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Reduce the potential for injuries in underground mines by providing an alternative to manually lifting and holding heavy roof-support beams. The Problem I-beams, rail sections, and wooden cross-beams are often used in mine haulageways where extensive roof support is needed. Studies by the Bureau of Mines have shown that many mines must resort to manually lifting, moving and installing these beams. Such manual-handling activities have the potential for causing injury to mine workers, particularly back injuries. I-beams used for roof support can typically weigh from 400-500 lbs. Rail sections weigh about the same as the I-beams. Wooden beams can weigh from 200 to 300 lbs. To lift a single beam usually requires the efforts of 3 to 5 mine personnel.

Jan 1, 1988

By Natalie A. Sapola, Knox Van Dyke, Jean Rabovsky, Vincent Castranova, William H. Pailes, Melanie McPeek, Deloris J. Judy

"INTRODCJCTJONPlatelet activating factor (PAF) is a glycerophospholipid (1-0-alkyl-2-acctyl-sn-glycerol-3-phosphoryl choline) which has been shown to mediate a broad range of biological activities. 1·3 Its pulmonary actions include contraction of pulmonary tissue,4 secretion of leukotrienes from leukocytcs,5 airway constriction,6 pulmonary edema,7 and enhanced migration of neutrophils into the airspaces of thelungs.8-9PAF can be released from several different cell types, such as, basophils, neutrophils and alveolar macrophages, in response to a variety of particulates or membrane stimulants which include zymosan, calcium ionophore, phorbol esters, chemotactic agents, and endotoxin. 1~1 3 Therefore, PAF may play an important role in the development of pneumoconioses by mediating pulmonary responses of lung cells to a variety of occupational dusts. To investigate this possibility, we determined the effects of P AF on several physiological parameters of neutrophils, alveolar macrophages, and alveolar type Il epithelial cells.METHODSIsolation of CellsNeutrophils were isolated from human blood by dextran settling and centrifugal elutriation.14 Isolated neutrophils (93% pure) were resuspended in HEPES-buffered medium (145 mM NaCl, 5 mM KCI, 10 mM HEPES, 5 mM glucose, and 1 mM CaC12; pH = 7.4). Cell number and volume were determined with an electronic cell counter equipped with a sizing attachment.Rat alveolar macrophages were obtained by pulmonary lavage with ea2+, Mg2+-free Hanks balanced salts solution. 15 Alveolar macrophages (94% pure) were resuspended in HEPES-buffered medium, counted, and sized electronically.Rat alveolar type Il cells were isolated by enzymatic digestion for 35 minutes at 37°C with 40 µ/ml type I elastasc and 0.1 % collagenase and purified by centrifugal elutriation. 16.17 Type Il cells (92 % pure) were resuspended in HEPES-buffered medium for measurement of membrane potential, oxygen consumption, and trypan blue exclusion. Type Il pneumocytcs were resuspended in 0.1 M NaCl plus 0.05 M HEPES (pH = 7.8) to measure cytochrome P450-dependent activities and aggregation. Cell size and number were determined electronically."

Jan 1, 1990

By Andrew B. Cecala

The Bureau of Mines conducted a brief laboratory study on the 10-mm diam Dorr-Oliver nylon cyclone to investigate (1) whether high wind speed (>300 ft/min), or sampler inlet orientation with respect to wind direction, can introduce errors when sampling respirable dust, and (2) whether any such errors can be reduced by using an inlet shield. Being preliminary in nature, the study was not structured to produce definitive results, but rather to discern likely trends and to indicate whether or not a more in-depth study of the problem is warranted. Photometric mass sensing measurements suggested that as the wind velocity increased, the cyclone sampling directly into the high-velocity airstream tended to oversample, relative to the cyclone sampling in a low-velocity airstream. Orientation of the sampler introduced measurable differences in sampling efficiency at higher wind velocities. A shield placed around the cyclone diminished the effects of wind velocity and sampler orientation on sampler performance. Results of this work offer sufficient evidence to substantiate the need for a more in-depth study.

Jan 1, 1983

By D. Harrington

A uniform hoisting-signal code for mines hoisting from more than one level, if adopted by all mining States, would be beneficial to employees and owners alike and should largely reduce the number of hoisting accidents. Misunderstood hoisting signals cause many shaft accidents involving injuries to men, damage to equipment, and loss of production from the resultant delay. Many of the metal-mining States have adopted codes for hoisting that are effective within the borders of that State but usually entirely different from the signal code, if any, in use in an adjoining State. For many years safety engineers have recognized this lack of uniformity as a distinct hazard, but a uniform code has never been adopted by the States or by the mining industry in those States that have not incorporated signal codes in their mining laws or mining regulations.

Jan 1, 1944

By Warren E. Morrison

INCREASED production and utilization of minerals fuels and power accompanied the overall expansion in U.S. economic activity during 1963, which saw continued advances toward higher production, employment, and purchasing power. During 1963, record levels of wages, profits, and consumption were attained, while costs and prices maintained the stability exhibited throughout most of the recovery period. Expanding industrial production, the average index of which went from 118.3 in 1962 to 124.3 in 1963, narrowed the gap of unused manufacturing capacity to an estimated 5 percent. Gross national product (GNP), another major indicator of economic activity, reached a record level of $583.9 million (current dollars) during the year, this being $27.7 billion, or 4.9 percent above 1962. These achievements were somewhat marred by unemployment, which remained at 5.5 percent of the labor force in 1963, and the continued deficit in the U.S. balance of payments. Against this general background, total national consumption of energy resources for the year was equivalent to 49,816 trillion British thermal units (Btu), an increase of 4.2 percent over 1962. This represented a somewhat lower rate of growth than for GNP during the year.

Jan 1, 1964

By Lindsay D. Norman

Computer models for simulating the construction and for calculating the properties of particulate solids in two- and three-dimensional systems (coverings of circles and packings of spheres, respectively) were developed. By simulating the physical process of constructing circle coverings and sphere packings, in which the circles or spheres were randomly selected from many different distributions of sizes, physically realizable loose random assemblies were simulated whose physical and geometrical properties were predictable with the computer. Many of these properties, such as the number of contacts, are extremely-difficult to measure accurately, or considerable ingenuity is required in their determination. All of these properties were easily and accurately calculated by the computer models for many different coverings and packings constructed from equal, discrete, uniform, and log-normal distributions of particles. In addition to the loose random assemblies, dense random covering and packing constructions were simulated whose properties are ideal upper limits for those of the loose random coverings and packings. The properties of the dense random coverings and packings, heretofore only obtainable by theoretical analysis, were also simply obtained. The statistical geometry of loose random coverings and packings was studied, and several new interpretations of the area-covering or space-filling requirements in these systems were made. In two dimensions, it was found that the properties of all loose random coverings are predictable by taking suitably weighted averages of the corresponding properties of just four kinds of polygons whose edges are defined by connecting the centers of mutually tangent circles in the covering. The distributions of these polygons that permit area-covering were determined, and empirical equations for predicting the density, average coordination number, and average pore area in loose and dense random coverings were formulated. The properties of loose packings were determined by performing a simplicial division of the computer-simulated assemblies to produce a unique set of minimum volume, space-filling tetrahedra whose edges connected the sphere centers in each packing. A simple empirical equation was formulated that permits the calculation of the average number of contacts in any sphere packing, random or regular. Some of the statistical geometrical properties of the simplicial tetrahedra in the computer-simulated packings were analyzed. The tetrahedron edge length distributions in all the loose random packings were nearly identical when the edges were presented in terms of sphere diameters, regardless of the sphere population in the packing. Moreover, the gap lengths in the loose packings were to an excellent approximation representable by a uniform distribution of sizes. The distributions of spheres in tetrahedra resulting from the simplicial division of the loose random packings also existed in the tetrahedra in dense random packings. These observations were employed in developing a unique method for predicting the geometrical properties of loose random packings without simulating the assembled packing. Instead, the space-filling simplicial graph could be predicted for any given density of packing of any sphere population. The cumulative packing properties of these tetrahedra were shown to be nearly identical to those calculated by all loose random packing simulations attempted in this investigation. The simplicial tetrahedra completely describe a packing and can therefore be used to predict all properties of interest.

Jan 1, 1971

The Appalachian Mountains divide Pennsylvania into two distinct coal regions, bituminous and anthracite. The western region of the the state, where the majority of bituminous mines are located, is characterized by mountains and gently rolling hills. Bituminous coal seams underlie about 12,000 square miles in 28 counties. The anthracite coal region, located in the northeast, covers approximately 3,300 square miles. This area contains more than 20 different coal beds that vary in thickness from a few inches to 50 or 60 feet. The anthracite region is characterized by steeply pitching seams that require highly specialized mining techniques and present unique challenges for solving problems such as the mine subsidence associated with abandoned underground anthracite mines. For more than a century, coal has played a major role in the economic and industrial development of Pennsylvania, particularly the steel industry. Estimated bituminous reserves total 23 billion tons, or 5.3 percent of U.S. reserves, and anthracite reserves total 7.1 billion tons, or 97 percent of U.S. anthracite reserves. Pennsylvania received conditional approval of its regulatory program July 31, 1982. Pennsylvania's Abandoned Mine Land Program was approved on the same date.

Jan 1, 1992

By Jack Kadlecik

This final technical report describes the concept feasibility study, testing, design and development effort which went into. The quick opening enclosure access cover and flame path tolerance checking system. A detailed definition of the explosion-proof multiple start threads is shown for two (2) sized electrical enclosures.

Jan 1, 1972

By Stephen Krickovic

A degasification experiment was conducted in a Pocahontas No. 3 coalbed mine in Virginia. It involved (1) drilling holes in the coalbed in the out-side headings of a set of five being developed in virgin area, and (2) con-ducting a methane emission rate study as mining progressed and additional holes were drilled. Degasification from all drill holes except the longest in each of the outside headings and the first three drilled (excluding the in-situ pressure hole), was erratic and inconsequential in methane emission rates. The two longest holes liberated 66 and 79 cfm of methane, which is significant for the coalbed, but such quantity lasted a relatively short time; the first three were uniform but low in methane emission.

Jan 1, 1972

By V. F. Swanson

As part of the Bureau of Mines titanium resources examination program, samples of altered rock (saprolite) and unaltered rock from the Roseland anorthosite near Roseland, Nelson County, Va., were tested for amenability to beneficiation by flotation. A flotation technique was developed to produce bulk concentrates of ilmenite, rutile, sphene, and leucoxene. It was necessary to first float apatite using oleic acid as the collector, in an alkaline pulp with dextrine as a titanium mineral depressant. The titanium minerals could then be floated from the apatite tailing, using fluosilicic acid to depress the remaining apatite, morin to depress ferromagnesian minerals (when present), and oleic acid as the collector. A bulk titanium mineral concentrate, analyzing 66.0 percent Ti02 and 0.08 percent P205, was obtained from a sample of the unaltered rock which contained 5.45 percent TiO2 and 2.81 percent P205. Overall recovery in the concentrate was 47.1 percent of the total TiO2 in the ore. About 55 to 65 percent of the saprolite sample was clay and was removed by attrition scrubbing and decantation. The apatite prefloat procedure was applied to the saprolite sands; subsequent titanium mine: 1 flotation recovered 72.2 percent of the Ti02 in a bulk concentrate containing 65.1 percent TiO2 and 0.20 percent P205.

Jan 1, 1962

By Nan C. Jensen

Silica, the world's most abundant mineral compound, is composed of the two commonest elements - oxygen and silicon. In addition to being the life-giving constituent of the atmosphere and the major element in the waters of the earth, oxygen comprises almost half of all known terrestrial matter and occurs combined with most of the other ninety-odd elements in the solid crust of the earth; however, a large proportion of the oxygen is combined with silicon. Silicon is second only to oxygen in abundance in nature and constitutes more than one-fourth of all known terrestrial matter. The compound of oxygen and silicon, called silicon dioxide or silica, forms 59.08 percent of the earth's outer 10-mile crust. Some of the silicon dioxide exists as

Jan 1, 1942

Bitumninous and semianthracite coal reserves underlie about 1,400 square miles of Arkansas, less than 2.7 percent of the state's total area. These deposits, located near the western border, contain an estimated 2.2 billion tons, of which about half are recoverable. This represents less than one-tenth of one percent of the national reserves. Most of the commercial coal is mined from thin beds that are at least 14 inches thick. In some locations, however, the coal beds can be as much as eight feet thick. Lignite was mined in southern Arkansas before the Civil War. Current estimates indicate that the reserves may be as high as 9 billion tons, which could be used in the state's coal-fired electric generating plants; however, these deposits are not being mined at present. Because many coal operations in Arkansas are small and the demand for coal is unsteady, the industry employs fewer than 25 miners on a daily basis. Arkansas gained primacy when its regulatory program was conditionally approved November 21,1980, subject to the correction of four minor program deficiencies. The regulatory program was fully approved January 22, 1982. Authority of the state to administer its Abandoned Mine Land Reclamation Program was granted upon approval of the Arkansas Reclamation Plan on May 2, 1983. Arkansas was the first state to assume responsibility for abandoned mine land emergency projects when its Reclamation Plan was approved.

Jan 1, 1992

By G. Richards Gwinn

The mineral olivine, though known to mineralogists for many years, was of little commercial value in the United States before 1933. It was first described in 1790 by Johann Gottlieb Werner, who named it "olivine in allusion to its olive-green color. Commercial olivine first attracted attention because of its refractory properties. Further research has developed methods of extracting the magnesia content for the production of various magnesium compounds. Experimental and pilot-plant work also are in progress to make olivine available as a low-cost raw material for the production of magnesium metal.

Jan 1, 1943

By J. Bennetts

As part of its mission to develop technology that will help increase the supply of critical and strategic minerals from domestic resources, the Bureau of Mines has investigated methods for beneficiating platinum-group metal ores from the Stillwater complex, Montana. This report presents the result of a bench-scale study employing froth flotation to recover a sulfide concentrate containing platinum-palladium values from a mineralized gabbro. Best results were obtained with a flotation scheme utilizing a mercaptobenzothiazone collector and sulfuric acid. Rougher concentrates containing approximately 11 oz Pt-Pd/ton and 90 pct of the metal values in the ore were obtained. Subsequently, cleaner concentrates containing approximately 26 oz Pt-Pd/ton and between 80 to 85 pct of the Pt-Pd values in the ore were prepared.

Jan 1, 1980

By Peter J. Clarke

The Soviet-controlled Government in Afghanistan continued to emphasize development of the country's mineral resources, primarily to supply raw materials and fuel to industrial areas in the Soviet Central Asian republics. In addition to expanding production of natural gas for export to the U.S.S.R., a $600 million2 Soviet-Afghan cooperation project, 1 of 167 such projects established since 1981, was devoted to exploiting the Ainak copper deposit, south of Kabul in Logar Province. Also being developed was the large Hajigak iron ore deposit in the Hindu Kush Mountains, 100 kilometers northwest of Kabul. In addition to these minerals, Afghanistan already produced small quantities of barite, cement, coal, gypsum, salt, and possibly some lapis lazuli. Afghanistan was the world's leading producer of lapis lazuli, a semiprecious gem stone, prior to the Soviet invasion in 1978, but production, although no longer reported, has probably been significantly reduced. It was also reported that Soviet mining engineers and technicians have commenced producing uranium from Lashkangah in the mountainous Khawaja Rawash area near Kabul.3 The Government was also considering mining chromite from Herserak and Mohammed Agha Kulanger, near the border with Pakistan.4 Afghanistan's overall economy remained stagnant in 1983, a result of continuing armed resistance to the Soviet-installed government. The gross domestic product (GDP) was estimated at about $2.8 billion, only marginally higher than the 1982 level. The value of exports was estimated at $720 million, up less than 2% over that of 1982, while imports rose approximately 8% over the same period. Natural gas was by far the leading export, earning about $295 million, up 4% over that of 1982. Approximately 90% of Afghanistan's natural gas production was exported to the U.S.S.R. Gas exports were used to pay the country's debt to the U.S.S.R., and also to pay for its supplies of petroleum products and other goods, which were imported almost exclusively from the Soviet Union. Some of Afghanistan's petroleum products were supplied by the U.S.S.R. as grants in aid, as Afghanistan did not have any domestic petroleum refining capacity.

Jan 1, 1985

By W. T. Abel

The rate of the steam-carbon reaction, which is of fundamental importance to coal gasification, was determined by passing steam over graphite specimens suspended in an electrically heated tube. The measurements were made at 1,900° to 2,400° F. and at steam-feed rates of 0.1 to 2.0 moles of steam per mole of carbon per minute. At the maximum steam-feed rate, the reaction rate of carbon ranged from 0.4 percent per minute at 1,900° F. to 7 percent per minute at 2,400° F. Up to about 2,200° F., the steam-feed rate had only a slight effect; above this temperature, it limited the reaction velocity when the final mole fraction of steam in the reaction products was much less than 1.

Jan 1, 1962

By James P. Rider, Charles D. Taylor, Edward D. Thimons

Research was conducted to investigate how ventilation of a mining face is affected when scrubber flow is greater or less than intake flow. Tests were conducted in a full-scale surface test gallery built to simulate a mining entry with a continuous mining ma- chine at the face. Methane gas was released at constant flow at the mining face. Gas measurements taken at six locations near the face were used to evaluate how well the face was being ventilated. Increasing scrubber flow resulted in lower methane levels even when scrubber flow was much greater than intake flow.

By F. D. Sutterfield

This study was conducted to provide experimental evidence on the effect of modifications of gasoline front-end composition on the photochemical specific reactivities of automotive emissions. Evaporative and evaporative-plus-exhaust emissions from an automobile operated with four fuels of different volatility and varying levels of C.-C5 olefins were irradiated in a 10040 environmental chamber at three sets of initial hydrocarbon-nitrogen oxides concentrations. Reactivity was measured and expressed in terms of rate-of-NO2 formation and dosages of oxidant, peroxyacetyl nitrate, and formaldehyde. The compositional changes that were necessary in reducing fuel volatility were found to have no significant effect on the reactivity of the emissions. However, replacing C4-C5 olefins with saturated components resulted in sharp decreases in all reactivity manifestations observed for the evaporative emission samples. A lesser influence (of C4-C5 olefin replacement) was found with the composite exhaust-plus-evaporative samples; the effect that was observed could be attributed to the evaporative emission portion of the sample. The data therefore suggest that saturation of front-end fuel olefins had no large effect on exhaust emission reactivity.

Jan 1, 1971

By Geo. S. Krueger

This paper, describing mining methods and costs at the Judge mine Park City, Utah, is one of a series being prepared by the Bureau of Mines on mining practices in the United states. ACKNOWLEDGMENTS The writers acknowledge the assistance of E. D. Gardner, supervising engineer, Southwest Experiment Station, Bureau of Mines; Paul H. Hunt, mine manager, Park Utah Consolidated Mines Co.; Wm. Osika, chief mine accountant; and Eric Neilson, assistant master mechanic of the mine.

Jan 1, 1938

By Ann C. Kim

This Bureau of Mines report summarizes the methods and results of many of the laboratory studies on spontaneous heating of coal published in the last 50 years. It includes a brief description of experimental methods, indices of combustibility, and important contributing factors. Adiabatic calorimetry, isothermal calorimetry, [0], sorption systems, or temperature differential are the most frequently used experimental methods. Indices of combustibility include various heating rates, crossing point temperature, ignition temperature, and CO index. Factors that affect the spontaneous heating of coal include air flow rate, changes in moisture content, particle size, rank, temperature, pyrite content, geological factors, and mining practice. Experimental conditions and results from 20 papers are summarized in an appendix, and the bibliography contains 45 references.

Jan 1, 1977