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By N. S. Dalal, A. H. Hoffman, X. Shi, D. E. Banks, J. K. H. Ma, Y. Rojanasakul

Excessive production of reactive oxygen radicals by alveolar macrophages is proposed to play an important role in oxidative lung injury. A major product of oxygen radical formation is the highly reactive hydroxyl radical (•OH) generated via a biologic Fenton reaction. In addition to its known ability to induce lipid peroxidation, recent studies have suggested that the •OH may exert its cytotoxic effect through the alteration of [Ca2+], homeostasis. To test this potential mechanism as well as to investigate the relationship between •OH and Ca" overloading in cytotoxic injury, isolated rat alveolar macrophages were exposed to externally generated radical system, H2O2 (0.01 to 1 mM) and Fe (1 mM) and their [Ca2+] levels and cell injury were monitored using quantitative fluorescence microscopy with the aid of the specific Ca" indicator, Fura-2, and membrane integrity indicator, propidium iodide. Electron spin resonance measurements using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) confirmed the production of the .OH radical by this system. Upon the addition of the radicals, the macrophages displayed a rapid initial rise in [Ca2+] which was followed by a slower but more pronounced [Ca2+], elevation that reached a level 3 to 5 times higher than the basal level. This process preceded cell death as evident by nuclear propidium iodide fluorescence. Depletion of extracellular Ca" inhibited both the [Ca2+], response and cell injury. Preincubation of the cells with the Ca" channel blocker verapamil or .0H radical scavenger mannitol similarly inhibited the [Ca2+], rise and loss of viability. Firefly luciferase assay of cellular ATP content demonstrated that the alterations in [Ca2+], following .0H treatment preceded the depletion of ATP. Changes in membrane potential caused by Na* substitution with K* had no significant effect on either the unstimulated or stimulated [Ca"], levels. Taken together, these measurements indicate that .OH-induced injury in alveolar macrophages is associated with the alteration in [Ca2+], homeostasis. The mechanism of •OH-induced [Ca2+] loading is not due to nonspecific membrane damage or energy depletion, but mainly due to an increase in Ca2+ influx through Ca2+ selective channels. This Ca2+ over-load state as well as energy depletion caused by the oxidant may activate certain cellular degradative processes leading to cell injury and death.

Nov 1, 1995

By J. J. Rutledge, C. A. Herbert

In 1916 the Bureau of Mines, the Illinois Geological Survey, and the University of Illinois, working under a cooperative agreement, began an investigation of the subsidence of the surface above coal- mining operations. Four widely separated places where mining was in progress were selected as observation stations-one in the northern Illinois longwall coal field, one in the central Illinois coal field where the room-and- pillar panel system of mining was being used, and two in the thick coal of southern Illinois where the room-and-pillar panel system of mining was employed. These four points of mining activity gave a rather wide opportunity for observing subsidence when different mining methods were used. The four places selected for investigation of surface subsidence due to coal mining have been designated as follows: 1. A, in the northern Illinois longwall coal field, where the coal company has been operating coal mines for 30 years and where long- wall advancing is the only method of mining. 2. B, in Perry County, where panel room-and-pillar mining of a thick seam of coal is in progress and where mining operations have been carried on about 40 years. 3. C, in Macoupin County, where the coal company has been min- ing coal by the panel room-and-pillar method for about 15 years. 4. D, in Franklin County, where the coal company has been mining coal for 10 years by the panel room-and-pillar method.

Jan 1, 1927

By L. G. Marshall

The geology, mining, beneficiating, types of products, and costs in terms of percent of total costs and of labor, power, and supplies of two crushed-limestone operations in Madison County, Iowa, are described in this paper. The operations are basically similar, differing in refinements in mining, product types, and markets. The operations are comparable as to personnel and as to weighted costs in terms of percent of total costs and in terms of man-hours, power, and sup-plies. The waste-to-stone stripping ratio is 1 to 0.8 at both operations, the powder factor is 0.29 pound of explosives per ton of stone, and daily production is 95 tons per man-shift. Both companies use crawler-mounted diesel shovels for loading, truck transportation, wagon drills, and dry screening.

Jan 1, 1963

By Robert W. Metcalf

The feldspars are a series of related aluminum silicates containing varying proportions of potash, soda, rind lime; smaller amounts of other minerals arc likely to be present as impurities. They comprise three principal types: Potash spars, microline and orthoclase (KA12Si208); soda feldspar or albite (NaA1Si308); and soda-lime e (plagioclase) fellspars. The last-named is an intermediate group ranging from albite through oligoclase, andesine, labradorite, and bytownite to anorthite or line feldspar (CnA12Si2O8), Minor varieties are barium feldspar or celsian and a potash-barium feldspar. Perthite is a mixture of orthoclase end albite in alternate layers. Graphic granite or "corduroy spar" is an intergrowth of feldspar and quartz characteristically in the ratio of 3:1. Cornwall stone is a natural mixture of feldspar, quartz, end kaolinite imported in former years in sizable quantity from Cornwall, England. (A similar synthetic mixture, including some fluorspar, has been blended and marketed in the United States as "Carolina stone".)

Jan 1, 1941

By Jack D. Ramsdell

The objective of this investigation was to make a preliminary evaluation of titanium-vanadium-zirconium, alloys using room-temperature tensile properties as criteria for selecting promising alloys for future critical studies. Arc-melted titanium-vanadium-zirconium alloys ranging in composition from 5 to 20 a/o (atomic-percent) vanadium and 5 to 30 a/o zirconium, were investigated to evaluate hardness, hot workability, and room-temperature tensile properties. Metallographic examination coupled with hardness measurements were used to follow structural changes and aging response. Room-temperature tensile properties were criteria for evaluating mechanical and engineering properties of the alloys.

Jan 1, 1960

By J. M. Singer

Quenching distances for flames of methane-coal dust mixtures were determined with air and oxygen-enriched air. Coals used were Pittsburgh, Sewell, and Pocahontas No.3. Quenching distances were greater for flames of hybrid mixtures of coal dust and methane than for methane flames of corresponding stoichiometry. From the data of quenching distances and methane-coal dust concentrations was calculated the quenching equivalence, which is the increase in coal dust concentration required to maintain a given quenching distance value as the methane concentration decreases. These equivalences could be useful in identifying hazardous methane-coal dust mixtures in mines.

Jan 1, 1966

By E. G. King

This report contains experimentally determined heat-content values for cerium dioxide and Columbium (niobium) dioxide in the temperature range from 298° to 1,800° K. There are no previous similar data for Columbium dioxide, and those for cerium dioxide have an upper limit of 373° K. The heat-content and corresponding entropy-increment data are presented in tabular form. Equations were derived to represent the heat contents and heat capacities. The data for cerium dioxide are entirely regular, but those for columbium dioxide show two previously unreported anomalies at 1,090° and 1,200° K.

Jan 1, 1961

By R. J. Heemstra

A continuous flowing paper electrophoresis cell was used to separate petroleum and petroleum extracts into characteristic patterns. The electrophoresis of Bachaquero, Lagunillas, Boscan, and Gibson petroleums in nitro-benzene and acetic acid-based electrolytes was investigated. The extent of separation in the patterns was studied by measuring the metal and porphyrin contents of the effluents. Qualitative separations were achieved in some systems, whereas either system demonstrated only a high degree of electrophoretic migration.

Jan 1, 1967

This Part is concerned with the theoretical study of UHF radio communication in coal mines, with particular reference to the rate of loss of signal strength along a tunnel, and from one tunnel to another around a corner. Of prime interest are the nature of the propagation mechanism and the prediction of the radio frequency which propagates with the smallest loss. Our theoretical results are compared with measurements made by Collins Radio Co. This work was conducted as part of the Pittsburgh Mining and Safety Research Center's investigation of new ways to reach and extend two-way communications to the key individuals that are highly mobile within the sections and haulage ways of coal mines.

Jan 1, 1974

By W. H. Ode

An investigation of standard methods for determining ash in low-rank* coals showed that generally 60 to 95 percent of the total sulfur in the coal is retained in the ash as SO3. This large sulfur retention causes a positive error in the determined mount of ash of as much as 6 percentage points for the coals examined, although it usually is 2 to 3 percentage points for lignites and about 1 for subbituminous coals. Unless the sulfur content is low or unless a correction is made for the SO3 retained, the fixed carbon and oxygen have an equivalent negative error when determined by difference; also other inaccurate analytical values occur when the data are calculated on an ash- free bas is. No simple modification of the ashing procedure was found that would reduce the sulfur retention to a point where its effect on the ash determination would not be significant, Therefore, for accurate analytical work on law-rank coals, the SO3 should be deducted from the determined ash to obtain a "corrected" ash value.

Jan 1, 1962

By B. J. Dalton

The Bureau of Mines Helium Research Center has developed a computer program for solving two-phase equilibria data for binary mixtures and for evaluating thermodynamic functions of interest, including all critical points. This computer program was used to calculate equilibrium points on the PVTu surface for the helium-nitrogen system as predicted by the Van der Waals equation of state. Numerical values are tabulated and illustrations are presented for 1,279 equilibrium points and for quantities needed to construct Ponchon diagrams. Equilibrium ratios as a function of pressure at constant temperature and of temperature at constant pressure-are also shown graphically. In addition, saturated partial molal volume and partial molal enthalpy data are given. It is shown that the Van der Waals helium-nitrogen system exhibits retro-grade condensation of the second type for liquid helium concentrations of about 0.07 mole fraction or less and pressures below about 45 atm. It is also shown that the critical point is at a -maximum value of pressure (at constant temperature) and of temperature (at constant pressure).

Jan 1, 1971

By A. Wahab Khair, Richard D. Begley

"This paper presents results of destructive tests performed on rectangular coal specimen under the influence of two vertical and simultaneous wedge indentation forces. Several wedge designs and spacings were utilized in compression tests. The objective of these experiments was to qualitatively monitor the effect of different wedge designs and spacings on the stress distribution within the coal specimen.Coal samples from the Waynesburg coal seam were cut and trimmed to cubical dimensions of approximately 5 X 10 X 20 cm. These specimen were subjected to parallel compressive forces through two vertically applied wedge indentors. Loading was achieved with a hydraulic hand pump in order to facilitate interferogram construction. The load increments were limited due to the sensitivity of the holographic interferometric technique (holometry) in measuring small displacements; therefore, interferograms were taken only during similar increments in order to allow for a qualitative comparison between different wedge design and spacings. In some cases, interferograms were taken immediately before and after failure of the specimen.Introduction Failure Modes Three distinct modes of failure occur when geologic materials are subjected to wedge indentation forces. As shown in Figure 1, a crushed zone is located immediately adjacent to the indentor while chipping can occur if the fractures initiated in the crushed zone extend upwards to the free surface.. The third failure mode is a zone of intricate frac¬tures located between the crushed zone and the chipping zone. Several experiments have been conducted over the years to better understand crater formation and stress distribution within geologic materials under the influence of an indentor. Generally speaking, crack initiation and propogation observed in these experi¬ments correlate fairly well with wedge indentation theory; however, the nature of the .fractures is greatly influenced by different material properties such as grain size and cleavage planes. In other words, a wide range of behavior has been found in different rocks subjected to wedge penetration. For example, it has been observed that some rocks are merely crushed and indented while others are more prone to cracking and chip formation. Therefore, the development or nondevelopment of chips depends mostly on wedge geometry, rock type and depth of penetration. This work is part of the study associated with opti¬mization of cutting parameters, which is best modeled by using brittle materials and subjecting them to rigid wedge penetration tests."

Jun 1, 1988

By D. S. Harper, C. O. Carman

A German coal planer was put in operation in the Keystone mine of the Eastern Associated Coal Corp. , Keystone , W. Va . , in August 1960 . At present , the planer is mining in the fourth panel . The blocks of coal mined were 340 by 1,900 feet in panel 1 , 340 by 1,660 feet in panel 2 , 590 by 1,900 feet in panel 3 , and panel 4 , currently being mined , is 590 by 1,900 feet . Almost one- half million tons of coal have been mined from these four panels . An 11 - man crew handles the complete planer operation and produces an average of 500 tons of clean coal per shift . Self - advancing hydraulic props are used to support the roof over the entire face . Roof control and action on all of the panels has been highly satisfactory . During periods of extreme pressure , some additional support is required in the tail entry where evidence of weight from the retreating longwall extends about 200 feet outby the face . The time lost from production by moving equipment between panels has been reduced steadily . The move from panel 3 to panel 4 required 5 days , but it is believed that even that time could be reduced .

Jan 1, 1963

By E. D. Calvert

As part of its goal to minimize the requirements for critical and strategic minerals, the Bureau of Mines is conducting research to foster the use of domestically abundant materials such as molybdenum. This report describes the development of an investment shell molding technique that can be used to make castings of molybdenum and its alloys. The mold material is cubic Zr02 with a monoclinic Zr02 binder. The shell, formed by standard investment molding techniques described in the text, is prepared for molybdenum casting by firing for 6 hours at 1,550° C (2,822° F) or for 4 hours at 1,650° C (3,002° F). The resulting castings have predictable and reproducible dimensions with good detail. As-cast strength is poorer than the strength of wrought materials below 1,600° F. At and above this temperature, tensile strengths of cast and wrought materials are nearly equal. Aqueous corrosion of the castings in most media is insignificant.

Jan 1, 1982

By Russell R. Trengove

Core samples from an ore horizon 2,000 feet below the surface were successfully obtained by rotary drilling at the property of the Eureka Corp., Eureka, Nev. The ore was soft and friable; cores were not obtained previously with diamond drills. Whipstocking was used to get samples in a zone 200 feet from a vertical hole. A technique in shipstocking, by which the direction and deviation of the holes were controlled by means of nonfriction-type survey instruments, was successfully employed.

Jan 1, 1956

By Harry W. Campbell

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied parts of the 19,747-acre Lower John Day (OR-005-006) and 7,538-acre Thirtymile (OR-005-001) Wilderness Study Areas in order to evaluate their identified mineral resources. The study areas are located in Gilliam and Sherman Counties, OR, about 13 mi west of Condon. The area is underlain by the Miocene-age Columbia River Basalt Group. The Thirtymile study area is inferred to have 790,000 yd3 of subeconomic gold resources averaging 93.8 mg/yd3 gold ($1.21 yd3 at a gold price of $400 per oz) in two river bars. The Lower John Day study area has five river bars with gold occurrences totaling 1.0 million yd3 and averaging 13.5 mg/yd3 ($0.17 yd3) gold. A preliminary mining feasibility estimate suggests gold could be profitably mined in the study areas from placer deposits containing at least $3.83 yd3 in gold content. Stone, sand, and gravel occur in the study areas, but more accessible deposits are closer to regional markets. No mines or prospects are in or near the study areas; however, one lode mining claim, now abandoned, was located in the Thirtymile study area. Oil and gas leases cover both study areas.

Jan 1, 1987

By H. D. Jacobs

The Bureau of Mines undertook a research program to insure an adequate supply of iron raw materials for future iron and steel making needs. A sample was obtained of oxidized taconite from the western Mesabi Range in Minnesota, and the metallurgical response of the taconite to beneficiation by a process that included selective flocculation-desliming-cationic flotation was evaluated. The sample contained 35.3 pct iron and represented approximately 2 billion tons of crude material. Selective flocculation and flotation were evaluated in a pilot plant with a feed rate of 900 Ib/hr. Concentrates averaging 61.7 pet iron and 5.1 pet silica were obtained, with an accompanying iron recovery of 67.2 pet. About 83 pct of the process water requirements were reclaimed from the slime and froth tailing and then recycled.

Jan 1, 1980

By Roger J. Morrell

Disk-cutter experiments were performed on five rock types ranging in compressive strength from 9,000 psi to 27,000 psi. A specially constructed testing machine called a linear-cutter apparatus (LCA) was designed to load and traverse a free-rolling disk cutter across a sawed rock surface. The LCA was instrumented to measure the vertical and horizontal forces acting on the cutter during the run.. The ability of disk cutters to fragment rock was determined for both 60--degree and 90-degree cutting-edge angles, and relationships and regression equations were developed to predict cutter performance based on rock physical properties and applied forces,

Jan 1, 1970

By F. D. Stevenson

A metal diaphragm pressure relay system was constructed to measure vapor pressures of the metal halides, oxyhalides, and other substances at temperatures up to 700° or 800° C. The vapor pressure of arsenic (III) oxide (As2O3) was determined to verify the reliability of the apparatus for such measurements. The data for the liquid AS2 Os (2820 to 4830 C) are represented by the equation, log Pmm = 6.875 - 2,929/T, from which the normal boiling point was calculated to be 461° C. The heat of vaporization calculated from this equation was 13.40 ±0.09 kcal/g mole As4OS and is essentially constant over the interval studied. The melting point of the octahedral arsenic (III) oxide was determined to be 278° C from the inter-section of the solid and liquid vapor pressure curves, A thermal analysis apparatus is also described by which melting and transition temperatures could be checked by a method independent of vapor pressure data. The melting points of the monoclinic and octahedral forms were determined to be 314.4 ±1.4° C and 278 ±5° C, respectively.

Jan 1, 1963

By Michael G. Zabetakis, Aldo L. Furno, George H. Martindill

Hydrazine vapor is flammable in the absence of air at elevated temperatures and atmospheric pressure . The minimum concentrations of benzene , toluene , m- xylene , cumene , and n- heptane needed to inhibit flame propagation through vapor mixtures of hydrazine and hydrocarbon were determined at 125 ° C and atmospheric pressure . These concentrations can be correlated with either the heat of formation or the heat capacity of the hydrocarbon .

Jan 1, 1964