Research into mass stress and failure zone parameters during blasting of fractured high benches using blasthole charges

Purpose.The paper focuses on the study of the stress distribution patterns in fractured rock masses during rock breaking on high benches using blasthole explosive charges. The research aims to optimize the parameters of drilling-blasting operations through detailed analysis of stress distribution and formation of failure zones on high benches. This will significantly improve the handling equipment operating efficiency, as well as develop economically feasible blasting patterns tailored to quarry geometry. Methods. The research is based on theoretical modeling of stress propagation caused by detonating the blasthole explosive charges in fractured rock masses. The stress distribution around the charge is calculated using equations derived from elastic deformation and surface wave theory, taking into account the particular characteristics of fractured high benches. The model includes stress propagation, wave transformation, and rock fracture behavior to identify rock crushing zones. Findings. The results have revealed that the main factor of rock failure is tensile stress waves resulting from the reflection of compression waves. The degree of rock crushing and the volume of failure zones depend on the length and diameter of the blasthole explosive charge, the properties of the explosive agent, as well as the network of pre-existing fractures. Originality. A new approach to studying the stress distribution in fractured rock masses during blasting operations is presented. This paper takes into account the influence of existing fractures and the interaction of stress waves with natural disturbances in the rock, thus allowing more accurate prediction of rock crushing. For the mining conditions of the Pustynnoye Deposit, the ratios between the radii of failure zones and the value of breaking stresses have been found, and a function for determining the failure radius has been proposed. Practical implications. The results of this research can be used to optimize the parameters of blasting operations in quarries with fractured high benches. By determining the optimal sizes and placement of charges, it is possible to achieve more efficient rock crushing, reduce equipment wear and improve overall production efficiency.