Purpose. The assessment of options for opening and mining the upper tier of Oleniy Ruchey apatite nepheline deposits and technological solutions development taking into account geomechanical calculations of open pit slopes and benches stability, both on the marginal contour and when changing the design values of the slope parameters, open pit benches and the stability safety factor to establish the marginal maximum accepted under the condition of the values stability.Methodology. Searching for technological solutions of mining is based on the method of mining and geometric analysis of the deposit upper tier, comparison, generalization, systematization, analytical calculations, 3D parametric modeling, threedimen sional numerical modeling of stressstrain state and the rock mass stability by the finite element method.findings. According to the research results, the optimal development of mining operations has been proposed for an option providing for the minimum overburden ratio. The parameters of the highwall slopes and their elements on the marginal contour and the development of the deposit are recommended according to the option that provides the maximum possible involvement in the development of the adjacent rock mass and pit reserves mining within the existing limits of the open pit mining tap.originality. It consists in feasibility evaluation of using a rational technology for the development of mining operations accord ing to the option that provides for the minimum overburden ratio and possible mining development schemes for mining open pit reserves with an assessment of the possibility of internal dumping during the development of an open pit.Practical value. The calculations show that for the conditions of a lying side, the normative factor of the slope stability on the marginal contour can be ensured only if they are bank slopes worked along the weakening surfaces, whose cutting should not be permitted.

Purpose. Research into influence of drilling-and-blasting operations on the nature of deformation in near-side masses of the design open-pit contours and assessing the seismic impact of blasting operations, which are the basis for development of recommendations on the rational parameters of drilling-and-blasting operations. Methods. The influence of drilling-and-blasting operations at the limiting contour of the Kusmuryn field is studied using the analysis of the mining-and-geological conditions and tectonics of the rocks constituing the field, in-situ surveying the state of the open-pit sides, analysis of the physical and mechanical properties of the host rocks, analytical studies and instrumental measurements of the blasting effect. Findings. Based on the analytical methods, the calculation and analysis of the seismic stability of the rocks at the field have been performed. By means of instrumental measurement of the blasting effect in open pit, data have been obtained on the seismic impact of blasting operations on the near-side masses. According to the results of these works, rational parameters of drilling-and-blasting operations at the limiting contour of the open pit have been determined. In addition, the main provisions for the organization of drilling-and-blasting operations at the limiting contour of the open pit have been developed. Originality. In this work, for the first time, a joint research method is applied, which includes an analytical calculation of the shock wave seismic impact on a rock mass, based on the results of which the dependency graphs have been obtained of the seismicity coefficient on the rock hardness coefficient at the Kusmuryn field according to the Protodyakonov scale for various explosives, as well as using the method of instrumental measurements, which serves to determine the seismic impact of an explosion on a rock mass. This makes it possible to substantiate the technology of conducting the drilling-and-blasting operations at the contour, providing a long-term stable position of the permanent side of the open pit. Practical implications. The results of the work will be used to calculate the safe parameters of conducting the blasting operations when placing the side in the final position at the Kusmuryn field. This research method can be applied at any mining enterprise conducting open-cut mining of minerals.