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1999

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Articles 31 - 60 of 106

Full-Text Articles in Mining Engineering

Installation Of Two Main Fans At P.T. Freeport Indonesia's Underground Facilities, Felipe Calizaya, A. Mulyadi Jun 1999

Installation Of Two Main Fans At P.T. Freeport Indonesia's Underground Facilities, Felipe Calizaya, A. Mulyadi

U.S. Mine Ventilation Symposium

This study summarizes the technical aspects related to the installation of two main fans at P.T. Freeport Indonesia: one centrifugal and one axial. The fans were installed to increase the exhaust capacity of two vent systems. The 450 kW fan has been installed on surface to support an underground mine expansion project. The installation included the construction of a transition chamber, a retention wall, and the fan installation and commissioning. The 250 kW fan has been installed in an incline to increase the exhaust capacity of an ore pass ventilation system. The study presents the installation details from ground excavation …

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Theoretical Analysis Of Jet Fan Performance Using Momentum And Energy Considerations, Kuda R. Mutama, Allan E. Hall Jun 1999

Theoretical Analysis Of Jet Fan Performance Using Momentum And Energy Considerations, Kuda R. Mutama, Allan E. Hall

U.S. Mine Ventilation Symposium

Jet fans or ductless fans have been analyzed using momentum and energy considerations. This analysis is necessary for the mechanisms of mixing between the jet primary flow and the secondary or induced stream to be understood. In each case it is possible to predict performance in terms of pressure, flow ratios and hence the percentage mechanical efficiency of the whole system using equations derived from momentum and energy principles. The analysis given is suitable for situations where jet fans are utilized as area boosters in a mine ventilation system and in longitudinal vehicular tunnel ventilation. The energy and momentum equations …

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The Application Of Variable Frequency Drives To Mine Fans, Robert Z. Smith Jun 1999

The Application Of Variable Frequency Drives To Mine Fans, Robert Z. Smith

U.S. Mine Ventilation Symposium

During the past several years variable speed drives have become much less expensive for higher horsepower applications. This has created an opportunity to utilize this type of system in variable load mine ventilation applications where the traditional solutions were to use "in-flight" controllable pitch fans, variable inlet vanes or constant load systems and ignore the opportunity for power savings. This paper explores the basic characteristics of each type system and some of the advantages that each system offers for specific mine ventilation applications. The relative capital cost and operating cost of each type systems are also presented.

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A Navigating System For Ventilation Network Spatio-Temporal Control, Yuusaku Tominaga Jun 1999

A Navigating System For Ventilation Network Spatio-Temporal Control, Yuusaku Tominaga

U.S. Mine Ventilation Symposium

This paper presents a navigation system for spatio-temporal control of mine ventilation network to help keep miners safe in mine emergency situations such as mine fire, spontaneous combustion, and gas emission. The system is composed of sensors, computer simulation and binary controllers. The ventilation sensors are placed in specific branches of the ventilation network to monitor ventilation parameters such as air velocity. The Horonai coal mine, Hokkaido, Japan is used as an example to illustrate the applicability of the navigation system as on and in providing a safe evacuation route and to estimate the time interval to achieve steady airflow …

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High Speed Monitoring And Control System Uses Windows-Nt, Albert E. Ketler Jun 1999

High Speed Monitoring And Control System Uses Windows-Nt, Albert E. Ketler

U.S. Mine Ventilation Symposium

Millennia-DX™ is an advanced monitoring and control system especially designed for underground mining. An inexpensive 233+ Pentium computer running Windows-95 or -NT provides vast processing power that was unheard of just a decade ago. Engineered in-house from the ground up, Rel-Tek's new 32-bit Millennia-Dx™ software code now permits 10-mile data acquisition at an accelerated 115.2 KHz. New techniques and hardware have resulted in a totally integrated hardware/software package with uncompromising performance, features and reliability. A large coal mine installation is highlighted which installed a Millennia-DX system for monitoring carbon monoxide, but soon discovered the "data mining" capabilities which they enlisted …

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Optimization Of Main Exhaust Fan Systems At Battle Mountain Canada Ltd., Golden Giant Mine, László Götz, Euler De Souza Jun 1999

Optimization Of Main Exhaust Fan Systems At Battle Mountain Canada Ltd., Golden Giant Mine, László Götz, Euler De Souza

U.S. Mine Ventilation Symposium

In 1997, production needs required that the exhaust conditions at the Golden Giant Mine be maximized. One of the principal exhaust raises, the West Return Air Raise #1, designed to handle some 189 m3/s (400,000 cfm) but operating at 102 m3/s (216,000 cfm), was a primary candidate for optimization. This paper describes the major design changes and installation modifications carried out at this surface fan installation. The new installation not only outperformed the design expectations but also achieved the new mine exhaust requirements.

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Increasing Energy Efficiency Of Mine Ventilation Systems, Riyaz Papar, Andrew Szady, William D. Huffer, Vern Martin, Aimee Mckane Jun 1999

Increasing Energy Efficiency Of Mine Ventilation Systems, Riyaz Papar, Andrew Szady, William D. Huffer, Vern Martin, Aimee Mckane

U.S. Mine Ventilation Symposium

Every year the United States mining industry spends millions of dollars on underground ventilation systems. In the U.S., fan systems used for mine ventilation consume approximately 12,000 million kWh annually (Xenergy, 1997, 1998). Potential motor-driven system energy savings can be realized by using mature, proven, and cost-effective technologies. Such saving potentials exist in the mining industry and the U.S. Department of Energy's Motor Challenge program aims to assist the industry in capturing them. Energy efficiency upgrades can also achieve significant non-energy benefits such as better equipment reliability, longer equipment life, reduction in maintenance costs and downtime, and an improved working …

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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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A Comparison Of Air Leakage Prediction Techniques For Auxiliary Ventilation Ducting Systems, A. D. Stewart Gillies, Hsin Wei Wu Jun 1999

A Comparison Of Air Leakage Prediction Techniques For Auxiliary Ventilation Ducting Systems, A. D. Stewart Gillies, Hsin Wei Wu

U.S. Mine Ventilation Symposium

This paper briefly reviews prediction techniques for determination of leakage and friction along auxiliary ventilation ducting systems. In order to compare various prediction techniques that have been developed over the past, a macroscopic investigation of air leakage and friction resistance of auxiliary ventilation ducting systems has been undertaken. Measurements were conducted on 450 and 915 mm diameter fabric ducting over 100 m duct length to determine frictional resistances and the extent of leakage. Due to the high degree of accuracy required and the large volume of data that needed to be collected, electronic pressure transducers were used with computer for …

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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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Controlled Recirculation In Deep South African Gold Mines, Mark Butterworth Jun 1999

Controlled Recirculation In Deep South African Gold Mines, Mark Butterworth

U.S. Mine Ventilation Symposium

Despite the many advantages and potential benefits of using controlled recirculation in Deep South African gold mines the strategy has found little favour. Indeed, controlled recirculation of air is at present rarely considered as an option in the planning and implementation of these underground ventilation systems. This paper broadly examines controlled recirculation, the benefits and advantages that could accrue from its use, reasons that may detract from its use and some solutions for addressing shortcomings. A brief historical review of controlled recirculation in the context of the South African gold mining industry is given. The advantages, which could result from …

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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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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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Mining Safety Of Longwall Top-Coal Caving In China, Jian Wu, Yueping Qin, Minghua Zhai Jun 1999

Mining Safety Of Longwall Top-Coal Caving In China, Jian Wu, Yueping Qin, Minghua Zhai

U.S. Mine Ventilation Symposium

Longwall top-coal caving technology has developed rapidly in China, in recent years. The application of longwall top-coal caving can double both the productivity and the efficiency of a working face and reduce the cost of production by 30 to 40%. Using standard longwall equipment, annual production can reach 3 million metric tons (Mt), and a maximum of 4.1 Mt has been obtained; many top-coal caving longwall working faces can obtain 200 tons per man-shift. Longwall top-coal caving is distinctly different from slice mining in thicken seam. Concerns of safety and productivity for this method have been raised in recent years. …

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Ventilating The Box Cut Of A Two-Pass 40-Ft Extended Cut, Edward D. Thimons, Charles D. Taylor, Jeanne A. Zimmer Jun 1999

Ventilating The Box Cut Of A Two-Pass 40-Ft Extended Cut, Edward D. Thimons, Charles D. Taylor, Jeanne A. Zimmer

U.S. Mine Ventilation Symposium

On a continuous miner coal face methane concentrations are affected by the quantity of fresh intake air reaching the face. When mining the box cut on a 12.2-m (40-ft) two-pass extended cut face, the continuous miner is always at the point of deepest penetration, and operation of the machine-mounted dust scrubber and water spray system improve the flow of fresh air to the end of the box cut. However, when the continuous miner leaves the box cut to begin cutting the 40-ft slab, little is known about how much ventilation air reaches the end of the box cut. The Pittsburgh …

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Methane Concentration At Heading Faces With Auxiliary Ventilation, Shinji Tomita, Kenichi Uchino, Masahiro Inoue Jun 1999

Methane Concentration At Heading Faces With Auxiliary Ventilation, Shinji Tomita, Kenichi Uchino, Masahiro Inoue

U.S. Mine Ventilation Symposium

Three-dimensional airflow velocities at a heading face by a forcing or exhausting auxiliary ventilation system were measured in an actual size model gallery and in an actual mine. There were several stagnated regions near the roof comer, which might have danger of methane accumulation. Airflow velocities by an exhausting system were much smaller than that by a forcing system. The airflow and methane concentrations by a forcing, exhausting, or combined system were examined using a visualization technique by laser light in a reduced scale model. Water was used instead of air and very fine bubbles generated by electrolysis were employed …

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Dust Control At Yucca Mountain Project, Fred Kissell, Romeo Jurani, Ralph Dresel, Charles Reaux Jun 1999

Dust Control At Yucca Mountain Project, Fred Kissell, Romeo Jurani, Ralph Dresel, Charles Reaux

U.S. Mine Ventilation Symposium

This report describes actions taken to control silica dust at the Yucca Mountain Exploratory Studies Facility, a tunnel located in Southern Nevada that is part of a scientific program to determine site suitability for a potential nuclear waste repository. The rock is a volcanic tuff containing significant percentages of both quartz and cristobalite. Water use for dust control was limited because of scientific test requirements, and this limitation made dust control a difficult task. Results are reported for two drifts, called the Main Loop Drift and the Cross Drift. In the Main Loop Drift, dust surveys and tracer gas tests …

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Control Of Silica Dust In Slate Milling Operations, Karl T. Ahlen, Robert A. Haney, Joseph M. Denk Jun 1999

Control Of Silica Dust In Slate Milling Operations, Karl T. Ahlen, Robert A. Haney, Joseph M. Denk

U.S. Mine Ventilation Symposium

The Mine Safety and Health Administration (MSHA) conducted a study to assess the present state of technology used for controlling employees' respirable silica-bearing dust exposures during dimension slate milling operations. For this study, twelve slate milling operations were visited and various measurements were taken and observations made. These measurements and observations included exhaust and room airflow, types of enclosures, water usage, and building volumes for each of the milling processes. These mills usually employed between five and twenty people. From the study, general guidelines were developed from the best practices observed and can be used at the various sawing, splitting, …

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Measurements Of Dust Extraction Effectiveness On A Testing Stand, Walenty Frydel, Marcin Steindor Jun 1999

Measurements Of Dust Extraction Effectiveness On A Testing Stand, Walenty Frydel, Marcin Steindor

U.S. Mine Ventilation Symposium

The stand is used to determine characteristics of fans and dust collectors, especially their efficiency at different levels of dustiness of the air being cleaned. Both wet- and dry-dust collectors arc manufactured as experimental installations, prototypes products designed for industrial applications. The design of the research installation has been so elaborated that the installation is characterized by great flexibility in respect of its applicability, enabling both comparison tests and attestation tests to be carried out. The accepted programme of the basic research covers testing of dust collectors of vortex type equipped with rotors featuring axial, diagonal and radial flow as …

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Considerations For Estimating Remote Operator Dust Exposure Using Fixed-Point Samples On Continuous Mining Sections, Jeffrey M. Listak, Gerrit V. R. Goodman, Robert A. Jankowski Jun 1999

Considerations For Estimating Remote Operator Dust Exposure Using Fixed-Point Samples On Continuous Mining Sections, Jeffrey M. Listak, Gerrit V. R. Goodman, Robert A. Jankowski

U.S. Mine Ventilation Symposium

Respirable dust studies were conducted at several underground coal mining operations to evaluate and compare the dust measurements of fixed-point machine-mounted samples on a continuous miner and personal samples of the remote miner operator. Fixed-point sampling was conducted at the right rear corner of the continuous miner which corresponded to the traditional location of the operator's cab. Although it has been documented that higher concentrations of dust are present at the machine-mounted position, this work sought to determined whether a relationship exists between the concentrations at the fixed-point position and the dust levels experienced at the remote operator position and …

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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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Rapid Evaluation Of Rock Thermal Parameters At The Lucky Friday Mine, Ian J. Duckworth Jun 1999

Rapid Evaluation Of Rock Thermal Parameters At The Lucky Friday Mine, Ian J. Duckworth

U.S. Mine Ventilation Symposium

In many hot mines a large portion of the total heat load is associated with the surrounding strata. In order to maintain acceptable underground environmental conditions, the mine heat load must be controlled by the ventilating airstream, and in certain cases by mechanical refrigeration. To compute existing, or future heat additions from the surrounding rock, certain parameters must be -determined. These parameters include the rock thermal conductivity, thermal diffusivity, and the geothermal gradient (with relation to a virgin rock datum). These rock thermal parameters are typically estimated from published literature, or evaluated by laboratory or in-situ measurements. Presented in the …

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Control Of Heat And Humidity In German Mines, Wolfgang Schlotte Jun 1999

Control Of Heat And Humidity In German Mines, Wolfgang Schlotte

U.S. Mine Ventilation Symposium

In order to increase the economic efficiency of West European hard coal, great efforts are being made at present in the coal-producing countries to lower production costs. This aim is to be achieved in Germany, among other things, by a drastic increase in the saleable output per working face up to an average of 10,000 t/d in these cases where very long longwall faces (400 m ± 50 m) are possible. With the substantially greater heat input into the air stream which this involves, there is the danger that climatic limits will be exceeded even at longwall faces with lower …

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Method For Operative Prediction Of Sponcom Hazard In Gob Area, Michael Michaylov Jun 1999

Method For Operative Prediction Of Sponcom Hazard In Gob Area, Michael Michaylov

U.S. Mine Ventilation Symposium

Expert systems for SPONCOM risk assessment ·are used for choosing suitable fire-proof mining systems and ventilation schemes. Some of them can even estimate the effectiveness of planned ventilation and specific anti-fire measures for SPONCON risk reduction as early as at the design phase. The method proposed herewith is appropriate for operative evaluation of SPONCM risk in gob areas for the following three phases during longwall development: design stope, the commencement of production, and during production. Data from mine and model experiments and statistical data for the actual coal seams serve as a basis for defining index of relative SPONCOM risk …

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Evaluation Of Different Airflow Sensors At The Wipp Facility, Kirk Mcdaniel, Ian J. Duckworth, Brian S. Prosser Jun 1999

Evaluation Of Different Airflow Sensors At The Wipp Facility, Kirk Mcdaniel, Ian J. Duckworth, Brian S. Prosser

U.S. Mine Ventilation Symposium

The Waste Isolation Pilot Plant (WIPP) is an U.S. Department of Energy underground disposal facility designed to permanently and safely isolate U.S. defense-generated transuranic radioactive waste. The underground ventilation system is engineered to minimize the release of radioactive contamination to the environment in the event of an accident. During 1994 an extensive ventilation remote monitoring and control system was installed. It consists of fifteen air velocity sensors, eight differential pressure stations, automated control features on key underground air regulators, and eight psychrometric stations. The airflow monitoring component of the system has been a problem since the original installation. Due to …

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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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The General Characteristics Of Electromagnetic Radiation During Coal Fracture And Its Application In Outburst Prediction, Xue-Qiu He, En-Yuan Wang, Zhentang Liu Jun 1999

The General Characteristics Of Electromagnetic Radiation During Coal Fracture And Its Application In Outburst Prediction, Xue-Qiu He, En-Yuan Wang, Zhentang Liu

U.S. Mine Ventilation Symposium

Coal and methane outburst are catastrophic in coal mining, their prediction is difficult. In this paper, the electromagnetic radiation (EMR) generated during coal or rock deformation and fracturing is measured and analyzed. The results show that EMR truly exists during the fracture of coal or rock (with or without the presence of gas). It follows the Hurst statistical rule, and it basically exhibits gradually enhancing tendency during the process. The EMR strength and frequency are correlated to the coal or rock fracture process. Based on the experimental and theoretical studies, a new method for coal and methane outburst prediction is …

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Scale Tests, In-Situ Measurements And Simulation Of Methane Gas Distribution At Heading Faces, Shinsuke Nakayama, Masamoto Ichinose, Kenichi Uchino, Masahiro Inoue Jun 1999

Scale Tests, In-Situ Measurements And Simulation Of Methane Gas Distribution At Heading Faces, Shinsuke Nakayama, Masamoto Ichinose, Kenichi Uchino, Masahiro Inoue

U.S. Mine Ventilation Symposium

Distributions of methane gas concentration at a heading face with an auxiliary fan were measured in both an actual coal mine and a scale model. As a result, general distribution pattern of methane gas concentration was elucidated and it was found that there exist several areas where gas concentrations tend to rise to dangerous levels. A CFO (Computational Fluid Dynamics) method was also developed and the results of the computation were compared with those obtained in these measurements. It was concluded that the CFD can be used for simulating the distributions of gas concentration that are affected by conditions in …

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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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