Faculty Publications
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Item Studies on gravity backfilling method for blind backfilling of abandoned coal mines(TMMOB Maden Muhendisleri Odasi, 2015) Pal, S.K.; Panda, S.; Tripathi, A.K.In this paper a new, simple and low cost gravity backfilling method for stabilization of ground above abandoned underground mines is proposed. Laboratory investigations carried out on this simple gravity hydraulic blind backfilling method to fill up a fully transparent model of a section of a bord and pillar mine, have indicated that deposition of the filling material surrounding the inlet hole occurs in a regular shape with full packing up to the roof. Some empirical relationships on maximum volume of sand throughput and spread of sand around the inlet hole have been developed with a view to help the practicing engineers. In the field trial the spread of sand in different directions has been witnessed using an ROV camera fitted with a sonar imaging system. The shape and nature of deposited sand bed surrounding the feeder hole in field and laboratory studies are alike. The empirical relationships developed under field conditions have also been found to be similar to those of laboratory model.Item Air quality assessment of Dhanbad District, India - A case study(2010) Anantharamu, A.; Singh, G.; Venkat Reddy, D.Ambient air pollution status in Dhanbad district is studied and presented in this article. The selection of Dhanbad is made considering its importance and the nature of activities taking place around the district. For the assessment of ambient air quality in Dhanbad, the following five locations were chosen: Main Gate of Indian School of Mines(ISM), Dhanbad: It is a site representing purely commercial activities and road traffic. Bankmore: It is one of the busiest marketing centres of the district and is surrounded by residential areas. All the vehicles going to Bokaro pass by this place and thus the traffic density is pretty high. Kusunda: It is a place 10.9 kilometres from Dhanbad Railway Station. It is just beside one of the coal mines, hence, all vehicles going to the mine passes through this place. Steel Gate: It consists of a small market. Trucks and other heavy vehicle are more frequent during night as this road connects to a highway. ISM Admin Block: It can be considered as a sensitive area since it is a very calm place where the usage of vehicles is minimum throughout the day. Monitoring of ambient air quality is done following the standard procedure prescribed in IS: 5182. In addition, the concentration of lead, zinc, cadmium, copper, manganese and iron metals in SPM is also monitored. The ambient air quality assessment was done in the month of June, 2009. The concentration of SPM was higher than the permissible limit in three locations namely ISM Main Gate, Bankmore and Steel Gate, while it was less than the permissible limit in other two locations, ISM Admin Block and Kusunda. Since the generation of SPM was mainly due to vehicular traffic it was expected to cross the limit in the above mentioned three locations as density of vehicular movement is very high. © 2010 CAFET-INNOVA TECHNICAL SOCIETY.Item Effect of width of gallery of highwall mining on stability of highwall: A numerical modelling approach(Inderscience Enterprises Ltd., 2014) Ram Chandar, K.R.; Kumar, B.G.Owing to continuous increased demand for coal, along with existing mining methods, some novel methods are being looked for. Highwall mining is such a method where considerable quantity of coal blocked in the highwall can be extracted to a great extent. The major challenge in highwall mining is roof control along with the stability of highwall. This method was introduced in one of the opencast coal mines first time in India. A systematic study was taken up using numerical modelling approach to assess the influence of width of gallery of highwall on stability of highwall based on field investigations. The width of gallery was taken as 3.5, 4.25 and 5.0 m. It was found that the stress and strain was more in case of 5.0 m wide gallery compared with 3.5 m wide gallery and the stress and strain values were more at the end point of galleries compared with the starting points of the galleries. The factor of safety values were decreased as the width of gallery increased from 3.5 m to 5.0 m. © 2014 Inderscience Enterprises Ltd.Item Experimental study for the assessment of suitability for vegetation growth on coal mine overburden(Inderscience Enterprises Ltd., 2015) Ram Chandar, K.R.; Chaitanya, V.; Raghunandan, M.E.Owing to increased production and productivity of opencast coal mines, large amount of waste rock is removed and stacked in the form of waste dumps. Positive utilisation of such waste rock not only saves considerable dumping land but also reduces problem of maintaining stable and environmentally friendly dumps. One of the major utilisation of waste rock is to use it for vegetation. Therefore a systematic investigation to study the fertile characteristics of overburden waste rock for vegetation was conducted. Waste rock samples collected from an opencast coal mine dump in South India were used in the laboratory experiments. Observations showed the suitability of mine wastes for vegetation when supplemented with additives/nutrients - bottom ash, fly ash, lime stone powder and secondary sludge from sewage treatment plants (STPs) were considered for this purpose as additives. Results suggest that the mine-overburden supplemented with sewage waste (atleast 25% by volume) to be suitable for effective vegetation. © © 2015 Inderscience Enterprises Ltd.Item Model studies on the efficiency of gravity blind backfilling method and evaluation of a pre-jamming indication parameter(CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2016) Pal, S.K.; Mukhopadhyay, S.K.; Panda, S.; Tripathi, A.K.This paper discusses experimental research on a fully transparent scaled model of a section of a Bord and Pillar mine working carried out to study in detail the effectiveness of hydraulic blind backfilling as a solution to reduce subsidence problem above old underground water-logged coal mines. The relative influence of sand and water flow rates on the areas of filling from a single inlet point has been studied in detail. Automatic data acquisition system was installed in the model to continuously record the sand and water flow rates along with the inlet pressure of slurry at the entrance of the model. Pressure signature graphs have been plotted directly with the help of computer. Pressure signature analyses for various slurry flow rates and sand concentrations have been carried out. Investigation has also been carried out on evaluation of a pre-jamming indication parameter, which could be used for indication of the final stage of filling. © 2016 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item A Critical Comparison of Regression Models and Artificial Neural Networks to Predict Ground Vibrations(Springer International Publishing, 2017) Ram Chandar, K.; Sastry, V.R.; Hegde, C.Blasting is important and an essential prerequisite in any opencast mine for fragmenting hard deposits. Blasting always produces unwanted effects like ground vibrations, noise and fly rock; among which ground vibrations effect is more on surrounding structures. Propagation of ground vibrations can lead to destruction of surrounding structures. Prediction of ground vibrations especially in terms of peak particle velocity is beneficial as opposed to conventional data monitoring techniques which can be expensive as well as time consuming. This paper uses predictors to estimate the intensity of ground vibrations and compares different methods of prediction methods like linear regression, multiple linear regression, non linear regression (NLR) and artificial neural networks. Intensity of ground vibrations generated from blasting operations was monitored in three different mines of limestone, dolomite and coal; obtaining about 168 ground vibration recordings in total. The statistical modelling or data-driven modeling has shown promise in the prediction of blast vibrations. Proposed a system of introducing site specific rock parameters like poison’s ratio, uniaxial compressive strength of rock and Young’s modulus to improve the correlation coefficient using statistical modelling (commonly called feature engineering in machine learning circles). © 2016, Springer International Publishing Switzerland.Item Musculoskeletal Disorders Among Dozer Operators Exposed to Whole-Body Vibration in Indian Surface Coal Mines(Springer, 2020) Jeripotula, S.K.; Mangalpady, A.; Raj, G.R.Dozer operators are frequently exposed to whole-body vibration (WBV) during the execution of their work. Occupational exposure to WBV in Indian surface coal mines was evaluated by measuring vibration intensity and duration of exposure. A triaxial accelerometer was placed on the operator seat surface for taking the readings. Based on frequency-weighted root mean square acceleration equivalent to 8-hr shift duration, i.e., (A(8)) all dozer operators have exceeded an Exposure Action Value (EAV) of 0.5 m/s2, and 90% of dozers did not exceed Exposure Limit Value (ELV) of 1.15 m/s2. Based on Vibration Dose Value (VDV (8)), all dozer operators have exceeded Exposure Limit Value (EAV) of 9.1 m/s1.75, but no dozer operators have exceeded Exposure Limit Value (ELV) of 21 m/s1.75. Further, an epidemiological study was performed for identifying the extent of musculoskeletal disorders (MSDs) among dozer operators. For the detailed study, 42 dozer operators and 22 controls were selected from 2 surface coal mines. The control group was not exposed to WBV. It was seen from the cross-sectional study that pain in the lower back was predominantly higher (83.33%) in the exposed group when compared with the control group (31.81%). Likewise, pain in the neck (47.61%), shoulder (42.85%), knees (42.85%), and ankle (11.90%) was higher in the exposed group than that of the control group (22.71%, 0%, 45.45%, and 4.54%). A significant observation among the exposed group was that there was degradation in the quality of life. The outcome of the study would assist in monitoring and mitigation of machinery-induced vibration diseases (MIVD) in India and generally applicable to most of the mechanized mines as well. However, comprehensive studies are still needed to enunciate the magnitude extent. © 2020, Society for Mining, Metallurgy & Exploration Inc.Item Assessment of Exposure to Whole-Body Vibration of Dozer Operators Based on Postural Variability(Springer, 2020) Jeripotula, S.K.; Mangalpady, A.; Raj, G.R.The main aim of this work is to evaluate whole-body vibration (WBV) of dozer operators based on three sitting postures (i.e., with 15° lean forward inclination posture, vertically erect posture with no inclination, and with 15° lean backward inclination posture) in Indian surface coal mines. A seat pad tri-axial accelerometer was used to collect WBV data from six dozer operators for three different sitting postures. Results showed that except for Dozer-1, 2, 4, and 5 operators during lean forward sitting posture and Dozer-4 operator during vertical erected posture, no other dozer operators have exceeded an exposure limit value (ELV) of 1.15 m/s2 in any of the considered sitting postures. Similarly, the vibration dose value (VDV) based on exposure action value (EAV) of 9.1 m/s1.75 has surpassed for all the dozers. But no dozer operator has exceeded an exposure limit value of 21 m/s1.75. The outcome of the study infers that based on “above health guidance caution zone (HGCZ)” for daily vibration exposure, i.e., A(8) measurements, for the operator sitting in lean backward postures the vibration amplification was reduced by 32.89% less compared with lean forward posture and 16.23% less when compared with vertically erected posture. Similarly, based on VDV(8), the exposure to vibration for the lean backward posture was reduced by 33.34% when compared with lean forward posture and 17.11% less when compared with vertically erected posture. Based on the above observation, it is concluded that lean back inclination with a trunk flexion of 15° is a favorable sitting posture, as it exposes the dozer operators to minimum vibration. © 2020, Society for Mining, Metallurgy & Exploration Inc.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 Analysis of Fault’s Effect on the Highwall Stability of Medapalli Open Pit Coal Mine(Springer Science and Business Media Deutschland GmbH, 2023) Kumar Reddy, S.K.Mining operations can have a significant impact on the stability of the surrounding area. One example is the Medapalli open pit coal mine in southern India. The mine is a large excavation working at a depth of 165 m that can reach up to 200 m. The western side highwall has locked-up coal reserves in the mine, but concerns about the geologically disturbed regions have resulted in complications and significant challenges. Surface tension cracks around the excavation became visible in 2018, prompting intensive monitoring, protective measures, and numerous geotechnical analyses. The area, however, has a rich tectonic history, with faults interacting with soil movements. Proper geotechnical investigations were used in this work to analyse the stability of the highwall due to faults' effects on the area's reaction due to mining operations. The findings in the study highlighted the significance of flaws in the ground movement due to improper design of the highwall fault interaction area. The presence of the fault increases the likelihood of tensile cracks and subsidence at the highwall's surface level, significantly worsening the mining activities in the area. The analysis reveals that complex geological features, such as the presence of faults roughly parallel to the highwall slope profile, can exacerbate the mining operations in the surrounding environment. The recommended slope design with protective measures towards the west side disturbed highwall area helps safely excavate the western side highwall locked-up coal reserves in the Medapalli open pit mine. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.