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By Deborah A. Kramer

This Bureau of Mines report presents a cost estimate of the Bayer process, which is used for virtually all cell-grade alumina production. The report will serve as a reference point to determine the economic merits of processes that have evolved from Bureau of Mines investigations on technology for producing alumina from domestic nonbauxitic raw materials. The Bayer process involves dissolving the alumina present in bauxite in a caustic solution at high temperature and pressure. After the un- dissolved impurities are removed, the solution is seeded to produce an alumina trihydrate precipitate. This precipitate is filtered, washed, and calcined to produce the cell-grade alumina product. This cost estimate is for a plant producing 1 million tons of alumina per year. The estimated operating cost is approximately $250 per ton of alumina.

Jan 1, 1983

By E. L. Garton

Bureau of Mines routine crude-oil analyses of 88 samples from 60 fields are presented in this report. Similar analyses from other fields in California have been published in previous reports listed in the appendix, page 52. Yearly production of crude oil in California and the percentage of United States production represented by California production for 1948-54 are given in table 1. [ ] Analyses in this report are of samples from the fields listed in table 2, with production data for 1953, cumulative production through 1953, and year of discovery of each field. Information regarding the source and general characteristics of the samples is included in table 3 with a summary of analytical and computed data.

Jan 1, 1956

By Hal D. Peterson

In research sponsored by the Bureau of Mines, a technique was developed for simulation of heap leaching on uranium ores. The equipment used for this simulation consisted of 2-ft-diam columns, constructed in sections, such that ores as coarse as minus 4-in could be treated in bed depths ranging from 8 to 18 ft with test condition variations. The technique consisted of the separate steps of ore preparation, column loading, charge wetting, leaching, washing, and residue recovery. For the ores studied, sulfuric acid was found to be generally superior to alkaline lixiviants. The rate of uranium extraction by acid leaching proved" to be primarily a function of percolation rate, alkalinity of the ores and oxidant requirements of the ores. Column leaching was closely comparable to field-scale heap leaching in terms of uranium extraction rate and recovery results. Acid and oxidant requirements were lower for the field-scale operation. All column tests, as well as the field-scaly heap, achieved in excess of 96-pct uranium extraction on a Bear Creek, Wyoming ore.

Jan 1, 1985

"INTRODUCTIONThe information compiled in this volume initially formed the response by the Generic Mineral Technology Center for -Respirable Dust (GTCRD) to a review of its research and technology transfer programs performed in 1990 by the Advisory Committee on Mining and Mineral Resources Research. This review for each mineral technology research center is accomplished, as required of the Bureau of Mines by the House/Senate Joint Conference Committee, through site visitation to the research institutions of the GTCRD and an in-depth questionnaire. The information provided by that questionnaire becomes an important factor in their recommendations concerning future directions of the program.The site visitations took place during January and February 1991 at the Milton S. Hershey Medical Center~ The Pennsylvania State University, West Virginia University, University of Minnesota, and Michigan Technological University, in addition to an in-mine visit conducted at the Loveridge Mine in West Virginia. The questionnaire was prepared and made available to the Advisory Committee and the Research Council for their review at the GTCRD annual project review meeting in Hershey, Pennsylvania, in April 1991.The comprehensive nature of the questionnaire and the scope of the information contained therein make it an excellent retrospective of the Center. Having a clear vision of where the Center has been and knowing where it is now helps to guide it into the future. It is believed that such a detailed view of the Center's facilities and research program will be of value to Center personnel and Advisory Committee members. Each aspect of the questionnaire was examined, answered in detail and documented thoroughly. With the completed questionnaire as a guide, this review of the Center's activities provides an update to Respirable Dust Center Research Program Review 1988, published in 1989 as the seventh of the Generic Mineral Technology Center for Respirable Dust volumes. As does that volume, this review presents the complete General Mineral Technology Center questionnaire, with the GTCRD's expanded responses and supporting documentation appended. An examination of the research program, Center personnel currently active on GMTC projects, the number of graduate degrees granted with GMTC supports GMTC publications, the degree of individual interaction, technology transfer activities, the reference center, GMTC equipment and facilities, and envisioned plans for future research directions provides updated information in these areas. In addition, this year, information has been included to demonstrate the interaction between the Center's goals and its research projects, with thorough consideration of actual research needs as specified by the National Academy of Sciences. This volume serves as a review of the years 1989 through 1990, the sixth and seventh years of the Center's operation."

Jan 1, 1990

By M. M. Fine

This Bureau of Mines report describes the theory, experimental procedures, and the results obtained to date in the development of the Bureau's process for magnetically roasting iron ores using scrap iron as a means of reduction. Since magnetic separation is an operational step common to magnetic taconite plants, the preliminary research studies emphasized only the novel magnetic roasting step. The studies included the use of automobile scrap, ferrous reductants such as borings and turnings, and prereduced pellets. Technical feasibility of the process was demonstrated both on a bench- and pilot-scale. Quality magnetic concentrates with recoveries of over 90 percent were obtained from a direct shipping ore containing 59.5 percent Fe and from fine grained semitaconites with about 30 percent Fe.

Jan 1, 1966

By A. C. Rice

Investigation of a variety of mines to determine efficiency for rare- earth extraction has resulted in a solvent extraction technique wherein Primene 81-R,4 N-benzylheptadeeylamine (BHDA), and Primene JM-T give favorable extraction from sulfate solutions. Extraction from chloride, nitrate, and perchlorate solutions is negligible. Distribution coefficients for 10 rare-earth elements with Primene 81-R establish an extraction sequence beginning with lanthanum and proceeding through lutetium according to atomic number. Yttrium and ytterbium are exceptions in the extract ion sequence.

Jan 1, 1962

By H. Kim, R. W. Plummer, T. J. Stobbe, W. G. Jones

"Exposure to airborne dust in coal mines has caused respiratory disease in coal miners. The causal agent in these diseases remains unknown, although the minerals found in and around the coal seam have been implicated. Toxicological studies designed to establish the effect of different mineral combinations and concentrations are lacking because the mineral content of coal mine dust has not been defined. This paper reports the initial results of a study done to characterize the mineral content of the coal mine dust found in a mine in the Upper Freepott seam in Northern West Virginia. Coal mine dust samples were collected using 4- stage cassette impactors at nine locations in the mine. The samples were analyzed by an x-ray microdiffraction film technique supplemented by energy dispersive scanning electron microscopy. Primary size modes of about 17 to 20 micrometers from the samples collected at the haulageway and the returnside of the continuous miner were found. From the returnside of the roof bolter samples, a primary size mode of 12to15 micrometers was measured. The minerals found in high percentages were illite, kaolinite, quartz, and calcite. The distribution of minerals in inter· and intra- location samples showed wide variations. Trends in these variations are presented. Stobbe, T. J.; Plummer, R. W.; Kim, H.; Jones. W.: Characterization of coal mine dust. Appl. Ind. Hyg. 2:95· 100; 1986. IntroductionDisease-associated dusts in coal mine environments continue to afflict miners in today's modern mines. The relationship between exposure to coal mine dust and the development of various respiratory diseases has been well recognized; however, the reasons for variation in occurrence of these diseases among miners in different geographic areas,(1) rank of coal seams,(2-3) and jobs (4) remain uncertain. Several papers have reported on the causal agent in the development of these diseases. Davis (5) found that the percentage of the non-coal minerals present in the lungs of deceased miners increased as the level oi pneumoconiosis became more severe. Reisner (6) reported that cell damage caused by coal mine dust increases with the mineral and quartz content of the dust and with the geo· logical age and rank of the coals. Two studies, investigating the in vitro effects of mineral dusts. reported by Seemayer and Manojlovic (7) also obtained positive correlation between cytotoxicity and the mineral content of coal mine dust. Gormly (8) postulated that destruction of macrophages by certain mineral dusts is the first step in the development of pneumoconiosis. In 1980, Adamis and Timar (9) reported that quartz. sandstone, slate. respirable colliery dust. bentonite, illite, and some kaolins had cytotoxic effects on rat peritoneal macrophages""in vitro."" Walton,(10) however, reported that the presence of high clay, illite, and kaolin mineral exposures reversed the hazards associated with increasing quartz exposures. This finding was supported by Le Bouffant and coworkers.(11) They reported that illite present in coal mine dust strongly inhibited the pathogenic effects of quartz while kaolin had a weaker inhibitory effect."

Mar 1, 1989

By Joseph M. Singer

Ignition of hybrid coal dust - methane - air mixtures by hot- turbulent - pulsedgas jets was investigated . The turbulent jets were generated by explosions in a primary chamber of stoichiometric mixtures of methane , oxygen , and nitrogen . The hot - gas ignition apparatus provided an adjunct means of testing , on a small scale , the type of ignition that exists in large - scale galleries or in coal mines . = coal particle The temperature Ignition variables were channel diameter , channel length , size , fuel concentration , and temperature of the hot - gas jet . of the hot jet was varied by changing the oxygen indices ( OI ) of the primary explosion mixtures . Coal dust having approximately 37 percent volatile matter was used . 02 O2ટ + N₂ The hybrid coal dust - methane - air mixtures required higher jet temperatures ( higher oxygen indices ) for ignition than the single fuel component methane - air mixtures . Methane in air concentrations less than the lower flammable limit of methane could be ignited in the presence of coal dust if the jet temperatures were increased . A specific explosion transmission ( ignitability ) curve existed for each coal dust concentration . The total fuel concentrations at the lower limit of each ignition curve was always close to or greater than stoichiometric , indicating that not all the coal dust was involved in the ignition .

Jan 1, 1964

By R. C. Gabler

Effective recycling or disposal of flue dusts is a continuing problem, particularly for secondary smelters treating low-grade Cu scrap. The Bureau of Mines investigated a variety of flue dust treatment approaches and demonstrated the technical feasibility of a bench-scale alkaline method that includes leaching, cementation, precipitation, and roasting. Flue dust was leached at room temperature with an alkaline solution of (NH4)2C03 and NHpH to solubilize ZnO and Zn metal. Some copper, lead, tin, and most of the zinc were dissolved in the leach step. Copper, lead, and tin were recovered in the cement product. The Zn in the flltrate was precipitated by pH adjustment to neutral using CO2 injection. The Zn salt was flltered from solution and roasted to give high-purity ZnO. The leach residue, enriched from 4.3 to lOA pct Sn, could find a ready market; the metallic cement product can be recycled back to the copper converter; and the high-purity ZnO product can be sold in several markets, leaving no material for disposal. The possibility for recycling of reagents, lower energy demand, and low environmental impact make this method economically and environmentally attractive for recycling secondary copper smelter flue dusts.

Jan 1, 1988

By Robert N. Roby

This report is one of a series based upon investigations made and being made within the Missouri River Basin in Montana by engineers of the Bureau of Mines , Albany Branch , Mining Division . These investigations are made primarily to provide preliminary information to Department of Interior agencies and others concerned with the planning of the proposed Federal power developments within the Missouri River Basin . The present report has been designed to permit public distribution of the factual data obtained . The field investigations in Meagher County were made during tually all 1948 ; Vir- known metallic mineral occurrences within the county were investigated ; some nonmetallic mineral deposits also were investigated . The investigations cannot be considered complete , however , because some long-inactive mines or prospects may have been missed . Most of the old mine and prospect openings are caved; many are completely inaccessible . Many of the claims located years ago have been abandoned ; others have been relocated under different names and ownerships . Because of such conditions , much of the information regarding their development and operation necessarily has been obtained from Federal and State publications , supplemented by information provided by owners and local residents .

Jan 1, 1950

By Alexander May

The U.S. Bureau of Mines investigated the application of oxidation-reduction potential (ORP) and pH measurements to environmental studies of mining and mineral processing wastes, and developed a computer program to estimate the concentrations of species of lead present in samples from a lead processing waste site. The methods and techniques for the ORP-pH measurements were investigated using known standard solutions made in the laboratory, samples from a ferric oxide waste disposal pond at a rutile production plant, and samples of well water and stream water from the lead processing waste site. ORP values were measured from 5 to 80 °C, from pH 1 to pH 12, and at various ratios of oxidant to reductant. The ORP-pH values can help identify valence values and species of ions present, including those of major, minor, and trace concentrations, and also indicate possible reactions at various pH values. The ORP measurements versus temperature yield data from which thermodynamic values can be calculated. The application and limitations of these measurements are discussed, and a brief discussion of the computational program to identify species of lead is presented.

Jan 1, 2010

By J. Nielen van der Merwe

The move toward partial pillar extraction versus full pillar extraction has necessitated a new approach to underground section stability. When pillars are mined too small to support the weight of the overburden, they will, in some cases, remain stable for a considerable period; in other cases, they will collapse unexpectedly and violently. There is no discernable difference between the pillar safety factors of the failed and stable cases. The explanation lies in the characteristics of the overburden layers. A method is proposed that recognizes the overburden characteristics in the evaluation of stability. Two stability factors are calculated: one for the pillars, the other for the overburden. Using this method, it is possible to make use of the bridging capabilities of overburden layers to prevent pillar collapse. It is possible to scientifically design partial pillar extraction layouts that will be safe. Using energy considerations, it is also possible to prevent violent failure of pillars.

Jan 5, 1999

By John Nagy

Tests were conducted in the Experimental coal mine to study some of the factors that should be considered in fighting mine fires and to obtain data on the effectiveness of different types of extinguishing agents. The investigation was confined to class "A" fires in a zone 20 feet long, involving coal burning on the floor, on the floor and ribs, and on the floor, ribs, and roof of the mine entry. It was determined that the time elapsed between ignition and attack of the fire is very important. A fire in the early stages was found to be controlled more easily and quickly than a similar fire that had burned longer. It was also found that, under suitable conditions, a fire in the floor, ribs, and roof develops very rapidly and consequently might spread over a considerable area if not brought under control quickly. The ventilating current affects fire-controlling operations markedly. Attack in intake or fresh air is highly advantageous, the chief inconvenience being the radiant heat from the fire. Attack in direct return air was impossible for the fires tested in this investigation, because of the high temperature. Universal-type gas masks for noxious gases and smoke offered no protection against the intense heat. Approach to a fire in the return air behind a water-fog curtain is not feasible unless the direction of air flow can be reversed. In one" test fresh air was carried to the fire area with a line brattice. Although the entire controlling operation was in fresh air and masks were not necessary, it was considerably more difficult to control the fire than when a similar fire was attacked in intake air.

Jan 1, 1950

Provide the technology to remotely reset circuit breakers on continuous mining machines used in extended cuts.

Jan 1, 1994

By Carroll W. DeKock

Thermodynamic data for selected metal sulfates were critically evaluated and compiled as part of the Bureau of Mines program to provide a scientific base for use in developing new technology and predicting the feasibility of new processes. Values for Cp°, S°, H° - H°298, -(G° - H°298)/T, ?Hf°, ?Gf°, and log Kf as a function of temperature are given in tabular form. Thermodynamic data were compiled for VOSO4, Cr2(SO4)3, MnSO4, FeSO4, Fe2(SO4)3, CoSO4, NiSO4, Cu2SO4, CuSO4, CuO-CuSO4, ZnSO4, and ZnO-2ZnSO4, together with their stable hydrates.

Jan 1, 1982

By N. S. Dalal, X. Shi

"SUMMARYElectron spin resonance (ESR) measurements provide direct evidence for the involvement of the glutathionyl radical, as well as an isolable Cr(V)-glutathione intermediate in the Cr(VI) glutathione redox reactions. These results indicate a new mechanism for the reduction of Cr(VI) by glutathione in relationship to cellular environment and suggest that synergistic reactions of Cr(V) and GS· might be responsible for the (unexpected) increase in the Cr(VI)-induced DNA-strand breaks at high glutathione levels.INTRODUCTIONWhile the reduction of Cr(VI) by glutathione (GSH) is thought to be a critical' step in the pathogenesis of the Cr(VI)-exposure related carcinogenesis1- 4, the exact reduction mechanism is not yet understood. The following reaction steps have been suggested :(A) Initial step:Cr04 2- + GSH - GSCrOa - (1)(B) At high GSH levels:GSCroa- + GSH - Cr( IV) + GSSG (2)(C) At low GSH levels: GSC rO a - - Cr ( V ) + GS ·(3)Thus far, however, in these reactions, the GS· radical has eluded spectroscopic detection, while the evidence for the Cr(V) formation has been reported positives as well as negative2·. Her~ we present spin-trap ESR evidence for the formation of the GS· radical, and a definitive ESR detection of an isolable cr(V)-GSH intermediate in Cr(VI)-GSH reactions.MATERIALS. AND METHODSESR spectra were obtained at X-band (-9.7 GHz) using a Bruker ER200D ESR spectrometer. The magnetic field was calibrated with a self-tracking NMR Gaussmeter (Bruker, Model ER035M) and the microwave frequency was measured with a Hewlett-Packard (Model 5340A) frequency counter. The spin probes, a-(4-pyridyl-1-oxide) -N -tert-butylnitrone (4-POBN) and 5,5-dimethyl~1-pyrroline-1-ox1de (DMPO) were purchased from Aldrich, K2Cr201 from Fisher and used without further purification. All experiments were done at room temperature."

Jan 1, 1989

By G. R. Hopkins

[A new record in fuel efficiency at petroleum refineries was established in 1939, when a the average e B.t.u. requirements per barrel of crude oil processed declined to a new low of 557,000 B.t.u. (see fig, 1).]

Jan 1, 1941

By George A. Bell

This paper reviewing the leaching practice of the New Cornelia mines of the Calumet & Arizona Mining Co. at Ajo, Ariz., is the first of a series being prepared by the Bureau of Mines on leaching methods and costs in the various mining districts. ACKNOWLEDGMENTS The author acknowledges the assistance of T. G. Chapman, consulting engineer, and E. D. Gardner, supervising engineer of the Southwest Experiment Station, Bureau of Mines, Tucson, Ariz.

Jan 1, 1930

By B. L. Razzaboni, P. Bolsaitis

"The formation of reactive oxygen species resulting from the interaction of silica dust particles with red blood cell membranes was investigated; particularly, the effect of surface hydroxyl (silanol) group concentration on the rate of formation of such reactive oxygen species was investigated. The rate of formation was measured indirectly through the effect of catalase, a hemoprotein peroxidase, on silica-induced hemolysis. It was found that the addition of exogenous catalase to erythrocytes markedly reduces the hemolysis caused by silica particles. Furthermore, the amount of catalase required for deactivation of silica per unit area of particle surface is lower for fumed silica particles and calcined crystalline particles than for uncalcined, crystalline silica, suggesting a correlation between the concentration of OH groups at the silica particle surface and its potential for generation of H2O 2• The addition of albumin, a copper chelator, also decreases hemolysis. These results suggest that the hemolysis caused by silica particles is at least partly related to the formation of H2O2 at the particle surface and its subsequent reaction with Cu+ ions. The relationship between the concentration of surface silanol groups on the silica surface and the amount of catalase required to decrease hemolysis may also provide a method for testing potential fibrogenicity of respirable dusts. IntroductionReactive hydroxyl groups on silica surfaces are known to be cytotoxic and are believed to play a major role in silicosis (1-9). It has been proposed that this cytotoxicity results from hydrogen bonding to cell membranes and a resulting increase in membrane fluidity and permeability (4). Surface hydroxyl groups on silica surfaces have also been shown to interact with carbonyl oxygens in cell membranes (1,5). An extensive study by Nolan et al. (6) of the relationship between the negative surface charge resulting from ionized silanol groups and the hemolytic activity of crystalline a-quartz (Min-U-Sil) has shown a positive correlation between hemolytic activity and the surface concentration of silanol groups. These authors demonstrated that the hydrogen bonding of polyvinyl-N-oxide (PVPNO) with silanol groups, as well as the bonding of metal cations to the ionized sm- groups, results in significant decreases in hemolytic activity. Furthermore, it has been found that the complete removal of surface hydroxyl groups from the surface of respirable silica particles nearly eliminates the hemolytic potential of silica (7), suggesting that hydroxyl groups might be involved in other cytotoxic processes associated with silica-induced lung injury. Reactive oxygen species have been .implicated in cellular damage caused by respirable silica particles. Evidence for the presence .of oxygen radical species (02, OH°, H2O2) generated by silica, especially on freshly formed surfaces, has been produced by various investigators. Kalbanev et al. (8) detected H2O 2 in aqueous suspensions of quartz. Electron spin resonance and spin trapping by Shi et al. (9) confirmed the presence of OH"" radicals in aqueous suspensions of quartz, and Gulumian and van Wyk (10) suggested that both glass and quartz produce hydroxyl radicals in the presence of H2O 2 • Gabor et al. (11) detected the presence of malondialdehydereactive lipid peroxides (i.e., lipid-0°) in cultures of macrophages and respirable silica particles using the thiobarbituric acid (TBA) reaction test. Will (12), however, reported that iron enhances the TBA value of peroxidized lipids, and Scheulen and Kappus (19) found that catalase augmented malondialdehyde formation, thereby increasing the TBA values."

Jan 1, 1990

By J. A. Herdlick

The Star mine, near Neihart, Cascade County, Mont., has been in continuous operation since the construction of a 50-ton bulk flotation mill in 1939. The mine was examined by G. N. Bennett, an engineer of the Bureau of Mines, in November 1942. At that time the life of the operation appeared to be limited and a program of crosscutting and core drilling were recommended. The program had as its objective the investigation of a promising undeveloped area lying west of the Star vein and, if possible, the development of enough reserves in this area to insure continuous operation during the war emergency. Development of additional reserves would then justify necessary changes in the mill in order to eliminate the heavy penalties imposed for excess zinc in the bulk concentrates. The Bureau of Mines work began in February 1944 and was completed in September 1944. The project was started by Wilder R. Brinton and continued by Thomas W. Oster, mining engineers in the Bureau's Montana district office. Beneficiation tests on are and concentrates were made after completion of the underground work. This report presents the factual data obtained during all phases of the Bureau's investigation.

Jan 1, 1949