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By Launa Mallett, Charles Vaught, Michael J. Brnich, R. Lincoln Derick

After thoroughly covering the health and safety training subjects required under Title 30, Part 48, of the Code of Federal Regulations (CFR), mine operators often find themselves with little or no time left in the class schedule for other important topics. This paper discusses a technique developed in partnership with RAG Twenty mile Coal Co., Oak Creek, CO, for incorporating employee participation at all levels in fire prevention and safe equipment operation training outside of traditional classrooms. The process involves development of training modules consisting of short, 5- to 7-minute videotapes coupled with toolbox talks that ground the content of the videos within the context of a miner’s workplace.

Jan 1, 2002

By R. Sainath, Wils L. Cooley

Continuous monitoring of ground bed resistance is essential to insure a low-resistance path for fault currents, lightning strokes, and electrostatic discharges. This paper explains the salient features of the continuous ground bed monitor and its applications. The importance of a low-resistance path to ground is highlighted. Sample readings obtained with the ground bed monitor are included, and typical applications of this instrument are illustrated. This effort was supported by the U.S. Department of Interior's Bureau of Mines under USBM grant G0144138.

Jan 1, 1979

By George J. Conroy

Techniques for locating trailing-cable faults are discussed, particularly those techniques suitable for use in underground coal mines, which have been the subjects of Bureau of Mines research. The discussion concerns precautions and suggestions for locating faults, rather than detailed descriptions of apparatus.

Jan 1, 1979

By W. L. Staker

Alternatives were developed to the conventional ammoniacal carbonate leaching-steam stripping procedure for recovering copper as an oxide from contaminated scrap metal. By entraining air bubbles in the leach solution, the copper dissolution rate was increased to 1.5 g/in2 of copper surface per hour, compared to 0.5 g/in2/hr produced by conventional agitation in stirred tanks. Using entrained nitrogen gas bubbles for agitation in conjunction with powdered sulfur not only resulted in rapid dissolution but also simultaneous precipitation of the copper from solution as a high-grade cuprous sulfide.

Jan 1, 1971

By R. W. Van Dolah

The feasibility of formulating cap-sensitive slurry explosives for use in underground mines with potentially flammable gas atmospheres was examined. Formulations containing aluminum metal as sensitizer and sodium chloride to reduce incendivity were prepared; some were cap-sensitive and had adequate air-gap. Flaked aluminum metal rather than the atomized type proved to be the more effective sensitizing agent of the formulations tested for incendivity in the large gallery of the Bureau of Mines, some were found to be suitably nonincendive.

Jan 1, 1968

By Richard L. Lewis

This is a discussion of the application of the zonal harmonic series to problems involving dipole sources in the vicinity of spherical boundaries. The application of a formal zonal-harmonic series solution to directly obtain numerical results involves two distinct problems: namely, the convergence of the series solution and the accurate calculation of the special functions involved in the series solution. Some interesting techniques will be introduced which help to improve the convergence properties of the series solution.

Jan 1, 1973

By Forrest T. Moyer

THIS CHAPTER of the Minerals Yearbook contains injury experience and related employment information for the coal-mining, coking, oil and gas, peat, and native asphalt industries in the United States for 1962. Injury experience is measured by the number of injuries sustained per million man-hours of exposure in each industry. No attempt has been made to combine these data and present rates reflecting the mineral-fuel industries because the hazards of the separate industries are not comparable. Tabulations showing the trend of injuries and employment for all mineral industries are presented in volume III of the Minerals Yearbook. COAL The injury-frequency rate for the coal-mining industry of the United States increased less than 2 percent, according to reports received by the Bureau of Mines. The number of fatal and nonfatal injuries per million man-hours in 1962 was 45.86, based on final data for anthracite mines and preliminary data for bituminous coal and lignite mines.

Jan 1, 1963

By J. E. Matta

The Bureau of Mines has developed a tracer gas method for measuring leak-age through permanent mine stoppings. In this method, a temporary brattice is erected in the same entry as the leaking permanent stopping. Leakage was evaluated from concentration measurements of a tracer gas introduced into the space between the stopping and brattice. Stopping leakages ranging from 15 cfm to 265 cfm were simulated in an underground coal mine. Leakage values determined by the new method were within 10 pct of the known values.

Jan 1, 1978

By Fred N. Kissell

In this report the importance of diffusion in controlling the emission of methane in mines is examined. An in-situ diffusion parameter is defined and calculated for a hypothetical unfractured lump of coal in the Pittsburgh and Pocahontas No. 3 coalbeds. The values obtained are similar to those obtained with lump coal in laboratory experiments.

Jan 1, 1972

By E. Morrice

The effect of the temperature of SmF3-LiF electrolyte on the electrolytic preparation of samarium-cobalt alloy by the consumable cathode technique was investigated. The temperatures of the cathode zone, alloy collection zone, and samarium oxide (Sm203) feed zone had to be controlled carefully to obtain a satisfactory samarium-cobalt alloy product. Any appreciable deviation from certain temperature values adversely affected yield and product quality.

Jan 1, 1971

By L. H. Adami

Heats of formation were obtained for four anhydrous crystalline sodium borates by hydrochloric acid solution calorimetry. The heats of formation at 298.15° K from the elements are NAB02, -233.2 ±0.6 kcal/mole; Na2B07, -786.4 ±1.0 kcal/mole; NaB305, -549.9 ±0.8 kcal/mole; and Na2B6013, -1,412.5 ±2.0 kcal/mole, The heats of formation from the constituent oxides are NaB02, -31.5 ±0.8 kcal/mole; Na2B407, -78.8 ±1.3 kcal/mole; NaB305, -44.1 ±0.8 kcal/mole; and Na2B8013, -96.7 ±1.5 kcal/mole.

Jan 1, 1968

By Ann G. Kim

Methane in coal constitutes a serious hazard in coal mining. Draining the methane in advance of mining can mitigate this hazard, conserve energy, and offer economic benefits. This Bureau of Mines report evaluates the Pittsburgh coalbed in Greene County, Pa., to determine if advance drainage is feasible. The gas content of virgin reserves in Greene County is estimated at 100 to 200 ft3/ton, a total of over 370 billion ft3 of gas in an area approximately 310 mi2. Because of the similarity to natural gas, drained coalbed gas could be recovered and added to pipeline supplies of natural gas. The value of conserved gas would offset the cost of drainage and extend energy resources.

Jan 1, 1975

By D. J. Bauer

Liquid-liquid extraction techniques were investigated by the Federal Bureau of Mines for the fractionation of rare-earth solutions. Separatory funnel work using tri-n-butyl phosphate (TBP) for extracting ceric nitrate from solutions containing sulfate ion resulted in almost complete extraction. Similar tests using primary amines for splitting trivalent rare-earth pairs and fractions gave promising results. The ceric nitrate extraction procedure was scaled-up by use of pressure-bubbler equipment, a series of spray towers for extraction, washing, and stripping. In this case only 84 percent ceric nitrate extraction efficiency was achieved. This work was done using dilute sulfuric acid for stripping.

Jan 1, 1960

By Roy L. Wilfong

Surface area measurements were conducted on cadmium sulfide powders following thermal treatments at temperatures up to 500° C and treatment times up to 1 week. Thermal treatments at temperatures up to 300° C produced no significant changes in the surface area of the powders even after 1 week of exposure. At 500° C some decomposition of the cadmium sulfide occurred.

Jan 1, 1970

By James C. Cawley

A summary is presented of existing leaky feeder communications systems currently in operation in North America. Background information pertaining to previous use of leaky feeder technology is discussed along with the survey methodology. A review of some pertinent facts concerning propagation in tunnels and specific reference to mine tunnel propagation is presented. A summary of the characteristics of each mine visited is presented in tabular form, and methods of procurement and maintenance are discussed. The role of user training in efficient system use is presented. Seven sites representing eight mines are included in the survey. Economic and technical topics are considered.

By Thomas O. Llewellyn

Laboratory semicontinuous and continuous heavy liquid cyclone separation pilot plant tests were made to determine the feasibility of producing a high-grade kyanite concentrate from a kyanite-quartz rock sample from Graves Mountain, Ga. Use of a three-stage heavy liquid cyclone circuit demonstrated that a 96.4-to 99.0-percent kyanite concentrate could be obtained with recoveries of 95.5 to 96.7 percent. The test work showed that by steam stripping with 6.9 tons of steam per ton of ore and two stages of detergent scrubbing the residual TBE content of kyanite cyclone products was 0.22 pound per ton of ore.

Jan 1, 1971

By James C. Ault, Walter W. Kaufman

This Bureau of Mines manual for design of surface mine haulage roads covers such aspects of haulage road design as road alignment (both vertical and horizontal), construction materials, cross slope, and drainage provisions. Traffic control and design of proper lane widths to promote safe vehicle movement are included, as are suggested criteria for road and vehicle maintenance and for runaway vehicle safety provisions. The aim of this publication is to provide those involved with surface mine haulage road design with a complete manual of recommended practices that, if implemented, will promote safer, more efficient haulage routes.

By W. F. Marshall

The Bureau of Mines conducted a series of experiments to determine the influence of exhaust rebreathing on emissions from various gasoline and diesel engines. Tests were conducted that simulated operation of engines in nonventilated spaces as well as in spaces with partially restricted ventilation. Results of these tests showed that exhaust rebreathing can have a marked effect on exhaust emissions and thus on the composition of the air in the working space. For the case of restricted ventilation, unacceptably high (greater than 50 ppm) levels of CO in the air of the working space resulted from exhaust rebreathing rates as low as 8 pct exhaust in the engine's intake. Operation in a nonventilated space resulted in highly critical CO levels (fatal in a few minutes) at times corresponding to 1 to 3 pounds of fuel consumed per 1,000 cu ft of space. Tests involving spaces of various sizes showed that volume of the air space [per se] is not important--the primary variable is fuel consumed per unit volume of air space.

Jan 1, 1973

By T. G. Carnahan

The Federal Bureau of Mines investigated, on a laboratory scale, a technique for recovery of silver from pregnant solutions generated in the hydro-metallurgical treatment of complex base-metal sulfide concentrates with oxidizing chloride media. This technique provides a means for recovery and simplified reduction of accessory silver to metal from chloride solutions. The method consists of adding NaI or KI to the solution to precipitate AgI, which is then contacted with Na2S to produce Ag2S and to regenerate the iodide salt solution. Silver recoveries range from 99 pct with 20 pct excess iodide precipitant, to 92 pct when the theoretical stoichiometric amount of precipitant is employed. The Ag2S product can be reduced to silver metal by contact with aluminum chips in NaOH solution followed by purification with conventional fire refining techniques.

Jan 1, 1980

By John C. Edwards

The Bureau of Mines developed a mathematical model to calculate the aerodynamically induced lifting of coal and rock dust from a composite deposition on a mine entry floor and the subsequent transport of the dust ahead of the propagating combustion zone of a coal dust explosion. For a series of experimental explosibility tests approximated by combustion zones that expand at a constant flame velocity, the mass fraction of airborne rock dust ahead of the flame front, as well as the mass fraction overtaken by the combustion zone, was calculated. A statistical analysis of the theoretical results demonstrated with a high level of confidence that the propagating and nonpropagating test samples belonged to sepa-rate populations. This analysis was further supported by an independent model of the average temperature over the combustion zone.

Jan 1, 1988