Search Documents

By C. A. Komar

The Bureau of Mines conducted experiments on one synthetic and three natural sandstone samples to investigate the effects of acoustic energy on the flow of brine in porous media. Ultrasonic energy at a frequency of 20 kc per second and an intensity of 55 watts per cm2 was irradiated in the direction of the fluid flow and in the opposite direction for distances of 1/2 and 2 inches between the vibrating device and the sample face and under conditions of suppressed and nonsuppressed cavitation. Forty tests were conducted: 32 with a pressure differential of 0.64 psi across the samples, 2 with 5 psi, and 6 with 15 psi. Acoustic waves altered the rate of flow of the brine through the samples, but this effect was observed only at low differential pressures and from a practical point of view was insignificant. As a result of irradiation, however, the samples exhibited reduced permeability. This reduction was probably caused by the shifting of solid particles dislodged by the acoustic waves.

Jan 1, 1967

By R. C. Hickman

Manganiferous breccia formations on three properties were prospected by the Bureau of Mines from January to November 1954 in Johnson County, Tenn. The prospecting consisted of diamond drilling, trenching, shaft sinking, and crosscutting. The results of the exploratory work show the manganiferous material to be low-grade, with little vertical extension. The manuscript on this report was completed February 1955. LOCATION The prospects are in Johnson County, Tenn. (fig. 1), within a radius of 12 miles from Mountain City. The nearest railroad terminal is Damascus, Va., 14 miles from Mountain City.

Jan 1, 1956

By S. H. Lorain

This paper is one of a series on mining and milling method and costs being published by the United States Bureau of Mines. The Golden Messenger mine, operated by the United Gold Mines Corporation, is in the York-Confederate Gulch mining region in Luis and Clark County, Mont., 22 miles northeast of the city limits of Helena and about 1 mile north of the town of York. It is the first operation to exploit successfully the low-grade ores of the York-Confederate Gulch area. The unusual vein structure presents some mining problems that have been solved in ail interesting manner.

Jan 1, 1937

By Phillip W. Holland

The U.S. Bureau of Mines has developed a mass spectrometer method for determining helium in the parts-per-million to 10% range to an accuracy of ± 1%. The method employs a mass spectrometer, an inlet system utilizing a chromatographic gas-sampling valve, and an activated coconut charcoal trap cooled with liquid nitrogen. Gravimetrically prepared standards of helium in nitrogen were used to demonstrate the linearity of the method over the concentration range of 10 ppm to 10.66% helium.

Jan 1, 2010

By Seth C. Schaefer

The Bureau of Mines has determined the standard Gibbs energies (AGf°) of CoS1.035 (cobalt sulfide) and Ni2.515S2 (nickel sulfide) with high-temperature galvanic cells using stabilized Zr02 (zirconia) as the electrolyte. Potential measurements were obtained for the cell Pt, CoS1.035, CoO, S02(g, 1 atm)//Zr02//02(g, 0.0114 atm), Pt, with the overall cell reaction C0S1.035(c) + 1.535 02(g, 0.0114 atm) = CoO(c) + 1.035 S02(g)¬ These results, combined with the best available data for ?Gf° of CoO and S02 from the literature, give the standard Gibbs energy of formation of CoS1.035 for the reaction Co(c) + 0 5175 S2(g) = CoS1.035(c) ?Gf° = -38.890 + 18.87 x 10-3T ± 0.185 kcal/mole (866.0 - 1,104.9 K), where temperature (T) is expressed in kelvins. Similar measurements were obtained for the cell Pt, N12.515S2, NiO, S02(g, 1 atm)//Zr02//02(g, 0.0122 atm), Pt, with the overall cell reaction Ni2.515S2(c) + 3.2575 02(g, 0.0122 atm) = 2.515 NiO(c) + 2 S02(g). Combination of these results with data for ?Gfo of NiO and S02 from the literature yields the standard Gibbs energy of formation of Ni2.515S2 for the reaction 2.515 Ni(c) + S2(g) = Ni2.S1SS2(c) ?Gf° -65.377 + 24.67 x 10-3T ± 0.541 kcal/mole (968.6 -1,053.7 K).

Jan 1, 1981

By F. W. Lane

Some months ago the Bureau of Mines began research of a fundamental character on sulphur in petroleum. In the course of this work, the usual qualitative test for sulphur in organic compounds1 was applied to certain oils that were believed to contain approximately 0.5 percent sulphur. No sulphur was found, and, as a check on the qualitative test, the oils were subjected to quantitative determination of this element by the oxygen-bomb method.2 The sulphur content of the oils ranged from 0.10 per cent to 0.50 per cent. This experience led to further trial of the qualitative test for organic sulphur, both on the oils mentioned above, and on common sulphur-containing organic substances. No difficulty was experienced in detecting the element in the latter, but with the petroleum oils the test, as usually performed, could not be relied upon to detect less than 0.60 per cent of sulphur consistently. The use of mechanically polished pure sheet copper for the detection of free sulphur, hydrogen sulphide, and perhaps other sulphur compounds has been recommended.3

Jan 1, 1927

By Richard J. Mainiero, Marcia L. Harris

The New York State Department of Transportation recently commenced highway widening and drainage improvement projects in Clarence and Amherst, NY. Drainage improvements including the installation of storm sewer lines required excavation to a depth of 2.5 m (8.2 ft). In September 2002, NYSDOT stopped further blasting when 800 ppm CO was detected in the basement of a house near the blasting site. At the insistence of NYSDOT, the general contractor developed a new blast plan with the assistance of an environmental consultant. The plan provided for the installation of multi-gas monitors in buildings of special concern and/or with basements and residential type CO monitors in all other buildings within 100m (330 ft) of the blast. The multi-gas monitors would be remotely monitored. The plan provided action levels which would ensure public safety. The blast design was also modified to allow for better venting of CO. Blasts were limited to 20 ft lengths. The overburden was to be removed from the rock and blasting mats put in place to prevent flyrock. Approximately twenty feet of trench adjacent to the blast was left open to allow ground movement and gas release. The use of CO monitors was effective to alert occupants of a building to the presence of CO. The most effective appeared to be the residential type CO alarms with digital readouts. They were simple and easy to use and allowed the public to participate in the process. False alarms were repeatedly received with the more sophisticated instrumentation. Residential type CO monitors are preferable to warn people near blast sites. More sophisticated instrumentation should be avoided unless personnel are experienced in its use. A general overview of the blasting and monitoring is presented and discussed. The use and effectiveness of residential type CO monitors and multi-gas monitors are discussed.

By Floyd G. Anderson

The Federal Bureau of Mines promotes the use of safe and effective dust-collecting devices for rock drilling in coal mines. To insure that such devices are available to the coal-mining industry, the Bureau issues certificates of performance for dust-collecting systems and certificates of approval for dust collectors and rock drills or other mining equipment with integral dust-collecting systems that meet the requirements of an established Schedule.4/ Investigations are conducted under the provisions of the current revision of this Schedule by engineers of the Branch of Health Research. This circular describes briefly the requirements and procedure for obtaining certificates of performance or approval and lists equipment that has been certified as permissible under Schedule 25 or its revisions as of January 31, 1961. The names and addresses of companies to which certificates have been issued are listed alphabetically at the end of this circular.

Jan 1, 1961

By Philip W. Holland

The Bureau of Mines has developed a trace helium analyzer for deter-mining helium-4 in the parts-per-billion range. The instrument is used for analyzing pure gases, laboratory-prepared standards, and atmospher-ic samples. Accuracy at the 95-pct confidence level in the 50-to 20,000-ppb range is within ±2 ppb or ±0.4 pct, whichever is greater. The minimum detectable helium-4 concentration is calculated to be 5 ppb. The analyzer consists of a modified helium leak-detector mass spec-trometer, a laboratory-built sample inlet system, and a liquid-nitrogen-cooled charcoal trap. A programmable integrator and event-control module make automatic operation possible. The portability of the analyzer allows it to be used in the field.

Jan 1, 1984

By Eric R. Bauer

This U.S. Bureau of Mines study was conducted to gain a basis for recommending methods to predict and prevent the occurrence of cutter roof failure, a common ground control problem in mines of the Northern Appalachian Coal Basin. This was accomplished by determining the geologic and engineering factors responsible for cutter development at six mines affected by cutter roof failure. Three distinct factors were found to be initiators of cutter roof failure: (1) high horizontal roof stress, (2) surface topographic variations, and (3) geologic anomalies. Effective control of cutter roof was obtained through improved bolting techniques, entry and mine reorientation, and entry and pillar size modifications, but only when selected based on the actual cause of failure.

Jan 1, 1990

By P. M. Brown

The Bureau of Mines is investigating a dewatering technique for coal-clay waste that uses a flocculant, polyethylene oxide (PEO). This flocculant forms strong stable flocs that can be dewatered on a static screen. A field test unit (FTU) using this technique was operated at approximately 400 gal/min, using a waste stream from the flotation circuit of a coal preparation plant. Consolidated coal-clay material con-taining 55 to 60 pct solids was produced when the flotation circuit slurries of 2.7 to 8 pct solids were treated with 0.1 to 0.3 Ib PEO per ton of solids. The FTU was also operated at 64.5 and 87.5 gal/min using a portion of the underflow slurry from the preparation plant's thickener. Consolidated coal-clay material containing 55 to 60 pct solids was produced when the thickener underflow slurries of 19 to 24 pct solids were treated with 0.08 to 0.2 Ib PEO per ton of solids. PED-treated materials continued to dewater when placed in a pit.

Jan 1, 1983

By Charles Seitz

The Bureau of Mines has modified its parts-per-billion helium-4 analyzer to improve the analytical capabilities of the instrument. The modifications resulted in the following improvements: (1) The analytical precision of the instrument for 10 consecutive analyses was improved to ±1 ppb at the 5,000-ppb helium-4 level, (2) the helium-4 sensitivity was increased almost tenfold, and (3) the minimum detectable limit for helium-4 was improved to 0.5 ppb. The modifications made to improve the instrument included replacing the ion-source control circuit with a direct-current solid-state design, controlling the temperature of the ion source, stabilizing and reducing the pumping rate of the vacuum system, and optimizing peak integration.

Jan 1, 1986

By Herbert R. Babitzke

The purpose of this investigation was to optimize the high-temperature properties of columbium and tantalum. Columbium and tantalum were combined with selected alloying elements to achieve solid solution and dispersion strengthening. Fifty-six alloys were evaluated to determine their formability, hardness, strength at elevated temperatures, and oxidation resistance. The following six alloys showed high-temperature strength: [Cb-15Hf-5W-2Zr-4Al-4Ti-2N Cb-15Hf -5W-5Zr Cb-15.3Ti-4.1Zr-13.7Hf Ta-20Hf-4Al Ta-30Hf-4Al Ta-20Hf-5W-4Al] At 1,200° C, the columbium alloys had strength values of 40,000 psi or greater, and the tantalum alloys had strength values from 50,000 to 58,000 psi. For a 2-hour test period at 1,000° C, weight gains of only 9 and 8 mg/cm2, respectively, were observed on oxidation testing of two alloys, Cb-15Hf-5W-2Zr-4Al-4Ti-2N and Ta-20Hf-5W-4Al.

Jan 1, 1968

By L. L. Rethi

The U.S. Bureau of Mines summarized injury data for independent contractor employees working at all locations of coal and metal-nonmetal mines from 1983 through 1990. During the eight years, the greatest contrast in degree of injury between independent contractor and operator employees was in fatalities. From 1983 through 1990, there were 132 independent contractor employee fatalities in the mining industry. In 1988 though, independent contractor employees accounted for nearly one-fourth of all mining fatalities. The fatality incidence rates of independent contractors were consistently higher than those of operators during the eight years. For instance, in 1990, the contractors' rate was twice that of operator employees in coalmining and nearly five times that of operators in metal-nonmetal mining. Three other salient facts highlight the independent contractor employees' fatality injury data during these years. First, 82% of the independent contractor employee fatalities occurred at surface locations. Second, two job classifications?truck driver and equipment operator?represented 37% of the fatalities throughout the 8-year period. And finally, four accident classifications?powered haulage, slips and falls, machinery, and electrical?accounted for 71% of all independent contractor employee fatalities.

Jan 1, 1993

This volume summarizes the contract work performed over a nine-month period by Westinghouse Electric Corporation on a Cost Plus Fixed Fee Contract for the Department of Interior's Bureau of Mines. The contract has been extended primarily to carry out improvements recommended for equipment produced under the contract for communicating with and locating trapped miners. These improvements will enhance the performance and utility of this equipment for operational use in actual mine emergencies. An additional complete set of the equipment will also he furnished to the Bureau under this extension. The work of the basic contract was to design, produce and test hardware in accordance with the Westinghouse response to a Bureau of Mines Request for Proposal which was based technically on recommendations of a study performed for the Bureau by the National Academy of Engineering (NAE). The NAE study made suggestions for new equipment in three areas of need:

Jan 1, 1971

By G. R. Hopkins

[Apparent progress in fuel economy at petroleum refineries, as measured by the average amount of .seat units required to refine a barrel of crude oil, received a set-back in 1935, when the average rose to 562,00 B. t. u., compared with 562,000 B.t.u. in 1937 (see fig. l). The primary factor in the rise in average heat requirement's per barrel of crude oil refined in 1938 wan the decline in total runs to Invariably the average requirement increases when crude ins to stills decline, and vice versa. In other words, annual gains in fuel efficiency at refineries arc masked by the degree to which the capacity is utilized. Additional crude runs give lower average e heat requirements in two ways - first, because they are mane with the c expenditure of comparatively small amounts of auxiliary heat, and, second, because the additional runs generally represent simple topping operations. In 1938 crude runs, to stills declined 1.6 percent (from 1,183,440,000 barrels in 1937 to 1,165,015,000 barrels in 1938), but the total heat consumption declined only 0.4 percent, or from 663,866 billion B. t. u. in 1777 to 660, 56 billion in 1938 .]

Jan 1, 1939

By G. R. Hopkins

[Apparent progress in economy at petroleum refineries, as measured by the average amount of hest units required to refine a barrel or crude oil, received a set-back in 1938, when the average rose to 567,000 B. t. u., compared with 562,000 B. t. u. in 1937 (see fig. 1). The primary factor in the rise in average heat requirement's per barrel of crude oil refined in 1938 was the decline in total runs to Invariably the average requirement increases when crude inn to stills decline, and vice versa. In other words, annual gains in fuel efficiency at refineries are masked by the degree to which the capacity is utilized. Additional crude runs give lower average heat requirements in two grays first, because they are mane with the expenditure of cc-comparatively small amounts s of auxiliary heat, and, second, because additional runs generally represent simple topping operations. In 1938 crude runs to stills declined 1.6 percent (from 1,183,440,000 barrels in 1937 to 1,165,015,000 barrels in 1938), but the total heat consumption declined only 0.4 percent, or from. 663,866 billion B. t. u. in 1777 to 660, 56 billion in 1938.]

Jan 1, 1939

By V. A. Marple, K. L. Rubow, B. A. Olson

"A virtual impactor personal aerosol sampler (VIPAS) bas been developed for use in diesel-equipped mines to collect size-separated samples or diesel exhaust and mine dust particles in the respirable size range. This sampler consists or three stages: a 10-mm cyclone, a 0.8- µm cutpoint virtual impactor and two filter cassettes. The large non-respirable particles are removed in a 10-mm cyclone. The respirable particles from the cyclone pass through a 0.8- µm cutpoint virtual impactor with the particles larger than and smaller than 0.8 JI.ID (mine dust and diesel exhaust particles, respectively) collected on two 37-mm filter cassettes. The sampling How rate is 2 L/min so as to be compatible with the standard respirable dust sampler and personal sampling pumps. INTRODUCTIONThe mining industry has been increasing its use of diesel-powered equipment in underground mines, especially in coal mines. With this increased usage has come an increased concern regarding the health effects associated with inhaling diesel exhaust particles since they are in the respirable particulate size range. A Mine Safety and Health Administration (MSHA) advisory committee directed MSHA to develop a sampling protocol for diesel exhaust particles to assess worker exposure (MSHA, 1988). In addition, the National Institute for Occupational Safety and Health (NIOSH) has recommended that ""whole diesel exhaust be regarded as a potential occupational carcinogen as defined in the Cancer Policy of Occupational Safety and Health Administration"" (NIOSH, 1988).Past work, with cascade impactors in both the laboratory and in underground coal mine studies, has shown that the diesel exhaust particles are primarily in the less than 0.8 µm aerodynamic diameter size range whereas the coal dust particles are primarily greater than 0.8 µm (Marple et al., 1986; Cantrell, 1987; Rubow and Marple, 1988; Rubow et al., 1990a, b; Cantrell and Rubow, 1991). This work has been jointly performed by the University of Minnesota and Bureau of Mines researchers over the last 8 years. Typical particle size distributions for a diesel-equipped coal mine and an all electric coal mine are shown in Figure l. Note that the particles in the < 0.8-µ.m mode are the diesel exhaust particles (seen only in diesel-powered mines) and the particles in the > 0.8-µ.m mode are coal particles (seen in both the electric-powered and diesel-powered coal mines). Chemical mass balance analysis was also performed on these two size fractions to determine the degree of particle cross-contamination in the two modes. This analysis showed less than 10% cross-contamination, i.e., in coal mines Jess than 10% of the diesel exhaust particulate was collected in the coarse fraction and Jess than 10% of the mine dust was collected in the fine fraction (Cantrell, 1987; Rubow et al., 1990a)."

Dec 1, 1996

By K. C. Dean

Horizontal and vertical air classification systems were tested individually and in simulated tandem use for the recovery of ferrous and nonferrous metals and of other noncombustible and combustible products from shredded urban refuse. The horizontal air system with a larger tonnage throughput was used to obtain preliminary separations, and a smaller capacity vertical system was used as a cleaning device. Air elutriation, magnetic separation, and screening of shredded minus 6-inch municipal refuse recovered 92 percent of the metal in a relatively clean iron product contaminated only by adhering coatings or entrapped materials, recovered 97 percent of the combustibles in a 97-percent combustible product, and rejected 88 percent of the nonmetal noncombustibles. Cleaning of the preliminary combustible fraction produced a 98-percent paper product while rejecting other combustibles (plastics, rubber, textiles, etc.) into a 94-percent combustible product. Retreatment of the preliminary noncombustible fraction produced a relatively clean glass product.

Jan 1, 1971

By Jos. R. Guiteras

The present discussion first presents data to justify the fireproofing of mine shafts. This is followed by a brief outline of fireproofing methods with examples from practice. A summary of authoritative recommendations on fire prevention concludes the discussion. Acknowledgment is made to D. J. Parker, district engineer, Mine Safety Station, Salt Lake City, Utah, for his valuable criticism of the paper. Fireproofing a mine shaft implies lining the shaft with fireproof material or rendering fireproof the material already composing the shaft lining. A brief study of the part mine shafts and shaft stations have played in disastrous end tragic underground fires furnishes convincing evidence that every possible effort to make all mine shafts fireproof is amply justified. The fire hazard in coal minus obviously is much greater than in metal mines. In this discussion the point of views is mainly that of the metal miner; it is tine opinion of the writer that all fires in metal mines are preventable.

Jan 1, 1939