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By C. B. Daellenbach

A prototype particulate size analyzer system was developed that would rapidly determine size distributions of homogeneous and two-mineral materials in the 74-micrometer (200-mesh) to 7-micrometer size range. The system sizes particles in a series of hydrocyclone elutriation steps and senses the weight of the five sized fractions by nuclear attenuation techniques. Size distribution of materials was determined from experimentally developed mathematical relationships that existed between particulate weight and the measured transmittance of gamma rays from an Americium-241 source. In the developmental phases, size distributions of three minerals (quartz, magnetite, and hematite) and a laboratory prepared two-mineral mixture of quartz and magnetite were accurately determined by the prototype system. In later stages of the investigation, semiconcentrates, an intermediate magnetic product from a taconite plant, were evaluated. Using 25-gram feed samples of this industrial material, the analyzer system was found to predict weight percentages for individual size fractions with an accuracy of ±0.85 percent or better at a 95-percent confidence level.

Jan 1, 1974

By D. W. Butner

This report is concerned with the conditions affecting the methods and costs of mining phosphate rock in that part of the western phosphate field that is in Bear Lake and Caribou Counties in southeastern Idaho ( see fig . 1) . The area was selected because it contains most of the known phosphate reserve and because its geology has been studied more extensively than that of other sections . Deposits of phosphate rock on public land may be leased from the Government under the terms of the Mineral Leasing Act of 1920 , subject to the regulations of the Bureau of Land Management . Public interest in phosphate production is growing , as shown by an increasing number of applications for leases . Two mines are being operated steadily for the production of phosphate rock by companies that have also the necessary processing plants for the manufacture of fertilizer . Total western phosphate - rock production in 1947 is reported by the Economics Statistics and Division of the Federal Bureau of Mines to have been 1,193,000 long tons , mined in Idaho , Montana , and Wyoming . The average grade was 30.7 percent of contained phosphorus pentoxide (P205 ) ; the average value at the mines was $5.67 per long ton . Idaho contributed 905,000 tons , or somewhat more than 75 percent of western production . Western fertilizer plants took 23 percent of total production; 76 percent was exported . Strip mining accounted for 75 percent of the Idaho tonnage; the remainder was stoped from underground workings . Rock must contain a minimum of 30 percent P205 to be commercially useful for the production of superphosphate fertilizer by current acid treatment methods . Research by corporations and Government agencies has been directed toward the use of lower - grade ore . So far , only by smelting can rock containing as little as 25 percent P205 be used economically . Any development of processing or use pattern that would render the mining of , say , 20 percent rock profitable would have important effects in reducing the unit cost of mining . In the search for metallurgical improvements , consideration should be given to the saving of valuable components of the rock, such as vanadium and fluorine , both of which are present in the beds .

Oct 1, 1949

By J. S. Tosh

The Federal Bureau of Mines has investigated the equilibrium of the system potassium carbonate (K2C03) potassium bicarbonate (KHCO3) potassium bisulfide (KHS) carbon dioxide (C02) hydrogen sulfide (H2S) water (H20). Partial pressures of hydrogen sulfide, carbon dioxide, and water vapor were measured at 70° to 130° C. over solutions of 20-, 30-, and 40-percent-equivalent potassium carbonate containing from 20 to 3,000 grains of equivalent hydrogen sulfide per gallon of solution. This study was made to obtain equilibrium data for evaluating the feasibility of using solutions of hot potassium carbonate for removing, hydrogen sulfide from gas mixtures. The equilibrium partial pressure of hydrogen sulfide may be correlated with the ratio of the molal concentrations of the solutes (KHC03) (KHS)/ (K2CO3). The relationship is shown graphically for the 30- and 40-percent solutions. Once this ratio is determined, the partial pressure of hydrogen sulfide can be obtained from the curves. The equilibrium data show that effective removal of both carbon dioxide and hydrogen sulfide can be achieved simultaneously with hot solutions of potassium carbonate.

Jan 1, 1960

By John J. Mulligan

Coalbeds were discovered in outcroppings of the Beacon group of sediments on the north end of the Willett Range ( altitude 77 ° 11 ' S , longitude 160 ° 20 ' E ) , Victoria Land , Antarctica , in December 1960 during an investigation undertaken as part of the U.S. Antarctic Research Program under the auspices of the National Science Foundation . Three separate exposures of coal or coaly material were found . Two of the exposures contain , respectively , eight and four beds of hard , compact , finely banded attrital coal ranging in thickness from 8 feet downward to a few inches , and reported to range in rank from mediumvolatile bituminous to semianthracite . The coals are associated with carbonaceous shales containing an abundant assemblage of fossil plants resembling those associated with the Permian coals of Australia and other Gondwana areas . The third exposure , apparently somewhat higher in the stratigraphic sequence , contains only coaly plant fragments scattered through a thin conglomerate and overlying sandstones . A sandstone bed that overlies these coal - bearing sandstones contains abundant logs and fragments of silicified wood . Preservation of features is poor , but one segment of a silicified stem suggests comparison with Rhexoxylon , a gymnospermous tree that usually is considered indicative of Triassic age . The Beacon sediments in this area have been invaded , broken , and uplifted by a massive series of diabase sills and dikes greater in volume than the intruded sediments . The heat emitted by these intrusives must have advanced the metamorphic development of the coals . However , there is no evidence of alteration to graphite , and coal found in direct contact with a diabase sill contains no vesicles or other usual evidences of natural coking . Either the pressure of overlying rocks inhibited the development of coke , or the coals had been metamorphosed beyond the coke forming stage before the igneous intrusion .

Jan 1, 1963

By D. H. Carlson

The U.S. Bureau of Mines and Michigan Technological University (MTU) are collaborating to develop an apparatus for measuring diesel tailpipe emissions in underground mines. A tailpipe emissions measurement apparatus (EMA) is described that dilutes diesel exhaust and measures the concentrations of diesel particulate matter (DPM), CO, CO2, NO, and NO2 at known dilution ratios. The EMA was evaluated by side-by-side comparison of its measurements with those by laboratory-grade instruments. Concentrations of CO and CO2 measured by the EMA were usually within ± 14 pct of concentrations measured by laboratory-grade instruments for CO and ±20 pct for CO2. EMA¬ measured DPM concentrations were, on average, 29 pct lower than those measured by laboratory-grade instruments, with the differences being fairly consistent. The CO and CO2 differences are related to the method of calculating the EMA's dilution ratio, and the difference in DPM concentrations is attributed to thermophoretic and/or condensation losses related to the EMA's unheated sample probe. Preliminary analysis of data obtained with a heated sampling probe and modifications in the sampling procedures have indicated reduced variability in DPM and in the calculated dilution ratios.

Jan 1, 2010

By R. V. Higgins

As part of a study of application of the Buckley-Leverett method to an analysis of oil-reservoir performance covering a wide range of relative permeabilities and oil saturations, a method has been devised for quickly deter-mining average water saturation at breakthrough from relative permeability data. The base for the relative permeability used in the report is either the permeability to air or the effective permeability to oil at the irreducible water saturation. The permeability to air also was used because of the large backlog of air permeabilities available to reservoir engineers. The basic data were calculated by an electronic computer and are presented in a single graph from which the point of breakthrough may be obtained. In this study the water saturation at the beginning of the depletion is the connate or interstitial or irreducible water saturation. These water saturations are considered to be synonymous and to have a practical value.

Jan 1, 1960

By Richard N. Spencer

Electric-furnace smelting for simultaneous recovery of zinc spelter and lead bullion from complex lead-zinc sinter was investigated. Reduction of lead and zinc was satisfactory. Condensation of lead and zinc vapor to pyrophoric metal powder in a water-cooled, shock-condensing system produced excellent recoveries. Metal-splash condensation to produce zinc spelter was unsatisfactory. Special smelting experiments differentiated the effects of several smelting parameters on zinc metal recovery. The principal cause for unsatisfactory zinc metal recovery was transfer of iron to the condenser and subsequent degradation of zinc in a mixture composed of lead and an iron-zinc intermetallic compound. Limitations of the process were determined. Slag-resistance open-bath electric smelting of complex lead-zinc sinter is not considered feasible.

Jan 1, 1967

By Rollie P. Dobyns

The K.M.A. reservoir was discovered to be oil bearing at a depth of 3,719 feet on March 11, 1931. Extensive development, however, was not begun immediately, because the discovery well had a low initial daily oil production, and market conditions for oil were unfavorable. Development of the field progressed slowly for the next 6.5 years. In the latter part of 1937, a wildcat well approximately 2 miles southwest of the discovery well was drilled on a magnetometer high and completed with an initial flowing production of 2,018 barrels of 430 A.P.I.-gravity oil in 12 hours. Rapid development of the southwestern part of the K.M.A. field was begun immediately and continued until over 700 wells were drilled and approximately 12,500 acres proved oil productive. Because of the large size of the entire K.M.A. field, this report is limited in scope to the southwestern part only, and the discussion that follows pertains to this area only. The closing date for production statistics is August 1, 1949. The K.M.A.? structure is a complex anticline having a maximum closure of 250 feet, and the K.M.A. formation is composed of sediments that grade from limestone through sandy lime and limy sand to sandstone with thin streaks of shale. Two "distinct members of the K.M.A. formation, zone I and zone II, are oil productive. Core analyses indicate the average porosity to be 16.5 percent for zone I and 16.1 percent for zone II. A relationship was established from core data, which showed the correlative permeabilities to be 42.1 millidarcys for zone I and 39.5 millidarcys for zone II, whereas the arithmetical averages of the permeabilities were 84 millidarcys for zone I and 216 millidarcys for zone II. Connate-water saturations were 17.5 percent for zone I and 20.0 percent for zone II. The porosity-saturation method, using a thickness-correction factor, was employed to calculate the volume of 168.1 million barrels of stock-tank oil initially in place in the reservoir. Analyses of the reservoir oil indicate that, although the initial reservoir pressure was 1,750 p.s.i., the original reservoir oil was saturated to only 1,300 p.s.i., at which pressure 1 barrel of stock-tank oil contained 525 cubic feet of ea~ in solution.

Jan 1, 1952

By L. Keith Hudson

The purpose of this study is to provide data that demonstrates that the Alcoa flash calciner design can be used for the decomposition of AlCl3?6H2O to A1203. Heat and material valance data for calcination provides data on the partial pressure of HCl in the off-gases. Experimentally determined data for the HCl partial pressure, over solutions expected in producing alumina from clay by the hydrochloric acid process, show that HCl can be absorbed from the off-gases into process solutions to effect crystallization of AlCl3?6H2O.

Jan 1, 1979

By E. O. Wagner, Manuel Gomez, W. S. Landers

The Bureau of Mines studied coking rates of a special Columbia - Geneva six - coal blend to establish the effect of the coking rate on coke properties . The tests were conducted in a 500 - lb , 14 - in experimental slot oven at essentially constant conditions of blend composition , size distribution , surface moisture content , and bulk density . The coking rate was varied as a function of oven flue temperature . Coking rates within the range of 0.56 to 1.35 in/hr were achieved . Increase in the coking rate decreased the size of the coke . The stability factor of the coke showed no significant change with coking rate until coking rates greater than 1.0 in/hr were reached , after which a decrease in the stability factor was observed . The apparent specific gravity increased to a maximum value at coking rates approaching 1.1 in/hr and decreased sharply with further increase in the coking rate . Coke parameters correlated well with the coking rate .

Jan 1, 1963

By Earl R. Maize

Epoxy and polyester-type resins were injected into coal-mine roof strata of the thick Freeport coal seam in Allegheny County, Pa., at test sites in roof that had been exposed several weeks, in newly exposed roof, and in strata over solid coal. Test results indicate that the method of strengthening bituminous-coal-mine roof by injecting a bonding material into the roof strata can be developed into a safe, efficient support system. If roof bonding will become a standardized method of roof support and reinforcement or if it can be effective when used with other types of roof support can be determined only by extensive experimentation in various coal beds. Observations and conclusions are shown at the end of this report.

Jan 1, 1959

By J. B. Gayle

In a modern blast furnace, production depends, to a large extent, on the rate at which the furnace gases can be forced through the charge. Since these gases must make their way through the voids between particles of coke, ore, and limestone, the size and size distribution of the stock-column materials are of considerable importance. Also, because the coke pieces support the weight of the overburden and provide the majority of the voids through which the gases pass, their ability to withstand the shattering and abrading forces to which they are subjected should be related to the maximum obtainable production for any particular furnace. Although the wide acceptance of this point of view is indicated by the ever-increasing demand for stronger and more uniform blast-furnace cokes, economic considerations demand that a quantitative evaluation of the relation between coke quality and blast-furnace performance be made available to the industry at the earliest possible date. The following studies of size-distribution patterns and breakage processes were, therefore, conducted as a part of a preliminary investigation intended as a basis for future studies of the relation between coke quality and blast-furnace performance. The major findings may be summarized as follows: 1. New evidence for the presence of two independent distributions of sizes in run-of-oven cokes has been obtained, and a method for characterizing and estimating the relative importance of the individual distributions has been demonstrated. This method has also been used to study the different types of degradation taking place during the tumbler test.

Jan 1, 1954

By B. J. Moore

This publication contains analyses and related source data for 352 natural gas samples from wells and pipelines in 18 States and 5 foreign countries. All of the samples were obtained and analyzed during calendar year 1974 as a part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economics. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4862 and 576.3 The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the public in general. Sixteen previous publications have presented the results of 10,479 gas analyses prior to 1974. The first three, Bulletins 486,4 576,5 and 617,6 contain analyses and related source data on

Jan 1, 1975

The Bureau of Mines is establishing design criteria for effective roof support systems and is developing technology to improve mine planning and design. Geologic studies, surface and underground mine monitoring, and laboratory evaluations were conducted. The seven papers in this proceedings Information Circular present results of several investigations. Addressed are problems existing in both longwall and multiple-seam mines. Discussions include the effect of dewatering at a longwall mine site in the Pittsburgh coal seam and the effect of chain pillars on subsidence. Other results are measurement and characterization of longwall rock mass movement and an integrated design for stability in multiple-seam mining.

Jan 1, 1987

By Philip W. Holland

The U.S. Bureau of Mines has designed and built an inexpensive, weatherproof, temperature-controlled cabinet to provide temporary housing for analytical instrumentation. The cabinet consists of an inverted Styrofoam ice chest, an electric fan for air circulation, and a proportional temperature controller equipped with a thermistor sensor and a light bulb as the heater. The cabinet provides a constant-temperature environment for a moisture analyzer and a strip chart recorder when outside temperatures range from -SO to 21° c.

Jan 1, 1993

By Gerald T. Homce

A system capable of monitoring a mine electrical power system to detect incipient electrical component failure could significantly improve power system safety and availability. The U.S. Bureau of Mines funded a contract with The Pennsylvania State University (Penn State) to establish the theoretical and technical framework for such a system. This report briefly outlines the contract, reviewing related Bureau and Penn State work prior to its award, and describes support work carried out by the Bureau. The main focus of the report is on research efforts by Penn State and subsequent results. An existing algorithm for incipient-failure detection and classification was studied, and recommendations are made to improve its performance. In addition, mathematical models of cable-connected motor systems and deteriorating motors were developed and implemented on computers. These models and laboratory tests were used to study and document relationships between component deterioration and electrical terminal effects. The project was supported by the U.S. Navy and the nature of its interest in the application of failure prediction techniques is also included.

Jan 1, 1989

By R. R. Sayers

Although the attention of those interested in diseases peculiar to mining as teen focused recently on one duct disease - silicosis - other respiratory diseases may cause more suffering and economic loss. The increased incidence of these diseases usually is attributed to exposure to abnormal air conditions underground, such as sudden changes from high to low temperatures, excessive dust, and noxious gases. The principal respiratory diseases to which the mine is subject axe bronchitis, influenza and pneumonia, pulmonary tuberculosis, anthracosilicosis, and. silicosis. Although the mortality statistics in some of the tables included in this paper are old they have been corroborated by later, lees complete data Bronchitis Bronchitis is en inflammation of the bronchial tubes due, among other causes, to the inhalation of irritants such as dusts (organic and inorganic). Occupations that entail exposure to atmospheres polluted, by irritating gases carry with them the risk of bronchitis. According to Collie (1), it cannot be distinguished clinically from bronchitis occurring among the general population, and its association with tae inhalation of dust or gases usually is unrecognized.

Jan 1, 1941

By J. L. Kohler

The final report for Phase II of Bureau of Hines Contract J0134025 concerns the research and development of sensitive ground-fault relays for dc utilization systems in mining. Sensitive relaying employs very low pickup levels such that, when used in conjunction with very high resistance grounding, the exposure of a human to ventricular fibrillation is significantly reduced. To delineate the desired relay characteristics, the report begins by reviewing previous research in this area. A theory for the saturable transformer used to sense the fault current is presented. The design of the ground fault relay is described in sufficient detail that it may be duplicated. Test procedures and results are given. Finally, conclusions and recommendations related to Phase II are presented.

Jan 1, 1986

By Michael G. Zabetakis

The process of ?gasfreeing? has been defined3/ as "* * * the removal of oil and vapors from tanks, pipelines, and compartments to render such spaces safe for the intended work," Generally, part or all of a vessel is gasfreed for one of several reasons: Periodic cleaning; tank inspection or repairs; shipyard overhaul or major repairs; or change of cargo, Curing the gas- freeing, flammable or explosive4/ mixtures (mixtures through which a flame can propagate after ignition by an open flame, heated object, electrical charge, or other means) may be produced. These mixtures create an explosion hazard, as the pressures produced after their ignition are often great enough to completely demolish the vessel and kill all those aboard, This paper outlines a study by the Federal Bureau of Mines of the gas explosion hazards likely to be encountered while gasfreeing a vessel compartment. To better understand these hazards it will first be necessary to review the language used in gas- explosions work. This language is considered in the following sections. Inert gases such as carbon dioxide, nitrogen, water vapor, and others can be used to decrease the range of combustible-vapor concentrations in which flammable mixtures are formed. Sufficient quantities of such gases can often be added to cause a mixture that originally was flamable to become nonflammable. Unfortunately, the use of water vapor in this application is complicated by the fact that elevated temperatures are required to keep the water in the vapor state. In practice, it may be difficult to maintain these elevated temperatures throughout the space (such as a cargo tank) to be inerted for any length of time. Accordingly, where other inert gases are not available, it may be desirable to gasfree a Lank by using heated air. To do this, the combustible vapors should be flushed as quickly as possible from the space to be gasfreed. In a properly designed system, large tanks were gasfreed with a littlee as 6 volumes of air per volume of tank capacity.

Jan 1, 1961

By Joseph J. Wallace

The 1952 Annual Report of the West Virginia Department of Mines lists seven beds that are being mined in Mingo County, of which the Cedar Grove is the most important. The Cedar Grove, Alma, and Coalburg contain the largest remaining known reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of coal in place, are estimated at 3,007 million short tons as of January 1, 1953. Of this total, 2,396 million short tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1954