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By Stephen Krickovic

A degasification experiment was conducted in a Pocahontas No. 3 coalbed mine in Virginia. It involved (1) drilling holes in the coalbed in the out-side headings of a set of five being developed in virgin area, and (2) con-ducting a methane emission rate study as mining progressed and additional holes were drilled. Degasification from all drill holes except the longest in each of the outside headings and the first three drilled (excluding the in-situ pressure hole), was erratic and inconsequential in methane emission rates. The two longest holes liberated 66 and 79 cfm of methane, which is significant for the coalbed, but such quantity lasted a relatively short time; the first three were uniform but low in methane emission.

Jan 1, 1972

By Robert K. Koch, Henry E. Blake

Laboratory tests were made to determine if aluminum fluoride of commercial grade could be synthesized by reacting alumina hydrate with dilute ( 25 to 75 grams per liter of fluorine ) aqueous fluoride solutions . • Products containing up to 90 percent aluminum fluoride ( A1F ) were synthesized by reaction of alumina trihydrate ( A120 3H2O) with either dilute hydrofluoric acid ( HF ) or ammonium fluoride ( NHF) solutions , the ammonium fluoride solution resulting from ammonia ( NH ) desilication of a hydrofluoricfluosilicic acid ( HF - H₂ SiF ) solution . Fluorine recoveries of over 80 percent were obtained with either type of solution . The hydrated precipitates of AlF, and ( NH4 ) , A1F ( ammonium aluminum fluoride ) obtained by reacting hydrated alumina with these solutions were subsequently converted to anhydrous AlF, by controlled heating .

Jan 1, 1964

By Kenneth J. Miller

The Federal Bureau of Mines coal-pyrite flotation process has been modi¬fied to produce a concentrated final clean coal slurry underflow that could be dewatered more effectively by filtration or centrifugation. This change was accomplished by redesigning the Bureau's two-stage flotation pilot plant facility and running the second-stage flotation step with undiluted or only partially diluted first stage coal froth concentrate. Results of the pilot plant flotation tests showed that substantial sulfur reduction could be achieved by flotation with undiluted pulp but some dilution is recommended for maximum selectivity. For example, coal-pyrite flotation in slurry of 25 percent solids yielded clean coal products analyzing as low as 0.7 percent pyritic sulfur and froth reject products containing slightly over 3.0 percent pyritic sulfur. In comparison, coal-pyrite flotation with pulp diluted to about 12.5 percent solids yielded clean coal containing as low as 0.4 percent pyritic sulfur and froth reject of 5.6 to 6.7 percent pyritic sulfur. Despite the need for some dilution, it was concluded that excellent coal-¬pyrite flotation selectivity could be achieved without diluting to 6 or 7 per¬cent solids as done in the earlier work. Thus the economics of coal-pyrite flotation would be improved by easing clean coal dewatering problems and by reducing second-stage flotation cell volume requirements.

Jan 1, 1977

By A. Gene Collins

The Bureau of Mines conducted a research study of the geochemistry of the Smackover Formation to determine what geochemical relationships are useful in exploration for and production of oil and gas. Samples of oil, gas, brine, and rock were collected and analyzed. The oilfied brines were analyzed by methods recommended by the American Petroleum Institute and by tentative methods of the American Society for Testing and Materials. The crude oils were analyzed by Bureau of Mines methods; the gas, by Bureau of Mines methods; and the rocks, by wet-chemical, atomic absorption, and neutron activation methods. The results were correlated and interpreted, and several geochemical relationships useful in exploration and production were found. These include the type and class of brine, organic constituents in the brine, redox potential, in situ temperature and pressure of brine, degree of sulfate and carbonate saturation of brine, and halide concentrations in the brine.

Jan 1, 1974

By Hal H. Engel

This publication was written in response to numerous requests for information about the Federal Bureau of Mines' "Demonstrated Lecture on Flame Propagation and Permissible and Explosion-Proof Electrical Equipment." The requests came principally from: (1) Persons wanting to know more about the demonstration before requesting it for groups they represented; (2) persons wishing advance information to help publicize a meeting where the demonstration was to be given; and (3) members of audiences desiring something to help them remember the salient points, facts, and figures presented during the lecture and demonstration. The purpose of the demonstration that accompanies the lecture is to show: (1) Variations in flame speed and pressure at various percentages of flammable gas within the flammable range; (2) effect of flame speed on the "pressure piling" within the area confining the mixture; and (3) the application of flame speed and pressure piling to the combustion of surrounding gas and to the design and maintenance of electrical equipment used in hazardous locations.

Jan 1, 1960

By Philip C. Good

Unweathered low-grade calcareous phosphate rock of about 20 percent P205 grade was beneficiated by a procedure in which contained carbonates were decomposed by calcination at about 1,000° C. On quenching the hot calcined rock in water, major impurities passed into a slime phase which was mechanically separated from a coarser concentrate fraction. Phosphate rock of two major types was beneficiated in batch-scale studies yielding concentrates containing 31.3 to 38.5 percent P205 at recoveries ranging from 54.8 to 86.0 percent. The samples were from two major deposits in India. Processing information gained was utilized in extending the work to a continuous-flow system, processing phosphate rock at rates up to 157 kilograms per hour. Superphosphate exceeding 16 percent water-soluble P205 was prepared from concentrate derived from continuous-flow processing.

Jan 1, 1976

By H. Kenworthy

Laboratory experiments were conducted on several materials to determine their suitability for the production of mineral wool. By blending raw charges in the proper proportions and in some instances by adding lime, acceptable wools were made from samples originating in Alaska, Florida, Texas, and Virginia. It was shown that satisfactory wools can be produced from many kinds of raw materials if the ratios of acidic and basic constituents are properly maintained. INTRODUCTION The Federal Bureau of Mines has facilities at the Mississippi Valley Experiment Station, Rolla, Mo., for examining and testing mineral-wool raw materials. Samples are evaluated through small-scale wool-blowing experiments, aided by petrographic, chemical, and physical analyses of the raw materials and finished wools. When enough experimental data have been accumulated they are made public through Government reports and periodicals. This report of investigations follows that published in 19513/ and presents test data on samples received and examined since 1951.

Jan 1, 1956

By S. L. May

Tantalum and columbium can be extracted from several of their ores or concentrates by chlorination procedures. Direct chlorination of high-grade minerals in the presence of carbon at temperatures between 500° and 800° C will extract up to 99 percent of the tantalum and columbium. Metallurgical beneficiation of low-grade source materials by carbothermic reduction produces a ferroalloy that is amenable to chlorination at a temperature of 500° C. Over 90 percent of the tantalum and columbium can be recovered.

Jan 1, 1965

By John A. Breslin

Size distributions and concentrations of particulates emitted from diesel engine exhausts were measured with cascade impactors. Samples were taken from the exhaust of two types of engines using three types of fuel and operating under five different engine speed and load conditions. The measured mass median diameters of the diesel particulates were typically about 0.3 um. There was no significant difference in mass median diameter between engines or fuels and only a slight dependence on operating mode. Concentration measurements ranged from 14.2 to 250.9 mg/cu m, and calculated mass outputs, from 52 to 3,443 mg/min. Significant differences in mass output were found between engines, fuels, and especially between different operating modes. The quantity of clean dilution air that would be required to reduce the particulate mass concentration below the 2.0 mg/cu m respirable dust standard for coal mines was greater than the dilution air required to meet the standards for noxious gases for both engines tested.

Jan 1, 1976

By Knox Van Dyke, Vincent Castranova, Lixin Wu, Mark J. Reasor, James M. Antonini

"One of the proposed mechanisms involved in the pathogenesis of silicosis is that inhaled silica dust activates a ""respiratory burst"" in pulmonary phagocytes, such as macrophages and neutrophils. This increase in oxidative metabolism results in enhanced generation of reactive oxygen species which if produced in excess, would overwhelm natural defense mechanisms and cause damage to the lung parenchyma. This damage would then result in scarring, fibrosis, and decreased gas exchange.Weiss and LoBuglio' have listed several oxygen species produced by phagocytes which may be involved in cellular injury. These oxidants include superoxide anion, hydrogen, peroxide, hydroxyl radical, and hypochlorous acid. Superoxide anion (0;) is generated from molecular oxygen by the plasma membrane bound enzyme NADPH oxidase according to the following reaction:Once generated, superoxide anion can form hydrogen peroxide:In the presence of myeloperoxidase and halide, hydrogen peroxide can form hypochlorous acid:Superoxide and hydrogen peroxide can also form highly reactive hydroxyl radicals. Hydroxyl radicals can be generated slowly by the Haber-Weiss reaction:In addition. hydroxyl radical production can be catalyzed via the Fenton reaction:Hydroxyl radicals can also be generated from the reaction of superoxide and hypochlorous acid as follows:Recent investigations suggest that, in addition to the reactive oxygen species discussed above, nitric oxide may be a potential mediator of silica-induced toxicity.2-4 Nitric oxide (NO') can be generated by the cytosolic enzyme nitric oxide synthase according to the following reaction:NO synthase exists in two forms. i.e.. a constitutive. Ca2+-calmodulin-dependent form and an inducible. Ca2+-calmodulin-independent form. In pulmonary phagocytes. the activity of the constitutive form of NO synthase is low. However. NO synthase can be induced in macrophages and neutrophils by a variety of stimulants such as lipopolysaccharide. interferon y. chemotactic peptide, platelet activating factor, or leukotriene B4.3.5Once generated. nitric oxide can combine with superoxide anion to form peroxynitrite as follows:Peroxynitrite is a potent oxidizing agent. In addition, peroxynitrite can form peroxynitrous acid. which in turn can produce hydroxyl radical and nitrogen dioxide (all of which exhibit strong oxidizing potential) by the following reactions:Oxygen metabolites have been shown to cause lung damage in vivo.6 Such damage includes edema. leakiness of the alveolar endothelial/epithelial barriers, and airway constriction.7 Superoxide and hydrogen peroxide have been associated with membrane damage and cell lysis.8 These oxidants have also been associated with alteration of cytoskeletal structures at cell-cell junctions and elevation of transepithelial conductance in cultured monolayers.9 Macrophages or neutrophils can be stimulated by bacteria or phorbol myristate acetate to produce sufficient oxidant levels to lyse lymphoma cells.10 This cell killing is inhibited by catalase but is unaffected by superoxide dismutase. hydroxyl radical scavengers. or azide. i.e., an inhibitor of peroxidase. This implicates hydrogen peroxide as the active oxidant. Similarly. Weiss et al.11 have reported that hydrogen peroxide is critical in the death of cultured endothelial cells due to neutrophil activation. In addition. hydroxyl radicals generated by monocytes have been associated with cell injury.12 Lastly. peroxynitrite has been shown to oxidize sulfhydryl groups and to inactivate proteinase inhibitor making the lung more susceptible to damage caused by phagocytotic enzymes.' Therefore. a strong case can be made that activated pulmonary macrophages and neutrophils are capable of causing oxidant injury. This chapter presents in vitro and in vivo data indicating that silica is associated with the production of reactive oxygen species from these pulmonary phagocytes."

Jan 1, 1998

By Frank J. Cservenyak

Curtailment of bauxite importation by enemy activities during World War II focused attention on the necessity of developing domestic deposits of aluminous materials. Large quantities of aluminum ores such as kaolin, siliceous bauxites, high-iron bauxites, anorthosite, and diaspore clays are available but not readily amenable to Bayer processing because of excessive impurities. The Bayer process, which is the only commercial method in use in the United States for producing metallurgical-grade alumina, requires a high Al2O3 bauxite relatively low in SiO2 and Fe2O3. The Bureau of Mines was charged by Congress to investigate processes for the production of alumina from these low-grade ores. One part of the program was an investigation, in the laboratory and pilot plant, of the recovery of alumina by the lime-soda sinter process. Ores comprising kaolin, diasporic clays, anorthosite, and siliceous bauxites have been investigated and studied in the laboratory and pilot plant, and a series 'of reports covering these investigations has been prepared.

Jan 1, 1948

By James W. Miller

An investigation was begun by the Bureau of Mines in 1948 to determine the preparation characteristics of American coals. Results of the investigation were planned to be reported on a county basis and from the data developed, to determine: (a) Which coals either as mined or after beneficiation by conventional preparation are chemically suitable under present standards for producing metallurgical coke; (b) Which coals require special and more intensive treatment in preparation than is now practiced; and (c) Which coals cannot be considered potential sources of metallurgical coke, regardless of preparation. This report is one in this county series that describes the preparation characteristics of the coals of Perry County, Ky.

Jan 1, 1956

By G. S. Scott, G. W. Jones

"INTRODUCTION An important phase of the accident-preventing program of the Bureau Mines is the determination of the explosion hazards of various combustible gases, vapors, and liquids encountered in mining and allied industries and the development of methods of eliminating or mitigating them.Recently, isobutane has become a commercially important raw material in the production of aviation gasoline by the alkylation process. 4/ in which isoparaffins are combined with olefins to give higher molecular weight compounds of branched-chain structure.Because of the anticipated commercial importance of isobutane in industry, it has been deemed necessary to study and determine its general explosion haz¬ards. This report gives its limits of inflammability, minimum ignition temper¬atures, and the amounts of nitrogen and carbon dioxide required to render isobutane-air mixtures noninflammable."

Jun 1, 1947

By J. S. Hansen

In support of its objective to conserve mineral resources by minimizing premature failure of materials, the Bureau of Mines conducted a cooperative study with the U.S. Department of Energy on the erosion and abrasion resistance of hard materials for valves in coal conversion systems. This report describes a newly developed erosion-testing apparatus and presents data on the erosion resistance of over 200 materials. Erosion resistance of most metals was comparatively low. In contrast, ceramics and cermets such as B4C, WC, SiC, Si3N4, and TiB2, when fabricated to minimize porosity, displayed greater than five times the erosion resistance of metals. Coatings such as boron diffused into Mo and WC, chemical-vapor-deposited TiCN, and electrodeposited TiB2 were highly erosion resistant if applied in thicknesses ranging from 60 to 75 µm. Erosion resistance of cemented carbides was inversely related to metal binder content.

Jan 1, 1979

By R. M. Gammell

"INTRODUCTION The Farmer prospect was examined by W. R. Green, an engineer of the Bureau of Mines, in June 1944. As a result, studies of this property were included in a general preliminary investigation of the Etevens County lead-zinc deposits by the Bureau in 1945. The exploratory work was designed chiefly to supplement the surface examination by determining the nature of the mineralization below the zone of oxidization. The results of the small-scale diamond-drilling program undertaken at the property are presented in the following report.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization our resources to the end that they make the greatest possible contribution to security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work and prepares the filial report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests."

Mar 1, 1947

By Michael T. Nigbor

The Bureau of Mines assisted the Rocky Mountain Energy Co. in a pilot-scale in situ leaching experiment at Casper, Wyo., to determine if sulfuric acid can be used as a cost-effective alternative lixiviant (leachant) for uranium in situ leaching. This experiment, which lasted more than 2 years, is the first fully documented pilot-scale operation in which the leaching-restoration cycle was completed using sulfuric acid instead of the more common carbonate-bicarbonate leachant This report describes activities at the experimental site, presents extensive geochemical data from startup to site restoration, compares laboratory and field experiments, and discusses the environmental aspects of acid leaching. The data showed that sulfuric acid is apparently an effective leaching solution. Three to five grams of acid per liter of ground water resulted in a production solution grade of 80 to 100 ppm uranium. Restoration was successful, but required extended flushing. The pH was the last chemical parameterto return to baseline, requiring about 350 days. This was longer than was predicted in laboratory simulations. The data also showed that mobilization of toxic elements such as selenium, arsenic, radium, thorium, and molybdenum stayed within reasonable limits and quickly fell back to preleach concentrations during restoration.

Jan 1, 1982

By R. A. Kearns

To enable the mining industry to be kept informed as to the availability of equipment developed by mining equipment manufacturers in their constant endeavor to keep a step ahead of changes in mining techniques, the Bureau of Mines periodically issues lists of equipment approved subsequent to the last previous listing. The present list covers those approvals issued during calendar years 1953 and 1954. It supplements Bulletin 543, Permissible Mine Equipment Approved to January 1, 1953. The procedure established in Bulletin 543 of numbering items in each category consecutively to indicate the chronological order of the approvals has been continued in this circular. Information on approvals issued later than January 1, 1955 may be obtained by referring to Coal Age, a monthly magazine issued by the McGraw-Hill Publishing Co.

Jan 1, 1955

By Roy C. Bartholomae

An accurate characterization of the vibration environment and a vibration qualification test derived from it will be a very useful tool for manufacturers of instrumentation for use on underground coal mining equipment. Recognizing this, the Bureau of Mines sponsored a study wherein vibration levels were measured on mining equipment to form a basis for developing the required vibration test. The data base was composed of 160 samples taken at different positions on a variety of underground machinery. The data were analyzed and presented in a format typical of military vibration qualification tests. The form was shown to be virtually identical to the swept sine test envelope specified in MIL-STD-810B for tracked vehicles.

Jan 1, 1982

"MASSACHUSE'M'S INSTITUTE OF TECHNOLOGYBOLSAITIS, PETERMassachusetts Institute of TechnologyDepartment of Mineral Engineering77 Massachusetts AvenueCambr1dge,MA 02130(614) 253-5069ELLIOIT, JOHN F.Massachusetts Institute of TechnologyDepartment of Mineral Engineering77 Massachusetts AvenueCambridge, MA 02130(617) 253-3305RING, TERRYDepartment of Materials Science and EngineeringMassachu5etts Institute of TechnologyCambridge, MA 02130(6117) 253-4299"

Jan 1, 1988

By John Nagy

Large-scale tests in the U.S. Bureau of Mines Experimental Coal Mine show that the explosion hazard of coal dust on shuttle-car roadways can be con-trolled by proper application of water, dry rock dust, a saturated solution of ammonium phosphate, or mixtures of water or the water-phosphate solution with rock dust. The experiments were made with loadings of 1.0 and 5.0 pounds of mine size coal dust per linear foot of entry, and with a 3-or 4-inch-thick layer of coal rubble on the floor, The data from the tests with mine-size coal and rubble are comparable. The water contents of the dust loading were determined from samples collected just prior to initiation of a gas-air mixture in an ignition zone at the face Dust samples were collected 1 inch deep from the coal-rubble deposit. One experiment was made with the dust in the coal rubble bound with latex applied as a water solution by spray. The binding action was inadequate and explosion propagation was obtained.

Jan 1, 1970