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By J. M. Goris

The U.S. Bureau of Mines, in a cooperative project with the University of Utah, Salt Lake City, UT, and Homestake Mining Co., Lead, SD, conducted in situ monitoring and numerical modeling of rock masses supported with cable bolts in two mechanized, cut-and-fill stopes and a shaft pillar at the Homestake Mine. Extensometers were used to measure rock displacement, while cable bolt strain gauges were installed to measure loads on both conventional and birdcage cable bolt supports. These instruments provided an assessment of rock mass behavior during mining as well as essential data for verifying results from computer analyses. The numerical modeling program FLAC was used to analyze cable bolt patterns and supports. Results from the evaluation study indicated that cable bolt strain gauges and extensometers were effective instruments for monitoring the behavior of rock masses supported with cable bolts. Also, numerical modeling of the 4S-48N stope using the FIAC code provided displacement values comparable with measurements from field extensometers.

Jan 1, 1993

By Joseph M. Singer

Having established that sodium chloride reduces the incendivity of explosives, the Bureau of Mines studied the effect of sodium nitrate in reducing ignition hazards. Gallery experiments showed that sodium nitrate reduced the incendivity of certain explosives to 8 percent natural gas in air but increased their incendivity to coal dust predispersed in air. Laboratory experiments using hot jets from explosions of stoichiometric mixtures of methane-oxygen-nitrogen showed that both sodium chloride and sodium nitrate reduced the incendivity to methane, to mixtures of coal dust and methane) and to coal dust. The difference between the gallery and laboratory results with respect to coal dust is attributed to temperature-time effects.

Jan 1, 1967

By V. R. Miller

The Bureau of Mines conducted research on substitute brazing filler alloys with properties similar to those of silver filler alloys in an effort to conserve silver and reduce hazards from cadmium emissions. Experimental work was conducted first on the commercial silver brazing alloys BAg-I, BAg-la, BAg-2, and BAg-3 to establish criteria for evalu-ating the substitute alloys. Properties investigated included the wettability of copper, brass, and steel substrates, and the strength of joints made with the filler alloys. A series of experimental alloys containing 50 to 60 pct Cu, 20 to 28 pct Mn, and 17 to 30 pct Zn was prepared and evaluated, together with Cu-Mn-Zn alloys with 5 pct Pb or 2 pct Ni. Wetting properties and joint strengths were not as good as those for silver filler alloys, and the high application temperatures reduced the copper and brass base metal strengths. However, experimental alloys containing 70 pct Cu, 15 to 20 pct Mn, and 10 to 16 pct Sn had wetting and strength properties approaching those of the silver filler alloys. The application temperatures for these alloys were high-er than those for silver fillers, but not as high as those for the Cu-Mn-Zn alloys. With the Cu-Mn-Sn alloy fillers, copper alloy joint members are less deteriorated by recrystallization than when applying Cu-Mn-Zn alloys. The Cu-Mn-Sn system has potential for further devel-opment as a substitute brazing alloy system, particularly if the melting temperature can be reduced by the addition of other elements without decreasing the ductility and wetting.

Jan 1, 1983

By Travis Q. Lyday

Australia was one of the world's principal producers of minerals and metals, and its minerals industry was a leading catalyst in promoting growth of the country. Australia was the world's largest producer of alumina, bauxite, diamond, ilmenite, monazite, opal, rutile, sapphire, and zircon. It was the premier exporter of alumina, coal, ilmenite, refined lead, monazite, rutile, and zircon, and was the second leading exporter of iron ore, after Brazil. Ranking behind China, the United States, the U.S.S.R., the German Democratic Republic, Poland, and the Federal Re-public of Germany, Australia was the seventh largest producer of coal (all grades) in the world. Australia was the fourth largest gold producer in 1988, after the Republic of South Africa, the Soviet Union, and the United States. It was the second largest producer of zinc, the third largest producer of nickel, the fourth largest producer of uranium, and the seventh largest producer of copper. 2 The country's mineral wealth was so extraordinary that it was virtually self-sufficient in most mineral commodities. Endowed with abundant resources of coal, natural gas, liquefied petroleum gas, and uranium, Australia was one of the few market economy countries that was a net exporter of mineral fuels. About 90% of Australia's consumption of crude oil was supplied by domestic production; this was expected to decline significantly about 1990, unless significant new oilfields were discovered.

Jan 1, 1990

By Robert H. Peters

Groundfall accidents have been the leading cause of fatalities in the underground coal mining industry for many years. Statistics from the Mine Safety and Health Administration (MSHA) indicate that approximately half of the victims of these fatal accidents were in an area where no devices had been installed to support the mine roof. This report was prepared by the U.S. Bureau of Mines to provide guidance to operators of underground mines concerning the use of techniques that may help to keep miners from going under unsupported mine roof. The report is divided into two major sections. The first section reviews the findings from several areas of empirical research pertaining to strategies for convincing employees to avoid unsafe acts and/or adopt self-protective behaviors. The strategies are (1) incentives and feedback, (2) disciplinary actions, (3) training (primarily fear communications and behavioral modeling), and (4) nondirective techniques. This literature review has a broad focus and should be helpful in making decisions about how to encourage a wide variety of types of self-protective behaviors. The second major section of the report presents an analysis of each strategy's potential for keeping miners away from unsupported roof.

Jan 1, 1991

By Kevin Malone

Chrysotile asbestos occurs in many counties in California, and a small production had been reported at times, but development of deposits had been disappointing. A reconnaissance survey by the Bureau of Mines indicated that several deposits in the serpentine belt in Shasta, Trinity, and Siskiyou Counties might contain enough asbestos of filler grade to supply the growing demand on the west coast. Accordingly from 1956 to 1958 parts of the Mount Eddy and Shasta View deposits were investigated by trenching and diamond drilling to determine their potential. The work comprised construction of roads, bulldozer trenching, excavation of areas for diamond drilling, sampling, and upping. The trenches were excavated to expose the surface extent of some of the asbestos-bearing areas, To determine the downward continuation of asbestos-bearing sections and to secure samples for test purposes, six diamond drill holes, totaling 1,738 linear feet, were drilled in two selected areas. The trenching and core-drilling indicated that the asbestos-bearing material occurs as ribs and lenses of varying thicknesses in a broad belt of serpentine, about 600 feet wide and several miles long,

Jan 1, 1962

By Ralph V. Higgins

The present methods of appraising the long-range performance of oil reservoirs are based upon physical properties of the crude oil and the permeability of the reservoir rock. By means of these methods the performance of a reservoir may be estimated throughout its entire life. Before these methods were used, the future performance was estimated mostly by extrapolating pressure-decline curves -a method that is satisfactory for extrapolating only for a short period into the future. One factor that affects satisfactory long-range prediction of reservoir performance is the extent to which small changes in the physical properties of the oil and differences in the choices of relative permeability influence the calculated oil recovery. Selection of the physical properties of the samples to represent those of the oil and rock for the entire reservoir is difficult. This report is concerned with the error in calculated recoveries that may result from these inherent difficulties.

Jan 1, 1956

By Gerald W. Elger

The Federal Bureau of Mines developed a modification in the conventional Kroll process for preparing high - purity hafnium metal . This modification involved the partial replacement of magnesium by sodium in the batch reduction of purified hafnium tetrachloride to sponge metal . The raw tetrachloride was purified either by thermal degassing of the volatile contaminants to the atmosphere or by fused- salt treatment . In the fused- salt treatment , the tetrachloride was contacted with molten alkali chlorides to remove the impurities . The reaction byproducts were removed from the metal by heat treatment in an evacuated furnace . The metal sponge was consolidated by melting into buttons or ingots , which were analyzed for impurities . The purity of the metal prepared by the modified process is superior to that of the metal produced by the conventional method . The hafnium metal was comparable to crystal - bar hafnium except for the oxygen content , despite the abnormally high impurity concentrations in the raw tetrachloride . Several ingots were successfully cold - rolled to sheet .

Jul 1, 1960

By D. Bienstock, J. H. Field, M. J. Lempel

A computer program is presented to perform the detailed and numerous calculations required for determining the interface temperatures and steady - state heat flow through a furnace wall composed of several refractories in layers . A method is developed that will allow the designer to determine the various thicknesses for each refractory layer to minimize either the total wall thickness or the cost of the wall per unit of area . A sample problem is presented and analyzed to illustrate the techniques involved .

Jan 1, 1964

By Daniel Harrington

On the night of June 8, 1917, the flame of a carbide lamp accidentally set fire to the uncovered and frayed insulation of an armored power cable near the 2,400-foot level of the North Butte Mining CO.'s Granite Mountain shaft. How this, insulation accidentally became exposed is explained on page 15. The highly flammable oiled fabric set fire to the shaft timbers, and as this is a downcast shaft the fire spread with great rapidity, soon filling the mine workings with smoke and gas. At the time 410 men were working underground, 247 of whom escaped by various means, but most of the 163 remaining were probably overcome soon after the fire started, and perished. Only two men were actually burned. The cause of the disaster was purely accidental. The immediate effect was the unexpected reversal of normal conditions; the ultimate effect was great loss of life and the destruction of the main hoisting shaft, putting it temporarily out of service. The work of rescue and fire fighting continued eight days. The following pages present an attempt to draw some practical conclusions and suggestions from this disaster. The property of the North Butte Mining Co. consists of about 220 acres in the northeastern part of the Butte district, Montana. Next to the Anaconda Copper Mining Co. it is the largest producer of the district. In 1916, the year before the disaster, there were 1,160 men employed. The output was 560,947 tons of ore, which yielded 24,498,181 pounds of copper, 1,047,063 ounces of silver, 1,712 ounces of gold, and 412,953 pounds of zinc. The profit was $2,479,595. The total development work for that year was 21,694 feet. During the first half of 1917, the year of the accident, the daily tonnage of ore averaged 2,000, an increase of 400 tons over that of the year 1916.

Jan 1, 1922

By Graham W. Marks, Clyde A. Bridger

"INTRODUCTION An electrolytic process for the preparation of metallic cobalt has been developed recently in the Bureau of Mines Experimental Station at Boulder City, Nev. Chemical analysis shows this cobalt to contain impurities in small percentages, chief of which is nickel. It is desirable to be able to determine these impurities spectrographically. This report is concerned with a procedure for the spectrochemical determination of nickel in cobalt.Previous spectrographic work on cobalt was done by Breckpot and Mevis,/ who used the method of homologous pairs of lines. However, it was felt that a more detailed investigation was needed, employing the method of internal standards.ACKNOWLEDGMENTWe are indebted to B. G. Knickerbockor and his staff at the Boulder City, Nev., station of the Federal Bureau of Mines for their cooperation, and particularly to Richard W. Lewis and Robert G. Sanderson, who prepared nickel-free electrolytic cobalt for us."

Feb 1, 1948

By William D. Riley

In order to evaluate the corrosion resistance of zirconium in mineral extraction processes, such as a clay-hydrochloric acid leaching process for extracting alumina, the Bureau of Mines conducted corrosion studies in HCl-AlC13-FeC13 environments. A series of weight loss and electrochemical tests were conducted at 25° and 65° C in aluminum chloride (AlC13) plus hydrochloric acid (HCl) solutions containing 0 to 1,000 ppm ferric ion. It was determined that zirconium, which normally exists in a passive state in chloride-containing solutions, undergoes pitting attack in solutions containing more than 100 ppm of ferric ion. It is also shown that an oxide film prepared in air at high temperature offers protection in acid solutions containing levels of ferric ion from 300 to 1,000 ppm.

Jan 1, 1981

By H. O. McDonald

The Bureau of Mines reviewed the chemical vapor deposition (CVD) literature of the group IVB, VB, and VIR elements. This review was utilized in the Bureau's research to provide erosion-, abrasion-, and corrosion-resistant coatings for valve components used in coal gasification units. This report attempts to bring together the many CVD references that have been published since 1966. Each of the group IVB, VB, and VLB metal coatings were reviewed, and some of their preparation methods, uses, and properties are given. A total of 160 references were found for the nine elements. Isotope separation, stronger steels, solar absorbers, alloys, superconductors, optical fibers, and coatings to increase the life of materials are some of the new uses for CVD.

Jan 1, 1979

By Roy J. Greenfield

The overall purpose of this research was to improve the understanding of how the post disaster seismic location system works, what determines the signal size, what is the character of the seismic noise, how well the system can detect blows from a trapped miner, and how well the source of the blows can be located. Based on an improved understanding of the system, improvements were suggested in the seismic subarray configuration, and in the system deployment procedures. An important part of this research was to become familiar with the seismic system operation and to work with the Westinghouse Electric Corporation and MSHA personnel to modify and improve the system. To accomplish this we participated in the planning, execution, and data analysis for a number of seismic field tests. Several in-mine field tests were conducted. From these tests the capabilities of an in-mine seismic system were analyzed and specifications were made for designing an operational in-mine system. Several portions of the work done on this grant were covered in previous reports. In particular the capabilities or the presently operational surface based seismic location system has been thoroughly documented by Durkin and Greenfield (1981). Portions of the location procedures and effects of mine openings on seismic signals have also previously been published. These portions or the work will only be summarized in this final report.

Jan 1, 1982

By F. R. Cattoir

The Federal Bureau of Mines refined chromium from an aqueous electrolytic process in molten sodium chloride-chromium chloride electrolytes. Oxygen and nitrogen contents were reduced by a factor of 10 to 40, but most other impurities were little changed. The product usually contained a little more iron than the feed. Since iron was entering the bath from the iron pot and the graphite liner at a nearly constant rate, contamination of the chromium deposits by it was more serious at low currents and deposition rates. A few runs in an iron cell with a nickel liner yielded chromium containing one half as much iron as the feed, but up to 1.5 pct. nickel. In all cases the anode feed lay in the bottom of the container, which itself was used as the anode connection. With a 12-in. cell, variations in applied voltage from 0.05 to 1.5, in current from less than 10 to over 100 a., and in initial cathode current densities from less than 100 to over 2,000 a./sq.ft. had little or no effect upon the analysis of the metal produced) except for iron content. Changes in bath analysis from 3 to 11 pct. chromium were also without effect. These changes did bring about large differences in the physical forms of the crystals obtained. The thick heavy crystals produced at low voltage and current contained voids which made them difficult to leach free of chlorides. Easiest to leach were the thin leaf-like crystals obtained at around 1 v.

Jan 1, 1960

By Joseph Chalmers

Stimulative methods of production, whereby the total recovery of oil from natural reservoirs is increased, have come into considerable prominence during the past 15 years. In many oil-producing areas properties considered ready for abandonment by ordinary producing methods have responded to some form of stimulation, and their economic lives have been extended. The stimulative method having widest application is the injection of air or gas into the reservoir formations through selected input wells and is commonly referred to as the "gas drive." As a result of the many successful "gas-drive" operations operators are depending more and more upon this method for increasing the ultimate recovery of oil from their properties. A number of factors influence the efficacy of different gases as propulsive agents in recovering oil from sands. Gases of high density and viscosity show a tendency toward a slightly higher efficiency than those of lower density and viscosity. The solubility of the gas in the oil also affects the efficiency of oil recovery. Not only does dissolved gas decrease the viscosity of the oil, but dissolved gas that expands from solution in the oil tends to increase the effectiveness of a "gas drive." Interfacial tension between the oil and the gas and its effect upon the recovery of oil by gas injection are factors of which little is known. Dr. A. G. Loomis expressed the opinion that interfacial tension probably plays a minor role in the recovery of oil, except under conditions that produce a gas-oil foam. In connection with the above physical properties that influence the action of a pressure medium, control of the injected volume of the pressure medium is perhaps the major factor. The rate of gas injection determines to a great extent the amount of slippage and the resulting efficiency of the operation. The importance of volume control is realized when one considers that frequently it is the only factor that is under complete control of the operator.

Jan 1, 1930

By A. H. Beebe

This paper describing the operations of the Cresson mine of the Cresson Consolidated Gold Mining & Milling Co. at Cripple Creek, Colorado, is one of a series of papers on mining methods and costs being prepared by the United States Bureau of Mines. The Cresson has recently been the most, important mine in the Cripple Creed district. During 1932 and 1933 an average of 230 tons of new ore (excluding dump material) that averaged about $10 in gold was shipped daily; 150 to 175 men were employed. Stoping was by the shrinkage method exclusively. The ore was screened washed, and hand-sorted at the surface and shipped to the Golden Cycle mill at Colorado Springs for treatment. A considerable proportion of the production was made by lessees working under the so-called "split-check" system. The authors are indebted to the management of the Cresson Consolidated Gold Mining & Milling Co. for permission to publish this paper.

Jan 1, 1934

By James Paone

Land utilized by the mining industry from 1930 through 1971 amounted to 3.65 million acres, or 0.16 percent of the land mass in the United States. Land reclaimed during the same period was 1.46 million acres, or 40 percent of the land utilized. This report includes data on land use for wastes from underground and surface mining, for wastes from mill operations, and on subsidence. Data on land use and reclamation were obtained from operating companies, mining organizations, appropriate State agencies, and others concerned with such activities. The 10 leading States in land used for mining in 1971 were, in decreasing order, Kentucky, Pennsylvania, Arizona, Ohio, California, Florida, West Virginia, Illinois, Minnesota, and Indiana. Mineral commodities accounting for a major portion of land use are, in decreasing order, bituminous coal, sand and gravel, stone, copper, phosphate rock, iron ore, and clay; for coal, these commodities are produced principally by surface mining operations. Reclamation over the 42-year period was largely on lands utilized for surface mining of bituminous coal. New surface mining methods, particularly for coal, incorporate some form of land restoration.

Jan 1, 1974

By D. A. Stanley

The Bureau of Mines is investigating a method of dewatering flocculated fine-particle waste that involves treating the waste with a high molecular-weight polymer such as polyethylene oxide (PED) followed by dewatering on a static screen and/or in a trommel. Dilution of the polymer solution used for dewatering and use of the ion-exchanged form of the montmorillonite clay were found to be major factors determining the amount of polymer required to dewater clay-containing slurries. The amount of polymer, A, required to dewater ion-exchanged montmorillonite can be described by the equation, An = kC + b where n, k, and b are empirical constants and C is the concentration of the polymer solution used for dewatering. Clays that require large amounts of polymer for dewatering also dewater to a lower solids content. The concentration of the polymer solution is important because it affects the radius of the polymer coil in solution and hence its ease of transfer to a bridging configuration by shear. The constant, n, a function of the charge to hydrated radius of the exchange ion, relates to the strength of the bond between the polymer and the surface of the clay through a water bridge. The constant k is related to the hydrated radi-us for sodium or to the unhydrated radius for the other exchange ions.

Jan 1, 1986

By R. E. Siemens

The Bureau of Mines sought to correlate the variation of structure-sensitive superconducting properties with microstructure in selected Cb-Hf alloys and to compare the experimental results with those predicted by the GLAG theory. Alloys in wire and rod form were evaluated by critical temperature, critical current, magnetization, resistivity measurements, and optical and electron microscopy. In the absence of an external magnetic field, the current carrying capacity of columbium was greatly reduced with addition of up to 85 wt pct Hf, but a large increase in Ic occurred for Cb-90 wt pct Hf. Favorable Ic-H behavior was observed in cold-drawn alloys containing 25 and 57 wt pct Hf. Correspondingly, a maximum in Tc occurred at 10-25 and 90 wt pct Hf. Four- or five-hour heat treatment at 600° C resulted in maximum Ic values and maximum hysteresis in magnetization. Dislocation pileup, polygonization, and fine precipitates, responsible for flux pinning, are listed in order of their effectiveness as pinning sites. Sites having an average separation of 1,500 to 3,000 A and a diameter of 1,000 A or less were most effective in influencing Ic-H and M-H behavior. The resistive critical fields increased smoothly to a maximum of 80 k0e between 60 and 65 wt pct Hf. Highfield, mixed state, reversible paramagnetism was observed in some alloys; however, the GLAG theory was in good agreement with experimental results for the majority of the composition range studied.

Jan 1, 1969