The article describes the problem of reducing the competitiveness of mining enterprises due to the rising costs for transporting the rock mass due to the emergence of a mutual discrepancy between the transport system and the mining and technical system of the open-pit mine. The approach to the design of the mining and technical systems of deep open-pit mines is described being based on the consideration of the reliability of the technical subsystem that ensures the cargo turnover of rock mass. The formation of stable cargo turnover of rock mass is an urgent scientific and practical task to ensure the competitiveness of a mining enterprise. The parameters and indicators of subsystems of the mining and technical system have a large number of interrelations and change during the life of the open-pit mine, their formation is considered as a set of mining and transport equipment that comprise geotechnical complexes – drilling-and-blasting, excavator-and-vehicle, crushing-and-conveyor, crushing-and-reloading, etc., which are the main link for the extraction and delivery of minerals to the daylight surface. The mathematical models of the reliability of cargo flows formed by the technical subsystem of the mining and technical system of open-pit mine are presented, taking into account the relationship between the reliability of the system and the operational reliability of its constituent mining and transport equipment (vehicle, railway and conveyor transport, drilling rigs, excavators) under various interaction schemes. These relationships can be used for modeling both in the process of designing the mining and technical systems of open-pit mines, and in analyzing the reliability of individual schemes for transporting the rock mass and the entire transport system. The purpose of the research is to develop schemes and mathematical models for determining the reliability of cargo turnover provided by the technical subsystem of the open-pit mine (a combination of geotechnical complexes that have a significant impact on the technological subsystem, cargo turnover and productivity of the open-pit mine).