; percent aged mining costs for the entire year 1957, covering both direct mining costs and general expenses; and performance records in units of labor, power, and supplies.

Jan 1, 1960

By D. B. Gawthrop, A. Taylor, G. St. J. Ferrott

"This paper presents data obtained as part of an investigation of the explosive properties of ammonium nitrate. During the course of the work: it was found desirable to investigate the sensitizing action of nitrostarch in mixtures of ammonium nitrate containing low percentages of this material. Data were derived as to the sensitivity to decomposition by heat and the completeness of detonation and,of detonation of straight ammonium nitrate, as compared with ammonium nitrate-nitrostrarch mixtures containing 1 to 10 per cent of nitrostarch.The ammonium nitrate was a sample of coated material obtained from the salvage of amatol shells. Its analysis was as follows:"

Feb 1, 1930

By R. Hogg

"The problems of sampling particulate materials, and of characterizing the distributions of particle size and composition are reviewed. Requirements for sampling from comminution systems are discussed and a simple formula is presented for estimating the minimum sample size needed. The limitations and errors associated with the techniques available for particle size analysis are evaluated and guidelines are suggested for the selection of appropriate methods. The use of microscopic and macroscopic approaches to the characterization of particle composition are discussed.INTRODUCTIONComminution is a process of particle size reduction in which the goal is to produce a material with a specified particle size distribution from a coarser feed. In mineral processing applications, the product size distribution is often qf secondary importance to the extent to which individual mineral grams can be liberated from one another. However, due to poor understanding of the nature of the liberation process and the lack of reliable procedures for characterizing it, the actual specification is normally in terms of particle size.Particle size distribution can be regarded as the fundamental characteristic of a particulate system. The distributions of particle shape and composition among the various particle sizes present are often sufficient to define the bulk properties and behavior of the system. Description of the distributions of size; shape and composition of the different phases which may exist within individual particles is necessary to complete the picture and is especially important for predicting liberation etc., in comminution processes. It is quite obvious that · the complete characterization of real particulate systems is a formidable, if not .impossible task. Practical characterization procedures should involve ·evaluation of those characteristics which are deemed to be important and which can be measured. In comminution systems, this should ideally include the particle size distribution, the size-by-size distributions of particle composition, and as much information as can be acquired on the internal composition and structure of individual particles. In most cases, of course, we fall far short of even this rather limited goal."

Jan 1, 1988

By T. A. Sullivan

High-purity vanadium metal was prepared by electrorefining commercial vanadium in a molten sodium bromide, potassium bromide, and vanadium dibromide electrolyte. Variables investigated were operating temperature, current densities, electrolyte composition, and condition of the anode. The purity of the refined metal was in the range of 99.95 percent vana-dium. Iron and oxygen in the 50- to 250-ppm range were the only major impurities. Metal with hardness numbers of 50 to 60 in the Rockwell F scale was prepared from feed material with a Rockwell B hardness of 90. The arc-melted metal was highly ductile and could be cold-worked into sheet or foil.

Jan 1, 1965

By M. Clair Smith

The Sweetwater, Castro, Trinidad, New London, and Hilltop chromite properties are situated within an area 8 miles long and 1 mile wide between San Luis Obispo city and Morro Creek, San Luis Obiso County, Calif. Development work at this group of mines was a part of a long-range project by the Bureau of Mines to develop strategic mineral reserves in the United States in accordance with the Strategic Minerals Act of 1939. The junior author of this report participated in the preliminary examinations made in 1941 of the chromite deposits that later in the same year were the subject of more intensive investigation under the immediate supervision of the senior author. The ore occurs in lenses and kidneys in masses of dunite contained in large poridetite areas. Production has boon in the form of lump ore and concentrates from disseminated ore. Work by the Bureau of Miner included surveying, mapping, trenching, sampling, and assaying. It is summarized separately in the text under the name of each mine investigated. The report gives a brief history of the district, describer the concentrating plant of the Castro Associates, and gives detailed results on sampling and assays at the various proportion.

Jan 1, 1951