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By Carlton E. Brown

Brown and Yant6/ recently described a microprojection method for determining the particle-size distribution and number concentration of samples of dust collected from the air by such samplers as the Owens jet dust counter7/ and the thermal precipitator8/. This method was developed to obviate or reduce the eyestrain consequent to the regular filar-micrometer method9/ and to save time and work. The article stated that work was in progress on a microprojection method for courting impinger dust samples; this article describes the method developed. ACKNOWLEDGMENTS The assistance of the personnel of the Ventilation Department of the Anaconda Copper Mining Co., Butte, Mont., in developing this method and particularly in suggesting a suitable material to use for the microprojector screen is sincerely appreciated. Much of the work was done in the laboratory of the Anaconda Copper Mining Co. on samples collected in Butte mines during a cooperative study with this Bureau.

Jan 1, 1938

By Robert L. Rough, William E. Eckard

Laboratory data obtained from a Bureau of Mines rotary air core of a well near Sugar Grove , Warren County , Pa . , were instrumental in initiating hydraulic fracturing in the area to stimulate oil recovery from Glade sand oil reservoirs . This report outlines the general geology , lease development , reservoir- rock characteristics , and oil - production history of Glade and Clarendon sand reservoirs in Warren County . The methods of well completion for single- stage and multiple- stage hydraulic fracturing of old and new wells are discussed , and a range of hydraulic fracture treatment data from 29 Glade sand and 10 Clarendon sand wells is presented . A composite decline curve representing oil - production data from six wells shows probable results of hydraulic fracturing . Average cumulative oil production during the first 100 days after hydraulic fracturing with a sand - carrying liquid is compared with production after conventional shooting with liquid nitroglycerin .

Jan 1, 1964

By John G. Kovac

A computer simulation has been developed to estimate the chances of a miner making a successful escape while wearing a SCSR. The model takes into account: (1) training in the use of SCSRs, (2) apparatus integrity, and (3) the oxygen cost of a mine escape. This Bureau of Mines report examines survival odds for a prototypical escape, and illustrates how these odds change when SCSR training is improved.

Jan 1, 2009

By Jack L. Henry

The Bureau of Mines conducted seven pioneering experiments in a 12-inch-diameter Kroll reduction reactor to examine the feasibility of coreducing the chlorides of Ti, AI, and V to produce a homogeneous titanium alloy sponge. The coreduction studies proceeded in a normal manner, and the yields of sponge were comparable with those of pure titanium sponge made in the same reactor. Vanadium concentration was very uniform throughout the sponge cake when VC14 in solution in TiCl4 was fed into the molten magnesium. More difficulty was encountered in feeding solid VCl2 and AIC13. Vanadium and aluminum concentration in the sponge was not uniform, and mechanical difficulties were experienced with the small-scale screw feeder. Although the sponge varied in composition from region to region, the ingots prepared from it were uniform in composition.

Jan 1, 1974

By John B. Gayle

The probable inadequacy of physical tests of coke for the purposes for which they are made has been a subject for discussion for many years. However, little has been published in this connection, even though most workers in the field believe that the physical properties of coke are of major importance in its utilization in the steel and allied industries. In fact, the reproducibility of the recognized tests is largely unknown or can only be approximated. This situation occasions many difficulties when attempts are made to judge the coke-production qualities of various coals or coal blends. During World War II the Coke Production Committee, composed of representatives from industry and the Solid Fuels Administration, concluded that study of existing testing methods and possible improvements would be of material assistance in answering questions relating to coke quality. Since that time the Bureau of Mines has taken samples of coke produced in industrial slot-type coke ovens in connection with studies aimed at extending coking-coal reserves by adding to the list of sources known to be suitable for this purpose. Testing procedures on these cokes were arranged so that the data obtained would yield information on (1) the degree of precision of tests commonly used in the industry, (2) the causes of the known poor reproducibility in several of the physical tests, and (3) possible improvements or modifications of existing physical testing procedures.

Jan 1, 1953

By Joseph A. DeCarlo

According to the annual survey of beehive-coke plants by the Bureau of Mines, United States Department of the Interior, there were 61 plants with 9,549 ovens in the United States on December 31, 1956, This publication in¬cludes only those for which an annual report was filed with the Bureau of Mines. Not all plants listed were active, however, as nearly one-third of those canvassed were idle all year. A compilation of the returns showed that 44 plants with 6,920 ovens were active part or all year and 17 plants with 2,629 ovens were idle throughout the year. The capacity of beehive ovens has fluctuated between 6 and 14 million tons during the past decade. At the end of 1956, the annual coke capacity of beehive ovens on which reports were received amounted to 5.8 million tons. As noted in table 2, however, not all of this capacity was in operating condition, as 2,093 ovens with a capacity of 1.2 million tons were not operable on [ember] 31, 1956.

Jan 1, 1958

By H. P. Hermance

The Ely mine, which at one time was the largest producer of copper in the United States, has been idle for the past 30 years. A remarkably continuous ore shoot probably averaging 100 feet wide and 19 feet thick was mined on about a 25° slope for 3,400 feet on the incline. The ore was massive sulfides containing chalcopyrite, pyrrhotite, pyrite, and sphalerite. The estimated production of the Ely mine is 400,000 tons of ore averaging 3.3 percent copper. Because of the critical position of copper during the recent war, a search for extensions and recurrences of parallel ore shoots at the Ely deposit seemed warranted. The Bureau of Mines surveyed selected areas by geophysical methods, diamond-drilled nine holes, and sampled mine dumps during its investigations, which began in 1942 and terminated in 1946. The diamond drilling totaled 5,229 feet. The logs of the holes include chemical analyses of mineralized sections.

Jan 1, 1949

By Albert E. Long

Preliminary experiments conducted in 1949 with a few diamond bits in which the diamonds in the bit crowns were set in hard-vector directions indicated that a substantial saving could be effected when a high percentage of the diamonds were oriented in this-manner. It was realized, however, that many additional tests would have to be performed before a positive trend could be established and the possibility of coincidence eliminated. Therefore, a long-range series of experiments was planned to investigate various phases of the problems related to the orienting of diamonds in diamond bits. This report (the third in a series) 2/3 presents the information obtained from tests conducted to investigate more fully the effects of orienting high-grade drill bort in diamond bit crowns. In these tests, the drill bort were oriented in both hard-vector and soft-vector directions in the crowns of AX-size bits. Test drilling was done in a dike of saussuritized dacite porphyry similar to a fine-grained granite in hardness e drillability.

Jan 1, 1954

By E. G. King

This report contains experimentally determined heat-content values for cerium dioxide and Columbium (niobium) dioxide in the temperature range from 298° to 1,800° K. There are no previous similar data for Columbium dioxide, and those for cerium dioxide have an upper limit of 373° K. The heat-content and corresponding entropy-increment data are presented in tabular form. Equations were derived to represent the heat contents and heat capacities. The data for cerium dioxide are entirely regular, but those for columbium dioxide show two previously unreported anomalies at 1,090° and 1,200° K.

Jan 1, 1961

By John E. Pahlman

The Bureau of Mines conducted column-leaching tests on 25 domestic Mn ores to determine the feasibility of extracting Mn by in situ or heap leaching with dissolved sulfur dioxide (S02) solutions. The ores tested were obtained from deposits in Arizona, Arkansas, California, Colorado. Maine, Minnesota, Nevada, and South Dakota. Dissolved S02 was found to be effective for leaching Mn; extractions greater than 90 pct were obtained with solution application rates of 1 mL/min from uncalcined, minus 2.5-plus 1.3-cm ore pieces. Leaching these ores with solutions containing only 5-wt-pct S02 and no added H2S04 resulted in Mn being selectively extracted over Fe except when Fe was present as goethite or siderite. Ca solubilization was inhibited by controlling the solution application rate (1 mL/min). The rate of leaching was found to be principally dependent upon the rate at which the leaching solution can penetrate the ore, since the solubilization of Mn upon contact with S02 was observed to be rapid. Despite low water permeabilities of the ores (as low as 10-2 to 10-4 darcy). greater than 90 pct of the Mn was extracted from even the largest ore pieces tested (approximately 10 cm in diameter). It appears, therefore. that leaching Mn opens up the pores, allowing penetration of the leach solution into the ore pieces.

Jan 1, 1988

By V. Vallyathan, Xianglin Shi, N. S. Dalai

While Cr(VI) is a known carcinogen, the underlying biochemical mechanism is still not fully understood (1). In a pioneering study Jennette (2) utilized electron spin resonance (ESR) spectroscopy to demonstrate that a long-lived Cr(V) species is generated during the reduction of Cr(VI) by microsomes in the presence of NADPH. Later Wetterhahn and co-workers (3, 4) showed that incubation of chromate with isolated rat liver mitochondria causes the reduction of Cr(VI), as well as the formation of a Cr(V) species. Analogous Cr(V) species have also been detected in the reduction of Cr(VI) by other cellular systems such as Hanserulla polymorphared (5) and blood cells (6, 7). All these as well as other studies (8-12) have suggested that this Cr(V) species plays a significant role in the mechanism of Cr(VI) toxicity. Thus far, however, the chemical structure of this dominant Cr(V) species formed in cellular systems has not been identified, and this observation provided an impetus for the present investigation. Another reason for undertaking this study was that some recent reports (10-16) suggest that hydroxyl ('OH) radicals may also play an important role in the mechanism of Cr(VI) toxicity. In particular, it has been shown that OH radicals are formed in reactions between Cr(V) species and H2O2 (13-16), and that the radical yield depends on the chemical structure of the Cr(V) species (15). For example, while Cr(V)-diol complexes efficiently generate OH radicals, another Cr(V) species, the tetraperoxochromate (CrO3/8) ion, does not (15). Thus in the present study, we focused our attention on the following: (a) structural identification of the Cr(V) species generated in the reduction of Cr(VI) by subcellular as well as cellular systems, using microsomes, mitochondria, and Escherichia coli; (b) possible detection of OH radical in the same systems since there is no earlier report of chromium-mediated generation of 'OH radicals in a cellular system; (c) possible involvement of molecular oxygen in chromium-related OH radical generation since a recent report (17) indicated that Cr(VI) mutagenesis is strongly oxygen dependent; and (d) elucidation of the mechanism of OH radical formation in these systems.

Mar 1, 1992

By C. M. Frost

The hydrodesulfurization characteristics of a residual fuel prepared from Wilmington, Calif., crude oil were determined at temperatures from 600° to 900° F, pressures of 200 to 800 pSig, and space velocities from 0.2 to 2.0 Vo/Vc/hr, using cobalt molybdate type catalysts. A prediction equation, developed from the experimental data, satisfactorily predicts the fraction of total sulfur that can be removed under any combination of operating conditions within the ranges investigated. Yields and properties of the low sulfur product are correlated with the fraction of total sulfur removed. Kinetic calculations show that the apparent reaction order and activation energy change with space velocity and temperature.

Jan 1, 1970

By H. D. Pallister

A review of? reports and literature on the pyrite deposits at Pyriton, Ala., indicated that a large tonnage of pyrite, some of which contained a small amount of copper, had been mined and shipped to fertilizer plants throughout the South. The information contained in this literature tended to demonstrate that the ore occurred in separate lenses of greater or less extent and of varying thickness and richness in pyrite as well as in copper. The outcrop being parallel with the Atlantic Coastline Railroad and just south of it makes the deposits readily accessible for shipment. Slopes could be sunk as they were in the past in the ore body if it were of sufficient grade and thickness, and the ore could be hoisted up the slope and milled close to the slope mouth with an ample supply of water from Talladega Creek, which follows the outcrop closely.

Jan 1, 1949

By C. H. Elder

A 5-hole pattern was drilled from the surface at a site near Oak Grove, Jefferson County, Ala., to degasify the gassy Mary Lee coal bed in advance of mining. Gas and water production was monitored for 1 year, 4 months to allow gas flow to stabilize fully. A thickened water stimulation treatment was designed and applied in one hole of the pattern to evaluate this degasification technique for the Mary Lee coalbed. A gas production rate of 70,000 fts/day after stimulation treatment indicates that the use of vertical boreholes coupled with hydraulic fracturing in advance of mining the Mary Lee coalbed would provide for more rapid degasification and could provide a possible source of natural gas.

Jan 1, 1974

By D. W. Butner

As a part of the Bureau of Mines program for the discovery and development of critical and essential mineral deposits, the Darwin district, Inyo County, Calif., was chosen for investigation as a possible source of, tungsten ore. Two properties were active in the district at the time. One was producing tungsten concentrate and the other was preparing to produce tungsten concentrate as a byproduct in the milling of lead-zinc ore. The objective of the project set up by the Bureau was to investigate promising areas and to sample, thoroughly those which preliminary inspection indicated contained tungsten ore. Work was begun November 17) 1941, and completed January 19, 1942. In the course of the project, 18 localities were inspected and 9 were sampled. The following pages brief the history, note the location, and outline the physical features and geology of the district. The work performed by the Bureau of Mines is described and supplemented with assay maps.

Jan 1, 1949

By Virgil A. Marple, Susanne V. Hering

"5.1 IntroductionTraditional impactors do not offer much size resolution for submicrometer particles; typically their finest size cut is around 0.4 µ.m. Yet for many aerosol applications it is useful to be able to size segregate aerosols in the size range below 0.4 µ.m. Diesel emissions, welding fumes, cigarette smokes and photochemically generated smog aerosols typically exhibit mass median diameters between 0.1 and 0.6 µ.m. When sampling these aerosols with a traditional impactor, fifty percent or more of the aerosol mass can penetrate the final impactor stage. Allhough the material can still be collected on a backup filter, the filter gives no size resolution. As a result, the investigator has no size information on a substantial portion of the sample. One needs a sampler that size-segregates the majority of the aerosol mass. A lower size cut of 0.1 µ.m or less is required for most combustion smokes and smog aerosol s.To obtain smaller cutpoints two types of impactors have been developed, namely low-pressure impactors and micro-orifice impactors. Both instruments can provide cutpoints as small as 0.05 µ.m. Low-pressure impactors were introduced more than twenty years ago (Stem et al., 1962), and a variety of these samplers are in use today. Micro-orifice impactors have been developed at the University of Minnesota within the last five years (Marple et al., 1981 ). To date theirs are the only examples of these instruments in use.5.2 Operating PrinciplesThe low-pressure and micro-orifice impactors use two different approaches to achieve their very small particle-size cuts. Low pressure impactors resemble ordinary impactors, but are operated at reduced pressures of 5-40 kPa (0.05 - 0.4 atm). They take advantage of the decreased aerodynamic drag on particles that occurs when the mean free path in the air is as large or larger than the particle diameter. Micro-orifice impactors operate at near atmospheric pressure, but employ very small orifices, 40 µ.m to 200 µ.m in diameter. The streamlines of the air impinging upon the impaction plate have correspondingly smaller radii of curvature; the air is accelerated more quickly, making it more difficult for the particles to follow. The basic operating principles for both types of impactors are evident from the particle Stokes number, defined as:"

Mar 1, 1989

By Ronald A. Munson

Samples of the naturally occurring zeolites phillipsite, clinoptilolite, erionite, and chabazite have been surveyed for their gas adsorption, ion exchange, and other characteristics. Chabazite and erionite, which are generally more stable, also have higher methane adsorption capacities than do the other natural zeolites. Both natural erionite and natural chabazite are classified as small-port zeolites on the basis of their inability to adsorb chlorotrifluoromethane. In the range of 8 to 100 mesh, the adsorptive capac-ity of natural zeolites is improved only slightly by a decrease in particle size. The capacity of natural clinoptilolite to adsorb methane is increased by cation replacement by the hydrogen ion and decreased by exchange with calcium ion. Natural phillipsite, which is easily decomposed by heat, adsorbed methane to a limited extent.

Jan 1, 1973

By W. R. Crane

Subsidence and ground movement are phenomena common to and attendant upon practically all large-scale mining operations, and under certain conditions may occur in all workings, large and small. The interpretation of the cause of failure in rock masses involves a study of the nature of plants of weakness common to all rocks. The dominating planes of weakness can readily be determined by observation in any given locality, and in order of importance in the study of subsidence are (1) faulting planes, (2) bedding planes, (3) joint planes, and (4) other prominent planes of weakness such as thrust and shear planes and contacts. This report has mainly to do with the third item, joint planes, and is a preliminary statement which t to be followed by a more complete report in bulletin form.

Jan 1, 1931

By J. Baicker

A two-inch diameter probe containing an intrinsic germanium detector, a canister-type solid cryogen cooling system, cooled FET preamplifier, linear amplifier, high voltage supply, analog-digital converter, microprocessor, buffer memory, bidirectional cable link, and all power supplies has been designed, assembled and tested. A surface support vehicle was designed, built and outfitted. A mini-computer system was constructed and preliminary software developed and tested. A special handling system for a Cf-252 neutron source was designed and has been ordered. The entire system (less the neutron source) is ready for its first field tests. Lab description of the system is presented.

Jan 1, 1978

By Rolf S. Paine

The Bureau of Mines studied the presplitting technique used for control-ling overbreakage in the walls of a vertical shaft at the U.S. Army Corps of Engineers Littleville Dam project near Huntington, Mass. The periphery of the shaft, the dimensions of which were 16-1/2 feet wide by 21 feet long and 52 feet deep, was presplit (cracked) in the solid to a depth of 48 feet prior to full-depth sinking. Presplitting prevented overbreak in a fairly soft schist and provided sound self-supporting walls which required very little scaling.

Jan 1, 1965