Relevance. Long periods of development of steeply dipping deposits necessitate multiple adjustments of mining and technical system throughout an open pit life cycle. The decisions made determine the development strategy of a mining enterprise for a long period. The complexity of making such strategic decisions depends on numerous influencing parameters. These parameters have a different impact, have a variety of units of measurement, target values, and are not only quantitative but also qualitative. There is a need for new approaches to the choice of development strategy of the mining and technical system of an open pit, as well as its main subsystem – the opening-up of an opencast system. It is proposed to base these approaches on multi-criteria decision-making methods that consider many influencing parameters. Aim. Development of a methodology for choosing a strategy for sustainable development of the deep open pit mining and technical system based on multi-criteria decision-making methods and assessment of the opening system parameters. Objects. Mining enterprise, mining and technical systems, opening system. Methods. Literature review, system analysis, multi-criteria decision making.   Results. The authors have determined the main strategies for development of the mining and technical system for deep open pits. These strategies aim at achieving the sustainable development of the mining and technical system: adjustment of the current stage mining parameters; transition to a new stage of mining; transition to a combined open-underground mining; mine closure. The key role of the opening system in the structure of the mining and technical system is substantiated to ensure its sustainable development. The authors systematized the main parameters for evaluating the pit opening system and set target values for each parameter. A review of the main multi-criteria decision-making methods used to solve various problems in the mining industry is made. A rank coefficient is proposed for choosing the mining and technical system development strategy. The calculation of this coefficient is based on a combination of the fuzzy AHP and CRADIS multi-criteria methods. A method was developed for selecting a strategy for sustainable development of the mining and technical system of deep open pits. A case study was conducted on the conditions of the Maly Kuibas open pit. The obtained results strongly suggest that the best strategy with the highest ranking is the transition to the combined development method.