Available online at www.CivileJournal.org Civil Engineering Journal (E-ISSN: 2476-3055; ISSN: 2676-6957) Vol. 10, No. 09, September, 2024 2919 Numerical Modeling the Rock Mass Stress-Strain State Near Vertical Excavations in Combined Mining Sh. Zeitinova 1 , A. Imashev 1* , N. Bakhtybayev 2 , A. Matayev 1 , A. Mussin 1* , G. Yeskenova 1 1 Abylkas Saginov Karaganda Technical University, Karaganda, 100012, Kazakhstan. 2 Mining Research Group LLP, Karaganda, 100022, Kazakhstan. Received 01 November 2023; Revised 21 August 2024; Accepted 27 August 2024; Published 01 September 2024 Abstract In recent years, the development of the mining industry in the Republic of Kazakhstan has been accompanied by the commissioning of new underground levels for many existing mineral deposits, which were initially developed through open-pit mining. As the depth of open-pit mining increases, the volume of overburden rises sharply, making open-pit mining unprofitable due to the significant amount of additional mining work required. For this reason, most open-pit mines in Kazakhstan are transitioning to underground mining, or combined mining. Many researchers have examined the timing of this transition and have worked on optimizing it to determine the best economic efficiency and manage risks. However, there is limited information available on how to determine the optimal location for a vertical mine shaft when transitioning from open-pit to underground mining. The purpose of this study is to identify a safe location for a vertical shaft in combined mining operations. Specifically, the study assesses the impact of the open-pit mine on the selection of the mine shaft’s location, considering the stress-strain state of the rock mass during combined mining methods. To address these objectives, numerical modeling of the stress-strain state around vertical excavations during combined mining was performed. The results provide a solution to the critical issue of determining the location of the mine shaft in combined geotechnology and lay the groundwork for further research on shaft placement in Kazakhstan. The novelty of this study lies in identifying the shaft location by considering the geometric shape of the open-pit mine and the depth of development. Keywords: Combined Development; Stress-Strain State of the Massif; Vertical Shaft; Open Pit; Rocks; Finite Element Method. 1. Introduction The experience of ore deposits open-pit mining (combined mining) in Kazakhstan and the world using schemes for opening sub-quarry reserves with vertical shafts is considered. Practice confirms that when minerals are located deposited in deposits, combined mining is used—first, the upper part is developed in an open way, then, based on economic feasibility, the transition to an underground method is carried out [1, 2]. A Shaft location should be determined taking into account the potential slope slickenside in combined technology [3]. It is known from theory and practice that the location of mine shafts significantly affects the capital costs of opening and preparing a deposit, transport, ventilation, drainage, etc. [4]. In order to study the problem of choosing a rational location of vertical mine shafts in conditions of combined geotechnology, previous works were studied. The well-known methods for determining the location of the shaft during the underground mining of deposits by privies studies were considered [5-7]. * Corresponding author: a.imashev@kstu.kz; a.musin@kstu.kz http://dx.doi.org/10.28991/CEJ-2024-010-09-010 © 2024 by the authors. Licensee C.E.J, Tehran, Iran. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).