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By T. W. Hunter

THE TOTAL production of energy in the United States in 1954 decreased 4.6 percent below 1953. The production of coal continued to decline, and the production of crude oil decreased for the first time since 1949. These decreases were partly offset by an increase in the production of natural gas. The total energy production of 35,365 trillion B. t. u. in 1954 was the lowest since 1950. [ ] This drop in energy production was consistent with the 1.1-percent decline in gross national product during the year-from 364.5 billion dollars in 1953 to 360.5 billion in 1954.

Jan 1, 1958

By J. Weinberg

This Bureau of Mines report presents data on the changes in the use of steel in motor vehicles over the past 35 yr. Sources of supply of steel for the automotive sector have shifted from almost all domestic in the 1950's to about 50% domestic and 50% foreign in the 1980's. Downsizing, design changes, and substitution of lighter weight materials to achieve energy efficiency also contributed to the market loss of the domestic steel industry. Although plastics and aluminum have displaced some steel in motor vehicles over the years, heavy low-carbon steel is now being replaced most rapidly by lightweight high-strength steel. If the percent of domestic steel used in motor vehicles had not declined since 1950, domestic industry would have supplied 9.3 million more short tons of steel than it supplied in 1985. Downsizing and design changes accounted for 43% of the loss; steel imports, 32%; and substitution of plastics and aluminum, 25%. In 1985, the total value of market share lost by U.S. steel producers was $5.1 billion, of which $1.6 billion was lost to foreign steel producers and automobile manufacturers. Through aggressive marketing and increased efficiency, however, the domestic steel industry may be able to recapture some lost markets, as applications for high-strength steels expand, and as foreign-owned automotive plants in the United States provide fresh sales opportunities.

Jan 1, 1988

By Tobias W. Goodman

The U.S. Bureau of Mines used a contact drilling strategy with short-collared assemblies in order to rotary drill long horizontal methane drainage holes in the Beckley Coalbed near Glen Daniel, WV. By decreasing the thrust, and increasing the rotation of the drill bit when in contact with the roof and floor rock, assemblies with 1-ft (0.3-m), 10-ft (3- m), and 144 (43-m) long collars were made in deflect and stay in the coalbed. Successful application of this procedure resulted in holes drilled full length in coal with the original assembly including bit. The test assemblies deflected away from the original bearings of the holes during drilling and arced. Four holes were drilled to depths ranging from 478 ft (145.7 m) before the strategy was developed, to 4,034 ft (1,230 m) when the strategy was applied. Total length of the holes in coal was 8,590 ft (2,618 m). After 577 days the total methane captured by the holes was 221,600,000 ft? (6,276,000 m3). The methane flow rate peaked at 805,000 ft3/d (22,798 m3/d), then decreased to stabilize at 670,000 ft?/d (18,974 m3/d) after 6 months.

Jan 1, 1989

By C. G. Kirkland

An apparatus for determining trace impurities in Grade-A helium by mass spectrometer methods was designed and built by the Federal Bureau of Mines. Grade-A is the designation for helium commercially produced by the Bureau. Its nominal purity is 99.995 percent. The device, following a suggestion by Deaton, concentrates the impurities in the helium by freezing them out in a coil-and-trap assembly cooled by liquid helium. A known volume of helium is passed through the trap, the concentration ratio determined, and samples of the concentrated impurities are analyzed by mass spectrometer methods. The apparatus has been in service for approximately 20 months and has satisfactorily met all requirements. Over 200 analyses were made of helium contained in conventional cylinders, obtained from the Amarillo, Exell, Otis, and Navajo Helium Plants, during the 6-month period ending March I, 1959. Total impurity concentrations, in parts per million, were as follows: Amarillo, 19.1; Exell, 17.1; Otis, 11.3; and Navajo, 6.6. Neon and nitrogen were the major impurities. Complete data are shown in table 4 in the body of this report.

Jan 1, 1960

By M. L. Skow, Maurice Deul, M. G. Zabetakis

This Bureau of Mines report presents a brief summary of the explosion trends in United States coal mines for the past 160 years. These trends show that in spite of the overall improvements in mine safety, the number of fatalities from ignitions of methane has actually increased in recent years. Suggestions are made of procedures that can be utilized to reverse this trend.

Jan 1, 1972

By Edward D. Thimons

Several types of inflatable stoppings, developed under Bureau of Mines contract for use as mine air barriers during underground production, have been tested by the Bureau. All of the stoppings tested showed significant internal leakage initially but, in all but one stopping, the leaks were sealed with limited effort The stoppings were tested underground in two western noncoal mines under production conditions. The results from the Colorado molybdenum mine showed the stoppings to be generally unsatisfactory for daily mine usage if they are deployed near blasting areas or in locations where near-perfect air seals are required. They were very susceptible to blast damage and seldom were better than 90 percent efficient as air barriers. However, stoppings tested in the New Mexico uranium mine were located substantially distant from any blasting. Because slight leakage past the stoppings was acceptable, they proved very satisfactory in that application.

Jan 1, 1976

"The town of Monson in Piscutaquis County, Maine is the, center of an important site industry. Monson slate has a nation-wide reputation, particularly for electrical switch boards, and the deposits have been worked for the manufacture of such products for many years. Open-pit quarrying is the method most commonly employed in obtaining slate. Underground methods have been used in the Peaon Bottom district near Delta, Pennsylvania, but the quarries that were thus operated are now abandoned. Underground methods have been used more extensively in foreign countries, the most famous example being the slate mines at Angers in France, where an over-head stoping method has been employed successfully for many. It is only under special conditions that underground methods can be successfully used. If the deposit is wide and relatively thin, or if the material is too unsound to constitute a safe roof, open-pit methods must be used, for slate is too low-priced a commodity to justify the heavy expense of any timbering methods. It is only where the deposit is relatively narrow, of great depth, and sufficiently sound to afford a strong roof that ordinary mining may be employed.The best slate beds in two of the three quarries operated at Monson are no worked by underground methods. The chief bed worked by the PortlandMonson Slate Co. is 10 feet thick, stands vertical and strikes N. 63º F. The slaty cleavage is vertical and crosses the strike of the beds at an angle of 5 to 10°. The grain or second direction of splitting is vertical and perpendicular to the cleavage. In addition to the 10-foot bed, to 2-foot beds and one 5-foot bed are available but are not now utilized. In theMonson Maine Slate Co. quarry (the old Pond quarry) a greater number of beds available, but at present quarrying is confined to a single bed about 9 feet thick which dips 30º S.E. and strikes N. 47ºF. The slaty cleavage is vertical and strides N. 45º F., while the grain strikes N. 45-50º W. and is also vertical."

Nov 1, 1920

By Philip W. Holland

The U.S. Bureau of Mines has developed an improved method for determining dissolved helium in water in the concentration range of 4.0 x 10-8 to 270 X 10-8 cm3 He (STP)/cm3 H2O. The method is a modification of a previously reported method that was developed for analrzing surface and subsurface waters in geochemical survey work. Water samples are collected in SOD-cm stainless steel cylinders, and the dissolved gases in a sample are extracted into an evacuated cylinder of equal volume. After addition of 30 psig of nitrogen containing less than 2 ppb helium to the extracted gases, the resulting mixture is analyzed for helium using a helium-tuned mass spectrometer. The helium content of the water sample is determined from an empirical calibration that is established by analyzing standard solutions of helium in water. The accuracy of the method is ±7 pct for helium-in-water concentrations above 10 x 10-8 cm3 He (STP)/cm3 H2O.

Jan 1, 1989

Minimize failures or inefficiency in the operation of in situ mining wells. Approach The proper design, construction and development of wells are important to any in situ leaching operation. To permit cost-effective production from an underground ore body by leaching it in place, many wells are normally installed. Construction and maintenance costs increase with the number of wells, and poor construction and maintenance procedures result in production losses and negative environmental impacts, To minimize these losses and impacts, the Bureau of Mines conducted an investigation to determine the optimum in situ well construction and operating procedures for the minerals industry. Factors considered during the investigation included drilling equipment and procedures; types of well casing and grouting; completion methods, e.g, screening or perforation; and system maintenance. The data collected were used to prepare a manual that offers guidelines

Jan 1, 1984

By Forrest T. Moyer

Injury experience in the mineral mining and processing industries during 1968 was slightly improved in the nonfatal-injury record but worse in the fatality record. The resulting frequency rate of all injuries was slightly better, whereas the injury-severity rate retrogressed appreciably from the figure for 1967. Overall operating activity, as measured by man-hours of worktime, was slightly higher in 1968. However, there were several major segments of the mineral industries in which activity was lower owing to reduced demand for mineral products and to several major work stoppages. These statistics comprise the injury and work experience of all personnel engaged in production, exploration, development, maintenance, repair, and force-account construction work, including supervisory and technical personnel, and working partners and owners at mineral-producing and mineral-processing establishments in the United States. Data concerning officeworkers are excluded except for the oil and gas industry for which such information is not separable. All injury rates and totals are calculated from data before rounding. The data for 1968 are preliminary except for the anthracite, coke, petroleum and natural gas, native asphalt, peat, and slag industries, which are final. The figures represent full coverage for all industries except oil and gas for which coverage is not complete, particularly with respect to small companies.

Jan 1, 1970

By Lisa Steiner, Robin Burgess-Limerick

In 2004, underground coal mines in the United States reported 3,405 injuries to the U.S. Mine Safety and Health Administration (MSHA). Of these, 17 percent were associated with the use of bolting machines, 8 percent with continuous miners, and 4 percent each with scoop/load-haul-dump (LHD), shuttle cars and personnel transport. Analysis of the injury narratives identified five hazards that required attention. They are rock falling from supported roof inadvertent or incorrect operation of bolting machine controls, handling continuous miner cable, collisions while driving underground vehicles and driving or traveling in underground vehicles on rough roadways. The rate of lost-time injuries has steadily decreased during the past 10 years (from more than 10 per 100 FTE in 1995, to six in 2004). However, underground coal mining remains a hazardous industry. One of the contributors to this elevated injury risk is working with or near underground coal mining equipment. Roof bolting machines and continuous miners have been consistently identified as high risk equipment. They account for approximately 24 percent of all injuries to underground coal miners (Sanders and Shaw, 1989). LHD's, shuttle cars and personnel transports are also associated with injuries in underground coal mines (Burgess-Limerick, 2005). Conventional analyses of injury statistics typically provide tables detailing the breakdown of injuries by body part nature of injury or mechanism of injury. Such analyses are worthwhile and may be helpful in tracking broad trends over time. Further information is available in the narrative text field completed for each injury reported. The detail contained in these narratives varies. However, they generally provide some insight into the causes of the injury, such as the activity being performed at the tune of

By B. R. Mohal, F. F. Aplan, S. Chander

"Dust abatement by water sprays involves the subprocesses of 1) collision between dust particles and water droplets, 2) adhesion of particles to droplets, and 3) engulfment of particles by the droplets. A review of the fundamental aspects of these subprocesses shows that collisions between particles and droplets are determined by aerodynamics and the size and surface charge of the particles and of the droplets. However, the adhesion and engulfment subprocesses depend upon the wetting characteristics of the particles. Although wetting agents (also known as surfactants) have been used as dust suppressants in several investigations, conflicting results are available regarding their effectiveness. In this paper, we show that these results can be explained if the effects of coal rank on surfactant adsorption and wetting characteristics are taken into account.The influence of several nonionic surfactants containing polyethoxy adducts on the wetting behavior of coal is presented. The wetting was determined by a modified Walker Test method, and contact angle measurements. The results show that the wettability of coal depends upon coal rank, structure of the hydrocarbon chain of the surfactant, and the number of ethoxy groups in the molecule.IntroductionDue to the inherent nature of the mining process, a large number of particles are generated, a portion of which becomes airborne to create dust. Dust can be aesthetically and environmentally unacceptable and it can also be explosive. Fine particles in the respirable size range ( < 5 urn) are con-sidered to cause lung diseases, namely, silicosis, pneumoconiosis, etc.(1) Several approaches to reduce dust in mine environments are practiced throughout the mining industry. These include decrease in generation of dust through improvements in mine machinery, ventilation (in which lower dust levels are achieved by dilution of contaminated air with clean air), and dust removal methods. Water sprays are most commonly used to remove dust par-ticles. Recently, scrubbers are reported to have been installed on mining machines to remove dust,(2,3) which also make use of water sprays to reduce dust."

Mar 1, 1989

By N. S. Dalal, X. Shi, V. Vallyathan

"INTRODUCTIONThis paper summarizes our recent investigations of the potential role of silicon-oxygen based free radical species in the biochemical mechanism of the lung injury caused by the inhalation of freshly fractured silica. The impetus for this study came from the following observations. Inhalation of crystalline silica is associated with the development of acute and chronic silicosis. Chronic silicosis is characterized by the development of sharply marked concentric fibrotic nodules in the lung. This occurs over a period of several decades with the development of progressive respiratory impairment. In contrast, acute silicosis is manifested by the filling of the alveoli with an amorphous lipoproteinaceous exudate within a short period after exposure, and rapid development of respiratory disability often leading to fatality. Most studies on the pathogenesis of silicosis have focused on the elucidation of cellular mechanisms of cell injury and the development of chronic silicosis. Because pulmonary responses to crystalline silica are distinctly different for · the acute and chronic silicosis, we hypothesized that the acute response is associated with some unique properties of ·freshly formed silica particle surfaces, due to the formation of some reactive chemical species caused by the rupturing or the silicon-oxygen bonds. In occupations involving drilling, tunneling and sandblasting operations acute silicosis can be correlated with this unique surface reactivity of silica. The formation or reactive species was demonstrated, using electron spin resonance (ESR) spectroscopy (Dalal et al., 1986; Fuibini et al., 1987; Hochstrasser and Antononi, 1972). Grinding of quartz crystals under ultra high vacuum (10-10 torr) leads to the formation of Si- and SiO• radicals and these radicals are quenched by exposure to air and other gases (Hochstrasser and Antonini, 1972). ESR signals have also been reported from micronized quartz samples that were evacuated at 413 K (Bolls et al., 1983). In order to find a more direct relationship of such radicals to acute silicosis, we made ESR measurements on quartz dusts freshly ground in ambient air and found- that indeed grinding under ambient environment leads to the formation of the Si• and SiO• type of radicals which decay on storing the dusts in air or in biological buffers (Dalai et al., 1986; Vallyathan et al., 1988). The Si• and SiO radical formation on grinding has also been reported by Fubini et al. (1987). In addition, we recently found that •OH radicals are generated in aqueous suspensions of freshly ground quartz (Dalai et al., 1988; Shi et al., 1988; Vallyathan et al., 1988). We have subsequently carried out detailed cytotoxicity and biological assays on freshly made as well as aged quartz dusts. As summarized below, the results provide new insight into the biochemical mechanism of acute silicosis."

Jan 1, 1988

By C. L. Karr

The U.S. Bureau of Mines is optimizing the design of an air-sparged hydrocyclone. This report summarizes the initial stage of the project-the prediction of collision efficiencies for use in a comprehensive air-sparged hydrocyclone model. The equations of motion are presented in nondimensional form and solved numerically for a small spherical particle passing around a larger bubble in an infinite fluid under the influence of a strong force field. Collision efficiencies are determined from the calculated particle trajectories for values of Stokes&apos; number, K, between 0.01 and 100 and for values of the nondimensional force, W, between 0.0 and 100. These large values of K and Ware needed to model high-performance flotation devices like the air-sparged hydrocyclone; solutions for the required K and W values have not appeared in the literature prior to this study. Effects of changes in particle-to-bubble radius ratio are considered for both viscous and potential flows. The results help predict the improved recovery of fine particles when flotation is performed in a strong force field.

Jan 1, 1990

To reuse chromium, nickel, and molybdenum now lost in stainless and specialty steel-making wastes, and simultaneously to overcome the current environmental problem resulting from landfilling these wastes. Approach A variety of stainless and specialty steelmaking wastes are agglomerated and recharged into the plant&apos;s electric arc furnaces. How It Works Stainless and specialty steel-making wastes such as bag-house dust from the electric arc furnace, dust from the argon-oxygen decarburization unit, grinding swart, and mill scale are blended in proportion to the ratio in which they are generated. Next they are agglomerated on a pelletizer with an addition of a small amount of carbonaceous reducing agent, and air-dried in preparation for being recharged into the furnace. Some mixtures of wastes tested in the laboratory required the addition of binders and/or the use of ovens in lieu of air-drying to produce sufficient pellet strength. Although the optimal maximum particle size of wastes being pelletized is 35 mesh, somewhat larger particle sizes were satisfactorily pelletized during in-plant tests. The photograph shows a typical mixture of wastes and the pellets made from them.

Jan 1, 1981

By Horace M. Lawrence, Edmund S. Leaver

"The sulphidizing filming of minerals in oxide ores as a preliminary treatment to aid their recovery by flotation is known practice. In this work the use of barium polysulphide does not appear to have been considered. A study of the properties of barium lead to the following comparative investigation of the sulphides and polysulphides of the alkaline and alkaline-earth metals. It is thought that barium polysulphide may prove to be a more satisfactory sulphidizing reagent than others now in use under conditions that favor the cheaper barium reagent.For the investigation two fairly typical oxidized ores of copper and lead were selected. The copper ore came from the Big Indian Mine in southeastern Utah, and assayed 3.8% Cu; the copper was present in a sandstone gangue mainly as the carbonates, malachite and azurite, with less than 0.2% as sulphides, or silicate. The lead ore is from the Tintic Standard mine in the Tintic district, Utah. It is typical of the oxidized lead-silver ores of that district; the lead is present in an oxidised form in a siliceous gangue, much: Uncolored by ferric oxide. The sample assayed 5.15% Pb and 11.3 oz. Ag.In addition to the results obtained in this investigation, there are included some results secured by Mr. J. B. Lain, consulting metallurgist of Reno, Nevada, on a sample of ore from the Chino Copper Co. The ore assayed about 1.7% Cu, of which about 0.25% was nonsuiphide."

Aug 1, 1925

By Robert P. Vinson, Fred N. Kissell, Edward D. Thimons

Because of the high number of accidental methane gas ignitions in metal and nonmetal mines, the Bureau of Mines searched for a simple guideline that would allow mine personnel to evaluate the methane hazard in a given mine. Air samples were collected by the Bureau in 53 metal and nonmetal mines and analyzed for trace evidence of methane gas. Samples were collected in the returns and at the working faces. Those mines classified as gassy by the Mine Safety and Health Administration had a significantly higher average methane concentration than those classified as nongassy. Of the 9 gassy mines sampled, 7 had methane concentrations above 100 ppm, whereas only 1 of the 44 nongassy mines had a concentration above 100 ppm. The 100-ppm concentration may be used as a simple and convenient guideline for forecasting the methane hazard in a mine, whether or not the mine is classified as gassy. There was no consistent correlation between commodity mined and methane concentration, nor was there a correlation between mine depth and methane concentration. Neither of these factors can be considered a guideline for predicting methane hazards.

Jan 1, 1979

By Jeffrey Johnson, Thomas Brady, Radford Langston, Mary MacLaughlin, Hendrik Kirsten

The magnitudes and directions of in situ stresses affect the stability of mine openings, as well as the type and amount of ground support needed to maintain a safe working environment for miners. Using hollow inclusion stress cells, researchers from the Spokane Research Laboratory of the National Institute for Occupational Safety and Health obtained two in situ stress measurements from the face of two footwall lateral drifts at the Stillwater Mine near Nye, MT. The first measurement, obtained in 1997, was collected under the valley beneath the Stillwater River. The second measurement was obtained in 2002 under the main frontal massif of the Bear tooth Mountains in the western sector of the mine. Although few data are available, the major principal stress under the valley has been recorded as nearly horizontal in a north-south direction perpendicular to the ore body, while beneath the mountains, stress runs east-west parallel to the ore body. This paper documents the measurements, describes the in situ stress state, and discusses a finite-difference analysis of the biaxial test.

By H. K. Kutter

The pressure pulse generated by an underwater spark \vas investigated in relation to its potential use for rock fragmentation. The study established (1) the relation between the peak discharge current and the peak wave pressure; (2) the relationships among the peak wave pressure, the discharge voltage, and the spark gap width; (3) the type and pulse duration of the generated wave; (4) the percentage of energy transmitted in the spark as a function of spark gap width and discharge voltage; and (5) the percentage of energy converted into the pressure wave as a function of gap width and discharge voltage. Spark-generated fractures were studied in two-and three-dimensional rock and plastic specimens. The laboratory results indicated that the pressure pulse generated by an underwater spark is a potential practical tool for rock fragmentation. The paper contains an appendix describing the capacitive pressure gage specially developed for the laboratory tests.

Jan 1, 1969

By G. R. Hopkins

One of the largest items in the expense of operating a refinery is the cost of the fuel used in distillation and for miscellaneous purposes such as in the heating of buildings and in the generation of electricity, On a B. t. u. basis, the average refinery consumes approximately one-tenth as much fuel as it produces. Theoretically, the fuel consumption at refineries should be much smaller than this, but furnaces can riot be designed to be 100 per cent efficient&apos; and, in addition, a large part of the waste heat is low-temperature heat which would not pay for the expense of recovering it. Annual surveys of fuel consumption at refineries have been made by the United States Bureau of Mines, beginning with 1925. During the 5-year period, 1925-1929, the refineries made steady progress in fuel economy. This is evidenced by the Computed figures of heat requirement Per barrel of crude oil refined, which show a decline from 829,000 B. t. u. in 1925 to 639,000 B. t. u. in 1929 (see fig. 1). In 1930, however, the trend in fuel economy was reversed and the quantity of heat utilized in refining the average barrel of crude oil rose to 672,000 B. t. u. There were undoubtedly a number of reasons for the apparent decrease in fuel economy at refineries in 1930, chief of which were the tendency to carry the distillation farther instead of merely topping the crude and a gain in the consumption of waste oils, such as acid sludge, which in actual practice yield less heat per unit consumed than has been theoretically assigned to oil. The consumption of natural as fuel at refineries has declined since 1927, but this has been more than compensated by a rapid increase in the use of refinery or still gas. The total consumption of oil as refinery fuel in 1930 was not much below the 1925 total, but the consumption of coal has declined rapidly, so that in 1930 liquid and solid fuels contributed only 56 per cent of the total heat units- utilized at refineries as compared with 77 per cent in 1925 (see fig. 2).

Jan 1, 1931