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By Wilbert J. Huff, Raymond H. Moore

"Black powder is employed widely in peace and war. Its properties are therefore of considerable interest to many. The Bureau of Mines frequently is asked to furnish information on its use and safe handling in the mining and mineral industries in times of peace and is now engaged in studies of its application to the arts of war.Black powder has been the agent in many accidents - some very disastrous - and its handling and use are deemed very hazardous. The belief is widespread that the hazards are due principally to the ease with which the powder is ignited by a hot spark or flame in contradistinction to high explosives; these usually are ignited only with difficulty, and some burn incompl0tely and to a certain extent are self-extinguishing. Primary precautions, .therefore, should be taken to prevent the access of heat, spark, and flame.In black powder manufacturing operations a frequent source of disaster is the initiation of fires and explosions in the wheel mills in which the sulfur, charcoal, and nitrate are incorporated. Long experience has indicated that the wheel mill probably will fire if the powder is not kept moist enough; manufacturing supervision calls for the maintenance of a minimum moisture content, at least during the milling. Accidents occur elsewhere in the manufacturing line, and in an endeavor to minimize these, particularly those happening in corning mills, one of the writers suggested many years ago that a suitable humidity be maintained in other operations in the hope that it would serve protectively as in the wheel mill. The experience of one company for many years with this practice was favorable. It seemed desirable therefore, to explore the question experimentally."

Nov 1, 1944

By John I. Kasteler

The Rambler mine is in the Douglas mining district, Albany County, Wyo. (fig. 1). The property was first operated about 1870 for gold found in the outcrop of a leached ore body. Copper and metals of the platinum group were discovered, in 1900, or soon thereafter, and intermittent mining was done until 1918, when a fire destroyed the surface plant, and the underground workings caved. The mine has since been idle. The Bureau of Mines conducted a development project on the property from October 1942 to October 1943, with a recess period between November 1942 and August 1943. Ten diamond drill holes, totaling 1,859 linear feet, were drilled on the property (fig. 2). The mine dump was sampled after preparation with a bulldozer. Assay determination and spectrographic analyses disclosed small quantities of copper and metals of the platinum group in the samples. Determinations were made on 11 samples from the diamond drill holes and 23 samples from the mine dump. The assay results and spectrographic analyses are given in tables 1 and 2. The logs of the diamond drill holes are given in an appendix to this report.

Jan 1, 1949

By T. F. Dumm, O. Trass, V. R. Koka, L. G. Austin

"The size distributions of carefully screened 2 size fractions of ground materials were determined using a Microtrac laser dif-fractometer. The size distributions were fitted to the empirical function P(x) = 1/[1 + (x50/x)1] where P(x) is cumulative mass fraction less than Microtrac size, x. The standard deviation of A for a 50 second test time was approximately 0.5, so that seventeen test times give a mean with an estimated error within t 0.25 (95% confidence level). Values of were 5.44, 4.82, 4.40 for a coal ground under different conditions, indicating statistically different shape distributions; the average value for mica was 2.91 owing to the high aspect ratio of the particles. The ratio of x50 to the geometric mean sieve size was 1.2 for the coal and 0.70 for mica.1 IntroductionKoka and Trass have presented evidence [1,2] that materials ground in the Szego mill [3] give different shapes depending on the milling conditions. The variations in shape were deduced qualitatively by viewing SEM photomicrographs of selected 1/2 screen fractions. This paper quantifies their observed differences in shape by using measurements of the size distributions of screen fractions examined in a laser diffractometer [4] (Microtrac, Model 7991). The basic concept is that particles of 'a given ""screen"" size will give a wider distribution of ""Microtrac"" size when the particles are flaky with high aspect ratios, and a narrower distribution when the particles approach the cubical and spherical geometries.2 TheoryAustin and Shah [5] have shown that coal screened within a 1. 1/2 upper-to-lower sieve size range will give rise to a much wider distribution of Microtrac size. They found that the screen interval of irregular fragments of comminuted coals or quartz gave Microtrac size distributions which could be described by the simple function"

Jan 1, 1988

By W. R. Huff

This report describes the development and operation by the Bureau of Mines of a pilot plant designed for using high-volatile A bituminous coal-in-water suspensions as a source of preheated coal and superheated steam in the pressure gasification of coal with oxygen. Figure 1 on page 2 is a block diagram of the integrated gasification process, in which a total of 70 tons of coal was fed from slurry and gasified. The present work included (1) development of equipment and methods both for mixing pulverized coal and water to produce slurry and for pumping and metering the slurry at gasification pressure; (2) development of equipment for heating the flowing slurry and, because slurry that can be pumped produces more steam than is necessary as a gasification reactant, developing equipment for removing and metering the excess steam; and (3) demonstration of the process under actual gasifier operating conditions, at a coal rate of about 800 pounds per hour and gasification pressures in the range 100 to 300 pounds per square inch gage. By using the forced-convection principle, a flow of slurry made from a caking, high-volatile A bituminous coal can be continuously heated to 600° F. in a coil-type heater. The flow rate and concentration of the slurry and the temperature gradient along the length of the heating coil must be closely controlled. In a radiant-type heater, involuntary reductions in flow rate, even momentary, can lead to coking and plugging of the heater coil.

Jan 1, 1961

By Je M. Oh

The U.S. Bureau of Mines is conducting research on the oxidation resistance and structural stability of Fe-(0-8)Cr-(0-16)Ni-(0-16)Mn-3.5Si-lAl alloys as potential substitutes for high-Cr stainless steels. Oxidation tests were conducted in air over the temperature range of 6000 to 9000 C for up to 1,000 h. Microstructures were analyzed at room temperature after hot rolling. The oxidation properties and the structural stability were found to be greatly affected by the Cr and Mn levels. Although substitution of Mn for Ni increased the oxidation rate, the Mn helped to stabilize the austenitic microstructure. Decreasing the Cr content or increasing the Mn content produced higher oxidation rates and earlier oxide spalling. In this study, reaction kinetics, oxide morphologies, and microstructure of the alloys were investigated using scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, and electron microprobe analysis.

Jan 1, 1989

By V. L. Burdick

A literature review of current uses of Mn02 in ceramic applications with suggestions for future research. Historical background, oceanographic distribution, geology, exploitation, law and politics. Uses of Mn02 in ferrites, semiconductors, catalytic processes, thermo-luminescence and photochromic materials. Select bibliography of 33 items, plus 129 references.

Jan 1, 1980

By Gary P. Sames

The Bureau of Mines recently initiated a study of geologic features that contribute to roof instability in western U.S. underground coal mines. The purpose of the study is to provide information for use in ground control planning and safety hazard reduction in that region, where mining activity has been increasing. Hazardous geologic conditions were surveyed in selected underground coal mines in Utah and Colorado, and both depositional and structural features were identified as potential ground hazards. Although the conditions found do not differ in kind from hazardous geologic conditions in the Eastern United States, they do differ in intensity of occurrence and relative importance. Three depositional features dominate where unstable roof occurs in western underground coal mines: paleochannel deposits, crevasse splay deposits, and flood basin deposits. Three structural features identified as hazardous, but not so widespread or common as the depositional hazards, are faulting, jointing, and igneous intrusions. This survey establishes a foundation for future studies aimed at reducing and preventing ground control accidents in western coal mines.

Jan 1, 1988

By Paul McIlroy

Costs of producing lead from various known resources in the United States are developed by the Bureau of Mines to define the future availability of domestic lead at various price levels. It is estimated that 60 million tons of primary lead (75 percent of the total resource) is available at $0.20 or less per pound; 72 million tons (90 percent of the total) is available at $0.50 or less per pound; and the 79 mil- lion ton total estimated resource can be obtained at a price or $1.82 or less per pound. The supply available at $0.20 per pound or less will meet demand for over 78 years at the 1970 annual consumption rate of 763,000 tons.

Jan 1, 1974

By Robert S. Warfield

The Bureau of Mines investigated a geologically favorable area in the Beluga River coalfield in south-central Alaska to determine if there were sufficient minable coal reserves for onsite utilization to meet the projected thermal power needs of the Anchorage area. A program of diamond core drilling and sampling delimited a shallow saucerlike structure estimated to contain indicated reserves of more than 20 million tons of subbitminous coal in a seam over 50 feet thick that could be mined by opencut methods. A large sample of fresh coal was taken across the full width of the seam for washability studies. This sample, with 4 volume-percent of clay partings eliminated, contained 24.4 percent moisture and 16.8 percent ash and had a calorific value of 7,162 Btu per pound. The studies indicated that mechanical cleaning would be of doubtful value.

Jan 1, 1963

By Irving Hartmann

[The explosability of coal dusts has been the subject of many investigations studies have been conducted in laboratories, in galleries and in coal faire; of several countries to obtain information on the causes, development, and prevention of mine explosions. Early laboratory experiments on it American colas dealt with pressures developed in test bomb by explosions of dust clouds and with, the effects of gas in the dust atmosphere.5/ Later, the emphasis shafted to evaluation of the relative fleet flammability and the ignition temperatures of coal dusts.6/ Much worthwhile effort was devoted to the development of Laboratory apparatus and test procedures that gave good correlation with large-scale explosion tests in the Experimental cost mine. In recent years a number of special problems were studied, mostly with bituminous Pittsburgh coal dust]

Jan 1, 1954

By R. T. C. Rasmussen

"INTRODUCTION This is the second report of investigations describing tests in full-scale commercial heats of steel-using electrolytic manganese having a purity of about 99.95 percent, produced in the Bureau's pilot plant at Boulder City, Nev. The first report dealt with tests in cooperation with two companies can the use,of electrolytic manganese in the manufacture of stainless steel. 3/ Plans aril cost estimates for reasonably large commercial, electrolytic plants based upon pilot-plant experience, as well as the comments of a number of concerns where electrolytic manganese has been tried, are contained in another publication.4/ The tests in cooperation with industry are part of the Bureau of Mines program of investigations of methods of utilizing low-grade domestic manganese ores, thereby the United States leas dependent upon foreign sources of manganese for metallurgical use. The Boulder City pilot plant already has demonstrated the feasibility of producing electrolytic manganese from several of the most important reserves of low-grade manganese ore. As the ferromanganese normally used by the steel industry represents the bulk of the Nation's manganese requirements, the usefulness and possi¬ble advantages of electrolytic manganese in the manufacture of steel must be established if electrowinning from domestic ores is to become an important factor of manganese supply.Preliminary arrangements for the cooperative tests at the Atlas Steel Casting Co., Buffalo,. N. Y., were made with E. L. Altenburg, vice president and general manager of the company, by A. A. Dow. 5/ The data on the tests at the Atlas plant presented herein are based upon reports of E. L. Altenburg and information obtained by the author during a visit to the plant to observe the initial trial heats with electrolytic manganese in the open-hearth and the electric furnace."

Nov 1, 1945

By M. A. Elliott, H. H. Schrenk, L. B. Berger, John C. Holtz

"INTRODUCTION Diesel-powered locomotives designed specifically for underground operation were used in the construction of some of the tunnels that comprise the Delaware Aqueduct in New York State. Before this there had been limited use of Diesel-powered equipment such as trucks, bulldozers, and shovels in tunnel construction in various parts of the country, but this equipment was used without modification for underground use and, in some instances, appar¬ently without due consideration of the hazards that might be created by the introduction of fuel-burning equipment into confined underground spaces.As certain definite advantages were apparent if Diesel haulage could be used in tunnel construction in some sections of the Aqueduct, the contractors who were to construct the tunnels in these sections were desirous of using, this type of haulage equipment if it could be used with safety. This matter was given careful consideration by the various agencies concerned with the establishment of safe practices on the Aqueduct project before tunnel driving was started. Of chief concern were the quantities of toxic or objectionable materials that would be discharged into the tunnel air by the exhaust of the locomotives and the volume of ventilating air that would be required to dilute these exhaust gas products to concentrations permissible in the atmosphere of working places."

Jan 1, 1947

By B. Dimitriades

The Bureau of Mines measured the reactivities of 19 hydrocarbons known to be prominently present in automotive exhaust and ambient air in a smog chamber. Results agreed well with those obtained using two other smog chambers. Reactivity scales were developed for hydrocarbons and aldehydes using the results of this work and those of a previous study. Application of the reactivity scales to automotive exhaust samples gave fair agreement between predicted and observed rate-of-N02-formation values; however, predicted and observed ozone yields were neither in agreement nor did they correlate well. This lack of correlation for ozone yield was attributed to the inappropriateness of (1) the individual component reactivity data, (2) the reactivity classification scheme used, and (3) the linear summation method. In seeking to understand this problem and to develop more appropriate reactivity scales, the data were examined from a reaction mechanism standpoint, and further studies were suggested.

Jan 1, 1975

By W. M. Mahan

This report describes work carried out by the Federal Bureau of Mines in cooperation with the General Services Administration (GSA). Tests on nickel oxide reduction were conducted at the Pyrometallurgical Laboratory at Pitts-burgh and Bruceton, Pa., and at a rented plant at Canonsburg, Pa. Nickel oxide was reduced to sponge nickel, which was then melted to produce specification-grade nickel ingots containing a minimum of 98.50 percent nickel plus cobalt and a maximum of 1.00 percent cobalt. One purpose of this study was to determine if specification-grade nickel could be made from nickel oxide produced at the United States-Government-owned plant at Nicaro, Cuba, in pilot-plant scale operations involving direct reduction and melting processes. A second and equally important purpose was to obtain cost data on the pilot-plant operation to estimate the cost of producing ingot nickel at an annual rate of 12 million pounds. Laboratory tests verified that nickel oxide, in saggers and in the presence of anthracite fines and dolomite in the ratio of approximately 20:5:1, could be converted to sponge nickel when heated to approximately 1,900° F. for about 2 to 4 hours, depending on the size and density of the oxide charge. The tests also determined the type of saggers suitable for pilot-plant operations.

Jan 1, 1959

By W. T. Westbrook

This Bureau of Mines report contains methods for analyzing iron are for total iron, ferrous iron, metallic iron, silica, manganese, aluminum, calcium, magnesium, phosphorus, titanium, carbon, sulfur, moisture loss, and ignition loss by wet chemical methods. Some are modifications of standard umpire methods; others have been developed by the Bureau of Mines to provide a com-bination of speed and accuracy. They are suitable for a high volume of samples and/or control situations, and for situations in which instrumental results must be verified. These methods have been used to analyze taconites, native ores, some foreign ores, and metallurgical products.

Jan 1, 1975

By John H. Soule

Appreciable quantities of sine and lead orus have been produced from the West. Pinos Altos district of Grant County, N. sex. This area was visited many times by engineers of the Bureau of ines. D. H. Johnson and 4. R. Storms visited the district in haren 1943 in connection with an acrenu road to toe wines. M. H. Storma again visited the area in July 1943 in connection with a hetals Feserve Corporation loan on the Routen-Thomas

Apr 1, 1948

By D. Bienstock, R. C. Kurtzrock, E. R. Bauer, J. H. Field

To remove hydrocarbons and carbon monoxide in automotive exhaust by oxidation , a catalyst of 4.2 percent Uз Og , 1.7 percent Cr₂ 0 , and 1.7 percent CuO supported on 1 /8 - inch y- alumina spheres was tested in a reactor in place of the muffler of a 1 / 2 - ton truck . Tests were made with both nonleaded and leaded gasolines . With the engine at operating temperature , tests were made with the engine idling and with the vehicle cruising at 30 mph . Auxiliary air was added to maintain an oxygen concentration of 3 to 4 percent in the gas leaving the catalytic reactor . The vehicle was operated for 83 hours (about 60 percent of the time with the engine idling ) and 525 miles with nonleaded gasoline . Conversions of 98 percent of the hydrocarbons and 100 percent of the carbon monoxide were achieved with the engine idling and with 7,000 ppm carbon atoms and 4- percent carbon monoxide in the feed to the reactor . Hydrocarbon conversions of 75 percent were obtained at cruising speeds of 30 mph with a feed of 1,700 ppm carbon atoms ; the carbon monoxide concentration was less than 0.3 percent in the feed and was unchanged in passage through the reactor . Identical activity was obtained initially in switching to a gasoline containing 1.9 ml tetraethyl lead (TEL) per gallon . However, there was a gradual loss in activity thereafter . Conversions in tests with the engine idling about 50 percent of the time , had decreased by 23 percent for the hydrocarbons and by 25 percent for the carbon monoxide from their initial values after 122 hours and 1,300 miles of operation with leaded gasoline . The levels of radioactive materials in the exhaust of the reactor and the radiation in the vehicle were negligible .

Jan 1, 1963

By W. K. Overbey

Knowledge of fracture systems in oil or gas reservoirs is essential to the efficiency of both primary and secondary production operations. A relationship was established between structural features of the surface and both natural and induced fractures in oil and gas reservoirs, thus providing a method of predicting the direction of rock fracture prior to field development and well completion. Correlations between the surface features and under-ground fractures resulted from analysis of joint strike measurements, bottom-hole impression packer surveys, photographs of hydraulically fractured wells, fracture data from oriented cores, in situ strain measurements from formation outcrops, and lineament analyses from aerial photographs. The mean orientation of surface fractures, lineaments, and stress field directions ranged from N 53° E to N 73° E, compared with an average orientation of N 63° E for the hydraulically induced fractures. Tectonic stress field was shown to influence the direction of hydraulically induced fractures. This report presents the details and application of techniques to obtain the orientation of the principal horizontal compressive stress field component and thus the direction of induced fractures.

Jan 1, 1971

By Bradley V. Johnson

The Bureau of Mines constructed a microminer--a scaled-down (5-by 5- by 11-foot) continuous-mining machine of the drum type with a unique triaxially controlled head--for use in a research program to study the effects of continuous-mining-machine parameters on the generation of respirable dust. This report describes field research with the microminer at the Bureau's Experimental Mine at Bruceton, Pa. Experiments were conducted to determine the effects of depth of cut, rotational speed, and sump and shear rates on the generation of respirable dust. The cutting forces were also monitored and compared with depth of cut. There appears to be a reduction in the amount of respirable dust generated when the depth of cut is increased or rotational is speed lowered, Variation of other machine parameters seems to have little effect on dust generation.

Jan 1, 1975

By William J. Campbell

The Federal Bureau of Mines provided five test materials--amosite, short-and long-fiber chrysotile, crocidolite, and nonfibrous tremo1ite--to the National Institute of Environmental Health Sciences (NIEHS) for studies on the biological effects of orally ingested asbestos-related materials. An inter-agency agreement between the Bureau and NIEHS made possible this program to characterize these test materials. The Bureau in turn received support through contracts with the Ontario Research Foundation for the milling of amosite and crocidolite, and with the University of Maryland for microscopic measurements. The five test materials, which were supplied in quantities of 960 to 1,200 pounds each, were characterized by chemical-instrumental analysis for elemental composition, surface area, density, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, mineralogy, and particle size analyses. Particle size distributions were emphasized because of the current theories relating adverse biological effects to length-width characteristics of durable elongated particles.

Jan 1, 1980