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By Albert W. Deurbrouck

Twelve samples from six Barbour County coal beds were analyzed for this report. The samples collected were generally high sulfur content coals, frequently exceeding 3 percent in the raw-coal sample. Many of them could not be upgraded to acceptable metallurgical standards even by rigorous preparation procedures. The production of coal in the county in 1963 amounted to almost 3 million tons of which 44 percent was mechanically cleaned.

Jan 1, 1965

By R. W. Stahl

One of the broad purposes of the Bureau of' Mines since its establishment has been conservation of mineral resources. As some of the coal beds approach depletion, especially those coals suitable for making metallurgical coke, more and more attention is being given to means of recovering a larger percentage of coal in place. The customary system of mining in the United States is by room and pillar, or some variation thereof, which leaves pillars of coal to support, the roof. In many operations, where the pillars are not systematically recovered, the loss of coal often amounts to 50 percent or more of the original deposit. In many instances in developing new mines, It is planned to recover chain and barrier pillars on retreat when the mine has reached established boundaries. Too often, however, mines are abandoned for some unforeseen reason before completion of mining without recovering any pillars. Usually, these pillars are lost forever. With this in mind, the Mining Division, Region VIII, of the Bureau; of Mines is encouraging mining by longwall methods. It is a generally known fact that almost all of the European coal is mined by longwall methods, which are conducive to a high percentage recovery of coal. A comparison between mining systems usually is on the basis of tons per man per shift. Unless all operating conditions are similar, such a comparison could be misleading. Generally, the output per man shift in European longwall mines is less than that obtained in room-and-pillar mining in the United States. In European mining, maximum recovery of coal is not only mandatory but it must be accomplished without major damage to surface by subsidence. These restrictions necessitate packing or stowing with consequential increases In manpower and decreases in output per man shift.

Jan 1, 1954

By Manuel Gomez

A computerized, interpolative mapping technique based on the moving average method was shown to be adequate to estimate the between-drill-hole values of coal-seam variables. The forecasting of the spatial distribution of coal properties along the seam was of three kinds: (1) Estimation of the variable of interest on a regional basis from widely spaced sample points, (2) prediction of coal properties for product control from closely spaced data, and (3) prediction of coal properties for specified benches, or layers of the coal seam, from closely spaced sample points. Estimates obtained with the computerized, interpolative mapping procedure were useful in the delineation of seam thickness, elevation, and overburden and in the estimation of sulfur and ash concentrations during the early phases of exploration. This grid interpolation technique was found adequate to adjust between-drill-hole values for trends resulting from the combined effect of several variables on a measured response. This information, coupled with statistical and geologic data that can be obtained in the exploration phase of mining, enlarges the information base available for coal-mine development planning, energy forecasts, and environmental control associated with fossil fuel power generation.

Jan 1, 1972

By David E. Emerson

An improved method and apparatus for determining the impurities in helium by preconcentration and subsequent analysis by mass spectrometry are described. Preconcentration of the impurities is accomplished by passing a known volume of helium, at slightly above atmospheric pressure, through a metal coil and trap assembly immersed in liquid helium. The concentrated impurities are then analyzed by mass spectrometry. This method can detect impurities in the range of 0.01 to 600 ppm with an accuracy of better than ±0.05 ppm at the 1-ppm level. One operator can analyze 15 samples in an 8-hour day.

Jan 1, 1970

By Jerry T. McLendon

The proper disposition of phosphatic clays has been the subject of research and debated for years by phosphate producers, State and Federal research agencies, regulatory authorities, and environmentalists. To date, no "universal" solution exists for the ultimate disposl of phosphatic clays. This Bureau of Mines report examines the state of conventional clay disposal technology and reviews the technical progress of innovative alternatives. Twenty impoundment sites were investigated by the Bureau of Mines using geotechnical methods and laboratory analysis of cored samples. In addition, quasi-static cone penetrometer soundings were conducted to define clay and/or sand-clay interfaces en masse. Samples of the top, middle, and bottom hole segments were obtained at each station for laboratory studies of clay densities, pore fluids, plasticity, and mineralogical properties. The results of this study support the continued use of initial clay settling impoundments but emphasize the need for "in-line" systems to reduce the initial volumes of plant-generated phosphatic clays. The effective use of sand tailings is also encouraged to promote further consolidation of clays via self-weight stressing, sand-clay admixtures, and/or surcharging sand caps.

Jan 1, 1984

By C. W. Owning

"The Bureau of Mines has repeatedly emphasized the necessity of completely ""rock-dusting all coal mines, except anthracite mines, in every part whether in damp or dry condition."" Every open accessible part of, the, mine without exception should be thoroughly rock-dusted, including parallel entries, air courses, trackless entries, crosscuts, and rooms to within at least 40 feet of every coal face. Very few mines have followed this recommendation and warning, with the result that there have been explosions not only in mines which have not used rock dust but also in so-called rock-dusted mines. Following a number of mine explosions it has been reported that the mine was rock-dusted,"" whereas it is probable that only some of the haulage roads had been given a hurried application of rock dust and in most instances not as much as 5 per cent of the mine was really rock-dusted. That is not rock-dusting.Some conscientious, well-meaning mining men have felt that rock-dusting of haulage roads would effectively stop an explosion; however, when shown, through widespread explosions in mines ""well rock-dusted"" according to the above method, that leaving large areas undusted, furnishes paths through which a violent explosion may travel, these mining men have realized the necessity of thorough rock-dusting and have adopted this explosion-prevention method.The Mather Collieries mine, Pickands, Mather and Co., operators, at Mather, Pa., was the first mine in Pennsylvania to receive, full credit for rock-dusting under the new 'stringent ruling of the Pennsylvania Compensation Rating Bureau, the provisions of which require that:"

Feb 1, 1931

By Scott A. Stebbins

During 1981, the U.S. Bureau of Mines and U.S. Geological Survey conducted a mineral resource survey of the 6,400 acre (15,800 ha) Lincoln Creek RARE II area (No. 5983) in the Toiyabe National Forest (fig. 1). Samples of outcrops and stream channels contained no significant amounts of economic minerals. A radioactive deposit in a pegmatite dike occurs 1.25 mi (2.02 kin) southeast of the study area, hut similiar deposits have not been discovered within the area boundary. No coal or deposits were found.

Jan 1, 1982

By D. E. Anders

Saturated hydrocarbons from 60 selected samples of a 2,300-foot Green River Formation oil-shale core (Piceance Creek Basin, Colo.) were analyzed by gas-liquid chromatography techniques. Emphasis was placed upon the distribution of normal alkanes and 15 key-branched and cyclic alkanes. The latter compounds consisted of the C15, C16, C18, C19, and C20 chain isoprenoids, the 5-a and 5-ß C27, C28, and C29 steranes, three C30 pentacyclic triterpanes, and perhydro-ß-carotene. The results showed definite evidence of maturation of both the n-alkanes and the branched and cyclic alkanes; however, most if not all of the changes were limited to the indigenous soluble extract and were not the result of additional soluble extract generation from the insoluble kerogen. Source material and environmental variations were important factors in some of the observed differences in the branched plus cyclic alkane compositions.

Jan 1, 1973

By W. S. Sanner

Seven samples were analyzed from the major reserves of the Bottom Red Ash bed, Northern anthracite field. The data show variations in thickness and geo-logic structure and in the amount of coal that can be recovered. Recovery of market-grade (less than 17 percent ash) coal is high for all samples, ranging from 76 tp 95 percent in the 3-1/4-by 9/16-inch sizes. The occurrence of coal containing less than 5 percent ash varies from 19.5 to as much as 57.5 percent. Crushing the coarse sizes to minus 9/16 inch increased recovery of market-grade coal in six of seven bed samples. Crushing released sufficient impurities to cause substantial increases in yield of coal containing less than 5 percent ash for all samples. Analyses of the float coal indicate that the quality of coal is comparable for all samples.

Jan 1, 1967

By W. P. Yant

[At the majority of mines where flame safety lamps are used either as working lights or as a means of detecting gas, no check it made on this condition of the various parts of the lamp and their assembly other than a visual ink inspection. Although this inspection should be made carefully in view of tae serious consequence that may follow Vie use of a faulty lama, In many instances the inspection is of a perfunctory nature. The Bureau of Mines has therefore designed a small box or gallery for testing lamps for defects and improper assembly before they are taken into the mine. The test simulates the condition when a lamp is extinguished by its introduction into an explosive mixture and the operator attempts to relight the wick while the lamp contains the explosive mixture. This test is more rigorous than merely subjecting a lighted lamp to an explosive methane-air mixture. In the latter test the products of combustion tend to blanket the propagation of flame from within the lamp to the exterior, especially if there are defects at the top of the gauzes. Moreover, when the lighted lamp is subjected to an explosive methane-air mixture the methane builds up slowly within the lamp until the lower inflammable limit is attained, whereupon a feeble explosion occurs within. If the nonlighted lamps is first filled with the methane-air mixture that gives the maximum violence and is than ignited, the dampening effect of products of combustion is obviated and the strain on defects is]

Jan 1, 1930

By Lawrence Y. Marks

During the mineral survey of the Bob Marshall Wilderness and study areas by the author in 1971, 1973, 1974, and 1976 (Marks, 1978), the area designated Reservoir-North (RARE II No. H1-485) in January, 1979, (U.S. Forest Service, 1979) was examined, along with other lands adjacent to the earlier study areas. However, the 1978 open-file report covered only areas originally designated for study. The present report on Reservoir-North is based on earlier work. No work has been done in the area since 1976. Mineral Appraisal Reservoir-North RARE II area (No. H1-485) is in the Northern Disturbed Belt which has been identified as having high potential for natural gas accumulations and lesser potential for oil accumulations (Mudge, 1978). Oil and gas lease applications in the area, indicate interest by oil companies.

Jan 1, 1981

By R. E. Head

[Surveys of the manganese situation conducted by the Geological Survey any other agencies have definitely established the, fact that the tonnage of high-grade manganese or in the United States is relatively small. It is therefore obvious that large-scale production of manganese is possible only through beneficiation of low-grade material. Deposits of low-grade manganese ore are being examined by engineers of the Mining Division of the Bureau of Mines to determine their size and possibilities as sources of manganese on a tonnage basis. The Metallurgical Division of the Bureau is developing and perfecting beneficiation processes with the objective of utilizing such low-grade ores. Microscopic study of these ores represents one phase of the research.]

Jan 1, 1941

By R. E. Head

[Surveys of the manganese situation conducted by the Geological Survey and other agencies have distinctly established the fact that the tonnage of high- grade manganese ore in the United States is relatively small. It is therefore obvious that large-scale production of manganese is possible only through beneficiation of low-grade material. ]

Jan 1, 1941

By Fred N. Kissell

Methane flows and pressures were measured in mines in the Pittsburgh, Hartshorne, and Pocahontas No. 3 coalbeds. From the data, the permeability of each of these coalbeds was computed. It was found to depend strongly on the type of coal and on the amount of water in the coalbed, and it was found to increase with time. All of the coalbeds had a high-permeability zone adjacent to the face or rib, and the Pittsburgh bed exhibited directional anisotropy. Surprisingly, little or no overburden effect was observed.

Jan 1, 1972

By Albert L. Brautigam, Michael C. Leigh, August J. Kwitowski

The U.S. Bureau of Mines developed and tested a teleoperating system to control a new highwall mining system. A remote operator was provided out-of-sight sensory information and control of coal extraction and haulage equipment. Surface and production testing proved that the teleoperating system supplied the operator with sufficient sensory information to operate the mining system. Details on the teleoperating system provided in this report include (1) sensor selection, (2) a description of the electronic control system, (3) equipment selection and modifications, (4) the positive test results, and (5) recommendations for system improvements.

Jan 1, 1992

By Stuart Lipoff, John E. Trombly, Paul Brien, O&apos

System objectives and design criteria for an in-mine ULF radio paging system are discussed. Coding formats, frequency and bandwidth selection criteria leading to the system design are discussed. The prototype call alert transmitter and pocket page receiver is functionally described. The report includes circuit descriptions, schematics, parts lists, printed circuit fabrication and assembly drawings. The report concludes with an estimate of the manufacturing cost for each assembly.

By John A. Organiscak

Enclosed cabs are a primary means of reducing equipment operators? silica dust exposure at surface mines. The National Institute for Occupational Safety and Health experimentally investigated various factor effects on cab air filtration system performance. The factors investi­gated were intake filter efficiency, intake air leakage, intake filter loading (filter flow resistance), recirculation filter use, and wind effects on cab particulate penetration. Adding an intake pressurizer fan to the filtration system was also investigated. Results indicate that intake filter efficiency and recirculation filter use were the two most influential factors on cab penetration performance. Use of the recirculation filter reduced cab penetration by usually an order of magnitude over the intake air filter alone because of the multi­plicative filtration of the cab interior air. Intake air leakage and filter loading affected the cab penetration to a lesser extent, while wind had the least impact on cab penetration between the calm and 10-mph wind velocities tested. Adding an intake pressurizer fan notably increased intake airflow and cab pressure with only minor changes to cab penetration. A mathematical model was developed that describes cab penetration in terms of intake filter efficiency, intake air quantity, intake air leakage, recirculation filter efficiency, recirculation filter quantity, and wind penetration.

Jan 1, 2008

By John A. Organiscak

Enclosed cabs are a primary means of reducing equipment operators? silica dust exposure at surface mines. The National Institute for Occupational Safety and Health experimentally investigated various factor effects on cab air filtration system performance. The factors investi­gated were intake filter efficiency, intake air leakage, intake filter loading (filter flow resistance), recirculation filter use, and wind effects on cab particulate penetration. Adding an intake pressurizer fan to the filtration system was also investigated. Results indicate that intake filter efficiency and recirculation filter use were the two most influential factors on cab penetration performance. Use of the recirculation filter reduced cab penetration by usually an order of magnitude over the intake air filter alone because of the multi­plicative filtration of the cab interior air. Intake air leakage and filter loading affected the cab penetration to a lesser extent, while wind had the least impact on cab penetration between the calm and 10-mph wind velocities tested. Adding an intake pressurizer fan notably increased intake airflow and cab pressure with only minor changes to cab penetration. A mathematical model was developed that describes cab penetration in terms of intake filter efficiency, intake air quantity, intake air leakage, recirculation filter efficiency, recirculation filter quantity, and wind penetration.

Nov 1, 2008

By G. W. Birge, D. E. Wolfson, J. H. Lynch

This report presents all available 900 ° C BM- AGA carbonization and related data for coals from the principal beds of the southwest Virginia field in a form which permits ready comparison of product yields and properties of coals and cokes . Thirty- one channel samples from Buchanan , Dickenson , Russell , Tazewell , and Wise Counties were carbonized at 900 ° C in an 18 - inch - diameter retort . Blending properties of 10 of the coals were studied , and expansion of most of the coals and blends was measured in the Bureau of Mines sole - heated oven . Ash Most of the samples were chemically suitable for metallurgical use in coking blends , and their coking properties generally were satisfactory . content exceeded 10 percent in only three samples , and none of the coals contained more than 1.5 percent sulfur . Dry , mineral - matter - free fixed - carbon content of the coals ranged from 62.1 to 77.5 percent . Expansion behavior varied widely , ranging from 16.8 percent expansion to 27.6 percent contraction .

Jan 1, 1964

By M. M. Jones

Natural brines are potential domestic resources of minerals. The brines of Searles Lake, CA, for example, contain an estimated one-fourth of our current reserve of tungsten. A key to Bureau of Mines research to recover this critical mineral is the ability to quantitatively measure concentrations of particular constituents in the large number of brine samples and process solutions produced under a multiplicity of test conditions. This paper describes procedures used to determine arsenic, boron, phosphorus, silicon, and tungsten in these solutions by simultaneous inductively coupled plasma spectrometry. A variable in-ternal standard method was used to compensate for tungsten interference on the other analytes in tungsten concentrates, and matching standards were used to determine tungsten in raw brine. Other solutions were analyzed using normal techniques. Analytes were determined down to 1 mg/L with an average precision of 2.5 pet relative standard deviation. Accuracy, estimated using synthetic solutions and by comparison with values obtained by other methods, averaged about 2.5 pet. The methods were rapid, required little sample preparation, and provided the needed sensitivity.

Jan 1, 1985