IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
Not a member yet
2618 research outputs found
Sort by
Application of logistic regression, CART and random forest techniques in prediction of blast-induced slope failure during reconstruction of railway rock-cut slopes
No full textDrilling and blasting operation is often required to excavate the infrastructure slopes for enhancing their stability or creating space for upgradation. While conducting blasting, there are many incidents of slope failure or rockfall. Thus, proper planning and careful designing of different blasting parameters are essentially required to reduce the incidents of slope failure or rockfall. In the present research, the efficacies of three machine learning (ML) techniques; Logistic Regression (LR), Classification and Regression Tree (CART) and Random Forest (RF) were examined for predicting the blast-induced slope failure (BISF) or blast-induced rockfall during reconstruction of slopes on railway route. 490 databases with thirteen variables were considered for the prediction of BISF. By applying Multicollinearity and LR technique based on minimum Akaike Information Criterion values, the six most influential input parameters were identified. With the selected input datasets, fivefold cross-validation was carried out on randomly selected five sub-groups of datasets using LR tool. Then, the best LR model having the highest prediction rate was selected and with the same training and testing datasets of the selected model, the CART and RF models were also developed. The various performance indices such as correctness, recall rate, precision, specificity, F-beta score, receiver operating characteristics (ROC) and area under the curve (AUC) were calculated to evaluate the developed models' accuracy and applicability. The developed models showed good prediction abilities, with the RF model having highest performance in terms of recall rate (90%), accuracy (96.94%) and F-beta score (0.882). The LR model has higher precision (88.9%) and AUC value (0.96) than CART and RF models. The findings of the research work demonstrate the applicability of all three models in selecting the blast design parameters to prevent BISF during blasting. The use of developed models would result in saving the commuter’s lives, avoiding traffic delays and minimising property damages in similar situations
Importance of Fracturing Hard and Massive Overlying Strata for Complete Extraction of Thick Coal Seam — Case Studies
No full textEngineering efforts need to be organized as per the rock mechanic conditions of the site for efficient underground extraction of a thick coal seam. Geo-mining conditions of Indian coalfields have favoured development of thick coal seams on Bord and Pillar (B&P) method, where single lift depillaring of total thickness (SLDTT) is vital for their final extraction. Competency of heightened pillar is an important factor for uncontrolled roof-pillar interaction during caving of the hard and massive overlying strata. An increase in extraction height by underwinning of roof coal band of the thick coal seam during retreat, developed along its floor horizon, is found to be the main reason for the strength deterioration. Conducted field studies also showed that the presence of competent overlying strata caused caving after a large overhang inside the goaf varying from 6000 m2 to 12500 m2. An attempt was made to control the roof caving by a proportional increase in width of the heightened pillars and it worked well but caused the issue of resource conservation. However, another field study with SLDTT working below laminated and weak overlying strata experienced a smooth strata control condition. This fortifies the idea of strength reduction of the competent overlying strata by fracturing for a controlled strata behaviour. This paper presents the result of the field investigations to demonstrate the role of strength reduction of overlying strata for underground extraction of total thickness of a thick coal seam in single lift
Impact of topography on attenuation of noise from a cement plant in a hilly terrain
No full textThe influence of hill topography on noise from industrial plants is scantly documented, despite the fact that the noise profiles can vary in plains and in hilly terrain. Significant noise data from a cement plant flanked by hills were collected and analyzed for its attenuation over space in the direction of the valley and across the hills. It was observed that the noise attenuation is not similar to that experienced in plains owing to interactions with the mountains. The overall effect has been modelled over different distances between the four sources of the noise and several monitoring stations. The analyzed noise data showed that the influence of the major source of noise is obvious, yet difficult to differentiate. An iterated weighted distance from the noise sources, proved to be a better estimate for distance while modelling the attenuation of the noise. A relationship between the equivalent noise levels during the day and night could also be established. The effect of relative altitude and slope could be modelled using nonlinear multivariate analysis and the response surfaces were obtained for minimum, maximum and average values of the variables. Noise shadow zones could be identified with noise contouring which reflects reduction in the noise levels on hind side of the hills. The impact of topography and possible interference could thus be defined in such hilly terrain. The information can be used to define the noise mitigation strategies for adjacent habitats and mitigation of human response. The findings of the paper can also be used by prospective plants in hilly areas
Blast-induced flyrock: risk evaluation and management
No full textBlasting is an integral unit operation of the Mine-Mill Fragmentation System and is a predominant method of rock breakage in mining and civil excavations. Blast sizes in terms of number of holes per blast range from few small diameter holes with small quantity of explosive in civil excavations to hundreds of large diameter holes with tonnes of explosives in large opencast mines. While only 20%–25% of the available explosive energy is used for fragmentation and throw, the rest of energy is manifested in unwanted effect. Optimum fragmentation and throw are inherent to blasting that are desired, while as undesired effects like ground vibration, air overpressure, fumes, and flyrock are undesired that need to be controlled. Flyrock, the subject of this chapter, is an unwanted throw of individual rock fragments that travel beyond the projected distances from the blast face and have a capability to damage structures and even cause fatalities.
There have been several attempts by researchers to define the safety of blasting with respect to flyrock. One of the methods adopted for this is Risk Analysis. Risk can be defined in terms of probabilities of flyrock occurrence and the cost of damage that can occur due to a flyrock incident. The probabilities of flyrock further present a matrix of probabilities and can be defined to a better degree of reliability. However, the cost of damage due to flyrock is a very subjective matter, particularly, in case of fatalities. Such issues can be solved by adopting different methods like rules for safety or unsafe conditions. This chapter will discuss the intricacies of flyrock risk assessment while reviewing the existing state of the art and lay foundations for future research possibilities to address flyrock in detail. A new concept of Risk Management for flyrock prevention has been introduced here
Assessment of active tectonics in the Siwalik basin around the Subansiri river, NE India.
No full textIn this paper we evaluate the morphotectonics of the area around the Subansiri river in north-eastern India. Research focuses on understanding the impacts on areas experiencing
active tectonic deformation. It also explains the variety of kinematics observed in the area from the Miocene to the present. The tectonics can explain some structures related to the extensional tectonics predominant in the region and the development of the minor and major morph
structures driven by faults with different kinematics. We developed a morphotectonic
evolutionary model for the area based on the morphotectonic analysis and geological mapping.
Morphotectonic indices used to evaluate the tectonic activeness in this study are Mountain Front
sinuosity Index, Valley Floor Width to Valley Height Ratio, Asymmetry Factor, Transverse
Topographic Symmetry Factor, Mountain Front Steepness Index, Basin Shape Index and Stream
Length Gradient Index. There are numerous lineaments present in the study area which are
trending in NW-SE and NE-SW directio
Geochemical, mineralogical and toxicological characteristics of coal fly ash and its environmental impacts
No full textCoal and coal-based products (by-products), along with other fossil fuels should be used with caution because of their impact on human health and the global climate. In the light of the environmental impact these fossil fuels cause, it's essential to understand the elemental configuration of coal-derived samples and their impact on the ecosystem. Some reports in past have described, geochemical and mineralogical physiognomies of fly-ash and their impact on the environment. However, a comprehensive investigation of various aspects of fly ash like geochemistry, mineralogy, morphology, and toxicological effects has been very sparse and the present study reports the above aspects. The ICP-OES studies confirm the presence of various elements (Al, Ca, Fe, Mg, Na, P, S, Si, and Ti) in the samples. The XRD analysis exposed the presence of minerals like Quartz, H-Hematite, Anatase, Muscovite, and Rutile, in addition to the various phases such as amorphous and crystalline in the fly-ash. Specific samples also possessed Ilmenite which is uncommon in many other samples. Chromium and lead, the well-known heavy metals to cause soil and water pollution in the neighbourhood were found to be existing in higher concentrations in the fly-ash samples, whereas cadmium was found to be the least among the toxic elements found in the samples. The samples were subjected to FE-SEM analysis, which reveals the presence of irregularly shaped minerals and unburnt carbon known to reduce the burning efficiency of coal, especially in power plants. Toxicology studies reported in the work suggested that fly-ash is toxic to the environment at higher concentrations than at lower concentrations
Vapour Phase Synthesis of 2-Methylpyridine and 4-Methylpyridine Over Potassium Salts of 12-Tungstophosphoric Acid
No full textVapor phase dehydrocyclization reaction of acetaldehyde and ammonia was investigated over K salts of
12-tungstophosphoric acid as catalysts in a continuous flow fixed bed reactor at 350–450℃. The yield of 2-methylpyridine
and 4-methylpyridine were found to be in the range of 38.0–64.5%. The 2-methylpyridine and 4-methylpyridine are used for
the preparation of insecticides, poultry drugs, cattle drugs and anti-tuberculosis drugs, veterinary analgesics etc.
respectively. The reaction conditions such as temperature, contact time, and molar ratio for achieving optimal yield with
respect to 2-methylpyridine and 4-methylpyridine were discussed. Catalysts were characterized through BET surface area, FT-IR,XRD and TGA. NH3-TPD studies exhibit the moderate acidity. The morphology of the catalysts was also studied by FESEM
Geochemical characteristics, origin and forms of sulphur distribution in the Talcher coaleld, India
No full textGeochemical studies conducted on samples from the Talcher coal eld can help elucidate the occurrence, origin and different forms of Sulphur in the area. In this coaleld, sulphur is present as organic sulphur, pyritic sulphur, and sulphate sulphur. The total sulphur concentration ranges from 0.5% to 1.13%, which falls under category of low-sulphur coals. Organic sulphur accounts for 70%, and pyritic sulphur accounts for 25% of the total sulphur in the Talcher coal. The presence of a minor proportion of sulphate sulphur (approximately ≤ 5%) indicates that Talcher coals are formed under non-marine environmental conditions. Results from proximate analysis expose the gross composition of coal. The air dried results indicate that, the moisture content varies from 2.6 to 4.8%, ash content ranges from 29.7 to 45.6%, volatile matter ranges from 24.54 to 29.65%, and xed carbon content varies from 25.96 to 37.25%. It is observed that when the ash percentage of coal samples is less than 40%, the gross caloric value of the Talcher coaleld ranges from 4000 to 5000 kcal/kg, and when the ash percentage of the coal samples is greater than 40%, the gross caloric value is less than 3000 kcal/kg. The elemental com-positions of the Talcher coaleld were also determined based on the dry mineral matter free basis. Carbon, hydrogen, nitrogen, sulphur, and oxygen content were determined. Macerals and mineral matter were studied using a coal Petrological microscope. It was observed that macerals account for 69% of the total mass of coal while pyrite represent 1.8% and other minerals 29.28%. Results obtained using the eld emission scanning electron microscope technique show that the major sulphide minerals present in the Talcher coals are pyrite (FeS2) and marcasite (FeS2), with pyrite being the more common. Sphalerite (ZnS) was found in some samples. The study has revealed the geochemical characteristics, origin and forms of sulphur distribution in the Talcher coaleld
Improving Workplace Environment of a Deep Underground Coal Mine with Multiseam Workings: An Alternative Approach
No full textThe increasing demand for coal and depletion of shallow depth reserves are pushing towards deeper mining. In deeper coal mines with multi seam workings, the problem of ventilation surges many folds primarily related to air quantity requirement, heat, humidity and spontaneous heating/fre in goaved (gobbed) out areas. The paper describes the design of a new approach to improve the ventilation system of a real-life deep underground coal mine with multiseam workings. For this, the ventilation problem of one deep underground coal mine 6&7 pits Bhutgoria Amalgamated Colliery of Tata Steel Ltd. with multiseam workings has been studied in detail to determine an appropriate solution. A ventilation survey of the mine and computer simulation of the ventilation network has been carried out to reach a practical solution. Ventilation survey results have been analyzed to develop a representative ventilation network of the mine for both qualitative and quantitative analysis. Further, computer simulation of the ventilation network of the mine has been performed to virtually verify the application of a high capacity booster fan in the present ventilation circuit without disturbing the vulnerable areas. Field validation is also carried out after the implementation of the solution in the mine to determine its efcacy. Thus, the findings of this paper can be directly applied for the installation of booster fans to achieve the required air quantity in deep underground coal mines with multiseam workings having spontaneous combustion liabilities of upper seam goaved out areas
Impact of siderite on Rock-Eval S3 and oxygen index
No full textOver the past four decades Rock-Eval pyrolysis has become a common means to type organic matter. The
modified van Krevelen diagram, using the hydrogen and oxygen indices, has become a commonly used tool for
organic matter classification. It assumes that the components used to calculate the two indices are representative
of the indigenous organic matter, which is especially the case for the oxygen index. This study provides a series of
experimental results that further characterize the impact of siderite on the hydrogen and oxygen index values,
which decrease and increase, respectively, with increasing mineral content. This work suggests that the changes
in hydrogen index values are a result of the interaction between the mineral phase and the generated hydro�carbons, where hydrocarbons may be adsorbed on to the mineral surfaces and not fully released. The increase in
the oxygen index appears to be a result of mineral decomposition and the release of CO2. The oxygen index was
found to be particularly sensitive to the presence of siderite in the sample. Siderite decomposition was found to
occur at temperatures below often published decomposition temperatures and at or below the S3 peak trapping
temperature (390 ◦C). Thus, the impact of organic carbon content and mineral interaction need to be taken into
consideration when characterizing organic matter, especially when siderite and to a lesser extent other carbonate
minerals are present. At lower organic carbon levels, organic matter will appear more gas-prone and would
suggest that the organic matter has been strongly oxidized. Although corrections have been proposed in the
literature they reduce the value of the Rock-Eval “quick” screen by adding additional analyses or data treatment.
It is further suggested that the effect may be sensitive to the early diagenetic environment as well as cation
substitution