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Assessment of the impact of surface mining on hydrogeology of Raniganj coalfield area
Published in -
Volume: 31
Issue: 43469
Pages: 1 - 21
The study area (c.156 sq.km.) includes eight active and several abandoned open cast mines and lies in the western part of the Raniganj Coalfield in Barddhaman district of West Bengal. Geologically the areas includes Talchir, Barakar and Barren Measures Formations of Lower Gondwanas above the Precambrian metamorphics. Groundwater occurs in the near surface zone of weathered Gondwana sedimentaries in an unconfined condition. The seasonal average depths to water table in the mining area are 7.1m, 3.1m, and 5.3m while those of non mining area are 5.5m, 2.7m and 4.3m in the pre-monsoon, monsoon and the post-monsoon periods respectively. Two intermediate groundwater flow systems in the ESE and SW directions have been recognized which are controlled by Nonia Jhor and Barakar River respectively. Besides, a number of local flow systems have developed due to coal mining activities.Detailed geochemical analysis of groundwater reveals four hydrochemical facies viz. Faciesl :Ca-Mg-HC0 3 facies, Facies2:Ca-Mg-HC03 -CI facies, Facies3:Ca-Mg-CI- HC03 facies, Facies4:Ca-Mg-CI facies. The general quality of ground water deteriorates gradually from Faciesl to Facies4.Aerially they occur in a sequence of Facies4 - Facies3 - Facies2 - Faciesl from active mines outwards. S04concentrations are found to be high in this region with higher values neare to the mines. Groundwater is also found to be contaminated with heavy metals, particularly with iron and manganese, by the mining activities.
About the journal
JournalIndian Journal of Earth Sciences