IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Impact of the Combined Application of Biochar and Compost on Mine Soil Quality and Growth of Lady's Finger (Abelmoschus esculentus)
No full textAmelioration of mine soil is challenging because of the lack of biologically active organic matter. The study was aimed to recycle yard waste into compost and biochar and to use them to reclaim mine soil. Biochar prepared at 350 °C showed the highest stable organic matter yield index and was used for the experiments. Lady’s finger was grown on mine soil amended with biochar (1%–5%), compost (2%–10%), and biochar-compost mixtures (2%–10%). Mine soil pH increased in all treatments. Mine soil dehydrogenase activity (42%–224%), microbial biomass carbon (4%–257%), and hydrolase activity (3%–230%) increased by combined application of biochar and compost. Lady’s finger plant height, biomass, and fruit yield were superior in biochar–compost mixtures compared to biochar and compost alone treatment. Thus the use of compost along with biochar could be recommended for reclamation of mine soil
A comparative kinetic study between TGA & DSC techniques using model-free and model-based analyses to assess spontaneous combustion propensity of Indian coals
No full textKinetic study of coal was carried out using simultaneous thermal analysis (STA) technique to assess the spontaneous combustion propensity of coal samples collected from various Indian coalfields having both fiery and non-fiery seams. The kinetic parameters were estimated by using both model-free and model-based analysis for both TGA & DSC data. The model-based method comprises four different consecutive reaction steps, viz. A→B→C→D→E for the spontaneous combustion process and the second reaction step (B→C) were used for this investigation. Chemometric analysis was applied to know the relation between the proximate analysis and activation energy of the samples using model-free and model-based techniques. The activation energy for the second reaction step of the model-based method for both TGA and DSC data showed a good relationship with the standard methods i.e., crossing point temperature (XPT) and Tgign of the samples. It indicates that the activation energy values at the oxidation stage (2nd stage) play a significant role in the spontaneous combustion propensity of coal. The study also reveals that the model-based analysis provided better results in comparison to model-free analysis to assess the spontaneous combustion propensity of coal
High entropy alloy nanoparticle - graphene (HEA:G) composite for non-enzymatic glucose oxidation : optimization for enhanced catalytic performance
No full textHigh entropy alloy (HEA) metal nanoparticles engineered graphene composites (HEA:G) were produced via green approach involving mechanical milling and sonication assisted exfoliation. Mixture of metal powders and graphite (metal-to-graphite weight ratio: 20%, 50%, 70%, 90%) were ball milled and exfoliated. As produced 20:80, 50:50, 70:30, 90:10 - HEA:G composites electrochemical activity was explored using the redox probe potassium ferricyanide [K3Fe(CN)6] and for the non-enzymatic detection of glucose. From cyclic voltammetry(CV) response, the significant electron transfer kinetics for K3Fe(CN)6 was found for 20:80, 50:50, 70:30 composites, whereas reduced activity was observed with 90:10. Also, 20:80, 50:50, 70:30 composites exhibited notable oxidation of glucose in 0.1 M PBS compared to 90:10. The anodic current indicating oxidation of glucose was found to be increasing linearly with HEA:G composite - 20:80<50:50<70:30. However, DPV measurements indicate better working potential from 0.45 V to 0.4 V followed by saturation in the oxidation currents for 50:50 and 70:30 composites. The sensitivity obtained for HEA:G composites 20:80, 50:50, 70:30 were 12.09
, 22.99
, 18.2
respectively. Hence, 50:50 and 70:30 are the efficient composites exhibiting excellent catalytic activity indicating the prominence of HEA:Graphene composites and their synergism
Regio- and Chemoselective Access to Dihydrothiophenes and Thiophenes via Halogenation/Intramolecular C(sp2)–H Thienation of α-Allyl Dithioesters at Room Temperature
No full textAn operationally simple, practical, and efficient cascade approach employing α-allyl dithioesters and NBS/NIS has been achieved to access a series of dihydrothiophenes and thiophenes containing diverse functional groups of different electronic and steric natures in good to excellent yields at room temperature in open air. The reaction proceeds via the electrophilic addition of a halogen source (NBS/NIS) to an allylic double bond, followed by intramolecular regio- and chemoselective S-cyclization. This protocol avoids potential toxicity and tedious work-up conditions, and features easy synthesis from readily available starting materials under catalyst-free conditions. Furthermore, 4,5-dihydrothiophenes were aromatized to thiophenes by treatment with KOH in DMF at room temperature. A probable mechanism for the formation of dihydrothiophenes and thiophenes from α-allyl dithioesters has been suggested. Notably, a large-scale experiment and the transformations of products indicated the potential utility of this reaction compared to competing processes for the synthesis of 4,5-dihydrothiophenes and thiophenes
Petrographic and Geochemical Controls on Methane Genesis, Pore Fractal Attributes, and Sorption of Lower Gondwana Coal of Jharia Basin, India
No full textThe Barakar coal seams of Jharia Basin have been evaluated for the geochemical and petrographic control of coalbed methane (CBM) reservoir characteristics. The coal core samples are analyzed for the total gas content, gas chromatography, stable isotopes (δ13C1), and geochemical, petrographic and vitrinite reflectance. The significant face (1.6–7.6%) and butt (0.9–5.3%) cleat intensities specify the brittle characteristics of coal seams and also favor the gas flow mechanism. The thermal cracking position of hydrocarbon compounds was evaluated, which signifies the excellent source rock potential of coal for gas genesis. The inputs of type III and IV organic matter illustrated by the van Krevelan diagram signify thermally matured coal seams. The low values of sorption time (τ) between 2.1 and 5.6 days designate excellent diffusion characteristics that is favored by the cleat intensities. The values of total gas content and sorption capacity (VL) reveal that moderate saturation indicates a higher gas content, attributed to the seam thickness and thermal maturity. Similarly, the CH4 concentrations (89.4–96.6 vol %) display that the genesis pattern is a function of thermal maturity; however, some samples fall under the mixed type substantiated by the stable isotope (δ13C1) (−25.40 to −64.90‰), emphasizing bacterial hold by seasonal influx of freshwater. The ternary facies diagram (Vmmf, Immf, Lmmf) also supports notable generation of methane gas and storage in the coal seams of the Jharia Basin. The volume percentage of each maceral determined from petrographic study was used to estimate the fraction of conversion (f) of the organic content (0.19–0.97). The values of “f” indicate that the Barakar coal has undergone maximum conversion, which may be attributed to the older early Permian coal and placed at a greater depth after deposition due to the basin sink. The high fraction of conversion and thermal maturity may also be explained due to the existence of volcanic intrusion (sills and dykes). The uniformity in the distribution of functional groups is shown by Fourier transform infrared spectra representing moderate to stronger peaks of aromatic carbon (CO and C═C) between 1750 and 1450 cm–1, which indicates that the presence of a larger total organic carbon content likely validates the removal of aliphatic compounds during gas genesis. The variations in the BET curve have been categorized as H1 hysteresis following the type II adsorption pattern, suggesting that cylindrical pores and some of the coal samples have a type IV H4 hysteresis pattern, characterized as the slit type of pores. The average values of the pore diameter indicate the dominance of mesopores suitable for gas storage and release and hence a major part of the pore volume is contributed by the mesopores having a width mainly between 2.98 and 4.48 nm. The significant role of the meso-macropore network (D1 fractals) in methane storage of the coal matrix is represented by a moderate positive relationship of VL with D1, which accentuated that meso-macropores developed due to devolatilization and dehydration of organic matter and also by geochemical alteration of macerals and minerals formed heterogenetic inner surfaces suitable for gas adsorption. The estimated recoverable resource applying Mavor Pratt methods is 8.78 BCM, which is found to be a more realistic resource value for the studied CBM block
Assessing Ground Vibration Caused by Rock Blasting in Surface Mines Using Machine-Learning Approaches: A Comparison of CART, SVR and MARS
No full textGround vibration induced by rock blasting is an unavoidable effect that may generate severe damages to structures and living communities. Peak particle velocity (PPV) is the key predictor for ground vibration. This study aims to develop a model to predict PPV in opencast mines. Two machine-learning techniques, including multivariate adaptive regression splines (MARS) and classification and regression tree (CART), which are easy to implement by field engineers, were investigated. The models were developed using a record of 1001 real blast-induced ground vibrations, with ten (10) corresponding blasting parameters from 34 opencast mines/quarries from India and Benin. The suitability of one technique over the other was tested by comparing the outcomes with the support vector regression (SVR) algorithm, multiple linear regression, and different empirical predictors using a Taylor diagram. The results showed that the MARS model outperformed other models in this study with lower error (RMSE = 0.227) and R2 of 0.951, followed by SVR (R2 = 0.87), CART (R2 = 0.74) and empirical predictors. Based on the large-scale cases and input variables involved, the developed models should lead to better representative models of high generalization ability. The proposed MARS model can easily be implemented by field engineers for the prediction of blasting vibration with reasonable accuracy
Detection of subsurface cavity due to old mine workings using electrical resistivity tomography: A case study
No full textThe present study deals with the detection of underground concealed voids/cavities/galleries in Chinchuria railway station, Raniganjh coalfield in India for ground stabilization using electrical resistivity tomography (ERT) technique. Initially, numerical analysis of ERT data was carried out using Wenner–Schlumberger and dipole–dipole array configurations corrupted by 5–10% Gaussian random noise for better understanding of real field conditions. The two types of voids, i.e., water and air, filled in old mine workings were simulated accordingly in the forward model. The dipole–dipole array provides superior results compared to Wenner–Schlumberger array. Considerable accuracy of voids/cavities/galleries dimension could be acquired from dipole–dipole array. In field, two number of ERT profiles (Profile-AA′ and Profile-BB′) were conducted over the study area using said configurations. The data was acquired using Syscal-Pro resistivity imaging system with 96 electrodes and the data processing was carried out using the tomographic inversion software RES2DINV to analyse true resistivity based on the robust or blocky regularization inversion technique (L1-norm). High resistivity contrast with backgrounds in the occurrence of possible old mine workings consisting of hard rock and alternative coal pillars interconnected cavities and mining galleries was identified. Considering the indirect approach of ERT method, a borehole was being drilled along the profile-AA′ of dipole–dipole array, drilling and resistivity results indicated the presence of air-filled cavity associated with old mine workings. Hence, it is concluded that the technique used in this study is useful in increasing the technical merit of electrical resistivity interpretation for old mine workings areas
Performance Analysis of IoT-based underground miner’s tracking and wireless voice communication system
No full textThis paper addresses an integrated wireless-fidelity (Wi-Fi)
and radio frequency identification (RFID) based wireless
system which has been developed for tracking of miners,
wireless communication between miners and officials on
surface. The system provides a walk through model in mine
display and can predict mine-hazards. The system has been
developed for providing emergency response using Internet
of Things (IoT) enabled devices for tracking of trapped
miners in a particular underground mine located using
monitoring system and thereby sends real-time location to
the concerned management and rescue team. The network
performance has been analysed to assess the maximum
operating distance, packet delivery ratio (PDR) and data
communication capabilities. PDR was 6-7% more in normal
surface conditions than mine environment for same
transmission distance. This network analysis shows that
with increase in distance between miner and the end device,
the PDR decreases. Also increases in the number of hops in
between end device and mine coordinator reduces the PD