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By W. E. Wallace, V. Castranova, F. Saus, D. Bates, C. A. Hill, V. Vallyathan, M. J. Keane

"Two in vitro systems are being developed to model initial stages in the interaction of respired dusts with the acinar region of the lung. Incubation of quartz and kaolin with dipalmitoyl glycerophosphorylcholine, a major component of pulmonary surfactant, suppresses the prompt C)1otoxicity of both dusts as measured by in vitro enzyme release from pulmonary macrophages or assay by erythrocyte hemolysis. Additional data is presented to quantitate the detoxification of quartz and kaolin by dipalmitoyl lecithin. Subsequent incubation of lecithin treated dusts with phospholipase enzymes results in partial to complete restoration of the assayed cytotoxic potentials, dependent on the lipase activity applied, the incubation time, and the mineral. Restored cytotoxic potential is due to removal of the prophylactic lecithin surface coating and/or due to residual lysolecithin which is produced by the partial enzymatic digestion of lecithin. Data is presented on the contribution of each mechanism to the restored toxicity. Again, this is dependent on the mineral used, the lipase activity applied, and digestion time. Additionally, a system is under development to challenge pulmonary macrophages in culture with native and surfactant treated dusts. A preliminary test of the dipalmitoyl lecithin - quartz rabbit pulmonary macrophage system is presented to illustrate the method.IntroductionRespirable quartz dust exposure is known to cause librotic lung disease; respirable clay dust exposure is less likely to do so as indicated by epidemiologic data on occupational exposures and by animal model studiesP·7) The hypothesis that damage to pulmonary macrophages in the acinar region of the lung by respired dusts is an early event in the disease process requires consideration because kaolin clay and quartz dusts are comparably cytotoxic to pulmonary macrophages in vitro.(3•9)"

Mar 1, 1989

By J. Douglas Causey

In 1986, at the request of the Bureau of Land Management, the U.S. Bureau of Mines studied the 7,940-acre Southern Otay Mountain Wilderness Study Area (CA-060-029), and the 5,750-acre Western Otay Mountain Wilderness Study Area (CA-060-028) in order to evaluate their mineral resources. The wilderness study areas are located in San Diego County, CA, about 20 miles southeast of San Diego. No mineral resources were identified in the Southern or Western Otay Mountain Wilderness Study Areas, based on literature, field observations, and sample results. The wilderness study areas are underlain by a complex blend of Late Jurassic, moderately metamorphosed sedimentary and volcanic rocks. Evidence of mineralization is not obvious.

Jan 1, 1987

By L. H. Wullstein

Bureau of Mines research on methods for reclaiming land disturbed by the minerals sector of the economy has produced a specific procedure for effectively germinating seed of Indian ricegrass, a drought-tolerant plant valuable for reclaiming arid and semiarid sites. This report describes the procedure which consists of acid-treating the seed followed by temperature and light cycling treatments. Use of the procedure resulted in an average germination rate of 29 percent, ranging from 18 to 56 percent. Seed subjected to long cold treatment but with acid treatment yielded an average germination rate of 9.2 percent, ranging from 6.6 to 14.7 percent. Untreated seeds (controls) gave germination rates less than 0.1 percent.

Jan 1, 1979

Reduce injury to people or damage to equipment when a scheduled production blast is detonated. Approach The essential elements of an effective blast area security system were identified through case studies of five mining operations where the blast area guarding practices were considered to be superior to those generally found in the industry. These elements were used in making recommendations for improved blast area safeguarding practices. Background The blast area security system is a means by which the mine operator prevents injury to people or damage to equipment when blasting is performed. Analysis of blasting accidents showed that most blasting accidents occur during scheduled blasting and are due to inadequate blast-site security. Factors contributing to the system's breakdown are failure to clear the blast zone, inadequate guarding. and failure of personnel to follow instructions, retreat to a safe location, and/or take adequate cover. Mine personnel, visitors and even trespassers can inadvertently wander into a blasting zone unless proper procedures exist to ensure that all personnel are cleared from the blast zone and kept safely away until after blasting IS completed. Statistics show that the blaster is the miner most frequently injured In these accidents.

Jan 1, 1986

Improve underground long-hole drilling efficiency and safety by developing a lightweight, easily transportable drilling pust that can be adjusted to fit a range of mine opening heights. Background Standard one-piece commercially available steel posts weigh approximately 10 pounds per foot. Transporting these posts underground and carrying them over obstacles and through small mine doors is very difficult. Because the length of a one-piece post cannot be adjusted, variations in mine opening height at the drilling site must be accommodated. This is accomplished by stacking several wooden blocks to form a base for the post, resulting in a dangerously unstable drilling setup. The only alternative to this unstable setup is to obtain a longer post. There problems can be reduced by the use of a two-piece telescoping aluminum post having a 3-foot adjustment range in 6-inch increments. The two-piece extendable post will be easy to transport and carry underground. It will fit any opening height within its adjustment range. One large wooden block is used as a base and one cap block is used at the top to bear against the mine roof. This arrangement results in a stable, rigid setup.

Jan 1, 1990

By Stephen C. Tadolini, Thomas M. Barczak

Western mines have had limited choices for standing support. Wood cribs were often too soft and unstable. The introduction of the Can support in the early 1990’s provided a very effective alternative and remains the dominant form of tailgate support. Water-filled prestressing cells are now used to cap the Can and preload it to provide an active roof load. The Cluster Prop, consisting of three timber wedge props bundled together, provides more capacity than an equivalent sized Can support and improves transport efficiency. However, the Cluster Prop is less stable and does not maintain a consistent load throughout its loading profile. Pumpable roof supports are another alternative support, but they have not been proven in high deformation environments. Alternative supports are also being used in longwall recovery operations. These include the Rocprop and Omni Prop, which are extendable support systems. They also provide active roof loading which can be beneficial in these applications. Specialty supports, such as the Sand Prop and Spider Prop, have also been introduced into western longwall operations. This paper compares the performance characteristics of these various support systems.

By Edward L. McHugh, Charles Sabine, Louis J. Denes, Jami M. Girard, Peter Metes

The Spokane Research Laboratory, National Institute for Occupational Safety and Health, is investigating various remote sensing technologies as possible tools to detect, monitor, and mitigate hazardous situations in surface mines that could lead to catastrophic slope failure. Promising technologies include a field-portable spectro-polarimetric imager and a stationary interferometric radar device. Field tests were conducted of a prototype visible and near-infrared spectro-polarimetric imager (SPI) built at the Carnegie Mellon Research Institute. The SPI employs anacousto-optical tunable filter (AOTF) to control wavelength, a phase retarder to measure polarization signatures, and a digital camera and computer to capture data. Images obtained at the Mountain Pass and Castle Mountain mines in southeastern California showed that the instrument is capable of obtaining hyperspectral images of highwalls, outcrops, hand samples and drill core in the field. We have retrieved spectra from Mountain Pass images that closely match those of bastnaesite and have had some success in classifying images. Although radio frequency noise in the data limited spectral classification of imagery, we project that careful alignment of the AOTF should minimize the noise and greatly improve classification.

By D. L. Paulson

Electric furnace smelting of blister copper directly from copper precipitates (cement copper) was investigated by the Federal Bureau of Mines. Copper concentrations in five different lots of cement copper in the investigation ranged from 62.5 to 82.5 wt-pct. Laboratory-scale smelting tests were made in a 50-kva electric-arc furnace to establish the reductant and flux requirements. Best recoveries were realized by adding 60 pct of the carbon required to combine with the contained oxygen in the cement copper. Operating parameters established during the laboratory-scale smelting tests were used successfully in smelting 20 tons of cement copper during 12 pilot-scale tests in an 800-kva electric-arc furnace. Over 98 pct of the contained copper was recovered as blister-grade metal. The projected energy consumption for a commercial-size furnace was 380 kwhr per ton of cold charge.

Jan 1, 1978

By James P. Bennett

The Bureau of Mines investigated the role of imported natural flake graphite in dolomite-carbon refractories used in steelmaking processes. Fundamental engineering data were obtained to enable the evaluation of substitute materials. Changes in oxidation resistance (2,000° F), hot strength (2,750° F), and deformation under load (2,7500 F) caused by 10-wt-pct additions of five different kinds of natural flake graphite and increasing quantities (0 to 30 pct) of a 90-pct-carbon natural flake graphite were studied. Results indicated that carbon purity of 10-wt-pct-graphite additions did not influence hot strength or deformation under load. When the quantity of 90-pct-carbon graphite addition varied between 0 and 30 wt pct in a dolomite-carbon brick, hot strength was highest and de-formation under load lowest with 10-wt-pct additions. As hot strength test temperature was increased from 5000 to 2,750° F, the strength difference observed between 0-and 30-wt-pct additions of a 90-pct-carbon graphite became smaller. Additions of a boron-treated graphite caused significantly higher strength and lower deformation under load at high temperatures, while an addition of ball clay significantly reduced strength and increased deformation.

Jan 1, 1987

By Raymond B. Ladoo

The uses for which ground talcs are suited closely depend upon their physical and chemical properties , but , in spite of this fact , little scientific investigation has been made in order to devise quick and accurate tests for the determination of these properties . The chemical properties of talc are inherent and may not be altered or modified except by selective mining or by chemical processes not practical in the present status of the industry . However , the determination of chemical properties is not so important , for most uses , as of physical properties , although sometimes certain chemical characteristics are perhaps unduly insisted upon by chemists in some industries . Physical properties are dependent both upon mineralogical characteristics and upon methods of grinding and sizing and may thus be partly changed or modified by changes in practice . There is so little known of the chemistry and physics of the various processes in which talc is used that the purchase and sale of talc is governed more by rule- of- thumb methods dependent upon individual opinion and often , prejudice , than by accurate , standard tests . This not only causes unwarranted price fluctuations , but injures both the producing and consuming industries by creating false ideas of the suitability of talc for various uses . It thus seems important that present tests be standardized and made uniform for the whole industry , and that new tests devised to fill the existing gaps .

Jul 1, 1920

By John B. Shutack

In an effort to improve the performance of the explosive-anchored rock bolt, the Bureau of Mines studied the effect of the detonation velocity of the explosive and type of charge (linear or nonlinear) on the fracturing tendency of the anchor tube. Also, different types of tubing were compared to determine the one most suitable for use as an anchor tube. The Bruceton up-and-down method was applied in tests in which steel shooting blocks having boreholes ranging from 1-3/8 to 2-1/8 inches in diameter were used. Of the four types of tubing evaluated, a welded A-178 tubing that was drawn over a mandrel and renormalized gave the most promising results. The A-179 seamless tubing that is normally used with the explosive bolt was the most inferior. Both types, however, gave significantly better anchorage than the conventional shell when tested in both laboratory and underground experiments. Within the range of velocities studied (5,000 to 7,000 m/sec), the type of explosive showed no significant effect on anchor-tube performance. In general; linear explosive charges provided better anchorage than nonlinear charges.

Jan 1, 1968

By EINAR M. ARENTZEN

This information circular. deais primarily with an engineering descrip- tion of a type of longwall cutting and loading machine developed by Eick- hoff Maschinenfabrik, Bochum, Germany..: This machine is supposed to have been developed and tested during the latter part of 1941 and early 1942. The only source of information is con- tained in certain literature and engineering data, with drawings which were acquired by the Allied Military Authorities when Germany was occupied; and the information will have to be limited because the writer has not seen the machine in the factory or in operation. However, the information may be of interest to the coal-mining industry in this country, and for this reason our Government has decided to publish the data procured so far. The Eickhoff cutting and loading machine is particularly suitable for the longwall mining system. It can only be used under that type of mining system and is not suitable for the more common type known in this country as room-and-pillar work. The material for the description of the machine and its operation was compiled and translated from German drawings and operating instructions. These detailed drawings and instructions are on file with the Bureau of Mines and are available for inspection by any responsible person interested in the details of the construction of the machine.

Dec 1, 1946

By Laxman S. Sundae

In the vast majority of American coal mines, roof bolt holes are drilled dry, mainly because of mine operator concern with the spent water creating adverse working conditions. Wet drilling, however, can increase drilling rates and the effective lifetime of the drill bits used. This study, carried out as part of an ongoing cooperative research program between the U.S. Bureau of Mines and the University of Missouri-Rolla, shows that the large volumes of water conventionally used in wet drilling are not necessary, and the performance benefits from wet drilling can be achieved with total volume flows on the order of 0.4 L per hole. This conclusion is validated based on the measured respirable dust generated in drilling Berea sandstone. The results are confirmed using a variety of bit shapes, which are also shown to have a significant effect on penetration rate.

Jan 1, 2010

By J. W. Miller

This report deals with upgrading of the coal reserves of Raleigh County, VI. Va., to metallurgical standards. The data on samples herein correctly show the characteristics of the bed at the point where sampled and are used to indicate the general quality of the bed in the county. The principal results and conclusions are: 1. Raleigh County contains large reserves of high-quality, high-, medium-, and low-volatile coals. 2. The principal beds from which an increased amount of coal is expected to be mined in the future are: The Eagle, Powellton, No. 5 Block, Hernshaw, Fire Creek, and Pocahontas No.6.

Jan 1, 1954

By W. K. Tolley

This report presents data collected during research by the Bureau of Mines on corrosion of grinding media. Corrosion rates of eight alloys commonly used in grinding media were tested in synthetic mill water using an ultrasonic grinding device especially designed for this work. Electro-chemical measurements showed variations in corrosion rates for these alloys between 9.8 mpy for medium-carbon steels and 0.14 mpy for high chromium white irons. Bureau data are discussed along with data from the literature to indicate that corrosion causes less than 10 pct of the wear of grinding media in commercial grinding mills. A comparison of corrosion rates for various types of grinding media shows that alloying elements and electrochemically active inclusions in steel affect the corrosion behavior of the media.

Jan 1, 1984

By John Nagy, Hylton R. Brown, Irving Hartman

"INTRODUCTION The tests described in this publication were planned to provide information on the explosibility of metal-powder dust clouds. This subject has become increasingly important because of the large quantity and variety of metallic powders now used for military and industrial purposes. To provide the increased amounts of metallic powders needed in the manufacture of munitions and to supply the demand created by the rapid growth of powder metallurgy, existing metal-powder plants have been enlarged, production schedules accelerated, and new plants erected. In some cases new methods of producing metal powders have been developed. This increased production and the development of new manufacturing methods have caused an increase in the number of metal-powder fires and explosions, with accompanying heavy loss of life and property. These have emphasized the need for information on methods of providing protection against hazards inherent in the production and handling of powdered metals. This paper gives results of laboratory inflammability and explosibility tests made to April 1, 1943, and is a progress report. Many descriptive details have been omitted purposely; they will supplied in a later publication, expected to be a Bureau of Mines bulletin."

Oct 1, 1943

By Bruce D. Hanson

The Bureau of Mines conducted a series of experiments using four different coal types to determine the effect of attack angle and symmetric bit wear on airborne respirable dust (ARD) generated by point-attack bits and in energy consumption. Neither had a significant effect on ARD at the 95-pct confidence level, but bit wear had a significant effect (95 pct confidence) on specific energy (energy per gram of cut coal) for three coal types, Depth of cut was the most significant factor affecting ARD and specific energy.

Jan 1, 1979

By Synthia N. McIntosh

The U.S. Bureau of Mines investigated the feasibility of using ammonium carbamate (NH2CO2NH4) leaching to recover manganese from steel plant slag. This investigation showed that treatment of the slag in hydrogen prior to leaching enhanced manganese extraction. Up to 80 pct of the manganese and 50 pct of the iron could be extracted from a silicon steel slag that had been pretreated in hydrogen at 700° C. Two 4-h leaching stages conducted at ambient temperature with a solution containing ammonia and carbon dioxide dissolved manganese and iron as their carbamate complexes. Heating the pregnant solution to 65° to 85° C decomposed the complexes and precipitated the metals as insoluble carbonate salts. Ammonium carbamate leaching of other slags from several steelmaking plants produced lower manganese extractions, which suggests that the method cannot be applied satisfactorily to all steelmaking slags

Jan 1, 2010

By W. L. Staker

Alternatives were developed to the conventional ammoniacal carbonate leaching-steam stripping procedure for recovering copper as an oxide from contaminated scrap metal. By entraining air bubbles in the leach solution, the copper dissolution rate was increased to 1.5 g/in2 of copper surface per hour, compared to 0.5 g/in2/hr produced by conventional agitation in stirred tanks. Using entrained nitrogen gas bubbles for agitation in conjunction with powdered sulfur not only resulted in rapid dissolution but also simultaneous precipitation of the copper from solution as a high-grade cuprous sulfide.

Jan 1, 1971

By Edward A. Barrett, Launa Mallett, Charles Vaught, Kathleen M. Kowalski, Michael J. Brnich, Lynn L. Rethi, Robert Randolph, William J. Wiehagen

The goal of the Pittsburgh Research Laboratory's training research is to explore the relationship between valid instruction and improved worker performance. Studies summarized in this paper include: (a) the development and assessment of training techniques that strengthen miners' ability to act competently in emergencies; (b) investigations of classroom simulations that enhance the perceptual, judgment and decision making skills of workers confronted with mine hazards; and (c) field studies of the linkages between financial investments in occupation at skills training and measurable outcomes.' The authors maintain that better ties between training and performance will aid long-term human resource development. The best way to establish this connection is through the use of objective and reliable data.