Singh A.K.,Indian Central Institute of Mining and Fuel Research
Environmental Earth Sciences | Year: 2011
Road dust collected from India's richest and oldest coal mining belt of Dhanbad and Bokaro regions was analysed for particle size characteristics and elemental composition. The particle size distribution pattern shows dominance of 500-250 μm and 250-125 μm size fractions, constituting 45-58% of the mass size spectrum. Si is the most dominant element and its concentration varied between 29.3 and 36.4% with the average value 34.3%. Fe, Ti and Mn are the dominant heavy metals followed by Zn, Cr, Pb, Cu, Ni and Co. No significant differences concentration of metals between sampling sites was apparent; however, some sites tend to accommodate relatively higher metals due to its proximity to industrial and mining sites. In general, finer fraction (<63 μm) tend to contain 1-3 times higher metals as compared with the bulk composition. Except Pb and Mn all the measured metals are generally lie below grade zero, suggesting that there is no pollution threat with respect to these metals in roadway dust from the studied sites. Geochemical speciation study shows that the lithogenic phase is the major sink for heavy metals. Fe-Mn oxide and organic are the major non-lithogenic phases and Pb and Zn are the major elements of the non-lithogenic phase. © 2010 Springer-Verlag.
Bagde M.N.,Indian Central Institute of Mining and Fuel Research
International Journal of Rock Mechanics and Mining Sciences | Year: 2016
The Ajanta caves are classified as a UNESCO World-heritage monument, where ancient Buddhist rock-cut caves from the Second Century BC to 6th Century AD are found. The caves were carved manually in Basaltic rock mass in the Deccan trap basaltic flow of the Ajanta Formation of the Sahyadri Group in the Upper Cretaceous age. In the Ajanta caves, the hillside slopes are predominantly covered by surface boulders. Boulder dislocations caused by long-term rock mass deterioration, distressing, water percolation and weathering for a strike length of 600. m, and a height of 75. m; are a major concern when considering the safety of both visitors and site personnel, as well as with regard to the preservation of the historic UNESCO World Heritage site. This study was carried out to assess and characterize the formation of boulders with possible stabilization measures to be planned of a boulder field and slope surface is described and discussed herewith. The possible geological mode of development of the boulder field, rock mass characterization of slope, boulder stabilization philosophy is presented herewith along with planned various stabilization measures considering the esthetic value of the World Heritage site at Ajanta. © 2015 Elsevier Ltd.
Jhanwar J.C.,Indian Central Institute of Mining and Fuel Research
Rock Mechanics and Rock Engineering | Year: 2012
A classification system for the slope stability assessment of opencast coal mines in Central India was conceived and developed based on a research work and experience on slope stability of six opencast coal mines in Wardha Valley Coalfield (WVC). The developed system, named Opencast Slope Stability Assessment System for Coal Mines (OPCASSTA-COAL) was applied to assess the rock mass condition (RMC), the slope condition and the slope failure hazard in two coal mines of WVC and was found to be of practical application. It was found that the sandstone rock mass is moderately to highly weathered and is very weak to weak. The rise side slope is apparently stable, moderately jointed with no visible instabilities. The RMC of NKOC and DOC mines were assessed and it was found that RMC rated as extremely poor in the upper region of dip side and very poor to poor in the lower region of dip side and rise side of NKOC mine. Field studies indicate that the intact rock strength (IRS) and the total number of joints/fractures intersecting a unit volume of rock mass are important parameters.
Singh R.V.K.,Indian Central Institute of Mining and Fuel Research
Procedia Engineering | Year: 2013
Spontaneous heating and fire in coal mines is a major problem worldwide and has been a great concern both for the industry and researchers in this field. Majority of fires existing today in different coalfields are mainly due to spontaneous combustion of coal. The auto oxidation of coal ultimately leads to spontaneous combustion which is the major root cause for the disastrous of coal mine in leading and coal producing countries like USA, China, Australia, India and Germany. It is a slow process and the heat evolved is carried away by air. This process of self-heating of coal or other carbonaceous material resulting eventually in its ignition is termed as "spontaneous heating" or "auto oxidation". Coal can interact with oxygen in the air at ambient temperature liberating heat. If the heat is allowed to accumulate the interaction rate increases and may ultimately lead to fires - known as spontaneous fires. The exact mechanism of the reaction of oxygen with coal is not completely understood as the chemical nature of coal is not yet fully established. But most of the workers agree that the reaction of oxygen with coal is a surface phenomenon and proceeds through a loosely bound coal-oxygen-water complex with subsequent steps being breakdown of the complex to simpler molecules such as CO, CO2 and H2O etc. Most popular hypothesis is that the overall reaction proceeds through a chain mechanism with moisture facilitating the formation of free radicals that act as chain carrier. Due to fire in coal mines, hues quantity of noxious gases liberated in the atmosphere which damage the ecological balance of nature. There are various technologies available in different parts of world to prevent and control spontaneous heating. Out of these technologies, chemical inhibitors play a vital role to control and combat fires. The main objective of this paper is to elaborate the causes, mechanism of spontaneous heating and technological advancement mainly development of chemical inhibitors for controlling and combating fire in coal mines. © 2013 International Association for Fire Safety Science.
Bandopadhyay A.K.,Indian Central Institute of Mining and Fuel Research
International Journal of Coal Geology | Year: 2010
A suite of thirteen Indian thermal coals have been subjected to FTIR examination to determine their quartz content. The coal samples were ashed at 815 ± 10 °C using standard procedures and the high temperature ash (HTA) of each coal was used to make a tablet with KBr under pressure. Each tablet was then subjected to FTIR scanning to obtain a spectrum at a resolution of 2 cm- 1. The 800 cm- 1 quartz doublet observed in each spectrum was used to obtain quantitative information on the percentage of quartz present. The data were compared with interpretations from ash analysis. The result showed a good correlation between the two sets of data (R2 = 0.84), suggesting the potential of the method for routine testing of quartz content of coal in laboratory, especially as it takes less time than other methods. © 2009 Elsevier B.V. All rights reserved.