Quantifying environmental impact of unplanned mining through integrated non-invasive geophysical methods: a case study from Jharia coalfield, India

Abstract

The Jharia coalfield stands as a paramount asset within the Indian economy. However, many pressing issues, such as coal fires, land subsidence, unplanned mining, child labor, deforestation, and air pollution, demand immediate attention. Effective planning and comprehensive mitigation strategies are imperative to address these challenges. This research centers on evaluating an area near Bhuiyadih village subjected to rat hole mining using non-invasive geophysical methods. The evaluation includes a joint analysis of multiple geophysical techniques, such as gravity, magnetic, and seismic surface wave methods. The potential data has been evaluated by generating edge detection, upward continuation maps, and radial average power spectrum (RAPS) plots. Seismic surface wave velocity structure has been evaluated and used as a constraint to model the subsurface structures using potential field data. Evaluating subsurface layers from the RAPS, Seismic surface wave model, and 2D model generated from the potential data indicates a weathered layer, an overburden sandstone layer, and a coal seam of thickness ~ 4.5�m, ~ 14�m, and ~ 11�m, respectively. The wideness of the gallery boundary has been evaluated using the composite lineament map and found to be surpassing approved limits for underground mining, signifying evidence of rat hole mining practices. The thin pillars in the coal seam and fractures observed on the surface indicate the failure of overburdened rock masses, leading to land subsidence in the nearby villages. The study reinforces the urgency of shifting the local population to a safer environment to avoid unfortunate situations. � The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.