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Articles 14041 - 14070 of 21750

Full-Text Articles in Engineering

Parametric Study Of Unsteady-State Flow Modulation In Trickle-Bed Reactors, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković Jul 1999

Parametric Study Of Unsteady-State Flow Modulation In Trickle-Bed Reactors, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

Unsteady-State Liquid Flow Modulation (Periodic Operation) Was Investigated for Hydrogenation of Alpha-Methylstyrene to Cumene in a Hexane Solvent over 0.5% Pd on Alumina Spheres. This Test Reaction Was Run under Both Gas and Liquid Reactant-Limited Conditions. It is Shown that Periodic Liquid Flow Modulation Can Alter the Supply of Liquid and Gaseous Reactants to the Catalyst and Result in Reactor Performance Different from that Obtained under Steady-State Conditions. the Effect of Key Parameters Such as Extent of Gas/liquid Limitation, Total Cycle Period, Cycle Split, and Liquid Mass Velocity Were Investigated Experimentally to Demonstrate the Cause-Effect Relationships in Periodic Operation. Performance …

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Manufactured Gas In California, 1852-1940: Basis For Remedial Action, Allen W. Hatheway Jul 1999

Manufactured Gas In California, 1852-1940: Basis For Remedial Action, Allen W. Hatheway

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

California was a relatively late entry (1852) in the manufactured gas industry. However, its gas entrepreneurs showed considerable invention and enterprise in establishing more than 250 separate gas plants, this in a total geographic environment approximating a whole nation of separate-operating and now environmentally endangering, conditions. Virtually all of the many gas generation processes and patent variations were employed in the state, and a wide variety of geologic conditions have created an even wider variety of fate and transport conditions related to their far and other residuals. A complex development of holding companies and other management forms also need interpretation …

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A Blind Deconvolution Approach For Resolution Enhancement Of Near-Field Microwave Images, Ali Mohammad-Djafari, Nasser N. Qaddoumi, R. Zoughi Jul 1999

A Blind Deconvolution Approach For Resolution Enhancement Of Near-Field Microwave Images, Ali Mohammad-Djafari, Nasser N. Qaddoumi, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper we propose a blind deconvolution method to enhance the resolution of images obtained by near-field microwave nondestructive techniques using an open ended rectangular waveguide probe. In fact, we model such images to be the result of a convolution of the real input images with a point spread function (PSF). This PSF depends mainly on the dimensions of the waveguide, the operating frequency, the nature of the object under test and standoff distance between the waveguide and the object. Unfortunately, it is very difficult to model this PSF from the physical data. For this reason, we consider the …

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The Effect Of Platinum And Excess 211 Phase On The Loss Of The Liquid Phase In Melt Textured Yba2cu3o7-X, William C. Hicks, Fatih Dogan, M. Strasik, A. C. Day, Kevin E. Mccrary Jun 1999

The Effect Of Platinum And Excess 211 Phase On The Loss Of The Liquid Phase In Melt Textured Yba2cu3o7-X, William C. Hicks, Fatih Dogan, M. Strasik, A. C. Day, Kevin E. Mccrary

Materials Science and Engineering Faculty Research & Creative Works

Platinum is an important additive in YBa2Cu3O7-x [123] powders for melt processing and growth of large, oriented crystals, but its role in liquid loss during the growth cycle is poorly understood. A series of experiments were conducted to determine how platinum effects liquid loss, and to study the solubility limit of platinum in 123. Both atomically mixed and solid state platinum sources were compared. Crystals were grown on a nonreactive setter so that liquid loss could be clearly distinguished by weight from reaction products with the setter. Based on weight loss studies there was little …

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The Effect Of Platinum And Excess 211 Phase On The Loss Of The Liquid Phase In Melt Textured Yba₂Cu₃O₇₋ₓ, William C. Hicks, Fatih Dogan, Michael Strasik, Arthur C. Day, Kevin E. Mccrary Jun 1999

The Effect Of Platinum And Excess 211 Phase On The Loss Of The Liquid Phase In Melt Textured Yba₂Cu₃O₇₋ₓ, William C. Hicks, Fatih Dogan, Michael Strasik, Arthur C. Day, Kevin E. Mccrary

Materials Science and Engineering Faculty Research & Creative Works

Platinum is an important additive in YBa2Cu3O7-x [123] powders for melt processing and growth of large, oriented crystals, but its role in liquid loss during the growth cycle is poorly understood. A series of experiments were conducted to determine how platinum effects liquid loss, and to study the solubility limit of platinum in 123. Both atomically mixed and solid state platinum sources were compared. Crystals were grown on a nonreactive setter so that liquid loss could be clearly distinguished by weight from reaction products with the setter. Based on weight loss studies there was little …

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The Effectiveness Of An On-Line Graduate Engineering Management Course, Rosemarie Maffei Evans, Madison Daily, Susan L. Murray Jun 1999

The Effectiveness Of An On-Line Graduate Engineering Management Course, Rosemarie Maffei Evans, Madison Daily, Susan L. Murray

Engineering Management and Systems Engineering Faculty Research & Creative Works

In the summer of 1997, the Engineering Management Department of the University of Missouri-Rolla's (UMR) began offering its first Internet-based graduate level course. This course, Advanced Production Management, was designed to utilize a combination of Internet-based tools, such as EMail and Chat rooms to create a alternative means for the delivery of course material. This paper will draw these following conclusions from more than a year of research, which included over 100 students in six different course offerings. First, the Internet-based students performed equally as well as the control group students. Second, students tend to have exaggerated time requirement expectations …

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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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Gas Emission Control On Longwall Panels At The Vorkuta Coal Mines, V. N. Bobrovnikov, O. I. Kazanin, A. P. Veselov Jun 1999

Gas Emission Control On Longwall Panels At The Vorkuta Coal Mines, V. N. Bobrovnikov, O. I. Kazanin, A. P. Veselov

U.S. Mine Ventilation Symposium

The characteristics of geological conditions and mining technology at the coal mines of Coal Stock Company Vorkutaugol are given in the article. Information about longwall panel ventilation schemes and problems caused by high methane emission is also presented. The results of experiments at longwall panels using the methane emission control ventilation complex are described as well as ways of isolating gob methane removal. Other topics include the methane emission control ventilation complex consisted of drainage entry, an isolating wall with windows, mixing chambers and regulating stoppings. As results of experiments have shown, the most effective gas emission control methods were: …

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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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Lowering Respirable Dust Exposures At Mineral Processing Facilities, Andrew B. Cecala, Robert J. Timko, Edward D. Thimons Jun 1999

Lowering Respirable Dust Exposures At Mineral Processing Facilities, Andrew B. Cecala, Robert J. Timko, Edward D. Thimons

U.S. Mine Ventilation Symposium

This article discusses three research projects performed by the National Institute for Occupational Safety and Health, (formerly the Bureau of Mines), that reduce the respirable dust exposure of plant workers at mineral processing facilities. All three of these projects are very different but they all have the same goal of reducing worker exposure to respirable dust at mineral processing facilities. The first project deals with a total mill ventilation system that reduces dust levels throughout an entire building and lowers the dust exposure of everyone working in the structure. The second project describes a bag and belt cleaner device that …

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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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Personal Cooling In Hot Workings, Michael A. Tuck Jun 1999

Personal Cooling In Hot Workings, Michael A. Tuck

U.S. Mine Ventilation Symposium

The number of mines experiencing climatic difficulties worldwide is increasing. In a large number of cases these climatic difficulties are confined to working areas only or to specific locations within working areas. Thus the problem in these mines can be described as highly localised, due to a large extent not to high rock temperatures but due to machine heat loads and low airflow rates. Under such situations conventional means of controlling the climate can be inapplicable and/or uneconomic. One possible means of achieving the required level of climatic control, to ensure worker health and safety whilst achieving economic gains, is …

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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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The Practice Of Ventilation Planning Half A Century Ago, Rudolf E. Greuer Jun 1999

The Practice Of Ventilation Planning Half A Century Ago, Rudolf E. Greuer

U.S. Mine Ventilation Symposium

This is the description of ventilation planning conducted by the author in 1952 as his thesis for the German degree of Dipl.-Ing. Since the problems have not changed, most of the work done is not much different from what one would do today. Even the tools have remained the same, except for the computers, which were not around yet. To compensate for this, certain planning techniques were developed which are now in danger of being forgotten.

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Cfd Applications In Tunnel Ventilation Analysis, Richard E. Ray Jr., Abdelgbani Zigh Jun 1999

Cfd Applications In Tunnel Ventilation Analysis, Richard E. Ray Jr., Abdelgbani Zigh

U.S. Mine Ventilation Symposium

Longitudinal ventilation systems in transit and rail tunnels are typically analyzed by one dimensional ventilation network simulation models, such as the Subway Environment Simulation (SES) program. However, in recent years computational fluid dynamics (CFD) modeling has been utilized in conjunction with one-dimensional ventilation network programs to study ventilation systems for large volume spaces such as transit stations and rail overbuilds, as well as for vehicular tunnels. CFD uses numerical methods to simulate complex fluid flow phenomena in three dimensions to predict the distribution of velocity, pressure, temperature, concentration, and other relevant variables throughout the volume. This paper presents an overview …

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Developments In Longwall Ventilation, Jürgen F. Brune, Joseph P. Aman, Mike Kotch Jun 1999

Developments In Longwall Ventilation, Jürgen F. Brune, Joseph P. Aman, Mike Kotch

U.S. Mine Ventilation Symposium

Rapid development in longwall mining technology has brought significant changes in panel layout and geometry. These changes require adaptations in the ventilation system to provide sufficient air quantities in longwall face and bleeder areas. At CONSOL, various longwall bleeder systems in the Pittsburgh No. 8 Seam have been studied with detailed ventilation surveys. Computer model network simulations were conducted from these surveys to study the effects of different bleeder configurations and ventilation adjustments. This paper examines the relationships between the longwall face air quantity and the convergence in the tailgate-to-bleeder entries, number of development entries, bleeder fan pressure and the …

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Replacement Of A Major Ventilation Raise At The Homestake Gold Mine, Justus B. Deen, John R. Marks, Leetta M. Shaffner Jun 1999

Replacement Of A Major Ventilation Raise At The Homestake Gold Mine, Justus B. Deen, John R. Marks, Leetta M. Shaffner

U.S. Mine Ventilation Symposium

Few tasks are more important to the Ventilation Engineer than planning major airways. This paper presents a case study of the inception, design, installation, cost and performance of a 253 m long, 4.27 m diameter subsurface replacement exhaust raise and its connecting drifts. The original raise served as a component of the primary exhaustway (140 m3/s) and heat rejection sink (8MW) for the deepest production district, responsible for 45% of the mine's total ounce production. The chronology of ground control problems with the original raise and attempts to halt the unraveling are described. Planning for a replacement raise commenced once …

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Effects Of Drilling Small Diameter Exhaust Shafts In A Gassy Longwall Operation, Tim Coleman, William Maloney Jun 1999

Effects Of Drilling Small Diameter Exhaust Shafts In A Gassy Longwall Operation, Tim Coleman, William Maloney

U.S. Mine Ventilation Symposium

As the title indicates, this paper deals with the ventilation of a gassy longwall mine through the use of small diameter exhaust shafts. Extensive background information is provided to show the evolution of the mine's ventilation system to correspond with changes in longwall mining techniques, particularly increases in face width. A description of the blind drilled shaft techniques, which proved to be the most economical ventilation choice for US Steel No. 50 Mine, is also included.

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Ventilation-On-Demand: Quantity Or Quality — A Pilot Trial At Barrick Gold's Bousquet Mine, Stephen G. Hardcastle, M. K. Gangal, Manfred Schreer, Paul Gauthier Jun 1999

Ventilation-On-Demand: Quantity Or Quality — A Pilot Trial At Barrick Gold's Bousquet Mine, Stephen G. Hardcastle, M. K. Gangal, Manfred Schreer, Paul Gauthier

U.S. Mine Ventilation Symposium

Common to many established mines in Canada, is the problem that their ventilation systems are continually being stretched to meet new needs that were not anticipated in the original design. This can be the result of a variety of different factors, such as the discovery of new reserves at depth, accelerated production, new worker exposure regulations or a change of mining method. At Bousquet, the ventilation of a new multilevel mining block over 1 km away from the existing bottom of the mine presents a challenge. The airflow available for this region is limited to 57 m3/s by …

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Novel Approach To The Energy Analysis Of Mine Cooling Strategies, C. T. Twort, I. S. Lowndes, S. J. Pickering Jun 1999

Novel Approach To The Energy Analysis Of Mine Cooling Strategies, C. T. Twort, I. S. Lowndes, S. J. Pickering

U.S. Mine Ventilation Symposium

The extraction of minerals and coal at increasing depth, employing higher-powered, mechanized machinery to increase production levels imposes an increased burden on the ability to maintain an acceptable mine climate. Any deterioration in the mine climate within working zones may adversely affect the health and safety of the workforce. The combination of the optimal design of the mine system layout, together with the selective application of suitable ventilation and cooling systems, may be used to control the climate within working zones. The adoption of mechanical cooling within mines is an expensive process in terms of both capital and operating costs. …

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Performance Assessment Of A Multi-Stage Cooling System At San Manuel Mine, Kuda R. Mutama Jun 1999

Performance Assessment Of A Multi-Stage Cooling System At San Manuel Mine, Kuda R. Mutama

U.S. Mine Ventilation Symposium

This paper describes the mine ventilation cooling system at San Manuel Mine, which has evolved as new deeper and hotter working levels were added to the mine, between 1979 -1997. The expansion philosophy was based on utilizing existing facilities, providing lower capital cost and operational convenience. The cooling system is comprised of three surface chillers of 10.55 Megawatts (3,000 tons) total cooling capacity. Cooling towers, also located on surface, ultimately reject all the heat from underground system. The chilled water is pumped to a shell and tube heat exchanger station located 915 metres underground in a high pressure circulating water …

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Three Underground Coal Mine Explosions — Twenty Miners Killed — One Reason, Andrzej M. Wala, Jason R. Stoltz Jun 1999

Three Underground Coal Mine Explosions — Twenty Miners Killed — One Reason, Andrzej M. Wala, Jason R. Stoltz

U.S. Mine Ventilation Symposium

Three mine explosions which occurred in the 1980s (1983 - McClure No. 1 Mine, Virginia; 1984 - Greenwich Collieries No. 1 Mine, Pennsylvania; and 1989- Pyro No.9 Slope Williams Station Mine, Kentucky) cost twenty lives. The authors, by investigating these three cases, found a common ventilation problem. This problem was the misunderstanding of the diagonal connections in the mine ventilation system (MVS). Based on the findings from these investigations, the authors explain the importance of diagonal connections in a MVS and discuss other factors that affected safety.

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On Criteria Of Stability Of Fans Operating In Parallel, Jerzy Krawczyk Jun 1999

On Criteria Of Stability Of Fans Operating In Parallel, Jerzy Krawczyk

U.S. Mine Ventilation Symposium

Ventilation systems with fans operating in parallel may have multiple operating points. The submitted paper presents a method which enables to reduce the number of points which should be taken into consideration. The concepts of a fan system containing: the fan, inlet duct, regulation door subsystem and its total characteristics were introduced. The analysis of local stability of equilibrium points of the system of ordinary differential equations describing unsteady incompressible flow in a simplified network ventilated by 2 fans in parallel leads to formulation of a simple condition of stability. For fans operating in parallel this condition refers to the …

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Expert System For Mine Supervising Staff Fire Hazard Monitoring And Fire - Fighting, Waclaw Dziurzynski, Stanislaw Wasilewski Jun 1999

Expert System For Mine Supervising Staff Fire Hazard Monitoring And Fire - Fighting, Waclaw Dziurzynski, Stanislaw Wasilewski

U.S. Mine Ventilation Symposium

The paper presents the functions of an expert system designed for mine supervising staff responsible for fire hazard monitoring and fire-fighting. The essence of the system is to gather the complete data from hazard monitoring systems and the results of manual measurements made by ventilation staff in a common database. The database can be used for analysis and engineering calculation employed in mine ventilation supervision and also for the prevention against natural hazards, in particular fire and methane. Hardware and software tools developed within the framework of the system will also be used during rescue operation.

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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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Radiological Modelling Software For Underground Uranium Mines, Brian Bjorndal, Reza Moridi Jun 1999

Radiological Modelling Software For Underground Uranium Mines, Brian Bjorndal, Reza Moridi

U.S. Mine Ventilation Symposium

The Canadian Institute for Radiation Safety (CAIRS) has been developed computer simulation software for modelling radiological parameters in underground uranium mines. The computer program, called 3d RAD, allows radiation protection professionals and mine ventilation engineers to quickly simulate radon and radon progeny activity concentrations and potential alpha energy concentrations in complex mine networks. The simulation component of 3d RAD, called RSOL VER, is an adaptation of an existing modelling program called VENTRAD, originally developed at Queen's University, Ontario. Based on user defined radiation source terms and network physical properties, radiological parameters in the network are calculated iteratively by solving Bateman's …

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Optimization Of The Ventilation System At Kidd Mine Of Falcon Bridge Limited, Josef Sedlacek Jun 1999

Optimization Of The Ventilation System At Kidd Mine Of Falcon Bridge Limited, Josef Sedlacek

U.S. Mine Ventilation Symposium

Kidd Mine is the single largest producing base metal mine of Falconbridge Limited. Approximately 3 million tonnes of zinc-copper ore is produced annually. The present ventilation system, designed some 30 years ago, uses a multitude of intake and exhaust fans, in a series-parallel configuration, to move 925 m3/s (2,000,000 cfm) through the mine. The system, owing to the ever increasing depth of mining, has reached its limitation and has become cumbersome to maintain. It was recognized that with the mine progressing from the original depth of 855 m (2800 ft) to the current depth of 2070 m (6800 …

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Water Injection In Longwall Top-Coal Caving Face In China, Zhang Yong, Fu Gui Jun 1999

Water Injection In Longwall Top-Coal Caving Face In China, Zhang Yong, Fu Gui

U.S. Mine Ventilation Symposium

This paper discussed the means of improving dust control efficiency using water injection. At first, the authors point out that internal water has effect on dust control. The objective of water injection is to increase the amount of internal water. Secondly, by analyzing the development trend of crack in top-coal, proper water injection station and boleholes can be determined for dust control.

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Increased Methane Emissions For Mechanical Miners Working In Burnt Coal, A. P. Cook Jun 1999

Increased Methane Emissions For Mechanical Miners Working In Burnt Coal, A. P. Cook

U.S. Mine Ventilation Symposium

An intensive research programme has quantified the methane conditions around mechanical miners in production conditions. Methane seam gas contents show an increase of up to 26 times when mining burnt coal compared with normal increase in emission rates. Coal seam methane contents at the face increased from 1 m3/t to 6m3/t in one section, and from 0.1 m3/t to 2.6 m3/t in another. Emission rates from burnt coal were as high as 300 lit/min as it was mined. These increases in content and emission occur immediately after cutting into the burnt coal. …

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