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By J. K. Richmond

Early research on coal dust explosions by the Federal Bureau of Mines and in other countries is reviewed to examine the effect of a single inhibitor, rock dust, on the explosion limits of coal dust. The parameters studied in this research included coal dust fineness, volatile content, and type of initiation. This research resulted in appropriate safety regulations in the respective countries. Also reported are the results of recent research in the Experimental Mine of the Bureau of Mines to investigate in detail the limits of coal dust explosions; the research used three types of coal with rock dust added as the independent variable. New experimental techniques and new criteria for defining propagation/nonpropagation were applied to the experiments. Also, a limit explosion propagation model is proposed based on the assumption of rapid devolatilization of the coal particles, with the subsequent combustion of the evolved volatile products contributing primarily to the propagation of the explosions. The model assumes also that the resultant char acts mainly as an inert diluent similar to the rock dust. The model also suggests that the function of stronger initiation is mostly to lift more dust from the mine surfaces.

Jan 1, 1975

By G. St John Perrott

"The United States Bureau of Mines is cooperating with the State of Utah and the City of Salt Lake in an investigation of methods of abating the smoke nuisance in Salt Lake City. In the course of this work samples of the atmosphere have been collected and analyzed in an attempt to determine the part played by sulphur dioxide or smelter gases in polluting the air at Salt Lake City.A fairly wide-spread opinion exists in Salt Lake City that the smelters contribute appreciably to the smoke nuisance. The gases discharged from the smelter stacks are believed (1) to float over the city in a heavy blanket which prevents the smoke from rising, and (2) to unite with the water vapor in the air to form corrosive fogs injurious to health and property.The first of these theories seems untenable. If the gas did not mix with air it would sink, owing to its heavier specific gravity, and form a blanket an the earth. Actually, the gas diffuses rapidly in air and any part reaching Salt Take must he thoroughly diluted. Perhaps sulphur dioxide in sufficient concentration might aid in fog formation. The more obvious nuisance, however, would be the injury to health and vegetation.The Garfield smelter is 16 miles west of the city, The Murray smelter 8 miles south, and the Midvale smelter 12 miles south. Under normal operating conditions, a relatively small amount of solid matter is discharged from these stacks. The toxic gaseous constituent of the discharge is sulphur dioxide, it is being discharged from the smelters the year round. If they are a factor in the city's smoke problem, the concentration of this gas in the air of the city should be appreciable and should increase toward the smelters, the con centration being highest with a south or a west wind."

May 1, 1920

By L. E. Geyer, W. W. Adams, M. G. Parry

"More than 73 million pounds of rock dust were used by the bituminous-coal-mining companies in the United States during 1930 to present or limit loss of life and destruction of property from explosions of gas and coal dust in underground mining operations, according to statistics compiled by the United States Bureau of Mines from reports furnished by mine operators. The mines using rock dust produced 65. 691, 753 tons of coal during the year, more than 30 percent of the total production of bituminous coal from underground mines in the United States that year. Although only 382 out of a total of 5,629 active underground bituminous mines applied rock dust to underground working as a precaution against explosions, they were chiefly the larger producing mines, employing 25.4 percent of all of the underground bitumious mine workers in the United States and accounting for 27.4 percent of the total number of man-hours worked underground at bituminous mines.a summary of the reports for the 382 mines using rock dust showed a total production of 96,691,755 tons of bituminous coal, 89,503 men employed underground, and 129,718,965 man-hours worked by the underground employees. (See tables 1 and 2.) These mines averaged 8.76 pounds of rock dust per ton of coal shown by reports from 385 mines using rock dust in 1932 (See table 3.)"

Nov 1, 1935

By K. K. Kershner

The purpose of this investigation was to develop methods on a laboratory scale for recovering tin from metallurgical slime, Tin chlorides were volatilized using mixtures of hydrogen chloride and reducing gases, such as hydrogen, carbon monoxide, hydrogen sulfide, ethane, propane, and butane. Optimum conditions were found to be n mixture of 3:1 of hydrogen and hydrogen chloride at 475° C. Over 95 percent of the tin was volatilized as chlorides. Low temperatures and relatively rapid rates of reaction are distinct advantages of the chloride volatilization process. Research is being continued with various slimes and will be extended to tin ores, where the method offers interesting economic possibilities in comparison with current tin-smelting practice.

Jan 1, 1957

By George E. Blandford

A deterministic model to assess the hydrologic impact of small watersheds subjected to unsteady storm events is presented. The overland flow model is based on the kinematic wave approximation coupled with a Green-Ampt infiltration equation. The Green-Ampt infiltration parameters are estimated using the USDA-ARS parameter estimation technique which is based on soil moisture-tension data. A Galerkin finite element formulation of the kinematic wave approximation is presented for the deterministic analysis of overland flow on small watersheds. The finite element formulation includes linear, quadratic and cubic Lagrangian one-dimensional spatial elements. A linear time variation is assumed which includes both explicit and implicit time marching algorithms, depending on the choice of the time weighting parameter. The implicit time algorithms result in a system of nonlinear equations which are evaluated using a modified Newton-Raphson iteration scheme. Initial solution estimates are generated using a linear finite difference procedure. The coupled infiltration overland flow model is tested using storm data for impervious surfaces, a laboratory soil flume, and two natural, USDA-ARS experimental watersheds.

Jan 1, 1983

By M. J. Reasor, J. M. Antonini, L. Wu, K. Van Dyke, Z. Ye

The inhalation of silica has been shown to produce a dramatic inflammatory and toxic response within the lungs of humans and· laboratory animals. Currently, no effective treatment exists for workers who may have been exposed to the inhalation of silica. The objective of this study was to develop an animal model in which we could evaluate the effect that anti-inflammatory steroids have on the acute silica-induced pulmonary inflammatory response. Male Fischer 344 rats were pretreated with either dexamethasone (2 mg/kg) or saline vehicle (i.p.) on days 1, 3, and 5. On day 6, the animals from the two groups were then intratracheally instilled with either silica (20 mg/0.5 ml saline vehicle) or saline vehicle (0.5 ml). Twenty-four hours after the instillations in the non-steroid group, significant increases occurred in total protein, total number of cells, neutrophils, and lymphocytes recovered from the lungs of animals treated with silica compared to saline controls. Silica also caused dramatic increases in the luminol-dependent chemiluminescence (LDCL) of lung tissue and bronchoalveolar lavage (BAL) cells. The LDCL reaction was markedly decreased by either superoxide dismutase (SOD) or N-nitro-L-arginine methyl ester hydrochloride (L-NAME). SOD is involved in the enzymatic breakdown of superoxide anion, while L-NAME, a nitric oxide (NO) synthase inhibitor, prevents the formation of NO. When the superoxide anion and NO react, they form the highly oxidizing substance peroxynitrite. This study then implicates peroxynitrite as an agent which may be involved in the silica-induced oxidant lung injury. When the animals were pretreated with the steroid dexamethasone, there was a complete protection against the biochemical, cellular, and chemiluminescent indices of damage caused by silica. The mechanism in which the steroid protects the lung from damage may be due to the ability of dexamethasone to block the induction of NO synthase. With further study in animals, the anti-inflammatory steroids may be useful in the treatment of silicainduced lung injury.

Dec 1, 1995

By H. H. Schrenk, Carlton E. Brown

"INTRODUCTION The angle at which a hole is drilled has long been thought to affect the amount of dust disseminated into the air during wet drilling. The amount disseminated has been reported as increasing rapidly with the approach of the angle of the hole to the vertical (up) position. 4/ This has been explained commonly as being caused by a decrease in contact of water with the face of the drill hole; increase in amount of sludge dropping through the air; and increase in amount of sludge running down the drill steel and being thrown into the air by the rotation of the drill steel and by leakage of air from the front head of the drill.The steep up angles of the holes drilled are responsible, at least partly, for the higher dust concentrations found in such places as raises, compared with those at level faces, where most of the holes are drilled at angles farther from the vertical (up) position. The mining industry is coming to realize more and more the importance of the angle of the drill hole as a contributing cause of the high dust concentrations found in some raises. Much work is being done to counteract the effect of the angle of the drill hole on dust dissemination. The rate of rater flow through drill steels is being increased by the use of water tubes of larger diameter or by higher water pressures to obtain better contact between water and the face of the drill hole. Traps are being developed to catch the sludge from the drill hole and allow it to drain down through a special pipe before it drops through the air or runs down the drill steel. Drills that permit little or no air to leak from the front head along the drill steel are being designed and used. Care is being taken to prevent the exhaust from the drill dispersing the sludge into the air."

Feb 1, 1938

By N. N. Moebs

The atmosphere in part of an air-sealed coal mine was monitored continuously through a drill hole for oxygen content to determine the effectiveness of sealing a mine against the entrance of air and the major force that caused the phenomenon of mine breathing through the overburden. The differential pressure across the seal and the barometric pressure on the outside also were recorded. A general correlation, obtained between the oxygen level, differential pressure, and barometric pressure, indicates that changes in air pressure are the cause for periodic replenishment of the oxygen in the mine. Mine effluent quality was determined by conditions in many sections of the mine and could not be related to the oxygen level at the drill hole.

Jan 1, 1972

By S. E. Khalafalla

The Bureau of Mines investigated variations in the activation energy for the carbon monoxide reduction of magnetite and ferrous oxide with respect to the state of aggregation of the oxide material. Reduction phenomena can only be satisfactorily explained by including an adsorption step in the reduction process. Summation of the values of the exothermic heat of chemisorption and the variable apparent activation energy for reduction yields a nearly constant value of about 50 kcal for either ferrous oxide or magnetite regardless of whether they are aggregated in pelletized form or coarsely crystalline particles.

Jan 1, 1965

By Edward L. McHugh, Charles Sabine, Louis J. Denes, Jami M. Girard, Peter Metes

The Spokane Research Laboratory, National Institute for Occupational Safety and Health, is investigating various remote sensing technologies as possible tools to detect, monitor, and mitigate hazardous situations in surface mines that could lead to catastrophic slope failure. Promising technologies include a field-portable spectro-polarimetric imager and a stationary interferometric radar device. Field tests were conducted of a prototype visible and near-infrared spectro-polarimetric imager (SPI) built at the Carnegie Mellon Research Institute. The SPI employs anacousto-optical tunable filter (AOTF) to control wavelength, a phase retarder to measure polarization signatures, and a digital camera and computer to capture data. Images obtained at the Mountain Pass and Castle Mountain mines in southeastern California showed that the instrument is capable of obtaining hyperspectral images of highwalls, outcrops, hand samples and drill core in the field. We have retrieved spectra from Mountain Pass images that closely match those of bastnaesite and have had some success in classifying images. Although radio frequency noise in the data limited spectral classification of imagery, we project that careful alignment of the AOTF should minimize the noise and greatly improve classification.

1. In 2001, a total of 281 metal mining operations reported employment to the Mine Safety and Health Administration (MSHA) (down from 309 metal mines in 2000). Metal mines were the smallest mining sector, 1 comprising 1.9% of all mining operations. This was the lowest percentage of all mining sectors. • The median number of operator employees per metal mine was 17.5.2 • Gold mines comprised 43.1% (n = 121) of all metal mining operations. Other types of metal mines were copper ore (n = 37, 13.2%), iron ore (n = 27, 9.6%), and lead and/or zinc ore (n = 24, 8.5%). • Nearly 20% (n = 55) of metal mines were located in Nevada.

Jul 1, 2003

By Robert Howard

With the rapid depletion of the Peerless Coal Co.'s mine in Spring Canyon, it was necessary, if the company was to remain in the coal-producing business, to look to the development of a new property or to acquire a mine already developed. After careful investigation of several operating properties it was decided by the officials of the company to take over the lease on an undeveloped acreage held by a private party in Price Canyon, about 3 miles north of Castle Gate, Utah.

Jan 1, 1930

By G. A. Apell

The presence of considerable mineralization at the surface together with other favorable conditions suggested inclusion of the Nigger Jim diggings area in a comprehensive study of shallow lead deposits in southwestern Wisconsin. The area, which was the site of considerable shallow development some 60 to 70 years ago, offered the possibility of substantial quantities of lead at near-surface horizons. The investigation included completion of 30 churn-drill holes totaling 1,808 feet of drilling, 2 diamond-drill holes totaling 164.5 feet of drilling, and 25 feet of test pitting in two excavations. The degree of mineralization was determined in an area l,500 feet long and 150 to 300 feet wide along a mineralized trend that has not been investigated beyond the limits of the zone drilled by the Bureau of Mines.

Jan 1, 1948

By J. J. Drost

This Bureau of Mines investigation studied the effect of thermal treatments upon concentratability of a western Mesabi Range nonmagnetic taconite ore and is a sequel to Bureau of Mines RI 7567. Magnetic tube tests were used to develop the data needed to calculate separation efficiency, the primary measure of concentratability. A horizontal tube furnace was employed to heat treat and reduce the hematitic ore samples. The two variables studied were roasting temperature and cooling method. The manner of cooling, either by slow cooling or quenching in water, produced no significant difference in concentratability. Roasting temperatures employed ranged from 500° to 1,000° C, and a temperature of 650° C effected the best concentratability. The temperature of 650° C correlated with the most effective roasting temperature for grindability.

Jan 1, 1973

By M. B. Cooke, A. D. Bauer, E. W. Dean

The Bureau of Mines is collecting and analyzing representative samples of crude petroleum from all the producing fields in the United States , and the results are being published in a series of reports that are preliminary to the issue of a bulletin covering the entire survey . The bureau has recently completed a survey of crude oils from the Kansas district . In all 27 samples were collected and analyzed , under the direction of A. W. Ambrose , chief petroleum technologist of the Bureau. Valuable assistance was received through the cooperation of oil companies operating in the State , especially the Prairie Pipe Line Co. , and the Empire Pipe Line Co. The present report issued as Serial 2322 , on the Kansas crudes , forms the fifth of the series . Of the four previous papers , the first ( No. 2202 ) deals with crudes from the Eastern fields of the United States , the second ( No. 2235 ) with crudes from the Rocky Mountain district , the third ( No. 2290) gives additional data , cn viscosities and pour tests , for the crudes from these two fields , and the fourth ( No. 2293 ) covers the fields of northern Texas , northern Louisiana , and Arkansas . The details of the methods of collecting samples , making laboratory tests and interpreting results , have been discussed in these earlier reports . It has also been pointed out that the only adequate method of interpreting analyses of crude oils is to compare the individual reports with the analysis of some crude oil that is familiar to the operator . For this reason , no comprehensive discussion of the results of the Kansas survey is attempted, although some general statements may be made .

Feb 1, 1922

By Bruce Cantrell, K. L. Rubow

"INTRODOCTIONMeasurement of the contribution of diesel exhaust to respirable aerosol in mine environments has become increasingly important because of current concerns over the occupational health effects resulting from exposure to diesel emissions. In response to this, the U.S. Bureau of Mines is developing and evaluating new sampling methods for measuring diesel aerosol in underground mines. Two such techniques are being studied by the Bureau, size selective sampling and Chemical Mass Balance (CMB) modeling. These techniques use measurable physical or chemical characteristics of a mine aerosol sample to infer the amount of diesel particulate material contained in the sample.Size selective sampling is being adapted for measurement of diesel aerosol by the Particle Technology Laboratory (PTL) of the University of Minnesota under sponsorship by the Bureau. 1 It is based on the premise that diesel and mineral dust aerosol can be physically separated by size and collected during sampling using inertial impaction. An independent effort by the National Institute for Occupational Safety and Health to develop a size selective sampling technique was also sponsored by the Bureau.The second technique, CMB modeling, is being developed by the Bureau as an alternative measurement technique to referee the results obtained using size selective sampling.3 It compares measured trace element ""finger prints"" of aerosol sources with similar profiles of mine aerosol samples. From these, the portions of the sample contributed by each source can be determined. Results of these investigations in underground coal mines have confirmed that diesel and coal dust aerosol are of different size and can be measured separately using size selective sampling techniques.A major difference in diesel usage among underground mines is the requirement for exhaust gas cooling systems in coal and gassy noncoal mines. Nongassy mines usually employ limited exhaust conditioning in the form of catalytic converters, which have limited effect on primary exhaust particulate. The cooling system in most general use in gassy mines is the water scrubber. This device has little effect on most of the gases but removes particulate material from the exhaust. 5 Because of this, exhaust aerosol characteristics in nongassy mines are expected to be different. To see if size selective sampling techniques can be used in such mines, the Bureau and the University of Minnesota conducted a second study in three metal and nonmetal mines, two nongassy and one rated as gassy."

Jan 1, 1990

By Steven R. Davis

Dear Interested Party: Subject: Notice of Intent to Solicit Outside Opinions Regarding Amendments to the Rules Concerning the Leasing of State Owned Lands for the Mining of Metallic Minerals The Department of Natural Resources, Division of Minerals, is seeking outside opinions concerning the leasing of state owned lands far the mining of metallic minerals. Enclosed for your information in a copy of the Notice of Intent to Solicit Outside Opinions Regarding Amendments to the Rules Concerning the Leasing of State Owned Lands for the Mining of Metallic Minerals.

Jan 1, 1994

By Maria I. De Rosa

The U.S. Bureau of Mines conducted experiments for predicting materials' ease of combustion (smoldering onset, smoldering, flaming, and decomposition rates) by means of submicrometer smoke particle characteristics for the development of a simple test method. The experiments were carried out in an approximately 20-L furnace, with a 10-L/min airflow through the furnace for a 14-min duration, at set furnace temperatures of 150°, 250°, and 1,000° C. The variables studied as a function of time were the onset time of smoke particles, time and duration of maximum smoke particle generation, average concentration of smoke particles, and particles' average diameter, mass weight loss, and furnace temperatures. Results show that the onset time of smoke particles is predictive of materials' ease of smoldering, and the time of maximum smoke particle generation and its duration, coupled with mass weight loss, are predictive of materials' ease of smoldering and flaming (depending on the experimental temperatures), and decomposition rates.

Jan 1, 2010

By A. D. Hahn

This report describes reconnaissance by the Bureau of Mines of titanium-bearing beach sands on Ship Island in the Gulf of Mexico off the south coast of Harrison County, Miss. The purpose was to determine the ilmenite, rutile, and associated heavy-mineral content of black-sand-bearing beach sands. The investigation was part of a survey of titanium resources of the United States. Ilmenite (FeTi03), an iron-titanium oxide, is the major titanium-bearing mineral consumed in the titanium pigment industry. Rutile (TiO2), titanium dioxide, is used mainly as a constituent in welding-rod coatings and in producing titanium metal. The major fieldwork was conducted during the first half of February 1961. Nine holes, totaling 220 feet of bore, from which 110 samples Her taken, were drilled at widely spaced intervals on the island.

Jan 1, 1962

By W. E. Wallace

Volume-rate-of-flow measurements were made of the flow of mercury through porous samples under conditions of no field, magnetic field transverse to the direction of flow, and transverse magnetic field and electric current to determine if a magnetic method might be potentially useful in the study of pore-size distribution. No change was observed in the flow rate from the application of a magnetic field alone. The application of both field and current produced an electromagnetic pumping action with or against the direction of flow, depending upon the direction of the electric current. This pumping effect was observed to be greater in a rectangular porcelain sample than the calculated value for an equal-Sized open channel.

Jan 1, 1969