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By Aldo L. Furno

Sufficient quantities of combustible vapors are released by some sulfurs to produce flammable atmospheres under prolonged storage. Hydrogen sulfide and carbon disulfide appear to be the principal flammable constituents in the vapor space above molten sulfur. If sufficient carbon disulfide is present, ignition of the vapor-air mixtures can occur spontaneously on contact with the heated surfaces found within storage tanks.

Jan 1, 1963

By M. J. Ferrante

The Bureau of Mines recovered rhenium powder from scrap tungsten alloy containing approximately 25 percent rhenium. Oxidation of the scrap at 950° C separated volatile rhenium heptoxide from tungsten trioxide. Minor amounts of tungsten, iron, and nickel were removed by selective precipitation from a rhenium solution from which was recovered crystalline ammonium perrhenate. Experimentation showed that hydrogen reduction of minus 325-mesh ammonium perrhenate at 1,000° C produced rhenium powder averaging 2.1 microns in size (Fisher Sub-Sieve method). The powder contained <50 ppm of total metallic impurities and 1,070 ppm of total interstitial impurities. Sintered compacts had a density of 95 percent of theoretical. Approximately 96 percent of the rhenium contained in the scrap alloy was recovered.

Jan 1, 1969

By H. S. Auvil, J. T. McCartney, J. D. Davis

"INTRODUCTION It is now generally recognized that the small-scale laboratory dilatometer method of test does not give results of much utility in predicting the expansion (or contraction) of a coal in a coke oven. The carbonizing conditions in the laboratory test differ radically from those in the oven; in this test, the charge is heated through the coking range of temperature as a whole, whereas in the oven, coking proceeds by layers parallel to the oven walls as each succeeding portion of the charge goes through the plastic range of temperature and coke formation sets in. The paths of the gases and vapors and the pressures set up are different in the two methods. Furthermore, the rate of heating in the test usually is much more rapid than in the oven. H. Koppers 5/ was perhaps the first to adopt apparatus and procedure whereby the layer coking of the coke oven could be simulated closely however, the heating progressed from one side of the charge only; later he experimented with a small coke oven with a movable wall heated from both sides. It is not clear how well the results in the later oven correlated with those of the earlier small test oven, but in a comparatively recent Koppers publication a modification of the original small test oven heated from one side is recommended 6/ Altieri 7/ was perhaps the first to experiment with the Koppers type small test oven in the United States and Brown- has tested a large variety of coals in a rectangular test oven of his own design heated from the sole or floor. Subcommittee XV of American Society for Testing Materials Committee D-5 is now making a study of the various methods proposed for determination of expanding and plastic properties of coal with a view to standardization. 9/"

May 1, 1939

By Michael Hood

High-volume, low-pressure water jets have been employed for erosion of loosely consolidated rocks for centuries. This excavation method finds application in specialized circumstances even today. The use of high-pressure, low-volume water jets for rock cutting is more recent and was made possible by the development of high-pressure water pumps. Despite the benefits often claimed for these systems, high-pressure water jets still have not found widespread application. In this report, the U.S. Bureau of Mines has reviewed the various methods that have been employed using water jets to break rock and has focused on one method, termed "jet-assisted cutting," which was determined to be the closest to commercial development. The current state of knowledge based on laboratory and field experiences using this cutting method is reviewed, and possible future developments for this approach to excavation are assessed.

Jan 1, 1990

By David A. Benjamin

The USBM (U.S. Bureau of Mines) studied mines, prospects, and mineralized sites in the Roberts WSA (Wilderness Study Area) in 1984. The 15,090-acre WSA, located 35 miles northwest of Eureka, NV, is underlain by alluvial deposits of Quaternary age, extrusive and intrusive volcanic rocks of Oligocene through Miocene age, and metasedimentary rocks of Cambrian through Permian age. The Roberts Mountain Thrust fault cuts through the WSA, dividing the metasedimentary rocks into upper and lower plate rock units. One mine, the Kelley, which produced 397 tons of lead-zinc ore prior to 1940, and two prospects are within the WSA; no resources were identified. Exploration for precious metal deposits is presently being conducted in and adjacent to the WSA on large claim blocks. The study area contains six sites in and near these claim blocks that have anomalous gold and silver. Detailed exploration is needed to delineate resources. High purity silica rocks are present in the WSA. Barite, phosphate, oil shale, and vanadium occurrences just outside the WSA may extend into it, but no such occurrences were observed during the USBM study.

Jan 1, 1986

By J. A. Eisele

The Bureau of Mines is investigating the recovery of alumina from domestic nonbauxitic resources, including anorthosite. The United States has large reserves of anorthosite, but its aluminum content is less than 50 pct soluble in acid, unless a source of fluoride is added to the acid. A flowsheet that includes leaching with HCl and fluoride followed by crystallization of AlC13.6H20 from the pregnant liquor by HCl gas injection was designed. Approximately 90 pct of the aluminum values were recovered from the anorthosite when a ratio of 0.14 mole of fluorine per mole of aluminum was used. Sodium chloride is cocrystallized with the A1C13.6H20 but is removed by water washing of the Al203 product. A material balance is given based on results of laboratory studies of the unit operations.

Jan 1, 1983

By L. Allan White

Instrumental analysis is an indispensable tool to many phases of research on rare-earth metals and their compounds; therefore, the development of new and improved instrumental techniques is essential. This report describes an emission spectrometric analytical method using direct-current carbon-arc excitation of various rare-earth-oxide mixtures. Lanthanum oxide serves the dual purpose of an internal standard and a constant major constituent. The versatility of the method was demonstrated by three different applications: (a) Analysis of complex rare-earth concentrates; (b) determination of impurities in high-purity rare-earth oxides; and (c) detection of rare-earth elements in other types of matrices, such as those resulting from beneficiation of rare-earth ores. The average error of analysis in the concentration range of 0.2 to 10.0 percent was 14.6 percent for a group of complex synthetic mixtures of rare-earth oxides. An average error of analysis in the concentration range of 0.05 to 0.50 percent was 21 percent for a group of high-purity rare-earth oxides.

Jan 1, 1959

By Michael G. Zabetakis, Glenn H. Damon, Joseph A. Herickes

The flammability and explosibility of unsymmetrical dimethylhydrazine ( UDMH ) were investigated by the Federal Bureau of Mines to evaluate hazards associated with commercial application of this material as a missile fuel . This program included the following determinations : 1. Temperature limits of flammability in air at one atmosphere pressure ; 2. limits of flammability at selected elevated temperatures and pressures ; 3. 4 . 5. spontaneous ignition temperature in air at one atmosphere and at 200 pressure per square inch gage ( p.s.i.g. ) initial pressure ; spontaneous decomposition temperatures in nitrogen at one atmosphere and at 200 p.s.i.g .; shock sensitivity over a temperature range from about ( ca. ) 25 ° to 50 ° C .; 6. shock sensitivity of reference propellants ( hydrazine , nitromethane , methyl acetylene , etc. ) ; 7 . shock sensitivity of UDMH plus small amounts of selected metal catalysts . Part of the corresponding data was obtained for a mixture of unsymmetrical - dimethylhydrazine and diethylenetriamine ( U - DETA) .

Jul 1, 1960

By Ronald A. Vary

This paper is one of a series prepared by the United States Bureau of Mines dealing with milling methods and costs. In view of the current revival of interest in gold mining, information dealing with practices and costs in the development of gold properties is apropos. Milling practice at a small gold property in the prospect stage is described where, with a small outlay for plant and equipment, development has been carried on for about 20 months on the proceeds of the mill operation with little additional expenditure. The paper shows about what may be expected as to costs at a small property operated under northern climatic conditions and with rigid economy throughout the plant.

Jan 1, 1931

By A. B. Coates

During the last three years the use of ethylene glycol dinitrate4 (E.G.D.) as at low-freeze (L.F.) agent in place of nitropolyglycerin has become common in the manufacture of explosives of the dynamite type. The usual proportion of D. G. D. in the explosive "oil" is 25 per cent; the remainder, 75 per cant, is regular nitroglycerin. These proportions were probably selected as a continuation of the practice of 25 per cent nitropolyglycerin and 75 per cent regular nitroglycerin.

Jan 1, 1929

By Wm. F. Netzeband

The purpose of this paper is to present to the operators, in other districts a detailed description of the ruining method used and the results obtained to exploiting one of the zinc-lead deposits of the Kansas-Oklahoma-Missouri district. No. 1. mine is located in the heart of the town of Picher in the extreme northeast corner of Oklahoma. HISTORY The first prospect drilling was done at No. 1 mine late in-1914, and shaft sinking was started early in 1915. Sufficient ore was developed to start construction of the mill in April, 1016, Production begin in August, 1916, and the mine s been producing, except for short periods, to the present time. The property was originally a 40-acre tract, but additional properties have been consolidated with the original one until the mine now covers 200 acres.

Jan 1, 1929

By Oliver C. Ralston

The growing popularity of perlite (sometimes spelled pearlite) as a raw material for thermal expansion into pumicelike products in the Western States has prompted a preliminary investigation of the properties of such material and the problems that want solution to put a perlite industry on a firm foundation. The Bureau of Mines is undertaking the gathering of data and the solution of these problems, and the following paper records some of the available information. and the promise of the material, with some comparisons of advantages of the various competing lightweight aggregates that can be made from siliceous volcanic glasses and rocks containing entrapped or dissolved water that causes their expansion on&apos; quick heating to their softening points. This new industrial rock has caught the fancy of the mineral industry in the western States because it has Fume advantages over natural pumice. Chemically, it is typified as rhyolitic in composition, and one may find obsidian, rhyolite, pumice, pumicite, and perlite from the same vant and contemporaneous in origin. The material need not be rhyolite but should be a siliceous or acid lava and contain 2 to 5 percent water still in "solution" in the rock. On quick heating to the softening temperature the material puffs, due to conversion of the contained eater into bubbles of steam. Slow heating causes gradual release of the imprisoned water by decrepitation and. cracking and-results in, very little puffing. Perlite is often in the form of ovoid volcanic bombs formed by explosive eruption of large masses of lava into the air, where they, quickly cool, with escape of little of the contained water, exceptt perhaps for a hollow interior. Since they cool in layers they have an onion-type structure and a pearly luster from interference of light between the. layers, which is&apos; the origin of the name "perlite." Perlite may occur in intruded flows that have been quickly cooled and partly expanded but retained most of their magmatic water content. Obsidian may be the same lava cooled quickly under conditions that prevented crystallization of feldspars and other minerals, leaving the volcanic glass that may or may not retain all of the original contained water.

Jan 1, 1946

By John Nagy

Tests were conducted in the Experimental coal mine to study some of the factors that should be considered in fighting mine fires and to obtain data on the effectiveness of different types of extinguishing agents. The investigation was confined to class "A" fires in a zone 20 feet long, involving coal burning on the floor, on the floor and ribs, and on the floor, ribs, and roof of the mine entry. It was determined that the time elapsed between ignition and attack of the fire is very important. A fire in the early stages was found to be controlled more easily and quickly than a similar fire that had burned longer. It was also found that, under suitable conditions, a fire in the floor, ribs, and roof develops very rapidly and consequently might spread over a considerable area if not brought under control quickly. The ventilating current affects fire-controlling operations markedly. Attack in intake or fresh air is highly advantageous, the chief inconvenience being the radiant heat from the fire. Attack in direct return air was impossible for the fires tested in this investigation, because of the high temperature. Universal-type gas masks for noxious gases and smoke offered no protection against the intense heat. Approach to a fire in the return air behind a water-fog curtain is not feasible unless the direction of air flow can be reversed. In one" test fresh air was carried to the fire area with a line brattice. Although the entire controlling operation was in fresh air and masks were not necessary, it was considerably more difficult to control the fire than when a similar fire was attacked in intake air.

Jan 1, 1950

By R. W. Stahl

Gas accumulation and dust suspension are the major safety hazards in coal stockpiling and reclaiming operations. This report presents a schedule of safety precautions and plant design features devised by the Bureau of Mines to reduce danger from these and other sources.

Jan 1, 1965

By L. C. IlsLey, H. H. Clark

As part of its investigations of the causes of mine accidents and of the safest and most efficient methods of handling electricity underground, the Bureau of Mines undertook a study of the ignition of mine gases by the filaments of electric incandescent lamps. This bulletin describes the investigation in detail and gives a complete record of the results obtained.

Jan 1, 1913

By Debra A. Griffith

The U.S. Bureau of Mines currently is researching the relationship between the level of back strength and the probability of low-back injury. This report is a review of the literature and statistics on over-exertion injuries. Overexertion continues to be a significant source of injury in metal and nonmetal mining, accounting for approximately 24 pct of all injuries yearly. These injuries, particularly to the lower back, can be very expensive in human and monetary terms. An examination of the accident data on overexertion injuries is necessary to provide a background for research into prevention and/or amelioration of those in-juries. The job categories outlined in the Accident Data Analysis data base most affected are "Mechanic/Electrician" and "Mill/Plant Worker." The age group most affected is "30-39" years, and the experience group most affected is "0-.99" years. The most prevalent type of overexertion injury is "Strain/Sprain," and the trunk is the body part most often involved in an overexertion injury.

Jan 1, 1994

By J. E. Schiller

The Bureau of Mines is investigating methods to treat waste water that contains cyanide. This report describes a new method that removes heavy metals and all forms of cyanide. In the first step, hydrogen peroxide and sodium thiosulfate are added at pH 7 to 9 in a 1:2 molar ratio to convert free and weakly complexed cyanide to nontoxic thiocyanate. Then steryldimethylbenzylammonium chloride is added to precipitate ferro-cyanide, and finally, ferric sulfate is added as a sweep floc and sequestrant for heavy metals. After the suspended solids settle, the water is polished by filtering. The water initially contained 1 to 5 mg/L Fe, 1 to 5 mg/L Cu, and 10 to 30 mg/L total cyanide; the level of each of these constituents was reduced to less than 0.02 mg/L.

Jan 1, 1983

By J. E. Wilson

A bench-scale expansion tester using 71 grams of coal was developed to determine the practicability of an apparatus of this size to investigate the effect of variables such as oxidation, blending, bulk density, inerts, size consist, petrographic differences, and rate of heating on the expanding properties of coal. The value of this tester is shown by the correlation that exists between its results and those of the larger scale sole-heated oven expansion apparatus used in commercial plants. From tests on 32 coals the standard error of estimate for predicting sole-oven results from bench-scale results is ± 5.3 percentage points. A standard deviation of the difference between pairs of tests in the latter apparatus of ± 2.1 percentage points was determined for 31 samples. In the sole-heated oven test the expansion of a coal at constant pressure is directly proportional to the dry coal bulk density. Tests in the bench-scale tester show a similar relationship between expansion and bulk density. When the blending ratios of high-and low-volatile coals are varied, similar changes in expansion are observed in both the sole-heated oven and the bench-scale tester. Therefore, the effect of other variables on expansion should be similar in the latter apparatus.

Jan 1, 1960

In presenting this list of permissible explosives and blasting devices, the Bureau of Mines desires to call attention to pages 19 and 24 outlining, the conditions in use under which, and only under which, the explosive or blasting device is permissible. In view of a recent publication recounting trade practice favoring the use of a blasting device without stemming, particular emphasis is placed upon condition 4 on page 19 and condition 2 on page 24. An explosive or a blasting device enumerated in the permissible lists of this Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming.

Jan 1, 1940

In presenting this list of permissible explosives and blasting devices, the Bureau of Mines desires to call attention to pages 19 and 24 outlining, the conditions in use under which, and only under which, the explosive or blasting device is permissible. In view of a recent publication recounting trade practice favoring the use of a blasting device without stemming, particular emphasis is placed upon condition 4 on page 19 and condition 2 on page 24. An explosive or a blasting device enumerated in the permissible lists of this Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming.

Jan 1, 1940