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By Robert B. Hoekzema

The Bureau of Mines and U.S. Geological Survey completed a 4-yr (1979-82) mineral appraisal of the Chugach National Forest (CNF), AK. This report summarizes the Bureau's placer gold studies in the CNF. Placer mining from the mid-1890's through 1982 produced an estimated 133,800 oz of gold, of which two-thirds was produced prior to 1920. As much as 6,800 oz of placer gold was produced from 1979 to 1982. Most production came from Crow, Canyon, and Resurrection Creeks. Five types of placer gold deposits were identified in the CNF: (1) alluvial placers, (2) bench placers, (3) eluvial placers, (4) glacial placers, and (5) marine placers. Placer sampling indicated a potential for gold production from alluvial and bench placers associated with historically mined drainages such as Crow, Canyon, Resurrection, Sixmile, and Mills Creeks and from unmined drainages including the Avery, Kings, Snow, Copper, and Tasnuna Rivers and several smaller streams throughout the CNF. Results of fineness tests indicated that gold from the CNF ranges from 455 to over 950 fine. Subsequent investigations in drainages with anomalous placer sample values also identified previously unknown lode mineralization.

Jan 1, 1986

By Keith S. Olson

During 1982 and 1983, the Bureau of Mines concentrated its fugitive dust control research on haulage road dust suppression by newer chemi-cals relatively unknown in the mineral industry, innovative dust control designs for haulage trucks, chemical tailing basin stabilization, and combined chemical and vegetation tailing basin stabilization. Relatively unknown dust suppression chemicals and innovative aerodynamic modifications to haulage truck fender designs were tested on a Minnesota sand and gravel operation haulage road. Magnesium chloride salt at 95-pct control efficiency and a petroleum derivative at 70-pct control efficiency were effective in suppressing dust generated by haulage vehicles; however, none of the fender modifications were successful. Commonly used dust suppressant chemicals were tested on a Minnesota taconite tailing basin to reduce the dust lift-off during the spring and fall dry seasons. The most successful chemical was lignin sulfonate with a seasonal cost of less than $200 per acre to achieve 90-pct dust control. When chemical treatments for immediate dust control were com-bined with revegetation for permanent control, the most promising chemical treatment based on vegetation response was lime-neutralized lignin sulfonate.

Jan 1, 1987

By Charles D. Haynes

Outside air for ventilating coal mines in Alabama varies considerably in both temperature and moisture content during the year. Alternate condensation and evaporation of the moisture on mine roofs may result in stresses detrimental to the strength of mine roof. It is well known that the clays in shales absorb moisture, and many investigations have noted the weakening of shales by absorption of moisture. Parker (1970) concluded that there is an annual cycle of rock deterioration in mine roof rock caused by the annual temperature-humidity cycle at the surface. He further noted that moisture reduces the strength of dry rock by one-half, that moisture added to dry rock can cause failure in compression, and that drying of wet rock causes tensile stress buildups by shrinkage. His recommendations for alleviating the moisture-temperature problem was to seal the rock in critical areas and to control ventilation so that air temperature will be lower than rock temperature. The latter recommendation will avoid condensation on the rock surfaces. Hartmann and Greenwald (1941) published the results of a very comprehensive experimental project to determine the effect of temperature and humidity changes on the behavior of mine roof. Their general conclusions included statements that roof rocks were very sensitive to moisture changes, but had low coefficients of thermal expansion. The coefficients were twice in the direction normal to the bedding plane as compared to the parallel

Jan 1, 1975

By N. S. Dalal, J. F. Mega, X. Shi, V. Vallyathan

Several studies have suggested that pulmonary toxicity to asbestos and silica may be mediated through oxidant-induced cell injury. We have reported recently that surface radicals associated with freshly fractured silica may be an imponant factor in cell injury and induction of pulmonary disease. Although the generation of oxygenated radicals in dust-cell interactions has been demonstrated, there are no data correlating the toxicity of a dust with the level of oxygen radical generation by the dust during its interaction with phagocytic cells. In the present study, we have investigated the in vitro generation of oxygen free radicals from human neutrophils and rat alveolar macrophages stimulated with freshly fractured silica, aged silica, amosite, crocidolite, chrysotilc, and a nontoxic dust, barite. Electron spin resonance (ESR) with the aid of a spin trap phenyl-N-ten-butyl nitronc (PBN) was used to measure the oxygen radicals generated during phagocytosis of the dusts. The relative toxicity index and ESR peak heights, on an equal surface area basis and normalized to barite as one, showed a direct relationship. The normalized toxicity indices and peak heights were: silica, 3.5 versus 2; chrysotile, 4 versus 2; crocidolite, 11 versus 8; and amosite, 26 versus 13. Addition of hydroxyl radical scavengers such as catalase, dimethyl sulfoxide, 1,3 dimethyl-2-thiourea (DMTU), sodium benzoate, and mannitol prevented the radical generation. Carmustine, a glutathione reductase- glutathione peroxidase inhibitor, caused a 5-fold increase in the radical generation. These results indicate that a nontoxic dust such as barite generates toxic oxygen radicals at a minimal level that can be quenched by the normal cellular defense system. For toxic dusts such as silica, amositc, chrysotile, and crocidolite, the potential for oxygen radical generation is enhanced by their surface propenies, physical dimensions, and the surface-based radical-generating redox sites. The enhanced radical generation may impair the cellular defense system, resulting in cell injury. Use of scavengers, chelators, and potentiating agents suggests the membrane-based oxidase system as the probable primary source of the radical-generating system. The data presented herein suggest the generation of oxygen free radicals as an important primary event in silica- as well as asbestos-induced cell injury.

Mar 1, 1992

By A. Y. Lee

Prior work at the Bureau of Mines resulted in the successful development of a bench-scale, combination electrorefining-electrowinning method for recycling the lead from scrap batteries using waste fluosilicic acid (H2SiF6) as electrolyte. This paper describes larger scale experiments. Anodes cast from scrap battery lead were electrorefined in a 20-L multielectrode cell for 3 to 7 days. The anodes, containing 2 to 2.5 pct antimony, were ideal for obtaining firm and adherent slime blankets. Cathode deposits, assaying 99.99 pct Pb, were obtained, with current efficiencies near 99 pct. Sludge leaching was done in 100-L tanks followed by filtering in 61 cm square vacuum pan filtersu Lead of greater than 99.99-pct purity was recovered from the filtrate by electrowinning in a 20-L multielectrode cell using insoluble Pb02-Ti (lead dioxide-coated titanium) anodes and pure lead cathodes. The fluo-silicic acid electrolyte depleted in lead was repeatedly recycled to leach more sludge, and there was no problem with impurity buildup. The amount of Pb02 formed on the anodes during electrowinning was less than 1 pct of the total lead deposited on the cathodes, as long as the phosphorus concentration in the electrolyte was greater than 1.3 giL. Emissions of lead in air were less than 10 ~g/m3, well below the proposed OSHA limit of 50 ~g/m3.

Jan 1, 1984

By F. G. Miller

[Petroleum technoloF;istz and 1 rot-re s s ive OT e:?ztors. con stantl;, are striving to increase the percentage of oil that y to recovered from reservoir rocks throe::;:: wells. The exhaustive studies that have been made of the function of natural r:; as in t h-_ T r odI action of oil, for cx<n.mTnle, have aidedd of.erators greatly in incroasin,&apos; the q-:Arrntity of oil recovered from reservoirs. i.rtural gas dissolv3d in ar--d otinerwwisa &apos;1s&apos;.,ocintjd under rre3suro with oil in roscrvoir roci.s, howover, i:; not the only source of energy available for moving oil through sa&apos;:&apos;l to wells. l becoming "reservoir-energy conscious&apos;t engineers hr-vo -d o^.rued t}:-Lt in many petroleum reservoirs the edgewater flanking t -,e oil accum.-,lation conetitutos a potential source of onergy capable, tL-ou;_h rro? gr control, oil&apos; increasing oil-recovery efficiencies materially. i o ]enter is ti-.-,, on-cronchinunt of water into the oil- and gas--fillod ?art of the reservoir considered as an evil to be combatted by devious mot&apos;:r:ci :i,.t r,ttL er a natural conseque::c4, incident to the withdrawal of oil nna gas from the wells, that nay be T.usod advantrt eou ;ly in lonr`t}toning tr e r&apos;lowin g lift of wells a.nd, i norcas in:; the economic recovery of oil and Little is known about the by which water off: oratos in driving nil throe:gh reservoir roc:-.:,, nd i:. a scorcity of rubli:;Lad informs-¬t .on nn rates of :)Ov.:m.,:- t of : r.tcr ..at v:1:11 res,-_lt in ^r i-nu oil recoveries. Bureau of :fines engine_:? ; - reciate. the r,aucity of scientific knowledge or. the &apos;test methods of a,r.lying the natural water arive to in¬crease oil-recovery efficiencies ant ,i.;?l __-itir?,~ ting irties that will, they hope, Contribute to t.1&apos;.e T ros?Jr.t. small _ %nd of information now av tilable on tt:e cubjoct. This r».crt a oyno-.::is or brief comrilnt.ion of r,ublished data and thought accuinulnt.~d so far, to la)or;~.tory ox-:erimnntrr¬tiorn and, further rosoarch on the z_rrinciplos unri;rlyir..g the natr.rr+1 eater drive no it nffocts oil recovery. :Lie writer:: Lore that t.i.c cx-nositiorn of a?rzilable inforr-at ion i rcs?r.toi in the rernrt r .-II .i ,.1rtt cor_jt_-i:ctive tho.-_.I_t and efforts loadir,-z to -:ard more con.r .ote extraction n;&apos; o tl from reservoirs.]

Jan 1, 1938

By Roy L. Wilfong

The linear expansion of high-purity oxides of yttrium, cerium, samarium, europium, and dysprosium was determined by the interferometric method for the temperature range 25° to 1,000° C. Single-crystal magnesium oxide and single-crystal aluminum oxide were used as reference materials. The bulk density and crystal form of the nonreference materials also were determined. The coefficients of linear expansion in the range 25° to 1,000° C were found to be 8.10 x 10-6 for yttria, 12.10 x 10-6 for ceria, 10.81 x 10&apos;6 for samaria (monoclinic), 10.35 x 10-6 for europia (monoclinic), and 8.13 x 10-6 for dysprosia, each given in centimeters per centimeter per degree Centigrade. A detailed investigation of the interferometric technique for measuring thermal expansion in this temperature range was made. The interferometer was found to be a precise tool but only when adequate precautions were taken. These precautions are described.

Jan 1, 1963

By E. D. Gardner

This paper on the square-set system of mining embodies the results of a special study of the subject made as a part of the Bureau of Mines general investigation of mining methods and costs. Data for the paper were gathered by the authors during visits to mines using square-set mining, from Information Circulars prepared by consulting engineers to the Bureau on mining methods at individual mines, and from articles in the technical press and the Transactions of the American Institute of Mining and Metallurgical Engineers. The square-set system of mining is very widely applied and is one of the oldest methods in use in the United States. It is mainly employed for extracting relatively high-grade ore in heavy ground. It is also useful in taking out pillars left in mining by other methods. It is used to some extent as an auxiliary method with many underground systems and as an alternate with cut-and-fill, shrinkage, and open-stope methods when heavy ground is encountered. In some cases as much as 50 per cent of the ore may be extracted by square-setting at mines listed as using some other method of mining. A large tonnage is mined yearly by square-setting, principally in the Western States.

Jan 1, 1933

By L. P. Purtell

The performance of ten anemometers of several types has been measured at low air speeds. Multiple calibration runs provided sufficient data for measuring random error about the mean calibration curve in addition to the difference between indicated and true speeds. Measurements were also performed of the minimum operating speeds of the anemometers.

Jan 1, 1979

By E. C. Lane

This paper is the first putt of a report giving the results of the Bureau of Mines&apos; twenty-third semiannual survey of motor gasoline marketed in the United States. A companion report, Part II, is in preparation and will give a more detailed discussion of the whole survey. Results of the determination of copper-strip corrosion, color, sulphur content, copper-dish evaporation residue, and gum content as given by the Bureau of Mines steam-oven method will be presented in the second paper, which will also include the prevailing retail price and the tax at the time the sample was taken. This paper deals specifically with data relative to gravity, Reid vapor pressure,&apos; and distillation (method 100.13).6 The samples tested were divided into "competitive-price gasolines" and "premium-price motor fuels," a method of presentation that was begun with the twenty-second semiannual survey. A total of 312 samples were collected from service station pumps in 20 cities throughout the United States. Of this number of samples, 207 were "com-petitive-price gasolines" and 106 were "premium-price motor fuels." All of the samples were collected in March, 1931, and analyzed at the Petroleum Experiment Station of the United States Bureau of Mines at Bartlesville, Okla. "Competitive-price gasoline" includes those fuels that are sold at the generally recognized local base price and all fuels that are sold below that price. All fuels that are sold at an advance over the generally recognized base price are placed in the class of "premium-price motor fuels." These fuels include Ethyl gasolines, benzol blends, "high-test" fuels, and those fuels that owe their "anti-knock" rating to the process of manufacture rather than to the addition of other material such as Ethyl fluid or benzol. The term "high-test" is generally applied to motor fuels that are more volatile than the regular competitive-price gasolines. "High-test" fuels may also have a high anti-knock rating.

Jan 1, 1931

By Jr. Gabler

Because of concern over the availability and reliability of an uninterrupted supply of manganese and other materials, the U.S. Congress requested that the U.S. Bureau of Mines (USBM) study the /low of strategic and critical materials in the economy to delineate and quantify the production areas where metal values are lost. As a result, the USBM developed a generic computerized commodity flow model that is readily amenable to updating. The original model developed for cobalt, with slight modifications, was used to track the flow of manganese. This report follows the flow of manganese through its metallurgical and chemical applications and highlights areas where significant losses occur owing to downgrading, export, or disposal. The study indicates that materials containing 695,000 short tons (st) of manganese were consumed domestically in 1990. Scrap recovery specifically for manganese recycling was insignificant. However, considerable manganese was recycled through processing operations as a minor component of ferrous and nonferrous scrap and steel slag. The major loss category is manganese lost in steel processing, 323,156 st or 46 pet of the 1990 apparent consumption. Most of this loss reports to steelmaking slags. Recovery from slags is technically feasible, but is not economically feasible.

Jan 1, 1995

By Deno M. Pappas

This report presents results of a U.S. Bureau of Mines study of longwall gob material. The objective of this work was to determine material stiffness properties of the gob for use in numerical models of rock mass response to longwall mining, Photographs of actual mine gob were digitized to obtain approximate particle size gradations of gob material. The gradation curve was shifted down to a laboratory scale, and 20 uniaxial compression tests were conducted. Varying the maximum particle size was not found to affect the stress-strain behavior, but changing the gradation appeared to influence the stress-strain behavior. The stress-strain relationship of the simulated gob material was nonlinear, the stress-secant-modulus relationship was approximately linear, and the stress-tangent-modulus relationship was approximately a second-order polynomial function. Equations were generated from these curves, providing numerical modelers with a means to estimate gob moduli based on the stress level. In addition, the experimental data were statistically evaluated using multiple regression analyses, producing a series of equations to predict the secant and tangent moduli from the given stress level, bulking factor, rock strength, and thickness-to-width shape ratio of the particles.

Jan 1, 2010

By Robert J. Timko

This U.S. Bureau of Mines study examined spontaneous heating episodes in coal mine pillars in an active underground coal mine. The information obtained from these incidents was then analyzed to learn which sampling methods provided the earliest indication of pillar heating. The objective of this study was to discover if the location of future events of pillar spontaneous heating could be inferred from the available information. The spontaneous heating-prone area in this evaluation involved pillars located just inby the mine portals. Several detection methods were used to determine gas levels outside as well as inside the affected pillars. It was hoped that, by incorporating external and internal sampling methods into an organized pro-gram, locations undergoing spontaneous heating could be determined more readily. This study found that by drilling small-diameter boreholes into the pillars, then obtaining gas samples from the affected pillars, the ability to locate early spontaneous heating episodes was improved. However, the ability to accurately predict future spontaneous heating events remains in question.

Jan 1, 2010

By J. A. Kost

A dust-control manual was prepared for use by mine operations personnel. The manual documents state-of-the-art control techniques, dust sampling, and use of personal protective devices. Content addresses advantages/disadvantages of control techniques, design and operating specifications, and implementation and maintenance guidelines. An indexed list of selected references is also included. In addition to the completed manual, this report documents work performed in the course of its preparation.

Jan 1, 1981

By C. P. Mishra

The Bureau of Mines investigated the availability of mercury from 22 deposits in market economy countries. The 15 significant deposits evaluated have demonstrated resources of approximately 25 million metric tons of ore containing 5.3 million flasks of mercury and account for more than 85 pct of the demonstrated resources for market economy countries. Using data gathered as part of its Minerals Availability Program, the Bureau determined the mercury production potential of each deposit. At a January 1984 mercury market price of $300 per flask, the deposits evaluated could economically produce an estimated 2.5 million flasks of mercury from six mines operating at the time of this study; no mercury is available at this price from nonproducing operations. At $600 per flask, approximately 4.5 million flasks of mercury are available. For production costs up to $300 per flask, operating mines could supply mercury at the current production rate of 114,000 flasks per year until 1988, when the amount of mercury available from these deposits would decrease. This decline could be offset by the development of resources currently reported at the identified level (17 million flasks) at much higher production costs.

Jan 1, 1985

By N. S. Dalal, B. Jafari, F. H. Y. Green, M. Petersen, V. Vallyathan

"Stable coal radicals (SCRs) were detected by electron spin resonance (ESR) spectroscopy in the lung tissue of autopsied coal miners. The SCR concentrations were measured in the lung tissues from 98 coal miners with and without (a) coal workers' pneumoconiosis (CWP), (b) cancer, and (c) a history of cigarette smoking. Concentrations of SCRs were also determined in the lungs of nonminer controls. The SCR concentration was related to longer mining tenure, CWP disease severity, lung cancer, and cigarette smoking. The mean concentration of SCRs in the lung tissues of miners with 30 ± 1.4 y of coal mining exposure was 5.3 ± 1.3 x 10"" spins/g versus controls who had a nondetec¬table level (< 10 15 spins/g). An increase in disease severity was accompanied by a progressive increase in SCR concentration. A SCR concentration of 4.8 ± 0.7 x 10"" spins/g was found for simple CWP (with moderate coal macules) versus 7.8 ± 4.6 spins/g lung tissue for complicated CWP (with progressive massive fibrosis). Significantly higher (i.e., 10 x 10"") concentrations of SCR in the coal miners' lung tissues were associated with an exposure history in the anthracite regions of northeastern Pennsylvania. These results in¬dicate a possible role for SCRs in the disease process. Furthermore, ESR appears to be an adequate methodology for the quantitation of coal dust retained in the lung and for distinguishing exposures to anthracite and/or bituminous coal.THE PREVALENCE AND SEVERITY of coal workers' pneumoconiosis (CWP) differ markedly between geographic locations, mines, and coal fields irrespective of comparable levels of exposure to coal mine dust These differences cannot be fully explained by the presence of silica and other minerals in the coal mine dust.' Rank of coal is also an important factor in the pathogenesis of CWP. Equally important is that the prevalence of CWP decreases from east to west in the United States,' and South Wales miners develop more severe CWP than miners in Scotland.' However, there are conflicting reports that cast uncertainty on the influence of rank of coal in the development of CWP."" These problems are complicated but will be solved as new technology emerges and as more is learned about the disease process."

Mar 1, 1992

By B. W. Gandrud, G. D. Coe

"INTRODUCTION The Southern Experiment Station of the U.S. Bureau of Mines, cooperating with the University of Alabama and Alabama coal producers, has made a series of investigations of the washability of coal from commercially important bens of Alabama. The results of 13 investigations pertaining to the Mary Lee, Clark, Black Creek, Jefferson, Pratt, Corona, Carter Brookwood, Blue Creek, Thompson, and Woodstock beds have been published. 4/ This report, the fourteenth of the series, deals with run-of-mine coal from the Henry Ellen bed at the Acmar No. 5 mine of the Alabama Fuel & Iron Co.The Acmar mine is 1/2 mile west of Acmar, Saint Clair County, in the northern part of the Cahaba field. Present production at the mine is about 800 tons per day, all of which, accept the lump coal, is treated in jigs. The washability data were obtained by means of screen-sizing and float-and-sink tests. There are included, also, tests showing the extent of liberation of impurities by recrushing the coarser sizes of coal from the top bench and tests showing the flakiness in selected sizes.SAMPLING AT THE MINEThe Henry Ellen bed at Acmar consists of two benches separated by a shale parting. At the point of sampling the top bench was 6 feet 3 inches thick and contained a 1-inch and a 1 1/2-inch band of bone. The bottom bench was 5 feet thick and was separated from the top bench by 20 inches of shale. In taking the samples for the washability study the working face was squared up, and a representative 2-ton section was out from each bench. The shale parting was discarded, according to usual mining practice."

Nov 1, 1936

By Thomas R. Bur

The strain and pressure gage methods for evaluating the relative performance of explosives in rock were compared. This comparison was based on a study of the responses of strain and pressure gages to explosion-generated seismic waves. Several explosives) representing a wide range of detonation pressures) were used. In general the relative performance of these explosives) as determined from amplitude) impulse parameter) and energy parameter measurements) is the same if the compressive portion of the strain pulse and the comparable portion of the pressure pulse are considered. Other similarities and differences of the two methods are also discussed.

Jan 1, 1967

By Michael Horn

This report presents a structural analysis of the economies of Spokane County, Washington and 21 surrounding counties. An economic trading region made up of 22 eastern Washington, northern Idaho, and western Montana counties, with Spokane, Washington as the central place, was defined for this study. The Micro IMPLAN modeling system with the 1990 county database was used to create an Input/Output based model of the regional economy. The leading industries, with respect to employee compensation, employment, value of exports, and total industry output are shown for each county and the region. The value of total industry output from natural resource based industries is also shown (or each county and the region. The total industry output from the Spokane Economic Trade Area (S ETA) region is valued at $22.3 billion. The SETA region provides $7.1 billion in employee compensation to a work force of 374,000. Spokane County, Washington accounts for about 50 percent of the regional total output, employee compensation, and employment. Both Spokane County and the region as a whole produce about 80 percent of total industry output for final demand with the remaining 20 percent going to intermediate inputs for further production. About $7.4 billion of the $22.3 billion SETA output is exported from the region. Spokane County exports about $4.7 billion, or 41 percent of the $11.5 billion Spokane County output. Exports account for more than 50 percent of the total output in 12 of the 22 counties within the region. Based on the output of the top 25 industries in each county and the SETA region about 9 percent of the industry output from Spokane County and 18 percent of the regional industry output come from natural resource based industries. For counties other than Spokane County, total industry&apos; output from natural resource based industries represents from 12 percent to 81 percent of county output from the top 25 industries. Natural resource industries account for more than 50 percent of total county output in 8 counties within the region

Jan 1, 1994

By D. K. Deardorff

The purpose of this work was to investigate the hafnium-carbon phase diagram. Alloys used to study this system were prepared from high-purity components by both consumable-and nonconsumable-electrode arc melting. Data for the diagram were obtained on the alloys by metallography, optical pyrometry, thermal analysis, heat treatment, and X-ray diffraction. The data indicate that a carbide compound occurs over considerable range of composition, and that one of each of the following types of reactions occurs in the hafnium-carbon system: Peritectoid, peritectic, and eutectic. The maximum melting temperature of hafnium carbide is 3,840° C at 49 to 50 atomic percent carbon, and the composition range of hafnium carbide at temperatures of 2,150° to 2,380° C is from 37.0 to 48.5 atomic percent carbon. The hafnium a-S transformation temperature is raised on alloying with carbon from 1,750° to 1,890° C, where a peritectoid reaction isotherm occurs. Alloying hafnium with carbon increases the hafnium melting temperature from 2,190° to 2,250° C, at which temperature a peritectic reaction occurs. Hafnium carbide and carbon react at 3,055° C to form a eutectic of 68.3 atomic percent carbon.

Jan 1, 1967