FEM for prediction of surface deformations induced by flooding of steeply inclined mining seams

The closure of coal mines is closely linked to the change in European energy policy regarding the reduction of CO2 emissions. The process of closing underground mines has impacted many mining companies, especially in Europe. Along with the decision to close a mine, a number of steps have to be taken with regard to its liquidation. One of these is the decision to begin flooding the mining excavations with underground water. The process of liquidation of an underground mine brings with it a number of problems and dangers related to, among others, the environment, geomechanics and surface protection. This article aims to present the possibility of forecasting deformation of the land surface as a result of the flooding of underground excavations characterised by steeply inclined seams and to indicate the dangers posed by the liquidation of underground mines to the environment and civil engineering structures. The use of numerical modelling is an innovative approach to the problem of steeply inclined flooded seam induced surface deformations. It is an interdisciplinary area that encompasses mining and environmental protection. The authors present numerical calculations and simulations of land surface uplift resulting from the liquidation process for a case study (Spanish mine). The calculations were made by Finite Element Modelling (FEM). The authors have created numerical models characterised by steeply inclined seams, and based on the authorship methodology they have calculated the surface deformation. The obtained results were verified by measurements. Such analysis was never done before. The authors proved that with numerical modelling and developed methodology, it is possible to successfully forecast surface deformations during the liquidation of mines by flooding. Then, based on the obtained forecast values, a discussion on the possibility of mining damage in the analysed area may begin. Such damages have been observed during the flooding of German mines. The conducted research is interdisciplinary in the field of mining and civil and environmental engineering. Furthermore, the very issue of damage is also important from the socio-economical point of view. (C) 2021 Elsevier Ltd. All rights reserved.