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Improve the dust-control effectiveness of the Rotoclone1 dry-dust collection systems used on surface coal mine drills.

Jan 1, 1994

By Charles L. Parsons

The United States produces all of the fuller's earth used for re- fining petroleum within its borders. On the other hand, most of the fuller's earth used in bleaching edible oils has been imported from England. Recently a few of the refiners of cottonseed oil have begun to utilize domestic fuller's earth, whereas others have been unable to substitute it successfully for English earth in their practice. Many samples of American earth distinctly superior in bleaching power to the English earth have come to the attention of the Bureau of Mines. For these reasons an investigation of the mining, preparation, and use of fuller's earth in this country, especially in its application to edible oils, was conducted in order to ascertain why our own raw material has been deemed inapplicable to our needs. During the calendar year 1912, according to figures of the United States Geological Survey," there were imported into the United States 1,970 tons of unground fuller's earth, valued at $11,619, and 17,139 tons of ground fuller's earth, valued at $133,718, these values being based on the wholesale market price at the port of origin. The addition of transportation charges, commissions, etc., make the price to the American refiner $14.50 to $16 per ton. Accord- ing to the latest figures compiled by the United States Geological Survey, the United States in 1912 produced 32,715 tons of fuller's earth, valued at $305,522, or $9.34 per ton, at the mine. Most of this domestic production was from three plants in Florida and one in southwestern Georgia and was used almost wholly for decolorizing petroleum. A small amount from other localities was used in the refining of edible oils. No figures definitely differentiating fuller's earth from other clays are kept in regard to our exports, but it is certain that several thousand tons of domestic earth was exported to Germany, and it is also true that German refiners of edible oils have

Jan 1, 1913

By H. F. Weaver

The 18th National First-Aid and Mine Rescue Contest was held in the Memorial Auditorium, Buffalo, New Vork, October 5, 6, and 7, 1959. The meet was sponsored by the Federal Bureau of Mines and the Joseph A. Holmes Safety Association, in cooperation with State mine inspection agencies, management and labor of the mineral extractive industries, and other safety minded groups. The Arrangements Committee, as authorized by the General Committee, made a11 the necessary arrangements for conducting the 1959 contest. Members of the Arrangements Committee were: Harry Gandy, Jr. (chairman), National Coal Association; James B. Benson, Southern Coal Producers' Association; Charles Ferguson, United Mine Workers of America; George C. Trevorrow, Bituminous Coal Operators' Association; and James Westfield, Federal Bureau of Mines.

Jan 1, 1960

By L. C. IlsLey

The Bureau of Mines has collected field data and made laboratory investigations of trailing- cable performance in the hope of developing a better and safer cable for use with permissible mining machines . Because of their better insulation and performance , only rubber- sheathed cables were finally considered . The cables tested represented the product of six manufacturers . : After consideration of the results of the preliminary investigations , the conditions under which cables are used in mines , and the better performance of the later types of cables that were submitted as the investigation progressed , the bureau formulated a performance - test requirement and notified the cable manufacturers as follows : The hazards of the trailing cable are such that the bureau has been unable to extend beyond the machine its formal approval to cover the cable as at present developed . However , in the attempt to reduce the hazard as much as possible , cables passing certain tests will be recommended for this service and it is hoped that several cables will be developed to meet this requirement .

Sep 1, 1930

In laboratory tests using reconstructed soil columns, rubber latex showed good sealing efficiency when applied at a rate equivalent to 4000-5000 pounds per acre. Results of field testing, however, were inconclusive. The ideal situation in which latex would coagulate in a narrow zone two to three feet below the surface by reacting with acidic or metallic constituents of the soil was not attained. Rather, the latex was deposited progressively as it passed through the soil (most of it remained in the top foot), the rate of deposition being dependent on soil structure and composition as well as on properties of the latex such as particle size and emulsion stability. Latex stability appears to be a more critical property than latex particle size in controlling penetration. Addition of excess anionic or nonionic surfactants to latex improved its penetration into the soil. A styrene-butadiene (SBR) rubber latex of 2400 Å average particle size with high mechanical stability gave the best balance of penetrating ability and sealing capacity in laboratory tests and this was confirmed in tests on a 5 x 5 foot test plot at Lanse, Pennsylvania. This latex was subsequently applied to three one-quarter-acre plots at Lanse by sprinkler irrigation, and compared to adjacent areas that were sprinkled with water only. Soil moisture measurements did not enable us to judge the effectiveness of the seal because differences between sampling positions were greater than differences between treated and untreated sections, but permeability tests showed that water flow was much slower (90-99% reduction) within the top ten inches of soil in the latex- treated sections. This sealing effectiveness was reduced after wintering. There was no deleterious effect on the vegetation as a result of sprinkling the areas with latex. A laboratory study conducted in a 5 x 5 x 5 foot box containing uniform reconstructed soil from a New Jersey source suggests that latex penetration into the soil in the field occurs mainly through natural macro openings and not through the capillaries of the soil structure. Dilute solutions of ammonium hydroxide or sodium carbonate (with no latex present) were found to seal effectively in laboratory soil columns as well as in field applications. However, since these chemicals are water soluble, the seal is temporary. Raw material costs of latex at the application rates used in the field testing are in the order of $1000 per acre. Equipment and operating

Jan 1, 1972

By Maria I. De Rosa

Table 28 and figure 10 show the number of fires and fire injuries for surface sand and gravel mines by state during 1990-2001. Table 28 also shows the injury risk rates, employees' working hours, and lost workdays. At surface sand and gravel mines, a total of 70 fires with 60 injuries occurred in 29 states during 1990-2001. Fifty-nine of the fires caused 60 injuries (none of the fires involved contractors). The yearly average was 5.8 fires and five injuries. The Ewhr value was 741 x 106 hr (Irr = 0.016), and the LWD value was 6,921. California had the most fires (nine fires and five injuries), followed by Michigan (six fires and six injuries) and Pennsylvania (five fires and five injuries). Of these states, Pennsylvania had the highest injury risk rate value (Irr = 0.052). Table 29, partly illustrated in figure 11, shows the number of fires, fire injuries, risk rates, employees' working hours, and lost workdays by time period. The number of fires and fire injuries show an increase during the second period followed by a decrease during the fourth period followed by a small increase during the fifth period and a sharp decrease during the last period. Employees' working hours increased during most of the periods. The Irr values follow patterns similar to those shown by the injury values.

Jan 1, 2004

By J. S. Browning

The Bureau of Mines investigated the concentration characteristics of high-clay sylvinite ores from potash companies operating in the Permian basin near Carlsbad, N. Mex. These ores, containing 14 to 19 percent K20 and 3 to 5 percent clay slimes, cannot be effectively processed by current commercial flotation methods because of their high clay content. A solution to this problem was shown to be the use of two-stage moderate scrubbing conditions for clay disaggregation and removal as opposed to strenuous attritioning. Bench-scale beneficiation techniques for recovering potash minerals by flotation from the scrubbed material resulted in acceptable product grades and recoveries. By using a coarse grind, emphasis was placed on production of premium granular and coarse products. Flotation results showed that concentrates of 59.6 to 60.4 percent K.0 values can be obtained. Continuous pilot plant beneficiation techniques for recovering potash minerals by flotation resulted in concentrates containing 58.8 to 59.8 percent K20 with recoveries of 69.7 to 81.4 percent of the K20.

Jan 1, 1975

By W. H. Eddy

Laboratory batch and small-scale continuous flotation tests were con-ducted by the Bureau of Mines on a mica waste tailing from Kings Mountain, N.C., to determine the feasibility of producing high-quality mica, feldspar, and glass sand. Mica was recovered by two methods; one was by flotation in an alkaline circuit, which produced a mica concentrate assaying 92.0 percent mica with a recovery of 87.l percent, and the other by flotation in an acid circuit, which produced a mica concentrate assaying 91.0 percent mica with a recovery of 79.4 percent. Continuous flotation processing yielded a feldspar concentrate assaying 1.10 percent Na20 and 13.50 percent K20, with recoveries of 66.4 and 80.6 percent, respectively. The feldspar tailing was high-quality quartz glass sand analyzing 98.6 percent Si02 and 0.02 percent Fe203.

Jan 1, 1969

Develop a method for control of groundwater inflow to chronically "wet" sections of underground coal mines, in order to reduce groundwater interference with mining activity and to minimize acid mine drainage. Approach In eastern coal regions, groundwater stored in fracture zones in the rock mass can create a significant water problem for underground mining operations. Fracture stored inflow to mine workings impedes mine productivity since storage water sources usually release at the active face, creating the poor mining conditions typical of a "wet" section. Fracture water can also contribute to AMD problems when the water subsequently contacts sulfide minerals in the coal, The Bureau of Mines has developed a mine-dewatering method that eliminates many of the problems associated with mine water inflow by draining these fracture zones before the water can reach the developing face and interfere with mining activity. How it Works The dewatering method removes large volumes of the stored groundwater through high-capacity pumping from a minimal number of wells placed strategically on fracture traces (the surface expressions of fractured rock zones). These fracture traces are located through low-level aerial photographic and geologic investigation. As shown on the map, dewatering wells are sited precisely on fracture trace intersections in order to take advantage of the increased pumping capacity gained from these zones of high permeability. Once well drawdown indicates that the stored water is depleted,

Jan 1, 1983

Rapidly identify unstable mine waste embankments and similar dam structures. Approach Aerial photography, geotechnical instrumentation, and telephone or satellite data transmission are used to supplement walk-around inspect ions. How It Works Embankment stability and other indicators of structural integrity are evaluated using aerial photography, and on-site unattended instruments and data transmitting systems. Evidence of external movement and water seepage is obtained from aerial photography and photogrammetric evaluation techniques. Surface points marked by stake- mounted targets are monitored photographically at time intervals of several weeks or months. Photographic measurements of x, y, and z coordinates of these points are obtained from flying a series of photo-runs over the dam.

Jan 1, 1979

By Spencer P. Howell, J. F. Xrawshaw

"A recent premature explosion in a quarry that resulted in the death of nine men and the injury of several others, was directly traceable to a spark from a steam-shovel working under the face directly in front of the hole being loaded. This accident and similar accidents on record in the Bureau of Mines indicates the necessity for pointing out the dangers in quarries of explosives being ignited by sparks emitted from steam shovels and locomotives, and making recommendations for greater safety.Many premature explosions of which the following are examples, have resulted from sparks, both from steam shovels and passing locomotives. (A) The premature explosion occurred during August, 1920 at a limestone quarry, in a 100-foot drill hole, loaded with 1000 pounds of high-grade nitroglycerin and gelatin dynamites. This hole had been loaded with 500 pounds of 75 per cent strength gelatin dynamite, 300 pounds of 60 per cent straight nitroglycerin dynamite, and 200 pounds of 50 per cent straight nitro¬glycerin dynamite; but no steaming had been placed in the hole. The powderman loading the hole saw the spark enter the hole and was able to run a short distance before the explosion took place, thus escaping serious injury. The explosion of this first hole was transmitted to nearby hole similarly charged. The fall of rocks from these two holes buried the steam shovel and some of the gang of men working around it.(B) In September, 1909, in the Canal Zone, a steam shovel uncovered a misfired charge of dynamite. While the dynamite was being picked up the steam shovel continued working nearby. A spark from the shovel set fire to some loose dynamite spilled on the ground from the troken cartridges. This fire was transmitted to a hole which was being loaded close by and caused a premature explosion. One man was injured."

Nov 1, 1920

In December's marketing of 99.5 percent aluminum ingot, domestic producer pricing remained at 53$ per pound, while dealer quoting rose from 47.5¢ to 48.5¢. BORON Domestic production of boron minerals and chemicals reached an all-time high in 1977--1.4 million short tons valued at $236 million. Combined sales of the three California producers topped the 1976 level by 15 percent in quantity and 28 percent in value, a consequence of healthy demand in the glass and insulation industries. Unprecedented demand for boric acid as a flame retardant for cellulosic insulation stimulated producers to utilize fully all available capacity, thereby achieving a record output of 158,000 tons. One company increased output from its existing boric acid facilities and initiated production at another plant that historically had produced only sodium borates. A second company achieved a previously planned 25 percent plant expansion.

Jan 1, 1978

By Howard M. Stainer

Jan 1, 1963

By Howard M. Stainer

[Cover Page]

Jan 1, 1963

By N. A. Eilertsen

This report describes field investigations conducted in 1953 of two occurrences of manganese and a separate magnetic anomaly in the Southern manganese district of Aroostook County, vicinity of Houlton, Maine -the Pierce deposits, in Hammond Plantation Township; the Burnham anomaly, also in Hammond Plantation; and the Nickerson-Farm prospect in Hodgdon Township. The manganese occurs in a thinly laminated sedimentary rock containing manganiferous carbonate interlayered with fine-grained metamorphosed sediment, rich in chlorite or hematite. The surrounding rocks are mostly dark gray-green slates. Samples composited for metallurgical testing from the Pierce deposits and the Nickerson-Farm prospect assayed 9.0 to 12.3 percent of manganese. More than 90 percent of the manganese could be extracted with sulfuric acid, but in most instances 30 to 40 percent of the iron was also extracted. Leaching tests indicated that, after being reduced in a hydrogen stmosphere at 600° C., about 85 percent of the manganese could be selectively extracted by a solution of ammonia-ammonium carbonate with iron extraction of only 14 percent.

Jan 1, 1958

By D. E. Traut

The effect of various ion concentrations on uranium absorption from a sodium carbonate solution by a strong-base, anion resin was investigated by the Bureau of Mines in support of its objective to help assure an adequate uranium supply for future needs. The studies were conducted to improve the recovery of uranium from in situ leach solutions by ion exchange. The effects of carbonate, bicarbonate, chloride, and sulfate ions were examined. Relatively low (less than 5 g/l) concentrations of chloride, sulfate, and bicarbonate were found to be detrimental to the absorption of uranium. High (greater than 10 g/l) carbonate concentrations also adversely affected the uranium absorption. In addition, the effect of initial resin form was investigated in tests of the chloride, carbonate, and bicarbonate forms; resin form was shown to have no effect on the absorption of uranium.

Jan 1, 1979

By William L. Crentz

1. SALES PUBLICATIONS

Nov 1, 1949

By Claire C. Caruso, John M. Russo, Jennifer M. Schmit, Robert B. Dick, Edward M. Hitchcock

PURPOSE This report provides an integrative review of 52 recently published research reports that examine the associations between long working hours and illnesses, injuries, health behaviors, and performance. The report is restricted to a description of the findings and methods and is not intended as an exhaustive discussion of all important issues related to long working hours. Findings and methods are summarized as reported by the original authors, and the study methods are not critically evaluated for quality. SUMMARY In 16 of 22 studies addressing general health effects, overtime was associated with poorer perceived general health, increased injury rates, more illnesses, or increased mortality. One meta-analysis of long work hours suggested a possible weak relationship with preterm birth. Overtime was associated with unhealthy weight gain in two studies, increased alcohol use in two of three studies, increased smoking in one of two studies, and poorer neuropsychological test performance in one study. Some reports did not support this trend, finding no relationship between long work hours and leisure-time physical activity (two of three studies) and no relationship with drug abuse (one study). A pattern of deteriorating performance on psycho physiological tests as well as injuries while working long hours was observed across study findings, particularly with very long shifts and when 12-hour shifts combined with more than 40 hours of work a week. Four studies that focused on effects during extended shifts reported that the9thto 12th hours of work were associated with feelings of decreased alertness and increased fatigue, lower cognitive function, declines in vigilance on task measures, and increased injuries. Two studies examining physicians who worked very long shifts reported deterioration on various measures of cognitive performance. When 12-hour shifts combined with other work-related demands, a pattern of more adverse findings was detected across studies. Six studies examining 12-hour shifts combined with more than 40 hours of work per week reported increases in health complaints, deterioration in performance, or slower pace of work. Two studies com-paring 8- and 12-hour schedules during day and night shifts reported that 12-hour night shifts were associated with more physical fatigue, smoking, or alcohol use. Two studies examining start times for 12-hour shifts reported that decrements in alertness or more health complaints were associated with early 6:00 a.m. start times. One study examining 12-hour shifts in hot work environments reported a slower pace of work as compared with shorter shifts. Another study examining high workloads during 12-hour shifts showed increased discomfort and deterioration in performance as compared with shorter shifts. More definitive statements about differences between 8-hour and 12-hour shifts are difficult because of the inconsistencies in the types of work schedules examined across studies. Work schedules differed by the time of day (i.e., day, evening, night), fixed versus rotating schedules, speed of rotation, direction of rotation, number of hours worked per week, number of consecutive days worked, number of rest days, and number of weekends off. All of these factors could have interacted with overtime and influenced study results. Also, some studies did not report how many hours participants worked per week or other details about the work shifts, which complicated the assessment of their results. The many

Jan 4, 2004

By Edward J. Kansa

In a Bureau of Mines study, unsteady, spherically symmetric, one-dimensional, compressible-flow (finite sound speed) equations were solved numerically for a spherical deflagration propagating concentrically in a spherical vessel with Mach numbers ranging from 0.2 to 0.7; trajectory histories agree with the infinite-sound-speed theory developed by Perlee, Fuller, and Saul (PFS). A preliminary result of this study shows that flames propagating with speeds greater than 20 pct the speed of sound in the unburned gas mixture generate a complex history of aerodynamic waves distributed throughout the spherical vessel. Although the average pressure and flame radius agree with those predicted by the PFS models, the aerodynamic waves have a pronounced effect on the flame velocity, differing appreciably from that predicted by the PFS model.

Jan 1, 1976

Part Two of this report is based upon six working memoranda prepared during the first half of 1972 at an early stage in our work for the Bureau of Mines. This work presents preliminary performance estimates of baseband voice and narrowband through-the-earth electromagnetic communications systems of principal interest to the Bureau for operational/ emergency mine communications applications. The calculations were prepared to obtain early indications of the feasibility and governing parameters of such communications systems. They are based on limited, but pertinent, coal mine electromagnetic noise data acquired to-date by Bureau of Mines contractors; on theoretical signal-attenuation characteristics for two transmitter antenna types of present interest to the Bureau and on semi-empirical models which describe the intelligibility of voice communications as a function of the frequency variations of the signal-to-noise ratio across the voiceband. This work examines the cases of baseband voice and narrowband communications for uplink and downlink transmissions, for frequencies up to 3kHz. Downlink transmissions are via a horizontal wire antenna, and uplink transmissions via a vertical-axis loop antenna, for typical mine depths of 300, 600, and 1000 feet. Representative coal-mine overburden conductivities of 10-2 mhos/meter (moderate and common) and 10-1 mhos/ meter (high) were used; the former figure for both voice and narrowband calculations and the latter for narrowband calculations only. Examples of high, moderate, and low, surface and subsurface, harmonic and broadband-impulsive noise conditions were taken from NBS and Westinghouse (WGL) mine noise data, together with examples of high- and low-levels of ELF atmospheric noise taken from M.I.T. Lincoln Laboratory data. The effects of simple voice spectrum shaping techniques on the intelligibility of through-the-earth voice communications are examined, and indexes of intelligibility more broadly based than signal-to-noise ratio are discussed. Finally, a means of overcoming the affects of 60 Hz noise and its harmonics which are the largest contributors to typical audio frequency in-mine noise, is suggested. These feasibility calculations are not intended to serve as definitive and complete treatments, but as a starting point: to establish first-order estimates of the magnitude and variability of transmitter power requirements under different noise, overburden conductivity, and mine depth conditions; to identify relationships, conditions, or frequencies that are likely to limit or enhance system performance; to reveal items requiring further investigation and data still required; and to suggest practical methods for optimizing system performance. These objectives were met by the calculations. Simple experiments to support these calculations can and should be carried out; together with more detailed investigations of specific modulation, coding, noise-suppression, voice-compression and signal-conditioning techniques, aimed at producing through-the-earth operational/emergency mine-communication systems that are not only effective, but practical and economically sound.

Jan 1, 1974