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By L. L. Oden

The Bureau of Mines is conducting research to develop methanation catalysts for converting synthesis gas derived from coal to synthetic natural gas. This report describes a method to prepare supported Raney nickel coatings by dipping screen-covered nickel sheet in molten aluminum-nickel alloy. Coatings were formed at 1,050° C that were comparable in thickness, composition, microstructure, and catalytic properties to flame-sprayed commercially pre-pared Raney nickel. A molten salt comprising cryolite-8 wt-pct LiF was employed over the molten metal bath to clean and preheat the substrates, to protect the metal bath from oxidation, and to heattreat the coated specimens. Immediately following heat treatment, specimens were quenched to 700° C in a molten salt bath containing CaC12-34.5 wt-pct NaCl, which also functioned to remove the insoluble occluded fluoride salt.

Jan 1, 1976

By D. S. Harper, C. O. Carman

A German coal planer was put in operation in the Keystone mine of the Eastern Associated Coal Corp. , Keystone , W. Va . , in August 1960 . At present , the planer is mining in the fourth panel . The blocks of coal mined were 340 by 1,900 feet in panel 1 , 340 by 1,660 feet in panel 2 , 590 by 1,900 feet in panel 3 , and panel 4 , currently being mined , is 590 by 1,900 feet . Almost one- half million tons of coal have been mined from these four panels . An 11 - man crew handles the complete planer operation and produces an average of 500 tons of clean coal per shift . Self - advancing hydraulic props are used to support the roof over the entire face . Roof control and action on all of the panels has been highly satisfactory . During periods of extreme pressure , some additional support is required in the tail entry where evidence of weight from the retreating longwall extends about 200 feet outby the face . The time lost from production by moving equipment between panels has been reduced steadily . The move from panel 3 to panel 4 required 5 days , but it is believed that even that time could be reduced .

Jan 1, 1963

By F. K. McIntosh, L. A. Dahmers

"INTRODUCTION North Carolina has been the leading producer of mica in the United States, accounting for roughly 50 percent of the Nation's output. The producing area is a belt some 100 miles in width lying in the Mountain and Piedmont sections in the western part of the State. Ashe, Watauga, Avery, Mitchell, Yancey, Buncombe, Haywood, Jackson, Macon, Transylvania, Rutherford, Cleveland, and Lincoln Counties supply the bulk of production, while small amounts have been produced in Gaston, Catawba, Burke, Wilkes, Yadkin, Stokes, and Person Counties.To assist the operators and expedite the production of mica during the recent emergency, the Bureau of Mines drilled four of the more promising mica properties in this State. The results of this exploratory program are recorded in this report.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Division, L. B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, O. C. Ralston, chief, analyzes samples and makes beneficiation tests."

Apr 1, 1948

By R. G. Dressler

The Federal Bureau of Mines designed, constructed, and operated a demonstration plant at Louisiana, Mo., to produce gasoline, liquid fuels, and organic compounds from coal by a modified Fischer-Tropsch gas-synthesis process. Satisfactory equipment was developed to produce and purify synthesis gas and convert it into the desired products. Coal or coke was gasified with oxygen and steam to make a gas consisting essentially of carbon monoxide, hydrogen, and carbon dioxide. Dust in the raw gas was removed by cyclone separation, water scrubbing, and electrostatic precipitation. Carbon dioxide, hydrogen sulfide, and organic sulfur were removed with diethanolamine, iron oxide, and activated carbon. The gas was passed over iron catalyst and was converted into synthetic liquids, which were then separated and fractionated into gasoline, diesel oil, other liquid fuels, and oxygenated organic compounds. A 39-day continuous run demonstrated the feasibility of the process. Addition of 3 milliliters of tetraethylead per gallon of upgraded (or finished) gasoline gave a product with an octane rating up to 90 by the research method. After a caustic wash, the diesel oil was of a superior quality; its cetane number was 60 or above.

Jan 1, 1961

By N. A. Gokcen

In this Bureau of Mines report, appropriate equations correlating the activity of water with the activities of electrolytes in binary and multicomponent solutions have been derived for computer calculation. It was found that the half-integer power series are far superior to the integer power series, for both types of series having the same number of terms. The pro-posed method of calculation is capable of accurately yielding the activities of all components from the measurements of the activity of a single component at various concentrations. This method replaces the cumbersome and objection-able method of graphical integration of the Gibbs-Duhem equation. Two novel methods are proposed for determination of activities of electrolyte solutions important in hydrometallurgy; (1) Water vapor pressure measurement by differential pressure transducers having an accuracy of 0.001 pet, and (2) transpiration method with an inert gas bubbled through concentrated solutions followed by the analysis of the evaporated and redissolved electrolytes with specific ion electrodes having a sensitivity of ±10-10 molal. The first method is suitable for nonvolatile electrolytes, and the second, for volatile electrolytes such as hydrogen halides, HN03, H2S03, etc. The existing methods of estimation of ionic activities have been surveyed, and the best method has been selected, discussed, and summarized.

Jan 1, 1979

By Kenneth E. Hjelmstad

The U.S. Bureau of Mines (USBM) has developed an electromagnetic (EM) fire warning alarm sys-tem for underground mines. The system generates a magnetic field for through-the-earth signal trans-mission to microreceivers carried by individual miners. EM fields can induce electric currents in metallic conductors; if an EM transmitting antenna and an electric blasting cap array are too close, the field could induce a current in the blasting array and cause an unintentional initiation of the electric detonators. The USBM conducted tests that define the safe and unsafe regions for using electric detonators near the transmitting antenna of the warning alarm system. The minimum safe distance between a transmitting antenna and a blasting array is the distance where the induced electrical current in the blasting array is 50 mA, which is the safe current level specified in Federal mine safety regulations. Tests indicate that at transmitting power levels of 100-and 1,000-W, separation distances of 9 and 21 m, respectively, were required. These distances are small compared with the dimensions of a mine. Thus, the tests indicate that, with proper placement of the transmitting antenna, the warning system can be used safely in the proximity of blasting arrays.

Jan 1, 2010

By H. D. Baylor

This paper, describing the operations of the Louisville Cement Co. in quarrying limestone for the manufacture of quicklime, is one of a series being prepared for and published by the United States Bureau of Mines on stone quarries throughout the United States. Those papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating only and not total costs. It is recognized that publication of total costs might in many instances cause embarrassment to individual operators as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. ACKNOWLEDGMENTS The author acknowledges the assistance of J. H. Lemmon, plant superintendent, Charles Taylor, plant engineer, and F. H. Compton, chief engineer, of the Louisville Cement Co. in the compilation and preparation of this paper.

Jan 1, 1932

By H. J. Heinen

A technique offering promise as a metallurgical processing sequence the recovery of molybdenum (Mo) from the sulfide mineral--molybdenite?was investigated. The method consists of two steps: (1) electrosynthesis of pure dimolybdenum carbide (Mo2C) from molybdenite (MoS2) and (2) interaction of Mo2C and molybdic oxide (MoO3) to produce pure molybdenum metal. Two molten salt systems were satisfactory for electrosynthesizing Mo2C. The first was a mixture of potassium chloride (KCl), potassium fluoride (KY), and sodium metasilicate (Na2SiO3), and the second consisted of sodium fluoride (NaF), KF, sodium tetraborate (Na2B4O7), and sodium carbonate (Na2CO3). Yields up to 0.42 gram of Mo2C per ampere-hour were obtained. The carbide, mixed with monitored amounts of MoO3, was converted to molybdenum metal of 99.9 percent purity by sintering at 1,500° C.

Jan 1, 1965

By Thomas E. Green

A combined solvent extract ion-spectrophotometric method for the determination of as little as 1 ppm of copper in tungsten metal or tungstic oxide has been developed and evaluated. Metallic samples are converted to tungstic oxide by treatment with hydrofluoric and nitric acids. The oxide is then dissolved in sodium hydroxide, and the copper is extracted as the colored neocuproine complex. Total elapsed time for the analysis is approximately 1-1/2 days; however, actual working time for a group of six or eight determinations is less than 4 hours. Precision at the 2-ppm level is better than 0.1 ppm.

Jan 1, 1963

By John P. Wagner

The details of a three-phase study (total time period of 12 months) entitled ?Fire Alert Systems for Metal and Non-Metal Mines,? are presented. Phase 1 consists of a state of the art survey on fire detection devices and gas sensing techniques. Phases 2 and 3 include laboratory screening and systems concepts testing on various detectors classified as products of combustion, optical view-field and contact (or thermal) types under incipient and flaming combustion conditions. Recommendations for a mine fire detection system to protect shaft, sealed off or mined out (from spontaneous combustion of sulfide containing ores and cellulosic materials), and fuel storage areas are also included. me principal problem area noted during Phase 1 study is the high expected occurrence of false alarming of products of combustion detectors (POC") subjected to normal mining operations---diesel vehicles and equipment and shot firing or blasting operations. Simultaneous gas sensing of either the ratio of CO/NOx or CO2/NOx with detection of one or more fire signatures (smoke, radiant energy, or heat sensing) is the recommended approach to discriminate against these operations.

Jan 1, 1975

By J. O. Merritt

The primary objective of this research program was to recommend ranges of minimum luminance for safety in underground metal and nonmetal mining. Visual tasks critical to safety were identified and rank-ordered. Realistic, full-scale, dynamic task simulations encompassing the most important visual components of the critical tasks were installed in a large simulated workspace. Five trained observers performed the six simulated mining tasks under varying levels of luminance. Over 13,000 measurements of visual task performance were used in developing minimum luminance recommendations for the on-foot underground worker and the mobile equipment operator.

Jan 1, 1983

By R. D. Dey, V. Castranova, J. M. Antonini, J. A. Blackford Jr.

Alveolar macrophages (AM) exposed to cytokines or bacterial lipopolysaccharide (LPS) produce the free radical nitric oxide (NO·) by an inducible nitric oxide synthase (iNOS). They also release reactive oxygen free radicals following exposure to silica dust. The purpose of the present study was to determine whether NO· is produced by rat AM and/or recruited leukocytes following the intratracheal (IT) instillation of silica. Male Sprague-Dawley rats (175 to 225 g) were IT instilled with either silica dust (10 mg/100 g body wt) or LPS (0.25 mg/100 g body wt). After 24 h, bronchoalveolar lavage cells (BALC) and lavaged lung tissue were assayed for iNOS mRNA. Cell counts of BALC and iNOS-dependent (Nw-nitro-Larginine methyl ester [L-NAME]-inhibitable) chemiluminescence generated by AM were also determined. Northern blot analysis demonstrated that the steady-state levels of BALC iNOS mRNA were significantly increased by 3-fold following IT silica and by 7-fold following IT LPS. Partially enriched fractions of either AM or leukocytes from silica-treated rats both exhibited significantly elevated iNOS mRNA in Northern analysis. iNOS-dependent chemiluminescence was significantly increased in AM by 36-fold following IT silica and by 89-fold following IT LPS. Differential counts of BALC showed that AM numbers did not change in any of the treatments; however, red blood cells increased by 30-fold following IT silica and by 23-fold following IT LPS. Total leukocytes (polymorphonuclear leukocytes plus lymphocytes) increased by 58-fold following IT silica and by 274-fold following IT LPS. The results demonstrate that AM and neutrophils iNOS steady-state mRNA levels, AM iNOS-dependent chemiluminescence, and lavagable red blood cells and leukocytes all increased following IT silica. These findings suggest that NO· production in rat AM and neutrophils is increased in response to silica. NO· has the ability to then combine with superoxide and form a highly reactive toxic species, peroxynitrite, which may be responsible in part for silica-induced lung damage.

Dec 1, 1995

By David E. Siskind

The Bureau of Mines has studied the fracturing and associated damage occurring in the vicinity of blastholes from five shots fired in the shale pillars in the White Pine copper mine, White Pine, Mich. Four types of explosives (AN-FO, commercial extra dynamite, ammonia gelatin dynamite, and a low-density, low-velocity permissible) were used. Cores were taken from the blast region and examined by ultrasonic and petrographic techniques. Pulse wave velocities were measured across the core diameters, and thin sections showing cracks and changes in lithology were examined in an attempt to establish zones of damage. Cores from the blast regions and areas near pillar free faces were found to have abnormally low pulse velocities. Petrographic study of the thin sections showed that the negative velocity anomalies were caused by cracks in the cores. Crushing and extensive fracturing prevented meaningful measurements on core fragments from the immediate blast vicinities. Compositional, changes and other rock nonuniformities, such as joints and preexisting fractures, tended to mask detailed damage differences among the four explosives; however, the two most energetic explosives (extra dynamite and ammonia gelatin dynamite) produced damage zones two to three times as large as the AN-FO and low-velocity permissible explosives.

Jan 1, 1973

By G. W. Jones

Explosion hazards that may exist when air becomes polluted with combustible gases and vapors are extremely dangerous, particularly if the volume of gaseous atmosphere is large, and an explosion under such circumstances could do tremendous damage to persons and property. The hazard is even greater if explosive mixtures are confined under high pressure, as the pressure could increase to tremendous proportions just before the container would rupture. Because of its interest in safety in the mining and allied industries, the Federal Bureau of Mines has investigated the flammability (explosibility) of various types of combustible atmospheres and published its findings. The explosibility of natural gas has been studied, and the limits of flammability have been determined and published. Other investigations have shown how explosions of natural gas-air mixtures may be prevented by the addition of nitrogen and carbon dioxide.

Jan 1, 1949

The object of this program was to extend the capabilities of visual paging systems both in size and function. The system developed uses the mine pager phone line for communication, monitoring, and remote control. A central station, using a minicomputer, transmits signals by phase inversion modulation of a 16,384 Hz carrier to as many as 999 remote units. The remote unit addressed returns An echo to indicate that it is functioning and, in the case of monitor units, to convey the monitor data. Magnetically latched display dis[c]s, which can be seen from both sides when posted, are used for visual paging. Lists of the addresses of posted pages, unanswered pages, and non-echoing units are prepared by the central station computer. The system was designed to be intrinsically safe and should operate for three months on a 12-volt lantern battery.

Jan 1, 1980

By G. Stecklein

This report summarizes the results of research into the areas of the fragmentation and entrainment of Airborne Respirable Dust (ARD). The objectives of this program were four-fold: first, to review the present state of knowledge regarding ARD; second, to expand this state of knowledge through the identification of hypothetical microscopic mechanisms by which the coal is fragmented and the dust becomes entrained; third, to specify the informational requirements to verify or nullify these hypotheses; and fourth, to relate experimental techniques that will produce that required information. Additionally, insights are provided regarding potential methods of extraction and/or treatment which may reduce the concentration of ARD.

Jan 1, 1982

By M. H. Chetrick

An important factor in the design and operation of a lignite-gasification plant is knowledge of the thermal requirements. These not only vary with different-size plants but also with the operating conditions for a plant of given capacity. Thermal data have been collected since 1945 from a commercial-scale lignite-gasification pilot plant operated by the Bureau of Mines at Grand Forks, N. Dak. The description and operation of this plant and a study of the gas-composition data have already been described in previous reports (1, 2, 3, 4, 5).2) / This investigation was made to review the thermal data taken in tests and to correlate them in terms of the fraction of undecomposed steam and the H2:CO ratio.

Jan 1, 1953

By Andrew B. Cecala, Edward D. Thimons

The Bureau of Mines has successfully tested a method to simulate methane (CH~) flows from face areas through the returns of noncoal mines. This technique' involves releasing a small quantity of tracer gas at a working area and sampling for that gas downstream in the re- turn airways. By measuring the dilution of the tracer gas, the dilution of any volume of CH4 released at the face can be calculated. This information is useful in selecting locations for CH4 monitors and in deciding the necessity for permissible equipment in the returns.

Jan 1, 1984

By C. L. Klingman

In extracting helium from natural gas at Bureau of Mines helium plants, a continuous analysis of the helium content of inlet and outlet gas streams is required to determine extraction efficiency. An analyzer, using established principles of gas chromatography to effect the analysis, has been developed by the Bureau of Mines to meet this need. It will record the helium content of inlet or discharge gases from helium-extraction plants every five minutes, continuously, without the attendance of an operator. A 25-inch column of activated charcoal is used as a partitioning agent; nitrogen is the carrier gas; and a hot-wire, thermal-conductivity cell is the detector. A 1.0 mv, strip chart indicates the unbalance of the detector cell, Sample size is 0.37 cc, and carrier gas flow rate is 75 cc, per minute. Significant improvements in helium extraction have been demonstrated by using the chromatograph in three helium-extraction plants.

Jan 1, 1961

By A. Visnapuu

The Bureau of Mines, as a part of its goal to minimize occupational hazards associated with mining and mineral processing operations, has developed and field tested a compact exhaust air muffler for mechanized, jumbo-mounted pneumatic rock drills. The muffler is constructed of 1/8-inch sheet steel and has nominal dimensions of 1-3/4 by 9 by 13 inches. A directed air passage, flexible neoprene baffles, and an expandable slit-type outlet are incorporated to reduce drill exhaust air noise and eliminate muffler icing. Field tests in actual mining operations showed a l5-dbA reduction in exhaust noise and an 8-to 12-dbA reduction in overall drilling noise with no icing problems or decrease in drill performance. Data are presented on muffler construction, laboratory, and field test results.

Jan 1, 1979