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By H. S. Martin

This paper, describing the concentrating practices at the plants of the Utah Copper Co., is one of a series being prepared by the United States Bureau of Mines in which the data are given in as nearly uniform c manner as possible. The Magna mill is 19 miles west of Salt Lake City on the routes of the Lincoln and Victory highways, and the Arthur plant is 1 mile west of the Magna mill. Both are on the main road west of the town of Magna and east of the town of Garfield.

Jan 1, 1931

By I. L. Nichols

The inplace cyanidation leaching of gold from placer deposits is a potential method for treating gravels too deeply buried and too low in gold content to be processed economically by conventional dredging methods. Laboratory experiments were made to evaluate those placer cyanidation factors adaptable to small-scale studies. The variables investigated included gold particle size and location in sand beds, cyanide solution flow rate, and cyanide solution strength as factors affecting gold solubility rates. The solution flow rate, in turn, was influenced by variables such as bed slope, solution head pressure, and sand size, and the effects of these factors were studied. Free gold, minus 150-mesh and finer in size, is rapidly dissolved by dilute cyanide solutions from mixtures of gold and silica sand prepared to simulate placer deposits. About 94 percent of minus 325-mesh free gold was extracted in 5 hours from silica sand mixtures, and 94 percent extraction of minus 150-mesh gold was obtained in 21 hours with 0.1 percent NaCN solutions. Moving solutions were almost twice as effective in leaching free gold from silica sand mixtures than stagnant solutions.

Jan 1, 1971

By S. P. Kinney

The efficient operation of a blast furnace is primarily dependent upon efficient contact between the descending stream of solid materials and the ascending stream of gas. The United States Bureau of dines is conducting a program of research dealing with the interior of the present-day furnace. The work is being carried oat by.(1) observations on commercial furnaces end (2) experiments in the laboratory. Through the courtesy of the officials of the Illinois Steel Co. it was possible to make a detailed investigation of the interior of the shaft of Number.4 furnace at the company's South Works, South Chicago, Ill. The experimental work is to be reported in a U. S. Bureau of Mines bulletin which will include the results of several thousand observations on the interior of the shaft of this furnace. Such of the data as are presented later in this paper constitute only a brief summary.

Jan 1, 1929

By K. E. Robinson

This study is the extension of an investigation of reclamation of floodplain areas in the Coeur d'Alene Mining District, Idaho, that are unuseable in their natural condition, by construction of landfills with mill tailings. The study develops a valley-wide tailings disposal plan to utilize 20 potential landfill sites on floodplain areas and presents measures for reclaiming the sites for subsequent productive use. Field and laboratory testing on a test section and two abandoned impoundments support the use of hydraulically deposited tailings for landfill construction. Hydrological testing has shown that controlled discharge from tailings impoundments results in contaminant levels in the discharge below regulated standards. Additional testing indicated that compacted soil liners and pond management provide adequate contaminant abatement where acid-generating tailings are encountered. Mechanical compaction, including surcharge loading, upgrades foundation support capacity so that construction on the surface of tailings deposits is feasible. On completion of the testing program, the test sections were abandoned and rehabilitated. Details concerning potential landfill sites have been refined. At recent production rates, the 20 sites would result in 680 acres of reclaimed land, while providing a minimum of 40 years of tailings storage capacity. A general design has been developed for the retention dikes. Aspects of embankment stability, including liquefaction are discussed, and are shown to provide an adequate factor of safety under the anticipated range of operating conditions.

Jan 1, 1983

By Robert E. Wood

The compressibility factors, Z, of helium, nitrogen, and helium-nitrogen mixtures in the three-dimensional space of temperature, pressure, and gas composition have been related to the Leiden form of the virial equation of state. The dependency of virial coefficients through the fifth on temperature and gas composition has been established for the temperature range 133.15° to 748.15° K. Compressibility factors, Z, have been computed from the equation of state and tabulated as functions of gas composition, pressure, and temperature. Tabular values of Z are presented for 30.00 through 100.00 percent helium for temperatures from 240° through 700° R for pressures from 14.696 through 3,050 psia and for temperatures from 720° through 1,300° R for pressures from 14.696 through 1,500 psia. Tabular values of Z are presented at increments of 5.00 percent helium and 20° R, and, for pressures greater than 50 psia, at increments of 50 psi.

Jan 1, 1967

By David A. Summers

The use of high pressure fluid cavitation is investigated as a means of breaking an ore into its constituent grains. This Cavitational Rock Dissagregation (CRD) is found to be possible and effective in breaking down galena ore, both in sandstone and dolomite host material. The technique did not work as well in comminuting and cleaning oil shale, because the cavitation drove the oil into emulsion with the water. The presence of dominant bedding in the rock also caused preferential breakage to these lines, rather than to the individual grain boundaries. This problem was also encountered in tests on igneous ore where weakness plants of the overall ore proved weaker than the boundaries of the individual grains. It was found that the prevailing expression of cavitation erosion dependence on pressure was not absolutely valid. In contrast it was found that CRD is much more sensitive to jet flow diameter, and when this was recognized it was found possible to erode rock with compressive strength of up to 350 MPa with operating jet pressures of 10 MPa.

Jan 1, 1982

By R. H. Thompson

Preliminary safe distances for blasting wiring from typical electromagnetic sources are presented. The distances are for underground coal mines and electromagnetic sources in the frequency range below 10 MHz. The distances are based on measurements performed at 3 locations in each of 3 coal mines. The measurement apparatus, measurement procedure, measurement results and the rationale used in the calculation of the safe distances are all described. The safe distances presented are dependent on the measurement results and their interpretation. More measurements are clearly necessary to establish the validity of the suggested distances.

Jan 1, 1985

By Lloyd A. Morley

This eight-chapter document is the second volume of a two-volume report that presents a comprehensive outline of coal-mine electrical power systems from theory to practice. Together, the two volumes contain the vital aspects that go into planning and designing a mine power system. Building upon Volume I, the subject of protective equipment and relaying starts Volume II, first as an introduction in Chapter 8, then by a treatment of device selection in Chapter 9. Chapter 10 continues system protection in terms of transients and overvoltages. Chapter 11 describes the design of major power equipment, including power centers, switchhouses, and substations. Solid-state applications in mining are given in Chapter 12, and batteries and battery charging are discussed in Chapter 13. Chapter 14 covers electrical-equipment in hazardous locations of mining operations. The report concludes with Chapter 15, a discussion of electrical maintenance as well as some specific mine electrical problems. Information on surface and underground use is included in all these chapters. An index finishes the documentation and is cross-referenced to both report volumes.

Jan 1, 1982

By J. B. Rosenbaum

Prolonged laboratory and limited pilot plant tests have shown that the Bureau of Mines buffered S02 -H2S process is capable of removing 95 to 99 percent of the S02 from industrial waste gases. Most of the S02 is converted to elemental sulfur; only about I percent converted to sulfate The process comprises (1) washing the flue gas to remove particulates and S03, (2) absorption of the S02 in citric acid or other carboxylate solution, (3) reaction of the loaded solution with H2S in a closed vessel to precipitate the absorbed S02 as elemental sulfur, and (4) separation of the sulfur from the regenerated solution by oil flotation and melting. Two-thirds of the molten sulfur is converted to H2S for use in the sulfur precipitation step by reacting sulfur vapor with natural gas and steam in the presence of an alumina catalyst. The chemistry and mechanism of the process are described, initial laboratory and pilot plant data are summarized, and second-generation laboratory operation and pilot plant design are reviewed. Preliminary cost estimates are presented for recovering sulfur from copper smelter gas, powerplant flue gas, and Claus plant tail gas.

Jan 1, 1973

By O. C. Blade

Total sales of diesel fuel in the United States continue to Increase. This growth is due primarily to two causes: More conversion to diesel units by the rail-roads In recent years, and the greater use of diesel engines in trucks, busses, and tractors. Following are some figures on the distribution of the fuel computed from data issued by the Bureau of Mines.2/ [ ] Deliveries of diesel type fuel from refineries totaled 91,522,000 barrels during the first six months of 1955,3/ corresponding figure for 1954 was 91,170,000 barrels. Information on the properties of this engine fuel is very important to the petroleum industry, engine manufacturers, and consumers. To supply such information the American Petroleum Institute and the Bureau of Mines, United States Department of the Interior, under cooperative agreement, are conducting annual surveys of diesel fuel oil produced in refineries in this country.

Jan 1, 1955

By Kim B. Shedd

The U.S. Bureau of Mines Particulate Mineralogy Unit examined the habits of six zeolite minerals commonly occurring in domestic zeolite deposits. Mineral habit is of interest because current theory on the potential for sarcoma production in test animals emphasizes the size and shape of mineral particles, without regard to composition or structure. A scanning electron microscopic study revealed that, of these six minerals, only mordenite and erionite crystallized in acicular to fibrous habits, The fibrous varieties of these two minerals were characterized by size and shape on the transmission electron microscope, and their dimensions were compared with those of asbestos and amphibole cleavage fragments. When comminuted, these two minerals possess "fibrosity indices" similar to those of amphibole cleavage fragments. One sample, a rare woolly erionite, has uniform widths, large aspect ratios, and a "fibrosity index" similar to those of asbestos.

Jan 1, 1982

By Kristine M. Krajnak

Occupational exposure to hand-arm vibration through the use of powered hand tools can result in reductions in tactile sensitivity, grip strength and manual dexterity. In fact, even acute exposures to vibration cause shifts in vibrotactile thresholds in exposed fingers (2,4,5). Although reductions in tactile sensitivity after acute vibration exposures are transient, cellular changes associated with this shift in sensitivity could lead to the more permanent reductions in tactile sensitivity that are a common symptom of hand-arm vibration syndrome (HAVS). Methods Animals. Male Sprague Dawley rats (6 weeks of age) were used for all experiments. Animals were housed in AAALAC accredited facilities, and all procedures were approved by the NIOSH Animal Care and Use Committee and were in compliance with the CDC guideline for care and use of laboratory animals. Vibration exposures were performed by restraining rats in a Broome-style restrainer, and securing their tails to the vibration platform using 6 mm wide straps that were placed over the tail every 3 cm. Restraint control animals were treated in an identical manner except that the tail platform was set on isolation blocks instead of a shaker. Tail temperature and current perception thresholds (CPTs). Rats were exposed to 4 h of tail vibration (125 Hz, 49 m/s2), or restraint. Tail temperature was collected prior to and immediately following the exposure using an infra-red camera. Sensory neuron function was assessed by measuring CPTs with a Neurometer (Neurotron, Baltimore, MD). Transcutaneous nerve stimulation was applied to the C10 region of the tail. Three frequencies were used to test specific fiber types (5 Hz – C, 250 Hz - Ad, and 2000 Hz – Aß). The intensity of the stimulus was automatically increased in small increments until the rat flicked its tail. Tests at each frequency were repeated until the animals displayed 2 responses that were within 2 CPT (or 0.02 mA) of each other (2-4 tests/animal). CPT tests were performed prior to the exposure, immediately following the exposure, and 24 h after the exposure. Data Analyses. Temperatures were analyzed using a one-way ANOVA with animal as a random variable. ANCOVAS were used to analyze the CPTs at each frequency. Temperature at the time of the CPT test was used as a covariate, and animal was used as a random variable Results Tail temperatures declined between pre and post exposure (F(1,25) = 62.85, p < 0.001; mean ± sem pre 25.96°C ± 0.42, post 20.71°C ± 0.77), but were back to baseline levels by 24 h after the exposure in both groups of rats. The ANCOVAs demonstrated that exposure to a single bout of vibration did not alter sensitivity of C (5Hz) or Ad (250 Hz) fibers to stimulation.

Jan 6, 2006

By Donald R. Johnson

Apparatus providing simultaneous differential thermal analysis, thermo-gravimetry, and evolved gas analysis, has been developed by the Bureau of Mines specifically for thermal study of oil shale and other solid, natural fuels. The apparatus is described in detail, and simultaneous analyses on a single sample of an oil shale mineral, nahcolite, and a thermal analysis demonstration compound, calcium oxalate monohydrate, are presented to demonstrate the instrument&apos;s capabilities.

Jan 1, 1970

By Thomas O. Glover

Cameroon&apos;s mineral industry continued to be dominated by crude petroleum. The country&apos;s economic development depended on the production and export of crude oil. Oil output was estimated to be 56 million barrels in 1984 compared with 47 million barrels in 1983 and 39 million barrels in 1982. The country&apos;s only refinery processed approximately 16,000 barrels per day of crude oil in 1984, operating at slightly over 50% capacity. This volume, however, supplied the domestic need for motor fuel and heating oils. Cameroon&apos;s economy continued to expand despite problems and setbacks stemming from the attempted coup of April 6, 1984. Gross domestic product (GDP) growth in 1984 was 6.5%, the same rate as in 1983. Offshore crude petroleum production was the chief factor in the sustained economic growth. The country also maintained a relatively strong balance-of-payments position through oil exports. Investment, ranging up to 25% of the GDP, greatly contributed to sustained growth. The oil sector contributed approximately 14% to Cameroon&apos;s GDP in both 1983 and 1984.

Jan 1, 1986

By Sean Gallagher

Background. There is currently little information regarding factors associated with specific modes of motion segment failure using a fatigue failure model. Methods. Thirty-six human lumbar motion segments were fatigue tested using spinal compressive and shear loads that simulated lifting a 9 kg weight in three torso flexion angles (0°, 22.5°, and 45°). Twenty-five segments failed via fatigue prior to the 10,000 cycle maximum. These specimens were visually inspected and dissected so that the mode(s) of failure could be determined. Failure modes included endplate fractures (classified into nine varieties), vertebral body fractures, and/or zygapophysial joint disruption. Logistic regression analyses were performed to determine whether certain morphometric variables, amount of motion segment flexion, disk degeneration scores, and/or loading characteristics were associated with the occurrence of specific failure modes. Findings. Results indicated that stellate endplate fractures were associated with increased posterior shear forces (P < 0.05) and less degenerated discs (P < 0.01). Fractures running laterally across the endplate were associated with motion segments having larger volumes (P < 0.01). Endplate depression was more common in smaller specimens (P < 0.01), as well as those experiencing increased posterior shear force (P < 0.05). Zygapophysial joint damage was more likely to occur in a neutral posture (P < 0.01). Interpretation. These results suggest that prediction of failure modes (e.g., specific endplate fracture patterns) may be possible (at least for older specimens) given knowledge of the spinal loads along with certain characteristics of the lumbar spine. Published by Elsevier Ltd. Keywords: Lumbar spine; Endplate fractures; Zygapophysial joints; Morphometry; Disk degeneration; Motion segments; Aging

Jan 1, 2006

By Bernard Baum

Combined preservative/fire retardant systems were pressure impregnated into Douglas fir and Ponderosa pine samples and evaluated for decay, flammability, and mechanical properties. The objective of the evaluation was to identify cost-effective systems for use with mine timber, and to provide an information and data base from which Federal code regulations could be established. Thirty systems, based on combinations of commercially available preservatives and fire retardant impregnants and coatings, were applied to Douglas fir samples and evaluated for decay and flammability. The ten most promising systems were ap¬plied to both fir and pine and reevaluated for decay and flammability before and after water leaching. The five best systems were given a thorough laboratory evaluation using both pine and fir. Evaluations included flame spread, smoke density, toxic gases, decay, compressive strength, flammability after artificial weathering, and cost. All systems had acceptable toxic gas levels and smoke densities, but flame spread was only borderline acceptable for most of the samples tested. A trade-off analysis showed Acid Copper Chromate/Fyrprufe with Albi-107A/144 intumescent paint and Koppers NCX to be the-best systems. Recommendations are made for further large-scale testing using the two best Systems.

Jan 1, 1978

By Harry A. Schrecengost

The Bureau of Mines has found considerable lack of uniformity in style and content of record books used for reporting the results of examinations made by coal-mine officials. These books range from elaborate forms designed for specific examining and operating procedures at certain large mines to simple composition books, tablets, and pocket-style notebooks at other mines. Examination of thousands of these record books discloses that the reports of many examinations are so brief and so poorly worded that they cannot be understood readily. The contents, in some instances, appear to be deliberately ambiguous. The value of keeping accurate accounts of safety inspections in coal mines is often underestimated. Well-kept records reflect managerial attitude and indicate well-governed operations as well as training of official personnel to conform to considered policy and regulations and if necessary, may serve as documentary evidence to protect the mine officials and the operators.

Jan 1, 1962

By James W. Hendrix

A survey of endomycorrhizal fungi occurring on orphan coalmine lands in Western and Eastern Kentucky revealed a great diversity of species present. Thus a large number of fungi are available for isolation and evalution for enhancing revegetation of mined land. Endomycorrhizal fungi isolated from orphan mines stimulated growth of sweetgum seedlings on mine soil at low fertilisation but inhibited growth at high fertilization; this growth inhibition at high fertilization did not occur with plants growing on peat-perlite. Banding of endomycorrbizal inoculum was not advantageous, compared with incorporation of inoculum throughout the growth medium, for production of mycorrhizal sweetgum seedlings. Newly reclaimed mine spoils were nearly nonmycorrhizal, compared with land reclaimed four or eight years earlier. A procedure for isolation of single-spore cultures of endomycorrhizal fungi was developed; this procedure is necessary for studies of ecotypic variability. A practical procedure using container-grown Pisolithus tinctorius-infected shortleaf pine seedlings for production of large numbers of bareroot pine seedlings infected with P. tinctorius for mined land reclamation was demonstrated.

Jan 1, 1982

By Floyd C. Bossard

Major air-cooling facilities have been installed and are operating underground in U.S. copper mines (at Butte, Montana and Superior, Arizona), South African gold mines, European coal mines, Zambian copper mines, Kolar gold mints in India, Coeur d&apos;Alene mines of Idaho, plus other locations. Mining districts that utilize spot cooling and local air-cooling facilities would increase the above listing many times. The principal objectives of underground mine air cooling systems are to; 1. Extract heat and water vapor from the mine air and provide for their removal from the mine via (a) water pumped to surface or (b) discharged mine exhaust air. 2. Provide acceptable artificial ambient conditions for efficient working mine development and production areas. 3. Recondition used air, thus supplementing the limited mine ventilation balance. In deep South African gold mines, when rock temperatures exceed about 105°F, cooling of underground air becomes necessary for the poorly ventilated sections of the mine. By U.S. standards, air conditioning in poorly ventilated mines usually commences when the virgin rock temperature exceeds 100°F. On the other hand, well ventilated deep vein-type mines in the U.S. have been able to forego general cooling of mine air until the mines have been extended to such depths that the virgin wallrock temperatures have exceeded 115° - 120°F. It must be noted that spot-cooling of selected development headings may be required in many mines where rock temperatures exceed 100°F. Such local air-cooling practices permit the driving of long headings for exploration or extended development prior to holings which result in establishment of primary ventilation circuitry. The following summary reports on current practices of cooling and dehumidifying mine air. General system descriptions with important details will hopefully permit the reader to gain an understanding of the subject. A list of references is provided for this serious investigator who desires a more thorough knowledge-base and who is responsible for the design of a mine air-cooling system.

Jan 1, 1973

By D. Harrington

Coal mines and mining-, as well as metal and nonmetallic mines and min¬ing, are not inherently unsafe, although mining people think they are and would like to have everyone else think so. It is now being demonstrated that mines can be operated with essentially as much safety as any other major industrial enterprise; but most mining people, including workers as well as officials, have been slow to realize or admit this. In the past, and with most people even at present, the idea has prevailed that it is utterly impossible to operate a mine without accidents. Although, as in all other kinds of industrial activity, it is true that some injury is likely on occasion to occur to some workers and an extraordinary accident may occur to one or more persons under exceptional conditions, mines can be operated with few if any accidents if a reasonable amount of the right kind of precautionary effort is exerted and kept in effect.

Jan 1, 1934