IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
Not a member yet
2618 research outputs found
Sort by
Multiphase assessment of post-mining effect on railway structures: A case study of Jharia Coalfield
No full textSubsidence-associated damage to surface structures like railway tracks over old mine workings instigate catastrophic impacts on human lives. The complexity of investigating old mine workings pose challenges owing to unapproachability restricting visual access, incomplete historical plans, limited record information, etc. The crux in studying unapproachable areas circumscribes the ambit of in-depth research. Thus, the framework of the investigational approach has been addressed in three segments (subsidence investigation, geophysical investigation and coal pillar stability analysis) to gather additional records to culminate the safety of the railway track located above old workings. A subsidence investigation has been conducted for a period of 9 months to assess the present status of ground movement along the railway track. Integration of geophysical investigation led to evaluating the impact of old workings on the overlying strata that can lead to subsidence in the future. Electrical resistivity tomography (ERT) technique has been used to assess the status of old underground workings, which resulted in the identification of sub-surface void as well as overlying strata disturbance status. Numerical modeling using FLAC3D, including the empirical method, has been undertaken to investigate the stability of coal pillars with respect to pillar dimensions and rock properties. The multiphase investigation resulted in arriving at a concrete understanding of the ground condition with respect to stability
Non-Coking coal as an additive to enhance properties of groundnut shell reinforced polypropylene composites
No full textGroundnut shells (GNS) are renewable and sustainable sources that can reinforce polypropylene for composites intended for interior building and other applications. However, the hydrophilicity, low thermal and noise insulation of GNS reinforced polypropylene (PP) necessitate the use of additives to improve properties. In this work, non-coking bituminous coal was used as an additive to improve the properties of GNS-PP
composites. Up to 30% of coal particles were included and the changes in tensile, flexural properties and noise and thermal insulation were studied. Morphological analysis showed
limited interaction of coal with GNS or PP and consequently, there was only marginal improvement in the mechanical properties. However, moisture sorption of the composites decreased by 25% and the limited oxygen index increased to 27 from 24 without any coal. The presence of coal increases sound absorption and the noise absorptio
Understanding urban groundwater pollution in the Upper Gangetic Alluvial Plains of Northern India with multiple industries and their impact on drinking water quality and associated health risks
No full textUdham Singh Nagar district is having various industries like paint, textile, sugar, petrochemical, paper and automobile which produces different kind of contaminants including heavy metals in the environment and pollute groundwater. Therefore, in the present study, fifty groundwater samples were collected from this region and analyzed for 7 physicochemical parameters (pH, electrical conductivity, total dissolved solids, bicarbonate, chloride, sulphate, nitrate), 4 metals (calcium, magnesium, sodium, potassium) along with 6 heavy metals (Fe, Mn, Zn, Pb, Cd, Cr). Heavy metal pollution level in the groundwater was assessed by calculating and analysing heavy metal pollution indices (heavy metal pollution indices -HPI, m-HPI; heavy metal evaluation index- HEI) and risk assessment parameters (hazard quotient - HQ and hazard index - HI). Multivariate statistical analysis was also done to identify the sources of heavy metals and categorize groundwater quality. Concentration of Fe, Mn and Cr in 14%, 16% and 18% water samples exceeded the desirable limit. Piper diagram suggested that majority of groundwater samples were Ca–Mg–HCO3 type. HPI calculation indicated that no groundwater sample fall under high category of pollution. HEI and m-HPI indicated that 90% and 82% groundwater samples were found suitable for potable purpose respectively while on the basis of m-HPI, 3 groundwater samples were found under the unacceptable category. Non-carcinogenic hazards were observed which might be due to high chromium content. According to principal component analysis (PCA) and cluster analysis (CA), geogenic, anthropogenic and industrial activities were responsible for groundwater pollution. The values of HQ for Cr for both adult (13 samples) and younger people (9 sampling sits) surpass the unity. HI values indicated that groundwater samples from 14 sites were not suitable for drinking purpose. This is the first attempt of analyzing heavy metal pollution and health risk in Udham Singh Nagar district of Uttarakhand
Development of design norms for rib/snook during mechanised depillaring by continuous miner
No full textThis paper presents the efforts made to design irregular-shaped-heightened-rib/snook based on factor of safety (FOS) during mechanised extraction of already developed coal pillars by continuous miner. In situ monitoring of performance of different sizes of rib/snook with variation in their area, effective-width, width-to-height ratio and height under varying geo-mining conditions are studied comprehensively at 39 panels of 7 different mines and found a number of influencing factors affecting its design as per the field studies. Based on this study, a number of conceptual models are developed to understand the need of rib/snook and its interaction with different nature of roof at varying depth of cover. Further, a parametric study is carried out on calibrated numerical models by varying the area and height of rib/snook with nature of roof, depth of cover and panel width for the estimation of strength and stress over it. Empirical formulations are developed for estimation of a competent area, effective width and width-to-height ratio in a given geo-mining condition corresponding to a limiting value of FOS of 0.30–0.35. Further, the results of developed empirical formulations are validated with the field studies
Hydro chemical investigation of groundwater quality for drinking and irrigational purposes from industrial belt of Jharkhand, India
No full textGroundwater (GW) is a key water resource for domestic and agricultural activities. Industrial activities often affect GW chemistry. Therefore, assessment of GW quality for drinking and irrigation purposes is required to be assessed to ensure its suitability in and around industrial setups. Present study was planned to investigate the GW suitability for domestic and irrigation purposes around Bokaro Industrial Area, Jharkhand, India. Sodium Absorption Ratio (SAR), Residual Sodium Carbonate (RSC), Permeability Index (PI), and percentage sodium (% Na) were evaluated for irrigation purposes, while pH, total hardness (TH), and electrical conductivity (EC), Total dissolve solid (TDS), F−, SO42−, HCO3−, Cl−, NO3−, Na+, K+, Ca2+, and Mg2+ for domestic usage. Results showed wide variation in the physicochemical characteristics as major cations were found in the order: Ca2+ > Mg2+ > Na+ > K+, while major anions were in the order of HCO3−> Cl−> SO42−> NO3−> F−. The range of pH 6.15–7.73 and EC was 230–1676 μS cm−1, while TH, Cl−, HCO3−, SO4−, NO3-, F−, Ca2+, Mg2+, Na+, and K+ was varied from 66–743, 3.3–289.9, 61–392, 5.5–148.5, 1.2–61.4, 0.66–4.38, 14.5–170.3, 4.9–80.2, 12.3–102.7, and 0.37–5.7 mg/L, respectively. It was found that GW quality at most of the sites was suitable for irrigation and domestic purpose except at few locations. Further, results revealed that industrial activity has noticeable impact on the groundwater quality but, the overall suitability indicates a potential recharge system for the aquifers in the area which maintains the GW chemistry. Albeit alarming values of some of the GW parameters, namely, pH, total hardness, F−, HCO3−, Cl−, NO3−, Na+, Ca2+, and Mg2+ at some locations require attention to design and execute effective water management plans to avoid possible irrigation and human health risks in future
Investigations on the Influence of Applied Thrust on Rock Penetration Rate by a Raise Boring Machine Using Numerical Simulation and Experimental Trials
No full textRaises are vertical or inclined openings made to connect two levels of an underground metalliferous mine. They are developed using drilling and blasting-based technique or by mechanical means. Raise boring machines (RBM) have evolved in recent years, which provide quicker and safer raise excavation. The penetration rate using RBM has influenced applied thrust. The required thrust to enhance penetration rate with optimal use of energy would be different under varying geological and geotechnical conditions. In this study, the influence of applied thrust on penetration rate using RBM has been investigated. The investigation has been made for two different rock types, amphibolite (AMP) and garnet-biotite-sillimanite-gneiss (GBSG). The numerical simulation model was developed for this purpose using Ansys-Explicit Dynamics. The induced tensile stress under different conditions of applied thrust has been analysed in the calibrated numerical model. The model output shows the power trend between the parameters. The experimental data on penetration rate was also collected along with the respective operational parameters. A statistical analysis has been carried out for the gathered data. The analysis of data also shows a power trend between thrust per cutter and penetration rate in both rock types and hence validates the numerical simulation-based output. Based on the outputs of the numerical simulation and empirical study of the experimental data, the optimum thrust per cutter for excavation in both rock types is in the range of 12–14 tons. The approach used in this study can be helpful for predicting the optimal operational parameters of raise boring machines under different geological/geotechnical condition
Comparative Studies of Co/SBA-15 Catalysts Synthesized with Different Silica Sources Including Coal Fly Ash for Fischer-Tropsch Synthesis
No full textSBA-15 is synthesized using triblock copolymer Pluronic P123 as the structure directing agent and different silica sources such as tetraethyl orthosilicate (TEOS), sodium metasilicate, coal fly ash (CFA) derived supernatant and a mix of sodium metasilicate, CFA-derived supernatant for comparative study towards Fischer-Tropsch synthesis (FTS). The active metal cobalt (15 wt. %) has been impregnated in each support via the wet impregnation technique. The catalysts and supports are characterized by N2 adsorption-desorption, Field Emission Scanning Electron Microscopy (FESEM), High-Resolution Transmission Electron Microscopy (HRTEM), X-ray Diffraction (XRD), X-ray Energy Dispersion Spectrophotometer (EDX), Fourier Transform Infrared (FTIR), and Temperature Programmed Reduction (TPR). The catalytic performance of synthesized catalysts for the FTS has been investigated in a fixed bed tubular reactor at T=220 °C, P=30 bar, and GHSV=500 h−1 using simulated syngas composition equivalent to coal-derived syngas using air blown fixed bed gasifier having H2/CO molar ratio of 2 : 1. The maximum CO conversion and middle distillate (C6−C20) selectivity is observed as 59.2 % and 84.6 % respectively for the catalyst support synthesized from mix of sodium metasilicate and CFA-derived supernatant
Modelling of Fragile Coal Mine Roof and Estimation of Rock Loads—Some Empirical and Numerical Methods
No full textWeak, layered, and fragile rock mass formation, if not supported properly, is subject to roof failure thereby affecting safety and productivity in underground coal mines. Though Central Mining Research Institute – Indian School of Mines Rock Mass Rating (CMRI-ISM RMR) based well-defined support design guidelines are established, still occurrence of roof failures in underground coal mines is a real matter of concern for mining engineers and researchers. Numerical modeling techniques are successfully used by several researchers by simulating rock mass condition for stability assessment of mine openings. The analysis becomes crucial in case of weak and fragile rock formation. The present research envelops the determination of 31 cases of rock load by CMRI-ISM RMR under different geo-mining conditions followed by the development of modified Rock Mass Rating (RMR), i.e., rock mass rating dynamic (RMRdyn) by incorporating P-wave velocity as a new parameter. The rock load determined using RMRdyn and numerical models was correlated and found in close agreement. In addition, the deviation in rock load determined by all the three approaches, i.e., CMRI-ISM RMR, numerical modeling, and RMRdyn, was compared with the actual field data. The percentage deviation obtained in RMRdyn and numerical modeling is less compared to CMRI-ISM RM
Estimating the requirements of pressure drop during fluidization-bubbling regimes in fluidized bed with different conical distributors
No full textThe pressure drop across the distributor signifies the total pressure drop and ensures desired fluidization in the fluidized bed. This study estimates the pressure drop requirements for 1.2 and 2.05 mm particles utilizing two distinct perforated type conical distributors with 154 and 302 orifices, respectively. The investigation was carried out in a cold flow condition. The pressure drop across the distributor was introduced in this investigation by filling bed material in the conical portion of the distributor. To estimate the bed pressure, a combined pressure drop of the conical distributor with and without bed material was approached. Explicitly, pressure drop requirements for the minimum fluidization and bubbling regimes have been focused on and presented in this work. In view of bed pressure, an attempt has been made to establish a relationship for pressure requirements across distributors. The integration and estimation of pressure drop across distributor with bed material in conical portion could be very beneficial in view of the fluidized bed. As the bed height increased, the pressure increased, but the pressure drop ratio decreased for the selected particles. The distributor features a higher number of orifices that demonstrate lower pressure requirements during fluidization and bubbling regimes. This study emphasizes the desired pressure requirements for the fluidized bed