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By Dorsey A. Lyon

At the main experiment station of the U. S. Bureau of Mines , situated in Pittsburgh, Pa . , three phases of its work in behalf of the safety of the coal miner are the establishment of permissible explosives for use in gaseous and dusty mines , the development of electrical equipment that can be used with safety in mines of this character , and improvement in the safety of mechanical devices used in and about the mines . Also That these efforts are beginning to have a cumulative effect in lives. saved is evident from the fatality statistics of the industry . Although nearly 80,000 more men are employed in coal mining than ten years ago and much more coal is mined , the fatalities each year are considerably less than ten years ago . the amount of coal mined in a year for each life lost has risen between 60,000 and 70,000 tons . In 1909 , the year before the Bureau was created , the production of coal for each life lost was 174,416 tons . In 1920 , the production for each life lost was 285,000 tons .

Mar 1, 1921

By Raymond P. Maloney

The Rhyolite mercury prospect is on the south flank of Juninggulra Mountain--a large rhyolite intrusive in the Kuskokwim River region about 36 airline miles northwest of Red Devil, Alaska. Bulldozer trenching by the Bureau of Mines exposed bedrock at intervals in a 2,000-by 3,000-foot area where previous prospecting by the owners had disclosed abundant float and several in-place stringers containing cinnabar in widely varying amounts. The additional trenching indicated that the mercury mineralization in the limited area investigated was confined to erratically distributed short stringers and to small lenses, occurring in discontinuous zones in numerous silica-carbonate dikes and sills or along their altered contacts with sedimentary rocks. The geologic relationship of the mercury-bearing silica-carbonate dikes and the nearby rhyolite intrusive is similar to that existing at several other mercury mines and prospects in the. Kuskokwim region. The depth of over-burden and the presence of permafrost were serious obstacles to bulldozer trenching, and only a comparatively small part of the mineralized area was thus investigated.

Jan 1, 1962

By E. J. Gleim

Contact with trolley wire in the mines of the United States has taken a considerable toll of life throughout the years that trolley locomotives have been employed as a means of' transportation. A study3/ of the records over a 15-year period for one State alone showed that, of 98 fatalities resulting from contacts with electrical circuits and equipment, 75 were caused by direct or indirect contact with unguarded trolley wire in coal mines. The law relating to guarding trolley wires in the mines of this particular State, as amended in 1935, reads in part as follows: "All trolley wires carrying 220 volts or more, and less than six feet six inches above top of rail, must be guarded at all points under which men and animals are required to pass***,'" The natural conclusion to be drawn from such records is that lack' of guards or shields must be held responsible for these fatalities. As a preventive measure, it has been advocated that every foot of trolley wire in mines should be guarded. Although some such drastic steps may appear to be amply justified, closer examination of the records nor this and other coal-mining States shows that absence of guards is not entirely responsible; but rather that other factors, such as carelessness and neglect it the observance of certain well-established simple rules concerning installation and location of trolley wires, also are responsible. In other words, if trolley wire is installed carelessly and its maintenance is neglected, it should not be expected that the mere installation of guards will overcome such carelessness and neglect. This publication discusses Various types of guards that have been used in Coal and metal mines of this country, together with related steps bearing upon the problem of 'preventing shock and fatalities from contacts with trolley wire. The material herein contained is taken largely from Information Circular 6577,4/ now out of print, and has been revised to include some types of guards that have been used in metal mines, together with a discussion of guard materials not covered in that publication.

Jan 1, 1945

By G. W. Grove, G. L. FreAS

One of the chief hazards in mining bituminous coal is the accumulation of coal dust in the mines . When coal dust is thrown into suspension , it can be ignited and exploded by electricity through short -circuiting of mining machinery and trolley wires , or by arcs and sparks . The Bureau of Mines has endeavored to assist the coal -mining industry in preventing disasters from this cause by urging that all bituminous -coal mines be rock -dusted . As it has been difficult to convince some mining men of the danger of ignition of coal dust and of the effectiveness of rock dusting in preventing widespread explosions , a small , portable , coal -dust - explosion gallery has been designed to demonstrate the explosibility of bituminouscoal dust . Such galleries are furnished to Bureau engineers , inspectors , and safety instructors to illustrate visually and impressively the Bureau's accident -prevention educational work on the causes and prevention of dust explosions in bituminous -coal mines .

Jun 1, 1949

By Timothy J. Orr, Michael J. Beus, Frank T. Duda

The technology to enhance safety and control features for mine shaft hoists is being investigated by researchers at the U.S. Bureau of Mines (USBM). The objective of the research is to prevent injuries and fatalities related to hoist and elevator operations. Monitoring and controlling mine hoisting operations will allow hoist operators, inspectors, and maintenance personnel to increase their awareness of potentially dangerous situations and provide controls for safer operations. Process simulation and visualization software, real-time data sensing, and advanced programming techniques are being applied to this problem. Development of reliable and cost-effective sensors and data acquisition interfaces to monitor hoist loads and detect slack rope conditions is underway. Three-dimensional design software was used to visualize mine hoisting to enhance understanding of hoist operations. Quick Basic and Visual Basic (an object-oriented Windows interface) are being used for acquiring and processing hoisting data. Testing and evaluation of components are underway at USBM testing facilities. The resulting system will allow hoist personnel to assess critical operating parameters, such as hoist position, speed, acceleration, conveyance load, and rope tension.

By Thomas H. Dubaniewicz, Gerald R. Cucci, Gregory M. Green, Kenneth L. Cashdollar

New types of industrial instruments use fiber-coupled law energy to power remote serum. Fiber-optic based instruments are useful in classified (hazardous) locations found in many industrial plants because the fiber provides a natural barrier against accidental electrical discharge into potentially explosive atmospheres. However, current safety standards do not cover the use of laser-powered fiber-optic instruments in potentially explosive environments such as found in coal mines. The U. S. Bureau of Mines began an investigation of laser-powered fiber-optic instruments in explosive atmospheres in support of the standards-making process. A commercial fiber-optic interface system, modified to sin relate several worst-case operating conditions, ignited explosive hydrogen-air mixtures. Worst-am simulations consisted of disabling a safety shutoff feature, operating the laser at significantly higher powers than intended for normal operations, and cleaving fiber-optic connections to direct laser energy onto selected absorptive materials. At the highest power level available, the fiber-optic interface system did not ignite selected methane-air mixtures. The obtained data should prove useful in establishing appropriate safety standards.

By Robert J. Timko, R. Lincoln Derick

This U.S. Bureau of Mines study examined spontaneous heating episodes in coal mine pillars in an active underground coal mine. The information obtained from these incidents was then analyzed to learn which sampling methods provided the earliest indication of pillar heating. The objective of this study was to discover if the location of future events of pillar spontaneous heating could be inferred from the available information. The spontaneous heating-prone area in this evaluation involved pillars located just in by the mine portals. Several detection methods were used to determine gas levels outside as well as inside the affected pillars. It was hoped that, by incorporating external and internal sampling methods into an organized program, locations undergoing spontaneous heating could be determined more readily. This study found that by drilling small-diameter boreholes into the pillars, then obtaining gas samples from the affected pillars, the ability to locate early spontaneous heating episodes was improved. However, the ability to accurately predict future spontaneous heating events remains in question.

Jan 1, 1995

By Michael R. Grubbs

The Bureau of Mines is currently developing methods for reclaiming the metal and mineral values contained in unburned urban refuse. One important phase of this research deals with recovering Mastic from shredded refuse using in electrodynamic separation process. The results of this study have indicated that mixed plastic concentrates analyzing 99.4 percent plastic can be consistently recovered from the light material fraction of shredded refuse, leaving a mixed paper traction analyzing 99.9 percent paper. Recovery of the plastic exceeds 99 percent.

Jan 1, 1972

By W. D. Walker

All pipelines used to transport liquid fuels over coal mines are potentially hazardous; however, this publication deals only with dangers in transporting gasoline. Since transporting gasoline by this method is an established practice, the hazards connected therewith should he recognized by coal-mine operators and pipeline companies so that every known precaution may be used to reduce and keep the hazards to a minimum. The purpose of this paper is to direct the attention of coal-mine operators and employees, pipeline-company officials, and other interested persons to the explosion and fire hazards that arise from seepage of gasoline into underground mines. A hazard is not only presented in an individual mine when gasoline enters underground workings; but, in cases where mines are interconnected, a hazard exists in mach such mine.

Jan 1, 1954

By L. C. IlsLey

From time to time the Bureau of Mines has issued publications dealing with the various classes of explosion-proof mining machinery that have been tested and approved as permissible for use in mines having atmospheres that may become inflammable by reason of the inadvertent presence of gas or dust. These publications are confined almost entirely to description of the features contributing directly or indirectly to the prevention of explosion or shock hazards, and are intended to give inspectors, safety engineers, and others already familiar with the general safety requirements more detailed information on the safety features of the design of a particular machine. As a background for papers describing permissible machines and to avoid the necessity of duplicating descriptions of methods of conducting investigations and tests of such machinery, Bureau of Mines Bulletin 305, Inspection and Testing of Mine-Type Electrical Equipment for Permissibility, was published in 1929. Three bulletins giving detailed descriptions of the three most numerous types of machines have been issued, viz., Bulletin 313, Permissible Storage-Battery Locomotive and power Trucks. Bulletin 343, Permissible Coal-Handling Equipment. Bulletin 382, Permissible Coal-Cutting Equipment.

Jan 1, 1937

By David S. Yantek, Paul Jurovcik, Eric R. Bauer

Workers in coal preparation plants, where vibrating screens are significant noise sources, are often exposed to sound levels exceeding 90 dB(A). The National Institute for Occupational Safety and Health, a major coal company, and a vibrating screen manufacturer conducted a cooperative study of vibrating screen noise. Rubber isolators reduced sound levels by 1 dB. Urethane screen panels did not reduce sound levels in this case. Drive noise was determined to be the dominant noise source on the screen. Damped side plates reduced vibration levels on the screen sides by 1 to 7 dB(A). Detailed results of the study are presented.

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 Alfred E. Schwaneke

The surface tension from 240° to 844° C and the density from 236° to 583° C of 99.999 percent purity liquid tin has been measured using the maximum-bubble-pressure method. Results for surface tension (y) show y (dynes/em) = 566.84 -4.76 X 10-2 T (° C) with a standard error of 1.9 dynes/cm. Results for density (p) show p (g/cm3) = 7.16 -6.3 X 10-4 T (° C) with a standard error of 0.012 g/cm3. Comparisons with other data found in the literature are discussed. The experimental results are considered to be as good as any data presently available.

Jan 1, 1970

Underground and strip mining (6,7) produce different hydrologic environments. Many underground mines are below the zone that is completely saturated with water and the mine openings may cause new and continuous contact between sulfurous material and water which flows from the saturated zone to the workings. Strip mines are usually above the zone of continuous saturation and contact between sulfurous material and water is generally restricted to periods of precipitation. A full appreciation of the problem of water pollution caused by drainage from deep mines requires a basic understanding of occurrences and movement of water in the ground and the modes of ground water entrance into mining areas.

Jan 1, 1970

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 D. A. Wilson

A process was developed on a laboratory scale in which a solid waste byproduct from refining of secondary lead was converted into three valuable products. Roasted lead blast furnace matte was leached with water to recover copper. This was followed by brine leaching to recover lead. Residues were finally smelted to yield pig iron. Copper was precipitated as cement copper and the lead product obtained was a mixture of pure 3PbO.PbC12.xH20 and Pb(OH)C1. Copper recovery was 89 percent and lead recovery was 96 percent.

Jan 1, 1967

By Isaac A. Zlochower

This paper presents data on the limiting (minimum) oxygen concentration (LOC), in the presence of added N2, of methane (CH4), propane (C3H8), ethylene (C2H4), carbon monoxide (CO), and hydrogen (H2), and some of their binary mixtures. It also addresses the issue of the flammable concentration (flammability) limits of these pure gases in air. The study is based on spark ignited explosions in large, spherical laboratory vessels (120-L and 20-L) using a 7% pressure-rise criterion for explosion propagation. The results of the study are compared with the older values which used long flammability tubes with a diameter >5 cm together with visual evidence of substantial upward propagation. They are also compared to results reported recently using a 12-L spherical flask with a visual flame propagation criterion. Finally, they are compared to results reported in Europe using more modest flammability criteria and smaller chambers. The findings reported here show excellent agreement between the 120-L and 12-L results, good agreement with the 20-L results, and reasonable agreement with the earlier flammability tube values for the lower flammability limits. They disagree, however, with the more conservative European values. These results and those from the 12-L experiments also feature lower LOCs than are given by traditional flammability tubes. A model for the LOCs of such fuel mixtures based on the Le Chatelier mixture rule for lower flammable limits is seen to reasonably fit the observed results on binary mixtures and can accommodate more complex mixtures as well. One such set of ternary mixtures containing CH4 and 1:1 CO:H2 is well fitted by the model.

Jan 1, 2009

By H. C. Ko

As part of the Federal Bureau of Mines effort to provide thermodynamic data for the advancement of minerals technology, energy conservation, and environmental preservation, the standard enthalpies of formation of a-magnesium sulfate, a-magnesium sulfate, and magnesium sulfate monohydrate were determined by hydrochloric acid solution calorimetry. The values of the standard enthalpies of formation in kcal per mole at 298.15 K are -307.95 ± 0.13 for a-MgS04, -307.03 ± 0.13 for ß-MgS04, and -384.72 ± 0.13 for MgS04 .H2O.

Jan 1, 1979

By M. J. Ferrante

Relative enthalpies of V20S from 298.15 to 1,101.0 K were measured at the Bureau of Mines to provide data needed for the advancement of min-eral technology. Enthalpies were measured with a copper-block calorimeter. A sharp melting point was found at 951 K, with [~~ = 15.690 kcal/ mol ] for the standard enthalpy of melting. Tabulated values are given at selected temperature increments between 298.15 and 1,500 K for the standard relative enthalpy [(HO -H~98),] heat capacity (CpO), entropy (SO), and Gibbs energy function [-(Go -H298)/T]. Standard relative enthal-pies are also given in equation form and combined with data from the literature to derive values of standard enthalpies of formation and Gibbs energies of formation.

Jan 1, 1986

By Albert E. Schreck

THIS CHAPTER concerns such minor nonmetals as greensand, meerschaum, mineral wool, staurolite, and wollastonite. GREENSAND Output of greensand (glauconite) was slightly higher than in 1958. Open pits of The Kaylorite Corp. (Calvert County, Md.), National Soil Conservation, Inc. (Burlington County, N.J.), and Inversand Co." (Gloucester County, N.J.) accounted for the entire production. Soil conditioning used about 72 percent of the greensand sold. The remainder was used as a water-softening agent. Prices for greensand, f.o.b. mine, ranged from $13 to $70 per short ton.

Jan 1, 1960