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To enhance safety and efficiency when moving large mining equipment under energized trolley lines, and to assist in compliance with Section 75.1003.2, 30 CFR. Approach A system was designed, using established technology, that permits a remotely located circuit breaker to be controlled from the cab of a mine locomotive moving large mining equipment under energized trolley lines. This control consists of setting the desired trip current, automatic or manual tripping, resetting, and voice communications between the locomotive and a remote Circuit breaker location. How It Works According to 75.1003.2, 30 CFR, whenever a piece of off-track equipment (such as a longwall chock or a continuous miner) is moved by rail under energized trolley or feeder lines, power for the locomotive that is moving the equipment must come from only one' circuit breaker. This circuit breaker must be adjusted to permit no more than one-half its rated short-circuit current to flow. The intent is to lessen the danger if an accident should occur, and if the equipment contacts the trolley line. Even so, the danger is great. This half setting can still represent many hundreds or even thousands of amperes, enough to endanger personnel, the equipment, or the mine. The Remote Control System reduces this danger substantially by giving the personnel associated with the move total control over the associated circuit breaker. The system as designed, is intended to be used with portable circuit breakers that are pulled on a small flat car by a mine jeep, and either precede or follow the equipment, depending on the direction of the power. This portable circuit breaker is equipped with a commercially available solid state overcurrent relay and associated shunt. This circuit breaker is connected via heavy duty clamps around an open trolley line tie breaker such that the current through the shunt is also the current in the trolley line. A receiver, interfaced with the overcurrent relay and shunt, completes the remote system.

Jan 1, 1981

By Dana Reinke, Launa Mallett

Interest in training evaluation in the mining industry was piqued with the promulgation of Title 30, Part 46, of the Code of Federal Regulations. Under Part 46.3, a training plan is considered to be approved if it contains certain information, including “The evaluation procedures used to determine the effectiveness of training.” The present paper is a broad overview of training evaluation and is intended to give trainers and decision-makers a framework for planning or assessing training evaluation strategies. It discusses questions to consider when starting an evaluation plan, Kirkpatrick’s model of evaluation categories, and various ways to collect data. It does not provide detailed instructions on how to develop evaluation methodologies, but reviews topics to consider when creating an evaluation plan. Training evaluation is a term that has many different meanings: assessing the quality of a course, effectiveness of materials used, teaching style of an instructor, or the comfort of a classroom. An evaluation can be done informally over lunch or with highly structured data-gathering tools. It can produce results that are useful to trainers, program administrators, corporate decision-makers, or no one. The key to a worthwhile evaluation is clearly defining why the evaluation is being conducted. Once the purpose is defined, planning the evaluation strategy can begin. For an evaluation to be effective, it should be incorporated into the development of the training activity itself. The training evaluation worksheet at the end of this paper can be used to guide evaluation planning.

Jan 1, 2002

By Wilbur I. Duvall

In a previous report, entitled A Gage and Recording Equipment for Measuring Dynamic Strain in Rock, a control circuit for a drum camera was described. The purpose of this control circuit was to provide a means for firing seismic caps, synchronizing the firing of the cap with the opening of the camera shutters and generating an electrical impulse at the instant of detonation. The operation of this circuit depended on the following two characteristics of seismic caps: (1) these caps contain a bridge, which breaks at the instant of detonation, and, the firing delay time of the cap is a function of the firing current. During the course of the Bureau's studies, considerable difficulty was experienced from "firing hash", i.e., spurious vibrations that appeared on the records at the time of detonation. The cause of most of this "firing hash" was traced to the intermittent grounding of the cap leads at the time of detonation. As the cap leads were still connected to the firing battery, the grounding of the leads permitted current to flow through the rock to the gage and to return to the firing battery through the shield on the gage cables. The intermittent flow of current along the cable shield produced potentials on the gage leads that were recorded as the "firing hash." To eliminate this difficulty, it is necessary to remove the firing voltage from the cap leads the instant the cap detonates. This report supplements the previous report and describes an improved circuit that can be used to fire seismic caps, remove the firing voltage from the cap leads the instant the cap fires, control the firing delay time in the cap, and generate reference signals at the time current starts flowing in the cap circuit and at the time the cap detonates. These reference signals can be used to determine the firing delay time of seismic caps and the time at which the seismic wave is generated by the explosion.

Jan 1, 1950

By E. J. Gleim

To make a thorough survey of a coal mine in order to eliminate hazards, the competent safety engineer must be familiar with mere than one branch of engineering. It is essential that he know the properties of mine gases and the methods of detecting them, as well as hew to prevent dangerous as accumulations. It is also essential that he understand the action of overlying strata when the coal is removed, and the proper methods of protection by timbering or other suitable means of support. He must know the value of protective clothing in reducing injuries and mast be informed as to the correct handling and use of explosives to avoid premature blasts, misfires, and ether failures in blasting practice. He must understand hew to operate locomotives and cutting, loading, and various other types of machines to be able to recommend effective safeguards for protecting the men who use them in addition to being informed as 'to these and many ether activities connected with the mining of coal, he must net overlook electrical engineering if he wishes to combat the fire, shook, and ignition hazards attendant upon the use of electrical machinery and circuits in and around the mine intelligently. There are many points relating to safely in the selection, maintenance, and use of electrical circuits and equipment that are perfectly obvious to the electrical engineer but perhaps are not se evident to those not trained in this particular branch of engineering. Engineers of the U.S. Bureau of Mines who have made a special laboratory study of electricity as related to safety in minus haw e also made inspections of electrical installations at a large number of bituminous mines. These inspections have revealed practices and conditions that not only do not contribute to safety but that add nothing to efficiency and economy in the operation of the mine.

Jan 1, 1936

By A. B. Hooker

Investigations at the Pittsburgh Experiment Station have shown that the satisfactory operation of aflame safety lamp depends not only upon proper design and assembly of the lamp but upon the kind of fuel used, and that much of the trouble experienced with permissible flame safety lamps at mines is due to the common use of motor gasolines, none of which is suitable in the present types of permissible flame safety laps. This report gives the results of a limited study to determine what satisfactory fuels are available, the specification limits of such fuels, and to suggest modifications of assembly and care of the lamps to improve performance with any satisfactory fuel.

Jan 1, 1938

By Edward F. Divers

The Bureau of Mines recently tested a sideboard device that is designed to act as an extension of conventional brattice, thus improving face ventilation of developing room-and-pillar-type coal mining. In these laboratory tests, an 8-foot-long rigid sideboard was mounted vertically along the left fender of a full-scale-model ripper-type continuous mining machine, rising to the mine roof to provide an air seal. It extended from the auger support frame pivot point outby along the fender. A novel water spray manifold was used to form an air seal between the sideboard and brattice. Tests showed improvement in face ventilation with the prototype device, and also demonstrated that water sprays can form an effective air seal over a fairly wide pressure range. Based on this preliminary study, subsequent improvements may make the sideboard concept much more effective, thus affording a simple, inexpensive technique to improve the effectiveness of face ventilation.

Jan 1, 1979

By Robert L. Lagace, N. Albert Moussa

The objective of this project was to perform a preliminary study to determine the desirability/practicality of burying the communication cables in underground mines in order to protect then from the effects of fires and explosions We conducted discussions with Government and industry specialists on the physics of mine fires and explosions, mine disaster fighting, rescue, and investigation activities, and on nine operations. In addition we examined published experimental work and selected detailed NSHA accident reports on fires and explosions in underground mines. We found the overall desirability /practicality of cable burial must be regarded at this time as highly questionable, because of its benefit limitations to special sceneries, its practical operational shortcomings, and the availability of alternative cable protection options.

Jan 2, 1982

Assure fail-safe stopping of a mining vehicle immediately following a loss of electric power. Approach A separate emergency brake system which actuates when electrical power is interrupted, was installed on several mining vehicles and tested in a long-term underground mining demonstration. How It Works Separate, spring-actuated brakes, which press against brake discs, are used to stop the vehicle following power failure. To allow norm al movement of the vehicle, hydraulic oil under pres? sure from the vehicle's hydraulic system is directed to a spring? loaded piston in each emergency brake housing. That pressure causes the piston to compress the spring and relieves the spring pressure against the puck, thereby allowing the brake disc to turn freely. See Figure 1 A. If the electrical power fails or if the machine is turned off, a valve in the hydraulic line to the emergency brakes opens. That valve, shown as ?Solenoid Valve (automatic)" in Figure 1, which is normally held closed by its electrical solenoid while the vehicle is electrically powered, is opened by the spring in the valve assembly. The pressure in the hydraulic line which is connected to the emergency brakes then drops to

Jan 1, 1978

Protect rescue workers fighting fires or mine personnel temporarily working in hot environments from heat stress. Approach A specially designed ice-cooled vest is worn while working in hot environments where cooling the mine air is not possible. How It Works The vest holds a total of 44 individual ice cells in packets that are firmly held near the wearer's skin. These ice cells remove heat from the wearer, reducing heat stress and increasing comfort. The locations of the ice cells and packets are shown in the diagram. The vest is constructed in three layers with the outer layer being aluminzed fiberglass cloth. Its aluminized surface reflects radiated heat, and its fiberglass cloth provides fire resistance and strength.

Jan 1, 1979

By R. W. Crocker, H. H. Clark

The purpose of the investigation discussed in this bulletin, one of a series dealing with the use of electricity in mines, was to study the various means and methods used to confine the flashes that occur when a switch carrying electric current is opened. The flash result- ing from the opening of a 250-volt direct-current circuit carrying more than half an ampere will ignite explosive mixtures of mine gas and air. An equally dangerous flash may be produced by even less cur- rent from a 500-volt circuit. Few mine electric circuits carry less than half an ampere when in use. The need of protecting the switches of such circuits in places where gas is likely to be present is therefore obvious. Two general methods have been proposed for preventing switching flashes from igniting gas surrounding the switch. One method is to inclose the switch in a casing provided with openings that are covered with wire gauze or otherwise designed and equipped for preventing the passage of flames from the interior to the exterior of the switch casing. Switches so protected are called explosion-proof switches. The second method is to immerse the switch contacts in oil to a depth sufficient to quench any flash that may occur when the switch is operated. Switches so protected are called oil switches. The success of the first method of protection depends upon the proper design and construction of the switch casing. It is essential to the successful operation of the second method that the switch contacts be surrounded by the proper kind of oil in good condition. There are several ways in which an oil switch may be deprived of its protective feature. The oil tank may not be filled or, if filled, the oil may leak out or be spilled. The oil tank may be removed (in some designs) and not replaced or through neglect the condition of the oil may become such that it is no longer an efficient protection. While such contingencies are not likely to occur, and although oil switches may be so designed that the loss of oil is not probable, nevertheless, as compared with oil switches, explosion-proof switches seem to

Jan 1, 1913

Dec 1, 2007

By R. Hogg, T. F. Dumm

"Procedures for particle size analysis on respirable dust from coal mines have been evaluated. Using respirable dusts dispersed in a laboratory dust chamber, size distributions measured using cascade impactors have been compared with the results of a variety of laboratory sizing methods performed on samples collected on filters placed side-by-side with the impactors. The laboratory techniques included centrifugal sedimentation, laser diffraction/scattering and automatic particle counting. The general agreement among the various methods was very good, with systematic differences which can be attributed to the different definitions of size used. Simple conversion factors have been obtained which can be used to transform the laboratory data to equivalent aerodynamic sizes.Similar comparisons have been made on samples collected in underground coal mines. Again, the results are in quite good agreement although small discrepancies were observed in· some cases. These have been attributed to some degree of agglomeration in the airborne dust, leading to slightly coarser apparent distributions in the impactor samples INTRODUCTIONA primary goal of mine ventilation is the control of airborne dust, especially in the ""respirable"" size range, typically defined as finer than about 5 to 10 µm. It follows that determination of the amount and characteristics of the respirable dust is an important factor in evaluating the performance of ventilation systems. Particle size information on airborne dust in mines is commonly obtained by in- situ measurements using cascade impactors. However, these tend to be inconvenient for routine data collection and the alternative approach of collecting samples in the mine, on filters for example, and returning them to the laboratory for detailed analysis is very attractive. Questions have often been raised, on the other hand, as to the appropriateness of this approach. How well · do such laboratory methods describe the distribution of aerodynamic diameter of the airborne dust particles in the mine environment? The purpose of the work described in this paper was to evaluate some laboratory sizing methods and to compare the results of such measurements with the size data obtained by the direct, in-situ method."

Jan 1, 1989

By H. W. Wainwright

One phase of the research and development work on synthetic liquid fuels conducted by the Bureau of Mines at Morgantown, W. Va. in cooperation with West Virginia University deals with the purification of synthesis gas.2/ Most of the experimental studies on gas purification have been directed toward the removal of organic sulfur from gas, either catalytically or by adsorption with activated carbon. An important part of the purification program has been the development of suitable analytical methods for determining organic sulfur compounds. As the total sulfur content, organic and inorganic, of purified synthesis gas should not exceed 0.1 grain per 100 cubic feet, the need for accurate analytical methods is apparent. It is also apparent that such methods must be rapid if one wishes to evaluate various processes for removing sulfur from gas. The organic sulfur found in most gas produced from coal is usually present as carbon disulfide, carbon oxysulfide, methyl and ethyl mercaptans, and thiophene, with the exception of thiophene, the remaining organic sulfur compounds respond similarly to catalytic treatment and can be removed effectively. Not only does thiophene resist most catalytic treatment, but it poisons some catalysts, rendering them ineffective in removing the other forms of organic sulfur.

Jan 1, 1950

By L. J. Prosser, A. T. Iannacchione

From 1991 through 1995, 44 miners out of a total workforce of less than 2,000 were fatally injured in the stone industry. Of these, 12 occurred at underground mining operations with nine deaths resulting from roof or rib falls. A safer environment can be achieved by evaluating the nature of the hazardous ground and by developing more efficient and effective ground-control strategies Roof and rib conditions were observed and assessed in 33 underground stone mines in Illinois, Indiana, Kentucky, Maryland, Missouri, Pennsylvania and West Virginia (Fig. 1). Hazard assessment indicated that the ground failures that occurred under moderate to substantial overburden. i.e., >30 at (100 ft), were caused by stress concentrations and geologic strictures. Ground failures near the surface are caused by solution (water) processes. Selection of the mining horizon and mine-layout decisions tremendously influence ground stability.

By L. D. Tracy

"This paper represents work conducted by the Bureau of Mines in cooperation with the Illinois Geological Survey and the Engineering Experiment Station of the University of Illinois.IntroductionThe present report covers conditions and mining royalties in District VIII of the coal fields of Illinois, as designated by the Illinois Geological Survey. The various districts have been described in the reports on the Illinois coal-mining investigations, carried on cooperatively by the Illinois Geological Survey, the engineering experiment station of the University of Illinois, and the U. S. Bureau of Mines. This district includes Vermilion and Edgar Counties, but as the coal-mining operations in Edgar County amounted to only 827 tons in 1923, the data here given have been confined to Vermilion County.A similar report on District VI (Williamson and Franklin Counties) has been issued as Serial 2722 of the Bureau of Minos.A description of geological and mining conditions, and a discussion of market and transportation facilities, have been included because these have an important bearing on the royalties specified and the general conditions of the lease.Mining ConditionsDistrict VIII is better known as the Danville district and in 1923 produced 4,177,000 tons of coal, or approximately L per cent of the total output for the entire State for that year, which was 79,300,000 tons."

Apr 1, 1926

By L. M. Demers, D. C. Kuhn

The alveolar macrophage (AM) responds to stimuli such as coal mine dust by releasing inflammatory mediators such as cytokines, growth factors. reactive oxygen species. and eicosanoids. Eicosanoids are synthesized by°AM through the action of cyclooxygenase and lipoxygenase enzymes and serve to modulate the proinflammatory function of this cell as part of the lungs' host defense mechanism. Reactive oxygen species can be generated by AM as a by-product in the biosynthetic pathway of the prostaglandins. AM produces primarily prostaglandin E2, thromboxane A2, and leukotriene B4 as part of the cellular response to an inflammatory stimulus. There is evidence to suggest that eicosanoid production by AM is functionally linked to both surface interaction with mine dust particles like silica and by the phagocytosis of the dust particle itself. In this report, we examined the effects of an antioxidant, vitamin E. on dust-induced synthesis of PGE2 and TXB2 in vitro and in vivo by AM obtained by bronchoalveolar lavage from rats. We also looked at the effects of the surface of silica particles on AM eicosanoid biosynthesis under conditions of calcination, a process that removes exposed hydroxyl groups from the surface of silica particles, thus reducing the likelihood of soluble hydroxyl radical formation. Treatment of AM with vitamin E in vivo and in vitro reduced the augmentation in eicosanoid production usually observed when AM are exposed to mine dusts. These results suggest that vitamin E may effectively reduce the inflammatory and fibrotic response produced by inhalation of mineral dust through an antioxidant mechanism. Silica that has been chemically altered by calcination was unable to activate AM eicosanoid production in vitro when compared to untreated, freshly fractured silica. These findings suggest that the mechanism by which dust particles can activate AM eicosanoid release may involve interaction of surface and/or soluble factors with the cell membrane. Taken together, these studies point to the involvement of AM eicosanoid production as part of the proinflammatory response of this cell to occupational inhalation of mineral dust. - Environ Health Perspect 102(Suppl 10):97-100 (1994)

Dec 1, 1995

Determine the appropriate spacing and alarm levels for carbon monoxide and smoke sensors used for fire detection in underground coal mine conveyor belt entries. Background Fire represents one of the most severe hazards in underground coal mines. Early-warning fire detection in underground coal mines is essential to successfully implement and execute evacuation and control measures. Both carbon monoxide (CO) and smoke sensors have the ability to provide reliable early-warning capability, provided that they are spaced properly and set at the appropriate alarm levels. The U.S. Bureau of Mines conducted a series of large-scale experiments where a small coal fire was used to ignite a conveyor belt at air velocities of 0.76 to 6.1 m/s. The test configuration was purposely designed to model a worst-case fire scenario for fires that develop within conveyor belt entries in underground coal mines. During the tests, CO and smoke levels were continuously measured to determine alarm times and alarm levels as the fire intensity progressed. The data from these tests indicated that for a given sensor spacing, the time to reach a preset alarm threshold depends upon the belt entry air velocity and cross-sectional area. Analysis of this data resulted in the equations and nomographs for CO and smoke sensor spacing, and alarm levels contained in Bureau of Mines RI 9380, "Fire Detection for Conveyor Belt Entries."

Jan 1, 1993

By F. W. Richard

This paper describing the mining practices at the Ground Hog Unit of the Asarco Mining Co., a subsidiary of the American Smelting and Refining Co., is one of a series being prepared by the United States Bureau of Mines on mining methods, practices, and costs in the various mining districts of the United Stated. The Ground Hog mine is at Vanadium in the Central mining district, Grant County, N. Mex., about 1.0 miles east of Silver City and 2 ½ miles southwest of Santa Rita. A branch line of the Atchison, Topeka & Santa Fe Railway connects Vanadium with Deming, about 45 miles southeast.

Jan 1, 1930

By Lewis C. Karrick

This paper is based on data obtained in the course of the oil - shale investigations of the U. S. Bureau of Mines , conducted in cooperation with the State of Utah . The amount and quality of oil that can be produced from any shale may be made to vary to an important degree by changing the temperature relations existing in the shale charge during destructive distillation . The rate at which the oil is formed from the shale is affected by the rate of heat supply , and therefore by the temperature of the shale during its thermal de composition . The quality of the oil formed may be controlled by altering the temperature of the shale , and therefore , the rate of formation of the oil . Variations in the yield and quality of shale oils may be caused by inherent properties of the retort used , but in any event the properties of the crude oil and yield are very largely the result of the extent to which the thermal de composition has progressed . Recognition of these principles will aid in explaining to a large degree the reasons for the wide variations in oils produced from the same shales by different " processes " . These principles also may be applied in the operation of different types of retorts in order that crude oils of a type most profitable to the operator may be produced . The Bureau of Mines has conducted an extended series of tests in the dee structive distillation of oil shales , in order to determine the wide variations that may be effected in the quality and yield of shale oil by changing the rate and temperature at which the oil is formed . These tests furnished interesting information on the four related points : yield of oil , quality of oil , temperatures required to distill shales , and time required for distillation .

Mar 1, 1923

By R. V. Lundquist

Lime-soda sinters, made and processed for recovering alumina and soda, consisted of several types of compound structures differing from the ideal dicalcium silicate and sodium aluminate. Many or these compound structures were causes for low alumina recovery and contributed to the relation or leach slurries. Presence or free lime, whether in the sinter or released by hydrolysis of sinter compounds, contributed to relation of leach slurries. Free lime tends to establish the initial viscosity assumed by a leach slurry. Previous investigations by the Bureau of Mines (1, 4)4/ and by other laboratories (5) have demonstrated the technical applicability of the lime-soda sinter process to the recovery of alumina from aluminum silicate materials. The basic concept of the process is sintering aluminum silicate materials with limestone and soda ash for the production of dicalcium silicate and sodium aluminate and then extracting the sodium aluminate by leaching the sinter in causticized liquors. Alumina is precipitated from the pregnant liquors by carbonating with carbon dioxide. Reaction in the sintering operation may be represented by the following simplified equation: A1203?SiO + 2CaCO3 + Na2C03 = 2Ca0?SiO + Na20?Al203 + 3C02

Jan 1, 1960