Search Documents

By Lorenz E. Sieffert, Lawrence B. Berger, H. H. Sehrenk, Ralph W. Stewar, James A. Gale

"INTRODUCTION The purpose of the investigation discussed in this article was to evaluate the toxic hazard from gases produced when thermosetting plastic materials used for electrical insulating purposes are burned or thermally decomposed in enclosed spaces. For brevity the term ""toxicity"" is used throughout the article to refer to the nature of gases produced under these conditions. A need for immediate study of the problem was created as a re¬sult of the battle damage reports received from various United States Fleet units. These indicated that the fumes emitted when these materials were burned or thermally decomposed had, in several instances, resulted in toxic atmospheres. In attempting to develop a suitable test method for evaluating toxicity, it was recognized that no single test procedure could be expected to duplicate the variety of conditions that might exist in an actual fire aboard ship. In view of the immediate need, however, it was felt that considerable information could be obtained, at least to classify comparatively the several types of materials as to the toxic effect caused by burning or thermal decomposition, through the development of a sound empirical method which could be applied to all of the materials. On this basis, it was decided to modify the Navy flame resistance test for thermosetting plastics to render it applicable to the determination of the toxic, gases evolved when this test was employed. A wide variety of materials was tested, both molded and laminated, to cover the types commonly used by the Navy in electrical applications. Toxicity determinations were conducted at the Bureau of Mines Central Experiment Station, Pittsburgh, Pa. Parallel tests, to determine the flame resistance of the materials, were conducted at the Material Laboratory, U. S. Navy Yard, New York, N. Y."

Oct 1, 1947

By Marting J. Gavin

The twentieth century has often been spoken of as the age of petroleum, and from many viewpoints it can be justly considered so. Certainly the petroleum industry is one of enormous importance to this country, industrially, financially, and economically. The United States, however, at present producing over 60 per cent of the world's total output of petroleum, is not producing petroleum at a sufficient rate to provide for its own domestic, consumption. For several years this country has been importing increasing quantities of crude and partly refined oils from Mexico, and has been drawing heavily on domestic stocks of petroleum. Production in the United States is increasing, but it is not increasing at the same average rate as domestic consumption, nor is it probable that in the future domestic production will increase sufficiently to satisfy the demands of domestic consumption, but on the contrary, in the opinion of those best qualified to know, the peak in the curve of domestic production of crude petroleum will be reached in a comparatively few years, whereas the consumption of petroleum and its product will increase at a continually growing rate. This country, then, must turn, and as the increasing imports from Mexico indicate, is turning to other sources than the crude petroleum, produced in this country to make up the deficit between domestic production and domestic consumption of petroleum and its products,

Jun 1, 1920

By D. Harrington

"While distribution of air currents to working faces is a necessity in coal mines, especially those having explosive gas, advancing faces in metal mines rarely have circulating air other than the ordinarily inadequate amount supplied through the compressed air system. Even where comparatively large quantities of air pass through main mine shafts and levels. whether the circulation is actuated by fans or by natural ventilation, only occasionally can a metal mine be found where any considerable percentage of the ""blind ends"" has circulating air of sufficient velocity to be measured by an anemometer or even be discerned by deflection of flame of candle, or of acetylene lamp; and unfortunately these ""blind ends"" include nearly all of the places from which rock is taken.During several years study of metal-mine ventilation in various mining districts of the United States, it has been found that in some mines many of the workers in ""blind ends"" practically continually breathe air with 0.02 to 0.04 per cent of CO gas from unremoved fumes from explosives; in other mines CO2 chiefly from timber decay and breathing of men, is so high that a candle will not burn though usually the acetylene lamp will, hence oxygen is below 17 per cent but above 12 per cent; in some regions CO2 from strata fills the entire mine forcing cessation of work; in other mines in dead ends, gases such as nitrogen, H2S, SO2, etc., are found under some conditions. In many regions with hot rock or water (especially in deep workings) men in blind ends must work with little or no circulation, in air above SO degrees F. and even above 90 degrees, relative humidity only too frequently being around 100 per cent; in other regions workers in blind ends in practically ""dead"" air must continually breathe enormous quantities of finely divided rock dusts. All of the above conditions are decidedly harmful to health and prevent the worker from delivering anything approaching an adequate quantity of work, and in addition, some of these conditions have direct or indirect effect in bringing about definite increase of accidents; all of the above mentioned bad conditions in ""blind ends"" in metal mines as well as their ill effects, are remediable by providing at those places adequate quantities of fresh circulating air."

Nov 1, 1923

By Launa Mallett, Charles Vaught, Michael J. Bmick

Since 1991 the Pittsburgh Research Center (PRC formerly part of the U. S. Bureau of Mines) has been tapping u valuable resource-researchers have recorded extensive interviews will, 30 individuals who are recognized as experts in the area of mine emergency response. These veterans related stories and observations from events experienced during as many as 47 years of response activities. Overall, the response veterans averaged 29 years of mine emergency response experience and 35 years mining experience. Individuals [ ] interviewed included representatives from mining companies, the UMWA and state and federal government agencies. This information was gathered so dial it could he provided to today's miners and to tomorrow's emergency response personnel. It is hoped the collective wisdom that has been obtained can be used to help train new responders and guide those decisions which mill have to be made on the scenes of future events. During interviews file emergency response experts were asked to discuss lessons they had learned through experience. The interviewers asked them to tell what they had learned that would cause them to handle similar situations differently and to tell about things they saw at past events shat the would warn others not to do in the future. In response the experts discussed a variety of things. Most of their responses, however, touched on some of the same topics including: preparedness, experience people on-site mine rescue teams, and decision making. A summary of their responses provides alt overview of [lie lessons learned on-site at tile largest mine disasters in the country.

By G. St. J. Perrott, N. A. Tolch

"The testing of explosives for permissibility for use in coal mines was begun by the technologic branch of the United States Geologic Survey in February, 1909, and continued by the United States Bureau of Mines from July, 1910; this testing has been carried on from year to year as the explosives were submitted by manufacturers. As a result of these many years of testing for permissibility a large amount of data has accumulated regarding the characteristics of permissible explosives. The manufacturer expects a sample of explosive submitted for test to meet the requirements for permissibility, otherwise the sample would not be submitted. However, in spite of the careful regulation and preparation of the formulas a certain percentage of explosives fails to pass the gallery tests. It is therefore interesting to note the proportion of failures at the gallery for a given composition of explosive. The fact should be emphasized that this discussion deals with all explosives submitted for test, both those which passed the tests and those which failed to pass. Explosives that failed to pass the tests were never designated as permissible explosives and have never appeared on any list of explosives permissible for use in coal mines.The Bureau of Mines classifies permissible explosives in two ways, according to the quantity of poisonous gases produced and according to the characteristic ingredient of the explosive.4 In this paper only two types of the latter classification are considered, as follows:"

Dec 1, 1929

By C. P. Mangelsdorf

When the finely bedded shale frequently encountered over coal seams experiences a separation, the material below the separation must behave like a beam or plate in that it must resist both bending and shear. Be-cause of the weakness in interlaminar shear inherent in such strata, shear deflections that are usually ignored in isotropic beam theory may account for a significant part of the total roof sag. Similarly, when a roof truss is installed in such a roof the upward displacement reducing the sag will have components due to shear as well as bending. Questions asked by mine operators about the installation of roof trusses frequently deal with optimum position, slope, and initial tension of the inclined chords. This Bureau of Mines report examines the effects of those chord parameters on the strain energy of both shear and bending and offers optimum values that will minimize the total strain energy of the immediate roof. Design charts are provided, several design examples are included, and the results are compared with current practice. The effects of in situ stresses are investigated and are shown to be equivalent to an additional load on the beam.

Jan 1, 1988

By J. E. Murphy

Purification of samarium metal by sublimation and by vaporization from a low-melting metal flux, at the same temperature, were compared. Vaporization proved more effective for removing impurities such as magnesium, calcium, and manganese. Recovery of samarium, however, is more rapid by sublimation because of its constant rate of distillation.

Jan 1, 1970

By Wilbert T. Malenka

In its search for a highly productive mining system for anthracite beds pitching from 100 to 200, where conventional mobile equipment cannot be used) the Bureau initiated a longwall project by introducing a shearer drum cutter loader of European origin. Because of the undulating nature of the roof and floor and changing bed thicknesses, the machine proved inflexible and extra work was required in lifting bottom coal and blasting top coal.

Jan 1, 1966

By L. A. Neumeier

Sound experimental ingots of zinc alloys for use as rolling slabs were cast with a specially constructed, semicontinuous casting machine. Nominal alloy compositions of Zn-1.0 percent Cu, Zn-0.12 and 0.36 percent Ti, and Zn-1.0 percent Cu-0.03 to 0.36 percent Ti were cast. This Bureau of Mines study was conducted to evaluate the suitability of the casting procedure for providing stock for rolling into sheet. Microscopic examination of ingot sections revealed structures in which grain size varied from the outer to center ingot zones. Columnar grains present in the center zone of the Zn-1.0 percent Cu ingot were absent in the titanium-containing ingots. The ingots with titanium displayed a finer grain size and eutectic structure in the center ingot zone than in the outer zone; the transition in grain size between the two zones was quite abrupt in some ingots. The overall grain size of the titanium-containing ingots was finer than that of alloys cast by more conventional methods. Chemical analysis revealed that compositional segregation is not a significant factor in the formation of the ingot structure. Microstructural studies of small ingots of similar alloys solidified at slow, fast, and intermediate rates confirmed that the ingot structure in the semicontinuous-cast ingots is related to cooling rate, which is, in turn, related to the particular casting machine design and the influx of cooling water on the withdrawing ingots. Microstructures of thin sheet hot-rolled from slabs of the semicontinuous-cast ingots demonstrated that the ingot structure does not preclude the rolling of sheet having a uniform microstructure. Results of hardness surveys of the semicontinuous-cast ingots demonstrated that copper and titanium exert essentially additive hardening effects in these cast alloys.

Jan 1, 1968

By Robert J. Hundhausen

This information circular is one of a series of Bureau of Mines reports dealing with mining and milling methods and costs . It describes the operations at the Little Pittsburg mine in the Pine Creek area of the Coeur d'Alene mining region near Kellogg , Idaho . The mine and mill have been operated successfully from 1942 to the present .

Feb 1, 1948

By Frank E. Cash, John A. Johnson

"INTRODUCTION During the 6-year period, 1940-45, 481,485,000 gross tons of iron ore was shipped from the Minnesota, Michigan, and Wisconsin mines of the Lake Superior district. Approximately 367,000,000 tons, or 76 percent, of this ore was shipped from open-cut mines. The production of this large tonnage of iron ore from the open-cut mines of the Lake Superior district during the recent war was an outstanding achievement. It is questionable whether this record-breaking tonnage of iron ore, vitally needed for the successful prosecution of the war, could have been produced without the modern equipment and mining methods used in the district, The transportation of iron ore from the open-cut mines of the district is the most important phase of the mining cycle. Although some of the mines still use rail haulage advantageously, this method of haulage has been replaced at most nines with motor-truck haulage or a combination of motor-truck and belt-conveyor haulage.SCOPEThe transportation of iron ore in this report covers (1) power shovels, (2) rail haulage, (3) trucks, (4) belt conveyors, (5) shipping pockets, (6) accident statistics, and (7) safety rules pertaining to open-cut transporta¬tion. The purpose of the report is to discuss briefly and disseminate to the mining industry the modern methods, equipment, and safety practices used in transporting iron ore at the open-cut mines of the district.The 25 open-cut mines covered herein, located in the Marquette, Cuyuna, and Mesabi iron ranges of Michigan and Minnesota, shipped approximately 44,000,000 tons of iron in 1945, which amounted to 72 percent of the open-cut iron ore shipped from the Lake Superior district."

May 1, 1948

By R. L. Grayson, T. Simonyi, R. A. Andrel

"The purpose or this paper is to disclose analytical, statistical, and observational results relating to mineralogy and trace elements in respirable dust samples collected from two different mines in West Virginia. Samples were taken from longwall panels, and the panels operated in different coal seams, one located in the northern part or the state and the other in the southern region. Mining conditions and equipment arrangements on the panels will be described along with dust control techniques used. Results from sample analyses are summarized with emphasis on relationships between mineralogy, trace elements and mineral particle size to worker locations. Correlations are made between micro x-ray diffraction and energy dispersive x-ray analyses for sample mineralogy.IntroductionThrough the work of many researchers worldwide, the health of coal miners in modern societies is now protected from harmful exposure to respirable coal mine dust. A vast amount of research culminated in the exposure-response model of Jacobsen, et al, (l) which has been used to establish the 2 mg/m3 exposure limit in the United States. According to the model exposure to respirable dust for 35 years at this level or less could prevent the occurrence of a clinically significant case of coal workers' pneumoconiosis (CWP) in a miner. The exposure limit, of course, must be adjusted whenever greather than five percent free silica exists in the respirable dust.The Jacobsen model was built around a mean mass concentration exposure, which generally showed the highest correlation with both incidence and progression of CWP. As Morgan, et al noted, however, the quantity of respirable dust inhaled is not the only significant factor. 2) They noted that although mass of respirable dust correlates highe.st with the incidence of CWP, it is not a causal factor. Admittedly, the insidious processes causing the disease occur at the lund cell-dust particle level."

Mar 1, 1989

By R. V. Thurston, Edmund S. Leaver

"During the development of the sulphur dioxide leaching process for the treatment of ""mixed"" copper ores at the Southwest experiment station of the Bureau of Mines*** the pulp from treatment of roasted cupriferous pyrite with sulphur dioxide gases and water showed an unexpected amount of sulphuric acid. After following out several false premises it was found that this was due to iron in the solution, and also that this iron tended to oxidize to the ferric state if the concentration of sulphur dioxide in the roaster gases used did not rise above a certain figure. While the percentage of iron present was email it was enough to cause an entirely different set of conditions from those of the original sulphur dioxide leaching process and to promise a much wider application of the general idea. Sulphurous acid dissolves only certain copper minerals, sulphuric acid solutions certain additional minerals and ferric sulphate solutions certain further additional copper minerals, so this observation was of importance in connection with possibilities in the hydrometallurgy of the so-called ""mixed"" or partly oxidized copper ores.The work has been carried along by a number of experimenters. L. R. Eckman, junior chemist of the Southwest station, contributed largely to the early developments. L. Roberts, W. D. Bonner and C. G. Maier each in turn physical chemists at the Pacific Experiment station, (Berkeley, Calif.) have studied the reactions involved. A complete report of all the work on this process will be prepared later under the direction of O. C. Rolston. The purpose of the present paper is to place a summary of the more practical phases of this seemingly important piece of work before those interested."

Dec 1, 1923

By Boyd Guthrie

The current use of Mid - Continent crude oil for the manufacture of war products , such as aviation gasoline and lubricating cil , has caused an acute shortage of available supply from established sources . Therefore , refiners who heretofore have had no reason to use West Texas crude oils now are considering them as charging stock and need more information concerning their characteristics . The Bureau of Mines has published several reports3/ giving analyses of the most important of these crude oils . However, to make the applicable data in these publications readily available to refiners , the present compilation of analyses of West Texas crude oils has been prepared . Data showing the effect of catalytic desulfurization of naphthas from West Texas crude oils have been presented in a restricted Bureau of Mines Report of Investigations . These analyses were made under the general supervision of R. A. Cattell , chief, Petroleum and Natural Gas Division, Bureau of Mines , Washington, D. C. , and N. A. C. Smith, supervising engineer , Fetroleum Experiment Station, Bureau of Mines , Bartlesville, Okla . , and under the direct supervision of Harold M. Smith, senior petroleum chemist, Bartlesville , Okla .

Jan 1, 1944

By H. Herbert Hughes

Iceland spar is a variety of calcite ( calcium carbonate ) characterized by its purity , transparency , and perfection of crystalline structure . It takes its name from the country in which it was discovered . The actual demand for it is small , but the supplies of high - grade optical spar are so meager that the search for it has become international in its scope . Iceland spar is a scientific necessity , for without it research precision and technology would be hampered considerably . The earliest students of mineralogy were familiar with calcite , but the transparent variety was not discovered until early in the seventeenth century , when crystals of it were found in the bed of a stream in Iceland . It received little attention until 1669 , when Erasmus Bartholinus first recognized its powers of double refraction . The results of his investigation were published in a book , " Experimenta Crystalli Islandici , " which appeared in 1670. The law governing the action of the rerracted rays was discovered by Christian Huygens eight years later . The polarization of light rays in passing through Iceland spar was discovered in 1809 by Etienne Louis Malus , a French physicist , who published a paper describing the phenomenon . His work was closely followed by that of William Nicol , who in 1828 designed the Nicol prism which is still used as the source of polarized light in most optical instruments .

Jul 1, 1931

By Roy Greenfield

Estimates are given for the distance from a seismometer at which a miner can probably be detected. The procedure in making these estimates was to first establish the natural noise levels at the output of a surface seismometer for the 25 to 100 Hz frequency passband. The noise levels give the range of values which may be expected in areas with no man-made noise. For each noise level, we give the detection threshold which, when exceeded, indicates that a signal has been received. Based on the signals recorded by Westinghouse, curves are given which show the peak signal amplitude as a function of source- to-receiver distance (slant range). Curves are given for the Westinghouse seismic thumper, a 50-pound timber, and a sledge. For a given type of source, the receive signal strength depends more strongly on slant range than on any other factor. However, there is approximately a five-to-one scatter in the amplitudes. Thus, further study of factors affecting the signal amplitude might allow better estimates to be made for any particular geological setting. Combining the signal amplitude with the detection thresholds for the different noise conditions gives the distances at which a miner should be detected. These are given in Table l* below. [ ] The text also gives the increase in detection ranges which should occur if steps are taken to increase S/N by 10 dB. We feel that 10 dB is a conservative estimate of the improvement possible. During an actual rescue operation, the seismic crew and system should be capable of making on-site estimates of their detection capability, based on measurements of the site noise, and upon the best available estimates of the

Jan 1, 1974

By M. J. Dailey

This paper is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The property of the Silver King Coalition Mines Co. is situated in the western past of the Park City mining district, Utah, about 1 ½ miles southwest of the town of Park City, The elevation at the collar of the main shaft is 8,137 feet above sea-level.

Jan 1, 1930

By R. Barany

The heats of formation of anhydrous ferric sulfate and anhydrous indium sulfate were determined by solution calorimetry. At 298.15° K the heats of formation from the metal, rhombic sulfur, and oxygen were -615.6 ±O.7 kcal/mole for ferric sulfate and -649.6 ±O.6 kcal/mole for indium sulfate. Heats of decomposition at 298.15° K are given for the reaction that forms metal oxide, sulfur dioxide, and oxygen) and for the reaction that forms the metal oxide and sulfur trioxide.

Jan 1, 1965

By Gregory J. Chekan

As part of the initial investigation and validation of a new boundary-element formulation for stress modeling in coal mines, the underground stresses and displacements at two multiple-seam coal mines with unique stress problems were modeled and predicted. The new program, LAMODEL, calculates stresses and displacements at the seam level and at requested locations in the overburden or at the surface. Both linear elastic and nonlinear seam materials can be used, and surface effects, multiple seams, and multiple mining steps can be simulated. In order to most efficiently use LAMODEL for accurate stress prediction, the program is first calibrated to the site-specific geomechanics based on previously observed stress conditions at the mine. For this calibration process, a previously mined area is "stress mapped" by quantifying the observed pillar and strata behavior using a numerical rating system. Then, the site-specific mechanical properties in the model are adjusted to provide the best correlation between the predicted stresses and the observed underground stress rating. Once calibrated, the model is then used to predict future stress problems ahead of mining. At the two case study mines, the calibrated models showed good correlation with the observed stresses and also accurately predicted upcoming high stress areas for preventive action by the mines.

Jan 5, 1999

By Robert H. Schutz

This publication lists and describes devices approved jointly by the Secretary of Interior and the Secretary of Health, Education, and Welfare, under the provisions of [§]70.300-1, Part 70, Subchapter 0 of Chapter I, Title 30, Code of Federal Regulations (35 F.R. 5548, April 3, 1970), for use as respiratory protection against respirable pneumoconiosis-producing dusts. Included are type C supplied-air respirators approved under Bureau of Mines Schedule 19R and dust, fume, and mist respirators approved under Bureau of Mines Schedule 21B.

Jan 1, 1971