Faculty Publications
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Item Induced stresses in blasting gallery panel during depillaring based on field instrumentation(CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2012) Kumar Reddy, S.; Sastry, V.R.Selection of a suitable mining method for economical and safe underground extraction of a thick coal seam is an extremely delicate process and brings a number of geo-technical parameters into consideration. In fact, single lift working of full thickness of a thick coal seam has always a verge over the multi slice working due to favorable economics and high production and productivity. Charbonnage de France (CdF) proposed Blasting Gallery (BG) for extraction of virgin thick seams as well as developed pillars in thick seams in single lift. The method was very successful resulting in 85% of extraction with high productivity. But, this method experienced strata control problems during final extraction. Due to strata problems, the method was not successful at East Katras Colliery where overriding of the pillars occurred in one panel. Two BG panels (BG 2/2 and BG 1/10 panels) at GDK No. 8 Incline, Singareni Collieries Company Ltd. (SCCL) were also closed prematurely due to strata problems. In this paper, strata monitoring data of stress cells in pillars of a blasting gallery panel is analyzed for the induced stresses in a Blasting Gallery panel during depillaring in specific geo-mining and working conditions of a underground mine in Southern part of India. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.Item Gallery monitoring in blasting gallery panel during depillaring - A case study(2013) Kumar Reddy, S.; Sastry, V.R.About 50% of coal reserves in India are in seams thicker than 4.5m, which come under the category of thick seams, the exploitation of which is consistently posing challenges to the mining engineers. Extraction of thick seams by conventional hand section method is neither productive nor effective from the conservation point of view. The percentage of extraction by hand section mining in thick seams is as low as 25-30%. Sand stowing for working of thick seams cannot be considered as an option because the cost is prohibitive. Sand has become an increasingly scarce commodity along with timber. Blasting gallery (BG) method of depillaring thick coal seam is one of the productive methods with high production, productivity, economic and conservation. In this method, stability of workings and easily cavability of goaf is very important for safely extraction of pillars, safety of men and machinery. In this paper, strata monitoring data of load cells in galleries of a blasting gallery panel, where spoiling in pillars, instability of galleries and displacement of supports are monitored and analyzed during depillaring in specific geo-mining and working conditions of a underground mine in southern part of India.Item Stress Distribution on Blasting Gallery Barrier Pillar due to Goaf Formation During Extraction(Springer India sanjiv.goswami@springer.co.in, 2016) Kumar Reddy, S.; Sastry, V.R.Semi-mechanised blasting gallery mining is a sustainable option to achieve higher production and productivity from underground thick coal seams. Judicious design of underground blasting gallery panel requires understanding of stress distribution on barrier pillars during different stages of extraction. This paper presents a study of stress distribution in and around barrier pillar for the different stages of extraction in the blasting gallery panel. Finite difference analysis taken up for final excavation (depillaring) in the panel with different stages of extraction. Analysis revealed that the stress transferred on barrier pillar increased as progress of excavation increased. Maximum stress was observed at a distance of 10 and 12 m from the pillar edge for virgin and goaved out panel sideby respectively, which gradually decreased towards centre of the pillar. © 2015, The Institution of Engineers (India).Item Subsidence Analysis for Old Abandoned Board and Pillar Coal Mines Using ANSYS and Monte Carlo Simulation(Pleiades Publishing, 2023) Akhil, A.; Pal, S.K.; Tripathi, A.K.; Kumar, G.Abstract: Mine Subsidence is a phenomenon of lateral or vertical ground movement caused by a failure initiated at the mine level of man-made underground mines and an abandoned mine is a site where mining activities occurred but acceptable mine closure and reclamation did not take place or was incomplete. Subsidence is one of the major problems which is faced over an old abandoned mine. Presently there are limited means or methods which can predict subsidence over an old abandoned coal mine at a shallow depth efficiently and the precautionary methods that should be taken in these situations. This research paper will cover the possible causes which can lead to subsidence above an old abandoned board and pillar coal mines at a shallow depth. The research includes the calculation of the factor of safety for pillars and analysis of FoS using ANSYS and Monte Carlo Simulations for ascertaining subsidence. An old abandoned coal mine of South Eastern Coalfields Ltd. (SECL, a subsidiary of Coal India Limited), was considered for the study of coal pillar fatigue and eventual crushing of pillars over a long duration of time, simulation analysis of stress and strength of coal pillars over a long period, change in behavior of factor of safety as the dimension of the pillars changes. © Pleiades Publishing, Ltd. 2024.