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1
Misich, Ian J. "Subsidence prediction and mine design for underground coal mining in the Collie Basin." Thesis, Curtin University, 1997. http://hdl.handle.net/20.500.11937/88.
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The subsidence characteristics of the Collie Basin sediments have been investigated to provide site specific design criteria for the Wongawilli method of coal extraction. As historical coal extraction (bord and pillar) methods did not generally give rise to large scale subsidence, there were very few details on mining subsidence in the Collie Basin available to base any design methodology on. Consequently, the investigation was conducted on a Green fields basis. Firstly, the mechanisms involved in the development of mining subsidence needed to be investigated and identified. It was then necessary to determine the effects that mining subsidence would have on mine and ground mass (specifically aquitards) structures and surface features. Once these two areas of work were completed, design criteria were formulated to manage the effects of mining subsidence by controlling the critical mechanisms of subsidence development.The results from this study have greatly enhanced the level of understanding of the subsidence mechanisms involved, and allowed for the development of predictive models which can be used for the design of coal extraction by the panel/pillar mining method in the Collie Basin. Mine planning engineers can now use this design information to derive the most cost effective methods for the extraction of coal within the Collie Basin.
2
Haciosmanoglu, Esenay Meryem. "Development Of A Subsidence Model For Cayirhan Coal Mine." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605481/index.pdf.
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In this study, subsidence analyses were carried out for panels B14, B12, B10, B02, C12, C10, C08 of Ç<br>ayirhan Lignite Mine using in-situ subsidence measurements.
Using the measurements from stations, installed both parallel and perpendicular to panel-advance direction, subsidence profiles were plotted as a function of time and distance from panel center. Horizontal displacement and strain curves were also plotted and compared with subsidence profiles.
There are various methods used for subsidence prediction. In this study however, a subsidence model was developed based on empirical model obtained from nonlinear regression analysis. During the analyses SPSS (V.10.0) software was used and the unknown parameters associated with subsidence function were determined for the stations above B14 panel. Since it was too complicated to take all the affecting factors into consideration, only the parameters which could be estimated by statistical evaluation were taken into account during analyses.
One significant contribution of this study to subsidence subject was the comparison of the subsidence values measured during this investigation with the values predicted by some other empirical methods.
In this study, the structural damages to the pylons installed on ground surface above retreating longwall panels were also investigated by the use of previous studies. Slope as well as horizontal strain changes caused by ground movements
due to underground mining were determined.
Last but not least, it should be stated another significant contribution of this study to engineering was the collection of a significant database obtained from field measurements.
3
Misich, Ian J. "Subsidence prediction and mine design for underground coal mining in the Collie Basin." Curtin University of Technology, School of Civil Engineering, 1997. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=12359.
Full textAbstract:
The subsidence characteristics of the Collie Basin sediments have been investigated to provide site specific design criteria for the Wongawilli method of coal extraction. As historical coal extraction (bord and pillar) methods did not generally give rise to large scale subsidence, there were very few details on mining subsidence in the Collie Basin available to base any design methodology on. Consequently, the investigation was conducted on a Green fields basis. Firstly, the mechanisms involved in the development of mining subsidence needed to be investigated and identified. It was then necessary to determine the effects that mining subsidence would have on mine and ground mass (specifically aquitards) structures and surface features. Once these two areas of work were completed, design criteria were formulated to manage the effects of mining subsidence by controlling the critical mechanisms of subsidence development.The results from this study have greatly enhanced the level of understanding of the subsidence mechanisms involved, and allowed for the development of predictive models which can be used for the design of coal extraction by the panel/pillar mining method in the Collie Basin. Mine planning engineers can now use this design information to derive the most cost effective methods for the extraction of coal within the Collie Basin.
4
Platt, Marcor Gibbons. "Visualizing and Modeling Mining-Induced Surface Subsidence." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/2223.
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Ground subsidence due to underground coal mining is a complex, narrowly-understood phenomenon. Due to the complicated physical processes involved and the lack of a complete knowledge of the characteristics of overlying strata, the reliability of current prediction techniques varies widely. Furthermore, the accuracy of any given prediction technique is largely dependent upon the accuracy of field measurements and surveys which provide input data for the technique. A valuable resource available for predicting and modeling subsidence is aerial survey technology. This technology produces yearly datasets with a high density of survey points. The following study introduces a method wherein these survey points are converted into elevation plots and subsidence plots using GIS. This study also presents a method, titled the Type-Xi Integration method (TXI method), which improves upon a previous subsidence prediction technique. This method differs from the previous technique in that it incorporates accurate surface topography and considers irregular mine geometry, as well as seam thickness and overburden variations in its predictions. The TXI method also involves comparing predicted subsidence directly to measured subsidence from subsidence plots. In summary, this study illustrates a method of combining data from aerial survey points and mine geometry with subsidence models in order to improve the accuracy of the models.
5
Kolli, Shiva Prasad B. "Analyses of coal extraction and spoil handling techniques in mountainous areas." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1971.
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Thesis (M.S.)--West Virginia University, 2001.<br>Title from document title page. Document formatted into pages; contains x, 64 p. : ill. (some col.), maps. Includes abstract. Includes bibliographical references (p. 63-64).
6
Roth, Richard A. "Longwall mining, subsidence, and protection of water resources in Virginia." Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/50086.
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In the coalfields of Southwest Virginia, Iongwall technology accounts for an increasing proportion of underground coal mine production. lt is a highly productive, capital intensive method that provides a degree of mine safety greater than conventional 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 redress in the courts. At the same time, the U.S. Surface Mine Control and Reclamation Act (SMCRA) provides a framework for regulation of the environmental effects of coal mining, including hydrologic effects. The Department of Mines, Minerals, and Energy, Division of Mined Land Reclamation (DMLR) is responsible for implementation of Virginia’s primacy program under SMCRA.
This research has assessed the potential of Iongwall mining to damage the groundwater and surface water resources In Southwest Virginia; and examined whether existing laws and regulations, as implemented, provide an adequate and appropriate level of protection to both water property rights and the environment. Methods included review of published and ongoing literature on effects of underground coal mining on hydrologic systems and methods of mitigation; review of mining permits and complaint investigations on file at DMLR; review of court case decisions involving mining effects on groundwater and surface water; review of regulatory documents from other states active in Iongwall mining and the Federal Office of Surface Mining (OSM); and interviews with coal company personnel, DMLR and OSM officials, researchers, and regulatory officials in other states.
Review of both DMLR complaint investigations and published reports of numerous hydrologic investigations indicate that longwall mining is likely to alter the hydrologic regime in the vicinity of the mine. The knowledge base for regulation of hydrologic impacts has been inadequate but is being improved in Virginia. Both DMLR and some coal companies recognize the need for more and better data, and are taking steps to develop the requisite data and models. Regulatory personnel in Ohio, Pennsylvania, West Virginia, and Kentucky have expressed recognition of similar data deficiencies in their states. At least one state, Ohio, has dealt with the problem of water rights by enacting legislation that assigns liability for replacing damaged water supplies to the mining companies. West Virginia, through its regulatory program, also requires water replacement. Recommendations are offered that have as their main objective the reduction of uncertainty about the effects of longwall mining and about compensation of surface owners for damage to water supplies.<br>Master of Urban and Regional Planning<br>incomplete_metadata
7
Save, Neelambari R. "Ground penetrating radar technique to locate coal mining related features: case studies in Texas." Texas A&M University, 2004. http://hdl.handle.net/1969.1/3204.
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The goal of this research project is to identify the efficacy of the ground
penetrating radar (GPR) technique in locating underground coal mine related subsidence
features at Malakoff and Bastrop, Texas. The work at Malakoff has been done in
collaboration with the Railroad Commission of Texas (RRC). RRC has been carrying
out reclamation of abandoned underground coal mines at Malakoff since the early
1990Âs. The history of the specific mining operations (at Malakoff and Bastrop) that
took place in the early 1900Âs has been difficult to ascertain; therefore, the use of a
geophysical techniques like ground penetrating radar to identify hidden voids and
potential subsidence features is vital for future reclamation process. Some of the
underground mine workings at the field site have collapsed over time affecting the
topography by creating sinkholes. GPR data, employing 25 MHz, 50 MHz and 100
MHz frequency antennae, have been collected in common offset patterns and azimuthal
pattern. GPR data indicate the mine tunnels possibly connecting existing sinkholes by
radargram hyperbolae that correspond with mine openings observed visually or during
reclamation. This study also denotes the importance of understanding the variable
physical properties of the stratigraphy, which could lead to false alarms by
misinterpretation of the radar signals. Natural and man-made above-ground structures
cause obstructions in data collection, and hence an optimal design is required for each
survey. RRC successfully ground-truthed the data during its reclamation process. In
turn, the acquired geophysical data helped to guide the reclamation. At Bastrop, GPR
data along with historical documentation led to the conclusion that coal mining did exist
in this region but is not a major concern to the immediate stability and safety of the field
site. It can be concluded from both the studies that the GPR technique identifies
anomalous shafts/tunnels possibly connecting potential failure.
8
Keilich, Walter. "Numerical modelling of mining subsidence, upsidence and valley closure using UDEC." School of Civil, Mining & Environmental Engineering - Faculty of Engineering, 2009. http://ro.uow.edu.au/theses/862.
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Ground subsidence due to mining has been the subject of intensive research for several decades, and it remains to be an important topic confronting the mining industry today. In the Southern Coalfield of New South Wales, Australia, there is particular concern about subsidence impacts on incised river valleys – valley closure, upsidence, and the resulting localised loss of surface water under low flow conditions. Most of the reported cases have occurred when the river valley is directly undermined. More importantly, there are a number of cases where closure and upsidence have been reported above unmined coal. These latter events are especially significant as they influence decisions regarding stand-off distances and hence mine layouts and reserve recovery.The deformation of a valley indicates the onset of locally compressive stress conditions concentrated at the base of the valley. Compressive conditions are anticipated when the surface deforms in a sagging mode, for example directly above the longwall extraction; but they are not expected when the surface deforms in a hogging mode at the edge of the extraction as that area is typically in tension. To date, explanations for valley closure under the hogging mode have considered undefined compressive stress redistributions in the horizontal plane, or lateral block movements and displacement along discontinuities generated in the sagging mode. This research is investigating the possibilities of the block movement model and its role in generating compressive stresses at the base of valleys, in the tensile portion of the subsidence profile. The numerical modelling in this research project has demonstrated that the block movement proposal is feasible provided that the curvatures developed are sufficient to allow lateral block movement. Valley closure and the onset of valley base yield are able to be quantified with the possibility of using analytical solutions. To achieve this, a methodology of subsidence prediction using the Distinct Element code UDEC has been developed as an alternative for subsidence modelling and prediction for isolated longwall panels. The numerical models have been validated by comparison with empirical results, observed caving behaviour and analytical solutions, all of which are in good agreement. The techniques developed in the subsidence prediction UDEC models have then been used to develop the conceptual block movement model. The outcomes of this research have vast implications. Firstly, it is shown that valley closure and upsidence is primarily a function of ground curvature. Since the magnitude of curvature is directly related to the magnitude of vertical subsidence there is an opportunity to consider changes in the mine layout as a strategy to reduce valley closure. Secondly, with further research there is the possibility that mining companies can assess potential damage to river valleys based on how close longwall panels approach the river valley in question. This has the added advantage of optimising the required stand off distances to river valley and increasing coal recovery.
9
Bode-Jimenez, Gabriel. "ASSESSMENT OF POTENTIAL IMPACTS TO SUBSURFACE BODIES OF WATER DUE TO UNDERGROUND COAL MINING." UKnowledge, 2017. http://uknowledge.uky.edu/mng_etds/35.
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Underground coal mining operations induce ground movements, which may impact overlying hydrogeologic systems. Potential impacts mainly include changes in the hydraulic conductivity of overlying strata, decreasing of the hydraulic head and changes in water flow. The present research quantifies potential hydrogeologic impacts caused by underground mining through modeling of pre- and post-mining hydrogeologic systems.
Three-dimensional conceptual hydrogeologic models were constructed with the Processing Modflow for Windows software package (PMWiN). The models are based on an actual case study, but were simplified in terms of geometry and material properties. Water flow was simulated under changing hydrogeologic properties. A number of scenarios were investigated including models with horizontal or inclined topography, featuring an aquifer overlying two longwall panels. The hydrogeologic properties of the models were estimated based on empirical relationships between the post-mining hydraulic conductivity and strain in the overburden. The strain regime in the overburden was estimated using the Surface Deformation Prediction System (SDPS) package, which allows calculation of surface deformations due to underground coal mining.
The research focuses on changes in hydraulic heads; results indicate that hydraulic heads may decrease over undermined areas and may rebound as mining ceases. Water infiltration may occur from higher located overburden formations to lower formations due to mining induced changes in hydrogeologic properties.
10
Md, Azmi Ahmad Zharif. "CFD ANALYSIS OF AIRFLOW PATTERNS IN HIGH MINING AREAS OF ROOM-AND-PILLAR COAL MINING." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1574.
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This thesis studies airflow patterns in the face area of a typical room-and-pillar mining area, using Computational Fluid Dynamics (CFD) modeling. This research is designed to develop a scientific understanding of airflow distribution in room-and-pillar mining areas that is fundamental to developing engineering controls. The overall goal of the study is to develop improved engineering controls to minimize dust exposure of mine workers in the face area. Dust exposure can be a health hazard in underground coal mining industry based on historical data of coal workers' pneumoconiosis among underground mine workers. Current regulatory dust exposure standards of 1.5 mg/m3, averaged over an 8-hour period, have been recently revised with approval of new MSHA standards in April of 2014. Mining companies are currently seeking new technologies in order to comply with the new dust standards. Since mining geometries are complex and do not lend themselves to closed-form analytical solutions, CFD numerical modeling approach was used to develop an understanding of airflow distribution in the face areas. Since previous studies had focused on some cuts in mining heights of less than 2.4 m (8-ft), this study was performed for high mining areas of 4.2 m (14-ft). Such mining heights are very common in longwall mine development areas, particularly in the State of Illinois. The primary goal was to identify major differences in airflow between the two mining heights and how they affect development of engineering controls for minimizing dust exposure. Simulations were done using ANSYS software such as DesignModeler for modeling and meshing and FLUENT for calculations. Recirculation (RC) and low air velocity (LAV) zones were located for straight deep cut, straight deepest cut, cross-cut right, cross-cut right mine through, left turn cross-cut, and left turn cross-cut mine through for low mining height (LMH) and high mining height (HMH) with varying air quantity at the end of the line curtain (ELC). Air at the ELC was adjusted to achieve a ratio of 0.85, 1.00 and 1.15 over the wet scrubber fan (WSF) discharge capacity. Results show that the air velocity in HMH case is much lower than for the LMH. In addition, the location of RC and LAV zones differ based on mining height and air quantity at the ELC. Furthermore, lower air quantity at the ELC causes the air exhausted by the WSF to recirculate back to the face area in order to satisfy the WSF requirement. Recommendations to deal with these differences are formulated.
11
Nejad, Mehdi Afsari. "Numerical modelling of inclined seams." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263425.
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Yu, Myong-Hwan. "Geohazards associated with rising groundwater in urban areas affected by former coal mining." Thesis, University of Birmingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433423.
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Hescock, Joshua. "CALCULATION OF THE EDGE EFFECT OFFSET FOR HIGH EXTRACTION COAL PANELS." UKnowledge, 2017. http://uknowledge.uky.edu/mng_etds/36.
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The Surface Deformation Prediction System (SDPS) program has been developed as an engineering tool for the prediction of subsidence deformation indices through the implementation of an influence function. SDPS provides reliable predictions of mining induced surface displacements, strains, and tilt for varying surface topography. One of the key aspects in obtaining reliable ground deformation prediction is the determination of the edge effect offset. The value assigned to the edge effect corresponds to a virtual offsetting of boundary lines delineating the extracted panel to allow for roof cantilevering over the mined out area.
The objective of this thesis is to describe the methods implemented in updating the edge effect offset algorithm within SDPS. Using known geometric equations, the newly developed algorithm provides a more robust calculation of the offset boundary line of the extracted panel for simplistic and complex mining geometries. Assuming that an extracted panel is represented by a closed polyline, the new edge offset algorithm calculates a polyline offset into the extracted panel by the user defined edge effect offset distance. Surface deformations are then calculated using this adjusted panel geometry. The MATLAB® program was utilized for development and testing of the new edge effect offset feature.
14
Kobayashi, Kenichiro. "Optimization methods for multiphase systems in the subsurface application to methane migration in coal mining areas." Stuttgart Inst. für Wasserbau, 2004. http://deposit.d-nb.de/cgi-bin/dokserv?idn=975382160.
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Khan, Muhammad Abbas. "Detection of collapses and communicating with inaccessible areas in underground coal mines using WSN." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1782.
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Wireless sensor networks (WSN) are used in underground mines to monitor concentration of gases, temperature, and humidity. A WSN deployed in underground mines can also be used for localisation of miners and for detecting collapses. Underground coal mines consist of long and narrow tunnels, several hundred metres beneath the surface of earth. These tunnels can be several kilometres long, with the width and height of these tunnels being no more than a few metres. A WSN in underground coal mine is an example of a chain type wireless sensor network (CWSN). CWSNs are special types of WSNs in which sensor nodes are placed along an elongated geographical area with the nodes forming a chain topology. In CWSNs, their shape dictates network design. Unlike other large scale WSN, there is only one path for data transfer in CWSNs. Hence the probability of network getting broken in disjoint sections, due to node failures, is much higher in CWSNs compared to other large scale WSNs. Disjoint sections are two sections of the same network which are out of the communication range of each other. When the network is broken into two or more disjoint sections, the sink node loses connectivity with parts of the network and hence some areas are left unmonitored despite having functional sensor nodes.
In the first contribution chapter of this thesis, we design a distributed connectivity restoration algorithm for generic chain-type wireless sensor networks. We usemovable relay nodes to restore connectivity in the network. Our algorithm strivesto move a minimum number of relay nodes while only requiring local knowledge ofthe network. In the second contribution chapter, we consider the scenario of collapses occurring in underground coal mines. We design an algorithm for detecting collapses in chapter four. A collapse may leave parts of the mine inaccessible and unmonitored. A collapse will also break WSN into two or more disjoint sections which are physically separated by the collapse consisting of soil and rock. We investigate the propagation characteristics of EM waves through soil and rock. We determine the factors on which communication range of EM waves through soil depends on. We propose special movable relay nodes which use low frequency and high power transmitters to communicate through a collapsed area of the mine, restoring connectivity in the WSN. We design an algorithm to restore connectivity through collapsed areas of the underground mine tunnels using these special movable relay nodes. Communicating with inaccessible area of the mine will help locate miners which may be trapped in that section and will enable the network to monitor the inaccessible area of the mine.
16
Contreras-Valdivia, Germán E. "Subsidence and Ground Movement Monitoring Instrumentations for US R 33 Nelsonville Bypass, Athens County, Ohio." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1385132355.
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Alam, Mohammad Masroor. "An integrated approach to dust control in coal mining face areas of a continuous miner and its computational fluid dynamics modeling /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1203573831&sid=2&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Claassens, Sarina. "Measuring rehabilitation success of coal mining disturbed areas : a spatial and temporal investigation into the use of soil microbial properties as assessment criteria / Sarina Claassens." Thesis, North-West University, 2007. http://hdl.handle.net/10394/1295.
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Kobayashi, Kenichiro [Verfasser]. "Optimization methods for multiphase systems in the subsurface : application to methane migration in coal mining areas / Institut für Wasserbau der Universität Stuttgart. Vorgelegt von Kenichiro Kobayashi." Stuttgart : Inst. für Wasserbau, 2005. http://d-nb.info/975382160/34.
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Zimmermann, Karsten. "Prognose und bergschadenkundliche Analyse dynamischer Bodenbewegungen durch oberflächennahen Steinkohlenbergbau in den USA." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2011. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-65009.
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Der untertägige Abbau von Steinkohle führt zu Bewegungen des überlagernden Gebirges und der Tagesoberfläche. Eine Bewegungsprognose ist im Hinblick auf entstehende Bergschäden weltweit von großer Bedeutung. In dieser Arbeit wird untersucht, ob eine Prognose von Bodenbewegungen im amerikanischen Steinkohlenbergbau mit einem in Europa bewährten Verfahren, einem dynamischen stochastischen Senkungsmodell, möglich ist. Dazu wurde eine Literaturstudie über den bisherigen Kenntnisstand in den USA durchgeführt, abbaubegleitende Bodenbewegungsmessungen aus dem Steinkohlengebiet der Appalachen ausgewertet und durch Modellrechnungen nachgebildet. Es wurde darüber hinaus untersucht, welchen Einfluss die spezifischen Abbaubedingungen und die räumliche und zeitliche Abbauführung auf die Größe und Dynamik von Bodenbewegungen haben. Die theoretischen und praktischen Untersuchungen zeigen einen deutlichen Know-how Vorsprung des europäischen Bergbaus in den Bereichen der Senkungsmodellierung und Bewertung abbauinduzierter Bodenbewegungen und belegen die Anwendbarkeit des Senkungsmodells. Es wurden wichtige Erkenntnisse gewonnen, die Möglichkeiten und Grenzen einer Optimierung des Abbauzuschnitts und der zeitlichen Abbauführung im Sinne einer bergschadensmindernden Abbauplanung aufzeigen. Die Arbeit trägt zur Verbesserung der bergmännischen und markscheiderischen Abbauplanung im Steinkohlenbergbau bei.
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Kumar, Sanjay. "Analysis of Subsidence and Stability of Pillars in A Coal Mine." Thesis, 2015. http://ethesis.nitrkl.ac.in/7368/1/110.pdf.
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The significance of mining will be certainly immense to human development. Truly, as one of the biggest of human endeavours, Mining and its improvements relate nearly with social progress. One of underground mining methods is the Bord and Pillar Method of Mining and this method is one of the oldest Mining Methods. By the help of Bord and Pillar Mining, extraction will be high. The key to successful Bord and Pillar Mining is selecting the optimum pillar size and stability of the pillar. If the pillars are too small the mine will collapse. If the pillars are too large then significant quantities of valuable material will be left behind reducing the profitability of the mine. The issues relating to the stability of pillars and Subsidence from it will be a major concern now-a-days. The most critical parameter before outlining and stability of pillars will be the Safety component. The primary objective of this project is to increase the extraction proportion with the help of stability of created pillars and subsidence control and Based on laboratory testing of coal samples, empirical and numerical modelling studies related to the stability of the pillar and analysis of observation data on subsidence profiles for underground coal mine, the following conclusions are done. Field observations at Kumda underground mine indicated stability of the pillars without any perceptible side spilling and crushing. Uniaxial compressive strength, triaxial testing of coal samples indicated UCS, cohesion(C) and internal friction angle(∅) of 27.9 MPa, 1.85 MPa and 300 respectively. Empirical and numerical modelling using two dimensional continuum analyses indicated the maximum stress of 5 MPa over the pillar and safety factor exceeding 2 confirming to the qualitative observation of stability of the pillar. Maximum subsidence at 1.58 m was observed over the over the extracted panels with a subsidence factor of 0.63 for the depillaring panels with the width and depth of 64 m-14 m, 30 m-45.5 m respectively The significance of mining will be certainly immense to human development. Truly, as one of the biggest of human endeavours, Mining and its improvements relate nearly with social progress. One of underground mining methods is the Bord and Pillar Method of Mining and this method is one of the oldest Mining Methods. By the help of Bord and Pillar Mining, extraction will be high. The key to successful Bord and Pillar Mining is selecting the optimum pillar size and stability of the pillar. If the pillars are too small the mine will collapse. If the pillars are too large then significant quantities of valuable material will be left behind reducing the profitability of the mine. The issues relating to the stability of pillars and Subsidence from it will be a major concern now-a-days. The most critical parameter before outlining and stability of pillars will be the Safety component. The primary objective of this project is to increase the extraction proportion with the help of stability of created pillars and subsidence control and Based on laboratory testing of coal samples, empirical and numerical modelling studies related to the stability of the pillar and analysis of observation data on subsidence profiles for underground coal mine, the following conclusions are done. Field observations at Kumda underground mine indicated stability of the pillars without any perceptible side spilling and crushing. Uniaxial compressive strength, triaxial testing of coal samples indicated UCS, cohesion(C) and internal friction angle(∅) of 27.9 MPa, 1.85 MPa and 300 respectively. Empirical and numerical modelling using two dimensional continuum analyses indicated the maximum stress of 5 MPa over the pillar and safety factor exceeding 2 confirming to the qualitative observation of stability of the pillar. Maximum subsidence at 1.58 m was observed over the over the extracted panels with a subsidence factor of 0.63 for the depillaring panels with the width and depth of 64 m-14 m, 30 m-45.5 m respectively
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Tribe, Norm L., and L. John Tribe. "A successful method of reclaiming subsidence in abandoned mining areas." 1999. http://hdl.handle.net/2429/9623.
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Old mine openings present hazards to the public and liabilities to the property owners. Many makeshift attempts have been devised to solve the problems of old mine openings and mine subsidence, but few have been successful.
This document will describe a method of plugging mine shafts, ventilation raises and mine cave subsidence which has been designed, tested and found to be successful, meets environmental requirements and has not failed in over 150 reclamation sites.
Engineering design parameters were first applied by the writers to the plugging of mine openings in 1992. The design was inspired by the expandable thermos bottle cork which expands into the fragile throat of the vacuum bottle and seals it off. The concept was adapted to the mine openings
with old mine tires as the cork. The compound polymer-steel toroid structural unit (loader tire) is designed to compensate for poor anchor points, loose rock, a tensional component in the stresses and when compressed and allowed to expand into the cavity, applies considerable pressure on the
sides of the cavity, stabilizing the opening. This is a dynamic structural design component, capable of moving with the rock as the strain is taken up and the latent stresses in the rock are relieved. Once the opening is stabilized using the toroid plug, a three step, matte, mesh and cloth geotechnical solution can be applied and finished with backfill, topsoil and seeding to complete the reclamation.
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Suchowerska, Iwanec Anastasia M. "The geomechanics of single-seam and multi-seam longwall coal mining." Thesis, 2014. http://hdl.handle.net/1959.13/1045349.
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Research Doctorate - Doctor of Philosophy (PhD)<br>In coal mining, the most favourable and most easily won coal reserves are depleted first, typically from within a single coal seam. A recent trend in Australia and elsewhere in the world is to attempt to recover coal from multiple seams within a single site, a practice known as multi-seam mining. With longwall mining becoming one of the safest and most economical means of underground extraction of coal in Australia, we are likely to see an increase in the number of multi-seam longwall mining operations. Evidence thus far has indicated that the geomechanics of multi-seam longwall mining differs from that of single-seam longwall mining, especially with respect to variations in mine stability and subsidence. The overarching aim of this Thesis is to critically compare predicted stresses and deformations for single-seam and multi-seam longwall mines based on commonly used constitutive laws and continuum-based modelling assumptions. The main approach used to predict stresses and deformations is the displacement finite element method. Finite element limit analyses of roof collapse are also considered. In all cases, twodimensional (plane strain) conditions were assumed, and focus is on relatively wide longwall panels at shallow depth, known as supercritical longwall panels. Key objectives are to predict stress redistributions in multi-seam longwall mines, roof collapse in underground openings, and subsidence profiles above single-seam and multi-seam longwall mines. The changes in the vertical and horizontal stress distribution due to the extraction of a series of parallel longwall panels were predicted using isotropic and anisotropic linear elastic constitutive laws to represent the coal measure strata. The key finding from the study of vertical stress redistribution is that the abutment angle, the overburden depth, the pillar width and the anisotropic behaviour most influence the change in the in situ vertical stress in the lower seam. The redistribution of horizontal stress originally transmitted through the overburden generates smaller changes to the in situ stresses in the rock strata below the first mined seam than is predicted for the vertical stress. Transversely isotropic material causes the vertical stresses imposed onto the chain pillars to be transferred deeper into the underlying strata. The implications of the findings are that the predicted rapid changes in vertical stress with horizontal distance in transverse isotropic strata behaviour are likely to be reflected in more sudden changes in rock mass response which pose a safety risk. The differences occurring in predictions of roof collapse in underground rectangular cavities using the Hoek-Brown and Mohr-Coulomb failure criteria were evaluated. The predicted shape of the failure surface is shown to be governed by the friction angle of the rock mass. The friction angle also governs the so-called critical width, which corresponds to the boundary between subcritical and supercritical failure of the overburden. The predictions of the critical width matches best field observations in the New South Wales coalfields when the linear Mohr-Coulomb failure criterion is used with a friction angle of approximately 30 degrees. The prediction of the critical width when using the Hoek-Brown failure criterion overestimates the value observed in the field. This is because the Hoek-Brown failure criterion corresponds to effectively high friction angles in the range of tensile and very low confining stresses encountered in the strata above underground openings. Stability charts for rectangular cavities using the Hoek-Brown failure criterion and two forms of the Mohr-Coulomb failure criterion are presented to enable designers of underground openings to predict rapidly the safe widths of underground cavities. Predictions of vertical subsidence profiles above single-seam and multi-seam longwall panels are compared using various constitutive laws to represent the coal measure strata and goaf. A key finding is that the best agreement between the numerical predictions and the field observations, for both the single-seam and multi-seam supercritical longwall cases, is when the coal measure strata is represented as an elastic material with closely spaced frictionless interfaces representing bedding planes. Representing the coal measure strata as a bedded material also allows for the vertical stresses to return to the level of the original overburden stress in the caved goaf material within the first seam, prior to extraction of the second seam. The results show that more sophisticated and numerically taxing constitutive laws do not necessarily lead to more accurate results when compared to field measurements. A case study based on a multi-seam mine in the Hunter Valley assists in validating the conclusions made in the comparative study. The findings presented in this Thesis will enable engineers to design economically viable multi-seam longwall mines, while still meeting legislative needs in terms of the environment and safety of personnel.
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Ntui, Charles Mboh-Arrey. "Hazard assessment and disaster preparedness towards sustainable development in Mpumalanga (South Africa) coal-mining areas." Thesis, 2013. http://hdl.handle.net/10210/8445.
Full textAbstract:
PhD (Environmental Management)<br>Mining and mining-related activities remain the world’s most intensive, primary industrial activity undertaken with severe environmental impact. Coal mining falls within these primary undertakings, while coal burning for energy use further adds to environmental degradation. Coal burning is by far the least expensive and thus the most affordable means of energy supply to the South Africa low-income communities. It is likely that this status quo will continue indefinitely. The use of coal as an energy source in South African communities has been inherited with its resultant environmental (physical), social and economic implications. The physical implications are the actual hazards associated with coal during and after mining activities. “Physical hazards” include processes generating coal dust, coal ash and gaseous emissions, and hazards that manifest themselves from the existence of coal mining at a particular site, such as spontaneous combustion, surface instability and acid mine-water drainage. “Social hazards” are mostly the social and economic effects that are related to health. Social hazards associated with coal mining, coal processing and coal usage include dilution of cultural values, ethics, norms and the growth of informal sectors, for example, settlements and trade. Some of these hazards are immediate, while others are long-term and cumulative. Emphasis was placed on the cumulative effects of mining activities and the need to address issues relating to communities that live close to mining operations. This process of addressing community concerns is known as “creating a sustainable mining community”. South Africa hosted the 2002 World Summit on Sustainable Development and is a signatory of the working plan of action known as the Johannesburg Plan of Implementation. Therefore, one would expect to see that mining communities in South Africa are acting on and benefiting from this plan of action. The aim of this research is to assess the effectiveness of the 2002 World Summit on Sustainable Development and the Johannesburg Plan of Implementation in promoting sustainable mining and sustainable communities through changes in practices, perceptions and community participation in decision making. The research, undertaken during February to June 2007, examines the role of stakeholders and local authorities in basic environmental decisions. Environmental decisions examined were the provision of education and information to the community, uplifting community welfare through corporate social investment and corporate social responsibility. The surrounding communities of eMalahleni (formerly Witbank) in the Mpumalanga (Highveld) coal-mining region – were identified as a suitable area for this case study. Social research tools, comprising multiple-choice and open-ended questions administered to 6 790 respondents (3 930 learners and 2 860 general adult population), 650 voluntary comments, six individual interviews, and a 20 member focus group discussion, were used. Photographic images and personal observation provided meaning to results by presenting the quantitative and qualitative data visually. A blended methodological approach was used to analyse the data using descriptive statistics and a t-test for variance. Tables, bar graphs and pie charts were the various representative techniques deployed during the analysis. Data were analysed comparing statistical input and responses of the learners and the general population. Results presented show that the studied community is aware of some hazards associated with coal from the mining process to indoor combustion. The community studied is aware of the need for pro-active measures to protect their community. Members of the community are not aware of company decisions affecting the community with regard to coal hazards. They are also unaware of the existence and application of environmental legislation. Awareness was not linked to education or information obtained from a reliable source, such as a mining company or a local authority. It was based on personal experience, longevity of dwelling in the community and observation of the health conditions of relatives and friends. Some voluntary comments from the respondents and photographic images are included to support the community’s outlook. The research concluded that there are more unidentified hazards in the community than were covered in the structured questionnaires. The responses received to the questionnaires exposed the mining industry as being dismissive when it came to applying the law. This evasive behaviour emanates from the laxity of the enforcement departments and responsible authorities. More needs to be done to attain the requirements of the Johannesburg Plan of Implementation as agreed upon at the 2002 World Summit on Sustainable Development.
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Joubert, Casper. "The quality of Environmental Management Programmes (EMPRs) within the coal mining industry in South Africa / Casper Joubert." Thesis, 2015. http://hdl.handle.net/10394/15317.
Full textAbstract:
Mining operations negatively impact the environment and, as a result, South African legislation requires that, as part of an Environmental Impact Assessment, an Environmental Management Programme (EMPRs) be developed and implemented to manage all the impacts identified. The Coal Mining Sector was selected for this research because of the important role it plays within the South African economy. In this research, the quality of Environmental Management Programmes within the Coal Mining Sector of South Africa was reviewed. Based on Lee and Colley’s method for reviewing the quality of Environmental Impact Reports, a review package was developed and used for the evaluation of the quality of the Environmental Management Programmes. According to the results, 62% of the Environmental Management Programmes achieved satisfactory quality grades despite omissions and inadequacies still being present. Distinct areas of weaknesses were found, such as confusion about what is required from an EMPR according to the guidelines and regulations of Department of Mineral Resources. Some EMPRs were generic documents with action plans presented that could not practically manage the impacts identified, and in some cases the Environmental Assessment Practitioner (EAP) did not possess the technical knowledge of the mining operation to develop effective action plans to manage the impact identified. All these factors influenced the outcome of the quality evaluation of the EMPRs reviewed.<br>Master of Environmental Management, North-West University, Potchefstroom Campus, 2015
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Trčková, Barbora. "Poruchy staveb na poddolovaném území městské části Kladno-Švermov." Master's thesis, 2010. http://www.nusl.cz/ntk/nusl-295901.
Full textAbstract:
The thesis is dealing with construction damages in the undermined Kladno-Švermov district. This area is situated in the Kladno Coal district, which is a part of the Kladno- Rakovník Basin. Kladno-Švermov is one of the places which have been affected by mining activity for more than last 150 years. Firstly the historical documentation, structure development and engineering geology investigations were reviewed. Secondly the area was investigated and the catalogue of 39 documentation points was made. The aim was to register visible construction damages on buildings, roads, or bricked fences, which could be caused by effects of undermining. The consequences of undermining in the Kladno-Švermov district are still apparent and the impacts of the hard coal mining are not finished. The main impact in the area is represented by subsidence basin. It has affected all the area and the damages are mainly caused by unequal descent. They are visible on some buildings, roads, or fences. Attachment number 3 is represented by commented catalogue of the main damages in the area and map of the undermined district with documentation points is enclosed as an attachment number 4.
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Zimmermann, Karsten. "Prognose und bergschadenkundliche Analyse dynamischer Bodenbewegungen durch oberflächennahen Steinkohlenbergbau in den USA." Doctoral thesis, 2010. https://tubaf.qucosa.de/id/qucosa%3A22748.
Full textAbstract:
Der untertägige Abbau von Steinkohle führt zu Bewegungen des überlagernden Gebirges und der Tagesoberfläche. Eine Bewegungsprognose ist im Hinblick auf entstehende Bergschäden weltweit von großer Bedeutung. In dieser Arbeit wird untersucht, ob eine Prognose von Bodenbewegungen im amerikanischen Steinkohlenbergbau mit einem in Europa bewährten Verfahren, einem dynamischen stochastischen Senkungsmodell, möglich ist. Dazu wurde eine Literaturstudie über den bisherigen Kenntnisstand in den USA durchgeführt, abbaubegleitende Bodenbewegungsmessungen aus dem Steinkohlengebiet der Appalachen ausgewertet und durch Modellrechnungen nachgebildet. Es wurde darüber hinaus untersucht, welchen Einfluss die spezifischen Abbaubedingungen und die räumliche und zeitliche Abbauführung auf die Größe und Dynamik von Bodenbewegungen haben. Die theoretischen und praktischen Untersuchungen zeigen einen deutlichen Know-how Vorsprung des europäischen Bergbaus in den Bereichen der Senkungsmodellierung und Bewertung abbauinduzierter Bodenbewegungen und belegen die Anwendbarkeit des Senkungsmodells. Es wurden wichtige Erkenntnisse gewonnen, die Möglichkeiten und Grenzen einer Optimierung des Abbauzuschnitts und der zeitlichen Abbauführung im Sinne einer bergschadensmindernden Abbauplanung aufzeigen. Die Arbeit trägt zur Verbesserung der bergmännischen und markscheiderischen Abbauplanung im Steinkohlenbergbau bei.