Prediction of hydrodynamic conditions in the influence zone of Stoilensky Mining and Beneficiation Plant

Abstract

Sources of anthropogenic impact on hydrodynamic conditions in quarrying an area have been identified as the drainage system, tailings dump and groundwater intakes. It has been determined that the induced factors associated with the operation of Stoilensky Mining and Beneficiation Plant have formed the modern hydrogeological conditions of the area. The analysis of the hydrogeological conditions in the region was carried out. It was found that the drainage of the quarry led to a change of the conditions of groundwater recharge and discharge, to an increase in the filtration rate and in the aeration zone thickness. That contributed to the activation of rock leaching, flow of process water into aquifers, and to a change of water flow between aquifers. The groundwater levels of the Upper Jurassic measures decreased in pitwall rock mass. The groundwater ridge formed at the site of the tailings dump. The transformation of balance elements of groundwater formation took place in the area: the main source of recharge for the Upper Jurassic rocks is the tailings dump. The numerical model of groundwater seepage is described. The aquifer is modeled as a four-layered thickness. Simulation was carried out using MODFLOW program of GMS system. The predictive calculations took into account the expansion of pitwall, the reconstruction of the underground drainage system, the building-up of the tailings dump with thin pulp up to the project levels. It has been established that the Oskolets river is a source of the aquifer recharge as a result of operation of the drainage system of the quarry. At the same time, the Oskol river drains groundwater. It was revealed that the main inflow to the quarry formed due to groundwater from the Upper Jurassic rock mass and, in a smaller degree, from the Archaean–Proterozoic aquifer and due to atmospheric precipitation. The volumes of seepage of industrial water from the tailings dump have been determined.