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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Attitude toward surface mining for coal and reclamation in Ohio : a spatial analysis.

Ray, John Robert January 1972 (has links)
No description available.
172

Property rights in the coal industry: efficiency and legal change

Machnic, John A. January 1983 (has links)
This dissertation is a study of the development of property rights in the coal industry as defined by Federal legislation. Previous analyses have argued that property rights develop efficiently and have employed a neoclassical model to study this development in the political market. This study asserts that the neoclassical model is inappropriate for analyzing the political market. This study concentrates on the coal industry, analyzing the historical events surrounding development of the property rights structure. A price theoretic approach is employed to determine whether changes in the property rights structure results in greater efficiency for the coal industry. The evidence provided in the study does not support use of the neoclassical model. The model is too constrained and does not allow the inclusion of nonmarket factors in the analysis. / Ph. D.
173

A study of problems encountered in multiple-seam coal mining in the eastern United States

Stemple, David Townsend January 1955 (has links)
M.S.
174

A survey of the factors which affect mining of the lower Mississippian coals in Montgomery County, Virginia

Stevens, David Woods January 1959 (has links)
"Factors Which Affect Mining of the Lower Mississippian Coals in Montgomery County, Virginia" ie a study ot the Merrimac and Langhorne seams of the Price formation in Montgomery County, Virginia. The main reference used in the review of literature was Bulletin XXV of the Virginia Geolog1cal Survey by Marius R. Campbell. The review of literature discusses geologic formations and structure and the coal as seen in various prospect and mine openinga by Campbell. The author visited mines during the field investigation and analyzed samples of coal collected at the mines. He discusses past mining operations in Montgomery County and has traced all available mine maps of past mining operations. These are filed as part of the thesis. Core drillings were also investigated by the author and reported depths of the coal in the Blacksburg syncline ere entered in Table III and Figure I. An investigation was also made into mining methods used in Montgomery County including a discussion of explosive gases encountered in mining the Merrimac seam. The author discusses the results of the investigation in the conclusions. Be ia convinced the coals of the Valley fields, although of poor quality, will becane increasingly valuable as anthracite deposit in Pennsylvania and bituminous deposits in Southern West Virginia and southwest Virginia are depleted. / Master of Science
175

A study of the mineralogy of roof and floor strata associated with coal mines

Fisher, Frank Tasman 08 September 2012 (has links)
The first conclusion that can be drawn from these results is the extreme variation in the size distribution of the particles of the material. Table nine shows the maximum, average and minimum percents of each size found in the roof shales, and table ten shows the same factors for the floor clays. From the reported answers to question A we can also see the wide range of opinion concerning roof shales. Of those materials classed as slate, the sand size varied from 1 to 64 percent, while the material reported as draw-slate fell between these limits with a range of sand size from 3 to 38 percent. / Master of Science
176

Model development, testing and computer implementation for a coal blending and distribution problem

Puri, Ritu 22 October 2009 (has links)
This thesis is concerned with the study of typical coal flow operations in the coal industry, with a concentration on the blending and distribution problems. Westmoreland Coal Company at Big Stone Gap, VA serves as the basis for our study. The problem here is to determine decisions and schedules for coal shipment to silos, cleaning and blending operations at silos, and the subsequent shipment of coal to customers over a multi-period time horizon, so as to satisfy the demand at a minimum operational cost. Three linear programming models of varying complexity and capability are developed to meet this objective. The final product is a computer-based decision tool which will serve as a mechanism for implementing cost-effective decisions in light of complex variations in production, ore quality, and demand requirements over time. The models can be used to plan future growth and capital investment decisions, as well as to study the effect of various policies, by testing the sensitivity, feasibility, and the cost of system operations under different perturbations of system configuration, data, and demand specifications. Real operational data from the Westmoreland Coal Company is used for testing purposes. / Master of Science
177

Strategic and tactical models and algorithms for the coal industry under the 1990 Clean Air Act

Saifee, Quaid J. 29 September 2009 (has links)
This thesis is concerned with a study of the effect of The Acid Rain Provision of the 1990 Clean Air Act on the investment, production, and distribution operations in the coal industry, with a concentration on the development of new mines, shutting down of inefficient strips of existing mines, and on blending and distribution problems. The problem here is to determine which new mines to open and when, and what decisions and schedules to make for the shipment of coal from mines to silos, cleaning and blending operations at silos, and the subsequent shipment of coal to customers over a multi-period time horizon, so as to satisfy the demand at a minimum total operational cost. To meet this objective, a long-term strategic model is developed, and is coordinated with a modification of a short-term tactical model developed by Sherali and Puri (1991). The final product is a computer-based decision tool which will serve as a mechanism for implementing cost effective decisions in light of complex variations in the production levels of existing and potential mines, ore quality, and demand and quality requirements. The strategic model will play a useful role in planning future growth and in making capital investment decisions, and the tactical model will help in making better operational decisions. The models can also be used to study the effect of various policies, by testing the sensitivity, feasibility, and the cost of system operations under different perturbations of system configuration, data, and demand specifications. Real operational data and future projections from the Westmoreland Coal Company are used for testing purposes. / Master of Science
178

Application of water mist to fuel-rich fires in model coal mine entries

Loomis, Ian Morton 10 January 2009 (has links)
As the nature of coal mInmg changes, to higher production associated with higher mechanization, the way in which mine safety is approached must also change. This situation was clearly shown in a very devastating coal mine fire in late 1984. In the absence of effective fire-fighting procedures and equipment the affected mine was quickly rendered helpless. Of particular concern with coal mine fires is the possibility of entering a fuel-rich state. In this state current practices have proven to be of little use in gaining control over the conflagration. Recent experiences with the application of water mist to industrial fires has shown that use of fog can be an efficacious agent in controlling large scale fires. The postulations of this phenomenon concern the ability of the water, as a fog, to get deeply within the fire structure. In this manner it works to remove the three legs of the fire triangle~ heat, oxygen, and fuel. The research contained in this thesis dwells in three associated areas. These are: the general theory of water mist application relative to current practices~ the design and construction of a fire tunnel for experimental work; and the results obtained from experiments with fuel-rich fires in the simulated coal mine entry. The results of this research are most encouraging, not only for the more devastating fuelrich fires, but also for application from the onset of fire fighting activities in the coal mine environment. / Master of Science
179

Physical and chemical properties of coarse coal refuse from Southwest Virginia

Stewart, Barry R. 14 March 2009 (has links)
Coarse coal refuse is difficult to reclaim due to high potential acidity and coarse fragment content, low water holding capacity, low fertility, and other problems. Little is known about coal refuse properties, particularly as they relate to revegetation potential. This study was undertaken to determine the physical and chemical properties of composite samples from 27 coal waste piles of varying age. Selected physical and chemical properties varied widely across this sample set. The mean coarse fragment (>2mm) content of these materials was 60%. The average texture of the fine (<2mm) fraction was a sandy loam with 15% clay. The mean water retention difference, between 0.03 MPa and 1.5 MPa of soil moisture tension, on a whole sample basis was 0.08 g water/g refuse. The pH values varied from 8.3 to 3.0, and the older piles generally had lower pH values than the more recent piles. The saturated paste electrical conductivity (EC) was higher in the younger coal waste materials. Total elemental analysis revealed that Si, Al, Fe, and K were the most abundant elements in these materials. The mineralogy of three selected samples was found to be dominated by quartz in the sand and silt fraction and mica in the clay fraction. The physical factor most limiting to plant growth was found to be low water holding capacity. Low pH was found to be the chemical factor most limiting to plant survival. These findings indicate that some refuse piles may be suitable for direct seeding, but many will require heavy lime and/or organic treatments. / Master of Science
180

An economic evaluation of backfilling in Virginia's coal mines

Young-On, Harold 13 February 2009 (has links)
Backfilling is a technique used to place material in the voids created by underground mining. This technique has been used extensively abroad to reduce surface subsidence, fire hazards, and temperatures in underground workings. It can also help to eliminate environmental problems caused by coal waste dumps, improve coal recovery, and improve mine ventilation. However, backfilling is an additional operation in the coal mining cycle that can reduce productivity and increase production costs. This thesis identifies the backfilling methods applicable for coal mines in southwest Virginia. Following identification of variables that can affect the selection of a backfilling method, a multi-attribute decision analysis technique is developed. This technique is applied to a mine model which is representative for the mining conditions in southwest Virginia. An evaluation of the two most Suitable backfilling methods using coal refuse as fill material is then made and compared to the surface disposal of coal refuse. / Master of Science

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