Assessing the environmental impacts of coal mining using analytical hierarchy process: A case study of Jharia coal-field, India

Jharia coal-field holds unequivocal importance in the Indian context as it is the only source of prime coking coal in the country. Haphazard mining over nearly a century has led to environmental changes to a large extent such as degradation in the quality of air, water, soil, changes in landform, land-use/land-cover and vegetation distribution. Environmental impact assessment is a process to assess the changes occurring in the environment due to a particular activity, such as mining in this case. It has been carried out by analyzing various geo-environmental factors such as air, water/drainage, soil and vegetation. In this study, opinions of experts from different fields have been utilized to determine the impact of various coal mining activities on the local environment of Jharia. After that impact assessment has been carried out using a multi-criteria decision making technique, namely analytical hierarchy process (AHP). AHP has been chosen for impact assessment as it is an effective tool for combining qualitative and quantitative factors and has an ability to check the inconsistencies in judgements. The process involved the generation of pairwise matrix, the calculation of factor weights and estimation of consistency ratios. Consistency ratios for different criteria have been found to be within acceptable limits (< 0.10). The results suggest that coal dust is the major factor affecting air and soil; vegetation is most severely affected by opencast mining and fires; and water is affected by acidic waters and leaching from washeries. Key-Words: Environmental Impact Assessment; Multiple criteria evaluation; AHP; Coal mining; Air, water, soil pollution; Jharia