ASSESSMENT OF MINING ACTIVITIES IN JHARIA COALFIELD USING REMOTE SEING

Abstract

Mining in India is a major industrial activity which contributes significantly to the national economy. The overall contribution of mining/mineral sector in terms of GDP is about 2.2 to 2.5% (Annual Report, 2010-11), Ministry of Mines, Government of India). According to the Indian Ministry of Mines, 80% of mining is for coal and the remaining 20% for various metals and other raw materials such as gold, copper, iron, lead, bauxite, zinc and uranium. As a prospering economy, India faces energy security as a growing challenge and the coal production is expected to grow at a compound annual growth rate (CAGR) of around 7% during 2011-12 to 2013-14. The Indian coal market is set to witness great boost in near future because of the rising government initiatives. Mining also has a significant impact on the environment, but the environmental awareness of the global mining industry has become an important issue only in recent years (Lamb, 2000). The three major activities of the mineral resources mining industry are mining, mineral processing, and metallurgical extraction. These produce wastes, thereby causing serious environmental harms (Lottermoser, 2007). Overall environmental impact due to mining depends on number of factors, in particular: the method of mining (opencast/underground) and their magnitude (Bell et al., 2000). The remote sensing and GIS techniques are extensively used since last few decades specially for mineral exploration. However, these techniques are, at present, also being used for management and monitoring of mining operations mostly by the developed economies (Lamb, 2000). During ‘surface mining’ activities - extraction of ore along with stripping and dumping of overburden, the land cover and land use of the mine area is continuously changed. Sustainable mining requires constant monitoring of these changes to identify the long-term impacts of mining on environment and land cover to provide essential remedial measures. Remote sensing techniques /earth observation using space based sensors are very powerful tools for obtaining rigorous data over a period of time and hence minimizing the need of time-consuming and costly field measurements. Effect of mining on surface features and soil cover is to some extent detectable with satellite earth observation data. Opencast mining (OCM) can directly affect the ground surface resulting formation of depression and also heaps created by dumping of waste. The other serious and direct effect is removal of top soil, damage of manmade structures due to blasting, etc. adversely effecting human settlements. In addition, there can be many more such minor influences on the area affected by mining. These direct variables are predictable and caused by the mining operations itself and restricted to the same place and time. In addition, there are many more indirect effects which crop up at a later stage and also can propagate to a larger distance and for example perturbation of surface and ground-water hydrology. Indirect variables may include cumulative effects related to induced changes in the pattern of land use and related effects on soil, air and water and other natural systems. Quantifying the temporal and spatial patterns of land use/land cover (LULC) change, as well as its consequences for ecological, hydro-climatological, and socioeconomic systems on the earth, is a central focus of land change science (Turner et al., 2003), thus underlining a need for more careful, objective, and quantitative estimation of the trajectory and spatial dimension of mined land conversions. Knowledge of the extent of mining and reclamation is critical to managing or mitigating the potential impacts of surface mining. Remote sensing has been used widely to characterize land cover changes and maps derived from remotely sensed data provide critical inputs for understanding dynamic process.