Monitoring and modelling the deformation state of a dyke of a flotation tailings reservoir of a copper ore mine

Abstract

The mining areas of the copper ore mines in Poland contain tailings storage facilities. Because of operational safety issues and to minimize the exposure of local neighbourhoods to the risk of such reservoirs failing, mining operations are limited during the period of waste storage, thereby reducing the impact of exploitation on these objects. Nevertheless, continuous monitoring and analysis of the deformation state of reservoirs and associated facilities are required. Monitoring is most often carried out using geodetic methods, while the deformation analysis is based on determining the displacements of control points and making short- and long-term forecasts of changes in land surface deformation. Presented here is an analysis of changes in the state of displacements and dyke deformations of a currently closed copper flotation tailings reservoir that was used in the 1970s. After the storage of waste was stopped, an intensive two-stage mining operation was carried out under the reservoir. The results obtained from the geodetic monitoring of displacements and deformations of the reservoir dyke are compared with the model values, and the usefulness of the applied theoretical model for describing the vertical and horizontal displacements and horizontal deformations is verified. Based on the comparison results, a hypothesis is presented regarding the causes of the actual condition of the movements of the reservoir dam crest against the background of the expected movements obtained from theoretical modelling. The presented conclusions revise a very rigorous approach to protecting flotation tailings reservoirs against the effects of underground mining.