Cost Drivers Affecting the Ultimate Pit Limit Determination in Open-Pit Mining: A Case of Kazakhstan

Abstract

Ultimate pit limit (UPL) identification is a foundational step of open-pit mine planning, since it determines the economically recoverable limit of a deposit within specified technical and economic conditions. This research examines the impact of cost structure and price fluctuations on the definition of UPL in open-pit mining, with particular emphasis on the economic context of Kazakhstan. Geological and geotechnical variables remained constant, while economic data were modified using Kazakhstan-specific price and cost data from KazMinerals for the period 2016–2020. Economic block values were recomputed and optimized using a pseudoflow-based implementation of the Lerchs–Grossmann pit optimization. The results demonstrate that regional economic variables significantly influence economic block values, ultimate pit size, and total project value, highlighting the importance of integrating region-specific economic parameters into mine planning operations.