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Reduce the dust exposure to the operator of a longwall shearer with a novel foam spray system. Approach Discharge foam through the nozzles of a shearer drum so that foam and coal are better mixed. How It Works Bureau of Mines research showed that two very important principles for successful application of foam are: (1) moisture distribution and (2) degree of mixing. Foam can distribute a given quantity of moisture much more evenly over a large surface area. Successful Bureau tests of foam for dust control always involve a high degree of mixing between the foam and the material, Mixing, permits a greater distribution of foam throughout the mined product. The most suitable location of foam application would be at the point where the dust is generated, before the dust becomes airborne. Foam nozzles located in the cutter drum (pick face foaming or ejecting foam through scroll sprays) will suppress dust close to its source.

Jan 1, 1989

By J. K. Whyatt, B. G. White

Various methods of monitoring slip movements on bedding planes, as well as examination of rock burst damage in stopes, suggest that many rock bursts in the Lucky Friday Mine are closely associated with these movements. Slip displacements along bedding simultaneously reduce the physical dimensions of stopes and increase compressive stress along stope margins. Such changes, in turn, contribute directly to sudden failures of rock and cemented sandfill surrounding stopes. We believe that the reduction of rock burst hazards must be based on a clear understanding of the basic mechanisms involved. The current work emphasizes the mechanical role of wall rock movement and seismicity in generating conditions that promote rock burst damage. Based on our interpretations of these mechanisms, we briefly address several hypothetical practices that could influence rock burst hazards in similar mining situations. The overall goal of this research is to advance the NIOSH mission of improving the health and safety of the nation’s workers.

Provide means for rapidly re-establishing ventilation control in metal mines after blasting, for emergency applications, and for routine temporary use. Approach Two quickly-installed, parachute-like stoppings have been developed and tested by the Bureau's Pittsburgh Mining and Safety Research Center. How the Parachute Stopping Works The parachute stopping can be fastened to an existing anchor point, opened, and effectively block the air flow, in less than two minutes. Because the parachute stopping tends to be self-scaling, its performance is generally better than that of conventional fabric stopping. However, the periphery of the parachute stopping must be longer than the periphery of the mine opening, Figure 1 shows the parachute stopping deployed in a mine entry. To reduce leakage during routine use, the cloth at the periphery of the parachute stopping can be adjusted and then anchored at several points as necessary. This extra adjustment can also be done after the initial installation during mine rescue or mine recovery.

Jan 1, 1977

By T. T. Campbell

This report describes the development of new electroplating baths from which tin-nickel alloy plate was deposited. Although tin-nickel plate can be deposited from an aqueous ammonium bifluoride bath, the corrosive nature of this bath has served as a deterrent to its use. The Bureau of Mines felt that more general acceptance of this new alloy plate would follow if neutral or alkaline baths could be developed. Promising results were obtained from electrolytes containing both tin and nickel chlorides dissolved in triethanolamine-hydrochloric acid or in ethylene glycol hydrochloric acid baths. Current efficiencies close to 100 percent were obtained with these baths. Research revealed that tin-nickel plate could be produced from organic solvents or from mixed aqueous-organic electrolytes. The composition of the alloy deposit - 65 percent tin and 35 percent nickel - was found to exhibit the same single-phase structure that is obtained from the commercially accepted fluoride-type bath.

Jan 1, 1959

By A. R. T. Denues, A. P. Rowles

"INTRODUCTION Summarized data developed by J. E. Crawshaw and E.J. Murphy, 4/of the Explosives Division of the Bureau of Mines, suggesting marked variations in oxygen condition in three permissible explosives, have been reported 5/. Such variation is of interest in other work, it having been shown, for example, that the oxygen condition may have marked effect upon the products 3/ and the propulsive strength 7/ of explosives. It seemed that a more detailed presentation and more usual statistical analysis of these data might be of considerable general interest and not complemented in the literature.This report presents both the original data developed by Crawshaw and Murphy and the results of a simplified but seemingly acceptable statistical analysis of these data. The logical ground for this analysis might seem somewhat questionable because of the lack of systematic information concerning the extent of errors in the analytical procedure but the data show that there are several cogent and seemingly unequivocal indications of real heterogeneity in the explosives."

Jun 1, 1942

By S. Ralph Austin

Emanation coefficients of 950 samples of domestic uranium ore were successfully and rapidly determined with fair precision by modifications of the closed-can, gamma-only assay method, using commercially available or similar equipment. Coefficients range from <1 to 91 percent. Emanation varies considerably within each mine and area, but distinct differences among major mining areas were found, ranging from 7.5 percent for Moss Back Member, Chinle Formation, Southwest Lisbon Valley, Utah, to 56.6 percent for Ft. Union Formation (?), Powder River Basin, Wyoming. Coefficients also vary with (1) uranium mineralogy; (2) radium mineralogy; (3) lithology of host rocks; (4) grain size of uranium and radium minerals; (5) comminution of ore; (6) estimated porosity and permeability; (7) moisture content; (8) ore grade; (9) supposed mobility of deposits; age of deposits is unknown but limited by (10) age of host rocks which shows only doubtful correlation with emanation. Data obtained may be used to evaluate effects of investigated parameters on radon concentration in mines and thus to select efficient control measures. Drill-core emanation data allow estimates of probable radon problems in undeveloped deposits.

Jan 1, 1978

By P. G. Pigott

This Bureau of Mines laboratory research demonstrated that building bricks meeting ASTM specification C62-66 for grades SW and MW of FBS-type bricks can be produced from waste copper mill tailings. Waste tailings from accumulations at Magna, Utah, Anaconda, Mont., and Hayden, Miami, and San Manuel, Ariz., were dry-pressed into bricks, and the products were tested in accordance with ASTM Designation C67-66 on sampling, and testing of brick. An evaluation derived from pilot-plant production of similar brick at the Coal Research Bureau of West Virginia University indicated the production cost to be about $34 per 1,000 bricks. Utilization of such mill tailings on a commercial scale would eliminate the need for digging new pits for brick raw material production, conserve natural resources, and simultaneously remove potential sources of air pollution.

Jan 1, 1971

West Virginia ranks second in the nation in coal production, surpassed only by Wyoming, and usually accounts for 15 to 20percent of the nation&apos;s total annual production. Cod occurs in seams of minable thickness in all but nine of the state&apos;s 55 counties. There are two coal- producing regions, the northern field and the southern field. West Virginia coal is mined by both underground and surface methods. Underground mines in West Virginia account for a major portion of its coal production. Surface mines are generally contour operations and, especially in the southern field, are in steep slope areas, with slopes greater than 20 degrees. Many of the surface mines remove multiple seams. Recoverable reserves in West Virginia total in excess of 55 billion tons of bituminous coal. West Virginia&apos;s regulatory program was conditionally approved on January 19, 198 1. Its Abandoned Mine Land Program was approved February 23,198 1, with emergency authority granted on August 26,1988.

Jan 1, 1992

By Sean Gallagher

Bolting large sheets of wire mesh screen (WMS) to the roof of underground mines prevents injuries due to rock falls. However, WMS can be heavy and awkward to lift and transport, and may result in significant spinal loading. Accordingly, six male subjects (mean age =45.8 years + 7.5 SD) were recruited to lift WMS in a laboratory investigation of the biomechanical demands. Biomechanical modeling was used to estimate external moments about L5-S1 for sixteen lifting tasks, using two sizes of WMS. Full-size WMS involved a two-person lift, while half-size WMS involved a one-person lift. Lifts were performed under 168 cm and 213 cm vertical space. Restriction in vertical space increased the maximum L5-S1 extensor moment from 254 to 274 Nm and right lateral bending moment from 195 to 251 Nm. Lifting full sheets of screen (as opposed to half sheets) resulted in an average 33 Nm increase in L5-S1 extensor moment. The L5-S1 extensor moment was increased by an average of 44 Nm (18%) when lifting screens positioned flat on the floor compared to an upright position. Relevance to industry: Large flexible materials are commonly lifted in industrial work environments, and may involve the efforts of two or more workers. The current study examines the low back loading associated with lifting large flexible screens and presents recommendations to reduce spine loading.

Jan 1, 2009

By K. Thirumalai

This study forms a part of Bureau of Mines continuing research on thermal fragmentation of rocks. The potential of internal heating techniques for rock fragmentation is discussed. A concept of rock fragmentation with rapid inter¬nal heating of a localized inner volume of rock is advanced The energy required for rock fragmentation is made available by creating a required vol¬ume of localized heating. The fragmentation of rock using the proposed method is analyzed and qualitatively compared with the results of experiments with Charcoal granite, Dresser basalt, and Sioux Quartzite. High frequency dielec¬tric heating below 100 MHz is used in the study as an example to examine the working of the concept. The selection of operating conditions for the experi¬mental heating is explained. Fragmentation of Charcoal granite and Dresser basalt test rock blocks is achieved for localized heating below 550° C. The heated volume required for fragmentation is observed to be less than 2 percent of the test block volume and the electrical energy consumption is in the order of 3.5 to 6 5 kwhr/m3 The method offers a possibility for in situ fragmenta¬tion of rocks, favorable for internal heating. The method is highly dependent on rock properties governing internal heat generation The efficiency of dielectric heating in the experimental study is observed to increase with increasing dielectric loss of the rock material, ranging from about 10 percent in Sioux. Quartzite to about 50 percent in Dresses basalt

Jan 1, 1970

By Z. J. Fink

Ultraviolet-visible and infrared emission spectra from propagating methane-coal-dust-inhibitor mixtures have been obtained in a 0.2-by 0.2¬by 5.3-m vertical duct over a range of flame speeds from 2 to 100 m/sec. Results serve as a basis for the design and evaluation of thermal radiation detectors for triggered barriers that suppress ongoing mine explosions. Of particular significance is the large continua superimposed on the methane-air spectra when small amounts of coal dust are present and the variation of emissivity with infrared (IR) wavelength in dust flames. In conjunction with the spectral measurements, studies of flame speed, particle size, gas sampling plus thermodynamics, and dust sampling are presented and discussed in order to gain insight into the more fundamental aspects of propagating explosions. Sampling results have shown that only a near-stoichiometric amount of dust is consumed in the flames studied even though initial concentrations are five times stoichiometric. Difficulty in propagating coal-dust inhibitor flames of realistic mine characteristics in a cold-walled laboratory duct has been encountered. A simplified analysis of the flame zone utilizing spectral and sampling results indicates that the stability of slowly propagating flames is more dependent upon thermal radiation than upon convection losses to the walls. It is predicted that thermal radiation losses will make any measurements of coal dust burning velocities, "quenching diameters," or flammability limits more apparatus dependent than those corresponding to gaseous fuels.

Jan 1, 1974

By John R. Zelonka

Models made by encasing strain-gage networks in epoxy are described and evaluated. With this technique relatively complex models can be constructed in which any number of gages can be located and alined precisely. Although the gages are an integral part of the model matrix, they create no important mechanical or thermal stresses. Model construction techniques and experimental data proved reproducible and reliable. In addition, the sGlution obtained with these models to the problem of the state of stress around a circular hole in a plate subject to a plane stress condition was in agreement with theoretical, photoelastic, and finite-element solutions.

Jan 1, 1970

By Frank J. Cservenyak

Curtailment of bauxite importation by enemy activities during World War II focused attention on the necessity of developing domestic deposits of aluminous materials. Large quantities of aluminum ores such as kaolin, siliceous bauxites, high-iron bauxites, anorthosite, and diaspore clays are available but not readily amenable to Bayer processing because of excessive impurities. The Bayer process, which is the only commercial method in use in the United States for producing metallurgical-grade alumina, requires a high Al2O3 bauxite relatively low in SiO2 and Fe2O3. The Bureau of Mines was charged by Congress to investigate processes for the production of alumina from these low-grade ores. One part of the program was an investigation, in the laboratory and pilot plant, of the recovery of alumina by the lime-soda sinter process. Ores comprising kaolin, diasporic clays, anorthosite, and siliceous bauxites have been investigated and studied in the laboratory and pilot plant, and a series &apos;of reports covering these investigations has been prepared.

Jan 1, 1948

By Roy L. Wilfong

The thermal decomposition of the ammonium sulfate, carbonate, nitrate, oxalate, and sulfate salts of praseodymium, neodymium, and samarium was investigated thermogravimetrically in the temperature range 25° to 1,500° C. Each salt was decomposed at a heating rate of 2.5° C, per minute. The pyrolytic sequences have been identified and the temperatures of formation of inter-mediates, the minimum oxide formation temperatures, and values for loss on ignition have been determined. The nonstoichiometric ranges between Pr6011 and Pr203 and the extent of these ranges have been determined for oxides derived from the carbonate, nitrate, and oxalate salts of praseodymium. The alum and sulfate salts of praseodymium produced the sesquioxide without forming the intermediate non-stoichiometric oxides. The temperature limits of formation and regions of stability for the alums and sulfates were better defined than were those for the carbonates, nitrates, and oxalates. The minimum oxide formation temperature increased in the order of samarium, neodymium, and praseodymium irrespective of the anion.

Jan 1, 1962

By W. C. Babcock

This report covers Phase V of .a continuing program to apply a new liquid membrane process called coupled transport to the recovery pf metals from hydrometallurgical leach solutions. During this phase of the program, a membrane system of moderate scale was constructed and field-tested at the Exxon Highlands Mine and Mill Co. site near Douglas, Wyoming. The test unit contained four hollow-fiber membrane modules, each with 100 ft2 of membrane area. In the field tests, about 1000 gallons per day of leach solution was processed. The unit was operated on the leach solution for about 50 days. Leach solution entering the unit contained 100 ppm uranium. This concentration was reduced to about 5 ppm by coupled-transport treatment, and the uranium was concentrated to about 2 wt% as a uranyl carbonate product. Under these conditions, a transmembrane uranium flux of about 2.5 lb/ft2-year was obtained. An economic analysis showed that the cost of recovering uranium from this leach solution via coupled trans-port is about $1.20/lb. At higher concentrations of uranium in the leach solution this cost is reduced. For example, at 1000 ppm the cost of uranium recovery is about $0.30/lb.

Jan 1, 1983

By Leon W. Dupuy

Marquette&apos;s first reported the existence of iron In Missouri in 1673. Recorded production wan begun in 1815, increasing in size and importance until 1888, when the low price of iron resulting from Minnesota&apos;s production of high-grade ore caused most of the operators to close down. Missouri&apos;s iron production came from three types of ore: (l) Brown ores, including the deposits of primary and secondary limonites in southeast and southwest Missouri, (2) hematites of the filled sinks, including the ores of Central Ozark district, and (3) specular ores in porphyry, including the deposits of the St. Francois Mountains.

Jan 1, 1949

By T. L. Johnston

The Dobbins property, about 4-1/2 miles northeast of Cartersville, Ga., was fist operated in 1866, it is the oldest manganese mine in Georgia and one of the oldest minus in the United States still producing manganese ore. Changes in ownership, lessees, and operators and lack of records prevent the compiling of statistics regarding total production of ore from the property.

Jan 1, 1942

By T. L. Johnston

The Dobbins property about 4-1/2 miles northeast of Cartersville, Ga., was first operated in 1866. It is the oldest manganese mine in Georgia and one of the oldest mines in the United States still producing manganese ore. Changes in ownership lessees and operators and lack of records prevent the compiling of statistics regarding total production of ore from the property

Jan 1, 1942

By Tyler Blake

This report describes a study designed to evaluate a pro-posed modification in the cap lamp battery cord intented to reduce the incidence of snagging and catching of the cord. A three phase evaluation was performed comparing a prototype with the standard, currently available cord. First, a ?pull test? equipment was run. The second evaluation was a body conformity study. The third evaluation involved subjects performing common tasks in a low seam coal mine simulator. The results of these evaluations clearly demonstrated significant safety advantages of incorporating coiled cord into the design of the cap cord. The coil cord presented less of a snagging hazard, allowed the wearer more time to respond to a snag, and transmitted lower levels of force to the helmet when snagged. The research team recommended that cap lamp cords be commercially developed which incorporate coiled cord at the battery and helmet.

Jan 1, 1980

By G. E. Rennick

An oil well penetrating the Pittsburgh bituminous coalbed in northern West Virginia was plugged and safely mined through 3 months later. A sensitive chemical tracer, introduced into the oil reservoir before the test, was not detected in the mine air following the plugging and during mining of the pillar and penetration of the well. Effectiveness of the plugging in preventing reservoir gas from entering the mine through the well hole was verified by continuous monitoring of the mine air for indications of sulfur hexafluoride, an inert gas detectable in amounts as minute as 1/2 part per billion. Expandable cement and fly ash-gel-water slurry were utilized to seal the well above and below the coal seam. Three other wells were also plugged using various techniques.

Jan 1, 1972