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By Paul W. Johnson, Ralph C. Kirby, Frank A. Peters

Alumina can be recovered from clay , using 30 percent nitric acid for digestion . Calcined clay is crushed and then digested at 325 ° F and 85 psig pressure with less than stoichiometric nitric acid required to form normal aluminum nitrate . In this way , a solution containing both normal aluminum nitrate , Al ( NO3 ) 3 , and basic aluminum nitrate , assumed to be Al ( OH ) ( NO3 ) 2 , is formed , and in which iron is virtually insoluble . The solution is filtered and then concentrated in vacuum evaporators to crystallize normal aluminum nonahydrate . The crystals are washed with 50 percent nitric acid and then decomposed to alumina and nitrogen oxides . The design that has been developed for this process is based on published work . For a plant producing 1,000 tons of alumina a day , the estimated operating cost is $60.69 per ton of alumina , and the estimated fixed capital cost is $ 76 million using a Marshall and Stevens chemical equipment index basis of 240.0 . This process is not competitive under current economic conditions with the production of alumina from bauxite via the Bayer process . For lowering costs , future research should include study of leaching at lower temperatures under atmospheric pressure and alternate aluminum nitrate decomposition methods .

Jan 1, 1964

By Kenneth M. Earl

This report describes the results of a field study conducted by the Bureau of Mines during 1956 and 1957 on manganese-and iron-bearing mineral deposits in the southern district of Aroostook County, Maine. The work was undertaken to determine the extent of deposits largely concealed under glacial drift and to obtain subsurface samples for manganese mineral identification and research in ore dressing and extractive metallurgy. The investigation was confined to the Westford Hill-Daggett Hill area in Hodgdon Township and to the Stewart prospects and vicinity in Linneus Township. Over 50 magnetic anomalies were mapped by magnetometric surveys in the Westford Hill-Daggett Hill area, Hodgdon Township. The largest anomaly, as outlined by the 1,000-gamma contour, indicates a deposit 3,200 feet long with a maximum width of 350 feet. The smallest anomaly measures about 10 feet wide by 25 feet long.

Jan 1, 1962

By Jack L. Henry, Davis E. Traut, L. R. Penner

The Bureau of Mines conducted solvent extraction batch tests to evaluate the usefulness of neodecanoic acid ( NDA) for extracting Co 3+ from ammoniacal leach liquors high in ammonium sulfate . This work is an outgrowth of previous Bureau research in which technology was devised for the recovery of cobalt , nickel , and byproduct copper from domestic laterites . The previously devised technology uses an oxidative ammoniacal sulfate leach to treat the laterite , and nickel and copper are then recovered from the leach solution by solvent extraction and electrowinning . This report deals with the subsequent solvent extraction of cobalt from the nickel - copper raffinate solution . The results showed that about 70 pct of the contained Co 3+ can be extracted batchwise at pH 8 using NDA ( a 10 - carbon - chain highly branched carboxylic acid ) . However , NDA had a solubility of approximately 0.6 to 0.8 g / L in aqueous raffinate following extraction , and this high solubility makes it impractical for use with alkaline solutions that are low in cobalt . In addition , the extracted cobalt species ( predominately cobaltic hexammine ) is not amenable to the electrolytic recovery of cobalt metal because of its extreme stability . This fundamental prob-

Jan 1, 1965

By Jr. Hill

Laboratory metallurgical treatments of three high-iron bauxite ores from Arkansas were conducted to determine the relative effectiveness of experimental methods for recovering alumina and a commercially acceptable iron concentrate. The standard for evaluating recoveries from experimental processes was the Al2O3 recovery from Bayer digests of the crude ores; recoveries from digestion of the three ores were 74.1, 87.4, and 88.7 percent. Flotation, magnetic separation, or various combinations of digestion, calcination, and reduction-sintering, leaching, and magnetic separation of leach residues failed to produce Al2O3 recoveries as high as the standard. A high-iron-bearing fraction, containing between 68 and 78 percent of the total iron, was produced in a three-phase treatment involving a caustic, lime reduction-sinter of the crude ore, water extraction of Al2O3 from the sinter, and magnetic separation of the leach residue.

Jan 1, 1967

By J. M. Goris

The U.S. Bureau of Mines, in a cooperative project with the University of Utah, Salt Lake City, UT, and Homestake Mining Co., Lead, SD, conducted in situ monitoring and numerical modeling of rock masses supported with cable bolts in two mechanized, cut-and-fill stopes and a shaft pillar at the Homestake Mine. Extensometers were used to measure rock displacement, while cable bolt strain gauges were installed to measure loads on both conventional and birdcage cable bolt supports. These instruments provided an assessment of rock mass behavior during mining as well as essential data for verifying results from computer analyses. The numerical modeling program FLAC was used to analyze cable bolt patterns and supports. Results from the evaluation study indicated that cable bolt strain gauges and extensometers were effective instruments for monitoring the behavior of rock masses supported with cable bolts. Also, numerical modeling of the 4S-48N stope using the FIAC code provided displacement values comparable with measurements from field extensometers.

Jan 1, 1993

By G. R. Hopkins

[A new record in fuel efficiency at petroleum refineries was established in 1939, when a the average B.t.u. requirements per barrel of crude oil processed declined to a new low of 557,000 B.t.u. (see fig. 1). The average fuel requirement per barrel of crude oil refined has remained virtually stationary for the past 3 years. Thus in 1937 the average was 562,000 B.t.u., in is it rose to 567,000 B.t.u., and in 1939 it declined to 557,000 B.t.u. she largest gains in fuel economy cane a decade or so ago on the widespread introduction of heat exchanges and pipe stills. In recent years many successful innovations in heat saving have been adopted, but the combined effect of those is completely masked by the degree to which the capacity is utilized. Some heat requirements are relatively inelastic, so the average consumption per barrel of crude oil refined tends s to increase when the operating ratio (crude runs divided by capacity) declines and vice versa. In 1939 crude runs to stills increased 6 percent (from 1,165,015,000 barrels in 1938 to 1,237,840,000 in 1939) compared with a decline of about 2 percent in 1938. The operating ratio in 1939 was 82 percent compared it's 78 percent in 1938.]

Jan 1, 1941

By Lloyd A. Morley

Previous research conducted for the USBM by Penn State personnel (Grant GO-101729) found that a need existed to physically model a typical a-c/d-c coal mine section electrical system. Its purpose would be to permit preliminary evaluations of electrical problem solutions prior to launching full-scale investigations. Such use can result in greater flexibility than afforded by present computer models. Furthermore, numerous problems, which would be virtually impossible to incorporate in a computer model at this time, are more easily analyzed with physical simulation. The development of this system is now proceeding at the USBM's Bruceton Research Facilities. However, electrical specifications of scaled down components for its construction are required. This project is a result of that need and has been funded as an extension to Grant GO-133077. The following report covers these specifications. Scope of Work To represent a mined a-c/d-r. coal mine section, the typical component specifications must detail at least: a. one a-c continuous miner, b. two a-c or d-c shuttle cars, c. one a-c or d-c roof bolter, d. one a-c section fan, and e. feeder cables. Further, each machine should be portrayed by each of its general

Jan 1, 1974

By N. Kyriazi

A performance study of oxygen self-rescuers from the United States and other countries was undertaken as an assessment of present worldwide technology. The apparatus were tested a an breathing and metabolic simulator in the Life Support laboratories of the Bureau of Mines. Parameters monitored during the testing were inhaled levels of C02 and 02, inhaled gas temperature, and breathing resistance. The metabolic demand placed on the apparatus represented the average demand of the 50th percentile miner performing a 60- min man-test 4, as described in 30 CFR 11H. Results presented include ;apparatus service life and subjective comments as well as averages and peaks of monitored parameters.

Jan 1, 1984

By W. E. Cooper

The International Intercalibration and Intercomparison Program (HIP), consisting of several selected laboratories from four countries, held a radon progeny intercomparison measurement at the U.S. Bureau of Mines experimental Twilight Mine on September 12-14, 1988. Grab samples were taken at four different conditions of low and high radon progeny and condensation nuclei concentrations, respectively. The results showed good agreement among all seven participants. The coefficient of variation of all measurements was 4.7%; after minor corrections for flows and some systematic biases, it was reduced to 3.2%.

Jan 1, 1990

By Clarence O. Babcock

In this report, the Bureau of Mines presents a method for reducing the complexity of designing room-and-pillar mining systems by treating them as anisotropic soft inclusions in the surrounding ore or host rock. Theoretical models were derived for the calculation of the effective Young's moduli for these systems. The predicted behavior of the plate-type elements used in these models agreed well with test results from 21 plates each with 49 holes spaced on a 7 X 7 Cartesian grid. The plates behaved as anisotropic solids, the effective Young's moduli of which could be predicted from the scaled hole size and spacing. Actual hole shape was insignificant. The effective Young's moduli for simple mining systems are calculated in sample problems. This approach should provide information about field stress in the mining region and the stress distribution in the surrounding ore or host rock when the actual mining configuration is replaced by an anisotropic inclusion in a finite element analysis. The field stress within the inclusion can then be applied to the actual opening shape to determine the stress distribution within the mining region.

Jan 1, 1970

By R. C. Corey

GERMANIUM is an element that has come into widespread use in the electronics industry in recent, years. So far this increasing demand has been, met by ample supply: however, the future balance is uncertain, and the need has been recognized to discover additional domestic sources of germanium. This investigation was conducted to study the possibility of obtaining a potential supply of germanium from coal or coal ash. It has been known for some time that coal contains germanium; the discovery that By ash from coal-fired boilers often contains appreciably more germanium than the original coal suggested the possibility that coal ash might be an abundant and economical source of this element. In this study the concentration of germanium was determined in numerous samples of coal and ash. A number of miscellaneous waste materials also were examined in the course of the investigation; the results are reported as a matter of general interest. The methods and equipment employed are discussed in detail. Sample-preparation and analytical techniques are described in the appendix. Spectrographic analyses were made on a total of 639 samples, including coal, coal ash, slap ash from lignite and peat, wood ash, and various inorganic materials. Qualitative analyses were run on all samples, and quantitative determinations were made on those samples that contained enough germanium to be measured by this method The lower limit at which germanium can be determined quantitatively by spectrographic analysis is 50 parts per million (p. p. m.), but concentrations of less than 20 p. p. m. can be detected qualitatively.

Jan 1, 1959

By Wallace W. Roepke

The Bureau of Mines determined coal-cutting forces and primary dust generation of four styles of radial gage bits as used on end rings of continuous mining machines. Direct comparisons for reference were made with two widely used conical plumb-bob types having 60' and 90' (nominal) included tip angles. The cutting forces for all of the gage bits were similar to those of the 60°-tip plumb-bob bit. All bits except the RAD-3 gage bit generated similar amounts of primary total dust at shallow cutting, but during deeper cutting, the amounts varied and the gage bits produced as much as 2-1/2 times the dust produced by the 60° bit. This seems atypical since past experience has always shown differences in dust generation at shallow cutting. The specific energy was more like that found previously with other bits, since the values were spread at shallow cutting but became nearly similar at deeper cuts. The 90° bit and the RAD-3 gage bit are not recommended for use except in extremely difficult cutting conditions where dust and forces are of secondary importance. The choice among the remaining four bits can be made on the basis of dust, energy, forces, or cost, as circumstances dictate.

Jan 1, 1983

By M. L. Glenn

The Bureau of Mines is conducting research on Fe-based alloys using Si and Al additions to reduce the Cr required for heat-resisting appli-cations. Part of this research is being done to evaluate alloys containing (8-10)Cr-(10-14)Ni-(0-8.5)Si-(0-4) Al to determine which of these alloys have austenitic structures, as well as fabrication properties and oxidation resistance sufficient to substitute for type 304 stainless steel. Based on initial results, an Fe-lOCr-11Ni-5Si alloy and an Fe-8Cr-13Ni-5Si alloy were selected for evaluation of oxidati.on, stress rupture, and tensile properties. Both alloys have oxidation resistance at 7000 and 8000 C that is better than that of type 304 stainless steel. The stress rupture strengths are less than that of type 304 stainless steel but significantly better than that of commercial heat-resisting steels with similar Cr contents. Yield strengths of the alloys were equivalent to that of type 304. Both alloys had high tensile strengths comparable to those of stainless steels that transform to martensite during straining (e.g., type 301). These alloys have weld-hot-cracking resistance comparable to that of type 304 stainless steel. This initial study shows that Si has potential as a substitute for Cr in stainless steels for heat-resisting applications.

Jan 1, 1984

By F. E. Armstrong

This report describes development and application by the Bureau of Mines of techniques and instruments for using radioactive inert-gas tracers to determine flow paths through petroleum reservoirs that have natural fracture systems and for which water injection has been selected as the stimulative production method. A field test was made to prove the techniques and evaluate instrumentation. The feasibility of applying the techniques and instruments to the solution of reservoir problems in other stimulative methods of production also is discussed. Oil commonly is displaced from sandstone host rocks by the action of a driving force that causes the oil to move through interstices of the rock and into production wells. In addition to the requirements of oil being trapped within the sand pores and the presence of an effective displacement mechanism, the rock itself must have adequate permeability to permit flow of oil and other fluids.

Jan 1, 1961

By BUREAU OF MINES

PLATINUM

Feb 1, 1922

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 G. W. Birge

This report describes the carbonizing properties of the principal coal beds of McDowell County, W. Va. Coals from 14 coal beds were selected for study: Upper Cedar Grove, Middle Cedar Grove, Lower Cedar Grove, Eagle, Douglas, Iaeger, Sewell, Welch, Beckley, Fire Creek and Pocahontas Nos. 3, 4, 5, and 9. Selection was based upon estimated minable reserves. McDowell County coals rank either as high-volatile A, medium-volatile, or low-volatile bituminous coal, and this variation in rank is reflected in the wide diversity of the carbonization properties of the coals. All coals tested were either satisfactory as mined or could be upgraded to meet present chemical standards for metallurgical coke; the coals produced strong coke, as determined by ASTM shatter and tumbler tests.

Jan 1, 1958

By Martin Hertzberg

A comprehensive study of the flammability behavior of air-dispersed coal dust was made using an 8-liter Bureau of Mines system which included the following: (1) An optical probe to continuously monitor the dust concentration; (2) measurements of ignition energy requirements; (3) the use of several narrow size distributions ranging from 3 to 65 µm in average diameter; (4) measurements of the extent of flame propagation based on pressure attained at constant volume, residual O2 content after combustion, and flame and dust surface temperatures. The measured lean limit for near-horizontal propagation of Pittsburgh coal dust was about 135 mg/l (milligrams per liter), virtually independent of particle size. Required ignition energies were hundreds of joules and measured limit flame temperatures were 1,450 to 1,600° K. Data on inerting? requirements with KHC03, rock dust, and NaC1 gave approximately the same results as full-scale explosion tests. The good agreement suggests that the cause of earlier discrepancies between small-scale laboratory data and full-scale mine experiments may not have been the difference in size, but were rather a problem of proper care in isolating and controlling the significant experimental variables and in consistently defining the extent of flame propagation at the limits.

Jan 1, 1979

By Robert H. Peters

This report presents findings from a Bureau of Mines study on barriers that may prevent miners from correcting and avoiding groundfall hazards. Such barriers stem from four basic types of problems: (1) inability to recognize groundfall hazards, (2) inability to correct groundfall hazards, (3) lack of motivation to search for groundfall hazards, and (4) lack of motivation to correct groundfall hazards. Data are presented that summarize the views of miners, section supervisors, and mine inspectors about the contribution of these barriers to groundfall accidents and what they think should be done to reduce the frequency of injuries sustained by falls of roof and rib. The report also includes a summary of miners' responses concerning their recent experiences with groundfall accidents, along with industrywide statistics on accidents and injuries caused by ground falls in underground coal mines.

Jan 1, 1987

By D. A. Reynolds, C. R. Holmes

The Bureau of Mines - American Gas Association ( EM - AGA) carbonization test has been used to determine the carbonizing properties of 66 American coals and a larger number of coal blends . A summary of the results obtained for the first 30 coals , including 6 blends , has been published ,4/ and results for individual coals have been reported as the investigations were completed . A bibliography of all publications pertaining to this work has been issued recently . Many of the coals were carbonized at 800 ° and 900° C. in two sizes of retorts ( 13- and 18 - inch diameters ) ; and , because the quality of coke is affected by changing the size of the retort , this report has been prepared to show the average physical properties of coke from the two sizes . This report also purposes to extend the correlation of the physical properties of coke with the rank of coal made by Fieldner and Davis in their summary of the EM-AGA tests on the first 30 coals .

Jun 1, 1942