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By D. O. Kennedy

THIS CHAPTER on minor nonmetals covers greensand, meerschaum, mineral wool, and wollastonite. Mineral wool was by far the most valuable material among these minor nonmetals reported in the United States in 1956. GREENSAND Output of greensand (glauconite) declined in 1956. The Kaylorite Corp., Dunkirk, Md., and the Inversand Co., Sewell, N. J., were the only firms that reported production of this commodity. Output came from open pits in Calvert County, Md., and Gloucester County, N.J.

Jan 1, 1958

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

APPENDIX C SCALING RELATIONSHIPS 1. Scaling Law for Fly Ash Crater Formation The scaling law derived for predicting crater diameters at different scales is developed below by considering the equation of motion of individual fly ash particles. It is assumed that the air drag on each particle is characterized by Stokes flow, and at the borehole - passage intersection the air velocity and the fly ash particle velocity are the same. The equations of motion for a fly ash particle are the following, (see Figure C-1).

Jan 1, 1973

1. In 2002, a total of 2,065 coal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Coal mines comprised 14.2% of all mining operations. • Bituminous mines comprised 92.5% (n = 1,910) and anthracite mines 7.5% (n = 155) of coal mining operations. • More than 70% of all coal mines were located in three states: Kentucky (28.7%), West Virginia (21.7%), and Pennsylvania (20.1%).

Jan 1, 2004

Background: The National Institute for Occupational Safety and Health (NIOSH) recently investigated ignition incidents resulting from drilling holes into sealed and filled plow frame sections. A farmer and farm worker were seriously burned in two separate incidents that occurred in the same county in New York under similar conditions. They had just penetrated sealed sections of their plow frames with electric drills when a roar of escaping gas at high pressure was heard, and the victims were thrown back by the gas jet and engulfed in flames. The flames were quickly extinguished ,but the victims suffered burns. NIOSH experts were asked to help find the cause of these hazardous incidents.

Jun 1, 1998

By W. C. Smith

The U.S. Bureau of Mines examined previous research on rib stability in an effort to develop a practical approach to understanding, characterizing, and controlling weak rib conditions in underground coal mines. Because success in stabilizing ribs depends on a basic knowledge of how weak ribs behave, the report reviews the mechanics of rib failure and the relationship of coal mine geology and pillar constraint to rib instability. Strategies for choosing an effective method of rib support are considered, and various rib support methods are discussed. Finally, the report documents techniques for monitoring ribs and use of models to assess rib stability; such monitoring and modeling can also help determine the most effective method for roof support.

Jan 1, 1992

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

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

Jan 1, 1973

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 Maria I. De Rosa

This report analyzes mine fires for all U.S. underground and surface coal mining categories by state and 2-year time periods during 1990-1999. Risk rate values are derived, and ignition source, methods of fire detection and suppression, and other variables are examined. The data were derived from Mine Safety and Health Administration (MSHA) mine fire accident publications and verbal communications with mine personnel. The analysis will provide the National Institute for Occupational Safety and Health, MSHA, and the mining industry with a better understanding of the causes and hazards associated with mine fires and will form a basis for future fire research programs.

Jan 1, 2004

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

1 9 THIS IS A DIGITAL COMPUTER SIMULATION OF THE VENTILATION SYSTEM OF A MINE LOCATED IN WASHINGTON COUNTY; PENNSYLVANIA. THE VENTILATION SURVEY ON WHICH THIS SIMULATION IS BASED WAS RUN FROM OCT. 27-30 AND ON NOV. 2;1976 IN THE ACTIVE PORTION OF THE MINE INBY COMBS SHAFT AND THE INACTIVE PORTION AROUND AND INBY DONAHOO SHAFT. FOLLOW-UP SURVEYS WERE THEN RUN ON FEB. 18 AND FROM MARCH 7-11;1977 TO INCLUDE THE MAIN HAULAGE SYSTEM OUTBY THE ACTIVE AREAS 0F THE MINE. ALL SURVEY DATA WAS NORMALIZED TO A STANDARD DENSITY OF 0.075 POUNDS/CU.FT. PRIOR TO THE CALCULATION OF INPUT PARAMETERS FOR THIS SIMULATION.

Jan 1, 1977

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

All output is saved in the file MFIRE OUT m the di¬rectory and on the disk containing the program The file can be inspected with a text processor and sent to a print¬er, if needed CONTENTS OF OUTPUT FILE The comment lines, reference temperature, air densi¬ty, a table of the units of measure for the results, and the average values are shown at the beginning of MFIRE OUT All input data will be shown in the output file if LOUT on Control line number 1 is _<-1 For each contamination source, a new branch will automatically be setup The new airway and junction ID numbers will not interfere with the original numbering scheme of the data file Next are the results of the selected simulation(s) in the following order network balancing, network balancing considering temperatures, transient-state modeling, and altered equilibrium due to fire and distribution of the contaminants. Depending upon the contents of the data file, and the simulation selected, attention, warning, and error message will be shown at locations where calculations resulted in unusual conditions

Jan 1, 1990

California&apos;s coal resources are estimated to be 100 million tons, of which 50 percent is lignite, 40 percent subbituminous, and 10 percent bituminous. The occurrence of coal in California is rather limited and is restricted generally to the foothill regions of the western slopes of the Sierra Nevada Mountains. Significant quantities of coal have been mined in five areas: Ione in Amador County, Alberhill in Riverside County, Stone Canyon in Monterey County, CorralHollow in Alarneda County, and Mount Diablo in Contra Costa County. Most of the coal was rnined in the early 1900s and was used locally for fuel. Current mining operations are located in Amador County near the city of Ione. The two producing mines supply fuel to a mine-mouth co-generation power plant. The fuel coal is processed prior to burning to extract montan wax. Because California does not have primacy, coal mining in the state is regulated by the Office of Surface Mining&apos;s Albuquerque, New Mexico, Field Office.

Jan 1, 1992

By Launa G. Mallett, Charles Vaught, Kathleen M. Kowalski, Charles D. Litton, Michael J. Brnich, Ronald S. Conti, Henry P. Cole, William J. Wiehagen

How do people behave when they are trying to get out of a fire? Are escape activities different in each incident, or will most actions be predictable across events? Do persons make the same sorts of decisions whether they are responding as individuals or as group members? Because the social costs of fire-related deaths and injuries are likely to continue to rise, societal pressure for greater safety will also undoubtedly increase. There are, therefore, compelling reasons to further our understanding of action in fires. If human behavior in fire is studied scientifically and predicted according to some well-defined principles, the benefits will be significant. Design engineers could incorporate real-world findings into their plans. Equipment manufacturers could gain from insights into how their technology is actually used in fire emergencies. Safety personnel would have a better appreciation of what constitutes adequate evacuation procedures. Trainers could upgrade the content of their courses that teach escape skills. The result would be an overall improvement in the quality of fire preparedness and safety.

Jan 1, 2000

By Andrew Cecala

During a recent National Institute for Occupational Safety and Health field evaluation of a newly designed filtration and pressurization system for an enclosed cab of a surface drill, it was determined that the drill operator&apos;s respirable-dust exposure was significantly increased during time periods when the cab door was opened to manually guide another section of drill steel into place to achieve additional cutting depth. Although no dust cloud was visible when the door was opened to perform this task, the drill operator&apos;s exposure was documented (over a three-day test period) to be nine times higher than when the cab door was closed. Even at this higher respirable-dust concentration, the drill operator&apos;s exposure remained well below the permissible exposure limit governed by the federal dust standard; however, an alternative method is being investigated to guide the drill steel in place in order to eliminate this increased exposure. .

Jan 1, 2008

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 A. T. Iannacchione

Underground stone mining represents an emerging sector for the U.S. mining industry. As this expansion takes mines under deeper cover and as more efficient mining methods are utilized, adequate stone pillar design methods will become more important. It is the purpose of this paper to examine current design practices and to discuss issues for safe mine layouts so that a rational first approach towards balancing the demands for increased production can be weighed against increased risk to worker safety from rib instabilities and pillar failures. Seventy-two stone mine pillar designs were examined. Pillars with width-to- height ratios below 1.5 and subjected to excessive stress levels appear more likely to fail. When width-to- height ratios fall below 1 .O, defects in the pillars, such as through-going discontinuities, can have a significant influence on stability. Discontinuity persistence, dip, material properties, and orientation are important factors controlling pillar strength. The influence of discontinuity dip, a characteristic easily identified in the field, was examined so that its presence could be accounted for in developing generalized guidelines for pillar design.

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

1 11 THIS IS A DIGITAL COMPUTER SIMULATION OF THE VENTILATION SYSTEM OF A MINE LOCATED IN WASHINGTON COUNTY, PENNSYLVANIA. THE VENTILATION SURVEY ON WHICH THIS SIMULATION IS BASED WAS RUN FROM OCT. 27-30 AND ON NOV. 2, 1976 IN THE ACTIVE PORTION OF THE MINE INBY COMBS SHAFT AND THE INACTIVE PORTION AFCUND AND INBY DONAHOO SHAFT. FOLLOW-UP SURVEYS WERE THEN RUN ON FEB. 18 AND FROM MARCH 7-11, 1977 TO INCLUDE THE MAIN HAULAGE SYSTEM OUTBY THE ACTIVE AREAS OF THE MINE. ALL SURVEY DATA WAS NORMALIZED TO A STANDARD DENSITY OF 0.075 POUNDS/CU.FT. PRIOR TO THE CALCULATION OF INPUT PARAMETERS FOR THIS SIMULATION. IN THIS RUN, THE ORIGINAL VENTILATION NETWORK HAS BEEN MODIFIED TO INCLUDE NEW INTAKE AND RETURN AIRSHAFTS AT THE WEST MAINS.

Jan 1, 1977

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 Thomas V. Falkie, R. Venkataramani

Proposing A Model In this investigation, a model of the form: n Y = a0 + E a x. A-1 v=l J J was postulated, where the number of independent variables "n" was originally fifteen. The following experimental hypothesis was to be tested: Null Hypothesis: the coefficients a = 0 J Alternate Hypothesis: One or more of the coefficients a 0 J Correlation and Regression To establish the alternate hypothesis and to test how well the proposed model fits the data, the conventional statistical techniques of correlation analysis and multiple linear regression analysis were used. Additionally, factor analysis was employed to investigate the dependency relationships in the data. Correlation and linear regression are well established statistical procedures in science and engineering. References on these procedures include Spiegel (1961), Anderson (1963), and Draper and Smith (1966). A simple example is stated here. If N observations are made of two variables, x and y, and it is desired to test this data to see if a linear relationship exists, then a model of the form: Y = a0 + a 1 x A-2 is proposed. The values of a0 and al may be calculated from the raw data by the "least square normal equations", which are:

Jan 1, 1972

A survey of roof and pillar conditions in underground limestone mines in the United States has revealed that bench mining of the floor between pillars can cause instability in the pillars at the perimeter of the benched area. Increased loading of these pillars was observed at several mines. Large inclined geological structures that are exposed in pillar ribs were observed to contribute to pillar instability. The paper describes a study that was carried out using numerical models to assess the effects of bench mining on pillar load and stability. It was found that the benched pillars shed load onto the surrounding pillars owing to their reduced stiffness. The pillars at the perimeter of the benching area will start shedding load as soon as benching increases the height of one side of the pillar. A case study is described which shows the effects of bench mining on limestone mine pillars.

Jan 1, 2007