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By D. C. Fleck

Electrorefining yttrium from selected low-melting yttrium--base alloys is investigated, and various halide systems are studied as potential electrolytes for use in preparing low-oxygen yttrium by electrorefining unalloyed yttrium. Yttrium cathode products having significantly less metallic impurities than the anode materials were prepared from alloys containing nickel, iron, and manganese by electrorefining in LiCl-YC13 electrolytes at 900° to 1,000° C. Yttrium-copper and yttrium-magnesium alloys are not suitable as anode feed materials, An evaluation of chloride, fluoride, bromide, and mixed chloride-fluoride electrolytes showed that cathode products containing much less oxygen than the anode material can be obtained in the fluoride and mixed chloride-fluoride systems. Initial cathode current density has no apparent effect on the purity of the products obtained in both phases of the investigation.

Jan 1, 1973

By M. M. Fine

Chalcocite flotation concentrates (26-34 percent Cu and 6-7 percent S) were roasted in air to determine sulfur elimination as a function of temperature, airflow rate, and residence time. Fluosolids roasting was evaluated batchwise and continuously in a 4-inch fluid-bed reactor. Kiln roasting tests were carried out in a 4-inch ID by 6-inch-long rotary drum. Pelletizing the very fine concentrates prior to roasting was essential to minimize dust losses and accretions. Concentrate pellets, sized minus 10 plus 20 mesh and bonded with 2 percent bentonite, were excellent feed for fluosol¬ids roasting and limited dust losses to 10 percent or less. One-fourth-inch pellets were best suited to kiln roasting. Both techniques were capable of producing copper calcines analyzing well under 1 percent residual sulfur when operated at 900° C with average retention times of 3 to 4 hours. Calcined pellets were strong, porous, and readily reducible.

Jan 1, 1970

NIOSH research has focused on the monitoring and the control of methane levels in active mine workings. Response times for instrumentation using catalytic heat-of-combustion sensor technology were evaluated. NIOSH research has modelled the flow of methane gas onto long-wall faces and gobs, developed engineering controls to limit methane levels during mining, and designed coalbed and gob degasification systems. Available methane control systems have been challenged by recent developments in longwall and room-and-pillar mining systems. This includes increased face advance rates leading to increased productivities, increased longwall panel sizes, and the generally deeper workings of U.S. coal mines. The potentially violent nature of any underground explosion or ignition requires the measurement, control, and reduction of methane emissions into the mine environment for continued worker safety.

Jan 1, 2008

By G. R. Hopkins

According to reports received by the Bureau of Mines, Department of the Interior, as of January 1, 1934, there were 591 completed refineries in the United States, an increase of 86 ever the total reported at the beginning of 1933 and the largest total ever recorded. It should be noted that the 1934 total, although large, probably does not include more than half of the "pot-still" plants of 1 barrel to 50 barrels daily capacity which have sprung up within the last 2 or 3 years and about which very little information is available. However, the combined operations of these snail refineries are of negligible importance as altogether they refine less crude than one plant of average size. Of the completed plants, 454 were operating on January 1, 1934 and 137 were shut down. In addition, 13 refineries were under construction on January 1, 1934. Compared with the previous year these data indicate a marked increase in the number of operating plants, little change in the number of inoperative plants, but a decline in' the number being built. The material gain in the number of operating plants resulted primarily from the construction off approximately 25 refineries, averaging about 100 barrels capacity in the Kooky Mountain district, as well as from the addition of about 20 plants in the East Texas field.

Jan 1, 1934

By M. E. Poad, M. M. McDonald, J. C. Johnson, W. G. Pariseau

A U.S. Bureau of Mines case study of pillar recovery in high-grade ore near the Ross shaft at the Homestake Mine, Lead, SD, has demonstrated the usefulness of the finite-element method for evaluating shaft pillar mining plans and shaft stability. This report focuses on mine measurements and calibration of the two-dimensional computer model and is the second in a series of three Reports of Investigations describing the Ross shaft study. In this study, borehole extensometers and other instruments were installed to provide data for model verification and to monitor the shaft. Results of the recalibrated two-dimensional model (UTAH2) confirmed the premining stability evaluation. However, after mining began, concern was expressed because cracks and other signs of ground motion appeared at considerable distances from the area of active pillar mining. In part 3 of the study, an intense three-dimensional modeling effort using UTAH3 was initiated. The results again showed that the observed effects were within expectations and that the shaft would remain safe. Three-dimensional analyses of alternative pillar mining scenarios indicated that more of the shaft pillar ore reserve could be recovered than previously thought.

Jan 1, 1995

By Thomas J. Albin

U.S. Bureau of Mines research has found that maintenance of surface mining equipment is involved in slightly more than one-third (34.1 pct) of all surface mining accidents. Two groups of machines, haulage trucks and power shovels, accounted for over one-half of all surface mining mobile equipment maintenance accidents in 1978-84. Maintenance work-time histories for these machines were compared with accident records to identify the most hazardous-to-maintain systems within the machines. Recommendations to reduce the accident risk associated with maintenance of these hazardous systems are presented.

Jan 1, 1990

By E. R. Maize

This report is the second of a series on roof movement in coal mines. The first (R. I. 3355)4/ dealt with convergence of roof and floor and movement of the surface accompanying and following extraction in a mechanized mine in which retreat of rib lines was rapid. The studies reported herein were made in a mine in which all the coal is loaded by hand, and movement of the rib lines was much slower in consequence. In choosing a site for this work, it was decided that the mine selected should have natural conditions akin to those of the first study and entirely different methods of working. To this end a cooperative agreement was made with the Crucible Fuel Co. through W. J. Whitaker, secretary, for conducting the work in the company's Crucible mine, operating in the Pittsburgh bed in Greene County, Pa. This paper gives an account of the methods used in the investigation, excerpts from the data obtained, and such generalizations as can be made.

Jan 1, 1939

By E. R. Maize

This report is t e second of s series on roof movement in coal mines. The first (R. I. 3355)4/ dealt with convergence of roof and floor and movement of the surface accompanying and following extraction in a mechanized mine in which retreat of rib lines was rapid. The studies reported herein were made in a mine in which all the coal is loaded by hand, and movement of the rib lines was much slower in consequence. In choosing a site for this work, it was decided that the mine selected should have natural conditions akin to those of the first study and entirely different methods of working. To this end a cooperative agreement was made with the Crucible Fuel Co. through W. J. Whitaker, secretary, for conducting the work in the company?s Crucible mine, operating in the Pittsburgh bed in Greene County, Pa, This paper gives an account of the methods used in the investigation, excerpts from the data obtained, and such generalizations as can be made.

Jan 1, 1939

By Gergely Markos

Uranium mill tailings represent a potential threat to the human habitat by containing large amounts of radioactive and chemically toxic substances in high concentrations. These: undesired components enter the human habitat in various pathways such as by erosion and water or air transport. The main objective of this investigation was to evaluate the actual movement and model the potential movement of contaminants by seepage of water from the tailings into the subtailings soil. This report represents various models of the movement of contaminants using both theoretical approaches and empirical evaluation of data available from other investigations. The data consist of field measurements and laboratory determi¬nations of major and trace cations, the dominant anions, pH, and Eh of moist solids, extracts, and waters from the tailings and surroundings. Evaluation and interpre¬tation of data were accomplished by using Eh-pH diagrams, various statistical methods and the WATEQFC computer program. Data analyses show that the critical area of investigating movement- is the interfaces between tailings and the external environment. The chemical differences at interfaces seem to result in a sink system for contaminants. The tailings-soil¬-water system shows extreme complexities because of chemical and physical hetero¬geneity of the system preventing the use of a single comprehensive model to represent real conditions. The validity of the simplifying assumption used has been shown and increasing complexity has been built into the models. Analogs of these models can be used for evaluation of similar systems.

Jan 1, 1981

By H. S. Price

This report discusses the development of a mathematical model that describes the flow of methane only and methane and water in a coal bed during mining operations. Because of the complex geometry, boundary conditions and fluid properties, the model is based on a numerical solution to the equations describing flow. The goals for the development of this model and requirements to which it complies are for the most part expressly stated in Request for Proposal No. 50110752. In addition to the capabilities specified under the scope of work the model can handle an anisotropic porous medium and a source term has been added which will simulate, somewhat, the effects of desorption. This term will be pressure dependent. The effect of time on such a term is only taken care of in the change of pressure with time. This source term will have the dimensions of Mcf/day/Mcf pore volume. It will be a part of the input data to be supplied by the user and will be entered as a table of rates versus pressure. These models consider the fracture system as the main porosity. All computed results pertain to the fractures. The source term mentioned above represents the flow from the matrix porosity into the fracture. Such flow should be small compared with the flow between fractures since these models handle only one porosity structure system.

Jan 1, 2012

By John D. Bardill

Data from extensive tests was obtained on friction-head losses of various sand slurries, composed of materials of different specific gravities and under varying transport conditions, to provide useful information for designing hydraulic transport systems. The tests were run in a pilot plant through 2-, 3-, and 4-inch lines with slurries composed of relatively pure barite and limestone solids. Available grinding and classification equipment did not permit attaining a comparable size distribution in the two materials tested, thus preventing direct correlation of friction-head loss values to physical properties or mineral composition. A total of 495 measurements were made of limestone slurries in the 2-, 3-, and 4-inch pipe test sections at flow velocities from 6 to 14 feet per second and pulp densities from 40 to 70 percent solids. A total of 640 measurements of barite slurries were made in the 3-and 4-inch pipe test sections at flow velocities between 7 and 14 f.p.s. and pulp densities ranging from 40 to 80 percent solids.

Jan 1, 1962

By William J. Campbell

Three types of X-ray analytical instrumentation were compared for applications in the secondary brass and bronze industry. The instruments were a conventional X-ray spectrograph, a portable X-ray spectrograph, and a radioiso-topic X-ray analyzer using balanced filters. The following two general applications were considered: Rapid identification for sorting scrap metals and quantitative analyses to provide guidance in the melting and casting of alloys. Twenty-three analyzed copper-base alloys were used as standards. Although the alloys varied widely in composition, matrix correction procedures were not necessary except for copper. The conventional X-ray spectrograph provides positive identification of the alloys and quantitative values for the six elements investigated--aluminum, copper, iron, lead, tin, and zinc. Equivalent results were obtained with the portable X-ray spectrograph for those elements whose characteristic X-rays are in the wavelength range of the instrument. The radioisotopic X-ray analyzer distinguishes certain groups of alloys and provides quantitative determinations for copper, lead, tin, and zinc. The sensitivity of the analyzer was marginal for the determination of small concentrations of elements of atomic number 26 or lower.

Jan 1, 1972

By Kenneth B. Higbie

METALLURGICAL ACTIVITY in 1963 was again dominated by the insatiate demands of research and development conducted in conjunction with the nation's defense and aerospace programs. An increasing effort was noticeable throughout the year, however, to apply to the commercial field many of the processes and techniques that have been developed by government-sponsored research. Particularly effective has been the Industrial Applications Program of the National Aeronautic and Space Agency through which many of the technological advancements made during the course of NASA research and development have been published and released to the public. POWDER TECHNOLOGY Powder metallurgy techniques for fabricating metals, not long ago declared outmoded because of improved casting and shaping methods, have since made an astonishing comeback. Traditionally mechanical pressing of powder shapes has been employed when melting and casting was difficult or impossible, when phase relationships needed to be sidestepped, or when machining costs could be avoided. Hence, it has long been used for producing relatively small special shapes of high-melting metals and alloys. Small iron parts produced with a punch and die have been common for many years, but powder metallurgy techniques are now applicable to a wide range of materials and items. Hard-to-handle materials including refractory metals and their alloys are now rolled, forged, or extruded from billets made by sintering isostatically compacted powders. The major element of the powder metallurgy industry still comprises iron shapes, however, and two-thirds of the annual 100,000 tons of powder metallurgy products are made of iron. The largest single user of powder-forming techniques is the automobile industry which currently consumes 14,000 to 16,000 tons of iron powder per year. A typical 1963 model auto contained more than 100 pressed powder parts (e.g., transmission gears, timing gears, sprockets, ball joint suspensions) totaling 5 to 7 pounds per car. Some of these powders are used in self-lubricating parts of porous copper and copper alloys containing as much as 20 volume-percent lubricating oil. The expanded use of powder techniques, coupled with

Jan 1, 1964

By Michael Schmitz, Eugene Ahrenholtz, William A. Heitbrink, Jeanne A. Zimmer, Andrew B. Cecala, Ernest S. Moyer, Earle H. Andrews, Chris C. Coppock, John A. Organiscak

Many different types of surface mining equipment use enclosed cabs to protect equipment operators from health and safety hazards. The overburden removal and mining process can be extremely dusty and can cause excessive dust exposure. To study this issue, a cooperative research effort was established between the National Institute for Occupational Safety and Health, U.S. Silica Co., Clean Air Filter Co., and Red Dot Corp. in an effort to lower respirable dust levels in an enclosed cab on an older surface drill at a silica sand operation. Throughout this research effort, a number of modifications were incorporated into the drill's filtration and pressurization system, as well as in other areas, to improve its design and performance. An average cab efficiency of 93.4% was determined with gravimetric sampling instruments when comparing the outside with the inside cab dust levels on the final design. Although this study considered just one operation, the goal was to identify cost-effective improvements that could be implemented on all types of enclosed cabs to lower respirable dust concentrations. Two critical components for an effective enclosed cab system are having a properly designed, installed, and maintained filtration and pressurization system, along with a method for maintaining structural cab integrity, which allows the cab to be positively pressurized. Another important component is maintaining cab cleanliness. Although this research was originally directed toward the mining industry, it is also applicable to agricultural or construction equipment.

By V. R. Spironello

The Bureau of Mines is involved in research directed toward the utilization of municipal solid waste. One of the primary objectives is the recycling of the magnetic fraction of municipal solid waste (raw refuse). This is consistent with one of the Bureau's goals, which is to minimize the requirements for mineral commodities by maximizing metals recovery from secondary domestic resources, In this investigation, cupola trials were made using combinations of refuse scrap with shredded automobile scrap under basic and acid slag practices. Furnace operating information and the behavior of alloying and tramp elements was obtained. The research showed that it is possible to utilize up to 60 percent refuse scrap in the cupola under basic practice and 30 percent under acid practice, Aluminum in refuse scrap, present in bimetallic cans, increased the recoveries of silicon and manganese charged to the cupola. Increased use of refuse scrap provided iron of lower sulfur. The alumina resulting from oxidation increased the slag volume. The aluminum and tin contents of the iron increased with increasing levels of refuse scrap in the charge. Lead was not a problem with respect to contamination of the iron. In basic practice, operation of the cupola was satisfactory since all slags were adequately fluid. In acid practice, operation became troublesome above the 45-percent level. Under both practices, the cupola iron melting rate decreased. Particulates in scrubber water and stack condensate samples contained lead, zinc, and tin, and the dust load increased. The tensile and transverse strengths of the iron produced under both practices are reported.

Jan 1, 1980

By W. W. Adams

Increased employment and a lower accident-frequency rate were the outstanding features of the metal- and nonmetal-mining4 industries of the United States in 1939 compared with 1933, according to reports furnished by individual mining companies to the Bureau of Vines, United States Department of the Interior. Except for 1937, the reports for 1939 showed gains both in number of employees and number of mar -hours worked over all years since 1929. The accident-frequency rate per million man-hours of exposure to mining hazards was lower than in any year since 1925. Reports for 1939 revealed a total of 111,909 men employed in and about mines, an increase of inure than 8 percent over 1931 The total volume of labor performed at all mires was slightly more than 299 million plan-hours, an increase of mare than 10 percent over 1938. As these gains suggest, the average employee had a longer period of work in 1939, the increase amounting to r workdays per employee.

Jan 1, 1941

By Ronald J. Mathis

The objective of this contract is to design, build, surface test, and evaluate a breadboard prototype of the Variable Wall Mining System so that data are available for the design of a production machine. The Variable Wall Mining System (VWMS) consists of a series of side cutting augers, connected end to end, and distributed across a panel. Supplying rotary power at the end of the string and anchorage from conventional longwall roof supports, the augers are sequentially thrust into the face and then lifted to the roof to extract the coal in a continuous manner. The augers not only cut but also transport the coal. The effort described in this report summarizes the operation characteristics of the VWMS, the design methodology used to develop various working models, the surface testing of a ½ -scale version of the VWMS, prediction of power requirements and performance potential of a full-scale system, and a critique of the VWMS concept, conclusions, and recommendations.

Jan 1, 1987

By Harold J. Miller

Loading and haulage of run-of-mine ore is frequently the highest cost in underground mining operations. These costs can be significantly reduced by use of belt conveyors, a common practice in coal and similar soft miner ii mines. This is particularly true if oversize ore and rock can he eliminated prior to conveying; thus producing a demand for crushers near the production areas. Portable feeder-breakers are extensively used in conveyorized mines, but no suitable, equivalent equipment, is available to provide these benefits to hard rock mines of low to medium headroom. A hard rock crusher capable of easy movement and readily disassembled would allow use to belt conveyors and could improve the general safety and productivity of any underground ore hauling system. This report summarizes proposals and findings made in conjunction with the newly designed M-44 Low Head Portable Crusher which is believed well capable of meeting the requirements of a "portable, underground, hard rock" machine as previously defined in earlier reports. Data gathered by use of the 1/4 Scale Model of the M-44 has substantiated and verified the concept sufficiently to justify construction of a full-size machine for further testing under actual mine conditions.

Jan 1, 1978

By C. R. Summers, J. N. Murphy

In response to the Coal Mine Health and Safety Act of 1969, mandatory noise standards have been developed that specify time-noise limits of mine personnel exposure. Most affected by elevated noise levels is the pneumatic roof bolter operator, both in terms of levels near or in excess of 115 dbA and in terms of length of exposure. Therefore, the principal emphasis of this Bureau of Mines report is on pneumatic drill noise control. It is not the intent of this report to suggest any drill redesign; instead, methods are suggested to reduce the noise level by complementing existing machines. An integral muffler system and a separate muffler system were tested in an attempt to lower pneurnaric drill noise levels. Pneumatic drills, when new, operate at about 115 dbA when drilling in sandstone. Using the drill muffler systems, it was possible to decrease the noise level of a 115 -dbA s rope drill to approximately 100 dbA.

Jan 1, 1974

By Foster Fraas

One of the lithium minerals most widespread in the earth's surface is spodumene (Li2O-A1203-4Si02) a lithium aluminium silicate. For some time, deposits of this mineral were known to exist in the Black Rills of South Dakota, but it was only quite recently that Hess4/ pointed out the great magnitude of the low-grade e deposits it s in North Carolina. The theoretical lithia (Li20) content of spodumene is 8.04 percent. The only other minerals with such high lithia content are the phosphates, but these occur only in pockets and are not in extensive deposits5/. Actually, however, the lithia content in spodumene is never found to be this high, being nearly always below 7 percent for the pure mineral, and part of the lithia is apparently replaced by other alkalies.

Jan 1, 1937