IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Assessment of Seasonal and Site-Speci�c Variations in Soil Physical,Chemical and Biological Properties Around Opencast Coal Mines
Get PDFCoal mining adversely affects soil quality around opencast mines. Therefore, a study was conducted in 2010 and 2011 to assess seasonal and site-specific variations in physical, chemical, and biological properties of soil collected at different distances from mining areas in the Jharia coalfield, India. Throughout the year, the soil in sites near coal mines had a significantly higher bulk density, temperature, electrical conductivity, and sulfate and heavy metal contents and a significantly lower water-holding capacity, porosity, moisture content, pH, and total nitrogen and available phosphorus contents, compared with the soil collected far from the mines.
However, biological properties were site-specific and seasonal. Soil microbial biomass carbon (MBC) and nitrogen (MBN), MBC/MBN,and soil respiration were the highest during the rainy season and the lowest in summer, with the minimum values in the soil near coal mines. A soil quality index revealed a significant effect of heavy metal content on soil biological properties in the coal mining areas
Responses of Tropical and Subtropical Plants to Air Pollution
Get PDFThe tropical and subtropical regions of the world are facing strong negative
effects of globalization, weakening the critical balance between ecosystem stability
and socioeconomic development. Apart from increasing pressures of global
climate change, deforestation, and shifts in land use pattern, air pollution is
emerging as one of the major factors influencing ecosystem structure and function.
Issues related to health, agricultural production, and economic losses due to
air pollution in the tropical and subtropical regions are well known; however,
information on air pollution-related effects on the tropical vegetation is limited.
Therefore, based on the current literature, the status of air pollution and its effects
on vegetation in the tropical and subtropical regions of the globe are explored in
this chapter to understand the current scenario and to identify the knowledge
gaps. Spatial and temporal variations were detected among different regions for
particulate matter, its constituents, and gaseous pollutants including identification
of the factors and sources influencing the air quality. Air pollution impacts
were assessed based on changes in ecosystem structure and functions such as the
patterns of biodiversity change, alteration in litterfall and decomposition, the
response of leaf functional traits, and bioaccumulation in the community or individual
plant species. Air pollution significantly influenced major ecological processes
such as litterfall, decomposition, and plant diversity indirectly through
changes in soil quality as well as through a direct effect on growth and physio
Establishing fluidization parameters of different size of coal ash particles in bubbling fluidized bed
No full texthe Fluidization behavior of coal ash particles was studied to establish fluidization parameters in a cylindrical bubbling fluidized bed. A series of experiments were carried out with different sizes of irregular coal ash particles ranging from 1 mm to 3 mm at different bed heights at atmospheric pressure and room temperature (ca. 28 °C). Fluidization regimes of all selected coal ash particles were studied by varying flow rates of fluidization medium i.e., air. The change in bed height and pressure drop across the bed was carefully analyzed to see the effects of particle size and superficial gas velocity during fluidization. The minimum fluidization velocity (Umf), minimum bubbling velocity (Umb) and fluidization index for different sizes of ash particles in cold conditions were calculated. The validation of experimental values was supported by theoretical calculations. It was observed that the Umb is 1.5–1.8 times higher than the Umf at different bed heights (Hbed). No substantial deviation was found in Umf with the variations of Hbed at a particular mean particle diameter (dp). Finally, the fluidization index between 1.58 and 1.78 for coal ash particles of Geldart-D type (dp> 1000 µm) shows an ideal condition for fluidization
Screening potential plant species for arresting particulates in Jharia coalfield, India
No full textMining and related activities cause severe degradation of ambient air quality. A study of particulate matter (PM) across transportation, mining and control (C) sites for dust attenuation capacity (DAC) in selected tree species were carried out in Jharia coalfield (JCF) to estimate the menace of dust pollution and also to measure air pollution tolerance index (APTI). Results indicated that the maximum value of PM10 and PM2.5 ranged from 54 to 174 and 29 to 78 μg m− 3 respectively across all the sites. The maximum values occurred in transportation and the minimum at C for both the particulates. Mining and transportation resulted in an increase in PM10 values by 161 and 200% and PM2.5 values by 100 and 136% respectively as compared to those in C. The mean concentration of PM10 and PM2.5 across the sites exceeded the permissible limit of 100 and 60 μg m− 3 respectively. Transportation was worse than mining due to the high proportion of hazardous fine (PM2.5) particulates. DAC indicated that Tectona grandis (TG) captured maximum dust (2.15 mg cm− 2 ) with 85% and Peltophorum inerme (PI) the minimum (0.15 mg cm− 2 ) with 5% efficiency. The trend for DAC showed TG > Ficus glomerata (FG) > Psidium guajava (PG) > Ficus benghalensis (FB) > Ficus religiosa (FR) > Alstonia scholaris (AS) > Aegle marmelos (AM) > Gmelina arborea (GA) > Dalbergia sissoo (DS) > Syzyzium cumini (SC) > Azadirachta indica (AI) > Terminalia arjuna (TA) > Mangifera indica (MI) > Albizia lebbeck (AL) > PI in descending order. APTI based on pH, total chlorophyll, ascorbic acid and relative water content indicated maximum values for TG (17) with 90% and minimum for PI (10) with 57% of the total and is a measure of the sustainability of plants in JCF. The descending order for APTI was TG > PG > FG > FR > FB > AI > MI > SC > DS > GA > AM > AS > AL > TA > PI. Thus, TG is the most suitable and PI the least. Stomatal density is negatively related to DAC and positively related to APTI. DAC therefore, cannot be attributed to a single factor but a mix of complex factors such as morphological and anatomical characteristics of the leaf, particle size, species type, metabolism, location, meteorology and stress conditions. Based on the findings a greenbelt design was proposed to improve the air quality of the mining and transportation areas
Generalised Analytical Models for the Strength of the Inclined as well as the Flat Coal Pillars using Rock Mass Failure Criterion
No full textThe assessment of the strength of the coal pillars is essential for the safe extraction of the coal seam. All the pillar strength formulae used worldwide are developed for the flat coal pillars. Therefore, their adoption in evaluating the strength of the inclined coal pillars may endanger the workings of the inclined coal seams. The strength of an inclined coal pillar should be estimated by considering the inclination of the coal seam and its associated behaviour, because the shearing effect along the true dip aggravates the instability of the inclined coal pillars. In this paper, generalised analytical solutions have been developed to estimate the strength of the coal pillars which can be applied for both the inclined and flat coal pillars. The mathematical models are derived to obtain the confining stress in the coal pillar and the corresponding peak stress at the time of its failure using a rock mass failure criterion. The mathematical expressions are also developed for the stress distribution over the pillar considering the increase of the shearing effect with the dip of the coal seam. The Mohr–Coulomb criterion is considered for the shear characteristics at the interfaces of pillar–floor and pillar–roof. The asymmetrical stress distribution and failure along the dip-rise and the strike directions of the inclined coal pillars are addressed in this study. The concept of the confined core and three-dimensional stress distribution over the coal pillar are used to derive the strength formulae for the square, rectangular, and very long pillars. The performance of the derived strength formulae is assessed by the stable and failed cases of the flat and the inclined coal pillars. It is observed that all the inclined and flat coal pillars cases are correctly predicted by the derived generalised strength formulae. According to the derived strength formulae, the strength of the inclined coal pillar decreases with the increase of the inclination of the coal pillar. This paper also describes the variation of the strength of the inclined coal pillars with respect to the coal seam inclinations and the frictional properties of the contact planes for the different width-to-height ratios
Evaluation of bump-proneness of underground coal mines using burst energy coefficient
No full textUnderground exploitation of the deep-seated coal deposits faces a number of problems like coal bumps, pillar squeezes, sudden collapse and floor heaving. Among them, coal bump is one of the most difficult, hazardous and long-standing engineering problems. The bump-proneness of a mine can be used as a safety index and if anyone could identify the bump-proneness of the mine before the commencement of the mining operation, then a suitable safety or risk assessment of the mine can be done. Suitable remedial measures or method of mining can also be implemented to avoid major safety issues like strata control problems. Physical experiments in laboratory and field tests to determine the bump-proneness of a mine is a tedious, expensive and time-consuming process. In this paper, a methodology to evaluate bump-proneness of a mine has been described using Burst Energy Coefficient through numerical modelling along with three case studies, namely Digwadih Colliery of Tata Steel Limited, VK-7 Incline mine of SCCL and Chinakuri mine of ECL. It is found that the Digwadih colliery is not burst-prone up to the depth of 600 m, but it may be moderately burst-prone if the depth of cover of the working is increased to 750 m. Similarly, it is found from the study that the VK-7 Incline mine is not burst-prone up to the depth of cover of 450 m but estimated to be burst-prone at a depth of cover of 600 m. Chinakuri mine is found to be burst-prone for the considered depth of cover of 700 m. It is found that the observed or reported burst-proneness conditions of the mines are well-matching with the burst-proneness index estimated through the numerical modelling. Hence, it can be suggested that the coal bump hazards of mine can be effectively predicted by the burst energy coefficient
Assessment of Seasonal and Site-Specific Variations in Soil Physical, Chemical and Biological Properties Around Opencast Coal Mines
No full textCoal mining adversely affects soil quality around opencast mines. Therefore, a study was conducted in 2010 and 2011 to assess seasonal and site-specific variations in physical, chemical, and biological properties of soil collected at different distances from mining areas in the Jharia coalfield, India. Throughout the year, the soil in sites near coal mines had a significantly higher bulk density, temperature, electrical conductivity, and sulfate and heavy metal contents and a significantly lower water-holding capacity, porosity, moisture content, pH, and total nitrogen and available phosphorus contents, compared with the soil collected far from the mines. However, biological properties were site-specific and seasonal. Soil microbial biomass carbon (MBC) and nitrogen (MBN), MBC/MBN, and soil respiration were the highest during the rainy season and the lowest in summer, with the minimum values in the soil near coal mines. A soil quality index revealed a significant effect of heavy metal content on soil biological properties in the coal mining areas
Interpreting Pore Dimensions in Gas Shales Using a Combination of SEM Imaging, Small-Angle Neutron Scattering, and Low-Pressure Gas Adsorption
No full textPermian shales of Barakar formation in India were investigated to study their pore structure to understand their potential for natural gas production and possible CO2 sequestration. The studied shale samples with variable clay content were of early mature stage and contained low (<2%) total organic carbon. Initially, a combination of small-angle neutron scattering (SANS) and low-pressure gas adsorption (LPGA) was used to identify the pore sizes and fractal dimensions of Indian shales. It was found that the quenched surface density functional theory model in the LPGA method gave better pore size distribution (PSD) estimates over the nonlocal density functional theory model. The micropores and smaller mesopores contribute the most to the total pore volume and the surface area of the studied shale samples. The average pore size decreased with an increase in pore volume. The fractal studies using SANS reveal that all studied shales possess similar fractal dimension despite being different in mineralogy, maturity, and total pore volume. The PSD and its possible relation with the mineral composition and the accessibility of the pores in terms of gas storage have been elucidated. Pore morphology was analyzed using image analysis of field emission scanning electron microscopy and low-pressure adsorption, corroborated by SANS results. The effects of dissolution and deposition probability on the fractal dimension of the shale were interpreted using the Monte Carlo-based computer modeling. The fractal dimension was higher in the case of shales that underwent simultaneous dissolution and deposition processes
Treatment of Lignite Mine Water with Lignite Fly Ash and Its Zeolite
No full textAs expected, a zeolite formed from lignite fly ash proved to be far more effective in treating the water from the Neyvelli lignite mines than the fly ash itself. Treatment of mine water at different doses with both materials revealed that the zeolite increased the pH from 2.73 to 8.58 and removed most of the hardness, including the Ca and Mg hardness, as well as the acidity from the mine water. In contrast, the fly ash increased the hardness, Ca, Mg, and sulphate in the mine water. The fly ash was partially effective in removing metals like Mn, Ni, Zn, and Cr. In contrast, increased dosing of lignite fly ash zeolite removed 98.6% of the Mn, 99.94% of the Fe, 96.35% of the Ni, 99.30% of the Cu, 19.15% of the Cd, and 100% of the Zn, Pb, and Cr from lignite mine water. The surface of the lignite fly ash particles were initially covered with loosely attached metals that were released in the acidic water, though due to its alkaline nature, it did partially remove the metals from the mine water
Development of dust ignition protected electrically powered forklift truck for combustible dust environment
No full textIndustries dealing with explosive gases and combustible dusts in processing or production are always at higher risk of gas or dust explosion. Purified terephthalic acid (PTA) plant of Indian Oil Corporation Ltd. (IOCL), Panipat, India has similar risk of dust explosion hazard, since PTA is a combustible substance in the form of dust or layer. To load, unload and transport the PTA bags in the plant, special forklift trucks are required. A prototype forklift truck for combustible dust atmosphere was developed in collaboration with M/s Action Construction Equipment Ltd. (ACE), Palwal, India. The electrical components with dust ignition protected design have been manufactured by ACE in consultation with CSIR-CIMFR, Dhanbad, India. All other possible sources of ignition are identified and suitable components/parts of forklift are used for hazardous atmosphere. This paper presents the design requirements of a dust ignition protected and battery operated forklift truck for safe use in zone 22 combustible dust atmosphere of the plant