Nergis et al. /Int.J.Econ.Environ.Geol.Vol. 9(4) 68-73, 2018 68 Management of Ground Water Hazard: A Case Study from Thar Coal Mines, Pakistan Yasmin Nergis 1 , Muhammad Jahangir Khan 1 , Naeem A. Mughal 1 , Mughal Shareef 2 , Jawad Abdullah Butt 2 1 Department of Earth and Environmental Sciences, Bahria University, Karachi Campus, Pakistan 2 Environmental Research Center, Bahria University, Karachi Campus, Pakistan *Email: nergisyasmin.bukc@bahria.edu.pk Received: 30 May, 2018 Accepted: 24 December, 2018 Abstract: This study covers the Thar coal field block-II located in the southeast of Sindh, Pakistan. The aim of present study is to identify the impacts of ongoing coal mining activity on ground water quality and water table in community wells of villages in Thar coal mine block-II. The ground water samples from 58 community wells (located in 21 villages of block-II) were collected and analyzed for the water quality parameters like water table (depth), electrical conductivity/TDS, and pH. The groundwater samples from community wells and Gorano pond were analysed to assess water quality. The reserved area of Gorano pond is about 1500 acres, wherein water discharged from aquiufers in coal mining area of block-II is being accumulated. The extracted ground water is being disposed off in multiple depressions near villages Gorano, Kathar and Dhukar Shah Keywords: Ground water hazard, Thar coal, TDS, dewatering, Pakistan. Introduction The discovery of Thar coal deposit is estimated to be over 175 billion tons, which has uplifted Pakistan's coal resources to more than 184 billion tones giving it the eleventh position in the list of 12 major coal producing countries of the world (Abbas and Atique, 2005; GSP report, 2002). The district Tharparkar lies in south- eastern arid zone of Sindh (Pakistan) which comprises two sub-divisions; Mithi and Chachro and four sub- districts (Talukas) of Mithi, Nagarparkar, Diplo, and Chachro. Thar coalfield encompasses about 9,600 sq. km (140 kilometers (N-S) and 65 kilometers (E-W)), of Sindh desert. Spatially distributed Thar coalfield is divided into twelve blocks (Fig. 1). The type of coal found in the Thar coal fields is invariably lignite, which is a low-grade pyritic coal that is generally used in modified industrial furnaces to generate heat for boilers, coke oven heaters, brick kilns, etc. The average quality parameters of the lignitic coal are: avg. 7% ash, 1.4 % sulphur, 48% moisture (in-situ) at heating value 5140 Btu/lb. In current scenario only Thar coal block-II was allocated for open pit mining. Therefore, block-II was selected for research study. The study area has the characteristics of a desert and has no regular or permanent surface water bodies. In the absence of proper water resources, sometimes the water can be found in small level trails or depressions, which host the rain water. Primarily, the ground water is recharged by rainfall. The rainwater precipitates through top cover of sand dunes and desert’s topography to recharge the ground water resources of Thar. There are multiple aquifers present above the coal zone, called coal roof aquifer. These aquifers are forming two to three levels consisting of compact sand horizons with thickness in few meters, (Fig. 2). Several artificially dug depressions are usuall built of silty clay and caliche material (Zaigham et al., 2009). This study aimed at identification of ground water hazards and impacts of ongoing coal mining activity on ground water quality and water table in mining areas (Fig. 3). The dewatering of groundwater likely to pose moderate to major hazards at and during the pre-mining, mining and post-mining stages. The presence of aquifers at the coal roof level and basal level may produce major hazards during/after the mining operation (Nergis et al., 2018). Geology the Study Area The sedimentary column succession diminishes from west to east and has a thickness of around 250 m in the Thar coal field (GSP report, 2002). The core samples demonstrated that coal-bearing strata of Paleocene- Eocene dregs un-conformably overlie the Precambrian rocks of volcanic composition (Zaigham et al., 2009). The generalized stratigraphic sequence of Thar coalfield area is given in Table 1. It comprises Basement complex, coal-bearing Bara Formation, alluvial deposits and sand dunes (Zaigham et al., 1996 a, b). The coal beds have variable thickness from 0.20 to 36 m (GSP report, 2002). The coal is dark or grayish dark in color. The overburden comprises three types of materials: hill sand, alluvium and sedimentary succession. The aggregate overburden is around 150 to 230 meters (IBRD, 2001). Materials and Methods The study is based on ground water samples collection and temporal analysis to carry out qualitative and quantitative assessment of ground water quality in boreholes of nearby villages in block-II and Gorano pond discharge area. Water samples were collected from community wells located in villages of block-II, and Copyright © SEGMITE Open Access ISSN: 2223-957X Int. J. Econ. Environ. Geol. Vol. 9 (4)68-73, 2018 Journal home page: www.econ-environ-geol.org