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By Arden D. Fugate

This work was conducted to determine a feasible process for converting siliceous fluoride offgases to a commercially usable product. The offgases were generated by pyrohydrolytic defluorination of low-grade fluorspar in a gas-fired rotary kiln, and fluorine was collected as a hydrofluoric-fluosilicic acid. A silicon-free fluoride solution for further processing was then produced by neutralizing the acidic scrubber solution with anhydrous ammonia, silicon being separated as orthosilicic acid. Ninety to ninety-nine percent of the fluorine originally present remained in solution as ammonium fluoride. Silicon was also separated from synthetic fluosilicic acids, having F-to-Si weight ratios ranging from 3.50 to 14.3. The solutions below a ratio of 4.06, the F-to-Si ratio of H2SiF6, containing dissolved silicon were desiliconized as completely as those containing less than the stoichiometric quantity of silicon. An electrolytic-grade cryolite was recovered from the ammonium fluoride solution by reacting with either sodium aluminate or alumina trihydrate and sodium hydroxide. A product containing 97 to 100 percent of the fluorine, represented by Na3A1F6, was recovered, and 94 to 99 percent of the theoretical yield was realized.

Jan 1, 1963

By Deborah A. Kramer

An economic and technical evaluation of a proposed process to recover alumina by leaching calcined kaolinitic clay with sulfurous acid is presented in this Bureau of Mines report. After the insoluble portion of the clay has been removed by leaching, monobasic aluminum sulfite is precipitated from the pregnant leach solution by partial hydrothermal decomposition. Further heating completes the decomposition to an impure alumina hydrate. This intermediate is purified in a modified Bayer process, which includes dissolving the alumina hydrate in a caustic solution at high temperature and pressure, then decreasing the temperature and pressure to precipitate alumina trihydrate. Calcining the trihydrate produces the alumina product. A cost estimate was prepared for a plant producing 1,000 tons of alumina per day, 350 d/yr. The estimated operating cost is approximately $475 per ton of alumina. This is substantially higher than a comparable estimated operating cost for the Bayer process of $250 per ton of alumina. The proposed process does not appear economically attractive, even as a method to modify a current Bayer processing plant to use a kaolinitic clay feed. High capital costs and high energy requirements make the process prohibitively expensive.

Jan 1, 1983

By Clayton M. Rumsey

In 1984, the U.S. Bureau of Mines conducted a mineral survey of a 26,598-acre study area which includes the 23,702-acre Mt. Limbo Wilderness Study Area (NV-020-201). The study area is 65 miles northeast of Reno, NV, and is underlain mainly by Cretaceous granodiorite that comprises the Selenite Range. Tertiary basalt, rhyolite, and sedimentary rock as well as Quaternary alluvium and lake deposits are exposed near the study area boundary. Mines just north of the area in the Hooker mining district produced tungsten ore in the 1940's and 1950?s. Similar deposits are not known in the study area. Disseminated gold is in sinter about 6 miles west of the study area and at several other locations regionally.

Jan 1, 1986

By Ben E. Lindsly

The study of "bottom-hole samples follows in natural sequence the study of samples obtained under high pressures at the well heads of flowing wells. The principal object of this phase of gas-solubility research, started actively in January, 1930, was to gain a more accurate knowledge of the physical and chemical characteristics of the oil-gas mixtures that exist in natural reservoirs.. In possession of actual data regarding the condition of the oil; the quantity of gas liberated from solution upon dimunition of pressure; and the relative volumetric proportions of gas to oil at various pressures throughout the flow string in a well, it should be possible to predict, with a fair degree of accuracy, That physical changes these mixtures would undergo throughout the life of a pool. Such information not only is important in designing flow strings in flowing Tells but is important also in solving problems relating to pumping efficiency and the power required for pumping. Although certain fundamental data were obtained in the study of samples taken at the well head, "bottom-hole" samples are more representative of subsurface mixtures of oil and gas because they are obtained at reservoir temperatures, and before the oil has had the opportunity of intermingling with extraneous gas; that is, gas which either was not in solution originally, or which was liberated from solution at higher pressure, and later became mixed with the original undissolved gas.

Jan 1, 1933

By Charles H. Parr

A testing program was conducted to determine the suitability and reliability of adhesives and polycarbonate lenses for extended use in luminaires in mine environments. Polycarbonates were exposed, for periods up to 36 months, to four environments including ultraviolet light, humidity, intermittent water spray, and heat of either 180°F or 407 in various combinations. Rod impact tests on the exposed lens material indicated, that polycarbonate functions well under all 180°F environments and could be used with confidence for periods exceeding the test period, for as long as ten years, with a suit) able safety factor employed in design. The specimens exposed at 240°F showed decreased toughness after 24 months' exposure. Extrapolation of these data was deemed to be risky. A 462-day compatibility test between polycarbonate and six hydraulic fluids was run on stressed PC beams. One fluid caused beam breakage in less than one day, while three caused breakage at intermediate times. Two fluids exhibited essentially no effect on the PC when compared to a control. Epoxy and silicone adhesives were tested as lens adhesives and sealants. Three epoxy combinations tested showed low and erratic failure stresses. A room-temperature-cure silicone adhesive functioned extremely well for time periods up to 36 months and temperatures u2 to 240°F.

Jan 1, 1985

By R. V. Ramani

This report is volume 1 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report contains a statement of the purpose and scope of work of the Grant, and provides an overview of the Master Design Simulator with a brief description of each subsystem. Also included is a discussion of several areas of application for the simulator.

Jan 1, 1975

By Raymond W. Hiteshue, Sam Friedman, Martin D. Schlesinger

The Bureau of Mines in cooperation with the El Paso Natural Gas Co. investigated the effect of high temperature and pressure at short residence times on the hydrogenation of a New Mexico coal to gaseous and liquid hydrocarbons . The study was made in a bench - scale semicontinuous unit at pressures of 500 to 6,000 psig , 480 ° to 1,000 ° C , and residence times of less than 1 minute to 15 minutes . Ammonium heptamolybdate was impregnated on the coal to furnish 1 percent molybdenum based on maf coal . Coal could be rapidly hydrogenated at elevated temperatures and pressures to yield large quantities of gaseous hydrocarbons and small quantities of lowboiling oils , high in single - ring aromatics . At 800 ° C and 6,000 psig and a residence time of 1 minute , the yield of hydrocarbon gas was 43 percent and of liquid hydrocarbons 9 percent , based on maf coal . With a 15 - minute residence time , the yield of gaseous hydrocarbons increased to 68 percent with a decrease in yield of oil to 6 percent . At higher hydrogen velocities , the yields of oil were much greater but contained large quantities of asphaltene . Low concentrations of molybdenum (0.01 and 0.1 percent ) or a high concentration of iron ( 1 percent ) were ineffective at 800 ° C , 6,000 psig , and short residence time .

Jan 1, 1964

By H. B. Hill

The discovery of the Oklahoma City field and its rapid development into one of the major oil-producing districts is an outstanding epoch in the history of the petroleum industry not only of Oklahoma but also of the United States. The relatively great depth to which the wells were drilled and the large initial production of high-gravity oil are of special significance. The field has boon under proration almost from the time that its development began, and many new production problems have developed out of the changed conditions of operation. The discovery well was first tested in December 1928 at a depth of 6,402 feet, with an initial production of 4,847 barrels of 38,5.° A.P.I. gravity oil, and several months later was, completed at a depth of 6,624 feet, The large initial production, the high pressure, and the large gas volume in the different horizons of the discovery well suggested the potential possibilities of gas and oil, production in formations of Pennsylvanian and pre-Pennsylvanian age.

Jan 1, 1933

By C. F. Wingquist

As part of an ongoing study to determine how the wear of mining tools affects dust generation, the Bureau of Mines has measured bit tempera-ture rise during cutting of abrasive rock. Radial bit wear-flat tem-peratures generated by linear cutting in Berea Sandstone were measured as a function of cutting depth and speed. Depths of cut (DOC) were 1/8, 1/4, and 1/2 in, and cutting speeds were 10, 40, and 80 in/s, respectively. Temperature sensing was accomplished by emplacement of a miniature thermocouple into the center of the wear flat. Temperatures observed ranged from 2000 to 5000 C. Correlation between depth and temperature was weak. Temperature increased linearly with speed at 1/2-in DOC, but data taken at 1/8-and 1/4-in DOC produced inconclusive results. The results indicated that at least for deeper cuts (1/2 in), bit temperature, and therefore wear, can be reduced by lowering the cutting speed.

Jan 1, 1987

By Charles Will Wright

This paper has been written to aid the owner of a small gold mine or prospect in preparing a report on his property for the purpose of interesting capital. If an owner can afford to do so, he should employ a mining engineer of recognized standing and experience to examine and report on his property, but many owners of small -mines and particularly of prospects cannot make the expenditure required for this. Further, many of them do not know how to prepare a description which will cover those features of a deposit on which a potential investor promises his opinion as to its worth. If such an owner is convinced that he possesses an orebody of sufficient grade and size to warrant the required expenditure for a thorough investigation and wishes to present his property to prospective investors, then the following suggestions concerning the proper way to sample his deposit, estimate the tonnage of developed and probable ore, and prepare a report may be of assistance.

Jan 1, 1933

By R. E. Coleman

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

Jan 1, 1966

By Byron E. Blair

This report describes procedures for using a high-speed camera to study blasting phenomena. Both quantitative and qualitative information can be obtained, provided that proper interpretations of the projected two-dimensional images are made. Geometrical relationships between object and image displacements are given in terms of horizontal and vertical angles of the camera optic axis with respect to the quarry face. Correction factors are given for obtaining true object displacements from image displacements in the camera film plane. The time of initial rock movement also is considered, and the control-ling factors of camera speed, scale factor, minimum increment of projection measurement, etc., are evaluated in terms of minimum time intervals. The high-speed camera and associated equipment are described, and field measurements and laboratory data analysis techniques are outlined. An analysis of a typical high-speed motion picture is made, and the application of the necessary correction factors is illustrated.

Jan 1, 1960

By B. W. Naugle

Twenty-nine sole-heated-oven expansion teats were made on 9 different coals, and apparent specific-Brevity tests were made on 12 of the resultant cokes. The coals, which ranged in dry, mineral-matter-free fixed-carbon content from 58.7 to 81.1 percent, were tested over a rather wide range of moisture content and dry-coal bulk density to determine the separate effects of these variables on linear coal expansion. The experimental data support the follow expression relating "as-tested" coal bulk density, moisture content, and linear expansion, [ER = (1-MR) (1+Et) - 1; BDt] where ER = fractional expansion at a reference bulk density of 55.0 lb. of 1 percent moisture coal per cu. ft., Et = fractional expansion at Mt and BDt, MR = reference moisture content = 0.01, Mt = moisture content, "as-tested", BDR = reference bulk density = 55.0 lb. per cu, ft., BDt = bulk density, "as-tested", 1b. per cu. ft.

Jan 1, 1957

By Peter D. Lohn

The Bureau of Mines conducted both laboratory and field investigations to study the effectiveness of medium-pressure (up to 30,000 psi) water jets in controlling the generation of airborne respirable dust during the hydraulic fragmentation of coal. Laboratory studies were conducted at the Farmington High Energy Test Site of the Twin Cities Mining Research Center, and field studies were carried out at the Humphrey No. 7 mine, Mount Morris, Pa., in the Pittsburgh coalbed. The water jets were produced by commercially available triplex pumps. The dust samples were collected by midget impinger samplers, and analyzed by electronic and optical counting techniques. Respirable dust concentration for a full-scale production model was projected at below 2 mg/m3, the maximum exposure allowed by the Federal Coal Mine Health and Safety Act of 1969.

Jan 1, 1975

By W. K. Sawyer

Resistivity, porosity, permeability, and saturation data were obtained on core samples from the Big Injun, Clinton, Gordon, Bradford Second and Third, and Venango Second oil sands and formation factor-porosity relationships were derived using the general form of Archie's equation F = aø-m, where F is the formation factor, ø is the porosity, and a and m are constants that depend on characteristics of the rock. It was found that a and m varied significantly between sands, as did the exponent in the Archie relation I = Sw-n, where I is the resistivity index and S, is the water saturation. The average exponent, n, determined from all data was 50 percent greater at residual oil saturation than at residual water saturation. Samples from each sand exhibited differences in directional resistivity and/or permeability. The Bradford Third sand data showed correlation between resistivity and permeability anisotropy.

Jan 1, 1971

By Edward D. Thimons

The Bureau of Mines developed a stopping design that allows the stopping to be blown down by strong blast forces without incurring any permanent damage. Trials with the new stopping, dubbed the quick-fix blowout stopping, have been conducted in the Bureau's Safety Research Coal Mine at Bruceton, Pa., and in two New Mexico uranium mines. Results have been favorable in all cases. Compared with conventional brattice stoppings or wood bulkheads, the quick-fix blowout stopping is easier and less time consuming to install, is easier to maintain, and in most cases is just as efficient an air barrier. There is same indication that the shape of the stopping makes it more resistant to blast fore s than the fabric stoppings now in use.

Jan 1, 1976

By I. O. Salyer

This research was conducted with the objective of suppressing the respirable dust in coal mines by foam application. A formulation was developed for making a water-based, high-expansion, and limited stability foam. A horizontal boring machine was used as a laboratory coal mining model for generating coal dust. A modified laboratory foam generator was built. Foam was applied directly to the point at which dust was being formed by the cutter of the boring machine working against a block of coal. Coal dust was sampled with an impinger and analyzed for the particle count and particle size distribution. Coal dust suppression test results on freshly generated dust have demonstrated very clearly that in laboratory scale experiments over 90% of the respirable coal dust can be suppressed by foam. These tests were run when initial coal du t concentrations were 10 and 70 million particles per cubic foot (mppcf).

Jan 1, 1970

By J. P. Powell

Records show that systematic water flooding was begun as early as 1935 in Greenwood County and in 1937 in Butler County. Water flooding on some earlier projects in Greenwood County were described in a Bureau of Mines Report of Investigation.2/ This report presents a discussion of 4 projects -2 in Butler County, 1 in Greenwood County, and 1 in Butler and Greenwood Counties. The location of these projects is shown in figure 1. The projects have been in operation 6 to 12 years and have recovered about 6.6 million barrels of additional oil from the injection of 84.7 million barrels of water. Three of the projects take advantage of the elevation of the nearby hilly terrain, and water from the treating ponds flows by gravity through the filters into the clear-water tanks. By utilizing gravity flow, fewer pumps and less electrical energy is required, resulting in more economical operation.

Jan 1, 1956

By H. Tomlinson

"PURPOSE OF REPORTFatalities from falls of roof and coal are responsible for the death of more than 1,000 miners annually in the bituminous coal mines of the United States or practically one—half of the total fatalities in and about these mines. The men are killed by falls singly or in small groups and little or no publicity is given these accidents as they lack the spectacular features of gas and dust explosions. As a result, the public and even the miners have the impression that accidents from falls of roof and coal are just one of the unavoidable hazards of the coal—mining industry. This belief is not true. Accidents caused by falls can be avoided largely by the application of sound engineering principles, by education, and by proper leadership in the industry, just as gas and dust explosions and accidents caused by explosives have been reduced in recent years.The necessity for studying falls of roof and coal becomes apparent by referring to the following data from a table by Adams and Chenoweth:3"

Jan 1, 1933

By John P. Coughlin

The Bureau of fines has tested a portable microseismic processor recorder at the Galena Mine, Wallace, ID, both in an environmentally controlled enclosure and, with minimal protection, in a working area of the mine. In both trials the device demonstrated effective and reliable data acquisition capabilities.

Jan 1, 1985