Dissertations / Theses on the topic 'Mining Geomechanics'
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Xu, Guangquan. "Wellbore stability in geomechanics." Thesis, University of Nottingham, 2007. http://eprints.nottingham.ac.uk/11475/.
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Borehole instabilities can be encountered at any stage in the life of a well and they are the main cause of drilling difficulties, resulting in substantial expenditures, expensive loss of time, sometimes even in the loss of part of or even whole boreholes. The main aim of this research is to use new method and theory in geomechanics to conduct the stability analysis of wellbore. The cavity contraction theory is used to get the new elastic-perfectly plastic solutions for vertical borehole with anisotropic stress field. The solutions for Mohr-Coulomb and Hoek-Brown criteria are derived in this paper. A new alternative criterion, which is to limit the radius of plastic zone around borehole, to predict the wellbore instability was also recommended. The finite element code ABAQUS is applied to analyse the mechanical behaviour of wells with different inclinations and different azimuths. A Generalized Plane Strain Model is used in the calculation. The failure wellbore pressure, borehole closure, plastic zone distribution of different direction wells are given in this paper. In order to accurately predict the wellbore behaviour in soft and porous rocks, a suitable and advanced constitutive model of rocks is the key issue of the borehole instability research. A new model, called CASM (Clay And Sand Model) which is based on critical state theory and formulated in terms of the state parameter concept is applied in this research. The non-coaxiality theory is incorporated into CASM to analyse the wellbore stability. Compared with coaxial model, non-coaxial model gives more pessimistic results. However, it was found that the influence of non-coaxiality on wellbore stability depended on initial conditions of wellbore.
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Raffaldi, Michael J. "Static and Dynamic Discrete Element Modelling of Slender Coal Pillars." UKnowledge, 2015. http://uknowledge.uky.edu/mng_etds/21.
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Highwall mining is a mining method used in surface coal operations that involves driving a series of parallel entries into the exposed coal seam at the highwall face under an unsupported roof leaving behind a series of long, but very slender coal pillars. Highwall mining often occurs simultaneously with production blasting taking place in other areas of the mine. Although no failures of highwall pillars have been attributed to nearby blasting, numerical modelling presents an inexpensive means of investigating the possible effects of strong ground motion on the stability of these pillars. This thesis documents the development of a discrete element rock mass model and its application to the simulation of both static and fully dynamic highwall pillar simulations. The approach is geared toward parameter analysis and mechanism identification rather than exact prediction. Some conclusions are made regarding the potential effects of blast vibration on highwall coal pillars and general excavations in rock. The limitations of the modelling approach are discussed and suggestions for future research are proposed.
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Gurgenli, Hakan. "Geomechanical and weathering properties of weak roof shales in coal mines." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4717.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains ix, 99 p. : ill. (some col.), maps (part col.). Includes abstract. Includes bibliographical references (p. 77-81).
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Eitzenberger, Andreas. "Inventory of geomechanical phenomena related to train-induced vibrations from tunnels." Licentiate thesis, Luleå tekniska universitet, Geoteknologi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18147.
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Banverket is expecting that the number of railway tunnels in densely populated areas will increase over the next 20 years due to the lack of available space on the ground surface, but also since the railway is considered an environmentally friendly solution of transportation for the future. The need for good predictions of vibration and noise levels in dwellings along the planned tunnels is therefore evident. Due to lack of understanding of the propagation of train-induced vibrations from tunnels in rock a research project has been initiated by Banverket. This thesis constitutes the first stage of that project. In this thesis, the propagation of vibrations through a rock mass has been reviewed. The emphasis has been on wave propagation in hard rock masses. Areas, such as the generation of vibrations at the train-rail interface, the response of buildings and humans, national and international recommended noise and vibrations levels, and possible countermeasures are briefly reviewed as well. Finally, suggestions for the continued research are presented. The propagation of waves is influenced by attenuation along the propagation path. The attenuation can either be through geometric spreading, energy loss within the material, or reflection and refraction at boundaries. In a rock mass, where heterogeneities of various scales are present, the attenuation of (train-induced) waves through the ground therefore mainly depends on the properties of the discontinuities. Theoretical models of wave propagation across individual fractures have been presented in the literature. These models can be used to study the attenuation at the fracture for different combinations of joint stiffness, impedance, and angle of incidence. Also multiple parallel joints can be theoretically analysed. The attenuation of low-frequency waves is more prominent in weak rock masses and virtually negligible for hard rock masses. An increased amount of random oriented joints, faults and boundaries increases the attenuation of the waves, but is not possible to study with the aid of theoretical models. The rock mass is in most cases inhomogeneous due to all heterogeneities present. Despite this fact, the rock mass and soil is always treated as an isotropic, homogeneous material in the analyses of ground-borne noise and ground-borne vibrations. This concerns both numerical and empirical methods. Thus, there is a lack of a method that considers the influence of various heterogeneities present in a rock mass on the propagation of waves. Future research regarding train-induced vibrations should focus on combining the models of attenuation in the material with the models of attenuation across joints. Thereafter, conceptual models should be used to determine the propagation of low-frequency waves in a rock mass containing various amounts of heterogeneities (from isotropic to highly inhomogeneous) which should be compared to the theoretical methods available. Once the behaviour of waves in an inhomogeneous rock mass has been established, conceptual models should be used together with measurements from a few well documented cases. From the results of the analysis, guidelines for analysis of railway tunnels with regard to ground-borne noise and ground-borne vibrations should be established.Banverket uppskattar att antalet järnvägstunnlar I tätbebyggt område kommer att öka inom de närmaste 20 åren, dels på grund av att tåg är ett miljövänligt transportsätt samt att marken i tätbebyggda områden är begränsad. Det finns därför ett stort behov av tillförlitliga metoder för att bedöma vilka vibrations- samt stomljudsnivåer som kommer att uppstå i bostäderna längs den planerade järnvägen. För att öka förståelsen har Banverket initierat ett forskningsprojekt där denna avhandling utgör den första delen. I denna avhandling har vågors propagering genom bergmassan studerats. Områden som uppkomsten av vibrationerna, hur människor och byggnader påverkas av vibrationer, nationella samt internationella standarder, samt åtgärder för att minska vibrationer har studerats. Slutligen ges förslag på fortsatt forskning.När vågor propagerar genom ett material dämpas vågen. Dämpningen kan bestå av geometrisk dämpning, energiförluster till materialet, eller reflektion och refraktion vid materialgränser. I en bergmassa som innehåller heterogeniteter i varierande skala orsakas dämpningen av vågorna främst av sprickornas egenskaper. Teoretiska modeller av vågors propagering genom en spricka finns rapporterade i litteraturen . Dessa modeller kan användas för att studera en sprickas inverkan på vågor för olika kombinationer av sprickegenskaper, till exempel sprickstyvhet, impedans eller infallsvinkel. Det finns även teoretiska modeller för att studera parallella sprickors inverkan på vågor. Dämpningen av vågor med låg frekvens är dominerande i bergmassor av låg kvalitet men i princip försumbar i hårt friskt berg. Ökad förekomst av sprickor, förkastningar, och materialgränser ökar dämpningen. Det är dock svårt att studera sådana bergmassor på ett bra sätt med analytiska modeller.En bergmassa innehåller en mängd olika typer av heterogeniteter. Trots detta antas oftast bergmassan vara ett isotropt, elastiskt och homogent material vid analyser av stomljud och vibrationer. Detta gäller både numeriska och empiriska modeller. Det finns således ingen metod som beaktar sprickors egenskaper vid analyser av vibrationer i bergmassor. I den fortsatta forskningen bör man studera möjligheten att kombinera metoder som används för att bestämma materialdämpning med metoderna som används för att bestämma dämpningen för sprickor och materialkontakter. Detta skulle möjliggöra utvecklingen av enkla regler för hur bergmassan ska modelleras vid analyser av stomljud. Därtill bör konceptuella modeller användas för att studera vågors propagering genom material med varierande grad av uppsprickning. Dessa enkla modeller bör sedan jämföras med de teoretiska modellerna. De konceptuella modellerna bör sedan kombineras med studier av något eller några väldokumenterade tunnlar. Utifrån analyserna bör det vara möjligt att skapa enkla regler för hur bergmassan ska modelleras då man studerar stomljud.
Godkänd; 2008; 20081211 (ysko)
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Parapuram, George Kurian. "Prediction and Analysis of Geomechanical Properties of the Upper and Middle Bakken Formation Utilizing Artificial Intelligence and Data Mining." Thesis, University of Louisiana at Lafayette, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10682660.
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To efficiently produce oil from unconventional reservoirs, it is imperative to determine and understand the geomechanical properties of the formation. But, due to the high cost of obtaining these properties from geomechanical well logs, businesses are looking for all possible ways to cut cost. The plummeting oil prices have been reflected in company spending and have driven companies to prioritize focusing attention on the rising production costs and venture all possible ways to reduce these costs. The real challenge is how to preserve these profitable gains? There is a need for an alternate and cost- effective way to obtain geomechanical properties of the rocks.
By utilizing Data Analytics, Data Mining, and ANN, patterns are observed between parameters from large amounts of data and, thus, important information regarding the formation can be understood. In this study, a relationship between conventional well logs and geomechanical well logs are established. Properties such as Young’s Modulus, Poisson’s Ratio, Shear Modulus, Bulk Modulus, and Minimum Horizontal Stress are determined from Conventional Logs such as Gamma Ray and Density Log utilizing ANN. Ultimately, data-driven models are developed to predict accurate geomechanical properties for future wells of the Upper and Middle Bakken Formation. Finally, the efficacy of the data-driven models achieved is tested on randomly selected new wells that were not used in the training of the model. The accurate prediction and analysis of these properties help in better reservoir characterization and efficient production from the future wells in the Bakken Formation.
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Bhering, Apolo Pedrosa. "Classificação do maciço rochoso e caracterização das brechas da mina subterrânea de Vazante-MG." Universidade Federal de Viçosa, 2009. http://locus.ufv.br/handle/123456789/3718.
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Previous issue date: 2009-09-22This dissertation describes the Vazante underground mine rock mass and some important breccias geomechanics features, or bimrocks, which occur in the underground. Systematic geologic-geotechnics mappings of the main levels of the underground mine was carried out, allowing the individualization of four families of main discontinuities, besides the preserved sedimentary bedding and the foliation. The mappings were done following the geomechanics classification RMR and the Q system, supplying correlation between the methods for Vazante's lithotypes. A new campaign of uniaxial tests for the determination of intact rock strength was carried out and the RQD values for each classified area had been determined by statistics analyses. The results were discussed according to each parameter and peculiarities found in each distinct rock mass. The breccias, a rock type which is not very accessible in the geotechnical literature, had been characterized according to the volumetric block proportion (VBP) and strength to simple compression. The values of VBP had been found from the analyses obtained with the aid of the Leica Qwin software for the binarization of the digitalized images. There has also been presented the correlation between the simple compression and the percentages of the main chemical elements that constitutes the Vazante breccias, such as zinc, iron, calcium, magnesium and silicon.
Esta dissertação descreve o maciço rochoso da mina subterrânea de Vazante e algumas importantes características geomecânicas das brechas, ou bimrocks, que ocorrem em subsolo na área da mina. Realizaram-se mapeamentos geológico-geotécnicos sistemáticos dos principais níveis da mina, que permitiram a individualização de quatro famílias de descontinuidades principais, além do acamamento sedimentar preservado e a foliação. Os mapeamentos foram executados seguindo a classificação geomecânica RMR e o Sistema Q, fornecendo correlações entre esses métodos para os litotipos de Vazante. Foi realizada uma nova campanha de ensaios uniaxiais para determinação da resistência da rocha intacta e análises estatísticas para setorização do RQD. Os resultados encontrados são discutidos em função de cada parâmetro e particularidades encontradas em cada maciço rochoso. As brechas, tipo de rocha pouco descrito na literatura geotécnica, foram caracterizadas em função da proporção volumétrica de blocos (VBP) e resistência à compressão uniaxial. Os valores de VBP foram obtidos a partir de análises realizadas com o auxílio do software Leica QWin para binarização das imagens digitalizadas. São apresentadas também as correlações entre resistência à compressão simples e os teores dos principais elementos químicos constituintes das brechas de Vazante, como zinco, ferro, cálcio, magnésio e silício.
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Старотіторов, Ігор Юрійович, Игорь Юрьевич Старотиторов, and I. Y. Starotitorov. "Обґрунтування параметрів кріплення підготовчих виробок залізорудних шахт Кривбасу, що пройдені в неоднорідному породному масиві." Дисертація, Видавництво НГУ, 2011. http://ir.nmu.org.ua/handle/123456789/103.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.15.09 – «Геотехнічна і гірнича механіка». ДВНЗ «Національний гірничий університет», Дніпропетровськ, 2011.Диссертация на соискание ученой степени кандидата технических наук по специальности 05.15.09 – «Геотехническая и горная механика». ГВУЗ «Национальный горный университет», Днепропетровск, 2011.
Dissertation for Ph.D. degree in the specialty 05.15.09 – "Geotechnical and Rock mechanics". State higher educational establishment "National Mining University", Dnipropetrovsk, 2011.
У дисертації вирішена актуальна науково-технічна задача підвищення стійкості підготовчих виробок залізорудних шахт Кривбасу. Виконаний аналіз витрат, пов'язаних з підтримкою гірничих виробок. Організовані та проведені натурні вимірювання конвергенції в гірничих виробках. Проведені лабораторні випробування основних вміщуючих порід і руди, в тому числі і за межею міцності. Виконаний аналіз існуючих теорій міцності. Методом скінченних елементів виконане моделювання процесу руйнування гірських порід в об'ємному напруженому стані і в одноосьовому за межею міцності. Розроблений алгоритм розв'язання пружнопластичної завдачі з урахуванням можливості руйнування гірських порід за межею міцності. Для гірничо-геологічних умов ш. «Родіна» виконаний геомеханічний аналіз умов підтримки підготовчих виробок з використанням удосконаленого алгоритму розрахунку. Виконані розрахунки параметрів анкерного кріплення для розглянутих умов.
В диссертации решена актуальная научно-техническая задача повышения устойчивости подготовительных выработок железорудных шахт Кривбасса. Выполнен анализ затрат, связанных с поддержанием горных выработок. Организованы и проведены натурные измерения конвергенции в горных выработках, что позволило установить закономерности их деформирования в зависимости от комплексного показателя разработки, и на этой основе вести прогноз состояния геомеханической системы “крепь – породный массив”. Выполнены лабораторные испытания основных вмещающих пород и руды, в том числе и за пределом прочности. Построены гистограммы распределения предела прочности на одноосное сжатие, которое ближе всего аппроксимируеться логнормальным законом распределения. Выполнено моделирование устойчивости подготовительных выработок, пройденных в существенно неоднородном породном массиве, что позволило установить тенденции в части их поддержания. Выполнен анализ существующих теорий прочности, позволивший сравнить результаты лабораторных и теоретических исследований, и обосновать возможность использования в геомеханических расчетах теорию прочности Баландина. Методом конечных элементов проделано моделирование процесса разрушения горных пород в объемном напряженном состоянии и в одноосном за пределом прочности. Доказано, что при условии распределения прочности по логнормальному закону, кривые запредельного деформирования достаточно близко соответствуют реальным кривым деформирования. Разработан алгоритм решения упругопластической задачи с учетом возможности разрушения горных пород за пределом прочности. Для горногеологических условий ш. «Родина» выполнен геомеханический анализ условий поддержания подготовительных выработок с использованием усовершенствованного алгоритма расчета. Выполнены расчеты параметров анкерной крепи для рассматриваемых условий. Натурные замеры показали, что с учетом поправочных коэффициентов алгоритм расчета позволяет достаточно точно вести прогноз основных геомеханических параметров. На основе выполненных исследований разработана и принята к использованию на шахтах ОАО «КЖРК» «Методика оценки устойчивости подземных выработок на рудниках Кривбасса». Предполагаемый экономический эффект от внедрения результатов исследований в условиях ш. «Родина» составил 258 тыс. грн./год.
An actual scientific and technical problem of improving the stability of development workings for Krivbass iron ore mines is solved in the work. The analysis of the costs associated with maintaining mine workings is made. Situ measurements of convergence in the mines are organized and carried out. Laboratory testing the main enclosing rocks and ores, including compressive strength testing, are made. The analysis of existing strength theories is made. Simulation of rock failure in a complex stress state and in uniaxial compressive strength is done using finite element method. An algorithm for the solution of elastoplastic problem is developed. It takes into account the possibility of rocks to failure in compressive strength. Geomechanical analysis of the maintaining conditions for development workings with using an improved calculation algorithm is made for the mining and geological conditions of the "Rodina" mine. Calculations of the bolt support parameters are made for the conditions considered.
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Flora, Charanpreet Singh. "Evaluation of Slope stability for Waste Rock Dumps in a Mine." Thesis, 2009. http://ethesis.nitrkl.ac.in/1386/1/Thesis_2.pdf.
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The growing needs have been pushing the limits, to which the mining industry has to reach to lift itself to fulfill the demand. The effect can be seen from the methods of mining that have evolved over the years. The heavy machinery adopted for the extraction has been producing wastes in the form of waste rocks whose management is again of prime importance. The issues relating to the stability of these overburden dumps is catching attention worldwide from quite some time, which is quite important for the safe working in and around these monstrous structures as well as restricted availability of land. This paper deals with the stability issues of dumped slopes for a local chromite mine. The analysis cover analysis of various sections of the waste dumps from the mine including material properties, strength values, bench height and angle.
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Nanda, Abinash. "Correlation analysis of spontaneous heating of some SECL coals." Thesis, 2010. http://ethesis.nitrkl.ac.in/2004/1/Abinash_Nanda_final.pdf.
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The auto oxidation of coal ultimately leads to spontaneous combustion which is the major root
cause for the disastrous of coal mine. It has been a major problem in the leading producing coal countries like Australia, India and China. Therefore the assessment for this combustion is very much necessary. It depends upon different characteristics and properties of coal. Once if the combustion of coal has been occurred, it is very difficult to control which also disturbs the environment of the surroundings of the mine. The spontaneous heating susceptibility of different
coals varies over a wide range and it is important to assess their degree of proneness for taking preventive measures against the occurrence of fires to avoid loss of lives and property, sterilization of coal reserves and environmental pollution and raise concerns about safety and economic aspects of mining etc
The project deals with the thermal analysis of various parameters of coal with the spontaneous heating tendency of coal. Ten coal samples were collected from South Eastern Coalfields Limited (SECL), Coal India Limited. The project deals with correlation analysis of various parameters determined by experimental techniques. The intrinsic properties as well as
susceptibility indices of the coal samples were determined by following experimental techniques:
Proximate analysis
Calorific value
Flammability temperature
Wet oxidation potential
Differential thermal analysis
It was found from analysis that DTA – TG is the best method to assess the spontaneous hating tendency of coal in comparison to Flammability temperature and Wet oxidation potential. It was also observed that the Transition temperature obtained from the DTA – TG plot cannot be taken as a sole parameter to assess the spontaneous heating of coal, rather Stage IIB and Stage II slopes
give a better idea. It was also found that Flammability temperature method does not provide an accurate measure of spontaneous heating tendency of coal. It was found that Wet oxidation potential gave a fair enough approximation for spontaneous heating tendency for high moisture coals. However it can be taken as a parameter for spontaneous heating susceptibility as it requires less time for conduction than DTA –TG.
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Ghosh, Nilabjendu. "Permeability of Indian coal." Thesis, 2011. http://ethesis.nitrkl.ac.in/2494/1/final_thesis.pdf.
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Now-a-days there is much constraint being faced by coal mine operators from multiple stake holders. Those are local inhabitants, environmental activists, government regulatory bodies, etc. It has focused attention to develop alternate approaches to extract coal resource. Coal bed methane drainage and carbon dioxide sequestration is one of such mechanism. Determination of the permeability of coal seams has a huge bearing on the identification and selection of viable sites for carbon sequestration. In this study an attempt was made to find out the permeability of coal from Ib Valley area of Mahanadi Coalfields Limited. Samples were collected from a local mine and cores were prepared according to standard procedures. An experimental setup was designed and fabricated based on the constant head method of permeability determination and tests were carried out on the samples for over a period of time. The results obtained were compared with values reported by others’ and it was found that the setup gave a reasonable measure of the permeability of the sample.
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Das, Gorakinkar. "Analysis of Slope Stability for Waste Dumps in a Mine." Thesis, 2011. http://ethesis.nitrkl.ac.in/2504/1/Gora_Das_-_Final.pdf.
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In the civilized world mining activities are synonymous with the standard of life as well as the state of any nation. It results in both economic and uneconomic materials being generated. The Uneconomic materials (Wastes) are stacked at different places known as waste dumps. The stability of these dumps has been a major concern over the years. The problem becomes increasingly difficult with the reduced availability of land areas for dumping. In this project, the slope stability analysis for the waste dump of a local Iron Mine has been carried out. Samples are collected and tasted in the laboratory to find out different geotechnical parameters. The Factors of Safety of the various sections are calculated using Limit Equilibrium Method. Probabilistic analysis (Monte Carlo Simulation) has also been carried out to evaluate the stability of the existing design data. At the end bench design as well as corresponding safety factors has been developed based on the analysis.
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Marndi, Bhagaban. "Stability of Slopes in Iron Ore Mines." Thesis, 2011. http://ethesis.nitrkl.ac.in/2608/1/107MN018.pdf.
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Slope stability analysis is important in any opencast iron ore mine. A failure of slope in a working area of mine can give rise a significant economic losses and safety impact. The fundamental failure modes are varied and complex. Such mechanisms are governed by engineering geology condition of rock mass which are almost always unique to a particular site.
Using the FLAC/Slope software stability of slope is analysis. The work was aimed at study of stability of slopes using numerical modelling, at the same time study the different failure mechanism. The purpose of this project is to learn and assess this FLAC/Slope software. As the study of the software is easy, it can be concluded that it is user-friendly. Based on parametric studies it can be concluded that slope angle plays a major role on slope stability.
Safety factor varied from 0.63 to 1.37 for the depth of 10 m to 250 m for the slope angle of 45 degrees. It showed that with the increase in height of the bench or depth of the mine safety factor of the bench decreases indicating less stability of the concerned slope. At the depth of 100 m, the safety factor was found to be exceeding 1.2 for slope angle less than 35 degrees. Therefore, it is recommended to maintain the overall slope angle not steeper than 35 degrees, in the hypothetical mine conditions assumed in the project.
At the depth of 150m, factor of safety is 1.02, and 1.01 for the slope angles of 35 degree and 40 degrees, respectively. This indicated that the slope may be maintained with more than 1.0 safety factor at flatter than 40 degree, ensuring continuous monitoring of the stability of slope through observational approaches. It is recommended that for improving the reliability of model results, calibrations of models with actual field conditions may be taken of through piezometric monitoring and measurement of slope moments in varying geomining condition at different mine sites
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Bhoi, Manas Ranjan. "Creep behavior of rock." Thesis, 2012. http://ethesis.nitrkl.ac.in/3766/1/CREEP_BEHAVIOR_OF_ROCK_thesis.pdf.
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Mining activities of minerals play a very important role on the health and wealth of any nation. Though technology has reduced the adverse effects to a great extent, it is still experiencing unpredictable behavior of rocks. The physical and mechanical properties of rocks are important design parameters of any excavation process. The consideration of time dependence is essential for the study of deformation and fracturing processes of rock material, especially for those subjected to strong compressive and tensile stresses. In this study creep test is conducted in chromite ore under uniaxial compressive stresses. The behavior of rock is investigated as well as strength of rock. Creep behavior of rocks has been evaluated at varying stress and temperature rate. The relationship between compressive stress and time under uniaxial compression has also been developed. Finally nonlinear creep model is used to describe the creep behaviors of rocks under uniaxial compressive strength
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kumar, B. prithiraj amitesh. "Dump slope stability analysis." Thesis, 2013. http://ethesis.nitrkl.ac.in/4878/1/109MN0606.pdf.
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In this modern world mining has become an integral part of our life. Mining activities effect in generation of both economic and noneconomic materials. The noneconomic materials are stored at selected places known as waste dumps. The stability of the waste dump has been of a matter of great concern over the years. The problems increases with limiting availability of land. In this project work the slope stability analysis is carried out for the waste dump of a selected iron ore open cast mine. In this process samples are collected and tests are carried out on these samples to get different geotechnical parameters. The factor of safety of different sections of the existing design of the selected mine are calculated by the help of GALENA software. In the end new design of dump slope are proposed by optimising the bench dimensions and material properties by the help of back analysis of GALENA. Then conclusion and various recommendation are given on the basis of new design of the dump slope.
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Mohanty, Debidayal, and Sachchidanand Singh. "Experimental and Numerical evaluation of mine pillar design." Thesis, 2013. http://ethesis.nitrkl.ac.in/4937/1/109MN0504.pdf.
Full textAbstract:
Mining is an art of extracting valuable minerals or other geological materials from the earth, usually from an ore body, vein or (coal) seam with minimum unit cost within acceptable social, legal, and regulatory constraints. There are two major methods of underground mining of coal: Bord& Pillar Method and Longwall Method. Pillars are mostly encountered in the former method. Pillar is the structural element and form an integral part of a mine on which the stability of the mine depends. A pillar support is intended to control rock mass displacement right through the zone of influence of mining, while mining activities proceeds. If pillars are made too small increasing the extraction percentage, it would affect the stability of the mine and vice-versa. An economic design of a support system implies that ore committed to pillar support be minimum, while fulfilling the vital requirements of assuring the global stability of the mine structure. This project critically studies the different optimum combination of pillar dimensions that could be effectively incorporated in the mines. Geotechnical factors of a nearby underground coal mine has been determined in the laboratory. Different approaches of pillar design have been compared. Variation of safety factors with width to height ratio of pillar, extraction percentage and depth of cover has been determined and conclusion has been made. The safety and feasibility of mining method is obtained through an optimum correlation between safety factor and extraction percentage. Numerical modeling has been done to evaluate the maximum stress induced over the pillar and gallery and also to calculate the deformation in the pillar and the sagging in gallery due to induced stress. ANSYS.13 3-D software was used in numerical modeling. Different mining parameters were changed to measure the effects on stress behavior, deformation and sagging in gallery.
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Choudhary, Sundeep. "Some properties of flyash for mine backfilling." Thesis, 2013. http://ethesis.nitrkl.ac.in/5235/1/109MN0591.pdf.
Full textAbstract:
Back filling of mine voids is mandatory to avoid subsequent ground stability problems in the form of subsidence. Mill tailings and river sand are being extensively used since a long time as mine back filling materials. However strict regulation and unavailability of river sand has created a huge problem for mining industry in India. The need to develop alternative engineering material which can substitute sand has gained prominence. Large quantities of fly ash discharged from coal-fired power stations are a major problem not only in terms of scarcity of land available for its disposal, but also in psychology as well as environmental aspects. Amount of fly ash available can be recycled, mainly by adding fly ash to cement. However, the addition of fly ash to cement is limited because the production rate of cement is limited, and also the concentration of fly ash in cement is limited. In the present study three fly ash composite materials (FCMs) were developed from the fly ash obtained from a nearby captive thermal unit. The main constituent of the composite were fly ash, lime, gypsum and cement. Detailed physical and engineering properties were determined for the FCMs. Significant increases in the compressive strength were obtained after 28 days of curing time and it was observed that the fly-ash composite developed has potential to be used as substitute to sand for back filling the mine voids.
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Rai, Purna Bahadur, and Sudeep Mahapatro. "Overburden Dump Slope Stability: A Case Study At Coal Mine." Thesis, 2013. http://ethesis.nitrkl.ac.in/5434/1/109MN0590.pdf.
Full textAbstract:
Slope stability of overburden dumps plays as integral part of opencast mine project throughout the operation process. Waste dumps always have steep angled slopes as the waste has been tipped over from the top of the dump in a continuous and progressive manner. For new landfill it is often desirable to design steep slopes as it can accommodate the maximum amount of waste possible. The heavy machinery implanted for the extraction and transportation of wastes in the opencast mine whose management is of prime importance. The problems relating to overburden dump slope stability is catching attention for safe working in adverse natural constraints. This paper examines the influence of various parameters such as slope height, slope inclination, interfacial shearing resistance on the dump deposit. The analysis cover analysis of various sections of the waste dumps from the mine including material properties, strength values, bench height and angle. The evaluation of slope stability analyses in geotechnical analyses in geotechnical engineering has followed closely developments in soil and rock mechanics as a whole. Most of the design methods are purely based on field experience, followed by sound engineering judgment. During the last few decades, the concepts of slope stability analysis have emerged within the domain of rock and geotechnical engineering to address the problems of design and stability of dump slopes.
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Nayak, T. "Stability analysis of dump with admixture of fly-ash and overburden material in open-cast coal mines." Thesis, 2014. http://ethesis.nitrkl.ac.in/5952/1/e-119.pdf.
Full textAbstract:
Dump slopes with admixture of Fly-ash and overburden material for geo-mining conditions of mine A and mine B are simulated in FLAC SLOPE and OASYS software. Stability analysis of dump slope for mine B was carried out by field monitoring using total station and monitoring stations. For mine A, with addition of 15% fly-ash for a 30 m bench, the safe bench angle decreased by 20. This may be attributed to partial filling of the voids. With addition of 30% fly-ash, the safe bench angle increased by 10, which may be attributed to filling of void spaces. For the simulated conditions of 3 decks each of 30 m height, 280 angle and 40 m width of bench in mine B, the Factor of Safety (FOS) indicated through FLAC SLOPE for material with OB+25% fly-ash and layer wise dump construction are respectively 2.81 and 2.06. The difference may be because of reduction in unit weight in the former case. From the field monitoring data of Mine B dump, it is observed that the dump formed as admixture of fly ash and over burden material is stable.
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Chaudhary, A. K. "Red mud based composite material for underground coal mines roof support." Thesis, 2014. http://ethesis.nitrkl.ac.in/6064/1/E-186.pdf.
Full textAbstract:
In this thesis, several aspects of production and characterization of red mud in World and Indian context are discussed with the characterization and properties were measured through XRD, SEM analysis and pH determination.Red mud has rich in iron content especially Damanjodi, NALCO plant, Odisha as compare to the other aluminium plant in India and found that it can be used as a composite material because of its higher strength as a roof support. For further enhancement of the strength of red mud, lime is used as a binding agent in proportion with red mud. Unconfined compressive strength and Brazilian tensile strength is carried out for different composition of red mud and lime for different curing period. The red mud based composite support should take a load nearly the load taken by wooden prop in mines as a roof support. It is also economical and easier to handle.
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Panda, Debakanta, and Amit Kumar. "Determination of Some Properties of Fly Ash with Lime and Cement." Thesis, 2014. http://ethesis.nitrkl.ac.in/6053/1/110MN0032-12.pdf.
Full textAbstract:
In India the present generation of fly ash is around 150 million tonnes and utilization percentage is 55-60%. A lot of efforts and innovations are required to achieve 100% utilization. Fly ash in itself has little strength. But it gains strength in presence of additives. This investigation is an attempt to develop fly ash composite materials with lime and cement with respect to enhanced compressive strengths, tensile strengths, and shear parameters so as to evaluate the potential in geotechnical usage. Calcium carrying material as cement and lime were used as additives. Varying proportions of fly ash, lime and cement were mixed to develop the composite materials. Optimum moisture content, maximum dry density, unconfined compressive strength, Brazilian tensile strength, and shear strength parameters were determined at varying curing period. Fly ash with 5% lime was found to exhibit maximum compressive and tensile strength.
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Jaiswal, Amit Kumar. "Development of stabilized Fly Ash composite materials for Haul Road Application." Thesis, 2014. http://ethesis.nitrkl.ac.in/6138/1/212MN1465-13.pdf.
Full textAbstract:
Generation of fly ash from the thermal power stations is and will remain a major challenge for the near future. At present out of 140 MT fly ash about 50% are being gainfully used. Rest remain potential environment hazard. Filling of low lying area, underground voids are some of the potential areas of bulk uses. Sub-base of haul road is one such area. An essential attributes of such usage is the strength of fly ash at different period of time. Fly ash does not have any strength. It gains strength in presence of free lime. This investigation is an attempt in that direction. The sub-base of opencast haul road typically suffers from low bearing capacity material as the local material is used. It is envisioned that stabilised fly ash has strong potential to replace the sub-base material and provide adequate resistance to t road degradation. Lime and cement were used as additives to provide reactive lime at different proportions. Laboratory experiments were carried out to evaluate the strength gain in the fly ash. Standard proctor hammer test, unconfined compressive test, Brazilian tensile test and tri-axial test were carried out to determine respective properties. Lime and cement show to be enhancing the strength profiles of the fly ash. Curing periods also has strong influence on the fly ash strength properties. 90 % fly ash and 10% lime shows the maximum strength values at 100 days curing.
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Aggarwal, Akshay. "Evaluation Of Best-Fit Failure Criteria For Talcher Area." Thesis, 2014. http://ethesis.nitrkl.ac.in/6343/1/110MN0507-26.pdf.
Full textAbstract:
Mining sector has always been a driving force in country’s growth. Thermal energy is generated using coal as major raw material which has to be mined and handled before it could be used for power generation or in other industries. Extraction of mineral wealth from underground sources is filled with many uncertainties, rock characteristics is one of those. It is essential to predict the strength of rocks underlying and overlaying the coal so that safe mine could be designed. Various failure criteria have been developed to predict the nature of rock mass failure and its behavior. No failure criteria has been as yet designed specifically for Talcher area. Using the four existing failure criteria and six bore holes’ data, a failure criteria has been developed for Talcher area. Mohr coulomb failure criteria proves to be least acceptable to predict the behavior of Talcher rock mass. Hoek Brown failure criteria, Yudhbir failure criteria and Ramamurthy failure criteria show promising results when analyzed with the actual data. Out of the four criteria, Ramamurthy failure criteria gives the least error in actual verses predicted values. The student t test also showed that it is acceptable.
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Anand, Vishal, and Mrinal Giri. "Evaluation and Correlation of Some Properties of Coal." Thesis, 2015. http://ethesis.nitrkl.ac.in/7565/1/2015_EVALUATION__Anand.pdf.
Full textAbstract:
Mining is one of the oldest profession in world. The development and enrichment of society and mankind have experienced a direct relationship with it. The excavation of mineral resources comes with its complexities. The advancement of knowledge and technology have helped to address a lot of issues, yet many challenges remain because of the uncertainties in the earth materials. One of the major challenges is to select the right tool. Typically the selection of tools depend on the characteristics of earth materials. Rock mass is highly heterogeneous. Investigations and research in the field of rock mechanics and applied geology help in evaluating the influence of basic rock parameters such as strength, durability, crushability, etc. in effective mine designing and planning. There exists many approaches to correlate the different parameters of the rock mass so that the major influencing parameter can be predicted from a few other parameters that require relatively inexpensive processes at insitu conditions. This investigation was an attempt to determine a few strength parameters of coal and develop interrelationship among those. Coal samples from six different surface locations are collected and their unconfined compressive strength, Brazilian tensile strength, point load index, slake durability, impact strength index as well as the moisture content values have been determined at laboratory. Unconfined compressive strength of rock material is a major parameter that influence the selection of cutting tool. Correlation between these parameters are developed statistically to find the best fit equation. Applicability of a few established criteria as Broch and Franklin (1972), Bieniawski (1975), D’Andrea et al. (1964), Cargill and Shakoor (1990), Rusnak and Mark (2000), Fener et al. (2005), Kahraman et al. (2012) and Altindag and Guney (2010) have been evaluated and the predicted values were compared with those obtained by the laboratory tests.
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Sahoo, Manoranjan. "Determination and Correlation of a Few Properties of Coal." Thesis, 2015. http://ethesis.nitrkl.ac.in/7597/1/2015_BT_Determination_Manoranjan_sahoo.pdf.
Full textAbstract:
Mining activities of minerals play a very important role on the health and wealth of any nation. Though technology has reduced the adverse effects to a great extent, it is still experiencing unpredictable behaviour of rocks/coal. The cutting tools used for excavation often exhibit breakdown, high wear and tear due to change in the properties of rock/coal materials. There are many attempts to minimise these events and accurate determination of the properties is one of those. The major strength parameter is usually correlated with other parameters determined at field. The present study focuses on the study of different physical parameters of coal from regions of Talcher, IB valley and Jharkhand area. The regions are well known for huge coal mining. In coal mining operations we deal mainly with differentmechanical properties and its varying strengths since mining methods hugely depends on it. Research in geology and rock mechanics is done to elucidate the influence of the rock index properties in determining the strength, durability, crushability and nature of the rock. This project throws light on the prediction of the coal behaviour and nature of it, by finding a correlation between them. Unconfined Compressive Strength, density, Protodyakonov Strength Index and ultrasonic pulse velocity measurements are carried out and correlated with established approaches
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Kashi, Vivek Kumar. "Development and Evaluation of Fly Ash Sand Composite Materials with Additives." Thesis, 2015. http://ethesis.nitrkl.ac.in/7612/2/2015_MT_Development_Vivek_Kumar_kashi.pdf.
Full textAbstract:
The Coal production in India 2013-14 was 565.64 Million tons compared to 556.41 Million tons (MT) during the 2012-13. The coal deposit of India has high ash content of the order of 30 -45%, hence produces lot of ash when burnt. The use of fly ash has increased from 6.64 million ton in 1996-97 to a level of 99.62 million-ton in the year 2013-14. The use of fly ash is 57.63% during 2013-14. The harmless dumping of the fly ash is a major problem for the environment. Huge area required for the storage that are main challenges for sustainable development. A new invention and researches are going on for the bulk usage of fly ash. Now the use of fly ash in the bulk mode is applicable in the field of geotechnical engineering applications such that brick manufacturing, structural fills, filling of mines, production of embankments, construction of roads, haul roads etc. An effort has been made in this investigation to assess the potential utilization of fly ash composite material made by mixing of fly ash, sand, and cement or lime. In this report, a comparison study have been carried out with two additives, cement and lime in the fly ash sand mixture materials. The leading constituents of the composite are Fly Ash, Sand, and Cement or Lime. Different percentage of fly ash samples i.e. 85, 75, and 65 are taken with different percentages of cement or lime i.e. 3, 5, and 8 with sand of 12, 20 and 27% and their properties are determined. Various geotechnical experiments are carried out on the fly ash samples. Those are Brazilian Tensile Strength Test (BTS), Unconfined Compressive Strength Test (UCS), Direct Shear Strength Test (DSS) and Ultrasonic Pulse Velocity Test (UPV). These properties are determined at 0, 7, 14, 28, 56 and 90 days of curing period. Lime and cement % have maximum bearing on the fly ash composite material through with varying magnitude. Fly ash gains strength in the presence of additives
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Dash, Debadurlabha. "Influence of Chemical and Textural Characteristics on Geomechanical Properties of Sandstone." Thesis, 2015. http://ethesis.nitrkl.ac.in/7984/1/663.pdf.
Full textAbstract:
To find out the influence of chemical and petrographic characteristics on geomechanical properties of sandstone, samples are collected from mines of Mungoli Opencast Mine (Western Coalfields Limited), Lakahnpur opencast mine (Mahanadi Coalfileds Limited) and Tamnar opencast mine (Jindal Power Limited). The samples from WCL are both coarse and fine grained but the samples from MCL are coarse grained. .However medium grained sandstone, shaly sandstone and ferruginous sandstones were collected from JPL. Specimens were prepared from the samples and tested for uniaxial compressive strength (U.C.S.), point load strength (P.L.S), Brazilian tensile strength (B.T.S), dry and saturated densities, porosity. Strength has found to be increased with decrease in porosity. Mineralogy and chemical composition were found out by XRD and XRF tests respectively. Quartz and kaolinite are the dominant minerals in this study. Siderite is dominant in fine grained sandstone of JPL.Strength has found to be increased with percentage of Ca, Mg and Fe concentration. Thin sections were prepared to study the texture of the sandstone, which were then analyzed by polarized optical microscope. Petrographic properties such as packing density and packing proximity were determined which were found to affecting the strength of the strength of the sandstone. They were found to be varied from 28.2% to 86.75% and 17.23% to 74.17% respectively. A strong relationship is observed for packing proximity with the strength of the sandstone. It was found that the U.C.S of the sandstone found to be varied from 13.82 MPa to 47.4 MPa. Similarly the point load strength and Brazilian tensile strength was found to be varied from 0.36 MPa to 5.38 MPa and 0.22 MPa to 7.2 MPa respectively. Besides these the dry density, saturated density and porosity have been found to be varied from 1.85 g/cc to 2.47 g/cc and 2.02 to 2.61 g/cc respectively.
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Naidu, Basava Vishal. "Evaluation of Current Pillar Design Practice in Ramagundam Coal Belt." Thesis, 2016. http://ethesis.nitrkl.ac.in/8298/1/2016-BT-112MN0535-RAMAGUNDAM_COAL_BELT.pdf.
Full textAbstract:
Bord and Pillar mining is the oldest and most popular mining method to extract coal from underground. It is simple, easy to operate and reasonably safe. The pillars form the natural support to the overburden roof and transfer the load to floor. In the process a large portion of the coal remain blocked for long period till depillaring is carried out. The underground coal mines in India predominantly follow the Bord and Pillar method of extraction. The stability of the roof and floor depends on the stability of the pillar. The pillar stability depends on its strength, nature of coal, presence of discontinuity, method of extraction, etc. In India DGMS guidelines govern the design of pillars whereas in other parts of world the pillar design is based on strength calculation of coal and other factors. Some of the approaches are given by Bieniawski, CIMFR, Obert – Duvall, Jaiswal – Shrivastava etc. In this investigation an attempt has been made to investigate the current pillar design practice in one major coal belt of India vis-à-vis other approaches. The investigation was considered in terms of extraction percentage and safety factor for each design approaches. Pillar dimension has been optimised to determine the extraction ratio of a stable safety factor. 35 m square pillar was found to be stable with more than 2 % enhanced recovery at a depth of 270 m in comparison to the existing practice.
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Anand, Nitish. "An Evaluation of Cerchar Abrasive Index Unit." Thesis, 2017. http://ethesis.nitrkl.ac.in/9041/1/2017_MT_NAnand.pdf.
Full textAbstract:
Mining is the only source for the minerals and metals that are required to maintain the high quality of life we now enjoy in this modern, high-tech world in which we live. There are many equipment available to implement, some of them are drilling, blasting, tunnel boring and cutting machines etc. As the rock mass is heterogeneous as well as unisotropic.so the tools are most often observed to be inadequate for cutting and loosening the rock with perfection. Sccientists have developed so tests to predict rock properties and tool wear to be used to work efficiently. Tool wear is an important parameter in mechanized tunneling and is highly affected by rock abrasiveness. There are numerous tests to identify the rock abrasivity. One of the widely used rock abrasion tests is the Cerchar abrasion index (CAI). This test is used for estimation of bit life and wear in various mining and tunneling applications. The test is simple and can be considered for field applications. However, there are some discrepancies in the test results related to the equipment used, surface condition of rock samples, operator skills, and procedures used in measurement of worn out surface (wear flat). In this investigation, a Cerchar abrasivity index apparatus using mild steel material has been developed. Different parts were fabricated and a single unit was prepared. Four different sandstone samples collected from varying depth from 365m to 368m and their behavior were measured. The unconfined compressive strength (UCS) and Cerchar abrasivity index (CAI) values of these sample were determined. Compare the CAI value with standard laboratory test result. The relation between unconfined compressive strength (UCS) and Cerchar abrasivity index (CAI) values was developed. It is absorbed that the measured values compare favorably to standard laboratory test results.
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Chhimpa, Vikas Kumar. "Evaluation of Different Rock Failure Approaches." Thesis, 2017. http://ethesis.nitrkl.ac.in/9042/1/2017_MT_VKChhimpa.pdf.
Full textAbstract:
Mining and excavation activities are fraught with uncertainties and hence need accurate prediction of deferent forces that influence the design. There exist many rock failure criteria to establish mutual correlation among different force fields. But, no one is comprehensive to be accepted universally. In recent decades, several empirical criteria have been developed to estimate the failure strength of rock mass at insist conditions. The input data for the development of a failure criterion often comes from the intact rock tests. In this investigation, the intact rock recovered from bore hole logs were evaluated in terms of their different strength parameters. Seven established failure criteria as MohrCoulomb, Hoek-Brown, 1980; Bieniawski 1974 and modified by Yudhbir et al., 1983; Ramamurthy et al., 1995; Balmer and Sheorey 1989; Joseph et al., 2012; Bineshian et al., 2014 were considered to evaluate their applicability for the rock mass under study. Ramamurthy approach was observed to exhibit the best fit relation among those. The best fit criterion was adopted to develop site specific empirical non-linear relation.
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Rathore, Suryakant. "Development of Red Mud Based Composite Material to Enhance the Strength." Thesis, 2017. http://ethesis.nitrkl.ac.in/9044/1/2017_MT_SRathore.pdf.
Full textAbstract:
Red clay is a solid waste product of the Bayer process, which extracts alumina from bauxite. Red mud, as it is known by name, is brick red in colours and diluted with an average particle size of <10 µm. The red colour is caused by oxidized iron being present. India is one of the leading producers of alumina in the world. Red mud cannot be easily handled in most countries where red sludge is produced, it is kept in ponds. Red mud is alkaline in nature; hence it is dangerous for the environment. Its disposal is a worldwide problem in terms of environmental concerns. During the last decades, extensive work has been done to create various economic methods for the use of red slime by many global researchers. Some researchers tried to develop fly ash composites used to support underground roof. In order to utilize the red mud to a certain extent, the red mud-based composite material has been developed to enhance the strength and can be used in the underground mines to support the roof as the replacement of wooden props. In this dissertation, many aspects of the production and characterization of red mud in the world and Indian context have been discussed and properties are measured through XRD, SEM analysis and pH determination.
Red mud has rich in iron content especially BALCO plant, Korba as compared to other aluminium plant in India and found that it can be used as a composite material because of its higher strength as a supporting purpose in mining. For further enhancement of the strength of red mud, lime and black stone are used as a binding agent in proportion with red mud. Unconfined compressive strength and Brazilian tensile strength are carried out for different composition of red mud and lime for different curing period. It is also economical and easier to handle. In this study, we obtained compressive strength 4.7272 kg/cm2 when a load of 1.004 tonnes was applied in 28 days curing period and tensile strength 21.176 kg/cm2 was found by using composite sample (consisting of 82% red mud+10% lime+8% b.stone).
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Oram, Pradeep. "Flow Behavior of Fly Ash Slurry." Thesis, 2009. http://ethesis.nitrkl.ac.in/178/1/FULL_THESIS_10505014.PDF.
Full textAbstract:
The present study therefore makes use of literature available in terms of fly ash, to design and conduct different experiments on settling rate and hydraulic transportation aspects of fly ash.Different experiments were conducted to find the pH at different levels of lime, cement and gypsum. These were done to further utilize the cementing property of fly ash and its use for support and fill the mine voids as well as construction of cement of different strength levels. It was observed that the strength level increase with the increase in the percentage of lime and it was observed to be maximum at 4% of lime and 8 % cement and 4% gypsum. Thus as pH is directly related to strength so it indicated that the strength characteristics was further enhanced using the aforesaid composition. The SEM of the samples were done to study the characteristics of individual elements as the element having spherical shapes showed maximum pozzolanic character. The flow characters were studied using the CFD software which showed the particles flow was in turbulent manner and there is a critical velocity below which very few materials get transported and on exceeding this also the particles stick to the walls and less transportation takes place. In order to fulfill the raw data of the software experiment for moisture content, turbidity, density, and specific gravity were done. The initial model for importing into the FLUENT was done using the GAMBIT software. Thus all the relevant data like velocity, density, friction loss, particle motion etc were graphically obtained from the software and the results was analyzed.
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Singh, S. K. "Extraction of Thick Coal Seams." Thesis, 2011. http://ethesis.nitrkl.ac.in/2386/1/Snehendra-107MN023%5BFinal_Year_Project_Thesis%5D.pdf.
Full textAbstract:
This project presents numerical model studies on stress analysis during depillaring of 5-11m thick coal seams at depth range of 150-900m at an interval of 150m. Finite Difference Code – FLAC (fast Legrangian analysis for continua) was used for understanding the influence of depth and thickness of coal seams on stress distribution over pillars, stooks and ribs at development stage and depillaring stage through parametric studies. 24 numerical models with different configuration representing the parameters in field experimental trials are used. Variables of the parametric studies for stress analysis are: seam thickness in the range of 5 – 11 m at an interval of 2 m and depth cover of 150 m to 900 m at an interval of 150 m.The maximum on pillar was found to be 35 MPa at 900m depth in 5m thick seam and the minimum was 5 MPa at 150 m depth. The maximum stress on stooks and ribs was found to be 70 MPa and 10 MPa in 5 m, 7 m at 900 m and 450 m depth respectively.
From model it was found that thickness of the seam does not have any effect on the stress behaviour of the pillars after development work. Parametric studies through the numerical models indicated decreased vertical stress over the stooks with increasing height of the extraction at the depth covers in the range of 150-900 m. Though the stress coming was less, the stooks were getting yielded very soon due to increase in height of the stook and increase in height to width ratio.
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Gaurav, Anubhav. "Extraction of contiguous coal seams." Thesis, 2011. http://ethesis.nitrkl.ac.in/2495/2/Anubhav_107mn007.pdf.
Full textAbstract:
Underground mining methods are still used to excavate large proportions of coal in India. This accounts for up to 70 % of the total coal produced. The opencast is only profitable up to a certain depth; below that underground mining is the only profitable alternative. So more effective underground mining methods are required to be searched for and presented. When two seams are above one another, the workings in one tend to affect the working in another. In India coal seams that are near to one another such that the parting thickness between them is below 9 m are called contiguous. Coal mine regulation number 104 of Coal Mine Regulations, 1957 apply to such seams. The objective of this project was to evaluate the effect of parting thickness and depth cover of coal seams on stress distribution over pillars, stooks and ribs at different stages of depillaring, through numerical modelling using FLAC 2D software. Contagious seams can be extracted in three possible ways, viz, First extraction in the upper seam then followed by the lower seam, first extraction in the lower seam then followed by extraction in upper seam or simultaneous extraction of both the seams. In India such seams are extracted preferably by caving or stowing. For such seams when extracted the pillars of one seam shall be vertically above or bellow the pillars of other seam. In the example taken under consideration in this project, the two seams contiguous to one another were generated. Their depth cover (from 150 m to 750 m) and parting thickness (from 3 m to 9 m) were varied and the stress distribution over pillars, stooks, ribs and parting were evaluated. The evaluation was carried at two stages of mining, i.e. at development stage and after extraction of two and a half pillars with a single rib left. The maximum stress in the pillar increased with increase in parting thickness and depth cover. For stooks change in parting thickness was found to have no effects, while it increased with increase in depth cover. Maximum stress in ribs were found to be increasing with increase in parting thickness for top seam but remained more or less constant for bottom seam. While with increase in depth cover the maximum stress was found to be increasing first then decreasing. It can be inferred that the ribs may have yielded for larger depths.
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Pati, Nishant Kumar. "Evaluation of Underground Coal Pillar Design." Thesis, 2011. http://ethesis.nitrkl.ac.in/2510/1/107MN015.pdf.
Full textAbstract:
Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an ore body, vein or (coal) seam. Mining involves different processes like prospecting for ore bodies, analysing the feasibility of extraction, profitability of the operation, extraction of the desired materials. One of such methods is the Bord and Pillar method of mining which is one of the oldest methods of mining. The success of Bord and Pillar mining is selecting the optimum pillar size. If the pillars are too large, then the extraction ratio decreases leading to less profitability and if the pillars are too small it endangers the overall mine safety. Indian mines have about 60 % of the coal blocked in the form of pillars. This investigation critically reviews the different practices of pillar design followed around the world in general and evaluates the existing practices of an Indian mine in particular. Geotechnical factors of a nearby underground coal mine has been determined in the laboratory. Different approaches of pillar design have been compared. Variation of safety factor with width to height ratio of pillar, extraction percentage and depth of cover has been determined and conclusion has been made. The safety and feasibility of mining method is obtained through an optimum correlation between safety factor and extraction percentage.
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Singh, Vikrant Dev. "Design of systematic support system for development and depillaring in underground coal mines." Thesis, 2013. http://ethesis.nitrkl.ac.in/4831/1/109MN0016.pdf.
Full textAbstract:
Bord and pillar method is the most widely practiced underground mining method in India. Nevertheless about 61% of underground coal mining accidents are due to roof and side fall of bord and pillar. Design of systematic support is essential to avoid strata control problem and to provide safe working condition. Three distinct methodologies; empirical approach, numerical modeling and field monitoring were followed and compared in the project to provide a comprehensive design of systematic support. A case study of 1AS2 panel of RK-6 Incline, SCCL is chosen for the design of systematic support. The empirical design of support is developed using RMR and Q-system and validated with numerical modeling and field monitoring. The systematic support developed by RMR with factor of safety greater than 2 for the gallery was 1.5 m spacing of 1.8 m full column grouted bolts with spacing of 1.4 m between rows. Junction support was 33% extra full column grouted bolts. Systematic support designed for slices and goaf edges with Q-System was skin to skin chocks with corner props and breaker line bolt with 1 m spacing. Maximum convergence measured with telescopic convergence rod in the field at the station 6F- 57LS was 48 mm. Maximum deformations observed by numerical modeling in the gallery was 58 mm. The numerical model was almost validated with the field monitoring data with 17% approximation, thus the numerical model can be used for prediction of strata behavior of future working.
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Prasad, B. N. V. Siva. "Study of Strata Behaviour in Blasting Gallery Panel in Coal Mines." Thesis, 2013. http://ethesis.nitrkl.ac.in/5142/1/109MN0505.pdf.
Full textAbstract:
In mining industry, the challenging task of a mining professional comprises of the extraction of maximum natural resources with utmost safety of the miners. ¡§Blasting Gallery¡¨ method is a unique technique of depillaring thick seams for higher recovery of coal. The present study has been aimed to examine thoroughly BG method operational systems in Indian geo-mining conditions such as: „« Study of roof convergence with respect to face advancement during different stages of extraction of coal in Blasting Gallery panels in SCCL mines. „« Simulation of field conditions in the numerical model generated using FLAC. „« Interpretation of strata behaviour through numerical modeling using FLAC. For this purpose, BG panel of GDK 10 incline, Singareni Collieries Company Limited (SCCL) was selected. This mine has a thick coal seam of 11m, at a depth of 350mtr. Convergence behaviour with respect to goaf edge distance (GED) was monitored with the help of high state-of-the-art equipment throughout the life of BG panel. The coal sample was collected from the mine and tested for determination of the rock mass parameters. The geotechnical conditions of the mine were simulated through Numerical Modelling by FLAC. The results obtained from the FLAC were compared to field data so that the validation would represent the system in totality. The different conclusions drawn from this work is enumerated as follows: „« The maximum rate of convergence and cum. convergence recorded in field was 4mm/day and 61mm respectively, measured at station C-5 in 68 Level. „« From the triaxial testing, the major principal stresses of 22, 32 and 41.5 MPa were obtained at confining stresses of 0, 2 and 3 MPa respectively. „« The results obtained from the RocLab software indicated the Cohesion, Friction Angle, UCS and Tensile Strength values to be 1.1MPa, 30.840, 1.314 MPa and 0.32MPa respectively. „« The model predicted maximum cumulative convergence to be 70mm while that observed in field is 61mm.
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Prakash, Bisleshana Brahma. "Design of Stable Slope for Opencast Mines." Thesis, 2009. http://ethesis.nitrkl.ac.in/1333/1/10505020.PDF.
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Slope stability analysis forms an integral part of the opencast mining operations during the life cycle of the project. In Indian mining conditions, slope design guidelines were not yet formulated for different types of mining practices and there is a growing need to develop such guidelines for maintaining safety and productivity. Till date, most of the design methods are purely based on field experience, rules of thumb followed by sound engineering judgment. During the last four decades, the concepts of slope stability analysis have emerged within the domain of rock engineering to address the problems of design and stability of excavated slopes. The basic objective of the project is primarily addressed towards: a) Understanding the different types and modes of slope failures b) Designs of stable slopes for opencast mines using numerical models. Analyses were conducted using the finite difference code FLAC/Slope. The work was aimed at investigating failure mechanisms in more detail, at the same time developing the modeling technique for pit slopes. The results showed that it was possible to simulate several failure mechanisms, in particular circular shear and toppling failure, using numerical modeling. The modeling results enabled description of the different phases of slope failures (initiation and propagation). Failures initiated in some form at the toe of the slope, but the process leading up to total collapse was complex, involving successive redistribution of stress and accumulation of strain. Significant displacements resulted before the failure had been developed fully. Based on parametric studies it can be concluded that friction angle plays a major role on slope stability in comparison to Cohesion.
Keywords: Slope stability, open pit mining, numerical modeling, rock mass strength, failure mechanisms.
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Chakravarty, Raj. "Study of Stability of Overburden Dumps Mixed with Flyash in an Opencast Coal Mine." Thesis, 2013. http://ethesis.nitrkl.ac.in/5145/1/109MN0106.pdf.
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The huge quantities of fly ash generated in India (131.09 mn tonnes in 2010-11) by the coal fired thermal power plants every year raises a serious question about its disposal along with the difficult issues of land availability and pollution of local environment. According to MoEF guidelines any mine within 50 km from a power plant has to use at least 25% of its backfill as fly ash. In this project the stability of overburden dumps mixed with fly ash in KTK opencast mine of SCCL has been studied. Samples of overburden and fly ash were collected from KTK mine and APGENCO, Chelpur respectively. Different geo-technical parameters i.e. density, cohesion and friction angle of OB mixed with 15% and 30% fly ash were found out. Using those parameters, dumps of 30 m height were modelled in FLAC SLOPE software to find out the safe slope angle i.e. angles for which the factor of safety is greater than 1.2. The following results were obtained for different mixes of fly ash and OB: Soil Angle FoS OB 29 1.22 OB + 15% fly ash 26 1.22 OB + 30% fly ash 28 1.22 The initial decrease in slope angle from 29º to 26º with the addition of 15% flyash might be attributed to the inadequate packing of voids between OB particles by the finer sized flyash particles With increasing quantity of flyash i.e. at 30%, packing of the voids would become more compact as they reduce the void ratio. This would lead to the increase in slope angle obtained with OB + 30% fly ash from 26 º to 28º. However, there was no significant change in slope angle with addition of flyash vis-à-vis OB.
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Ram, Pankajkumar Kanchan. "Development of a Needle Penetrometer Device and Evaluation of its Performance." Thesis, 2016. http://ethesis.nitrkl.ac.in/9286/1/2016_MT_PKRam.pdf.
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Mining and excavation activities involve dealing with earth materials typically rock mass of varying properties. The mechanical properties of rocks play major in successful excavation process. However the determination of correct strength values is a challenge as rock properties vary widely. Obtaining the right sizes for strength test are very difficult due to structural variation. Innumerable attempts have been made to predict rock properties. Needle penetrometer is one such unit developed to predict compressive strength of rock from the surface testing. It measures the surface behavior and correleate the same with the compressive strength parameter. In this investigation a needle penetrometer using mild steel material has been developed as per the ISRM (2014) suggested guidelines. Different parts were fabricated and one unit was prepared. Five different coal samples collected from varying depth from 480 m to 580m and their behavior were measured. Both th unconfined compressive strength and needle penetration index values of these sample were determined. Six established approaches Ulusay and Erguler (2012), Aydan (2012), Uchida et al. (2004), Okada et al. (1985) and Takahashi et al. (1988) and Yamaguchi et al. (1997) were compared with the measured results. It was observed that the measured values compared favourably with that of Okada et al. (1985)
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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)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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Rajput, Ashish. "A Study of Energy in Rock Blasting." Thesis, 2016. http://ethesis.nitrkl.ac.in/8118/1/2016_MT_711MN1088_Study_of_energy.pdf.
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Creation impacts have been observed in quarry so as to evaluate the quantifiable structures of energy in which the energy conveyed by the unstable is changed in rock impacting. The seismic field from Minimate readings, the introductory speed of the impacted rock face acquired utilizing Gurney condition, and the section size disseminations from picture investigation of the muckpile material are utilized to decide the seismic wave energy, the Kinetic energy and the Fragmentation energy, individually, moved in the impacting procedure. The impacting information and the techniques for figuring of the energy terms from those are depicted in subtle element. The most extreme aggregate energy measured records for not more than 26% of the accessible dangerous energy in the event that this is appraised as the warmth of blast, however lower figures are normally acquired. Sample of iron ore collected for laboratory experiment to find out the fragmentation energy with the help of “WipFarg Software (used for sieving of different rock sizes)”, drilling and blasting data, average size of fine and coarser particles, data for ppv to find out seismic energy, also Gurney equation for calculation of kinetic energy The energy discharged by the explosive, borne in the detonation endless supply of the chemical reaction, is changed over into heat and work to the surroundings as indicated by the first principle of thermodynamics.
Some of these structures get to be obvious amid the impact, to be specific:
• the fracture work, that eventually shows up as new surface in the rock fragments;
• the work exchanged as shock wave into the rock, that proliferates as plastic and at last elastic waves, showing up as seismic wave or ground vibration; and
• the work to uproot the rock and shape the muckpile, that shows up as kinetic energy conferred to the rock.
Other energy exchange happens, in a less evident manner, as takes after:
• expansion work of the fractures, that is consumed as elastic and plastic miss happening of the rock in the surface of the fractures as they are infiltrated by the gasses;
• heat exchanged to the rock from the hot detonation items; and
• heat and work passed on as enthalpy of the gasses venting to the air through open fractures and stemming.
The energetic analysis provides a good insight of the explosive/rock interaction and a better understanding of the blasting process, encompassing a broad range of scientifically challenging subjects .For each energy component, first of all some experiments have been carried out in laboratory and some data collected from Iron Ore Mine to find out some results for different energy. Then with the help of some software and some equations from literature helped me to do my project work with efficiency. Energies ratios with respect to the total explosive energy are: Fragmentation energy is 31.45%, seismic energy is 1.69%, kinetic energy 13.599%. Total explosive energy measured is equal to 2.434 GJ
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Mohanty, Manasi Manjari. "Numerical Simulation of CO2 Sequestration to Enhance Methane Recovery using Multipoint Geostatistics." Thesis, 2018. http://ethesis.nitrkl.ac.in/9813/1/2018_PhD_MMMohanty_510MN101_Numerical.pdf.
Full textAbstract:
Coal beds are extremely complicated porous medium with characteristics of heterogeneity, dual porosity and stress sensitivity. In the past decades, great achievements have been made to the simulation models of pressure depletion coal bed methane (CBM) recovery process and CO2 sequestration and enhanced coal bed methane (ECBM) recovery process. However, some important mechanisms are still not properly included. Among them, the most important is the influence of geo-mechanics. Due to its influence on the coal bed permeability, being the key parameter for the success of methane recovery process, changes drastically with alterations of in situ stresses and strains. In present reservoir simulators, the change of coal bed permeability is estimated with analytical models. Due to the assumptions and over simplifications analytical models have their limitations or problems in application.
In this research, in order to properly estimate the changes of permeability and porosity in the simulation of CO2 sequestration and ECBM recovery process, comprehensive permeability and porosity models have been developed with minimum assumptions and corresponding established simulation methods. Firstly, a set of porosity and permeability modeling using multipoint statistics simulation procedure is followed and application to these models in reservoir simulations is proposed. Using the models and simulation procedure, a sensitivity study mainly on the parameters related to change in coal bed permeability and deformation has been made for the CBM recovery process. On this basis of understanding, simulation of 2 phases flow (CO2 & CH4) for improving methane recovery is done by COMSOL software.
At last the porosity and permeability models and the simulation procedure are successfully applied. Simulation is completed by using Principal Component Analysis (PCA) and CO2 sequestration by using COMSOL software.
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Suman, Sandeep. "Slope Stability Analysis Using Numerical Modelling." Thesis, 2015. http://ethesis.nitrkl.ac.in/7065/1/Slope_Suman_2015.pdf.
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Stability analysis of slopes is a very important component of various opencast mining projects throughout the life cycle of the project. A failure of slope in the area being worked in a mine can lead to some severe social, economic as well as a great safety catastrophe. The basic failure conditions are very diverse & complicated. These failure mechanisms are greatly dependent on local geology, which are pretty unique to a specific location of the rock mass. In the recent years too, the method of designing slopes are completely based upon the field knowledge. Better approach can be made through safe designing of slopes. The aim of the project is to carry out numerical modelling for slopes having various dimensions and different rock properties. The numerical modelling is carried out using FLAC SLOPE for finding out the factor of safety. The parameters are varied for each slope and the factor of safety calculated for each step. These values are correlated with the bench parameters to find out how the factor of safety changes with changing parameters.
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Goswami, Agam Das. "An Evaluation of Multi-point Stochastic approaches for Uncertainty Assessment in Ore Grade Estimation." Thesis, 2018. http://ethesis.nitrkl.ac.in/10028/1/2018_PhD_ADGoswami_512MN1005_An_Evaluation.pdf.
Full textAbstract:
Minerals and energy resources are the lifelines for the development and prosperity of a nation. In India, majority of the deposits are lying deep in earth, and it throws challenges to mining, engineers, and geologist to extract them safely and economically without compromising the environment. Ore grade estimation is one of the vital stages of each and every mining project. It plays the dominant role in the decision-making process for investment and development of various mining projects and hence become an important and crucial stage. The thesis focuses on the development of machine learning (ML) based non-linear regression models and pattern based multipoint stochastic (MPS) simulation algorithm for uncertainty assessment in ore grade estimation. In this thesis ML-based estimators and pattern based MPS simulation were developed and subsequently applied to two case study mines (a limestone and an iron ore deposit) in the Indian scenario.
Distinct ML based nonlinear regression architectures such as Multilayer Perceptron Neural Network (MLP NN), General Regression Neural Network (GRNN), Support Vector Regression (SVR) are developed to improve the grade estimation. The multiple lithological units are incorporated as auxiliary information with spatial coordinates into the ML-based models. These models do not require any preliminary geological study and are free from any statistical assumption on the raw data.
For iron ore deposit, set of input variable consists of three-dimensional (3-D) spatial coordinates and their ten underlying lithologies, and an iron grade is the only output variable. However, for limestone deposit 3-D spatial coordinates with four distinct lithology form the set of input variables. The set of output variables consists of four constituents of limestone deposit as calcium oxide (CaO), alumina (AI2O3), ferrous oxide (Fe2O3), and silica (SiO2). The ML architectures with appropriate training capture the inherent spatial variability of assay values and their underlying rock types. The best design with the lowest root mean square error (RMSE) and the highest correlation coefficient (R) is selected for the construction of grade map. The GRNN network was found to be more suitable as compared to all other models regarding generalization capability for both limestone and iron ore deposit. The dissertation also aims at developing pattern based multipoint stochastic simulation algorithm using contourlet transformation named as contoursim for uncertainty assessment in grade estimation. The idea of contoursim is motivated by the wavesim existing in the recent literatures.
The algorithm is developed for the simulation of spatially correlated variables such as ore grade and their underlying lithology. The major steps involved in the contoursim is same as that of other MPS based scheme, but the use of separable filter bank structure allows them to identify the complex structure such as curve linearity present in the geological deposit. The CT with their separated filter bank structure capture the complex spatial interaction among several attributes with sparse coefficients. In this thesis, dimension reduction of the pattern database is achieved by contourlet decomposition of each pattern with appropriate scale. The reduced pattern database is further classified into several clusters by coarsest scale coefficients. The algorithm captures the existing trend and continuity of the ore deposit and thus reproduced the available intrinsic patterns of the training image into their several realizations. Multiple realizations of the iron and limestone allow for an assessment of spatial uncertainty in grade estimation. Further ensemble map of ten different realizations have been obtained. The histogram of the training image and their realizations also confirms the capability of contourlet transform to capture the spatial heterogeneity and anisotropy inherent in the complex geological phenomena.
The algorithm is verified by two dimensional unconditional simulation using categorical binary channel training image and continuous mineralization of CaO. The sensitivity analysis of the algorithm with respect to its several influential parameters is explored. The study revealed that the algorithm is sensitive to the number of clusters, number of contourlet coefficients, and number of directional sub-bands from coarser to fine level of decomposition.
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Vatcher, Jessica Lauren. "Architecture of a Classification System to Evaluate Fault Slip Risk in a Mining Environment." Thesis, 2012. http://hdl.handle.net/1974/7237.
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As the depth of mining increases, so does the risk of fault slip related rockbursts. Currently, there is no way to evaluate this risk, however the need for such a system is clear. Fault behaviour in mining environments is the result of a complex interaction between the mining system and the geological system. Although numerous models exist, the wide spectrum of fault behaviour cannot be fully explained. Additionally, these models are phenomenological, resulting in a disconnect between observable parameters and the models of faults. Fault behaviour is dependent upon the strength of the fault, the stresses acting along the fault, the boundary conditions and fault-system stiffness. Significant work exists in the field of earth science attempting to relate properties of the geological system to fault behaviour. In mining environments, these relationships become increasingly difficult to determine due to the time variable nature of mining activities. In order of importance, the following factors influence fault behaviour: excavations, tectonic history and in situ stress, fault system, fault zone geometry, pore pressure, fault zone slip surface and core, blasting, fault zone damage zone and wall rock and temperature.
Numerical stress analysis models were created to evaluate the influence of excavations, tectonic history and in situ stress and the fault system on fault behaviour. Excavations were placed in various locations in a fault system. Results showed that there was no clear relationship between excavation location and fault behaviour; small perturbations in the initial state caused significantly different outcomes.
The architectures of many classification and decision support systems were evaluated for purposes of a fault slip classification system. Due to the chaotic nature of fault behaviour and the time variable nature of the factors that influence fault slip, a typical classification system is not an appropriate architecture. Instead, it is recommended that a fault slip risk identification system be created, allowing for the incorporation of historical and live data to create a real time response. Artificial neural networks, numerical stress analysis, data from the identified important factors, and seismic data is recommended to form the basis of the fault slip risk identification system.Thesis (Master, Mining Engineering) -- Queen's University, 2012-06-01 13:17:08.453
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Gu, Fagang. "Reservoir and geomechanical coupled simulation of CO₂ sequestration and enhanced coalbed methane recovery." 2009. http://hdl.handle.net/10048/810.
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Thesis (Ph.D.)--University of Alberta, 2009.Title from PDF file main screen (viewed on Apr. 1, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geotechnical Engineering, [Department of] Civil and Environmental Engineering, University of Alberta. Includes bibliographical references.
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Spearing, Anthony John Spencer. "A stoping method and support systems for tabular mining at ultra-depth on the Witwatersrand basin." Rozprawa doktorska, 1992. https://repolis.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=3292.
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Spearing, Anthony John Spencer. "A stoping method and support systems for tabular mining at ultra-depth on the Witwatersrand basin." Rozprawa doktorska, 1992. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=3292.
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