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By D. J. Stoops

The object of the research described in this paper was to investigate the effect of metallurgical and surface treatments on the corrosion behavior of arc-melted reactor-grade zirconium in cupric or ferric chloride solutions. An apparatus was constructed and specimens of various metallurgical conditions and surface treatments were tested for 6 days at 35° C., with aeration. Some correlations were observed between corrosion rate and the metal's condition and treatment, Specifically, the unattacked or least attacked specimens were those that had been etched as a final treatment before testing. The most severely attacked specimens were those that had been vacuum-annealed as a final treatment before testing. The moderately attacked specimens were those neither vacuum-annealed nor etched, but having a final surface treatment which left a cold-worked surface. Attack by cupric and ferric chloride was by pit- ting with no preference for grain boundaries, The corrosion scale was cow posed predominately of very fine zirconim particles, Particles from the FeC1,-corroded specimens were more pyrophoric than those from CuCl2-corroded specimens, and appeared to have a higher surface area to volume ratio. Comparison of results to those of previous investigators showed that at certain salt concentrations the more pure, reactor-grade zirconium was quite resistant to attack while the less pure, graphite-melted zirconium was severely attacked.

Jan 1, 1962

By Daniel R. Babich, Jeffrey R. Vipperman, Eric R. Bauer

Prolonged exposure to loud noise can cause permanent damage to the auditory nerve and/or its sensory components. Despite regulations and efforts by government and industry to reduce noise-induced hearing loss (NIHL), it is still a problem in the U.S. coal mining industry. The Mine Safety and Health Administration noise standard (30 CFR3 62), which was enacted in September 2000, is aimed at reducing NIHL in the mining industry. To address NIHL in various aspects of coal mining and provide the necessary information to effectively implement control technologies, the National Institute for Occupational Safety and Health conducted a cross-sectional survey of noise sources and worker noise exposures. Noise surveys consisting of full-shift worker noise exposure (dose) determination, time-motion studies (task observations), and equipment and/or area noise profiling were completed in 8 underground coal mines, 10 surface coal mines, and 8 coal preparation plants. The studies revealed that more than 40% of all workers monitored were subject to noise exposures above 90 dBA TWA8. A summary of these studies is presented, their application to administrative and engineering controls is discussed, and exposure reduction methods are reviewed.

Jan 12, 2006

By C. J. Walker

The Bureau of Mines undertook a theoretical and laboratory study to determine the feasibility of using ethylene as a tracer for natural gas in underground gas-storage reservoirs. The study indicated that ethylene was a useful gas tracer in underground gas storages. Tracer losses were not excessive. Laboratory tests were conducted at pressures as high as 500 psia in both wet and dry consolidated-sandstone cores, evaluating tracer loss with gas blends containing natural gas with different concentrations of ethylene tracer. Under certain conditions losses were less than 17 percent.

Jan 1, 1966

Vanadium, molybdenum, and a titanium-10 percent vanadium alloy were evaluated for their susceptibility to stress corrosion cracking in a number of corrodents. Tests were conducted utilizing conventional U-bend techniques with subsequent evaluation in a pneumatic constant-load apparatus. Vanadium and molybdenum were generally resistant to stress corrosion cracking in the media studied. U-bend specimens of vanadium showed evidence of stress corrosion cracking in 6 li hydrochloric and 18 li sulfuric acids; however, tensile stress specimens exposed to these solutions did not exhibit stress cracking. Similar results were obtained when U-bend specimens of molybdenum were immersed in 10 percent formic acid. Titanium-10 percent vanadium alloy was susceptible to stress corrosion cracking in 10-percent (2.85 li) hydrochloric acid solution. Heat treating the alloy greatly reduced its corrosion rate and its susceptibility to stress cor-rosion cracking in this medium.

Jan 1, 1965

By Sidney Katell

The reaction of coal, oil, or natural gas with air and oxygen and/or steam yields a gas containing varying amounts of impurities. Depending on the raw material and the end use of the product, these impurities include solids, such as dust or slag, and gases, such as hydrogen sulfide, carbon dioxide, and nitrogen. Considerable effort has been expended in developing and operating purification systems, and the literature is replete with equipment data and operating results. The research problems, the design, and the operation of the various systems have been the subjects of patent applications, journal articles, and textbooks.

Jan 1, 1959

By Russell E. Griffin

Dielectric constants and dissipation factors were measured for six rocks over the 20-to 100-megahertz frequency range by means of the susceptance-variation method. Results for both dry and moist specimens are presented and compared with data reported by others. Loss factors calculated from the data presented are important to the Bureau's study of rock fragmentation by means of dielectric heating.

Jan 1, 1967

By Frank C. Andreuzzi

The Federal Bureau of Mines conducted a demonstration project to reclaim 125 acres of abandoned strip-mined land in Lackawanna County, Pa., for public recreational, historical, and educational use as a park. The Bureau was involved in the development of the general site plan, and engineered and supervised the basic land rehabilitation. The park's Facilities include outdoor recreational activities, picnic grounds, children's play areas, primitive overnight camping, and winter sports. A major attraction is the Anthracite Museum constructed by the Pennsylvania Historical and Museum Commission The project may serve as a prototype for reclaiming existing and future surface-mined lands.

Jan 1, 1976

By R. P. Vinson

The Bureau of Mines examined the effects of high humidity and water droplets on the GCA Corp. real-time aerosol monitor (RAM--l). which uses a lO4mm cyclone preseparator. Tests were conducted both in a laboratory and in a full-scale model mine entry. The laboratory tests were conducted in a test chamber saturated with moisture and water droplets. Under these extreme conditions. the RAM-I responded by indicating dust concentrations of 1-1/2 to 2 mg/m3? although the air was dust free. Within the first 2 h of each test. water accumulated in the cyclone and affected the cyclone particle separation characteristics. resulting in readings of 3 to 4 mg/m3. In addition. condensation formed inside the RAM-I case and affected the liquid crystal display (LCD). However. the full-scale mine entry tests revealed that the RAM-I can function ac-ceptably in an atmosphere of water vapor and water droplets similar to the most severe conditions found in an underground mine.

Jan 1, 1984

By Gary W. Krantz

Fibered, portland-cement-based gunite products were applied in the Bureau of Mines Lake Lynn Laboratory Experimental Mine using a variety of pneumatic guns and gunning crews, The demonstrated wet-mix (with silica fume), dry-mix, and surface bonding products were sampled by the Bureau and subjected to a suite of engineering analyses. Gunite flexural and compressive strength, rebound, permeability, porosity, dust loading, shooting rate, crew requirements, and cost factors were evaluated. Steel, fiberglass, or polypropylene fibers were contained in all but two of the gunires tested. Both Bureau and private testing laboratory analyses are provided for some products. Electron probe micro-analysis and X-ray diffraction analysis were performed on the silica fume fraction of the wet-mix gunite to characterize the dust. Aggregate size fraction distribution analyses were performed to provide strength relationships. Results indicate that all of the commercially available fibered-gunite materials tested can provide beneficial sealant, spall prevention, or roof stability control attributes for underground mining environments when applied by an experienced crew using a well-maintained gun, in accordance with product manufacturers' recommendations and when used for the designated purpose.

Jan 1, 1984

Coaxial cable structures form the subject of substantial theoretical and experimental investigations either directly related, or which can be extrapolated, to the communications needs and environments of U.S. coal mines. Communication systems based on "guided" waves, of which "leaky" coaxial cables are one implementation, are attractive candidates for providing a range of communication functions primarily along haulage ways, and possible also within sections up to the working face. (However, there are still strong reservations as to whether a practical coaxial cable sys tem could provide sufficient communications coverage within a section. ) In this Part, we present the results of some theoretical calculations of the performance of leaky coaxial cable communication systems. We also analyze the applicability of the theoretical and experimental results obtained by other researchers to the needs of U.S. coal mines. In particular, this investigation has been focused on the utility of relatively low cost, conventional, flexible, coaxial cable at frequencies covering the LF through HF bands and extending into the lower part of the VHF band, as opposed to relatively high cost, special semi-rigid, coaxial cable* at frequencies in the VHF and UHF bands. There are three major design alternatives for coaxial cable communication systems considered in this chapter: • Base station feeding a coaxial cable with high surface transfer impedance (holes in outer conductor, e.g., braid construction). • Base station feeding a coaxial cable with repeaters (U.K. experiments). • No base station, direct communication via a coaxial cable with periodic radiative structures.

Jan 1, 1974

By L. B. Pankratz

Low-temperature heat capacities, high-temperature enthalpy increments, and the enthalpy of formation at 298° K were determined calorimetrically for vanadium subnitride (VN0.465). The low-temperature investigation gave S°298.15 = 6.379 ±0.005 cal/deg mole, and a combustion calorimeter investiga¬tion provided ?Hf°298.15 = -31.80 ±0.60 kcal/mole. The two quantities were combined with the high-temperature data to give standard values of enthalpies of formation and free energies of formation above 298° K. These and related thermodynamic functions were tabulated to 1,800° K. Similar data are included in the range of 298° to 1,600° K for the mononitride, VN.

Jan 1, 1971

By T. J. Ballard

The Ore Knob mine, in Ashe County, N.C., was one of the largest producers of copper in the eastern states during the 1870's. The ore occurs in a fissure vein, which strikes N. 64° E. and dips nearly vertical. The country rock is granite gneiss. Drilling indicated that the vein structure is approximately 200 feet wide and 1,500 feet long. The vein material shows evidence of replacement of the original gneiss by sulfides. Solution cavities in the vein were noted in some places. The ore minerals and pyrrhotite, chalcopyrite, pyrite, and minor quantities of sphalerite. The gangue contains biotite, magnetite, albite, calcite, and many silicate minerals.

Jan 1, 1948

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 J. D. Davis

"Introduction.Sixty years ago, M. Berthelot found that ethylene could be selectively absorbed from gaseous mixtures by concentrated sulphuric acid, and that the compound formed by the chemical union of the gas and acid was readily decomposed by heating with water, yielding ethyl alcohol. Only within the last few years has there been any attempt to make use of this discovery technically.Bury*, working in England at the Skinningrove Iron Works and on a commercial scale, developed a technical method for converting, the ethylene of coke-oven as into alcohol. With a gas containing less than 3 per cent of ethylene, he obtained a yield of 1.6 gallons of alcohol per ton of coal carbonized.De Loisy** perfected a technical method for treatment of coke-oven as for alcohol. Evidently this work was carried out on a semi-commercial scale. His method is based on the use of catalytic agents for hastening the absorption of ethylene by sulphuric acid. He uses part of the spent acid for drying the gases and pact for the manufacture of ammonium sulphate. Excess acid is reconcentrated by waste heat. Others have worked on the problem, but so far there has been no large recovery of ethylene from coke-oven gases. The chief difficulty seems to lie in the low efficiency (about 50% of methods and tae relatively low concentrations of ethylene in the gases treated. Gas from Trent amalgam*** contains much larger percantages of ethylene than does coke-oven gas, as Will presently be shown, and if it should ever prove practIcal to treat industrial ;as for alcohol, this gas would offer attractive possibilities,* Bury, Ernest, Ethylene as Alcohol from Coke-Oven Gas: Gas Journal' Vol. 148, D. 30, 1919, pp. 718.** DC Loisy, M.E., Sur un procede' industrial de fabrication syntlotique de l'alcool et de l'ether a partir des gaz de distillation de la houil Comp Rend, vol. 170, Jan. 1920, p. 50-3.*** A paste consisting of approximately part oil such as that obtained as for cleaning coal. See Perrott. in cleaning coal, Chem 3 parts finely pulvarized coal and 1 final product in the Trent, process StJ, and Kinney, S.P. The use of oil Vol. 35 August 3, 1921, p, 183.. & Met."

Nov 1, 1922

By D. R. Corson

The Bureau of Mines instrumented two similarly backfilled stopes--one filled in the normal manner and the other with the fill densified using vibratory compactors--to evaluate the effect of fill compaction on subsequent vein-wall closure proposed as a adjunct process for strengthening cemented fill. Hydraulic pressure cells to monitor pressures within the fill and mechanical closure devices to measure vein-wall movement and the procedure for their installation are described. The field compaction work was generally performed manually by utilizing small commercial concrete vibrators. A prototype immersible vibrator using slusher cables to propel the vibrator in the stope was used on several lifts of fill. Although compaction efforts were less effective than anticipated in increasing the final density of fill, analysis of the field data does indicate somewhat improved strain characteristics and an increased pressure buildup for the densified fill. The effects of a prolonged period of inactivity and of rock burst occurrences in the immediate area are also reflected in plots of strain and pressure within the two instrumented stopes.

Jan 1, 1971

By Wilbert J. Huff

The Explosives Division of the United States Bureau of Mines makes certain laboratory and field investigations that deal with explosions, explosives, ignition, and combustion, together with many related problems, such as the cause and prevention of fires, and certain fundamental scientific questions bearing upon the determination of the chemical and physical mechanisms underlying some of the important phenomena encountered. Its work on explosives has been particularly directed toward determination of the chemical and physical characteristics of explosives designed for use in coal mines and in a more limited way to those used in metal mines, tunnels, quarries, and other engineering operations. This testing is handled by two units of the Explosives Division, as follows:

Jan 1, 1937

By John E. Pahlman

The Bureau of Mines has conducted research on a dual leaching method that offers the potential for the economic recovery of the silver, as well as of the manganese, contained in some domestic manganiferous silver deposits. The method consists of an initial leach of manganese with aqueous sulfur dioxide (S02) followed first by a neutralization rinse, and then by a second leach with cyanide solution for the extraction of silver. Refractory silver in these ores was either (1) intimately associated with the manganese, (2) chemically resistant to cyanide leaching, or (3) rendered inaccessible to cyanide leach solution by the surrounding manganese mineralization. Less than 10 pct of the silver was extracted when minus 2.5-plus 1.3-cm ore pieces were leached directly with cyanide. However, extractions of 25 to 82 pct of the silver and 65 to 96 pet of the manganese were attained in laboratory column-leach tests using the dual leaching method on equivalent-sized ore pieces from seven domestic deposits.

Jan 1, 1987

By K. C. Dean

Time and motion studies were made by the Federal Bureau of Mines on the hand and machine dismantling of scrapped auto starter motors, generators, and alternators for recovery of copper, aluminum, and iron. The studies showed that an individual with power handtools and convenient access to a hydraulic press, power bandsaw, acetylene torch, and power lathe could, in an 8-hour day, disassemble about 100 starters, or 150 generators, or 30 alternators. The scrap copper yield would be 280, 390, and 45 pounds, respectively, and the iron yield would be about seven times the copper weight. About 100 pounds of aluminum would be obtained from the alternators.

Jan 1, 1976

By Albert E. Long

This paper presents a description of the operational mechanics involved in block-caving a granodiorite-capped, limestone deposit. This method was used for 24 years at the Crestmore mine, near Riverside, Calif., which was operated by the Riverside Cement Co. as a source of raw material used to manufacture a portland cement. The Crestmore mine is the only place where a block-cave method has been used to mine a limestone deposit. Structurally, limestone is relatively strong, and it is not usually considered to be a substance amenable to mining by block caving. It is therefore a credit to the engineering department of the Crestmore mine that it developed a satisfactory, relatively efficient method of block-caving a structurally stable rock. In the discussion, covering the methods applied to produce about 7.9 million tons of limestone and granitic rock materials by block caving, particular emphasis has been placed on an assessment of (1) physical properties of the deposit, (2) ground pressure and support, (3) methods used to induce fragmentation and maintain cave action, (4) surface and subsurface subsidence, (5) secondary blasting of oversize, (6) production rate, (7) safety, and (8) the advantages and disadvantages of the cave method as applied to this specific limestone deposit.

Jan 1, 1958

By Charles L. Kimbell

World political events that occurred subsequent to yearend 1989 but that bear heavily on the global mineral industry have been of such significance that they cannot be disregarded, 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. The section also includes an element with some broad statistical information, but this is included last rather than first for two reasons: the information is subject to considerable re- vision as additional data become available and as preliminary returns are corrected; and the authors view it as less important than the events that govern the statistics. The Near East and the Crisis There.- Of all 1990 political events influencing the world's mineral industry, the Iraqi invasion of Kuwait and the remarkable events that followed this aggression must head the list. The almost immediate imposition of economic sanctions, involving embargoes on shipment of virtually all goods into and out of Iraq, caused severe dislocations in the production and trade of mineral commodities, not only within the region itself, but with a ripple effect, into other world areas as well.

Jan 1, 1992