Hydrogeological and groundwater modeling studies to estimate the groundwater inflows into the coal Mines at different mine development stages using MODFLOW, Andhra Pradesh, India

The Singareni Collieries Company Ltd (SCCL) is exploiting coal in the Godavari valley coal fields spread over 5.33 km2 in Andhra Pradesh, India. In the area, six workable coal seams have been identified in Barakar formation by the analysis of the geologic logs of 183 bore wells. A finite difference based numerical groundwater flow model is developed with twenty conceptual layers and with a total thickness of 320 m. The flow model was calibrated under steady state conditions and predicted groundwater inflows into the mine pits at different mine development stages. The groundwater budget results revealed that the mining area would receive net groundwater inflows of 5877 m3 day−1, 12,818 m3 day−1, 12,910 m3 day−1, 20,428 m3 day−1, 22,617 m3 day−1 and 14,504 m3 day−1 at six mine development stages of +124 m (amsl), +93 m (amsl), +64 m (amsl), +41 m (amsl), +0 m (amsl) and −41 m (amsl), respectively. The results of the study can be used to plan optimal groundwater pumping and the possible locations to dewater the groundwater for safe mining at different mine development stages.