The stress wave generated by rock blasting causes vibrations in the off-contour massif. The rock strength is significantly reduced in those off-contour massif areas where the permissible velocity is exceeded. This can lead to the collapse of nearby ledges. The aims of the study are to develop a methodology for determining the boundary of the off-contour massif seismically hazardous zone, as well as to assess the well delay interval effect on the hazardous zone boundary position. Elastic vibrations of the off-contour rock under the effect of a blast wave are considered. The dependence of the rock mass displacement under the action of stress is a function of time and distance from the blast site. A series of production experiments were conducted at the “Valley” quarry of Amur Minerals JSC to determine the coefficients values that take into account the attenuation of the stress wave in the rock with increasing distance from the blast site. A method to determine the position of the off-contour massif boundary has been developed. Beyond that boundary the rate of rock displacement does not exceed the permissible value. The initial data for the calculation are the rock mass physical and mechanical characteristics and the parameters of the explosives used. In the Simulink environment a simulation model was developed to implement the described method. A methodology for energy assessment of the process of rock displacement under the effect of a stress wave was developed to verify the modeling results. By analy-zing the results obtained, a conclusion was made about the sufficient accuracy of the proposed method for practical calculations. Displacement energy values of the same point of the off-contour massif are compared at different well delay interval. Rock blasting with increased well delay intervals allows to improve the off-contour massif safety, as well as the overlying horizons ledges. The quality of blasted rock loosening is maintained.

The possibility of elements from a foam plastics use for creation of air gaps deep-hole charge is analyzed. The requests to elements used in various types of slits are formulated. Is revealed, that the elements of the cubic form are most universal and approach for shaping air gaps in any types of slits.

The complex of measures for increasing the time of explosion impact on the rock mass is analyzed. The results of experimental explosions with different types of boreholes are given. It is revealed that the use of a special locking baffle together with the formation of air gaps inside the charge and under the baffle improves the quality of crushing with a simultaneous reduction in the consumption of explosives.

At the 1st International Scientific Conference on Physical Problems of Rock Fracture we presented the results of scientific and technological substantiation of progressive technology of open-pit mining based on a fundamentally new approach to drilling and blasting operations: rock fracturing is carried out by layer-by-layer (from top to bottom) blasting of horizontal borehole charges of reduced diameter (with preliminary slotting along the contour of the blasted volume) under a mobile shelter in the form of a shield with damping elements.