Search Documents

By J. G. Croeni

The titanium-iridium alloy system was investigated to determine whether alloys of this system would merit further development as control-rod material for nuclear reactors. A study was made to determine the titanium-iridium phase diagram by using melting-point, thermal analyses, X-ray diffraction, dilatometric, electrical resistivity, and metallographic techniques. The titanium-iridium alloy system was investigated between 500° and 2,400° C. Results indicate the formation of two intermetallic compounds, Ti3Ir rind TiIr3, and one intermediate solid solution centered about the 50 atomic percent iridium composition. A eutectic reaction occurs at 1,475° C, and 19 atomic percent iridium. The Ti3Ir decomposes peritectically at 1,520° C. The intermediate solid solution exhibits a maxima of 2,140° C. at 50 atomic percent iridium. This phase is also believed to undergo an order-disorder transformation at 1,750° C. Another eutectic reaction takes place at 2,000" C. and 60 atomic percent iridium. The compound TiIr3 formed at 75 atomic percent iridium decomposes peritectically at 2,115° C. Further increases in iridium content result in the formation of an iridium-rich terminal solid solution. Information obtained below 900° C. in titanium-rich alloys indicates that iridium acts as a beta stabilizer in titanium, and the authors believe that a eutectoid decomposition of beta-titanium occurs near 500° C. and 10 atomic percent iridium.

Jan 1, 1962

By G. E. Walden

The Bureau of Mines is currently engaged in a continuing investigation of the thermodynamic properties of certain inorganic compounds. As a part of this investigation, the heat contents of bismuth and cerous chlorides were measured throughout the temperature ranges of 370° to 630° K. and 370° to 1,200° K., respectively. Equations representing heat contents as a function of temperature were derived from the data by the method of least squares. These equations were used to calculate heat contents at selected temperature intervals ranging from the ice point to 650° K. for bismuth chloride and to 1,200° K. for cerous chloride; also, the heats of fusion of both compounds were calculated at their respective melting points. EXPERIMENTAL Materials The cerous chloride used in this investigation was supplied by the National Carbon Company of Cleveland, Ohio. A chemical analysis indicated Ce 56.57 percent and Cl 43.39 percent. No attempt was made to purify the compound or identify impurities since the analysis showed only about 0.04 percent total impurities. Reagent grade bismuth chloride was used without additional purification.

Jan 1, 1961

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

3. Application of Proposed Revised Standards 57.11-50 to Mines Surveyed 3.1 Subparagraph (a) 1 "Each mine shall have at least two separate and properly maintained escapeways from each working place to the surface which are so positioned that physical or environmental damage to one will not lessen the effective¬ness of the other, and which meet the requirements of travelways and man hoisting standards These escape¬ways shall reach to within 1000 feet horizontally or 300 feet vertically of each working place " 3. 1. 1 Discussion This section will deal with the 1000 and 300 feet distance requirements, Section 3. 5 will deal with the "environmental damage" provisions. During the course of the mine surveys, it became obvious that one mine's 1000 foot distance was nowhere near equal to another' s --not in the actual distance but in the time required to traverse that distance. This -Ls true for the 300-foot requirement as well. The most obvious example is that one could traverse down a 300-foot raise much faster than climbing up the same distance. The temptation is strong to recommend that the distance requirement be changed to travel times instead. However, this approach would unfortunately lead to a lot of subjective evaluations. Having a time requirement for an entire mine evacuation (Subparagraph 6) is one thing, time requirements and the requisite inspection proce¬dures for each working place are quite another.

Jan 1, 1976

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grindability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions2 issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor; if it is not, a price adjustment is made, Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1971

By J. E. Tiffany, Z. C. Gaugler

In presenting this list of permissible explosives and blasting devices , the Bureau of Mines desires to call attention to pages 16 and 23 , outlining the conditions in use under which , and only under which , the explosive or blasting device is permissible . In view of publications recounting trade practice favoring the use of a blasting device without stemming , particular emphasis is placed upon condition 4 on page lt and condition 2 on page 23 .. An explosive or a blasting device enumerated in the permissible lists of this Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming .

Dec 1, 1943

By C. B. Manula, R. L. Sanford, R. A. Rivell

A generalized flow diagram is presented in Figure 1, which shows the relationship of major model functions. This chart does not necessarily represent the anatomy of the computer program, but is designed to illustrate the informational interchange between major model functions. The related flow-charts-and computer program are listed in Parts I and II, Appendix A, respectively. Mine Car Stations The mine car stations are the activity centers for the model. The locomotive logic structure is designed to provide these stations with adequate cars and to clear them of car buildup. The model is designed to simulate a three stage haulage situation which suggests the need to differentiate station levels by type numbers. These are: a) TYPE 1 stations - mine cars are loaded here; b) TYPE 2 stations - intermediate stop and storage for mine cars; c) TYPE 3 stations - all mine cars that are stored here leave mine; and d) TYPE 4 stations - mine portal. TYPES 1, 2, and 3 have all loaded cars assigned to an ascending TYPE as their next destination. In input, if single stage haulage is designated, TYPES 1 and 3 do not exist, and if two stage haulage is called for, TYPES 2 and 3 are absent. A motor is not permitted to exchange cars between stations of the same type. Station Status Update. One major model function is to continuously evaluate the status of each mine car station. The major evaluations

Jan 1, 1974

By G. V. Sullivan

The Bureau of Mines conducted preliminary beneficiation studies of a gold-bearing graphitic schist from Blue Hill, Tallapoosa County, Ala. The average analysis of the material was 0.08 oz/ton gold. Tabling of minus 35-mesh material recovered 83 to 94 percent of the gold at grades of 6.925 to 2.165 oz/ton, respectively. A combination of jigging and tabling resulted in a concentrate assaying 24.3 oz/ton gold and contained 87 percent of the total gold. Treatment of the material by jigging, tabling, and amalgamation recovered 86.5 percent of the gold.

Jan 1, 1969

By E. V. Cilento, K. A. DiGregorio, R. C. Lantz

"An electro-optical method was used to quantify superoxide (SO) release from single rat pulmonary alveolar macrophages (PAM) exposed in vitro to respirable quartz and kaolin dusts and in vivo to quartz. Release was determined by measuring the reduction of nitroblue tdrazolium (NBT) to a diformazan precipitate at 550 nm from video-recorded images of individual cells. In vitro exposure to 0.025 or 0.05 mg/ml kaolin for 40 minutes resulted in no significant differences in either the total diformazan produced (max) or the maximum rate of diformazan production (R)./n vitro exposure to 0.025 mg/ml c1uartz decreased max 38 percent while no significant change was found using 0.05 mg/ml. However, R was decreased 31 percent and 24 percent for the low and high dose, respectively. In contrast, PAM obtained from animals exposed in vivo to quartz dust for two or four weeks in inhalation chambers exhibited increased production of diformazan. However, only PAM analyzed three days post-exposure showed significant increases, while PAM from animals sacrificed ten or 31 days post-exposure were not significantly different from control. The combined in vitro and in vivo quartz results might suggest that there is an initital acute response to exposure that decreases the ability of PAM to produce SO, followed by recruitment of production of PAM with increased SO producing capability. It appears that removal of animals from the source of exposure permits PAM to return to control levels of SO production by31 days. Whether this would be true for chronic exposure remains to be elucidated.IntroductionPulmonary alveolar macrophages (PAM) protect the lungs by phagocytizing foreign debris and bacteria.(1) This process involves ingestion as well as destruction of foreign matter. Phagocytosis usually is accompanied by a respiratory burst which increases cellular oxygen consumption leading to the release of highly reactive oxygen metabolites.(2) These agents have been implicated in the killing of bacteria by phagocytes, but they have also been shown to be toxic and,have been linked to cancer, emphysema, arthritis, diabetes, and other diseases.(3) Toxic effects may be a result of 1) an abnormally low production of metabolites, resulting in damage to lung tissue by the respired bacteria and/or dusts; or 2) an abnormally high production resulting in direct damage to lung tissue by metabolites themselves."

Mar 1, 1989

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 Rogers F. Davis

The Bureau of Mines developed a new method for the determination of oxides of nitrogen in diesel exhaust gas. The procedure, a modification of the Saltzman method, uses a NO2 absorbent for the diesel exhaust gas; the colorless absorbent becomes purple on contact with N~. When used properly this procedure gives satisfactory results in 2 hours, whereas the standard phenoldisulfonic acid method required approximately 8 hours. The new method is not satisfactory for determination of oxides of nitrogen in the overrich fuel to air ratio range.

Jan 1, 1966

By A. R. Taylor Jr.

The heat capacities of a-quartz form beryllium fluoride were measured at approximately 3° intervals from 8° to 300° K., using an adiabatic calorimeter. At 298.15° K the heat capacity and entropy were 12.39 cal/deg mole and 12.75 ±0.04 eu respectively. Enthalpy measurements were made with an ice calorimeter at approximately 30° intervals on the quartz and glassy forms of beryllium fluoride between 300° and 1,200° K. A melting point of 825° K and an 0,-8 type transition at 500° K with a heat effect of 75 ca1/mole were deter-mined from the enthalpy data for the quartz-type sample. Beryllium fluoride glass crystallized spontaneously into the quartz modification at 500° K. The heat of the reaction BeF2 (a-quartz) .... BeF2 (glass) was found to be 1,125 ±16 cal/mole at 298° K by solution calorimetry. This value, when corrected to 273° K, was used to correct for the heat absorbed by the formation of glassy BeF2 when the sample was dropped into the ice calorimeter from temperatures above the melting point. Using corrected enthalpy measurements, the heat of fusion was determined to be 1.13 kcal/mole at 825° K.

Jan 1, 1965

By G. R. Hopkins

The petroleum-refining industry established a new record in fuel efficiency at refineries in 1936, when 597,000 B. t. u. of heat were required to refine a barrel of crude oil, compared with an average of 615,000 B. t. u. in 1935 (see fig. 1). The principal factor in the "indicated gain in fuel efficiency at refineries in 1936 was an increase in crude runs of 11 percent over 1935. A large part of the heat utilized at refineries is consumed elsewhere than under stills, or in ways quite independent of crude-oil distillation. In other words, as the operating ratio (crude runs divided by capacity) for refineries increases toward the maximum of 100 percent, the fuel requirements show progressively smaller increases and the average E. t. u. consumption per barrel of crude refined declines.

Jan 1, 1938

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 Donald J. Barnes

The Glacier View RARE Ii further planning area contains no identified mineral deposits, other than stone, which cannot compete favorably with similar deposits closer to major markets. Pierce County mining claim records show six coal claims were located in the study area between 190b and 1907; however, no coal was found at the described locations. Two coal prospects, the H.O. Lamming and Floyd Rice, are within 0.5 mi (0.8 km) of the area's west boundary (fig. 1). At these prospects, impure bituminous coal beds strike approximately north and dip east toward the study area. Analyses of samples 1/ indicated an average heating value of 2,767 BTU 2/ per pound (6,436 joules per kg). Because of the low heat value, this coal is subeconomic. Intense folding and faulting which disrupted the beds would limit the use of conventional coal mining equipment, making future economic development even less likely. Trinity Resources of Houston, Texas has leased approximately 1,404 acres (568 ha) inside the study area and an additional 1,020 acres (413 ha) adjacent to the study area for oil and gas exploration. However, no oil or gas wells are known to have been drilled in or around the study area.

Jan 1, 1983

By Edward D. Thimons

The Bureau of Mines has developed a damage-resistant brattice, intended for use as a stopping in locations where blast damage to stoppings is a problem, the roof is relatively flat, and the differential pressure across the stopping is not high. Damage-resistant brattices consist of a series of vertically hung brattice panels joined to each other by Velcro connections that improve the airtightness of the brattice. When the brattice is subjected to strong blast forces, the Velcro connections peel apart, allowing the panels to open without incurring damage. The Velcro connections can then be resealed in a matter of minutes. A preliminary test in the Bureau's Safety Research Mine and subsequent long-term testing at the White Pine copper mine in Michigan and the Retsof salt mine in New York show that damage-resistant brattices withstand blasting better than conventional stoppings, while still performing as efficient air barriers when the Velcro connections are sealed.

Jan 1, 1978

By Spencer P. Howell

One of the important problems in metal mining , tunneling or quarrying is the most economical method of bringing down the ore or rock . The two factors having great influence in determining this are arilling and blasting costs . In considering the efficiency of the explosive used , the diameter of cartridge has always been supposed to play an important part . However , the Bureau's attention has been called to the lack of definite data on the effect of cartridge diameter on the strength and sensitiveness of high explosives . This information is especially valuable to the user of explosives as it assists him to determine what diameter of borehole is most economical . A paper* on "The effect of cartridge diameter on the strength and quickness of high explosives " was submitted to the sub- committee on Drills and Drill Steel of the 24th Annual Convention of the American Mining Congress by Charles S. Hurter , Technical Representative of the E. I. duPont deNemours and Co. In this paper Mr. Hurter points out that the physical characteristics of an explosive most affected by the diameter of cartridge are rate of detonation and sensitiveness to explosion by influence , and that both increase with increase in diameter . As there is a continuing tendency to the use of smaller diameter drill holes in order to lower drilling costs , and as the smaller drill hole requires a smaller diameter of explosive cartridge than larger drill holes do , this paper has been prepared to show the effect the diameter of cartridge will have on the strength and sensitiveness of the high explosives which may be used . Accordingly , the Bureau of Mines , in cooperation with the Institute of Makers of Explosives , has carried out a series of tests to show the effect of cartridge diameter on the strength and sensitiveness of certain high explosives .

Jan 1, 1923

By D. J. Bauer

A solvent-extraction system employing selective stripping of a pre loaded organic phase was investigated for recovering Sm203 from a light-group rare-earth mixture. The samarium concentrated in the organic phase, and a >99-pct-pure samarium oxide product was obtained at 76-pct recovery in a 20-stage operation using di(2-ethylhexyl) phosphoric acid (EHPA) as the organic phase. The stripping agent was a 1.5-pct hydrochloric acid solution containing 200 g NH4C1/1.

Jan 1, 1972

[In presenting this list of permissible explosives and blasting devices, the Bureau of Mines desires to call attention to pages 17 and 23, outlining the conditions in use under which, and only under which, the explosive or blasting device is permissible. In view of publications recounting trade practice favoring the use of a blasting device without stemming, particular emphasis is placed upon condition 4 on page 17 and condition 2 on page 23. An explosive or a blasting device enumerated in the permissible lists of thin Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming.]

Jan 1, 1941

In presenting this list of permissible explosives and blasting devices, the Bureau of Mines desires to call attention to pages 17 and 23, outlining the conditions in use under which, and only under which, the explosive or blasting device is permissible. In view of publications recounting trade practice favoring the use of a blasting device without stemming, particular emphasis is placed upon condition 4 on page 17 and condition 2 on page 23. An explosive or y blasting device enumerated in the permissible Lists of thin Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming.

Jan 1, 1941

By Marcia L. Harris

The National Institute for Occupational Safety and Health (NIOSH), as part of its continuing research program for evaluating coal dust explosion hazards, has investigated several areas in which current practices may need to be updated in order to adequately protect mines against coal dust propagated explosions. In the United States, current rock dusting requirements remained largely unchanged since 1969. US Title 30 Code of Federal Regulations Section 75.403 is based on a coal dust particle size survey performed in the 1920s and later was supplemented by full-scale testing of the rock dust ability to inert a coal dust explosion. NIOSH recently conducted a comprehensive survey of US underground coal mines to determine the range of coal particle sizes found in dust samples collected from the mine entries. Due to advancements in technology and modern coal mining techniques, the current coal dust particles in intake airways are significantly finer than those found in the mines in the 1920s. According to past full-scale dust explosion test results, the current rock dusting practices used in today?s mines to inert a coal dust explosion may not be adequate. Other closely related issues such as rock dust testing methods and sampling procedures are discussed.

Jan 1, 2009