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By Guy A. Johnson

This Bureau of Mines report summarizes the results of efforts to develop reasonably priced, reliable mine shaft fire and smoke protection hardware for metal and nonmetal mines. The hardware was incorporated into a viable prototype system that would minimize fire and smoke hazards. The design of the system had to be sufficiently flexible to be utilized in a wide variety of metal and nonmetal mine shaft and shaft station configurations. As a result of long-term, rugged field tests, an improved (second generation) system was developed. The hardware is now commercially available.

Jan 1, 1978

By Thomas C. Miller, Charles E. Mongan

"This publication is a progress report on Bureau of Mines studies in applying sonar techniques to roof-control problems in coal mines. Preliminary tests in the laboratory were made on layers of roof rock. To apply the experience thus obtained, a unit was designed and constructed and was used underground.The term ""sonar technique"" refers to the system of generating a beam of sound waves, shaping and directing the beam, introducing the beam into a medium to be studied, and examining any returning waves with a view of inferring the nature of the material traversed by the waves and the presence of interfaces or obstacles in the medium.The theory and actual underground experiments indicate that the sonic method is feasible. Information from physical tests made in the Bureau's Experimental mine confirmed the validity and potential usefulness of the sonar method. Lighter and more compact apparatus is desirable, and permissible equipment suitable for use in gassy or dusty mines must be developed. However, no particular difficulties are anticipated; consequently, this scientific approach to the exploration of roof strata shows definite promise. INTRODUCTIONThe problem of roof control in the coal-mining industry is of major importance. More than 50 percent of all coal-mine fatalities and 25 percent of all nonfatal serious injuries are caused by falls of roof, face, or ribs. The Bureau estimates that more than $128 million was spent by the coal-mining industry in 1958 for supporting roof."

Feb 1, 1960

Develop a method for recovering phosphate from a wide variety of complex western phosphate materials, including low-grade ores, tailings, and unused fines. Approach A flotation technique is used for this broad type of extraction. The method includes depression of phosphate minerals and anionic flotation of carbonate minerals, followed by cationic flotation of silicate minerals. How It Works A slurry is prepared for flotation by sizing to remove a low-grade, high-impurity slime fraction. Depending on the material, further sizing and/or grinding steps may be used to produce a size concentrate or to remove gangue. The flotation feed is conditioned with H2SiF6 and a fatty acid emulsion. The H2SiF6 is absorbed chemically to the phosphate mineral surface, making it strongly attracted to water and preventing adsorption of the fatty acid. Under these conditions, the fatty acid is a selective collector for carbonate minerals, which are removed as a froth product. Next, the silicates are floated with an amine reagent added directly to the slurry without additional pulp preparation.

Jan 1, 1982

Determine the effectiveness of remining operations in reducing contaminant load (acidity, iron, and sulfate) of discharges emanating from abandoned surface and underground coal mines. Background Until the implementation of remining initiatives, most States had regulations that held the operator remining an abandoned site responsible for preexisting acid mine drainage (AMD) discharges. For example, if a mining. company wanted to remine an area hydrologically connected to an existing AMD discharge, the company became responsible, as soon as the site was activated, for treating that discharge to meet effluent standards. If the mining operation improved the quality of the discharge, but the discharge failed to meet effluent standards, the company was held accountable for perpetual treatment. Because of this regulation, most mine operators avoided abandoned sites with minable coal reserves and AMD discharges. However, changes in remining legislation allow coal companies to be released from treatment liability as long as the post-remining pollution load does not exceed the pre-remining level. If remining can improve water quality through improved mining and abatement techniques, abandoned mine land (AML) areas that previously were liabilities could become

Jan 1, 1994

By J. H. Russell

As part of its efforts to maximize resource recovery, the Bureau of Mines conducted studies to recover valuable byproducts from Western phosphate beneficiation tailings. Potential byproducts include phosphorus, vanadium, and uranium. The objective was to determine roasting and leaching conditions for maximum dissolution of vanadium from tailings containing approximately 13 pct P205 and 0.23 pct V. Sulfuric acid leaching tests were conducted with the tailings either as a dilute suspension dried, or in a roasted condition with or without NaCl added during roasting. More than 90 pct of the vanadium was dissolved by roasting at 850° C for 120 min with 8-pct NaCl and leaching at 75°C for 120 min with an excess of 2N H2S04, By roasting without NaCl and avoiding the difficulties of the chloride impurity, nearly 80-pct vanadium dissolution was achieved with an 800° C roast for 180 min. Quadratic regression equations were derived to relate vanadium dissolution to roasting and leaching conditions.

Jan 1, 1982

By F. A. Rutledge

The Rainy Creek deposits lie at the western base of the Kilbuck Mountains, about So miles southeast of Bethel, in southwestern Alaska. The deposits were brought to the attention of the Bureau of Mines by placer miners on Rainy Creek after cinnabar concentrates were recovered by their gold-mining operations. In August 1947 the Bureau excavated 1,500 feet of dozer trenches totaling 2,547 cubic yards. Further hand trenching in the bottoms of the dozer trenches on the surface totaled 1,440 linear feet, or 40 cubic yards. Nineteen samples were taken for analyses.

Jan 1, 1948

By J. M. Singer

Approximate equations were used to compute the radiant heating of float coal dust by approaching flames for various combinations of particle size, dust path length (flame travel distance), flame temperature, dust concentration, flame speed, and flame length. The computed values of degree of radiant heating and flame travel distance for preheating the coal dust should be useful for estimating the increased fire hazard of different coal dust-flame parameters. Some findings relating to coal mine disaster control are-- 1. Coal dust clouds cannot be preheated to ignition temperatures by flame radiation alone when deflagration speeds are greater than about 10 m/sec. Thus it appears unlikely that radiation alone will cause flames propagating in dust clouds to accelerate to detonation velocities. 2. Small particles in the radiation flame zone caused by burnout and soot formation increase the degree of preheat significantly. 3. The concentration of float coal dust (radii = 3 to 40 microns) for maximum radiant heating usually peaks in the range 50 to 200 mg/liter of air.

Jan 1, 1970

By P. W. Jerant

The methane emissions from an advancing coal mine section were continuously monitored for 120 days. During this time, the section advanced 2,000 feet into virgin Pittsburgh coalbed producing 54,565 tons of coal with a total methane emission of 91 million ft3. Analysis of the data gathered showed that daily methane emissions did not correlate with overburden thickness and daily coal production. A good correlation was found between the daily methane emission and the average length of rib exposed to virgin coal.

Jan 1, 1976

By B. T. Brady

Laboratory measurements by the Bureau of Mines indicate that failure in dry rock specimens measuring approximately 13 cm in length is preceded by tilt anomalies lasting a few milliseconds. The tilt behavior is qualitatively similar to that reported to precede earthquakes. Test results suggest that the time duration of this tilt anomaly for laboratory specimens of this length is independent of rock type, in agreement with theoretical predictions and other experimental data on rock failures including earthquakes.

Jan 1, 1975

The Bureau of Mines has developed test procedures and criteria for evaluating explosive reactivity of explosive-contaminated solid waste substances generated by U.S. Army ammunition plants. These substances are produced as explosive-contaminated sludge from wastewater treatment plants, residues from the burning of munitions and explosives on open ground, and residues from deactivation furnaces. The characterization of explosive reactivity is a prerequisite for disposal of such waste materials, which may be contaminated with primary explosives, propellants, or pyrotechnic materials. The Bureau has proposed two tests for this purpose. These tests were developed to evaluate the explosive reactivity as defined in Title 40, Code of Federal Regulations (CFR), part 261.23(a)(6) and (7). These are the Bureau's gap and internal ignition tests, which determine the sensitivity to shock and thermal stimuli, respectively. This report also includes gap and internal ignition reference data for typical blasting agents, high explosives, propellants, and marginally reactive substances. These reference data were used to establish test criteria. The Bureau has evaluated over 400 samples of contaminated soil, sludge, and burning residues using these two test methods.

Jan 1, 1988

By Jack C. White

The purpose of this Bureau of Mines work was to develop information useful in improving copper recovery during copper milling operations. Eleven copper mill tailings from the Western United States were subjected to froth flotation and cyanide leaching to provide an experimental basis for comparing their beneficiation response. Recoveries in flotation concentrates made from mill tailings ranged from 65 to 15 percent, at copper grades of 13 and 2.2 percent, respectively. Liberated copper sulfide minerals present in two samples were readily recovered by laboratory froth flotation. Nine of the samples were less amenable to froth flotation because of physical locking between copper sulfide minerals and gangue. Correlations among tailings indicated that recovery of sulfide copper by flotation was directly related to the sulfide copper content. Empirical equations derived from flotation data provided average values for unrecoverable copper and for recovery efficiency. Flotation response of copper mill tailings may be predicted from the equations. Data from cyanide leaching provides an equation describing the limiting high values for removal of copper by this method.

Jan 1, 1974

By W. E. Wallace, V. Castranova, P. Hathaway, F. H. Y. Green, E. D. Recad, V. Vallyathan, M. J. Keane

Inhaled particle contact with pulmonary surfactant in the hypophase lining pulmonary alveoli was modeled in vitro by exposing two respirable sized dusts, kaolin and silica quartz, to lecithin, a major component of pulmonary surfactant, emulsified in physiologic saline. Lecithin adsorbs to the dusts upon incubation at 37º C and suppresses their cytotoxicity as measured by pulmonary macrophage and erythrocyte assays, suggesting that pulmonary surfactant provides a defense system against prompt cell membrane lysis by inhaled dusts. Subsequent pulmonary macrophage phagocytosis and lysosomal enzyme digestion of the coated dusts was modeled in vitro by incubation with phospholipase A2 for one hour. With increasing lipase activity, silica hemolytic potential was restored to native silica levels. Kaolin was retoxified to levels far in excess of native kaolin hemolytic potential. Elution, thin layer chromatography and phosphate assay of treated dusts indicate most lecithin on silica is digested to lysolecithin and desorbed, silica retoxification being due to surface and adherent lysolecithin effects. Most lecithin on kaolin is not digested in this same time; that which is results in adherent lysolecithin which is responsible for the kaolin retoxification. Digestion with phospholipases A2 and C together produces only weakly retoxified kaolin. Results suggest that surface adsorption properties which control the adherence of prophylactic surfactant distinguish the pathogenic potentials of quartz, kaolin and mixed dust.

Jun 1, 1988

By E. G. King

The work described in this Bureau of Mines report was undertaken to fill a need of industry for high-temperature heat-content data for uranium tetrafluoride. Without such data, heat balance evaluations of processes involving this substance are seriously hampered. Measurements of the heat content of uranium tetrafluoride were conducted at temperatures from 298° to 1,350° K. The melting point and heat of fusion were determined. The results are presented in suitable tabular form, and representative heat-content equations are included.

Jan 1, 1961

By Harry G. Dosh

Sillimanite, kyanite, and andalusite are aluminum silicates having the same chemical composition (Al2SiO5) and are used in the ceramics industry for the manufacture of high-grade refractories. Natural sillimanite with added corundum or other alumina to just short of mullite (3Al2O3 -2SiO2) proportions is unequalled for jobs wherein strength at high temperatures, resistance to spalling, and resistance to slagging by acid slags are desired. High-grade porcelain ware also requires these minerals. At the same cost, sillimanite would be preferred for most uses, but the lack of any large source of sillimanite bas given economic preference to kyanite or andalusite for special refractories and high-grade porcelain wares. Sillimanite-bearing schists were observed in Spartanburg County, S. C.; as early as 1937 by D. Hoye Eargle, geologist with the U. S. Soil Conservation Service. The mineral was not identified until 1942, when Miss Jewell Glass, of the U. S. Geological Survey, examined several of the deposits. This identification was confirmed in 1943 by Dr. Laurence L. Smith, of the University of South Carolina, when he examined the Spartanburg County deposits and found numerous additional occurrences of sillimanite schist in Greenville County. Subsequent work by the Bureau of Mines and the South Carolina Geological Survey has been responsible for the location of additional sillimanite-rich schist deposits in Spartanburg County. Between October 1, 1948, and November 21, 1948, the Bureau of Mines conducted an exploratory diamond-drilling project on the John Gideon property in the southeastern section of Spartanburg County (fig. 1) and drilled a total of 681.7 feet in six holes. Drilling indicated that the deposit is relatively shallow, as no ore was cut below the zone of weathering.

Jan 1, 1950

By John R. Shattuck

Preliminary examination of the McCormick chromite property was made by the Federal Geological Survey and the Bureau of Mines during the spring and summer of 1943. In October 1943 an exploratory project was undertaken by the Bureau in cooperation with the Survey and was completed in February 1944.The urgent need during the war for high-grade lump chromite such as produced at the McCormick mine, was one of the pertinent reasons for the project. The McCormick mine is situated about 12 miles southwest of the town of Sonora, in the foothill belt of the Sierra Nevada Mountains, Tuolumne County, Calif. The chromite occurs as irregularly shaped lenses in masses of dunite contained in a steeply dipping, sheared, serpentinized zone of peridotite, near a contact with granodiorite.

Jan 1, 1949

By Ludwig Schmidt

[The use of vapor-tight tanks has proved so effective in reducing the evaporation losses of petroleum that today practically all operators are using this typo of equipment. It has boon shown, however, that vapor-tight tanks should be supplemented with additional measures which will further reduce evaporation. Probably the most effective use of the supplemental measures are found on the small producing leases where the breathing losses from vapor-tight stock tanks materially affect the volume and gravity of the stored oil. The breathing loss from a vapor-tight stock tank that is filled and emptied daily is a negligible quantity. Also, the filling loss, which on the average varies between 0.1 and 0.2 per cent, usually is not of a sufficient quantity to affect materially the value of the crude. However, the combined breathing and filling losses from a vapor-tight tank requiring several days to fill are of sufficient importance to warrant the use of measures in addition to the vapor-tight tanks. The breathing losses are caused by atmospheric variations. Probably the greatest are the changes in atmospheric temperature which cause changes in temperature of the vapors in the tank. During the day, as the temperature increases, the gasoline-saturated vapors in the tank expand and are forced out into the atmosphere. At night the vapors are cooled and contract, drawing into the tank fresh air, which becomes saturated with gasoline vapor and is forced out of the tank during the following day. In Addition to the maximum and minimums temperature variations there are many smaller variations throughout a twenty-four period caused by showers, clouds, winds, and other atmospheric conditions which likewise cause the tank to breathe. The two mist common measures used by lease operators for reducing breathing losses in vapor-tight tanks are, first, operating; lease tanks under pressure, and second, the use of light colored paints anti tank houses. In this report these two methods are discussed together with their adaptability to lease operation. Results of experimental observations are given which show the reduction of evaporation looses where these supplemental measures have been used.]

Jan 1, 1927

By G. K. Derby

The Bureau of Mines studied the problems caused by airborne contaminants from welding exhaust in surface mining operations and investigated equipment designed to reduce existing hazards. Four commercially available welding-fume exhaust units were tested to determine their effectiveness. Results indicated that the four units had the capability of controlling airborne particulate concentrations and bringing them to within allowable exposure limits.

Jan 1, 1981

By Ralph L. Brown

The chemical properties of the unsaturated members of the aliphatic series of hydrocarbons are such as to render them " made to order" starting points or basic . materials for the synthesis of hundreds of important organic chemicals . The tremendous quantities of these unsaturated compounds that are being produced daily in the various coal carbonization and oil refining processes , and which at present have little value other than that of fuel , render a survey of the identity and ex- tent of occurrence of these compounds important from the viewpoint of economic utilization and resource conservation The increased need of liquid fuel and the relatively early exhaustion of petroleum resources will eventually require every utilization of liquid fuel products obtainable directly or indirectly from coal . Accordingly , the Bureau of Mines took advantage of an opportunity for examining the gaseous unsaturated hydrocarbons found in the gas obtained when a mixture of water- Collection of the material gas tar and coal is distilled in a gas-making retort . for examination was made possible through the courtesy of the Trent Process Corporation , Washington , D.C. , which was at that time carrying on at the Georgetown Gas Works , distillation of " amal gams " prepared from various coals and oils by the Trent process for cleaning coals . Kanawha gas coal ( 70%) and water gas tar ( 30 % ) from the Washington Gas Light plant were used in the " amal gam" being distilled at that time . The results obtained in this examination are presented here .

Feb 2, 1922

By G. L. Oldright, Virgil Miller

"INTRODUCTION The first ten papers of the series on smelting in the lead blast furnace described the operation at the custom smelter of the International Smelting Co., Tooele, Utah, and at the plant of the Bunker Hill Smelting Co., Kellogg, Idaho, which handled a very rich lead concentrate. These previous papers may be considered a picture of the traditional lead smelter treating custom ores and of the smelter that will treat the type of product likely to be made in the future - lead concentrates of an increasingly rich grade.The great plant at Trail is of special interest to those smelting lead products containing much zinc and faced with the necessity of transforming all of their byproducts into commodities which may be sold profitably. The plant is equipped to produce electrolytic zinc, lead, copper, silver, bismuth, and cadmium. Part of the sulphur evolved from treating the ores is converted into sulphuric acid. Complete fertilizers for agricultural purposes are also produced.The smelter of lead ores has long considered that zinc is one of the most difficult ingredients that he has to handle. Even with the gretat improvement in flotation practice today, the residues from electrolytic zinc plants leaching zinc concentrates must still be smelted for their lead content. Of the total gangue material not separated from the lead concentrate sent to the smelter, zinc is still one of the most notable in percentage. The most successful way of coordinating the over-all operations of a concentrator, an electrolytic zinc plant, and a smelter provided with a plant for re-treating the blast-furnace slag for its lead and zinc content must be of interest to many treating complex ores.ACKNOWLEDGMENTThe data in this paper were collected in cooperation with the Consolidated Mining & Smelting Co. of Canada, Limited, and its entire technical staff. Detailed acknowledgments of assistance received are given in the papers from which this one is briefed."

Sep 1, 1934

By Je M. Oh

The Bureau of Mines is conducting research to determine the high temperature oxidation resistance of substitute stainless steels (SS) containing two less strategic elements, Al and Si, instead of Cr. Chromium is considered to be a critical and strategic metal. Although the Cr content was reduced to 8 wt pct, the alloys showed better oxidation resistance than did 304 SS containing 18 wt pct Cr. Specifically, the alloys that contained Fe-8Cr-16Ni with combinations of Al and Si showed excellent oxidation resistance even at temperatures up to 1,000° C. In this study, the effects of the alloying elements on oxidation kinetics and morphology of oxides were investigated using a Cahn Rg electrobalance, scanning electron microscopy, an energy-dispersive X-ray analyzer, X-ray diffraction, and an electron microprobe. Aluminum and silicon additions in combinatin were more effective in providing oxidation resistance than either element was alone.

Jan 1, 1986