Search Documents

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 Robert M. Doerr

The purpose of the investigation was to determine the oxidation behavior of selected tungsten-cobalt alloys. Specimens of Wand W-Co containing 0.7, 1.7, 3.4, and 9.7 weight-percent Co were subjected to pure 02 at 1,000° and 1,100° K, and specimens of W-Co containing 29.8 weight-percent Co, at 1,100° K. Reaction kinetics were determined volumetrically. For specimens other than those containing 29.8 percent Co, the reactions proceeded at about a constant rate at either temperature, indicating the formation of a scale of constant protectivity; the reaction rates were essentially independent of the Co concentration. The scales on these alloy specimens consisted principally of WO3 and CoWO4. Specimens of a 29.8 weight-percent Co alloy, consisting primarily of the W6CO7 phase, oxidized with only slight deviations from the parabolic rate law at 1,100° K. The protective scale on these specimens consisted chiefly of Co3O4, CoW04, and W1 8°49; Co3O4 was outermost, and the W18O49 was adjacent to the alloy. The results suggest that the Co-rich outer scale inhibited the inward transport of 0 to an extent sufficient to greatly limit the amount of the nonprotective WO3 formed, so that protective W18O49 formed instead.

Jan 1, 1967

By R. E. Coleman

The molecular species occurring at the mineral-reagent interface of the galena-aqueous potassium ethyl xanthate system was studied by developing a technique for using an attenuated reflection method in conjunction with standard infrared spectroscopy procedures. Lead ethyl xanthate was detected from the infrared spectra of all galena surfaces treated in the pH range of 7 to 11. At pH 8.5, lead ethyl xanthate formed as a film chemically bonded to the galena surface. A solvent extraction sampling method was employed with infrared spectroscopy to obtain quantitative data on the lead ethyl xanthate removed from the galena surface. The data showed that between pH 7 and 11 thy quantity of lead ethyl xanthate physically adsorbed decreased as the pH was decreased; in the same pH range, the quantity of free lad ethyl xanthate in the aqueous medium remained constant, and the amount of unreacted xanthate varied.

Jan 1, 1966

By D. Harrington

Approximately 6,000 coal mines are operated in the United States. All of them have in some degree the elements that are likely to contribute to an explosion, hence it is surprising that explosion disasters are not more frequent and that many mines have been operated for years and finally worked out and abandoned without experiencing an explosion. The absence of coal-mine explosions does not always indicate that effective efforts have been made to prevent them but rather that the nine has been fortunate in that the combination of circumstances necessary to cause an explosion has not existed. In view of present knowledge of the methods of preventing explosions, disasters are inexcusable and discredit the mining industry. The methods of preventing mine explosions are known to experienced, well-informed persons engaged in coal mining, yet despite this knowledge far to many coal-mine operators continue to use practices and methods that they should know have resulted in numerous explosions. Moreover, many mine workers persist in following past procedure irrespective of consequences and in breaking safety rules or indulging in practices almost certain eventually to result in disaster. Continued failure to apply known common-sense methods of accident and explosion prevention unquestionably will cell for ultimate enforcement of law.

Jan 1, 1940

By F. S. Crawford

Safety devices and guards are often looked upon as the last word in safety by the men around the shop or large industrial plant . However , thorough knowledge of the details of their jobs and of the dangers attending them are even more important . It should be unnecessary for all men to go through the experience of the first man to meet an unknown danger , but that appears to be about the only way by which many learn . Practically every danger connected with the job around a mine , blast furnace , steel mill , foundry , coke oven , cement mill , or other operation , was encountered for the first time by someone , and if he was fairly fortunate he either got hurt or just missed being injured and lived to tell his " budaies " how it happened; he spread the knowledge of that particular danger . Sometimes , but not often , a man can foresee a danger . If he could always be on guard and remember everything he had ever learned and also know everything that had happened to the other fellow , and then let that knowledge keep him aware of the dangers in his own immediate " job , " so that he would work the safe way for both himself and the other fellow , he would have what safety engineers call " safety consciousness . " Being safety conscious is a fine attribute , as it really means knowing all about one's job . A man who is really safety conscious is one of the best and most efficient workmen in the whole plant . The boss wants men of that kindmen who want to learn and who try to learn every little detail about their jobwhere there is danger of spoiling the heat or getting burned by hot metal in a steel plant or of loading rock instead of coal or ore in a mine . Such men know how to do whatever job they are on easily and with the least amount of hard work and at the same time get it done as quickly as possible with safety . A man who is safety conscious has to nearly all intents and purposes developed eyes in the back of his head , if he is in a big mill where there if something going on all around him . These eyes are not real eyes , but they are what might be termed a sixth sense which he has developed by his experience in the mill as well as in other dangerous work which he may have done before in other plants . There may be occasions when a man's safety consciousness will leave him for just a short time ; this is likely to happen when he is thinking about a quarrel he had with his wife which has not been cleared up happily , or perhaps when he has bought too many things on installment and with sickness at home

Apr 1, 1931

By M. D. Carver

The purpose of this investigation was to determine the effects of variations in content (near the residual level) of the impurities aluminum, nitrogen, manganese, and copper on the corrosion rate in pressurized hot water and in pressurized steam of zircaloy-3, a zirconium-base alloy of 0.25 percent tin and 0.25 percent iron. Thirty-five 10-pound ingots were cast with the appropriate additions of impurity elements, and these were converted to wrought sheets. These specimens were then tested both in water and in steam. The analysis of the resulting data showed that in environments of either pressurized hot water or superheated steam, corrosion rates increased with increasing content of aluminum, nitrogen, or manganese, but were not affected by variations of copper. The effects of aluminum and nitrogen were found to be greater than the effect of manganese. INTRODUCTION At the request of the Atomic Energy Commission (AEC) in August 1956, the Federal Bureau of Mines, in cooperation with Bettis Plant of Westinghouse Electric Corp., began investigating the effects of certain impurity elements on the corrosion rates of zircaloy-3 in pressurized hot water and in pressurized steam. It was necessary to know these effects in order to set control limits on residual impurity levels in zirnaloy-3, intended for heat transfer service in the nuclear reactor of the pressurized water type. A factorial expert it was designed by Westinghouse statisticians. The Atomic Energy Commission provided raw zirconium sponge purchased from Wah Chang Corp. The Bureau's laboratory at Albany, Oreg., made material of different combinations of impurity levels and subjected the material to corrosion tests. This report will describe the work done at the Bureau laboratory and will show, quantitatively the effects of different residual levels of aluminum or nitrogen, or manganese or copper on corrosion rates.

Jan 1, 1961

By Frank E. Cash

The information in this report covers the accident experience of the pebble-phosphate industry of Florida for 1935 and 1936, as well as the 5 years 1930-34, inclusive, statistics of which were published in Information Circular 69174/. The compilation and publication of such accident experience statistics enable the pebble-phosphate industry, as well as other industries, to consider relative hazards and to compare experience and thereby promote accident prevention.

Jan 1, 1937

By Leon W. Dupuy

"INTRODUCTION Scheelite occurring in tactite at the Black Rock tungsten mine, near Benton in Mono County, Calif., was investigated by the Bureau of Mines in cooperation with the Geological Survey as part of their search for additional sources of supply of strategic minerals authorized under the Strategic Materials Act. 3/4/The work accomplished by the Bureau, and the assays of samples taken are described in this manuscript. The ore found aided materially in prolonging the operating life of the mine during the recent national emergency, supplying much-needed tungsten for war use. ACKNOWLEDGMENTSIn its program of investigations of mineral deposits, the Bureau of Mines has as its primary objective the more efficient utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. The Mining Division, under the direction of Lowell B. Moon, chief, conducts preliminary examinations, performs the actual development work, and prepares the final report. The Metallurgical Division, under the direction of C. C. Ralston, chief, analyzes samples and performs beneficiatibn tests."

Mar 1, 1948

By Oliver Bowles

Granites are classed as igneous rooks; they have been formed by the solidification of rook magmas or Solutions from deep within the earth. It is an almost invariable law of nature that mamas which cool quickly form fine-brained or glassy rocks, while those that cool slowly are completely crystallized and are coarser-grained. Granites, being of the latter class, are regarded as having attained their solid form at considerable depth below the surface under conditions of high temperature and pressure. The constituent minerals crystallized out slowly, the crystals interlocking with one another. The great depth of overlying rocks that must have been present when crystallization took place has been removed by erosion over large areas on the surface of the earth in consequence of which granites appear at or near the surface in many localities.

Jan 1, 1930

By T. Estelle Gardner

Heat-capacity measurements were made over the range 8° to 350° K on beryllium sulfate dihydrate and beryllium sulfate tetrahydrate using an adiabatic calorimeter. No anomalies were noted in the curve for either compound. Smooth values of heat capacity, entropy, enthalpy function, and free-energy function were calculated from the heat-capacity data at 10° K intervals and at 273.15° and 298.15° K. The entropy values calculated at 298.15° K were 39.01 ± 0.12 entropy units (eu) for the dihydrate and 55.68 ± 0.17 eu for the tetrahydrate.

Jan 1, 1967

By R. G. Meara, O&apos

[P.F? bmit e-ninirq ir.3.l r;tq: in the Znited State :; was u~irlyortant p~ior to the Torld ;Jar, ?-.lt with the c~r,sxti~rl of imports d11rln.c thr World 'Jar tke Rmericnn mar~factu~er:. of 1itkopone mcl Sayiun c;~oai?als forced tile tl~veloor?.ent of domertic bar,i$e dqosit9. Pr%~~,n-ily bcca-lse of tho increasing dc.n;;nl'i for lit,hupone3 by the pr?i:~t, Tlocr-covcrin~;, ,md rt1tbe.r indl~stries, ~3c.vs1o~:rnc2t of cto~entic de~onits has cr~ntim~ed to c-cpand. 13 1914, the salnr! oC doxegtic c~l~.dt? t,m-it~ ;u~cr-~nteii. to 52,91? tons, in 1237 ???,1!.1 tons nmre so1.d; thc 12:t~r rcyrprcntcd 77 .E;T pmccnt of the tot,:rl, dr??;ectic and imortcd., haritd US~C in the Cnited State? di7rinz t,hat :.vXr. C,f +he total 193,3:& ton? coy.1~-ed in the United 4 Steter ir. 135, 3E.X percent v;as usec? as groi.z.ld ~rai.te? , "0.3 percent arr lithopone, and 17 .:A ].ercc?t in the rnx 11fact,ure of b;~riim chs:nicals ]

Jan 1, 1938

By R. G. Meara, O&apos

[P.F? bmit e-ninirq ir.3.l r;tq: in the Znited State :; was u~irlyortant p~ior to the Torld ;Jar, ?-.lt with the c~r,sxti~rl of imports d11rln.c thr World 'Jar tke Rmericnn mar~factu~er:. of 1itkopone mcl Sayiun c;~oai?als forced tile tl~veloor?.ent of domertic bar,i$e dqosit9. Pr%~~,n-ily bcca-lse of tho increasing dc.n;;nl'i for lit,hupone3 by the pr?i:~t, Tlocr-covcrin~;, ,md rt1tbe.r indl~stries, ~3c.vs1o~:rnc2t of cto~entic de~onits has cr~ntim~ed to c-cpand. 13 1914, the salnr! oC doxegtic c~l~.dt? t,m-it~ ;u~cr-~nteii. to 52,91? tons, in 1237 ???,1!.1 tons nmre so1.d; thc 12:t~r rcyrprcntcd 77 .E;T pmccnt of the tot,:rl, dr??;ectic and imortcd., haritd US~C in the Cnited State? di7rinz t,hat :.vXr. C,f +he total 193,3:& ton? coy.1~-ed in the United 4 Steter ir. 135, 3E.X percent v;as usec? as groi.z.ld ~rai.te? , "0.3 percent arr lithopone, and 17 .:A ].ercc?t in the rnx 11fact,ure of b;~riim chs:nicals . ]

Jan 1, 1938

By G. R. Strimbeck

The Federal Bureau of Mines has been developing processes for producing synthesis gas directly from coal, oxygen, and superheated steam. An atmospheric-pressure pilot plant was constructed and operated to: 1. Determine the operability of the plant for gasifying coals of different ranks under various operating conditions. Listed in decreasing order of rank, these coals included a Pennsylvania anthracite, a bituminous A coal from the Sewickley bed, West Virginia, and a subbituminous C coal mined in the Lake de Smet region of Wyoming. 2. Determine the effect of varying operating conditions on: (a) Standard cubic feet (std.c.f.) of oxygen and pounds of coal of different rank required to make M std.c.f. of product gas (carbon monoxide plus hydrogen); (b) carbon gasified, percent; (c) exit-gas temperature, degrees F.; and (d) heat loss, B.t.u. per pound coal. 3. Compare the gasification characteristics, indicated in item 2, of coals of different rank: Bituminous A, anthracite, and subbiturninous C. 4. Determine the concentration of dust in the gases produced and the efficiency of dust removal, and investigate the relation between the sulfur content in the coals gasified and the gases produced.

Jan 1, 1960

By C. C. Knox

In Kiowa County, Okla., extensive deposits of clay are closely associated with pre-Cambrian anorthosites and gabbros. Investigation by the Bureau of Mines, including 1,723 feet of auger drilling, has shown the presence of very large quantities of clay containing between 20 and 25 percent alumina. All of the material contains large amounts of impurities, and even the best clays, selected for their relatively low content of iron, titanium, and magnesium, are unsuitable for the production of alumina by the sulfuric-acid process The soda-lime process gave somewhat better results, the product being nearer specification for commercial alumina. The clays are not amenable to beneficiation by simple sedimentation processes, and the alumina content could not easily be increased to produce material suitable for any alumina process.

Jan 1, 1948

By F. E. Armstrong

A program with the objective of developing a fast, accurate instrumental method of analyzing mine dust for incombustible content has been underway in the Bureau of Mines for several years. Several prototype instruments making use of a gamma-ray backscatter technique have resulted. Although extensive laboratory testing has shown that these instruments are accurate under laboratory conditions, only extensive field testing will prove their ultimate practicality and usefulness. This report shows that under most conditions these devices are at least as accurate as the volumetric method and much faster in use. Other data obtained during the same study concerning mine dust are presented; these concern moisture content, sample bulk density distribution, and some particle size distribution information.

Jan 1, 1973

By Glen C. Reed

"The Avon mica district of Latah County, Idaho, is situated on a heavily forested spur of the Thatuna Range at an average altitude of 4,000 feet. The nearest rail connection is at Avon, a small farming settlement 7 miles to the south. The main supply point is Moscow, Idaho, which is 35 miles by graveled and graded county roads from Avon.Discovery of mica-bearing pegmatites in 1885 was followed in 1888 by exploitation of several outcrop deposits. Although factual data are unavailable, past production appears to have been well in excess of $100,000. Recent production (September 191 to April 1945) amounted to 65,824.78 pounds of trimmed sheet mica and 33,294.17 pounds of punch mica having a total gross value of $434,298.The several properties of the district are variously owned by estates, individuals, and the State. When active, all wore under lease or sublease to individual operators.The deposits are in an area of pre-Cambrian schists adjacent to a small granitic outlier of the Idaho batholith. The pegmatites are nearly concordant in dip and strike to the foliation of the enclosing schists. The more persistent bodies are usually tabular, lenticular, or pegmatite. Individual dikes range in length from 10 feet or less to 300 feet.The recoverable crude mica content of the pegmatites ranges downward from a maximum of 115 pounds per ton of pegmatite mined. Material discarded in rifting and trimming operations further reduces recovery to a maximum of 5 pounds per ton -of pegmatite mined. The average recoverable sheet content of the 'recently operated .deposit is estimated at 2 pounds per ton of pegmatite -mined. Available data indicate that about 21 percent of the district's recent production of trimmed sheet mica has been ""Group A"" material suitable for exacting condenser requirements. A few of the dikes contain local concentrations of beryl.Reserves of the three known major deposits of the district are estimated at about 600 to 1,000 tons of combined ""indicated"" and ""inferred"" crude block mica. One of these deposits is inferred to contain between 150 and 450 tons of beryl.It is believed that those mica reserves are minable only under a cost-market price ratio similar to that established during 1943 and 1944. A small part of the reserves can be ""high-graded"" under the present price structure. Profitable recovery of the beryl would require a market price four to five times that paid in 1944.Preliminary examination of the Avon mica district was made by the Bureau of Mines in the summer and fall of 1942. A study of the Muscovite mine and a brief reconnaissance of the surrounding district led the Bureau to recommend that the district be explored by angle-dozer trenching."

Jul 1, 1946

By H. B. Humphrey, F. E. Cash

The following information on accidents in Alabama during 1930 was compiled from data obtained from the companies represented in a course on accident prevention given by the United States Bureau of Mines in Birmingham. These mines produced nearly three-quarters of the tonnage of that State for the year, and included most of the larger operations in the district. The figures are probably representative of the mines which are doing recognized safety work, and are better than the average for all the mines in Alabama. Table 1 lists the days lost in accordance with the weights given to fatalities and permanent disabilities, part and total, which is the scale used in the National Safety Com¬ petition for Mines, conducted by this bureau. By way of explanation, temporary disabilities are weighted according to actual number of calendar days of disability, including Sundays and holidays — that is, all days are counted except the day of accident and day of employee's ability to return to duty. Hernia is classed as a temporary disability to be charged with the actual number of calendar days during which the employee was unable to work. Table 2 gives the number of accidents and the days lost from each cause at 45 coal mines and 7 iron ore mines, also the average frequency and severity rates.

Aug 1, 1931

By N. S. Dalal, X. Shi

"This study reports a new property of the important NAD(P)H-dependent flavoenzymes, glutathione reductase, lipoyl dehydrogenase and ferredoxin- NADP oxidoreductase, that can catalyze a one electron reduction of metal ions such as chromium(VI) and vanadium(V). During the enzymatic reduction process, molecular oxygen is reduced to H2O 2 , which reacts with the reduced metal complexes to generate hydroxyl radicals. Since the hydroxyl radicals have been suggested to play an important role in Cr(VI) toxicity, this study provides a basis for a recent observation that Cr(VI) mutagenesis is strongly oxygen dependent. These results also point to an enzymatic pathway for the metabolism of some metal ions and concomitant generation of hydroxyl radicals. l. INTRODUCTIONThe purpose of this communication is to report that some important NAD(P)H-dependent flavoenzymes (glutathione reductase, lipoyl dehydrogenase and ferredoxin-NADP+ oxidoreductase) can catalyze one electron reduction of metal ions such as chromium(VI) and vanadium(V) and simultaneously reduce molecular oxygen to generate Hi02 and, eventually, the ""OH radical. This finding is significant because (i) the known substrates for the flavoenzymes are organic species and not metal ions, and (ii) the report on the enzymatic formation of the ""OH radical provides a new pathway for understanding the mechanism of genotoxicity of some non-ferrous metal ions. For example, it has been suggested that OH radical is likely to be the major species responsible for Cr(VI) genotoxicity [1-5). The 'OH radical is generated through the reaction of Cr(V) complexes with cellular Hi02 [4,5]. Cr(V) itself is known to be generated from Cr(VI) in various biological systems, in particular, microsomes [ 6), mitochondria [7] and mitochondrial electron transfer chain complexes [8]. However, no specific enzyme responsible for the Cr(V) generation has been identified except possibly glutathione reductase [4]. In this study we have used ESR and spin trapping techniques to show that the flavoenzymes can generate Cr(V) and provide a catalytic redox cycle for 'OH formation in such reactions. Herein we present our results on Cr(VI) and summarize those on other systems. Correspondence address: N.S."

Jan 1, 1990

By Harry R. Johnson

Domestic expenditures by the U.S. petroleum industry have exhibited distinctive shifts in emphasis over the past 20 years. From the end of World War II to 1955, expenditures for all phases of the industry expanded. Although over one-half of all expenditures were for production, the relative emphasis was changed after 1956-58 from production toward processing and marketing. The period 1967-69 marked the beginning of a return to emphasis on exploration and production. These trends in expenditure patterns are logical and rational when related to domestic and international economic conditions and to the widespread application of improved production technology. As the immense job of developing the oil resources of Alaska and other regions begins, the petroleum industry will continue to turn to external sources for working capital. Long-term debt will probably be the principal method of external financing through 1970, but a definite shift toward new common and preferred stocks will be made. Higher product prices may be sought by the petroleum industry, but the economics of crude-oil production, changes in the tax structure, and possible changes in the oil imports control program make the price structure of crude oil and crude-oil products unpredictable at the present time.

Jan 1, 1970

By James F. O'Neill

Brown iron ore deposits in Quitman County , Ga . , were investigated by the Federal Bureau of Mines in cooperation with the State of Georgia , Department of Commerce , and the University of Alabama . Ninety- one holes were drilled , having an aggregate footage of 2,188 feet ; seventy- one holes penetrated 248 feet of iron mineralization . Average thickness of the ore zone was 3.5 feet under an average thickness of 14.7 feet of overburden . The drilling developed inferred reserves containing nearly 30 million long tons of crude ore with an average analysis of 28 percent iron plus minor quantities of manganese . Test work done by the Bureau on the crude ore samples indicated that they would upgrade by current log washer practice , with the use of a 1 /8 - inch screen , and yield 4.4 million dry long tons of concentrate with an average analysis of 52.1 percent iron plus manganese . The weight recovery obtained was 14.7 percent . Research studies made by the Bureau showed that the weight recovery would be increased by changing the screen size without any appreciable sacrifice of grade . The average weight recovery was increased to 18 percent with a 10 - mesh screen and 22.8 percent with a 20 - mesh screen . Screen tests studies indicated that there was no appreciable interlocking of the iron and manganese minerals and the clay and silica waste particles of the materials retained on a 200- mesh screen . Clay was prominent in micron - size slimes . Silica was deleterious in the minus 20 - mesh size .

Jan 1, 1965