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By Harry R. Nicholls

A simple economical method has been developed for determining the in situ longitudinal and shear velocities in rock from which its elastic constants can be calculated. By detonating small charges of high explosives in shallow drill holes near a free surface, both longitudinal and shear waves were generated simultaneously. Accelerometers and velocity gages mounted to the rock surface were used to record the arrival time for both waves over travel path lengths from 50 to 450 feet, Measurements were made in two rock types. From the arrival time measurements, the longitudinal and shear wave velocities were calculated. From these velocities and the density of the rock, the elastic constants were calculated. The dynamic elastic constants of drill core samples of the two rock types were determined in the laboratory by the resonant-frequency method, The lab- oratory and in situ elastic constants are compared and significant differences noted. In general, there is less spread in the in situ data than in the laboratory data, and Poisson's ratio does not fall outside the theoretical limits for the in situ data as is often the case for laboratory-determined elastic constants.

Jan 1, 1961

By R. V. Ramani, R. Srikanth, R. Zhao

"A two-pan study was conducted to understand the factors affecting respirable dust generation potential or dustiness of coal seams. In the first part, the data from three prior comprehensive laboratory studies was analyzed to establish quantitative relationships between respirable dust generation potential and coal characteristics. This analysis indicates that respirable dust generation rate is positively correlated with Hardgrove Grindability Index (HGI), fuel ratio (fixed carbon/volatile matter), Vitrinite Reflectance (VR), and Level of Organic Metamorphism (LOM). In the second part, specially-designed single breakage experiments were conducted to determine the primary dust generation potential of 17 coal samples obtained from four continuous miner sections, three longwall sections, and the Penn State Coal Data Bank. The single breakage study indicates that primary dust generation rate is positively correlated with fixed carbon content, fuel ratio (fixed carbon/volatile matter), VR, and LOM. Since VR and LOM are strongly influenced by the process of coalification, differences in respirable dust generation rates in different coal seams may be explained by the thermal metamorphism of sedimentary organic matter during subsurface burial.Mineral particles in the range of one to five microns, if inhaled in sufficient amounts, lead to a number of lung diseases generally referred to as pneumoconiosis. A priori knowledge of the mechanisms and rates of fine particle generation during mining can aid in the development of more effective technology for controlling primary dust generation. Unfortunately, the data and knowledge currently available are not adequate for this purpose. In fact, a committee of the National Academy of Sciences on the measurement and control of dust concluded that the knowledge of the fundamental mechanisms by which coal mine dust is generated and a part of it is entrained in the mine atmosphere as respirable dust is not sufficient to clarify, let alone control, the processes involved (Anon., 1980). Under a research contract from the U.S. Bureau of Mines, Stecklein et al. (1982) have identified a number of fundamental research issues for understanding the coal fragmentation and entrainment processes.Reduction of dust generation is the best means of control since fine particles are difficult to control once they become airborne. Therefore, considerable research efforts have been directed to understand the factors influencing dust generation and entrainment, including machine design, water sprays, and ventilation. Laboratory studies have been conducted on the mechanical action of bits and machine power requirements (Evans and Pomeroy, 1966; Roepke, 1984). Since the physical characteristics of coal play an important role in the process of breakage, a number of laboratory studies have been conducted to study the relationship between coal characteristics and respirable dust generation (Baafi, 1977; Moore, 1986; Polat, 1990; Thakur, 1971). Several studies have been conducted on the relationships between coal characteristics and airborne dust concentrations (Hamilton and Knight, 1958; Khair and Xu, 1991; Organiscak and Page, 1993; Page et al., 1993). A limited number of studies have also been conducted on the relationships between coal characteristics and airborne dust concentrations in mines (Organiscak et al., 1990). Yet, no reliable method has been developed to rank coal seams according to their respirable dust generation potential. The conclusions derived from previous studies can be summarized as follows:"

Dec 1, 1996

By J. G. Kirby

According to the Bureau of Mines annual survey, as of January 1, 1954 there were 337 refineries with a total daily crude-oil throughput capacity of 8,006,897 barrels. The total daily capacity increased 368,236 barrels during the year while the total number of refineries declined 6. The capacity of the average refinery to process crude oil therefore increased during 1953 from 22,270 barrels to 23,759. With the exception of the Texas Inland, all refining districts reported gains in the installed capacity for the year, the largest being the Louisiana Gulf Coast with an increase of 20 percent. A total of 397,500 barrels of additional crude oil capacity was reported as under construction January 1, 1954. Accounting for 129,500 barrels of this total are facilities for 3 new refineries in North Dakota, 2 in Washington and I each in Ohio and Utah. Equipment being installed to replace existing units, totaled 180,750 barrels daily.

Jan 1, 1954

By J. W. Miller

Wyoming County had for many years supplied large quantities of coking coals to coke plants throughout the eastern United States and Canada. Up to the present most of the coal has been produced from relatively few beds, but in the future the coal will be produced from beds not previously mined in quantity. This trend is shown in the entire Winding Gulf field, of which Wyoming County is a part. This publication is one of a series of Bureau of mines reports appraising the Nation's coking coal, which y be used to determine the practicability of upgrading marginal deposits to metallurgical standards. This investigation of the preparation characteristics of Wyoming County coals is the third of the series undertaken in West Virginia.

Jan 1, 1955

By N. S. Dalal, X. Shi

"Electron spin resonance (ESR) measurements provide evidence for the formation of Cr(V) intermediates in the enzymatic reduction of Cr(VI) by glutathione reductase (GSSG-R) in the presence of NADPH, indicating an initial single-electron transfer step in the reduction mechanism. Depending on the pH, at least two different Cr(V) species are generated which are relatively long-lived. In addition, we have detected the hydroxyl (·OH) radical formation during the GSSG-R catalyzed reduction of Cr(VI) by spin trapping, employing 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and a-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) as spin traps. Superoxide dismutase (SOD) causes only a minor effect on the ·OH radical and Cr(V) formation, indicating that the ~ - is not significantly involved in the reaction mechanism. Catalase enhances the Cr(V) formation and substantially inhibits the ·OH radical formation, indicating the involvement of hydrogen peroxide (H20 2) in the reaction mechanism. Addition of H20i suppresses Cr(V) and enhances the ·OH radical fonnation. Measurements involving N-ethylmaleimide show that the Cr(V) species, produced enzymatically by the reduction of Cr(VI) by GSSG-R, react with H2O2 to generate ·OH radicals, which might participate in the initiation of Cr(VI) carcinogenicity.INTRODUCTIONC(VI) compounds have been found to exert serious toxic and carcinogenic effects on humans and animals [1-4) and to cause mutations in bacteria and transformation of mammalian cells [5-8). In contrast, most Cr(lll) compounds are relatively nontoxic, noncarcinogenic, and nonmutagenic [9, 10]. Cr(VI) and Cr(lll) oxidation states are different in their metabolic pathways: Cr(VI) ions are rapidly transported across cellular membranes [2, 11-13), while Cr(lll) moieties do not easily penetrate cells and are not oxidized by cellular constituents [3]. Since it is known that the reduction of Cr(Vl) is required for its reaction with DNA [2], the molecular mechanisms for the intracellular Cr(VI) reduction have been the focus of studies during the past decade but the details are still not understood."

Jan 1, 1990

By Carl Rampacek

The conversion of dilute sulfur dioxide gas into sulfuric acid by autoxidation in mechanical cells of the flotation or gas absorber types was investigated. Bench-scale tests were made with sulfur dioxide-air mixtures to determine the influence of several factors on autoxidation of sulfur dioxide, using iron and manganese salts as catalysts. The laboratory investigation subsequently was extended to pilot plant acid-making tests, using a modified turbomixer gas absorber having a 12-inch-diameter impeller. Sulfur dioxide gas was produced for the tests by roasting pyrite in a fluidized-bed reactor. In the better tests, made with manganese sulfate as the catalyst, the equivalent of 1,000 pounds of anhydrous H2SO4 was produced per 24 hours as a 10-percent solution; power consumption was 0.2 kwhr per pound of equivalent anhydrous acid synthesized. The batch and continuous tests demonstrated the technical feasibility of producing dilute sulfuric acid by autoxidation of sulfur dioxide gas in mechanical cells when converting pyrite roaster or waste smelter gases.

Jan 1, 1963

By M. M. Wong

Electrolysis of titanium carbide and a material consisting of titanium, carbon, nitrogen, and oxygen as soluble anodes in Used electrolytes was investigated by the Bureau of Mines for the preparation of crude titanium metal. Tests made in all-chloride electrolytes showed only a low recovery of titanium as well as a substantial volatilization of titanium trichloride (TiC13) when present in the electrolyte. Electrolysis at 750° to 850° C in a mixture containing 85 percent NaC1-15 percent potassium floutitanate (K2TiF6) yielded as high as 91 percent recovery of titanium from titanium carbide and 62 percent recovery of titanium from the titanium-carbon-nitrogen-oxygen material. Problems associated with the preparation of crude metal by fused-salt electrolysis are discussed. The crude metals produced from both anode materials were electrorefined in a sodium chloride-titanium chloride (NaCl-TiC12) electrolyte, and ductile titanium metal was obtained.

Jan 1, 1963

By H. D. Kline

Manganese ores have been mined in the Batesville district since 1849. Although not continuous over the intervening years, production had totaled approximately 432,000 tons of manganese ore and ferruginous manganese ore to the end of 1953. The ores occur in deposits, essentially low in manganese content, distributed over an east-west belt 24 miles long and 4 to 8 miles wide, the core of which is about 6 miles north of Batesville, Independence County. Although the reserves of high-grade ores in the district are comparatively small, the large deposits of subgrade ores and low-grade manganiferous material comprise potential sources of supply of manganese that may have increasing future importance. The manganese occurs as primary oxide and carbonate minerals in relatively flat-lying limestone and shale formations in which they were originally deposited and as oxides in residual clays resulting from decomposition of the shale and lime-stone. Most of the deposits underlie from a few to over a hundred feet of sedimentary chert, but many occur in the residual clays on exposed slopes of chert-covered hills.

Jan 1, 1956

By K. J. Miller

A two-stage froth flotation technique was developed in the laboratory to separate fine-size pyrite from coal. The process consists of the initial flotation of a 15-percent solids coal slurry with a minimum of frother; the coarse, free pyrite and other refuse are removed in the tailings. The froth product from this first stage is then repulped and treated with a coal depressant, a pyrite promoter, and a frother to float the remaining fine-size pyrite or pyrite attached to coal particles. With the two-stage process, the pyritic sulfur content of a Lower Freeport bed coal sample was reduced from 1.78 percent to 0.75 percent in the first stage, and from 0.75 percent to 0.27 percent in the second stage with good clean coal recovery.

Jan 1, 1972

By W. C. Holliman

This report on the characteristics of commercial aviation gasolines is one of a series of such reports. It presents compilations of' inspection data furnished on their products by 15 manufacturers of commercial grades of aviation gasoline and special data obtained in Bureau of Mines laboratories on 68 samples of these gasolines. Data are presented for 18 samples of grade 80, 20 of grade 91/98, 21 of grade100/130, and 9 of grade 115/145 aviation fuels. The gasolines are designated January 1948 production, although some of the samples actually were produced at a later date.

Jan 1, 1948

By I. L. Feld

This Bureau of Mines report describes the development of a simple method of producing low-phosphorus hematite concentrates from certain submarginal southeastern iron ores. The investigation was undertaken to obtain additional information on the Clinton iron ore outcrops at the southwestern extremity of the Birmingham district of Alabama and to assist in the development of operating techniques that would make it profitable to use the marginal ores of this area for blast-furnace feed. Batch and continuous pilot-plant tests demonstrated that a relatively simple wet scrubbing treatment) followed by a desliming operation to reject argillaceous (clayey) gangue, consistently yielded a marketable granular hematite product. Iron losses were relatively high but could be tolerated in view of the low treatment cost.

Jan 1, 1960

By C. R. Nisewanger, F. W. Brown

"The velocity of detonation of an explosive is one of its most important properties, because its performance depends markedly on the rate at which it releases its energy. Fortunately, the velocity of detonation is one of the few properties of an explosive that can be measured precisely. However, the velocity of detonation of an explosive may depend on several factors other than its chemical composition, such as density, physical state, degree of confinement, nature of confinement, and magnitude of initiating impulse. Presumably for an explosive of fixed chemical and physical properties there are certain limiting conditions of confinement and initiation under which the explosive will detonate at a maximum constant and uniform velocity. This velocity is its ""ideal"" velocity of detonation. It is obvious, however, that in order to evaluate performance properties of an explosive in all of its applications it may be necessary to measure its velocity of detonation under a number of conditions in which the velocity of detonation is far from the maximum ""ideal"" velocity.. Under certain-conditions the velocity of detonation may even,be,different at different points in the explosive.It is .relatively simple to determine the velocity of detonation of an explosive under a. standard set of conditions if one is free to use large quantities of the explosive and to form it into a convenient shape. Under these circumstances; one can use a thin column of explosive a meter or more in length. The time required for an explosion to travel the length of the column will not be less,of the order a few ten-thousandths of a second and can be readily and accurately measured .by means of the standard spark chronograph or by photographing the explosion with a rotating-drum camera. However in many applications the explosive charge may be of relatively small dimensions arid may not be in a form convenient for making velocity measurements and often may be enclosed in a case or other confining medium. It may be necessary to determine the velocity of detonation over distances of the order of a few centimeters, in which case the time intervals to be measured will be extremely small. For example, the time required for an explosion to traverse 1 centimeter of tetryl is of the order of 1.5 microseconds.Since no satisfactory method of determining time intervals of the order of magnitude of a few microseconds within an explosive charge was available,, at least not for all conditions that might be encountered in practice, it was necessary to develop a special electronic chronoscope which is capable of measuring time intervals as small as a microsecond with a fair degree of accuracy. This report describes the chronoscope and its application to measurements of velocities of detonation in explosives."

Mar 1, 1946

By Robert H. Bedford

As a result of the Bureau's general survey of quicksilver deposits in California, the Guadalupe mine area was among those chosen for exploration. Exploration, such as that at the Guadalupe, was aimed primarily at maintaining or increasing production of quicksilver during the critical wartime period. The project as originally planned contemplated sampling the dumps and prospecting some promising surface exposures by bulldozer trenches. Salvage was the objective in the first case and new ore in the second. Later, a program. of diamond drilling was added, designed to add both to ore reserves and to geological information. This report summarizes the history, notes the location and physical features, mentions property and ownership, and presents a brief description of the mine. The geology is outlined, and the work done by the Bureau of Mines is explained and supplemented with accompanying maps. The work involved repairing 1-1/4 miles of roads; bulldozing 13 trenches by removing 2,345 cubic yards of dumps to provide for sampling; digging and sampling 9,284 linear feet of hand trenches, digging and sampling numerous test pits; and drilling 7 diamond-drill holes, totaling 1,000 feet. A total of 419 samples, including 10 percent check samples, were taken. Exploration work in California at the time of this project was under the direction of Spangler Ricker, supervising engineer of the California field office, the late Robert Bedford was in charge of the fieldwork on this project.

Jan 1, 1950

By V. E. Homme

Low- and high-temperature reduction techniques were employed by the Bureau of Mines in study of conditions favorable to the formation of massive titanium crystals. '1,1,2 low-temperature method, feeding molten sodium to solidified titanium lower chloride-sodium chloride, produced higher quality and high quantity crystalline metal. The percentage of crystalline titanium was increased with increasing reactor diameter, melt depth, and titanium dichloride concentration. The high-temperature technique, feed molten sodium to melts above 8000 C, producing needle-type crystals of lower quality and with less consistent results than the low-temperature method. Layers of titanium foil, sponge, fine needles, wool, and crusts of sin-tered granules were formed during the earl, -art of the low-temperature reduction, and massive crystals were produced beneath this barrier in the latter part of the reduction. Crystalline titanium having an average hardness of Bhn 76 and representing 58 percent of the total titanium was obtained. Lamellar crystals up to 1 1/2 inches long with a hardness as low as Bhn 54 were also produced. A second-stage reduction for reclaiming titanium from offgrade sponge is described. Titanium produced by this method was comparable in quality to that from sodium reduction of titanium tetrachloride.

Jan 1, 1966

By Lindsay D. Norman

Four chloride and seven fixed-nitrogen processes for recovering manganese from domestic resources are described. The chloride processes are divided into two classes (leaching and chloridization) depending upon the major operation responsible for converting the manganese minerals to the chloride from which manganese oxide products are obtained. The fixed nitrogen processes, all of which yield high-grade manganese oxide products, are essentially either leaching or roasting processes. The 11 processes include HC1 leach, HC1 chloridization, HC1 chloride volatilization, CaC12 chloride volatilization, NO2 leach, HNO3 leach, HNO3 ?NO2 leach, H3 ?CO2-H2O system leach, (NH4)2SO4 leach, (NH4)2SO4 roast , and ammonium salt roast .

Jan 1, 1963

By Lindsay D. Norman

Four chloride and seven fixed-nitrogen processes for recovering manganese from domestic resources are described. The chloride processes are divided into two classes (leaching and chloridization) depending upon the major operation responsible for converting the manganese minerals to the chloride from which manganese oxide products are obtained. The fixed nitrogen processes, all of which yield high-grade manganese oxide products, are essentially either leaching or roasting processes. The 11 processes include HC1 leach, HC1 chloridization, HC1 chloride volatilization, CaC12 chloride volatilization, NO2 leach, HNO3-NO2 leach, NH3-CO2-H2O system leach, (NH4)2SO4 leach, (NH4)2SO4 roast, and ammonium salt roast.

Jan 1, 1963

By Thomas J. Peters

In 1978, the U.S. Bureau of Mines and the U.S. Geological Survey completed a joint mineral survey of the Chemise Mountain and King Range study areas as mandated by the Federal Land Policy and Management Act of 1916, Public Law 94-579. The U.S. Bureau of Mines examined all identified mineral prospects and deposits; the results of these examinations are included in this report. The U.S. Geological Survey studied the regional geology, geochemistry, and geophysics; the results of these studies are available in USGS Map MF-1196. No mineral resources were identified in either the Chemise Mountain or King Range study areas; however, a high-grade silver and base-metal occurrence, and minor manganese resources were identified in between the two study areas, within the King Range Conservation Area. The only mining activity in either area was a placer gold prospect on Honeydew creek in the northeastern part of the King Range study area. Three samples from this prospect contained no gold. The Chemise Mountain and King Range study areas are in a mountainous region along the coast of northern California, 230 road miles north of San Francisco, and 70 miles south of Eureka by way of U.S. Highway 101, through Garberville and Redway. The Chemise Mountain study area consists of 3,941 acres; it includes the 2,598-ft Chemise Mountain, and the cliff-lined seacoast southeast of Shelter Cove. a resort and fishing village. The King Range study area consists of 39.764 acres northwest of Shelter Cove, and includes the northwest-trending King Range with elevations above 4,000 ft. The Chemise and King Range study areas are underlain by deep-water marine sandstones, shales, and minor pillow basalts of the Late Cretaceous and early Tertiary Franciscan Subduction Complex. Mineral production was 1,650 tons of manganese ore within a manganiferous bed overlying pillow basalt at the Queen Peak mine southeast of the King Range study area. However, no significant manganese resources were found in the Queen Peak area. The Point Delgada area, directly south of the King Range study area, has prospects with high grade copper, lead. silver, and zinc. Exposures are inadequate to estimate resources; however, the metals may be associated with Franciscan volcanism (volcanogenic). The Chemise and King Range study areas may contain similar economic silver-rich, base-metal deposits.

Jan 1, 1992

By Richard W. Watson

Card-gap and projectile impact sensitivity data are presented for a wide variety of explosive compositions tested at the Bureau of Mines in more or less standard test geometries. The results of both tests are in good agreement in that they provide the same sensitivity ordering for different subclasses of explosives. Least sensitive were homogeneous liquids that did not exhibit a tendency to undergo low-velocity detonation, ammonium nitrate-fuel oil, and most cast military explosives. Of intermediate sensitivity were pressed and powdered military explosives, cast pentolite, permissible and non- permissible water-based explosives, and one commercial two-component explosive. The most sensitive were permissible and nonpermissible dynamites and explosives susceptible to low-velocity detonation.

Jan 1, 1973

By M. C. Irani

This Bureau of Mines survey of methane emissions indicates that total daily emissions have declined from 227 MM ft3 in 1971 to 214.7 MM ft3 in 1973. The highest average daily emissions in million cubic feet per day observed in U.S. bituminous coal mines were, in decreasing order, Monongalia County, W. Va., 40.7; Marion County, W. Va., 23.1; Buchanan County, Va., 22.1; Washington County, Pa. , 12.4; Greene County, Pa. , 11.7; McDowell County, W. Va. , 11.4; Cambria County, Pa., 9.8; Jefferson County, Ala., 9.5; Wyoming County, W. Va., 6.0; Marshall County, W. Va., 4.8; and Indiana County, Pa., 4.8.

Jan 1, 1974

By William O. Vanderburg

This paper describing the practice at the Wolf Pongee concentrator at Federland, Colo., is one of a series on similar subjects being published by the United States Bureau of Mines. The author acknowledges the assistance of Loach, manager of the Wolf Tongue Mining Co., and of W. G. Roseborough, superintendent of the golf Tongue mill, in the preparation of this paper.

Jan 1, 1933