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The article presents some results of studies of the effect of the design of charges on the yield of fine fractions during blasting operations in open pits during mining. The data obtained serve to formulate recommendations for conducting experimental research in an industrial environment. These data are also useful for determining the influence of the design features of the charge, such as the size of the air gap and the decompaction of the explosive on the intensity of fragmentation and the nature of the stress localization in the rock destroyed by the explosion energy during the extraction of valuable crystalline raw materials and flux limestones. The relevance of research is due to the need to expand the capabilities of controlling the action of the explosion to obtain rational fragmentation of the rock mass, as well as the economic feasibility of reducing the loss of minerals, and eliminating the negative factors of blasting. A research methodology has been developed and tested using composite simulation models for blast-hole charges and within the blasted block. In this work, the Smoothed Particle Hydrodynamics method (SPH) is used for computer simulation. As the practice of calculating dynamic problems of geomechanics has shown, this method is a convenient tool for simulate the entire blasting process, starting from the detonation of the explosive charge, the expansion of detonation products, the action of the explosion energy on the rock, the rock failure, and ending with fragmentation and scattering of fragments. The simulation results show that the chosen method is useful for analyzing and better understanding the mechanics of rock massive failure and crack propagation. [ABSTRACT FROM AUTHOR]

A process of the development of rocks discontinuous displacement, which can occur under man's impact in fractured rock massif in the gravitational field in the vicinity of steep sides of deep pits and slopes is considered. The shift of the rock mass manifests itself in the formation of a characteristic spatial structure. In this regard, the problem of finding a characteristic surface that determines the movement of collapsing rock mass in a stress-strain rock massif is very relevant. To evaluate the consequences of the behavior of the fractured slope structure on the formed shear surface, a new computational approach is proposed. The calculations carried out represent quite accurately the processes of deformation and fracture development in the vicinity of the quarries faces and edges, without specifying a priori the most probable location of the rock displacement surface appearance in the massif. It is shown that the identified line of movement is closest to the brachistochrone, which corresponds to the physics of the motion of material points in the gravitational field. [ABSTRACT FROM AUTHOR]