Specific features of mining out the penthouse between the open pit floor and the underground mining zone at the International mine

The stress-strain state of the rock mass at the International mine has been assessed for mining the reserves of its upper levels. Options of the mining system that is most suitable for these conditions have been considered, i.e. a slicing method with consolidating stowing of the mined-out space and the room-and-pillar order of mining within a layer and the ascending order of layer excavation, as well as a system with induced sublevel caving of the ore and the host rocks. Mathematical modeling of changes in the stress-and-strain state of the rock mass have been performed for the selected mining method at different mining stages. It is shown that the stresses arising in the ore mass within the zone of mining operations will not lead to loss of strength and destruction of the structural elements of the mining system, and therefore, the proposed mining options will allow to excavate the reserves of the penthouse with a minimal loss of valuable raw materials while ensuring safe conditions of mining operations at the International mine.