Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
6 results
Search Results
Item A machine learning framework for predicting elastic properties of sedimentary rocks from ball mill grinding characteristics data(CRC Press/Balkema, 2024) Swamy, S.V.; Harish, P.; Kunar, B.M.; Chandar, K.R.Elastic properties of rocks like Young’s modulus and compressional P-wave velocity are vital for understanding their stress-strain response in mining and rock engineering applications. Traditional methods for determining these properties involve labor-intensive, expensive and time-consuming. To address these challenges, this study proposes a novel predictive method. It utilizes a multi-layer perceptron feed forward neural network (MLP-FFNN) trained on grinding characteristics of ball mill to predict Young’s modulus and compressional Pwave velocity in sedimentary rocks. Laboratory experiments on limestone and dolomite samples generated extensive data, enabling development of prediction models using the proposed MLPFFNN. The developed models demonstrate high predictive accuracy (R values: 0.952 for E, 0.987 for Vp) in training and good generalization (0.866 for E, 0.9707 for Vp) in testing, along with low Root Mean Squared Error (RMSE) values. These findings underscore the efficacy of neural network models in predicting E and Vp from grinding characteristics of ball mill. © 2024 The Author(s).Item Effect of longwall workings on the stability of overburden dumps(CRC Press/Balkema, 2024) Harish, P.; Swamy, S.V.; Chandar, K.R.Extraction of coal is done in both opencast and underground methods. Opencast mining generates a huge amount of overburden while excavating the coal. Managing the overburden material, deposited as dumps at considerable heights to minimize ground coverage, is crucial in opencast mines, but it poses risks such as potential failures. Such failures can stop the mining activities, endanger personnel safety, and damage equipment. At times, limitations in space, the placement of overburden dumps over underground excavations, posing stability challenges due to pre-existing stresses from activities below the surface. This paper explores the stability prediction of overburden dumps above longwall workings, using Rocscience RS2 v19.2, a two-dimensional finite element analysis software. Strength Reduction Technique determines the factor of safety (FOS), revealing that the presence of underground longwall excavation induces a vertical deformation of 56.4mm for the critical strength reduction factor of 1.12, emphasizing the impact on overburden dump stability. © 2024 The Author(s).Item A review on stability analysis of coal mine dumps(Inderscience Publishers, 2024) Harish, P.; Chandar, K.R.Opencast mines are increasingly extracting deeper coal seams in large quantities, leading to a rise in mine depth and generation of substantial waste. Disposal of this waste becomes challenging due to the need for additional land, resulting in dumping excess waste on existing dumps, posing risks of dump failure, property damage, and loss of life. This paper aims the critical review of the stability of dump slope structures that are present on the weak or disturbed foundations which further leads the dumps to fail. Many researchers have concentrated on the irregular base, loose material presence in the foundation, sloping floors, improper compaction at the foundation level, presence of black cotton soil, etc., stating load of the dumps over the weaker foundations exerts more pressure on the foundation and causing the dumps to fail. It synthesises key findings on stability analysis approaches, design criteria, optimisation techniques, and critical parameters involved in numerical modelling-based design for secure dump slope structures. © © 2024 Inderscience Enterprises Ltd.Item Stability Analysis of Overburden Dumps over Old Underground Workings Using Artificial Neural Networks(Pleiades Publishing, 2024) Harish, P.; Chandar, K.R.Abstract: Stability of overburden dump slopes is a crucial aspect in designing secure and cost-effective dumps. The Strength Reduction Factor (SRF) serves as a widely used term to assess dump stability. This paper focuses on developing an Artificial Neural Network (ANN) model capable of predicting SRF for overburden dumps situated above existing underground workings. To construct the model, a dataset comprising 96 numerical simulations of overburden dumps generated through the finite element method was utilized. A neural network architecture with three layers of forward-backward propagation was utilized, containing hidden neurons to analyze simulations during training, validation and testing stages. The input parameters for studying overburden dump slopes over underground workings included dump slope height (Sh), dump slope angle (), cohesion (C), friction angle (Ø), unit weight () of the dump material, depth of working from the surface (D), centre-to-centre pillar distance in underground workings (C-C), and gallery width (Gw). The ANN predicted results were compared with the outcomes derived from numerical simulations of overburden dump slopes above underground workings. The study highlights that the developed ANN model in this research proves highly effective in handling and designing complex overburden dump slopes. The obtained results indicate a Mean Square Error (MSE) of 0.0595 and a coefficient of determination (R) of 0.883, both of which are considered acceptable. © Pleiades Publishing, Ltd. 2024.Item Influence of Underground Workings and Dump Height on the Stability of Overburden Dumps(World Researchers Associations, 2025) Harish, P.; Satyanarayana, I.; Chandar, K.R.Coal is extracted using both underground and opencast methods of working. During the coal extraction process, opencast mining produces a significant amount of overburden. In opencast mines, the removed overburden material is dumped at significant heights to reduce ground coverage. But overburden dumps with great heights are at risk and sometimes lead to failure of dumps causing loss of men and machinery. Stability issues will become more complicated when the overburden is dumped above the old underground workings. Complication arises because of redistribution of pre-existing stresses from underground activities affecting the overburden dumps. This study uses a two-dimensional finite element (FE) analysis program to understand the stability analysis of overburden dumps above old underground workings. The factor of safety (FoS) is determined using the strength reduction technique which highlights the impact of underground excavations on overburden dump stability by highlighting the required strength reduction factor (SRF). In order to analyse the overburden dumps with the presence and absence of old underground workings, numerical models were created for various dump heights. The overburden dumps with underground workings exhibited SRF values ranging from 1.78 to 2.05, while the dumps without underground workings had SRF values ranging from 1.81 to 2.55. The displacement of the overburden dump material, which results in 7 mm of horizontal displacement and 29 mm of vertical displacement, indicates a significant impact of underground workings on the stability of the overburden dumps. This study highlights the importance of considering underground workings in the design and management of overburden dumps to ensure safety and stability. © 2025, World Researchers Associations. All rights reserved.Item Geotechnical Investigations of Coal Mine Waste Dump Material(World Researchers Associations, 2025) Harish, P.; Chandar, K.R.Mining is an essential activity for obtaining the raw materials required for infrastructure and energy needs. During the extraction of coal, a significant amount of overburden (OB) material is generated. Managing the overburden produced by mining activities demands a substantial land for disposal which can be quite challenging in limited spaces. Consequently, it becomes imperative to design safe coal mine OB dumps, optimizing the use of available ground space. The challenge of ensuring the stability of overburden dumps is directly linked to the geotechnical properties of these materials. Therefore, it is crucial to characterize the properties of the dump material accurately to assess its engineering properties reliably. The focus of this study is to outline the various testing procedures necessary for the proper characterization of dump materials to ensure the stability of the dumps. Additionally, the study provides an analysis of laboratory test data and presents typical results from a case study. © 2025, World Researchers Associations. All rights reserved.