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By Foster Fraas

The electrical conductivity of minerals increases with increase in temperature as a result of the thermal activation of the electrons. Some oxidizable minerals have a change in the stoichiometric proportions after heating in air, and the conductivity does not return to the original value after cooling. Similar changes occur in reducing atmospheres. Other minerals, such as carbonates and hydrates, are completely decomposed. Electrical resistivity measurements on single particles when compared to standard separation measurements show that minerals having resistivities above 1013 ohms respond as nonconductors. Those below 1011 respond as good conductors.

Jan 1, 1956

By Robert H. Peters

This report presents findings from a Bureau of Mines study on barriers that may prevent miners from correcting and avoiding groundfall hazards. Such barriers stem from four basic types of problems: (1) inability to recognize groundfall hazards, (2) inability to correct groundfall hazards, (3) lack of motivation to search for groundfall hazards, and (4) lack of motivation to correct groundfall hazards. Data are presented that summarize the views of miners, section supervisors, and mine inspectors about the contribution of these barriers to groundfall accidents and what they think should be done to reduce the frequency of injuries sustained by falls of roof and rib. The report also includes a summary of miners' responses concerning their recent experiences with groundfall accidents, along with industrywide statistics on accidents and injuries caused by ground falls in underground coal mines.

Jan 1, 1987

By H. W. St. Clair

This study of the rate of evaporation of zinc was undertaken as a part, of a general investigation on refining mixtures of metals resulting from melting reclaimed scrap. One of the methods by which the more volatile metals, such as zinc, magnesium, and cadmium, may be separated is by distillation. Distillation may be carried out at lower temperatures if it is done in an evacuated enclosure. The immediate purpose of the present investigation was to determine accurately the effect of temperature, pressure, and other factors on the rate of evaporation of zinc.

Jan 1, 1950

By E. C. Fitch

This report discusses fire-resistant hydraulic fluid safety from three different directions. First, results of a survey prepared for the Fire Resistant Hydraulics Journal by the staff of the Fluid Power Research Center are analyzed. Second, operational limitations of fire-resistant hydraulic fluids are examined. Finally, laws and standards of various foreign countries are investigated. Three conclusions are derived from a close study of fire-resistant hydraulic fluid safety from these three directions. First, a significant number of experts in the fluid power industry are no in agreement about aspects of fire-resistant hydraulic fluid fire-resistance and toxicity. This indicates a need for more in depth research. Second, the use of fire-resistant hydraulic fluids involves a compromise between the decreased fire hazards and increased toxicity and machine incompatibility problems. Finlly, major foreign governmental agencies have thorough laws and standards concerning fire-resistant hydraulic fluids. These laws and standards may provide a solid framework for further international research into fire-resistant hydraulic fluid safety.

Jan 1, 1979

By C. J. Wilhelm

Brine produced from subsurface formations may be employed successfully instead of fresh water as a flooding, medium in the secondary recovery of oil. The feasibility of this substitution has been proved in the shallow "shoestring" area of eastern Kansas and northeastern Oklahoma, where the supply of fresh water often is limited. In this procedure all brine produced with the oil is returned to the formation and thus is prevented from contaminating streams and fresh-water supplies. This report includes a detailed description of a "flood project" in eastern Kansas studied by the Bureau of Mines. In an attempt to determine whether brine, when handled properly, can be used as effectively as fresh water in flooding oil from partly depleted, formations, an analysis was made of all .own conditions that influence flooding.

Jan 1, 1941

By C. J. Wilhelm

Brine produced from subsurface formations may be employed successfully instead of fresh water as a flooding, medium in the secondary recovery of oil. The feasibility of this substitution has been proved in the shallow "shoestring" area of eastern Kansas and northeastern Oklahoma, where the supply of fresh water often is limited. In this procedure all brine produced with the oil is returned to the formation and thus is prevented from contaminating streams and fresh-water supplies. This report includes a detailed description of a "flood project" in eastern Kansas studied by the Bureau of Mines. In an attempt to determine whether brine, when handled properly, can be used as effectively as fresh water in flooding oil from partly depleted formations, an analysis was made of all known conditions that influence flooding.

Jan 1, 1941

By David D. Walker

The purpose of the investigation was to describe and appraise tungsten deposits in Montana . The work supplements previous investigations made by Pattee ( 10 ) and Walker ( 17 ) in selected areas of the State . Scheelite deposits in tactite are the most numerous and most important economically , having accounted for nearly all of the State's tungsten production . Of the 64 deposits examined during the current study , 50 contained scheelite , 11 hubnerite , 2 wolframite , and 1 ferberite . The State's major tungsten production has been from scheelite deposits in Beaverhead County . The report lists , by counties , the type and grade of each deposit . The more important occurrences are accompanied by geological and assay maps .

Jan 1, 1963

By M. R. Yenchek

The U.S. Bureau of Mines designed and constructed sensitive and coordination-free ground-fault relays (GFR's) for use on mine power systems. First, a list of GFR attributes for mine ac utilization applications was compiled. These practical guidelines specified design, construction, transient immunity, reliability, and operating criteria. The time-current characteristics of the ac and dc units, subsequently fabricated, were designed to be below the human electrocution threshold. The significant and highly variable capacitance of high-voltage distribution cables was found to preclude the sensing of ground currents in the milliampere range. However, the coordination-free system developed for high-voltage distribution should enhance safety by significantly decreasing response time to ground faults. Implementation of the sensitive GFR technology in the mining industry has the potential to eliminate the majority of injuries and nearly all the deaths resulting from contact with energized components.

Jan 1, 1990

By W. E. Robinson

Oil-shale kerogen was processed into oil and oil products before the first oil well was completed by Drake in 1859. However, because of economic and other advantages, natural petroleum has been the principal source of liquid fuels and lubricants since 1859 and is a convenient root of many [organic] chemicals in common use today. In recent years the difference has narrowed between the cost of producing liquid fuels from well petroleum and other sources. This narrowing of cost difference has resulted both from the increased cost of finding new sources of petroleum in the United States and the experimental demonstration of lowered costs for synthetic liquid fuels by the Federal Bureau of Mines and by industry. Available petroleum resources of this country are being reduced and eventually may be inadequate to meet the demand. Alternate means of assuring an adequate supply of liquid fuels for this country include the development of processes for utilizing other carbonaceous materials such as oil shale and coal.

Jan 1, 1960

By Arno C. Fieldner

In view of the widespread interest in the production of synthetic liquid fuels from solid and gaseous fuels to supplement declining reserves of petroleum, and the many requests that are now being received for information on the subject, this bibliography of Bureau of Mines contributions has been compiled. In addition to the publications issued by the Government in printed or mimeographed form, references are included to articles written by the Bureau staff for the technical press and to cooperative reports of work done jointly with States, colleges, and industries. References are given under each section in chronological order. Bureau of Mines bulletins, technical papers, and Minerals Yearbooks are printed and are obtainable at the prices indicated from the Superintendent of Documents, Government Printing Office, Washington 25, D. C. If no price is given, the publication is out of print. The price of entire volumes of the Minerals Yearbook or of reprints of certain chanters may be obtained upon request. Any orders or remittances in payment for these publications should be cent directly to the Superintendent of Documents and not

Jan 1, 1945

By J. E. Matta

The methane gas emitted from coal samples collected from the conveyor belts dumping into silos was measured by the Bureau of Mines. Approximately 50 pct of the total gas desorbed into a sealed can within 1 week was released during the first 24 hours. No simple correlation between the gassiness of the coal stored and the methane concentration in the silo open space above the coal was found. This was probably because the gassier coals were stored in open-top Silos, which were better ventilated. Although the methane concentration in the open space above the coal pile was less than 1 pct for all 34 silos investigated, a methane measurement in the coal pile showed that high methane concentrations can exist. The methane released in the pile appears to accumulate and not liberate freely into the open space above the coal pile. Probably this gas is released during reclaiming operations, but further research is required to substantiate this claim.

Jan 1, 1978

By Frank E. Williams

Nuclear detonation data were accumulated, studied, and evaluated by the Bureau of Mines to visualize how nuclear explosives might be used in a shale?-oil industry, The evaluation shows that the Green River Formation at the semi-isolated locale of Piceance Creek Basin, in northwestern Colorado; is thick and widespread enough to warrant consideration of nuclear mining in lieu of conventional methods, Because cost data for nuclear explosions are limited; cost comparisons are made largely by assumptions. Also described are the history of the shale-oil industry, the geology and size of oil-shale resources; and conventional mining methods and processing technology.

Jan 1, 1969

By B. W. Dunning

The Bureau of Mines investigated the concentration and distribution of precious metals in the various fractions produced from mechanical processing of obsolete military electronic scrap. Whole avionic units, printed circuit cards, and electrical connectors were processed and analyzed. Materials recovered included baghouse lights, wire bundles, mag-netics, and metal concentrates from eddy-current and high-tension sepa-ration. Higher value fractions were processed by a commercial toll refiner for recovery of gold and silver. Lower value fractions were analyzed by the Bureau. Three fractions, the lights, wire bundles, and metallics from high-tension separation, contained most of the precious metals. Depending on the type of scrap feed, these fractions represented 34 to 60 pct of the original sample weight. Collectively, they represented 68 to 97 pct and 75 to 98 pct of the contained gold and silver, respectively.

Jan 1, 1983

By W. D. Mcmillan

During the fall of 1943 the Bureau of Mines put down four churn-drill holes totaling 435 feet of bore at the McGregor zinc lead mine near Potosi, Washington County, Mo., after the property had been examined by John Soule, an engineer of the Bureau, in the fall of 1942. A small production of lead and barite ore had been maintained at this property for many Years from shallow deposits in residual clays. A few shafts had penetrated the underlying dolomites and exposed a network of narrow fractures containing galena, sphalerite, barite, and marcasite. The drilling by the Bureau tested conditions at depths ranging from 80 to 130 feet. This report sets forth the data resulting from the work.

Jan 1, 1948

By W. K. Sawyer

Resistivity, porosity, permeability, and saturation data were obtained on core samples from the Big Injun, Clinton, Gordon, Bradford Second and Third, and Venango Second oil sands and formation factor-porosity relationships were derived using the general form of Archie's equation F = aø-m, where F is the formation factor, ø is the porosity, and a and m are constants that depend on characteristics of the rock. It was found that a and m varied significantly between sands, as did the exponent in the Archie relation I = Sw-n, where I is the resistivity index and S, is the water saturation. The average exponent, n, determined from all data was 50 percent greater at residual oil saturation than at residual water saturation. Samples from each sand exhibited differences in directional resistivity and/or permeability. The Bradford Third sand data showed correlation between resistivity and permeability anisotropy.

Jan 1, 1971

By I. L. Nichols, K. C. Dean, P. H. Johnson

Hydrochloric acid , sulfuric acid , and chloridizing roast- water leaching methods for dissolution of cesium and rubidium from Maine , Canada , and Southern Rhodesia pollucite ores and their flotation products were investigated by small- scale tests . Optimum conditions were determined to be ( 1 ) for hydrochloric acid leaching , use 12.7 equivalents of 8.8 normal acid per equivalent of cesium in the sample and leach for 6 hours at 100 ° C ; ( 2 ) for sulfuric acid leaching , use 12.7 equivalents of 14.4 normal acid and leach for 2 hours at 120° C ; and (3 ) for chloridizing roast - water leaching , roast minus 200 - mesh ore, limestone , and calcium chloride in a ratio of 2 : 4 : 1 , respectively , for 1 hour at 900 ° C , and leach the calcine for 1 hour at 80 ° C with enough water to give 35 pct solids . Extractions of cesium from ores and flotation products containing over 20 pct cesium were in excess of 97 , 93 , and 96 pct for the hydrochloric acid , sulfuric acid , and chloridizing roast - water leach processes , respectively .

Jan 1, 1964

By E. L. Garton

The oil-producing district, "Southern Oklahoma," is generally considered to be that part of the: State lying southwest of the Arbuckle Mountains. It includes six counties: Cater, Cotton, Garvin, Jefferson, Kiowa, and Stephens. At present cost of the oil is produced from formations of Pennsylvanian age. The individual crude oils resemble those produced in other parts of the State, except that the sulfur content is rather high. This report is a continuation of a study of Oklahoma crude oils3/being made, by the Bureau of Mines, Petroleum Experiment Station, Bartlesville, Okla. in cooperation with the State of Oklahoma. Analyses are given of 27 samples obtained from 21 fields in the southern part of the State, end the physical and chemical characteristics of these crude oils are discussed briefly. Analyses of crude oils from other Oklahoma areas and publications in which these analyses may be found are listed in tables 2 and 3.

Jan 1, 1941

By Maurice Deul

A special short-term research project was initiated to develop plant design parameters for treating mine waters to yield an effluent acceptable for discharge into streams and a sludge amenable to effective and economic disposal. Neutralization was investigated to provide simple and direct treatment of ferruginous acid waters using lime; coarse limestone, and limestone followed by lime. Limestone treatment was accomplished using a small cement mixer as a simple reactor to provide abrasive agitation of limestone and mine water. Results from tests with nine mine waters encompassing a wide range of iron and acid concentrations showed that coarse limestone, one of the cheapest neutralizing agents known, is potentially useful for treating mine water discharges. However, process variables must be defined more completely before the practical applications and limitations of the process can be fully established. In all the tests a pH of >7.2 was obtained ultimately with limestone. Reaction time to reduce the iron content below 7 ppm in the water was dependent on the original ferrous iron concentration. For waters with high ferrous iron content, treatment with limestone followed by lime rapidly produced an acceptable treated water, Sludges with good settling and handling characteristics resulted when limestone was used for neutralization either alone or with subsequent treatment. Reaction rates are expressed graphically as pH change and iron depletion curves; characteristic solids settling curves are shown. The temperature dependency of ferrous iron oxidation was verified.

Jan 1, 1967

By J. J. Hoeppner

Lignite samples were collected so as to be widely representative of the extensive deposits in the western north-central area. These were carbonized at temperatures ranging from 450° to 550° C., according, to a standardized procedure. In general, product yields varied; extremes obtained on selected samples show char recoveries on the moisture- and ash-free basis as 56.7 percent for slack lignite or "leonardite" to 80.8 percent for a concentrate of the fusain component from a typical face sample; normal lignite samples averaged approximately 70 percent. Tar-plus-light-oil yields ranged from 3.3 percent for the fusain concentrate to 11.0 percent for a normal sample, averaging approximately 8 percent; gas recoveries varied more widely both in yield and in composition, ranging, from 10.0 percent to 27.7 percent, the latter being from leonardite and quite high in carbon dioxide. Sampling was conducted with the view of representing, as nearly as possible, all beds delineated by Brant (2);4/ many are necessarily missing since collection was confined largely to worked deposits. Data presented in this report indicate a general uniformity of North-Central lignite in respect to low-temperature carbonization, with a few possible exceptions of a local nature. When processed according to the indicated conditions, maximum tar yield may be realized with minimum loss of recoverable heating value of the original coal. Natural weathering of lignite, however, does affect tar yield adversely and should be held to a practical minimum in any commercial operation.

Jan 1, 1956

By William T. Boyd

Foreign mining publications describing successful hydraulic mining installations, and successful domestic hydraulic mining in a gilsonite bed, have prompted the Federal Bureau of Mines to conduct a literature survey of foreign publications to determine if the hydraulic mining method can be applied to domestic coal mining. Most foreign publications do not give detailed data about the water pressures, water capacities, and production and manpower requirements for successful hydraulic mining, However, they do provide enough general data on mining conditions, manpower, and equipment used to show that conditions in many bituminous coal deposits in the United States may be favorable for economical coal extraction, using high-pressure water jets. Therefore, the Bureau proposes to conduct a field investigation to determine the most appropriate natural conditions, water pressures, and equipment for successful hydraulic mining of coal beds in the United States with variable dip, thickness, and hardness. In the past, technical personnel reviewing foreign mining reports assumed that a steeply pitching coal bed was necessary for successful hydraulic mining. Although the structure of the coal bed may be a factor in gaining assistance from overburden pressures or help in an integrated hydraulic mining and transportation system, the coal is broken mainly by the action of high-pressure, water-penetrating cracks, fissures, or cleats; therefore, the slope of the coal bed is not necessarily a determining factor in hydraulic mining.

Jan 1, 1959