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By James S. Browning

The purpose of this investigation was to develop a dependable and economic method for recovering spodumene and mica from pegmatites of the type found in Gaston County, N. C. Laboratory batch tests and continuous flotation tests were made by the Federal Bureau of Mines to determine the feasibility of treating the ore by flotation to recover high-grade spodumene and mica concentrates. The spodumene flotation circuit yielded concentrates containing 6.50 percent lithia (Li20), with an overall recovery of 81.8 percent of the lithia in the ore, The mica circuit yielded concentrates containing 97.5 percent mica, with a recovery of 82.5 percent of the mica in the spodumene tailing.

Jan 1, 1961

By L. C. IlsLey, E. J. Gleim

The extensive use of pulverized coal for fuel in industrial plants has brought to the front again a question that heretofore has been considered only a mining problem, namely, " Can coal dust be ignited by an electric arc ? " If it can be so imited, the next logical query is , "under what conditions can such ignition occur ? " In view of the new problems relating to pulverized coal installations , and because of occasional mine disasters attributed to ignition of coal dust by electric arcs , it seems advisable to review the work done by Thornton and Bowden with electric flashes in coal dust , and to report two preliminary investigations conducted by the Bureau of Mines .

Jun 1, 1922

By Richard W. Watson

Card-gap and projectile impact sensitivity data are presented for a wide variety of explosive compositions tested at the Bureau of Mines in more or less standard test geometries. The results of both tests are in good agreement in that they provide the same sensitivity ordering for different subclasses of explosives. Least sensitive were homogeneous liquids that did not exhibit a tendency to undergo low-velocity detonation, ammonium nitrate-fuel oil, and most cast military explosives. Of intermediate sensitivity were pressed and powdered military explosives, cast pentolite, permissible and non- permissible water-based explosives, and one commercial two-component explosive. The most sensitive were permissible and nonpermissible dynamites and explosives susceptible to low-velocity detonation.

Jan 1, 1973

By H. C. Carpenter

Data are presented comparing results obtained with 17 different catalysts in hydrogenating crude shale oil to gasoline in single-pass operation. A method is described for predicting the maximum yield of gasoline obtainable at constant pressure for each catalyst from results of a limited number of experiments at different temperatures. Operating variables have considerable influence on yields and properties of products. With most of the catalysts, at operating temperatures below 890° F. liquid yield exceeded 100 volume-percent. Above this temperature the volume of liquid product decreased rapidly. Maximum gasoline production in most instances was achieved at a temperature higher than that at which the maximum volume of liquid product was produced.

Jan 1, 1959

By D. A. Reynolds

The Bureau of Mines-American Gas Association survey of the carbonizing properties of American coals was begun in 1929, and has been continued almost without interruption since that time. Upwards of 100 coals have been carbonized at low, medium, and high temperatures in this survey, and about 200 additional coals have been carbonized at high temperatures only. All survey coals were blended with coal of different rank for carbonization at one high temperature (900° C,). During the past few years, 12-high-volatile A coals were blended with Pocahontas No 3 coal from Kimball, McDowell County, W. Va., and in this report the physical properties of the cokes from these high-volatile coals and their blends are compared.

Jan 1, 1949

By H. L. Burmeister

These properties were examined by a Bureau of Mines engineer in 1949. During 1950, these mines were studied by the Bureau to determine the possibility of increasing the production and augmenting the supply of fluorspar. As a result of this study, it was decided to core-drill the Knox-Yingling vein to test the continuation of fluorspar to a greater depth than that reached by mine workings. It also was desired to relate the present deposit with the Rosiclare formation. Development work by the Bureau of Mines was performed from February to May inclusive in 1951. Four diamond-drill holes aggregating 2,733 feet were drilled in the hanging wall of the vein.

Jan 1, 1952

By L. B. Pankratz

The heat contents of the sesquioxides of erbium, holmium, thulium, and ytterbium (Er203, Ho203, Tm203, and Yb203) in the cubic crystalline form were measured over the temperature range from 298° to 1,800° K. The erbium and holmium sesquioxides gave regular heat content-temperature curves. Thulium sesquioxide had a minor thermal anomaly near 1,680° K, with a heat absorption of 310 cal/mole; similarly, ytterbium sesquioxide had a minor anomaly near 1,365° K, with a heat absorption of 150 cal/mole. The heat content results are presented in both tabular form (at 100° intervals) and in algebraic form. Entropy increments, corresponding to the tabulated heat content results, also are listed.

Jan 1, 1963

By A. J. Kraemer

This report on the physical and chemical properties of crude oils of California is one of a series on the producing districts of the United States. It includes a short discussion of results, tabulated data, and individual analyses of California crudes. Analyses of crude oils from the fields of Fresno, Kern, Los Angeles, Orange, and Ventura Counties have been published in Serials 25952 and 26083. The analyses reported in this paper corer samples that were obtained subsequent to the publication of Serials 2535 and 2608. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting of samples was facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1927

By A. C. Johnson

The Ellington manganese deposit in Reynolds County J Mo., had been known for some time; and limited exploration, consisting of test pitting and sinking a shaft 54 feet deep on the property, had been done by private interests. Late in 1941, the Bureau of Mines cleaned, deepened, and sampled many of the existing pits and dug and sampled 27 new ones. The shaft was unwatered and sampled, and several pockets of manganese ore were trenched to determine their extent. Samples were analyzed and beneficiation tests on 1 ton of the ore were made at the Rolla, Mo., station of the Bureau of 'Mines. Results of the investigation indicated that the deposit was small and low in manganese content.

Jan 1, 1948

By J. W. Paul

The tests described herein were made in the course of a series of experiments on coal-mine ventilation factors which the Bureau of Mines has beep; conducting for the past two years at its experimental mine near Bruceton, Pa. The object of the present tests was to determine the leakage of two air locks which had been placed in the experimental mine as hart of the equipment for tests on friction factors. Position of the Doors. The first or inner lock gas across the aircourse between No. 1 and No. 2 left butt entries, and forced the air through these butts. An air-measuring suction in No. 1 butt determined tae volume passing at tent point.

Jan 1, 1924

To provide a simple means for rapidly checking methane concentrations at working faces in coal mines while remaining under permanently supported roof. The Approach: A light telescopic probe, through which a gas sample can be pumped Into a methanometer, has been developed. See Figure 1 [ ] How It Works: The telescopic probe consists of sections of small stainless steel tubing encased in sections of lightweight fiberglass tubing. When fully extended the probe is almost 19 ft. long; fully closed it is approximately 5-1/2 feet long. It can be used In either of these positions as well as at intermediate extensions. An approved methanometer is clamped to the probe by a support bracket.

Jan 1, 1975

By David R. Forshey

This Bureau of Mines report presents a quantitative theoretical analysis of a coupled gasdynamics-heat release system involving the kinetics of water condensation in and behind the rarefaction wave in a shock tube using the method of characteristics. The merger of characteristics to form a shock wave is included.

Jan 1, 1977

By H. Robert Ensminger

The Belizean economy registered a modest real growth of 1.3% during 1981. The gross domestic product (GDP), based on current prim was $121 million' with an inflation-rate of 10%. The country received $19 million in economic aid during 1981. In early 1981, Belize'e four commercial banks raised the interest on deposits to 15% in an effort to curb capital outflow. During 1981, the financial situation deteriorated somewhat, particularly the balance of payments. For the year the total value of imports exceeded exports by almost $38 million, while the Government continued to maintain a fairly free trade policy. Import duties and term averaged about 8% on essential item and 40% on nonessential ones.

Jan 1, 1983

By Elaine T. Cullen, Thomas W. Camm

The mentor/learner model is a time-honored approach to teaching, including within the mining industry. Miners know when they see excellence and have a deep respect for experts in their field. By using expert miners as mentors to other, less-experienced miners, training programs can be developed that will have a legitimacy and credibility that resonates with those being trained. Building upon concepts in current theories of adult education, this paper highlights the unique advantages of using mentoring as a teaching method that can make the educational experience both interesting and effective. Current NIOSH safety training materials use these concepts to deliver effective adult learning experiences for workers in the mining industry.

Jan 1, 2002

By Michael Sokaski

The Cliff Springs prospect in the northern part of the Slate Range Wilderness Study Area (WSA) contains only minor amounts of gold and silver. Clay near this prospect contains insufficient aluminum to be of economic interest, although alunite claims are recorded in the vicinity. Mineralized rock at the Crescent Mine adjacent to the WSA contains gold, silver and lead occurrences. The host rock may be present in the extreme southwestern part of the WSA, which is covered by alluvium. Substantial sand and gravel deposits are present but these occurrences are remote from markets. Much of the USA is underlain by volcanic rocks and alluvium and consequently the mineral resource potential there remains unknown.

Jan 1, 1983

To predict the spontaneous combustion potential of bituminous coals using a simple expression based on an easily acquired coal property. Background Approximately 20% of underground coal mine fires in the United States since 1978 have been attributed to spontaneous combustion. Spontaneous combustion fires in underground mines are most likely to occur in gob area; and are difficult to detect and to extinguish by direct fire fighting methods. Often, sections of the mine or the entire mine must be sealed for long periods, at a great economic loss to the mine operator, mine employees, and the surrounding community. It is conservatively estimated that the cost of scaling a large mine is about $50 million.

Jan 1, 1989

By Wilbert J. Huff

The Explosives Division of the United States Bureau of Mines makes certain laboratory and field investigations that deal with explosions, explosives, ignition, and combustion, together with many related problems, such as the cause and prevention of fires, and certain fundamental scientific questions bearing upon the determination of the chemical and physical mechanisms underlying some of the important phenomena encountered. Its work on explosives has been particularly directed toward determination of the chemical and physical characteristics of explosives designed for use in coal mines and in a more limited way to those used in metal mines, tunnels, quarries, and other engineering operations. This testing is handled by two units of the Explosives Division, as follows:

Jan 1, 1937

By John K. Owens, Wayne L. Howie

Mobile roof support (MRS) machines are used as roof support during pillar recovery in retreat operations in lieu of wooden posts, cribs, or hydraulic props. A Mine Safety and Health Administration-permissible load rate monitoring system was developed for the MRS by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. The system uses a dedicated embedded processor to monitor changes in pressure inside the hydraulic cylinders of the MRS through multiplexed data acquisition channels and converts these pressure changes to load rates that sequentially activate three load-rate-indicator lights mounted on the machine. Each light represents a different loading rate to alert mine personnel to dangerous conditions during pillar extraction.

By R. R. Backer

The Bureau of Mines, in cooperation with Washington Irrigation and Development Co. (WIDCO), evaluated the dewatering of fine coal-refuse slurry using chemicals and various types and combinations of drains in natural earth impoundments. About 40 lb of lime and 2 lb of polymer per ton of dry solids were mixed with the underflow from the preparation-plant thickener. Clear, free water was immediately liberated from the slurry. The percent solids by weight of the slurry increased from about 17 to 30 immediately, and after 5 days increased to 45 wt-pct. This indicates a threefold reduction in total volume after 5 days from 172 cu ft/ton solids originally to 56 cu ft/ton solids.

Jan 1, 1981

By Wilbert J. Huff

The Explosives Division of the United States Bureau of Mines makes certain laboratory and field investigations that deal with explosions, explosives, ignition, and combustion, together with many related problems, such as the cause and prevention of fires, and certain fundamental scientific questions bearing upon the determination of the chemical and physical mechanisms underlying some of the important phenomena encountered. Its work on explosives has been particularly directed toward determination of the chemical and physical characteristics of explosives designed for use in coal mines and in a more limited way to those used in metal mines, tunnels, quarries, and other engineering operations. This testing is handled by two units of the Explosives Division, as follows:

Jan 1, 1937