The application of two-and-three-dimensional stress analysis techniques to the design of rock structures, with particular reference to underground pillars

An attempt was made in the course of this investigation, to introduce some modern laboratory and 'in-situ' techniques of Experimental Stress Analysis to mining configurations, and in particular, to the design of underground pillars. Chapters I and II are both introductory ones. In the former, the basic problems associated with the design of structures in rock are briefly outlined whereas in the latter, a detailed and up to date discussion is given, on the behaviour of underground pillars and their design considerations. In Chapters III and IV two modern and sophisticated photoelastic techniques are described, with particular reference to their application to mining. The Scattered Light technique of three-dimensional photo-elasticity, and the special polariscope on which this method can be executed, are described in Chapter III. In Chapter IV, an Image De-rotation technique has been specially adapted, to enable gravity loading simulation in 'real time'. The application of the Scattered Light technique to the field of Rock Mechanics, is given in Chapter V, where two cases of underground pillars are examined photo-elastically, in three dimensions. In order to examine the underground behaviour of pillars as well as establishing the degree of reliance of the photoelastic results, two 'in-situ' investigations were carried out, and are described in detail in Chapter VI. Finally, the important problem of developing improved methods of 'in-situ' measurements was not ignored. The design and laboratory testing of two instruments capable of triaxial measurements at a point 'in-situ', from a single borehole, is discussed in Chapter VII.An attempt was made in the course of this investigation, to introduce some modern laboratory and 'in-situ' techniques of Experimental Stress Analysis to mining configurations, and in particular, to the design of underground pillars. Chapters I and II are both introductory ones. In the former, the basic problems associated with the design of structures in rock are briefly outlined whereas in the latter, a detailed and up to date discussion is given, on the behaviour of underground pillars and their design considerations. In Chapters III and IV two modern and sophisticated photoelastic techniques are described, with particular reference to their application to mining. The Scattered Light technique of three-dimensional photo-elasticity, and the special polariscope on which this method can be executed, are described in Chapter III. In Chapter IV, an Image De-rotation technique has been specially adapted, to enable gravity loading simulation in 'real time'. The application of the Scattered Light technique to the field of Rock Mechanics, is given in Chapter V, where two cases of underground pillars are examined photo-elastically, in three dimensions. In order to examine the underground behaviour of pillars as well as establishing the degree of reliance of the photoelastic results, two 'in-situ' investigations were carried out, and are described in detail in Chapter VI. Finally, the important problem of developing improved methods of 'in-situ' measurements was not ignored. The design and laboratory testing of two instruments capable of triaxial measurements at a point 'in-situ', from a single borehole, is discussed in Chapter VII

Ground Movement Characteristics above Mined Panels in Appalachia-an Empirical Approach

The growing recognition of mining subsidence and its effects has provoked numerous investigations into the modeling and prediction of this phenomenon. Through an analysis of case histories and examination of the various modeling techniques, it has become apparent that empirical studies currently represent the most realistic approach to this problem. However, the collection, analysis and interpretation of subsidence and strain data acquired from case studies presents substantial difficulties, due to varying monitoring techniques and methods of analysis. In this paper it is suggested that a prescribed monitoring program could eliminate these problems and ensure quality data by standardizing the measurement process. Such an effort may also increase the number of case studies available for analysis, allowing more intense investigations of subsidence prediction methods. Finally, some basic subsidence relationships developed from the established subsidence data bank on longwall and room and pillar mines in Appalachia are discussed in detail. These relationships may provide important information on the characteristics of ground movements above mined areas and thus greatly facilitate engineering design under these conditions

Europe as a multilevel federation

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Underground Coal Gasification and Potential for Greenhouse Gas Emissions Reduction

Underground coal gasification (UCG) is an advancing technology that is receiving considerable global attention as an economic and environmentally friendly alternative for exploitation of coal deposits. This technology has the potential to decrease greenhouse gas emissions during the development of coal deposits. The environmental benefits of UCG that promote reduction in greenhouse gas emissions include elimination of conventional mining, coal washing and fines disposal, coal stockpiling and coal transportation activities. Additional benefits include; a smaller surface area requirement with minimal surface disruption; removal of CO₂ from the syngas at significantly reduced cost as compared to carbon capture and transport from a power plant; and the potential to reduce CH 4 emissions, a potent greenhouse gas. UCG utilizes coalbed methane irrespective of its economic value during the burning process and increases energy efficiency. The CH₄ in the product gas is consumed completely during power and/or electricity generation, thus reducing overall methane emissions to the atmosphere. This paper compares greenhouse gas emissions from conventional mining methods to UCG for the exploitation of a coal reserve. The findings indicate that UCG reduces greenhouse gas emissions significantly as compared to other competitive coal exploiting technologies. This research may help in the selection of a suitable method to develop coal deposits when the reduction of greenhouse gases is an essential part of planning. Copyright 2012, Carbon Management Technology Conference

Proceedings of Twenty-Seventh Annual Institute on Mining Health, Safety and Research

This Proceedings contains the presentations made during the program of the Twenty-Seventh Annual Institute on Mining Health, Safety and Research held at Virginia Polytechnic Institute and State University, Blacksburg, Virginia, on August 26-28, 1996. The Twenty-Seventh Annual Institute on Mining, Health, Safety and Research was the latest in a series of conferences held at Virginia Polytechnic Institute and State University, cosponsored by the Mine Safety and Health Administration, United States Department of Labor, and the Pittsburgh Research Center, United States Department of Energy (formerly part of the Bureau of Mines, U. S. Department of Interior). The Institute provides an information forum for mine operators, managers, superintendents, safety directors, engineers, inspectors, researchers, teachers, state agency officials, and others with a responsible interest in the important field of mining health, safety and research. In particular, the Institute is designed to help mine operating personnel gain a broader knowledge and understanding of the various aspects of mining health and safety, and to present them with methods of control and solutions developed through research. Selected papers have been processed separately for inclusion in the Energy Science and Technology database

Simulation and Modeling of Pillar Stability and Analysis of Safety Factor

Simulation and modeling is powerful tool to analyze real time data and can be used to analyze different scenarios using appropriate software that may reduce need of infield data collection process and can predict reasonably accurate results. In this paper the real time data of a mine is used to simulate and model the stresses on the pillars and evaluate the pillar strength and safety factor. The material properties assigned to the model are obtained by testing the representative samples taken from the selected locations of the mine. The mine under investigation has 50 ft wide pillars and 50 ft wide rooms under an average overburden of 650 feet. The effect of reduced pillar dimensions and increased roof span on overall stability of mine and extraction ratio is analyzed using LaModel[1] software. The predicted results of the reducing pillar size are analyzed to compares the current mining practices with the optimized room and pillar size to get better extraction ratio without comprising the safety

A Life Cycle Comparison of Greenhouse Emissions for Power Generation from Coal Mining and Underground Coal Gasification

Underground coal gasification (UCG) is an advancing technology that is receiving considerable global attention as an economic and environmentally friendly alternative for exploitation of coal deposits. UCG has the potential to decrease greenhouse gas emissions (GHG) during the development and utilization of coal resources. In this paper, the life cycle of UCG from in situ coal gasification to utilization for electricity generation is analyzed and compared with coal extraction through conventional coal mining and utilization in power plants. Four life cycle assessment models have been developed and analyzed to compare (greenhouse gas) GHG emissions of coal mining, coal gasification and power generation through conventional pulverized coal fired power plants (PCC), supercritical coal fired (SCPC) power plants, integrated gasification combined cycle plants for coal (Coal-IGCC), and combined cycle gas turbine plants for UCG (UCG-CCGT). The analysis shows that UCG is comparable to these latest technologies and in fact, the GHG emissions from UCG are about 28 % less than the conventional PCC plant. When combined with the economic superiority, UCG has a clear advantage over competing technologies. The comparison also shows that there is considerable reduction in the GHG emissions with the development of technology and improvements in generation efficiencies. © 2014 Springer Science+Business Media Dordrecht