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By E. E. Maust

The present work is part of an ongoing Bureau of Mines effort to provide a better understanding of the fundamental phenomena involved in sulfide flotation, the role of oxygen in xanthate adsorption being one essential issue. Galena was chosen as the material around which to develop a conceptual model, partly because of its demonstrated oxygen sensitivity and partly because information on its properties and flotation behavior constitutes the largest part of the fundamental information available on sulfides of commercial importance. The model is formulated primarily in terms of surface electronic energy levels produced by oxygen and xanthate and is further developed using existing experimental evidence and its implications. Four major functions of oxygen are elucidated, and the relationship of these to the formation of lead xanthate, dixanthogen, and a surface compound is discussed. Though yet incomplete, the model provides a useful framework within which the results of diverse experiments can be related to one another in their proper perspective, as shown by a brief discussion and resolution of some apparently discordant results reported in the literature.

Jan 1, 1976

By C. P. Bowie

For years many oil producers have believed that often low-pressure oil- and gas-bearing strata have been over coked in fields where the rotary system of drilling has been used. Collom3/ gave as a reason for this condition that because the mud fluid was thick, the oil or gas stratum was plastered and sealed as the tools passed through it and no oil showed at the surface. Although this observation was made 15 years ago, it may often still be true notwithstanding modern developments in coring and electrical logging. Operators have believed, also, that mud fluid does not solidify behind the casing. Lewis and McMurray4/ stated: "All the evidence obtainable from practical experience points to the fact that the mud fluid properly mixed and employed does not solidify behind the casing, even in deer wells and after long periods."

Jan 1, 1937

By W. M. Dressel

The Federal Bureau of Mines has obtained data by differential thermal analysis of the various minerals that represent the nation's resources in manganese. These data are supported by X-ray diffraction analysis, chemical analysis, mineralography, and optical mineralogy, and provide fundamental information on the response of each mineral to thermal treatment in oxidizing, reducing, and neutral atmospheres. The information can be applied advantage¬ously in the identification of manganese minerals. Its greatest potential value, however, lies in the application of the quantitative data on the reaction temperatures, rates, and products to the more efficient extraction of manganese from U.S. ores. Thermal analysis curves are presented for certain manganese minerals, namely hausmannite, bixbyite, braunite, pyrolusite, lithiophorite, cryptomelane, hollandite, manganite, rhodochrosite, and rhodonite. The original minerals and the products of their thermal decomposition were identified by X-ray diffraction analysis, supplemented by chemical analysis and mineralogical identification.

Jan 1, 1961

By David C. Byrne

PURPOSE: Evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. RESEARCH SUMMARY: The results of previous NIOSH research show that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and gender. Using hearing thresholds at 4,000 Hz as an indicator, coal miners experience hearing loss 2.5 to 3 times greater than would be expected for persons not exposed to occupational noise. At age 50, 90% of coal miners and 49% of metal/nonmetal miners were found to have a hearing impairment. In comparison, only 9% of a nonoccupationally exposed control group had a hearing impairment at age 50. There are numerous barriers to the prevention of hearing loss among miners. In an effort to overcome some of these obstacles, this work was initiated to evaluate practical technological advances in level-dependent hearing protectors and inexpensive personal acoustic monitors. Experiments will involve analysis of this new technology under both laboratory and field conditions. Laboratory components will consist of controlled studies using an anthropometrically correct test fixture as well as human subjects to evaluate the adequacy/effectiveness of various hearing protective devices. Electroacoustical performance testing of new noise monitors will also be conducted in a laboratory setting. Subsequent field studies will determine the actual usefulness and practicality of the personal protective/monitoring equipment as used in different mining situations. It is anticipated that increased on-the-spot awareness of hazardous noise levels and the availability of better-suited hearing protectors will provide a degree of protection beyond what is currently attained in different mining environments. Therefore, the intent of this project is to identify and adapt new acoustical technologies and products that have a direct application to individual mine workers. With increased knowledge of these technological advances, a greater demand for similar devices will likely occur, which, in turn, will lead to a better understanding and awareness of hearing loss prevention methods throughout the mining community. The ultimate goal is for widespread integration of useful hearing loss prevention products and devices into the daily routines of miners

Jan 2, 2000

By Jon K. Ahlness

The Bureau of Mines conducted laboratory and field experiments to determine tne amount of permeability reduction in uranium sandstone after its exposure to different drilling fluids. Seven polymer and two bentonite fluids were laboratory-tested in their clean condition, and six polymer fluids were tested with simulated drill cuttings added. Sandstone cores cut from samples collected at an open pit uranium mine were the test medium. The clean fluid that resulted in the least permeability reduction was an hydroxyethyl cellulose polymer fluid. The greatest permeability reduction of the clean polymers came from a shale-inhibiting synthetic polymer. Six polymer fluids were tested with simu-lated drill cuttings added to represent field use. The least permeability reduction was obtained from a multipolymer blend fluid. A field experiment was performed to compare how two polymer fluids affect formation permeability when used for drilling in situ uranium leaching wells. For this test, the polymer fluid with the best laboratory results (multipolymer blend) was compared with a commonly used polymer fluid (guar gum) that gave poorer laboratory results. When fluid injection rates for the four wells drilled with the guar gum were compared with those for the four drilled with the multipolymer blend, no statistically significant difference was found.

Jan 1, 1984

By H. Tomlinson

This circular is one of a series of papers on coal mining methods and costs which being prepared by the United States Bureau of Mines for the purpose of making available to those interested in the industry a knowledge of the mining methods employed, the places here mechanical and hand loading are practiced, and coat data on the several operations pertaining to the removal of coal from the working faces and its transportation to the tipple for loading into railroad cars. Mining costs are governed by the relative efficiency of the mining method employed. The method is selected for Its adaptability to the local natural physical conditions such as the nature and thickness of the coal bed, its dip, the character of the coal, and the thickness of the overlying strata.

Jan 1, 1930

By Maria I. De Rosa

The U.S. Bureau of Mines performed experiments to determine if primary gas toxicities that evolve during the early (~300° C) and later (~.400° C) combustion stages of polyvinyl chloride and chlorinated brattices could be predicted by a smoke particle characteristic, which could be used as a simple and inexpensive test parameter. The experiments were conducted in an approximately 20-L furnace at set furnace temperatures of 2500 and 1,0000 C, for 14 min duration, with an airflow through the furnace of 10 L/min. The variables studied, as a function of time, were the hydrogen chloride (HCl) and carbon monoxide (CO) concentrations, sample and furnace temperatures, the sample mass weight loss, the average smoke particle diameter (dg and number concentration (no), and the product of the average smoke particle diameter and concentration (dgno)' Results show that the inverse of the smoke particle diameter-concentration (l/dgno) correlates directly with the primary gas toxicities evolved during both stages of combustion.

Jan 1, 1989

By Frederick W. Lee

List of contributing editors of Geophysical Abstracts:

Sep 1, 1932

By J. D. Davis

The carbonizing properties of No. 2-bed coal from the Bartoy mine and No. 5- or Miller-bed coal from the Wilkeson-Miller mine, both at Wilkeson, Pierce County, Wash., were determined by the Bureau of Mines-American Gas Association (BM-AGA) method. Tests were made in the 13-inch retort at 500°, 600°, and 700° C. and in the 18¬inch retort at 800°, 900°, and 1,000° C. Fischer low-temperature and United States Steel Corporation high-temperature assays were made and the results compared with those of the BM-AGA tests at corresponding temperatures. Agglutinating and plastic properties were determined, and chemical and petrographic analyses were made. The No. 2 bed is 58.5 to 88.0 inches thick at three points sampled in the Bartoy mine. The coal is 98 percent bright and contains only a trace of fusain. A composite of three mine samples contained 13.8 percent ash. The washed sample, which was used in the tests described herein, contained 11.4 percent ash, 2.2 percent moisture, and 0.6 percent sulfur upon the as-carbonized basis and 68.4 percent fixed carbon upon the dry, mineral-matter-free basis. The heating value was 15,183 B. t.u. per pound upon the moist, mineral-matter-free basis. No. 2 therefore ranks as a high-volatile A coal and is very high in that, rank. The ash softens at 2,910° F. Except for its ash content, which is higher than the limit of 9.0 percent specified by the American Society for Testing Materials, No. 2 coal fulfills the requirements of a coking coal. It also is classed as extremely friable, the friability being 88.0 percent. The agglutinating index (7.6 for the 15 : 1 ratio of silicon carbide to coal) is high, and the plasticity as indicated by the Gieseler test (60 divisions per minute) is low for a high-volatile A coal.

Jan 1, 1942

By R. H. Grau, A. Sainato, S. J. Schatzel, T. M. Kohler, A. T. Iannacchione

This Bureau of Mines research study found gas emission rates from an advancing face, and flows and pressure of gas from an exploration drill hole were dependent upon the geology of salt encountered in a domal salt mine. Normal production-grade "pure" salt adjacent to an anomalous' zone was found to have a methane emission rate of less than 5 ft3/ ton (0.1 m3/t) of mined salt from a room advanced by a continuous miner. Extremely low gas flows [less the 4 ft3/h (0.1 m3/h)] and lack of pressure buildup were also observed from this normal salt in a 154-ft (47-m) exploration drill hole. These data indicate that methane emissions should not be a problem when mining in this type of salt. In the adjacent anomalous zone, methane emission rates ranged from 15 to 70 ft3/ton (0.4 to 1.8 m3/t) of mined salt from an advancing face. Gas flows of approximately 42 ft3/h (1.2 m3/h), and pressures in excess of 900 psig (6,200 kPa) were observed in an exploration drill hole when the anomalous zone was encountered. This information suggests a greater methane emission hazard from the anomalous zone than from the associated normal salt. If this trend of increasing emissions problems associated with anomalous zones of salt is common with similar anomalous zones encountered or observed in other domal salt mines, then special control strategies should be employed to minimize this potential mining hazard.

Jan 1, 1984

By B. W. Madsen

The Bureau of Mines conducted a large-scale (6.4 t), long-term (2,165 days) test to gain a better understanding of the leaching characteristics of chalcopyritic ores. An ore sample containing 0.77 pct Cu was leached in a fiberglass column by downward percolation of acidified ferric sulfate solutions. Three sets of leaching conditions were investigated: (1) ambient temperature leaching, (2) elevated temperature (50° to 60° C) leaching, and (3) elevated temperature leaching after inoculation with thermophilic bacteria. Leaching at ambient temperature resulted in a copper extraction rate of 0.44 pct per 100 days. Increasing the temperature to 50° to 60° C resulted in decreased activity of natural mesophilic bacteria, and the leaching rate decreased to 0.22 pct per 100 days. The pH was lowered from 2.0 to 1.6, and nutrient solutions that contained thermophilic bacteria were added. This procedure resulted in an increase in the ferric-to-ferrous iron ratio and an increase in the copper leaching rate. However, the increased leaching rate was not sustained, and 120 days after inoculation the bacterial activity declined, the ferrous iron content increased, and the copper leaching rate decreased.

Jan 1, 1983

By Young W. A.

The Eagle Silver mine is in the Rush Valley mining district, Tooele County, Utah, and is now operated by the Hampton Mining Co. The property, originally referred to as the Argent, is reported to have been one of the first discoveries in the district. The early operators mined ore to a depth of 850 feet, at which point the property was abandoned because of excessive water. During 1905 the Honerine tunnel was driven into the area approximately 1,800 feet below the collar of the Argent shaft. This tunnel served to drain the levels above and operations were resumed. Ore deposits in the Eagle Silver mine occur in the Galena King lime-stone, a 20-to 60-foot member of interbedded quartzite and limestone in the Oquirrh formation of Pennsylvanian age. This member has been faulted along the bedding, forming the Galena King gouge. Mineralization commonly occurs in or near this gouge area in a brecciated, highly altered, pipelike zone. The known ore shoots occur in association with the breccia pipe, commonly adjacent to cross faulting and porphyry intrusions. In general, two ore shoots have been mined on the upper levels of the mine, one lying to the east and the other to the west of the breccia zone. The Bureau of Mines diamond-drilling program was begun during the latter part of 1948 and completed early in 1949. Nine holes were drilled, aggregating 852.8 feet. Sludge and core samples from mineralized sections were analyzed in the Salt Lake City laboratories. A total of 87 sludge, 71 core, and 11 chip samples was submitted for analysis.

Jan 1, 1950

By Terry R. Neumann

In 1987 and 1988, the U.S. Bureau of Mines conducted a mineral resource investigation of the 31,400-acre Muddy Creek Wilderness Study Area (UT-060-007). The investigation was requested by the Bureau of Land Management and authorized by the Federal Land Policy and Management Act of 1976 (Public Law 94-579). The study area is located in Emery County, Utah, about 50 air-miles southwest of Green River, Utah. The wilderness study area is in the San Rafael Swell region of the Colorado Plateau Physiographic Province. Rocks in the area consist of gently dipping sedimentary strata of Permian, Triassic, and Jurassic age.

Jan 1, 1988

By A. C. Smith

The U.S. Bureau of Mines evaluated the effectiveness of automatic water sprinkler systems on the suppression of incipient and propagating conveyor belt fires under ventilated conditions. Large-scale experiments were performed at airflows ranging from 1.1 to 4.6 m/s. In incipient fire experiments with 100°C, standard-response sprinklers installed above and between the belts, the sprinklers activated later, the peak heat release rates were larger, and more belting was consumed at the higher airflow. In similar experiments with 74 °C, fast-response sprinklers, the sprinklers activated at the same heat release rate for both high and low airflows, but the peak heat release rate and amount of belting consumed was slightly higher at the lower airflow. In incipient fire experiments with sprinklers located only above the top belt, the heat release rate and amount of belting consumed was larger at the higher airflow. The propagating fire experiments showed that sprinklers located above and between the belts were effective in stopping flame propagation. Peak heat release rates and amount of belting consumed were larger at the higher airflows for both the 74 °C, fast-response and 100 °C, standard-response sprinklers. The sprinklers were equally effective at each airflow.

Jan 1, 2010

By E. J. Gleim

For many years mining men have sought for a portable device that would be direct reading and permit more positive detection of methane than was possible with flame safety lamps, which depended so largely on the training, skill, and personal ability of the user. Through the years, after the discovery that methane contributed to many mine explosions, considerable effort and large sums of money have been expended in searching for and developing instruments that would be practical, and, at the same time, reliable and safe to use. Very early in the history of the Bureau of Mines, some of its engineers were unsuccessful, after many trials, in attempts to develop such an instrument. Commercial firms, however, persisted in research until today a number of instruments are on the market that have proved to be practical in coal-mine service. It is hoped, however, that further research will bring about improvements in accuracy and other desirable features. BUREAU OF MINES STANDARD FOR METHANE DETECTORS The Bureau of Mines recognized the need for establishing minimum requirements on which to base official approval of suitable Instruments. This standard was prepared as Schedule 8. It was revised before being issued in printed form. The revision was published as Schedule 8A in 1920 and was revised on two other occasions. The present edition, known as Schedule BC, was issued October 31, 1935.

Jan 1, 1954

By E. C. Perkins, R. S. Lang, D. M. Taylor, H. Dolezal

The amenability of titaniferous slags and domestic mineral concentrates to chlorination was determined in a 6 - inch diameter fluidized bed chlorinator . Ilmenites from Valley County , Idaho ; Aiken , S.C ,; Trail Ridge , Fla .; and MacIntyre , N.Y .; and a titaniferous magnetite from Iron Mountain , Wyo . , were used in preparing the slags . The domestic minerals tested were an ilmenite concentrate from Valley County , Idaho , and a rutile concentrate from Magnet Cove , Ark . A high - grade Australian rutile was used as a standard for comparison . The impurity content of the slags and minerals tested , which was the most critical factor affecting their performance , was dependent on the geographical source of the material . All of the materials tested were amenable to chlorination in a fluidized bed although some required special operating conditions . Titanium extractions and chlorine utilization were over 90 percent for most of the slags and the Australian rutile . The Valley County , Idaho , ilmenite performed well in the reactor despite its 34 percent iron content .

Jan 1, 1963

By Carlton E. Brown

This report contains information on the cells or containers used to hold a known small depth (usually 1 mm. or less) of the dust-containing liquid from impinger, 5/6/ filter-paper,7/ and other samples collected from the air while the particles revealed by a microscope (equipped with a 16-mm., 0.25- or 0.50-N. A. objective and ordinarily used with axial light-field illumination) are counted in order to obtain an index of the concentration of dust in the sampled air. Information is given on such subjects as the kinds of cells available, kinds used, actual depths of cells, and construction of simple, inexpensive cells. ACKNOWLEDGMENTS The interest, encouragement, and assistance received from H. H. Schrenk, chief chemist of the Health Division, in the preparation of this report are gratefully acknowledged, as 'is all other assistance received.

Jan 1, 1945

By C. M. McKinney

This report contains Bureau of Mines routine crude-oil analyses of 20 samples from5 areas on the arctic slope of Alaska. Two samples were condensates from the South Barrow gasfield, Barrow Lakes area. The remaining 18 samples were crude oils from the following areas: Barrow Lakes, 1 seepage sample; Umiat, 10 well samples; Cape Simpson, 1 seepage sample and 3 well samples; Fish Creek, 2 well samples; and Wolf Creek, I well sample. Table 1 summarizes information on the origin of the crude-oil samples, and table 2 summarizes characteristics of the samples. Item numbers in both tables correspond to item numbers of the analyses at the end of this report, and the samples are referred to by these numbers throughout the text.

Jan 1, 1959

By R. E. Peterson

Scrap iron is partially oxidized at elevated temperatures in the selective oxidation process to produce iron oxide and a dense residual metal of high purity. Investigation of the process was confined to converting automobile hulks into useful products. In one test series, compressed, sheared automobile scrap was processed at 1,000° C in a 36-foot-long rotary kiln at feed rates ranging from 300 to 1,200 lb/hr. Less fuel was required to maintain the temperature at the higher feed rates because of the heat generated from the burning of the combustibles and the oxidation of the iron. The bulk density of the residual metal exceeded 75 pounds per cubic foot. In an attempt to lower the quantity of contaminants in the residual metal, another test was designed using automobile hulks which had been prepared by ripping, a low-cost method of scrap fragmentation. Before oxidizing the ripped scrap approximately 62 percent of the total copper was removed in a tumbling, screening, magnetic separation and hand-sorting system. Cast iron made from the residual metal obtained by selective oxidation contained 0.15 percent copper; iron oxide scale obtained from the kiln averaged 0.13 percent copper. Pellets made from the scale demonstrated compressive strengths necessary for blast furnace reduction; lead and zinc were removed by volatilization when the induration was performed in a reducing atmosphere.

Jan 1, 1972

By Oliver C. Ralston

Fluorescence is of growing interest to the mineral industry because certain minerals may be detected thereby and because, as shown in figure 1,4/ many minerals (natural or synthetic) are needed in tubes and lamps. The use of fluorescent lighting is expanding, and large numbers of lamps of many sizes and shapes are being made and used in works, factories, stores, offices, homes, and in photography. Fluorescent tubes, as distinguished from clear tubes filled with neon, argon, or other rare gases through which a current of electricity passes, fluoresce owing to specially, selected and prepared minerals placed in the tubes. Luminous chemicals and paints also contain special minerals and are used in similar applications; therefore, these also will be considered in this report. Although the quantity of minerals (in tons) that are used for fluorescent purposes is small, and probably will continue to be so, this use is significant because it exemplifies a requirement for "pure" minerals in which a trace of contaminant as" minute" as one part in ten million may distinguish between the acceptance or rejection of a particular material. This extreme purity makes synthetic minerals almost essential, and natural mineral's are now little used.

Jan 1, 1944