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Hydraulic fluid power systems are advantageous whenever power output must be accurately and safely controlled. The load movers, cylinders, jacks, rotary actuators and hydraulic actuators in these systems can be made to smoothly and accurately start, stop, reverse, hold position or move steadily under heavy and variable loads or torques. Because hydraulic systems are simple, compact, reliable, and low cost compared to other power methods and because they can deliver controlled power anywhere on the machine to which a hose can be routed, they are a pan of almost every type of machine found on a coal mining section. Some of the functions they perform are positioning drill booms, driving drill pots on roof bolters, positioning curter booms, raising, lowering, and swinging conveyors, driving conveyors on continuous miners, raising, lowering, and applying sustained loads to longwall roof supports, and advancing the face conveyor and roof supports in longwall mining operations.

Jan 1, 1982

By O. H. Metzger

This is the second of two papers dealing with the construction and use of aerial tramways in the metal-mining industry. The first paper3/described aerial tramways in a general way and discussed the engineering principles used in tramway design. The purpose of this paper is to give a more detailed description of equipment and material rind to discuss construction and operating costs. ACKNOWLEDGMENTS The paper is based largely on data from actual operations. Metal-mine operators from many parts of the United States, Canada, Alaska, and Mexico contributed liberally.

Jan 1, 1940

With IIT research institute as a cosponsor, this seventh mineral waste Utilization Symposium was funded by the Bureau of Mines through its Division of Mineral Resources Technology. Environmental scientists and engineers from five countries (Canada, Netherlands, Austria, England, Guatemala) besides the United States participated in the symposium, which was held Oct. 20-21, 1980, at the Chicago campus of IIT Research Institute. Of the 25 papers presented on the reclamation and recycling of mining and mineral wastes, municipal solid waste, industrial waste, and scrap metal, 21 are summarized herein.

Jan 1, 1982

By R. W. Courtney

The objective of this study is to make a critical evaluation of the magnitude and extent of electrostatic hazards in typical U.S. mining operations and to assess the adequacy of techniques, materials, and equipment for detecting and minimizing these hazards. This was accomplished with an incident/accident survey, mine visits, literature search, and engineering analysis. It was concluded that it would be desirable to (1) utilize ground fault interrupters to minimize stray current from electrical utilities, (2) decrease the current and electrostatic sensitivity of electric detonators used in areas with a high incidence of lightning strikes or troublesome stray currents, (3) institute quality control and test standards for blasting material and protective devices, (4) establish an electrostatic monitoring program for loading ANFO in plastic lined holes, and (5) establish a risk criteria for operator exposure in mines.

Jan 1, 1982

By ALBERT E. HALL, Arno C. Fieldner, Alexander L. Field

As a safeguard against excessive clinker troubles, specifications for the purchase of coal can be drawn to include the "softening" or "fusing" temperature of the ash. The value of such information has been recognized by the Bureau of Mines and has induced the bureau to investigab~ laboratory methods of determining the fUSIbility of coal ash, and the bearing of the results on clinker formation in fuel beds. The bureau realized that the fusibility of a mixture of oxides and silicates snch as is comprised in coal ash ,'aries according to the conditions under which tests are made, and that in the absence of any generally accepted method, no agreement is to be expected among tests made in differ«:-nt laboratories. Indeed, Marks a has recently called attention to differences as great as 3900 C. that were obtained with the same sample of ash by two different laboratories. Therefore if a fusion-temperature clause is to have any place in specifications for coal, a standard m('thod of t('sting should be adopted in order to insure comparable results by different laboratories and to obtain the softening or fusing temperature of the ash unde:'r conditions similar to those of a fuel bed. After a consistent method has been devised for obtaining comparable:' results at different laboratories, there will remain the correlation of these results with those from the burning of coal in furnaces before the value of fusibility tests in coal specifications can hE' finally determined.

Jan 1, 1918

By Terry J. Close

The Welcome Creek Wilderness has small, dispersed gold placers. Pockets in the 25.5 million yd3 (19.5 million m3) of alluvium along Welcome and Rock Creeks have as much as $5.61 gold/yd3 ($7.34/m3) at $500/troy oz ($16.08/g). All the alluvium averages 20.1 cents gold/yd3 (26.3 cents/m3). Because of the low average gold content large-scale placer mining would not be economically feasible. Small-scale selective pocket mining, however, may be profitable. The alluvium along the streams in the Wilderness has little apparent potential for production of sand, gravel, or stone because alternate sources are closer to markets. The four lode prospects known within the Wilderness appear to have low mineral potential. No oil, gas, uranium, or geothermal energy sources are known to be present.

Jan 1, 1982

By Arnold M. Lansche

[Selenium and tellurium are rare elements in the earth's crust. Their scarcity and primary dependence of supply on copper and lead output are in consonance with the relatively small quantities consumed at 1964 level. Production depending on output of copper and lead creates a supply situation- which would appear to militate against development of large-scale usage of these elements. However, supplies have adequately met. demand in the past decade and can be increased substantially if warranted by new uses for either selenium or tellurium Ores of copper and lead re the principal sources of selenium and tellurium. Byproducts from the smelting and refining of copper and lead concentrates are incorporated in refinery anode slimes from which selenium and tellurium metal are recovered.]

Jan 1, 1967

By W. W. Adams

"The ninth yearly National Safety Competition covering the calendar year 1933, conducted by the United States Bureau of Mines, w participated in by 332 mines and quarries situated in 35 States. Enrollment represented as increase of 10 plants over 1932, and one addition was made to the number of States represented.The primary purpose of the United. States Bureau of Mines in conducting the contest is to promote safety in United States mineral industries. This purpose is accomplished directly through the efforts of the competing companies and their employees to win first place in the competition and thereupon receive recognition on a national scale for their achievement the purpose is accomplished indirectly through studies by the United States Bureau of Mines of the facts contained in the accident reports the competing companies furnish to enable the Bureau to compute the accident rates that are the basis for determining the winners of the contest.The statistics which constitute the basis for determining the winning companies and the relative standing of all companies are prepared uniformly without regard to the States in which the companies operate, or to differences in classes of accidents covered by State laws relating to compensation for injuries resulting, from industrial accidents.Bronze trophies, known as 'Sentinels of Safety', which were provided by The Explosives Engineer magazine to be awarded annually by the Bureau of Mines, were presented to five companies in the contest of 1933, each company having established the best accident-prevention record within one of the five classes into which all companies were divided, namely, anthracite-mining companies, bituminous-coal-mining companies, metal-mining companies, operators of nonmetallic-mineral mines other than coal mines, and quarries or opencut mines. The trophies are awarded for 1 year and are then transferred to the winners of the succeeding year's contest.The trophy for bituincus-coal mines was won by a company in Wyoming. A company in Tennessee won the trophy for metal mining. In the nonmetal-mine group the trophy was again won by a company in New York. A quarry in Michigan won the trophy for the quarry-and-opencut-mine group. The trophy for anthracite mines remains in Pennsylvania, as all anthracite mines in the contest are in that State."

Jul 1, 1934

By Jeffery L. Kohler

This final report on Bureau of Mines Contract J0338028 presents the results of a research effort to predict incipient failure in electric-power-system components. The development of continuous monitoring techniques to detect an incipient failure would represent a significant improvement in system maintainability, availability and safety, This report describes the analytical and experimental aspects of the project. Mathematical models have been developed to study the behavior of cables and motors which are undergoing a deterioration process. These models allow a detailed study of the effect of deterioration on the component's terminal characteristics and performance. The efficacy of using negative-sequence monitoring is a reliable indication of deterioration has been established. Techniques for assessing the sensitivity of the prediction algorithm to component deterioration have been presented. An approach for modelling electrically-excited vibrations, and including these in the algorithm, has been presented.

Jan 1, 1987

By Albert W. Deurbrouck

This Bureau of Mines report describes the washability characteristics of 13 coalbed samples collected in Colorado. Such data are needed to evaluate the quality of the coals of the West, where most of our low-sulfur-content coal reserves are found. Of the 13 samples included in this report, 11 had a total sulfur content of 1 percent or less. All of the samples contained low percentages of ash or could be readily washed to a desirable ash level with minimal loss of yield. The coals ranged in rank from high-volatile A bituminous to subbituminous B; nine of the samples were high-volatile C bituminous. The coalbeds ranged in thickness from 6 to 26 feet; the average was about 8 feet.

Jan 1, 1970

By L. A. Haas

The Bureau of Mines conducted bench-scale leaching tests with recycled spent copper electrolytes and copper-nickel mattes produced from the Minnesota Duluth Complex concentrates. This report describes the first stage of an overall two-stage leach operation. The objective of this research was to determine the matte-leach technology required to convert spent copper electrolyte into an enriched nickel liquor suitable for a nickel refinery and there-fore essentially free of copper, iron, and sulfuric acid. The experimental variables investigated were matte composition, particle size, spent electrolyte content, pulp concentration, oxygenation, temperature, and time. The time required to produce an enriched purified nickel liquor decreased with increasing pulp concentration, temperature, and oxygenation, but increased with increasing particle size and electrolyte copper and acid content. Nickel-rich (about 50 g/l) liquors at a pH of about 4 and containing less than 1 g/l of copper and iron were produced at 70° C by leaching minus 325-mesh low-iron (less than 5 pct) matte for 8 hours with spent electrolyte containing 22.4 g/l Cu, 28.9 g/l Ni, less than 0.1 g/l Fe, and 50 g/l H2S04 at a pulp concentration of 1 kg of matte per liter of spent electrolyteo Varying the nickel content of the spent electrolyte from 11 to 101 g/l appeared to have no appreciable influence on the matte leaching characteristics.

Jan 1, 1981

By E. P. Ferrero

Analyses of 38 crude oil samples from 25 fields in Algeria, Libya, and Nigeria are presented in this report. The 38 crude oils are listed alphabetically by country and field. Also shown are the geographic and geologic sources of the samples analyzed, the companies that supplied the samples, the general characteristics and analytical and computed data, and the production for the fields from which the samples were obtained.

Jan 1, 1966

By E. P. Ferrero

Analyses of 38 crude oil samples from 25 fields in Algeria, Libya, and Nigeria are presented in this report. The 38 crude oils are listed alphabetically by country and field. Also shown are the geographic and geologic sources of the samples analyzed, the companies that supplied the samples, the general characteristics and analytical and computed data, and the production for the fields from which the samples were obtained.

Jan 1, 1966

By CHARLES L. WRIGHT

Coals may be divided into six classes-anthracite, semi anthracite, semibituminous, bituminous, subbituminous, and lignite. The first three cla~ can be distinguished by dHferences of composition, particularly the proportions of fixed carbon and the ratios of the fixed carbon to the volatile matter in the cools. The last three classes can be distinguished by di:fferences in physical character, chiefly in color and in manner of weathering. Lignite is brown, not black, and has generally a woody look, but it weathers in much the same way as subbituminous coals. On exposure to the air lignite slacks or crumbles. The lumps check and fall into small irregular pieces that exhibit a decided tendency to separate into extremely thin plates. Hence lignite deteriorates greatly during storage or long transportation. The most characteristic feature of the composition of lignite is a large percentage of moisture. '!his high moisture content reduces the fuel value of freshly mined lignite, and the partial evaporation of moisture, on expooure, causes th6 fuel to check and fall to pieces. Consequently, attempts to increase the efficiency of lignite as a fuel involve reducing its percentage of moisture and increasing its ability to endure storage and transportation. Both these results are accomplished by briquetting.

Jan 1, 1911

By E. R. Maize

[?he scconG rcport of :his st?rI.org 8cdt with o3servatioi:s of conver- gence of roof an4 floor at t!x*re: ?.cc.-.tioris iri til~ ClVucible mine of kke Cru- cib1.o Fuel Co. Data on sl:'ociacnce ?.rd Lztcrcl mwe:~cnt cf the surface were .:lven for two of these areas, cnS it was mentioned that ~lr~~ilar data were being obtained on a ?art of Pe:sc:rlvtzr.ia Fii~l?trr.y FE:, ~i!lic;l pcser: over the third area. 'I'hie hichwc :LEO FasseE over t!lc ITenncoli::. :.line of the Bnckeye Coal Co. 9 milcs to ';he so-lth, cnd at P. l~tcr C'..att: ~.nr?r.,cc?r:cntS *.rere mnd.e to make similar observati on3 there. This y: pr mrnmri:.c n Czto obtnino? at those two locetionn,]

Jan 1, 1941

By Charles L. Kusik

A study was conducted for the Bureau of Mines, U.S. Department of the Interior, to provide information which will lead to an increase in the recycling of mineral materials, in order to help conserve the Nation's mineral resources. Data were collected on energy requirements to recycle prompt industrial and obsolete scrap for nine metal commodities: Iron and steel, aluminum, copper, zinc, lead, stainless steel, titanium, tin, and nickel and nickel alloys. Major process routes for recycling were considered, starting from the first collection point through scrap preparation, transportation, smelting and/or refining to the molten metal, ingot, or other semi- finished form approximately equivalent to a primary metal of a similar composition. Available data for 1976 were collected on the amounts of each metal commodity recycled by major scrap categories. In addition, energy requirements were estimated for separating municipal solid wastes into four major categories: Refuse-derived fuel, and magnetic, aluminum, and glass cullet fractions. Finally, areas of research were identified to enhance recycling and/or increase the efficiency of energy use.

Jan 1, 1978

By John R. Bradley

The object of this paper is to survey and analyze the bearing of economic nationalism, competitive sources of energy, and technologic developments on international trade in coal with especial reference to the competitive position of the leading coal-exporting countries in the Italian market, the largest in the Mediterranean region, and the Brazilian market, the second largest in Latin America. The political, economic, and financial disturbances caused mainly by the World War have resulted in an amazing situation. Especially since 1930 have conditions been complicated.

Jan 1, 1936

By K. K. Kelley

The entropy values at 298.1° K. for the elements and inorganic compounds, on which sufficient data were available for calculation in 1931, were discussed in a previous publication (96).3 Since that time the specific beats at low' temperatures of many more inorganic substances have been determined, and considerable advances have been made in the realms of spectroscopy applicable to the determination of thermodynamic properties. Moreover, a critical study of the existing vapor-pressure data made by the author (98) furnishes entropy of vaporization results suitable for obtaining approximate values of the entropies of a number of gases from the entropies of the solids or liquids. Consequently, it appears worth while at the present time to supplement the former publication, giving the new values now obtainable and making such revision in the older values as the data warrant. The methods of calculating entropies were discussed in previous publications (96, 98) and will not be repeated here. ENTROPIES AT 298.1° K. FOR INORGANIC SUBSTANCES In the following pages, the same arrangement is followed as in the previous publication (96). All entropy values are expressed in 15° gram-calories per degree Kelvin per gram-formula mass of substance. The figures given for gases do not include the effect of nuclear spin, as is nearly universally customary at present. The estimates of accuracy in the case of the values obtained from heat-capacity data apply only to the existing measurements and to the necessary extrapolations as they are made. It is assumed usually that the substances are in such an energy condition at the lowest temperatures reached in the specific-heat measurements that the usual normal type of extrapolation may be made. No allowance is made for error in this assumption. The recent work on Gd2SO4. 8H2O and FeC13 illustrates the difficulties that may arise in obtaining the entropies of some paramagnetic substances. Also the data and calculations for such substances as CO, H20, and N20 show that the correct entropy is not obtained in all cases by indiscriminate application of the usual

Jan 1, 1936

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 Gerald L. Finlinger

This Bureau of Mines publication reviews underground methane drainage programs being conducted in various coalbeds. Equipment used in drainage programs such as drills, underground pipelines, and methane monitoring systems is described.

Jan 1, 1980