IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Development of simplified WQIs for assessment of spatial and temporal variations of surface water quality in upper Damodar river basin, eastern India
No full textIn this study, four surface water quality datasets of upper Damodar river basin (DRB) covering three seasons; pre-monsoon, monsoon, post-monsoon and annual, for years 2007–2010 were generated by analyzing 280 grab water samples. Each dataset consist of water quality constituents of 35 monitoring stations and sample of each station was evaluated by 17 critical parameters (total 4760 observations). Furthermore, each dataset was treated using six water quality indices (WQIs): four developed simplified indices (WQIm, WQImin, WQIDO, and WQIpca) and two existing extended indices (WQIobj and WQIsub), to assess spatiotemporal variations and suitability for human use and aquatic life. Results revealed that developed indices show on an average similar spatiotemporal variations as compared to WQIobj at a lower analytical cost at most of sampling sites comes under good to medium categories of water quality. Geographical information system (GIS) technique was also used for generation of temporal pollution potential maps of DRB. Consequently, this study also presents the necessity and usefulness of developed indices over extended indices especially for the developing countries, because the cost of monitoring and expenses associated with the implementation is less compared to extended methods and generated maps may also facilitate the decision-making processes under various scenarios considering spatial and temporal variability in DRB
Optimization of surfactant-aided coarse coal dewatering process in a pilot-scale centrifuge
No full textWater is a scarce and critical resource for the mineral processing industriesand the recycling of the water recovered from different unit operations is possibly the best way to ensure the continued operation of the plants throughout the year. Moreover, the reduction in the product moisture content reduces the cost of transportation and drastically reduces the handling problems. In the present work, the dewatering efficiency of the coarse coal (−13+0.5mm) in a pilot-scale vibratory basket centrifuge was measured and enhanced using surfactants as the dewatering aids, followed by the optimization using statistical analysis. The experiments were conducted considering three variables, i.e. feed rate, feed moisture content and surfactant concentration, using a full factorial design of the experiments. Experimental results were analysed with the help of a statistical software package (Statistica). Regression equations were developed to show the effect of each parameter and their interactions on the residual moisture content. The statistical model developed for the dewatering of coarse coal, using the three variables, was tested and was found to predict the moisture content of product coal with an average error of 5%
Characterization of lead–zinc mill tailings, fly ash and their mixtures for paste backfilling in underground metalliferous mines
No full textSurface disposal of mill tailings and fly ash is a major concern for many countries, as it pollutes the environment including air, water, and soil. Paste backfilling is an emerging mine backfilling technique, wherein the industrial wastes such as mill tailings, fly ash and blast furnace slag are backfilled inside the stopes. This study examines the physico-chemical characteristics of lead–zinc mill tailings, fly ash and their mixtures for their possible utilization in paste backfilling in underground metalliferous mines. Three different mill tailing–fly ash mixtures, viz., 95:5, 92:8 and 90:10 (wt%), have been considered. The chemical, morphological and mineralogical compositions are analyzed by XRF, SEM and XRD. The morphological analysis revealed that the mill tailings are irregular in shape and fly ash particles are almost spherical in nature. The filling of inter-particle spaces of irregular mill tailings with spherical fly ash and finer mill tailings (− 20 µm) particles will enhance the rheology of mill tailing–fly ash mix paste backfill. Chemically, the lead–zinc mill tailings is enriched in SiO2, CaO, Fe2O3, and Al2O3, whereas fly ash is mainly composed of SiO2 and Al2O3 with small amounts of Fe2O3, CaO, K2O, TiO2, MgO, SO3, Na2O, and P2O5. The XRD analysis revealed that the lead–zinc mill tailings mainly contain quartz, pyrite, dolomite, hematite and calcite, while fly ash contains quartz, mullite, kaolinite and hematite. This study proved that lead–zinc mill tailings and fly ash together can be suitably used for paste backfilling in underground metalliferous mines
The influence of the thermal aureole asymmetry on hydrocarbon generative potential of coal beds: Insights from Raniganj Basin, West Bengal, India
No full textThe aim of the present study is to uncover hydrocarbon generation potential of an area intruded by lamprophyre dyke. Lamprophyre dyke induced a short-distance asymmetric thermal aureole in coal beds with more intense impact along the dip direction. Large ash yield, carbon content, lower volatile matter content, hydrogen indices, presence of natural coke, disordered kaolinite peaks, less pronounced aliphatic peaks, higher aromaticity under Fourier Transform Infra-Red spectroscopy (FTIR); highly rugged surface and large pores with the aid of Atomic force microscopy (AFM); abundant calcium carbonate mineral phases (calcite, dolomite, ankerite) and high-temperature silica phases (tridymite, sanidine) under X-ray diffraction (XRD) are the consequences of pronounced thermal effect and expulsion of hydrocarbons. Furthermore, the estimated vitrinite reflectance (EVRo) calculated through maximum pyrolysis temperature (Tmax) and measured mean random vitrinite reflectance (VRo) show the maximum difference in the heat-affected coal samples. In addition, parameters for source rock reconstruction and indices for quantification of FTIR spectra i.e. index of aliphaticity (IAL), index of aromaticity (IAR) and index for hydrocarbon generation (IHG) are introduced for coals. The distant (i.e. least-heat-affected) coals collected opposite to the dip direction of the coal bed have a higher potential for hydrocarbon generation. The igneous intrusion thus played a significant role in enhancing the maturity of the organic material, in turn, augmenting the hydrocarbon generation potential for targeting hydrocarbon plays of the area although at the expense of proximal samples
Laboratory and pilot plant flotation studies on settling pond coking coal fines and its utilization for metallurgical purposes
No full textMost of the Indian coking coal washeries were installed during the period 1960-1980 where the design of the washery was based on relatively easy or moderately difficult washing coking coals, mined in the eastern and western part of Jharia coalfields. The coal fines below 0.5 mm were not processed and though enriched in vitrinite content, nowadays the fines cannot be mixed directly with clean coal due to their high ash content (more than 25%) and of high percentage of silica content.
Due to an increase in opencast mechanized mining of coals, quality of the coal fines deteriorated and they need to be beneficiated before blending with the coarse coals. Some of the washeries installed fine coal treatment plants, but due to varied reasons these circuits were not operated as a result, huge quantity of unwashed coal fines is left as such and discharged to nearby ponds or lagoons, and in the process they had been accumulated in adjoining settling ponds causing environmental pollution and are being sold to domestic market for use in non-metallurgical purposes.
The coking coal fines constitute vitrinite content, which is a vital ingredient for metallurgical purpose. Hence, if these coal fines are beneficiated, they may add to the overall quality of the clean coal. In this paper attempt has been made to beneficiate the accumulated coal fines through laboratory flotation tests vis-à-vis pilot plant studies to generate maximum amount of cleans from settling pond coal fines suitable as blend for metallurgical coke making
Multivariate statistical analysis approach for prediction of blast-induced ground vibration
No full textExcavation of coal, overburden, and mineral deposits by blasting is dominant over the globe to date, although there are certain undesirable effects of blasting which need to be controlled. Blast-induced vibration is one of the major concerns for blast designers as it may lead to structural damage. The empirical method for prediction of blast-induced vibration has been adopted by many researchers in the form of predictor equations. Predictor equations are site specific and indirectly related to physicomechanical and geological properties of rock mass as blast-induced ground vibration is a function of various controllable and uncontrollable parameters. Rock parameters for blasting face and propagation media for blast vibration waves are uncontrollable parameters, whereas blast design parameters like hole diameter, hole depth, column length of explosive charge, total number of blast holes, burden, spacing, explosive charge per delay, total explosive charge in a blasting round, and initiation system are controllable parameters. Optimization of blast design parameters is based on site condition and availability of equipment. Most of the smaller mines have predesigned blasting parameters except explosive charge per delay, total explosive charge, and distance of blast face from surface structures. However, larger opencast mines have variations in blast design parameters for different benches based on strata condition: Multivariate predictor equation is necessary in such case. This paper deals with a case study to establish multivariate predictor equation for Moher and Moher Amlohri Extension opencast mine of India. The multivariate statistical regression approach to establish linear and logarithmic scale relation between variables to predict peak particle velocity (PPV) has been used for this purpose. Blast design has been proposed based on established multivariate regression equation to optimize blast design parameters keeping PPV within legislative limits
Spatio-temporal variations of respirable particles at residential areas located in the vicinity of opencast coal projects, India: a case study
No full textThe objective of the study is to investigate spatio-temporal variations of PM10, PM2.5, and PM1concentrations at seven residential sites, located in the vicinity of opencast coal projects, Basundhara Garjanbahal Area (BGA), India. Meteorological parameters such as wind speed, wind direction, relative humidity, and temperature were collected simultaneously with PM concentrations. Mean concentrations of PM10 in the range 215 ± 169–526 ± 412 μg m−3, PM2.5in the range of 91 ± 79–297 ± 107 μg m−3, PM1 in the range of 68 ± 60–247 ± 84 μg m−3 were obtained. Coarse fractions (PM2.5–10) varied from 27 to 58% whereas fine fractions (PM1–2.5and PM1) varied in the range of 51–73%. PM2.5 concentration was 41–74% of PM10concentration, PM1 concentration was 31–62% of PM10 concentration, and PM1 concentration was 73–83% of PM2.5 concentration. Role of meteorology on PM concentrations was assessed using correlation analysis. Linear relationships were established among PM concentrations using least square regression analysis. With the aid of principal component analysis, two components were drawn out of eight variables, which represent more than 75% of variance. The results indicated that major sources of air pollutants (PM10, PM2.5, PM1, CO, CO2) at the residential sites are road dust raised by vehicular movement, spillage of coal generated during transportation, spontaneous combustion of coal, and biomass burning in village area
INVESTIGATION OF COAL-METHANOARCHAEAL ASSEMBLAGE IN DEEP SUBSURFACEUNDERGROUND USING ENRICHMENT CULTURE TECHNIQUE
No full textEnrichment culture of coal samples from underground mines (Jitpur and Moonidih underground mines) located in Dhanbad region, the Indian state of Jharkhand was tested positive for the presence of living microbial lineage capable of producing methane from coal during energy metabolism under laboratory condition. Accordingly, two gram negative, mesophilic, penicillin G and streptomycin resistant strain (BC /C IMFR-ana-CH4-12 and 14) derived from preferred sites were produce methane from acetate. They assimilated complex proteinaceous substances (yeast extract, beef extract, tryptone, and peptone) and amino acids (alanine, cysteine, and methionine) for energy metabolism. The pH ranges for growth were 6.0-7.5 for strain BC /C IMFR-ana-CH4-12 and 6.5-8.5 for strain BC /C IMFR-ana-CH4-14, with the fastest growth at pH 7.5 for BC /C IMFR-ana-CH4-12 and pH 7.0 for strain BC /C IMFR-ana-CH4-14. During growth, doubling time was observed 13.702- 14.005 hours under the optimal condition, and specific growth rate was recorded 0.021/hour for both strains. Based on the study strains were belongs to Methanococcus spp. and Methanobacterium spp., associated with numerous aerobic and anaerobic microbial community in deep subsurface coal deposits as suitable habitat. The ecological implication of their habitat also discussed. The study suggests that there is intense biogenic methane generation activity in a selected environment which may me enhance by stimulating the activity of existing methanoarchaeal consortia
Estimation of rock load in development workings of underground coal mines – a modified RMR approach
No full textUnderground coal mining in India contributes to a share of 55 Mt production with more than 500 mines in operation. In spite of using the well-established CMRI-ISM Rock Mass Rating (RMRdyn) classification system for roof support design successfully in Indian geo-mining conditions, accidents due to roof fall constitute the major challenge. These failures are generally due to the presence of weak beddings and laminations. Seismic refraction technique (for shallow depth) can be useful in detecting the rock mass conditions. Based on the study a modified rock mass classification system (RMRdyn) was setup by incorporating field P-wave velocity with a view to arrive at a real ground condition of the in situ rock. Rock loads were also determined in the field to develop a relation with RMRdyn. A comparison of rock load estimation by CMRI-ISM RMR, numerical simulation and RMRdyn clearly depicts that the latter approach is more reliable as the results are close to the actual scenario
Gasification of coal and press mud blends in fluidized bed gasifier
No full textIn line with the clean-energy development program in India an attempt has been made towards utilisation of press mud, a sugar industry waste product, through co-gasification with high-ash coal. Gasification was conducted with the mixture of air and steam at a temperature 1,223 K under atmospheric pressure in a pilot scale fluidised bed gasifier. The operating system and conditions did not allow to increase the press mud content in blends beyond 40 mass %. However, the operations with 10-40% press mud content were successful without the formation of tar or any agglomerate and proper fluidisation was achieved with smooth and controlled variations of temperature, air flow, steam flow rate, etc. In the case of co-gasification of the aforesaid blends, process parameters were identified and operational philosophy was established to improve the overall carbon conversion and other performance parameters over respective coal gasification performance