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By Donald W. Mitchell, John Nagy, Edwin M. Murphy

Information is presented on remote sealing of a mine passageway through a borehole by five methods : PPnneeuummaattiicc injection of mineral wool and sand, ureaformaldehyde foam , balloons , urethane foam, and caving by blasting . An adaptation of the method using pneumatically conveyed mineral wool was tried in an operating mine . Further research is needed to simplify and to improve the techniques involved , as well as to explore the possibilities of other methods and combinations .

Jan 1, 1964

By John N. Murphy

In fiscal 1996, the US Congress directed that the US Bureau of Mines (USBM) be closed. Certain functions were reassigned to other agencies. The remaining employees were separated and the unoccupied sites were decommissioned. As a result, 12 locations were closed and about 1,200 employees were terminated in March 1996. About 600 employees at five locations were reassigned to other federal agencies. This article provides a summary of the continuing functions, the agencies involved and the points of contact for each continuing function. The functions that were discontinued are also identified.

By K. L. Rubow

"Diesel exhaust and mineral dust concentrations have been measured for aerosols generated in the laboratory and as found in five underground coal mines- 3 utiliting diesel-powered hallage equipment and two electric-powered equipment. Two source apportionment techniques have been applied to differentiate between the mineral dust and diesel exhaust aerosol concentrations. The first technique, using a microbrifke uniform deposit impactor CMOUDI) for size selective sampling, is based on modeling aerosol size and the premise that the diesel exhaust portion of .the aerosol is predom1nately submicrometer and the mineral dust portion is mostly greater that one micrometer in size. The second technique, Chemical Mass Balance CCMB) modeling, was used to referee the analysis of diesel exhaust and mineral dust aerosol concentrations from the size selective sampling results. ,The MOUDI size distribution data were modeled to obtain parameters describing the fine and course fractions of the sampled aerosol and to estimate the contributions to each mode from both mineral ·dust and diesel exhaust aerosol sources. The results showed the size distribution of the mixed aerosols exhibited two definite modes with the minimum between the modes occurring at 0.8 um. For the diesel equipped mines, this analysts yielded an average value for the fraction of the fine aerosol attributable to mineral dust of 1 pct. Less than 5 pct of the coal mine diesel aerosol was found in the coarse size fraction. CMB analysis confirms the original premise for using aerosol size to separate diesel exhaust and mineral dust aerosol during sampling."

Jan 1, 1988

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

During 1999, there were six fatalities in surface mines involving haulage equipment colliding with a smaller vehicle or person, or backing over the edge of a dump point. All of these fatalities can be attributed to the extensive blind areas around large haulage equipment. Researchers at NIOSH are investigating various technologies that can be used to monitor these blind areas and provide information on nearby obstacles to an operator. So far, the technologies listed below have been tested on dump trucks used in surface mining. The selection of these systems was based on their ability to handle the tough environmental conditions found in mining operations and how well they detected obstacles out to 40 or 50 feet beyond the rear of large dump trucks. Some of the manufacturers of available collision warning and camera systems are also listed.

Jan 1, 2001

By Charles Vaught

This paper discusses the fact that US coal mining organisations are losing the knowledge they need in order to be able to respond to emergencies. The authors note that knowledge management provides a useful perspective from which to view the problem, but that the debate about what constitutes knowledge should be broadened to include a debate about what constitutes management. It is argued here that knowledge is actually shared knowing distributed across group members; that such knowledge can be managed by cultivating it; and that narrative is the medium through which this may be done. The paper then examines NIOSH research that has attempted to use such an alternative knowledge management approach to help potential mine emergency responders better deal with the predicaments they are likely to encounter on-site.

Jan 1, 2006

By Erica E. Hall, Robert H. Peters, Charles Vaught, Jon C. Volkwein

Coal workers’ pneumoconiosis is the leading cause of death due to occupational illness among U.S. coal miners. This disease is caused by miners’ exposure to excessive levels of respirable coal mine dust. A personal dust monitor (PDM) has recently been developed to provide near real-time feedback to miners regarding the level of respirable coal dust in the air they breathe. The main objective of this report is to document coal miners’ reactions to this device and how they make use of the information it provides. It summarizes a field study by the National Institute for Occupational Safety and Health that documented the opinions of 30 miners at 4 underground coal mines concerning the use of PDMs.

Jan 2, 2008

By Jeffrey Kohler, John J. Samrnarco, Thomas Novak, Lloyd Morley

Equipment control functions that were once hardwired are being implemented with software and very large scale integrated (VLSI) devices. Often this transition has resulted in increased flexibility, improved quality, and decreased costs. At the same time, it has created new concerns and challenges concerning worker safety. The visible and well-defined ladder diagram for relay-logic has been replaced by program in which the exact outcome for varied inputs can be more obscure. In the coal mining industry,-efforts to automate longwall mining systems hove resulted in semiautonomous machines operating within the same space as workers This paper describes an effort initiated by the National Institute for Occupational Safety and Health (NIOSH to identify the safety rules related to the use of processor-controlled equipment in mining. Specific findings in the areas of human factors, hardware, and some safety are presented in this paper, and a brief description of a plan to address identified weaknesses is given.

1. Data from the Mine Safety and Health Administration (MSHA) indicate that a total of 44,015 employees worked in underground mining locations in 2003, corresponding to 44,778 full-time equivalent (FTE) workers. • Ninety percent of underground employees (n = 39,735) were mine operator employees. • Contractors comprised 10% of all underground mining employees (n = 4,280) and comprised only 5.8% of all underground FTEs. • The majority of underground employees worked for coal operators (73.0%; n = 32,130).

Feb 1, 2005

By Arthur L. Murray

"Putting safety over , " using the accepted meaning of the word " Safety " as the elimination of personal injury , resolves itself into the prevention or disassociation of a combination of two distinct circumstances . Opportunity for accidents is afforded by conditions that are likely to cause injuries , but such injuries are effected only when the human body is placed in a position to be injured . As will be discussed later , in mining , as in most other industries , the degree of safety experienced depends upon the disassociation of these two circumstances , first , by making working conditions as free from hazards as possible , thus affording the minimum opportunity for accidents to occur , and secondly , the training of employees to recognize dangerous conditions and adopt measures to protect themselves and their fellow employees against injury . The responsibility for preventing accidents rests upon every person employed in an industry from the directing head down through the individual workers , and the safety of that industry will be proportionate to the extent that each member appreciates and accepts his individual responsibility . Hence , safety becomes decidedly a personal equation . Whether the personal equation will be so applied as to result in the greatest freedom from accidents , however , depends largely upon the initiative of those directing the industry . Putting safety over in a small mine presents the personal equation in a more intensified manner than the same endeavor in a large mine . Large mines , owing to their size and financial standing, can usually main ta in and support an effective safety organization with one or more directors who devote all their time to the supervision of safety work . Most small mines with a limited number of employees and limited capital can not afford and are not justified in supporting a paid safety organization , and must depend upon the close cooperation of their working force in maintaining safe working conditions . On the other hand , if proper supervision is exercised the small mine has in some respects advantages not afforded by the large mine . The limited workings in a small mine should afford less opportunities for dangerous conditions to arise and permits more frequent inspection of the entire mine . The small working force permits more latitude in the selection of employees known or believed to be either safe workers or amenable to safety educational work. Likewise , a small working force facilitates the carrying on of safety educational work and allows a closer personal contact between the superintendent and his employees .

Mar 1, 1923

By Jami M. Girard, Ed Mchugh

Slope stability accidents are one of the leading causes of fatalities at U.S. surface mining operations. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is currently conducting research to reduce the fatalities associated with slope failures. The purpose of this paper to discuss some of this research and to present potential new technologies for slope monitoring and design. The paper also briefly discusses various warning signs of slope instability, introduces the most common slope monitoring methods, describes the limitations of various slope monitoring systems, and presents some field results using some of this new technology.

By Albert E. Schreck

THIS CHAPTER concerns such minor nonmetals as greensand, meerschaum, mineral wool, staurolite, and wollastonite. GREENSAND Output of greensand (glauconite) was slightly higher than in 1958. Open pits of The Kaylorite Corp. (Calvert County, Md.), National Soil Conservation, Inc. (Burlington County, N.J.), and Inversand Co." (Gloucester County, N.J.) accounted for the entire production. Soil conditioning used about 72 percent of the greensand sold. The remainder was used as a water-softening agent. Prices for greensand, f.o.b. mine, ranged from $13 to $70 per short ton.

Jan 1, 1960

By S. Gallagher, A. Mayton, R. Merkel

The prolonged exposure of equipment operators to shock and whole-body vibration (WBV) IS linked to cumulative back, neck, and abdominal disorders. In low-coal mines, space restrictions make seat suspensions difficult to use in isolating operators from shock and WBV. Researchers at NIOSH, Pittsburgh Research Laboratory, are responding to these issues by investigating viscoelastic foams. For the full-load case. an ergonomic seat with viscoelastic foams isolated the shuttle car operator from shock at 15 Hz. Researchers used results from additional foam testing with an analytical model to identify viscoelastic foams that provide shock isolation at a frequency below 5 Hz.

By Christopher Mark

Since it was first introduced, the Coal Mine Roof Rating (CMRR) has been widely accepted as a tool for geologic characterization and mine planning. This paper discusses the application of the CMRR to another practical ground control problem. Extended cuts (cuts greater than 6 m (20 ft) in length) are commonly used with remote control continuous miners. Extended cuts can greatly increase productivity, but they have been associated with a number of fatal roof fall accidents. When extended cuts are attempted in weak roof, the roof may collapse before it can be bolted, causing hazardous conditions. Until now, it has not been possible to predict where conditions may not be suitable for extended cuts. In this study, data on the CMRR and extended cut experience were collected at 36 mines in 7 states. It was found that when the CMRR was greater than 55, deep cuts were routine in nearly every case. When the CMRR was less than 37, extended cuts were almost never taken. Between 38 and 55, extended cuts were feasible sometimes but not others. The data also shows that extended cuts are less likely to be stable if either the entry span or the depth of cover increases.

By Doris M. Hyde

Belize remained relatively insulated from the social and political turmoil that affected some of its Central American neighbors. This stability encouraged new foreign investments that assisted the economy, especially in tourism and agriculture. The mineral sector remained limited to construction-oriented materials. Oil exploration efforts continued by the various concessionaires.

Jan 1, 1987

By Gerrit V. R. Goodman, Charles D. Taylor, Edward D. Thimons, Jay F. Colinet

The importance of controlling respirable dust and methane gas levels in underground coal mining cannot be underestimated. While respirable dust can significantly affect the occupational health of underground coal miners, methane gas accumulations pose significant safety concerns for these same workers. Water sprays and machine mounted dust scrubbers offer effective control of respirable dust exposures and methane gas accumulations. Water must not only be applied carefully to avoid dust rollback to the machine operator but must create sufficient turbulence to remove dead zones that could contain high concentrations of methane gas. While the flooded-bed dust scrubber has been generally responsible for decreased worker exposures to respirable dusts, this device has proved effective in controlling methane levels at the face. This paper reviews practical applications of water sprays and dust scrubbers to control respirable dust and methane gas on continuous miner faces.

Jan 4, 2000

By R. V. Ramani, A. S. C. Owili-eger

The quantity of methane emitted into the mine atmosphere and the movement of gas through solid coal and the adjoining country rock are dependent on the physical properties of the medium, boundary con¬ditions, the initial gas pressure distribution, and the combination of natural and mining factors. Functional relationships between these factors are not yet known. Consequently, the development of rigorous mathematical models to predict methane flow into the mine air is difficult and to date no model has been reported which is capable of such a function. Thus far, empirical formulas available for the calculation of gas quantity released from underground sources require too much his¬torical data, not currently available. Again, these estimations are at best only crudely approximate. The numerical methods available have not been made practical enough for industry wide application. Therefore, the development of a relationship amenable to numerical analysis and practical enough for use in the industry would provide the flexibility lacking in analytical approaches. The mathematical models given in equations (7) and (8) are further attempts in presenting practical models for predicting the quantity of methane emission into the mine environment. Equation (7) is the steady state model and equation (8) is the unsteady state model.

Jan 1, 1974

By Oleg Terichow

Electrophoretic mobility measurements were made on samples of Florida phosphate slimes to determine the optimum conditions of coagulation and precipitation in aluminum sulfate solutions. The addition of silica sand and other selected materials as mutual coagulants has demonstrated the practicability of coagulating two dissimilar particle systems by elimination of the repulsive double layers. By proper selection of the solution and its concentration, the reduction of the double layer to a zero point of charge causes coagulation and rapid precipitation of both particle systems. Confirmation was found in filtration tests and sedimentation tests.

Jan 1, 1973

By Forrest T. Moyer

THIS CHAPTER of the Minerals Yearbook contains injury experience and related employment information for the coal-mining, coking, oil and gas, peat, and native asphalt industries in the United States for 1962. Injury experience is measured by the number of injuries sustained per million man-hours of exposure in each industry. No attempt has been made to combine these data and present rates reflecting the mineral-fuel industries because the hazards of the separate industries are not comparable. Tabulations showing the trend of injuries and employment for all mineral industries are presented in volume III of the Minerals Yearbook. COAL The injury-frequency rate for the coal-mining industry of the United States increased less than 2 percent, according to reports received by the Bureau of Mines. The number of fatal and nonfatal injuries per million man-hours in 1962 was 45.86, based on final data for anthracite mines and preliminary data for bituminous coal and lignite mines.

Jan 1, 1963

By Deno Pappas, Gregory Molinda, Eric Bauer, Christopher Mark, Daniel Babich

Groundfalls are much more likely to occur in coal mine intersections than in entries. NIOSH is using the experience of U.S. coal mines to determine the factors which influence intersection instability and provide guidelines for the safe excavation and support of intersections. Detailed field investigations have resulted in a database of U.S. coal mines containing 12 mines and 639 roof falls so far. By using the roof fall rate as the outcome variable, correlations between roof geology (CMRR), intersection span, and roof support have been established. Case studies have indicated that replacing 3- way intersections with 4-way intersections may not reduce the total number of roof falls. Additionally, the size of intersection spans tend to decrease with lower (weaker) CMRR. Protocols have been established for the collections of roof bolt parameters. The performance of individual roof bolts can now be tracked with roof fall rate.