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By Oliver Bowles

"Waste Granite in the Barre, Vermont, District: Waste in the great granite center at Barre, Vermont, consists of three types of material, the rough blocks rejected at the quarries on account of imperfections, the chips or spalls resulting from trimming and dressing at the cutting plants, and the granular and pulverized material from the dust collectors. The waste piles at the quarries of are immense proportions and constitute a serious handicap to quarrying in that they cover up good rock deposits, and are also so large that waste disposal becomes more and more expensive. The problem of utilization of such waste material is a topic of keen interest to all granite producers.Barre is not situated on a water route, and thus transportation costs prohibit the shipment of waste blocks for rip rap or ballast. Crushing plants use a small amount of this material for road construction, but aside from this, the waste is practically valueless.Investigators of waste utilization problems are awaiting with interest further information concerning an enterprise undertaken at Montpelier, Vermont, to utilize crushed granite for the production of brick similar to sand-lime brick. Granules of granite are mixed with lime, moulded, and hardened under steam Pressure, The brick produced are said to be of excellent quality for structural Purposes.There seems to be no logical reason why waste granite could not be utilized for the manufacture of building stone, and paving blocks, for many of the defects which condemn a stone for monumental purposes are not at all detrimental for building or street paving. F or the most part, monumental stone workers are not particularly interested in other branches of the granite in-dustry, and a combination of industries such as that suggested"

Jan 1, 1920

By John A. Johnson

"INTRODUCTION The use of wet drilling with adequate ventilation has largely controlled production of dust in drilling rock; however, in some operations, such as shaft sinking and modern tunnel driving, when each of a number of drills is operating in a small cross-sectional area, it is at times difficult to ventilate well enough to keep the dust concentration within desired limits.Some chemical compounds, known as wetting agents, when added to water in small quantities reduce the interfacial tension and make it possible for the solution to wet dust particles more effectively than water alone.This report presents results of tests on the effectiveness of two wetting solutions in reducing the amount of dust produced by wet drilling in basalt.ACKNOWLEDGMENTSThe tests were conducted at the Bureau's Mount Weather Testing Adit, Mount Weathe, Va. The author acknowledges the assistance and cooperation of Wing G. Agnew, superintendent; Marvin M. Reveille, mining-ngineering aide; and the rest of the crew at Mount Weather in conducting the tests. C. W. Owings, mining engineer, Safety Division, assisted in conducting some of the first tests and gave valuable advice and guidance throughout the work and in preparing this report."

Jan 1, 1943

Lower the respirable dust exposure of longwall shearer operators by use of a modified head to tail cutting sequence. Approach Modify the cutting sequence of double-drum shearer operations cutting unidirectionally head to tail, so that the tailgate drum is used to mine the entire coal face except when cutting out at the head. This approach would place the primary dust generating source, the cutting action of the drum, on the return air side of both shearer operators. How It Works Currently, 75% of the double-drum shearers in operation employ a unidirectional cutting sequence. On half of these operations, the primary cut is taken as the shearer travels from the headgate to tailgate ends of the face, with roof support to be advanced on the intake air side of the shearer. Typically, the leading (tailgate) drum is taking a full cut during the head to tail pass and the trailing (headgate) drum is cutting bottom coal. In this mode of operation, the dust generated by the trailing (headgate) drum can spread out into the walkway, and increase the respirable dust exposure of both head and taildrum operators. As an alternative, if the trailing drum is "free wheeling" or cutting minimal coal during the head to tail cut, and bottom coal taken by the tailgate drum during the tail to head clean-up pass, both operators are able to work on the intake air side of the primary dust generating source (drum) except when cutting out at the head. This modified cutting sequence would save wear on the conveyor and help to eliminate overloads, as well as reduce the respirable dust exposure of both shearer operators. This modifcation is only applicable to long-wail operations currently cutting unidirectional head to tail, and to those operations where this unidirectional cut would not produce operating constraints.

Jan 1, 1981

By R. V. Ramani, C. B. Manula, A. Owili-Eger

Recently, a collection of programs that will simulate a ventila¬tion system with extensive analyses and report-generating capabilities and error diagnostics has been developed (Didyk, 1974). It has pro¬visions to handle air injections, methane or gas emissions, and leakage. Additionally, it will solve problems where fixed and/or maximum air quantities are specified for some airways. Finally, the simulator has been structured to be extremely modular so that additions and revisions to the model can be easily made. The general aspects of the information flow and logical structure of the mine ventilation simulator are shown in Figure 14. The output from the methane emission model is input into the ventilation simulator for calculation of the concentrations in all branches of the network. The methane model and the ventilation simulator provide powerful tools for the analysis and planning of mine ventilation systems. INPUT DATA REQUIREMENTS In all of the mathematical models, several coefficients that de¬fine the characteristics of the ventilation system are used. For the ventilation simulator, these include the frictional characteristics of the ventilation regulatory devices. Considerable work has been done on the experimental determination of these coefficients for smooth pipes and well-defined mediums, but only limited data are available for actual mining conditions. FRICTION FACTORS: The frictional characteristics of mine airways affect both the dispersion of pollutants and air flow through the roadways,. They

Jan 1, 1975

By Thomas J. Fisher, Thomas Novak

Strong circumstantial evidence suggests that lightning has initiated methane explosions in abandoned and sealed areas of underground coal mines. The Mine Safety and Health Administration (MSHA) investigated several of these occurrences within recent years. The investigated explosions occurred at significant depths, ranging from 500 ft to 1200 ft. Data from the National Lightning Detection Network indicate a definite correlation between the times and locations of the explosions with those of specific lightning strikes. This paper addresses the question, "Can lightning cause potential differences capable of igniting methane-and-air mixtures at overburden depths at which underground coal mining occurs?" A mine depth of 600 ft was selected for this initial study. Computer simulations were performed, with and without the presence of a metal- cased borehole extending from the surface to the mine level. CDEGSTU software from Safe Engineering Services & Technologies, Ltd (SES) was used for the simulation.

By Charles D. Litton

Experiments were conducted to determine the optical scattering properties of diesel particulate matter (DPM) and various combustion aerosols from both flaming and smoldering combustion sources at discrete angles of 151 and 301 in the forward direction and at a light source wave length of 635 nm using a simple light scattering module. In addition to the scattering data, simultaneous measurements were made of the total aerosol mass concentration; light extinction at an average wave length of 546nm; and the response of a common bipolar ion chamber typical of residential smoke detectors modified to allow the aerosols to flow through the chamber. The results of these experiments indicate, for DPM and combustion aerosols, the intensities per unit mass concentration depend not only upon whether the aerosolis DPM or combustion aerosol but also upon the type of combustion aerosol. The results also indicate that the ion chamber responses are greatest for DPM, followed by the response to flaming combustion aerosols (FCA)and lowest for smoldering combustion aerosols (SCA). For light scattering, the greatest intensities are found for SCA, followed by the intensities from FCA, and lowest for DPM. This report describes the experiments, their results, and the use of these results to developed sign criteria for early warning fire sensor capable of the rapid and reliable detection of fires in atmospheres that may or may not be contaminated by the products produced from diesel engines. © 2002 Elsevier Science Ltd. All rights reserved.

The notion of wayfinding, as conceptualized by planners, geographers, and psychologists, denotes the ability of an individual to move from one point to another through physical space. In order to achieve this movement, a person relies on a cognitive map of spatial representations [Passini 1984]. Which features of this cognitive mapping will be stressed depend, in part, on the researcher's perspective. A planner, for instance, would tend to emphasize the effect of physical structures on mobility. A psychologist, on the other hand, might focus on individual differences in how human minds encompass and represent physical space [Evans et al. 1984]. There is yet another dimension to wayfinding that needs consideration, and it rests upon the idea that reality, as experienced by human beings, is mediated: "[People] have preselected and preinterpreted this world by a series of commonsense constructs ... which help them find their bearings in their natural and socio-cultural environment and to come to terms with it" [Schutz 1967]. These "common sense constructs" are arrived at socially and constitute the agreed-upon schemas that guide people's everyday activities. According to this principle, cognition is governed by some nonlogical factors that reflect not only individual procedures but collective ones as well. These group strategies, which are shaped by shared rules and values, influence "the information gathered, the ways it is processed, the inferences that are drawn, the options that are being considered, and those that are finally chosen" [Etzioni 1992]. From this perspective, cognitive maps, rather than being individual-centered templates of environmental images [Rovine and Weisman 1989] or representations of spatial relationships [Evans 1980], are partially group-centered schematic processes. As such, they are subject to reinterpretation, revision, and outside intervention [Kaplan and Kaplan 1982]. As intermediaries between the environment and behavior, cognitive maps serve as bases for decision-making. Traditionally, it has been assumed that good maps facilitate correct decisions, which in turn leads to optimal performance during wayfinding [Hunt 1984]. Given the argument that there is a social (non¬cognitive) facet to cognitive mapping, however, this image of a cognitive map as some sort of static reference construct that motivates individual action is too narrow and mechanistic. If cognition involves less a knowledge of the environ¬ment than it does the process of "giving it meaning through imposing an order on it" [Rapoport 1976], then wayfinding behavior is not j ust a function of setting and individual differences, but is also a function of one's "normative-affective" structure [Etzioni 1992]. Rapoport [1976] used such an assumption as the base for a set of hypotheses about the connection between "external demands" and "organismic factors." One significant assertion deriving from Rapoport's ideas is that environmental

Jan 1, 2000

Rock mass classification is widely used throughout the underground mining industry—in both coal and hard-rock mines. The technique has been successful because it— • Uses simple measurements to rate rock mass strength. • Helps mine planners to make the best use of geologic information in mine design. • Makes it possible to compare ground control experiences between mines, even when the geologic conditions are very different.

Jul 1, 2007

By W. H. Pailes, V. Castranova, D. Lewis, G. Goodman

We performed bronchoscopy with bronchoalveolar lavage (BAL) in 8 control subjects with no exposure to occupational dusts, 8 healthy power plant workers exposed to mixed dusts (primarily fly ash), 1 healthy coal miner and 1 rock driller with acute silicosis. All subjects were non-smoking males. We analyzed lavage effluents for total numbers of alveolar macrophages, lymphocytes and neutrophils and monitored chemiluminescence at rest (REST CL) and after stimulation with 3x10- M phorbol-12-myristate-13-acetate (PMA CL) or 2 mg/ml zymosan (ZYM CL). The data are as follows:

Jan 1, 1988

By T. R. Waters, F. Li, R. L. Huston

This paper describes the development of a multi-body biomechanical model that can be used to assess the risk of low back disorders due to occupational exposure to jarring and jolting from operation of heavy mobile equipment (e.g., trucks, haulers, graders, tractors, etc.) The four-element dynamic spinal model is capable of providing estimates of the force and acceleration responses of the head/neck, upper, lower, and middle torso resulting from vibration input collected in field studies. The paper also presents a method for using the model output to assess an individual's risk of low back disorder due to a specific jarring and jolting exposure.

By R. V. Ramani, V. T. Burgos, J. A. McClay

Summary Cost models have, long been confined to the accumulation and analysis of static-data.. While historical and time study data are valuable for control of existing operations, for new systems and equipment, and for projections, they need to be adjusted or modified. The availability of computer-oriented systems simulators provide yet another method for costing these systems and equipment. This investigation has introduced a concept whereby continuous, variable data can be assimilated and analyzed through the combination of an economic analysis model, which includes a direct costing capability, with a systems simulator. This tandem operation permits increased flexibility and greater atten¬tion to detail in the evaluation of mining systems. The direct costing process is carried throughout the majority of the model operations. Labor and capital costs may be computed directly, even in the absence of the systems simulator, while operating costs re¬quire input parameters, at present, from the subsystems of the Master Design Simulator. Since the costs computed are based on the perfor¬mance of each individual machine unit, the model may be used to evaluate equipment compatibility, system interaction at the mining face, and the effect of system elements on total mining costs. Additional applications of the cost model include the following: 1. Complete mining systems may be evaluated, over their economic life, to determine the feasibility of a profitable operation. 2. Costs associated with mining various segments of the coal deposit may be computed as a guide to planning the mine layout and scheduling the sequence of operations or acquisition of new

Jan 1, 1975

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 F. N. Kissell, H. K. Sacks

This study examines the accuracy of area sampling for measuring the dust exposure of mining machine operators in coal mines. The specific objective of this research was to find locations where an area sampler might work better than earlier studies have indicated. The results show that fixed-location area sampling cannot accurately predict the dust exposure of a machine operator, even when the best fixed location is sought, the fixed location is quite close to the operator and the bias due to the dust concentration gradient is corrected. Industrial hygienists have known for many years that area sampling is unsuitable for measuring air contaminant exposures in the workplace. Near contaminant sources, the dilution air and the contaminants are not evenly mixed. Therefore, when workers are near contaminant sources, exposure measurements must be taken from the worker's breathing zone to be accurate

Develop a method for mapping planar geologic features in deep underground mines where the presence of metal interferes with compass readings. Background A fundamental problem of mapping planar geologic features in deep underground mines is the presence of metal (water and air pipes, track, equipment, etc.), which affects the accuracy and consistency of compasses. Present geologic mapping methods include use of transits or theodolites, both of which are cumbersome and time consuming to use. To complicate the mapping, process each planar feature must be surveyed, and if that feature is not apparent on the opposite wall, it cannot be mapped. Another method of mapping is to stretch a tape measure between two survey spads and place a string along a planar feature on one wall and out into the opening until it intersects the tape measure. This method, in addition to being time consuming, is also inaccurate. Because detailed mapping of planar geologic features deep underground involves many repetitive measurements, a quick, accurate, and reliable method for making such measurements was necessary. The geolaser was developed to make such measurements in deep underground mines where metal interferes with conventionally used compasses.

Jan 1, 1990

By C. P. Lazzara, R. A. Franks, G. F. Friel, J. C. Edwards, J. J. Opferman

It was determined that a selection of different types of fire sensors could be used to discriminate mine fires from nuisance emissions produced by diesel equipment. A neural network (NN) was developed for application to coal, wood, and conveyor belt fires in the presence of diesel emissions and evaluated with the successful prediction of twenty-two out of twenty-three mine fires based upon a fire probability determination. The optimum sensor selection for the NN was comprised of a carbon monoxide (CO) sensor, two different types of metal oxide semiconductor (MOS) sensors, and an optical path smoke sensor.

By J. R. Wait, D. A. Hill

The feasibility of locating a buried vertical magnetic dipole source (horizontal loop) from surface measurements of the vertical and horizontal magnetic field components has been investigated by Wait (1971). , For sufficiently low frequencies, the magnetic fields have a simple static-like behavior, and a single observation of the ratio and relative phases of the vertical and horizontal field components is sufficient for location when the earth is homogeneous. However, when inhomogenieties are present, the surface fields will be modified, and source location may be more difficult. In order to obtain a quantitative idea of the surface field modifications, we consider a spherical conducting zone as a perturbation to the homo- geneous half-space. A rigorous solution for the buried sphere problem has been formulated by D'Yakanov (1959). Unfortunately, his solution is restricted to azimuthally symmetric excitation, and even then the solution is not in a convenient computational form. However, if the sphere is electrically small and is located at a sufficient distance from both the dipole source and the interface, the scattered fields can be identified as the secondary fields of induced dipole moments. The latter are equal to the product of the incident fields and the polarizabilities of the sphere. The details of the approach are given by Hill and Wait (1973). Wait (1968) has used this induced dipole moment approach for scattering by a small sphere above a conducting half-space. The method has the advantage that it is easily generalized to scatterers of other shapes for which both the electric and magnetic polarizabilities are known, such as spheroids (Van de Hulst, 1957). This concept has

Jan 1, 1973

By Michael A. Evanto, George J. Karabin

The Mine Safety and Health Administration, Pittsburgh Safety and Health Technology Center, Roof Control Division, is routinely involved in the evaluation of ground conditions in underground coal mines. Assessing the stability of mined areas and the compatibility of mining plans with existing conditions is essential to ensuring a safe working environment for mine workers at a given site. Since 1985, the Roof Control Division has successfully used the boundary-element method of numerical modeling to aid in the resolution of complex ground control problems. This paper presents an overview of the modeling methodology and details of techniques currently used to generate coal seam, rock mass, and gob backfill input data. A summary of coal and rock properties used in numerous successful evaluations throughout the United States is included, and a set of deterioration indices that can aid in the quantification of in-mine ground conditions and verification of model accuracy is introduced. Finally, a case study is detailed that typifies the complexity of mining situations analyzed and illustrates various techniques that can be used to evaluate prospective design alternatives.

Jan 5, 1999

By P. Kovalchik, S. Peng, G. Cole, R. Matetic

Previous studies conducted by the National Institute for Occupational Safety and Health (NIOSH) have shown that approximately 90 percent of coal miners and 49 percent of metal/nonmetal miners had a hearing impairment by age 50 (Franks, 1997). Mine workers are exposed to additional noise levels underground due to the reflection of machine-generated noise that would otherwise dissipate in an aboveground setting. Determining the sound-absorption coefficients is essential in modeling the sound field in an underground mining environment. Sound absorption is a measure of the amount of acoustic energy that strikes a surface and is absorbed rather than being reflected. The acoustic environment that mining machines operate in is a critical factor affecting the sound pressure level exposure for mining machine operators. Impedance tube testing is an inappropriate method for determining underground absorption coefficients due to the brittle composition of materials such as coal and slate. Classic absorption coefficient estimation using T60 measurements will not work well in an underground environment because the theory assumes a finite room, a diffuse field and a relatively uniform absorption. None of these assumptions are true in an open-ended mine entry. This paper presents a method using a ray-tracing technique to determine absorption coefficients for underground mines. Absorption coefficients are determined and presented for octave bands from 63 Hz to 8 kHz. The absorption coefficients are essential for determining and predicting potential overexposure to machine operators in different mine environments.1

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

The usual run time errors occur when illegal mathematical operations are attempted by MFIRE For exam¬ple, if the user enters a negative value for the input variable HEAT to model a heat sink or cooling station, a run tame error will occur because an exponential function is employed to better model the changing temperature dis¬tribution in the airways. DATA FILE ERRORS Two types of data file errors can occur. 1 An error may occur because the input data file itself is invalid This may be caused by: The data file cannot be found due to incorrect spelling, drive, or path specification Check the spelling and path at the prompt for location of the data file. The data file contains non-ASCII symbols Check op¬eration of the text processor to insure that only ASCII characters are produced Delete all non-ASCII and/or all out of place characters. 2 Data are accepted by the program, but are incorrect for the data types or ranges or the combination causes a data inconsistency This may be due to. An invalid character is located where a numerical value is required The input data value is outside the reasonable range The input data is insufficient to build the model for simulation. The input data exceeds the capacity of the program. PROGRAM ERROR DETECTION When the program is running, tracing messages are given on the screen indicating the group and lines of data that have been read and the section of the program that is executing Program termination indicates that problems are caused by the subsequent (not read) data file section. For each detected error, descriptive message starting with * ERROR * is issued and the program terminates. When a possibly wrong value and/or its calculated intermediate result is detected, a descriptive message starting with * WARNING * is issued and the program continues. If a modification of input value or calculated intermediate result is automatically made by the program, descrip¬tive message starting with * ATTENTION * is issued and the program continues. LOCATING ERRORS If a message indicates that the error condition occurred due to the data input file, locate and correct the data item. If no error message is issued, but the simulation results are not as expected, carefully check the list of input data shown in the output file WARNING messages and ATTENTION messages may reveal an error in the input data even though the program continues to operate Insure that the default values or modifications adopted by the program run are acceptable. Anomalistic data, though not incorrect or impossible, may lead to an unusual simulation For example, making a fan unusually powerful may prevent a normal strength fire from affecting the airflow distribution in the system Much care must be employed before considering an ex¬treme case. If a message indicates that the accuracy criterion in the temperature section of the program was not satisfied, a table detailing the current parameters of airways which have large fluctuation in the average air temperature from iteration to iteration is produced If the pattern of the parameters is clearly cyclical, while the variation of natural ventilation pressure is stable or cyclical from iteration to iteration, then, most likely there is no single equilibrium stage for the event If the variation of natural ventilation pressure decreases steadily though slowly, increasing the value of data item variables MADJ or ITN (on control line number 1) may allow convergence.

Jan 1, 1990

By Kathleen M. Kowalski-Trakofler

This paper discusses human judgment and decision making under stress. The authors review selected recent literature across various disciplines and suggest a definition of stress within the context of decision making during the management of emergencies. They also discuss fieldwork by the Pittsburgh Research Laboratory, NIOSH, which explores traumatic incident stress, the relationship between previous training and performance under stressful conditions, and human behaviour in underground mine fires. The authors assert that stress is one of the factors that decision makers must contend with in most life-or-death situations. They suggest that a better understanding of individual judgment and decision making activities whilst under stress would yield a better understanding of how people reach the choices they make in emergencies. This enhanced understanding would be of enormous value to emergency managers, researchers and policymakers.

Jan 1, 2003