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Articles 170161 - 170190 of 198087

Full-Text Articles in Engineering

Cfd Analysis Of Mine Fire Smoke Spread And Reverse Flow Conditions, J. C. Edwards, C. C. Hwang Jun 1999

Cfd Analysis Of Mine Fire Smoke Spread And Reverse Flow Conditions, J. C. Edwards, C. C. Hwang

U.S. Mine Ventilation Symposium

A Computational Fluid Dynamics (CFD) program was used to model buoyancy induced Product-Of-Combustion (POC) spread from experimental fires in the National Institute For Occupational Safety And Health (NIOSH), Pittsburgh Research Laboratory (PRL), safety research coal mine. In one application, the CFD program was used to predict spread from fires in an entry under zero airflow conditions. At a location, 0.41 m below the entry's roof at a distance of 30 m from the fire, the measured smoke spread rates were 0.093 and 0.23 m/s for a 30 and a 296 kw fire, respectively. The CFD program predicted spread rates of …

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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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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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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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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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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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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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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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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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Effectiveness Of Cabs For Dust And Silica Control On Mobile Mining Equipment, Joseph J. Garcia, Ronald E. Gresh, Mary Beth Gareis, Robert A. Haney Jun 1999

Effectiveness Of Cabs For Dust And Silica Control On Mobile Mining Equipment, Joseph J. Garcia, Ronald E. Gresh, Mary Beth Gareis, Robert A. Haney

U.S. Mine Ventilation Symposium

The Mine Safety and Health Administration (MSHA) has conducted a study to evaluate the effectiveness of cabs for controlling silica dust exposure during operation of mobile mining equipment. This study focused on bulldozers, front -end loaders and haul trucks, was conducted at surface coal mining operations and underground metal and nonmetal mining operations. Each piece of equipment tested was equipped with a cab. The vehicles sampled were from a range of manufacturers having different types of filter media and air intake configurations. The purpose of this study was to determine the reduction of dust and silica exposure that could be …

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Table Of Contents, Multiple Authors Jun 1999

Table Of Contents, Multiple Authors

U.S. Mine Ventilation Symposium

No abstract provided.

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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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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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Ventilation Optimization — Balancing The Need For More Power Against Environmental Concerns, Stephen G. Hardcastle, R. D. Lamond, D. T. Willoughby Jun 1999

Ventilation Optimization — Balancing The Need For More Power Against Environmental Concerns, Stephen G. Hardcastle, R. D. Lamond, D. T. Willoughby

U.S. Mine Ventilation Symposium

This paper shows how the Nanisivik mine was able to improve the underground working environment, decrease operational costs, and reduce its impact on the environment through optimizing their ventilation system. Through re-organizing their ventilation system, the overall flow through the mine increased by at least 20%, and local flows increased by over 100%. This change also resulted in a 45% reduction of fan motor power. And as a consequence of reduced power demands the mine has decreased its Green-house gas (GHG) emissions. Currently, ventilation is typically responsible for 40% of a Canadian mine's underground electrical consumption. This could dramatically change …

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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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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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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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Mathematical Description Of Air Cooling Using A Mining Diaphragm Cooler Taking Into Consideration The Condensation Of Water Vapour, Waclaw Dziunyński, Stanislaw Nawrat, Bernard Nowak, Janusz Roszkowski Jun 1999

Mathematical Description Of Air Cooling Using A Mining Diaphragm Cooler Taking Into Consideration The Condensation Of Water Vapour, Waclaw Dziunyński, Stanislaw Nawrat, Bernard Nowak, Janusz Roszkowski

U.S. Mine Ventilation Symposium

Taking into consideration the possibility of condensation of water vapour contained in air which flows through a diaphragm cooler, a mathematical model of space-time changes in air temperature, humidity, and also in the temperature of the heat exchanger and the cooling water in the cooler in question was created. In the mathematical description of air-cooling using the above-mentioned cooler two zones was identified. The first concerns the dry cooling of air, while within the second, the process of outdropping of water contained in the cooled air. Each of these zones has been described by applying a system of three partial …

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Rapid Extinguishing Of Sponcom Fires In Underground Mines, Zygmunt Kajdasz, George Zieba Jun 1999

Rapid Extinguishing Of Sponcom Fires In Underground Mines, Zygmunt Kajdasz, George Zieba

U.S. Mine Ventilation Symposium

The main purpose presented in this paper is to present active and passive methods to fight a sponcom fire. The active method uses an inert gas generator called the GAG while the passive method is through the use of ventilation software. In most sponcom situations a combination of these two methods results in rapid extinguishing of the overheated areas. The presented software allows for accurate and "real time" analysis of the ventilation network. Application of the GAG has been proven on many occasions as an effective means of large volumes of mine atmosphere.

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Recovery Of Minerales Monclova Minas V, Patrick Graham, William Marston, Donald Mitchell, John W. Stevenson, David Sullivan Jun 1999

Recovery Of Minerales Monclova Minas V, Patrick Graham, William Marston, Donald Mitchell, John W. Stevenson, David Sullivan

U.S. Mine Ventilation Symposium

Methane issuing from a roof-bolt hole ignited when the hot bit was withdrawn. Similar ignitions have occurred in other mines. This one differed in that flames spread quickly, coal was ignited, and, after three futile hours of applying inadequate water and extinguishing agents, the mine was sealed. Fires are fuel and ventilation controlled. In this mine there was an abundance of methane, coal, and wood lagging. Recovery of the mine, therefore, depended on successful control of its ventilation. The recovery was done without anyone suffering a scratch; a remarkable feat considering the abnormal methane outflows and concentrations, the continuing evidence …

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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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Axial Flow Fan Use At San Manuel Mine, Kuda R. Mutama, Dave P. Pelletier Jun 1999

Axial Flow Fan Use At San Manuel Mine, Kuda R. Mutama, Dave P. Pelletier

U.S. Mine Ventilation Symposium

A case study is presented for the use of multiple axial flow main fans as the principle source of the primary mine ventilation system for a large multi level mine. Formerly owned by Magma Copper, BHP Copper Inc.'s San Manuel Mine is a large underground block caving copper mine which started producing copper in 1955. The San Manuel Mine produces over 50,000 tons per day sulfide copper ore. The total airflow into this mine is approximately 800 m3/s (1,600,000 cfm). Providing adequate ventilation has been a very challenging experience as new, deeper levels are developed. BHP relies on …

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