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By Nar S. Dala1, Xianglin Shi, Val Vallyathan

"Electron spin resonance (ESRJ and cytotoxicity measurements were made on newly fractured silica to examine specifically the role of the fracture-induced, silicon-based radicals (Si· and SiO·) and silica-generated hydroxyl (·OH) radicals in the mechanism of the cell membrane damage by silica. The concentration of the Si· and SiO · radicals was controlled through decay processes, thermal annealing, and boiling, while that of the ·OH radicals was varied by using catalase, superoxide dismutase, KMnO, Na;iSeO:y ascorbic acid, and metal ions, and monitored via ESR spectroscopy. The dust's cytotoxicity potential was evaluated by measuring the silica-induced hemolysis and also by determining lipid peroxidation (using linoleic acid). From the comparison of hemolysis and ESR results it is deduced that the radicals play little or no role in the silica-induced hemolysis. However, the lipid peroxidation data indicate that the radicals might be involved in the initiation of an oxidative chain reaction leading to the macrophage membrane damage through lipid peroxidation. INTRODUCTIONThe biochemical mechanism of quartz-related pneumoconiosis is still not fully understood. It is believed, nevertheless, that one event of primary importance is the perturbation of cell membranes by the dust particles (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Parazzi et al., 1968; Reiser and Last, 1979; Shi et al., 1989; Summerton et al., 1977). The ensuing cell: membrane damage unleashes certain lytic enzymes resulting in additional cell injury and eventual fibrosis (Nolan et al., 1981; Summerton et al., 1977). Thus considerable effort is currently being made toward the understanding of the processes by which quartz particles disrupt the membrane of a red blood cell (RBC) or a pulmonary alveolar macrophage (PAM). A simple but important method of evaluating the membrane damage potential of a dust is the hemolysis test (Harington et al., 1971). Even though this test is used routinely for screening dusts for their cytotoxicity potential, the biochemical mechanisms underlying the cell lysis by many dusts, including quartz, is still controversial (Kilroe-Smith, 1974; Singh and Rahman, 1987), and this provided us the impetus for the present undertaking."

Jan 1, 1990

By Spencer P. Howell

One of the important problems in metal mining , tunneling or quarrying is the most economical method of bringing down the ore or rock . The two factors having great influence in determining this are arilling and blasting costs . In considering the efficiency of the explosive used , the diameter of cartridge has always been supposed to play an important part . However , the Bureau's attention has been called to the lack of definite data on the effect of cartridge diameter on the strength and sensitiveness of high explosives . This information is especially valuable to the user of explosives as it assists him to determine what diameter of borehole is most economical . A paper* on "The effect of cartridge diameter on the strength and quickness of high explosives " was submitted to the sub- committee on Drills and Drill Steel of the 24th Annual Convention of the American Mining Congress by Charles S. Hurter , Technical Representative of the E. I. duPont deNemours and Co. In this paper Mr. Hurter points out that the physical characteristics of an explosive most affected by the diameter of cartridge are rate of detonation and sensitiveness to explosion by influence , and that both increase with increase in diameter . As there is a continuing tendency to the use of smaller diameter drill holes in order to lower drilling costs , and as the smaller drill hole requires a smaller diameter of explosive cartridge than larger drill holes do , this paper has been prepared to show the effect the diameter of cartridge will have on the strength and sensitiveness of the high explosives which may be used . Accordingly , the Bureau of Mines , in cooperation with the Institute of Makers of Explosives , has carried out a series of tests to show the effect of cartridge diameter on the strength and sensitiveness of certain high explosives .

Jan 1, 1923

By S. L. May

Investigations by the Federal Bureau of Mines indicate that hafnium and zirconium compounds of acceptable purity can be extracted from Nigerian zircon concentrates. Chlorination and caustic soda fusion techniques were used to extract 85 to 95 percent of the valuable metals from the concentrate. The extracted hafnium and zirconium compounds were purified by recrystallization of the oxychlorides or by formation of complex salts during chlorination. The zirconium-hafnium product of the recrystallization method contained 15 parts per million of uranium, and the product of the salt-complex method contained less than 10 parts per million of uranium. The hafnium was separated from zirconium by solvent extraction methods. A zirconium product containing 0.3 percent hafnium and a hafnium product containing 4 percent zirconium were obtained. At the request of the Atomic Energy Commission (AEC), work was started to develop techniques for processing Nigerian zircon concentrates in commercial installations presently engaged in producing zirconium and hafnium metals from ores. The Nigerian zircon has a high hafnium content, but the presence of uranium and thorium is a problem not normally encountered in processing zircon concentrates.

Jan 1, 1961

By Francis C. Lincoln

"INTRODUCTION In the course of a general investigation of mines and mineral deposits in the Upper Mississippi lead and zinc field, attention of the Bureau of Mines was first directed to the Coker mines area by the presence of large tonnages of old mill tailings containing economically recoverable percentages of lead and zinc. Later, the results of extensive geologic studies of the area were presented to the Bureau of Mines by the Federal Geological Survey, directing attention to the possibility of extending the known ore limits of the area to the north and northeast of the old Coker No. 1 mine workings.With this end in view, the Bureau of Mines undertook a program of churn drilling and sampling. This report describes the work done and presents the data obtained during the period of the Bureau of Mines investigation.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. The Mining. Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, O. C. Ralston, chief, analyzes the samples and makes beneficiation tests."

Apr 1, 1948

By Changwoo Lee, Jan M. Mutmansky

"This paper results from the research at The Pennsylvania State University into establishment of standard procedures for characterization of respirable coal dust performed by the Generic Mineral Technology Center for Respirable Dust and supported by the U.S. Bureau of Mines and the Mining and Mineral Resources Research Institute at The Pennsylvania State University. The research performed within this particular project is oriented primarily toward standard methods of sampling and characterizing respirable coal mine dust underground so that the chemical, physical, and morphological characteristics are known and can be related to the incidence of coal workers' pneumoconiosis (CWP) in Pennsylvania.The research was initiated by con¬ducting a search of the literature to determine what coal and geologic variables may be related to CWP. The effects of coal rank, free silica content, the mass of respirable dust, and the level of trace elements were the major variables studied. It seems to be evident that the free silica content, the rank of coal, and the mass of respirable dust are the major concerns in defining the causes of CWP. However, based on the literature survey, the authors have concluded that verification of the causes of CWP is a multivariate problem and must be analyzed in an appropriate statistical manner.The results of a multivariate analysis of ten trace elements recorded on Pennsylvania coals are presented. Five of these trace elements were found to be of use in differentiating one coalfield from the others. Of these five elements, chromium and zirconium showed a strong positive correlation with the rank of coal while strontium showed a negative correlation.The design of the field sampling work and its application in future research is the final topic discussed. The sampling plan is oriented toward continuous miner sections with eight-stage impactors as the collection equipment. All of the field work will be conducted in the coal measures of the Allegheny Formation and above with both dust and channel samples being collected in the same mines.Coal workers' pneumoconiosis has been an important topic of concern to miners, mining engineers, and epidemiologists for decades. The general cause of the dis¬ease, the inhalation of coal mine dust, is well known, but the specific coal and geologic variables that affect the incidence and severity of the disease are still subject to debate and study. The primary objective of this study is to identify those variables of Pennsylvania coals that contribute to the CWP problem. To accomplish this task, a field sampling program is to be conducted to relate the characteristics of the coal dust, the coal seam properties, and the geologic variables to the occurrence of CWP.The first year of this study has been involved with both a literature review and experimental work oriented toward identification of causal variables related to CWP. The results of this work are presented here along with plans for implementation of the findings in future research.The previous studies of CWP causal variables have been conducted by scientists, engineers, and medical personnel. Many different types of studies have been performed with emphasis on interpreting the effects of dust mass concentration, mineralogy of the coal, the rank of the coal, and trace element concentrations upon the incidence of CWP in various coalfields. Most of the research has been conducted during the last two decades, with the British Isles, West Germany, and the United States being the primary countries involved.The review of the literature was conducted to determine which variables are likely to warrant further study in Pennsylvania. Previous research studies have related CWP to free silica and other mineral content, the rank of coal, the mass of dust in the working place, and the trace elements in the coal and lung dust. In the following sections, each of these topics will be discussed and analyzed."

Jan 1, 1988

Objective: To provide a safe, practical, cost-effective method for measuring coal rib thickness during highwall mining.

Jul 1, 2008

By R. August Heindl

[A proposes process for recovering manganese from open-hearth steel-plant slogs is indicated by the flow diagram shown in figure 1. Investigation of the process, the laboratory development of which was reported previously,4/ was expanded to a larger scale. Mixtures of flush slags and limestone were proportioned to have molar [SiO2] ratios of 1.5 to 2.2 and were fired at temperatures up to 2,400° F. In an oxidizing atmosphere. This produced clinker consisting principally me various combinations of the oxides of manganese, iron, aluminum, and magnesium aloe with a dicalcium silicate phase containing the phosphorus. Some tests were made with a continuous sintering machine of the traveling-grate type, but a rotary kiln was the most satisfactory apparatus for this operation. Material was fed at 150 to 200 pounds per hour after first being agglomerated either on the sintering or else binder extruding and drying finely ground mixture of the sing, limestone, binder, and water. Tests with slag; from tree different source indicated overkill manganese recoveries of 65 to 80 percent by ammoniacal-ammonium-carbonate leaching.]

Jan 1, 1955

By Raja V. Ramani

Productive and beneficial use of reclaimed surface-mined land is a concern of industry, government, and the general public. An investigation was conducted of current mined-land planning practices to aid in the development of a procedure for evaluating postmining land use potentials. This investigation considered both the industry and public planning approach to mined-land planning. It included a detailed review of the impact of regulation, factors that determine land use, and current site planning methods employed by the mining industry. The methods of this investigation included three in-depth case studies of surface mines in the eastern, central, and western United States. A site planning pro-cess has been developed and applied to the surface mine case studies to evaluate the economic, environmental and social impacts of postmining land use alternatives. In add it ion, guidelines are proposed to enhance the cooperation between local land use planners and surface mine planners, as well as to improve comprehensive planning with regard to mineral resources at the local and regional level.

Jan 1, 1983

By Launa Mallett

This training material focuses on the content of emergency warning messages. Research has shown that when an emergency occurs, people often do not get the information they need for the purpose of taking appropriate action. This safety talk presents a procedure, using mental cues that can be used by senders and receivers of emergency warnings.

Jan 1, 1999

By Launa Mallett, PhD, Charles Vaught, PhD

This training material focuses on the content of emergency warning messages. Research has shown that when an emergency occurs, people often do not get the information they need for the purpose of taking appropriate action. This safety talk presents a procedure, using mental cues that can be used by senders and receivers of emergency warnings.

By Oliver Bowles

This report covers the character, properties, origin, occurrence, and uses of the traprocks and describes briefly the methods and equipment employed in quarrying and preparing them for market. Production of traprock occupies an important place in industry. In 1960 the output in the form of crushed stone reached nearly 58 million tons valued at $87 million. Traprocks are also shaped into blocks of dimension stone for monuments, building construction and decoration, and specialized products such as surface plates.

Jan 1, 1963

By Oliver Bowles

This report covers the character, properties, origin, occurrence, and uses of the traprocks and describes briefly the methods and equipment employed in quarrying and preparing them for market. Production of traprock occupies an important place in industry. In 1960 the output in the form of crushed stone reached nearly 58 million tons valued at $87 million. Traprocks are also shaped into blocks of dimension stone for monuments, building construction and decoration, and specialized products such as surface plates.

Jan 1, 1963

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

"Electron spin resonance (ESR) and cytotoxicity measurements were made on newly fractured silica to examine specifically the role of the fractured-induced, siliconbased radicals (Si· and SiO·), and silica-generated hydroxyl (·OH) radicals in the mechanism of the cell membrane damage by silica. The concentration of the Si· and SiO· radicals was controlled through decay processes, thermal annealing, and boiling, while that of the ·OH radicals was varied by using catalase, superoxide dismutase, KMnO4, Ha2seO3, ascorbic acid, and metal ions, and monitored via ESR spectroscopy. The dust's cytotozicity potential was evaluated by measuring the silica-induced hemolysis and also by determining lipid peroxidation (using linoleic acid). Prom the comparison of hemolysis and ESR results it is deduced that the radicals play little· or no role in the silica-induced hemolysis. However, the lipid peroxidation data indicate that the radicals might be involved in the initiation of an oxidative chain reaction leading to the macrophage membrane damage through lipid peroxidation. INTRODUCTIONThe biochemical mechanism of Quartz-related pneumoconiosis is still not fully understood. It is believed, nevertheless, that one event of primary importance is the perturbation of cell membranes by the dust particles (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Parazzi, et al., 1968; Reiser and Last, 1979; Shi et al., 1989; Summerton et al., 1977). The ensuing cell-membrane damage unleashes certain lytic enzymes resulting in additional cell injury and eventual fibrosis (Nolan et al., 1981; Summerton et al., 1977). Thus considerable effort is currently being made towards the understanding of the processes by which quartz particles disrupt the membrane of a red blood cell (RBC) or a pulmonary alveolar macrophage (PAM). A simple but important method of evaluating the membrane damage potential of a dust is the hemolysis test (Harington et al., 1971). Even though this test is used routinely for screening dusts for their cytotoxicity potential, the biochemical mechanism underlying the cell lysis by many dusts, including quartz, is still controversial (Kilroe-Smith, 1974; Singh and Rahman, 1987), and this provided us the impetus for the present undertaking."

Jan 1, 1989

By Marcia L. Harris

Toxic fumes produced by detonating explosives in surface mining and construction operations pose potential hazards to workers and the public. Blasting operations produce both toxic and nontoxic gaseous products; the toxic products are mainly carbon monoxide (CO) and the oxides of nitrogen (NOx). Since 1988, there have been 17 documented incidents in the United States and Canada in which carbon monoxide (CO) is suspected to have migrated through ground strata into occupied enclosed spaces as a result of proximate trench blasting or surface mine blasting. These incidents resulted in 39 suspected or medically verified carbon monoxide poisonings as well as one fatality. At worst people may be fatally poisoned and the least to be expected is increased public objections to blasting. Local and state agencies could demand a cessation of the blasting requiring more expensive mechanical means to break the rock. This paper discusses the most feasible means of preventing CO migration, mitigating CO that has migrated, and detecting CO in an underground enclosed space and may help reduce the exposure of unsuspecting area residents to carbon monoxide and help prevent the implementation of unnecessary regulations and limitations on blasting. Single-hole shots and small-scale multiple-hole blasts were performed that indicate promising means of prevention and mitigation.

Jan 1, 2008

By Robert E. Manning

The Federal Coal Mine Health and Safety Act of 1969 has placed stringent limitations on the noise levels in which employees may work. This act can result in both increased labor costs because of noise-exposure time limitations and in high capital costs for modification of present equipment, and the design of new equipment, to comply with the law. The development of new noise-control systems is thus of immediate interest to industry. A current Research program at U. S. Steel is aimed at developing methods of controlling both the exhaust-air noise and the mechanical noise of a Stoper drill, a pneumatic percussive tool used for roof-bolting purposes in coal mines which has an approximate air consumption of 100 cubic feet per minute. This program is being performed under a contract between USS Engineers and Consultants, Inc. and the Pittsburgh Mining and Safety Research Center of the U. S. Bureau of Mines. In previous work at U. S. Steel, kidney-shaped mufflers were designed that wrap around the air leg of the drill for control of the exhaust noise. These mufflers were designed with the aid of a digital computer program that predicts the acoustic performance of mufflers.

Jan 1, 1975

By Richard D. Miller

This Bureau of Mines publication contains analyses and related source data for 224 natural as samples from 18 States. Of the total, 191 sam¬ples were collected during calendar year 1981. The remaining 33 samples were collected during previous years, but releases, granting permission to publish were not received until 1981. All samples were obtained and analyzed as part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by the mass spectrometer and special helium apparatus described previously (1-2).3 The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the general public. Twenty-five publications have presented the results of 12,827 gas analyses made prior to 1981. The first three bulletins (1-3) contain analyses and related data on 5,218 gas samples collected from 1917 through 1960; these bulletins have been supplemented annually by information circulars (4-17, 19-24) containing 7,609 analyses of samples collected since 1960.

Jan 1, 1982

By Aner W. Erickson

Magnetite iron deposits on Tolstoi Mountain were examined as part of the investigations by the Bureau of Mines of iron and copper ores on Prince of Wales Island. The Tolstoi Mountain project was a part of a program for investigating mineral deposits in Alaska, under the general supervision of R. S. Sanford, acting branch chief.

Jan 1, 1948

By Liming Yuan

In order to reduce fire hazards caused by spontaneous combustion in longwall gob areas, a computational fluid dynamics (CFD) study is being conducted by National Institute for Occupational Safety and Health (NIOSH) to simulate the spontaneous heating of coal in longwall gob areas. A CFD model was first developed to model the spontaneous heating process in a two longwall panel district using a bleeder ventilation system with a stationary longwall face. The spontaneous heating is modeled as the low-temperature oxidation of coal in the gob using kinetic data obtained from previous laboratory-scale spontaneous combustion studies. Heat generated from coal oxidation is dissipated by convection and conduction, while oxygen and oxidation products are transported by convection and diffusion. CFD simulations were then conducted to model the spontaneous heating in longwall gob area with a bleederless ventilation system. A single longwall panel with a bleederless ventilation system was simulated. The effect of gob permeability on the spontaneous heating was also investigated.

Jan 1, 2009

By William C. Miller

This report describes investigations by the Bureau of Mines designed to establish the noise level and spectrum of various types of pneumatic rock drills and to furnish information that would be useful in conducting sound measurements in mining environments and in reducing the noise generated in pneumatic drilling. These investigations show that (1) the noise generated by the drills in the frequencies below 100 cps is caused by the impact of the piston and drill steel, in the frequency range between 100 and 2,000 cps by the exhausting of air from the ports, and in the frequencies above 2,000 cps by the resonant frequencies of steel drill parts and of drill steel; (2) satisfactory instruments and instrumentation systems are available for field and laboratory measurements; (3) reliable sound measurements can be made in mining environments; and (4) devices can be developed that will abate the noise.

Jan 1, 1963

By T. H. Dubaniewicz

Fiber-optic technology is progressing rapidly, including the development of fiber-optic sensors for many applications. These sensors have the advantages of high sensitivity, light weight, small size, high bandwidth, and freedom from electromagnetic influences. The U.S. Bureau of Mines is investigating the use of fiber-optic technology to monitor mine atmospheres. This report describes a methane monitor based on differential absorption of infrared light. The monitor can detect methane concentrations as low as 0.2 vol pct as far away as 2 km via fiber-optic cable. The upper range is 100 vol pct methane. Since the system requires no electrical power within the mine, it is intrinsically safe.

Jan 1, 2010