New method for determining the parameters of drilling and blasting for raising mine workings

Purpose. Development of new methods for calculating the parameters of drilling and blasting (D&B) for raising mine workings using the methods of blast-hole and well charges, taking into account the pressure of the explosion products, the compressive strength of rocks, their structural structure, fracturing and compaction under the influence of rock pressure. The methodology of research. To develop methods for calculating the parameters of D&B when carrying out raising with the help of blast-hole and well charges, we used the well-known laws of the theory of elasticity and the basic provisions of the quasi-static wave hypothesis of the mechanism of destruction of a solid medium by an explosion. To determine the zones of inelastic deformations due to changes in the stress-strain state of the rock mass in the face of the rock riser during the explosion, numerical modeling the parameters of D&B calculated using the new method was carried out using the finite element method in the software product for engineering analysis SolidWorks Simulation. Findings. Methods have been developed for calculating the parameters of D&B for carrying out raising mine workings using the methods of blast-hole and well charges. It has been established that the calculation the parameters of the D&B is carried out in the same sequence as when carrying out horizontal mine workings, but differs in that when carrying out raising there is no group of breakout blast-holes or wells. This is due to the fact that the cross-sectional area of the risers is of small importance. In the proposed methods, the distance between blast-holes or wells in a cutting is determined by the radius of the crushing zone, and for contour ones - by the radius of the intensive crushing zone. To check the calculated parameters of the D&B, using a new method, during the excavation of risers, in the conditions of the “Yuvileina” mine of PJSC “Sukha Balka”, numerical modeling of changes in the stress-strain state of the rock mass under the influence of an explosion was carried out. According to the results of numerical modeling, the formation of areas of inelastic deformation in the face of the rising under explosive load, uniform crushing of the rock was obtained, which will avoid the release of oversized pieces after the explosion. The originality. The location of blast-holes or wells in the face of the raise can be determined by the power-law dependence of the change in the line of least resistance (LLR) on their diameter, the pressure of the explosion products, the compressive strength of rocks, their structural structure, fracturing and compaction under the influence of rock pressure. Practical implications. The developed methods for determining the parameters of D&B for carrying out the risers methods of blast-hole and well charges make it possible to rationalize the location of blast-holes or wells in the face, which will lead to resource saving during their implementation.