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Design, analysis and manufacture of a Rocprop dome endBolton, Jason Charles 16 August 2012 (has links)
M.Ing. / Safety within the mining industry is a primary concern for everyone involved. More specifically, active below-ground stope support for South African Mines is becoming increasingly important due to a renewed emphasis on the safety and well-being of the people actually working underground. It is imperative that all stope support systems are rigorously tested, continuously, both under laboratory conditions and in-situ to prove their performance and manufacturing standards. The Rocprop was initially manufactured in 1995 with the first two hundred props being installed at East Driefontein Consolidated Gold Mine in the Carletonville area. In the three years since the first introduction over three hundred thousand Rocprops have been manufactured and sold to South African Mines with the number steadily increasing. The Rocprop is a tubular support consisting of two tubes — a Ø139mm 'inner' tube and a Ø152mm 'outer' tube. One end of each tube is sealed by dome ends which are welded onto the tube mouths. The two tubes, cut to identical lengths, fit inside one another and extend telescopically during installation. Once the desired height has been reached, leaving enough tube overlapping to ensure the support does not buckle, the wedge is hammered in locking the prop at that height. The water is then removed after which the prop will provide active support of the rock mass above it. One of the components responsible for the Rocprops success is a dome end. This is either a forging or a pressing welded onto each end of the support and allows continual concentric loading throughout the life of the Rocprop. At present the dome ends are pressings, manufactured into hemispheres from 10mm mild steel plate in one action. The reason for the Rocprop's success is its performance characteristics. It's all metal construction, ease of installation, reliability and predictability in both seismic and static conditions, fire resistance, blast resistant, economically viability and versatility have made the prop successful. Reasons for the research were to investigate the dome end forming process in general and to investigate current numerical analysis techniques ability to predict loads during manufacture, the final shape, spring-back and other local deformation areas. Also to investigate alternate manufacturing methods such as cold forming, which provides advantages such as better mechanical properties and higher structural capabilities. The use of alternate materials in the Rocprop manufacture has been an ongoing process for MSP, manufacturer and current licensee holder of the Rocprop. A substitute for the current dome end manufactured from mild steel was investigated. For the substitute to be viable the material should be stronger, weigh less and be cost effective. In depth knowledge about the forming of the dome end at various velocities was gathered, providing information for further optimisation of the component.
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Water in the coal mining industry : an assessment of water management issues facing the coal mining industry of the Witbank and Middelburg Dam catchmentsChelin, Monique Josette 29 May 2006 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MSc)--University of Pretoria, 2007. / Geography, Geoinformatics and Meteorology / MSc / Unrestricted
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The role of arbuscular mycorrhizal fungi in the biotransformation of coal and application in dump rehabilitationMukasa-Mugerwa, Thomas Tendo January 2007 (has links)
Fundamental processes underpinning the biotransformation of coal by fungal biocatalysts have been intensively investigated, however, limited large-scale industrial applications using such systems have been reported. The un-anticipated sporadic growth of Cynodon dactylon on the surface of un-rehabilitated discard coal dumps has been noted and this was found to be coupled with the breakdown of coal into a humic soil-like material in the top 1.5 metres of the dumps. Extensive fungal growth was observed to be associated with the Cynodon dactylon root system and examination of plant roots indicated the presence of mycorrhizal fungi. Analysis of the Cynodon dactylon plant roots around which coal biotransformation was occurring confirmed the presence of arbuscular mycorrhizal colonisation with the species Glomus clarum, Paraglomus occultum, Gigaspora gigantea and Glomus mosseae identified to be associated with the plants. Further molecular characterisation of non-mycorrhizal rhizospheric fungi showed the presence of fungal species with coal-degrading capabilities that most likely played a role in the coal biotransformation observed. The discard coal dump environment was simulated in pot and column studies and coal biotransformation was reproduced, with this process enhanced by the addition of mycorrhizal and non-mycorrhizal rhizospheric fungal inocula to the environment. Mycorrhizal and non-mycorrhizal species in the inoculum were re-isolated from the simulated environment fulfilling a number of Koch’s postulates and indicating a causal role in the biotransformation of coal. An inversion of conventional mycorrhizal colonisation was demonstrated in this system with reduction in extraradicular presence and an increase in intracellular colonisation compared to soil controls. A descriptive model was formulated suggesting a two-part fungal system involving organic carbon and nutrient exchange between the plant, mycorrhizal fungi and non-mycorrhizal coal-degrading rhizospheric fungi ultimately resulting in the biotransformation of coal. The biotransformation observed was comparable to reports of “rock-eating fungi”. Results suggest that the biological degradation of coal in situ with the production of a soil-like substrate could provide a feasible method of discard coal dump rehabilitation as well as provide a humic-rich substrate that can be utilised in further industrial applications.
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Ekonomické aspekty rekultivace hnědouhelného lomu na Mostecku / Economic aspects of reclamation of brown coal quarry near the town MostŠtemberová, Daniela January 2009 (has links)
The master thesis deals with reclamation of brown coal quarries from different perspectives. It focuses on the various options of reclamation of quarries. It evaluates the economic benefits and costs, integration into the way of rehabilitation needs and the future use of this reclamation. It defines a way how to optimise the use of devastated land. This thesis is focused on the reclamation of region Most specifically on the brown coal quarry called Ležáky - Most. It considers if hydrologic variant of reclamation for the quarry is the best. It describes other possibilities of reclamation that have been considered. The master thesis introduces the reasons for the selection of the hydrologic reclamation. It reviews the complexity of the hydrologic reclamation of the quarry Ležáky -- Most, its effect on the environment, social sphere and the further societal use. The main objective is to analyze the total effectiveness of quarry Ležáky - Most, if the mining was profitable taking into account all its costs and revenues.
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Mining Interruption: Life, labor and coal after the Soma mine disasterAz, Elif Irem January 2023 (has links)
“Mining Interruption” tackles the question of how to make sense of disaster by exploring the Soma mine disaster. On May 13, 2014, an explosion in the Eynez underground lignite coal mine caused a fire that blocked the exit, sealing in 301 mineworkers who died of carbon monoxide poisoning in the town of Soma, in the city of Manisa, in Aegean Turkey. While the European Union was becoming relatively greener next door, coal extraction had begun to increase in Turkey after the Justice and Development Party [Adalet ve Kalkınma Partisi] came to power in early 2000s. The relative decline of coal in the Global North paved the way for increased amounts of internal coal extraction and consumption in the energy geographies of the Global South and other non-Western countries as well as of Indigenous lands. The shift created biopolitically, socially, and technologically renewed forms of exploitation of labor, bodies, and nature, which contextualize the Soma mine disaster.
Based on 18 months of ethnographic fieldwork and 68 open-ended interviews conducted in the Soma Coal Basin, this dissertation presents one constellation of the disaster by exploring four figures—The Accidented, the Bride, the Deserving, and the Striker—both as effects and as ongoing temporalities of the disaster. It contributes to critical disaster studies by defining and studying disaster not as a category of event, but as a concept through which multiple temporalities, lived experiences, and knowledges hang together. This loose definition of disaster is complemented by a reinterpretation of Walter Benjamin’s take on one of Bertolt Brecht’s most important dramaturgical techniques: interruption.
In the dissertation, interruption is re-conceptualized as an experiential (hence temporal) concept that captures out-of-the-ordinary moments or flashes that interrupt everyday life in a way that permits a reevaluation of historical-material conditions. Interruptions are openings through which people may or may not follow an accidental course of action in order to overcome, better deal with, or politically respond to their conditions. The multiplicity of interruptions that are integral to the ongoing Soma mine disaster intersect with labor, fossil fuel production and its toxic effects, disability/debility, gendered oppression, disaster management, and social assistance. Some of these interruptions are experienced as rupturing events while others are perceived below the threshold of the event as such—as noneventful or not-so-eventful sensibilities, intensities and material changes. Each figure in question is a constellation in itself, a web of interdependencies, ruptures and materialities formed among human beings, state actors, coal, land, tobacco and other plants, limbs, organs, and names.
In “The Accidented,” by examining mineworkers’ experiences and the terminology of becoming accidented (a direct translation of the term kazalanmak [in infinitive form]) through work accidents, the dissertation presents a critique both of existing disability assessment techniques and processes, and of understandings of disability as identity, which peripheralize labor-related and other experiences of (dis)ability and debility.
In “The Bride,” by surveying the pervasive rumors about the widows of the 301 mineworkers, and their naming by the townspeople as “the brides,” the dissertation studies the differential treatment of the families of the 301 and the rest of the mining community through the state’s twofold disaster management strategy, and the ways in which people deal with this treatment through gossip, resentment, and kinship ties. In so doing, the dissertation also explores how affinal kinship relations have been transformed in the region due to the rise of coal mining, which coincides with the heightened neoliberalization of agriculture.
In “The Deserving,” by investigating the materiality and movement of the lignite coal that is known as “Soma coal,” the dissertation articulates the ways in which the lives and desires of working-class and peasant communities have been reshaped through coercion, patronage, ideological interpellation, and the subjectivizing effects of Soma coal. It presents Soma coal as a pedagogical infrastructure that has emerged through the materiality of coal, and the regimes and networks of labor and welfare provision in contemporary Turkey.
Finally, through the figure of “The Striker,” the dissertation examines the three-year long compensation struggle and protests of Soma and Ermenek mineworkers (2019–2021) as a set of emergency strikes that interrupted various processes, technologies, social networks, and modes of life that are formally and/or really subsumed within capital. The concept of “emergency strike” is used in order to encapsulate a form of strike that emerges with whatever means available in a given context, and as a collective act of seizing perceived last chances. This discussion builds on a recent wave of theorization concerning forms of unconventional strike that aim to disarticulate mechanisms and processes of real subsumption and/or state sovereignty. The dissertation shows how mineworkers organized against the backdrop of the Soma mine disaster. In doing so, it demonstrates how mineworkers re-exceptionalized their living and working conditions under a state of exception that has become the rule in Turkey since the 2016 coup attempt while it had already become the rule in the Soma Basin after May 13, 2014.
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The effects of the pressure arch upon multiple seam miningHudock, S. D. January 1983 (has links)
The coal fields of Appalachia of many contiguously mineable coal seams. Common practice in mining multiple seams is to extract the seams in a descending order. However, the mining sequence may still be based on seam ownership, availability of the seam and the general economic situation, net on ground control considerations.
One of the major ground control mechanisms that must be considered in the design of a mine is the arching of stresses around a previously mined lower seam. This investigation deals with the extent and magnitude of the stresses above an underground opening. The finite element approach was utilized to determine the extent and magnitude of stresses for various widths of mine opening, depths of cover and overburden material. This information can then be used as an approximation of the stresses that may be encountered in an actual mining situation. / Master of Science
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Longwall mining, subsidence, and protection of water resources in VirginiaRoth, Richard A. January 1989 (has links)
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. / Master of Urban and Regional Planning / incomplete_metadata
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Geologic and geotechnical controls on the stability of coal mine entriesKane, William F. January 1985 (has links)
Roof and rib failures in underground coal mines are one of the major problems facing the industry today. In addition to safety considerations, the resulting economic impact of such failures is staggering. Uncovering and replacing buried and damaged equipment and clearing entries can account for a large expenditure in lost man-hours and machinery. Yet, because of the complex nature of their formation, geological variability, and structural characteristics, coal mine roof strata are one of the least controllable of all mine design parameters. This is especially true along the leading (southeastern) edge of the Appalachian coalfields where considerable faulting and movement have contributed to hazardous coal mining roof conditions.
For this research, a detailed study of several mines, in the southern Appalachian coalfields, was undertaken to determine the most prominent geomechanical factors affecting roof stability and to evaluate their influence in promoting unstable ground conditions. In order to accomplish this task, the major geological and geomechanical features found to be detrimental to the coal mine roof within the Appalachian basin were identified and mapped in four Virginia mines.
Statistical processing by chi-square and linear regression analysis as well as analytical analysis by the finite element method were used to determine the influence of geology, mine-layout, and support methods on roof stability. It was found that some easily determined parameters can be successfully used to predict potentially unstable areas. A simplified roof classification system was developed based on the geomechanical parameters, which can be used to assess the stability of a particular roof type. A Roof Rating Index was also devised capable of expressing the probability of failure under a given set of geomechanical conditions. / Ph. D.
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The effect of organisational restructuring at Xstrata Coal South Africa and its impact on the business culture at the Tweefontein divisionAlberts, Rasmus Stephanus 12 1900 (has links)
Thesis (MBA (Business Management))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Xstrata Coal South Africa (XCSA) embarked on a restructuring exercise towards the end of 2005 to enable the organisation and its management to adapt to the pressures and requirements of an ever-changing South African coal industry. The executive team of XCSA felt that some of the business units were too large to be effectively managed by one general manager and his/her management team. The Tweefontein and Impunzi business units fell into this category. Further, the executive team felt that the existing organisational structures on the mines were unable to effectively manage the demands coming from an ever-changing coal industry. Most such demands emanated from sustainable development issues: workplace safety, environmental management, health-related concerns to do with the employees and community development around the mines. The restructuring took place towards the end of 2005, not long after the restructuring of the business performance went into decline. The author of this thesis, as the General Manager of the Tweefontein Complex from the beginning of 2006 until mid-2008, was responsible for the day-to-day management of the division at the time. After explaining the need for restructuring, as well as how the structure was changed, the author will describe a comprehensive literature research study. The aim of such a study is to create a common understanding with the reader of the principles relating to culture, leadership and change management. The author then compares the two climate assessments of the organisational culture of the Boschmans Colliery undertaken during 2005 prior to embarking on the restructuring exercise, and of the Tweefontein Complex undertaken during 2007, on completion of the restructuring. Boschmans Colliery employees now constitute most of the underground and surface operations areas of the Tweefontein Complex. The organisational culture of the Tweefontein Complex was found to have been influenced by the restructuring exercise. The author concludes with recommendations on how the organisational culture of XCSA as a whole could be aligned. Chief among the recommendations are that: • A cultural alignment programme should be implemented to create a common organisational culture across XCSA. • A leadership development programme should be implemented to promote the desired organisational culture. • A communication strategy should be implemented to support the cultural alignment programme. • A branding campaign should be launched to strengthen the image of XCSA within the surrounding community. / AFRIKAANSE OPSOMMING: Xstrata Coal South Africa (XCSA) het aan die einde van 2005 besluit om die besigheid te herstruktureer om aan te pas by die veranderende aard van die Suid-Afrikaanse steenkoolindustrie. Die gevoel van die uitvoerende komitee was dat sekere van die besigheidseenhede te groot was om effektief deur een algemene bestuurder, bestuur te word. Die Tweefontein- en Impunzi-besigheidseenhede het in die kategorie geval. Verder het die uitvoerende kommitee gevoel dat die bestaande bestuurstruktuur per myn nie voldoende was om al die verwagtinge vanuit 'n vinnig veranderende steenkoolindustrie effektief te kan bestuur nie. Die vernaamste verwagtinge van die vinnig veranderende industrie was die vanuit die veld van Volhoubaarheid, naamlik veiligheid op myne, omgewingsbewustheid, gesondheid van die werknemers, sowel as die opbou van die gemeenskap. Die herstrukturering het aan die einde van 2005 plaasgevind en nie lank na die herstrukturering nie het die prestasie van die besigheid drasties afgeneem. Die skrywer was die Algemene Bestuurder van die Tweefontein Complex vanaf die begin van 2006 tot die middel van 2008, en was verantwoordelik vir die dag-tot-dag-bestuur van die afdeling. As deel van die studie sal die skrywer eerstens poog om die redes vir die herstrukturering te gee en ook hoe die nuwe struktuur daar uitsien. Tweedens sal die skrywer 'n deeglike literatuurstudie verskaf om 'n gemeenskaplike verstandhouding tussen die skrywer en die leser oor die beginsels van kultuur, leierskap en veranderingsbestuur te skep. Derdens sal die skrywer die resultate van twee klimaatstudies ontleed wat op die besigheidskultuur van die Boschmans-steenkoolmyn in 2005 voor die herstrukturering gedoen is en een wat in 2007 op die Tweefontein Complex na die herstrukturering gedoen is. Die werknemers van die Boschmans-steenkoolmyn maak tans die grootste gedeelte van die Tweefontein Complex se ondergrondse en aanleg- en logistieke afdelings uit. Na aanleiding van die analise van die twee klimaatstudies, bevind die skrywer dat die herstrukturering 'n daadwerklike invloed op die kultuur van die Tweefontein Complex gehad het. Die skrywer maak dan na gelang van sy bevindinge aanbevelings oor hoe die kultuur van Xstrata Coal South Africa (XCSA) as 'n geheel belyn kan word. Sy belangrikste aanbevelings is as volg: • Die implementering van 'n kultuurbelyningsprogram om 'n gemeenskaplike besigheidskultuur regoor Xstrata Coal South Africa (XCSA) daar te stel. • Die implementering van 'n leierskapsontwikkelingsprogram wat belyn is met die verlangde besigheidskultuur. • Die implementering van 'n kommunikasiestrategie wat die kultuurbelyningsprogram ondersteun. • Die loodsing van 'n Xstrata Coal South Africa (XCSA) bemarkingsveldtog am Xstrata Coal se beeld in die gemeenskap te bevorder.
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A method for establishing base-line soil loss rates on surface mine sitesFlack, Paul E., 1960- January 1989 (has links)
Surface mining operations require a comparison of post-mining erosion rates with pre-mining soil loss to ascertain if remedial measures are needed. In this study the Universal Soil-Loss Equation (USLE) was modified to reflect conditions of western rangelands to develop a procedure for estimating pre-mining soil loss rates. The modification used back-calculation for the C-Factor and an adjusted R-Factor based on storm size. Soil loss simulation based on stochastic precipitation patterns is appropriate to the site--the La Plata mine area in northern New Mexico--and increases the flexibility of the USLE as a soil loss predictor for western rangelands.
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