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By N. S. Dalal, V. Castranova, X. Shi, W. Wrr, V. Vallyathan

"SUMMARY Data presented here indicate that freshly fractured silica exhibits surface characteristics and biologic reactivity distinct from aged silica, and on this basis we propose that these surface features may lead to enhanced manifestations of lung Injury. Grinding of silica produces ~10"" Si and SI-O (silicon-based) radicals per gram of dust on the particulate surface which are characterized by an electron spin resonance (ESR) spectrum centered around g = 2.0015. These silicon-based radicals react with aqueous media to produce OH radicals, which are demonstrable using a DMPO spin trap. The concentration of silicon-based radicals in silica decreases with aging in air and exhibits a half-life of ~30 h, whereas its ability to generate OH radicals in aqueous solution decreases with a half-life of ~20 h. However, on storage in aqueous media, the concentration of silicon-based radicals end the dust's ability to generate OH radicals decrease significantly within a few minutes. Freshly ground silica is also more biologically reactive than aged silica, because freshly crushed silica activates a greater respiratory burst In alveolar macrophages than aged silica, i.e., storage of ground dust in air decreases silica-Induced superoxide anion secretion, hydrogen peroxide release, and NBT reduction by 25%, 68%, and 43%, respectively. Furthermore, compared to aged silica, freshly ground silica exhibits a greater cytotoxic effect on cellular membrane Integrity, i.e., a 1.5-fold increase in LDH release from macrophages, a 36-fold increase in hemolytic activity, and a three-fold increase in the ability to induce lipid peroxidation. Because acute silicosis is frequently associated with occupations in which freshly fractured crystalline silica of respirable size is generated, the present study suggests that fracture-generated silicon-based radicals may play a significant role in the pathogenesis of this disease. AM REV RESPIR DIS 1955; 133:1213-1218IntroductionOccupational exposure to crystalline silica can be associated with either chronic or acute pulmonary disease. Chronic silicosis becomes manifest 20 to 40 years after first exposure and is characterized by development of concentric hyalinized nodular lesions in the lung with the de-velopment of dyspnea over a period of several decades. Acute silicosis, on the other hand, is manifested by a rapid on-set after exposure and is characterized by the accumulation of an amorphous granular lipoprotein exudate in the airspaces and rapid development of respiratory disability within a few years (1-3).Information is growing concerning the etiology of chronic silicosis. Studies sug-gest that several mechanisms may be in-volved in the development of fibrosis. Lung injury may result from silica-induced release of lysosomal enzymes from alveolar macrophages (4, 5). In ad-dition, silica-induced activation of su-peroxide anion and hydrogen peroxide release from alveolar macrophages may result in oxidant-induced damage to lung parenchyma (6). Silica exposure can also result in the release of mediators from alveolar macrophages which enhance the proliferation of fibroblasts and the syn-thesis of collagen by these pneumocytes (7, 8)."

Jan 1, 1988

By W. H. Rinkenbach, C. A. Taylor

"Among the recently patented detonating compounds that have been suggested as substitutes for the commonly used fulminate of mercury is the normal lead salt of trinitroresorcin, or styphnic acid. As no data concerning its use or practi¬cability were available, a study of its properties was made in the explosives laboratory at the Bureau of Mines experiment station at Pittsburgh, Pa. This paper embodies the results obtained.Normal lead trinitroresorcinate was first prepared and patented*** by Herz; it probably found some use during the World War, but no record of its performance is available,Preparation of Lead Trinitrpresorcinate.In his patent specifications, Herz states that the normal salt may be obtained in a quantitative way by precipitating a multiple of the equivalent weight of the lead salt of a strong inorganic acid - such as lead nitrate - in the presence of a weak organic acid - such as acetic acid - by heating with a Teak solution of the alkali-metal salts or alkaline-earth salts of trinitroresorcin. Herz gives the following example: 245 grams of dry trinitroresorcinand 290 grams of crystalline sodium carbonate are dissolved in in 18.8 liters of boiling water, to which 77 c.c. of glacial acetic acid is added. The toiling solution is mixed with a boiling solution of 650 grams of lead nitrate in 1.4 liters of water, stirring rapidly; and the mixture is boiled for two minutes, after which it is cooled quickly with constant stirring. The precipitated crystals are then filtered off, washed several times with cold water, and dried."

Oct 1, 1923

Provide a means to (1) rapidly disconnect a multifunctioning signal channel from a multichannel data collection system, (2) protect electronic devices from damage while causing the minimum amount of data collection disruption, and (3) operate electronic devices under gassy mine conditions. Background Data collection system instrumentation and cables are often located in hazardous areas of underground coal mines. As a result, frequent damage to the instrumentation cables occurs from roof falls, heavy equipment, and the relocation of air, water, and power lines. A similar problem exists in surface areas where cables and instrumentation can be damaged by animals and by vehicle traffic. Without a circuit-breaking feature, the damaged cables could cause instrumentation to be ruined, cause power supply failure, and otherwise disrupt data collection in some situations the lack of a circuit-breaking feature might cause an ignition in a methane atmosphere.

Jan 1, 1990

The principal activities of the Bureau of Mines Explosives Research Center from July 1, 1963 to June 30, 1964 are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1964; in general, the research reported in these publications antedates the report period. Part 3 describes a short-term investigation into safety problems associated with shipping of molten sulfur; this investigation is not at present destined for publication elsewhere.

Jan 1, 1965

By G. St. J. Perrott, N. A. Tolch

"The testing of explosives for permissibility for use in coal mines was begun by the technologic branch of the United States Geologic Survey in February, 1909, and continued by the United States Bureau of Mines from July, 1910; this testing has been carried on from year to year as the explosives were submitted by manufacturers. As a result of these many years of testing for permissibility a large amount of data has accumulated regarding the characteristics of permissible explosives. The manufacturer expects a sample of explosive submitted for test to meet the requirements for permissibility, otherwise the sample would not be submitted. However, in spite of the careful regulation and preparation of the formulas a certain percentage of explosives fails to pass the gallery tests. It is therefore interesting to note the proportion of failures at the gallery for a given composition of explosive. The fact should be emphasized that this discussion deals with all explosives submitted for test, both those which passed the tests and those which failed to pass. Explosives that failed to pass the tests were never designated as permissible explosives and have never appeared on any list of explosives permissible for use in coal mines.The Bureau of Mines classifies permissible explosives in two ways, according to the quantity of poisonous gases produced and according to the characteristic ingredient of the explosive.4 In this paper only two types of the latter classification are considered, as follows:"

Dec 1, 1929

By G. A. Crowder

Far infrared spectra, most of them in the region 15-200 microns and for both the liquid or solution state and for the vapor state, were obtained for twenty-seven compounds.

Jan 1, 1965

By Frank G. Horino

This report describes an instrument designed by the Bureau of Mines for quantitatively identifying texture of rock surfaces produced by grinding or extremely rough surfaces beyond the range of commercial surface measuring instruments. The transducer for the instrument is a linear variable differential transformer that converts mechanical motion caused by surface roughness, waviness, and lay to an electrical output. The electrical output is recorded graphically as an X-Y plot of the line traversed on the rock surface. Details of the synthesized device and its calibration are given. The sensitivity of the unit is 2 percent of the scale setting of the amplifier. The horizontal scale is adaptable from ¼ inch to 15 inches of specimen length with a sensitivity of 0.01 inch if a 10 to 1 magnification is used and 0.1 inch if a 1 to 1 magnification is used.

Jan 1, 1968

By Jack A. Touseull

The Bureau of Mines has developed a simple stereographic method of analyzing the orientation of single and intersecting planes of weakness in vertical pillars of parallel symmetry. From this method, it can be determined if planes of weakness transect the full horizontal cross section of a pillar. A major finding resulting from this method was that intersecting planes of weakness can transect the full horizontal cross section of a pillar even though the individual planes do not. This paper provides step-by-step instructions for using this method.

Jan 1, 1977

By G. L. Oldright

The past reputation of zinc as an ingredient in lead blast furnace slags has been bad. Zinc is thought of as a cause of accretions in the shaft of the blast furnace, of hot tops, of the formation of "zinc mush" in the crucible and forehearth, of leach rich slags, of viscous slags, and of low capacity in smelting.

Jan 1, 1934

Graduate education is an integral part of the Center's research program. The scope of. work and the duration of each research project is calculated, in part, by taking into consideration the needs of the graduate research program and graduate training. Full development of student involvement, as demonstrated by the research practicum which is offered to qualified senior undergraduates at Penn State University and is designed to acquaint them with research methods and techniques and inform them of the opportunities available in this field. and the fulfillment of graduate program requirements are of the utmost concern. The Pennsylvania State University and West Virginia University have accredited mining engineering curricula and rank among the schools with the largest enrollment in this area in the nation. The number of undergraduate students enrolled in mining engineering at Penn State and West Virginia University account for nearly 20%, of the total undergraduate enrollment in this discipline in schools across the United States. The Pennsylvania State University. West Virginia University, Massachusetts Institute of Technology, University of Minnesota, and Michigan Technological University, have granted a total of thirty-five (35) doctorate and masters degrees which can be directly attributed to research conducted in the Center.' Of these graduates, fifteen(15) have found employment in the mineral sector of the economy, i.e., in private industry, with government agencies, and at various universities, worldwide. In addition, a number of those graduating with masters degrees are currently pursuing a doctorate degree.

Aug 31, 1989

By W. L. Crentz

The Black Mesa coal field is part of the Hopi and Navajo Indian Reservation in Apache, Navajo, and Coconino Counties, Ariz. The field is in an isolated area with the nearest railroad 70 to 90 miles to the south. Travel is restricted by roads that become impassable during inclement weather. The area is a mesa and rises from 500 to 2,000 feet above the surrounding territory. Water is very scarce, and the nearest stream of any consequence is the Colorado River about 90 miles northwest from the center of the field. Coal beds are found in the Mesaverde formation of the Cretaceous age, but they are uncorrelated and range from subbituminous to bituminous in rank. Huddle2/ estimates the reserves of subbituminous coal in Arizona at about 15 billion tons, most of which is in the Black Mesa field. The geology of the field has been reported by Campbell and Gregory.3/ Coal production is small, and the output is used almost exclusively for domestic fuel in the Indian schools, missions, and trading posts.

Jan 1, 1955

By R. V. Ramani, B. K. Belle

The increased effectiveness of a two-phase spray system (TPSS) over a single-phase spray system (SPSS) for dust suppression is reported in several laboratory studies. The dust collection efficiencies of SPSS and TPSS were studied in a model experimental longwall gallery facility at Pittsburgh Research Laboratory at NIOSH (USA). The experimental design consisted of two factors: pressure, and airflow. Each factor had three levels. SPSS experiments were conducted at only one pressure (1035 kPa) which is nearly 1.5 times higher than the highest air and water pressure for TPSS experiments. The results of the study are presented in this paper. While it appears that TPSS performed better than SPSS, the data is not sufficiently conclusive on this aspect. The differing spray characteristics of the chosen TPSS and SPSS nozzles did not allow a direct comparison of the two systems. In the TPSS arrangement, considerably greater turbulence in airflow is created around the shearer; it is likely that at least in the immediate vicinity of the tailgate drum, there is a roll back of the dust/mist cloud into the walkway. Therefore, positioning of the personnel upwind of the tailgate drum is necessary to avoid high dust exposures. The rate of decrease in concentration with TPSS is higher than that with SPSS. This may be due to the greater atomization of the water. The test set-up did not allow the study of conditions when coal is cut from tail to head where the potential for personal exposure is high. Changes in the experimental design are necessary to overcome some of the reasons expected for the inconclusive results.

By C. M. McCulloch

The methane content of virgin bituminous coalbed can now be measured accurately in the field with exploration core samples from vertical boreholes. The gas content of the coal per unit weight can be used either to design a mine ventilation system or to determine if degasification of the coalbed will be necessary before mining, and to determine the gas resources in the coalbed. The equipment necessary to conduct the test costs less than $50. The gas con-tent of the coal in place in the ground is determined by summing the gas lost from coring, gas measured during desorption, and the residual gas in the coal. Upon removal from the borehole, the core sample is placed in an airtight container and des orbed for several weeks until the desorption rate is below 0.05 cm3/g for 5 consecutive days. The gas lost from the core while it was being cored and the residual gas are estimated by a new graphical method. The amount of gas remaining depends upon whether the coal is friable or blocky. Friability appears to relate to the depth of the sample below the surface, fixed carbon percentage, Hardgrove grindability index, and proximity to tectonic disturbance. Friable coals emit nearly 96 pct of the total gas during desorption whereas a blocky coal emits only 60 pct of its total gas. Coalbeds that are ill defined as to their blocky or friable nature must be tested in the laboratory for unambiguous analysis.

Jan 1, 1975

By M. Howard Berliner

"INTRODUCTION During the last 4 months of 1943, the Bureau of Mines engaged in an investigation and exploratory drilling program in the area between the Coughlin and Galena Level mines near the town of Shullsburg, in Lafayette County, Wisconsin. The work was undertaken as part of a general Bureau of Mines investigation of the zinc-producing area of southwestern Wiscon¬sin at a time when an effort was being made to increase the production of metals important to the Nation's war program.The portion of the southwest Wisconsin zinc district in the immediate vicinity of Shullsburg and the Coughlin and Galena Level mines is well mineralized. The principal ore horizon is at shallow depth, and there is evidence that relatively extensive surface mining for lead was done over a period of many years. Underground mining' for lead and zinc has continued to the present time.The Bureau undertook an exploratory drilling program in the area immediately west and southwest of the Coughlin mine workings after thorough preliminary investigations and geologic studies indicated that such work would serve to guide operators in the development of new ore reserves needed for continuance of mining operations in that area."

Apr 1, 1947

By J. R. Katan, J. R. Ball, Peter R. Bannister, F. J. Williams

During the last week in March and the first week in April, 1973, the Naval Underwater Systems Center measured the 76 Hz magnetic field strength (in Wisconsin and Texas) produced by both the elevated and (newly installed) buried Wisconsin Test Facility (WTF) north-south (NS) antennas. The principle result obtained from these measurements is that there is no measurable difference in performance between the WTF buried and elevated NS antennas.

Jan 1, 1973

This U.S. Bureau of Mines (USBM) report conveys the results of an economic analysis of minerals in the West Mojave Management Area (WMMA), including the Desert Tortoise Priority Habitat (DTPH), a proposed special land management area. Undiscovered mineral resources were estimated for the entire WMMA, which totals 8.7 million acres. Known mineral resources were studied for the DTPH, which is an area of 1.2 million acres contained within the WMMA. Federal lands within the WMMA are managed by the Bureau of Land Management (BLM). The WMMA includes Federal, State, and private lands in the western portion of San Bernardino County and the eastern portion of Kern County. The center of the study area is 20 miles northwest of Barstow, California (Figures 1 and 2).

Jan 1, 1993

By C. J. Thompson

This Bureau of Mines study describes the preparation of sulfur compound concentrates boiling from 225° to 400° C, and reports the sulfur types detected in these concentrates by low-voltage mass spectrometry (LVMS). Existing LVMS methods were extended; the procedures described should be generally applicable to high-boiling petroleum distillates and concentrates as a preliminary means of narrowing the number of factions to be considered for more detailed separation and identification studies. The following major sulfur compound constituents of petroleum are indicated by the data: benzothiophenes, dibenzothiophenes, naphthanothiophenes, naphthenobenzothiophenes, and homologs and isomers of these. Cyclic and chain sulfides comprise a significant portion of the gas-oil range sulfur compound types. The presence of some classes of sulfur compounds containing two sulfur atoms per molecule was indicated.

Jan 1, 1966

By A. F. Cohen

When location guidelines are followed in choosing sites for fixed point velocity transducers for use in underground coal mine monitoring, mine air turbulence intensities <11% are generally expected at those sites. The objective of this Bureau of Mines investigation to determine the effect of turbulence intensities <11% on vortex shedding sensors and transducers. Measurements were made at velocity levels of interest for underground coal mine monitoring use (?200, ?500, ?1,000, ?1,500 ft/min). The effect of grid-produced turbulence intensities (2% to ?14%) on the output of vortex-shedding air-velocity transducers was less than ±10%.

Jan 1, 1985

By Wm. W. Odell

This report comprises a brief outline of the experimental cracking of natural gas in a water-gas generator at Louisville, Kentucky, and a discussion of the results obtained. The work was done under a cooperative agreement by the U. S. Bureau of Mines with the Louisville Gas & Electric Co. The re-forming or partial cracking of natural gas is not a new process, but one which has been employed in the manufacture of city gas for a number of years. However, the apparatus used heretofore was not a water-gas generator containing a bed of ignited fuel, but instead it was a plurality of connected chambers containing spaced and arranged checker bricks, with means for heating the bricks and for admitting the natural gas. The procedure previously followed was quite different from that used during the tests at Louisville; likewise the results obtained were different. It is not uncommon for companies distributing natural gas to provide gas-generating equipment for producing manufactured gas which is used, mixed with natural gas, during periods of peak demand. Because this equipment is idle much of the time, in some instances being in use only for a few days a year, some of the gas companies have considered using it, during off-peak periods, in the manufacture of some gaseous products and for carbon black which might he produced and marketed with profit. There is one plant of this kind at Louisville. Kentucky. Its maintenance in condition ready to be operated is necessary because of the limited supply of natural gas and because of the variation in demand. The engineers of the Louisville Gas & Electric Co. considered in particular the possibility of cracking natural gas in a water-gas generator by injecting the gas into the incandescent fuel bed, thereby producing a gas comprised largely of hydrogen (H2) and carbon black, an appreciable amount of which is entrained in the gas as it leaves the generator, Because power and gas are available at low prices, Louisville was believed to be a satisfactory location for a plant which could use hydrogen. It was evident that this method of treating natural gas might directly benefit the gas company by: 1. Lowering, the cost of manufactured gas.

Jan 1, 1930

By Douglas C. Corner

This is the first of a series of papers dealing with modern tunnel-driving methods, compiled in accordance with an outline prepared by engineers of the United States Bureau of Mines and to be published in a series of information circulars by the bureau. This series will supplement a similar and earlier series of papers dealing with mining methods and costs. ACKNOWLEDGMENTS The author desires to express hiss appreciation, of the assistance of A. C. Dennis, manager for the West Construction Co. Contractors, and Franc: E. Winsor, chief engineer for the Boston Metropolitan District mater Supply Commission who furnished much of the data and detailed description of operation appearing in the following pages. C. F, Jackson, mining engineer, United States Bureau of Mines, collaborated in the preparation and arrangement of the text.

Jan 1, 1931