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Longwall Weighting Events At Phalen Colliery, Nova Scotia, Canada, Robert J. Macdonald
Longwall Weighting Events At Phalen Colliery, Nova Scotia, Canada, Robert J. Macdonald
Graduate Theses, Dissertations, and Problem Reports
Weightings are dynamic phenomenon observed 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 supports, and forces them to yield. A weighting event need not necessarily impact the mining process negatively, but notable cases exist where weightings have caused extensive damage to roof strata resulting in large roof falls and prolonged periods of lost coal production.;This thesis describes the history of four longwall panels (No's …
Design, Construction, And Evaluation Of Coal Extraction Pilot Plant To Manufacture Coal-Based Carbon Pitch, Brian Wayne Bland
Design, Construction, And Evaluation Of Coal Extraction Pilot Plant To Manufacture Coal-Based Carbon Pitch, Brian Wayne Bland
Graduate Theses, Dissertations, and Problem Reports
A solvent extraction technique for removing mineral matter, including the inorganic sulfur, from coal has been developed by the Department of Chemical Engineering at WVU. The extraction is preformed at mild conditions (202°C and atmospheric pressure) using the solvent N-Methyl-2-Pyrrolidone (NMP). Laboratory results have shown that this technique yields a clean coal product containing less than 1 percent ash and virtually no inorganic sulfur.;This research was conducted for further process design and economic development of an industrial-scale extraction process.;This research reported the possibility of production scale processing by constructing a pilot plant. The pilot plant was used to explore the …
Dynamic Property Evaluation Of Frother, Yunkai Xia
Dynamic Property Evaluation Of Frother, Yunkai Xia
Graduate Theses, Dissertations, and Problem Reports
Fourteen solvents were evaluated through frothing test and laboratory flotation batch tests. A new frothing parameter, initial dynamic froth index (IDFI), is proposed to compare the frothability of solvent. IDFI is derived from initial retention time of froth instead of retention time. IDFI is defined as the limiting slope of the initial retention time versus concentration curves while the concentration approaches zero. IDFI value depends on chemical structure and molecular weight of the solvent. Combined with normalized frothability index (NFI), normalized collapse rate constant (NKc), hydrophilic-lipophilic balance (HLB) and dynamic froth index (DFI), IDFI can be a useful index in …
Reliability-Based Method For Stability Of Mine Entry Design And Evaluation, Zhouming (Victor) Sun
Reliability-Based Method For Stability Of Mine Entry Design And Evaluation, Zhouming (Victor) Sun
Graduate Theses, Dissertations, and Problem Reports
Variability in the physical properties of coal/rock is a major source of uncertainty encountered around mining environment. It causes a considerable variation in strength/stress estimations of mining structures when the coal/rock properties are used. Therefore, the conventional safety factor method on stability assessment of mining structures is a special case of the more general probabilistic method in that it assumes the variability of coal/rock properties is zero. Although the use of probability and statistical methods in the analysis and design of geotechnical structures has grown rapidly in recent years, its application to mining structure design has been slow due to …
Relationship Between Cutting Parameters And Bit Geometry In Rotary Cutting, Srikanth Addala
Relationship Between Cutting Parameters And Bit Geometry In Rotary Cutting, Srikanth Addala
Graduate Theses, Dissertations, and Problem Reports
The main objective of this research was to investigate the relationship between cutting parameters (cutting force, penetration force, specific energy, specific respirable dust) and the bit geometry parameters (angle of the bit tip, bit tip size and shape of the bit) in order to reduce the amount of specific respirable dust generated and the specific energy consumed in rotary cutting. In the cutting process when two grooves are made in the rock at certain spacing, a land/ridge is formed between the two adjacent grooves. If that land/ridge can be removed in a cutting cycle, then a clean surface will be …
Iron And Acid Removal From Acid Mine Drainage In Open Limestone Systems, Qingyun Sun
Iron And Acid Removal From Acid Mine Drainage In Open Limestone Systems, Qingyun Sun
Graduate Theses, Dissertations, and Problem Reports
Passive systems, like wetlands, anoxic limestone drains, and open limestone channels, show promise for treating acid mine drainage (AMD) discharges. Open limestone channels have been developed for over ten years and the treatment effectiveness of AMD by open limestone systems shows wide variation. The variation is due to site conditions (slope and size of the limestone channel) but more importantly to the surface area of the limestone and iron concentrations in the water. Iron in AMD coats the limestone in open limestone systems thereby reducing the surface area available for reaction. Over time, the limestone appears to lose its ability …
Hydrogeologic Analysis Of Streamflow In Relation To Underground Mining In Northern West Virginia, David Robert Gill
Hydrogeologic Analysis Of Streamflow In Relation To Underground Mining In Northern West Virginia, David Robert Gill
Graduate Theses, Dissertations, and Problem Reports
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 panels, with two located over non-undermined areas. Discharge data shows that non-undermined watersheds do not experience stream dewatering, regardless of alluvium thickness or sediment size. Streams located over active or recently mined longwall panels experience water loss that ranges from slight to total. Impacted streams with overall increases in conductivity and decreases in water temperature suggest that lost streamflow travels …