HYDROCHEMICAL STUDY IN THE PENCH VALLEY COAL MINE AREA, MADHYA PRADESH

Abstract

The area under study is a part of Pench Valley Coalfields and lies in Chhindwara district of Madhya Pradesh, India. The geographic co-ordinates of the region are 22°10'-15' latitudes and 78°40'-50' longitudes, a small region which can be classed as rural. The river Pench flows west to east in this sector which is joined in by three tributaries from the north. Typical deccan trap morphology dominates, giving an overall rugged appearance to the area. The presence of coal has promoted mining industry for over a century and a highly developed mining infrastructure is working in the region. The topmost workable coal seam is nearing exhaustion but the II and III horizons are under production. The geochemistry of Pench area has undergone a great change as a result of regular coal mining. The groundwater which is accumulated in the mines is constantly pumped out in order to facilitate working. This water in most cases is directly poured into the river Pench through crudely constructed drains or naturally available streams. The continual large scale pumping onto the surface, in general, results in drop of water table and even complete drying of wells in summer; thereby depriving the local inhabitants to resort to easily available, effluent, minewater drains for fulfilling their basic needs. Such a practice of directly utilizing the untreated minewater for irrigation and occasionally even for drinking purposes (when there remains no other source of water available nearby) has gained popularity under binding human needs for bare necessities. This has become quite common in the past few years, and has led us to study mine related effects on the natural environment and the response of natural environment to adjust to the changed physico-chemical conditions. Moreover, the size ABSTRACT of the area being in few tens of square kilometers demands a pin pointed study to depict the behaviour of major and trace elements in the recent geological setup. The main concern of the present study was to monitor and evaluate the impact of mining over the environmental health and ensuing geochemical degradation of the surroundings. The study was taken up with the objectives to look for the behaviour of major and trace elements responsible for human health, with special attention towards effects of mining on soils, waters and on the inhabitants. After a thorough reconnaissance survey, the sampling sites were selected to be monitored for pre- and post-monsoon periods for the Groundwater, Surfacewater and Minewater. Samples of all the waters were drawn for two consecutive years (1991 & 1992) for assessing the trace elements and other water quality parameters. The soils were surveyed and representative samples were picked up to undergo cold extraction (leaching). The leachate was then analyzed to imbibe the soil chemical responses to the variety of waters pervading the region. The laboratory results are thus compared to the natural soils. Spatial variation of different parameters has also been attempted to, by virtue of Isocon maps, so that the variations within the region are focused in and pointed out which are generally overlooked. Finally, an assessment is made to evaluate the area based on water and soil responses for the behaviour of trace elements and other water quality parameters. Hence, the study presents a fundamental picture of the ongoing geochemical variations and interprets their future trends so that adequate grasp is made in time.