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By O. C. Blade

This report on the properties of aviation gasolines and aviation jet fuels produced in the United States during 1956 was made under a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. Analytical data are presented for 120 samples of aviation gasoline and for 38 samples of aviation jet fuel. The analyses were made on samples typical of the manufacturers' 1956 production in their laboratories and the results submitted to the Bureau of Mines for compilation. The products of 20 manufacturers of aviation gasolines and of 17 producers of aviation jet fuels are represented.

Jan 1, 1957

By M. R. Geer

The cleaning of fine coal, particularly for metallurgical use, is receiving greater attention. An increase in the proportion of fine coal in the run-of-mine product has been created by changes in mining practice, and a concur-rent deterioration in the quality of the fines has occurred because of more widespread full-seam mining. These two factors, augmented by the depletion of premium beds of metallurgical coal in some areas and the resulting shift to "dirtier" beds, are providing the impetus for adoption of improved cleaning techniques. For example, froth flotation, which has been used for years in a few preparation plants, now is gaining more rapidly in acceptance. Similarly, the dense-medium cyclone, which is used widely in Europe for making difficult separations, recently has been introduced to the United States. Regardless of the cleaning process employed, the finer sizes of coal can be treated with maximum effectiveness only when they are removed from the run-of-mine product and treated separately. No present process can treat the full range of sizes together with complete effectiveness. Flotation is applicable only to the coal finer than a top size ranging between 14-and 48-mesh, and cyclones require removal of all material finer than 0.5 to 0.3 mm. from the feed. Thus, the trend toward more-effective cleaning of the fine coal imposes the attendant problem of fine screening. Whereas in the past there was little need to screen finer than about l/4-in., present developments indicate that fine screening will become increasingly prevalent.

Jan 1, 1960

By Raymond L. Lowrie

Coal deposits in the Boulder-Weld County coalfield in Colorado are analyzed in relation to economic factors governing the growth, stability, and competitive potential of the coal industry. Recoverable reserves, estimated to be 571 million tons, are discussed in detail, particularly those in the Erie and Frederick Quadrangles. Geology of the coal measures, quantity and quality of water resources, and chemical and physical properties of the coal are described. Coal production factors, including mining techniques and equipment, labor requirements, transportation facilities and rates, and markets, are considered for coal's position in competition with alternate fuels. Growth of the fuels market, through increasing thermal-electric power generation in the Denver Metropolitan Area, will stimulate coal production in Colorado. Reserves of the contiguous Boulder-Weld coalfield, if mined in a sustained, year-round, high-tonnage operation, could be used to supply much of that fuel demand.

Jan 1, 1966

By D. W. Frommer, L. Bonicatto, M. M. Fine

A mineral - dressing investigation was conducted to demonstrate the ability of an anionic silica - flotation process to produce high- grade concentrates from submarginal iron ores of the western Mesabi and Menominee ranges . Commercially available equipment and reagents were used . Samples from the Menominee range were exclusively from the Groveland , Mich . , mine and contained hematite as the chief iron - bearing mineral . Bench- scale investigations established that the anionic silica flotation method can function effectively on a variety of undeslimed ores . Continuous tests completed on one Mesabi semitaconite ore and on Groveland mill feed , have verified the validity of the bench research . The Mesabi samples yielded a concentrate containing 60.3 percent Fe and 6.0 percent Sio with an accompanying iron unit recovery at 90.5 percent . Iron recoveries from the mill feed ranged from 79.0 to 87.4 percent .

Jan 1, 1964

By Ervin P. Fuchs

Volume II of this report presents the vibration data, octave band data, one-third octave band data and narrow band (amplitude versus frequency) data for ten mining machines. These ten mining machines include a Goodman 968-2 Loading Machine, a Lee Norse 245 Continuous Miner, a Jeffrey 120L Continuous Miner, a National Mine Service 3080 Continuous Miner, Acme D-1 Roof Bolter, a Lee Norse 265 Continuous Miner, two Jeffrey Locomotives, a Joy CD-71A Coal Drill and a Jeffrey 100L Auger Miner. Volume J of this report presents the effects of underground environment and loading conditions on noise levels of coal mining equipment

Jan 1, 1979

By E. J. Lintner, J. R. Thoenen

During the period 1937-40 and until peacetime research was superseded in 1941 by wartime activities , the junior author was engaged in studies regarding the relative efficiency of operating methods in quarries producing crushed stone for mineral aggregates . The results of some of these studies were published as reports of investigations in 1939 and 1940 ; / others were discontinued due to war demands on personnel and time . The published reports discussed the efficiency of particular quarry operations with respect to the time consumed and without reference to costs or mechanical factors . • At the time , the field data were collected for the published reports other data were collected relative to the relationship of the numerous variable factors inherent in the operation of a churn drill to the ability of the drill to produce blast holes . The churn drill is essentially a crusher and depends. for its performance upon the foot-pounds of energy it can impart to the cutting edge of its bit . The gravity stamp mill , so well-known in western gold mines , is essentially the same type of crusher . The ratio of foot- pounds necessary to crush the rock , to the total theoretical energy developed by the falling churn- drill tools , affords a good means of evaluating the efficiency of the tool . This does not include to tal over-all efficiency involving the mechanical equipment of the drill itself or its power unit .

Jan 1, 1947

By Raymond P. Maloney

The Bureau of Mines investigated the White Mountain mercury deposit, in the Kuskokwim River Basin, to better determine the extent of mercury mineralization and to encourage its development by private industry. A program of diamond drilling, augering, bulldozer trenching, and sampling was carried on during four field seasons, from 1960 to 1963, inclusive. Significant amounts of cinnabar, with only trace amounts of arsenic and antimony, occur in dolomite over an area about 4,000 feet long and 1,500 feet wide. The deposit differs from other mercury deposits in the Kuskokwim River Basin by the absence of silica-carbonate and rhyolite intrusives. Small-scale mining was started in 1963 as the result of Bureau investigation and continued during the summers of 1964 and 1965. The investigations indicate that open pit mining might be the most feasible method of working this deposit.

Jan 1, 1967

By K. O. Bennington

The thermodynamic properties of hedenbergite, of composition [(Ca0,9516) (Mg0,0583Fe2+0.7134 Fe3+0.0934 Mn0,1366) (Si206)], were experimentally determined at the Bureau of Mines. The standard enthalpy of formation determined by hydrofluoric acid solution calorimetry is AHf298 = -680.96±0.855 kcal/mol. The standard enthalpy of formation from the oxides is AR-96 = -24.55±0.485 kcal/mol. Low-temperature heat capacities were determined by adiabatic calorimetry from 12.3 to 300.1 K. The derived standard entropy is S-98 - 41.218±0.148 cal/mol-K. High-temperature heat capacities were measured with a differential scanning calorim¬eter from 397 to 1,147 K. These experimentally determined data were combined with data from the literature to calculate the Gibbs energies of formation and equilibrium constants of formation over the temperature range of measurements. Standard enthalpies of formation are given as a function of temperature. The standard Gibbs energy of formation at 298.15 K is AGf298 = -641.90±0.86 kcal/mol.

Jan 1, 1984

By R. R. Wells

As a part of the strategic minerals program of the Bureau of Mines, nine chromite-ore samples were obtained during the period 1949-56 from mines in the vicinity of Red Mountain, near Seldovia, Kenai Peninsula, Alaska. This report summarizes the results of beneficiation studies of the samples at the Bureau's Juneau, Alaska, and Albany, Oreg., laboratories. In general, the ores were found amenable to concentration by gravity methods for producing concentrates that assayed over 48 percent chromic oxide. Intimate association of chromite and gangue minerals, however, necessitated fine grinding and limited the amount of chromite recoverable. Recovery of chromium in concentrate that assayed 48 percent chromic oxide or higher ranged from approximately 20 percent for low-grade ores (10 to 12 percent Cr203) to more than 95 percent for 1 high-grade sample (42 percent Cr203). The iron content of the chrome-bearing mineral -hence, the chrome/iron ratio of finished concentrate -appears to vary with the grade of the ore. Concentrates made from high-grade ores had chrome/iron ratios as high as 3.1:1; the concentrates from low-grade ores, however, had chrome/iron ratios as low as 1.8:1.

Jan 1, 1957

By Kenneth J. Miller

The Federal Bureau of Mines coal-pyrite flotation process has been modi¬fied to produce a concentrated final clean coal slurry underflow that could be dewatered more effectively by filtration or centrifugation. This change was accomplished by redesigning the Bureau's two-stage flotation pilot plant facility and running the second-stage flotation step with undiluted or only partially diluted first stage coal froth concentrate. Results of the pilot plant flotation tests showed that substantial sulfur reduction could be achieved by flotation with undiluted pulp but some dilution is recommended for maximum selectivity. For example, coal-pyrite flotation in slurry of 25 percent solids yielded clean coal products analyzing as low as 0.7 percent pyritic sulfur and froth reject products containing slightly over 3.0 percent pyritic sulfur. In comparison, coal-pyrite flotation with pulp diluted to about 12.5 percent solids yielded clean coal containing as low as 0.4 percent pyritic sulfur and froth reject of 5.6 to 6.7 percent pyritic sulfur. Despite the need for some dilution, it was concluded that excellent coal-¬pyrite flotation selectivity could be achieved without diluting to 6 or 7 per¬cent solids as done in the earlier work. Thus the economics of coal-pyrite flotation would be improved by easing clean coal dewatering problems and by reducing second-stage flotation cell volume requirements.

Jan 1, 1977

By D. A. Reynolds, J. D. Davis

During early development of the blast furnace, Connellsville coke made entirely from Pittsburgh-bed coal proved to be an excellent fuel. The need for blending coking coals arose as the industry grew and it became necessary to carbonize coals having voking properties inferior to those of Pittsburgh coal Most coals carbonized today in continental Europe and this country are blonded: This practise has improved the quality of coke and permitted the utilization of coals that would yield inferior coke, if carbonized sepa- rately, The depletion of the world's better coking coals, which has been noted by leading coal technologists,2/4/wes accelerated during the recent war and. It is important, therefore, that reserves be evaluated and conserved. In the principal, steel-producing sections of this country, Pocahontas coals have been blended so extensively that the terms "low-volatile coking coal": and. "Pocahontas" have become virtually synonymous. Other low-volatile coals. have been used to manufacture metallurgical coke and will be used more extensively as, the supply of the better known and more accessible Pocahontas coals decreases. Recognizing the need for augmenting the supply of high-rank coking coals, the Bureau of Mines has included both low- and medium-volatile coals in its Survey of the Carbonizing Properties of American Coals, which was started with the cooperation of the American Gas Association in 1929. Twenty coals, 12 of low-volatile and 8 of medium-volatile rank, have been blended with high-volatile A Pittsburgh-bed coal, and five standard low- volatile coals have been blended with various high-volatile coals. Most of the results of carbonization tests of these coals and their blends have been

May 1, 1946

By J. Hyvarinen, A. D. Look

"INTRODUCTION AND SUMMARYElectricity is used extensively in open-pit metal mines to provide illumination, heat, and power to operate hauling and loading equipment, drills, pumps, signal systems, and other machinery. Good installation and maintenance of equipment and power, circuits, are essential to minimize the hazards of shock, burns, and fire.In the 13 years from 1931 to 1943, 20 fatal and 82 nonfatal injuries resulted from the use of electricity in open-pit mines in the United States ; 4/ these figures represent about, 10 percent of all fatalities and 1 percent of the nonfatal injuries. The ratio of fatal to nonfatal injuries from electricity in such mines was very high during this period; the figures show one fatality to every five accidents from this cause.Electricity may cause personal injury through abnormalities in equipment, such as short-circuit, accidental ground, overload, and poor contact; however, each year some fatal electrical accidents are due to persons touching uninsulated ""live wires."" These contact injuries are the result of careless body movements of persons in the vicinity of 'wires at places not normally frequented, or of accidental contact with live circuits when handling metal objects. Electrical hazards can be minimized by the enclosure or elevation of current-carrying parts; ample working space around equipment, adequate insulation, locking switches in the open or closed position under certain conditions, identifying and warning devices, protective grounding, insulating flooring, platforms, or rubber gloves, and proper inspection and maintenance."

Apr 1, 1949

By A. W. Deurbrouck

This report describes the preparation characteristics of the significant coalbeds from which samples could be obtained in Webster County, W. Va. In 1964, approximately 825,000 tons of coal was produced in the county, of which 732,000 tons was mechanically cleaned in three preparation plants. The Sewell coal bed accounted for 94 percent of the coal produced. Twelve samples were collected from five coalbeds. Four of the samples would require upgrading to meet metallurgical requirements; two others of just over 8.0 percent ash would require some upgrading. In general the coalbed samples collected in the county were of medium-sulfur and medium-to low-ash content as received or after removal of the sink 1.58-specific-gravity material.

Jan 1, 1966

By J. E. Hamak

This publication contains analyses and related source data for 266 natural gas samples from 20 States and 2 foreign countries. None of the analyses have been previously published in annual reports. All samples were obtained and analyzed as part of the U.S. Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1992

By Albert W. Deurbrouck

The performance of four sand cones was evaluated by the Bureau of Mines in three preparation plants that utilized cones in various flow schemes. The cone at plant A was a simple two-product one that provided clean coal and refuse. Plant B had two cones; one cone made a primary separation and the other a secondary separation. The primary cone separated salable coal from heavy rejects. The secondary cone separated a low-ash metallurgical coal and an intermediate-ash product suitable for plant fuel or steam markets. In plant C the sand cone was equipped with a middlings draw Which continually removed an intermediate specific-gravity product below the surface of the cone. The three primary separations of raw coal effected between floats and sinks were excellent. The recovery efficiencies for the plus 1/4-inch material ranged from 99.8 to 97.6 percent, the error areas ranged from 19 to 23 square centimeters, and the probable errors in specific gravity ranged from 0.033 to 0.024. The performance data of the two secondary separations varied from excellent in plant B, where the separation was on a par with the primary separations, to somewhat inferior in plant C, where the secondary separation was effected at the middlings draw.

Jan 1, 1965

By Raymond W. Hiteshue, Sam Friedman, Robert Madden

Experiments were made in a semicontinuous unit to provide engineering data for designing experimental continuous systems . These systems would be used to study the hydrogasification of hvab coal and char (from lowtemperature carbonization ) to high - Btu gas . In experiments at 800 ° C and with a coal residence time of several seconds , yields of hydrocarbon gases increased from about 2,000 scf / ton of maf coal at 250 psig to 7,000 scf at 1,000 psig . With 15 minutes residence time , yields increased from 8,000 scf/ton of maf coal at 250 psig to 17,500 cubic feet at 1,000 psig . In all cases , small quantities of heavy oils were produced along with the gaseous hydrocarbons . Production of oils could be minimized with a corresponding increase in gaseous hydrocarbons by increasing the retention time of the volatiles within the hot zone . Yields of gaseous hydrocarbons from char were slightly greater than from coal under similar conditions . Although the hydrogasification reaction is very pressure dependent , substantial quantities of coal (40 to 60 percent ) could be reacted to gaseous hydrocarbons at pressures as low as 50 psig provided reaction temperatures were increased to 1,200 ° C. It was also demonstrated that a hvab coal could be hydrogasified continuously without incurring agglomeration . This was achieved by dispersing coal in a relatively large reactor with concurrent flow of hydrogen . At 1,000 psig and 800 ° C , it was possible to react about 35 percent of the coal and to produce a gas containing up to 52 percent methane .

Jan 1, 1964

A study was conducted by the Bureau of Mines to evaluate natural gas as an automotive fuel and to provide guidelines for optimum engine adjustments for low exhaust emissions. The study was conducted using a single-cylinder engine, a multicylinder engine, and a total of eight vehicles. Results from single-cylinder engine tests showed that the light-load, lean-limit misfire region for natural gas begins at an air-fuel ratio between 150 and 160 pct of stoichiometric. Changes in ignition timing significantly influenced emissions of nitrogen oxides and hydrocarbons, but had little effect on carbon monoxide emission. Low emissions can be achieved with current-design engines by adjustment of engine parameters, but only with heavy penalty to engine performance. Emissions from vehicles fueled with natural gas are virtually unaffected by ambient temperature change within the range 20° to 100° F. The organic emissions from engines fueled with natural gas were estimated to be 22 to 25 pct as reactive as the emissions produced using gasoline. Levels of exhaust emissions from vehicles fueled with natural gas were unchanged over 10,000 miles of normal driving.

Jan 1, 1973

By Eric R. Bauer

The ground control aspects of extended depth-of-cut mining are presented in this U.S. Bureau of Mines report. A trend analysis of extended cut approvals was performed. A comparative review of roof fall fatalities for extended and nonextended cut mining is included. Current ground control guidelines for extended cut approval are summarized. The problems and concerns of this extraction system are addressed, and typical extended cutting face operations are described.

Jan 1, 1993

By Jr. Karr

The Bureau of Mines studied the influence of carbonization method, temperature, and carrier gas on the composition of eight different low-temperature tars produced from a Colorado subbituminous coal. A fluidized bed was compared with an entrained bed, temperature was varied from 500° C to 650° C, and external heating using recycle gas as the carrier gas was compared with internal heating using oxygen-containing gas. The entrained bed yielded significantly more m-cresol and m-ethylphenol, indicating that thermodynamic equilibrium was more nearly approached in the system. Increasing the temperature greatly increased the yield of benzenes and naphthalenes, while paraffins, olefins, and total tar acids were reduced. Using oxygen in the carrier gas decreased the yield of low-boiling phenols and increased that of paraffins and olefins at 650° C.

Jan 1, 1966

By Marting J. Gavin

The twentieth century has often been spoken of as the age of petroleum, and from many viewpoints it can be justly considered so. Certainly the petroleum industry is one of enormous importance to this country, industrially, financially, and economically. The United States, however, at present producing over 60 per cent of the world's total output of petroleum, is not producing petroleum at a sufficient rate to provide for its own domestic, consumption. For several years this country has been importing increasing quantities of crude and partly refined oils from Mexico, and has been drawing heavily on domestic stocks of petroleum. Production in the United States is increasing, but it is not increasing at the same average rate as domestic consumption, nor is it probable that in the future domestic production will increase sufficiently to satisfy the demands of domestic consumption, but on the contrary, in the opinion of those best qualified to know, the peak in the curve of domestic production of crude petroleum will be reached in a comparatively few years, whereas the consumption of petroleum and its product will increase at a continually growing rate. This country, then, must turn, and as the increasing imports from Mexico indicate, is turning to other sources than the crude petroleum, produced in this country to make up the deficit between domestic production and domestic consumption of petroleum and its products,

Jun 1, 1920