IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Controlled Blasting for Deconstruction of a Railway Bridge Near Sahibganj
No full textSome of the Indian Railway bridges require reconstruction for electrification and expansion of railway tracks. Dismantling of bridge within time schedule in densely populated area requires controlled and pre-planned blasting methodology for safe pulling down of the structure and quick removal of blasted debris for fast restoration of tracks and smooth plying of trains. The three arched railway bridge (Bridge No. 61) located between Sahibganj and Karamtola cases one such example where the bridge was dismantled and the track was restored within 4 h of blasting, though the stipulated block period for demolition and restoration of tracks was 6 h. The 25.48 m long three-arched bridge was drilled and blasted with 225 number of blastholes (32 mm diameter) and 100 kg explosive (25 mm diameter). Length of blastholes varied between 0.5 and 1.8 m with blast geometry of 0.3–0.35 m burden and 0.33 m spacing. This paper deals with the conceptual and theoretical model developed for identification of the key locations for drilling and implementation of the same. It also discusses about the precautionary measures and the drilling pattern adopted for quick demolition and speedy restoration of tracks
Beneficiation studies on high ash Indian coking coal using heavy medium cyclone test rig
No full textHeavy medium coal processing technology has been widely used in coal preparation industries in the world since it is the most accurate and efficient coal preparation process to obtain clean coal with a highest possible yield. Separation of coal and impurities using this technology is based on density differences. Tests were carried out on a 100mm dia heavy medium cyclone test rig treating coal in the size range -6 + 0.5mm. A total of twenty seven experiments were carried out by varying the parameters like vortex finder diameter, spigot diameter and inlet feed pressure for each cyclone dia. The results indicate that for 100mm dia H.M. cyclone it is possible to achieve about 24% clean coal at an ash content of 17.3% from feed ash of 35% at a feed pressure of 0.35 kg/cm2, vortex diameter of 42.5mm and spigot diameter of 28mm
A Review on Biodiesel Production through Heterogeneous Catalysis Route
No full textDepletion of oil reserves, increasing prices of petroleum products, and environmental concerns related to air pollution are the main driving forces for utilizing renewable energy resources to replace fossil fuels. Vegetable oils can be used to produce biodiesel. Biodiesel is obtained by transesterification of vegetable oil with alcohol using homogeneous or heterogeneous catalysts. In the industry, biodiesel is produced by heterogeneous catalysts due to high activity and selectivity, better reusability, reduction in processing steps, and wastes. The catalytic activity of catalysts depends on the strength and type of intrinsic basic or/and acid properties. Biodiesel production using heterogenous catalysts depends on the various reaction parameters such as reaction time, temperature, molar ratio of alcohol to oil, catalyst amount, and stirring speed. In this paper, the catalytic transesterification of various feedstocks such as edible oil, non‐edible oil, and waste using heterogeneous catalysts has been reviewed and optimization parameters for maximum biodiesel production have been summarized
A new approach for indexing groundwater heavy metal pollution
No full textA new approach has been proposed for indexing heavy metal pollution in groundwater based on highest desirable and maximum permissible concentrations. This new approach aims to address various shortcomings of the existing indexing systems. According to the new indexing system, heavy metal pollution status of any water sample may be expressed by a pair of positive index (PI) and negative index (NI). Positive index reflects heavy metal concentration in water exceeding highest desirable limit, while negative index corresponds to heavy metals within desirable limit. Water quality deteriorates with increasing PI and the pristinity increases with decreasing NI. A comprehensive PI and NI scale has been drawn for labeling the drinking worthiness with regards to heavy metal concentration. When all the constituent heavy metals are less than or equal to prescribed highest desirable limit, PI is assigned a value zero and NI can assume a value less than zero but not less than −1. When all the heavy metals are present below detection limit, the PI of the sample is still zero but NI will be −1. When concentrations of all heavy metals are above the highest desirable limit, its NI will be zero and PI will have some positive value. Heavy metal pollution indices of 100 groundwater samples in the Subarnarekha River Basin (SRB) collected during the pre and post-monsoon seasons have been computed using the proposed new indexing system. The drinking worthiness of all these samples has been discussed in the light of newly proposed indexing system. GIS interpolation maps of new indices, drawn for the pre- and post-monsoon SRB ground waters, clearly reflect the spatio-temporal water quality change pattern. The new indexing system is robust, flexible and may be computed using any water quality standard. It takes care of many of the apparent deficiencies of the existing indexing systems
Coalbed Methane produced water characteristics and insights from the Jharia coal field in india
No full textCoalbed methane (CBM) has emerged as one of India’s important unconventional natural gas sources in the past decade. A number of environmental questions flank the commercial development of CBM and its holistic success, one of which is coproduced water management. Present work aims at assessing the geochemistry of co-produced water samples collected from CBM wells in Jharia coalfield, India. It is found that pH is within accepted limits and the bacterial contamination is minimal. The major ions present in the water samples are sodium and bicarbonate. It is observed that the produced water is generally influenced by a mix of evaporite dissolution and silicate weathering and the samples are oversaturated with respect to calcite and dolomite. Subsequently, an assessment of the energy requirements of membrane-based technologies (such as reverse osmosis and nanofiltration) has been performed. The estimated energy consumption is 0.45–1.40 kWh per cubic meter of water, for differing levels of sodium desired in treated water. Membrane-based methods seem to be effective for treatment of CBM co-produced water, and the selection of membranes can be based on the geochemistry and also the level of treatment desired
Wireless real-time sensing platform using vibrating wire-based geotechnical sensor for underground coal mines
No full textContinuous, real-time and remote measurement of stress in underground coal mines plays a vital role in the safety of the mines. Vibrating wire-based geotechnical sensors are widely used for stress measurement of strata in underground coal mines. These types of sensors have several advantages over other geotechnical sensors. However, the measurements from these sensors are taken in-situ using conventional readout unit manually till date even in the case of deep underground coal mines where the depth of cover is more than 300 m. When sensor site moves to inaccessible places due to dynamic nature of mining, then the measurement is discontinued and instruments become abandoned. Also, sensors connected through wire get disconnected during movement of machinery, roof falls, and other associated hazards. Therefore, there is a need for wireless sensing platform for vibrating wire-based geotechnical sensors which can assess the stress on a real-time basis and obviate the impending mishap associated with the strata failure. Hence, in the present paper, authors have designed a prototype wireless real-time sensing platform for vibrating wire-based geotechnical sensors for continuous, real-time and remote monitoring of strata behavior. The laboratory trial and the field demonstration of the same have been carried out and compared with conventional readout. The results are in agreement
Fluvial Geochemistry of Subarnarekha River basin, India
No full textThe fluvial geochemistry of the Subarnarekha River and its major tributaries has been studied on a seasonal basis in order to assess the geochemical processes that explain the water composition and estimate solute fluxes. The analytical results show the mildly acidic to alkaline nature of the Subarnarekha River water and the dominance of Ca2+Ca2+ and Na+Na+ in cationic and HCO−3HCO3− and Cl−Cl− in anionic composition. Minimum ionic concentration during the monsoon and maximum concentration in the pre-monsoon seasons reflect concentrating effects due to decrease in the river discharge and increase in the base flow contribution during the pre-monsoon and dilution effects of atmospheric precipitation in the monsoon season. The solute acquisition processes are mainly controlled by weathering of rocks, with minor contribution from marine and anthropogenic sources. Higher contribution of alkaline earth (Ca2++Mg2+)(Ca2++Mg2+)to the total cations (TZ+)(TZ+) and high (Na++K+)/Cl−(Na++K+)/Cl−, (Na++K+)/TZ+(Na++K+)/TZ+, HCO−3/(SO2−4+Cl−)HCO3−/(SO42−+Cl−) and low (Ca2++Mg2+)/(Na++K+)(Ca2++Mg2+)/(Na++K+) equivalent ratios suggest that the Subarnarekha River water is under the combined influence of carbonate and silicate weathering. The river water is undersaturated with respect to dolomite and calcite during the post-monsoon and monsoon seasons and oversaturated in the pre-monsoon season. The pH–log H4SiO4H4SiO4 stability diagram demonstrates that the water chemistry is in equilibrium with the kaolinite. The Subarnarekha River annually delivered 1.477×1061.477×106 ton of dissolved loads to the Bay of Bengal, with an estimated chemical denudation rate of 77 ton km−2 yr−177 ton km−2 yr−1. Sodium adsorption ratio, residual sodium carbonate and per cent sodium values placed the studied river water in the ‘excellent to good quality’ category and it can be safely used for irrigation
STUDIES ON CLEANING POTENTIALITES OF WASHING LOW VOLATILE COKING COALS OF JHARIA COALFIELDS
No full textThe Indian coking coal reserves are less compared to the non-coking coals and the good quality coking coals have been exhausted leaving behind poor quality feed stock for the metallurgical sector. For production of Iron & Steel through blast furnace route, coking coal is an important raw material. The good quality coking coals of the upper seams are fast depleting leaving behind the inferior quality lower seam coals which are low volatile coking in nature and available in Jharia and East Bokaro Coalfields. These coals are characterized by high raw coal ash content and poor washability characteristics. CSIR-CIMFR had carried out extensive studies on the washability characteristics of these LVC coals and based on the data generated, an attempt has been made to develop a flow sheet for washing these coals at 18% clean coal ash content
A multi-responsive thiosemicarbazone-based probe for detection and discrimination of group 12 metal ions and its application in logic gates
No full textA new simple 3-in-1 multi-response thiosemicarbazone-based chemosensor has been synthesized and characterized. The probe not only exhibited high sensitivity towards the most familiar and abundant group 12 metal ions, viz., Zn2+, Cd2+ and Hg2+, in MeCN–H2O (1 : 1, v/v) medium but also can efficiently distinguish them through significant changes in their absorption and emission spectral behavior. The selectivity response was found to follow the order Hg2+, Cd2+, Zn2+ due to the different degrees of stability of their respective complexes, which was further established by TDDFT calculations and interference studies. The binding affinities of the probe towards these metal ions were investigated by absorption, fluorescence emission, fluorescence lifetime, mass spectral and 1H NMR spectral measurements. The effects of solvent polarity on the probe molecule were also examined. Due to the observation of different binding affinities and the ensuing significant changes in absorbance at different wavelengths by a combination of different inputs, L can be judiciously applied for the construction of some basic logic gates (AND, OR, NOT, IMPLICATION and INHIBIT)