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By J. B. Gayle

During the past several decades, there has been a steady increase in the number and size of experimental ovens used for carbonization research. Although many were originally intended principally for studies of coal expansion, current practice usually includes determinations of the properties of the experimental cokes. With respect to size and shatter characteristics, the cokes from the larger experimental ovens closely approximate those from duplicate charges carbonized in commercial ovens; however, they are consistently lighter and frequently less resistant to degradation by abrasive forces. To minimize these differences, some operators dry the experimental charges before carbonization. The resulting higher dry coal charge densities do, in fact, yield cokes with gravities closely approximating those produced commercially from the same coal or blend but without drying. The drying of the experimental charges may be criticized on the grounds that it represents a departure from commercial practice and may result in oxidation of the samples; for these reasons, the practice has not been universally adopted.

Jan 1, 1961

By Walter Kawa

Coals of various rank were reacted by the Bureau of Nines in plasma jets generated from argon and argon-hydrogen mixtures containing up to 33 volume-percent hydrogen. Average plasma temperatures ranged from about 3,400° to 12,000° C. Products were a solid residue and a gas containing hydrogen, methane, acetylene, diacetylene, and oxides of carbon. The highest yield of acetylene obtained with argon plasmas was 15 percent by weight of moisture- and ash-free coal. The data indicated that acetylene yields of 40 percent or higher can be obtained from the reaction of coal in argon-hydrogen plasmas, although results from these experiments could not be correlated with operating variables because of low recoveries plasma contained sufficient energy to heat the coal to temperatures as high 9,000 or 10,000° C, but complete devolatilization did not occur in any experiment.

Jan 1, 1966

By W. W. Adams

The quantity of explosives sold in the United States in January, 1931, for domestic consumption, amounted to 368,100 kegs (9,202,500 pounds) of black blasting powder, 4,610;000 pounds of permissible explosives, and 16,533,000 pounds of high explosives 'other than permissible. These figures are based on reports received by the United States Bureau of Mines, Department of Commerce, from nearly all manufacturing companies, and include an estimate of sales by several companies that do not furnish monthly reports. Reports actually received from manufacturers showed soles of 365,977 kegs of black blasting powder (consisting of 220,892 kegs of granular powder and 145,085 kegs of pellet powder), 4,687,900 pounds of permissible explosives, and 15,496,152 pounds of high explosives other than permissible. Sales in January, 1931, were smaller than in January, last year, the decreases being 14 per cent for black blasting powder, 19 per cent for permissibles, and 17 percent for high explosives other than permissible. Sales in January 1931 when compared with soles in December 1930, show increases for all three classes of explosives as follows: 2 per cent for black blasting powder, 16 per cent for permissible explosives, and 7 per cent for other high explosives.

Jan 1, 1931

By Irving Hartmann, John Nagy

"The pressures produced by dust explosions are frequently so great and are developed so rapidly that widespread destruction of manufacturing equipment and buildings results. Experimental data on maximum pressures and rates of pressure rise produced in a closed vessel by numerous metal powders and by dusts used in the plastics industry were published in two previous Bureau of Mines papers.4/5/One means for reducing structural damage is provision in the enclosing walls and/or roof of rapidly opening explosion-relieving devices or relief vents through which the pressure of an incipient dust explosion can be quickly dissipated. The vents can be simply unrestricted or free openings: hinged or pivoted sash which swing outward at a predetermined internal pressure; fixed sash, with light wall anchorages; scored glass panes; light wall panels; monitors or skylights; poppet-type vent closures; paper, metal foil, or other diaphragms that burst at low pressures; pull-out diaphragms, or other similar arrangements.The use of pressure-relief vents is recommended in the dust-explosion codes of the rational Fire Protection Association,6/ and recently a special committee on explosion venting has been organized. However, technical data on which the design and distribution of relief vents can be based are meager. An experimental study on venting grain-dust and cornstarch explosions was made by the Bureau of Chemistry and Soils, United States Department of Agriculture.7/ Tests on cork fines, cinnamon, starch, barley dust, and a phenolic plastic were made in a laboratory-scale (0.1-cubic-foot) apparatus by the engineering department of the Factory Insurance Association.8/ A study on the venting of explosions of acetone-air mixtures was made by the Bureau of Mines.9/The object of the present investigation is to extend the limited knowledge on the effectiveness of pressure-relief vents of different types, shapes, and sizes. The aim is to determine the venting requirements in equipment and structures of various dimensions and shapes for dusts of widely different explosive properties. On the basis of such accumulated information, together with theoretical considerations, it is hoped that ultimately it will be possible to recommend correct venting for most operations in which a dust-explosion hazard exists."

May 1, 1946

By John S. Berber

Olefin and paraffin mixtures (C10-C16 and C10-C22) were separated from low-temperature lignite tar by urea adduction and sulfated to yield secondary alkyl sulfate detergents. The C10 ?C16 secondary alkyl sulfate showed a 99.3 percent biodegradability, and the C10-C22 fraction showed a 96.8 percent biodegradability, exceeding the required standard of 80 percent for the biodegradability of anionic detergents in washing and cleaning compounds. Chlorination of paraffins yielded a detergent of 93.2 to 93.4 percent biodegradability.

Jan 1, 1968

By W. W. Adams

[The quantity of explosives sold in the United States in January, 1931, for domestic consumption, amounted to 368,100 kegs (9,202,510 pounds) of black blasting powder, 4,810;000 pounds of permissible explosives, and 16,533,000 pounds of high explosives other than permissible. These figures are based on reports received by the United States Bureau of Mines, Department of Commerce, from nearly all manufacturing companies, and include an estimate of sues by several companies that do not furnish monthly reports. Reports actually received from manufacturers shored sales of 365,977 kegs of black blasting powder (consisting of 220,892 kegs of granular powder and 145,085 kegs of pellet powder), 4,687,900 pounds of permissible explosives, and 15,498,152 pounds of high explosives other than permissible. Sales in January, 1931, were smaller than in January last year, the decreases being 14 per cent for black blasting powder, 19 per cent for permissible, and 17 per cent for high explosives other than permissible. Sales in January 1931 when compared with soles in December 1930, show increases for all three classes of explosives as follows: 2 per cent for block blasting powder, 16 per cent for permissible explosives, and 7 per cent for other high explosives. PERMISSIBLE EXPLOSIVES: Of the 4,687,900 hounds of permissible reported sold during January, 97 per cent was used for coal-mining operations, Including 32 per cent for anthracite mines and 65 per cent for bituminous mines. The following Staten were the largest users of permissible explosives daring January: Pennsylvania, West Virginia, Illinois, Alabama, Kentucky, Indiana, and Utah. Their combined sales represented 89 per cent of the entire sales reported for this class of explosives.]

Jan 1, 1931

By L. F. Heising

The Bureau of Mines evaluated 191 composites from the central Mesabi Range, Minn., chiefly by reductive roasting and magnetic separation. After reductive roasting and magnetic separation at minus 325 mesh, 28 composites produced concentrates that contained an average of 66.0 percent iron with less than 10 percent silica. Recovery of contained iron was over 90 percent. Natural magnetic material in excess of 5 percent was present in 142 composites. Trial flotation tests were used to evaluate three samples unresponsive to reductive roasting and magnetic separation procedures, and satisfactory concentrates having low silica contents (averaging 6.6 percent) were achieved.

Jan 1, 1965

By Laurance L. Oden

Titanium-enriched smelter slag produced commercially by Quebec Iron and Titanium Corp., Sorel, Quebec, was evaluated as feed material for a process developed by the Bureau of Mines to prepare rutile. Glass-forming agents including P205, B203, and two binary mixtures were added individually to the as-received and preoxidized smelter slag, and the nonferrous tramp oxides were effectively partitioned into the resulting noncrystalline phase. Iron in the ferrous oxidation state was moderately soluble in the glass of reduced specimens but less soluble under oxidizing conditions. The solubility of iron oxide in phosphate glass exceeded the solubility of iron oxide in borate glass. Effective conversion of titanium oxide to rutile was not achieved in the high-iron commercial smelter slag, and 20 to 30 pct of the titanium remained as pseudobrookite, a mixed iron-titanium oxide.

Jan 1, 1973

By Carl F. Wingquist

In support of Bureau of Mines studies of thermal fragmentation of rock, the elastic moduli of four types of rock were measured at temperatures ranging from room temperature up to 1,500° F (1,089° K). The sonic method was employed to determine the resonant frequencies of the rock specimens and from these frequencies, the elastic moduli were calculated. Data for Young's modulus, shear modulus, and Poisson's ratio are given as a function of temperature for Dresser basalt, Reserve taconite, Jasper quartzite, and Charcoal granite. Young's modulus and the shear modulus decreased with increasing temperature up to about 1,200° F and then became relatively insensitive to temperatures from 1,200° to 1,500° F.

Jan 1, 1969

By C. Özgen Karacan

The methane emission rate into an underground mine environment from overburden strata during longwall mining is impacted by reservoir and geomechanical characteristics of the coal measure rocks in the overlying strata, as well as the presence of any coal seam. The reservoir characteristics and how they change during mining potentially affect the performance of gob gas ventholes, which consequently impacts the efficiency of methane control in the mining environment. This study presents reservoir and elastic properties of coal measure rocks in the Lower Monongahela Group in Greene County, southwestern Pennsylvania, of the Northern Appalachian Basin. Since the source of methane in this region from underground mining is located between the Sewickley coal and the Pittsburgh coal, a specific emphasis was given to this interval. Core analyses were performed in the laboratory to determine rock porosity and permeability. Geophysical logging data (gamma, density, sonic) obtained from two exploration boreholes were used for evaluating formation boundaries, shale contents, log porosities, and geomechanical properties of formations. Permeability was also calculated using density-log data and empirical equations and compared with laboratory measurements and slug tests performed in isolated intervals of boreholes. The results presented in this study can be used as data sources for reservoir studies related to the production and control of methane.

Jan 1, 2009

By Albert J. Forney

Extensive studies have been made of the various effluents found in the Synthane coal-to-gas process. Analyses have been made of the waters, gases, and trace elements present in some of the streams. Results of analyses show the water effluents are the area where extensive research is needed.

Jan 1, 1974

By E. C. Lane

This report presents the results of the Bureau of Mines' twenty-first semiannual survey of motor gasoline marketed in the United States. The 12 cities in which samples were collected have teen chosen as representative of the more important marketing territories, as it is obviously impractical to obtain a sample of every gasoline sold in the entire country. The survey reveals that the motor gasoline which is being marketed in the United States this winter is decidedly more volatile than that sold a year ago. Samples from all cities show a decided improvement in volatility except those from Laramie, Wyo., which show a small decrease in volatility.

Jan 1, 1930

By James F. Devine

This Bureau of Mines report describes tests conducted at three sites to determine if, and to what extent, a vertical presplit fracture plane placed between a blast point and detection point will reduce vibration levels. Statistical analyses indicate that the presplit fracture plane did not reduce the vibration level.

Jan 1, 1965

By L. C. IlsLey

A list of permissible mine equipment, tested and approved p or to July 1, 1934, was published in Bureau of Mines Information Circular 6813/. The present list4/ includes virtually all the electric air compressors, coal drills, mining machines, loading machines, conveyors, mine pumps, room hoists, mine telephones, rock-dusting machines, switches, electric cap lamps, flame safety lanes, electric hand and trip lamps, electric flood lamps, methane detectors, blasting units, storage-battery locomotives, tandem locomotives, mower trucks, and concrete mixers tested and approved by the Bureau to January 1, 1937. The system under which these devices were tested permits the manufacturer, after his equipment has passed certain tests prescribed by the United States Bureau of Mines, to mark his equipment with a seal showing that it has been approved by the Bureau. These tests are designed to insure that equipments have the minimum requirements for safety in use. The only object of the bureau in making such tests and publishing lists of permissible equipment is to help decrease the hazards of mining.

Jan 1, 1937

By Larry L. Anderson

Enormous quantities of organic wastes are produced each year in the United States. The total amount is in excess of 2 billion tons and at least 880 million tons of this is moisture- and ash-free organic material (dry organic solids), representing a potential energy source of significant magnitude that is not being utilized. Bureau of Mines scientists have developed methods for converting these wastes to convenient energy forms. This report itemizes and evaluates for the first time in detail the quantities and sources of moisture- and ash-free organic material contained in manure, urban refuse, industrial wastes, sewage solids, and agricultural wastes in the United States. Furthermore, estimates are presented for amounts of organic wastes collected or concentrated. The potential for fuel, either oil or gas, from both the total organic wastes generated and those collected or concentrated is also estimated.

Jan 1, 1972

By Albert L. Toenges, Henry E. Dekay, James N. Scudder

Support of the immediate roof in coal mines is essential for their safe operation, and timbers are the most common means of support. Their effectiveness depends upon their resistance to decay. The theory has been advanced by some mine operators that rock dust, which is applied to ccal-mine workings to prevent propagation of explosions, accelerates the decay of mine timbers. As the results of part 1 of this study were inconclusive, the study was continued. Its principal objectives are: 1. To determine the effect of rock dusting upon decay of mine timber. 2. To compare the extent of decay of timbers in two mines in which underground conditions are similar. 3. To determine the loss in strength of the timbers after exposure to mine atmosphere. The studies were carried on in the Crucible mine of the Crucible Fuel Co. where the first part of this study was made, and in the Isabella mine of the Weirton Coal Co. The mines are on the Monongehela River and are adjacent.

May 1, 1943

By J. W. Town

Recrystallization studies on chrome-bearing spinel materials were made by the Bureau of Mines to determine the effects of certain fluxing agents and cooling rates on the chromium-to-iron ratio of recrystallized spinel. Statistically designed and evaluated tests showed that the ratio of chromium to iron in naturally occurring chrome spinel could be increased from 1.5 to 1 to over 7 to 1 and that the ratio of chromium to iron in the chrome-spinel in a stain-less steel slag could be raised to over 18 to 1. Silica, magnesia, and lime had significant positive effects, while alumina had a significant negative effect. Cooling rates of 200 C per hour in a programmed spiral globar electric furnace were satisfactory for growing crystals of recoverable size.

Jan 1, 1967

By G. L. Oldright, Virgil Miller

"This paper is the eighth; of a series on smelting in the lead blast furnace, and the third' of a group on the modifications brought about by the introduction of rich charges.ACKN0WLEDGMENTSThe data that appear in these articles were obtained through the courtesy of the operators of the Bunker Hill smelter at Kellogg, Idaho. The authors take this opportunity to express their appreciation to Stanley A. Easton, the vice-president and general manager, Frank M. Smith, smelter director, and to A. F. Beasley, the smelter superintendent, and his staff.INTR0DUCTI0NIt has been noted that the gases issuing from the top6 of the charges in the International Smelting Co.'s furnaces at Tooele, Utah, were very similar in composition to the gases from the top of the iron blast furnace, as they contained about 26 per cent of CO and 12 per cent of C02, the rest of the constituents being mainly nitrogen with a very little hydrogen and oxygen. It has been seen that where the column of coke was sufficiently high, the production of C0 gas to carry out the reduction of lead ores was accomplished in about the same manner as in a gas producer. In some cases, there was a little oxygen in the ""top gas"" -- usually not over a few tenths of a per cent, but at times amounting to several per cent. The presence of this gas was attributed to irregularities in operation that permitted air to come up through the tuybres to the surface without meeting any coke that was incandescent. Only a hundredth of a per cent or so of sulphurous oxides was present in the gases issuing from the top of the furnace."

Apr 1, 1931

By J. D. Davis

On May 15, 1936, Congress authorized the Bureau of Mines to conduct certain studies, experiments, and. investigations of subbituminous coal and lignite.4/ Appropriations were made in July 19 7, and since that date an active investigation has been underway to complete the provisions of the act. Part of the investigation has included a comprehensive survey of the known properties of the lower-rank non-coking coals, and provisions were made to obtain more data on certain varieties. In line with this plan, a typical subbituminous coal was selected for an extended series of tests in the standard. Bureau of Mines-American Gas Association unit,5/ at the Central Experiment Station. This particular noncoking coal was the first one of its rank that had been tested in the apparatus; for this reason the results are of particular interest because the testing apparatus was originally designed for use in studying the coke- and gas-making properties of coking coals. The test as described below has been developed by the Bureau of Mines since 1927 through a cooperative agreement with the American Gas Association.6/ Ninety to 180 pounds of coal is heated in a circular retort, 13 to 18 inches in diameter, at wall temperatures ranging from 500°C. to 1,110°C. in 100°C. steps. All products are collected and measured; their physical and chemical properties are then carefully determined to ascertain the gas- and coke-making properties of the coal. During the last 10 years approximately 50 representative American coals have been tested in the Bureau of Mines equipment. The results on the first 30 coals and a complete description of the test procedure are contained in a joint publication of the Bureau of Mines and the American Gas Association.7/ The remaining twenty coals have been reported in Bureau of Mines reports as Technical Papers and Bulletins.

Jan 1, 1939

By J. J. Sammarco

Light emitting diodes (LEDs) are emerging as viable replacements for incandescent-based cap lamps used in mining. The photometric and energy characteristics of these light sources differ in important ways. The present paper describes the performance of LED and incandescent sources in cap lamps in terms of correlated color temperature, color rendering, light output, electric power, ambient temperature and airflow, and light source aging. Importantly, these characteristics can influence a miner?s ability to spot mining hazards thus impacting safety. Secondly, some of these characteristics interact with the operating life of the cap lamp?s battery power, such that differences between LED and incandescent sources can be magnified toward the end of a 10­hour battery discharge cycle. Empirically, we have determined that after 8 hours at an ambient temperature of 25 °C, the average light output of an incandescent cap lamp can decrease to about 69% of its initial value when powered by a lead-acid battery and it can decrease to about 65% of its initial value when powered by a nickel-hydride battery. An LED-based cap lamp using a constant current drive circuit can maintain about 96% of its initial value when powered by a nickel-hydride battery. Real-world tests addressing the effects of ambient temperature and airflow on the light output of an LED and incandescent cap lamp were conducted in the NIOSH Safety Research Coal Mine (SRCM). The LED cap lamp yielded a vertical average illuminance improvement of approximately 9.5% and the INC cap lamp yielded a vertical average illuminance degradation o f approximately 4%. The differences between LED and incandescent cap lamps were further quantified by the calculation of ?mesopic luminance? data that indicated for the same photopic luminance (i.e., as measured using a conventional light meter) the LED cap lamp could be up to 38 % more efficient than the incandescent cap lamp with a lead-acid battery at the end of the 10-hour driving cycle. Lastly, accelerated life tests were used to empirically determine light output depreciation as the incandescent light source age approached its useful life. There was about a 35% decrease in light output. This is quite considerable, especially given that the light output will decrease an additional 30% to 45% over the period of a 10-hour shift. The implications of the differences between LED and incandescent sources are discussed. This information is crucial in determining how visual performance could be affected for real-world conditions where batteries discharge during the work shift and as the light source ages. To date, only idealized conditions have been used for LED and incandescent cap lamp visual performance research.

Jan 1, 2008