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Articles 170191 - 170220 of 198087

Full-Text Articles in Engineering

Deployment Of Self-Contained Self Rescuers In Australian Coal Mines, Najdat I. Aziz, Ernest Y. Baafi, Paul Mackenzie-Wood Jun 1999

Deployment Of Self-Contained Self Rescuers In Australian Coal Mines, Najdat I. Aziz, Ernest Y. Baafi, Paul Mackenzie-Wood

U.S. Mine Ventilation Symposium

In view of the recent mine disasters in the Australian coal mines, there has been a need to develop strategies to introduce SCSRs into coal mines to replace the approved filter self rescuers. A study was undertaken to evaluate the performances of the units in the normal Australian underground coal mine conditions. The study involved a laboratory and field trials at four underground coal mines using a total of 37 volunteers. These volunteers walked along the escape route at their respective mines on the first day carrying the SCSRs on their belts. The walk was repeated on a second day …

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Mine Safety In Chinese Coal Mines: Today And Tomorrow, Xintan Chang, Yunxiu Sai Jun 1999

Mine Safety In Chinese Coal Mines: Today And Tomorrow, Xintan Chang, Yunxiu Sai

U.S. Mine Ventilation Symposium

As a result of governmental agency restructuring, China's coal industry has been going through evolutionary changes as well in recent years. This paper discusses the various structural changes within the former Ministry of Coal Industry (MOCI) that occurred recently and its impact on coal production, health and safety regulation enforcement, safety training, and higher education.

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Equivalent Roughness And Its Application In Calculating Friction Drag Of Mine Roadway, Yan Zhou, Xingshen Wang Jun 1999

Equivalent Roughness And Its Application In Calculating Friction Drag Of Mine Roadway, Yan Zhou, Xingshen Wang

U.S. Mine Ventilation Symposium

Some roadways, which do not behave as "wholly rough pipe" as we expected, will have different impact on airflow in a mine ventilation network because of the low Reynolds numbers. For a "non-Wholly-rough" roadway, its resistance factor (R) or the friction factor (¦) is not only dependent upon the relative roughness but also dependent upon the Reynolds number, which varies directly as the flow rate. In this case, R or ¦ is no longer a constant independent of flow rate. Thus, in order to correctly calculate the friction drag of the same roadway for different flow rates, ¦ must be …

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Practical Values Of Friction Factors, Brian S. Prosser, Keith G. Wallace Jun 1999

Practical Values Of Friction Factors, Brian S. Prosser, Keith G. Wallace

U.S. Mine Ventilation Symposium

Over the past fifteen years, engineers from Mine Ventilation Services, Inc. (MVS) have measured numerous friction factors at many different types of mining operations. The results of these measurements indicate that standardized friction factors referenced in most ventilation textbooks are greater than those measured in the field for similar airway support systems. Many referenced friction factors are still based on G. E. McElroy's classic paper "Engineering Factors in the Ventilation of Metal Mines" published in 1935. Most mechanized mines now incorporate airways that are larger, have more advanced support systems, and more uniform openings. This paper describes the measurement techniques …

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Direct And Inverse Problem Of Diffusion With Simultaneous Linear Accumulation, Petko Ivanov Lalov Jun 1999

Direct And Inverse Problem Of Diffusion With Simultaneous Linear Accumulation, Petko Ivanov Lalov

U.S. Mine Ventilation Symposium

Mine working contamination occurs when diffusion in a constant velocity medium is accompanied by a process of absorption and accumulation of the diffunding medium, as described by the generalized convective diffusion equation proposed by J.L. Litwiniszyn. The first part of this article discusses the problem of finding a solution to the integro-differential equation under study for defined initial and boundary conditions corresponding to working with a finite length (direct problem). The second part solves the problem of determining the coefficients of this equation by using the results of measurements of the contaminant concentration by sensors positioned along the working (inverse …

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Modelling Of The Occurrence Of Hydrogen Sulphide In Coal Seams, A. D. Stewart Gillies, Mehmet S. Kizil, Hsin Wei Wu, Timothy J. M. Harvey Jun 1999

Modelling Of The Occurrence Of Hydrogen Sulphide In Coal Seams, A. D. Stewart Gillies, Mehmet S. Kizil, Hsin Wei Wu, Timothy J. M. Harvey

U.S. Mine Ventilation Symposium

Hydrogen Sulphide (H2S) has been encountered within a number of Bowen Basin collieries, Central Queensland, Australia. High concentration occurrence during mining of a longwall panel raises a number of potential problems, which demand greater understanding to allow efficient mining while maintaining safe and healthy environmental conditions. Longwall panels at Mine A and Mine B have recently mined through H2S zones. The high H2S zone mined through at Mine A was wide and covering the whole length of the face comparing to the narrow H2S zone which was cutting the panel at 45° …

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Management Of The Mining Industry/Research Organization Interface, Brad John, Jeneth M. Spiliopoulos, Judy Beazley, Timothy J. M. Harvey, A. D. Stewart Gillies Jun 1999

Management Of The Mining Industry/Research Organization Interface, Brad John, Jeneth M. Spiliopoulos, Judy Beazley, Timothy J. M. Harvey, A. D. Stewart Gillies

U.S. Mine Ventilation Symposium

The purpose of a consultancy undertaken to assess management processes in research projects to improve communication between research organisations and the mining industry through the development of an improved mode of operation and customer interface is discussed. The consultancy was conducted using the Nadler and Tushman Congruency Model of Organizational Behaviour to assess components of a projects inputs, transformation process and outputs for their degree of congruence or 'fit'. As an example the University of Queensland (UQ) managed ACARP Project 'Maximising Coal Production in the Presence of Hydrogen Sulphide (H2S) Seam Gas' was used for illustration. An action …

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An Investigation Of Longwall Gob Gas Behavior And Control Methods, Steven J. Schatzel, William P. Diamond, Fred Garcia, John C. Lascola, Frank E. Mccall, Paul W. Jeran, Thomas P. Mucho Jun 1999

An Investigation Of Longwall Gob Gas Behavior And Control Methods, Steven J. Schatzel, William P. Diamond, Fred Garcia, John C. Lascola, Frank E. Mccall, Paul W. Jeran, Thomas P. Mucho

U.S. Mine Ventilation Symposium

The National Institute for Occupational Safety and Health (NIOSH) has initiated the use of a tracer gas in field studies to characterize geologic and mining factors influencing the migration of longwall gob gas. Three studies have been conducted using sulfur hexafluoride (SF6) at a coal mine in the Northern Appalachian Basin operating in the Pittsburgh Coalbed. Eight underground tracer gas releases and one gob gas venthole release are summarized. The results indicate that the gas flow in the bleeder network and in the interior regions of longwall panel gobs do not strongly interact and that the negative pressure …

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Flammable Gas Emissions In South African Gold And Platinum Mines Review Of Incidents And Accidents, A. P. Cook, C. F. Meyer, K. Balt Jun 1999

Flammable Gas Emissions In South African Gold And Platinum Mines Review Of Incidents And Accidents, A. P. Cook, C. F. Meyer, K. Balt

U.S. Mine Ventilation Symposium

Flammable gas emissions are relatively common and widespread across the South African gold and platinum mines, but a general lack of awareness has lead to an increase in flammable gas related accidents and fatalities over the last ten years. The gas is usually a mixture of hydrocarbons C1 to C4 with hydrogen, each in varying quantities, with methane and hydrogen predominant. The three most common causes leading to gas accidents are changes to the ventilation, lack of testing for gas, and contraband, with gas ignitions caused by contraband and illegal tampering with caplamps. Development work accounts for 70 percent of …

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Gob Well Flaring: Design And Impact Analysis, Daniel J. Brunner, Karl Schultz Jun 1999

Gob Well Flaring: Design And Impact Analysis, Daniel J. Brunner, Karl Schultz

U.S. Mine Ventilation Symposium

Currently, over 30 U.S. Coal Mining operations employ a system of degasification to assist in reducing the emission of methane into their mine ventilation systems. All of these mines use vertical gob wells. This is an effective gob de gasification technique for U.S. longwall coal mining operations, particularly when prime movers apply suction to the wellheads (active gas extraction). In most cases mine operators discharge gas recovered from gob wells directly to the atmosphere. This practice poses safety and environmental concerns, and wastes a potential resource. In the U.S. there are no standards for equipping actively extracted or passive gob …

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Design Of Methane Drainage Systems To Reduce Mine Ventilation Requirements, Michael D. Zuber, Charles M. Boyer Ii, Denise L. Delozier Jun 1999

Design Of Methane Drainage Systems To Reduce Mine Ventilation Requirements, Michael D. Zuber, Charles M. Boyer Ii, Denise L. Delozier

U.S. Mine Ventilation Symposium

There are numerous proven methods to drain methane from coal seams in coal mines. These systems include vertical wells drilled ahead of mining, horizontal boreholes, gob wells, and others. However, these drainage systems are not typically applied properly to optimize gas recovery and minimize the cost of ventilation to the mine. This lack of optimization generally occurs due to the large up-front costs associated with the drainage systems and the lack of knowledge regarding the drainage technology. This results in the mine having a "reactive" response to methane drainage issues as opposed to a "pro-active" plan for handling methane drainage. …

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Methane Ignitions On Roof Bolters In Underground Coal Mines, John E. Urosek, William J. Francart Jun 1999

Methane Ignitions On Roof Bolters In Underground Coal Mines, John E. Urosek, William J. Francart

U.S. Mine Ventilation Symposium

Although not as frequent in nature as ignitions on continuous miner or longwall faces, ignitions of methane on roof bolters have caused serious injuries to underground coal miners. After reviewing the accident reports for all roof bolter ignitions from 1981 to 1998, a summary of the forty-one accidents has been developed. Of interest in the database is the ignition source, method of face ventilation, local velocity, methane liberation, size of the methane body ignited, and the duration of the flame. Three example ignitions are included.

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A Proposed New Method To Determine The Effectiveness Of In-Heading Methane Control, F. J. Van Zyl Jun 1999

A Proposed New Method To Determine The Effectiveness Of In-Heading Methane Control, F. J. Van Zyl

U.S. Mine Ventilation Symposium

Various methods have been derived to determine the effectiveness with which ventilation systems clears headings of methane in a bord-and-pillar sections. A problem with applying these methods in underground sections is that the either require the face-area air quantity to be measured, which is virtually impossible in South African collieries, or they were developed for test galleries, making it difficult to use in production sections. Taking this into consideration the methane safety index (MSI) method was developed. The method utilizes methane data recorded around an active continuous miner (CM) and an activity log of cm operations to quantitatively assess methane …

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Evaluation Of A Continuous Miner Half-Curtain Dust Control System In A South African Underground Coal Mine, Bharath K. Belle, J. J. L. Du Plessis Jun 1999

Evaluation Of A Continuous Miner Half-Curtain Dust Control System In A South African Underground Coal Mine, Bharath K. Belle, J. J. L. Du Plessis

U.S. Mine Ventilation Symposium

The issues of public health and safety in the mining industry have been dealt with around the world through the intervention of governments. In 1997 the South African Department of Minerals and Energy (DME) sent out a directive to reduce the dust concentration level to /m3 at the operator's position for the sampling period. The reasons for the difficulty with compliance are: long headings up to 35m, inherently high dust generation rates of coal, and the increased use of highly mechanized equipment. A project was formulated under SIMRAC auspices with the title of "Underground Mechanical Miner Environmental Control" to …

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Laboratory Evaluation Of Pressure Differential Based Respirable Dust Detector Tube, Jon C. Volkwein, April L. Schoeneman, Steven J. Page Jun 1999

Laboratory Evaluation Of Pressure Differential Based Respirable Dust Detector Tube, Jon C. Volkwein, April L. Schoeneman, Steven J. Page

U.S. Mine Ventilation Symposium

A new type of respirable dust sampler was developed and compared side by side to personal gravimetric samplers in the laboratory. The new sampler correlates filter back pressure with mass accumulation to provide mid-shift and end-of-shift determinations of cumulative exposure. The sampler uses a small low flow rate pump to draw dust through a small detector tube that contains a porous urethane foam respirable classification section and glass fiber filter that collects respirable dust. Six different coal dusts were aerosolized in a laboratory dust chamber and a total of 118 triplicate observations were obtained. For individual coal types, the correlation …

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The Effects Of A Diesel Particulate Filter And Fuel Borne Catalyst On Engine Emissions, Mahé Gangal, Thierry Leprince, John Muter, Brent Rubeli Jun 1999

The Effects Of A Diesel Particulate Filter And Fuel Borne Catalyst On Engine Emissions, Mahé Gangal, Thierry Leprince, John Muter, Brent Rubeli

U.S. Mine Ventilation Symposium

CANMET has been involved in an industry-government program to assess the quality of mine air and to improve the working environment. One aspect of the program is to reduce diesel particulate matter (DPM) generated by heavy-duty diesel vehicles having low exhaust temperature duty cycles. The low exhaust gas temperatures that are common in modem engines lead to insufficient regeneration of diesel particulate filters (DPF). A study was undertaken in partnership with DCL International to examine additive assisted regeneration. This study uses a cerium based fuel-borne catalyst to complete the regeneration of a DPF. Regeneration of a DPF occurs when the …

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An Integrated Approach To Control Diesel Particulate Matter In Underground Coal Mines, Pramod C. Thakur, Larry D. Patts Jun 1999

An Integrated Approach To Control Diesel Particulate Matter In Underground Coal Mines, Pramod C. Thakur, Larry D. Patts

U.S. Mine Ventilation Symposium

Diesel engines were introduced in European, Asian, and Australian coal mines nearly fifty years ago and more recently in U.S. coal mines. Their use minimizes the risks of mine fires and gas explosions associated with trolley wire haulage. While there is no epidemiological evidence that properly diluted diesel exhaust creates any health hazard, some concern persists about the long-term effects of inhaling diesel particulate matter. Existing control technology has been able to dilute all gaseous components of diesel exhaust to safe levels. Because there is no medically established threshold limit value for diesel particulate matter in U.S. coal mines, it …

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Mine Fire Detection In The Presence Of Diesel Emissions, J. C. Edwards, R. A. Franks, G. F. Friel, C. P. Lazzara, J. J. Opferman Jun 1999

Mine Fire Detection In The Presence Of Diesel Emissions, J. C. Edwards, R. A. Franks, G. F. Friel, C. P. Lazzara, J. J. Opferman

U.S. Mine Ventilation Symposium

A series of four coal combustion experiments was conducted at the National Institute for Occupational Safety and Health's (NIOSH) Pittsburgh Research Laboratory (PRL) in the Safety Research Coal Mine (SRCM) to evaluate the response of fire sensors to a small 0.61 m square smoldering coal fire which transitions to flaming combustion in the presence of diesel emissions. An optical path smoke sensor alarmed earlier than a point type diffusion mode ionization smoke sensor, which alarmed prior to a co alert value of 5 PPM above ambient. The presence of steady state diesel emissions resulted in a decrease in the optical …

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Computer Simulation Of Climatic Conditions For Underground Automated Mines For Standard And Reduced Airflow Requirements, Julian Partyka, Stephen Hardcastle, Charles Kocsis Jun 1999

Computer Simulation Of Climatic Conditions For Underground Automated Mines For Standard And Reduced Airflow Requirements, Julian Partyka, Stephen Hardcastle, Charles Kocsis

U.S. Mine Ventilation Symposium

This study demonstrates the importance of ventilation in an automated mine through climatic simulations. These have been performed on workings located at depths of 1000 m to 3000 m below surface in an underground metal mine. Each active working area employs either an electric or a diesel piece of equipment that has a full load power output of 100 kW to 200 kW. The airflows considered in the mining areas were standard full-flow conditions, i.e. 100% (6.5 m3/100 kW), and 125%, 75%, and 50% of full-flow. The analyses show, for instance, that a 100 kW electric machine can increase the …

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Non-Destructive Field Measurements Of Rock Temperature And Heat Flow In A Hot Mine, Vilen P. Chernyak, Eduard N. Malashenko, Pierre Mousset-Jones Jun 1999

Non-Destructive Field Measurements Of Rock Temperature And Heat Flow In A Hot Mine, Vilen P. Chernyak, Eduard N. Malashenko, Pierre Mousset-Jones

U.S. Mine Ventilation Symposium

A number of thermophysical measurements were carried out at the Meikle mine in Nevada in order to obtain new data concerning heat flows and wall temperatures in a hot mine. This was necessary to verify known methods of heat flow calculation and compare experimental with theoretical results. The Meikle mine was chosen because it is operated in an area of high rock temperature caused by the hydrothermal nature of the deposit and the presence of water at 60°C. The airflow rates in some of the inactive areas and the predicted background rock temperature at the mine are similar to those …

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Author's Index, Multiple Authors Jun 1999

Author's Index, Multiple Authors

U.S. Mine Ventilation Symposium

No abstract provided.

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Ventilation Network Optimization For Deep Mines, Ventzislav Bojilov, Mitko Hadjiev, Georgi Shoushoulov Jun 1999

Ventilation Network Optimization For Deep Mines, Ventzislav Bojilov, Mitko Hadjiev, Georgi Shoushoulov

U.S. Mine Ventilation Symposium

The development of underground mines in Bulgaria has reached depth limit. The conventional approach for engineering the mine ventilation is unsatisfactory under the existing level of concentration and intensification of mining work under the already complicated mining and geological conditions. This necessitates the optimization of ventilation networks for achieving the required efficiency and reliability. Direct measurements in mines has created an adequate numerical mine ventilation model. This model can optimize and forecast the future development of the mine ventilation system with the help of computer software. By means of the prepared nomograms the individual parameters of the ventilating flow are …

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Axial Fan Monitoring By Pressure Transients Close To The Blades, A Preliminary Study, Ian Loomis, Shaun Ramsay Jun 1999

Axial Fan Monitoring By Pressure Transients Close To The Blades, A Preliminary Study, Ian Loomis, Shaun Ramsay

U.S. Mine Ventilation Symposium

As the axial fan blades move within the fan case pressure transients are developed, which can be measured and qualified by a fixed point monitor. The nature of the pressure transient pattern observed close to the fan blade varies with the location on the fan performance curve. Measurement of the pressure fluctuation around the fan blade ring reveals the minute variation in pressure associated with the movement of the air within the fan. Such observations could be the basis for an on-line fan monitoring system based on the acoustic emissions from the fan blade. This paper describes a preliminary study …

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Simulation Of Airflow Expansion Requirements For An Exhaust Raise Common To Two Mines, Eurel De Souza, László Götz Jun 1999

Simulation Of Airflow Expansion Requirements For An Exhaust Raise Common To Two Mines, Eurel De Souza, László Götz

U.S. Mine Ventilation Symposium

A complex raise system managed by Battle Mountain Canada Ltd. serves as a main exhaust ventilation airway system for two mines, Golden Giant mine and David Bell mine. Increased exhaust airflow requirements associated with new orebody development at Golden Giant mine have necessitated a study to investigate the feasibility of expanding the exhaust raise system capacity while maintaining exhaust requirements at David Bell. This paper describes a complex ventilation study aimed at optimizing exhaust ventilation conditions for the raise system common to the two operating mines.

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Autocad Based Mine Ventilation Analysis, Ted Sartain, Don Scheck Jun 1999

Autocad Based Mine Ventilation Analysis, Ted Sartain, Don Scheck

U.S. Mine Ventilation Symposium

Mine Vent is a mine ventilation analysis system which runs inside AutoCAD and uses the Penn State and other ventilation simulators. Working from AutoCAD as-mined and projected mine maps, the user picks the node locations and connects them with branches that correspond to the airway paths. Where survey data is not available, the system uses formulas to compute resistances. The system prompts the user for necessary parameters but the branch lengths are automatically computed. Powerful editing features reduce the time to modify existing schematics and try alternative ventilation options. The system also includes a survey data reduction module which outputs …

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Ventilation System Design For A Thin-Seam Mining Panel, Darren Holman, Ian Loomis, Malcolm Mcpherson Jun 1999

Ventilation System Design For A Thin-Seam Mining Panel, Darren Holman, Ian Loomis, Malcolm Mcpherson

U.S. Mine Ventilation Symposium

The extraction of coal from thin-seams is an important component of the future of coal mining in the commonwealth of Virginia. For thin-seam mining systems to be successful they must be able to provide production comparable to the current production methods in thicker seams. This necessitates the extensive use of remote mining technology. Regardless of The level of automation of the remote systems, efficient ventilation remains of paramount importance. This paper investigates several thin-seam mine panel schemes and possible variations in the ventilation systems. The primary approach made, however, is one of a pair of parallel panels mined simultaneously. A …

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Performance Of Distributed Bagged Stone Dust Barrier In Combating Coal-Dust Explosions, Jan J. L. Du Plessis, Pierre S. Vassard Jun 1999

Performance Of Distributed Bagged Stone Dust Barrier In Combating Coal-Dust Explosions, Jan J. L. Du Plessis, Pierre S. Vassard

U.S. Mine Ventilation Symposium

The Kloppersbos Research Facility of the CSIR's Division of Mining Technology has developed a new method of building stone dust barriers. The new barrier makes use of a previous concept of containing stone dust in a bag, but incorporates a new method of rupturing the bag. This was achieved by adapting the closing mechanism and by balancing the stone dust content with the void in the bag. The bagged barrier was extensively tested in the 200-m test gallery. During these tests, it became evident that these bags could be made to rupture and spread stone dust when subjected to smaller …

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Modelling Of Gob Inertization With Nitrogen, Michael Michaylov, Elena Vlasseva Jun 1999

Modelling Of Gob Inertization With Nitrogen, Michael Michaylov, Elena Vlasseva

U.S. Mine Ventilation Symposium

The paper deals with a modelling of nitrogen distribution throughout gob so that the effect of inertization could be measured. The model takes into account flow transient character, methane liberation and different locations for nitrogen injection. Computer modelling, reflecting mathematical models is done by a specially created computer programme NITRO_ GOB, which allows dealing with different parameters of air leakage, of coal waste distribution as well as of gas picture in the gob before inertization. Effective evaluation of the most important parameters - injection place and nitrogen volume- on gob gas picture is illustrated under typical cross-section profiles of gas …

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Evaluation Of Discriminating Fire Sensors In Two Underground Coal Mines, William J. Francart Jun 1999

Evaluation Of Discriminating Fire Sensors In Two Underground Coal Mines, William J. Francart

U.S. Mine Ventilation Symposium

Fire detection in underground coal mines using carbon monoxide (CO) based monitoring systems has been very effective in many mines. Many systems have been able to detect fires in early stages of development at very low CO levels. However in mines which use extensive diesel haulage and support vehicles, the systems have been less sensitive to early detection due to diesel exhaust contaminants elevating baseline CO levels. A new technology has been tested in two underground coal mines which is designed to discriminate between the CO produced by diesel engines and CO from a fire by correcting the CO concentration …

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Gob Spontaneous Combustion In A Fully Mechanized Long-Wall Top-Coal Caving Face, Jingcai Xu, Jun Deng, Xinghai Zhang, Xingming Guo, Fu Wen Jun 1999

Gob Spontaneous Combustion In A Fully Mechanized Long-Wall Top-Coal Caving Face, Jingcai Xu, Jun Deng, Xinghai Zhang, Xingming Guo, Fu Wen

U.S. Mine Ventilation Symposium

Geological conditions allow, underground coal mines in China tend to use comprehensively mechanized roof-coal caving technique in an effort to gain a higher degree of mechanization at coal faces as well as higher coal production rates. As a face advances, a large amount of coal will be left behind in its gob area which may experience a self-enhancing process of coal oxidation and heat accumulation, ultimately leading to open fire. Such a self-enhancing coal spontaneous combustion process is a significantly impeding mine safety and productivity. A sound mathematical model is an important step to predict the probability of spontaneous combustion …

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