Search Documents

By E. L. Singleton

The electrochemical reduction of aluminum chloride to aluminum was investigated in a closed, two-compartment cell utilizing a molten chloride electrolyte. The externally heated cell was divided into a reduction compartment and a combination AICl3 feed and metal removal compartment. Aluminum was deposited at 700° C on a molten aluminum catbode from a KCI-NaCI-AICI3 electrolyte. The AICl3 content of the electrolyte was replenished by either vapor or solid additions. The chlorine evolved was collected and measured to give a quantitative evaluation of AICl3 reduction. The effects of anode and cathode current densities and AIC13 concentration on anode current efficiencies were studiedo A range of 64 to 84 percent anode current efficiency was obtained with the 25-pound electrolyte capacity cell and related auxiliary equipment.

Jan 1, 1968

By Elaine T. Bowers

The Sunnyside single-entry project pioneered the use of single entries for longwall development in this country. During the 10-year course of the project, an immense amount of information was gathered. Over three miles of entries were observed primarily through instrument groupings placed in strategically located areas or "rooms." Nearly 1,200 instruments were monitored to gain information on the behavior of coal entries during development stages and through the mining of two longwall panels. This was one of the most extensively documented projects undertaken by the Bureau, The data gathered has a great potential for scientific research especially in the area of longwall mining. This Bureau of Mines report presents the ground control data gathered, in the form of computerized plots. Roof-to-floor deformation and load on cribs and roof bolts make up the bulk of the data, which is presented as load or deformation versus time. The plots are organized, generally, by the three main entries involved and, specifically, by the individual areas or rooms in those entries. No major attempt will be made, in this paper, to analyze the data other than to identify its source arid its history.

Jan 1, 1983

By Thomas M. Barczak

The U.S. Bureau of Mines has been conducting research to optimize the design and utilization of mine roof support systems. An objective of these efforts is to evaluate the mechanical and structural responses of various mine roof support systems under simulated load conditions in the Bureau's mine roof simulator. Underground studies are also made to evaluate the in situ behavior of support structures. The purpose of this report is to document practical applications for longwall face and gate road supports that have resulted from these studies. This report is not intended to be an all-inclusive manual on every aspect of support utilization, but it does provide a comprehensive assessment of practical considerations relating to the mechanical and structural behavior of these support systems. Forty-six recommendations are made to provide assistance to mine operators in the testing, selection, and utilization of longwall face and gate road supports. Many of these recommendations offer innovative solutions to everyday problems faced by mining personnel in the control of ground in longwall mining.

Jan 1, 1989

By K. E. Tame

The Bureau of Mines is studying possible modifications in conventional uranium ore-processing steps to confine and permit controlled disposal of radioactive wastes. A potential method of minimizing pollution from radio-active nuclides, principally radium 226, in uranium mill waste streams is to reuse the waste solutions within the mill. Such reuse of waste solution in the Kerr-McGee Shiprock-type process was investigated in the laboratory. The Shiprock mill employs a two-stage acid-leaching process for dissolution of the uranium, countercurrent decantation for liquid-solid separation and washing, and organophosphorus solvent extraction for recovery of the uranium and vanadium from solution. The simulated use of barren raffinate instead of fresh water in the mill circuit was carried through a laboratory campaign of 28 interlocked leaching, washing, and solvent extraction cycles. About 99 percent of the uranium and 91 percent of the vanadium were dissolved from the are, Washing efficiency in the thickener circuit averaged about 99.5 percent when the pulp was washed with enough barren raffinate and makeup water to recover 2.5 tons of pregnant solution per ton of ore. The only solution discarded was that contained in the washed and thickened leach residue. A buildup of salts due to recycling of solutions did not adversely affect operation of the washing circuit.

Jan 1, 1962

By C. D. Messelt

The Bureau of Mines investigated the application of a diffusion model to sintering rate data developed for lithium titanium ferrite. The data were obtained by sintering pressed pellets under identical conditions for various times up to 11 hours. Stereological measurements were made on polished sections, and sintering rates were calculated. A model for intermediate stage sintering was fitted to the stereological data. This procedure produced a method by which these type data could be used to study the relative importance of volume and grain-boundary diffusion under a variety of sintering conditions.

Jan 1, 1979

By S. D. Hill

To help insure the continued viability of the minerals and materials sector of the U.S. economy, the Bureau of Mines is conducting research and disseminating technology that will result in more efficient minerals extraction. As part of this effort, a process is being investigated that involves an aqueous chlorine-oxygen leaching procedure to treat complex sulfide concentrates to produce ZnCl2. Subsequent fused-salt electrolysis of the ZnCI2 produces high-purity zinc metal. Previous reports described preliminary, small-scale research on the chlorine-oxygen leaching system and fused-salt electrolysis of ZnCl2. This report discusses the details of design, construction, and longterm, continuous operation of both monopolar and bipolar fused-salt cells. The effects of temperature, electrode gap, current density, electrolyte composition, and electrode configuration on current efficiency and energy consumption were determined for a ZnCl2-KC1-NaCl electrolyte system. Zinc metal was produced at the rate of about 50 lb/day in a monopolar cell which was operated continuously for 60 days with current efficiencies from 85.8 to 98.6 pct and an average power consumption of 2.1 kwhr/lb. Bipolar cells with several different electrode configurations were operated for 90 days. A current efficiency of about 70 pct and power consumption of about 1.7 kwhr/lb of zinc were achieved using a three-electrode-pair, bipolar assembly with a chlorine gas lift pump to circulate electrolyte.

Jan 1, 1981

By James P. McGee

Use of nuclear reactors to furnish high-temperature heat is a field that has not received as much attention as propulsion and electric power production. Investigations are being conducted under a joint Atomic Energy Commission (AEC)--Bureau of Mines research program to determine the feasibility of using nuclear heat for chemical processing. A part of this process-heat-reactor program is the study of a system in [hich] helium transfers heat from 8 nuclear reactor to a chemical processing [essel]. This requires construction of (1) a nuclear reactor to operate with helium exit temperature of 2,500° F. and with pressures in the range of 250 to 500 p.s.i.g. and (2) a processing vessel (heat exchanger) to convert the enthalpy of the helium into chemical process reaction heat. Neither component exists at present, and development of each promises to be a formidable task. To aid in the study of such a system, the Bureau of Mines has designed and constructed a vessel heated by electrical induction to simulate a source of nuclear fission heat. This vessel is undergoing preliminary testing. Gasification of coal and reforming of hydrocarbons are promising uses for nuclear heat. It appears that a higher price per unit of nuclear heat can be tolerated for chemical processing than that allowable for power generation.

Jan 1, 1960

By Alex C. Smith, Michael J. Sapko

A series of explosive detonation experiments was conducted in NIOSH’s Bruceton and Lake Lynn Experimental Mines to evaluate low level (<6 psig) detonation wave propagation behavior in single and multiple entry configurations. Entry cross-sectional area varied from 5 to140 m2 and explosive weights of Pentolite ranged from 0.24 to 2.4 kg. Behavior of the detonation wave was evaluated through recording of the pressure as a function of time and distance from the explosive detonation in single and multiple entry interconnecting tunnels. Peak pressure from detonation of an explosive in an underground mine maintains magnitude for a greater distance than is the case on the surface and is shown to follow the simple scaling rela-tionship P = 702.8(W/Vt)0.514(0.65)n, where P is the peak detonation pressure in kPa, W is the weight of the explosive charge in kg, Vt is the total volume in m3, and n is the number of splits, n = 0, 1, 2, …n. The total energy, or impulse, I, generated by these detonations can be expressed as I = 1.34(W/A)0.64n, where W is the weight of the explosive charge in kg, A is the area of the main tunnel in m2, and n is the number of side en-tries, n = 0, 1, 2, …n.

By C. E. Brechtel

A testing program was conducted to design a cemented backfill fur hydraulic placement in underhand cut and fill mining of a steeply dipping coal seam. The testing evaluated the use of three different backfill aggregates, locally available at the coal mine, with Portland cement and five different pozzolans, including a Class F fly ash, a Class C fly ash, a cement kiln dust and ground smelter slag. Both viscosity and uniaxial compressive strength of backfill mixtures with different pozzolan and Portland cement contents were used to evaluate their suitability. Based upon the results of preliminary testing, an optimum mixture of alluvial sand with six percent Portland cement and ten percent Class F pozzolan was chosen for further compression testing.

Jan 1, 1985

By R. L. Mazza

This final report on methods of reducing and controlling methane in coal mine gob areas indicates that vertical degas holes are beneficial to the mines of northern West Virginia working the Pittsburgh Coal. The USBM funded project involved the drilling and testing of eight vertical holes (four over longwall panels and four over room and pillar panels) based on a review of 13 previously in existence. Areas of observation included gas production history, flow entry profile, underground methane reductions, strata separations, and casing loads (accompanying subsidence). Observations led to the drilling of successful holes drilled short of the mine. Eleven gas production response to applied vacuum tests were conducted at nine degas holes under the contract. Significant production responses were recorded over longwall gobs.

Jan 1, 1977

By John P. Powell, J. L. Eakin

"INTRODUCTION AND SUMMARYNowata County, in the northeast corner of Oklahoma, is one of the principal oil-producing counties of this stripper area. Many fields in the county were opened and much oil was produced before statehood. The location of the major fields, as defined by the Oklahoma Corporation Commission, 2/ the outline of the areas of water-flooding activity, and the location of the several projects described in detail in this report are shown in figure 1.There was some drilling in the county earlier; but it was not until after 1904, when the Secretary of the Interior confirmed as valid the leases granted by the Cherokee Nation, that the major drilling activity began. Initial development in this part of Oklahoma was in the Chelsea field in Rogers County, which adjoins Novata County on the south. The activity spread rapidly northward to the Alluwe and Coody's Bluff fields, and then to the Nowata-Claggett field. Continued exploration resulted in discovery of the Delaware-Childers field, where some wells having an initial production of 1,000 barrels daily were completed. Fields discovered and developed during the next few years included the Lenepah (Elliott), Adair, California Creek, Curl Creek, Woody, and South Coffeyville. The oil-production history of Nowata County is shown in figure 2. In assembling the data for a production curve, it was found that the combined production records for Nowata and Rogers Counties were available for 1914 to 1951, inclusive, and that records for the individual counties were available only from 1926 to 1951, inclusive. The early production figures for the counties from 1905 to 1914, inclusive, except for 1909, were calculated from the initial production statistics of the Federal Geological Survey mineral resources bulletins and production data assembled by C. H. Beal. 3/ The production values for 1905 to 1926 for Nowata County were obtained by dividing the total production for the two counties by a percentage factor derived from known facts regarding the oil industry in the area. Production figures for the individual counties from 1926 to 1933, inclusive, were obtained from the files of the Oil and Gas Journal, and the figures from 1933 through 1951 were obtained from monthly reports of the Oklahoma Corporation Commission."

Jun 1, 1952

By Robert C. Bates

This Bureau of Mines report converts published data on the cost of ventilating uranium mines to a common price base and analyzes these data to determine the cost per ton of uranium ore at various levels of radiation exposure control. There appears to be an exponential increase of cost as the radiation level is lowered. The 1967 base costs are extrapolated to present dollars, and some cost comparisons are given for other radiation control measures.

Jan 1, 1981

By WM. H. RINKENBACH, C. A. Taylor

No complete work on explosives, their constitution and analysis, has hitherto been published. Several books that contain chapte.r;s on analysis do not cover the matter thoroughly. Methods tha;t, manu~ facturers, testing stations, and other . agencies have developed to meet their own requirements have not been made public. The Bureau of Mines has issued four publications 1 - cov:eri:ng special phases of the subject. This bulletin. is not inte.nded to replace those reports, but rather to cover present methods employed 'in the , industry and to include all classes of explosives and the materials used in their manufacture. No sharp distinctions can be drawn between classes of explosives. . Surplus military explosives, for example, may be used for blasting, just as blasting explosives, under some conditions, may be employed for military purposes. Moreover, one class gradually merges into another because of similarity in composition. Explosives are here grouped as dynamites, black powders, propellants, detonators, and primers. Some materials are used in practically all these groups ; others in only one. To discuss all the materials that have been or that may be used and the methods for their identification and quantitative determination is not feasible, but the methods described will probably suggest ways of examining new mixtures.

Jan 1, 1923

By J. V. Batty

Radioisotopes of selenium (se78) and tellurium (Te123) were successfully employed by the Bureau of Mines as tracers in metallurgical research directed to developing improved methods for volatilizing these elements from low-tenor raw materials. Prior research, guided and controlled by conventional analytical methods, was seriously hampered by inconsistent selenium and tellurium analyses, by the slowness of the conventional chemical methods, and by the poor accountability of these volatile elements in test products. Methods were devised and evaluated for admixing the radioactive tracer with typical raw materials and then following the deportment of the selenium and tellurium by radiometric methods with occasional chemical analysis checks. These techniques were found unusually effective in (1) quantifying the completeness and the rate of volatilization of selenium and tellurium while heating the raw materials at different rates to different temperatures and (2) accurately tracing and quantifying the distribution of minute amounts of these volatile elements in the several products made by high-temperature treatment and in the several units comprising the experimental equipment.

Jan 1, 1962

By John G. Parker

Important quantities of gold, silver, platinum-group metals, selenium, tellurium, and arsenic are recovered in the processing of copper concentrates. The objective of this Bureau of Mines study was to determine the occurrence of these elements in copper ores and to trace their distribution during subsequent processing steps. The study describes the important areas supplying concentrates, precipitates, and unrefined copper to the copper smelting and refining industry in a composite of the years 1971-74. The relative importance of these areas as a source of the respective byproducts is assessed. The lack of certain quantitative and assay data, recycling of dusts and slags, and the addition of scrap to the feed often complicates calculations and estimations of the byproducts in the smelter-refinery throughputs. Such volatile or low-boiling point elements as arsenic, selenium, and tellurium may be lost in gaseous and other emissions in various processing stages, or they may be concentrated in slags and residues for which samples were not available. The effects of antipollution legislation to improve control of sulfurous and other emissions that may affect recovery of certain byproducts was noted. A section on newer technology illustrating hydro-metallurgical techniques that may affect the recovery of minor metals is included.

Jan 1, 1978

By Leonard Obert

Part I of this report3/ proposed a sonic method for determining pressure, in situ, on rock pillar, arches, and other structures. The method required (1) a laboratory determination of the variation of the velocity of sound with pressure in samples of rock taken from mine pillars to establish a velocity pressure relationship for the type of rock, and (2) a measurement of the velocity of sound in the mine pillars from which the laboratory samples were taken. The pressure on the pillars could be determined by correlating the velocity in the pillar with the velocity-pressure relationship established in the laboratory. The success of this method depends on the extent to which velocity of sound varies with pressure. Furthermore, Young&apos;s modulus of elasticity, E, can be calculated from longitudinal velocity, V, by the relationship, E = V2d ...(1) where d = density. Hence, the variation of the elastic modulus with pressure also can be determined. It pointed out that this method might be extended to assist in the prediction of rock bursts, inasmuch as the rock is subjected to extreme pressure in these instances.

Jan 1, 1940

USBM Contract H0133045 consists of the design, build and test of 50 waveform generators. The waveform generator is a small ULF transmitter operating in the 1 to 3 KHz frequency range for the purpose of locating trapped miners during a mine disaster. This contract provided for the design, test, and building of 50 waveform generators using a discrete component construction with an option of using hybrid construction techniques within 105 days after the effective date of the contract. Because of large quantity economic considerations, this option was not initiated. Two engineering models were designed, constructed and tested and 50 final production units were fabricated using discrete construction. Complete documentation is supplied under a separate package which includes final schematics, parts list, layout information, equipment specification, production test procedures and qualification test procedures. Ten units have been delivered to the USBM. The remaining 40 units are being retained for packaging under contract H0242010 Transmitter Package and Receivers.

Jan 1, 1974

By J. E. Crawshaw

"The few previous observations of the effect of turbulence on limits of inflammability have been made on a small scale in turbulence produced either by a fan or by movement of the mixture.By a suitable amount of turbulence from a fan the lower limit of methane was 5 per cent as compared with 5 per cent observed for quiescent mixtures in the same vessel.3 With a streaming movement of the gas mixture within the range of speed from 35 to 65 centimeters per second (69 to 128 feet a minute) the lower limit was approximately 5 percent,4 For a quiescent mixture of ethane the lower limit was 3.10 per cent ethane, but with fan running at a moderate speed a 3 per cent mixture exploded.5The object of the tests herein reported was (1) to determine the lower limit of natural gas in a mixture of natural gas and air Which would be ignited and propagate violently when the turbulence was produced by explosives fired from a cannon into the mixture; (2) to observe the behavior when the mixture contained less than this low limit; and (3) to determine how turbulence produced by a fan affects thin limit.Four series of tests were run, three of which were to determine the effect of different sources of ignition: Tests with (1) an electric igniter; (2) 3F black blasting powder stemmed with 2 pounds of dry fire clay stemming used to ignite the mixture, and (3) 40 per cent straight nitroglycerin dynamite unstemmed. The fourth was made to study the effect of turbulence produced by a two-speed electric fan, using an electric igniter as the source of ignition.In both series of tests with explosives, charges of 50 and 200 were used to determine the effect of increased quantity of explosives on the lower limit of natural gas."

Jul 1, 1930

By E. C. Tarpley

An acid-extraction procedure developed in Germany for determining mineral matter in coal was investigated by the Bureau of Mines to determine its application to American coals. It was found to be suitable for all ranks of coal from anthracite to lignite if modified slightly for coals containing considerable quantities of calcium compounds, such as calcite or calcium humate. The precision of the method is satisfactory, and the results are probably closer to the true content of mineral matter than those obtained by empirical formulas. The method requires considerably more analytical data than the Parr or approximation formulas but is no more time consuming than obtaining the necessary data for the King, Maries, and Crossley formula (theoretically the most comprehensive empirical formula used). An appendix to this report includes a detailed description of a recommended procedure.

Jan 1, 1959

By R. J. Morrell

The Bureau of Mines conducted a series of laboratory experiments to test a cutting technique for hard rock using large-scale drag cutters. Cutting experiments were performed on rocks ranging in compressive strength from 10,000 to 27,000 Ib/in2, using large drag cutters from 3 to 6 in. in width. The tests were conducted on a special test apparatus, called a ripper tester, which made a curvilinear cut across the rock sample while measuring the cutting force acting on the drag cutter. The cutting method that evolved from these experiments is called ripper cutting, and its energy efficiency appears superior to all other large-scale mechanical fragmentation techniques. In addition, the method cre-ated very little dust, and the wear on the bits was negligible. A fragmentation system based on ripper cutting was then devised, and a large-scale test device was fabricated to allow full-scale laboratory testing of the system. The results of these tests will be published in future Bureau reports.

Jan 1, 1986