IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Blast vibration dependence on total explosives weight in open-pit blasting
Get PDFIt is well established that the blast design parameters, namely explosives weight per delay, distance between the blast site and monitoring location, delay interval, total explosives detonated in a blasting round, velocity of detonation (VOD) of explosives, burden, spacing, explosive column length, top stemming length, number of decks and their length, transmitting media and its geology, and scattering in the delay time of detonators, influence blast-induced vibrations. A study was conducted to assess the effect of total weight of explosive detonated in the blast in ground on the magnitude of blast vibrations at four big coal open-cast mines in India keeping all the parameters constant as stated above. Accordingly, experimental as well as production blasts were conducted at drag line and shovel benches. The results revealed that the magnitude of blast vibrations was influenced by the total amount of explosive detonated in a blast in ground at shorter distances regardless of maximum explosives weight per delay. This paper describes the result of a study carried out to investigate these effects at open-cast projects in India. The study involved 60 blasts with varying blast designs and 498 vibration data were recorded
Quality and Performance of Permitted Explosives and Detonators used in SCCL Mines in India
No full textBlast performance depends on geo-mechanical properties of rock, detonation properties of explosive
systems and blast design parameters. For a mine having nearly constant geo-mechanical parameters and
have fixed optimized blast pattern, the blast results are very much dependent on the quality of explosive
products. For consistent blast results, quality of explosive should be consistent. Mine management needs
to ensure that performance and quality of an explosive system are the same as that has been predicated
or stated by the supplier. Periodic check of the quality and performance parameters of the explosives and
accessories of different manufacturers collected from the users’ magazines/blasting face serve as a useful
mechanism towards ensuring safety and quality of such products. In this paper, quality evaluation of slurry
and emulsion permitted explosives and permitted detonators of different firms supplied in SCCL were
done at SCCL site and their impact on performances in underground coal mines were observed. Results of
studies on post detonation toxic fumes were also done with the help of Rescue team of SCCL in presence
of CIMFR Scientist which gives the real picture of toxic contents of explosives used in underground coal
mines where working personals are allowed to work after 5 minutes of blasting. Deviations in the quality
of explosive and detonator parameters were found which has direct impact on the underground coal
production in SCCL mines. Based on the results of studies and CIMFR advice, explosive manufacturers
improved the quality of their explosive products time to time aimed for getting desired coal production
safely underground coal mines of SCCL in Indi
Modelling for Air Quality Estimation for a Planned Coal Washery to Control Air Pollution
No full textTasra coal washery has been planned in Tasra block which is located in Jharia coalfield of Jharkhand state in India. In order to predict air pollution impact because of the proposed washery, modelling has been done using fugitive dust model. Dust levels (PM10 and PM2.5) have been assessed both for conditions of controlled and uncontrolled emissions from various sources of the washery. Baseline site specific air quality data (PM10 and PM2.5) of winter season and maximum coal washing capacity of 700 t h−1 have been considered for prediction of air quality in case of worst-case scenario. Based on modelling exercise, it has been predicted that PM10 concentration may increase from 0.058–51.333 and 0.039–17.485 μg m−3 under the conditions of uncontrolled and controlled emissions respectively at the air quality monitoring sites and the selected receptor locations in the nearby vicinity of the proposed washery. Similarly, PM2.5 concentrations may rise from 0.044–16.636 and 0.022–7.219 μg m−3 due to the uncontrolled and controlled emissions respectively. In order to minimize the fugitive dust levels from the washery site, installation of dry fog dust suppression system has been recommended at different dust generating sources in addition to implementation of other dust control measures in and around the coal washery
Insights of CBM Produced Water Composition Influenced by Rock Interaction and Seasonal Variations in Raniganj Coalfield, India
No full textAn investigation has been carried out at Raniganj coalfield for the insights of Coal Bed Methane (CBM) produced water compositional
changes during advancement of methane production including the influence of rock dissolution and water-rock interaction. The high
concentrations of Na and HCO is sourced from multiple geo-controlled activities like dissolution of carbonate minerals, conversion of organic
matter to CO and water-rock interaction processes due to change in pH. The concentration of Cl is relatively stable in produced waters but
HCO concentration varies drastically due to saturation of k-feldspar, kaolinite and auxiliary silicate weathering into clays, ultimately
producing higher concentrations of HCO ions. The F ion seems to be sourced from parent rock granite and its associated minerals like biotite,
amphibole, apatite and fluorite. The high content of TDS is principally contributed by Na and HCO ions, results in high SAR values,
suggesting non-suitability of produced water for irrigation use. The determined water quality index (WQI), indicates non-suitability of produced
water for any use. It is observed that the ion exchange and reverse osmosis can make the produced water drinkable. Moreover, the empirical
sodium bicarbonate ratio (SBR) has been proposed to designate the suitability of produced water for different uses. The results of SBR have been
validated by correlating with the SAR and Kelley's index
Prospective evaluation of hydrocarbon generation potential of Umarsar lignite, India
No full textThe organic richness, thermal maturity, oil generation potential, liquefaction behavior hydrocarbon generation potential and geochemical properties of 12 lignite samples from Umarsar lignite mines of Kutch district, Gujarat, India were investigated. The lignite samples studied shows that they are significantly rich in total organic carbon (TOC) content which varies from 36.92 to 51.99 wt%. Tmax and HI index value show that these thermally immature lignite contains Types II-III and Type III kerogen; which is also anticipated from plot between released hydrocarbon (S2) yield and TOC. The cross plot between HI index and TOC demonstrates that the samples fall in fair oil source. The reflectance value varies from 0.23% to 0.28% and confirm it is immature in nature. The huminite maceral (>70.34%) dominates while liptinite >15.53% and inertinite occur in subordinated amount. High quantity of huminite and liptinite macerals shows its aptness towards liquid and gas hydrocarbon formation. The HI index and H/C values favor significant quality of hydrocarbon (gas and oil) potential
PREDICTING BLAST-INDUCED GROUND VIBRATIONS IN SOME INDIAN TUNNELS USING DECISION TREE
No full textThis study compares three different techniques — decision tree, artificial neural network (ANN) and multivariate regression analysis (MVRA) — for predicting blast-induced ground vibrations in some Indian tunneling projects. The models’ performance was also compared with site-specific conventional predictor equations. A database consisting of 137 vibration records was randomly divided into training and testing sets for model generation. The results indicate that the decision tree is best suited to predicting vibrations. Furthermore, the decision tree suggests that the intensity of near-field ground vibrations is mainly affected by the total charge fired in a round, whereas the intensity of far-field vibrations is governed by maximum charge per delay and charge per hole
Apprehension of Subsidence over Old Workings: A Case Study
No full textAn old and abandoned coal mine working especially at shallow depth leaves the scope to disrupt the surface topography and in turn structures as the concern for pot-hole occurrence always prevails in post-mining areas. thus, acomprehensive understanding of stability of ground is a strategic factor prior to erection of infrastructure over underground old coal mine and hence requires indispensable investigation for safety viewpoint. A methodology has been adopted at Surakachar 3&4 Inclines of south Eastern Coalfields Limited (SECL) to effectively gauge pot-hole occurrence. In addition to gathering geo-mining parameters the study envelops detailed site history, a guideline to show the path for precise evaluation of goal. Possibility of pot-hole has been predicted taking into consideration the bearing parameters viz. depth, uniaxial compressive strength of rock, geological discontinuity and water seepage. The potential zones with reference to rating have been identified and accordingly demarcated the grade of risk. Issue related to erection of heavy infrastructures over the disturbed strata caused be depillaring caved panels has been discussed
Overall equipment effectiveness of shovel dumper operation in opencast mining - A review
No full textComparative evaluation of aquatic biomass feedstocks for energy application and potential for extraction of plant nutrients from their ash
No full textAquatic biomasses have fast growth rate amicable for energy applications. Presence of low melting alkali elements is a major challenge; however they are plant nutrients that enhances the ash utilization potential. The aim of this study was to evaluate aquatic biomasses (Eichornia, Hydrilla, Lemna, and Spirogyra) for potential energy application, and to assess the accumulation of plant nutrients in the ashes obtained at different temperatures (500, 600, 700, 800, and 900 °C). Volatile matter content (wt.% dry basis) was lower in Spirogyra (58.2%) or Hydrilla (56.8%) than Eichornia (68.3%) or Lemna (64.7%), whereas fixed C content (wt. % dry basis) was higher for Eichornia and Lemna (about 11%) and lower for Spirogyra (7.4%) and Hydrilla (1.0%). Carbon content ranged from 25.2 to 37.9%; decreased in the order Eichornia > Lemna > Spirogyra > Hydrilla. Ash content was higher for Hydrilla (42.1%) followed by Spirogyra (34.5%), Lemna (24.0%) and Eichornia (19.9%). FTIR and cluster analysis showed comparable ash characteristics for Eichornia and Lemna; Hydrilla and Spirogyra have typical characteristics. Plant nutrient (except N, and K) contents in the ash increased with increase in temperature. Potassium and phosphorous content was higher in Eichornia and Lemna. Slagging and fouling tendencies could be arranged in the order Hydrilla > Eichornia > Lemna > Spirogyra. Eichornia, Lemna, and Spirogyra feedstock could be used for energy application and the resultant ash has valuable plant nutrients (K and P). Low temperature (600–700 °C) processing is advantageous to conserve plant nutrients in ash