IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Comprehensive review on principles and practices of underwater drilling and blasting, its environmental impacts, and mitigation techniques
No full textUnderwater drilling and blasting techniques have been developed to overcome the challenges posed
by various subaquatic operations, including marine construction, oil and gas exploration, and underwater
mining, demolition, dredging and excavation, seismic surveys and marine research. The drilling operation is
followed by underwater blasting, which involves the creation of boreholes in submerged surfaces, such as sea
beds or riverbeds. Specialized drilling equipment is utilized, which can operate in aquatic environments. To
ensure efficient and reliable performance, the drilling equipment is designed to withstand the pressures and
corrosive nature of seawater. Once the desired depth is reached, underwater blasting is utilized to break the rock
or seabed. The primary objective of blasting is to loosen the substrate and create a cavity for subsequent
operations. Safety is a crucial factor in underwater drilling and blasting operations. To safeguard personnel
involved and prevent accidents during drilling and blasting activities, strict safety measures are implemented. In
addition to human safety, precautions are taken to minimize the environmental impacts of underwater drilling
and blasting, including measures to prevent pollution, protect marine life, and preserve the underwater
ecosystem. In this article, the core elements of underwater drilling and blasting operations are outlined. Despite
notable progress in this domain, the paper highlights the enduring constraints and obstacles, underscoring the
need for continued investigation and understanding
Unveiling the petrographical, palynological, palynofacies and geochemical archives of coal and shaly coal deposits in the Mandakini–B block of Talcher Basin: An insight into the paleoecology, depositional environment, kerogen type and source rock potential
No full textCoal and shaly coal beds in the Talcher-Mahanadi Basin, eastern India, belongs to Barakar Formation (Artinskian). A comprehensive analysis was undertaken, including organic petrography, palynology, palynofacies, proximate analysis, Rock-Eval pyrolysis and Field Emission Scanning Electron Microscopy (FE-SEM). The samples consist of the vitrinite group of macerals (avg. 38.2 vol.%), followed by inertinite and liptinite, suggesting peat-forming higher plant vegetation was deposited under prevailing anaerobic conditions. However, the significant presence of inertinite macerals (avg. 29.2 vol.%), including semifusinite and fusinite, along with opaque phytoclasts (avg. 17.3 %), implies occasional shift to oxic conditions. High occurrence of tissue-derived phytoclasts (avg. 64.3 %) indicates that higher plants were the primary contributors to peat formation. Detrovitrinite sub-groups and non-biostructure phytoclasts suggests contributions from herbaceous flora and/or potential tissue degradation due to microbial activity. The palynomorph distribution reveals the dominance of Glossoptriadales, followed by Coniferales and trilete spore groups, comprising 25 genera and 40 species. Non-striate bisaccate pollen, primarily Scheuringipollenites (15–34 %) and sub-dominant striate bisaccate pollen Faunipollenites (11–18 %) prevail in the palynoassemblage. Petrographic indices suggest that the deposition of peat-forming telmatic vegetation has largely occurred in wet forest swamp conditions within the mesotrophic hydrological setting. Palynofacies data, plotted on Tyson’s APP (Amorphous organic matter-Phytoclast-Palynomorph) ternary diagram, suggests suboxic to dysoxic deposition conditions. Low phytoclast preservation index (PPI) indicate proximal deposition of the organic matter. Vitrinite reflectance (VRo%) ranged between 0.42 and 0.68 %, suggesting that the coalification reached up to ‘Medium rank D’ or Bituminous D stage. The substantial total organic contents (TOC: 34.02–61.84 wt.%), hydrogen index (HI) (avg. 154 mg HC/gTOC) and dominance of vitrinite maceral/non-opaque phytoclasts indicate Kerogen Type III and have significant potential for gaseous hydrocarbon generation. FE-SEM images reveal well-developed intergranular and organic pores within the matrix system, serving as both a source and storage in coal beds
Coal quality enhancement by using bio extracts of carissa carandas fruits in combination with Hydro Fluoric acid
No full textThis paper addresses the imperative need for environmentally sustainable beneficiation technologies tailored for low-rank coals, constituting about 50% of global coal deposits. The focus is on recent advancements in bio-beneficiation methods for sub-bituminous coals in thermal power stations, employing ”bio extract of Carissa carandas fruits” with lower concentrations of Hydrofluoric acid. The objective is to enhance coal quality by reducing ash content and adjusting mineral composition to mitigate clinker formation during combustion. The research investigates simultaneous coal treatment with bio extract and low-concentration Hydrofluoric acid. While traditional beneficiation techniques, such as physical, chemical, and physicochemical methods, have been extensively used, a research gap is identified in green methods utilizing biomaterial extracts to remove/reduce metal oxides from coal and the need to regulate the silica-to-alumina ratio in coal composition, for resolving the issue of clinker formation. The investigation demonstrates the bio extract’s efficacy in leaching alumina, iron oxide, and alkali/alkaline earth metal oxides from coal, significantly reducing ash content. Consequently, there is a remarkable increase in coal’s gross calorific value post bio-beneficiation, accompanied by a significant reduction in sulfur content in addition to the decrease in tendency of clinker formation of coal during combustion. This study is a significant contribution to the field of environmentally friendly coal beneficiation and to reduce the tendency of clinker formation during combustion
Groundwater Geochemical Investigation and Quality Assessment for Drinking and Irrigation Uses in Sohagpur Coalfield, Madhya Pradesh, India
No full textThe present investigation aims to assess the processes controlling the composition of groundwater in the Sohagpur coalfield and its quality concerning drinking and irrigation purposes using hydrogeochemical and statistical approaches, water quality indices, and a geographic information system (GIS). Twenty-seven groundwater samples collected from different sites were analysed for electrical conductivity (EC), pH, turbidity, major anions and cations, total dissolved solids (TDS), and total hardness (TH). The study results show that the pH of samples varied from 5.97 to 8.26, suggesting the acidic to slightly alkaline nature of the water samples. The TDS ranged from 265 to 1450 mg/L with 78% of the samples being in the freshwater category. The Ca2+-Mg2+-SO42− and Ca2+-Mg2+-HCO3− are dominant hydrogeochemical facies in the Sohagpur coalfield. The hydrogeochemical and statistical methods show that the groundwater chemistry of the Sohagpur coalfield is primarily controlled by the dissolution and weathering of minerals and secondarily due to the influence of anthropogenic activities (i.e., agricultural practices, sewage, and animal waste discharge). In the majority of the groundwater samples, concentrations of TH, TDS, turbidity, and SO42− exceeded the Bureau of Indian Standards (BIS) drinking acceptable limits and suggested that water is unsuitable for direct consumption. Moreover, the estimated water quality index (WQI) indicated that 52% of the samples (especially from the Dhanpuri and Amlai areas) belong to poor to unfit water categories. High values of EC in 56% of the samples and magnesium hazard (MH) at two sites restrict the irrigation suitability at these locations
CO2 Storage Potential of Coaly Shales of the Barakar Formation in the Rajmahal Basin, India
No full textCoaly shale layers are frequently found in most basins around the world, but less is known about their CO2 sequestration and shale gas potential. To fill this knowledge gap, the mineralogy, geochemical, and pore structure properties of 12 coaly shale samples collected from the Barakar Formation within the Rajmahal Basin in India were examined by XRD analysis, programmed pyrolysis, and low-pressure nitrogen (N2) and carbon dioxide (CO2) adsorption, respectively. The results showed that the samples are organic rich, with 3.05 to 33.92 wt % total organic carbon (TOC). Moreover, Rock-Eval pyrolysis revealed the abundance of gas-prone kerogen type III in these coaly shales, with temperature of maximum pyrolysis yield (Tmax) values between 422 and 446 °C, indicative of an immature to early maturity stage. N2 adsorption experiments showed that samples’ BET-specific surface areas (BET-SSA) vary from 8.47 to 32.4 m2/g, and pores are generally between 20 and 23 nm. However, the CO2 adsorption measurements suggested that the samples’ DFT surface area is 23.064 to 108.3 m2/g. The D–A pore diameter was found to range from 1.31 to 1.71 nm, and the DFT micro-PSD indicated substantial peaks for pores smaller than 0.6 nm in all samples. The adsorbed CO2 volume also ranged between 2.06 and 10.30 cm3/g. According to the fractal analysis, a higher pore structure complexity of the samples compared to their pore surface roughness was observed. Overall, although the investigated coaly shales had favorable geochemical and petrophysical characteristics as shale gas resources, the thermal maturity of the organic matter suggests low volumes of generated gas. On the contrary, the ideal microporous characteristics, including the high micropore surface areas and the existence of pores below 1 nm, as well as large CO2 adsorption quantities that originate from high amounts of organic matter content and their coaly nature, could recommend their great potential for storing CO2. Accordingly, further and supplementary investigations in the region are recommended to gain more information regarding the CO2 storage capacity in the Barakar Formation
Spatial distribution, source apportionment, and health risks assessment of trace elements in pre- and post-monsoon soils in the coal-mining region of North Karanpura basin, India
No full textCoal mining activities in the North Karanpura basin have significantly increased the trace element (TE) concentrations in the soil, resulting in soil pollution and potential health risks. To assess this, 113 soil samples, along with coal, shale, and overburden rocks, were collected from open-cast mining areas during pre-monsoon (Pre-M) and post-monsoon (Post-M) seasons. Seasonal analysis revealed higher TE concentrations in the Post-M period, especially in the SE direction, followed by NE and NW, likely due to surface runoff and deposition, demonstrating temporal variability in TE distribution which corroborated from the spatial distribution maps. Positive matrix factorization (PMF) model identified four factors: mixed sources (F1Pre-M: 37.6 %; F4Post-M: 28.9 %), coal-fired emissions (F2Pre-M: 20.5 %; F3Post-M: 26.0 %), overburden rocks (F3Pre-M: 25.5 %; F2Post-M: 16.7 %), and agricultural and lithogenic origin (F4Pre-M: 16.4 %) during the Pre-M period, attributed to coal mining. Post-M sources were similar, but agricultural and lithogenic origins were replaced by atmospheric deposition (F1Post-M: 28.4 %), enhanced by monsoon effects. Carcinogenic risk assessment revealed that As, Cr, and Ni exceeded acceptable levels for children via ingestion, though adults remained within safe limits. Inhalation and dermal contact were also considered, but ingestion posed the highest risk. The hazard index (HI) via ingestion showed that children had an HI of 1.6 in Pre-M, increasing to 2.66 in Post-M, highlighting their potential vulnerability to non-carcinogenic risks, while adults stayed within safe limits. The expansion of mining areas in the study region led to decrease in vegetative areas which could affect agriculture and local communities, raising a comprehensive environmental and public health issues. These results underline the need for implementing effective biannual soil monitoring and mitigation strategies, such as phytoremediation, bioremediation, rock dust remediation, chemical amendments and improved waste management, to reduce TE contamination
Depositional environmental controls on mechanical stratigraphy of Barakar Shales in Rajmahal Basin, India
No full textUnderstanding mechanical behaviour of shale is essential for efficient shale gas extraction, which can vary in different depositional settings. The impact of sedimentary environment on shale characteristics, such as mineralogical composition, total organic carbon content (TOC), and petrophysical properties, has been extensively researched. However, its influence on shale mechanical properties, especially in defining mechanical stratigraphy for targeting specific fracturing intervals, remains less explored. In this study, the influence of depositional environment on the mechanical properties of shale samples from the Rajmahal Basin is evaluated. Tensile strength of the samples was measured by the Brazilian splitting tensile strength and the brittleness index was calculated as a measure of mechanical properties. In addition, inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray fluorescence spectroscopy (XRF), Rock-Eval 6, and X-ray diffraction (XRD) analysis were carried out to assess geochemical characteristics of the samples from different perspectives. The results revealed that such geochemical variations that are generally controlled by the depositional environment, would impact the mechanical properties of the samples. Based on major and trace elements proxies, the depositional environment was determined to be passive continental margin, with hot and humid paleoclimatic conditions and freshwater anoxic settings. Tensile strength and brittleness index of the shale samples was observed to vary between 0.93 and 4.12 MPa and 0.71 to 3.40, respectively, while samples with the TOC exceeding 15 wt% had a strong negative correlation with tensile strength, as reasonably expected, due to weakening impact of the sedimentary organic matter on the shale matrix. Tensile strength and brittleness index correlated positively with clay mineral content, particularly their type, but negatively with the quartz content. Furthermore, samples abundant in biogenic silica exhibited reduced brittleness compared to those with lithogenic silica. Nevertheless, the variation in mechanical properties with burial depth was not substantial, and the examination of stress-strain curves indicated an overall brittle nature of the layer where the samples were retrieved from. Overall, achieving more robust conclusions regarding mechanical stratigraphy within the studied section of the Rajmahal Basin, would necessitate additional vertical sampling
A Scientific Exploration of Blast-Induced Ground Vibration Mitigation Strategies for Sustainable Coal Mining in India
No full textMining operations in close proximity to dwellings and sensitive structures present challenges in terms of mitigating the undesirable effects of blasting while maintaining productivity and ensuring the safety of surrounding communities. This paper explores the application of advanced blasting techniques, including the use of electronic detonators and the splitting of total explosive charges, to address these challenges. A series of experimental blasts were conducted, comparing blasts conducted with and without splitting of holes, to assess the impact on ground vibrations. The results demonstrated significant reductions in vibration magnitudes when implementing controlled blasting practices with splitting techniques. The findings highlight the importance of total explosive charge in determining ground vibration magnitudes within the danger zone of mine workings. The use of electronic detonators provided precise control over blast sequencing, contributing to safer and more efficient mining practices. These advanced blasting methods offer a practical and innovative solution for conducting safe mining operations near dwellings and sensitive structures, ensuring compliance with safety regulations while sustaining productivity
Scientific Study on Assessment and Mitigation of Ground Vibration Induced by Heavy Earth Moving Machineries Used during Construction Works of Shree Mandir Parikrama Project, Puri, Orissa
No full textShree Mandir Parikrama Project (SMPP), Puri is an ambitious project of Govt of Orissa under its Augmentation of Basic Amenities and Development of Heritage and Architecture (ABADHA) Scheme for developing Puri as “World Class Heritage City”. The project is planned to provide essential amenities to the tourist, an opportunity to develop and give modern architectural design to the heritage structure and various Math around the temple and also protect the monument of vehicular pollution. A study to evaluate the critical impact of ground vibration induced by Heavy Earth Moving Machineries (HEMM) operational during various construction activities of SMPP Project was carried out as by CSIR-CIMFR Regional Research Centre Bilaspur. Comprehensive investigation has been carried out in different phases to analyze attenuation characteristics of ground vibration induced by HEMM and its associated cumulative impact on the various structures of Shree Jagannath Temple. Various combinations of HEMM such as Rock Breaker (120 Ton), Rock ripper, and high capacity Hydraulic Excavator etc. were made operational individually and collectively to measure the induced vibration and frequency using advanced seismograms. Vibration monitoring was also carried out at various critical structures of temple to assess likely damage due to amplification in the induced vibration under different permutation and combination of HEMMs operations. The attenuation characteristics of observed vibration data in different experimental conditions have been analyzed and compared with the widely-accepted vibration standards. The observed vibration data were analyzed and it was found that the vibration values induced by the construction equipment used in SMPP site, Puri were significantly less than the permissible safe limit of 2.0 mm/s. All the observed vibration values were lower than 1.0 mm/s barring few readings of cumulative operation observed at distance of approximately 3.0 m. Vibration reduces to less than 0.250 mm/s beyond a distance of 8.0 m. Faster decay of vibration may be attributed to the geological set-up of the site which is primarily sandy soil and gravel
Fischer–Tropsch Conversion of H2 Lean Syngas Over Mesoporous Silica–Carbon Composite Supported and Cu Promoted Fe Catalysts
No full textIron based Fischer–Tropsch (FT) catalysts have widely been used for liquid hydrocarbon synthesis by using syn gas (CO + H2) as a reactant. The water gas shift activity of iron makes it a potential catalyst for liquid hydrocarbon synthesis by using H2 deficient syngas a reactant. Despite numerous studies on supported iron-based catalysts, there is still room for improvement in our understanding of the specifics of supported iron-based catalysts for FT reactions. The aim of the present study was to explore the role of mesoporous silica–carbon composite (SCn) materials as a support for development of iron based FT catalyst. SCn material was synthesized with different carbon/silica (C/Si) mole ratio. The high surface area, ordered mesoporosity and narrow pore size distributions of SCn material made it a potential support material for development of iron based FT catalyst which facilitated the diffusion of reactant gas molecule inside the mesoporous channel of catalyst. The cylindrical mesoporous channel itself acted as a nanoreactor which facilitate conversion of syn gas to liquid hydrocarbon. The copper promotion also played synergistic role by decreasing the reduction temperature of iron species as well as water gas shift (WGS) activity. The carbon containing support material also played promoting role for iron based FT catalyst. Presence of copper and carbon reduced the reduction temperature of iron species as well as growth of active metal species. Besides, carbon also reduced the formation of silica-iron complex which increased the active catalytic site. This study may boost the development of iron based catalyst for pilot scale study of FT reaction