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By Lon D. Santis

This paper presents data and theorem to calculate the risk of experiencing undesirable lightning related events while blasting or while engaged in other lightning sensitive activities. The paper provides an overview of lightning hazards in blasting operations and a brief history of lightning related blasting accidents. Lightning continues to be the primary cause of premature initiations of explosives in mining, on average, over two such incidents are reported to the Mine Safety and Health Administration (MSHA) each year. The energy contained in lightning discharges and how this energy sets off explosives in mining is presented. Three categories of lightning warning methods: public media, lightning detectors, and atmospheric electrostatic field measurement are discussed. The remainder of the paper presents recently acquired data on the spatial characteristics of lightning development. This data is used to estimate the risk assumed by blasters under certain conditions. Risk estimations are made for electric and nonelectric blasting if persons are evacuated when cloud-to-ground (c-g) lightning approaches within a certain distance. For example, about 0.6% of all c-g lightning strikes have no other c-g lightning strikes within 25 miles in the previous 30 minutes. The paper shows that a typical blaster using nonelectric initiation in a high lightning density area with a 100% accurate lightning detector set to alarm at 25 miles would have a lightning caused unplanned detonation every 14,000 years

By Robert H. Peters

Are the safety rules in your work place effective? Do supervisors enforce them as they should? Do supervisors abide by these rules? Safety rules are an important aspect of many company safety programs, particularly if employees must work in an intrinsically hazardous environment such as a coal mine. However, for various reasons, supervisors sometimes fail to enforce safety rules (Arvey & Jones, 1985; Hartshorn, 1998). This paper presents some findings obtained from interviews with coal miners about why supervisors sometimes fail to enforce an important mine safety rule. It also contains a few suggestions addressing what could be done to help supervisors perform this job function more effectively.

By Theodore M. Katz, W. Stephen Brightwell, David E. LeGrande, Joseph J. Hurrell, Jane A. Lipscomb, Nancy Lessin, Lawrence R. Murphy, Michael J. Colligan, Steven L. Sauter, Richard A. Lippin

Revolutionary changes in the organization of work have far outpaced our knowledge about the implications of these changes for the quality of working life and for safety and health on the job. This gap in knowledge is one of the 21 priority areas for research under the National Occupational Research Agenda (NORA)—a framework crafted by the National Institute for Occupational Safety and Health (NIOSH) and its partners to guide research into the next decade. This report was developed under NORA as the first attempt to develop a comprehensive research agenda for investigating and reducing occupational safety and health risks associated with the changing organization of work. Research and development needs identified in the agenda include (1) improved surveillance mechanisms to better track how the organization of work is changing, (2) accelerated research on safety and health implications of the changing organization of work, (3) increased research focus on organizational interventions to protect safety and health, and (4) steps to formalize and nurture organization of work as a distinctive field in occupational safety and health.

Jan 4, 2002

By X. N. Hu, X. Shi, V. Vallyathan, N. S. Dalai

"Although silicosis has been studied extensively, the mechanism is still not fully under stood. Experiments do provide evidence that the actions of unique properties of silica surface on the cell membrane are the starting point of silicotic processes. This paper summarizes literature on chemical properties of silica surface, and the effect of particle size on silica toxicity. This paper also discusses the ways in which silica dusts are thought to interact with the cell membrane, with emphasis on freshness, hydrogen bonding, and free-radical interactions.INTRODUCTIONSilicosis is a debilitating pulmonary disease that afflicts persons (miners, foundry workers, ceramic workers, heavy construction workers, etc.) who chronically inhale silica-containing dusts (Schepers, 1960; Silicosis and Silicate Disease Committee, 1988). Since silica is second only to oxygen in weight percentage of the earth's crust (about 28%) and is found in an enormous diversity of minerals, it is natural that silicosis is one of the Major industrial health hazards all over the world. Although silicosis has been studied extensively, the mechanism by which the dusts exert their toxic actions on cells and the processes by which these-actions progress to fibrogenesis are still poorly understood. The biological characteristics of the dusts are largely unknown, although it is suggested that the dust size, shape, surface charge, roughness, surface chemical composition, trace metal content, and crystallinity; dose of silica in the ambient air of the workplace; duration of exposure; genetic variation in exposed sub¬jects; personal respiratory patterns; and presence of any coexisting dis¬ease (such as tuberculosis or rheumatoid arthritis) all influence the ex¬pression of silicosis (Koskinen et al., 1983; Noweir et al., 1980; Raask and Schilling, 1980; Reiser and Last, 1979; Thorne et al., 1985; Wolff et al., 1981). The actual biochemical mechanisms through which these factors operate are still unclear. However, the experiments do provide evidence that the actions of certain unique properties of silica surface on the cell membrane are the starting point of the silicotic process (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Marks, 1957; Parazzi et al., 1968; Reiser and Last, 1979; Summerton et al., 1977). This article summarizes literature on chemical properties of silica dusts and how silica dusts are thought to interact with the cell membrane, with emphasis on hydrogen bonding and free-radical interactions."

Jan 1, 1989

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

"Although silicosis has been studied extensively, the mechanism is still not fully understood. Experiments do provide evidence that the actions of unique properties of silica surface on the cell membrane are the starting point of silicotic processes. This paper summarizes literature on chemical properties of silica surface, and the effect of particle size on silica toxicity. This paper also discusses the ways in which silica dusts are thought to interact with the cell membrane, with emphasis on freshness, hydrogen bonding, and free-radical interactions.INTRODUCTIONSilicosis is a debilitating pulmonary disease that afflicts persons (miners, foundry workers, ceramic workers, heavy construction workers, etc.) who chronically inhale silica-containing dusts (Schepers, 1960; Silicosis and Silicate Disease Committee, 1988). Since silica is second only to oxygen in weight percentage of the earth's crust (about 28%) and is found in an enormous diversity of minerals, it is natural that silicosis is one of the major industrial health hazards all over the world. Although silicosis has. been studied extensively, the mechanism by which the dusts exert their toxic actions on cells and the processes by which these actions progress to fibrogenesis are still poorly understood. The biological characteristics of the dusts are largely unknown, although it is suggested that the dust size, shape, surface charge, roughness, surface chemical composition, trace metal content, and crystallinity; dose of silica in the ambient air of the workplace; duration of exposure; genetic variation in exposed subjects; personal respiratory patterns; and presence of any coexisting disease (such as tuberculosis or rheumatoid arthritis) all influence the expression of silicosis (Koskinen et al., 1983; Noweir et al., 1980; Raask and Schilling, 1980; Reiser and Last, 1979; Thorne et al., 1985; Wolff et al., 1981). The actual biochemical mechanisms through which these factors operate are still unclear. However, the experiments do provide evidence that the actions of certain unique properties of silica surface on the cell membrane are the starting point of the silicotic process (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Marks, 1957; Parazzi et al., 1968; Reiser and Last, 1979; Summerton et al., 1977). This article summarizes literature on chemical properties of silica dusts and how silica dusts are thought to interact with the cell membrane, with emphasis on hydrogen bonding and free-radical interactions."

Jan 1, 1989

By M. Zaki El-Sabban

Tables of chemical thermodynamic properties for the ideal gas state from 0° to 1,000° K are reported for eight alkanethiols, three cycloalkanethiols and arylthiols, six thiaalkanes, two dithiaalkanes, three thiacycloalkanes, and three thiophenes. They are based on current physical and thermochemical constants and definitions, reliable vibrational assignments, and the latest insights into molecular structure and energetics.

Jan 1, 1970

By Donald W. Scott

Chemical thermodynamic properties for the ideal gas state from 0 to 1500 K are tabulated for all of the alkane hydrocarbons through C10. These properties are based on correlations of the extant data for the entropy, vapor heat capacity, and enthalpy of formation of individual alkanes and the equilibrium constants of alkane isomerization reactions.

Jan 1, 1974

By W. I. Nissen

As part of its program to provide technology for reducing undesirable environmental impacts of mineral processing operations, the Bureau of Mines developed the citrate process for desulfurizing industrial stack gases that contain from 0.1 to 2 vol pet S02. In this regenerable flue gas desulfurization (FGD) process, S02 is absorbed from cleaned and cooled industrial flue gas with a citric acid-sodium citrate solution. The absorbed S02 is subsequently reacted with H2S to precipitate marketable elemental sulfur and regenerate the solution for recycle. Laboratory investigations of process parameters provided information for designing larger scale continuous operations. Information gathered from operation of two pilot plants, one at a copper smelter and one at a lead smelter, confirmed the laboratory results. Data were obtained for design and construction of a commercial-sized demonstration plant at the George F. Weaton Power Station, Monaca, PA. A preliminary operation of the plant was demonstrated, under a cost-sharing Bureau-industry contract. This bulletin describes the citrate process and gives results of the laboratory, pilot plant, and demonstration plant studies, as well as corrosion investigations.

Jan 1, 1985

By Launa Mallett, Charles Vaught, Michael J. Brinich

The lack of good communication is a very real problem in mine emergencies. Sometimes critical information is not communicated to those who need it to make decisions. At other times, those on the receiving end of a warning do not think to ask the right questions. What happens in underground coal mine fires is a case in point. The authors interviewed 48 workers who escaped three serious fires in western Pennsylvania. In each case the location of the fire was known but did not get communicated to many of those who had to evacuate. Sometimes, even the nature of the problem was not clearly communicated. Some workers began their evacuation knowing nothing about what was happening. In an effort to improve emergency communication National Institute for Occupational Safety and Health (NIOSH) researchers worked with safety professionals to determine what sorts of information are critical in a mine emergency. An extensive list was generated, which proved too long to be remembered by individuals. The list was therefore collapsed into six categories. A communication protocol was derived from these categories.

By Edward A. Barrett, Kathleen M. Kowalski-Trakofler

This paper discusses the application of a training intervention that uses degraded images for improving the hazard recognition skills of miners. Method: NIOSH researchers, in an extensive literature review, identified fundamental psychological principles on perception that may be employed to enhance the ability of miners to recognize and respond to hazards in their dangerous work environment. Three studies were conducted to evaluate the effectiveness of the degraded image training intervention. A model of hazard recognition was developed to guide the study. Results: In the first study, miners from Pennsylvania, West Virginia and Alabama, who were taught with the aid of degraded images, scored significantly better on follow—up hazard recognition performance measures than those trained using traditional instructional methodologies. The second and third studies investigated the effectiveness of the training intervention at two mining companies. Data collected over a3—year period showed that lost—time injuries at mines in Alabama and Illinois declined soon after the training intervention was instituted. Impact on Industry: Further exploration of the hazard recognition model and the development of other interventions based on the model could support the validity of the steps in the hazard recognition model.

Until man was able to produce light, his working day was pretty much limited to daylight hours. Underground miners have a special problem because in a mine it is just as dark during daytime as it is at night. The first devices used for mine lighting were torches and open flame 011 lamps. Torches made from twisted grass and dipped in tallow or pine pitch would burn for a while, but they made a lot of smoke and probably went out when they were needed most. During the 15001s, miners lamps consisted of a small metal dish with a hook attached to hang it up. The saucer-shaped dish was filled with animal or fish oil and a wick made of twisted fibers was laid In the 011 and hung over one edge where it would burn. This lamp would burn longer than a torch, but the amount of light cast by the pale, flickering flame was probably only a little better than no light at all.

Jan 1, 1976

By David C. Byrne

From an engineering perspective an ideal industrial noise control solution focuses directly on the actual source of the poise. Eliminating the noise-generating mechanism altogether obviates the need for other noise contra l treatments or hearing protection devices. However, in cases where attenuating the source is not feasible engineering controls must be oriented toward blocking the path that the sound waves travel toward employees. Acoustical enclosures are commonly used as sound path treatments to contain the noise from a machine: alternatively a control room/booth or equipment operator's cab may be used to isolate the worker from the noise. Anyone who has successfully used acoustical enclosures knows that the design procurement, and installation process is deceptively simple. Alt too often First-time efforts fait to account for many of the constraints that can render the enclosure essentially useless. Things that cannot be overlooked include: providing convenient worker access (physical and visual): allowing for proper machine operation/product flow; and supplying fresh air or preventing undue heat or contaminate build-up inside the enclosure. All of these factors must be given careful consideration, otherwise the enclosure will not perform adequately.

By G. T. Lineberry, W. J. Wiehagen

A Paradigm Shift As market economists, mine managers are interested in "staying in business" and even "prospering." Bottom-line results are the "order of the day." Concern for bottom-line results invokes questions such as: How much was produced? At what cost? And, was anyone injured? While these questions will always carry everyday emphasis at the mine, they are fundamentally lacking in that they often appear, especially to lower levels of management and to the production worker, as preeminent concerns. Driven by market economics, many organizations have decentralized, outsourced, downsized, restructured, and formed new coalitions. Investments in new technology and concentration on productivity have been part and parcel with these changes, contributing to improvements in both safety and efficiency. A reason for (and, perhaps a result of) these improvements has been the development of a highly experienced and flexible work force. These changes in mining present an interesting opportunity to modify a few paradigms about work life in general, and perhaps a few paradigms about how we invest in the miner, in particular. Studying these issues now might offer some interesting opportunities for the future, as the foundations for the next generation of mine workers are laid. With the average "experienced" U.S. miner five to fifteen years from retirement, perhaps a key determinant of future success in the world market might be how well we make the transition from today's work force to the work force of tomorrow. We can ill afford to wait a few more years to tap into the special knowledge residing within a veteran mining work force. The WCPM work Crew Performance Model, see pp. ) is one approach to defining, capturing, and transferring this expertise.

By J. C. Edwards, C. C. Hwang

In ventilated tunnel fires, smoke and hot combustion products may form a layer near the ceiling and flow in the direction opposite to the ventilation stream. The existence of this reverse stratified flow has an important bearing on fire fighting and evacuation of underground mine roadways, tunnels and building corridors. In the present study, conducted by the National Institute for Occupational Safety and Health, a CFD program (fire dynamics simulator) based on large eddy simulations (LES) is used to model floor-level fires in a ventilated tunnel. Specifically, the critical ventilation velocity that is just sufficient to prevent the formation of a reverse stratified layer is simulated for two tunnels of different size. The computer code is verified by checking the computed velocity profile against experimental measurements. The CFD results show the leveling-off of the critical ventilation velocity as the heat release rate surpasses a certain value. At this critical ventilation, the ceiling temperature above the fire reaches a maximum for both tunnels. The velocity leveling-off can be explained from this observation. An extended correlation of Newman (Combust. Flame 57 (1984) 33) is applied to the temperature profiles obtained by CFD. At the critical ventilation, temperature stratification exists downstream from the fire. The computed critical ventilation velocity shows fair agreement with available experimental data taken from both horizontal and inclined fire tunnels. The CFD simulations indicate that the Froude modeling is an approximation for tunnel fires. The Froude-scaling law does not apply to two geometrically similar fire tunnels. The CFD results are compared with two simple theories of critical ventilation by Kennedy et al. (ASHRAE Trans. Res. 102(2) (1996) 40) and Kunsch

By Julie Mitchell, Robert King, Len Eros

The Bureau of Mines has studied the Deserado Mine computerized monitoring and control system, located in Rangely, Colorado, to acquire knowledge about the overall costs and benefits of mine monitoring systems. The Deserado system is a complex system monitoring environmental parameters, electrical power, and operation of all mine equipment, and controlling the entire conveyor haul age system. This paper discusses the evaluation of the Deserado monitoring system from initial design through system installation and operation. It also examines the costs, benefits, and performance of the monitoring system.

By Eugene V. Cilento, R. Clark Lantz, Kevin A. DiGregorio

"A microscope-based spectrophotometer has been developed to measure superoxide release from single pulmonary alveolar macrophages (PAM) or other phagocytes in culture. Results indicate that PAM respond to stimulation by phorbol myristate acetate (PMA). It appears that some PAM do not release 02 upon stimulation by PMA; however, those that do release 0, show differences in: (I) the total amount of 0, released, (2) the rate of release of 02 and (3) the time delay for release of 02. The significance of measuring 02 release from single cells is two-fold. It allows the simultaneous study of 02 release and electrical potential changes across the membrane of PAM and it allows the study of differences in 02 release among cells. Thus, the function of Normal PAM and the dysfunction of PAM exposed to coal dusts can be more closely studied on single cells.Pulmonary alveolar macrophages (PAM), free cells found in the lungs, protect the lungs by removing inhaled foreign debris and bacteria. The macrophages do this by engulfing and then internalizing the foreign matter (phagocytosis). Stimulation of PAM causes the release of super-oxide radical (02) which has been shown to be the primary metabolite involved in the killing of bacteria by phagocytes (3,8,12). The super-oxide radical is highly reactive and is spontaneously or enzymatically converted to other antibacterial oxidants, including hydrogen peroxide (H202), singlette oxygen ( 02), hydroxyl radical toil'), and hypochlorous acid (HOCl) (2, 3,8,11,12).Exposure of PAM to dusts may lead to dysfunction of this cell-type and to a greater risk of lung damage or infection upon subsequent exposure to toxic dusts. To date, much of the research with this cell-type has used cytotoxicity (cell death) as a measure of dysfunction. Although this is an important end point, PAM dysfunction may occur at doses below those which lead to cell death. In addition, dysfunction has been measured using large numbers of cells. In order to obtain a clear understanding of the mechanisms involved in dysfunction, measurements should be made on single cells. As mentioned earlier, one of the major roles of this cell type is its anti-bacterial actions. Therefore, asessment of release of superoxide radical in single cells is important in determining the functional behavior of PAM before and after exposure to dusts. Since measurements of 02 production have not been made on single cells the purpose of this study is to develop the methodology needed to study release of 02 from single cells.Recent studies have suggested that a relationship exists between the release of 02 and changes in the electrical properties of phagocytes. The change in membrane potential is thought to be the initial step in superoxide production (6,9). Stimulants which cause 02 release also cause changes in the transmembrane potential of phagocytes (9) and in the permeability of the cell membrane to ions (6). For example, stimulants which cause the release of 0, from neutrophils have also been shown to increase the membrane transport of Na+ , K+ and Ca+2 and stimulation of macrophages leads to increases in Na and perhaps Ca permeability with a subsequent change in membrane potential. In some cases, phagocytic activity has been shown to depend upon the extracellular concentrations of these ions (6). Holian and Daniele (7) have shown evidence that the redistribution ofcellular Ca in alveolar macrophages is an initial step leading to 0, release. In order to provide direct evidence that 02- production is related to electrical changes across the plasma membrane of phagocytes, these two phenomena must be analyzed simultaneously on single cells. Ultimately, measurements of 0, release using the methodology developed in this study will be combined with electrophysiological tech¬niques to study both superoxide release and membrane potential changes simultaneiously on single PAM, and to examine the effects of coal and mineral dusts on their physiological fu"

Jan 1, 1988

This report discusses the nonfuel critical minerals position of the United States-both current and future (to the year 2000). We have assumed that there will be no major global disturbances-military, political, or economic-during the rest of this century. However, international relationships, strategies, and conditions that affect the supply of minerals are very tenuous, normal trading patterns can be easily upset, and national and ideological objectives can and do interfere with "normal" free market conditions. For example, the Department of Defense has reported that the Soviet Union is engaged in a strategy designed to reduce the availability of strategic minerals, through either physical disruption, market manipulation, or domination of producing or neighboring states. Although such a strategy poses serious concerns for the United States and the free world, the impacts of disruptions are not covered in this publication. Historical Perspective The modern industrial economy of the United States is founded on the production and use of minerals.* Two hundred years ago our forebears began taming a raw continent, developing a base for agriculture and a rudimentary minerals producing system. In the 19th century, with the aid of imported labor and capital, the development of America's vast natural resources was undertaken, and the transition from an agricultural to industrial society was underway. By the century's close, the United States had emerged as a great industrial power, partly through the development of such mineral resources as iron in Minnesota and coal in Pennsylvania.

Jan 1, 1983

By R. J. Seibel

A statistical comparison of the dust exposures of coal miners with identical occupations in Pittsburgh, Pocahontas, Freeport, and Kittanning seams was conducted. Results indicated that, in some cases, identical occupations have different dust exposures in different seams. For example, the continuous miner operator in the Pittsburgh and Pocahontas seams is exposed to more dust than the same man in the Kittanning seam, but the Kittanning seam has more dust along the haulage roads than the other seams. Also, average dust exposures for similar occupations in continuous and conventional mining operations are similar.

Jan 1, 1974

After a stagnant performance in 1982, gross national product (GNP), industrial production, and employment increased during 1983 in nearly all industrial nations, with the U.S. performance generally leading the uneven worldwide recovery. Real U.S. GNP increased 3.3 percent in 1983 (table I). Although investment in nonresidential structures declined, total nonresidential fixed investment in the United States was up 1.5 percent following a 1982 decrease. The increase in worldwide industrial activity and demand in 1983 put greater pressure on prices in many countries. Prices increased from less than 3 percent in the Federal Republic of Germany, Japan, the Nether-lands, and Switzerland to as much as 10 percent in nearly all the other Organization for Economic Cooperation and Development nations. The annual inflation rate in the United States was 4.3 percent (based on the GNP fixed-weight price index).

Jan 1, 1984

By Julius G. Chang

Against the receding background of the October stock market crash and the December overhang of inventories, the economy began with a shaky start in 1988. As 1988 began, the Administration's estimate of real growth for 1988 had just been reduced from 3.5% to 2.4% and economists and other ob-servers were concerned that the expansion that was 5 years old might be near the end and that a recession might be around the corner. The ensuing moderately strong economic activity, however, belied all the negative signals that were evident earlier, and the real GNP continued to grow at an estimated 2.3% annual rate during the first quarter of 1988, extending the ongoing recovery into the sixth year (table 1.). The relatively accommodative policy of the Federal Reserve Board (the discount rate was cut by 0.25% in January), a strong performance by the export sector, and the revival of consumer spending were major forces underlying the economic strength. But as the quarter drew to a close, signs of tight capacity utilizations were apparent in many of the export and capital goods sectors, including textile, chemical, plastic, metal, and machinery. Employment was at a record high level while the unemployment rate was close to a historical low. Prices were rising at a faster pace than those of 1987, and the dollar resumed its slide after a brief recovery in January and February. These factors gave rise to the fears of higher inflation. Long-term interest rates increased, casting a pall over the prospect of a robust growth for the rest of the year.

Jan 1, 1988