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By W. H. Ode

Low-temperature distillation tests at 200°, 350°, and 500° C. were made on a subbituminous coal from Boulder County, Colo., and a subbituminous coal from Weld County, Colo., in connection with a survey of carbonizing properties of American coals4/ and. investigations of their chemical and physical properties.5/ The coal represented by the sample from weld County was reported to give off combustible volatile matter at unusually low temperatures when placed on a fuel bed. The yields of tar and oil and the composition of the gas from this coal, as obtained in the distillation tests, did not confirm this report. These yields and the gas composition of the Weld County coal differed but little from those obtained from the coal from Boulder County. Both coals yielded tar and gas in amounts considered to be normal for coals of their rank.

Jan 1, 1937

By James P. Rider, Jeanne A. Zimmer, Andrew B. Cecala, Robert J. Timko, Earle H. Andrews

Many different types of structures and materials have been used to build mineral processing facilities over the past few decades. Although the structure type and building material were not viewed as significant factors affecting the health of employees in these facilities when they were built, the National Institute for Occupational Safety and Health performed an evaluation to determine to what extent building types could impact respirable dust and noise levels. This report discusses the evaluation of three different types of product sizing silica sand structures: a masonry design, a steel-sided design, and an open structure design. The data obtained in this study indicate that the open structure design (no walls) was superior from both a dust and noise (health) standpoint compared to the other two structures. The open structure design should also be beneficial from a cost standpoint because of lower material and construction costs. Companies and design engineers should consider this open design when building new mineral processing facilities in climates where it could be applicable. Some companies may also want to consider modifying existing structures with a more open design to further reduce dust and noise levels. As the trend continues in lowering allowable dust levels for federal health standards in the U.S. mining industry, the open structure design may be an approach for some companies to consider for their operations.

Jan 11, 2006

To evaluate the effectiveness of dust collector bags for reducing dust liberation from a roof bolter dust collection system.

Jan 2, 2007

By Maria I. De Rosa

This report analyzes mine fires for all U.S. underground and surface coal mining categories by state and 2-year time periods during 1990-1999. Risk rate values are derived, and ignition source, methods of fire detection and suppression, and other variables are examined. The data were derived from Mine Safety and Health Administration (MSHA) mine fire accident publications and verbal communications with mine personnel. The analysis will provide the National Institute for Occupational Safety and Health, MSHA, and the mining industry with a better understanding of the causes and hazards associated with mine fires and will form a basis for future fire research programs.

Jan 1, 2004

By H. W. Lang

The Bureau of Mines conducted an investigation to observe the effect of cetane improvers upon nitrogen oxides concentration in diesel exhaust gas. Amyl nitrite and amyl nitrate were used as additives to the fuel used in a four-cycle, single cylinder type test engine. It was concluded that nitrogen oxide concentrations were not enhanced at fuel-air ratios above 0.03 pound of fuel per pound of air.

Jan 1, 1969

By D. E. Wolfson

The Bureau of Mines investigated the use of preheated coal in carbonization operations. Liquor yields and coking times were reduced, coke quality was improved, and smokeless pipeline charging to coke ovens should eliminate a serious source of pollution.

Jan 1, 1972

By Gerrit V. R. Goodman, Charles D. Taylor, Edward D. Thimons, Jay F. Colinet

The importance of controlling respirable dust and methane gas levels in underground coal mining cannot be underestimated. While respirable dust can significantly affect the occupational health of underground coal miners, methane gas accumulations pose significant safety concerns for these same workers. Water sprays and machine mounted dust scrubbers offer effective control of respirable dust exposures and methane gas accumulations. Water must not only be applied carefully to avoid dust rollback to the machine operator but must create sufficient turbulence to remove dead zones that could contain high concentrations of methane gas. While the flooded-bed dust scrubber has been generally responsible for decreased worker exposures to respirable dusts, this device has proved effective in controlling methane levels at the face. This paper reviews practical applications of water sprays and dust scrubbers to control respirable dust and methane gas on continuous miner faces.

Jan 4, 2000

By J. N. Tomlinson

Trailing-cable splices are evaluated for moisture exclusion abilities after repeated travel over shuttle-car sheave wheels. Tests are conducted on cables with jackets made of neoprene, cholrosulphonated polyethylene (CSPE), and nitrile butadiene-polyvinyl chloride (NBR-PVC) to 50° C. The results show that some splice kits are effective as received, others are improved with minor but significant changes, and still others must be redesigned to be effective in underground applications. Laboratory results are compared with actual underground splice results. Recommendations for cable preparation prior to splicing are presented.

Jan 1, 1979

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

MINE VENTILATION NETWORK ANALYSIS

Jan 1, 1977

By E. J. Kloos

Two self-contained breathing apparatus of the closed-circuit compressed-oxygen type were evaluated for performance at 32° to -25° F. Low-temperature effects of oxygen and carbon dioxide concentration, visual properties of the facepiece, and mechanical operation of the apparatus were studied. Although operation varied with the wearer, his breathing rate, the apparatus precooling time, and the temperature, results suggest that general use of currently approved compressed-oxygen closed-circuit breathing apparatus be limited to temperatures above 32° F.

Jan 1, 1968

Develop a new method for coal mint pillar stability evaluation and design based on pillar load measurements. Approach A novel approach to chain pillar stability evaluation and design for longwall coal mining panels has been developed by the Bureau of Mines. The evaluation approach uses an INTEGRITY FACTOR as the criterion for stability. Hydraulic borehole pressure cells developed by the Bureau are used to measure stresses in a pillar for stability evaluation. The results are used to improve the pillar design.

Jan 1, 1989

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

B 4 Description of Subroutines There are thirteen subroutines in the program: PROGIO HOIST MINER SMOKE STENCH MSMOK

Jan 1, 1976

By R. W. Dalzell, Fred N. Kissell, J. L. Banfield, M. G. Zabetakis

Methane concentration peaks were measured by the Bureau of Mines at coal mine working faces during entry development. The statistical distribution of peaks was found to be normal or log normal depending on how well the methane was being mixed into the ventilation airstream. A normal distribution indicated good mixing, whereas a log-normal distribution indicated that mixing was poor. In addition, the "highest" peaks over selected intervals were found to fit a type I extreme-value distribution, a result similar to that obtained while mining longwall faces.

Jan 1, 1974

By T. O. Llewellyn

Laboratory batch and semicontinuous studies showed the feasibility of using methylene bromide and trichloroethylene in heavy liquid cyclone concentration of a Nevada brucite ore. Cyclone tests of minus 20- plus 200-mesh material at specific gravities of 2.42 and 2.44 recovered 71.6 to 74.9 percent of the MgO at grades of 95.5 and 95.4, respectively. Neither increasing the feed pulp density from 5 to 25 percent solids, nor varying feed pressures from 25 to 60 psig had any apparent effect on the heavy liquid separation.

Jan 1, 1971

By G. B. Atkinson

Properties of catalysts prepared from intermetallic compound precursors were investigated by the Bureau of Mines as part of its mission to decrease U.S. dependence on foreign sources for scarce catalytic materials, such as nickel, cobalt, and chromium. Methods were developed whereby catalysts with surface areas of 30 to 40 m2/g were prepared from intermetallic compounds. Activity of these catalysts for the methanation reaction and methanol synthesis was deter-mined using a fixed-bed, single-pass, flow-through reactor. Catalysts prepared from rare-earth-nickel intermetallics had specific activity for methanation that was five times greater than that of commercial catalysts and were equal to or better than commercial catalysts with regard to sulfur tolerance. Under identical reaction conditions, catalysts prepared from thorium-copper intermetallics produced more than 10 times as much methanol as a commercial low-pressure catalyst and exhibited a high degree of catalytic stability.

Jan 1, 1982

By John C. Machisak

THIS CHAPTER of the Minerals Yearbook (Volume III) contains overall employment and injury experience for coal mines-bituminous, lignite, and anthracite; coke, petroleum and natural gas; and peat and slag plants; metal and nonmetal mines; sand and gravel operations; stone quarries; metallurgical plants, including metal mills and smelters; and nonmetal mills for 1959. Volume I of the yearbook contains injury experience and employment data in the metal, non-metal, sand and gravel, slag, and quarrying industries, and the milling operations and related plants. Volume II contains the injury experience and employment data in the fuel industries--coal, coke, petroleum and natural gas, and peat. Surveys conducted by the Bureau of Mines were the source of injury and employment data used to compile the tables and furnish information for the accompanying text. Response to the surveys was voluntary except that for coal mines. The Coal Mine Safety Act requires operators of coal mines to furnish the information requested.

Jan 1, 1960

By Judith A. Eisele

The possibility of improving the volatilization of gold through the formation of a metal-gold chloride vapor complex was investigated. Gold-silica mixtures, containing ferrous and nonferrous minerals and salts as additives, were treated in a laboratory tube furnace with a flow of chlorine gas at various temperatures. The addition of pyrite (FeS2) to a charge of gold-silica increased the volatility of the gold from 3, 20, and 62 percent of the total gold to 62, 93, and 100 percent at 200°, 300°, and 400° C, respectively. Chemical analyses of the condensate indicated the volatile species to be FeAuCl6.

Jan 1, 1971

By W. E. Anable

A 180° magnetic deflection residual gas analyzer mass spectrometer with a mass range of 2 to 200 amu was used to study the nature of gases evolved during arc and electron-beam melting of certain reactive and refractory metals. The partial pressure of residual gases over molten Mo, Hf, Ti, and Fe, was found to be similar: Water and hydrogen were evolved from the samples and from the furnace components, carbon dioxide and carbon monoxide resulted from deoxidation of some of the melts. Argon and acetone were residuals in the system, and methane was a decomposed organic compound from the oil diffusion pump.

Jan 1, 1969

Provide minx operators with means for evaluating dust generation and bit wear effects on Production without costly and extensive underground testing. Approach Develop personal-computer-based cutting system models that will simultaneously evaluate machine, Coal seam, and mine-operator-controlled parameters for their interactive effects on dust generation, bit wear, and Production by either a longwall shearer or a continuous miner. How It Works CSM Programs have been developed to analyze relative dust generated by a double-drum, ranging arm, longwall shearer and a continuous miner. These interactive programs Provide relative dust, culling forces, and production values for any given set of mining machine parameters, specific seam conditions, and operator-controllable parameters. Expanded versions of each program provide a dynamic evaluation of the effects of bit wear, over time, on production.

Jan 1, 1989

By C. M. Mason

A method for evaluating the relative incendivity of detonating cord in natural gas-air mixtures was developed. The method consisted of firing short lengths of cord in bundles to determine the number of strands per bundle which would ignite natural gas-air mixtures 50 percent of the time in the 45-cubic-foot gallery of the Bureau of Mines. The relative efficiency of a flame quenching agent, potassium acid tartrate (KHT), when incorporated in both the pentaerythritol tetranitrate (PETN) core and the polyethylene sheath, was explored. The effects of sheath thickness, sheath composition, core weight, and core composition were evaluated. The bundle method established a quantitative scale for evaluating the relative incendivity of cords. The relative incendivity determined by the bundle method was then compared with the incendivity of 100-foot lengths of detonating cord when initiated in 8 percent natural gas in the 640-cubic-foot gallery of the Bureau of Mines.

Jan 1, 1968