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By I. N. Beall

The present survey indicates 'that the average volatility of motor gasoline now being marketed throughout the country falls well within the limits of Federal Specifications. As would be expected, there is a slight decrease in volatility as compared with the gasoline marketed last wine:., but on the average the gasoline sold today is about the same as that sold last summer. During the past five years the Bureau of Mines has made semi-annual surveys of the gasoline marketed in the United States. To obtain a sample of each gasoline sold is obviously impracticable, but the cities in which samples have been collected have been so chosen as to be representative of the more important marketing territories. It is believed, therefore, that the samples obtained are indicative of the quality of gasoline marketed throughout the country.

Jan 1, 1925

To precondition a stope in advance of mining and thus reduce or prevent rock bursts. Approach Drill deep holes from a mine opening in a radial pattern in the vein and load and blast to fracture, the rock prior to production mining How It Works Preconditioning of a sphalerite galena vein in a hard gangue of quartz and quartzite creates a zone of softer rock that fails by displacement rather than violently as an elastic-battle mass. However, the entire area must he analyzed carefully so that the stress transfer does not cause problems in other workings of the mine A typical drill hole pattern and explosive loading is shown in the sketch. Hole diameter is about 4 inches and a down-the-hole, type drill is used. Drilling speed in hard quartzite is about 12 inches per minute High pressure compressed air (250 psi) is used to run the drill. An overhand cut-and-fill stoping area on the 7700 level of Hecla Mining Company's Star Mine in Burke, Idaho was preconditioned above and below the

Jan 1, 1981

By J. Weinberg

This Bureau of Mines report presents data on the changes in the use of steel in motor vehicles over the past 35 yr. Sources of supply of steel for the automotive sector have shifted from almost all domestic in the 1950's to about 50% domestic and 50% foreign in the 1980's. Downsizing, design changes, and substitution of lighter weight materials to achieve energy efficiency also contributed to the market loss of the domestic steel industry. Although plastics and aluminum have displaced some steel in motor vehicles over the years, heavy low-carbon steel is now being replaced most rapidly by lightweight high-strength steel. If the percent of domestic steel used in motor vehicles had not declined since 1950, domestic industry would have supplied 9.3 million more short tons of steel than it supplied in 1985. Downsizing and design changes accounted for 43% of the loss; steel imports, 32%; and substitution of plastics and aluminum, 25%. In 1985, the total value of market share lost by U.S. steel producers was $5.1 billion, of which $1.6 billion was lost to foreign steel producers and automobile manufacturers. Through aggressive marketing and increased efficiency, however, the domestic steel industry may be able to recapture some lost markets, as applications for high-strength steels expand, and as foreign-owned automotive plants in the United States provide fresh sales opportunities.

Jan 1, 1988

By Thomas J. Peters

The U.S. Bureau of Mines studied the 63,9SS-acre Hanson Lakes study area, including the Ten Mile-East and part of the Ten-Mile West RARE II areas, plus additional acreage, all proposed at times for Wilderness designation. The study was part of a Idaho Land Assessment Program with the Idaho Geological Survey and the U.S. Geological Survey, to provide minerals information for land-use decisions, and ensure domestic mineral supplies. The area is at the north end of the rugged Sawtooth Range and includes parts of the Sawtooth National Recreation Area which is closed to mineral location. The Copper Mountain. Elk Mountain, and Observation Peak mineralized areas are in the study area, but only Copper Mountain is open to claim location. It is on the trans-Challis fault zone and contains Tertiary granite which is favorable for mineral deposits of gold, beryllium, niobium, REE (rare-earth elements), tin, molybdenum, copper, silver, and lead. Identified resources are 1.9 million tons of flake graphite at Elk Mountain, but much more graphite occurs in the vicinity REE occurs in 18 black sand placer sites along the lower reaches of study area streams just outside the study area, on Cape Horn Creek, Marsh Creek, and lower Valley Creek flood plains, and at one hydrothermal site near Observation Peak. Hydrothermal REE is commonly low in? by-product thorium. a radioactive disposal problem. Many advanced REE applications enhance the quality of life, and future uses in superconductivity may reduce energy consumption. Seventeen lode, one geothermal, and 11 placer prospects were examined. Workings totaled about 20 adits, one shaft, several open cuts, and numerous small pits. Approximately 500 mining claims have been located or relocated in the study area, including a 200-claim block for disseminated molybdenum.

Jan 1, 1992

By E. L. Rawlins

The Bureau of Mines, with the cooperation of the Natural Gas Association of America, has conducted a study of leakage losses from natural-gas transmission lines. This study has shorn that surveys to determine the leakage from transmission lines lead to line repair work that not only aids in the conservation of gas, but can be made to show financial returns of large magnitude.2 In order to conduct the study, it was necessary to develop accurate and reliable methods of determining the actual leakage from pipe lines. METHODS OF TESTING Three methods that were developed and used to determine the leakage losses from high-pressure natural-gas transmission lines are: (1) The "pressure-drop" method, (2) The "metering-in and metering-out" method. (3) The "metering-in" method.

Jan 1, 1926

By Alan D. Hartman

Standard metering of electric arc furnaces usually uses root mean square (RMS) or true root mean square (TRMS) measurements for determining power. Only sinusoidal signals are accurately described by RMS meters, and dc or high-frequency components normally are lost in standard TRMS metering. This can lead to inaccuracies when electrical signals are not sinusoidal, contain dc components, or include fast risetime perturbations, as is the case with the electric signals from an electric arc furnace. Electric arc furnace electrical waveforms, observed in research carried out by the U.S. Bureau of Mines, show high-frequency components and significant deviations from sinusoids. These perturbations and distortions make metering difficult for standard power meters. The inaccuracies in metering can cause further problems if those sensors are used in control systems. For control strategies requiring rapid response, any averaging scheme loses information that can be used in control decisions. In order to obtain better signals for both monitoring and control, a study of instantaneous, RMS, and TRMS power monitoring devices was conducted. From this study it was concluded that precision integrated circuits should be used to obtain instantaneous power with a bandwidth of at least 25 kHz. The information from these devices is more representative than that of standard meters and can be used in predictive control.

Jan 1, 2010

By Benton L. Tibbetts

Comprehensive geophysical measurements were made in the Tertiary Channel gravel deposits of Badger Hill, Calif., with the refraction seismograph, gravimeter, and well logging equipment, to develop a three-dimensional physical model of the gold-bearing gravels. Tests were also made of the applicability of magnetometer and electrical resistivity techniques. Results of 14 seismic profiles revealed four distinct layers with velocities of 1,600 ft/sec for loose gravel, 5,900 ft/sec for compact gravel, 8,600 ft/sec for cemented, blue gravel, and 15,500 ft/sec for bedrock. The depth to bedrock along the middle of the channel varied from a minimum of 100 feet in the hydraulically mined pit area to a maximum of about 300 feet in the upper bench area immediately south of the pit. These geophysical methods revealed that 40 percent of the drill holes necessary to delineate the deposit could be eliminated, at a cost saving of at least 30 percent.

Jan 1, 1971

By Michael G. Zabetakis

The autoignition temperatures (A.I.T.'s) of natural and synthetic lubricants in air were generally found to decrease with increasing pressure. Of the two types of fluids, synthetic and natural, studied in some detail, the phosphate esters had higher A.I.T.'s at any pressure between 1 and 200 atmospheres than the mineral oils. Most of the A.I.T. data obtained in this study obeyed the relationship predicted by Semenov's theory of ignition.

Jan 1, 1962

By B. J. Dalton

The Bureau of Mines Helium Research Center has developed a computer program for solving two-phase equilibria data for binary mixtures and for evaluating thermodynamic functions of interest, including all critical points. This computer program was used to calculate equilibrium points on the PVTu surface for the helium-nitrogen system as predicted by the Van der Waals equation of state. Numerical values are tabulated and illustrations are presented for 1,279 equilibrium points and for quantities needed to construct Ponchon diagrams. Equilibrium ratios as a function of pressure at constant temperature and of temperature at constant pressure-are also shown graphically. In addition, saturated partial molal volume and partial molal enthalpy data are given. It is shown that the Van der Waals helium-nitrogen system exhibits retro-grade condensation of the second type for liquid helium concentrations of about 0.07 mole fraction or less and pressures below about 45 atm. It is also shown that the critical point is at a -maximum value of pressure (at constant temperature) and of temperature (at constant pressure).

Jan 1, 1971

By M. L. Whisman

Radiotracer techniques were developed for stoichiometric studies of photochemical reactions associated with atmospheric smog formation. Stock blends of separate hydrocarbon and oxygenated compounds were prepared and calibrated. 14C-labeled reactants and products in reaction systems involving hydrocarbons and nitrogen oxides at the ppm level were analyzed for qualitative and quantitative data. Precision and accuracy of these methods developed by the Bureau were determined by replication and statistical treatment of data, and these methods are described.

Jan 1, 1969

By L. D. Schmidt, H. G. Graham

Several processes for the production of ultra-clean coal for electrode carbon were developed in Germany prior to and during World War II . These processes have been investigated since the end of the war by the British and U. S. Government missions . As the reports of the investigations are not readily available to the public , it is the purpose of this paper to present the information which has been obtained regarding the methods by which ultraclean coal was produced . Almost all the ultra-clean coal was used in the manufacture of electrodes for the production of aluminum and magnesium . Standard raw materials for making these electrodes are pitch coke and petroleum coke , which are nearly ashless . The inclusion of ash in the electrode carbon results in lowered efficiency and impure metal from the reduction process . Petroleum coke and pitch coke were in very short supply in Germany during the war , so that it was necessary to augment the supply with carbon produced from coal . In the emergency , methods were developed to clean coal which had never before been economically feasible . However , a demand for nearly ash-free coal might develop in the United States if a shortage of petroleum coke were to occur at the same time as a strong demand for light metals . Other uses of ultraclean coal are in direct hydrogenation of coal , in production of activated carbon, and for special fuels . Specifications for electrode carbon are rather severe owing to the necessity for producing pure metal . Maximum amounts of impurities allowable in American practice are as follows : Total ash , 1.0 percent ( in finished coke , 0.7 percent ) Silica , 0.08 percent Ca or Na, or their sum , 0.12 percent Sulfur , 2.0 percent Ba , Ni , Cr , Mn , Co , and V are objectionable in very small amounts . The most important process for ultra cleaning of coal in Germany was froth flotation . Froth flotation had been used widely there to process washery -water sludges and to recover coking coal from high - ash fines . Its use was indicated , therefore , when the demand for ultra low-ash coal arose . In two plants the coal cleaned by froth flotation was treated with acid or caustic to lower further the ash content . Another process used on an industrial scale was that of dissolving the coal substance in the middle oil from direct hydrogenation of coal under controlled pressure and temperature . The resulting paste was heated, filtered , and the oil distilled off . The residue was a low-ash organic material that could be carbonized for electrode carbon or could be hydrogenated directly . Several other processes had been developed to the laboratory or pilot - plant stage but had never been used on a commercial scale . These processes included cleaning by centrifugal action , cleaning by electrostatic action , and cleaning by forming a paste with oil in water . The coal-preparation plants at the Carl Alexander mine , Augusta Viktoria mine , and Kőenigin Elisabeth mine are described in Bureau of Mines Information Circular 7389 : " Coal Preparation Practice in Western Germany" , by Thomas . Fraser and M. G. Driessen . Most of the special equipment used at these plants is described in the above publication .

Oct 1, 1948

By Thomas C. Atchison, Joseph M. Pugliese

Six explosives were compared by measuring their strain- producing abilities in limestone . Peak strain , e , varied with scaled distance , R/Ro , according to the following equation : € = Kc (R /R 。)- ". The distance exponent , n , was a constant of the rock and did not depend upon explosive . The strain intercept , Ke , increased with increasing detonation pressure of the explosive . The strain intercept also depended upon the explosive- to - rock impedance ratio . For impedance ratios from 0.53 to 1.38 , the strain intercept was approximately proportional to the medium stress , Pn , as calculated from the explosive detonation pressure , P , and the explosive - torock impedence ratio , Z , by the simple elastic theory relation : P = 2P / ( 1 + Z ) . PD However , the data indicated that , at lower values of impedance ratio , the strain intercept is relatively larger than would be expected from the simple elastic theory . The results presented provide a simple method for predicting the relative effectiveness of different explosives in breaking limestone from the detonation pressures and characteristic impedances of the explosives .

Jan 1, 1964

By R. N. Love, L. Goldman

"INTRODUCTION When tannin is present in a boiler water, it causes certain difficulties in many analytical testing procedures because of its colloidal action in interfering with the removal of suspended matter by filtration and also because of the color it imparts to the boiler water.For example, in any test for phosphate in boiler water the first step is to filter out of the sample all sludge and suspended solids. Calcium phosphate in the sludge would give high results if not completely removed. If tannin is present in the sample, the sludge and suspended matter tend to pass through the filter paper so that it is difficult to remove it all. It may even be that tannin makes some of the suspended material in the sample completely nonfilterable. If this is true, it would be necessary to destroy or remove the tannin from the sample before filtering to get complete removal of calcium phosphate from the sample. In addition, if the test used is a colorimetric one, the tannin causes interference by its own color.As the calorimetric phosphate test is so convenient for control purposes and the use of tannin for boiler water treatment has become common, it has become necessary to develop suitable methods for employing the colorimetric phosphate test for boiler waters containing tannin. In this paper three different methods for doing this arc described and studied."

Oct 1, 1946

By R. J. Hundhausen

The Takilma-Waldo copper district in Josephine County, Oreg., was studied by the Bureau of Mines from September 1950 to April 1.951 and from December 1953 to April 1954. Funds for the investigation were provided by the Bureau of Mines and the California-Oregon Power Co., Medford, Oreg., on a cooperative basis. The copper mines in the district are credited with a total production of ore worth $1,700,000. Since 1933 the mines have been unproductive and, except for minor exploration, largely inactive. The history of the district indicates that the copper deposits were mined principally during periods of high metal prices.

Jan 1, 1956

By Charles F. Weber

Premature blasts of charges of explosives have caused many deaths in anthracite mines, and the causes of many of the blasts were not determined satisfactorily. Investigators often found fairly high potential differences between such metallic objects as rails, pipes, conveyor lines, or sheet-iron chutes in the working place where an accident had occurred. At one mine where a premature blast occurred in a rock tunnel, one workman was killed and two others were injured, and several days later a potential difference large enough to explode an electric squib was detected between the compressed-air pipe and the track rail; the voltage fluctuated and appeared to change with the movement of a locomotive. At another mine, a. workman was killed when a primed cartridge that he was about to load in a blast hole exploded in his hand. During the investigation, a potential difference was found between the conveyor line and the sheet-iron chute. During a 5-year Period, 61 fatalities and 771 nonfatal injuries were caused by explosives accidents in anthracite mines, and one of the chief causes of these accidents was premature blasts.

Jan 1, 1950

By J. A. Organiscak

The U.S. Bureau of Mines investigated the relationship of bituminous coal seam parameters and the amount of airborne respirable dust generated at longwalls. Dust and coal samples were obtained from 20 longwalls operating in geographically representative coalfields throughout the United States. Statistical analyses of coal seam parameters and airborne respirable dust measurements indicate a likely causal relationship between seam type and respirable dust. Low-ash, high-volatile coal seams were associated with higher airborne respirable dust levels. A negative linear correlation (significant at the 95-pct confidence level) was observed between the seam's ash content and airborne respirable dust, explaining up to 18 pct (R2 = 0.18) of headgate dust level variation and up to 15 pct of tailgate dust level variation. Volatile matter was found to have a positive linear correlation with tailgate dust level, explaining 16 pct of the variation. Further data examination indicates that these relationships with dust are most likely nonlinear, because of improved R2 values over the linear correlations. However, a notable portion of longwall dust production is influenced by other operational parameters, so additional research under more controlled conditions is needed to determine the seam's causative functions.

Jan 1, 2010

By P. L. Sibrell

Previous research by the U.S. Bureau of Mines has shown that autoclave cyanide leaching of used automobile exhaust catalysts for recovery of platinum-group metals (PGM) is technically feasible. The purpose of this work was to investigate the chemistry of the dissolution of PGM in cyanide solutions in more detail. Where possible, samples of pure, elemental PGM powders or foils were used instead of automobile exhaust catalysts, because of their greater purity. Ultraviolet spectra revealed that Pt and Pd were solubilized as the square planar tetracyanometallate (II) complexes, while Rh was solubilized as the octahedral hexacyanorhodate (III) complex. This explained the poor recovery of Rh from solution by carbon adsorption, solvent extraction, and ion exchange observed in earlier research, because of the higher anionic charge and size of the octahedral complex. Leaching rate studies showed that the rate of solubilization was greatest for Pd, followed by Pt and Rh. Although the rate of chemical reaction was the controlling step for the dissolution of elemental Pt and Rh samples, the rate of pore diffusion was rate limiting for PGM in catalyst samples.

Jan 1, 2010

By C. G. Kirkland

An apparatus for determining trace impurities in Grade-A helium by mass spectrometer methods was designed and built by the Federal Bureau of Mines. Grade-A is the designation for helium commercially produced by the Bureau. Its nominal purity is 99.995 percent. The device, following a suggestion by Deaton, concentrates the impurities in the helium by freezing them out in a coil-and-trap assembly cooled by liquid helium. A known volume of helium is passed through the trap, the concentration ratio determined, and samples of the concentrated impurities are analyzed by mass spectrometer methods. The apparatus has been in service for approximately 20 months and has satisfactorily met all requirements. Over 200 analyses were made of helium contained in conventional cylinders, obtained from the Amarillo, Exell, Otis, and Navajo Helium Plants, during the 6-month period ending March I, 1959. Total impurity concentrations, in parts per million, were as follows: Amarillo, 19.1; Exell, 17.1; Otis, 11.3; and Navajo, 6.6. Neon and nitrogen were the major impurities. Complete data are shown in table 4 in the body of this report.

Jan 1, 1960

By Ronald T. Mayerle

In 1989, the U.S. Bureau of Mines conducted a mineral investigation of the Mallard study area near Elk City, Idaho. The study area comprises most of the original Mallard RARE II area (1-847) plus some additional lands. The investigation is part of an ongoing, multi-year study of north-central Idaho that is being conducted in cooperation with the Idaho Geological Survey and the U.S. Geological Survey (USGS). The only identified resources are rock suitable for road metal. Five lode prospects and a pyrite-bearing rock quarry, which is operated by the Forest Service for aggregate, were examined for metals. One of the prospects warrants additional exploration for silver in quartz veins, but the chance of finding an economically minable deposit is limited. Several rock and stream sediment samples were anomalous in various metals. Two of the more promising localities for gold and/or other metals are adjacent to a unit of the Frank Church-River of No Return Wilderness that the USGS classified as having a moderate potential for gold deposits related to fossil hot springs.

Jan 1, 1991

By M. R. Geer

American and European practices in cleaning fine coal are strikingly different. The tables, launders, classifiers, and pneumatic devices used in America are seldom employed in Continental Europe, where much of the fine coal is cleaned in feldspar jigs, often supplemented by froth flotation of the extreme fines. This difference in choice of cleaning equipment may be fortuitous, but in large measure can be attributed to a difference in economic factors. Coal being more costly in Europe, there is greater emphasis on efficient cleaning of all sizes, including the extreme fines, and it is common to produce a high-ash middling for "on-site" consumption to avoid any waste of fuel value. The feldspar jig has been found advantageous under these conditions. In the United States fuel coal must be prepared as cheaply as possible, and metallurgical coal must be prepared as efficiently as possible; thus in both branches of preparation practice, any cleaning device that promises greater economy or higher efficiency warrants consideration. The feldspar jig, as employed in Europe, has a much higher unit capacity than the wet table used so extensively here and therefore offers economy in the capital costs of a washery through saving in space. As pointed out by Vissac,4/ the jig operates under automatic control, and therefore can cope with fluctuations in quality of feed. Maintenance costs for a single, large-capacity unit, such as the feldspar jig, would be expected to be lower than those for a battery of low-capacity cleaners. These considerations led the Bureau of Mines to undertake an investigation of the feldspar jig to determine its possible usefulness in this country.

Jan 1, 1958