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Articles 14101 - 14130 of 21750

Full-Text Articles in Engineering

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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Comparison Of Methane Concentrations At A Simulated Coal Mine Face During Bolting, Charles D. Taylor, Edward D. Thimons, Jeanne A. Zimmer Jun 1999

Comparison Of Methane Concentrations At A Simulated Coal Mine Face During Bolting, Charles D. Taylor, Edward D. Thimons, Jeanne A. Zimmer

U.S. Mine Ventilation Symposium

Strategies for monitoring methane levels during roof bolting in an extended cut entry were evaluated. Testing was conducted at the Pittsburgh Research Laboratory's methane test gallery. Operating conditions were varied and methane releases at the face and drill holes were simulated. Methane readings were taken at the face, and at locations outby the face. Results show that, when the major source of methane was at the drill holes, the highest methane readings were at locations on or 6.1 m (20 ft) inby the bolting machine. Methods for selecting better outby sampling locations, when the majority of the methane is released …

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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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Methods For Dust Removal In Roadway Sections, Walenty Frydel, Marcin Steindor, Robert A. Jankowski Jun 1999

Methods For Dust Removal In Roadway Sections, Walenty Frydel, Marcin Steindor, Robert A. Jankowski

U.S. Mine Ventilation Symposium

Systems for dust extraction in roadway workings subjected to suction or forced ventilation are a combination of dust collecting equipment and facilities designed for ventilating the working. Such a combination of suitable equipment provides safe and effective dust removal and ventilation of a roadway working as well as is determinant of proper cooperation of the equipment a system is composed of. The development of effective dust collectors of wet type which provide safe operation under conditions of great exposure to coal dust and methane explosion hazards as well as of vortex ventubes allowing methane accumulations under the roof to be …

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The Influence Of Coal Physical And Mechanical Properties And Mining Energy Consumption Factor On Airborne Respirable Dust Level, Antoni Koziel, Malgorzata Malec, Ewa Wardas Jun 1999

The Influence Of Coal Physical And Mechanical Properties And Mining Energy Consumption Factor On Airborne Respirable Dust Level, Antoni Koziel, Malgorzata Malec, Ewa Wardas

U.S. Mine Ventilation Symposium

The fact that there are not any explicitly defined relationships describing the influence of physical and mechanical properties of coal and of energy consumption factor on dust level prompted Polish and American investigators to carry out a joint research project within the framework of the U.S.- Poland Maria Sklodowska-Curie Joint Fund II. The paper presents methods used to perform tests under laboratory conditions at the Pittsburgh Research Laboratory as well as under real conditions in the course of coal cutting in polish coal mines. Measuring systems and results of the tests are described. The analysis carried out has provided a …

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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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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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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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The State Of Mining Research In Niosh, R. Larry Grayson Jun 1999

The State Of Mining Research In Niosh, R. Larry Grayson

U.S. Mine Ventilation Symposium

No abstract provided.

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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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Management Of Mine Explosion Risks, Jan J. L. Du Plessis, J. W. Oberholzer Jun 1999

Management Of Mine Explosion Risks, Jan J. L. Du Plessis, J. W. Oberholzer

U.S. Mine Ventilation Symposium

The management of explosions in the underground mining environment has been a high priority for managers since the turn of the century. In the early 1900s explosions, worldwide, reached catastrophic dimensions. In a number of large explosions more than 1000 people have died. In the early years of research, the basics of why explosions occurred were investigated and the participation of coal dust in underground coal mine explosions was proved. Taffanel, a French researcher, was one of the pioneers in establishing the use of stone dust and was instrumental in the design and development of the first stone-dust barriers. Throughout …

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Shock Waves Generated In The Presence Of Barriers In Gas Explosions, Baiquan Lin, Shining Zhou Jun 1999

Shock Waves Generated In The Presence Of Barriers In Gas Explosions, Baiquan Lin, Shining Zhou

U.S. Mine Ventilation Symposium

This paper examines conditions that generates shock waves in a gas explosion through experiment. The result shows that the presence of barrier and thin film, which is similar to air door and stopping in underground coal mines, is very important for the generation of shock waves in a gas explosion. When there are physical barriers, the speed of transmission would be very fast and shock waves will result in the process; when the film is destroyed in gas explosion, shock waves will also appear which would result in an increase in explosion power. Therefore, in order to weaken the gas …

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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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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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Anti-Stall Fans For The Mining Industry, Phil Blankenship, Hakan Bard, Robert Z. Smith Jun 1999

Anti-Stall Fans For The Mining Industry, Phil Blankenship, Hakan Bard, Robert Z. Smith

U.S. Mine Ventilation Symposium

Stable performance of mine ventilation fans is important not only for maintaining adequate ventilation of the mine, but also to maintain the integrity of the fan unit itself. It is demonstrated, herein, that a properly designed and applied stabilization device, integrated into the fan casing itself, will assure stable performance and actually extend the fan's capability.

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Improving The Ventilation Efficiency Of Jet Fans In Longitudinally Ventilated Rectangular Ducts, Eddy Jacques, Pierre Wauters Jun 1999

Improving The Ventilation Efficiency Of Jet Fans In Longitudinally Ventilated Rectangular Ducts, Eddy Jacques, Pierre Wauters

U.S. Mine Ventilation Symposium

The performance of a jet fan in a longitudinally ventilated tunnel is significantly reduced by the proximity of wall or ceiling where important shear stress losses occur. The paper focuses on the effect of jet fan inclination on the reduction of these losses; reducing losses means improved installation efficiency manifested by increased ventilation flow for the same fan power input. Experimental tests were carried out on a model at scale 1/5.5th. They allow one to determine the optimal jet pitch angle and the resulting benefit that could be drawn out of this solution in the case of tunnels …

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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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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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Validation Of Computational Models Of Auxiliary Ventilation Systems With Experimental Data, K. W. Moloney, D. M. Hargreaves, I. S. Lowndes, W. Pearce Jun 1999

Validation Of Computational Models Of Auxiliary Ventilation Systems With Experimental Data, K. W. Moloney, D. M. Hargreaves, I. S. Lowndes, W. Pearce

U.S. Mine Ventilation Symposium

This paper reports the interim findings of a research program whose objective is to determine whether Computational Fluid Dynamic (CFD) models can be employed to accurately predict the airflow patterns within rapid development headings. In particular, the project aims to investigate the optimum set back distances for the ducts in order to adequately ventilate the face of the drivage. To validate the accuracy of the CFD model simulations measurements were obtained from a series of experiments performed on both scale models and within a full-scale surface gallery. The experimental scale-modeling program included making a series of pressure measurements across the …

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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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Environ 2.5 — A Mine Ventilation And Cooling Network Simulation Tool, W. M. Marx Jun 1999

Environ 2.5 — A Mine Ventilation And Cooling Network Simulation Tool, W. M. Marx

U.S. Mine Ventilation Symposium

As mining operations progress, ore reserves are depleted and alternative are almost invariably found at increasing depth and a host of attendant difficulties in this regard face· the mine operator. Most significant among these is the control of the increasingly hostile environment encountered at depth in terms of both ground behaviour and the increasing hot environment. To enable the practical and economical design of mine ventilation and cooling systems, ventilation practitioners need effective and efficient tools to perform their duty. One such tool is the Environ 2.5, an interactive network simulation program that allows for the simultaneous simulation of airflow …

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Genetic Algorithm Optimization Of A Large U.K. Coal Mine Ventilation Network, Zhi-Yuan Yang, I. S. Lowndes, B. Denby Jun 1999

Genetic Algorithm Optimization Of A Large U.K. Coal Mine Ventilation Network, Zhi-Yuan Yang, I. S. Lowndes, B. Denby

U.S. Mine Ventilation Symposium

This paper reports on results of an application of a genetic algorithm to the optimisation of a large UK Coal Mine Ventilation Network. The genetic algorithm technique has been developed into a computer program for minimising the total network operating fan power costs. The application of booster fans may become an attractive alternative for ventilation engineers to provide an adequate supply of fresh air around the working areas in some deep and/or extensive mines. The objective of this research is to minimize the total power consumption of a ventilation system by determining the optimum combinations of (1) main fan and …

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