Hydraulic connection of aquifers in Barapukuria Coal Mine, Bangladesh

In order to further identify the hydrogeological characteristics and hydraulic connection between aquifers of Barapukuria Coal Mine in Bangladesh, and provide a theoretical basis for the prevention and control of mine water disasters, this paper analyzes the hydraulic connection between Neogene UDT aquifer, Ⅵ coal roof aquifer and Ⅵ coal aquifer based on 19 sets of water quality test data, combined with the spatial distribution characteristics of aquifers, field structure characteristics, water level duration curve, hydrochemical type and hydrogen and oxygen isotope characteristics. The results show that the LDT aquifer in the northern part of the well field is partially missing, which provides conditions for the water supply of the UDT aquifer to the coal measure strata. The roof aquifer of coal seam in the north wing of the mine field is closely related to the water level change law of UDT aquifer, and the water level elevation is similar, which preliminarily proves that there is a hydraulic connection between the two. The water of each aquifer is HCO₃-Ca·Na·Mg type, which is low salinity water, further proving that there is a hydraulic cycle between each aquifer. Cluster analysis results show that water quality of each aquifer has a certain degree of correlation, and the degree of hydraulic connection between aquifers is deduced. Hydrogen(δD)oxygen(δ¹⁸O) isotopic characteristics are distributed near the global atmospheric precipitation line, indicating that atmospheric precipitation is the common recharge source of aquifers. The research results can guide the prevention and control of water disaster in Ⅵ coal seam mining of Balapukuliya Coal Mine in Bangladesh.