IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
Not a member yet
2618 research outputs found
Sort by
Field and simulation studies for mechanised depillaring below incompetent geological formations of an Indian coalmine
No full textA fully mechanised mining method using continuous miner (CM) for pillar extraction in single-pass is introduced in the year 2010 at Pinoura Mine of South Eastern Coalfields Limited, Bilaspur in India. Overall mining cycle time is reduced by single-pass pillar extraction as it does not require drivage of split galleries in pillars and support installation for such galleries. Further, inherent technical abilities of the deployed CM for faster cutting and quad-bolter for supporting, helped in faster recovery of pillars without creating any strata control issues. Rate of face advance varied between 5-15m/day with an average of 8m/day. Field observations found that CM based single-pass extraction is capable in dealing with the strata control issues during depillaring under weak and laminated (incompetent in nature) roof layers having rock mass rating value around 42. A total of eleven panels, have been depillared under the weak and laminated geology, ranging depth of cover from 59 to 149m in different panels of the mine. During field investigations in these panels, a maximum of 2.89MPa induced vertical stress is recorded and influence of caved roof over underground mining structures is observed up to 15m in the out-bye from the goaf edge. This paper deals with estimation of snook size and limiting roof movement value based on numerical simulation and field studies during the single-pass extraction below the incompetent geological formations
Multivariate linear regression models for predicting metal content and sources in leafy vegetables and human health risk assessment in metal mining areas of Southern Jharkhand, India
No full textThe present study was intended to investigate the metal concentrations in the leafy vegetables, irrigation water, soil, and atmospheric dust deposition in the iron and copper mining areas of Southern Jharkhand, India. The study aimed to develop a multivariate linear regression (MVLR) model to predict the concentration of metals in leafy vegetables from the metals in associated environmental factors and assessment of the risk to the local population through the consumption of leafy vegetables and other allied pathways. The developed species-specific MVLR models were well fitted to predict the concentration of metals in the leafy vegetables. The coefficient of determination values (R2) was greater than 0.8 for all the species-specific models. Risk assessment was carried out considering multiple pathways of ingestion, inhalation, and dermal contact of vegetables, soil, water, and free-fall dust. Consumption of leafy vegetables was the major route of metal exposure to the local population in both the metal mining areas. The average hazard index (HI) value considering all the metals and pathways was calculated to be 5.13 and 12.1, respectively for iron and copper mining areas suggesting considerable risk to the local residents. Fe, As, and Cu were the major contributors to non-carcinogenic risk in the Iron mining areas while in the case of copper mining areas, the main contributors were Co, As, and Cu
Fischer-Tropsch synthesis over Pd promoted cobalt based mesoporous supported catalyst
No full textAbstract. The present study focuses on the catalytic conversion of syngas (CO + H2) through Fischer–
Tropsch (FT) route using two identically prepared 0.1 wt.% palladium promoted Mesoporous Alumina
(MA) and SBA–15 supported Co (15 wt.%) catalysts. The Fischer–Tropsch activity is performed in a fixed
bed tubular reactor at temperature 220 �C and pressure 30 bar with H2/CO ratio ~ 2 having Gas Hourly Space
Velocity (GHSV) of 500 h�1
. Detail characterizations of the catalysts are carried out using different analytical
techniques like N2 adsorption-desorption, Temperature-programmed reduction with hydrogen (H2-TPR),
Temperature-programmed desorption with NH3 (NH3-TPD), X-Ray Diffraction (XRD), and Transmission
Electron Microscopy (TEM). The results show that the SBA–15 supported catalyst exhibits higher C6–C12
selectivity (57.5%), and MA supported catalyst facilitates the formation of higher hydrocarbons (C13–C20) having a selectivity of 46.7%. This study attributes the use of both the support materials for the production
of liquid hydrocarbons through FT synthesis
Effect of Accuracy in Timings of Delay Detonators on Intensity of Blast Induced Ground Vibration
No full textEver-increasing demand of coal and metal have forced the mining industries to perform a big size blast in open pit and as well as in underground mines. In these circumstances, role of delay timings become very significant. In India, currently cord relays and MS connector with detonating fuse and Nonel delay detonators (shock tube) are very common. In recent time, electronic delay detonators have also been usen at large scale in open pit and underground metal mines. The delay-time accuracy in delay detonators play a very important role in controlling ground vibration as the calculation of maximum explosives weight per delays is mainly rely on this. In general, each detonator has an allowable error range of delay-time due to the difference in manufacturing process. In the initiation network, the errors of delay-time often accumulate gradually as the number of detonators increases. Therefore, theoretical delay-time and actual delay-time with error in the detonating network have been discussed in this paper based on the delay-time errors of detonators. The comparative test of blast-induced vibration has also been carried out using the NONEL and electronic/digital delay detonator. The test results showed that the very good quality of Nonel/digital electronic detonator must be used while blasting in sensitive locations in order to control the vibration. In this paper, the actual firing time of different delay detonators were analysed at open pit Coal and Iron mines and at underground lead zinc mine. The impact of scattering in detonator timing on vibration and fragmentation has been analysed
A proposed data acquisition system and algorithm for signal processing of moving-coil geophone’s output
No full textThe study of different types of vibrational and seismic movements is important for exploration in strata monitoring, machine health monitoring, earthquake detection, etc. In order to study these vibrational movements, it needs to be acquired first for analysis. Data acquisition using the seismic sensors is a challenging task. This paper presents a data acquisition system developed to acquire seismic signals from a moving-coil geophone. The paper also discusses a signal interpretation algorithm that is devised to perform automatic detection of a seismic event occurrence by separating through the waveform and non-waveform components in the sensor’s output using Gaussian naive Bayes classifier and Kernel density estimation technique. The proposed method is effective in the identification of a useful signal and identification of its nature of origin. Accuracy of the algorithm was 99% for the waveform classification. Sensitivity of the data acquisition system for the seismic sensors was 1.589 µm s–1. Further, the developed data acquisition system and the algorithm can be used in mines for seismological studies aimed at separating the vibration signal generated due to explosion and the one caused due to Earth’s tectonic and seismic activities
Study on the failure of guide ropes used in mines
No full textThe skips/cages in mine hoisting have to be guided to achieve high hoisting rates. Steel guide ropes are used in hoisting because they can safely guide the skips/cages and have been observed to be economical. Guide ropes are static in nature and are thus more prone to corrosion. An investigation into the causes of failure of a guide rope is discussed in this paper. The study consists of physical examination, examination of wear and corrosion, macro- and micro-examination, examination of the breaking load and individual tensile strength measurement of the rod. The main cause of failure is found to be corrosion. Heavy abrasion and corrosion together causes a substantial reduction in diameter of more than 60%. Corrosion raises the stress level and thereby weakens the grains, which is indicated by the cracks that have developed all along the grains as revealed through micro-examination. This affects the breaking strength and reveals a 37% loss of strength, as a result of which failure occurs
Source rock properties and pore structural features of distinct thermally mature Permian shales from South Rewa and Jharia basins, India
No full textSource-rock properties and pore structural properties of Permian shales (Barakar Formation) were evaluated from two Indian basins, with contrasting thermal maturities. South Rewa basin shales were marked by lower thermal maturities, while higher thermal maturities were shown for the shales from the Jharia basin. However, one sample from the South Rewa basin showed unreliably high Rock-Eval Tmax. Examination of the S2 curve showed very low flame ionization detector (FID) value, and thereby indicating the unreliability of the Tmax. However, the Rock-Eval oxidation temperature-peak (S4Tpeak) was observed to show reliable maturity estimate for the sample. The results presented establish the reliability of S4Tpeak as a maturity proxy for shales marked by unreliable pyrolysis signatures. Fractal analysis of low pressure N2 gas adsorption data and pore size distribution trends revealed presence of complex porous structures within the Jharia basin shales, while showing less complicated simpler structures within the South Rewa shales. While two fractal dimensions were observed to be present in the thermally mature Jharia shales, the differences in slopes of the two fractal segments showed minimal variation for the South Rewa shales, indicating the influence of thermal maturity levels on fractal properties
Organo-inorganic facets of shale gas reservoir of Jharia Basin of Damodar Valley, India
No full textThe Mahuda-Kapuria block of the Jharia Basin, Damodar Valley comprises thick shale sequences of Shibabudih (>180 m) in Barakar and Hariharpur shale (>40 m) in Barren Measures Formations. The ternary organic facies of maceral shown the trend of anoxification, resulting in higher maceration as a function of terrestrial-marshy depositional conditions. Subsequently, it supported the tissue preservation and carbon enrichment contributing to the formation of shale matrix. H/C vs O/C plot shown Type III/IV kerogen transformed from fluvio-humid to dry terrestrial depositional conditions followed by diagenesis, cata- and metagenesis processes. Also, the range values of Tmax (442–558 °C) and HI (25–345 mg HC/g TOC) confirms the significantly matured source rock having the input of dominantly type III/IV kerogen. The S1 and S2 specify (0.07–2.54 mg HC/g rock, 0.58–20.14 mg HC/g rock) the presence of substantial free/adsorbed hydrocarbon gases and uncracked hydrocarbon compounds. The large content of SiO2, Al2O3, and Fe2O3 account for 85–95 % of the samples point towards granitic source rock of sediments. The high CIA and low ICV values denote the compositional maturity of the shale due to conversion of feldspars to Al-bearing clays through intense geochemical weathering and alteration. The positive trend of organic weight with Langmuir volume (VL) and TOC specify the organic carbon present in shale mainly contributes to the formation of pore containing matrix system and adsorption of methane in shale pores. The mineralogy of shale directly controls the tensile strength, uniaxial compressive strength, Young's modulus, Poisson's ratio and brittleness of shale beds. Further, it is observed that the brittleness of shale beds exhibits higher axial strain with a small region of elastic behaviour by the influence of the hydrous property of kaolinite and illite. The proposed empirical EMBI for estimation of brittleness indicated moderate brittle characteristics of shale beds
Deciphering protein microenvironment by using a cysteine specific switch-ON fluorescent probe
No full textFluorescent probes provide an unparalleled opportunity to visualize and quantify dynamic events. Here, we employ a medium-size, cysteine specific coumarin based switch-ON fluorescent probe ‘L’ to track protein unfolding profiles and accessibility of cysteine residues in proteins. It was established that ‘L’ is highly selective and exhibits no artifact due to interaction with other bystander species. ‘L’ is able to gauge subtle changes in protein microenvironment and proved to be effective in delineating early unfolding events that are difficult to otherwise discern by classic techniques such as circular dichroism. By solving the X-ray structure of TadA and probing the temperature dependent fluorescence-ON response with native TadA and its cysteine mutants, it was revealed that unfolding occurs in a stage-wise manner and the regions that are functionally important form compact sub-domains and unfold at later stages. Our results assert that probe ‘L’ serves as an efficient tool to monitor subtle changes in protein structure and can be employed as a generic dye to study processes such as protein unfoldin
Effects of Elevated Temperatures on the Microstructural, Physico-Mechanical and Elastic Properties of Barakar Sandstone: A Study from One of the World’s Largest Underground Coalmine Fire Region, Jharia, India
No full textExperimental investigations of the effects of elevated temperature on microstructural, mineralogical, physico-mechanical and elastic properties of rocks were carried out to understand the effect of underground coal fire along with thermal damage and failure initiation in Barakar sandstone from the Jharia coalfield, India. Discolouration analysis, petrographic studies, scanning electron microscopy, thermogravimetry, differential thermal analysis and electron probe micro analysis were carried out to understand the microstructural and mineralogical changes in thermally treated samples. The experimental results suggest that the changes in investigated properties follow three characteristic thermal zones: zone I (25–300 °C), zone II (300–500 °C) and zone III (500–800 °C). Among all, zone II is a prominent transition region where a rapid increase in crack density, porosity and thermal damage is observed along with a sharp reduction in seismic wave velocities, uniaxial compressive strength, tensile strength and elastic parameters. Development of thermal stress-induced intergranular and intragranular micro-cracks, evaporation of organic matters, and dehydration and thermal decomposition of minerals are the most conspicuous reasons for the observed changes in this zone. Zone III is characterized by phase transformation of quartz, recrystallization and partial melting of cement and phyllosilicates that filled some of the existing micro-cracks, resulting in a local change of porosity, strength and elastic properties. Developments of different failure modes are observed in different temperature ranges such as simple shear along a single plane in zone I, progressive growth of Y-shaped (double plane) shearing in the zones II and III (400–700 °C) and axial splitting at 800 °C. The results from this study provide comprehensive elaboration of thermal effects on sandstones at a particular temperature range