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 Classification of Stability of Highwall During Highwall Mining: A Statistical Adaptive Learning Approach(Kluwer Academic Publishers, 2015) Ram Chandar, K.; Hegde, C.; Yellishetty, M.; Gowtham Kumar, B.The depleting coal deposits day by day required the introduction of novel methods of mining like highwall mining. Highwall mining is a method of extraction of coal blocked in the highwall. The method involves considerable challenges in the area of roof control and most importantly the stability of the highwall itself. Highwall mining has gained considerable importance all over the world, owing to the fact that the coal otherwise would not be extracted forever. This paper aims to assess the influence of varying conditions which can affect the stability of the highwall during highwall mining. The effect of gallery length, width of pillar and number of galleries are systematically studied through field investigations where a highwall mining was adopted first time in India. Initially, assessment was carried out using a numerical modelling approach and then the stability of the highwall is classified using multilinear regression, logistic regression and naive Bayes classifier. This will provide a mechanism to predict the stability of the highwall in future cases of similar conditions. The classification is done using statistical adaptive learning methods and a comparison of the methods is done. © 2014, Springer International Publishing Switzerland.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 Sonar mapping of abandoned water-logged underground coal mine and backfilling operation using underwater camera(Inderscience Publishers, 2021) Pal, S.K.; Tripathi, A.K.; Panda, S.; Palaniappan, S.K.The paper describes mine mapping and backfilling work carried out during field experimentations on simple hydraulic gravity blind backfilling method for the stabilisation of ground above old abandoned waterlogged underground coal mine of Eastern Coalfields Limited (ECL), India. The section of the abandoned mine to be backfilled was explored using the underwater remote operated vehicle (ROV) camera before actual backfilling work. The use of sonar imaging facility of the ROV camera for mapping of the underground waterlogged area to be backfilled is described. The plotting of gradual progress of sand bed as the filling progressed in different stages through different boreholes as monitored from surrounding camera boreholes is also described. © © 2021 Inderscience Enterprises Ltd.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.