Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 18 of 18 for “"longwall mining"”.
-
Stochastic availability analysis and modeling of longwall mining operations
… assessment and prediction of the availability of longwall mining systems. After a functional analysis of longwall mining operations, the longwall production system is divided into four subsystems: coal—cutting, face—conveying, roof—support, and outby—haulage. The operating characteristics of the …
-
Design and stability of barrier pillars in longwall mining
… this study to model single- and double-entry longwall systems. The influence of the geology, mining depth and mine-layout on barrier pillar stability was examined and design guidelines for determining sizes for such pillars were established using the "pillar core concept". The yield zone was …
-
Longwall mining, subsidence, and protection of water resources in Virginia
… methods. However, subsidence caused by Iongwall mining has been blamed for, among other things, damaging wells, springs, and streams above the mines. Surface landowners whose water supplies are affected by Iongwall mines may negotiate with mining companies for compensation, or they can seek …
-
Improvement of Ground-Fault Relaying Selectivity through the Application of Directional Relays to High-Voltage Longwall Mining Systems
The continuing trend toward larger longwall mining systems has resulted in the utilization of higher system voltages. The increase in system voltage levels has caused the industry to face complexities not experienced with the lower-voltage systems. One such complexity arises from the larger system …
-
Surface Subsidence Due to Coal Mining in Illinois
… the land surface has been associated with coal mining in Illinois since the early days of the industry. Investigations of subsidence damage began in Illinois more than 100 years ago. However, over the years there has been very little scientific or engineering documentation of subsidence …
-
Investigation, Analysis, and Modeling of Longwall Face-to-Face Transfers
… efforts to investigate, analyze, and model longwall face-to-face transfers through the use of operations research techniques. The purpose is to reduce overall transfer time and the variation of transfer times among operations within the U. S. longwall industry. The research includes: (1) …
-
Longwall weighting events at Phalen Colliery, Nova Scotia, Canada
… in mines where coal is extracted using the longwall mining method. Weightings are characterized by high convergence rates within the powered supports which maintain roof stability along the longwall face. Rapid convergence is induced by ground pressures that exceed the load capacity of the …
-
Hydrogeologic analysis of streamflow in relation to underground mining in northern West Virginia
Land subsidence, caused by longwall mining, has a negative effect on overlying watersheds. Nine streams were monitored from their headwaters to their mouths for discharge, temperature, conductivity, alluvium thickness, and alluvium sediment size. Seven streams are located over undermined longwall …
-
Factors considered for increasing longwall panel width
Longwall mining is the preferred method in coal mining to maximize production and reserve recovery by extracting large blocks of coal that have been outlined with a set of continuous miner development entries. In the US, technological advances and system enhancements have steadily improved …
-
AN IMPROVED ROCK MASS BEHAVIOR NUMERICAL MODEL AND ITS APPLICATIONS TO LONGWALL COAL MINING
… BEHAVIOR NUMERICAL MODEL AND ITS APPLICATIONS TO LONGWALL COAL MINING The rock mass constitutive models should include elastic moduli, strength and stiffness of intact rock as well as those of joints and geometric properties of joints. The post-failure behavior of intact rock and joints must also …
-
The prediction of surface subsidence due to room and pillar mining in the Appalachian coalfield
… to domestic as well as foreign experiences with longwall mining. Investigations into room-and-pillar subsidence have often been neglected, despite the fact that this is the predominant mining system in this country. However, the recent economic incentives which have caused the need for higher …
-
Four-Dimensional Passive Velocity Tomography of a Longwall Panel
… mine in the western United States, utilizing longwall mining. The mine has experienced rockbursts. Seismic data were collected over a nineteen day period, from July 20th, 1997 to August 7th, 1997, although only eighteen days were recorded. Instrumentation consistsed of sixteen receivers, …
-
CFD modeling of a tailgate ventilation condition in a longwall bleeder system
Face ignitions at the longwall are a serious hazard in underground coal operations and can lead to a major mine explosion. Despite having methane monitoring systems mounted on the shearer and at various locations on the longwall face, undetected methane accumulations can still occur and result in …
-
Applications of Surface and Subsurface Subsidence Theories to Solve Ground Control Problems
… models to simulate the ground response to mining and solve the ground control problems associated with it.;During the last four decades, many research works have been conducted on the ground control study, and numerous models, including analytical, empirical, numerical and hybrid models, …
-
Approaches to Simulation of an Underground Longwall Mine and Implications for Ventilation System Analysis
… is critical to the safe operation of underground longwall mines. Currently, there are several options for simulation of mine ventilation. This research was conducted to rapidly simulate an underground longwall mine, especially for the use of tracer gas in an emergency situation. In an emergency …
-
Monitoring Underground Mine Displacement Using Photogrammetry and Laser Scanning
… change behavior with installation, may obstruct mining operations, and are restricted to monitoring the behavior of a small area. Photogrammetry and laser scanning offer the ability to monitor rock mass movements at millions of points in a local area, both accurately and quickly. An improved, or …
-
Battle of the Bulls: A Coal Conflict in Cattle Country
… to cope with the onset of underground coal mining. For 40 years, the Charter family fought to prevent coal mining on their land in southern Musselshell County. In February, the federal government leased the remaining coal under their property to the mining company. As the Charters experience …
-
Battle of the Bulls: A Coal Conflict in Cattle Country
… to cope with the onset of underground coal mining. For 40 years, the Charter family fought to prevent coal mining on their land in southern Musselshell County. In February, the federal government leased the remaining coal under their property to the mining company. As the Charters experience …