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By Francis E. Federspiel

A mineral purvey of the Granite Chief RARE II area (A5-261), covering about 23,400 acres (9,470 ha) of Tahoe National Forest and the Like Tahoe Management Unit, was conducted by the U.S. Bureau of Mines and the U.S. Geological Survey in 1979 and 1980 (fig. 1). The investigation by the Bureau of Mines indicates that the area has a low potential for mineral resources. Samples taken from prospect pits and favorable outcrops indicate no minable quantities of precious or base metals. Placer deposits are too small and low grade to be considered a resource.

Jan 1, 1981

By William J. Kemnitzer

This study was made to show the growth of petroleum coking and to deter- mine trends and characteristics of marketing and utilization of coke on the West Coast, comparing these data with those of the United States as a whole. An earlier Bureau of Mines economic survey of petroleum coke was made in 1930 before the widespread use of coking processes. Data, derived from published and unpublished literature as well as from interviews with industry representatives, show a marked increase in the production of petroleum coke since the end of World War II. This increase resulted from the need of refiners to upgrade heavy residuums for which the demand was diminishing. Increasing coke production as well as significant market shifts away from California-produced coke have created excessive stocks of petroleum coke on the West Coast. The causes of these market shifts were based mainly on (1) economic factors and (2) certain undesirable qualities of some of the petroleum coke produced in California.

Jan 1, 1965

By J. B. Zadra

After the discovery of the rare-earth mineral deposit in the Clark Mountain area near Mountain Pass, San Bernardino County, Calif., two samples wore obtained through the Mining Division of the Bureau of Mines for investigation of possible method of concentration. Three other samples were received later from different locations in the same area. The rare-earth mineral in this ore had been identified by E. T. Schonk as bastnaesite, a fluocarbonate of the rare-earth metals containing cerium, lanthanum, praseodymium, thorium, uranium, etc. Associated with the bastnaesite were barite, silica, and some calcite. The bastnaesite contained a small amount of iron as a coloration and some manganese. Twenty to fifty percent of the weight of the samples studied was bastnaesite, or ten to twenty-five percent total rare-earth oxides; about half was cerium oxide. Apparently, none of this mineral occurred in pure form. Even the highest-grade particles 'wore contaminated by fine, interlocked grains of barite, calcite, and silica; barite contamination predominated, and the barite was interlocked with varying amounts of bastnaesite. While the specific gravities of pure bastnaesite and barite (approximately 5.0 and 4.50 respectively) differ enough to allow separation by gravity, the interlocking of the minerals nullified this difference. Consequently, only a partial separation could be made by gravity concentration. The extremely fine grained texture of most of the ore prevented grinding to a size that would make concentration by flotation practicable; a partial separation of barite by this means was effected.

Jan 1, 1952

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 Manuel Gomez, V. F. Parry, John B. Goodman

"INTRODUCTION The need for an accurate and precise analytical method for determining moisture in coals of high water content has been recognized by the coal industry as well as the fuel technologist. Interest in this particular phase of coal technology extends back to the early work of German investigators on the brown coals of Central Europe. Studies by these workers led to the establishment of a direct immiscible liquid-distillation method 4/ as the accepted moisture determining technique in European laboratories. Direct moisture determining methods, those methods that utilize various techniques to drive off the water from a given sample of coal and either collect the water in a calibrated receiver or selectively trap the water driven off in a suitable absorber, have found little favor in the United States. They have been treated merely as research tools.5/ The problem of moisture determination in low-rank coals of the United States has not been given much consideration because such coals contribute only about 2 percent of the total United States production. With renewed activity in low-temperature carbonization and with the growth of interest in coal and coal-tar hydrogenation, the American coals of lover rank containing 20 to 40 percent bed moisture will be subjected to extensive investigation. If the low-rank coals of the United States are to be accurately appraised, the need for qualitative and quantitative analytical proceeded becomes more pronounced. These coals, especially the lignites of Texas and North Dakota, are highly susceptible to oxidation, a process that proceeds to a greater or less extort when low-rank, high-moisture coals are treated by oven-drying methods. The extent of this atmospheric oxidation has been described and evaluated by numerous workers. 7/In many respects, the problem of moisture determination in low-rank coals, those found in the United States and the high-moisture coals of Central Europe, is similar. Conversely, the problem of moisture determination assumes a different aspect when the coals of the eastern and the middle-west sections of the United States are considered. Present methods, the loss in weight gravimetic-type procedures, serve adequately to test these low-moisture coals. The determination of moisture in coals containing 20 to 40 percent water should be approached from a direct method rather than from an indirect gravimetic-type procedure because of the oxidative tendencies of these coals and the demonstratrated inability of a loss-in-weight technique to remove all the water in a given sample of coal."

May 1, 1953

By D. E. Wolfson

As a part of its overall program of coal carbonization, the Bureau of Mines is studying the coking properties of coals that may be used for metallurgical purposes. The objectives of this study were given in detail in a previous report.2/ The inherent suitability of coal for metallurgical use depends primarily on (1) chemical composition, (2) preparation characteristics, and (3) carbonization behavior. The first two factors, as well as the available reserves, are considered in selecting coals for carbonization tests. According to the estimate of reserves by Dowd,3/ the recoverable coal in Floyd County in beds 28 inches or more thick, in thousand tons, is as follows: [ ]

Jan 1, 1958

By W. H. Oppelt

A lignite from west-central North Dakota (Mercer County) was dried by the Bureau of Mines by the Fleissner process at saturated steam pressures to 1,500 pounds per square inch absolute (p.s.i.a.). Normally, the process is operated at pressures of 200 to 370 p.s.i.a. At the highest pressure the temperature of the saturated stearn is 596° F. The purpose of the investigation was to evaluate the influence of very high stearn pressure and temperature on moisture removal, steam consumption, and physical and chemical characteristics of the dried lignite. Two drying cycles were used: A normal cycle, corresponding to previously established standard time requirements, and an accelerated cycle, wherein time requirements were determined by boiler capacity and handling speed. Blank tests to determine stearn requirements for heating the empty autoclave were performed for each cycle and each test condition. Moisture removal, final moisture content, net steam consumption, and size stability of the dried lignite were determined.

Jan 1, 1959

By R. H. Grau, S. B. Robertson, F. Garcia, A. C. Smith, T. P. Mucho

Researchers working for the National Institute for Occupational Safety and Health (NIOSH) at the Pittsburgh Research Laboratory are developing ways to protect the health of miners. Part of that effort is devoted to improving the air quality in underground stone mines by developing ventilation techniques that can be used in these types of operations. The air quality in these large opening nonmetal mines can be significantly improved by using diesel particulate matter (DPM) controls along with sufficient ventilation quantities to remove contaminants. Practical methods of ventilating these underground stone mines can be accomplished by using mine layouts that course and separate ventilation air through the use of stoppings. The design, construction, and maintenance of effective stoppings in large openings have been a real challenge to mine operators. Several different types of stoppings have and can be used for this application. The choice of stopping design, material used, and construction techniques should be dependent upon a number of factors such as the intended life and effectiveness desired.

By C. W. Morris

This Final Report describes the major technical activities that were accomplished to produce a comprehensive continuous miner training system (CMTS) for coal industry utilization. The primary product of this program was a continuous miner part-task trainer. It is composed of an interactive computer graphics system combined with the operating controls of a continuous mining machine mounted in a simulated cab. The cab contains an audio system for reproducing continuous miner operational sounds. The trainer is supplemented with a complete set of cognitive materials that provide instruction in the operation, safety and health of continuous miner operations. A complete summary of the field test and evaluation of the CMTS is provided along with a set of recommendations for further training program refinements, expansions, and utilization.

Jan 1, 1982

Four taconite plants were studied to establish the extent of hazard to plant personnel which exists based on long-term exposure to noise. The criteria for evaluation include the 90 dBA and 85 dBA summations of partial exposures. Data from extensive interviews were used to determine all work stations or locations which employees occupied and how much time they spent in ach location in a typical working day. Noise level measurements at every designated location were then made. By means of a computer program, these time and noise level data were us d to find the optimum noise reductions which would be required throughout each plant to meet both noise criteria. Subsequently, each plant was examined in detail so that the apparent sources of noise for each of the locations requiring noise reduction could be delineated. In tabular form, this report presents the hazardous locations for each plant, the existing noise level, the optimum noise reduction which would be required to meet the current and proposed laws, and the sources of noise which produce the existing noise level.

Jan 1, 1977

By Howard M. Stainer

Published X-ray mass absorption coefficients were compiled and tabulated. These coefficients are required for various X-ray analytical techniques. Values obtained from 28 authors are listed for 87 elements with both experimental and calculated points included; the wavelengths range from ~0.01 to 68 A. Representative graphs are presented for six elements (lithium, nitrogen, iron, silver, holmium, and uranium. A 37-item supplementary bibliography is also included.

Jan 1, 1963

By Robert F. Chaiken

The Bureau of Mines is using model ducts lined with coal to study the nature of coal mine fires, their rate of propagation, their influence on ventilation airflows, and their response to sealing and other fire suppression measures. For scale-modeling purposes these studies are being carried out in various size ducts; eventually they will include a full-size mine entry in the Bruceton multiple-entry Experimental Mine. To date, work has been carried out in an insulated 9.l-m-long duct with a 5-cm thickness of coal leaving a 23-by 23-cm square opening for air ventilation. Fire propagation processes in this duct were mainly transient in nature owing to the relatively small length-to-diameter ratio. This report describes the experimental equipment employed and the results obtained to date.

Jan 1, 1979

By M. Mahan, D. D. Blue, O. C. Garst, F. Fraas, L. Fink

"Early in World War II it became apparent that the known bauxite re- serves might not be adequate to supply the demands of the American aluminum-producing industry, as the transportation of bauxite from abroad to this country might easily be interfered with by hostile action. Consequently, the Bureau of Mines set up an intensive, well-integrated program for the production of cell-grade alumina from low-grade domestic ores. This pro-gram of investigation covered the production of alumina from clay, alumite, red mud, and other low- and marginal-grade ores. In line with the Bureau's usual policy of conservation of natural resources, it was decided that the investigation should be extended to cover the production of alumina and other valuable byproducts from aluminum dross.Statistical information showed that during the year 1943-44, an average of 2,900 tons of aluminum dross was generated monthly. This dross, after partial removal of free metal, had an average metallic aluminum content of approximately 9 percent. Some of this dross was produced by the melting of alloyed aluminum; but a large proportion 1,700 out of 2,900 tons - was generated by two producers of primary aluminum, and the dross did not contain an great proportion of alloying metals. Compared with dross from other sources, this 60 percent of the country's capacity can be assumed to have relatively uniform composition. Moreovcr, the problem of collection and distribution can be minimized because of the relatively small number of plants included in the organization of these two producers of virgin metal.Except for large pieces of metallic aluminum that easily can be mechanically separated for remelting, this dross has been discarded and scrapped. Inasmuch as chemical analyses show that the alumina content of dross is far higher-than ordinary ores - 111 percent alumina equivalent in dross compared to 57 percent alumina in bauxite - aluminum dross is a far richer source of aluminum than any known naturally occurring ores. The discard, of this waste material during the war and reconversion periods would be unsound economically. The work reported herein describes tests at the College Park Station of the Bureau of Mines on the recovery of metal, alumina, ammonia, methane, and abrasive-grade corundum from dross."

May 1, 1946

By W. J. Kroll

Despite the fact that barium minerals are plentiful and widely distributed in nature, this element is one that we do not yet know how to prepare cheaply in metallic form. This is due to its chemical activity, as evidenced by its great affinity for fluorine, chlorine, oxygen, nitrogen, hydrogen, and sulfur. Furthermore, it forms a very stable subchloride and subfluoride, which prevents isolation of the metal by fusion electrolysis from a halide bath. A good survey of the metallurgy of barium calcium, arid strontium has been made recently in Light Metals (54,55).3/ Metallic magnesium (46), calcium (83), barium, and strontium (27) reduce each other's oxides. Proof of this can be found in the activation of BaO after reduction with Mg, which leads to the formation of so-called "Maquenne" mixtures (58) used for absorbing gases. However, it is impossible to extract the reduced metal- from the residue, a fact that Guntz (25) attributed to the formation of barium suboxide. There is no necessity for presuming the formation of such a compound, as it has boon established that in the reduction there is always formed an alloy of the alkaline-earth metal with the magnesium, which is capable of producing hydrogen when brought into contact with water. The reduction of alkaline earth-metal oxides with aluminum was observed by Mallet (57) in 1877, but recent investigations have shown that the end product of the reaction is an alloy of aluminum with the alkaline earth metal (1,2). Silicon also has been suggested as a reducing agent, and the results obtained are the same (84,85).

Jan 1, 1945

By J. C. Gerdeen

SAP-S information on the following element types are included in this appendix: Type 1. Three-Dimensional Truss and Bolt Element Type 4. Two-Dimensional Finite Elements Type 8. Variable-Number-Nodes Thick Shell and Three-Dimensional Elements Type 9. Two-Dimensional Joint Element (to be used with Type 4 elements) Type 10. Three-Dimensional Joint Element (to be used with Type 8 elements) Additional SAP4 elements, Types 2, 3, 5, 6, 7 and 12, are also contained in SAP-S and information on these elements is readily available in any SAP4 user's manual. These elements are as follows: Type 2. Three-Dimensional Beam Elements Type 3. Plane- Stress Membrane I-r .n Elements Type 5. Three-Dimensional Solid Elements (8 Node: Brick) Type 6. Plate and Shell Elements (Quadrilateral) Type 7. Boundary Elements Type 12. Three-Dimensional Straight or Curved Pipe Elements

Jan 1, 1976

By W. T. Benson

Peacetime production of mercury in the United States is controlled by world mercury prices, with significant lags to be expected between price increases or decreases and resultant increased or decreased production. Twenty-four mercury-bearing mines and prospects in widely separated districts in western and central Nevada and one property on the Nevada-Oregon border were examined and sampled. The purpose of the project was to determine if some of the properties warranted more extensive exploration work to obtain information on possible reserves of commercial-and sub-commercial-grade ores. The investigation of mercury deposits in Nevada was sufficiently widespread and indicated several areas of interest in the State that merit further exploration work.

Jan 1, 1956

By William M. Hinton

This report describes the approach, procedures, and results of a program to develop training materials for roof bolter operators. The objective of the program was to design and produce a training sequence which would prepare roof bolter trainees for job performance. Data was collected and analyzed using the general procedures of Instructional Systems Development (ISD). Input data came from a previous roof bolter training analysis program. This data was expanded and structured through a series of ISD steps: objectives hierarchies, media selection, syllabus, lesson specifications, and train¬ing materials development. The resulting program consisted of an ordered sequence of 15 lessons. The media mix for the 15 lessons included lectures, slide-tape lessons, and hands-on instruction using operational roof bolters. Contents of all lessons were reviewed and approved by the Bureau. The key recommendations were to (1) validate the materials and measure relative effectiveness of media formats; (2) survey mines for training resources and conditions - match materials to user capabilities, rather than selection state of the art technology/media; (3) develop job performance aids (JPAs) rather than simulators; (4) create a style/media/JPA development guide for use in future projects of this kind.

Jan 1, 1982

By G. Hakes

A data bank on bolter technology was assembled which included state-of-the-art industrial equipment as well as new equipment currently under development for the U.S. Bureau of Mines. This information was augmented by field visits to selected USBM contractors, mine operators and others for the purpose of obtaining a thorough understanding of present coal mine roof bolting safety and productivity problems. These direct contacts provided valuable insight regarding requirements for new bolting equipment necessary to assure wide user acceptance. Using this background material and information, a series of roof bolter concepts was developed offering improved operator safety with minimum impact on productivity. The concepts developed utilize existing componentry and technology wherever possible. All of the concepts feature a fully protected operator station located 6' to 10' outby the active bolt line and the hazardous rotating machinery.

Jan 1, 1978

By Roger M. Turpening

This study was performed to examine the feasibility of using seismic shear waves to detect the presence of abandoned coal mines. !he Antiquity Coal Mine near Antiquity, Ohio was used as a region of known voids. No attempt was made here to accurately locate the mine tunnels if detection was obtained. The results of this study were positive. Sharp changes in the amplitude of the received shear waves were clear indications of the presence of a fluid (gas or liquid) filled region between the source and receivers. When moving the source showed no change in the received signals it was concluded that the voids existed beneath the sensors. Prior to these tests drilling (SM-3) had determined that a void did exist in this area. This void was confirmed by this shear wave test and two additional voids were found.

Jan 1, 2012

By O. Q. Leone

Excellent metal quality, with lower power requirement, is attained in electrorefining titanium by using internal heating of the fused-salt bath. An internal heater provides more effective heat utilization, simplifies structural components in cell design, and prolongs cell life by eliminating direct application of heat to the cell container. This Bureau of Mines report covers one phase of the research in progress at the Electrometallurgical Experiment Station at Boulder City, Nev., for improving the techniques and lowering the total power requirement for electro-refining titanium metal.

Jan 1, 1959