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By James H. Russell

The Bureau of Mines used a statistical approach to evaluate the effects of temperature, current density, and composition of the electrolyte on the purity of boron prepared by electrolysis of a fused mixture of boric oxide in potassium fluoborate. The quadratic equation which best fits the data was calculated for a temperature of 650° to 850° C, a cathode current density of 40 to 1,150 amp/ft2,and a boric oxide content of 0.3 to 7.1 molal. The best products, better than 95 percent boron, were obtained when the current density was less than 2 amp/ft2 and the boric oxide content was less than 2 molal.

Jan 1, 1967

By Frederick H. Raab

The electromagnetic retransmission system is a new, automated method of locating trapped mine workers. This technique overcomes many 1 imitations inherent in electromagnetic direction finding by reducing the effects of the conducting ground to an acceptable maximum, by finding position accurately in the presence of antenna tilt, and by eliminating the need for the receiver to be located directly above the subsurface transmitter. Three transportable three-axis magnetic-dipole transmitters on the surface create a system of electronic grids in which the phases of the downlink Signals convey position information. The subsurface retransmitter modulates the uplink carrier of the existing beacon transmitter with the received downlink signal; the coal-pillar loop antenna is used for both receiving and transmitting. The uplink receiver uses a three-axis antenna and extensive digital signal processing. A small computer integrates data, estimates position, and controls system operation through VHF-FM communications. Both coal-mine and deep-mine operation are possible by selecting appropriate transmitting power and signal frequencies. This report shows such systems to be both feasible and practical.

Jan 1, 1980

By Oliver C. Ralston

The minerals that enter welding-rod coatings and fluxes are the main subject of this report. Few mineral producers know just what minerals and what grades and quantities of minerals are required by the welding trade, and it is for their information that this report has been prepared. The various methods of welding are discussed extensively enough to inform this type of audience. Specialists in welding probably will find little on welding that is of value to them, but they may learn something more about the minerals or mineral products that they use. The authors did not find it easy to prepare this publication, and any needed corrections will be welcomed. Regarding welding, research, Jenks4/ 1 points out that while the process of welding in simple in operation, the phenomena attending its use are extremely complicated, and the efficient and safe use of welding requires an understanding thereof. Although the fluxes and the coatings used have solved many problems, many other problems require the joint effort of the whole industry; therefore, it is hoped that this report will be found of practical value.

Jan 1, 1940

By Chas. F. Jackson

This paper is one of a series dealing with mining methods and costs, prepared and published under the sponsorship of the United States Bureau of Mines and made possible through the cooperation f many mining companies in the United States and foreign countries. The preparation of this paper follows a field study of top-slice mining during which the author visited and discussed with operating officials a large number of iron mines in the Lake Superior region. During this study special note was made of changes in top-slicing practice during the past decade, prior to which the author had acquired several years experience with the method through active connection with a number of mines employing top slicing.

Jan 1, 1931

By A. C. Fieldner

Much activity is called for in the present period of hightened national effort, and wise direction of such a program must always be conditioned by positive knowledge gained in years of slow and painstaking study and development. Research and technologic investigations on coal by the Bureau of Mines have been described in a series of annual

Jan 1, 1941

By Philip C. Tully

This bibliography contains 3,062 different citations to technical and scientific literature about helium and alpha-particles abstracted by 13 abstract service publications during 1963. Multiple subject classification has increased the total number of entries to almost 5,000. Helium citations are listed by 23 major classifications. The number of subclassifications has been greatly increased to minimize the time required for literature search. The use of automatic data processing has been extended in compiling the bibliography.

Jan 1, 1970

By Laxman S. Sundae

Laboratory tests were conducted at the U.S. Bureau of Mines to determine the effects of roof-bolt drilling parameters on penetration rate in sandstone using tungsten carbide alloy (WC-Co) and polycrystalline diamond compact (PDC) drill bits. During the tests, water pressure of 552 kPa was found to be adequate for removing the cuttings from the tops of drill holes. Test results show that for both types of bits, penetration rate increased when thrust was raised from 227 to 1,588 kg. When water pressure rose from 554± 120 to 1,344±350 kPa, the effect on penetration rate was not significantly different. Conventional WC-Co bits became dull when one or two holes were drilled, after which the penetration rate dropped dramatically. Microscopic examination shows that the cutting edges of PDC bits also become somewhat dull, but at a much lesser rate than WC-Co tips. Microscopic examination also reveals that the wear mechanism of WC-Co and PDC bits is quite different, which may explain the longer life of the PDC bits.

Jan 1, 2010

By A. C. Smith

The U.S. Bureau of Mines evaluated the effectiveness of automatic water sprinkler systems on the suppression of incipient and propagating conveyor belt fires under ventilated conditions. Large-scale experiments were performed at airflows ranging from 1.1 to 4.6 m/s. In incipient fire experiments with 100°C, standard-response sprinklers installed above and between the belts, the sprinklers activated later, the peak heat release rates were larger, and more belting was consumed at the higher airflow. In similar experiments with 74 °C, fast-response sprinklers, the sprinklers activated at the same heat release rate for both high and low airflows, but the peak heat release rate and amount of belting consumed was slightly higher at the lower airflow. In incipient fire experiments with sprinklers located only above the top belt, the heat release rate and amount of belting consumed was larger at the higher airflow. The propagating fire experiments showed that sprinklers located above and between the belts were effective in stopping flame propagation. Peak heat release rates and amount of belting consumed were larger at the higher airflows for both the 74 °C, fast-response and 100 °C, standard-response sprinklers. The sprinklers were equally effective at each airflow.

Jan 1, 2010

By Geo. H. Williamson

This paper describing the dredging operation of J. K. Davison & Bro. on the Allegheny River near Pittsburgh, Pa., is one of a series being prepared for and published by the United States Bureau of Mines on methods and costs of dredging sand and gravel in the United States. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures 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 wishes to acknowledge the assistance of H. R. Hissrich, chief engineer of the Goodman Engine and Machine Co., in compiling details of the dredge construction; of H. H. Stewart, auditor of J. K. Davison & Bro., in preparing cost and performance tables; and of J. R. Thoenen, mining engineer of the United States Bureau of Mines.

Jan 1, 1932

By Ralph Husack, J. W. Eckerd, G. A. Brady

The effect of gamma radiation on Pennsylvania anthracite and on reactions between anthracite and other materials was studied using a shielded , selfcontained 23,000 - curie cobalt 60 source . When anthracite was exposed to air at 65° C the reaction with oxygen was greater in the presence of radiation. than in its absence . Although drop- shatter tests indicated that exposure to radiation decreased the resistance to breakage of anthracite , this evidence of structural weakening was not supported by the results of grindability or particle- size studies . Irradiation caused definite changes in the gases evolved from evacuated samples of anthracite ; the percentages of hydrogen and carbon dioxide were increased, and the methane concentration remained unchanged . Carbon monoxide was evolved only from the unirradiated samples . Electron paramagnetic resonance (EPR ) measurements indicated large differences between evacuated samples and those exposed to air . There was little or no difference between irradiated and unirradiated samples , except that the free- radical content of unirradiated samples of anthracite increased progressively with higher temperatures of evacuation , but in the case of irradiated samples , no such behavior was found . Attempts to produce carbon disulfide and calcium carbide by reacting anthracite with sulfur up to 120 ° C , and with calcium oxide up to 400 ° C , were unsuccessful .

Jan 1, 1964

By Donna L. Anderson

This information circular documents the status of a laser-based guidance system to track and control the tramming maneuvers of a continuous mining machine. The work is part of a multiple project effort at the U.S. Bureau of Mines to develop technology for computer-assisted mining systems. The system includes stationary offboard laser-scanning sensors that report the angular coordinates of retroreflective targets on the mining machine. A microcomputer system processes the angular coordinates, determines position and heading, handles requests for data, and controls tram maneuvers of a continuous mining machine. This report describes the hardware for the sensor and computer systems and the software algorithms for continuous miner position and heading determination, closed-loop tramming, and data request handling. Improvements made to the system since previous documentation include the rewriting of the software on a stand-alone real-time microcomputer system, the implementation of real-time programming techniques, the use of a new version of the laser sensor, and the design and development of explosion-proof enclosures for the lasers and corresponding power supply.

Jan 1, 1991

By T. E. Howard

The western phosphate field, comprising parts of Idaho, Montana, Wyoming, and Utah, contains one of the world's largest known reserves of phosphate rock. Although phosphate-rock deposits of good-grade have been known since before the turn of the century and production has been recorded since 1906, real development of this important field did not begin until immediately after World War II. Since then fertilizer-manufacturing facilities using western phosphate rock have been expanded, and three electric-furnace plants for producing elemental phosphorus have been installed, resulting in a rise in mine production from 323,955 long tons2/ in 1945 to 1,653,916 long tons3/ in 1953. Interest in the field is increasing, and it is reasonable to expect that the western phosphate industry will continue to expand. Before 1945 all western production was from underground mines. In that year the first strip mine in the field was started near Montpelier, Idaho,~ and in sub-sequent years a number of other open-pit mines were opened in southeast Idaho and western Wyoming. At present the major part of the production comes from surface mines. Underground mining has continued, and new underground mines have been opened in the field, but recent exploration by operating companies has been aimed primarily at developing additional deposits suitable for low-cost surface mining. Preliminary reserve estimates by the Federal Geological Survey5/ indicate that only a very small part of the total resource may be recovered by surface methods and that the industry eventually must depend largely on underground mining. Because one function of the Bureau of Mines is promoting the conservation and development of the Nation's mineral resources, it is appropriate that research be conducted to develop low-cost maximum-recovery underground mining methods applicable to western phosphate-rock deposits.

Jan 1, 1956

By R. G. O'MEARA, Alexander M. Gow, W. T. SCHRENK

Lime is used extensively in the various industries. The National Lime Association in an excellent and recent bulletin lists 23 important in- dustries in which lime plays a vital role; and it thereby justifies the statement that "Lime is one of the most versatile and widely used reagents in the chemical and industrial world." There is, however, one application of this "universal" reagent which has not been mentioned. It is the use of lime in the flotation of ores. An appreciable percentage of the lime produc- tion is consumed by ore-dressing plants. The uses of lime throughout all the industries are more or less re- lated, but "lime" is a broad term; the varieties of lime are more mumerous than the limestones from which it is made, and its use involves a complicated technique. The interrelated application and growing importance of lime in flotation warrant this additional publication on the various "limes," with emphasis on those uses related to the function of lime in flotation. ཁྐྲ་ Lime in water treatment, cyaniding, and amalgamating will be men- tioned, after which its use in flotation will be taken up. This compendium was prepared by the Mississippi Valley Experiment Station of the United States Bureau of Mines and the Missouri School of Mines and Metallurgy, Rolla, Mo.

Apr 1, 1931

By J. B. Cheung

The results of a program to demonstrate the technical feasibility of hydraulic borehole coal mining are presented in this report. The hydraulic borehole method of coal mining involves inserting a hydraulic mining device into a borehole that has been drilled from the surface into the underground coal bed. The borehole mining device issues a jet of water under high pressure, which breaks the coal. These pieces of coal, along with the water, form a slurry, which flows to the base of the borehole where it is pumped to the -surface. Phase I of the program encompassed the design, fabrication and factory-testing of a hydraulic borehole mining device. The program was successfully completed with the field tests being conducted at the Wilkeson-Carbonado Coal Field near Wilkeson, Washington. The technical feasibility of hydraulic borehole coal mining was demonstrated by mining 32 tons of coal at a depth of about 75 ft over a period of 4 hours.

Jan 1, 1976

By Robert C. Merritt

Laboratory amenability studies as well as a pilot heap-leaching investigation of low-grade sandstone uranium ores from Wyoming, New Mexico, and Colorado are described. Sulfuric acid heap leaching with oxidation, for 120 days, extracted up to 98 percent, 90 percent, and 79 percent U308 from Wyoming, New Mexico, and Colorado ores, respectively.

Jan 1, 1976

Kaiser Aluminum & Chemical Corp. announced that it planned to spend $66 million to increase the efficiency of its Baton Rouge, Louisiana, alumina plant. The improvements are designed to reduce energy consumption but will not change the annual capacity of the plant, now rated at about one million short tons. The project was expected to be initiated immediately and be completed by 1982. ALUMINUM Producers in this country posted unalloyed 99.5 percent aluminum ingot at 53-57.5 cents per pound, yet actual selling prices were closer to 53 cents. Domestic merchants quoted unalloyed ingot on a spot basis at 54-56.3 cents. London Metal Exchange 3-month forward contracts fell during November's trading from 55,2 cents to 52.8 cents per pound.

Jan 1, 1978

By Kenneth M. Maas

The Bureau of Mines inventoried the land availability for mineral exploration and development in northern Alaska and compared this land with known mineral terranes and mineral deposits, to quantify the potential for favorable location of mining claims for metalliferous mineral deposits. This report includes thirty-three 1:500,000-scale maps that depict land availability, and the accompanying text and tables relate availability acreage to areas of favorable mineral terranes. Three categories of land availability and ownership are identified, along with 12 subcategories of land status. Available land comprises approximately 14.5 million acres or 16% of the 90.3-million-acre study area; land available with restrictions accounts for 7.5 million acres or 8%; and unavailable land encompasses 68.3 million acres or 76%. Mineral terranes underlie 37.8 million acres or 42% of the study area; 5.3 million acres or 14% are available for mineral location, 2.8 million acres or 7% are available with restrictions, and 29.7 million acres or 79% are unavailable. There are 500 known mineral deposits or occurrences within the study area. This includes 271 lode deposits, of which 171 lie within a recognized mineral terrane and 55 are on available land. The remaining 229 are placer deposits.

Jan 1, 1987

By D. L. Neylan

The Bureau of Mines evaluated various methods for identifying sources of mercury vapor in excess of the threshold limit value (TLV) of 0.05 mg of mercury per cubic meter of air set by the American Council of Government and Industrial Hygienists (ACGIH) for mines and mineral processing plants. Chemical spot tests and portable devices for mercury determination were evaluated, based on information from published sources and performance in laboratory tests. Among the parameters examined were sensitivity, interferences, cost, ease of use, and other factors pertinent to field application, More than 50 methods were evaluated. The investigators found that many readily available methods are suitable for identifying sources of mercury vapor in mines and mineral processing plants. The best method appears to be one that uses a commercially available mercury test paper sensitive only to mercuric ions. For some of the more promising chemical spot tests, this report includes step-by-step instructions for field application.

Jan 1, 1983

By Guy A. Johnson

To improve productivity and cut costs, modern underground mining operations have become more mechanized. This mechanization has increased the usage of fuels, hydraulics, and electrical equipment associated with diesel-powered vehicles, thereby also increasing the hazards of underground mine fires. The Bureau of Mines evaluated the fire hazard problem and assembled prototype components for a system that would automatically sense and extinguish fires on mobile underground equipment. The prototype system and alternative designs were in-mine-tested and proved effective. This report summarizes this technology, which can cost effectively help solve the problem of fire hazards on underground vehicles.

Jan 1, 1983

By E. G. King

Thermodynamic calculations involving the oxides of tungsten and molybdenum have been hampered by lack of accurate entropies and high temperature heat contents. This paper presents work by the Federal Bureau of Mines on new low-temperature heat-capacity data leading to the evaluation of the 298.15° K. entropies of tungsten dioxide and tungsten trioxide, as well as high-temperature heat contents (above 298.15° K.) of molybdenum dioxide, molybdenum tri-oxide, tungsten dioxide, and tungsten trioxide. Included are heats of fusion of the two trioxides. The heats of formation at 298.15° K. of these four oxides are tabulated as measured by Mah4 5/ of this laboratory. Included also are the 298.15° K. entropy of Mo02 measured by Kin 6/ of this laboratory, and that for Mo03 according to Kelley and King.7/ These basic data provide a consistent compilation from which to perform accurate thermodynamic calculations involving these compounds. No previous low-temperature- heat-capacity measurements have been reported for tungsten dioxide. Seltz, Dunkerley, and DeWitt8/ measured the low-temperature heat capacity of tungsten trioxide. The only previously-reported high-temperature heat-content measurements for any of the oxides were conducted by Cosgrove and Snyder,9/ who measured molybdenum trioxide to 1,300° K.

Jan 1, 1960