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By J. Schlocker

The present emergency has greatly stimulated interest in the light metals - aluminum and magnesium - owing to their extensive use in airplane construction. The $63,000,000 plant being erected in the Las Vegas Valley by Basic Magnesium, Inc., under the auspices of the Defense Plant Corporation,

Jan 1, 1942

By Henry E. Blake

The purpose of this Bureau of Mines investigation was twofold. The first phase of the work was to determine the technical and mechanical feasibility of defluorinating low-grade siliceous fluorspars on an intermediate scale by high-temperature pyrohydrolysis in a rotary kiln. The second phase was to react the liberated hydrogen fluoride (HF) offgas with alumina monohydrate to produce commercial-grade aluminum fluoride (85 percent AIF3). The two phases of the work were to be integrated into a single continuous process. Evaluation of the data shows that low-grade siliceous fluorspars can be successfully defluorinated, either in a solid or a molten state, in a gas-fired rotary kiln in the presence of water vapor at 1,250° to 1,350° C. The water produced by combustion of propane was sufficient to yield defluorinatians of 75 to 85 percent.

Jan 1, 1962

By W. A. Cole

The sulfur shortage that existed during the Korean conflict stimulated interest in coal measures as possible sources of sulfur. One of the areas brought to the attention of the Bureau of Mines was in Marion County, Iowa, where comparatively high-sulfur coals and other marcasite-bearing strata were known to occur. A Bureau of Mines engineer inspected the marcasite occurrence on December 4, 1954; this prompted further work on the Iowa coals and associated formations as a source of iron sulfides. An investigation of the Iowa high-sulfur coals was undertaken including core drilling, field reconnaissance, and compilation of data pertinent to consideration of the following: 1. Upgrading Iowa coal by mechanical cleaning and the feasibility of recovering sulfur from coal brasses. 2. Possibility of processing the high-sulfur coals by adaptation of methods employed in processing industrial gases to produce sulfur and sulfur products. 3. Possibility of finding concentrations of iron sulfides in associated rock formations in sufficient quantity for economical recovery.

Jan 1, 1957

By C. W. Smith

Research was conducted by the Bureau of Mines to determine the effectiveness of various types of crushers for use with the Bureau-developed pneumatic concentration technique for mica. Three types of crushers were investigated in this study, a roll crusher, a jaw crusher, and a hammer mill. All the mica concentrates produced contained over 82 percent mica, but recoveries varied considerably. The roll crusher gave the lowest recovery of 46 percent of the mica followed by the jaw crusher with a recovery of 50 percent of the mica. The hammer mill proved the most effective, producing four concentrates with recoveries of at least 70 percent.

Jan 1, 1981

By E. R. Cole

Bench-scale research at the Bureau of Mines has resulted in the successful development of a combination electrorefining-electrowinning method for recycling all the lead in scrap batteries. The method reduces energy consumption and eliminates toxic emissions, in contrast to present pyrometallurgical smelting, and the lead produced is pure enough for use in maintenance-free batteries. Anodes cast from molten lead scrap were electrorefined in 1-and 2-liter plastic cells using an electrolyte composition of 70 g/l Pb and 90 g/l free H2SiF6 (fluosilicic acid). Both reagent-grade and waste H2SiF6 were used. Cathode starting sheets were made from refined lead. Aloes, and later bone gelatin, and calcium lignin sulfonate addition agents were employed. The sludge remaining after separation of the lead metal was treated in a two-step leaching operation to solubilize the lead for recovery by electrowinning. Conditions for electrowinning were essentially the same as for electro-refining, except that insoluble Pb02-Ti (lead dioxide-coated titanium) anodes were used. The best results for both electrorefining and electrowinning were obtained with a current density of 170 amp/m2 and a cell temperature of 25° to 35° C. Cathode purity ranged from about 99.9 to 99.99+ pct Pb. Maximum energy consumption after 3 days, for electrorefining and electrowinning, was 90 and 700 kwhr per metric ton of refined lead, respectively.

Jan 1, 1981

By B. D. Hanson

The U.S. Bureau of Mines has developed an interactive computer program which enables the user to identify the effect of cutting system changes on relative dust generation and forces for continuous miner drums. The program simultaneously evaluates machine and coal seam parameters, and those parameters which the user can control. One or more of these parameters may be changed to determine their individual or collective effect on relative dust generation and cutting forces. The program is written in the BASIC programming language. A complete program listing is included along with user instructions and sample outputs.

Jan 1, 1989

By K. K. Kelley

"In an earlier consideration of the vapor pressure of iron 3/ it was found necessary to estimate the specific heat of gaseous iron to write satisfactory free-energy-of-vaporization equations for the several forms of iron. That the specific heat of gaseous iron will exceed greatly the classical value of Cp = 4.967 calories per gram-mole per degree is evident from even a cursory Lamination of its spectrum. The two lowest energy states are separated by only 416 cm-1, which is small enough so that the second state is effective, theoretically, at below room temperature. Such phenomena are by no means uncommon, but, while they have been recognized with substances that ordinarily are encountered as gases, classical gaseous specific--heat values still are used, often without question, for the vapors of metals and other elements that are solids under ordinary conditions. The following calculations for iron and copper gases are presented to illustrate the sort of deviations from classical values that are encountered with metal gases.The methods employed in calculating from spectroscopic data of thermodynamic quantities such as specific heat, entropy, and free energy have been described, in detail by Giauque 4/ and others. These will be briefly reviewed here. It is customary to separate the translational energy of a molecule from the rotational, vibrational, and electronic energies. In the case of monatomic gases, only translational and electronic Energies are involved. The classical expression for the specific heat of a mona¬tomic gas, Cp = 4.967, deals only with energy stored in the molecule as translational energy and consequently is valid only in temperature ranges in which no appreciable number of molecules undergoes a change in electronic state."

May 1, 1937

By C. M. McCulloch

As part of the Bureau of Mines methane control program, the Pittsburgh coalbed was studied in Washington and Green Counties, Pa., and in Marion and Monongalia Counties, W. Va., where this coalbed is now being mined at its greatest depth. The coalbed thickness appeared to be structurally controlled; the bed was generally thinner near the axes of anticlines and thicker near the axes of synclines. The overburden isopach shows a similar relationship. Most of the clay veins in coal occur in the synclinal troughs, generally under sandstone roof. Cleat orientations measured in 18 underground mines showed that face cleats are perpendicular to the axial trends of the folds, and the butt cleats are parallel to the axial trends, indicating structural control of the cleat. Measurement and analysis of surface joint orientations provide a method for predicting the cleat orientations of the coalbed, but linears measured from infrared photographs and photoindex sheets helped only to determine regional trends. The results of these investigations provide a geologic framework for rational planning for underground mine development to use the best available technology to cope with methane emissions, coalbed discontinuities, and related ground support problems.

Jan 1, 1975

By J. S. Browning

The physical properties and specific gravity ranges of various liquids and salt solutions used for laboratory sink-float separations of rocks or minerals are presented. The test equipment and techniques employed by the Bureau of Mines in making sink-and-float separations of particles as coarse as 3 inches to as fine as 400 mesh are described. Also discussed are methods of recovering and reclaiming the liquids or salts from the minerals and wash solutions, as well as the hazards encountered and precautions to be followed while working with the materials. The laboratory use of various liquids for separating minerals of different specific gravities has been recognized for many years. During this time, laboratory sink-float procedures have proven their utility as a rapid and moderately accurate means for determining the mineral content of ores, test products, and plant products in certain nonmetallic concentrating operations, such as those producing mica, spodumene, kyanite, and so forth. These procedures also have been used as analytical tools for determining the mineral content and associations of other metallic and nonmetallic ores.

Jan 1, 1961

By John Nagy

Data from experiments and literature on gas and dust explosions in closed vessels are presented to show the effects of the vessel size and shape; the initial pressure, temperature, and turbulence; and the fuel-air ratio and the strength of ignition source on pressure and rate of pressure rise. An attempt is made to correlate some of these parameters with an elementary mathematical model. Analyses of data on 17 vessels--spherical, cubical, cylindrical, and rectilinear in shape--ranging from 0,018 to 905 cubic feet in volume were made. Although the study was initiated to provide information primarily on dust-explosion phenomena, some data were obtained for gas explosions so that the factor of initial turbulence caused by the pneumatic blast used to disperse dust could be evaluated. The mathematical interpretation of the explosion phenomena was in general accord with the experimental data, and correlation was obtained for several factors affecting explosion development. Neither vessel size nor shape affected maximum pressure (when heat loss was neglected). The rate of pres-sure rise decreased as vessel size increased, and the rate was proportional to the ratio of the surface area of the vessel to its volume. Induced initial turbulence markedly increased the rate of pressure rise and slightly increased the maximum pressure. Changes in initial pressure produced proportional changes in maximum pressure and rate of pressure rise. Initial temperature and maximum pressure were inversely related, but initial temperature had little effect on the maximum rate of pressure rise. Comparative experiments showed no appreciable difference in explosion development of gas and dust fuels. The vessels and experimental work are described, and all data are given in tables. The mathematical model will facilitate extrapolation from laboratory to industrial conditions and will allow comparison of results obtained in different laboratories.

Jan 1, 1971

By H. L. Riley, B. W. Gandrud

"INTRODUCTION AND SUMMARYIn connection with a program of research work on coal at its Southern Experiment Station, the Bureau of Mines, in cooperation with the University of Alabama, conducts washability studies of samples of coal from coal fields in Alabama and other Southern States in which commercially important deposits of coal occur. The first such study on coal from a bed in the Arkansas field has been completed, and the results are presented in this report.One of the main objectives of a washability study is to obtain technically and commercially important data in connection with the best methods for preparing and utilizing the Nation's limited reserves of good coking coal. Such information is important from the standpoint of conservation in that it facilitates selection of preparation methods that will yield a good grade of coking coal with a minimum of losses of coal in the rejects.The coal on which this report is based was obtained by underground and tipple sampling at the quality mine of the Quality Excelsior Coal Co. about 3 miles east of Hackett, Ark. This mine operates in the Upper Hartshorne bed, which, as the main source of coal in what is known as the Hackett-Excelsior district, yields an excellent grade of low-volatile coking coal, which is marketed at steel plants in Colorado and California. Production from this bed by the major producers in the Hackett Excelsior district was at the rate of about 125,760 tons annually in 1949, according to the Keystone Coal Buyers Manual. 2/In the laboratory, the tipple sample was crushed to 6-inch top size and screened on a 2-inch round-hole screen. The 2-inch to 0 undersize, amounting to 71.4 percent of the total sample, was fractionated into a series of screen sizes and float-and-sink products to get data for determining the washability characteristics of the coal. Before the screening and float-and-sink tests were made, however, machine cuttings, which are now gobbed underground, were added to the 2-inch to 0 sample. Enough of these cuttings were added so that the resulting mixture was considered representative of what the 2-inch to 0 run-of-mine coal would be if all machine cuttings, including the part now being gobbed, were brought to the tipple as a part of the run-of-mine coal.The mixture obtained referred to in this report as the run-of-mine or raw coal."

Mar 1, 1953

By Stephen Utter

This report summarizes the procedure and results of an investigation to determine the stresses in the rock around an underground opening in the Climax molybdenum mine, Climax, Colo. This study is part of an overall investigation conducted by the Bureau of Mines to determine the stresses induced by block-caving mining. The purpose of this study is to obtain estimates of the magnitudes and directions of the principal stresses, the location of the maximum stress concentrations, and the effect of topography on the stresses.

Jan 1, 1962

By Fred Garcia, William P. Diamond

As part of its mine safety and health research program, the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, has been investigating the geologic and mining factors influencing methane gas emissions associated with longwall mining. A primary focus of this research has been the consequences of increasing longwall panel dimensions, particularly face width, in gassy coalbeds. Continuous longwall face emission monitoring studies were conducted at two adjacent mines operating in the Pocahontas No. 3 Coalbed, where longwall faces were to be extended from 229 to 305 m (750 to 1,000 ft). Average longwall pass methane emission rates for 229-m (750-ft) wide faces were 61 % (0.072 m31sec (153 cfm)) higher at the VP-3 Mine than at the VP-1 Mine. It was predicted by regression analysis of methane emissions data from 229-m (750-ft) wide faces that extending faces to 305 m (1,000 ft) would increase methane emission rates by only 7%, or 0.009 m3/sec (20 cfm), to 0.144 mysec (304 cfm) at the VP-1 Mine. In contrast, it was predicted that extending faces to 305 m (1,000 ft) at the VP-3 Mine would increase methane emissions by as much as 13%, or 0.029 mysec (65 cfm), to 0.268 dlsec (567 cfm).

Jan 10, 1999

By N. A. C. Smith

One of the most important considerations in any manufacturing industry is the production of stable material, that is, material which will not change in quality before it reaches the consumer. The manufacturer of gasoline, the refiner of crude petroleum, is handicapped in this respect by the varying nature of his raw material, but as far as it is commercially practicable, he has endeavored to improve his product, and in most cases he has been eminently successful. It sometimes happens, however, that a gasoline that is apparently normal when first made, will In time deposit small quantities of a gummy substance. The present Investigation was undertaken in the hope that it would throw some light on these gums and indicate how their formation might be prevented.

Jan 1, 1922

By Ruth F. Brinkley

This report is the 17th of a series originally issued annually, and more recently bienially, to acquaint the reader with the work of the Division of Explosives Technology, Federal Bureau of Mines. It differs from preceding reports in that its material is presented in two parts: Part I reviews briefly the overall activities of the Division during fiscal years 1955 and 1956;4/ part II presents in abstract form, the publications of the Division during that period. As it is not unusual for research completed in the course of one report period to be published only in the following period, the Bureau believes that the present approach will give a more accurate presentation of its work for the period considered. The Bureau hopes too, that the somewhat more concise presentation will prove convenient to the reader.5/ PART I -RESEARCH AND TECHNOLOGIC ACTIVITIES The activities of the Division during fiscal years 1955 and 1956 reflected the steadily growing preoccupation with factors affecting the safety of permissible explosives and those affecting the tests used for approval of these explosives. Findings by a team of French investigators prompted a study of the influence of atmospheric moisture on the ignition of firedamp by

Jan 1, 1961

By K. P. V. Lei

The Bureau of Mines as part of its research effort to minimize the generation of hydrometallurgical waste, investigated a sodium sulfide leaching-electrolysis procedure for treating hydrometallurgical residues for elemental sulfur and base-metals recovery. Research was conducted on a leaching residue from a lead concentrate. The following procedure was developed. 1. The elemental sulfur was dissolved as polysulfide with an Na2S solution. 2. The resultant metal sulfide bearing residue was oxidatively acid leached in a cationic membrane electrolysis cell; the metals were solu¬bilized at the anode, and a base was generated at the cathode. 3. The elemental sulfur was recovered from the polysulfide solution by neutralizing with the acid in the anolyte. Byproducts of the neutralization were H2S and a sodium salt solution. 4. Sodium sulfide was regenerated by reacting the H2S byproduct with the base in the catholyte. 5. Lead as PbCL2 was recovered from the anode residue by brine leaching, and the other metals were recovered from the sodium salt solution as metal sulfides. 6. The barren filtrate from the metal sulfide precipitation constituted the recycled electrolyte. Ninety-eight percent of the elemental sulfur, 98 pct of the lead, and up to 80 pct of other accessory metals were recovered from a residue obtained from the FeCl3-NaCl leaching of a lead concentrate.

Jan 1, 1982

By A. G. Starliper

Research was conducted by the Bureau of Mines to determine feasible roasting methods for the removal and the recovery of germanium, cadmium, and lead as enriched fractions from sphalerite concentrates. The two types of roasting processes studied were: (1) Batch, with a stationary bed, and (2) continuous, with a suspended bed, Results indicated that either method gave satisfactory metallurgical recoveries} but the continuous process is recommended because of inherent advantages. Final products were enriched fractions that could be treated by conventional methods for production of metallic germanium, cadmium, and lead. In the batch process, the concentrates were placed in a large tube furnace and heated at 1,080° C, an average of 3 hours. During the heating period, inert, reducing} or sulfur-laden gases were passed over the stationary charge to convey the sublimed metal sulfides from the hot portion of the tube to a lower temperature condensing zone at the end of the tube, where the metal sulfides were collected on baffles and recovered. In the batch and fluidizing roasting processes alike, the gases passed over or through the charge and served only as carriers for the sublimates and as suspension media in fluidization roasting. Since both processes depended on the volatilization, at relatively high vapor pressures, of the sulfides of germanium, cadmium, and lead, it was imperative that very little oxygen come in contact with the charge to alter the sulfide minerals. Germanium has a high affinity for oxygen, but in this instance it was buffered by being in solid solution in zinc sulfide.

Jan 1, 1961

Reduce face methane concentrations and help prevent miners from working under unsupported roof while moving the curtain. Approach Use water sprays on the continuous mining machine to move and direct air to the face, and also provide appropriate installation guidelines for the most effective use of the system. I n laboratory tests and under actual mining conditions, the spray fan has proved an effective means of ventilation. Recent observations in the field, however, have shown that not enough technical information is widely available on proper installation of the spray fan. This Technology News is designed to rectify that situation by providing a concise guide for spray fan installation. How the System Works Good ventilation is essential for methane control. The spray fan system repositions regular water sprays to help the normal exhaust face ventilation do a more effective job. The various water sprays help in many ways: 1. Side sprays bring clean air along the side of the miner into the off-curtain corner.

Jan 1, 1983

By Thomas R. Bur

Symmetry theory, based on ground work established in the study of single crystals and experimental procedures utilizing ultrasonic pulse velocities of spherical specimens plotted on equal area polar projections, enables the direct identification of a material's elastic symmetry system and the determination of its orientation, as well as the position of the elastic coordinate axes. The method is especially useful for elasticity studies of polycrystalline and amorphous materials for which this knowledge of symmetry is a prerequisite in determining the independent elastic constants. Projections based on theoretically derived velocities are given for a single crystal from each of the major crystallographic symmetry systems except the triclinic. Projections based on experimentally derived velocities are given for one brass and several rock spheres.

Jan 1, 1969

By Robert J. Timko

The objective of this Bureau of Mines research work was (1) to determine how well the E. I. Du Pont de Nemours and Company P-2500 personal dust sampling pump controls the flow rate at 2 L/min and (2) to compare respirable dust mea-surements made using the P-2500 with those made using a nonpulsating sampling flow system, both using the Dorr-Oliver 10-mm nylon cyclone dust size classifier. The calibrator and the operation manual for the P-2500, supplied by the manufacturer, were also evaluated. Flow tests consisted of long-term (6-to 8-hour) flow stability tests at various backpressures, a low-flow indicator examination, flow controller response time tests and pulsation tests. Dust tests were performed using coal, silica, and Arizona road dust. No tests were performed to examine effects of temperature, barometric pressure, vibration, or mechanical shock. These pumps performed well within manufacturer specifications in all tests.

Jan 1, 1982