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By James H. Aase

Selected glacial lake clay deposits in Minnesota were sampled, tested, and evaluated to determine their suitability for use as a bonding agent in iron ore pellet manufacturing. Preliminary tests conducted on clay samples obtained from five ancient glacial lake basins identified the clays in the Lake Agassiz glacial lake basin near Cook, Minn., as having the greatest bonding potential. An auger drilling program was conducted to obtain substantial quantities of representative material for detailed testing. The drilling indicated the presence of large clay reserves in excess of 500 million tons within the 12-square-mile area investigated. Bench scale tests indicated that the bonding properties of Cook area clays, when activated with relatively small quantities of sodium carbonate monohydrate (Na2C03?H2O), imparted excellent strength characteristics to iron ore pellets. Larger scale continuous pelletizing tests were made to confirm the bench scale results. These tests indicated that use of 1 percent activated clay alone as binder gave the iron ore pellets an overall strength slightly lower than with 0.75 percent bentonite, considered the industry standard. Use of 0.5 percent activated clay plus 0.5 percent bentonite produced better pellet strength qualities than use of 0.75 percent bentonite alone, without increasing the silica plus alumina content. The data from both bench scale and larger scale continuous tests suggest that the Cook, Minn., clays can be utilized after activation either alone or in combination with bentonite at an economic advantage over present pelletizing practice with bentonite.

Jan 1, 1968

By D. A. O'Keefe, M. M. Wong

To obtain beryllium metal of higher purity , flakes produced from electrorefining scrap metal were used as cell feed for a second cycle of electrore fining at 500 ° C in an electrolyte composed of 51.7 mole - percent LiCl , 36.9 molepercent KC1 , and 11.4 mole - percent BeC¹ · Metallic impurities in the flakes totaled more than 108 ppm , the metallic impurities in the metal obtained from the two - cycle electrorefining were , with the exception of 35 ppm of calcium , below the spectrographic determination limits .

Jan 1, 1964

By Paul E. Loustaunau, Devah Galloway, Catherine Wetherby

This report describes a project in which Development of a Supervisory and Management Training Program for the Underground Coal Mining Industry was developed and evaluated. The project was carried out in two phases. The first phase was a research effort to develop specifications for the program. The second phase was a development and evaluation effort. In the second phase, training programs for first-line supervisors (section foremen) and for middle managers (mine/shift foremen and mine superintendents) were prepared in accordance with the specifications and evaluated by members of the industry. This report describes the project and presents the conclusions drawn there from.

Jan 5, 1983

By S. D. Maksirnovic, Fred N. Kissell

The use of vertical surface degasification boreholes with bleeder systems and the use of a timbered bleeder system to degasify gob areas were studied by (the Bureau of Mines. This report describes three gob degasification studies ,conducted in the Pittsburgh coalbed. One study was conducted to determine the number of panels degasified with one large borehole . The study showed that the borehole provided degasification for three panels. Another study was conducted during the retreat of a 35-acre panel with a single-entry and a two-entry bleeder system and a large surface borehole. A major portion of methane emitted from the panel was carried away by the bore- hole, leaving the bleeder entries relatively free of methane. The last study was made to determine the effectiveness of a timbered bleeder system. The bleeder entries successfully degasified the gob area when enough entries were available and adequate pressure was available to force the air through roof falls.

Jan 1, 1980

By K. K. Kershner

Important contributions can be made to conservation of natural resources by recovering mineral values from primary and secondary metallurgical slimes and flue dusts. This applies particularly to ultrafine mineral particles that escape recovery by conventional mineral dressing. In the interest of economy and conservation the Bureau of Mines is investigating fundamental properties of ultrafine mineral values in slimes as a means of developing new or improved methods of mineral recovery. The work described in this progress report was carried on in the Bureau's laboratories at Rolla, Mo., from 1951 to 1953. The mineral material used as a subject for study was tin-ore slimes. DESCRIPTION OF TIN SLIMES The tin slimes consist principally of quartz, with appreciable quantities of tourmaline and sericite mica and small amounts of cassiterite, pyrite, hematite, and arsenopyrite. The tin content is approximately 0.5 percent.

Jan 1, 1954

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Jan 1, 2012

By Joseph E. Matta

The Bureau of Mines conducted tests using a tracer-gas technique to measure the effectiveness of the jet fan, which is often employed in mines to ventilate dead headings. Results of these tests show that jet fans can (1) ventilate dead headings beyond the maximum penetration distance indicated by smoke-tube detection of air movement, and (2) redistribute available fresh air through larger working areas. However, if the fresh air base is insufficient, the fan will merely recirculate the contaminated air and disperse it over a larger volume.

Jan 1, 1978

By E. G. King

The work described in this Bureau of Mines report was undertaken to fill a need of industry for high-temperature heat-content data for uranium tetrafluoride. Without such data, heat balance evaluations of processes involving this substance are seriously hampered. Measurements of the heat content of uranium tetrafluoride were conducted at temperatures from 298° to 1,350° K. The melting point and heat of fusion were determined. The results are presented in suitable tabular form, and representative heat-content equations are included.

Jan 1, 1961

Large quantities of combustible materials are often found in underground metal and nonmetal mines, with support timber predominating. Wood lagging and timber, wires and cables, brattice cloth, hose, paper products, cardboard cartons, and wooden containers are additional combustible materials commonly found in underground storage areas. Shorted or overloaded electrical cables, worn sockets and plugs, spontaneous combustion, careless smoking, and welding and cutting are common fire ignition sources. Inexpensive, reliable fire detection and suppression systems are available to provide early warning and to extinguish fires that originate in underground storage areas.

Jan 1, 2011

By C. M. Frost

The hydrodesulfurization characteristics of a Venezuelan topped crude oil and a Venezuelan reduced crude oil were determined at temperatures from 740° to 850° F, pressures from 800 to 1,600 psig, and space velocities from 1.0 to 2.0 Vo/Vc/hr. Kinetic calculations showed that under these conditions the desulfurization reaction was first order with respect to sulfur and had an average activation energy of 32.5 kcal/mo1. Catalyst life tests made at 750° F, with pressures of 800, 1,200, and 1,600 psig and space velocities of 1.0 and 1.25 Vo/Ve/hr, showed that the decrease in the relative activity of the catalyst was a logarithmic function of time or volume of oil processed and the amount of vanadium deposited on the catalyst. Comparative tests made with residual fuels prepared from a Wilmington, Calif., crude oil and a Wyoming asphaltic crude oil showed that catalyst life may be extended by processing fuel oil with a low metal content, but it may be shortened by the presence of large amounts of asphalt in the feed.

Jan 1, 1971

By John C. Edwards

A two-dimensional, time-dependent, mathematical model has been developed that describes fire spread along the walls of a ventilated duct. The model is based on the assumption that the leading edge of the fire zone propagating along the wall surface coincides with the isotherm for the fuel ignition temperature. The model includes gas-phase energy transport via radiation and forced convection inside the duct and solid-phase energy transport by conduction into the fuel lining. Product gases emitted from the fire zone are assumed to mix uniformly with the ventilation gas to produce an optically dense gas mixture at the combustion temperature that enters the preheat region. Numerical solutions of the model equations for a coal-lined duct (simulated coal mine entry) have been used to investigate the effects of tube radius, air velocity, combustion temperature, and optical density of the soot-laden gas upon the terminal fire spread rate.

Jan 1, 1977

By K. D. Luxbacher

Understanding methane emissions in underground coal mines is critical for a safe and productive mine. In addition to reasonable estimation of initial coalbed reservoir parameters, it is also crucial that changes in effective stress due to mining and pore pressure reduction are taken into account due to their effects on porosity and permeability. Primary parameters for estimation of emissions or modeling of the mining environment for this purpose are porosity and permeability which can change dramatically as a result of stress redistribution associated with mining and gas desorption from a large coal volume. These parameters affect the emission rates and ventilation requirements, as well as water inflow into the working environment. Stopping leakage, on the other hand, is a secondary stress dependent factor in estimation of emissions, as convergence of the roof and floor strata, compromising the integrity of the stopping, may result in leakage, making prediction of ventilation requirements difficult. This paper aims to examine the effects of porosity and permeability changes of the coal seam on methane emissions in an underground continuous miner section. The models were developed and executed in a dynamic fashion to simulate an advancing section. Through this process, the changes of effective stress in coal, particularly their change paths, on porosity and permeability were incorporated into the models and methane emissions, concentrations, air requirements, water inflow and possible leakage from the stoppings were investigated using a conventional coalbed methane reservoir model.

Jan 1, 2009

By R. V. Lundquist

The work described in this report, part of the Bureau of Mines long-range program to develop methods of utilizing submarginal domestic sources of aluminum, was undertaken to investigate the effects of iron in the lime soda sinter process, The approximate Fe2O3 content in a sinter for maximum alumina and soda recovery was 8 to 9 percent. Fe2O3 appears to inhibit gelation, and 15.5 percent Fe2O3 produces effects similar to those produced by 1 percent sucrose. In the lime soda sinter process, aluminum silicates are sintered with limestone and soda ash to yield dicalcium silicate and sodium aluminate. The sodium aluminate is extracted by leaching in caustic solution. The solution is purified by heating in an autoclave with lime to remove silica, and alumina trihydrate is precipitated with carbon dioxide. The reactions involved in sintering and leaching are complex. A number of studies by the Bureau of Mines4-9 and others1 indicate that the iron content of sinters influenced the recovery of alumina and soda and the gelation characteristics.

Jan 1, 1962

By J. E. Pahlman

One of the goals of the Bureau of Mines is to develop metallurgical pro-cesses that conserve energy and/or that take advantage of abundant domestic energy sources. Western lignites and subbituminous coals can be used for firing pellet induration and metallization furnaces. However, the refractory linings of these furnaces must be able to withstand attack from corrosive alkali metal oxides present in the ash of many of the low-rank fossil fuels. The Bureau of Mines conducted dynamic and static slag tests on high-alumina and alumina-silica refractories to determine their resistance to lignite ash slags. The investigations showed that increased alkali content in the lignite ash caused increased corrosion and erosion of the tested refractories. The degree of corrosion decreased with increasing alumina content, with the 99-percent-alumina refractories having the highest resistance. In general, the matrix phase was attacked preferentially to the alumina grains. Also, porosity reduction and tar impregnation enhanced the corrosion and erosion resistance. The 90-to 99-percent-alumina refractories are recommended for use as furnace linings in alkali slag environments.

Jan 1, 1979

By Je M. Oh

The Bureau of Mines is conducting research to determine the high temperature oxidation resistance of substitute stainless steels (SS) containing two less strategic elements, Al and Si, instead of Cr. Chromium is considered to be a critical and strategic metal. Although the Cr content was reduced to 8 wt pct, the alloys showed better oxidation resistance than did 304 SS containing 18 wt pct Cr. Specifically, the alloys that contained Fe-8Cr-16Ni with combinations of Al and Si showed excellent oxidation resistance even at temperatures up to 1,000° C. In this study, the effects of the alloying elements on oxidation kinetics and morphology of oxides were investigated using a Cahn Rg electrobalance, scanning electron microscopy, an energy-dispersive X-ray analyzer, X-ray diffraction, and an electron microprobe. Aluminum and silicon additions in combinatin were more effective in providing oxidation resistance than either element was alone.

Jan 1, 1986

By T. A. Sullivan

Research undertaken by the Bureau of Mines in 1938 has resulted in the development of titanium from a laboratory curiosity to a commercial metal. Along with processes for producing the metal, it was necessary for the Bureau to develop methods for analyzing the metal, raw materials, and intermediate products. Some of the methods developed have been published.3 4 5/ General Services Administration (GSA) was responsible for purchasing titanium metal under Defense Production Act contracts with commercial producers. GSA designated the Federal Bureau of Mines to analyze this metal and establish its compliance with Government specifications. A substantial quantity of tin was found in some of the samples analyzed, and in July 1957 tin was added to the list of impurity elements to be determined. The specifications limited the amount of tin in titanium sponge to a maximum of 0.10 percent. A program was immediately initiated to investigate methods and techniques for determining tin in the range of 0 to 1.0 percent. A method accurate at the 0.10 percent level was necessary, as this level was the critical range for acceptance or rejection of the metal.

Jan 1, 1960

By I. L. Nichols

Laboratory characterization studies have investigated the processing variability of carbonaceous uranium-bearing materials found in-sandstone deposits. This work was conducted by the Federal Bureau of Mines in support of its goal to maintain an adequate supply of minerals to meet national economic and strategic needs. Conventional processing produces only partial uranium recovery from these ore materials. Ore samples from New Mexico, Texas, and Wyoming were examined, and each responded differently. Using direct acid leaching techniques, some of the ores required acid additions of only 50 pounds per ton, while others required 300 pounds per ton of material. Maximum extractions ranged from 83 to 94 percent in the six ores tested. Roasting those ores prior to leaching improved extraction of the uranium to the 90 to 99 percent range. An oxidative autoclave treatment used with five of these ores resulted in extraction of 78 to 97 percent of the uranium. The experimental studies also showed that some carbonaceous materials can be concentrated by froth flotation. The flotation tailings were amenable to acid leaching, and up to 98 percent of the uranium was extracted from this type of material.

Jan 1, 1979

By Kevin Connor

The Government's ban on all commercial mining operations, except for small-scale artisan exploitation of alluvial gold deposits, continued throughout 1985. Minerals produced were kaolin and lime for agricultural uses, and experimental peat harvesting for energy applications. The total value of the minerals produced during the year was estimated at $1.1 million .2 In early 1985, an agreement between the Government and Amoco International Oil Co. was ratified for a petroleum exploration concession covering 248,000 hectares of Lake Tanganyika. Onshore exploration in the Ruzizi Plain was already under way the last half of 1985. By yearend, enough seismic information was available that Amoco hoped to complete data analyses, determine onshore drilling sites, and begin drilling operations before the end of 1986. Also to begin in the latter part of 1986 were seismic studies of Lake Tanganyika. Throughout 1985, Amoco officials were negotiating with the Government of Zaire for expanding the exploration acreage into that country's portion of northern Lake Tanganyika and the Ruzizi Plain. An agreement between Amoco and Zaire could have important beneficial economic implications for both Zaire and Burundi, and onshore seismic work in Zaire logistically supported from Bujumburi could begin almost immediately.

Jan 1, 1987

By R. L. Montgomery

Heats of solution of cerium metal and cerium (III) chloride in hydrochloric acid were measured. The standard heat of formation of the aqueous cerium (III) ion at 25° C is -166.1 ± 0.3 kcal/mole. Heats of solution of cerium (III) chloride in hydrochloric acid are consistent with the existence of a complex CeC1++ having a stability constant of 1 and a heat of complexing of 5.4 kcal/mole.

Jan 1, 1962

By E. J. Kloos

Bureau of Mines-approved self-contained breathing apparatus of the compressed air demand type were evaluated for performance at low temperature. Apparatus durations, breathing resistances, and airflow rates were measured on machine tests at room temperature and -25° F. Man tests under actual wearing conditions verified the machine test results. Many serious functional changes in apparatus performance occurred at low temperature. Pressure regulators malfunctioned when diaphragms lost flexibility. Under certain conditions frozen condensed moisture sealed exhalation valves and fogged eyepieces. High-pressure leaks, not encountered at ordinary temperature, developed at low temperature. Tests results are discussed generally and specifically for each apparatus. Recommendations are given to obtain optimum performance from demand type breathing apparatus at low temperatures.

Jan 1, 1968