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By L. C. IlsLey

[The last previous Bureau of Mines publication relative to details of permissible methane detectors (Bulletin 331, published in 1930) describes detectors of four different types, namely flame, combustion, catalytic, and a combination Wheatstone-bridge axed catalytic type in which catalytic action at the surface of a platinum filament when in methane causes a change in the temperature and resistance of the filament, thus unbalancing the bridge circuit and giving a reading proportional to the methane concentration. Three detectors of the latter type have been approved since 1933. A brief description of each follows: U. C. C. Detector Approved No. 902, covering the U. C. C. indicating detector, as described in Bulletin 331, was entered January 27, 1330, to cover important chances in design that permit checking; the calibration of the detector at any time, whether in gas or fresh air. Essential features of the detector are shown in figure 1.]

Jan 1, 1937

By R. P. Adams

Because of the extreme interest in materials with high melting temperatures and the advantages offered over the powder route for making high-density material, arc-melting and centrifugal-casting methods were investigated for preparing shapes of hafnium carbide with and without excess carbon. Highly satisfactory equipment was constructed and efficient operating procedures were established. Also, methods for preparing consumable electrodes and shrink-tolerant graphite molds were developed. Although crack-free hafnium carbide (6.3 weight-percent carbon) shapes were not made, coherent castings containing 9 to 13.5 weight-percent carbon were produced; the same compositions were shown to be resistant to thermal shock. Selected physical and chemical tests were performed on castings chosen for investigation by chemical and nondestructive inspection techniques. Electrical conductivity and thermal expansion measurements were made. Measurable oxidation of all the compositions studied was observed to start between 500° and 600° C. Attack by nitrogen, however, did not occur until temperatures exceeded 2,000° C. A linear relationship of the logarithm of the diamond pyramid hardness to the temperature was noted. Considerable scatter of the bend-rupture strengths at room temperature and of the tensile strengths up to 2,000° C was found. However, at the latter temperature and above, a definite relationship of strength to temperature was observed and some ductility was noted.

Jan 1, 1968

By Ralph L. Rinehart, Wils L. Cooley

This paper summarizes recent experiments with grounding systems. Problems and potential hazards related to in-mine grounding systems are discussed. The monitoring of trailing cable ground conductors and testing of commercially available ground monitors are discussed.

Jan 1, 1975

By Roger L. King

The Bureau of Mines has developed probes to be used in emergency mine rescue operations by being lowered through a borehole drilled into an underground mine. Various probes can provide two-way voice communication with trapped miners, continuous mine atmosphere monitoring, temperature indication, and television searching capability. At present, an infrared imaging probe is being developed for "seeing" through coal smoke.

Jan 1, 1976

By M. C. Irani, Maurice Deul, M. G. Zabetakis, T. G. Bobick

This survey was conducted to determine the magnitude of the methane emission and control problem in U.S. bituminous coal mines. The resultant data indicate that the emission rate for any given coalbed depends primarily on the coal production rate and on mine depth, as well as on the nature of the coalbed and the surrounding strata. An excellent correlation was found between (1) the methane emission rate and (2) the product of coal production rate and mine depth for the mines in the Pittsburgh, Pocahontas Nos. 3 and 4, and the Illinois Nos. 5 and 6 coalbeds. The highest total emission rates found in U.S. bituminous coal mines were as follows, in million cubic feet per day: Monongalia County, W. Va., 39; Marion County, W. Va., 30.4; McDowell County, W. Va., 13.1; Washington County, Pa., 11.9; Greene County, Pa., 11.4; Buchanan County, Va., 21.6; Jefferson County, Ala., 10.3; and Franklin County, Ill., 6.6.

Jan 1, 1972

By Ivan F. Avery

The design productive capacity of natural-gasoline and cycling plants in the United States on January 1, 1960, was 54.6 million gallons per day, according to the Bureau of Mines biennial survey. This represents an increase of 5.8 million gallons per day during the 2-year period since the last survey. The major increases occurred in Louisiana, Oklahoma, New Mexico and Texas. In Utah, natural gasoline capacity was reported for the first tine at 320 thousand gallons per day as of January 1, 1960. The total number of plants increased from 584 on January 1, 1958, to 596 on January 1, 1960. However, the operating plants decreased from 558 to 555 in the same period.

Jan 1, 1961

By J. G. Donaldson

The Bureau of Mines investigated the formation of boron and boron-carbide coatings by vapor-phase reactions. Optimum parameters were determined for hydrogen reduction of boron trichloride and for the fonnation of boron-carbide coatings on graphite by reaction with the depositing boron. At 1,300° C, about 85 percent of the boron was deposited. Tungsten substrates did not react with the boron deposit; other substrates reacted to various extents. The hydrogen reduction of boron tribromide was briefly investigated. Boron carbide was deposited at 1,300° C by adding methane to the boron trichloride-hydrogen feed gas. The chemical composition of the vapor-deposited boron carbide approximated B4C. A method of etching B4C was developed to study its microstructure. When boron was deposited on graphite at 1,500° C, very hard, uniform, strongly adherent coatings of B4C were formed that might be useful in rocket nozzle applications.

Jan 1, 1968

By Charles L. Kimbell

World political events that occurred subsequent to yearend 1990, but that bear heavily on the global mineral industry, have been of such importance that they cannot be disregaded, and certainly they contribute to any type of "outlook." However, to write of them simply as "forecasts" in an "outlook" section of this study would be to unjustly pretend to status as prophets. Thus, this section covers events that have occurred not as predictions but rather as history. Despite the end of the cold war, the world remained fractionated, at least from the limited perspective of its mineral industry. The fractionation was not so much the result of adversarial politics between countries and groups of countries, although to be sure, such conflicts had not disappeared. Rather, the fractionation was in the widely divergent patterns of performance that resulted from the diverse conditions and problems facing the different countries and country groups.

Jan 1, 1993

By H. H. Schrenk, F. E. Griffith

"The increase in tunneling operations that requires working under pressures greater than that of ordinary atmosphere has raised the question of the use and possible limitations of respiratory protective devices under such unusual conditions. As little, if any, information is available, there is need for a comprehensive study of this subject before specific recommendations can be made. In the absence of such data it seems desirable to make a few preliminary observations regarding the problems associated with wearing respiratory protective devices under increased air pressures.Two distinct problems must be considered--the mechanics of the apparatus used under such conditions and the physiological effects of increased pressures on wearers of respiratory apparatus. This report is confined to the use of oxygen breathing-apparatus and gas masks under pressure.ACKNOWLEDGMENTSThe data presented were obtained at the Queens Midtown Tunnel under construction at the east end of 42d Street, New York City, during a study of compressed-air illness conducted by the Bureau of Mines in cooperation with the United States Public Health. Service and the New York City Tunnel Authority.Grateful acknowledgment for cooperation and the use of facilities is made to Dr. R. R. Sayers and his associates, particularly Dr. J. W. Crosson (who acted as observer during the oxygen breathing apparatus tests), of the Division of Industrial Hyiene, National Institute of Health; to the Port of New York Authority, through Dr. Edward Levy; end to the contractors, through Doctor Emery."

Jan 1, 1940

By W. D. Dietzman

This Bureau of Mines report presents a continuation of statistics pertaining to distribution of petroleum reservoirs (or fields), wells, and production by depth and producing rate classification in the United States. These statistics show the change that has occurred since results of a similar study were published by the Bureau of Mines in 1967. Data are presented in tabular form by State for the 18 principal oil-producing States and by subdivision for the two larges t oil-producing States, Texas and Louisiana, Tabular summations and graphical illustrations are presented for the Nation. The data are classified by 4-barrel-of-oil-per-day rate increments up to 36 barrels and one increment of greater than 36 barrels of oil per day and by 2,000-foot depth increments up to 8,000 feet and one depth increment of greater than 8,000 feet. The overall average producing rates for States and the Nation have been published for many years; although such rates are useful, they are very general descriptions of producibility. A breakdown of production, wells, and reservoirs by various depths and rates and by State or by State subdivision provides a more detailed description of producibility.

Jan 1, 1976

By V. E. Erwin, W. W. Adams

"Production of explosives for industrial use in,the United States during 1934 continued the upward trend begun in 1933 from the low-level output of 1932, and the output in 1934 was only slightly less than in 1931.Reports to the United Stated Bureau of Mines from companies engaged in the manufacture of industrial explosives showed that the quantity of explosives manufactured in the United States and sold during 1934 for use within the various States was 314,767,922 pounds - 23 percent more than in 1931.Production during 1934 included 39,207,845 pounds of permissible explosives 5 206,625,027 pounds of high explosives other than permissibles, and,68,935,050 pounds of black blasting powder of which 37,192,700 pounds were in granular form and 31,742,350 pounds in pellet form. These figures represent an increase over 1933 of 15.6 percent for permissible explosives, 30.9 percent for other high explosive, and 7.4 percent for black powder.Coal-mining operations were the chief consumers of permissible explosives; 99 percent of the total output in 1934 was used, in coal mines. The proportion used by bituminous mines was 59 percent and by anthracite mines 40 percent. Coal mining was likewise the principal consumer of black blasting powder, taking 88 percent of the total sales during 1934; of this proportion, bituminous mines received 78 percent and anthracite mines between 9 and 10 percent. Consumers of high explosives other than permissibles were more varied; the reports showed that 11 percent of the total quantity sold was for coal mining, 22 percent for metal mining, 17 percent for quarrying and nonmetallic-mineral mining, 46 percent for railway and other construction work, and 4 percent for all other purposes."

Oct 1, 1935

By C. H. Elder

Coal degasification boreholes drilled from the surface have been success-fully hydraulically stimulated to increase the flow of gas from the coal. This Bureau of Mines report describes the hydraulic stimulation procedure for a coalbed, the equipment required, and design criteria for the treatment. Three examples of stimulation treatment show from fivefold to twentyfold increases in gas production. The tests were conducted in the Pocahontas No. 3 coalbed, Buchanan County, Va., the Pittsburgh coalbed, Washington County, Pa., and the Mary Lee coalbed, Jefferson County, Ala. Two sites where the coal was hydraulically stimulated and exposed by subsequent mining show no adverse effect on mining operations through the treated zones. The induced vertical partings were confined to the coalbed and did not in any way affect either roof or floor rock.

Jan 1, 1975

By R. Pakalnis, Richard P. Curtin, Lewis A. Martin

Instrumented cable bolts developed at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health were used in conjunction with existing ground control to monitor rock mass loads at various field sites (FMC Granger, Getchell, Meikle, SSX, K-2, and Stillwater). Axial and shear loads were determined by strain gauges to levels of instrument accuracy of ±5 N or ±5 microstrain as these loads were transferred to the instrumented cable bolts. These gauges were 12.5 mm long and embedded into are manufactured king wire that replaced the conventional king wire. Cable bolt performance, quality of grout, and installation techniques were also assessed. By using instrumented cables, a mine operator can determine axial load along the cable at predefined gauge locations. By monitoring load on and displacement of the rock mass, more effective ground support can be selected and installed, which will lead to safer working conditions for miners.

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

APPENDIX E REFUGE CHAMBER LEAKAGE ANALYSIS Variables p 0 = pressure outside of chamber (psi) p = pressure inside of chamber (psi) i q = leakage flow rate (cfm) Q= total leakage (cu ft. ) V = chamber volume (cu. ft. ) t= time (minutes) p= nominal atmospheric reference pressure (14.7 psi) A= chamber leakage coefficient (cfm/psi)

Jan 1, 1976

By Irving Hartmann

Modern mechanized mining with high-speed machines, multiple-entry systems, multiple blasting, high-velocity air currents, and rapid haulage has brought many economic benefits and has on the whole enhanced safety in the coal-mining industry. It has, however, also introduced some added hazards, the control of which requires concerted effort and ingenuity. Mechanized mining has greatly increased the production and dissemination of fine coal seam or in mine entries. Use of high-speed machines has increased the probability of formation of incendive sparks, which are produced by frictional contact between moving metals and certain mineral substances in the coal seam or in the adjoining rock strata. In gassy seams rapid extraction of coal has increased the rate of gas evolution. These facts have made more urgent the need of preventing the ignition of coal dust and the development of widespread mine explosions. The ignition hazard can be controlled best by eliminating all potential igniting sources and by careful attention to ventilation designed to prevent accumulation of gas capable of triggering a coal-dust explosion. Frictional spark ignition by mining machines and suggested safeguards are discussed in a recent publication. Extensive research and long experience have shown conclusively that the propagation of coal-dust flames can be arrested and the development of widespread explosions prevented by properly applied, generalized rock dusting.

Jan 1, 1956

By W. W. Weller

Low-temperature heat capacities of scandium sesquioxide (Sc203) and a mixture of cerium sesquioxide (Ce203) and cerium dioxide (CeO2) were measured over the temperature range from 50° to 298° K. The entropy of scandium sesquioxide at 298.15° K was evaluated directly as S°298.15 = 18.4 ± 0.1 cal/deg mole. That of cerium sesquioxide was extracted by combining the heat-capacity data for the mixture with those for pure cerium dioxide; the result was S298.15 36.0 ± 1.0 cal/deg mole.

Jan 1, 1963

By Paul W. McGann

THE MINERAL INDUSTRIES had a near-record year in 1950, as rising industrial activity in general, greatly accentuated by the outbreak of hostilities in Korea in midyear, called forth increasing supplies of mineral fuels and raw materials. The aggregate value of mineral production was second only to that in 1948, and the aggregate physical volume was exceeded only in 1948 and 1947. Lower coal production accounted for the failure to surpass these earlier years. Growth of production was fairly constant throughout the year, especially for crude petroleum; its physical output for the year as a whole exceeded that of 1949 by 7 percent. According to Federal Reserve Board indexes, other relative gains were 16 percent for coal, 9 percent for fuels in general, and 17 percent for metals. The increase for mining in general was of the order of 10 percent. This was not quite as large as the general increase in industrial production but clearly reflected the total-industrial trend (see fig. 1).

Jan 1, 1953

By James H. Russell

The Bureau of Mines, U.S. Department of the Interior, in cooperation with the Department of Energy, has attempted to increase the activity of nickel catalysts for converting synthesis gas, derived from coal, to a substitute natural gas. This report describes the effects of low-level additions of B, Ca, Ce, Co, Mn, Mo, Pd, Re, Ti, Y, Zn, and Zr on the methanation activity of Raney nickel. The methanation rate at 320° C and the resistance to poisoning by 2 ppm H2S were used to compare catalysts. The effects of the additions were small, and the experimental variances were large, necessitating the use of statistical methods to identify significant effects. Co, Ti, Y, and Zn improved the resistance to H2S poisoning, but only Co improved the methanation rate In some individual catalysts containing Ca, Mo, or Mn, both the methanation rate and resistance to H2S poisoning were improved.

Jan 1, 1980

Provide better ventilation for mines by reducing air leakage around stoppings. Approach Most stoppings are constructed of concrete blocks and trowelled-on mortar and are not very airtight. Bureau of Mines research has shown that brushing on modified mortar containing fiberglass and/or other additives, that enhance strength and adhesion, minimizes air leakage around and through the stoppings. Airtightness is an important factor in building stoppings since an airtight stopping will provide for more efficient ventilation airflow and more cost-efficient use of the mine's ventilation system. How the New Technique Works After broken floor and rib material is removed, the stop-ping faces are covered with one or two coats of modified

Jan 1, 1982

By James P. Rider, Jay F. Colinet

The National Institute for Occupational Safety and Health (NIOSH) has conducted benchmarking surveys at longwall operations across the country to identify current operating practices and the types of controls being used. Gravimetric and instantaneous dust sampling was completed to quantify dust generation from major sources and determine the relative effectiveness of the different control technologies. Results from the underground dust surveys will be presented as an update on longwall dust control technology and operating practices.