Stability Analysis of Underground Mining and their Application on the Mine Chaabte El Hamra, Algeria (original) (raw)
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Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, 2019
Purpose. Analysis of the current and proposed room and pillar exploitation technique of the Zinc mine (Chaabet ElHamra) by two different approaches, the tributary area (TAM) for analytical method and numerical method (Fi nite Element Method FEM) through PLAXIS 3D software. methodology. In this work, the stability analysis of the roomandpillar of the Chaabet ElHamra mine was per formed. Firstly, the safety factor for both conditions was calculated by TAM: 1) the current operation using 8.0 m wide rooms with 4.0 × 4.0 m pillar sections; 2) the proposed technique using 9.0 m wide rooms with 3.0 × 3.0 m pillar sections. Secondly, the numerical method was used to analyze pillar stability and total displacement of the proposed technique through the PLAXIS 3D software. findings. Using more than one method in underground mining for analysis of the existing or proposed technique is the best solutions for achieving reliable results. originality. The originality of this work is to use two diff...
Geotechnical and Geological Engineering, 2020
Underground mining continues to progress to difficult, complex and deeper levels in order to tackle ascending demand of minerals. These deep mining occurs in a very hard conditions, in which right practice must be implemented in order to overcome the technical and safety challenges and reap economic gains. The redistributed stresses, large deformations and creeping behavior in such environments worried engineers and geoscientific researchers. The working technic in Boukhadra iron mine is based on the sublevels slaughtered, with room, pillar workings and roof behaviour. Based on rock mechanics and geotechnical engineering methods, our research adopted geo-mechanical and numerical approaches to predict the rock mass behaviour in Boukhadra underground mine and to deal its stability problem. The results show that plastic deformations and stress points increasingly in pillars. In zones with low cover, the tensile zones develop at the roof, leading to a progressive rupture giving rise to a droop. In some areas, fractures develop in a rather remarkable way; in this case the breaking of the pillars and collapse can occur generalized and brutal. The stability of roomand-pillar mines does not depend only pillars. It involves the determination of critical factors and limits of mining. Our study demonstrates that the use of scientific and technical achievements, have become a necessity in mining.
Mining Revue, 2021
The underground mining of the rock salt deposit from Slănic started over 350 years ago, in bell-shape room (Ocna din Deal and Ocna din Vale) and in large trapezoidal rooms (Carol, Mihai and Unirea mines), until 1970, generating a volume of underground excavations of over 5.3 million m3. Over time, these large excavations have lost their stability (collapse of the mines to the surface and various degrees of instability of the Carol and Mihai mines), keeping only the Unirea mine in operation for tourist purposes. This article is a synthesis of the analysis with 3D finite elements, in elasto-plasticity, of the state of stress and strain developed around the excavations and highlighting the factors that led to the loss of their stability, focusing on the Unirea mine.
Numerical study on deformation around underground mining structures (Algeria)
Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu
Purpose. To study the stability of underground mining structures using numerical method based on finite elements, two-dimensional (2D), Finite Element (FE) modeling using GEO5 calculation model. Methodology. To consider the influence of geotechnical parameters, the tunneling is carried out by the NATM method. In order to check settlements in soft ground and to carry out the work in complete safety, we used software based on the finite element method. Findings. Determination of the range and prediction of subsoil displacements are necessary when designing this type of structure due to the need to ensure the safety of the active environment located in the zone of influence. Originality. The originality of this work is the characterization of the soil of the studied region, determining of the different physical and mechanical properties as well as the modeling with a recent calculation model based on the Mohr-Coulomb behavior mode. Practical value. Given the characteristics of the curr...
Mining of Mineral Deposits, 2019
Purpose. The analysis of the current underground mine workings, both those that are in operation and works located within the mining perimeters where activity was stopped, is leading directly to the problem of stability, i.e. safety. The aim of the paper is the stability analysis of underground workings located in strongly metamorphosed andesite and determination of mine pressure in the context of rock-support system interaction was made based on numerical methods, taking into account the effects of inhomogeneous stresses, anisotropy of rocks, and time. Methods. Numerical-based finite element method was applied to obtain the stress variation radial displacement and mine pressure epures for the analyzed mine workings. To assess the stability of underground mine workings, a mathematical model was developed based on the principle of proper conformity and safety level, according to the main factors that influence the stability of underground workings. Findings. The results obtained showed that underground workings analyzed are characterized by a low stability level, which is consistent with the results obtained by the observations and numerical method. Depending on the computed level of safety has been established correspondence to class stability of underground mine workings. The results are confirmed by in situ observations and solutions obtained by experiments. Originality. The patterns of the stress-strain state change in the context of rock-support system interaction for horizontal galleries located in strongly metamorphosed andesite. Practical implications. The research results will facilitate to improve stability of mine workings and to significantly increase the safety level throughout their entire life-cycle.
Journal of Mines, Metals and Fuels
The major coal producing companies of the India are running most of the opencast mines to excavate the underground developed pillars as the underground mines possess various strata control issues, subsidence, ensures low production and makes losses. During extraction of such developed pillars, the men and machineries may trap in the developed galleries. Hence, the conditions of the pillars and galleries need to be assessed before approaching the developed pillars. In this study, a case study of Jharia Coal field is chosen for detailed stability analysis of the workings. For this, 3D numerical modelling technique is applied to assess the condition of the underground pillars and galleries. From the study, it is observed that the pillars and galleries of the workings for a maximum of 15 m from the slope surface fails severely. It is therefore, these area requires special precautions while approaching the developed coal seam/workings.
Selection of new appropriate mining method: case of Boukhadra iron ore mine, NE Algeria
Arabian Journal of Geosciences, 2019
The selection of the adequate mining method is the cornerstone for mine planning and design. This selection depends on geological, geotechnical, economical, and environmental parameters. This paper's main purpose is to select the most appropriate mining method for the south body of Boukhadra underground mine (NE Algeria). To do so, a new study is needed taking into account the lithofacies variation between different stages (levels) of exploitation, and British Columbia University (UBC) method is practical here. The results have shown that the cut and fill, sublevel stoping, sublevel caving, and block caving methods are technically feasible. However, the economic and environmental parameters have favored the sublevel stoping method. This method was subjected to a stope resizing analysis using the stability graph empirical method. The finite element calculation code Plaxis 2D and 3D was used in order to validate the results of the empirical method.
Stability analysis of underground mining openings with complex geometry
Studia Geotechnica et Mechanica, 2016
Stability of mining openings requires consideration of a number of factors, such as: geological structure, the geometry of the underground mining workings, mechanical properties of the rock mass, changes in stress caused by the influence of neighbouring workings. Long-term prediction and estimation of workings state can be analysed with the use of numerical methods. Application of 3D numerical modelling in stability estimation of workings with complex geometry was described with the example of Crystal Caves in Wieliczka Salt Mine. Preservation of the Crystal Caves reserve is particularly important in view of their unique character and the protection of adjacent galleries which are a part of tourist attraction included in UNESCO list. A detailed 3D model of Crystal Caves and neighbouring workings was built. Application of FLAC3D modelling techniques enabled indication of the areas which are in danger of stability loss. Moreover, the area in which protective actions should be taken as...
PRELIMINARY SUPPORT DESIGN FOR UNDERGROUND MINE ADIT, ARTANA MINE, KOSOVO
2021
In this paper, preliminary support design of the main underground opening (i.e., mine adit) located at the Artana lead-zinc mine, Kosovo, was examined by employing both conventional and numerical methods for safe underground excavation and design. In order to conduct field studies including discontinuity surveying and sampling for laboratory testing two empirical methods, namely rock mass rating (RMR) and geological strength index (GSI) were employed. For the purpose of determining necessary support units RMR system was utilized. However, these kind of systems can take into account for neither the depth of underground opening nor in situ field stresses. For this reason, empirical design methods (i.e., RMR system) failed to investigate the performance of rock support units; therefore, a 2D finite element analysis program was used to assess the performance of the proposed support systems. This indicated that RMR system might not be applicable for poor and very poor rock masses located in deep environment (i.e., 300 and 400 m). Moreover, this is linked to the fact that the RMR system does not consider in situ stress conditions. This study showed that when empirical methods are supported by numerical analysis, the preliminary support system design will be much more reliable.
REM - International Engineering Journal, 2019
The design of room-and-pillar mines relies on the correct estimation of the safety indicator of the underground structures formed by the excavation of drifts. Thus, the study of the geomechanical behavior is of vital importance. The mathematical models play an important role in the identification of problematic areas and allows different configurations to be tested in a safe manner. This article presents the development and application of a flexible and automatic routine to quantify the safety of room-and-pillar mines in terms of the safety factor of pillar and room convergence. The commercial software package FLAC3D was used to implement a computation routine in FISH language that can automatically represent the main characteristics of the geomechanical conditions, lithology and geometric features of a room-and-pillar project in a fast and accurate manner. A case study was performed on a manganese ore mine in order to demonstrate the capabilities of the developed routine.