Controlled blasting in a limestone mine using electronic detonators: A case study     

Arvind K. Mishra  Y. K. Nigam  Deepanshu R. Singh 《Journal of the Geological Society of India》2017,89(1):87-90

Except for very deep-seated deposits, open cast mining method has been recognized as the safest and most productive mode for mining minerals. Ever growing demand in minerals and coal has compelled the mine operators to increase the size of mine, which has resulted in an increasing trend towards large capacity open cast projects. Explosives and blasting techniques play a significant role in efficient opencast mining operations. There have been constant technological developments towards safer, faster, economical and more efficient blasting systems. Further, globally increased competitiveness has necessitated to carryout blasts in such a way that the desired degree of fragmentation is achieved in the primary blast, with minimum undesired side effects such as ground vibration, air blast/noise, flyrock, generation of oversize boulders, formation of toe, and over break or back break. Hence, the ultimate objective of the blasting engineer is to ensure that the blasts are carried out in an eco-friendly manner. This paper presents a case study of limestone mine where a controlled blasting was conducted near a green structure of wagon tippler (at 2 m) being constructed for foundation work of belt conveyor as the mine management wants to double the existing production. This paper deals with controlled blast design and its implementation using electronic detonators with signature hole technique.  相似文献   

Prof. M.P. Singh (1957-2017)     

P. K. Singh 《Journal of the Geological Society of India》2017,89(6):729-729

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Paleomires of Eocene lignites of Bhavnagar,Saurashtra basin (Gujarat), western India: Petrographic implications     

Prakash K. Singh  Vijay K. Singh  M. P. Singh  P. K. Rajak 《Journal of the Geological Society of India》2017,90(1):9-19

The Tertiary basins of Gujarat have always been a potential target for their hydrocarbon resources. The lignite resources of the region have also been an important field of research. The present paper presents the results of the petrological study carried out on the lignites of the Saurashtra basin. For this purpose samples were collected from lower and upper lignite seams from the Surkha lignite mine of Bhavnagar, Saurashtra. These samples were subjected to detailed petrographic analysis (both maceral and microlithotype). The study reveals that these lignites are dominantly composed of huminite group macerals while liptinite and inertinite group macerals occur in subordinate amounts. These lignites have attained a thermal maturity up to 0.28-0.30 percent vitrinite reflectance (VRr) which classifies them as ‘low rank C’ coals. Moreover, Bhavnagar lower lignite seam shows relatively less gelification as compared to the upper seam which suffered relatively more biochemical degradation. These lignites are characterized by high gelification index (GI) and low tissue preservation index (TPI).With the help of petrography based facies models an attempt has been made to reconstruct the environment of the paleomire of these lignites.  相似文献   

Co-seismic gravity changes in the Koyna-Warna region: Implications of mass redistribution     

K. N. D. Prasad  N. Srinivas  A. E. Meshram  A. P. Singh  V. M. Tiwari 《Journal of the Geological Society of India》2017,90(6):704-710

Koyna-Warna Region (KWR) is one of the known sites for reservoir triggered seismicity. The continued triggered seismicity over the five decades is restricted to a region of about 600–700 sq. km, which provides a unique opportunity to monitor geophysical anomalies likely to be associated with seismicity of the region. Present study confers temporal gravity changes recorded by gPhone and GRACE satellite and interprets observed changes in conjunction with seismological, geodetic (cGPS) observations and groundwater level measurements. GRACE data suggest that seasonal vertical deformation due to hydrological loading is ～ 2 cm, which corroborates with continuous GPS observations. Seasonal hydrological loading of the region, which is in a phase of reservoir loading, might be influencing the critically stressed KWR leading to the seasonal seismicity of the region. The gPhone gravity data distinctly show co-seismic gravity signals for eight earthquakes of M_w > 2 and gravity anomalies show positive correlation on a logarithmic scale with earthquake released energy. To investigate the cause of gravity changes, an estimate is made for 14^th April 2012 earthquake for M_w 4.8 using fault dislocation model. The recorded gravity changes of 189 μGal by gPhone located at a distance of 28 km from the hypocentre is much more than the estimate of ～0.1 μGal calculated for M_w 4.8 Koyna earthquake. Therefore, it is inferred that co-seismic gravity signals for eight earthquakes are primarily caused due to redistribution of mass at shallow depth.  相似文献   

Hill slope stability analysis using two and three dimensions analysis: A comparative study     

Rajesh Singh  Ravi Kumar Umrao  T. N. Singh 《Journal of the Geological Society of India》2017,89(3):295-302

Slope instability is very common phenomenon, especially in tectonically active hills of the lesser Himalaya. The deformed, weathered and fragile rocks of the lesser Himalaya are often vulnerable under natural or anthropogenic influences. There were several cases of slope failure along highway sections in Uttarakhand Himalaya. The study was carried out along a highway section of NH-109. The factor of safety (FoS) is commonly most acceptable parameter that analyses the health of slopes. The two dimensional (2D) numerical analysis techniques are commonly used to obtain the FoS. It is observed that many times FoS obtained from 2D analysis techniques do not qualify the actual conditions and are usually lower in value as compared to ground conditions. This, in turn, increases the cost of remedial measures used for protection of slopes. This paper presents a comparative study of 2D and 3D numerical analysis based on the finite difference method (FDM) using fast Langrangian analysis of continua (FLAC) codes. The study indicates that there is no appreciable difference between FoS values obtained from 2D and 3D analysis based on the selected slope conditions. The difference ranges from 0.02 to 0.07 for analysed cases in uniform rock mass. The study also exhibits some of the important analytical observations and effects of variables on resultant FoS.  相似文献   

Landslide hazard mapping along national highway-154A in Himachal Pradesh,India using information value and frequency ratio     

Kanwarpreet Singh  Virender Kumar 《Arabian Journal of Geosciences》2017,10(24):539

For the socio-economic development of a country, the highway network plays a pivotal role. It has therefore become an imperative to have landslide hazard assessment along these roads to provide safety. The current study presents landslide hazard zonation maps, based on the information value method and frequency ratio method using GIS on 1:50,000 scale by generating the information about the landslide influencing factors. The study was carried out in the year 2017 on a part of Ravi river catchment along one of the landslide-prone Chamba to Bharmour road corridor of NH-154A in Himachal Pradesh, India. A number of landslide triggering geo-environmental factors like “slope, aspect, relative relief, soil, curvature, Land Use and Land Cover (LULC), lithology, drainage density, and lineament density” were selected for landslide hazard mapping based on landslide inventory. The landslide inventory has been developed using satellite imagery, Google earth and by doing exhaustive field surveys. A digital elevation model was used to generate slope gradient, slope aspect, curvature, and relative relief map of the study area. The other information, i.e., soil maps, geological maps, and toposheets, have been collected from various departments. The landslide hazard zonation map was categorized namely “very high hazard, high hazard, medium hazard, low hazard, and very low hazard.” The results from these two methods have been validated using area under curve (AUC) method. It has been found that hazard zonation map prepared using frequency ratio model had a prediction rate of 75.37% while map prepared using information value method had prediction rate of 78.87%. Hence, on the basis of prediction rate, the landslide hazard zonation map, obtained using information value method, was experienced to be more suitable for the study area.  相似文献   

Microtremor study for evaluating the site response characteristics in the Surat City of western India     

A. P. Singh  Abhijitsinh Parmar  Sumer Chopra 《Natural Hazards》2017,89(3):1145-1166

The Surat City, which is the second most populated city in the state of Gujarat in western India, warrants site-specific seismic hazard assessment due to its rapid urbanization and proximity to major seismogenic zones. This study reports results of microtremor investigations at 72 single stations and 4 arrays in an area of 325 km² spanning the city. The resonant frequencies, associated peak amplification values and liquefaction vulnerability indices were deduced from the horizontal to vertical spectral ratios. Ground amplification (A_HVSR) in the range of 3.0–5.0 was observed in the 2.0–4.0-Hz frequency band at most of the sites. A secondary A_HVSR between 2.0 and 3.0 is also observed in the 6.0–7.0-Hz frequency band at a few sites. Locales that are most susceptible to liquefaction are identified based on their vulnerability index (K _g) exceeding the value of 10. The shear wave velocities (V _s) ≥ 500 m/s inferred from array measurements occur at 38 m depth in the western part and ~16 m depth in the eastern part of city. The response spectra estimated from strong motion data recorded at an accelerograph site in Surat from three earthquakes of M _w ≥ 3.2 that occurred in Kachchh, Saurashtra and Narmada regions are in accordance with our inferences of characteristic site frequencies and amplification. Our results, in agreement with the damage scenario during the 2001 Bhuj earthquake, provide valuable inputs for site-specific seismic hazard evaluation of the Surat City.  相似文献   

Investigations on Influence of Bio-Geo Interface on Suction Characteristics of Fine-Grained Soil     

P. S. Meenu  S. Sowmya  R. Asha Latha  B. S. Shashank  D. N. Singh 《Geotechnical and Geological Engineering》2017,35(2):607-614

Dependence of soil suction on factors such as formation of the soil, its particle size, mineralogy, pore-size distribution characteristics, water content, fabric, stress history and presence of salts has been extensively investigated by researchers. However, the influence of the microbial presence and its activity on the soil suction has not yet received researchers’ attention. With this in view, a methodology that facilitates investigation regarding the presence of ‘soil-microbial interface’, which has been termed as ‘bio-geo interface’, has been proposed in this study. Furthermore, the influence of this ‘interface’ on suction characteristics of such soils has also been investigated and the utility of the proposed methodology in addressing such issues, successfully, has been demonstrated.  相似文献   

Differential behaviour of a Lesser Himalayan watershed in extreme rainfall regimes     

Pankaj Chauhan  Nilendu Singh  Devi Datt Chauniyal  Rajeev S Ahluwalia  Mohit Singhal 《Journal of Earth System Science》2017,126(2):22

Climatic extremes including precipitation are bound to intensify in the global warming environment. The present study intends to understand the response of the Tons sub-watershed in Lesser Himalaya, in 3 years with entirely different hydrological conditions (July 2008–June 2011) in terms of discharge, sediment flux and denudation rates. Within an uncertainty limit of ±20%, the mean interannual discharge (5.74 ± 1.44 m ³ s ^?1) (±SE), was found highly variable (CV: 151%; 0.8–38 m ³ s ^?1). In a normal rainfall year (2008–2009; ～1550 mm), the discharge was 5.12 ± 1.75 m ³ s ^?1, whereas in a drought year (2009–2010), it reduced by 30% with the reduction in ～23% rainfall (CV: 85%). In an excessive rainfall year (once-in-a-century event) (2010–2011; ～3050 mm), discharge as well as total solid load was ～200% higher. Monsoon months (July–September) accounted for more than 90% of the annual solid load transport. The ratio of dissolved to suspended solid (C/P ratio) was consistently low (<1) during monsoon months and higher (1–7) during the rest of the dry period. C/P ratio was inversely (R ²=0.49), but significantly (P <0.001) related to the rainfall. The average mechanical erosion rate in the three different rainfall years was 0.24, 0.19 and 1.03 mmyr ^?1, whereas the chemical erosion was estimated at 0.12, 0.11 and 0.46 mmyr ^?1, respectively. Thus, the average denudation rate of the Tons sub-watershed has been estimated at 0.33 mmyr ^?1 (excluding extreme rainfall year: 1.5 mmyr ^?1). Our results have implications to understand the hydrological behaviour of the Lesser Himalayan watersheds and will be valuable for the proposed and several upcoming small hydropower plants in the region in the context of regional ecology and natural resource management.  相似文献   

Elemental variations in glacier cryoconites of Indian Himalaya and Spitsbergen,Arctic     

Shiv Mohan Singh  Kumar Avinash  Parmanand Sharma  Ravindra Uttam Mulik  Ajay Kumar Upadhyay  Rasik Ravindra 《地学前缘(英文版)》2017,8(6):1339-1347

Cryoconite samples were collected from two different climatic domains i.e., the Sutri Dhaka glacier, western Himalaya India and Svalbard glaciers, the Spitsbergen, Arctic, to understand the elemental source and elemental deposition patterns. The data of geochemical analysis suggest that the Himalayan cryoconite samples accumulate higher concentrations as compared to the cryoconite samples of the Arctic glaciers. The concentration of lithophile elements (Cs, Li, Rb and U) was recorded higher in the cryoconite holes of the Himalayas, especially, in the lower to the higher parts of the glacier, whereas, lower concentrations were recorded in the Arctic samples. Chalcophile elements in the Himalayan cryoconites are enriched in As and Bi while the Arctic cryoconite samples show a higher concentration of Bi, Pb and As. The higher concentrations are responsible for influencing the ecosystem and in human health related issues. Siderophile elements (Co, Fe, Mn and Ni) show high concentrations in the Himalayan samples, whereas, the Arctic samples show minor variations and low elemental concentration in these elements, respectively. In addition, a few elements, such as Ag, Mg, and Ca show higher concentration in the Himalayan glacier samples. Ca also occurs in high concentrations in Arctic glacier samples. R-mode factor analysis of the Himalayas (Arctic) samples indicate that the elements are distributed in four (three) factors, explaining 89% (90%) of the variance in their elemental distribution. The Factor 1 suggests statistically significant positive loadings for most of the lithophile, chalcophile and siderophile elements of the “Himalayan” and the Arctic cryoconite samples. The sample-wise factor score distribution shows a considerable variation in the sampling locations along the glaciers of both the regions. Factors 2 and 3, demonstrate insignificant loading for most of the elements, except statistically significant positive loading in some of the elements of the both, Himalayan and Arctic “cryoconites”. The higher elemental concentration in the cryoconites of the Himalayan region may be an indicator of the natural processes and/or attributed to the rapid industrialization in the Asian countries.  相似文献